Animesh Samanta | National University of Singapore (original) (raw)

Papers by Animesh Samanta

Journal of Materials Chemistry B, 2022

A new pentacyclic pyridinium-based mitochondria-specific fluorescent probe, PM-S, exhibited a spe... more A new pentacyclic pyridinium-based mitochondria-specific fluorescent probe, PM-S, exhibited a specific turn-on fluorescence response towards hypochlorous acid and enabled imaging of oxidative stress in mitochondria through Nox2 activation.

Fluorescent Chemosensors

Fluorescent chemosensors have been widely applied in many diverse fields such as biology, physiol... more Fluorescent chemosensors have been widely applied in many diverse fields such as biology, physiology, pharmacology, and environmental sciences. The interdisciplinary nature of chemosensor research has continued to grow over the last 25 years to meet the increasing needs of monitoring our environment and health. More recently, a large range of fluorescent chemosensors have been established for the detection of biologically and/or environmentally important species, and are increasingly being used to solve biological problems. The use of these molecules as imaging probes to diagnose and treat disease is gaining momentum with clear future applications. This book will bring together world-leading experts to describe the current state of play in the field and introduce the cutting-edge research and possible future directions into fluorescent chemosensors design. Chapters focus on the basic principles involved in the design of chemosensors for specific analytes, problems, and challenges in...

Scientific Reports, 2019

Alzheimer’s disease (AD) is now clinically considered as a chronic inflammation-based neurodegene... more Alzheimer’s disease (AD) is now clinically considered as a chronic inflammation-based neurodegenerative disease. The CDnir7 probe was previously developed as an optical imaging probe to target macrophages in order to image mouse inflammation using in vivo optical imaging modalities such as In Vivo imaging system (IVIS) and fluorescent molecular tomography (FMT). Here, we demonstrate the application of CDnir7 in AD mouse brain imaging via multispectral optoacoustic tomography (MSOT). Longitudinal MSOT imaging of CDnir7 showed higher CDnir7 localization in AD mouse cerebral cortex compared to that of normal mice. MSOT signals of CDnir7 localization in mouse brain were verified by ex vivo near-infrared (NIR) imaging and immunohistochemistry. Histological evaluation showed strong CDnir7 staining in AD cerebral cortex, hippocampus, basal ganglia and thalamus area. Based on the supporting evidence, CDnir7 has great potential as a molecular imaging probe for AD brain imaging.

Chemistry - A European Journal, 2018

Organelle targeted photosensitizers (PSs) having luminescence properties are potential theranosti... more Organelle targeted photosensitizers (PSs) having luminescence properties are potential theranostic agents for simultaneous luminescence imaging and photodynamic therapy. Herein, we report a water soluble luminescent cyclometalated Ir(III) complex, Ir-Bp-Ly as lysosome targeted theranostic probe. Ir-Bp-Ly exhibits exceptional photophysical properties of good triplet state quantum yield (0.90), singlet oxygen generation quantum yield (0.71 at pH 4) and long lifetime (1.47 µs). Interestingly, Ir-Bp-Ly localized mostly in the lysosome because of the presence of morpholine units, suggesting its potential as a lyso-tracker. Ir-Bp-Ly displayed notable PDT effect in C6 glioma cells, as these PS efficiently generated ROS owing to the close proximity energy levels between triplet energy states of Ir-Bp-Ly and molecular oxygen (3 O2). The mechanism of cell death was studied through caspase-3/7 and flow cytometry analysis that clearly established the apoptotic pathway.

Sensors and Actuators B: Chemical, 2021

Chemical Communications

A unique highly water-soluble ICT-based fluorescent probe is developed for efficient detection an... more A unique highly water-soluble ICT-based fluorescent probe is developed for efficient detection and discrimination of reactive monocarbonyl formaldehyde (FA) from dicarbonyl methylglyoxal (MGO)/glyoxal (GO) by modulating the ICT process that...

Chemical Science

A modified Vilsmeier–Haack reaction resulted in the synthesis of a pyrylium based turn-on fluores... more A modified Vilsmeier–Haack reaction resulted in the synthesis of a pyrylium based turn-on fluorescent pH probe. The probe can monitor minute acidification and dynamic pH variation in cells during apoptosis with therapeutic chemo drugs.

Journal of Photochemistry and Photobiology B: Biology

Chemistry - A European Journal

Advanced Healthcare Materials

Journal of the American Chemical Society

Tumor initiating cells (TIC) are resistant to conventional anti-cancer therapy and associated wit... more Tumor initiating cells (TIC) are resistant to conventional anti-cancer therapy and associated with metastasis and relapse in cancer. Although various TIC markers and their antibodies have been proposed, it is limited to use of antibodies for in vivo imaging or treatment of TIC. In this study, we discovered heme oxygenase 2 (HMOX2) as a novel biomarker for TIC and developed a selective small molecule probe TiNIR (Tumor Initiating cell probe with Near Infra-Red). TiNIR detects and enriches the functionally active TIC in human lung tumors, and through photoacoustic proper-ty, TiNIR also visualizes lung TIC in the patient-derived xenograft (PDX) model. Furthermore, we demonstrate that TiNIR inhibits tumor growth by blocking the function of HMOX2, resulting in significantly increased survival rates of the cancer model mice. The novel therapeutic target HMOX2 and its fluorescent ligand TiNIR will open a new path for molecular level of lung TIC diagnosis and treatment.

Chem

Elastic fibers are present in a variety of tissues and are responsible for their resilience. Unti... more Elastic fibers are present in a variety of tissues and are responsible for their resilience. Until now, no optical contrast agent in the near-infrared (NIR) wavelength range of 700-900 nm has been reported for the imaging of elastic fibers. Here, we report the discovery of a NIR zwitterionic elastin probe ElaNIR (elastin NIR) through fluorescent-image-based screening. The probe was successfully applied for in vitro, ex vivo, and in vivo imaging by various imaging modalities. Age-related elastin differences shown by in vivo fluorescent and photoacoustic imaging indicated that ElaNIR can be a potentially convenient tool for uncovering changes of elastin in live models.

Advanced materials (Deerfield Beach, Fla.), Jan 10, 2017

Although multifunctional upconversion imaging probes have recently attracted considerable interes... more Although multifunctional upconversion imaging probes have recently attracted considerable interest in biomedical research, there are currently few methods for stabilizing these luminescent nanoprobes with oligonucleotides in biological systems. Herein, a method to robustly disperse upconversion nanoprobes in physiological buffers based on rational design and synthesis of nanoconjugates comprising hairpin-DNA-modified gold nanoparticles is presented. This approach imparts the upconversion nanoprobes with excellent biocompatibility and circumvents the problem of particle agglomeration. By combining single-band anti-Stokes near-infrared emission and the photothermal effect mediated by the coupling of gold to upconversion nanoparticles, a simple, versatile nanoparticulate system for simultaneous deep-tissue imaging and drug molecule release in vivo is demonstrated.

Angewandte Chemie (International ed. in English), Jan 15, 2017

Drug toxicity is a long-standing concern of modern medicine. A typical anti-pain/fever drug parac... more Drug toxicity is a long-standing concern of modern medicine. A typical anti-pain/fever drug paracetamol often causes hepatotoxicity due to peroxynitrite ONOO(-) . Conventional blood tests fail to offer real-time unambiguous visualization of such hepatotoxicity in vivo. Here we report a luminescent approach to evaluate acute hepatotoxicity in vivo by chromophore-conjugated upconversion nanoparticles. Upon injection, these nanoprobes mainly accumulate in the liver and the luminescence of nanoparticles remains suppressed owing to energy transfer to the chromophore. ONOO(-) can readily bleach the chromophore and thus recover the luminescence, the presence of ONOO(-) in the liver leads to fast restoring of the near-infrared emission. Taking advantages of the high tissue-penetration capability of near-infrared excitation/emission, these nanoprobes achieve real-time monitoring of hepatotoxicity in living animals, thereby providing a convenient screening strategy for assessing hepatotoxicit...

Oncotarget, 2014

Early detection of gastric cancers saves lives, but remains a diagnostic challenge. In this study... more Early detection of gastric cancers saves lives, but remains a diagnostic challenge. In this study, we aimed to identify cell-surface biomarkers of early gastric cancer. We hypothesized that a subset of plasma membrane proteins induced by the Helicobacter pylori oncoprotein CagA will be retained in early gastric cancers through non-oncogene addiction. An inducible system for expression of CagA was used to identify differentially upregulated membrane protein transcripts in vitro. The top hits were then analyzed in gene expression datasets comparing transcriptome of gastric cancer with normal tissue, to focus on markers retained in cancer. Among the transcripts enriched upon CagA induction in vitro, a significant elevation of CEACAM6 was noted in gene expression datasets of gastric cancer. We used quantitative digital immunohistochemistry to measure CEACAM6 protein levels in tissue microarrays of gastric cancer. We demonstrate an increase in CEACAM6 in early gastric cancers, when compared to matched normal tissue, with an AUC of 0.83 for diagnostic validity. Finally, we show that a fluorescently conjugated CEACAM6 antibody binds avidly to freshly resected gastric cancer xenograft samples and can be detected by endoscopy in real time. Together, these results suggest that CEACAM6 upregulation is a cell surface response to H. pylori CagA, and is retained in early gastric cancers. They highlight a novel link between CEACAM6 expression and CagA in gastric cancer, and suggest CEACAM6 to be a promising biomarker to aid with the fluorescent endoscopic diagnosis of early neoplastic lesions in the stomach.

Advanced Functional Materials, 2015

Hydrogen sulfide (H2S) has been recognized as one of most important gaseous signaling molecules m... more Hydrogen sulfide (H2S) has been recognized as one of most important gaseous signaling molecules mediated by a variety of physiological and pathological processes. Yet, its functions remain largely elusive due to the lack of potent monitoring methods. Hereby this issue is addressed with a powerful new platform—dye-assembled upconversion nanoparticles (UCNPs). A series of chromophores with different absorption bands and fast responses towards H2S is combined with UCNPs and results in a library of H2S sensors with responsive emission signals ranging from the visible to the near-infrared (NIR) region. These nanoprobes demonstrate highly selective and rapid responses to H2S in vitro and in cells. Furthermore, H2S levels in blood can be detected using the developed nanoprobes. Hence the reported H2S sensing platform can serve as a powerful diagnostic tool to research H2S functions and to investigate H2S-related diseases.

Advanced Functional Materials, 2016

American Journal of Nuclear Medicine and Molecular Imaging, 2014

Herein, we report fifty four membered, a new set of novel NIR Raman reporters and CyRLA-572 has b... more Herein, we report fifty four membered, a new set of novel NIR Raman reporters and CyRLA-572 has been selected to be the best among them considering the signal intensity and stability. This new reporter molecule is an excellent partner with our in house Raman reporters (Cy7LA and Cy7.5LA). These three NIR Raman reporters are adsorbed on the gold nanoparticles to obtain their corresponding unique SERS fingerprints in which three individual characteristic peaks are capable to multiplex among them. These multiplexed Raman reporters are applied to develop biocompatible and specific targeting SERS nanotags after tagging with specific antibodies. These multiplex targeted SERS nanotags are applied to detect three targeting receptors in differentiated mouse embryonic stem cells (mESCs) consisting three germ layers such as ectoderm, mesoderm and endoderm. After successful recognition of cells by SERS techniques, we detect simultaneously three germ layers in teratoma which is a monster tumor formed from mESC cells in animal xenograft model.

Angewandte Chemie (International ed. in English), Jan 25, 2016

A diradical approach to obtain stable organic dyes with intense absorption around λ=1100 nm is re... more A diradical approach to obtain stable organic dyes with intense absorption around λ=1100 nm is reported. The para- and meta-quinodimethane-bridged BODIPY dimers BD-1 and BD-2 were synthesized and were found to have a small amount of diradical character. These molecules exhibited very intense absorption at λ=1088 nm (ɛ=6.65×10(5) M(-1) cm(-1) ) and 1136 nm (ɛ=6.44×10(5) M(-1) cm(-1) ), respectively, together with large two-photon-absorption cross-sections. Structural isomerization induced little variation in their diradical character but distinctive differences in their physical properties. Moreover, the compounds showed a selective fluorescence turn-on response in the presence of the hydroxyl radical but not with other reactive oxygen species.