Size-controlled synthesis of bioinspired polyserotonin nanoparticles with free radical scavenging activity

Polyserotonin-based nanoparticles are a new class of bioinspired nanomaterial with recently demonstrated therapeutic potential for future clinical applications. It is therefore important to establish a robust and rapid method of synthesizing polyserotonin nanoparticles (PSeNP) in the size range ideal for in vivo utilization. Since the formation of PSeNP is base-catalyzed, here we report the influence of solution pH, in the presence of different base systems, on the kinetics of PSeNP formation and physico-chemical properties of the resulting nanoparticles. We show that the rate of formation and the size of PSeNP depend on both the nature of the base and the initial pH of the reaction. We have also improved the kinetics of particle formation by performing the synthesis at an elevated temperature (60 °C), leading to a dramatic reduction in synthesis time from days to hours. This presents a significant advance in the efficiency of PSeNP synthesis and provides a facile approach in tuning the size of nanoparticles to suit various applications. Furthermore, we show that similar to serotonin, PSeNP also exhibits free radical scavenging property. Our results demonstrate that PSeNP has the potential to become a key player in the advancement of nanotechnology-mediated antioxidative therapy.