Implantable Biosensors with Drug Release Capabilities

Abstract

Implantable biosensors capable of both detecting physiological analytes and releasing therapeutic agents in response to detected signals represent a convergence of diagnostics and therapy that has been pursued for decades but is only now approaching clinical translation. The appeal is direct: a device that senses the need for a drug and delivers it, autonomously, at the site of action, eliminates the patient compliance requirement, the pharmacokinetic lag of systemic administration, and the off-target exposure that systemic delivery inevitably generates. This study introduces the Implantable Biosensor-Drug Release Assessment Framework (IBDRAF), evaluating five integrated biosensor-drug release platform types -- electrochemical biosensor with hydrogel drug reservoir (EC-HDR), optical biosensor with stimuli-responsive polymer release (OPT-RPR), piezoelectric biosensor with ultrasound-triggered release (PZ-UTR), MEMS-based biosensor with microfluidic drug delivery (MEMS-MDD), and nanomaterial biosensor with stimulus-responsive nanoparticle release (NANO-RNP) -- across four clinical application contexts: closed-loop glucose monitoring with insulin release, inflammatory biomarker detection with anti-inflammatory drug release, cardiac biomarker monitoring with antiarrhythmic and anticoagulant release, and pain biomarker detection with analgesic release. Performance was scored using the Biosensor-Drug Integration Score (BDIS), a weighted composite of sensing accuracy (0.30), drug release precision (0.20), biointegration (0.20), device longevity (0.15), and miniaturisation feasibility (0.15). MEMS-based microfluidic platforms achieved the highest BDIS (0.892), combining strong sensing accuracy (0.900) with the best drug release precision (0.920), device longevity (0.900), and miniaturisation (0.900). Nanomaterial platforms ranked second (0.889) with the highest sensing accuracy (0.940) and excellent biointegration (0.900). Electrochemical hydrogel platforms scored third (0.883), with the most mature clinical translation evidence. Piezoelectric ultrasound-triggered systems achieved the best drug release precision (0.940) but were constrained by biointegration (0.820) and miniaturisation (0.780) challenges