Guixiang Zhang - Academia.edu (original) (raw)

Papers by Guixiang Zhang

Research paper thumbnail of Blood-brain barrier-crossing dendrimers for glioma theranostics

Biomaterials science, 2023

Research paper thumbnail of Phosphorus core–shell tecto dendrimers for enhanced tumor imaging: the rigidity of the backbone matters

Biomaterials Science, Dec 31, 2022

Research paper thumbnail of Imaging Quality Evaluation of Low Tube Voltage Coronary CT Angiography Using Low Concentration Contrast Medium

PLOS ONE, Mar 26, 2015

To compare the image quality of prospectively ECG-gated low voltage coronary computed tomography ... more To compare the image quality of prospectively ECG-gated low voltage coronary computed tomography angiography (CTA) with an administration of low concentration contrast medium. Method and Materials A total of 101 patients, each with a heart rate below 65 beats per minute (BPM), underwent a prospectively ECG-gated axial scan in CT coronary angiography on a 64-slice CT scanner. All patients were allocated in three groups (group A: n=31, 80kVp, 300 mgI/ml; group B: n=34, 100kVp, 300 mgI/ml; group C: n=36, 120kVp, 370 mgI/ml). The CT attenuation values of aortic root (AR), left main coronary artery (LMA), right main coronary artery (RMA) and chest subcutaneous fat tissue were measured. The contrast-to-noise ratio (CNR) of AR, LMA and RMA were calculated according to the formulas below. The values of computed tomography dose index (CTDI) and dose-length product (DLP) were recorded. Image quality was assessed on a 5-point scale. The results were compared using the one-way ANOVA and rank sum tests. Results The values of CNR and SNR for vessels in group A and group B were not significantly different from group C (each p > 0.05). The effective radiation dose in group A (1.51±0.70 mSv) and group B (2.59±1.24 mSv) were both lower than group C (4.92±2.82 mSv) (each p < 0.05). There was no significant difference among the image quality scores of group A (4.10±0.41), group B (3.90±0.48) and group C (4.04±0.36) (each P > 0.05).

Research paper thumbnail of Targeted CT/MR dual mode imaging of human hepatocellular carcinoma using lactobionic acid-modified polyethyleneimine-entrapped gold nanoparticles

Journal of Materials Chemistry B, 2017

Materials Branched PEI (Mw = 25000), 1-ethyl-3-(3-(dimethylamino)propyl) carbodiimide hydrochlori... more Materials Branched PEI (Mw = 25000), 1-ethyl-3-(3-(dimethylamino)propyl) carbodiimide hydrochloride (EDC), and 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) were procured from Sigma-Aldrich (St. Louis, MO). Methoxy-poly (ethylene glycol)-carboxylic acid (mPEG-COOH) and amino-poly (ethylene glycol)-carboxylic acid (NH 2-PEG-COOH) with Mw 2000 were supplied from Shanghai Yanyi Biotechnology Corporation (Shanghai, China). 2,2',2''-(10-(2-(2,5-Dioxopyrrolidin-1yloxy)-2-oxoethyl)-1,4,7,10-tetraazacyclododecane-1,4,7-triyl) triacetic acid (DOTA-NHS) was purchased by CheMatech (Dijon, France). Sodium borohydride, LA, acetic anhydride, triethylamine, and all the other chemicals and solvents were from Sinopharm Chemical Reagent Co., Ltd. (Shanghai, China). HepG2 cells (Hepatocellular Carcinoma cell line) were supplied by Institute of Biochemistry and Cell Biology, the Chinese Academy of Sciences (Shanghai, China). Fetal bovine serum (FBS) was obtained from HyClone Lab., Inc. (Logan, UT). Dulbecco's modified eagle's medium (DMEM), penicillin, and streptomycin were from Hangzhou Jinuo Biomedical Technology (Hangzhou, China). Cellulose dialysis membranes (molecular weight cutoff , MWCO = 14,000 or 2,000) were purchased from Shanghai Yuanye Biotechnology Co., Ltd. (Shanghai, China). Synthesis of LA-PEG-COOH LA-PEG-COOH was synthesized according to the literature. 1 In brief, LA (53.7 mg, 20 mL in water) was activated by 57.2 mg EDC under vigorous stirring. Three hours later, the activated LA was added to the water solution of NH 2-PEG-COOH (200 mg, 40 mL) and kept stirring for 3 days. Then, the reaction mixture was dialyzed to remove the excess reactants and by-products to get the product LA-PEG-COOH via lyophilization. Synthesis of Gd-Au PENPs-LA DOTA-NHS (20 mg, 5 mL in water) was added to a water solution of PEI (50.0 mg, 15 mL) with vigorous stirring to form the raw product of PEI-DOTA. After 24 h, EDC-activated LA-PEG-COOH (117.7 mg, 5 mL in water) was added to the above solution and the mixture was kept stirring for 48 h

Research paper thumbnail of Multifunctional dendrimer-based nanoparticles for in vivo MR/CT dual-modal molecular imaging of breast cancer

International Journal of Nanomedicine, Jul 1, 2013

Development of dual-mode or multi-mode imaging contrast agents is important for accurate and self... more Development of dual-mode or multi-mode imaging contrast agents is important for accurate and self-confirmatory diagnosis of cancer. We report a new multifunctional, dendrimer-based gold nanoparticle (AuNP) as a dual-modality contrast agent for magnetic resonance (MR)/computed tomography (CT) imaging of breast cancer cells in vitro and in vivo. In this study, amine-terminated generation 5 poly(amidoamine) dendrimers modified with gadolinium chelate (DOTA-NHS) and polyethylene glycol monomethyl ether were used as templates to synthesize AuNPs, followed by Gd(III) chelation and acetylation of the remaining dendrimer terminal amine groups; multifunctional dendrimer-entrapped AuNPs (Gd-Au DENPs) were formed. The formed Gd-Au DENPs were used for both in vitro and in vivo MR/CT imaging of human MCF-7 cancer cells. Both MR and CT images demonstrate that MCF-7 cells and the xenograft tumor model can be effectively imaged. The Gd-Au DENPs uptake, mainly in the cell cytoplasm, was confirmed by transmission electron microscopy. The cell cytotoxicity assay, cell morphology observation, and flow cytometry show that the developed Gd-Au DENPs have good biocompatibility in the given concentration range. Our results clearly suggest that the synthetic Gd-Au DENPs are amenable for dual-modality MR/CT imaging of breast cancer cells.

Research paper thumbnail of Dendrimer-Assisted Formation of Fe<sub>3</sub>O<sub>4</sub>/Au Nanocomposite Particles for Targeted Dual Mode CT/MR Imaging of Tumors

Small, Jun 10, 2015

A unique dendrimer-assisted approach is reported to create Fe3 O4 /Au nanocomposite particles (NC... more A unique dendrimer-assisted approach is reported to create Fe3 O4 /Au nanocomposite particles (NCPs) for targeted dual mode computed tomography/magnetic resonance (CT/MR) imaging of tumors. In this approach, preformed Fe3 O4 nanoparticles (NPs) are assembled with multilayers of poly(γ-glutamic acid) (PGA)/poly(l-lysine)/PGA/folic acid (FA)-modified dendrimer-entrapped gold nanoparticles via a layer-by-layer self-assembly technique. The interlayers are crosslinked via 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide chemistry, the assembled Au core NPs are then used as seed particles for subsequent seed-mediated growth of Au shells via iterative Au salt reduction process, and subsequent acetylation of the remaining amines of dendrimers leads to the formation of Fe3 O4 /Aun .Ac-FA NCPs with a tunable molar ratio of Au/Fe3 O4 . It is shown that the Fe3 O4 /Aun. Ac-FA NCPs at an optimized Au/Fe3 O4 molar ratio of 2.02 display a relatively high R2 relaxivity (92.67 × 10(-3) M(-1) s(-1) ) and good X-ray attenuation property, and are cytocompatible and hemocompatible in the given concentration range. Importantly, with the FA-mediated targeting, the Fe3 O4 /Aun. Ac-FA NCPs are able to be specifically uptaken by cancer cells overexpressing FA receptors, and be used as an efficient nanoprobe for targeted dual mode CT/MR imaging of a xenografted tumor model. With the versatile dendrimer chemistry, the developed Fe3 O4 /Au NCPs may be differently functionalized, thereby providing a unique platform for diagnosis and therapy of different biological systems.

Research paper thumbnail of Targeted cancer theranostics using alpha-tocopheryl succinate-conjugated multifunctional dendrimer-entrapped gold nanoparticles

Biomaterials, Aug 1, 2014

Development of multifunctional theranostic nanoplatforms for targeted cancer imaging and therapy ... more Development of multifunctional theranostic nanoplatforms for targeted cancer imaging and therapy still remains a great challenge. Herein, we report the use of multifunctional dendrimer-entrapped gold nanoparticles (Au DENPs) covalently linked with a-tocopheryl succinate (a-TOS) as a platform for targeted cancer computed tomography (CT) imaging and therapy. In this study, amine-terminated poly(amidoamine) dendrimers of generation 5 (G5.NH 2) conjugated with fluorescein isothiocyanate (FI), polyethylene glycol (PEG)-modified a-TOS, and PEGylated folic acid (FA) were used as templates to synthesize Au DENPs, followed by acetylation of the remaining dendrimer terminal amines. The formed multifunctional Au DENPs were characterized via different techniques. We show that the Au DENPs conjugated with approximately 9.8 a-TOS molecules per dendrimer and with an Au core size of 3.3 nm are water-dispersible, and stable under different pH and temperature conditions and in different aqueous media. The FA modification onto the Au DENPs enables efficient targeting of the particles to cancer cells overexpressing FA receptors (FAR), and effective targeted CT imaging of the cancer cells in vitro and the xenografted tumor model in vivo. Likewise, the covalent conjugation of a-TOS does not compromise its therapeutic activity, instead significantly improves its water solubility. Importantly, thanks to the role of FA-directed targeting, the formed multifunctional Au DENPs are able to exert the specific therapeutic efficacy of a-TOS to the FAR-overexpressing cancer cells in vitro and the xenografted tumor model in vivo. The developed multifunctional Au DENPs may hold a great promise to be used as a unique theranostic nanoplatform for targeted CT imaging and therapy of different types of cancer.

Research paper thumbnail of Targeted CT/MR dual mode imaging of tumors using multifunctional dendrimer-entrapped gold nanoparticles

Biomaterials, Jul 1, 2013

We report the synthesis and characterization of folic acid (FA)-modified multifunctional dendrime... more We report the synthesis and characterization of folic acid (FA)-modified multifunctional dendrimer-entrapped gold nanoparticles (Au DENPs) loaded with gadolinium (Gd) for targeted dual mode computed tomography (CT)/magnetic resonance (MR) imaging of tumors. In this work, amine-terminated generation 5 poly(amidoamine) dendrimers (G5.NH2) modified with Gd(III) chelator, polyethylene glycol (PEG) monomethyl ether, and PEGylated FA were used as templates to entrap gold nanoparticles (AuNPs). Further chelation of Gd(III) ions and acetylation of the remaining dendrimer terminal amines led to the formation of multifunctional FA-targeted Au DENPs loaded with Gd(III) (Gd-Au DENPs-FA). The formed Gd-Au DENPs-FA probes were characterized via different techniques. We show that the Gd-Au DENPs-FA probes with an Au NP core size of 4.0 nm are water dispersible, stable under different pH and temperature conditions, and cytocompatible in the given concentration range. With the co-existence of AuNPs and Gd(III) ions within the single multifunctional particles, Gd-Au DENPs-FA displayed high X-ray attenuation intensity and reasonable r1 relaxivity. These properties of the particles enabled them to be used as dual mode nanoprobes for targeted CT/MR imaging of cancer cells in vitro and xenograft tumor model in vivo via FA receptor-mediated active targeting pathway. The strategy to design multifunctional nanoprobes using the versatile dendrimer nanotechnology may be extended to design various dual mode or multimode imaging agents for accurate diagnosis of different types of cancer.

Research paper thumbnail of Multifunctional dendrimer-entrapped gold nanoparticles for dual mode CT/MR imaging applications

Biomaterials, Feb 1, 2013

We report the synthesis, characterization, and utilization of gadolium-loaded dendrimer-entrapped... more We report the synthesis, characterization, and utilization of gadolium-loaded dendrimer-entrapped gold nanoparticles (GdeAu DENPs) for dual mode computed tomography (CT)/magnetic resonance (MR) imaging applications. In this study, amine-terminated generation five poly(amidoamine) dendrimers (G5.NH 2) modified with gadolinium (Gd) chelator and polyethylene glycol (PEG) monomethyl ether were used as templates to synthesize gold nanoparticles (AuNPs). Followed by sequential chelation of Gd(III) and acetylation of the remaining dendrimer terminal amine groups, multifunctional GdeAu DENPs were formed. The formed GdeAu DENPs were characterized via different techniques. We show that the formed GdeAu DENPs are colloidally stable and non-cytotoxic at an Au concentration up to 50 mM. With the coexistence of two radiodense imaging elements of AuNPs and Gd(III) within one NP system, the formed GdeAu DENPs display both r 1 relaxivity for MR imaging mode and X-ray attenuation property for CT imaging mode, which enables CT/MR dual mode imaging of the heart, liver, kidney, and bladder of rat or mouse within a time frame of 45 min. Furthermore, in vivo biodistribution studies reveal that the GdeAu DENPs have an extended blood circulation time and can be cleared from the major organs within 24 h. The strategy to use facile dendrimer technology to design dual mode contrast agents may be extended to prepare multifunctional platforms for targeted multimode molecular imaging of various biological systems.

Research paper thumbnail of Facile Hydrothermal Synthesis and Surface Functionalization of Polyethyleneimine-Coated Iron Oxide Nanoparticles for Biomedical Applications

ACS Applied Materials & Interfaces, Feb 19, 2013

We report the facile hydrothermal synthesis and surface functionalization of branched polyethylen... more We report the facile hydrothermal synthesis and surface functionalization of branched polyethyleneimine (PEI)-coated iron oxide nanoparticles (Fe 3 O 4 −PEI NPs) for biomedical applications. In this study, Fe 3 O 4 −PEI NPs were synthesized via a one-pot hydrothermal method in the presence of PEI. The formed Fe 3 O 4 −PEI NPs with primary amine groups on the surface were able to be further functionalized with polyethylene glycol (PEG), acetic anhydride, and succinic anhydride, respectively. The formed pristine and functionalized Fe 3 O 4 −PEI NPs were characterized via different techniques. We showed that the sizes of the Fe 3 O 4 −PEI NPs were able to be controlled by varying the mass ratio of Fe(II) salt and PEI. In addition, the formed Fe 3 O 4 −PEI NPs with different surface functionalities had good water dispersibility, colloidal stability, and relatively high R 2 relaxivity (130− 160 1/(mM•s)). Cell viability assay data revealed that the surface PEGylation and acylation of Fe 3 O 4 −PEI NPs rendered them with good biocompatibility in the given concentration range, while the pristine aminated Fe 3 O 4 −PEI NPs started to display slight toxicity at the concentration of 50 μg/mL. Importantly, macrophage cellular uptake results demonstrated that both PEGylation and acetylation of Fe 3 O 4 −PEI NPs were able to significantly reduce the nonspecific macrophage uptake, likely rendering the particles with prolonged circulation time. With the proven hemocompatibility and rich amine conjugation chemistry, the Fe 3 O 4 − PEI NPs with different surface functionalities may be applied for various biomedical applications, especially for magnetic resonance imaging and therapy.

Research paper thumbnail of Low kilovoltage peak (kVp) with an adaptive statistical iterative reconstruction algorithm in computed tomography urography: evaluation of image quality and radiation dose

PubMed, 2016

Purpose: The purpose of this study was to evaluate the image quality and radiation dose in comput... more Purpose: The purpose of this study was to evaluate the image quality and radiation dose in computed tomography urography (CTU) images acquired with a low kilovoltage peak (kVp) in combination with an adaptive statistical iterative reconstruction (ASiR) algorithm. Methods: A total of 45 subjects (18 women, 27 men) who underwent CTU with kV assist software for automatic selection of the optimal kVp were included and divided into two groups (A and B) based on the kVp and image reconstruction algorithm: group A consisted of patients who underwent CTU with a 80 or 100 kVp and whose images were reconstructed with the 50% ASiR algorithm (n=32); group B consisted of patients who underwent CTU with a 120 kVp and whose images were reconstructed with the filtered back projection (FBP) algorithm (n=13). The images were separately reconstructed with volume rendering (VR) and maximum intensity projection (MIP). Finally, the image quality was evaluated using an image score, CT attenuation, image noise, the contrast-to-noise ratio (CNR) of the renal pelvis-to-abdominal visceral fat and the signal-to-noise ratio (SNR) of the renal pelvis. The radiation dose was assessed using volume CT dose index (CTDIvol), dose-length product (DLP) and effective dose (ED). Results: For groups A and B, the subjective image scores for the VR reconstruction images were 3.9±0.4 and 3.8±0.4, respectively, while those for the MIP reconstruction images were 3.8±0.4 and 3.6±0.6, respectively. No significant difference was found (p>0.05) between the two groups' image scores for either the VR or MIP reconstruction images. Additionally, the inter-reviewer image scores did not significantly differ (p>0.05). The mean attenuation of the bilateral renal pelvis in group A was significantly higher than that in group B (271.4±57.6 vs. 221.8±35.3 HU, p<0.05), whereas the image noise in group A was significantly lower than that in group B (7.9±2.1 vs. 10.5±2.3 HU, p<0.05). The CNR and SNR in group A were both significantly higher than those in group B (53.61±24.74 vs. 32.30±6.52 for CNR; 38.13±19.86 vs. 21.76±4.85 for SNR; all p<0.05). The CTDIvol, DLP and ED in group A were significantly lower than those in group B (9.26±2.77 vs. 16.19±5.60 mGy for CTDIvol; 368.86±119.38 vs. 674.38±239.37 mGy×cm-1 for DLP; 5.53±1.79 vs. 10.12±3.59 mSv for ED; all p<0.05). Conclusions: The low kVp CTU images with 50% ASiR reconstruction exhibit sufficient image quality and facilitate up to a 44% radiation dose reduction.

Research paper thumbnail of Arg-Gly-Asp-D-Phe-Lys peptide-modified PEGylated dendrimer-entrapped gold nanoparticles for targeted computed tomography imaging of breast carcinoma

Nanomedicine, Jul 1, 2015

To investigate cyclo (Arg-Gly-Asp-D-Phe-Lys) peptide (RGD)-modified PEGylated dendrimer-entrapped... more To investigate cyclo (Arg-Gly-Asp-D-Phe-Lys) peptide (RGD)-modified PEGylated dendrimer-entrapped gold nanoparticles (PEGylated Au DENPs-RGD) for targeted computed tomography (CT) imaging of breast carcinomas. Materials & methods: PEGylated Au DENPs-RGD were synthesized and characterized. Then, the PEGylated Au DENPs-RGD for targeted CT imaging were investigated using the MDA-MB-435 cell line, an integrin-rich breast carcinoma cells, and mice with MDA-MB-435 xenograft tumors. Finally, silver enhancement staining and integrin α v β 3 immunohistochemistry of the tumors were performed. Results: The synthesized PEGylated Au DENPs-RGD were spherical, water dispersible and biocompatible nanoprobes with a gold nanoparticle core size of 2.8 nm. Due to the presence of the Au nanoparticles, the PEGylated Au DENPs-RGD displayed a higher x-ray attenuation intensity than Omnipaque at the same Au or I concentrations. The conjugated RGD ligand can specifically identify and target overexpressed integrin receptors on MDA-MB-435 cells. After intravenous injection, these nanoprobes accumulated in the targeted area of mice with MDA-MB-435 xenograft tumors, which enabled the tumor to be detected by CT imaging. The histological results confirmed the imaging results. Conclusion: The PEGylated Au DENPs-RGD can be used as targeted nanoprobes with good biocompatibility for targeted CT imaging and diagnosis of integrin-positive tumors.

Research paper thumbnail of Dendrimer-entrapped gold nanoparticles as potential CT contrast agents for blood pool imaging

Nanoscale Research Letters, Mar 19, 2012

The purpose of this study was to evaluate dendrimer-entrapped gold nanoparticles [Au DENPs] as a ... more The purpose of this study was to evaluate dendrimer-entrapped gold nanoparticles [Au DENPs] as a molecular imaging [MI] probe for computed tomography [CT]. Au DENPs were prepared by complexing AuCl 4 ions with amine-terminated generation 5 poly(amidoamine) [G5.NH 2 ] dendrimers. Resulting particles were sized using transmission electron microscopy. Serial dilutions (0.001 to 0.1 M) of either Au DENPs or iohexol were scanned by CT in vitro. Based on these results, Au DENPs were injected into mice, either subcutaneously (10 μL, 0.007 to 0.02 M) or intravenously (300 μL, 0.2 M), after which the mice were imaged by micro-CT or a standard mammography unit. Au DENPs prepared using G5.NH 2 dendrimers as templates are quite uniform and have a size range of 2 to 4 nm. At Au concentrations above 0.01 M, the CT value of Au DENPs was higher than that of iohexol. A 10-μL subcutaneous dose of Au DENPs with [Au] ≥ 0.009 M could be detected by micro-CT. The vascular system could be imaged 5 and 20 min after injection of Au DENPs into the tail vein, and the urinary system could be imaged after 60 min. At comparable time points, the vascular system could not be imaged using iohexol, and the urinary system was imaged only indistinctly. Findings from this study suggested that Au DENPs prepared using G5.NH 2 dendrimers as templates have good X-ray attenuation and a substantial circulation time. As their abundant surface amine groups have the ability to bind to a range of biological molecules, Au DENPs have the potential to be a useful MI probe for CT.

Research paper thumbnail of PEGylated polyethylenimine-entrapped gold nanoparticles modified with folic acid for targeted tumor CT imaging

Colloids and Surfaces B: Biointerfaces, Apr 1, 2016

Development of various cost-effective contrast agents for targeted tumor computed tomography (CT)... more Development of various cost-effective contrast agents for targeted tumor computed tomography (CT) imaging still remains a great challenge. Herein, we present a facile approach to forming folic acid (FA)-targeted multifunctional gold nanoparticles (AuNPs) using cost-effective branched polyethylenimine (PEI) modified with polyethylene glycol (PEG) as a template for tumor CT imaging applications. In this work, PEI sequentially modified with PEG monomethyl ether, FA-linked PEG, and fluorescein isothiocyanate was used as a template to synthesize AuNPs, followed by transformation of the remaining PEI surface amines to acetamides. The formed FA-targeted PEI-entrapped AuNPs (FA-Au PENPs) were fully characterized. We show that the formed FA-Au PENPs with an Au core size of 2.1nm are water soluble, colloidally stable, and non-cytotoxic in a given concentration range. Flow cytometry and confocal microscopy data reveal that the FA-Au PENPs are able to target cancer cells overexpressing FA receptors (FAR). Importantly, the developed FA-Au PENPs can be used as a nanoprobe for targeted CT imaging of FAR-expressing cancer cells in vitro and the xenografted tumor model in vivo. With the demonstrated biocompatibility by organ biodistribution and histological studies, the designed FA-Au PENPs may hold great promise to be used as a nanoprobe for CT imaging of different FAR-overexpressing tumors.

Research paper thumbnail of Facile assembly of Fe3O4@Au nanocomposite particles for dual mode magnetic resonance and computed tomography imaging applications

Journal of Materials Chemistry, 2012

Research paper thumbnail of X-ray Attenuation Property of Dendrimer-Entrapped Gold Nanoparticles

Journal of Physical Chemistry C, Dec 15, 2009

... 19. Kumar, S.; Harrison, N.; Richards-Kortum, R.; Sokolov, K. Nano Lett. 2007, 7, 1338 ...

Research paper thumbnail of Differentiation between adrenal adenomas and nonadenomas using dynamic contrast-enhanced computed tomography

OncoTargets and Therapy, Nov 1, 2016

This study was performed to evaluate the findings including the time density curve (TD curve), th... more This study was performed to evaluate the findings including the time density curve (TD curve), the relative percentage of enhancement washout (Washr) and the absolute percentage of enhancement washout (Washa) at dynamic contrast-enhanced computed tomography (DCE-CT) in 70 patients with 79 adrenal masses (including 44 adenomas and 35 nonadenomas) confirmed histopathologically and/or clinically. The results demonstrated that the TD curves of adrenal masses were classified into 5 types, and the type distribution of the TD curves was significantly different between adenomas and nonadenomas. Types A and C were characteristic of adenomas, whereas types B, D and E were features of nonadenomas. The sensitivity, specificity and accuracy for the diagnosis of adenoma based on the TD curves were 93%, 80% and 87%, respectively. Furthermore, when myelolipomas were excluded, the specificity and accuracy for adenoma were 90% and 92%, respectively. The Washr and the Washa values for the adenomas were higher than those for the nonadenomas. The diagnostic efficiency for adenoma was highest at 7-min delay time at DCE-CT; Washr was more efficient than Washa. Washr 34% and Washa 43% were both suggestive of adenomas and, on the contrary, suspicious of nonadenomas. The sensitivity, specificity and accuracy for the diagnosis of adenoma were 84%, 77% and 81%, respectively. When myelolipomas were precluded, the diagnostic specificity and accuracy were 87% and 85%, respectively. Therefore, DCE-CT aids in characterization of adrenal tumors, especially for lipid-poor adenomas which can be correctly categorized on the basis of TD curve combined with the percentage of enhancement washout.

Research paper thumbnail of Facile hydrothermal synthesis of low generation dendrimer-stabilized gold nanoparticles for in vivo computed tomography imaging applications

Research paper thumbnail of Magnetic resonance imaging of glioma with novel APTS-coated superparamagnetic iron oxide nanoparticles

Nanoscale Research Letters, Jun 15, 2014

We report in vitro and in vivo magnetic resonance (MR) imaging of C6 glioma cells with a novel ac... more We report in vitro and in vivo magnetic resonance (MR) imaging of C6 glioma cells with a novel acetylated 3-aminopropyltrimethoxysilane (APTS)-coated iron oxide nanoparticles (Fe 3 O 4 NPs). In the present study, APTS-coated Fe 3 O 4 NPs were formed via a one-step hydrothermal approach and then chemically modified with acetic anhydride to generate surface charge-neutralized NPs. Prussian blue staining and transmission electron microscopy (TEM) data showed that acetylated APTS-coated Fe 3 O 4 NPs can be taken up by cells. Combined morphological observation, cell viability, and flow cytometric analysis of the cell cycle indicated that the acetylated APTS-coated Fe 3 O 4 NPs did not significantly affect cell morphology, viability, or cell cycle, indicating their good biocompatibility. Finally, the acetylated APTS-coated Fe 3 O 4 nanoparticles were used in magnetic resonance imaging of C6 glioma. Our results showed that the developed acetylated APTS-coated Fe 3 O 4 NPs can be used as an effective labeling agent to detect C6 glioma cells in vitro and in vivo for MR imaging. The results from the present study indicate that the developed acetylated APTS-coated Fe 3 O 4 NPs have a potential application in MR imaging.

Research paper thumbnail of Synthesis of PEGylated low generation dendrimer-entrapped gold nanoparticles for CT imaging applications

Research paper thumbnail of Blood-brain barrier-crossing dendrimers for glioma theranostics

Biomaterials science, 2023

Research paper thumbnail of Phosphorus core–shell tecto dendrimers for enhanced tumor imaging: the rigidity of the backbone matters

Biomaterials Science, Dec 31, 2022

Research paper thumbnail of Imaging Quality Evaluation of Low Tube Voltage Coronary CT Angiography Using Low Concentration Contrast Medium

PLOS ONE, Mar 26, 2015

To compare the image quality of prospectively ECG-gated low voltage coronary computed tomography ... more To compare the image quality of prospectively ECG-gated low voltage coronary computed tomography angiography (CTA) with an administration of low concentration contrast medium. Method and Materials A total of 101 patients, each with a heart rate below 65 beats per minute (BPM), underwent a prospectively ECG-gated axial scan in CT coronary angiography on a 64-slice CT scanner. All patients were allocated in three groups (group A: n=31, 80kVp, 300 mgI/ml; group B: n=34, 100kVp, 300 mgI/ml; group C: n=36, 120kVp, 370 mgI/ml). The CT attenuation values of aortic root (AR), left main coronary artery (LMA), right main coronary artery (RMA) and chest subcutaneous fat tissue were measured. The contrast-to-noise ratio (CNR) of AR, LMA and RMA were calculated according to the formulas below. The values of computed tomography dose index (CTDI) and dose-length product (DLP) were recorded. Image quality was assessed on a 5-point scale. The results were compared using the one-way ANOVA and rank sum tests. Results The values of CNR and SNR for vessels in group A and group B were not significantly different from group C (each p > 0.05). The effective radiation dose in group A (1.51±0.70 mSv) and group B (2.59±1.24 mSv) were both lower than group C (4.92±2.82 mSv) (each p < 0.05). There was no significant difference among the image quality scores of group A (4.10±0.41), group B (3.90±0.48) and group C (4.04±0.36) (each P > 0.05).

Research paper thumbnail of Targeted CT/MR dual mode imaging of human hepatocellular carcinoma using lactobionic acid-modified polyethyleneimine-entrapped gold nanoparticles

Journal of Materials Chemistry B, 2017

Materials Branched PEI (Mw = 25000), 1-ethyl-3-(3-(dimethylamino)propyl) carbodiimide hydrochlori... more Materials Branched PEI (Mw = 25000), 1-ethyl-3-(3-(dimethylamino)propyl) carbodiimide hydrochloride (EDC), and 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) were procured from Sigma-Aldrich (St. Louis, MO). Methoxy-poly (ethylene glycol)-carboxylic acid (mPEG-COOH) and amino-poly (ethylene glycol)-carboxylic acid (NH 2-PEG-COOH) with Mw 2000 were supplied from Shanghai Yanyi Biotechnology Corporation (Shanghai, China). 2,2',2''-(10-(2-(2,5-Dioxopyrrolidin-1yloxy)-2-oxoethyl)-1,4,7,10-tetraazacyclododecane-1,4,7-triyl) triacetic acid (DOTA-NHS) was purchased by CheMatech (Dijon, France). Sodium borohydride, LA, acetic anhydride, triethylamine, and all the other chemicals and solvents were from Sinopharm Chemical Reagent Co., Ltd. (Shanghai, China). HepG2 cells (Hepatocellular Carcinoma cell line) were supplied by Institute of Biochemistry and Cell Biology, the Chinese Academy of Sciences (Shanghai, China). Fetal bovine serum (FBS) was obtained from HyClone Lab., Inc. (Logan, UT). Dulbecco's modified eagle's medium (DMEM), penicillin, and streptomycin were from Hangzhou Jinuo Biomedical Technology (Hangzhou, China). Cellulose dialysis membranes (molecular weight cutoff , MWCO = 14,000 or 2,000) were purchased from Shanghai Yuanye Biotechnology Co., Ltd. (Shanghai, China). Synthesis of LA-PEG-COOH LA-PEG-COOH was synthesized according to the literature. 1 In brief, LA (53.7 mg, 20 mL in water) was activated by 57.2 mg EDC under vigorous stirring. Three hours later, the activated LA was added to the water solution of NH 2-PEG-COOH (200 mg, 40 mL) and kept stirring for 3 days. Then, the reaction mixture was dialyzed to remove the excess reactants and by-products to get the product LA-PEG-COOH via lyophilization. Synthesis of Gd-Au PENPs-LA DOTA-NHS (20 mg, 5 mL in water) was added to a water solution of PEI (50.0 mg, 15 mL) with vigorous stirring to form the raw product of PEI-DOTA. After 24 h, EDC-activated LA-PEG-COOH (117.7 mg, 5 mL in water) was added to the above solution and the mixture was kept stirring for 48 h

Research paper thumbnail of Multifunctional dendrimer-based nanoparticles for in vivo MR/CT dual-modal molecular imaging of breast cancer

International Journal of Nanomedicine, Jul 1, 2013

Development of dual-mode or multi-mode imaging contrast agents is important for accurate and self... more Development of dual-mode or multi-mode imaging contrast agents is important for accurate and self-confirmatory diagnosis of cancer. We report a new multifunctional, dendrimer-based gold nanoparticle (AuNP) as a dual-modality contrast agent for magnetic resonance (MR)/computed tomography (CT) imaging of breast cancer cells in vitro and in vivo. In this study, amine-terminated generation 5 poly(amidoamine) dendrimers modified with gadolinium chelate (DOTA-NHS) and polyethylene glycol monomethyl ether were used as templates to synthesize AuNPs, followed by Gd(III) chelation and acetylation of the remaining dendrimer terminal amine groups; multifunctional dendrimer-entrapped AuNPs (Gd-Au DENPs) were formed. The formed Gd-Au DENPs were used for both in vitro and in vivo MR/CT imaging of human MCF-7 cancer cells. Both MR and CT images demonstrate that MCF-7 cells and the xenograft tumor model can be effectively imaged. The Gd-Au DENPs uptake, mainly in the cell cytoplasm, was confirmed by transmission electron microscopy. The cell cytotoxicity assay, cell morphology observation, and flow cytometry show that the developed Gd-Au DENPs have good biocompatibility in the given concentration range. Our results clearly suggest that the synthetic Gd-Au DENPs are amenable for dual-modality MR/CT imaging of breast cancer cells.

Research paper thumbnail of Dendrimer-Assisted Formation of Fe<sub>3</sub>O<sub>4</sub>/Au Nanocomposite Particles for Targeted Dual Mode CT/MR Imaging of Tumors

Small, Jun 10, 2015

A unique dendrimer-assisted approach is reported to create Fe3 O4 /Au nanocomposite particles (NC... more A unique dendrimer-assisted approach is reported to create Fe3 O4 /Au nanocomposite particles (NCPs) for targeted dual mode computed tomography/magnetic resonance (CT/MR) imaging of tumors. In this approach, preformed Fe3 O4 nanoparticles (NPs) are assembled with multilayers of poly(γ-glutamic acid) (PGA)/poly(l-lysine)/PGA/folic acid (FA)-modified dendrimer-entrapped gold nanoparticles via a layer-by-layer self-assembly technique. The interlayers are crosslinked via 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide chemistry, the assembled Au core NPs are then used as seed particles for subsequent seed-mediated growth of Au shells via iterative Au salt reduction process, and subsequent acetylation of the remaining amines of dendrimers leads to the formation of Fe3 O4 /Aun .Ac-FA NCPs with a tunable molar ratio of Au/Fe3 O4 . It is shown that the Fe3 O4 /Aun. Ac-FA NCPs at an optimized Au/Fe3 O4 molar ratio of 2.02 display a relatively high R2 relaxivity (92.67 × 10(-3) M(-1) s(-1) ) and good X-ray attenuation property, and are cytocompatible and hemocompatible in the given concentration range. Importantly, with the FA-mediated targeting, the Fe3 O4 /Aun. Ac-FA NCPs are able to be specifically uptaken by cancer cells overexpressing FA receptors, and be used as an efficient nanoprobe for targeted dual mode CT/MR imaging of a xenografted tumor model. With the versatile dendrimer chemistry, the developed Fe3 O4 /Au NCPs may be differently functionalized, thereby providing a unique platform for diagnosis and therapy of different biological systems.

Research paper thumbnail of Targeted cancer theranostics using alpha-tocopheryl succinate-conjugated multifunctional dendrimer-entrapped gold nanoparticles

Biomaterials, Aug 1, 2014

Development of multifunctional theranostic nanoplatforms for targeted cancer imaging and therapy ... more Development of multifunctional theranostic nanoplatforms for targeted cancer imaging and therapy still remains a great challenge. Herein, we report the use of multifunctional dendrimer-entrapped gold nanoparticles (Au DENPs) covalently linked with a-tocopheryl succinate (a-TOS) as a platform for targeted cancer computed tomography (CT) imaging and therapy. In this study, amine-terminated poly(amidoamine) dendrimers of generation 5 (G5.NH 2) conjugated with fluorescein isothiocyanate (FI), polyethylene glycol (PEG)-modified a-TOS, and PEGylated folic acid (FA) were used as templates to synthesize Au DENPs, followed by acetylation of the remaining dendrimer terminal amines. The formed multifunctional Au DENPs were characterized via different techniques. We show that the Au DENPs conjugated with approximately 9.8 a-TOS molecules per dendrimer and with an Au core size of 3.3 nm are water-dispersible, and stable under different pH and temperature conditions and in different aqueous media. The FA modification onto the Au DENPs enables efficient targeting of the particles to cancer cells overexpressing FA receptors (FAR), and effective targeted CT imaging of the cancer cells in vitro and the xenografted tumor model in vivo. Likewise, the covalent conjugation of a-TOS does not compromise its therapeutic activity, instead significantly improves its water solubility. Importantly, thanks to the role of FA-directed targeting, the formed multifunctional Au DENPs are able to exert the specific therapeutic efficacy of a-TOS to the FAR-overexpressing cancer cells in vitro and the xenografted tumor model in vivo. The developed multifunctional Au DENPs may hold a great promise to be used as a unique theranostic nanoplatform for targeted CT imaging and therapy of different types of cancer.

Research paper thumbnail of Targeted CT/MR dual mode imaging of tumors using multifunctional dendrimer-entrapped gold nanoparticles

Biomaterials, Jul 1, 2013

We report the synthesis and characterization of folic acid (FA)-modified multifunctional dendrime... more We report the synthesis and characterization of folic acid (FA)-modified multifunctional dendrimer-entrapped gold nanoparticles (Au DENPs) loaded with gadolinium (Gd) for targeted dual mode computed tomography (CT)/magnetic resonance (MR) imaging of tumors. In this work, amine-terminated generation 5 poly(amidoamine) dendrimers (G5.NH2) modified with Gd(III) chelator, polyethylene glycol (PEG) monomethyl ether, and PEGylated FA were used as templates to entrap gold nanoparticles (AuNPs). Further chelation of Gd(III) ions and acetylation of the remaining dendrimer terminal amines led to the formation of multifunctional FA-targeted Au DENPs loaded with Gd(III) (Gd-Au DENPs-FA). The formed Gd-Au DENPs-FA probes were characterized via different techniques. We show that the Gd-Au DENPs-FA probes with an Au NP core size of 4.0 nm are water dispersible, stable under different pH and temperature conditions, and cytocompatible in the given concentration range. With the co-existence of AuNPs and Gd(III) ions within the single multifunctional particles, Gd-Au DENPs-FA displayed high X-ray attenuation intensity and reasonable r1 relaxivity. These properties of the particles enabled them to be used as dual mode nanoprobes for targeted CT/MR imaging of cancer cells in vitro and xenograft tumor model in vivo via FA receptor-mediated active targeting pathway. The strategy to design multifunctional nanoprobes using the versatile dendrimer nanotechnology may be extended to design various dual mode or multimode imaging agents for accurate diagnosis of different types of cancer.

Research paper thumbnail of Multifunctional dendrimer-entrapped gold nanoparticles for dual mode CT/MR imaging applications

Biomaterials, Feb 1, 2013

We report the synthesis, characterization, and utilization of gadolium-loaded dendrimer-entrapped... more We report the synthesis, characterization, and utilization of gadolium-loaded dendrimer-entrapped gold nanoparticles (GdeAu DENPs) for dual mode computed tomography (CT)/magnetic resonance (MR) imaging applications. In this study, amine-terminated generation five poly(amidoamine) dendrimers (G5.NH 2) modified with gadolinium (Gd) chelator and polyethylene glycol (PEG) monomethyl ether were used as templates to synthesize gold nanoparticles (AuNPs). Followed by sequential chelation of Gd(III) and acetylation of the remaining dendrimer terminal amine groups, multifunctional GdeAu DENPs were formed. The formed GdeAu DENPs were characterized via different techniques. We show that the formed GdeAu DENPs are colloidally stable and non-cytotoxic at an Au concentration up to 50 mM. With the coexistence of two radiodense imaging elements of AuNPs and Gd(III) within one NP system, the formed GdeAu DENPs display both r 1 relaxivity for MR imaging mode and X-ray attenuation property for CT imaging mode, which enables CT/MR dual mode imaging of the heart, liver, kidney, and bladder of rat or mouse within a time frame of 45 min. Furthermore, in vivo biodistribution studies reveal that the GdeAu DENPs have an extended blood circulation time and can be cleared from the major organs within 24 h. The strategy to use facile dendrimer technology to design dual mode contrast agents may be extended to prepare multifunctional platforms for targeted multimode molecular imaging of various biological systems.

Research paper thumbnail of Facile Hydrothermal Synthesis and Surface Functionalization of Polyethyleneimine-Coated Iron Oxide Nanoparticles for Biomedical Applications

ACS Applied Materials & Interfaces, Feb 19, 2013

We report the facile hydrothermal synthesis and surface functionalization of branched polyethylen... more We report the facile hydrothermal synthesis and surface functionalization of branched polyethyleneimine (PEI)-coated iron oxide nanoparticles (Fe 3 O 4 −PEI NPs) for biomedical applications. In this study, Fe 3 O 4 −PEI NPs were synthesized via a one-pot hydrothermal method in the presence of PEI. The formed Fe 3 O 4 −PEI NPs with primary amine groups on the surface were able to be further functionalized with polyethylene glycol (PEG), acetic anhydride, and succinic anhydride, respectively. The formed pristine and functionalized Fe 3 O 4 −PEI NPs were characterized via different techniques. We showed that the sizes of the Fe 3 O 4 −PEI NPs were able to be controlled by varying the mass ratio of Fe(II) salt and PEI. In addition, the formed Fe 3 O 4 −PEI NPs with different surface functionalities had good water dispersibility, colloidal stability, and relatively high R 2 relaxivity (130− 160 1/(mM•s)). Cell viability assay data revealed that the surface PEGylation and acylation of Fe 3 O 4 −PEI NPs rendered them with good biocompatibility in the given concentration range, while the pristine aminated Fe 3 O 4 −PEI NPs started to display slight toxicity at the concentration of 50 μg/mL. Importantly, macrophage cellular uptake results demonstrated that both PEGylation and acetylation of Fe 3 O 4 −PEI NPs were able to significantly reduce the nonspecific macrophage uptake, likely rendering the particles with prolonged circulation time. With the proven hemocompatibility and rich amine conjugation chemistry, the Fe 3 O 4 − PEI NPs with different surface functionalities may be applied for various biomedical applications, especially for magnetic resonance imaging and therapy.

Research paper thumbnail of Low kilovoltage peak (kVp) with an adaptive statistical iterative reconstruction algorithm in computed tomography urography: evaluation of image quality and radiation dose

PubMed, 2016

Purpose: The purpose of this study was to evaluate the image quality and radiation dose in comput... more Purpose: The purpose of this study was to evaluate the image quality and radiation dose in computed tomography urography (CTU) images acquired with a low kilovoltage peak (kVp) in combination with an adaptive statistical iterative reconstruction (ASiR) algorithm. Methods: A total of 45 subjects (18 women, 27 men) who underwent CTU with kV assist software for automatic selection of the optimal kVp were included and divided into two groups (A and B) based on the kVp and image reconstruction algorithm: group A consisted of patients who underwent CTU with a 80 or 100 kVp and whose images were reconstructed with the 50% ASiR algorithm (n=32); group B consisted of patients who underwent CTU with a 120 kVp and whose images were reconstructed with the filtered back projection (FBP) algorithm (n=13). The images were separately reconstructed with volume rendering (VR) and maximum intensity projection (MIP). Finally, the image quality was evaluated using an image score, CT attenuation, image noise, the contrast-to-noise ratio (CNR) of the renal pelvis-to-abdominal visceral fat and the signal-to-noise ratio (SNR) of the renal pelvis. The radiation dose was assessed using volume CT dose index (CTDIvol), dose-length product (DLP) and effective dose (ED). Results: For groups A and B, the subjective image scores for the VR reconstruction images were 3.9±0.4 and 3.8±0.4, respectively, while those for the MIP reconstruction images were 3.8±0.4 and 3.6±0.6, respectively. No significant difference was found (p>0.05) between the two groups' image scores for either the VR or MIP reconstruction images. Additionally, the inter-reviewer image scores did not significantly differ (p>0.05). The mean attenuation of the bilateral renal pelvis in group A was significantly higher than that in group B (271.4±57.6 vs. 221.8±35.3 HU, p<0.05), whereas the image noise in group A was significantly lower than that in group B (7.9±2.1 vs. 10.5±2.3 HU, p<0.05). The CNR and SNR in group A were both significantly higher than those in group B (53.61±24.74 vs. 32.30±6.52 for CNR; 38.13±19.86 vs. 21.76±4.85 for SNR; all p<0.05). The CTDIvol, DLP and ED in group A were significantly lower than those in group B (9.26±2.77 vs. 16.19±5.60 mGy for CTDIvol; 368.86±119.38 vs. 674.38±239.37 mGy×cm-1 for DLP; 5.53±1.79 vs. 10.12±3.59 mSv for ED; all p<0.05). Conclusions: The low kVp CTU images with 50% ASiR reconstruction exhibit sufficient image quality and facilitate up to a 44% radiation dose reduction.

Research paper thumbnail of Arg-Gly-Asp-D-Phe-Lys peptide-modified PEGylated dendrimer-entrapped gold nanoparticles for targeted computed tomography imaging of breast carcinoma

Nanomedicine, Jul 1, 2015

To investigate cyclo (Arg-Gly-Asp-D-Phe-Lys) peptide (RGD)-modified PEGylated dendrimer-entrapped... more To investigate cyclo (Arg-Gly-Asp-D-Phe-Lys) peptide (RGD)-modified PEGylated dendrimer-entrapped gold nanoparticles (PEGylated Au DENPs-RGD) for targeted computed tomography (CT) imaging of breast carcinomas. Materials & methods: PEGylated Au DENPs-RGD were synthesized and characterized. Then, the PEGylated Au DENPs-RGD for targeted CT imaging were investigated using the MDA-MB-435 cell line, an integrin-rich breast carcinoma cells, and mice with MDA-MB-435 xenograft tumors. Finally, silver enhancement staining and integrin α v β 3 immunohistochemistry of the tumors were performed. Results: The synthesized PEGylated Au DENPs-RGD were spherical, water dispersible and biocompatible nanoprobes with a gold nanoparticle core size of 2.8 nm. Due to the presence of the Au nanoparticles, the PEGylated Au DENPs-RGD displayed a higher x-ray attenuation intensity than Omnipaque at the same Au or I concentrations. The conjugated RGD ligand can specifically identify and target overexpressed integrin receptors on MDA-MB-435 cells. After intravenous injection, these nanoprobes accumulated in the targeted area of mice with MDA-MB-435 xenograft tumors, which enabled the tumor to be detected by CT imaging. The histological results confirmed the imaging results. Conclusion: The PEGylated Au DENPs-RGD can be used as targeted nanoprobes with good biocompatibility for targeted CT imaging and diagnosis of integrin-positive tumors.

Research paper thumbnail of Dendrimer-entrapped gold nanoparticles as potential CT contrast agents for blood pool imaging

Nanoscale Research Letters, Mar 19, 2012

The purpose of this study was to evaluate dendrimer-entrapped gold nanoparticles [Au DENPs] as a ... more The purpose of this study was to evaluate dendrimer-entrapped gold nanoparticles [Au DENPs] as a molecular imaging [MI] probe for computed tomography [CT]. Au DENPs were prepared by complexing AuCl 4 ions with amine-terminated generation 5 poly(amidoamine) [G5.NH 2 ] dendrimers. Resulting particles were sized using transmission electron microscopy. Serial dilutions (0.001 to 0.1 M) of either Au DENPs or iohexol were scanned by CT in vitro. Based on these results, Au DENPs were injected into mice, either subcutaneously (10 μL, 0.007 to 0.02 M) or intravenously (300 μL, 0.2 M), after which the mice were imaged by micro-CT or a standard mammography unit. Au DENPs prepared using G5.NH 2 dendrimers as templates are quite uniform and have a size range of 2 to 4 nm. At Au concentrations above 0.01 M, the CT value of Au DENPs was higher than that of iohexol. A 10-μL subcutaneous dose of Au DENPs with [Au] ≥ 0.009 M could be detected by micro-CT. The vascular system could be imaged 5 and 20 min after injection of Au DENPs into the tail vein, and the urinary system could be imaged after 60 min. At comparable time points, the vascular system could not be imaged using iohexol, and the urinary system was imaged only indistinctly. Findings from this study suggested that Au DENPs prepared using G5.NH 2 dendrimers as templates have good X-ray attenuation and a substantial circulation time. As their abundant surface amine groups have the ability to bind to a range of biological molecules, Au DENPs have the potential to be a useful MI probe for CT.

Research paper thumbnail of PEGylated polyethylenimine-entrapped gold nanoparticles modified with folic acid for targeted tumor CT imaging

Colloids and Surfaces B: Biointerfaces, Apr 1, 2016

Development of various cost-effective contrast agents for targeted tumor computed tomography (CT)... more Development of various cost-effective contrast agents for targeted tumor computed tomography (CT) imaging still remains a great challenge. Herein, we present a facile approach to forming folic acid (FA)-targeted multifunctional gold nanoparticles (AuNPs) using cost-effective branched polyethylenimine (PEI) modified with polyethylene glycol (PEG) as a template for tumor CT imaging applications. In this work, PEI sequentially modified with PEG monomethyl ether, FA-linked PEG, and fluorescein isothiocyanate was used as a template to synthesize AuNPs, followed by transformation of the remaining PEI surface amines to acetamides. The formed FA-targeted PEI-entrapped AuNPs (FA-Au PENPs) were fully characterized. We show that the formed FA-Au PENPs with an Au core size of 2.1nm are water soluble, colloidally stable, and non-cytotoxic in a given concentration range. Flow cytometry and confocal microscopy data reveal that the FA-Au PENPs are able to target cancer cells overexpressing FA receptors (FAR). Importantly, the developed FA-Au PENPs can be used as a nanoprobe for targeted CT imaging of FAR-expressing cancer cells in vitro and the xenografted tumor model in vivo. With the demonstrated biocompatibility by organ biodistribution and histological studies, the designed FA-Au PENPs may hold great promise to be used as a nanoprobe for CT imaging of different FAR-overexpressing tumors.

Research paper thumbnail of Facile assembly of Fe3O4@Au nanocomposite particles for dual mode magnetic resonance and computed tomography imaging applications

Journal of Materials Chemistry, 2012

Research paper thumbnail of X-ray Attenuation Property of Dendrimer-Entrapped Gold Nanoparticles

Journal of Physical Chemistry C, Dec 15, 2009

... 19. Kumar, S.; Harrison, N.; Richards-Kortum, R.; Sokolov, K. Nano Lett. 2007, 7, 1338 ...

Research paper thumbnail of Differentiation between adrenal adenomas and nonadenomas using dynamic contrast-enhanced computed tomography

OncoTargets and Therapy, Nov 1, 2016

This study was performed to evaluate the findings including the time density curve (TD curve), th... more This study was performed to evaluate the findings including the time density curve (TD curve), the relative percentage of enhancement washout (Washr) and the absolute percentage of enhancement washout (Washa) at dynamic contrast-enhanced computed tomography (DCE-CT) in 70 patients with 79 adrenal masses (including 44 adenomas and 35 nonadenomas) confirmed histopathologically and/or clinically. The results demonstrated that the TD curves of adrenal masses were classified into 5 types, and the type distribution of the TD curves was significantly different between adenomas and nonadenomas. Types A and C were characteristic of adenomas, whereas types B, D and E were features of nonadenomas. The sensitivity, specificity and accuracy for the diagnosis of adenoma based on the TD curves were 93%, 80% and 87%, respectively. Furthermore, when myelolipomas were excluded, the specificity and accuracy for adenoma were 90% and 92%, respectively. The Washr and the Washa values for the adenomas were higher than those for the nonadenomas. The diagnostic efficiency for adenoma was highest at 7-min delay time at DCE-CT; Washr was more efficient than Washa. Washr 34% and Washa 43% were both suggestive of adenomas and, on the contrary, suspicious of nonadenomas. The sensitivity, specificity and accuracy for the diagnosis of adenoma were 84%, 77% and 81%, respectively. When myelolipomas were precluded, the diagnostic specificity and accuracy were 87% and 85%, respectively. Therefore, DCE-CT aids in characterization of adrenal tumors, especially for lipid-poor adenomas which can be correctly categorized on the basis of TD curve combined with the percentage of enhancement washout.

Research paper thumbnail of Facile hydrothermal synthesis of low generation dendrimer-stabilized gold nanoparticles for in vivo computed tomography imaging applications

Research paper thumbnail of Magnetic resonance imaging of glioma with novel APTS-coated superparamagnetic iron oxide nanoparticles

Nanoscale Research Letters, Jun 15, 2014

We report in vitro and in vivo magnetic resonance (MR) imaging of C6 glioma cells with a novel ac... more We report in vitro and in vivo magnetic resonance (MR) imaging of C6 glioma cells with a novel acetylated 3-aminopropyltrimethoxysilane (APTS)-coated iron oxide nanoparticles (Fe 3 O 4 NPs). In the present study, APTS-coated Fe 3 O 4 NPs were formed via a one-step hydrothermal approach and then chemically modified with acetic anhydride to generate surface charge-neutralized NPs. Prussian blue staining and transmission electron microscopy (TEM) data showed that acetylated APTS-coated Fe 3 O 4 NPs can be taken up by cells. Combined morphological observation, cell viability, and flow cytometric analysis of the cell cycle indicated that the acetylated APTS-coated Fe 3 O 4 NPs did not significantly affect cell morphology, viability, or cell cycle, indicating their good biocompatibility. Finally, the acetylated APTS-coated Fe 3 O 4 nanoparticles were used in magnetic resonance imaging of C6 glioma. Our results showed that the developed acetylated APTS-coated Fe 3 O 4 NPs can be used as an effective labeling agent to detect C6 glioma cells in vitro and in vivo for MR imaging. The results from the present study indicate that the developed acetylated APTS-coated Fe 3 O 4 NPs have a potential application in MR imaging.

Research paper thumbnail of Synthesis of PEGylated low generation dendrimer-entrapped gold nanoparticles for CT imaging applications