Resveratrol-Loaded Albumin Nanoparticles with Prolonged Blood Circulation and Improved Biocompatibility for Highly Effective Targeted Pancreatic Tumor Therapy

Human serum albumin (HSA) is an intrinsic protein and important carrier that transports endogenous as well as exogenous substances across cell membranes. Herein, we have designed and prepared resveratrol (RV)-loaded HSA nanoparticles conjugating RGD (arginine-glycine-aspartate) via a polyethylene glycol (PEG) "bridge" (HRP-RGD NPs) for highly effective targeted pancreatic tumor therapy. HRP-RGD NPs possess an average size of 120 ± 2.6 nm with a narrow distribution, a homodisperse spherical shape, a RV encapsulation efficiency of 62.5 ± 4.21%, and a maximum RV release ratio of 58.4.2 ± 2.8% at pH 5.0 and 37 °C. In vitro biocompatibility of RV is improved after coating with HSA and PEG. Confocal fluorescence images show that HRP-RGD NPs have the highest cellular uptake ratio of 47.3 ± 4.6% compared to HRP NPs and HRP-RGD NPs with free RGD blocking, attributing to an RGD-mediated effect. A cell counting kit-8 (CCK-8) assay indicates that HRP-RGD NPs without RV (HP-RGD NPs) have nearly no cytotoxicity, but HRP-RGD NPs are significantly more cytotoxic to PANC-1 cells compared to free RV and HRP NPs in a concentration dependent manner, showing apoptotic morphology. Furthermore, with a formulated PEG and HSA coating, HRP-RGD NPs prolong the blood circulation of RV, increasing approximately 5.43-fold (t1/2). After intravenous injection into tumor-bearing mice, the content of HRP-RGD NPs in tumor tissue was proven to be approximately 3.01- and 8.1-fold higher than that of HRP NPs and free RV, respectively. Based on these results, HRP-RGD NPs were used in an in vivo anti-cancer study and demonstrated the best tumor growth suppression effect of all tested drugs with no relapse, high in vivo biocompatibility, and no significant systemic toxicity over 35 days treatment. These results demonstrate that HRP-RGD NPs with prolonged blood circulation and improved biocompatibility have high anti-cancer effects with promising future applications in cancer therapy.