Synthesis and fabrication of antibacterial hydrogel beads based on modified-gum tragacanth/poly(vinyl alcohol)/Ag0 highly efficient sorbent for hard water softening.

In the current study, hard water softening for the removal of Ca2+ and Mg2+ ions was performed using hydrogel beads based on Gum Tragacance (GT) modified by using 2-acrylamido-2-methyl-1-propanesulfonic acid (AMPS) and poly(vinyl alcohol). The antibacterial spherical hydrogel beads were fabricated by instantaneous gelation of well dispersed mixture of poly(AMPS)-g-GT (1 g), poly(vinyl alcohol) (PVA, 1 g) flocculent, green-synthesized silver metal nanoparticles (AgNPs, 10 mg), and graphene oxide (GO, 10 mg) in the acetone solution of boric acid and then transferring into the different amounts (0.5-2.5 mL) of acidic solution of glutaraldehyde (GA) as cross-linker. The beads were fully characterized and their adsorption behavior matched well with the pseudo-second-order kinetic and the Langmuir isotherm models with the maximum adsorption of Ca2+(114.18 mg g-1) and Mg2+(162.46 mg g-1). The removal ability of the beads decreased by 6% after four adsorption/desorption cycles. The antibacterial performance of the hydrogel beads was also investigated against Gram-positive and Gram-negative bacteria.

Preparation of spherical porous hydrogel beads based on ion-crosslinked gum tragacanth and graphene oxide: Study of drug delivery behavior.

In this study, new spherical pH-sensitive porous hydrogel beads were prepared based on the water-soluble gum tragacanth (GT) polysaccharide and graphene oxide (GO) nanosheets by using Ca+2 and Ba+2 ions as crosslink agents, calcium carbonate particles as solid porogen, and Rivastigmine (RIV) as a model drug. The prepared hydrogel beads were characterized by FE-SEM, XRD, FTIR, BET, and TGA techniques. The swelling behavior of the beads was affected by cross-linker content, type of cross-linker, composition of beads, and pH. These hydrogel beads exhibited well pH-sensitivity during drug release investigation under simulated gastric (<45% at pH 1.2) and intestinal (∼97% at pH 7.4) media. The cytotoxicity test was performed on human fibroblast cells using MTT assay. The results indicated that cell survival rate was more than 98% in <125 µg/mL beads concentration. Incorporating of GO in the hydrogel increased the swelling capacity, entrapment efficiency, and ensuring a controlled release of the entrapped drug.

Synthesis of modified gum tragacanth/graphene oxide composite hydrogel for heavy metal ions removal and preparation of silver nanocomposite for antibacterial activity.

New composite hydrogels were synthesized based on gum tragacanth (GT) carbohydrate and graphene oxide (GO). GT was sulfonic acid-functionalized and cross-linked by using 2-acrylamido-2-methylpropanesulfonic acid (AMPS) and N,N'-methylenebisacrylamide (MBA) monomers and ceric ammonium nitrate (CAN) as an initiator. The prepared hydrogels were characterized by Fourier transform infrared spectrum (FT-IR), field emission scanning electron microscope (FE-SEM), energy dispersive X-ray spectroscopy (EDS), X-ray diffraction (XRD) and thermogravimetric analysis (TGA). Adsorption process for removal of heavy metal ions has followed the pseudo-first-order kinetic model and fitted well with the Langmuir model. The maximum adsorption capacity (Qm) was 142.50, 112.50 and 132.12mgg-1 for Pb(II), Cd(II), and Ag(I), respectively. The removal percentage decreased slightly after several adsorption/desorption cycles. The adsorbed Ag(I) ions in hydrogel were transformed to Ag0 nanoparticles (with a narrow distribution and mean size of 13.0nm) by using Achillea millefolium flower extract. The antibacterial performance of the Ag0 nanocomposite hydrogel was also investigated.