Publications by authors named "Pratima R Solanki"

59 Publications

Gut microbiota-derived metabolites in CRC progression and causation.

J Cancer Res Clin Oncol 2021 Jul 17. Epub 2021 Jul 17.

Gene Regulation Laboratory, National Institute of Immunology, New Delhi, 110067, India.

Background: Based on recent research reports, dysbiosis and improper concentrations of microbial metabolites in the gut may result into the carcinogenesis of colorectal cancer. Recent advancement also highlights the involvement of bacteria and their secreted metabolites in the cancer causation. Gut microbial metabolites are functional output of the host-microbiota interactions and produced by anaerobic fermentation of food components in the diet. They contribute to influence variety of biological mechanisms including inflammation, cell signaling, cell-cycle disruption which are majorly disrupted in carcinogenic activities.

Purpose: In this review, we intend to discuss recent updates and possible molecular mechanisms to provide the role of bacterial metabolites, gut bacteria and diet in the colorectal carcinogenesis. Recent evidences have proposed the role of bacteria, such as Fusobacterium nucleaturm, Streptococcus bovis, Helicobacter pylori, Bacteroides fragilis and Clostridium septicum, in the carcinogenesis of CRC. Metagenomic study confirmed that these bacteria are in increased abundance in CRC patient as compared to healthy individuals and can cause inflammation and DNA damage which can lead to development of cancer. These bacteria produce metabolites, such as secondary bile salts from primary bile salts, hydrogen sulfide, trimethylamine-N-oxide (TMAO), which are likely to promote inflammation and subsequently cancer development.

Conclusion: Recent studies suggest that gut microbiota-derived metabolites have a role in CRC progression and causation and hence, could be implicated in CRC diagnosis, prognosis and therapy.
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http://dx.doi.org/10.1007/s00432-021-03729-wDOI Listing
July 2021

Non-enzymatic and rapid detection of glucose on PVA-CuO thin film using ARDUINO UNO based capacitance measurement unit.

Biomed Microdevices 2021 07 14;23(3):36. Epub 2021 Jul 14.

Special Centre for Nanoscience, Jawaharlal Nehru University, New Delhi-110067, India.

Glucose measurement is one of the essential health monitoring practices for maintaining blood sugar levels. Here, we have fabricated a highly specific capacitive nano-sensor for non-enzymatic glucose detection. Capacitance measurements were carried out on polyvinyl alcohol capped copper oxide (PVA-CuO) thin films on indium tin oxide (ITO) coated glass using ARDUINO UNO. The capacitance study shows a decrease in capacitance with an increase in glucose concentrations. The applicability in real samples was performed by studying the glucose in the presence of fetal bovine serum. Most commonly found interfering agents were used for interference studies, which confirmed the capacitive nano-sensor specificity. The system was further checked for repeatability up to six readings and reproducibility up to 5 chips. The shelf-life study showed stability for four weeks of a chip. These studies indicate that this capacitance-based measurement unit can be used for reliable, rapid, and non-enzymatic detection of glucose in real sample.
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http://dx.doi.org/10.1007/s10544-021-00568-xDOI Listing
July 2021

Fabrication of label-free and ultrasensitive electrochemical immunosensor based on molybdenum disulfide nanoparticles modified disposable ITO: An analytical platform for antibiotic detection in food samples.

Food Chem 2021 Nov 29;363:130245. Epub 2021 May 29.

Special Centre for Nanoscience, Jawaharlal Nehru University, New Delhi 110067, India. Electronic address:

Here, we aimed to fabricate a label-free immunosensing platform for the first time based on molybdenum disulfide nanoparticles (nMoSNPs) deposited on ITO) coated glass substrate for the electrochemical detection of ampicillin (AMP). The stable and high surface area of nMoSNPs were made by a low-temperature one-step hydrothermal route, bestowing the carrying capacity of anti-AMP (antibody against AMP) through an amide linkage. The spectroscopic, morphological, and structural characterization of the proposed electrodes were performed using various analytical and electrochemical techniques. The differential pulse voltammetry technique was utilized to evaluate anti-AMP and AMP interaction on the electrode surface. The developed immunosensor exhibits high sensitivity, a broad detection range having a significant detection limit towards detection of AMP having excellent selectivity, acceptable stability, and reproducibility. Furthermore, the applicability of the proposed immunosensor was tested in spiked milk, water, and orange juice, and the results confirmed the consistency of the immunosensor.
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http://dx.doi.org/10.1016/j.foodchem.2021.130245DOI Listing
November 2021

Evaluation of size, shape, and charge effect on the biological interaction and cellular uptake of cerium oxide nanostructures.

Nanotechnology 2021 Jun 11;32(35). Epub 2021 Jun 11.

Special Centre for Nanoscience, Jawaharlal Nehru University, New Delhi-110067, India.

Cerium oxide (CeO) at the nanoscale has prolifically attracted the immense interest of researchers due to its switchable oxidation states (Ce/Ce) that play a crucial role in many biological activities. The present work reports the evaluation of size, shape, and charge effect on the biological interaction with RAW 264.7 cells for three nanostructures of CeO(CeONS) namely nanocubes (NCs), nanorods (NRs), and nanoparticles (NPs). These NS exhibits similar composition and have average diameter values in the order of NCs < NRs ≅ NPs. The values of zeta potential revealed the anionic nature of NS with surface charge in order of NCs < NPs < NRs. The cellular interaction of CeONS was analyzed for cytotoxicity, cellular uptake, and morphological studies. Quantitative determination of the uptake of CeONS exhibited concentration-dependent uptake in the order as NCs > NPs > NRs. The proposed possible mechanisms of cellular uptake revealed that different structures tended to use the various endocytosis pathways in different proportions.
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http://dx.doi.org/10.1088/1361-6528/ac03d5DOI Listing
June 2021

Carbon cloth-based immunosensor for detection of 25-hydroxy vitamin D.

Mikrochim Acta 2021 04 1;188(4):145. Epub 2021 Apr 1.

Special Centre for Nanoscience, Jawaharlal Nehru University, New Delhi, 110067, India.

Vitamin D (VD) deficiency is a global health concern due to its serious health impacts, and at present, the monitoring of VD status is expensive. Here, a novel immunosensor for sensitive and label-free detection of 25-hydroxy vitamin D (25VD) is reported. Nanostructured cerium(IV) oxide (nCeO) was anchored onto carbon cloth (CC) via electrophoretic deposition to fabricate a nanoplatform (nCeO/CC). Subsequently, bioactive molecules (anti-25VD and BSA) were introduced to fabricate the nanobioplatform BSA/anti-25VD/nCeO/CC as an immunosensor. The analytical performance of the developed immunosensor was studied towards 25VD detection. The immunosensor provides a broad linear range of 1-200 ng mL, high sensitivity of 2.08 μA ng mL cm, a detection limit of 4.63 ng mL, and a response time of 15 min, which is better than that of previous reports. The biosensor exhibited high selectivity, good reproducibility, and excellent stability for about 45 days. The potential application of the proposed immunosensor was observed for real serum samples towards 25VD detection that demonstrated a high correlation with the conventional enzyme-linked immunosorbent assay. Graphical abstract.
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http://dx.doi.org/10.1007/s00604-021-04751-yDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8012417PMC
April 2021

Mechanism of action and cellular responses of HEK293 cells on challenge with zwitterionic carbon dots.

Colloids Surf B Biointerfaces 2021 Jun 19;202:111698. Epub 2021 Mar 19.

Toxicology Division, Biomedical Technology Wing, Sree Chitra Tirunal Institute for Medical Sciences and Technology (Govt. of India), Poojapura, Trivandrum 695 012, Kerala, India. Electronic address:

Carbon, an extremely versatile element has great demand in the field of nanoscience. Carbon-based nanostructures are exponentially increased due to its wide range of applications in biotechnological and environmental approaches; hence, its safety assessment is of greater concern. In the present study, high quantum yielding zwitterionic carbon dots were synthesized, characterized and its safety assessment at different concentration ranges (50-1600 μgmL) on HEK 293 cells was carried out. Cellular, mitochondrial, lysosomal integrity and ROS generation were assessed using specific fluorochromes.The key cellular event apoptosis was assessed by annexinpropidium iodide staining using imaging flow cytometry. Moreover, the mRNA levels of the apoptotic genes were determined by real-time PCR. The results revealed that the cell viability assays (MTT, NR) and mitochondrial membrane potential were altered on exposure to a higher concentration of zwitterionic CDs for 24 h. Also, annexinpropidiumiodidestaining exhibited an increased percentage of apoptotic cells upon exposure to zwitterionic CDs at higher concentrations. Further, apoptosis was confirmed by significantlyincreased expression of pro-apoptotic gene (Bax) together with decreased expression of Bcl-2/Bax ratio. Collectively, this study suggests that zwitterionic CDs induce apoptosis in HEK 293 at higher concentration and the safe range for its intended application is found to be 50-200 μg/mL.
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http://dx.doi.org/10.1016/j.colsurfb.2021.111698DOI Listing
June 2021

Gut microbiota derived trimethylamine N-oxide (TMAO) detection through molecularly imprinted polymer based sensor.

Sci Rep 2021 01 14;11(1):1338. Epub 2021 Jan 14.

National Institute of Immunology, New Delhi, India.

Trimethylamine N-oxide (TMAO), a microbiota-derived metabolite has been implicated in human health and disease. Its early detection in body fluids has been presumed to be significant in understanding the pathogenesis and treatment of many diseases. Hence, the development of reliable and rapid technologies for TMAO detection may augment our understanding of pathogenesis and diagnosis of diseases that TMAO has implicated. The present work is the first report on the development of a molecularly imprinted polymer (MIP) based electrochemical sensor for sensitive and selective detection of TMAO in body fluids. The MIP developed was based on the polypyrrole (PPy), which was synthesized via chemical oxidation polymerization method, with and without the presence of TMAO. The MIP, NIP and the non-sonicated polymer (PPy-TMAO) were separately deposited electrophoretically onto the hydrolyzed indium tin oxide (ITO) coated glasses. The chemical, morphological, and electrochemical behavior of MIP, non-imprinted polymer (NIP), and PPy-TMAO were characterized using Fourier transform infrared spectroscopy (FT-IR), scanning electron microscopy (SEM), and electrochemical techniques. The detection response was recorded using differential pulse voltammetry (DPV), which revealed a decrease in the peak current with the increase in concentration of TMAO. The MIP sensor showed a dynamic detection range of 1-15 ppm with a sensitivity of 2.47 µA mL ppm cm. The developed sensor is easy to construct and operate and is also highly selective to detect TMAO in body fluids such as urine. The present research provides a basis for innovative strategies to develop sensors based on MIP to detect other metabolites derived from gut microbiota that are implicated in human health and diseases.
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http://dx.doi.org/10.1038/s41598-020-80122-6DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7809026PMC
January 2021

Omics technologies for improved diagnosis and treatment of colorectal cancer: Technical advancement and major perspectives.

Biomed Pharmacother 2020 Nov 19;131:110648. Epub 2020 Oct 19.

Gene Regulation Laboratory, National Institute of Immunology, New Delhi 110067, India. Electronic address:

Colorectal cancer (CRC) ranks third among the most commonly occurring cancers worldwide, and it causes half a million deaths annually. Alongside mechanistic study for CRC detection and treatment by conventional techniques, new technologies have been developed to study CRC. These technologies include genomics, transcriptomics, proteomics, and metabolomics which elucidate DNA markers, RNA transcripts, protein and, metabolites produced inside the colon and rectum part of the gut. All these approaches form the omics arena, which presents a remarkable opportunity for the discovery of novel prognostic, diagnostic and therapeutic biomarkers and also delineate the underlying mechanism of CRC causation, which may further help in devising treatment strategies. This review also mentions the latest developments in metagenomics and culturomics as emerging evidence suggests that metagenomics of gut microbiota has profound implications in the causation, prognosis, and treatment of CRC. A majority of bacteria cannot be studied as they remain unculturable, so culturomics has also been strengthened to develop culture conditions suitable for the growth of unculturable bacteria and identify unknown bacteria. The overall purpose of this review is to succinctly evaluate the application of omics technologies in colorectal cancer research for improving the diagnosis and treatment strategies.
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http://dx.doi.org/10.1016/j.biopha.2020.110648DOI Listing
November 2020

Dimanganese trioxide (MnO) based label-free electrochemical biosensor for detection of Aflatoxin-B1.

Bioelectrochemistry 2021 Feb 13;137:107684. Epub 2020 Oct 13.

Special Centre for Nanoscience, Jawaharlal Nehru University (JNU), New Delhi 110067, India. Electronic address:

This work presents, a manganese oxide nanoparticles (MnOnps) based electrochemical immunosensor for the detection of Aflatoxin-B1 (AFB1). X-ray diffrraction spectroscopy study confirms the purely synthesized MnOnps with an average crystallite size of 31.5 nm. Transmission electron microscopy study confirms average particle size of 45 nm. To fabricate an electrochemical biosensor, a thin film of MnOnps was fabricated onto indium tin oxide (ITO) surface using electrophoretic technique. Such fabricated thin film was utilized to immobilize antibodies (Anti-AFB1) for the selective detection of AFB1 using differential pulse voltammetry technique. Prior to perform sensing, bovine serum albumin (BSA) was utilized to block the uncovered sites on the Anti-AFB1/MnO/ITO immunoelectrode surface. The response of BSA/Anti-AFB1/MnO/ITO immunoelectrode was measured as a function of AFB1 in a linear detection range of 1 pg mL to 10 µg mL and sensor showed highest sensitivity of 2.044 μA mL ngcm with lower detection limit of 0.54 pg mL. A spiked sample response of corn extract was studied in the linear range of 1 pg mL to 10 µg mL and immunoelectrode (BSA/Anti-AFB1/MnO/ITO) showed recovery rate of 98.6 %.
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http://dx.doi.org/10.1016/j.bioelechem.2020.107684DOI Listing
February 2021

Fluorescence tuning behavior of carbon quantum dots with gold nanoparticles via novel intercalation effect of aldicarb.

Food Chem 2021 Mar 19;340:127835. Epub 2020 Aug 19.

Special Centre for Nanoscience, Jawaharlal Nehru University, New Delhi 110067, India. Electronic address:

A simple, sensitive and rapid fluorometric system has been developed for the detection of aldicarb (ALD) based on inner filter effect (IFE) of gold nanoparticles (AuNPs) on fluorescence (FL) intensity of carbon quantum dots (CQDs). Addition of CQDs into AuNPs, gets them aggregated due to electrostatic interaction resulting in quenching the FL intensity of CQDs. With addition of ALD into AuNPs, an intercalated layer was formed between them through Au-N and Au-S bond which reduced IFE of AuNPs. Hence, CQDs FL intensity recovered along with ALD concentration varying between 3.8 and 76 µg L with lower detection limit of 3.02 µg L. The spiked real samples study in fruits, vegetables and soft drinks revealed that this sensing platform was repeatable and effective for real samples. The validation of proposed method indicates that the ALD sensor is promising and adaptable for everyday on spot environment and food safety monitoring.
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http://dx.doi.org/10.1016/j.foodchem.2020.127835DOI Listing
March 2021

Strategies and perspectives to develop SARS-CoV-2 detection methods and diagnostics.

Biomed Pharmacother 2020 Sep 19;129:110446. Epub 2020 Jun 19.

Special Centre for Nanoscience, Jawaharlal Nehru University, New Delhi, 110067, India. Electronic address:

To develop diagnostics and detection methods, current research is focussed on targeting the detection of coronavirus based on its RNA. Besides the RNA target, research reports are coming to develop diagnostics by targeting structure and other parts of coronavirus. PCR based detection system is widely used and various improvements in the PCR based detection system can be seen in the recent research reports. This review will discuss multiple detection methods for coronavirus for developing appropriate, reliable, and fast alternative techniques. Considering the current scenario of COVID-19 diagnostics around the world and an urgent need for the development of reliable and cheap diagnostic, various techniques based on CRISPR technology, antibody, MIP, LAMP, microarray, etc. should be discussed and tried.
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http://dx.doi.org/10.1016/j.biopha.2020.110446DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7303646PMC
September 2020

Silver molybdate nanoparticles based immunosensor for the non-invasive detection of Interleukin-8 biomarker.

Mater Sci Eng C Mater Biol Appl 2020 Aug 2;113:110911. Epub 2020 Apr 2.

Special Centre for Nanoscience, Jawaharlal Nehru University, New Delhi 110067, India. Electronic address:

In this study, we report the silver molybdate nanoparticles (β-AgMoO NPs) based non-invasive and sensitive electrochemical immunosensor for label-free detection of Interleukin-8 (IL-8) biomarker. The X-ray diffraction and Raman spectroscopy studies confirm the cubic spinel structures of β-AgMoO NPs. High-resolution transmission electron microscopy study depicted average size of β-AgMoO NPs as 27.15 nm. The cleaned indium tin oxide coated glass substrates were coated with spin-coated thin films of AgMoO NPs. These electrodes used for covalently immobilization of antibodies specific to IL-8 (Anti-IL-8) using EDC-NHS chemistry and unbound activated sites blocked by bovine serum albumin. Electrochemical response was obtained in the range of 1 fg mL to 40 ng mL and the sensitivity was found to be 7.03 μA ngmL cm with LOD of 90 pg mL. Spiked samples prepared by human saliva were tested and found efficient detection with this immunoelectrode.
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http://dx.doi.org/10.1016/j.msec.2020.110911DOI Listing
August 2020

Studies on carbon-quantum-dot-embedded iron oxide nanoparticles and their electrochemical response.

Nanotechnology 2020 Aug 12;31(35):355502. Epub 2020 May 12.

Special Centre for Nanoscience, Jawaharlal Nehru University, New Delhi, India.

A report on the synthesis of carbon-quantum-dot-embedded iron oxide nanoparticles ([email protected]) and their improved electrochemical studies is presented. FeONPs and [email protected] were synthesized by the wet-chemical co-precipitation method. X-ray diffraction measurements exhibited pure cubic phase with Fd3m space group in FeONPs and [email protected] Fourier-transform infrared spectroscopy measurements confirmed the functionalization of FeONPs with CQDs. Dynamic light scattering measurements revealed a hydrodynamic radius of 520 nm and 319 nm for FeONPs and [email protected], respectively. Moreover, zeta potential measurements showed positively charged FeONPs and negatively charged [email protected] High-resolution transmission electron microscopy measurements showed nearly spherical structure with an average size of around 7 nm for FeO in both samples, whereas CQDs were nearly 2 nm in size in [email protected] A biocompatibility study showed that [email protected] were more biocompatible than the bare FeONPs. [email protected] were then dispersed in chitosan (CHIT) solution, and drop-casted onto an indium tin oxide (ITO) glass substrate for further study. Atomic force microscopy results showed improved surface roughness of the [email protected]/ITO electrode, providing a better biosensing platform. The electrochemical response studies of [email protected]/ITO also showed enhanced electrochemical signal compared to FeO-CHIT/ITO electrodes. Thus, a [email protected]/ITO electrode was used for the detection of vitamin D (10-100 ng ml) using a differential pulse voltammetry technique. The sensitivity and limit of detection were obtained as 0.069 µA ng ml cm and 2.46 ng ml, respectively.
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http://dx.doi.org/10.1088/1361-6528/ab925eDOI Listing
August 2020

One-Step Synthesized ZnO np-Based Optical Sensors for Detection of Aldicarb via a Photoinduced Electron Transfer Route.

ACS Omega 2020 Feb 7;5(6):2552-2560. Epub 2020 Feb 7.

Special Centre for Nanoscience and School of Physical Sciences, Jawaharlal Nehru University, New Delhi 110067, India.

Pesticides are used in agriculture for crop production enhancement by controlling pests, but they have acute toxicological effects on other life forms. Thus, it becomes imperative to detect their concentration in food products in a fast and accurate manner. In this study, ZnO nanoparticles (ZnO nps) have been used as optical sensors for the detection of pesticide Aldicarb via a photoinduced electron transfer (PET) route. ZnO nps were synthesized directly by calcining zinc acetate at 450, 500, and 550 °C for 2 h. ZnO nps were characterized by X-ray diffraction (XRD), Raman spectroscopy, scanning electron microscopy (SEM), and UV-vis absorption and photoluminescence (PL) spectroscopies to study the phase, crystallinity, shape, morphology, absorbance, and fluorescence of the prepared ZnO nps. XRD and Raman studies confirmed the crystalline nature of ZnO nps. The average crystallite size obtained was 13-20 nm from the XRD study. The SEM study confirmed spherical-shaped ZnO nps with average sizes in the range of 70-150 nm. The maximum absorbance was obtained in the 200-500 nm regions with a prominent peak absorbance at 372 nm from UV-vis spectra. The corresponding band gap for ZnO nps was calculated using Tauc's plots and was found to be 3.8, 3.67, and 3.45 eV for the 450, 500, and 550 °C calcined samples, respectively. The fluorescence spectra showed an increase in the intensity along with the increase in the size of ZnO nps. The ZnO nps (samples calcined at 500 and 550 °C) exhibited a response toward Aldicarb, owing to their pure phase and higher PL intensity. Both the samples showed systematic detection of Aldicarb in the range of 250 pM to 2 nM (500 °C) and 250 pM to 5 nM (550 °C). Among the various quenching mechanisms, PET was found to be the dominant process for the detection of Aldicarb. This method can be used for the detection of Aldicarb in real (food) samples using a portable fluorimeter.
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http://dx.doi.org/10.1021/acsomega.9b01987DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7033663PMC
February 2020

A highly sensitive label-free amperometric biosensor for norfloxacin detection based on chitosan-yttria nanocomposite.

Int J Biol Macromol 2020 May 11;151:566-575. Epub 2020 Feb 11.

Special Centre for Nanoscience, Jawaharlal Nehru University, New Delhi 110067, India. Electronic address:

Here, non-invasive and label-free detection of trace-level of norfloxacin (NF) in human urine samples has been reported using the electrochemical technique. Nanostructured yttrium oxide (nYO) was synthesized at low-temperature using a one-step hydrothermal process. These nYO were characterized by various methods including XRD, FT-IR, Raman spectroscopy, and TEM. A biosensing platform based on nYO modified with chitosan (CH) was fabricated for the detection of NF. The nanocomposite film (CH-YO/ITO) was characterized by FE-SEM, contact angle measurements, and electrochemical techniques. Further, fluoroquinolones antibodies (anti-FQ) were used to modify the CH-YO/ITO electrode via covalent interaction. Non-specific sites were blocked by bovine serum albumin (BSA), those present on the anti-FQ/CH-YO/ITO electrode surface. The response study of BSA/anti-FQ/CH-YO/ITO bioelectrode towards NF detection revealed a wide range (1 pM-10 μM) with a lower detection limit of 3.87 pM using differential pulse voltammetry (DPV). The sensitivity obtained is as high as 10.14 μA μM cm with a fast response time of ~10 min. Moreover, the diagnostic performance of the fabricated sensor was evaluated to detect NF in urine spiked sample. The recovery of NF from the spiked sample was observed from 90.5 to 101.1%, with a maximum relative standard deviation of 7.04. The obtained results of the fabricated bioelectrode (BSA/anti-FQ/CH-YO/ITO) was validated with ELISA. The results were found better when compared with earlier described biosensors and commercially existing ELISA in terms of sensitivity and lower detection limit.
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http://dx.doi.org/10.1016/j.ijbiomac.2020.02.089DOI Listing
May 2020

Highly Biocompatible, Fluorescence, and Zwitterionic Carbon Dots as a Novel Approach for Bioimaging Applications in Cancerous Cells.

ACS Appl Mater Interfaces 2018 Nov 23;10(44):37835-37845. Epub 2018 Oct 23.

Special Centre for Nanoscience , Jawaharlal Nehru University , New Delhi 110067 , India.

Highly biocompatible, excellently photostable, nitrogen- and sulfur-containing novel zwitterionic carbon dots (CDs) were synthesized by microwave-assisted pyrolysis. The size of CDs were 2-5 nm, with an average size of 2.61 ± 0.7 nm. CDs were characterized by UV/vis spectroscopy, fluorescence spectroscopy, zeta potential, Fourier-transform infrared spectroscopy, X-ray diffraction, and time-resolved fluorescence spectroscopy. CDs were known to emit blue fluorescence when excited at 360 nm, that is, UV region, and emit in the blue region of visible spectrum, that is, at 443 nm. CDs showed excitation-independent photoluminescence behavior and were highly fluorescent even at lower concentration under UV light. These CDs were highly fluorescent in nature, with the quantum yield being as high as 80%, which is comparable to that of organic dyes. The CDs were further used to image two different oral cancer cell lines, namely, FaDu (human pharyngeal carcinoma) and Cal-27 (human tongue carcinoma). The cell viability assay demonstarted that CDs were highly biocompatible, which was further confirmed by the side scattering studies as no change in the granularity was observed even at the highest concentration of 1600 μg/mL. The generation of reactive oxygen species (ROS) was also investigated and negligible generaton of ROS was detected. In addition to that, the uptake phenomenon, cell cycle analysis, exocytosis, and cellular uptake at 4 °C and in the presence of ATP inhibitor were studied. It was found that CDs easily cross the plasma membrane without hampering the cellular integrity.
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http://dx.doi.org/10.1021/acsami.8b13217DOI Listing
November 2018

Electrochemical immunosensor based on magnetite nanoparticles incorporated electrospun polyacrylonitrile nanofibers for Vitamin-D detection.

Mater Sci Eng C Mater Biol Appl 2018 Dec 20;93:145-156. Epub 2018 Jul 20.

Special centre for Nanoscience, Jawaharlal Nehru University, New Delhi 110067, India. Electronic address:

In the present study, magnetite nanoparticles (FeO NPs) incorporated polyacrylonitrile nanofibers (PANnFs) having diameter of 350-500 nm, were electrospun and directly collected onto indium tin oxide (ITO) coated glass substrate. X-ray diffraction pattern of FeO‑PANnFs confirmed the existence of FeO NPs within the PANnFs. Nafion was used to make FeO‑PANnFs more adhesive to the ITO surface. Partial hydrolyzation of FeO‑PANnFs/ITO electrode was done using NaOH solution for the partial conversion of nitrile group (C≡N) into carboxyl and amine groups that was confirmed by Fourier transform infrared spectroscopy study. The hydrolyzed FeO‑PANnFs/ITO electrode was used as an immobilization matrix for monoclonal antibody specific to Vitamin-D (Anti‑VD) via 1‑ethyl‑3‑(3‑dimethylaminopropyl) carbodiimide and N‑Hydroxysuccinimide chemistry. Bovine serum albumin (BSA) was used as a blocking agent to block the non-specific sites onto Anti‑VD/FeO‑PANnFs/ITO electrode surface. Fabricated BSA/Anti‑VD/FeO‑PANnFs/ITO immunoelectrode showed improved biosensing parameters for Vitamin-D detection such as sensitivity of 0.90 μA ng mL cm, limit of detection of 0.12 ng mLand detection range of 10-100 ng mL. The association and dissociation constants were obtained as 74.62 ng mL, 4.6 ng mL, respectively.
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http://dx.doi.org/10.1016/j.msec.2018.07.036DOI Listing
December 2018

Cubic CeO implanted reduced graphene oxide-based highly sensitive biosensor for non-invasive oral cancer biomarker detection.

J Mater Chem B 2018 May 25;6(19):3000-3012. Epub 2018 Apr 25.

Special Centre for Nanoscience, Jawaharlal Nehru University, New Delhi-110067, India.

Herein, we report a cerium oxide nanocubes (ncCeO)-reduced graphene oxide (RGO)-based nanocomposite for the detection of oral cancer biomarker, cytokeratin fragment-21-1 (Cyfra-21-1), using the electrochemical technique. Nanocomposite of ncCeO-RGO was prepared by the in situ reduction of graphene oxide (GO), in the presence of ncCeO, using hydrazine hydrate. Raman spectra confirmed the presence of ncCeO in the matrix of RGO. The chemical composition of the ncCeO-RGO nanocomposite was determined by X-ray photoelectron spectroscopy (XPS). X-ray diffraction (XRD) studies have indicated the presence of crystalline ncCeO and the amorphous nature of RGO. Thin films of ncCeO-RGO composites were spin coated onto the indium tin oxide (ITO) coated glass surface and used for the co-immobilization of specific antibody of Cyfra-21-1 by N-ethyl-N-(3-dimethyl aminopropyl)carbodiimide hydrochloride and N-hydroxysuccinimide (EDC-NHS) coupling chemistry. Electrochemical response studies were monitored by using the differential pulse voltammetry (DPV) technique in the range of 0.625 pg mL to 15 ng mL. The best linear response was observed in the range of 0.625 pg mL to 0.01 ng mL, with a low detection limit of 0.625 pg mL. The sensitivity was found to be 14.5 μA ng mL cm with R 0.98, which was an improvement compared to the results from previously reported work. This BSA/anti-Cyfra-21-1/ncCeO-RGO/ITO immunosensor shows selectivity towards Cyfra-21-1 in the presence of glucose, sodium chloride (NaCl), mucin 16 (MUC-16) and interleukin 8 (IL-8).
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http://dx.doi.org/10.1039/c8tb00653aDOI Listing
May 2018

Carbon dots-modified chitosan based electrochemical biosensing platform for detection of vitamin D.

Int J Biol Macromol 2018 Apr 21;109:687-697. Epub 2017 Dec 21.

Special Centre for Nanoscience, Jawaharlal Nehru University, New Delhi, India. Electronic address:

Here in, a carbon dots (CDs)-modified chitosan (CH) based biosensing platform was fabricated for vitamin D detection. Carbon dots were synthesized through microwave pyrolysis method, and characterized with transmission electron microscopy, Raman spectroscopy, Fourier transform infrared spectroscopy, and UV/VIS spectroscopy. Chitosan (1%) solution was prepared in acetic acid (1%) solution and followed by the addition of CDs to prepare the carbon dots-chitosan (CD-CH) composite. A thin film of CD-CH composite was prepared onto ITO glass substrate (CD-CH/ITO) by drop casting method. Surface of the composite film was characterized by atomic force microscopy, static contact angle measurement and cyclic voltammetry. CD-CH/ITO surface was further modified with immobilization of vitamin D antibody (Ab-VD) and bovine serum albumin (BSA) to prepare BSA/Ab-VD/CD-CH/ITO bioelectrode. Electrochemical response of the bioelectrode towards vitamin D antigen (Ag-VD) was carried out by differential pulse voltammetry. The biosensing electrode showed linearity within the range 10-50 ng mL of Ag-VD concentration. The sensitivity was found to be 0.2 μA ng mL cm, LOD was 1.35 ng mL, and the biosensor had a shelf-life of about 25 days.
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http://dx.doi.org/10.1016/j.ijbiomac.2017.12.122DOI Listing
April 2018

Lead and Chromium Adsorption from Water using L-Cysteine Functionalized Magnetite (FeO) Nanoparticles.

Sci Rep 2017 08 9;7(1):7672. Epub 2017 Aug 9.

Special Centre for Nanoscience, Jawaharlal Nehru University, New Delhi, 110067, India.

L-Cysteine functionalized magnetite nanoparticles (L-Cyst-FeO NPs) were synthesized by chemical co-precipitation using Fe and Fe as iron precursors, sodium hydroxide as a base and L-Cysteine as functionalized agent. The structural and morphological studies were carried out using X-ray powder diffraction, transmission electron microscopy, dynamic light scattering, scanning electron microscopy and energy dispersive X-ray spectroscopy, Fourier transform infrared spectroscopy, and UV-Vis spectrophotometric techniques. The zeta potential of bare FeO and functionalized L-Cyst-FeO NPs were +28 mV and -30.2 mV (pH 7.0), respectively. The positive surface charge changes to negative imply the presence of L-Cyst monolayer at particle interface. Band gap energy of 2.12 eV [bare FeONPs] and 1.4 eV [L-Cyst-FeO NPs] were obtained. Lead and chromium removal were investigated at different initial pHs, contact time, temperatures and adsorbate-adsorbent concentrations. Maximum Cr and Pb removal occurred at pH 2.0 and 6.0, respectively. Sorption dynamics data were best described by pseudo-second order rate equation. Pb and Cr sorption equilibrium data were best fitted to Langmuir equation. Langmuir adsorption capacities of 18.8 mg/g (Pb) and 34.5 mg/g (Cr) at 45 °C were obtained. Regeneration of exhausted L-Cyst-FeO NPs and recovery of Pb/Cr were demonstrated using 0.01 M HNO and NaOH. L-Cyst-FeO NPs stability and reusability were also demonstrated.
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http://dx.doi.org/10.1038/s41598-017-03380-xDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5550514PMC
August 2017

Amino acid functionalized ZrO nanoparticles decorated reduced graphene oxide based immunosensor.

J Mater Chem B 2017 Mar 24;5(10):2019-2033. Epub 2017 Feb 24.

Special Centre for Nanoscience, Jawaharlal Nehru University, New Delhi-110067, India.

Here, a study is reported on a simple, one-step method for the synthesis of a zirconium dioxide-reduced graphene oxide (ZrO-RGO) nanocomposite involving the reduction of graphene oxide (GO) and in situ growth of ZrO NPs using hydrazine as a reducer. This ZrO-RGO nanocomposite was functionalized with l-methionine (Meth) for immunosensor application. Morphological and structural studies clearly indicated that ZrO NPs (6 nm) were decorated onto the RGO sheets, and enhanced exfoliation, thereby preventing the restacking of the RGO sheets. RGO improved the electrochemical properties of the ZrO-RGO nanocomposite and minimized the aggregation of ZrO NPs. FTIR studies confirmed the functionalization of the ZrO-RGO nanocomposite with Meth and biomolecules (anti-OTA and BSA). The Meth functionalized ZrO-RGO nanocomposite had enhanced biocompatibility and wettability as confirmed by MTT assay and contact angle studies, respectively. Furthermore, a uniform thin film of the Meth/ZrO-RGO nanocomposite was electrophoretically deposited onto an indium tin oxide (ITO) coated glass substrate and utilized for covalent immobilization of monoclonal antibodies specific to ochratoxin A (anti-OTA) for the detection of ochratoxin A (OTA). The fabricated BSA/anti-OTA/Meth/ZrO-RGO/ITO immunoelectrode exhibited a wide linear detection range of 1-20 ng mL with a sensitivity of 4.8 μA ng mL cm and a detection limit of 0.079 ng mL for OTA detection.
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http://dx.doi.org/10.1039/c6tb02594cDOI Listing
March 2017

Self-healing gelatin ionogels.

Int J Biol Macromol 2017 Feb 28;95:603-607. Epub 2016 Nov 28.

School of Physical Sciences, Jawaharlal Nehru University, New Delhi, India; Special Centre for Nanosciences, Jawaharlal Nehru University, New Delhi, India. Electronic address:

We demonstrate room temperature (20°C) self-healing, and substantial recovery (68-96%) of gel rigidity of gelatin, a polypeptide, ionogels (made in 1-ethyl-3-methylimidazolium chloride ionic liquid (IL) solutions via thermal treatment, IL≤5% (w/v)) after they were cut using a surgical blade. The recovery process did not require any stimuli, and the complete healing under ambient condition required about 10h.The self-healing owed its origin to the reformation of network structures via imidazolium ion mediated charge quenching of deprotonated residues, and hydrophobic interaction between neighbouring alkyl tails of IL molecules. The rate of healing determined from the growth of rigidity modulus was 20±5 mPa/s independent of ionic liquid content of the gel. This was true regardless of the fact that ionogels containing more IL had a lower gel modulus due to propensity of hydrophobic linkages, but these were agile enough to recover their network structures to a higher degree during the healing process. These features indicate that the gelatin ionogel being biocompatibile, and biodegradable holds great potential for applications in the field of biomedical engineering.
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http://dx.doi.org/10.1016/j.ijbiomac.2016.11.103DOI Listing
February 2017

L-cysteine capped lanthanum hydroxide nanostructures for non-invasive detection of oral cancer biomarker.

Biosens Bioelectron 2017 Mar 8;89(Pt 2):1042-1052. Epub 2016 Oct 8.

Special Centre for Nanosciences, Jawaharlal Nehru University, New Delhi 110067, India. Electronic address:

In this paper, we present the result of studies related to the in situ synthesis of amino acid (L-Cysteine) capped lanthanum hydroxide nanoparticles [Cys-La(OH) NPs] towards the fabrication of efficient immunosensor for non-invasive detection of oral cancer. The characterization of Cys-La(OH) NPs was carried out by different techniques including X-ray diffraction, scanning electron microscopy, transmission electron microscopy, fourier transform infrared spectroscopy and electrochemical techniques. These Cys-La(OH) NPs were electrophoretically deposited onto an indium-tin-oxide glass substrate and used for immobilization of anti-cytokeratin fragment-21-1 (anti-Cyfra-21-1) for the electrochemical detection of Cyfra-21-1. This immunosensor shows a broad detection range of 0.001-10.2ngmL, the low detection limit of 0.001ngmL, and high sensitivity of 12.044µA (ng per mL cm) with a response time of 5min. This immunosensor was found to be more advanced in terms of high sensitivity and low detection limit as compared to previously reported biosensors and commercially available ELISA kit (Kinesis DX).
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http://dx.doi.org/10.1016/j.bios.2016.10.020DOI Listing
March 2017

Bismuth oxide nanorods based immunosensor for mycotoxin detection.

Mater Sci Eng C Mater Biol Appl 2017 Jan 13;70(Pt 1):564-571. Epub 2016 Sep 13.

DST Centre for Biomolecular Electronics, CSIR-National Physical Laboratory, K.S. Krishnan Marg, New Delhi, India; Department of Biotechnology, Delhi Technological University, Shahbad Daulatpur, Main Bawana Road, Delhi 110042, India. Electronic address:

We report results of the studies relating to fabrication of an efficient immunosensor based on bismuth oxide nanorods (nBiO), electrophoretically deposited onto indium-tin-oxide (ITO) coated glass substrate. This immunosensor was fabricated by immobilization of anti-aflatoxin monoclonal antibodies (Ab-AFB1) and bovine serum albumin (BSA) for aflatoxin B1 detection. The structural and morphological studies of n-BiO have been carried out by XRD, UV-vis spectrophotometer; SEM, AFM and FTIR. It was found that the nBiO provided improved sensing characteristics to the electrode interface in terms of electroactive surface area, diffusion coefficient, charge transfer rate constant and electron transfer kinetics. The results of electrochemical response studies of this BSA/Ab-AFB1/nBiO/ITO immunosensor revealed good linearity in the range of 1-70ngdL with low detection limit of 8.715ng/dL, improved sensitivity of 1.132μA/(ng/dLcm), regression coefficient R of 0.918 and reproducibility of >11 times. The association constant for the BSA/Ab-AFB1/nBiO/ITO immunosensor was determined as 7.318ng/dL.
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http://dx.doi.org/10.1016/j.msec.2016.09.027DOI Listing
January 2017

Mesoporous polyaniline nanofiber decorated graphene micro-flowers for enzyme-less cholesterol biosensors.

Nanotechnology 2016 Aug 15;27(34):345101. Epub 2016 Jul 15.

Inter University Accelerator Centre (IUAC), New Delhi, India.

In the present work, we have studied a nanocomposite of polyaniline nanofiber-graphene microflowers (PANInf-GMF), prepared by an in situ rapid mixing polymerization method. The structural and morphological studies of the nanocomposite (PANInf-GMF) were carried out by scanning electron microscopy, transmission electron microscopy, Fourier transform infrared (FTIR) and Raman spectroscopy. The mesoporous, nanofibrous and microflower structures were observed by scanning electron microscopy. The functional groups and synergetic effects were observed by FTIR and micro-Raman measurements. The water wettability was carried out by a contact angle measurement technique and found to be super hydrophilic in nature towards water. This nanocomposite was deposited onto indium-tin-oxide coated glass substrate by a drop casting method and used for the detection of cholesterol using an electrochemical technique. The differential pulse voltammetry studies show the appreciable increase in the current with the addition of 1.93 to 464.04 mg dl(-1) cholesterol concentration. It is also found that the electrodes were highly selective towards cholesterol when compared to other biological interfering analytes, such as glucose, urea, citric acid, cysteine and ascorbic acid. The sensitivity of the sensor is estimated as 0.101 μA mg(-1) dl cm(-2) and the lower detection limit as 1.93 mg dl(-1). This work will throw light on the preparation of non-enzymatic biosensors based on PANInf-carbon nanostructure composites.
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http://dx.doi.org/10.1088/0957-4484/27/34/345101DOI Listing
August 2016

Immunosensor based on nanocomposite of nanostructured zirconium oxide and gelatin-A.

Int J Biol Macromol 2016 Jan 26;82:480-7. Epub 2015 Oct 26.

Special Centre for Nanosciences, Jawaharlal Nehru University, New Delhi 110067, India. Electronic address:

We have reported the studies related to the fabrication of a nanocomposite, comprising of sol-gel derived inorganic zirconium oxide nanoparticles (ZrO2 NPs) and organic biopolymer gelatin-A (GA), deposited on indium-tin-oxide (ITO) coated glass substrate by drop casting method. The GA-ZrO2/ITO electrode was used for immobilization of monoclonal antibodies (Ab) specific to antigen Vibrio cholerae (Vc) followed by bovine serum albumin (BSA) for antigen Vc detection using electrochemical techniques. The structural and morphological behaviour of these ZrO2 NPs, GA-ZrO2/ITO electrode and BSA/Ab/GA-ZrO2/ITO immunosensor was characterized by scanning electron microscopy and Fourier transform infrared spectroscopy techniques. The transmission electron microscopy study exhibited a spherical shape ZrO2 NPs. The average crystalline size of ZrO2 NPs was obtained as 10.3 ± 1 nm from X-ray diffraction measurement and 72 nm hydrodynamic radius measured by dynamic light scattering. GA-ZrO2 nanocomposite provides a porous structure which assists to higher loading of Ab on the matrix surface that improved the biosensing properties. The electrochemical response studies of the fabricated BSA/Ab/GA-ZrO2/ITO immunosensor exhibited good linearity in the range of 50-400 ng mL(-1), low limit of detection of 0.74 ng/mL, sensitivity as 0.03 Ω ng(-1)mL(-1)cm(-2) and reproducibility more than 10 times.
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http://dx.doi.org/10.1016/j.ijbiomac.2015.10.074DOI Listing
January 2016

Internal structure and thermo-viscoelastic properties of agar ionogels.

Carbohydr Polym 2015 Dec 31;134:617-26. Epub 2015 Jul 31.

School of Physical Sciences, Jawaharlal Nehru University, New Delhi, India; Special Centre for Nanosciences, Jawaharlal Nehru University, New Delhi, India. Electronic address:

Ionic liquids (IL) can alter the physical properties of agar hydrogels. Rheology studies show that gels with wide range of storage moduli (gel strength) G0 values ranging from 1 to 20 KPa could be made in imidazolium based IL solutions where the IL concentration may not exceed 5% (w/v). Gelation and gel melting temperatures (tgel and Tm) could be altered by as much as ≈ 10 °C. Small angle neutron scattering studies revealed the presence of fibre bundles of agar double helices having typical length of 120 nm that increased to ≈ 180 nm under favorable conditions. These structures gain flexibility from the cladding of the agar bundles by IL molecules which in turn caused partial charge neutralization of its surface. Raman spectroscopy revealed differential hydration of these bundles. It was found that IL molecules with longer alkyl chain (more hydrophobic) altered the gel homogeneity, and changed its thermal and mechanical properties significantly. Therefore, customization of agar hydrogels in green solvent medium (IL solutions) widens the scope of its application potential that may include sensing.
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http://dx.doi.org/10.1016/j.carbpol.2015.07.094DOI Listing
December 2015

A chitosan modified nickel oxide platform for biosensing applications.

J Mater Chem B 2015 Aug 27;3(32):6698-6708. Epub 2015 Jul 27.

Special Centre for Nanosciences, Jawaharlal Nehru University, New Delhi-110067, India.

We present a highly sensitive and selective electrochemical sandwich immunosensor (the analyte is "sandwiched" between two antibodies) based on chitosan (CH) modified nickel oxide (NiO) nanoparticles for the detection of Vibrio cholerae (Vc). The primary monoclonal antibodies specific to Vibrio cholerae (Ab-Vc) and bovine serum albumin (BSA) were co-immobilized on a CH-NiO surface deposited onto an indium tin oxide (ITO) coated glass electrode. The specific binding of Ab-Vc towards Vc was confirmed by interaction of secondary antibodies conjugated with protein [horse radish peroxidase (HRP)], with varying concentrations of hydrogen peroxide (HO), via electrochemical as well as optical techniques. The CH-NiO/ITO and Ab-Vc/CH-NiO/ITO electrodes have been characterized using X-ray diffraction, Fourier transform infrared spectroscopy, scanning electron microscopy, high-resolution transmission electron microscopy and electrochemical techniques. This immunoelectrode (BSA/Ab-Vc/CH-NiO/ITO) exhibits a detection range of 20-700 ng mL with a sensitivity of 0.644 μA ng mL cm and a low detection range of 0.108 ng mL to Vc concentration. Besides this, the electrochemical response of the sandwich immunosensor (HRP-Ab-Vc/Vc/BSA/Ab-Vc/CH-NiO/ITO) towards HO concentration is found to be linear in the range of 10-50 mM with excellent sensitivity (2.95 mA mM cm).
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http://dx.doi.org/10.1039/c5tb00494bDOI Listing
August 2015

Antibacterial and Antifungal Activity of Biopolymers Modified with Ionic Liquid and Laponite.

Appl Biochem Biotechnol 2015 Sep 5;177(1):267-77. Epub 2015 Jul 5.

Polymer and Biophysics Laboratory, School of Physical Sciences, Jawaharlal Nehru University, New Delhi, 110067, India.

In the present study, the antimicrobial properties of modified biopolymers such as gelatin and agar have been investigated. These biopolymers (agar and gelatin) are modified by dissolving in ionic liquid (IL) [1-ethyl-3-methylimidazolium chloride ([C2mim][Cl]) and 1-octyl-3-methyl imidazolium chloride ([C8mim][Cl])] solutions. It was noticed that agar-ionogel (Ag-IL), gelatin-ionogel (GB-IL), and gelatin organogel (gelatin-glycerol solution along with laponite, nanoclay) nanocomposite (GA-NC) formed are highly stable, optically clear, and transparent without any air bubbles. The antimicrobial activity of these (Ag-IL), (GB-IL), and GA-NC were analyzed for both gram-negative (Escherichia coli, Klebsiella pneumoniae) and gram-positive bacterial strains (Staphylococcus aureus and Staphylococcus pyogenes) and fungus A. niger, C. albicans. Antibacterial and antifungal activity studies were carried out at different dilutions such as 100, 99, and 90 % (v/v). It was found that Ag-IL, GB-IL, and individual IL ([C8mim][Cl]) exhibited superior antimicrobial activities, indicating that longer IL chain enhance the cell membrane permeability of S. aureus, S. pyogenes, and E. coli cells. However, GA-NC nanocomposite and [C2mim][Cl]-based composites does not exhibit any bacterial inhibition activity for all bacterial strains.
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http://dx.doi.org/10.1007/s12010-015-1727-7DOI Listing
September 2015

Oxalic acid capped iron oxide nanorods as a sensing platform.

Chem Biol Interact 2015 Aug 3;238:129-37. Epub 2015 Jun 3.

Special Centre for Nanosciences, Jawaharlal Nehru University, New Delhi 110067, India. Electronic address:

A label free impedimetric immunosensor has been fabricated using protein bovine serum albumin (BSA) and monoclonal antibodies against Vibrio cholerae (Ab) functionalized oxalic acid (OA) capped iron oxide (Fe3O4) nanorods for V. cholerae detection. The structural and morphological studies of Fe3O4 and OA-Fe3O4, were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), Fourier transform infrared (FTIR) spectroscopy and dynamic light scattering (DLS) techniques. The average crystalline size of Fe3O4, OA-Fe3O4 nanorods were obtained as about 29±1 and 39±1nm, respectively. The hydrodynamic radius of nanorods is found as 116nm (OA-Fe3O4) and 77nm (Fe3O4) by DLS measurement. Cytotoxicity of Fe3O4 and OA-Fe3O4 nanorods has been investigated in the presence of human epithelial kidney (HEK) cell line 293 using MTT assay. The cell viability and proliferation studies reveal that the OA-Fe3O4 nanorods facilitate cell growth. The results of electrochemical response studies of the fabricated BSA/Ab/OA-Fe2O3/ITO immunosensor exhibits good linearity in the range of 12.5-500ng mL(-1) with low detection limit of 0.5ng mL(-1), sensitivity 0.1Ωng(-1)ml(-1)cm(-2) and reproducibility more than 11 times.
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http://dx.doi.org/10.1016/j.cbi.2015.05.020DOI Listing
August 2015
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