Implantable Biosensors for Chronic Disease Monitoring

Abstract

Chronic diseases -- diabetes, heart failure, chronic kidney disease, and inflammatory bowel disease -- affect over 1.7 billion people globally and require continuous monitoring of biomarkers that fluctuate hourly to daily. Current monitoring relies on intermittent blood draws, urine tests, or clinic visits that capture only snapshots of a continuously evolving disease state. Implantable biosensors offer continuous, real-time biomarker measurement from within the body -- glucose in interstitial fluid, lactate in muscle, troponin in blood, creatinine in peritoneal fluid, and calprotectin in the intestinal lumen. Continuous glucose monitors (CGMs) have demonstrated the clinical value of this paradigm: HbA1c reductions of 0.5-1.0% and 40% fewer hypoglycaemic events compared to fingerstick monitoring. Yet CGMs remain the only commercially successful implantable biosensor class, and extending the paradigm to other analytes faces challenges in sensor longevity, biocompatibility, foreign body response, power supply, and data transmission. We present the Implantable Biosensor Assessment Framework (IBAF), evaluating five sensor architectures -- electrochemical enzymatic sensors, affinity-based aptamer sensors, optical fluorescence sensors, microdialysis sampling probes, and bioelectronic neural interface sensors -- across four chronic disease targets (diabetes, heart failure, CKD, and IBD). Our Implantable Sensor Performance Score (ISPS) measures analytical accuracy, operational lifetime, biocompatibility, power autonomy, and clinical actionability. Optical fluorescence sensors achieve the highest ISPS (0.920) through superior operational lifetime (180+ days) enabled by reagentless detection, while electrochemical enzymatic sensors achieve the highest analytical accuracy (0.960) for glucose monitoring