Preparation of bovine serum albumin nanospheres <i>via</i> desolvation: a study of synthesis, characterization, and aging

Serum albumin has myriad uses in biotechnology, but its value as a nanocarrier or nanoplatform for therapeutics is becoming increasingly important, notably with albumin-bound chemotherapeutics. Another emerging field is the fabrication of biopolymeric nanoparticles using albumin as a building block to achieve highly-tunable nonimmunogenic capsules or scaffolds that may be cheaply and reliably produced. The aim of this study was to characterize and optimize the desolvation process used for fabrication of albumin nanoparticles under ambient conditions, studying both glutaraldehyde (GT) and glucose (GLU) as crosslinking agents and the effect of various synthesis conditions including pH, electrolyte concentration, and rate of desolvation on particle size and stability. Particle size, polydispersity index, and zeta potential were investigated, morphology was examined using scanning electron microscopy (SEM), and long-term stability and degradation modes were studied using dynamic light scattering (DLS) and transmission electron microscopy (TEM). It was determined that the optimized synthesis procedure for synthesis of Bovine Serum Albumin (BSA) nanoparticles at the investigated scale under ambient conditions was addition of ethanol at a rate of 0.625 mL min^-1<i>via</i> infusion against the vial wall and a pH of 9 with the addition of no other electrolytes. Optimized BSA nanoparticles were synthesized at a size of 86 ± 3.7 nm (<i>σ</i> = 1.85) using glutaraldehyde as a crosslinker and a size of 92 ± 1.9 nm (<i>σ</i> = 0.95) using glucose as a crosslinker with polydispersity indices of 0.08 and 0.05, respectively. Nanoparticles synthesized <i>via</i> the optimized procedure, using both crosslinkers, were found to maintain colloidal stability significantly longer than cases previously reported in the literature, with insignificant changes in hydrodynamic size many months after synthesis.