Abstract:
Surgical sutures and staples are usually used to close wounds and improve wound healing process in our body. Nevertheless, they are still invasive and may cause additional damage to the tissues and cannot prevent body fluid or air leakage. They are not suitable for microsurgical procedures in a limited surgical site. Tissue adhesive or so-called “bio-glue” becomes an interesting alternative as it enables wound healing via the adhesion among tissues as well as between tissues to non-tissue surfaces. In this research, two polymeric hydrogel systems were developed to be used as bio-glue. The first system is based on a synthetic polyphosphoester, one of biodegradable and biocompatible polymer which was synthesized from two monomers namely, 2-isopropoxy-1,3,2-dioxaphospholane-2-oxide (IPP) and protected N-tyrosine-m-ester phospholane amidate (P-TMP) followed by deprotection. It was anticipated that the resulting random copolymer of poly(TMP-r-IPP) would undergo tyrosine crosslinking upon visible light irradiation in the presence of [RuII(bpy)3]²⁺ and sodium persulfate (SPS) to form soft gel that can be applied as bio-glue. Unfortunately, we cannot successfully purify P-TMP in due course so that the investigation on the copolymerization and gelation cannot be fulfilled. The second system is based on naturally derived polysaccharides. Tyrosine-modified alginate (OAT) and quaternized chitosan (QC) were first prepared by chemical modification of alginate and chitosan, respectively. It was expected that OAT and QC would form a double network hydrogel. Primary crosslinking of imine bonds took place between aldehyde groups in the OAT and amino groups in the QC while the secondary crosslinking was formed via visible light-induced gelation of tyrosine units in the AOT. Preliminary investigation suggested that OAT with 16.8% substituted tyrosine seems to be a promising candidate to be further used for gel formation as it is water soluble with up to 2%w/v and it can form gel within 30 s.
