This study evaluated three techniques, stimulated emission depletion (STED) microscopy, atomic force microscopy (AFM), and cryogenic scanning electron microscopy (Cryo-SEM), for visualising the morphology and obtaining pore size information of agarose hydrogels (0.38, 1.0, 1.5, 2.0% agarose content). The pore size distributions were obtained using a common manual approach which was validated for Cryo-SEM data using poly(lactic-co-glycolic acid) (PLGA) nanoparticles as an internal standard. There was good agreement in pore size distribution data for agarose hydrogels with an agarose content of 1.0% and higher when using these techniques. For the 1.0% gel sample imaged using STED and Cryo-SEM, no significant difference was observed between these two techniques yielding average pore sizes of 240 and 230 nm, respectively. The average pore size values obtained from AFM images for 1.5 and 2.0% gel samples were significantly smaller by 10–15% compared to values obtained from Cryo-SEM data as predicted due to the AFM tip artefact for concave features. Pros and cons of each technique are discussed in detail.

Poly(lactic-co-glycolic acid) (PLGA) nanoparticles have been extensively studied as carriers of a wide variety of drugs. However, the variability in protocols and reporting in nanoscience represents a barrier to advances in new therapies. Recent literature has highlighted the challenge of reproducibility in biomedical research. In this study involving three researchers performing the experiments we therefore verified the repeatability and replicability of PLGA nanoparticles fabricated by the emulsion solvent evaporation method. Furthermore, we investigated how variables during synthesis, isolation, and characterisation of PLGA particles affect the reported particle size and drug encapsulation. Synthesis parameters including emulsification technique, type of polymer, and type of surfactant were investigated. In the isolation process, we tested the effect of washing and filtration. Dynamic light scattering (DLS) was used to determine the number weighted mean, z-average, and polydispersity index (PDI). Direct visualization of the particles was achieved by scanning and transmission electron microscopies. Changes in the source of energy input to the system using a sonic probe and homogeniser showed the most pronounced effect on particle size and PDI. This work has demonstrated that particle properties are affected by multiple variables involved in the synthesis and isolation processes. We provided advice for PLGA-based nanoparticle fabrication and drug encapsulation quantification as well as the minimum required information to be reported allowing reproducibility.

Aim: This work aimed to produce a membrane based on fluconazole-loaded natural rubber latex (NRL), and study their interaction, drug release and antifungal susceptibility against Candida albicans. Materials & methods: Fluconazole-loaded NRL membrane was obtained by casting method. Results: The Fourier Transform Infrared Spectroscopy showed no modifications either in NRL or fluconazole after the incorporation. Mechanical test presented low Young's modulus and high strain, indicating the membranes have sufficient elasticity for biomedical application. The bio-membrane was able to release the drug and inhibit the growth of C. albicans as demonstrated by disk diffusion and macrodilution assays. Conclusion: The biomembrane was able to release fluconazole and inhibit the growth of C. albicans, representing a promising biomaterial for skin application.