Keng Wooi Ng

A peptide-based hydrogel sequence was computationally predicted from the Ala-rich cross-linked domains of elastin. Three candidate peptides were subsequently synthesised and characterised as potential drug delivery vehicles. The elastin-derived peptides are Fmoc-FFAAAAKAA-NH₂, Fmoc-FFAAAKAA-NH₂, and Fmoc-FFAAAKAAA-NH₂. All three peptide sequences were able to self-assemble into nanofibers. However, only the first two could form hydrogels, which are preferred as delivery systems compared to solutions. Both of these peptides also exhibited favourable nanofiber lengths of at least 1.86 and 4.57 µm, respectively, which are beneficial for the successful delivery and stability of drugs. The shorter fibre lengths of the third peptide (maximum 0.649 µm) could have inhibited their self-assembly into the three-dimensional networks crucial to hydrogel formation.

Importance of experimental configurations for in vitro mechanical evaluation of microneedle arrays as the first-line investigation of skin insertion potential.

Microneedle patches, with needles of sub-millimeter size, are non-invasive and pain free way of drug delivery. The needles penetrate skin, pass stratum corneum, but do not penetrate tissue which contains nerves and blood vessels. In this work, a new and unique chitosan-hydrogel based composite material was formulated to produce microneedle patches and their potency for extended drug delivery was validated using methylene blue as a model drug.

This research aimed to integrate an established signalquantification technique with immunocapture microneedle arrays (MNAs) to improvebiomarker-based disease diagnostics in the skin. In this miniaturized sandwichenzyme-linked immunosorbent assay (ELISA) platform, the capture antibody wasimmobilised onto the surface of microneedles which, when inserted superficiallyinto porcine skin, captured endogenous porcine immunoglobulin G (IgG) intradermally. Signal development was achieved by incubating the microneedles ino-phenylenediamine (OPD) solution in a 384-well microplate and measuring theabsorbance in a microplate spectrophotometer at 450 nm. This technique allowsfor rapid biomarker detection with high-throughput processing. Immunocapture microneedledevices such as these can be easily adapted for targeting different biomarkersor multiplexed leaving plenty of scope for future work and assay optimisation.