Abstract
Hollow core/shell carbon microparticles, denoted HCSC600, are synthesized from yeast cells by coating the cells with silica shells, and then pyrolyzing the silica-protected yeast cells at 600 °C, and finally etching the silica shells off of the carbonized products. The microparticles possess a yolk/shell structure with very large interior hollow spaces and interconnected porous structures—structural features that are generally useful for adsorption and release of drug molecules. The microparticles are characterized by various methods, including scanning electron microscopy, transmission electron microscopy, nitrogen gas adsorption/desorption and X-ray photoelectron spectroscopy. Their adsorption properties are evaluated by using rhodamine B (RhB) as a model drug and the poorly soluble drug fenofibrate (FFB), a prodrug of fenofibric acid, which is widely used to treat hypertriglyceridemia. Compared with the control material prepared from yeast cells without silica coating (named YCC600), the HCSC microparticles showed much higher adsorption capacity for both compounds, suggesting that the silica coating is important not only for controlling the morphology of the particles but also for giving them high surface area. Furthermore, it is found that the HCSC600 material loaded with FFB allows the drug molecules to be released faster and better than they are from the bulk drug. The results indicate that HCSC microparticles have great potential to serve as drug delivery vehicles, especially for poorly bioavailable drugs such as FFB, for biomedical applications.