Advanced functionalization of polyhydroxyalkanoate via the UV-initiated thiol-ene click reaction

Abstract

Polyhydroxyalkanoates (PHAs) incorporating vinyl-bearing 3-hydroxyalkanoates were prepared in 8.5-12.9 g·L -1 yield. The molar ratios (0-16 mol%) of the vinyl-bearing 3-hydroxyalkanoate derivatives were controlled by the continuous feeding of undecylenate at various concentrations. Subsequently, the PHAs were functionalized by UV-initiated thiolene click reaction and chemical modification. 1 H NMR spectra suggested that 3-mercaptopropionic acid and 2-aminoethanthiol were successfully introduced into the vinylbearing PHA. Subsequently, chemical modification using fluorescein or a fibronectin active fragment (GRGDS) was attempted. The former yielded a PHA derivative capable of emitting fluorescence under UV irradiation, which was useful for determining the miscibility of PHA in a composite film comprising poly-ʟ-lactic acid (PLLA) and PHA. In the latter case, PHA bearing GRGDS peptides exhibited cell adhesiveness, suggesting that its biocompatibility was improved upon peptide introduction. Taken together, the UV-initiated thiol-ene click reaction was demonstrated to be useful in PHA modification.

When microbial biotechnology meets material engineering

“…Adhesiveness of PHA was enhanced by the introduction of a fibronectin active fragment (GRGDS peptide) by a multi‐step synthesis (Tajima et al ., 2016). Additionally, Na‐alginate was functionalized by grafting with vinyl sulfonic acid in the presence of a thiourea/peroxydiphosphate system or with polyacrylamide under microwave irradiation to improve its effectiveness as a flocculant for water treatment applications (Szabó et al ., 2020a).…”

Polyhydroxyalkanoates (PHA)-based responsive polymers

“…In another report, 3-mercaptopropionic acid-bearing carboxylic and 2-aminoethanthiol bearing amine groups introduced as thiol compound onto unsaturated medium-chain length PHA produced from undecylenate before thiol click reaction, as reported by Tajima et al [139] Both components were treated separately by different click chemistry pathways. Carboxylic-bearing PHA was treated with 1-ethyl-3-(3-dimethyl aminopropyl) carbodiimide hydrochloride (EDC) to introduce active fibronectin fragment (GRGDS); meanwhile, TEA catalyzed amine-bearing PHA to introduce fluorescein.…”

UV-mediated Thiol-ene Polyol Functionalization for Synthesis of Biobased Waterborne Polyurethanes

“…UV-mediated thiol-ene chemistry has been the subject of increased interest in polymer synthesis, crosslinking and functionalization [23][24][25][26][27][28][29][30] . Crosslinked hydrogels for biomedical applications were formed via photopolymerization of functionalized PEG and bis-cysteine peptides [31] .…”