Synthesis, characterization and antimicrobial activities of boron-starch complexes

Boron complexes of starch and starch/poly (vinyl alcohol) (PVA) hydrogels, were synthesized with or without using glutaraldehyde (GA), epichlorohydrin (EPI) and N-(aminoethyl)-aminopropyl-trimethoxysilane (Z-6020) as cross-linking agents. The obtained complexes were characterized by using Fourier transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA), scanning electron microscope (SEM) and X-ray diffraction analysis (XRD) methods. Degree of solubility, swelling and tensile strength tests were performed for the synthesized complexes. The antimicrobial activities of prepared boron-starch complexes either in powder or hydrogel form were assayed with in vitro conditions by the disc diffusion susceptibility tests for five different bacterial cultures and one fungus. Standard disks of amoxycillin/clavulanic acid (AMC), ofloxacin (OFX), netilmycin (NET), erythromycin (ER) and amphotericin B (AFB) were individually used as positive controls during antimicrobial activity testes. Inhibition zone formations confirmed that, starch/PVA hydrogel cross-linked with GA and boron complex of this hydrogel showed moderate antimicrobial activity against tested microorganisms, the latter being more efficient and more pronounced on Gram-negative than on Gram-positive bacteria. Other hydrogels and powder complexes had no antimicrobial activities against tested microorganisms. Considering all results, it could be claimed that the boron complexes of starch/PVA hydrogels cross-linked with GA might be used for biomedical applications.