Chitosan-based drug delivery systems: Current strategic design and potential application in human hard tissue repair

Direct utility of molecular drugs has been hindered in dental and bone engineering because of their short-term biological effects in vivo, fast metabolism or difficulties in achieving drug delivery targetability. To solve these problems, drug delivery systems (DDSs) have been studied extensively in recent years. As a natural polysaccharide, chitosan (CS) has been widely studied as a bioactive carrier for DDSs due to its excellent biocompatibility, biodegradability, polycation characteristic, bioadhesion, bacteriostasis and simplicity of modification. Numerous new designs of CS-based DDSs combining the chitosan carrier with natural or synthetic polymers and bioactive molecules have been fabricated to promote remineralization and osteogenesis. This paper presents the main properties of CS as a carrier for human hard tissue repair and has tried to review the current CS-based applications for bone regeneration and dental repair.