Synthesis and stability test of resveratrol-conjugated gold nanoparticle with polyvinyl alcohol stabilization

Objective: Gold nanoparticles (AuNPs) have been developed as a promising effective site-specific drug to increase drug efficacy and reduce potential side effects. However, AuNPs are unstable because they easily aggregate. This study aims to produce stable resveratrol (RSV)-conjugated AuNPs using polyvinyl alcohol (PVA). Methods: AuNPs were synthesized using the Turkevich method, which involves the reduction of chloroauric acid with sodium citrate as a reductor. AuNPs were then modified with PVA as a stabilizing agent and conjugated with RSV as a drug model in the carrier system. The formed conjugates were characterized using ultraviolet-visible spectrophotometry, Fourier transform infrared spectroscopy, particle size analysis, and high-performance liquid chromatography. Furthermore, stability tests were performed in various media (2% bovine serum albumin [BSA], 1% cysteine, phosphate-buffered saline [PBS] pH 4, PBS pH 7.4, and 0.9% NaCl) for 28 days. Results: RSV-AuNPs-PVA had a particle size of 78.75 nm, with polydispersity index (PDI) of 0.356, zeta potential of -36.1 mV, and highest entrapment efficiency of 78.1%±0.7. RSV-AuNPs without PVA stabilization had a particle size of 51.97 nm, with PDI of 0.694 and zeta potential of -24.6 mV. The results of the stability tests demonstrated that RSV-AuNPs-PVA was stable in 2% BSA, PBS pH 7.4, PBS pH 4, and NaCl 0.9% and were unstable in 1% cysteine. RSV-AuNPs without PVA were stable in 2% BSA and PBS pH 7.4 and unstable in 1% cysteine, PBS pH 4, and 0.9% NaCl. Conclusion: PVA can improve the physical stability of RSV-AuNPs conjugates.