Advanced smart biomaterials and constructs for hard tissue engineering and regeneration

Abstract

Hard tissue repair and regeneration cost hundreds of billions of dollars annually worldwide, and the need has substantially increased as the population has aged. Hard tissues include bone and tooth structures that contain calcium phosphate minerals. Smart biomaterial-based tissue engineering and regenerative medicine methods have the exciting potential to meet this urgent need. Smart biomaterials and constructs refer to biomaterials and constructs that possess instructive/inductive or triggering/stimulating effects on cells and tissues by engineering the material’s responsiveness to internal or external stimuli or have intelligently tailored properties and functions that can promote tissue repair and regeneration. The smart material-based approaches include smart scaffolds and stem cell constructs for bone tissue engineering; smart drug delivery systems to enhance bone regeneration; smart dental resins that respond to pH to protect tooth structures; smart pH-sensitive dental materials to selectively inhibit acid-producing bacteria; smart polymers to modulate biofilm species away from a pathogenic composition and shift towards a healthy composition; and smart materials to suppress biofilms and avoid drug resistance. These smart biomaterials can not only deliver and guide stem cells to improve tissue regeneration and deliver drugs and bioactive agents with spatially and temporarily controlled releases but can also modulate/suppress biofilms and combat infections in wound sites. The new generation of smart biomaterials provides exciting potential and is a promising opportunity to substantially enhance hard tissue engineering and regenerative medicine efficacy.

Bone repair: a new generation of smart biomaterials

Smart biomaterials that are able to instruct bone repair can overcome some of the shortcomings of bone grafting and meet the growing need for hard tissue regeneration in ageing populations. Hockin Xu at the University of Maryland in Baltimore, United States, and colleagues review recent advances in the development of smart biomaterials for repairing and regenerating damaged bones and teeth. They highlight scaffolds that closely mimic natural bone tissue and immunomodulatory biomaterials that can prevent infection and promote cell survival for guiding and enhancing bone regeneration. Furthermore, scaffolds with shape-memory capability and materials that provide tailored spatio-temporal delivery of drugs or bioactive agents in response to internal or external stimuli, hold great promise not only for bone tissue engineering but also for dentistry.