Vikas Nandwana | Northwestern University (original) (raw)

Papers by Vikas Nandwana

Journal of Physical Chemistry C, Jul 2, 2009

In this research, for the first time the synergistic effect of Ag nanoparticle to enhance the pho... more In this research, for the first time the synergistic effect of Ag nanoparticle to enhance the photocatalytic activity of nanocatalyst Fe 3 O 4 @CeO 2 (CF) was demonstrated. To synthesis Fe 3 O 4 @CeO 2 /Ag (CFA) after preparation of magnetic Fe 3 O 4 nanoparticle, cerium dioxide was supported on the prepared Fe 3 O 4. To improve the photocatalytic activity of nanocomposite (CF), it was decorated by an optimized concentration of Ag (NO 3) with the reduction of Ag + cations by NaBH 4 solution. FT-IR, EDX, SEM, and XRD analysis were used to characterization of the structure and morphology of the synthesized compounds. The photocatalytic activity of prepared nanocomposite was investigated by photodegradation of methylene blue (MB) in aqueous solution under UV light irradiation. The results were shown that the synergistic effect of Ag particle has increased the photocatalytic activity of the CFA about 2 times higher than the CF nanocomposite. The mechanism investigation determined that the radicals O 2 •− and OH • are the main species in the photocatalysis process by CFA.

42nd Society for Biomaterials Annual Meeting and Exposition 2019: The Pinnacle of Biomaterials Innovation and Excellence, 2019

Magnetic nanostructures (MNS) have a wide range of biological applications due to their biocompat... more Magnetic nanostructures (MNS) have a wide range of biological applications due to their biocompatibility, superparamagnetic properties, and customizable composition that includes iron oxide (Fe 3 O 4), Zn 2+ , and Mn 2+. However, several challenges to the biomedical usage of MNS must still be addressed, such as formulation stability, inability to encapsulate therapeutic payloads, and variable clearance rates in vivo. Here, we enhance the utility of MNS during controlled delivery applications via encapsulation within polymeric bicontinuous nanospheres (BCNs) composed of poly(ethylene glycol)-block-poly(propylene sulfide) (PEG-b-PPS) copolymers. PEG-b-PPS BCNs have demonstrated versatile encapsulation and delivery capabilities for both hydrophilic and hydrophobic payloads due to their unique and highly organized cubic phase nanoarchitecture. MNS-embedded BCNs (MBCNs) were thus coloaded with physicochemically diverse molecular payloads using the technique of flash nanoprecipitation and characterized in terms of their structure and in vivo biodistribution following intravenous administration. Retention of the internal aqueous channels and cubic architecture of MBCNs were verified using cryogenic transmission electron microscopy and small-angle X-ray scattering, respectively. MBCNs demonstrated improvement in magnetic resonance imaging (MRI) contrast enhancement (r 2 relaxivity) as compared to free MNS, which in combination with scanning transmission electron microscopy and energy-dispersive X-ray spectroscopy evidenced the clustering and continued access to water of MNS following encapsulation. Furthermore, MBCNs were found to be noncytotoxic and able to deliver their hydrophilic and hydrophobic small-molecule payloads both in vitro and in vivo. Finally, the oxidation sensitivity of the hydrophobic PPS block allowed MBCNs to undergo a unique, triggerable transition in morphology into MNS-bearing micellar nanocarriers. In summary, MBCNs are an attractive platform for the delivery of molecular and nanoscale payloads for diverse on-demand and sustained drug delivery applications.

ACS ES&T water, May 10, 2023

ACS applied nano materials, Mar 26, 2018

We report a novel synthesis of Fe 3 O 4 /MoS 2 zero-dimensional (0D)/two-dimensional (2D) nanocom... more We report a novel synthesis of Fe 3 O 4 /MoS 2 zero-dimensional (0D)/two-dimensional (2D) nanocomposites. When bulk MoS 2 is exfoliated in the presence of thiolfunctionalized Fe 3 O 4 nanoparticles in water, the latter anchor on the exfoliated MoS 2 nanosheets because of thiol affinity toward MoS 2 , resulting in the Fe 3 O 4 /MoS 2 nanocomposites. The one-pot reaction, room temperature processing, and use of aqueous solvents make the synthesis process facile and ecofriendly. Because of the unique 0D/2D morphology, Fe 3 O 4 /MoS 2 nanocomposites show significantly higher peroxidase-like catalytic activity compared to Fe 3 O 4 nanoparticles or MoS 2 nanosheets alone. The enhanced catalytic activity has been used to detect glucose levels down to 2.4 μM in absorbance measurements. Application toward noninvasive point-ofcare glucose diagnostics has been explored by developing paper-based "dip and use" test strips that show colorimetric response in the presence of glucose. To achieve this, Fe 3 O 4 /MoS 2 nanocomposites along with other active sensing elements are printed onto paper via a desktop inkjet printer and cut into strips. When dipped into solutions of various glucose concentrations, the test strips allow colorimetric detection of glucose concentrations in a qualitative and quantitative manner. To demonstrate practical usage, we have shown that the Fe 3 O 4 /MoS 2 nanocomposite-based glucose test strips are sufficient to distinguish between normal (healthy) and higher (diabetic) glucose concentrations with the naked eye. Because of the simple and ecofriendly preparation and sensing efficacy with low limit of detection, Fe 3 O 4 /MoS 2 nanocomposites show promise in noninvasive point-of-care medical diagnostics.

Journal of Physics D, Jan 19, 2007

Atomic interdiffusion between FePt and Fe 3 O 4 nanoparticles in annealed FePt-based nanocomposit... more Atomic interdiffusion between FePt and Fe 3 O 4 nanoparticles in annealed FePt-based nanocomposite magnets has been studied by means of structural and magnetic characterizations. The results show that the Fe 3 Pt phase is formed during the annealing only when the mass ratio x of Fe 3 O 4 /FePt is larger than 1/20. When x 1/20, only FePt single phase is formed. It is interesting to find that the coercivity of the annealed samples increases with a small addition of Fe 3 O 4 before the formation of the Fe 3 Pt phase. This magnetic hardening behaviour indicates that the composition of the FePt phase can be further adjusted via the post annealing process. The characteristic of recoil loops and Henkel plots also give evidence for the transition from single-phase FePt magnets to nanocomposite magnets with the addition of Fe 3 O 4 .

The effect of isolation on the phase transition temperature of FePt nanoparticles has been studie... more The effect of isolation on the phase transition temperature of FePt nanoparticles has been studied systematically by thermal, magnetic and structural characterizations and analyses. Isolated monodisperse L10 FePt nanoparticles embedded in carbon matrix were obtained by adding enough surfactants after chemical synthesis and by post-annealing during which the surfactant decomposed into carbon. It was found that the Al to L10

Chemistry of Materials, Dec 22, 2007

Bimagnetic FePt/CoFe 2 O 4 nanoparticles having a bricklike morphology were synthesized by growin... more Bimagnetic FePt/CoFe 2 O 4 nanoparticles having a bricklike morphology were synthesized by growing a soft magnetic CoFe 2 O 4 phase on FePt cubic nanoparticle seeds. The size of the soft phase could be controlled by tuning the material ratio of the FePt seeds to the CoFe 2 O 4 component. To obtain magnetic hardening, the as-synthesized bricklike nanoparticles were annealed at elevated temperatures under a reductive atmosphere to convert the disordered face-centered cubic FePt phase into the ordered L1 0 phase having high magnetic anisotropy. When the particles were annealed, a gradual change was observed in morphology from bricklike particles to spherical polycrystalline nanocomposite particles because of diffusion. Meanwhile, the magnetic energy density was enhanced as a result of the exchange coupling between the hard and soft phases. The enhancement was dependent on the ratio of the volumes of the soft phase and the hard phase.

Microscopy and Microanalysis

Alzheimer's & Dementia: Translational Research & Clinical Interventions

IntroductionAmyloid‐beta oligomers (AβOs) accumulate in Alzheimer's disease and may instigate... more IntroductionAmyloid‐beta oligomers (AβOs) accumulate in Alzheimer's disease and may instigate neuronal pathology and cognitive impairment. We examined the ability of a new probe for molecular magnetic resonance imaging (MRI) to detect AβOs in vivo, and we tested the behavioral impact of AβOs injected in rabbits, a species with an amino acid sequence that is nearly identical to the human sequence.MethodsIntracerebroventricular (ICV) injection with stabilized AβOs was performed. Rabbits were probed for AβO accumulation using ACUMNS (an AβO‐selective antibody [ACU193] coupled to magnetic nanostructures). Immunohistochemistry was used to verify AβO presence. Cognitive impairment was evaluated using object location and object recognition memory tests and trace eyeblink conditioning.ResultsAβOs in the entorhinal cortex of ICV‐injected animals were detected by MRI and confirmed by immunohistochemistry. Injections of AβOs also impaired hippocampal‐dependent, but not hippocampal‐independ...

Materials Science and Engineering: C, 2021

Imaging of immune cells has wide implications in understanding disease progression and staging. W... more Imaging of immune cells has wide implications in understanding disease progression and staging. While optical imaging is limited in penetration depth due to light properties, magnetic resonance (MR) imaging provides a more powerful tool for the imaging of deep tissues where immune cells reside. Due to poor MR signal to noise ratio, tracking of such cells typically requires contrast agents. This report presents an in-depth physical characterization and application of archaeal magnetoferritin for MR imaging of macrophages - an important component of the innate immune system that is the first line of defense and first responder in acute inflammation. Magnetoferritin is synthesized by loading iron in apoferritin in anaerobic condition at 65 °C. The loading method results in one order of magnitude enhancement of r1 and r2 relaxivities compared to standard ferritin synthesized by aerobic loading of iron at room temperature. Detailed characterizations of the magnetoferritin revealed a crystalline core structure that is distinct from previously reported ones indicating magnetite form. The magnetite core is more stable in the presence of reducing agents and has higher peroxidase-like activities compared to the core in standard loading. Co-incubation of macrophage cells with magnetoferritin in-vitro shows significantly higher enhancement in T2-MRI contrast of the immune cells compared to standard ferritin.

Industrial & Engineering Chemistry Research, 2020

Oil spills have huge and immediate economically, socially, and environmentally adverse impacts. C... more Oil spills have huge and immediate economically, socially, and environmentally adverse impacts. Current methods to remediate oil spills do not provide a sustainable solution, in terms of cost, ease of deployment, and further impact on the environment. Here we report an oil spill remediation solution in form of an oleophilic, hydrophobic, and magnetic (OHM) sponge that is economical, efficient, and ecofriendly; thereby promising a potentially industry-adaptable approach. The OHM sponge can not only selectively remove the oil from oil/water interface but also recover the oil by a simple squeezing process. Furthermore, the OHM sponge can be reused for many cycles. The OHM sponge works effectively in diverse and extreme aquatic conditions (pH, salinity) and can absorb a variety of oils and oil-based compounds. The selective absorption/desorption, recovery, high absorption capacity, and reusability under one platform open new prospects for potentially sustainable water and environmental remediation applications.

Advanced NanoBiomed Research, 2021

With a significant proportion of the global population growing older (>60 years), the low succ... more With a significant proportion of the global population growing older (>60 years), the low success rates of current diagnoses for early neurodegeneration signs are disappointing. Early detection of Alzheimer's disease (AD) can improve acclimatization and quality of life for patients in their later years. Endogenous proteins, such as the most abundant secreted protein in cerebrospinal fluid, lipocalin‐type prostaglandin d synthase (L‐PGDS), can bind the early toxic oligomers of amyloid β (Aβ) peptides implicated in AD and prevent their aggregation. Herein, the utility of L‐PGDS for detection of amyloids is demonstrated. L‐PGDS is conjugated with different iron‐oxide magnetic nanoparticles for contrast‐enhanced visualization using magnetic resonance imaging (MRI). These conjugates inhibit amyloid aggregation in vitro and improve viability in neuronal cells incubated with amyloid fibrils, showing a potential neuroprotective function. L‐PGDS‐ferritin conjugates, when administered ...

Microscopy and Microanalysis, 2021

Improvements have been made in the diagnosis of Alzheimer’s disease (AD), manifesting mostly in t... more Improvements have been made in the diagnosis of Alzheimer’s disease (AD), manifesting mostly in the development of in vivo imaging methods that allow for the detection of pathological changes in AD by MRI and PET scans. Many of these imaging methods, however, use agents that probe amyloid fibrils and plaques - species that do not correlate well with disease progression and are not present at the earliest stages of the disease. Amyloid β oligomers (AβOs), rather, are now widely accepted as the Aβ species most germane to AD onset and progression. Here we report evidence further supporting the role of AβOs as pathological instigators of AD and introduce promising anti-AβO diagnostic probes capable of distinguishing the 5xFAD mouse model from wild type mice by PET and MRI. In a developmental study, Aβ oligomers in 5xFAD mice were found to appear at 3 months of age, just prior to the onset of memory dysfunction, and spread as memory worsened. The increase of AβOs is prominent in the subi...

Biosensors and Bioelectronics, 2021

Elsevier has created a COVID-19 resource centre with free information in English and Mandarin on ... more Elsevier has created a COVID-19 resource centre with free information in English and Mandarin on the novel coronavirus COVID-19. The COVID-19 resource centre is hosted on Elsevier Connect, the company's public news and information website. Elsevier hereby grants permission to make all its COVID-19-related research that is available on the COVID-19 resource centre-including this research content-immediately available in PubMed Central and other publicly funded repositories, such as the WHO COVID database with rights for unrestricted research re-use and analyses in any form or by any means with acknowledgement of the original source. These permissions are granted for free by Elsevier for as long as the COVID-19 resource centre remains active.

Microscopy and Microanalysis, 2020

ACS Applied Materials & Interfaces, 2020

Endogenous brain proteins can recognize the toxic oligomers of amyloid-β (Aβ) peptides implicated... more Endogenous brain proteins can recognize the toxic oligomers of amyloid-β (Aβ) peptides implicated in Alzheimer’s disease (AD) and interact with them to prevent their aggregation. Lipocalin-type Prostaglandin D Synthase (L-PGDS) is a major Aβ-chaperone protein in the human cerebrospinal fluid. Here we demonstrate that L-PGDS detects amyloids in diseased mouse brain. Conjugation of L-PGDS with magnetic nanoparticles enhanced the contrast for magnetic resonance imaging. We conjugated the L-PGDS protein with ferritin nanocages to detect amyloids in the AD mouse model brain. We show here that the conjugates administered through intraventricular injections co-localize with amyloids in the mouse brain. These conjugates can target the brain regions through non-invasive intranasal administration, as shown in healthy mice. These conjugates can inhibit the aggregation of amyloids in vitro and show potential neuroprotective function by breaking down the mature amyloid fibrils.

ACS Biomaterials Science & Engineering, 2019

Here we report design of a smart nanoconstruct that can be used as a multimodal theranostic platf... more Here we report design of a smart nanoconstruct that can be used as a multimodal theranostic platform for imaging and therapy applications. Decorated with two sizes of magnetic nanostructures (MNS) on thermoresponsive nanosized hydrogel (NG), the NG-MNS nanoconstruct shows dual-mode contrast enhancement ability in MRI and thermo-chemo therapeutic ability under an RF field. Because of the unique design where all MNS are at the exterior of the nanoconstruct, no compromise in the physical properties of MNS and their effect on contrast enhancement and thermal activation has been observed. In a series of in vitro analyses in human breast adenocarcinoma (MDA-MB-231) cells, we validate that NG-MNS show dual-mode MR imaging capability with a higher signal/noise ratio than in clinically approved dual-mode contrast agents as well as enhanced therapeutic efficacy compared to previously reported hydrogel-based nanocarriers and free drug systems.

Journal of Materials Chemistry B, 2018

A novel magnetic nanostructures (MNS) stabilized lipid nanoconstruct is reported that shows super... more A novel magnetic nanostructures (MNS) stabilized lipid nanoconstruct is reported that shows superior structural stability and theranostic functionality than conventional lipid based nanocarriers.