Synthesis and stability of resveratrol-gold nanoparticle-polyethylene glycol-folic acid conjugates

Objective: Gold nanoparticles (AuNPs) can be used as targeted drug delivery systems, however, AuNPs have high surface energy and easily aggregate, thus negatively impacting nanoparticle stability. Therefore, it is necessary to add a stabilizing agent to AuNPs. To synthesize AuNPs stabilized by polyethylene glycol conjugated to folic acid [FA], thus creating a model drug (resveratrol [RSV]) carrier that targets FA receptors on cancer cells. Methods: AuNPs were synthesized using the Turkevich method and stabilized by adding FA conjugated to polyethylene glycol [PEG]. After RSV was loaded, the conjugate was physically characterized and subjected to stability tests. Results: The RSV-AuNP had an average particle size of 51.97 nm [polydispersity index [PDI] 0.694, zeta potential - 24.6 mV). The RSV-AuNP-PEG-FA conjugate (RSV-AuNP-PEG-FA) had an average particle size of 195.6 nm (PDI=0.233, zeta potential=-21.1 mV). Stability tests showed that RSV-AuNP-PEG-FA was more stable than RSV-AuNP. Furthermore, RSV-AuNP-PEG-FA and RSV-AuNP were more stable in buffer pH 7.4 and bovine serum albumin 2% than in buffer pH 4, cysteine 1%, and NaCl 0.9% solutions. Conclusion: PEG-FA conjugates can improve the stability of RSV-loaded AuNP.