Abstract
Detection and quantification of biologically-relevant analytes using handheld platforms are important for point-of-care diagnostics, real-time health monitoring, and treatment monitoring. Among the various signal transduction methods used in portable biosensors, photoelectrochemcial (PEC) readout has emerged as a promising approach due to its low limit-of-detection and high sensitivity. For this readout method to be applicable to analyzing native samples, performance requirements beyond sensitivity such as specificity, stability, and ease of operation are critical. These performance requirements are governed by the properties of the photoactive materials and signal transduction mechanisms that are used in PEC biosensing. In this review, we categorize PEC biosensors into five areas based on their signal transduction strategy: (a) introduction of photoactive species, (b) generation of electron/hole donors, (c) use of steric hinderance, (d) in situ induction of light, and (e) resonance energy transfer. We discuss the combination of strengths and weaknesses that these signal transduction systems and their material building blocks offer by reviewing the recent progress in this area. Developing the appropriate PEC biosensor starts with defining the application case followed by choosing the materials and signal transduction strategies that meet the application-based specifications.
Highlights
Biosensors are devices that are used for analyzing biologically-relevant species using specific biorecognition elements and transducers (Soleymani and Li, 2017)
Polyethylenimine reduces the electron transport energy barrier of TiO2 mesocrystals by reducing the work function and thereby increasing the generated photocurrent. This type of performance enhancement was seen in reduced graphene oxide (RGO)/cadmium sulfide (CdS)/ZnS photoelectrode, where a widened light absorption range, spatial separation of photogenerated electronhole pairs, accelerated electron transfer, and reduction of surface defects resulting from the coupling of ZnS and CdS was observed (Zhao et al, 2016)
Yes; photogenerated Yes; Carboxylated surface Shi et al, 2018b electrons transferred obtained via synthesis to the proton in procedure allows for easy solution at low pH immobilization of pDNA via value
Summary
Biosensors are devices that are used for analyzing biologically-relevant species using specific biorecognition elements and transducers (Soleymani and Li, 2017). The photoactive materials used in PEC biosensing are chosen based on their electronic and optical parameters (incident photon-to-current conversion efficiency (IPCE), carrier mobility, response time, energy levels, and absorption spectrum), size/structure, stability against photobleaching, and ability to functionalize and integrate into devices. Polyethylenimine reduces the electron transport energy barrier of TiO2 mesocrystals by reducing the work function and thereby increasing the generated photocurrent This type of performance enhancement was seen in reduced graphene oxide (RGO)/CdS/ZnS photoelectrode, where a widened light absorption range, spatial separation of photogenerated electronhole pairs, accelerated electron transfer, and reduction of surface defects resulting from the coupling of ZnS (wide bandgap, ∼3.8 eV) and CdS (narrow bandgap, ∼2.4 eV) was observed (Zhao et al, 2016). We discuss the recent biosensing reports categorized under these mechanisms
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