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In the study, fabrication of Arabic gum (AG) hydrogels via reverse micellization method is reported. AG hydrogels were utilized as capping agents to encapsulate zinc sulphide (ZnS), and cadmium sulphide (CdS) nanoparticles via in-situ reduction. Pristine and nanocomposite hydrogels (AG-ZnS and AG-CdS) were characterized through SEM, EDX, TEM, XRD, FTIR, TGA, UV/Visible, and photoluminescence spectroscopy. The hydrogels were subjected to multiple biological assays including antimicrobial, antioxidant, and anti-diabetic formulation, in addition to biocompatibility test. The hydrogels were found to be more effective against bacterial and fungal strains. For instance, AG-ZnS exhibited excellent growth inhibition activity against Escherichia coli (ZoI: 12 ± 1.04 mm) and Candida albicans (35 ± 0.94 mm). Likewise, the nanocomposites hydrogel also displayed excellent DPPH and ABTS free radical scavenging capacity, total antioxidant capacity (TAC), and total reducing power (TRP) ability. Among the hydrogels, AG-ZnS demonstrated considerable α-amylase, and α-glucosidase inhibition potential. Above all, the hydrogels were found highly compatible with human red blood cells (hRBCs). Owing to remarkable antioxidant, antibacterial, antifungal, and bio-compatible nature, the fabricated nanocomposites hydrogels have the potential to be explored in tissue engineering, wound healing, drug delivery, and in environmentally friendly hygiene products., (Copyright © 2022 Elsevier B.V. All rights reserved.)

We report novel gum acacia (GA) based microgels composites for multifunctional biomedical application. High yield of spherical GA microgels particles within 5-50 μm size range was obtained via crosslinking the polymer in the reverse micelles of surfactant-sodium bis (2-ethylhexyl) sulfosuccinate (NBSS) in gasoline medium. The prepared microgels were then utilized for in situ silver (Ag) and cobalt (Co) nanoparticles (NPs) synthesis to subsequently produce GNAg and GNCo nanocomposite microgels, respectively. Ag and Co NPs of particle of almost less than 40 nm sizes were homogenously distributed over the matrices of the prepared microgels, and therefore, negligible agglomeration effect was observed. Pristine GA microgels, and the nanocomposite microgels were thoroughly characterized through FTIR, DSC, TGA, XRD, SEM, EDS, and TEM. The well-characterized pristine GA microgels and the nanocomposite microgels were then subjected to multiple in vitro bioassays including antioxidant, antidiabetic, and antimicrobial activities as well as biocompatibility investigation. Our results demonstrate that the prepared nanocomposites in particular GNAg microgels exhibited excellent biomedical properties as compared to pristine GA microgels. Among the prepared samples, GNAg nanocomposites were highly active against Fusarium oxysporum and Aspergillus niger that show 47.73% ± 0.25 inhibition and 32.3% ± 2.0 with IC-50 of 220 μg ml -1 and 343 μg ml -1 , respectively. Moderate antidiabetic activity was also observed for GNAg nanocomposites with considerable inhibition of 15.34% ± 0.20 and 14.7% ± 0.44 for both α-glucosidase and α-amylase, respectively. Moreover, excellent antioxidant properties were found for both the GNAg and GNCo nanocomposites as compared to pristine GA microgels. A remarkable biocompatible nature of the nanocomposites in particular GNAg makes the novel GA composites, to be exploited for diverse biomedical applications., (© 2021 Wiley Periodicals LLC.)

The size of the silica particles and morphology of hybrids were controlled in copolyimide based hybrids through amino-silane functionalization of silica particles prepared in situ through a self-catalyzed sol-gel process using atmospheric moisture. The particles were generated using tetraethoxysilane in the uncompatiblized (UPISH) system whereas a mixture of 3-aminopropyltrietoxysilane and tetraethoxysilane was used in the compatiblized Co-PI/silica hybrid (CPISH) system. The properties of resulting hybrid films were measured by Fourier Transform Infrared Spectroscopy, Scanning Electron Microscopy, Thermogravimetirc Analysis, Dynamic Mechanical Analysis and Universal Testing Machine. FTIR results confirmed the formation of silica particles and Co-PI matrix. FE-SEM images revealed spherical silica particles with sharp boundaries in UPISH; whereas nano-sized coupled silica network structures with totally different morphologies were observed in CPISH system. The CPISH system exhibited better thermal stability, higher modulus and Tg values than UPISH system. The improvement in thermal and mechanical properties has been discussed with reference to morphological changes due to incorporation of 3-aminopropyltrietoxysilane in aerobic condition and in a self-catalyzed sol-gel process. [ABSTRACT FROM AUTHOR]

Polyamide-6-based composites with pristine or functionalized multi-walled carbon nanotubes were produced using melt extrusion technique. After chemical functionalization, defect formation and attachment of carboxylic (−COOH) or amine (−NH2) groups on carbon nanotubes was confirmed from high-resolution transmission electron microscope and Fourier transform infra-red spectroscope studies. Carbon nanotubes incorporation promoted growth of α-form crystals with enhanced thermal stability through increase in crystallization temperature from 162 to 192℃. Dynamic mechanical thermal analysis (DMTA) indirectly pointed out to a homogeneous, uniform dispersion of nanotubes with reduction in free volume of the polymer, exhibiting a slight increase in glass transition temperature and a significant drop in coefficient of thermal expansion value. Composites containing 0.5 wt% NH2-carbon nanotubes show increases in elastic modulus and tensile strength by ∼60 and 76%, respectively. Uniform dispersion and high interfacial strength was manifested by drop in strain to failure and lack of evidence of carbon nanotubes debonding from the matrix. [ABSTRACT FROM AUTHOR]

Pure polyamide 6 (PA6) and polyamide 6/carbon nanotube (PA6/CNT) composite samples with 0.5 weight percent loading of pristine or functionalized CNTs were made using a solution mixing technique. Modification of nanotube surface as a result of chemical functionalization was confirmed through the presence of lattice defects as examined under high-resolution transmission electron microscope and absorption bands characteristic of carboxylic, sulfonic and amine chemical groups. Microstructural examination of the cryogenically fractured surfaces revealed qualitative information regarding CNT dispersion within PA6 matrix and interfacial strength. X-ray diffraction studies indicated formation of thermodynamically more stable α-phase crystals. Thermogravimetric analysis revealed that CNT incorporation delayed onset of thermal degradation by as much as 70 °C in case of amine-functionalized CNTs, thus increasing thermal stability of the composites. Furthermore, addition of amine-functionalized CNTs caused an increase in crystallization and melting temperatures from the respective values of 177 and 213 °C (for neat PA6) to 211 and 230 °C (for composite), respectively. [ABSTRACT FROM AUTHOR]