Porous Silicon Optical Devices: Recent Advances in Biosensing Applications

Abstract

This review summarizes the leading advancements in porous silicon (PSi) optical-biosensors, achieved over the past five years. The cost-effective fabrication process, the high internal surface area, the tunable pore size, and the photonic properties made the PSi an appealing transducing substrate for biosensing purposes, with applications in different research fields. Different optical PSi biosensors are reviewed and classified into four classes, based on the different biorecognition elements immobilized on the surface of the transducing material. The PL signal modulation and the effective refractive index changes of the porous matrix are the main optical transduction mechanisms discussed herein. The approaches that are commonly employed to chemically stabilize and functionalize the PSi surface are described.

Characterization of Mechanochemical Modification of Porous Silicon with Arginine

“…Therefore, Rxn. (1) does not occur at an appreciable rate at room temperature. In the absence of any other form of activation, it must be the presence of highly reactive dangling bonds that initiates reactivity to produce H2.…”

“…The versatile chemical and physical properties of porous silicon (por-Si), including its biocompatibility, allow for applications in sensors [1], energy storage [2,3], and biomedicine [4]. Porous silicon can be formed through a variety of different methods, including regenerative electroless etching (ReEtching) [5], stain etching [6], and metal-assisted catalytic etching (MACE) [7].…”

Functionalization of Oxide‐Free Silicon Surfaces for Biosensing Applications

“…Optical biosensors include for example surface plasmon resonance sensors, [151] ellipsometric sensors [152] waveguide and interferometric sensors, [153,154] and reflectometric interference spectroscopy biosensors. [155] They represent the most common type of bioanalytical sensors and are often silicon-based.…”

Bottom-Up Synthesis of Mesoporous TiO2 Films for the Development of Optical Sensing Layers

“…Therefore, there is a growing interest in the development of new configurations of optical sensors where the interaction of the light with the analyte is maximized. To this aim, nanostructured materials arise as a remarkable solution because of their unique physicochemical features in comparison with their bulk counterparts: high surface-tovolume ratio, small size, or tunable refractive index, among many others [14]. Thus, nanostructure-based sensors show an enhanced performance (i.e., fast response time, higher sensitivity, lower limit of detection, etc.)…”