Biodegradable 'intelligent' materials in response to chemical stimuli for biomedical applications

Biodegradable stimuli-responsive materials, which exhibit large and sharp physical-chemical changes in response to small physical or chemical stimuli, are attracting increasing interests because of their potential applications in biomedical fields, such as transient implants, drug delivery carriers, and tissue engineering scaffolds. Our previous review (see page 493 of issue 4) summarized those biodegradable 'intelligent' materials that respond to physical stimuli, such as temperature, ultrasound, and magnetic field. Biodegradable 'intelligent' materials that could respond to chemical stimuli, such as pH and specific molecules, have also been studied intensively and significant progress in this field has been achieved. As a single stimulus-responsive property would limit practical application, multi-stimuli-responsive materials are receiving increasing interest and considerable attention.

This review summarizes the development of biodegradable 'intelligent' materials in response to chemical stimuli and to dual stimuli; their potential biomedical applications are also introduced. A detailed analysis of publications and patents on such materials in recent years is presented.

Most of biodegradable stimuli-responsive materials are currently still at a developmental research stage. Further work is required to improve the responsive properties between the materials and the biological environments, so that the clinical applicability of such devices could be successful. We hope that our review will be helpful in the future development of new stimuli-responsive biodegradable polymers or polymeric systems that can be used reliably in real-life applications.