Fmoc-D-Glu-OMe

In this study, hydrogel-silver nanocomposites have been synthesized by a unique methodology, which involves formation of silver nanoparticles within swollen poly (acrylamide-co-acrylic acid) hydrogels. The formation of silver nanoparticles was confirmed by transmission electron microscopy (TEM) and surface plasmon resonance (SPR) which was obtained at 406 nm. The TEM of hydrogel-silver nanocomposites showed almost uniform distribution of nanoparticles throughout the gel networks. Most of the particles, as revealed from the particle-size distribution curve, were 24-30 nm in size. The X-ray diffraction pattern also confirmed the face centered cubic (fcc) structure of silver nanoparticles. The nanocomposites demonstrated excellent antibacterial effects on Escherichia coli (E. coli). The antibacterial activity depended on size of the nanocomposites, amount of silver nanoparticles, and amount of monomer acid present within the hydrogel-silver nanocomposites. It was also found that immersion of plain hydrogel in 20 mg/30 ml AgNO(3) solution yielded nanocomparticle-hydrogel composites with optimum bactericidal activity.

Poor mechanical properties of chitosan hydrogels limit their applications as the wound dressing. To overcome this drawback, we abandoned the traditional glacial acetic acid method but adopted a LiOH/urea solvent system to synthesize chitosan hydrogel. Then reductive Ag nanoparticles were integrated into the chitosan hydrogel networks, aiming at reinforcing the mechanical properties and improving the antibacterial properties of chitosan hydrogel. The synthesized hydrogels were subsequently characterized using the FTIR, XRD, SEM, and TEM. In addition, swelling characteristics, mechanical properties, antibacterial abilities as well as wound healing efficacy on Sprague-Dawley rats were evaluated. The results showed that the novel hydrogel exhibited porous three-dimensional network and ultrahigh mechanical properties due to the inter-molecular and intra-molecular interactions. The compressive strength was 15.95 ± 1.95 MPa, >100 times stronger than that of the control group. Meanwhile, the hydrogels still remained structural integrity even if the strain exceeded 90%. Furthermore, compared with the controls, the hydrogels exhibited more excellent antibacterial performance and significantly (p < 0.05) increased the rate of the re-epithelialization and collagen deposition, effectively accelerating the wound healing. Therefore, the synthesized hydrogel with ultrahigh mechanical properties will be found potential applications in the fields of biomedicine.

In this work, gum acacia (GA)/poly(sodium acrylate) semi-interpenetrating polymer networks (Semi-IPN) have been fabricated via free radical initiated aqueous polymerization of monomer sodium acrylate (SA) in the presence of dissolved Gum acacia (GA), using N,N'-methylenebisacrylamide (MB) as cross-linker and potassium persulphate (KPS) as initiator. The semi-IPNs, synthesized, were characterized by various techniques such as X-ray diffraction (XRD), thermo gravimetric analysis (TGA) and Fourier transform infrared (FTIR) spectroscopy. The dynamic water uptake behavior of semi-IPNs was investigated and the data were interpreted by various kinetic models. The equilibrium swelling data were used to evaluate various network parameters. The semi-IPNs were used as template for the in situ preparation of silver nanoparticles using extract of Syzygium aromaticum (clove). The formation of silver nanoparticles was confirmed by surface plasmon resonance (SPR), XRD and transmission electron microscopy (TEM). Finally, the antibacterial activity of GA/poly(SA)/silver nanocomposites was tested against E. coli.