Precise and sensitive bioanalysis has been the major and urgent pursuit in pathologic diagnosis, food safety, environment monitoring, and drug evaluation. Photoelectrochemical (PEC) bioanalysis, as one of the most promising detection technologies, has rapidly expanded within the field of analysis. However, most of reported PEC analysis approaches still suffer from weak external anti-interference ability, high background, and the risk of false positive or negative errors due to their inherent single-signal readout. To overcome these shortcomings, new PEC-coupled dual-modal analysis approaches have been developed, where a dual-response signal can be derived through two completely different mechanisms and independent signal transduction pathways. This review introduces the basic principles of PEC biosensing and enumerates and classifies the substrate or probe selections, constructions, and applications of PEC-coupled dual-modal biosensors. Furthermore, the challenges and developmental prospects of PEC-coupled dual-mode sensing technologies are evaluated and discussed. We hope that this review will provide valuable insights into the latest advancements and practical applications of dual-mode PEC bioanalysis, which will be of great interest to those seeking to stay informed in this field.

The booming development of wearable devices has aroused increasing interests in flexible and stretchable devices. With mechanosensory functionality, these devices are highly desirable on account of their wide range of applications in electronic skin, personal healthcare, human–machine interfaces and beyond. However, they are mostly limited by single electrical signal feedback, restricting their diverse applications in visualized mechanical sensing. Inspired by the mechanochromism of structural color materials, interactively stretchable electronics with optical and electrical dual-signal feedbacks are recently emerged as novel sensory platforms, by combining both of their sensing mechanisms and characteristics. Herein, recent studies on interactively stretchable electronics based on structural color materials are reviewed. Following a brief introduction of their basic components (i.e., stretchable electronics and mechanochromic structural color materials), two types of interactively stretchable electronics with respect to the nanostructures of mechanochromic materials are outlined, focusing primarily on their design considerations and fabrication strategies. Finally, the main challenges and future perspectives of these emerging devices are discussed.

Localized surface plasmon resonance (LSPR) has been widely used in medical detection because of its time effectiveness, non-invasiveness, high sensitivity, and relatively simple fabrication process. Porous anodic alumina (PAA) can be regarded as a plasma substrate for label-free detection due to its unique two-dimensional structure. In this work, a vivid Au-PAA composite film with the inverted taper structure was developed by multi-step anodic oxidation and pore-widening processes followed by magnetron sputtering with Au nanoparticles (AuNPs). The highly saturated and bright structural color was generated by the synergistic effect of photonic and plasmonic modes. Interestingly, various Au-PAA composite films with structural colors altering from purple to red were obtained via adjusting the height/diameter ratio of PAA. Benefiting from the inverted taper structure, light trap characteristics were effectively enhanced by increasing the incident light and reducing the diffuse light. In addition, a finite difference time domain (FDTD) model was proposed to predict the relationship between the reflectance peak and the height of the composite film, and the simulated data were in good agreement with the experimental results. As a proof of concept, label-free detections of various reagents (water, ethanol, glycol, glycerol, and glucose), the concentration of glucose (refractive index sensitivity of 376 nm/RIU, RIU: refractive index unit), and thrombin (detection limit of 0.1 × 10⁻⁷ mol/L) were realized by the Au-PAA composite film. This vivid Au-PAA composite film provides a very powerful tool for in-situ label-free bio-detection.