Top-Down Approach for the Preparation of Highly Porous PLLA Microcylinders

A wide range of particles have been developed for different applications in drug-delivery, tissue engineering, or regenerative medicine. In contrast to traditional spherical particles, nonspherical (e.g., cylindrical) particles possess several structural and morphological advantages that make them attractive for specific applications. Here, we developed a top-down approach to process electrospun fibers into microsized cylinders (i.e., microcylinders) with high specific surface area and with or without surface porosity. To obtain these microcylinders, poly(l-lactic acid) (PLLA) solutions were subjected to electrospinning, followed by an aminolysis-based chemical scission procedure. The morphology, structure, and chemical composition of the microcylinders were then characterized. The specific surface area and surface porosity of the microcylinders were controlled by the volatility of the solvents, and their length was dependent on the duration of the aminolysis reaction. During aminolysis, the microcylinders became functionalized with amine groups, enabling potential further modifications by grafting with compounds containing desired chemical groups, for example, carboxyl, carbonyl, or hydroxyl functional groups. Additionally, the microcylinders showed in vitro biocompatible properties related to cell viability. These data demonstrate that PLLA microcylinders with high specific surface area, optional surface porosity, amine-based functional handles granting additional functionalization, and cytocompatible properties are candidate materials for future biomedical applications.