Browsing by Author "Shere Afgan"

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A non-covalently cross-linked self-healing hydrogel for drug delivery: characterization, mechanical strength, and anti-cancer potential
(Royal Society of Chemistry, 2024) Sheetal Jaiswal; Sandeep Kumar; Paramjeet Yadav; Krishtan Pal; Shere Afgan; Arvind Acharya; Ravi Prakash; Pralay Maiti; Rajesh Kumar
This research article introduced a novel one-pot method for synthesizing hydrogels, utilizing iron ions (Fe3+) and guar gum succinate (GGS) as cross-linkers. These hydrogels were characterized as cross-linked networks, with hydrogen bonds forming a sacrificial network and coordination bonds serving as the primary network. The reversible nature of these networks was attributed to the hydrogels’ exceptional toughness and remarkable self-healing properties. The hydrogel's chemical structure was confirmed through FTIR spectroscopy. XRD analysis highlighted the disruption of the crystalline nature of GGS upon cross-linking with Fe3+. By controlling the Fe3+ concentration, the hydrogels’ mechanical properties were tailored. Rheological measurements demonstrated mechanical and self-healing properties, while swelling studies revealed pH-dependent behavior. In vitro studies showed the hydrogels’ significant anti-proliferative effect against U-87MG (human glioblastoma) cancer cells, while remaining biocompatible with normal cell lines (HEK-293). These results indicated the potential application of these hydrogels in advancing cancer treatment strategies. © 2024 The Royal Society of Chemistry.
Allylthiourea-mediated self-healing hydrogels based on poly(vinyl alcohol): Enhanced cell viability/biocompatibility and sustained drug release
(John Wiley and Sons Inc, 2024) Paramjeet Yadav; Shere Afgan; Krishtan Pal; Sheetal Jaiswal; Pooja Goswami; Ravi Prakash; Rajesh Kumar; Biplob Koch; Pralay Maiti
Hydrogel-based materials represent promising candidates for drug delivery. In our research, we synthesized a series of hydrogels—PVATU-1 (2:1), PVATU-2 (1:1), and PVATU-3 (0.5:1)—by adjusting the poly(vinyl alcohol) (PVA) ratio while maintaining a constant ratio of allylthiourea (ATU) monomer and glutaraldehyde cross-linker, aiming to understand their impacts on gelation. These PVATU hydrogels displayed impressive swelling in neutral conditions and exhibited visible self-healing capabilities. Notably, PVATU-1 shows superior mechanical strength among the variants. Surface analysis using AFM and SEM unveiled porous structures within the hydrogels, while thermal stability tests indicated their resilience up to 200°C. DSC analysis revealed minimal variation in glass transition temperatures (Tg), affirming stability. A distinct endothermic peak around 250–350°C across all hydrogels confirmed their semi-crystalline nature, corroborated by powder XRD. Noteworthy, PVATU-1 demonstrated optimal loading and releasing efficiency for levofloxacin, with 74.5% loading and 82.8% releasing efficiency within 18 h. Biocompatibility assessments on HeLa cells affirmed the nontoxicity of PVATU hydrogel treatments. © 2024 Wiley Periodicals LLC.
Development of chitosan towards the self-healing and mechanically stronger biocompatible hydrogel
(Elsevier B.V., 2022) Shere Afgan; Paramjeet Yadav; Sheetal Jaiswal; Krishtan Pal; Rajesh Kumar; Virendra Singh; Biplob koch
Nontoxic, self-healing and biocompatible Chitosan grafted poly (maleic anhydride) based hydrogel (CSHG) have been developed by using Chitosan (CS) and maleic anhydride (MAH) having reasonable mechanical strength with biocompatibility. The self-healing arises due to the presence of free primary amine group and carboxyl group in grafted chitosan either dynamic imine covalent interaction or non-covalent (H-bonding) interactions. In addition to this, the hydrogel showed tremendous swelling at various pH values viz. - 2, 7 and 9, and morphological study reveals the porous nature of the synthesized CSHG hydrogel. The cell viability (MTT) of CS and CSHG was performed on MCF-7 (breast cancer cell line), and phase contrast (cell imaging) of CS and CSHG was taken at 1:5, 1:10, 1:50 and 1:100 ratios in both cases which do not induce any significant changes in cellular morphology thus makes it biocompatible and can be used as biological applications. © 2022 Indian Chemical Society
Development of graft copolymer of carboxymethylcellulose and N-vinylcaprolactam towards strong antioxidant and antibacterial polymeric materials
(Elsevier B.V., 2018) Ashok Kumar; Deepak; Swati Sharma; Shere Afgan; Rajesh Kumar; Anand Kumar Keshari; Ragini Srivastava
The present paper reports graft copolymerization of N-vinylcaprolactam (NVCL) onto carboxymethylcellulose (CMC) using tert-butyl hydroperoxide (TBHP) initiator in N2 atmosphere. The grafting was found to be highest when concentrations of CMC, NVCL and TBHP were 6.25 × 10−2 g dm−3, 10 × 10−3 mol dm−3 and 20 × 10−5 mol dm−3 respectively. The graft copolymer (CMC-g-PNVCL-1) was characterized by FTIR, 1HNMR, SEM, AFM, XRD and TGA analysis. The antioxidant activity of the graft copolymer was found to be higher (3.81%) than CMC and slightly less (5.47%) than the standard one (butylated hydroxytoluene, BHT). The hydroxyl radical scavenging activity of graft copolymer was found to be slightly less (13.69%) than CMC and more (44.20%) than the BHT. The hydrogen peroxide scavenging activity of graft copolymer was observed to be less (20.42%) than CMC and 53.34% less than BHT. The superoxide scavenging activity of graft copolymer was greater than the both. Compared to CMC the graft copolymer has shown greater antibacterial activity against S. aureus, Proteus vulgaris and S. typhi bacteria and less against Klebsiella pneumonia and Salmonella typhimurium. © 2018 Elsevier B.V.
Generation of multicellular tumor spheroids via 3D cell culture utilizing a hydrogel comprising chitosan and allylthiourea
(Royal Society of Chemistry, 2023) Paramjeet Yadav; Shere Afgan; Virendra Singh; Krishtan Pal; Sheetal Jaiswal; Rajesh Kumar; Biplob Koch
Hydrogels made with chitosan (CS) biopolymer can undergo mechanical and chemical modifications that can lead to new properties and functions in the biomedical field, which can be used for 3D cell culture as well as the formation of tumor spheroids that mimic the microenvironment of a tissue or organ. Chitosan-poly(allylthiourea) (CSATU)-based hydrogels were synthesized, which exhibit self-healing properties, biocompatibility, nontoxicity, and reasonable mechanical strength. The ratio of chitosan was varied to synthesize a series of CSATU hydrogels viz. CSATU-1 containing (CS : ATU) in a (2 : 1) ratio, CSATU-2 containing (CS : ATU) in a (1 : 1) ratio, and CSATU-3 containing (CS : ATU) in a (1 : 2) ratio. The swelling of all CSATU hydrogels was found to be maximum in a neutral medium. The maximum mechanical strength was demonstrated by the CSATU-1 hydrogel among all hydrogels. The surface morphology of the hydrogels was analyzed using AFM and SEM, while the thermal stability was determined using TGA, revealing that the hydrogels were stable up to 200 °C, and the Tg values of CS and ATU were observed at approximately 97 °C and 74 °C, respectively. Although there is minimal variation among the Tg values of each hydrogel, a significant endothermic peak was observed at around 60-70 °C for all hydrogels, and the semi-crystalline nature was analyzed using powder XRD. However, the CSATU hydrogels were characterized using FT-IR spectroscopy. Furthermore, the CSATU hydrogels have been explored to investigate the biocompatibility of the cells. Our results revealed that the CSATU hydrogels were nontoxic to the T-cell lymphoma and MCF-7 cells. Additionally, all three hydrogels have successfully established the formation of multicellular tumor spheroids. Overall, our present study demonstrated that the synthesized CSATU hydrogels can be used as a promising platform for spheroid development, which has potential applications in tissue engineering and drug development. © 2023 The Royal Society of Chemistry.
L-Alanine induced thermally stable self-healing guar gum hydrogel as potential drug vehicle for sustained release of hydrophilic drug
(Elsevier Ltd, 2019) Swati Sharma; Shere Afgan; Deepak; Ashok Kumar; Rajesh Kumar
A simple approach for preparing self-healable guar gum-graft-acrylic acid (GG-PAA) hydrogel using L-alanine as a cross-linking agent was introduced for the first time. It drastically modifies the mechanical strength of the hydrogel to G′ = 90,570 Pa. Thus, a series of guar gum (GG) based hydrogel was synthesized by varying the concentration of L-alanine from 0.4 to 1% w/v. The hydrogel was characterized by different analytical techniques such as FTIR, HRSEM etc. The mechanical strength of the hydrogel was investigated by rheology analysis and it was observed in terms of storage and loss modulus i.e. G′ & G′′, respectively. Maximum G′ & G′′ (90,560 Pa & 60,820 Pa) were observed when 1 wt% of L-alanine was used as a cross-linking agent. This GG based hydrogel have shown excellent swelling i.e. up to 3350%, which indicates its porous network. The synthesized hydrogel has been identified as a controlled drug delivery gel, which releases 98% of the highly water-soluble loaded drug in 140 h. © 2019 Elsevier B.V.
Permselective Films of Sulfonic Acid-Functionalized N-Vinylcarbazole Block Copolymers: Optoelectronic Studies and Electrochemical Sensing of Dopamine
(American Chemical Society, 2025) Shiwani R. Singh; Smita Singh; Shere Afgan; Paramjeet Yadav; Vellaichamy Ganesan; Rajesh C.Arun Kumar
This study focused on incorporating block copolymers of poly(N-vinylcarbazole) [PNVCz] with three distinct sulfonic acid polymer derivatives. The synthesis of the polymers involved utilizing the xanthate reversible addition-fragmentation chain transfer (RAFT) polymerization technique. Nanomicelle block copolymers, including poly(N-vinylcarbazole)-b-poly(2-methyl-2-propene-1-sulfonic acid) [PNVCz-b-PMPSA], poly(N-vinylcarbazole)-b-poly(2-acrylamido-2-methyl-1-propanesulfonic acid) [PNVCz-b-PAMPS], and poly(N-vinylcarbazole)-b-poly(styrenesulfonic acid) [PNVCz-b-PSSA], were synthesized using a xanthate RAFT agent, (2-ethyl isobutyrate)-(O-ethyl xanthate) [EIX]. The linear relationship between molar mass and conversion suggests pseudo-first-order kinetics. The molar mass distribution of the copolymers ranged from 1.17 to 1.30. Characterization of the block copolymers and homopolymers included techniques such as 1H NMR, X-ray diffraction [XRD], Fourier transform infrared spectroscopy [FTIR], scanning electron microscopy (SEM), gel permeation chromatography (GPC), thermogravimetric analysis (TGA), and differential scanning calorimetry (DSC). The block copolymer’s aqueous solution at a concentration of 1 mg/mL demonstrated self-assembly within the 50-150 nm range, as evidenced by dynamic light scattering [DLS] and transmission electron microscopy [TEM]. The permselective properties exhibited by the polymer films were advantageously utilized for the electrochemical sensing of dopamine in the presence of ascorbic acid. The optical characteristics of the block copolymers were also assessed using UV-vis absorption and photoluminescence techniques. These block copolymers display captivating self-organization tendencies and exhibit ion-exchange properties facilitating the detection of dopamine. © 2025 American Chemical Society.
Polysaccharide-based Self-healing hydrogels and their diverse Applications
(Association of Carbohydrate Chemists and Technologists, 2021) Shere Afgan; Paramjeet Yadav; Sheetal Jaiswal; Rajesh Kumar
Self-healing or shape-memory is one of the most ultimate characteristics of living tissues. ‘Self-healing hydrogels’ are three-dimensionally cross-linked polymeric materials that have played an important role in numerous fields because of their property to recover itself spontaneously after being damaged. In recent years, the researcher has particularly focused on self-healing hydrogels based on natural polysaccharides due to their promising properties such as biocompatibility, biodegradability, and their ability to self-repair. This self-repair property inspired in nature gives them the possibility of maintaining their integrity even after damage, owing to specific physical interactions or dynamic covalent bonds that provide reversible linkages. In this review, we have covered the different types of polysaccharides based on self-healing hydrogels and their formation mechanism is offered together with the potential applications in the various fields. © 2021. Trends In Carbohydrate Research. All Rights Reserved.
PVA/AMPS hydrogels: Promising adsorbents for wastewater treatment with high efficiency and reusability
(John Wiley and Sons Inc, 2025) Paramjeet Yadav; Shere Afgan; Shiwani R. Singh; Ravi Prakash; Pralay Maity; Rajesh Rakesh Kumar
A PVAMPS hydrogel was synthesized through chemical cross-linking and semi-interpenetration of Poly (vinyl Alcohol) (PVA) and 2-Acrylamido-2-methyl-1-propanesulfonic acid (AMPS) with glutaraldehyde in distilled water. Various ratios of PVA/AMPS, namely PVAMPS-1 (2:1), PVAMPS-2 (1:1), and PVAMPS-3 (1:2), were examined to understand their individual impacts on gel formation. The synthesis of hydrogels was confirmed using FT-IR and solid-state 13C NMR spectroscopy. The PVAMPS hydrogels demonstrated high efficiency as a selective adsorbent for removing cationic dyes, such as Methylene Blue, Safranine-O, and Thionine, from aqueous solutions, with over 90% removal of cationic dyes observed within 18 hours. Regeneration and reusability studies revealed that even after four cycles, the adsorption capacity of the PVAMPS hydrogels remained exceptionally high, with removal rates exceeding 90% for Methylene Blue. However, for Safranine-O and Thionine, the removal rates dropped to 20% and 23%, respectively, after four cycles. These findings underscore the promising potential of PVAMPS hydrogels for the removal of cationic dyes in wastewater treatment. © 2024 Wiley Periodicals LLC.
Stimuli-Responsive Polymeric Hydrogel-Copper Nanocomposite Material for Biomedical Application and Its Alternative Application to Catalytic Field
(Wiley-Blackwell, 2017) Swati Sharma; Deepak; Ashok Kumar; Shere Afgan; Rajesh Kumar
Naturally occurring non-toxic, biocompatible chitosan based hydrogel nanocomposite with copper nanoparticle was synthesized via in-situ free radical polymerization using chitosan (CS) as substrate, acrylamide (Am) as monomer, copper nanoparticles (CuNPs), ammonium persulphate as an initiator and glutaraldehyde as a cross-linking agent. The synthesized CS-PAm-CuNPs hydrogel nanocomposite was characterized by rheology studies, HRSEM & FT-IR spectroscopy. It shows excellent swelling up to 300% in wide range of pH of 3–9 with good mechanical strength (exhibit 1380% stain value). Further, synthesized hydrogel nanocomposite was found to be a multi-responsive due biomedical application and alternative application to catalytic field. The synthesized hydrogel-nanocomposite showed 96% release of highly water soluble levofloxacin antibiotic drug in blood serum in controlled manner up to 30 h and its catalytic activity (90%). Successful reduction of 4-nitrophenol into 4-aminophenol in presence of hydrogel nanocomposite confirms its Catalytic property. This hydrogel nanocomposite catalyst was found to be ecofriendly and it can be reused after washing it with distilled water. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
Studies on non-gelatinous & thermo-responsive chitosan with the N-isopropylacrylamide by RAFT methodology for control release of levofloxacin
(Elsevier B.V., 2020) Deepak; Shere Afgan; Krishtan Pal; Rajesh Kumar
The non-gelatinous and thermo-responsive properties were introduced in chitosan by incorporating the chain of poly(N-isopropylacrylamide) via reversible addition-fragmentation chain transfer (RAFT) polymerization. To achieve this, the reaction was carried out at 80 °C by modifying the chitosan(CS) with RAFT agent as a macroinitiator (CS-RAFT), where the amine group of CS was protected with phthalic anhydride and then reacted with 4-cyano-4-[(dodecyl sulfanyl thiocarbonyl)sulfanyl]-pentanoic acid (CDSTSP) to form CS-RAFT agent. Further, the addition of NIPAAm chains onto CS-RAFT was carried out in N,N′-dimethylformamide (DMF) solvent by using 2,2′-azobisisobutyronitrile (AIBN) as an initiator in N2 atmosphere. The controlled addition of NIPAAm chains on to CS was confirmed by 1H NMR spectroscopy, further, a kinetic study was performed to get the characteristic features of the RAFT reaction. The product was characterized by 1H NMR, FT-IR, UV–Visible spectroscopy, XRD, SEM, and TGA analyses. The product in aqueous solution showed LCST at 2.0 mg/mL on 33 ± 0.1 °C. Further, beads were prepared with the sodium alginate and loaded the water-soluble levofloxacin drug (60% w/w loading was achieved). The drug delivery process was studied in-vitro at 37 ± 0.1 °C & pH 7.4, which shown controlled release of drug up to 32 h and it was 71% of the loaded levofloxacin. © 2020 Elsevier B.V.
Synthesis & characterization of amino acid-based acrylamide derived amphiphilic block copolymer using a new xanthate and its influence on cell cytotoxicity & cell viability
(Elsevier Ltd, 2023) Shere Afgan; Krishtan Pal; Arti Srivastava; Koushik Nandy; Paramjeet Yadav; Sheetal Jaiswal; Rajan Singh; Rakesh K. Singh; Rajesh Kumar
The development of amino acid-based polymers was due to their unique properties and structures like of biocompatible polymers having sensitive effects for numerous medicinal and biological actions like biochemical sensing and controlled release of drugs. To achieve this, poly (N-vinylpyrrolidone) (PNVP) and its block copolymer poly (N-vinylpyrrolidone)-b-poly (N-acryloyl-L-phenylalanine) (PNVP-b-PNALP) were synthesized by using a xanthate i.e., ethyl 2-((isopropoxycarbonothioyl)thio)-2-methylpropanoate (IPX), which exhibits good control RAFT polymerization. The plot between molar mass and conversion yields a linear line which confirms the pseudo-first-order kinetics, and molar mass distribution (Ðm) was found between (1.50–1.24). Both polymers were characterized by 1H NMR, FTIR, DSC, TGA-DTA, GPC, and XRD analysis. TEM and DLS study of the aqueous solution of the block copolymer (PNVP-b-PNALP) exhibited self-assembly (119–160 nm with a few smaller particles of 91 nm). Different concentrations of polymers (200–0.75 μM) were evaluated for their toxicities on macrophages (RAW 264.7) and cancer (MCF7) cell lines. The polymers were found to be nontoxic as we did not observe any significant changes in the rate of proliferation of both cells even at higher concentrations (up to 100 μM). However, the polymers were found to induce apoptosis-like changes in the cancer cells up to 100 μM, albeit not significant. © 2023 Elsevier Ltd
Synthesis & characterization of tri arm Indole based ATRP Polymer and antibacterial study with its silver nanocomposite
(Springer Science and Business Media B.V., 2022) Ambika Srivastava; Shere Afgan; Paramjeet Yadav; Rajesh Kumar; Arti Srivastava; Ravindra Nath Kharwar
Hyperbranched poly (tris (1-allyl-1H-indol-3-yl) methane -co- 2-propionyloxy ethyl acrylate [Poly (TAIM-co-PEA)] was prepared by self-condensing vinyl copolymerization (SCVCP) of tris (1-allyl-1H-indol-3-yl) methane (TAIM) with 2-(2-bromopropionyloxy) ethyl acrylate (BPEA) via ATRP using the equimolar amount of TAIM and BPEA. In this hyperbranched polymer matrix, silver nanoparticles [Poly (TAIM-co-PEA)]N were prepared using a reductive method. The resultant polymer [Poly (TAIM-co-PEA)] and its silver nanocomposite [Poly (TAIM-co-PEA)]N were characterized by FTIR, 1H NMR, GPC, UV-visible, and TEM. The synthesized polymer has a nanopore size distribution centred at approximately 1.76 nm. Thermal stability of hyperbranched polymer [Poly (TAIM-co-PEA)] and its silver nanocomposite [Poly (TAIM-co-PEA)]N was studied by TGA/DTA and DSC. Antibacterial activity of porous polymer [Poly (TAIM-co-PEA)] and its silver nanocomposite [Poly (TAIM-co-PEA)]N was active against E. fecalis, E. coli, and K. pneumonae bacteria. © 2022, The Polymer Society, Taipei.
The benzyl ethyl trithiocarbonate mediated control synthesis of a block copolymer containing N-vinyl pyrrolidone by RAFT methodology: Influence of polymer composition on cell cytotoxicity and cell viability
(Elsevier Ltd, 2020) Koushik Nandy; Arti Srivastava; Shere Afgan; Deepak; Rajesh Kumar; Arun Kumar Rawat; Rajan Singh; Rakesh K. Singh
Benzyl ethyl trithiocarbonate (BET) mediated reversible addition–fragmentation chain transfer (RAFT) polymerization was carried out in dry 1,4-dioxane medium at 85 °C to synthesize Poly(n-Butyl Acrylate) (PBA) with pre-determined molecular weight (Mn 7999), narrow polydispersity (PDI 1.13) and precise chain end structure. The end chain functionality of macro chain transfer agent (CTA) was proved by homo-chain and hetero-chain extension polymerization experiment to get the poly (n-Butyl Acrylate) (Mn 17902) and poly (n-Butyl Acrylate)-b-poly(N-Vinyl Pyrrolidone) di-block copolymer (Mn 16029) respectively. Resulting polymers were characterized by 1H NMR, FTIR, GPC, TGA-DTA, DTG, DSC. The kinetic investigations confirmed the pseudo-first-order kinetic of the homopolymerization and linear evolution of the molar mass w.r.t. conversion within the range of polydispersity (PDI) (1.11 –1.20) in dry 1, 4-dioxane medium. The cyto-toxicities of PBA Macro CTA and PBA-b-PNVP polymers were evaluated on RAW264.7 mouse macrophage cells. The cellular viability was found to be 60.31% and 77.83% at 250 μM concentration, respectively for the two polymers. The viability was found more at high concentrations of polymers. The mechanism of cell death associated with these polymers was further evaluated in terms of apoptosis and necrosis on MCF-7 cell lines. Both the polymers induced apoptotic-like changes in MCF-7 cells. © 2019 Elsevier Ltd
Trithiocarbonate-mediated RAFT synthesis of a block copolymer: Silver nanoparticles integration and sensitive recognition of Hg2+
(Springer Science and Business Media Deutschland GmbH, 2023) Koushik Nandy; Arti Srivastava; Shere Afgan; Rajesh Kumar; Dharmendra Kumar Yadav; Vellaichamy Ganesan
Heavy metal ions, such as Hg2+, pose severe risks to the environment and human health. Therefore, sensitive determination of Hg2+ is necessary. Methyl methacrylate (MMA) and 2-acrylamido-2-methylpropane sulfonic acid (AMPS) are used for the preparation of poly(MMA) (PMMA), poly(AMPS) (PAMPS), and a block copolymer, PMMA-b-PAMPS. The PMMA-b-PAMPS is further used for the synthesis of a silver nanocomposite, represented as Ag–(PMMA-b-PAMPS). The homopolymerization of MMA and AMPS is achieved by reversible addition-fragmentation chain transfer methodology using benzyl ethyl trithiocarbonate as a chain transfer agent. The synthesized polymers are characterized by several techniques including scanning electron microscopy (SEM) and X-ray diffraction (XRD). The Ag–(PMMA-b-PAMPS) is characterized by SEM, XRD, transmission electron microscopy, X-ray photoelectron spectroscopy, and electrochemical techniques. Further, Ag–(PMMA-b-PAMPS) is exploited to construct an electrochemical sensing platform on a glassy carbon electrode surface for the sensitive determination of toxic Hg2+ present in trace amounts. The electrochemical characteristics of Ag–(PMMA-b-PAMPS) are analyzed with and without Hg2+ using cyclic voltammetry in 0.1 M pH 7.0 phosphate buffer at 20 mVs−1 scan rate. © 2022, The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.