Development and Characterization of Porous PDMS Microneedles

This study aimed the development and characterization of polydimethylsiloxane (PDMS) porous microneedles (MNs) cast with silica nanoparticles as porogenic material for biomedical applications. To produce the porous PDMS MNs, different concentrations of silica nanoparticles were cast into PDMS, followed by chemical etching to remove the casted material and produce a porogenic network. This chemical etching was achieved using NaOH and it included initial steps for homogenization of the silica material dispersed in ethanol mixed with PDMS and followed by the evaporation of the solvent. Afterwards, the morphology, wettability, air permeability, swelling, porosity, surface chemistry, and mechanical characteristics of the developed porous PDMS MNs were investigated. The results showed that the porosity and mechanical properties of porous MNs could be tailored by varying the porogenic material concentration. Overall, the results of this study suggest that PDMS porous MNs have great potential as platforms for biomedical applications such as drug delivery, designed with a simple and rapid procedure that can be tuned in the detriment of the application.