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Priyadarshini E, Minzar M, Pandey S, Rawat K. Synergistic reduction of nitrophenols by Au-CDs nanoconjugates with NaBH 4. Nanotechnology 2024; 35:275101. [PMID: 38502954 DOI: 10.1088/1361-6528/ad355a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/15/2023] [Accepted: 03/19/2024] [Indexed: 03/21/2024]
Abstract
Developing sustainable and innovative approaches for the efficient reduction of nitrophenols is crucial for environmental remediation, for managing health concerns posed by their widespread presence as hazardous pollutants in industrial effluents and contaminated water. We report the use of 12.9 ± 1 nm (TEM data) sized gold carbon dot nanoconjugates (Au@CDs) for catalytic conversion of o, m, p-nitrophenols to aminophenols by sodium borohydride. A simple approach was followed to synthesize ultra-small and highly stable Au@CDs, using citric acid and PEG as reducing and stabilizing agents. X-ray diffraction analysis verified the formation of nano-crystalline nanoconjugates. These nanoconjugates showed a remarkable catalytic activity in the range of 0.22-0.33 s-1(varying with nanoconjugate concentration) which was much higher compared to conventional chemical methods of reduction. All the catalytic reaction experiments were performed at room temperature (27 ± 2 °C). Furthermore, an increase in rate constant was observed with increasing concentration of nanoconjugates. The catalytic activity of Au@CDs nanoconjugates was observed to be in order of m-nitrophenol > o-nitrophenol > p-nitrophenol with apparent rate constant (kaap) values of 0.068, 0.043 and 0.031, respectively. Comparative analysis with GNPs, CDs and Au@CDs nanoconjugates stated that the nanoconjugates had superior catalytic activity. The research can have significant implications in the development of new strategies for environmental remediation and biomedical applications.
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Affiliation(s)
| | - Mohd Minzar
- Department of Chemistry, School of Chemical and Life Sciences, Jamia Hamdard, New Delhi, India
| | - Saurabh Pandey
- Department of Biochemistry, School of Chemical and Life Sciences, Jamia Hamdard, New Delhi, India
| | - Kamla Rawat
- Department of Chemistry, School of Chemical and Life Sciences, Jamia Hamdard, New Delhi, India
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Priyadarshini E, Minzar M, Pandey S, Rawat K. Biocompatible gelatin/carbon dot nanocomposite based urea sensor and the effect of nitrogen ion implantation. Biochem Biophys Res Commun 2023; 675:99-105. [PMID: 37463525 DOI: 10.1016/j.bbrc.2023.06.081] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2023] [Revised: 06/07/2023] [Accepted: 06/26/2023] [Indexed: 07/20/2023]
Abstract
In this study, we have fabricated a novel platform for sensing of urea using gelatin/carbon dots nanocomposite system. The sensor electrode was created by depositing the nanocomposite gel onto thin glass plates coated with indium tin oxide (ITO) using the drop casting technique. The behavior of these electrodes was investigated against a number of bioanalytes in the concentration range of 2-20 mM by cyclic voltammetry. The system was observed to be highly selective for urea with a sensitivity of 1.65 μA/mM/cm in the experimental linear range of 2-20 mM. Furthermore, the gelatin/CD-ITO electrode were also subjected to 50 KeV N2+ ion beam irradiation with varying fluence in the range of 1012 to 1016 ions/cm2. Sensing profile of the irradiated samples for urea suggested enhancement in sensitivity to 2 μA/mM cm2, when the ion fluence was 5 × 1015 ions/cm2. This enhancement after irradiation suggests a clear dependence of detection on the fluence of the ion beam. The observed excellent sensitivity of radiation processed nanocomposite material can be used as an enzyme-free platform for urea detection. Additionally, the CDs showed fluorescence quenching on treatment with mere 50 μM urea suggesting the high sensitivity of the platform.
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Affiliation(s)
| | - Mohd Minzar
- Department of Chemistry, School of Chemical and Life Sciences, Jamia Hamdard, New Delhi, India
| | - Saurabh Pandey
- Department of Biochemistry, School of Chemical and Life Sciences, Jamia Hamdard, New Delhi, India.
| | - Kamla Rawat
- Department of Chemistry, School of Chemical and Life Sciences, Jamia Hamdard, New Delhi, India.
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Das K, Bhatt N, Parambil AM, Kumari K, Kumar R, Rawat K, Rajamani P, Bohidar HB, Nadeem A, Muthupandian S, Meena R. Divergent Responses of Hydrophilic CdSe and CdSe@CdS Core-Shell Nanocrystals in Apoptosis and In Vitro Cancer Cell Imaging: A Comparative Analysis. J Funct Biomater 2023; 14:448. [PMID: 37754862 PMCID: PMC10531721 DOI: 10.3390/jfb14090448] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2023] [Revised: 08/03/2023] [Accepted: 08/04/2023] [Indexed: 09/28/2023] Open
Abstract
With their distinctive core-shell design, core-shell nanocrystals have drawn interest in catalysis, medicinal research, and nanotechnology. These nanocrystals have a variety of characteristics and possible uses. The application of core-shell nanocrystals offers significant potential in increasing diagnostic and therapeutic approaches for cancer research in apoptosis and in vitro cancer cell imaging. In the present study, we investigated the fluorescence behavior of hydrophilic CdSe (core-only) and CdSe@CdS (core-shell) nanocrystals (NCs) and their potential in cancer cell imaging. The addition of a CdS coating to CdSe NCs increased the fluorescence intensity tenfold. The successful fabrication of core-shell CdSe@CdS nanocrystals was proven by a larger particle size (evaluated via DLS and TEM) and their XRD pattern and surface morphology compared to CdSe (core-only) NCs. When these NCs were used for bioimaging in MCF-7 and HEK-293 cell lines, they demonstrated excellent cellular uptake due to higher fluorescence intensity within cancerous cells than normal cells. Comparative cytotoxicity studies revealed that CdSe NCs were more toxic to all three cell lines (HEK-293, MCF-7, and HeLa) than CdSe@CdS core-shell structures. Furthermore, a decrease in mitochondrial membrane potential and intracellular ROS production supported NCs inducing oxidative stress, which led to apoptosis via the mitochondria-mediated pathway. Increased cytochrome c levels, regulation of pro-apoptotic gene expression (e.g., p53, Bax), and down-regulation of Bcl-2 all suggested cellular apoptosis occurred via the intrinsic pathway. Significantly, at an equivalent dose of core-shell NCs, core-only NCs induced more oxidative stress, resulting in increased apoptosis. These findings shed light on the role of a CdS surface coating in reducing free radical release, decreasing cytotoxicity, and improving fluorescence, advancing the field of cell imaging.
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Affiliation(s)
- Kishan Das
- School of Physical Sciences, Jawaharlal Nehru University, New Delhi 110067, India; (K.D.); (H.B.B.)
- Shaheed Rajguru College of Applied Sciences for Women, University of Delhi, New Delhi 110096, India
| | - Neelima Bhatt
- School of Environment Sciences, Jawaharlal Nehru University, New Delhi 110067, India; (N.B.); (A.M.P.); (R.K.); (P.R.)
| | - Ajith Manayil Parambil
- School of Environment Sciences, Jawaharlal Nehru University, New Delhi 110067, India; (N.B.); (A.M.P.); (R.K.); (P.R.)
| | - Kajal Kumari
- A.I. Virtanen Institute for Molecular Sciences, University of Eastern Finland, 70211 Kuopio, Finland;
| | - Raj Kumar
- School of Environment Sciences, Jawaharlal Nehru University, New Delhi 110067, India; (N.B.); (A.M.P.); (R.K.); (P.R.)
| | - Kamla Rawat
- Department of Chemistry, Jamia Hamdard University, New Delhi 110062, India;
| | - Paulraj Rajamani
- School of Environment Sciences, Jawaharlal Nehru University, New Delhi 110067, India; (N.B.); (A.M.P.); (R.K.); (P.R.)
| | - Himadri B. Bohidar
- School of Physical Sciences, Jawaharlal Nehru University, New Delhi 110067, India; (K.D.); (H.B.B.)
| | - Ahmed Nadeem
- Department of Pharmacology and Toxicology, College of Pharmacy, King Saud University, Riyadh 11451, Saudi Arabia;
| | - Saravanan Muthupandian
- AMR and Nanomedicine Laboratory, Department of Pharmacology, Saveetha Dental College and Hospitals, Saveetha Institute of Medical and Technical Sciences (SIMATS), Chennai 600077, India
| | - Ramovatar Meena
- School of Environment Sciences, Jawaharlal Nehru University, New Delhi 110067, India; (N.B.); (A.M.P.); (R.K.); (P.R.)
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Das K, Meena R, Gaharwar US, Priyadarshini E, Rawat K, Paulraj R, Mohanta YK, Saravanan M, Bohidar HB. Bioaccumulation of CdSe Quantum Dots Show Biochemical and Oxidative Damage in Wistar Rats. Oxidative Medicine and Cellular Longevity 2023; 2023:7707452. [PMID: 37064800 PMCID: PMC10101743 DOI: 10.1155/2023/7707452] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/05/2022] [Revised: 11/24/2022] [Accepted: 01/19/2023] [Indexed: 04/09/2023]
Abstract
Cadmium selenium quantum dots (CdSe QDs) with modified surfaces exhibit superior dispersion stability and high fluorescence yield, making them desirable biological probes. The knowledge of cellular and biochemical toxicity has been lacking, and there is little information on the correlation between in vitro and in vivo data. The current study was carried out to assess the toxicity of CdSe QDs after intravenous injection in Wistar male rats (230 g). The rats were given a single dose of QDs of 10, 20, 40, and 80 mg/kg and were kept for 30 days. Following that, various biochemical assays, hematological parameters, and bioaccumulation studies were carried out. Functional as well as clinically significant changes were observed. There was a significant increase in WBC while the RBC decreased. This suggested that CdSe quantum dots had inflammatory effects on the treated rats. The various biochemical assays clearly showed that high dose induced hepatic injury. At a dose of 80 mg/kg, bioaccumulation studies revealed that the spleen (120 g/g), liver (78 g/g), and lungs (38 g/g) accumulated the most. In treated Wistar rats, the bioretention profile of QDs was in the following order: the spleen, liver, kidney, lungs, heart, brain, and testis. The accumulation of these QDs induced the generation of intracellular reactive oxygen species, resulting in an alteration in antioxidant activity. It is concluded that these QDs caused oxidative stress, which harmed cellular functions and, under certain conditions, caused partial brain, kidney, spleen, and liver dysfunction. This is one of the most comprehensive in vivo studies on the nanotoxicity of CdSe quantum dots.
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Affiliation(s)
- Kishan Das
- Shaheed Rajguru College of Applied Sciences for Women, University of Delhi, New Delhi, India
- School of Physical Sciences, Jawaharlal Nehru University, New Delhi, India
| | - Ramovatar Meena
- School of Environment Sciences, Jawaharlal Nehru University, New Delhi, India
| | - Usha Singh Gaharwar
- School of Environment Sciences, Jawaharlal Nehru University, New Delhi, India
- Swami Shraddhanand College, University of Delhi, Delhi, India
| | | | - Kamla Rawat
- Department of Chemistry, School of Life and Chemical Sciences, Jamia Hamdard, New Delhi, India
| | - R. Paulraj
- School of Environment Sciences, Jawaharlal Nehru University, New Delhi, India
| | - Yugal Kishore Mohanta
- Department of Applied Biology, School of Biological Sciences, University of Science and Technology Meghalaya (USTM), 9th Mile, Baridua-793101, Ri-Bhoi Dist., Meghalaya, India
| | - Muthupandian Saravanan
- Department of Medical Microbiology and Immunology, Division of Biomedical Sciences, School of Medicine, College of Health Sciences, Mekelle University, Tigray, Ethiopia
- AMR and Nanotherapeutics Laboratory, Department of Pharmacology, Saveetha Dental College, Saveetha Institute of Medical and Technical Sciences (SIMATS), Chennai, 600 077 Chennai, India
| | - Himadri B. Bohidar
- School of Physical Sciences, Jawaharlal Nehru University, New Delhi, India
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Priyadarshini E, Pandey S, Rawat K. Gold-carbon dot (Au@Cd) nanoconjugates based electrochemical sensing of cholesterol and effect of nitrogen ion implantation on sensitivity. Biochem Biophys Res Commun 2023; 655:97-103. [PMID: 36934590 DOI: 10.1016/j.bbrc.2023.03.013] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2023] [Revised: 02/20/2023] [Accepted: 03/06/2023] [Indexed: 03/09/2023]
Abstract
Serum cholesterol dysregulation is associated with prognosis and diagnosis of many diseases and effective biosensor will improvise their management. A novel electrochemical biosensor was fabricated based on gelatin-Au@CD nanoconjugate films for cholesterol detection. Initially, the surface of indium titanium oxide (ITO) coated glass was modified by drop casting of gelatin-Au@CD nanoconjugates to prepare the electrodes. Electrochemical studies for detection of bioanalytes(such as urea (U), ascorbic acid (AA), oxalic acid (OA), gallic acid (GA), cholesterol (Chox), dextrose (D), l-cysteine (Cys) and citric acid (CA)) were performed using cyclic voltammetry. The presence of nanoconjugates provided an appropriate environment for enhanced electrochemical response for cholesterol. These electrodes exhibited a linear response towards the presence of cholesterol in the linear concentration range of 2-20 mM with a correlation coefficient of 0.95, and the superior sensitivity of 1.36 μA/mM/cm2. Additionally, enhanced sensitivity (2.99 μA/mM/cm2) of nitrogen ion irradiated films up to a fluence of 1016 ions/cm2 was noticed because of morphological changes in the electrode surface brought about by irradiation. Approximately 54% enhancement was found when the ion fluence was 1016 ions/cm2. The designed nanoconjugate electrode showed excellent response towards cholesterol sensing and eliminates the requirement of any enzymes making the overall process simpler, cost-effective and allows for room temperature storage.
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Affiliation(s)
| | - Saurabh Pandey
- Department of Biochemistry, School of Chemical and Life Sciences, Jamia Hamdard, New Delhi, India.
| | - Kamla Rawat
- Department of Chemistry, School of Chemical and Life Sciences, Jamia Hamdard, New Delhi, India.
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Sharma S, Rawat K, Bohidar HB. Role of Nanomedicines in Controlling Malaria: A Review. Curr Top Med Chem 2023; 23:1477-1488. [PMID: 37073152 DOI: 10.2174/1568026623666230417083401] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2022] [Revised: 02/21/2023] [Accepted: 02/27/2023] [Indexed: 04/20/2023]
Abstract
Malaria has created havoc since time immemorial. It has actually become a major health concern due to its high prevalence in developing countries where poor sanitary conditions facilitate the seasonal breeding of the vector, the female Anopheles mosquito. Even after tremendous advancements in pest control and pharmacology science, managing this disease has not been successful, and the cure for this deadly infection has not proven effective lately. The various conventional drugs used are chloroquine, primaquine, mefloquine, atovaquone, quinine, artemisinin etc. All of these have one or other major disadvantages like multi-drug resistance, high dose requirements, aggravated toxicity, non-specificity of conventional drugs, and the emergence of drug-resistant parasites. Therefore, it is necessary to surpass these limitations and look for an alternative to curb the spread of this disease using an emerging technology platform. Nanomedicine is showing promise as an effective alternative tool for the management of malaria. The idea of this tool resonates well with David J. Triggle's outstanding suggestion "The chemist is as the astronaut, searching for biologically useful space in the chemical universe. This review presents a detailed discussion on various nanocarriers, their mode of action and future perspective in treating malaria. Nanotechnology-based drug delivery methods are highly specific, require a lower dose, offer more bioavailability with prolonged drug release and stay in the body longer. Recent nano drug encapsulation and delivery vehicles comprise nanocarriers like liposomes, and organic and inorganic nanoparticles, emerging as promising alternatives for malaria management.
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Affiliation(s)
- Sakshi Sharma
- Department of Chemistry, Jamia Hamdard, New Delhi, 110062, India
| | - Kamla Rawat
- Department of Chemistry, Jamia Hamdard, New Delhi, 110062, India
| | - Himadri B Bohidar
- School of Physical Sciences, Jawaharlal Nehru University, New Delhi, India
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Rais, Rais A, Rawat K, Prasad T, Bohidar HB. Boron-doped carbon quantum dots: a 'turn-off' fluorescent probe for dopamine detection. Nanotechnology 2020; 32:025501. [PMID: 33055372 DOI: 10.1088/1361-6528/abb84d] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Boron-doped carbon quantum dots (size 2.3 nm) were fabricated by a modified hydrothermal carbonization one-pot synthesis protocol using 4-hydroxy phenylboronic acid as the common precursor that provided seed for the formation of carbon quantum dots as well as the dopant. These quantum dots exhibited excellent properties, namely good aqueous dispersion, strong fluorescence emission, good environmental stability, high selectivity and sensitivity towards the neurochemical dopamine even in the absence of any linker, functionalizing agents or enzyme. It is shown that this material can be used as a 'turn-off' fluorescent probe for the detection of even low concentrations of dopamine with a limit of detection (3σ/S) of about 6 μM. The simplicity of the synthesis protocol and the ease of dopamine detection define the novelty of this approach.
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Affiliation(s)
- Rais
- Department of Chemistry, School of Life and Chemical Sciences, Jamia Hamdard, New Delhi, India. School of Physical Sciences, Jawaharlal Nehru University, New Delhi, India
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Pandey PK, Preeti, Rawat K, Prasad T, Bohidar HB. Multifunctional, fluorescent DNA-derived carbon dots for biomedical applications: bioimaging, luminescent DNA hydrogels, and dopamine detection. J Mater Chem B 2020; 8:1277-1289. [PMID: 31967170 DOI: 10.1039/c9tb01863h] [Citation(s) in RCA: 34] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Here, we describe the synthesis of 2-3 nm, hydrophilic, blue fluorescence-emitting carbon dots (C-Dots, made using a DNA precursor) by the hydrothermal route from the gelling concentration of 2% (w/v) DNA. These dots exhibited highly efficient internalization in pathogenic fungal cells, negligible cytotoxicity, good PL stability, and high biocompatibility, thus demonstrating their potential as nanotrackers in microbial studies. Bioimaging was performed using Candida albicans as the representative for microbial pathogens. The novelty of these dots is that they formed fluorescent nanocomposite hydrogels with the same DNA much below the gelation concentration (1% w/v) and the tunable gels possessed strength between 20 and 80 Pa with the corresponding gelation temperature Tgel between 40 to 50 °C. The network density and gelation free energy data supported the superior crosslinking ability of these dots. The as-prepared hydrogels can replace the existing toxic quantum dot-based hydrogels for drug delivery. We also demonstrated the use of a DNA hydrogel-fabricated working electrode (DNA-C-Dot/ITO electrode) for the biosensing of dopamine. Our electrochemical biosensor had a detection limit of 5 × 10-3 mM for dopamine. These multifunctional, fluorescent C-Dots and hydrogel after suitable conjugation or loading with molecules and drugs hold promising potential for further exploitation in bioimaging, targeted drug delivery, wound healing, and biosensing applications.
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Affiliation(s)
| | - Preeti
- Special Centre for Nanoscience, Jawaharlal Nehru University, New Delhi, India.
| | - Kamla Rawat
- Department of Chemistry, School of Chemical and Life Science, Jamia Hamdard, New Delhi, India
| | - Tulika Prasad
- Special Centre for Nanoscience, Jawaharlal Nehru University, New Delhi, India. and Advanced Instrumentation Research and Facility, Jawaharlal Nehru University, New Delhi, India
| | - H B Bohidar
- School of Physical Sciences, Jawaharlal Nehru University, New Delhi, India. and Special Centre for Nanoscience, Jawaharlal Nehru University, New Delhi, India.
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Priyadarshini E, Rawat K, Bohidar HB, Rajamani P. Dual-probe (colorimetric and fluorometric) detection of ferritin using antibody-modified gold@carbon dot nanoconjugates. Mikrochim Acta 2019; 186:687. [PMID: 31595370 DOI: 10.1007/s00604-019-3802-1] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2019] [Accepted: 09/07/2019] [Indexed: 10/25/2022]
Abstract
A dual-mode assay is described for immunological determination of the anemia biomarker ferritin. It is based on the use of a gold@carbon dot (Au@CD) nanoconjugate as a colorimetric and fluorescent probe. Au@CD is hydrophilic, easily surface modified and stable in aqueous solution. The Au@CD have a red color with blue-green fluorescence and were modified with antibody against ferritin. This allows bi-modal detection of ferritin. Assays can be performed in phosphate buffer and were also analyzed in (Bovine Serum Albumin) BSA and (Fetal Bovine Serum) FBS. Detection is based on antigen-antibody interaction underlying the classical sandwich model. Response to ferritin can be detected by spectrophotometry (at 570 nm) or fluorescence (at excitation/emission maxima of 354/454 nm). Under optimal conditions, the assay has a linear response in the 1 to 120 ngmL-1 ferritin concentration range and detection limits of 20 ng (colorimetrically) and 64 ng (fluorometrically). Graphical abstract Schematic representation of the function of the designed nanoprobe. The Au@CD nanoconjugates are functionalized with ferritin antibody in the initial step which specifically interacts with ferritin molecules leading to aggregation and subsequent changes in the optical and fluorescence signals.
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Affiliation(s)
- Eepsita Priyadarshini
- School of Environmental Sciences, Jawaharlal Nehru University, New Delhi, 110067, India
| | - Kamla Rawat
- Department of Chemistry, School of Chemical and Life Sciences, Jamia Hamdard, New Delhi, 110062, India
| | - Himadri B Bohidar
- School of Physical Sciences, Jawaharlal Nehru University, New Delhi, 110067, India.,Special Centre for Nano Sciences, Jawaharlal Nehru University, New Delhi, 110067, India
| | - Paulraj Rajamani
- School of Environmental Sciences, Jawaharlal Nehru University, New Delhi, 110067, India.
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Sukumaran A, Das K, Rawat K, Bohidar HB. Universal Validity of Einstein Relation and Size-Dependent Viscosity and Surface-Active Characteristics of Nanofluids. Int J Nanosci 2018. [DOI: 10.1142/s0219581x18500060] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
In this report, the general validity of the Einstein viscosity relation, [Formula: see text], [Formula: see text], ratio of solution to solvent viscosity), is examined in nanofluids where monodisperse spherical nanoparticles (polystyrene latex spheres) of size 50–400[Formula: see text]nm were dispersed in water at room temperature, 25[Formula: see text]C. In addition to viscosity, we also measured contact angle, [Formula: see text], and surface free-energy, [Formula: see text], as function of particle concentration and observed that the universal relation [Formula: see text], [Formula: see text], remained valid, where [Formula: see text] may be relative viscosity, contact angle or surface free-energy and [Formula: see text] is a shape-dependent constant and is 2.5 in the Einstein limit. Thus, the Einstein relation has a wider validity than is generally thought encompassing both bulk and surface properties of nanofluids. Furthermore, we extend the study to establish an empirical relation between intrinsic viscosity [[Formula: see text]] and Huggins interaction parameter [Formula: see text], with particle size [Formula: see text], which obeyed: [Formula: see text] or [Formula: see text], where [Formula: see text] is in nm, [[Formula: see text]] is in cc/g, [Formula: see text] is in (g/cc)2 and [Formula: see text], [Formula: see text] and [Formula: see text] are constants of particle size. Identical expressions could be established for contact angle and surface free energy. These remarkable observations have not been reported hitherto.
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Affiliation(s)
- Arya Sukumaran
- School of Physical Sciences, Jawaharlal Nehru University, New Delhi 110067, India
| | - Kishan Das
- School of Physical Sciences, Jawaharlal Nehru University, New Delhi 110067, India
| | - Kamla Rawat
- Special Center for Nanosciences, Jawaharlal Nehru University, New Delhi 110067, India
- Inter University Accelerator Centre, New Delhi 110067, India
| | - H. B. Bohidar
- School of Physical Sciences, Jawaharlal Nehru University, New Delhi 110067, India
- Special Center for Nanosciences, Jawaharlal Nehru University, New Delhi 110067, India
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Kaushik P, Rawat K, Aswal VK, Kohlbrecher J, Bohidar HB. Mixing ratio dependent complex coacervation versus bicontinuous gelation of pectin with in situ formed zein nanoparticles. Soft Matter 2018; 14:6463-6475. [PMID: 30051132 DOI: 10.1039/c8sm00809d] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
We report on the competitive phenomenon of complex coacervation versus bicontinuous gelation between pectin (P, a polyanionic carbohydrate, [P] = 0.01-2% (w/v)) and zein nanoparticles (Z, a hydrophobic protein and a weak polyampholyte, [Z] = 0.1 and 0.5% (w/v), in an ethanolic solution of effective concentration 4 and 27% (v/v)), which was studied below (pH ≈ 4), and above (pH ≈ 7.4) the pI (≈ 6.2) of zein at room temperature, 25 °C. The uniqueness of this study arises from the interaction protocol used, where the pectin used was in the extended polyelectrolyte (persistence length ≈ 10 nm) conformation while zein was used as a charged globular nanoparticle (size ≈ 80-120 nm) that was formed in situ. Their mixing ratio, r = [P] : [Z] (w/w), was varied from 0.02 to 4.0 (for [Z] = 0.5% (w/v)), and from 0.1 to 7.5 (for [Z] = 0.1% (w/v)) in the ionic strength range 10-4 to 10-2 M NaCl. Zeta potential data revealed that at pH ≈ 4, the complementary binding condition, r = 1 : 1 (equivalent to 1 : 5 molecule/nanoparticle) demarcated the coacervate from the gel region. The measured rigidity (G0, low frequency storage modulus) of these materials revealed the following: for r < 1, (low pectin content samples, coacervate region) the material had lower values of Gcoac0, whereas for r > 1, an excess of pectin facilitated gelation with Ggel0 ≫ Gcoac0. Above pI, surface patch binding caused associative interactions and complex coacervation though both biopolymers had similar net charge. The network density was used as a descriptor to distinguish between the coacervate and gel samples. Their microstructures were probed by small angle neutron scattering (SANS), and viscoelastic properties by rheology. Simple modeling shows that formation of the interpolymer complex was favored in higher protein containing samples. Mixing ratio dependent selective coacervation (a kinetic process) and bicontinuous gelation (a thermodynamic process) are rarely seen to coexist in biopolymer interactions.
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Affiliation(s)
- Priyanka Kaushik
- School of Physical Sciences, Jawaharlal Nehru University, New Delhi 110067, India.
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Mir IA, Radhakrishanan VS, Rawat K, Prasad T, Bohidar HB. Bandgap Tunable AgInS based Quantum Dots for High Contrast Cell Imaging with Enhanced Photodynamic and Antifungal Applications. Sci Rep 2018; 8:9322. [PMID: 29921973 PMCID: PMC6008435 DOI: 10.1038/s41598-018-27246-y] [Citation(s) in RCA: 51] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2017] [Accepted: 05/25/2018] [Indexed: 12/31/2022] Open
Abstract
Herein, we report a facile microwave-assisted synthesis of cadmium-free water-soluble silver indium sulfide (AgInS2 or AIS) and AgInS@ZnS (or AIS@ZnS) core-shell quantum dots (QDs) using glutathione (GSH) as stabilizer. The core and core-shell nanocrystals exhibit tunable bandgap ranging of 2.3-3.1 and 2.4-3.5 eV, mean particle size of 2.5 and 3.25 nm, quantum yield of 26% and 49%, and fluorescence lifetimes of 326 and 438 ns, respectively. The core-shell QDs exhibit color-tunable emission in the visible region (500 to 600 nm), where the tunability was achieved by varying the molar ratio of Ag:In in the precursors. In vitro evaluation of antifungal activity of these water/ buffer stable QDs against the fungal pathogen, Candida albicans demonstrated that these were not toxic to the fungal cells upto a concentration of 100 µg/ml for 16 hours of incubation. Confocal imaging and spectrofluorometric studies showed enhanced fluorescence inside the microbial cells suggesting that AIS@ZnS particles had the capability to easily penetrate the cells. The increased generation of reactive oxygen species was evaluated for the core-shell QDs (photosensitizers) by using 9, 10-anthracenediyl-bis(methylene)dimalonic acid (ABMDMA) as singlet oxygen (1O2) scavenger molecule. These QDs have the potential for use as high contrast cell imaging, photodynamic and antifungal agents.
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Affiliation(s)
- Irshad Ahmad Mir
- School of Physical Sciences, Jawaharlal Nehru University, New Delhi, India
| | - V S Radhakrishanan
- Advanced Instrument Research Facility, Jawaharlal Nehru University, New Delhi, India
| | - Kamla Rawat
- Special Centre for Nano Sciences, Jawaharlal Nehru University, New Delhi, India
- Inter University Accelerator Centre, New Delhi, India
| | - Tulika Prasad
- Advanced Instrument Research Facility, Jawaharlal Nehru University, New Delhi, India.
- Special Centre for Nano Sciences, Jawaharlal Nehru University, New Delhi, India.
| | - H B Bohidar
- School of Physical Sciences, Jawaharlal Nehru University, New Delhi, India.
- Special Centre for Nano Sciences, Jawaharlal Nehru University, New Delhi, India.
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Pandey PK, Rawat K, Aswal V, Kohlbrecher J, Bohidar H. Imidazolium based ionic liquid induced DNA gelation at remarkably low concentration. Colloids Surf A Physicochem Eng Asp 2018. [DOI: 10.1016/j.colsurfa.2017.10.083] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Abstract
DNA dissolved in ionic liquid (IL) solution (1-ethyl-3-methylimidazolium chloride, [C2mim][Cl]) showed a transition to the gel phase ([DNA] ≥ 1% (w/v)). The gelation time was 400 s for the 1% [IL] sample which reduced to 260 s for 5% [IL] concentration. Gelation times, obtained from the viscosity and ergodicity breaking from the dynamic structure factor data, were remarkably identical to each other. Correspondingly, the gelation temperature which was ∼60 °C increased to 67 °C with [IL] content. The small angle neutron scattering (SANS) structure factor profile revealed the presence of the following three distinct length scales: (a) mesh size, ξ ≈ 3 ± 0.5 nm for ionogels, and ≈0.73 ± 0.06 nm, for sol; (b) cross-sectional radius of DNA strand, Rc ≈ 1.6 ± 0.1 nm; and (c) the characteristic inter-cluster distance ≈33 ± 5 nm. Physical conformation of the DNA-IL complexes remained close to the Gaussian coil definition. It was observed that without IL, in the sol phase, the system was completely ergodic and did not gel, while on addition of IL a sudden transition to the non-ergodic (arrested) gel phase occurred. This was due to the formation of an amorphous network of DNA-IL complexes preceding gelation. In summary, it is shown that the DNA ionogels can be prepared with a tunable gel strength (27-70 Pa) and gelation temperature (60-67 °C). Further, the relaxation dynamics was found to be hierarchical in IL content of the gel, revealing considerable self-organization.
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Affiliation(s)
- Pankaj Kumar Pandey
- School of Physical Sciences, Jawaharlal Nehru University, New Delhi 110067, India
| | - Kamla Rawat
- Special Center for Nanosciences, Jawaharlal Nehru University, New Delhi 110067, India. and Inter University Accelerator Centre, New Delhi 110067, India
| | - V K Aswal
- State Physics Division, Bhabha Atomic Research Centre, Mumbai 400085, India
| | - J Kohlbrecher
- Laboratory for Neutron Scattering, Paul Scherrer Institut, Villigen, Switzerland
| | - H B Bohidar
- School of Physical Sciences, Jawaharlal Nehru University, New Delhi 110067, India and Special Center for Nanosciences, Jawaharlal Nehru University, New Delhi 110067, India.
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Priyadarshini E, Rawat K, Prasad T, Bohidar HB. Antifungal efficacy of Au@ carbon dots nanoconjugates against opportunistic fungal pathogen, Candida albicans. Colloids Surf B Biointerfaces 2018; 163:355-361. [PMID: 29335197 DOI: 10.1016/j.colsurfb.2018.01.006] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2017] [Revised: 01/04/2018] [Accepted: 01/06/2018] [Indexed: 11/30/2022]
Abstract
In the current study, we have investigated the toxicological effect of a novel hydrophilic nanoconjugate gold@carbon dot (Au@CD) and carbon dots (CDs) on the opportunistic fungal pathogen, Candida albicans. A homogenous experimental analysis was conducted for determining the toxicity of Au@CDs nanoconjugates of five different sizes ranging from 22 ± 2 to 35 ± 3 nm prepared using the carbon dots of mean hydrodynamic radius 12 ± 1 nm. The smallest size of nanoconjugate was synthesized using 0.3 mg ml-1 HAuCl4 precursor. Our study for the first time, conclusively establishes the size-dependent toxicity effect of these characterized nanoconjugates against the abovementioned fungal pathogen. The MIC80 value of smaller sized Au@CDs nanoconjugates, S1-S3 samples were 250, 500 and 500 μg ml-1, respectively, while nanoconjugates of Rh diameter greater than 30 nm (S4 and S5 samples) did not show any toxicity. The results thus demonstrate that alteration in composition (carbon vs Au@CDs) exhibits a profound effect on the susceptibility of Candida albicans cells. While a size-dependent toxicity was observed for the nanoconjugates, CDs were found to be quite toxic owing to their small size which facilitated their entry into the cells and challenged the biocompatibility of carbon allotropes.
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Affiliation(s)
| | - Kamla Rawat
- Special Centre for Nano Sciences, Jawaharlal Nehru University, New Delhi, India; Inter University Accelerator Centre, New Delhi, India.
| | - Tulika Prasad
- Special Centre for Nano Sciences, Jawaharlal Nehru University, New Delhi, India; Advanced Instrument Research Facility, Jawaharlal Nehru University, New Delhi, India
| | - H B Bohidar
- School of Physical Sciences, Jawaharlal Nehru University, New Delhi, India; Special Centre for Nano Sciences, Jawaharlal Nehru University, New Delhi, India.
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Pathak J, Priyadarshini E, Rawat K, Bohidar H. Complex coacervation in charge complementary biopolymers: Electrostatic versus surface patch binding. Adv Colloid Interface Sci 2017; 250:40-53. [PMID: 29128042 DOI: 10.1016/j.cis.2017.10.006] [Citation(s) in RCA: 48] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2017] [Revised: 10/10/2017] [Accepted: 10/29/2017] [Indexed: 10/18/2022]
Abstract
In this review, a number of systems are described to demonstrate the effect of polyelectrolyte chain stiffness (persistence length) on the coacervation phenomena, after we briefly review the field. We consider two specific types of complexation/coacervation: in the first type, DNA is used as a fixed substrate binding to flexible polyions such as gelatin A, bovine serum albumin and chitosan (large persistence length polyelectrolyte binding to low persistence length biopolymer), and in the second case, different substrates such as gelatin A, bovine serum albumin, and chitosan were made to bind to a polyion gelatin B (low persistence length substrate binding to comparable persistence length polyion). Polyelectrolyte chain flexibility was found to have remarkable effect on the polyelectrolyte-protein complex coacervation. The competitive interplay of electrostatic versus surface patch binding (SPB) leading to associative interaction followed by complex coacervation between these biopolymers is elucidated. We modelled the SPB interaction in terms of linear combination of attractive and repulsive Coulombic forces with respect to the solution ionic strength. The aforesaid interactions were established via a universal phase diagram, considering the persistence length of polyion as the sole independent variable.
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Pandey PK, Kaushik P, Rawat K, Aswal VK, Bohidar HB. Solvent hydrophobicity induced complex coacervation of dsDNA and in situ formed zein nanoparticles. Soft Matter 2017; 13:6784-6791. [PMID: 28819659 DOI: 10.1039/c7sm01222e] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Zein, a predominantly hydrophobic protein, was sustained as a stable dispersion in ethanol-water (80 : 20, % (v/v)) binary solvent at room temperature (25 °C). Addition of aqueous dsDNA solution (1% (w/v)) to the above dispersion prepared with the protein concentration of Czein = 0.01-0.5% (w/v) caused a concomitant change in ethanol content from 14-35% (v/v), which in turn generated zein nanoparticles in situ of size 80-120 nm increasing with water content. The subsequent associative interaction between DNA (polyanion; 2000 bps) and the positively charged zein nanoparticles, (at pH = 4) was driven by Coulombic forces, and by the solvent hydrophobicity due to the ethanol content of the binary solvent. Experimentally, two interesting regions of interaction were observed from turbidity, zeta potential, particle sizing, and viscosity data: (i) for Czein < 0.2% (w/v), zein nanoparticles of size 80 nm bind to dsDNA (primary complex) causing its condensation (apparent hydrodynamic size decreased from ≈2100 to 560 nm), and (ii) for 0.2% < Czein < 0.5% (w/v) larger nanoparticles (>80 nm) were selectively bound to primary complexes to form partially charge neutralized interpolymer soluble complexes (secondary complexes), followed by complex coacervation. During this process, there was depletion of water in the vicinity of the nucleic acid, which was replaced by hydration provided by the ethanol-water binary solvent. Equilibrium coacervate samples were probed for their microstructure by small angle neutron scattering, and for their viscoelastic properties by rheology. The interplay of solvent hydrophobicity, electrostatic interaction, and zein nanoparticle size dependent charge neutralization had a commensurate effect on this hitherto unexplored coacervation phenomenon.
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Affiliation(s)
- Pankaj Kumar Pandey
- School of Physical Sciences, Jawaharlal Nehru University, New Delhi 110067, India.
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Abstract
In this report, we present a novel application of gold-carbon dot nanoconjugates (Au@CDs) of an average size of around 12.6 nm as a sensor for the detection of cholesterol. The Au particles perform the dual function of displaying colorimetric sensing, and fluorescence quenching in response to cholesterol in the concentration range of 10-100 ppm (0.208-2.08 mM), wherein the carbon dots act as the fluorescent entity. Interestingly, the nanoconjugates were observed to show a high specificity to cholesterol resulting in their precipitation. A visible change in colour of the assay mixture along with fluorescence quenching was seen in the reaction mixture on treatment with cholesterol. The synthesized nanoconjugates had high selectivity towards cholesterol, even in the presence of interfering analytes, and a minimum detection limit of 0.12 ppm (0.0025 mM) in the linear range of 50-300 ppm (1-6.25 mM). We anticipate that these Au@CDs can be employed for the fabrication of enzyme-free strip-based biosensors for the detection of cholesterol.
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Ranjan R, Das P, Rawat K, Aswal VK, Kohlbrecher J, Bohidar HB. Self-assembly and gelation of TX-100 in water. Colloid Polym Sci 2017. [DOI: 10.1007/s00396-017-4078-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Sarkar T, Tiwari S, Rawat K, Solanki PR, Bohidar H. Hydrophilic, fluorescent and superparamagnetic iron oxide-carbon composite nanoparticles. Colloids Surf A Physicochem Eng Asp 2017. [DOI: 10.1016/j.colsurfa.2016.11.061] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Abstract
Herein, we report on folic acid (FA, a low molecular weight gelator) thermoreversible supramolecular organo (in 1 : 1 (v/v) water–DMSO binary solvent), and ionogels reported in 1-ethyl-3-methyl imidazolium chloride, [C2mim][Cl], and 1-octyl-3-methyl imidazolium chloride, [C8mim][Cl], solutions with 0.1 ≤ [IL] ≤ 5% (w/v).
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Affiliation(s)
- Rahul Ranjan
- School of Physical Sciences
- Jawaharlal Nehru University
- New Delhi 110067
- India
| | - Kamla Rawat
- Special Center for Nanosciences
- Jawaharlal Nehru University
- New Delhi 110067
- India
- Inter University Accelerator Centre
| | - H. B. Bohidar
- School of Physical Sciences
- Jawaharlal Nehru University
- New Delhi 110067
- India
- Special Center for Nanosciences
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Sharma A, Rawat K, Solanki PR, Bohidar HB. Surface patch binding-induced exfoliation of nanoclays and enhancement of physical properties of gelatin organogels. POLYM INT 2016. [DOI: 10.1002/pi.5281] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Affiliation(s)
- Anshu Sharma
- School of Physical Sciences; Jawaharlal Nehru University; New Delhi India
- Special Centre for Nanosciences; Jawaharlal Nehru University; New Delhi India
| | - Kamla Rawat
- Special Centre for Nanosciences; Jawaharlal Nehru University; New Delhi India
- Inter University Accelerator Centre; New Delhi 110067 India
| | - Pratima R Solanki
- Special Centre for Nanosciences; Jawaharlal Nehru University; New Delhi India
| | - Himadri B Bohidar
- School of Physical Sciences; Jawaharlal Nehru University; New Delhi India
- Special Centre for Nanosciences; Jawaharlal Nehru University; New Delhi India
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Das K, Sanwlani S, Rawat K, Haughn CR, Doty MF, Bohidar H. Spectroscopic profile of surfactant functionalized CdSe quantum dots and their interaction with globular plasma protein BSA. Colloids Surf A Physicochem Eng Asp 2016. [DOI: 10.1016/j.colsurfa.2016.07.023] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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29
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Mir IA, Rawat K, Bohidar HB. CuInGaSe nanocrystals for detection of trace amount of water in D2O (at ppm level). Crystal Research and Technology 2016. [DOI: 10.1002/crat.201600054] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Affiliation(s)
- Irshad Ahmad Mir
- School of Physical Sciences; Jawaharlal Nehru University; New Delhi 110067 India
| | - Kamla Rawat
- Special Center for Nanosciences; Jawaharlal Nehru University; New Delhi 110067 India
- Inter University Accelerator Centre (IUAC); New Delhi 110067 India
| | - H. B. Bohidar
- School of Physical Sciences; Jawaharlal Nehru University; New Delhi 110067 India
- Special Center for Nanosciences; Jawaharlal Nehru University; New Delhi 110067 India
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Pathak J, Rawat K, Aswal VK, Bohidar HB. Hierarchical Internal Structures in Gelatin-Bovine Serum Albumin/β-Lactoglobulin Gels and Coacervates. J Phys Chem B 2016; 120:9506-12. [PMID: 27526229 DOI: 10.1021/acs.jpcb.6b05378] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Herein, we report the comparative study of gels and complex coacervates of bovine serum albumin (BSA) and beta-lactoglobulin (β-Lg) with gelatin close to their common pI. Surface patch binding produced a range of new soft matter phases (interpolymer complexes) such as opaque coacervates (charge neutralized complexes) and transparent gels (overcharged complexes). We emphasize on the comparative study of the microstructure of coacervates and gels formed at different mixing ratios using small angle scattering (SANS) data. It was found that phase states were entirely defined by the mixing ratio r = [GB]:[β-Lg or BSA]. Thermo-viscoelastic profiles of aforesaid samples revealed a smaller storage modulus and lower melting temperature for coacervates compared to gels. Thermally activated samples generated additional phases that were also probed by SANS and rheology. Thus, it is established that intermolecular association between globular proteins and a random coil polypeptide can generate various soft matter states that may facilitate harvesting of novel biomaterials.
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Affiliation(s)
- Jyotsana Pathak
- School of Physical Sciences, Jawaharlal Nehru University , New Delhi 110067, India
| | - Kamla Rawat
- Special Center for Nanosciences, Jawaharlal Nehru University , New Delhi 110067, India.,Inter University Accelerator Centre , New Delhi 110067, India
| | - V K Aswal
- Solid State Physics Division, Bhabha Atomic Research Centre , Mumbai 400 085, India
| | - H B Bohidar
- School of Physical Sciences, Jawaharlal Nehru University , New Delhi 110067, India.,Special Center for Nanosciences, Jawaharlal Nehru University , New Delhi 110067, India
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Joshi N, Rawat K, Aswal V, Bohidar H. Smoluchowski aggregation kinetics, gelation, ergodicity breaking and aging dynamics of (1:1) Laponite-Montmorillonite mixed clay dispersions. Colloids Surf A Physicochem Eng Asp 2016. [DOI: 10.1016/j.colsurfa.2016.04.045] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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Affiliation(s)
- Nidhi Joshi
- Polymer
and Biophysics Laboratory, School of Physical Sciences, Jawaharlal Nehru University, New Delhi 110067, India
| | - Kamla Rawat
- Special
Center for Nanosciences, Jawaharlal Nehru University, New Delhi 110067, India
- Inter University Accelerator Centre (IUAC), New Delhi 110067, India
| | - H. B. Bohidar
- Polymer
and Biophysics Laboratory, School of Physical Sciences, Jawaharlal Nehru University, New Delhi 110067, India
- Special
Center for Nanosciences, Jawaharlal Nehru University, New Delhi 110067, India
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Mir IA, Das K, Rawat K, Bohidar H. Hot injection versus room temperature synthesis of CdSe quantum dots: A differential spectroscopic and bioanalyte sensing efficacy evaluation. Colloids Surf A Physicochem Eng Asp 2016. [DOI: 10.1016/j.colsurfa.2016.01.002] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
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Joshi N, Rawat K, Bohidar HB. Characterization of microstructure, viscoelasticity, heterogeneity and ergodicity in pectin-laponite-CTAB-calcium nanocomposite hydrogels. Carbohydr Polym 2016; 136:242-9. [PMID: 26572352 DOI: 10.1016/j.carbpol.2015.09.031] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2015] [Revised: 09/08/2015] [Accepted: 09/09/2015] [Indexed: 10/23/2022]
Abstract
In order to customize the viscoelastic properties of pectin gels, it is necessary to work on a composite platform. Herein, the gelation kinetics, and viscoelastic characterization of anionic polysaccharide pectin dispersion prepared in presence of nanoclay laponite are reported using dynamic light scattering and rheology measurements. The ratio Rg/Rh (Rg and Rh are radius of gyration and hydrodynamic radius respectively) determined from light scattering data revealed the presence of random coils of pectin chains inside the gel matrix. When nanoclay laponite was added to the pectin chains solution, two-phase separation was noticed instantaneously. Therefore, the surfactant cetyltrimethylammonium bromide [CTAB] was added to exfoliate the clay platelets in the dispersion, and also in its gel phase. The exfoliating agent cetyltrimethylammonium bromide ([CTAB]≈ cmc/10) helped to enhance the homogeneity and stability of the pectin-clay sols and gels. The storage and loss moduli (G' and G") of the composite gel changed significantly as function of nanoclay laponite content for concentration up to 0.03% (w/v) causing the softening of the gels (gel strength reduced by close to 50%) compared to pectin-calcium gel. However, as the concentration of nanoclay laponite was maintained between 0.01% and 0.03% (w/v), the gel rigidity (G') recovered by 30% (35-45 Pa). The transition from ergodic to non-ergodic state occurred during sol-gel transition owing to the presence of the nanoclay laponite. The gelation time was not too different from the ergodicity breaking time. Thus, the presence of nanoclay laponite in such minute concentration is shown to cause considerable change in the thermo-physical property of the composite gels. This material property modulation will facilitate designing of soft gels having storage modulus continuously varying in the wide range of 10-70 Pa while keeping the gelation temperature mostly unaltered.
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Affiliation(s)
- Nidhi Joshi
- Polymer and Biophysics Laboratory, School of Physical Sciences, Jawaharlal Nehru University, New Delhi 110067, India
| | - Kamla Rawat
- Special Center for Nanosciences, Jawaharlal Nehru University, New Delhi 110067, India; Inter University Accelerator Centre (IUAC), New Delhi 110067, India.
| | - H B Bohidar
- Polymer and Biophysics Laboratory, School of Physical Sciences, Jawaharlal Nehru University, New Delhi 110067, India; Special Center for Nanosciences, Jawaharlal Nehru University, New Delhi 110067, India.
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35
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Abstract
Self assembly of surfactant free liposome-like nanoparticle.
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Affiliation(s)
- Nisha Pawar
- Department of Physics
- Indian Institute of Technology
- Kharagpur
- India
- School of Physical Sciences
| | - Kamla Rawat
- Special Centre for Nanosciences
- Jawaharlal Nehru University
- New Delhi-110067
- India
- Inter University Accelerator Centre (IUAC)
| | - H. B. Bohidar
- School of Physical Sciences
- Jawaharlal Nehru University
- New Delhi-110067
- India
- Special Centre for Nanosciences
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Joshi N, Sharma A, Asokan K, Rawat K, Kanjilal D. Effect of hydrogen ion implantation on cholesterol sensing using enzyme-free LAPONITE®-montmorillonite electrodes. RSC Adv 2016. [DOI: 10.1039/c5ra27523g] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Electrochemical profiling of LAPONITE®-montmorillonite/indium tin oxide (L-MMT/ITO) electrodes irradiated with 20 keV H2+ ion beam with variable fluence ranging from 1012 to 1016 ions per cm2.
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Affiliation(s)
- Nidhi Joshi
- School of Physical Sciences
- Jawaharlal Nehru University
- New Delhi 110067
- India
| | - Abhimanyu Sharma
- Special Center for Nanosciences
- Jawaharlal Nehru University
- New Delhi 110067
- India
- Inter University Accelerator Centre (IUAC)
| | - K. Asokan
- Inter University Accelerator Centre (IUAC)
- New Delhi 110067
- India
| | - Kamla Rawat
- Special Center for Nanosciences
- Jawaharlal Nehru University
- New Delhi 110067
- India
- Inter University Accelerator Centre (IUAC)
| | - D. Kanjilal
- Inter University Accelerator Centre (IUAC)
- New Delhi 110067
- India
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Abstract
Size-dependent (2.5 and 6.3 nm) interaction of MPA modified hydrophilic CdSe quantum dots with lysozyme are reported.
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Affiliation(s)
- Kishan Das
- School of Physical Sciences
- Jawaharlal Nehru University
- New Delhi 110067
- India
| | - Kamla Rawat
- Special Center for Nanosciences
- Jawaharlal Nehru University
- New Delhi 110067
- India
- Inter University Accelerator Centre (IUAC)
| | - Rajan Patel
- Centre for Interdisciplinary Research in Basic Sciences
- Jamia Millia Islamia
- New Delhi-110025
- India
| | - H. B. Bohidar
- School of Physical Sciences
- Jawaharlal Nehru University
- New Delhi 110067
- India
- Special Center for Nanosciences
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Pathak J, Rawat K, Bohidar HB. Thermo-reversibility, ergodicity and surface charge–temperature dependent phase diagram of anionic, cationic and neutral co-gels of gelatin–BSA complexes. RSC Adv 2016. [DOI: 10.1039/c6ra03830a] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
We have investigated the gelation behavior of polyampholyte gelatin B (GB) in the presence of colloidal plasma protein bovine serum albumin (BSA) as a function of mixing ratio (r = GB : BSA = 1.5–4), entire pH range, and temperature (20–45 °C).
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Affiliation(s)
- Jyotsana Pathak
- School of Physical Sciences
- Jawaharlal Nehru University
- New Delhi 110067
- India
| | - Kamla Rawat
- Special Center for Nanosciences
- Jawaharlal Nehru University
- New Delhi 110067
- India
- Inter University Accelerator Centre (IUAC)
| | - H. B. Bohidar
- School of Physical Sciences
- Jawaharlal Nehru University
- New Delhi 110067
- India
- Special Center for Nanosciences
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Joshi N, Sharma A, Rawat K, Asokan K, Solanki PR, Lakshmi GBVS, Kanjilal D, Bohidar HB. Comparative evaluation of enzyme-free nanoclay-ionic liquid based electrodes for detection of bioanalytes. RSC Adv 2016. [DOI: 10.1039/c6ra11514d] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Enzyme-free electrodes were fabricated using mixed nanoclays and ionic liquids.
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Affiliation(s)
- Nidhi Joshi
- Polymer and Biophysics Laboratory
- School of Physical Sciences
- Jawaharlal Nehru University
- New Delhi 110067
- India
| | - Abhimanyu Sharma
- Special Center for Nanosciences
- Jawaharlal Nehru University
- New Delhi 110067
- India
- Inter University Accelerator Centre
| | - Kamla Rawat
- Special Center for Nanosciences
- Jawaharlal Nehru University
- New Delhi 110067
- India
- Inter University Accelerator Centre
| | - K. Asokan
- Inter University Accelerator Centre
- New Delhi 110067
- India
| | - P. R. Solanki
- Special Center for Nanosciences
- Jawaharlal Nehru University
- New Delhi 110067
- India
| | | | - D. Kanjilal
- Inter University Accelerator Centre
- New Delhi 110067
- India
| | - H. B. Bohidar
- Polymer and Biophysics Laboratory
- School of Physical Sciences
- Jawaharlal Nehru University
- New Delhi 110067
- India
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Abstract
Morphology dependent interaction of model anisotropic nanoparticles with globular plasma proteins.
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Affiliation(s)
- Kishan Das
- School of Physical Sciences
- Jawaharlal Nehru University
- New Delhi 110067
- India
| | - Kamla Rawat
- Special Center for Nanosciences
- Jawaharlal Nehru University
- New Delhi 110067
- India
- Inter University Accelerator Centre (IUAC)
| | - H. B. Bohidar
- School of Physical Sciences
- Jawaharlal Nehru University
- New Delhi 110067
- India
- Special Center for Nanosciences
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Abstract
We report the studies relating to fabrication of an efficient immunosensor for Vibrio cholerae detection. Magnetite (iron oxide (Fe(3)O(4))) nanoparticles (NPs) have been synthesized by the co-precipitation method and capped by citric acid (CA). These NPs were electrophoretically deposited onto indium-tin-oxide (ITO)-coated glass substrate and used for immobilization of monoclonal antibodies against Vibrio cholerae (Ab) and bovine serum albumin (BSA) for Vibrio cholerae detection using an electrochemical technique. The structural and morphological studies of Fe(3)O(4) and CA-Fe(3)O(4)/ITO 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 Fe(3)O(4), CA-Fe(3)O(4) nanoparticles obtained were about 29 ± 1 nm and 37 ± 1 nm, respectively. The hydrodynamic radius of the nanoparticles was found to be 77.35 nm (Fe(3)O(4)) and 189.51 nm (CA-Fe(3)O(4)) by DLS measurement. The results of electrochemical response studies of the fabricated BSA/Ab/CA-Fe(2)O(3)/ITO immunosensor exhibits a good detection range of 12.5-500 ng mL(-1) with a low detection limit of 0.32 ng mL(-1), sensitivity 0.03 Ω/ng ml(-1) cm(-2), and reproducibility more than 11 times.
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Affiliation(s)
- Anshu Sharma
- Special Centre for Nanosciences, Jawaharlal Nehru University, New Delhi-110067, India. School of Physical Science, Jawaharlal Nehru University, New Delhi-110067, India
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Sharma A, Rawat K, Solanki P, Bohidar H. Gelatin-Ionic liquid Based Platform for Glucose Detection. Curr Top Med Chem 2015; 15:1257-67. [DOI: 10.2174/1568026615666150330112429] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2014] [Revised: 02/01/2015] [Accepted: 02/20/2015] [Indexed: 11/22/2022]
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Pathak J, Rawat K, Sanwlani S, Bohidar HB. Interaction of Globular Plasma Proteins with Water-Soluble CdSe Quantum Dots. Chemphyschem 2015; 16:1777-86. [DOI: 10.1002/cphc.201402629] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2014] [Revised: 01/23/2014] [Indexed: 12/19/2022]
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Abstract
Representative model of protein–protein separation in a BSA–GB–β-Lg aqueous solution.
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Affiliation(s)
- Jyotsana Pathak
- Polymer and Biophysics Laboratory
- School of Physical Sciences
- Jawaharlal Nehru University
- New Delhi 110067
- India
| | - Kamla Rawat
- Special Center for Nanosciences
- Jawaharlal Nehru University
- New Delhi 110067
- India
- Inter University Accelerator Centre (IUAC)
| | - V. K. Aswal
- Solid State Physics Division
- Bhabha Atomic Research Centre
- Mumbai-400085
- India
| | - H. B. Bohidar
- Polymer and Biophysics Laboratory
- School of Physical Sciences
- Jawaharlal Nehru University
- New Delhi 110067
- India
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Asthana D, Shukla J, Dana S, Rani V, Ajayakumar MR, Rawat K, Mandal K, Yadav P, Ghosh S, Mukhopadhyay P. Assorted morphosynthesis: access to multi-faceted nano-architectures from a super-responsive dual π-functional amphiphilic construct. Chem Commun (Camb) 2015; 51:15237-40. [DOI: 10.1039/c5cc05198c] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
An electronically segmented amphiphile was created by conjugating two π-functional units (HQ/NDI) for the first time.
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Pathak J, Rawat K, Bohidar HB. Charge heterogeneity induced binding and phase stability in β-lacto-globulin–gelatin B gels and coacervates at their common pI. RSC Adv 2015. [DOI: 10.1039/c5ra07195j] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
Abstract
An understanding of the interactions between gelatin B (GB) and β-lacto-globulin (β-Lg) mainly arising from surface selective patch binding occurring at their common pI (≈5.0 ± 0.5) in the absence of added salt.
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Affiliation(s)
- Jyotsana Pathak
- Polymer and Biophysics Laboratory
- School of Physical Sciences
- Jawaharlal Nehru University
- New Delhi 110067
- India
| | - Kamla Rawat
- Special Center for Nanosciences
- Jawaharlal Nehru University
- New Delhi 110067
- India
- Inter University Accelerator Centre (IUAC)
| | - H. B. Bohidar
- Polymer and Biophysics Laboratory
- School of Physical Sciences
- Jawaharlal Nehru University
- New Delhi 110067
- India
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Pathak J, Rawat K, Aswal VK, Bohidar HB. Hierarchical surface charge dependent phase states of gelatin-bovine serum albumin dispersions close to their common pI. J Phys Chem B 2014; 118:11161-71. [PMID: 25171436 DOI: 10.1021/jp5068846] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
We report interaction between bovine serum albumin ([BSA] = 1% (w/v)) and gelatin B ([GB] = 0.25-3.5% (w/v)) occurring close to their common isoelectric pH (pI). This interaction generated distinguishable multiple soft matter phases like opaque coacervates (phase I) and transparent gels (phase II), where the former are composed of partially charge neutralized intermolecular complexes (zeta potential, ζ ≤ 0) and the latter of overcharged complexes (ζ ≥ 0) that organized into a network pervading the entire sample volume. These phase states were completely governed by the protein mixing ratio r = [GB]:[BSA]. Coacervates, when heated above 32 °C, produced thermoirreversible turbid gels (phase III), stable in the region 32 ≥ T ≤ 50 °C. When the transparent gels were heated to T ≥ 34 °C, these turned into turbid solutions that did form a turbid fragile gel (phase IV) upon cooling. Mechanical and thermal behaviors of aforesaid coacervates (phase I) and gels (phase II) were examined; coacervates had lower storage modulus and melting temperature compared to gels. Cole-Cole plots attributed considerable heterogeneity to coacervate phase, but gels were relatively homogeneous. Raman spectroscopy data suggested differential microenvironment for these phases. Coacervates were mostly hydrated by partially structured water with degree of hydration dependent on gelatin concentration whereas for gels hydration was invariant of [GB]. Small-angle neutron scattering (SANS) data gave static structure factor profiles, I(q), versus wavevector q, that were remarkably different. For transparent gels, data could be split into two distinct regions: (i) 0.01 < q < 0.1 Å(-1), I(q) = IOZ(0)/(1 + q(2)ζgel(2))(2) (Debye-Bueche function) with ζgel = 9-13 nm, and (ii) 0.1 < q < 0.35 Å(-1), I(q) = IOZ(0)/(1 + q(2)ξgel(2)) (Ornstein-Zernike function) with ξgel = 3.1 ± 0.6 nm. Similarly, for coacervate, the aforesaid two q-regions were described by (i) I(q) = IPL(0)q(-α) with α = 1.7 ± 0.1 and (ii) I(q) = IOZ(0)/(1 + q(2)ξcoac(2)) with ξcoac = 1.6 ± 0.2 nm, a value close to the persistence length of gelatin chain (lp ≈ 2 nm). Phase transition from one equilibrium state to another, i.e., phase I to II, was hierarchical in the charge state of the protein-protein complex. Within the same charge state, transition from phase I to III and from phase II to IV was thermally activated. The aforesaid mechanisms are captured in a unique ζ-T phase diagram.
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Affiliation(s)
- Jyotsana Pathak
- Polymer and Biophysics Laboratory, School of Physical Sciences, and ‡Special Center for Nanosciences, Jawaharlal Nehru University , New Delhi 110067, India
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