Two-step desolvation. Coester et al. [20] reported a
two-step desolvation method to produce GNP. Here,
this method was adapted to encapsulate BSA in situ
within GNP. Briefly, 200 mg gelatin was dissolved in
distilled water (10 mL) under constant heating at 40° ±
1°C. Acetone (10 mL) was added to the gelatin
solution as a desolving agent to precipitate the high
molecular weight gelatin. The supernatant was
discarded, and the high molecular weight gelatin was
redissolved by adding distilled water (10 mL) with
stirring under constant heating at 40°C, pH 3 (by
adding 0.1 M HCL). BSA was added, followed by
dropwise addition of acetone (30 mL) to form GNP. At
the end of the process, glutaraldehyde solution (100
μL) was added as a cross-linking agent, and the
solution was stirred at 40 ± 1°C for 30 min. Solution
was centrifuged at 11790 RCF for 30 min. The
particles were purified by threefold centrifugation and
ridispersion water. After the last ridispersion,
fabricated particles were freeze-dried, and then white
freely flowing powder of BSA-loaded GNP was
obtained. The process has been described
schematically in Figure 1.