Advancements in Porous Silicon Biosensors for Point of Care, Wearable, and Implantable Applications.

Biosensors play a critical role in modern diagnostics, offering high sensitivity and specificity for detecting various relevant clinical analytes as well as real-time monitoring and integrability in point-of-care (POC) platforms and wearable/implantable devices. Among the numerous materials used as biosensing substrates, porous silicon (pSi) has garnered significant attention due to its tunable properties, ease of fabrication, large surface area, and versatile surface chemistry. These attributes make pSi an ideal platform for transducer development, particularly in the fabrication of optical and electrochemical biosensors. This review explores the various stages of the design of a pSi-based biosensor starting from pSi fabrication, followed by a deep study about the stabilization and functionalization techniques providing a comparative analysis of their performance. Moreover, we survey the reported designs categorized as optical and electrochemical sensors, presenting a critical evaluation of their analytical validity as well as identifying the challenges of bringing these devices to the clinical practice. By bridging existing knowledge gaps, this review aims to inspire future innovation, providing valuable insights into how pSi-based biosensors can be further optimized for noninvasive diagnostics, personalized healthcare, and early disease detection leading to a doable commercialization.