CdSe-Co 3 O 4 @TiO 2 nanoflower–based photoelectrochemical platform probing visible light–driven virus detection

The design and construction of a visible light–driven photoelectrochemical (PEC) device is described based on a CdSe-Co 3 O 4 @TiO 2 nanoflower (NF). Moreover, an application to the ultrasensitive detection of viruses, such as hepatitis E virus (HEV), HEV-like particles (HEV-LPs), and SARS-CoV-2 spike protein in complicated lysate solution, is demonstrated. The photocurrent response output of a PEC device based on CdSe-Co 3 O 4 @TiO 2 is enhanced compared with the individual components, TiO 2 and CdSe-Co 3 O 4 . This can be attributed to the CdSe quantum dot (QD) sensitization effect and strong visible light absorption to improve overall system stability. A robust oxygen-evolving catalyst (Co 3 O 4 ) coupled at the hole-trapping site (CdSe) extends the interfacial carrier lifetime, and the energy conversion efficiency was improved. The effective hybridization between the antibody and virus resulted in a linear relationship between the change in photocurrent density and the HEV-LP concentration ranging from 10 fg mL –1 to 10 ng mL –1 , with a detection limit of 3.5 fg mL –1 . This CdSe-Co 3 O 4 @TiO 2 -based PEC device achieved considerable sensitivity, good specificity, and acceptable stability and demonstrated a significant ability to develop an upgraded device with affordable and portable biosensing capabilities. Graphical Abstract