Microenvironment-responsive Smart Biomaterials in Periodontal Regeneration: A Critical Review

Abstract

Periodontitis remains one of the most prevalent chronic inflammatory conditions affecting the tooth-supporting apparatus, and conventional mechansical and pharmacological therapies frequently fail to achieve predictable regeneration of the periodontal ligament, cementum, and alveolar bone. Over the past decade, the diseased periodontal pocket has been reconceptualised not simply as a site of destruction but as a reservoir of diagnostic biochemical information, including localised acidosis, elevated reactive oxygen species, dysregulated proteolytic and phosphatase activity, and, in diabetic patients, hyperglycaemia. Microenvironment-responsive smart biomaterials exploit these endogenous cues to trigger on-demand release of antimicrobial, anti-inflammatory, and osteogenic agents precisely at the diseased site, in contrast to conventional formulations that release their payload independently of local pathology. This review synthesises the current evidence on pH-responsive, reactive-oxygen-species-responsive, enzyme-responsive, glucose-responsive, and multi-stimulus cascade-responsive biomaterial platforms, spanning hydrogels, microneedles, fibrous membranes, polymeric microspheres, inorganic nanoparticles, and vesicular carriers. Particular attention is given to how these platforms are being engineered to achieve spatiotemporally orchestrated therapeutic sequences, moving from early antimicrobial and antioxidant action, through mid-stage osteoimmunomodulation, towards late-stage tissue regeneration involving stem cell homing and angio-osteogenic coupling. The review also critically appraises translational obstacles, including manufacturing scalability, sterilisation compatibility, threshold matching to heterogeneous patient physiology, and the scarcity of controlled clinical trials. We conclude that microenvironment-responsive biomaterials constitute a scientifically coherent and clinically promising evolution beyond passive scaffolds and drug carriers, although substantial work remains before these platforms can be considered standard components of periodontal regenerative therapy.