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Arindam Saha

Bio: Arindam Saha is an academic researcher from Central Glass and Ceramic Research Institute. The author has contributed to research in topics: Nanoparticle & Drug delivery. The author has an hindex of 23, co-authored 39 publications receiving 2540 citations. Previous affiliations of Arindam Saha include Indian Institute of Technology Kharagpur & Lucideon.

Papers
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Journal ArticleDOI
TL;DR: Nitric acid oxidation induces nitrogen and oxygen incorporation into soot particles, which afforded water solubility and a light-emitting property; the isolation of small particles from a mixture of different sized particles improved the fluorescence quantum yield.
Abstract: Fluorescent carbon nanoparticles (CNPs) 2−6 nm in size with a quantum yield of about ∼3% were synthesized via nitric acid oxidation of carbon soot, and this approach can be used for milligram-scale synthesis of these water-soluble particles. These CNPs are nanocrystalline with a predominantly graphitic structure and show green fluorescence under UV exposure. Nitric acid oxidation induces nitrogen and oxygen incorporation into soot particles, which afforded water solubility and a light-emitting property; the isolation of small particles from a mixture of different sized particles improved the fluorescence quantum yield. These CNPs show encouraging cell-imaging applications. They enter into cells without any further functionalization, and the fluorescence property of these particles can be used for fluorescence-based cell imaging applications.

1,014 citations

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TL;DR: A chemical method is developed to synthesise highly fluorescent carbon nanoparticles 1–10 nm in size that exhibit size-dependent, tunable visible emission and have been transformed into various functionalised nanoprobes with hydrodynamic diameters and used as cell imaging probes.
Abstract: Fluorescent nanoparticle-based imaging probes have advanced current labelling technology and are expected to generate new medical diagnostic tools based on their superior brightness and photostability compared with conventional molecular probes. Although significant progress has been made in fluorescent semiconductor nanocrystal-based biological labelling and imaging, the presence of heavy metals and the toxicity issues associated with heavy metals have severely limited the application potential of these nanocrystals. Here, we report a fluorescent carbon nanoparticle-based, alternative, nontoxic imaging probe that is suitable for biological staining and diagnostics. We have developed a chemical method to synthesise highly fluorescent carbon nanoparticles 1–10 nm in size; these particles exhibit size-dependent, tunable visible emission. These carbon nanoparticles have been transformed into various functionalised nanoprobes with hydrodynamic diameters of 5–15 nm and have been used as cell imaging probes.

633 citations

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TL;DR: A "turn-off" surface enhanced Raman scattering (SERS)-based approach for reliable detection of cellular GSH and GSSG and is able to monitor GSH level during photothermal cancer therapy.
Abstract: Glutathione (GSH) and oxidized glutathione (GSSG) control cellular function and efficiency of anticancer therapy. Reliable detection of cellular GSH/GSSG is challenging due to their ultralow concentration (typically femtomolar concentrations) and interference by other thiol-based molecules. Here, we report a “turn-off” surface enhanced Raman scattering (SERS)-based approach for reliable detection of cellular GSH and GSSG. This approach exploits GSH-induced replacement of a Raman probe from the surface of γ-Fe2O3–Au followed by Ag growth around γ-Fe2O3–Au that generates electromagnetic hot spots at the junction between Au and Ag where the Raman probe is localized. The magnetic component of the hybrid nanoparticle concentrates the cellular GSH, and the Au/Ag-based plasmonic component provides electromagnetic hot spots for sensitive SERS. This approach is able to monitor GSH level during photothermal cancer therapy.

121 citations

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TL;DR: It is found that cross-linked coating, specifically by polyacrylate, provides a superior colloidal stability of nanoparticles and the robust coating provides the opportunity to explore various conjugation chemistries involving nanoparticle and to derive different soluble nanobioconjugates.
Abstract: Nanoparticle-based probes are emerging as alternatives to molecular probes with several advantages. A variety of water-soluble functional nanoparticles and nanobioconjugates need to be prepared and tested for this research. Development of appropriate coating chemistries is the key in deriving such functional nanoparticles. Herein we summarize different coating approaches those we have developed and compared them in the context of currently available coating methods, for the synthesis of soluble functional nanoparticles. We have focused on conventional ligand exchange, interdigited bilayer strategy, silica coating, polyacrylate coating, and imidazole based polymer coating and found that cross-linked coating, specifically by polyacrylate, provides a superior colloidal stability of nanoparticles. The robust coating provides the opportunity to explore various conjugation chemistries involving nanoparticle and to derive different soluble nanobioconjugates. A library of functional nanoprobes with hydrodynamic d...

87 citations

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TL;DR: It is shown that the folate receptor mediated cellular internalization mechanism of 35–50 nm nanoparticle shifts from caveolae- to clathrin-mediated endocytosis as the nanoparticle multivalency increases from 10 to 40 and results in the difference of their subcellular trafficking.
Abstract: Although nanoparticle multivalency is known to influence their biological labeling performance, the functional role of multivalency is largely unexplored. Here we show that the folate receptor mediated cellular internalization mechanism of 35–50 nm nanoparticle shifts from caveolae- to clathrin-mediated endocytosis as the nanoparticle multivalency increases from 10 to 40 and results in the difference of their subcellular trafficking. We have synthesized folate functionalized multivalent quantum dot (QD) with varied average numbers of folate per QD between 10 and 110 [e.g., QD(folate)10, QD(folate)20, QD(folate)40, QD(folate)110] and investigated their uptake and localization into folate receptor overexpressed HeLa and KB cells. We found that uptake of QD(folate)10 occurs predominantly via caveolae-mediated endocytosis and entirely trafficked to the perinuclear region. In contrast, uptake of QD(folate)20 occurs via both caveolae- and chathrin-mediated endocytosis; uptake of QD(folate)40 and QD(folate)110 o...

79 citations


Cited by
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Journal ArticleDOI
TL;DR: This Review summarize recent advances in the synthesis and characterization of C-dots and speculate on their future and discuss potential developments for their use in energy conversion/storage, bioimaging, drug delivery, sensors, diagnostics, and composites.
Abstract: Similar to its popular older cousins the fullerene, the carbon nanotube, and graphene, the latest form of nanocarbon, the carbon nanodot, is inspiring intensive research efforts in its own right. These surface-passivated carbonaceous quantum dots, so-called C-dots, combine several favorable attributes of traditional semiconductor-based quantum dots (namely, size- and wavelength-dependent luminescence emission, resistance to photobleaching, ease of bioconjugation) without incurring the burden of intrinsic toxicity or elemental scarcity and without the need for stringent, intricate, tedious, costly, or inefficient preparation steps. C-dots can be produced inexpensively and on a large scale (frequently using a one-step pathway and potentially from biomass waste-derived sources) by many approaches, ranging from simple candle burning to in situ dehydration reactions to laser ablation methods. In this Review, we summarize recent advances in the synthesis and characterization of C-dots. We also speculate on their future and discuss potential developments for their use in energy conversion/storage, bioimaging, drug delivery, sensors, diagnostics, and composites.

3,991 citations

Journal ArticleDOI
TL;DR: The progress in the research and development of CQDs is reviewed with an emphasis on their synthesis, functionalization and technical applications along with some discussion on challenges and perspectives in this exciting and promising field.
Abstract: Fluorescent carbon nanoparticles or carbon quantum dots (CQDs) are a new class of carbon nanomaterials that have emerged recently and have garnered much interest as potential competitors to conventional semiconductor quantum dots. In addition to their comparable optical properties, CQDs have the desired advantages of low toxicity, environmental friendliness low cost and simple synthetic routes. Moreover, surface passivation and functionalization of CQDs allow for the control of their physicochemical properties. Since their discovery, CQDs have found many applications in the fields of chemical sensing, biosensing, bioimaging, nanomedicine, photocatalysis and electrocatalysis. This article reviews the progress in the research and development of CQDs with an emphasis on their synthesis, functionalization and technical applications along with some discussion on challenges and perspectives in this exciting and promising field.

3,514 citations

Journal ArticleDOI
TL;DR: In this article, a review of the photo and electron properties of carbon nanodots is presented to provide further insight into their controversial emission origin and to stimulate further research into their potential applications, especially in photocatalysis, energy conversion, optoelectronics, and sensing.
Abstract: Carbon nanodots (C-dots) have generated enormous excitement because of their superiority in water solubility, chemical inertness, low toxicity, ease of functionalization and resistance to photobleaching. In this review, by introducing the synthesis and photo- and electron-properties of C-dots, we hope to provide further insight into their controversial emission origin (particularly the upconverted photoluminescence) and to stimulate further research into their potential applications, especially in photocatalysis, energy conversion, optoelectronics, and sensing.

2,262 citations

Journal ArticleDOI
Shoujun Zhu1, Yubin Song1, Xiaohuan Zhao1, Jieren Shao1, Junhu Zhang1, Bai Yang1 
TL;DR: The actual mechanism of photoluminescence (PL) of fluorescent carbon dots (CDs) is still an open debate among researchers as mentioned in this paper, and three types of fluorescent CDs were involved: graphene quantum dots (GQDs), carbon nanodots (CNDs), and polymer dots (PDs).
Abstract: At present, the actual mechanism of the photoluminescence (PL) of fluorescent carbon dots (CDs) is still an open debate among researchers. Because of the variety of CDs, it is highly important to summarize the PL mechanism for these kinds of carbon materials; doing so can guide the development of effective synthesis routes and novel applications. This review will focus on the PL mechanism of CDs. Three types of fluorescent CDs were involved: graphene quantum dots (GQDs), carbon nanodots (CNDs), and polymer dots (PDs). Four reasonable PL mechanisms have been confirmed: the quantum confinement effect or conjugated π-domains, which are determined by the carbon core; the surface state, which is determined by hybridization of the carbon backbone and the connected chemical groups; the molecule state, which is determined solely by the fluorescent molecules connected on the surface or interior of the CDs; and the crosslink-enhanced emission (CEE) effect. To give a thorough summary, the category and synthesis routes, as well as the chemical/physical properties for the CDs, are briefly introduced in advance.

1,987 citations

Journal ArticleDOI
TL;DR: It is reported that during the acid treatment and chemical exfoliation of traditional pitch-based carbon fibers, that are both cheap and commercially available, the stacked graphitic submicrometer domains of the fibers are easily broken down, leading to the creation of GQDs with different size distribution in scalable amounts.
Abstract: Graphene quantum dots (GQDs), which are edge-bound nanometer-size graphene pieces, have fascinating optical and electronic properties. These have been synthesized either by nanolithography or from starting materials such as graphene oxide (GO) by the chemical breakdown of their extended planar structure, both of which are multistep tedious processes. Here, we report that during the acid treatment and chemical exfoliation of traditional pitch-based carbon fibers, that are both cheap and commercially available, the stacked graphitic submicrometer domains of the fibers are easily broken down, leading to the creation of GQDs with different size distribution in scalable amounts. The as-produced GQDs, in the size range of 1–4 nm, show two-dimensional morphology, most of which present zigzag edge structure, and are 1–3 atomic layers thick. The photoluminescence of the GQDs can be tailored through varying the size of the GQDs by changing process parameters. Due to the luminescence stability, nanosecond lifetime, ...

1,980 citations