Studies on preparation and formation mechanism of poly(lactide-co-glycolide) microrods via one-step electrospray and an application for drug delivery system

Rod-like microparticles are important drug delivery systems for their large specific surface area and high cell uptake rate. However, complex preparation methods, such as mechanical stretching and cutting after electrospinning restrict applications of rod-like microparticles. In this study, uniformly sized microrods were fabricated via one-step electrospray by using poly(lactide-co-glycolide) (PLGA) solutions with low viscosity, mainly low concentration, and low molecular weights. In contrast to previous results that polymer beads are usually obtained with low-concentration precursor solutions, we prepared 0.5–2.0 μm diameter and 4–20 μm long microrods when the concentration of the solution and molecular weight of the polymer were further decreased. Moreover, the aspect ratio of the microrods decreased significantly after upregulating the loading voltage, adding salt, and using high permittivity solvents. It is suggested that the formation of microrods with an aspect ratio of 4.51·N (N = 1, 2, 3…) was based on the surface wave theory, which was tallied with the experimental data. Furthermore, the doxorubicin(DOX)@PLGA microrods showed higher entrapment efficiency and drug-loading capacity as a drug delivery system compared with those of DOX@PLGA microspheres. Microrods have the potential for a broader range of applications in biomedicine due to the easy preparation process of one-step electrospray.