Achieving Long-Term Sustained Drug Delivery for Electrospun Biopolyester Nanofibrous Membranes by Introducing Cellulose Nanocrystals.

Electrospun nanofibrous membranes of poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) seems not to be ideal for biomedical applications because of their hydrophobicity, and high crystallinity, as well as weak mechanical properties. It is found that hydrophilic drug such as tetracycline hydrochloride (TH) generally is located on the hydrophobic surface of electrospun PHBV nanofibrous membranes, leading to fast drug release. Therefore, we used cellulose nanocrystals (CNCs) as rigid organic nanofillers for PHBV nanofibrous membranes to enhance their mechanical, thermal, and hydrophilic properties. The influences of the CNC contents on microstructures and properties of composite nanofibrous membranes were studied. It is found that at 6 wt % CNC content, the increase of tensile strength by 125%, Young's modulus by 110%, and maximum decomposition temperature (Tmax) by 24.3 °C could be achieved, which could be contributed to strong hydrogen bonding between PHBV and CNCs. Moreover, with the introducing of the hydrophilic CNCs, the hydrophilicity of composite nanofibrous membranes was improved gradually. More importantly, good cytocompatibility, high drug loading and long-term sustained release property of composite nanofibrous membranes could be achieved. The maximum drug loading and drug loading efficiency were 25 and 98.8%, respectively, and more than 86% drug content was delivered within 540 h for the nanofibrous composite membranes with 6 wt % CNC content.