Tóm tắt

Amyloids are fibrillar structures formed due to protein aggregation or misfolding when the molecules undergo a rnconformational change from α-helix to β-sheet. Although this self-assembly is associated with many neurode-generative diseases in vivo, the highly ordered amyloidic structures formed in vitro are ideal scaffolds for many rnbionanotechnological applications. Amyloid fibrillar networks under specific stimuli can also form stable hy-drogels. We have used bovine serum albumin (BSA) as a model amyloidogenic protein to obtain thermally- rninduced hydrogels that display tunable sol-gel-sol transitions spanning over minutes to days. High concentra-tions of BSA (14–22% w/v) were heated at 65 °C for less than 3 min without any cross-linking agent to yield soft, rninjectable gels that were non-toxic to mammalian cells. A detailed investigation of temperature, concentration, rnincubation time and ionic strength on the formation and reversal of these gels was carried out using visual rninspection, rheology, electron microscopy, fluorescence spectroscopy, UV–visible spectroscopy and circular di-chroism spectroscopy. The optimum gelation temperature (Tg) for phase reversal of BSA gels was found to lie rnbetween 60 and 70 °C. An increase in protein concentration led to a reduction in the gelation time and increase rnin the gel-to-rev sol transition time. Gels heated for longer duration than their minimum gelation time yielded rnirreversible gels suggesting that low incubation periods were favourable for partial protein denaturation and rnhydrogel formation. This was supported by time-resolved secondary and tertiary structural ensemble studies. rnFurther, the hydrogel networks demonstrated a zero-order drug release kinetics and the rev sol was found to be rncytocompatible with HaCaT skin cell lines. Overall, our approach demonstrates rapid, crosslinker-free thermo-responsive BSA gelation with wide tunability and control on the time and material property, ideal for topical rndrug delivery applications.