Chemically Cross-Linked Chitin Nanocrystal Scaffolds for Drug Delivery

Chitin nanocrystals (ChNCs), prepared by acid hydrolysis of chitin, exhibit a uniform needlelike morphology and high dispersion stability in aqueous solutions, which makes them good candidates for drug delivery. Porous ChNC scaffolds were freeze-dried from different concentrations of ChNC dispersions and then cross-linked by a reaction with glutaraldehyde. Various techniques, including scanning electron microscopy, Fourier transform infrared spectroscopy, X-ray diffraction, thermogravimetric analysis, and testing of mechanical properties, porosity, and swelling properties, were used to characterize the structure of chemically cross-linked chitin nanocrystal (XChNC) scaffolds. The compressive mechanical strength, density, porosity, and water absorption rate of XChNC scaffolds were dependent on the concentration of ChNCs. XChNC scaffolds showed interconnected pores with a mean pore size of ∼65 μm diameter. Curcumin was used as a model drug and loaded into the XChNC scaffold by encapsulation in Tween 20 micelles. The drug release period from XChNC scaffolds was determined to be 540 min in phosphate-buffered saline (PBS) at pH 5.3 and 780 min in PBS at pH 7.4. Cytotoxicity experiments using human breast adenocarcinoma cells (MCF-7) revealed that released curcumin inhibited the proliferation of MCF-7 cells. All of the results show that XChNC scaffolds exhibit great potential for tissue-engineering and drug-delivery applications.