Affinity-Based Detection of Biomolecules Using Photo-Electrochemical Readout

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.

Surface modification of TiO2 for photoelectrochemical DNA biosensors

“…It is evident from this investigation that the TiO 2 modification with CA is the basis for high‐performance signal‐off PEC DNA biosensors with a high dynamic range and low LOD. Some recent examples in literature (Victorious, Saha, Pandey, Didar, & Soleymani, 2019) of PEC DNA biosensors are as follows: CdS/MoS 2 heterojunction‐based electode (LOD = 0.39 fM, linear range = 1 fM–100 pM) (Zang, Lei, Hao, & Ju, 2016), CdS/Ag NP electrodes (LOD = 0.2 fM, linear range = 1 fM–100 pM) (Zhang et al, 2016) and Au NP‐modified TiO 2‐x electrodes (LOD = 0.6 pM, linear range = 100 nM) (Shu, Qiu, Lv, Zhang, & Tang, 2018). The main advantage our system offers is its ease of fabrication and operation due to the ease of surface modification of TiO 2 with caffeic acid.…”

Electrochemical sensing of blood proteins for mild traumatic brain injury (mTBI) diagnostics and prognostics: towards a point-of-care application

“…The PEC sensor performance relies on photoactive materials that produce photocurrent upon absorbing photons and engage in redox reaction at the WE surface via different transduction mechanisms: formation of electrons/holes, introduction of photoactive species, steric hindrance, in situ induction of light, or resonance energy transfer. 146,192,193 PEC-based (bio)sensing, although presenting a promising novel analytical method for biomarker detection, is yet at a very early stage for practical application. Nevertheless, a few examples of PEC sensing strategies have been suggested for detection of mTBI-related biomarkers such as MMP-2, 194,195 NFL,196 NSE,197 Tau proteins, 149,198 and CRP.…”

“… 146,199 Further discussion of PEC affinity-based detection principles, types of photoactive species and signal transduction mechanisms is outside the scope of this work and can be found e.g. in a recent detailed review by Victorious et al 193 …”

Enhancing the Sensitivity of Photoelectrochemical DNA Biosensing Using Plasmonic DNA Barcodes and Differential Signal Readout

“…Photoelectrochemical (PEC) biosensors have been heavily explored over the past decade due to their promise for improved signal‐to‐noise ratio and enhanced limit‐of‐detection [1–3] . These biosensors translate specific biorecognition events into a change in the output PEC signal [1, 4] .…”

“…Photoelectrochemical (PEC) biosensors have been heavily explored over the past decade due to their promise for improved signal‐to‐noise ratio and enhanced limit‐of‐detection [1–3] . These biosensors translate specific biorecognition events into a change in the output PEC signal [1, 4] . As with their electrochemical analogues, the limit‐of‐detection of PEC transducers is often compromised due to signal fluctuations caused by environmental interferents and minute variations in experimental conditions [5–7] .…”