Cancer is one of the leading causes of death in the world and protein therapeutics play an important role in combating this disease. Novel nanocarriers are needed for optimal delivery, enhanced therapeutic effect, and protection of proteins. Poly Lactic-co-Glycolic Acid (PLGA) nanoparticles are commonly used, since they are non-toxic, biodegradable, and allow for the sustained release of the active pharmaceutical ingredient (API). Accurate quantification of the therapeutic inside these nanocarriers is essential for further development and precise in vivo experiments, especially for determining the correct therapeutic dose. Bicinchoninic acid (BCA) assay is one of the most popular methods of protein quantification, known for its low sensitivity to common surfactants. However, large discrepancies between published results are often observed, with determined protein encapsulation efficiencies (EE) varying from 20 to 80%. We investigate the interference of excipients or the combination of excipients, on accurate EE determination of PLGA nanoparticles using the micro BCA assay. The EE was determined using multiple methods: by measuring the un-encapsulated protein (indirect approach) and directly by extracting the protein using sodium hydroxide and dimethyl sulfoxide. We show differences between the methods, highlight the most common pitfalls, and show the importance of using correct standards in assessing EE.

Among the most promising technologies for sustained drug delivery systems are core-shell nanofibres prepared by electrospinning. However, the most common method for the production of those, coaxial electrospinning, suffers from extremely low flow rates limiting the practical applications of such fibres. Emulsion electrospinning, on the other hand, enables the use of the high-throughput needle-less electrospinning devices for the production of the core-shell nanofibres with active pharmaceutical ingredients embedded and protected in their core. The development of such drug delivery systems for the applications in bone regeneration is further challenged by the need for the inorganic additives meant to stimulate the regeneration of the bone. The main objective of this work is to develop a high-throughput electrospinning method for the production of hybrid (organic-inorganic) and bioactive scaffolds needed for bone regeneration. We demonstrate the importance of the formulation, e.g., presence of surfactants, on the stability of the emulsion, and thus on electrospinning. Our work is an important step forward towards the high-throughput production of complex multi-material scaffolds for sustained drug delivery.