Novel Photoelectrochemical Biosensing Platform Based on a Double Type II CdLa₂S₄/SnIn₄S₈/Sb₂S₃ Ternary Heterojunction as Photoactive Materials and NiCo₂O₄ Nanospheres as a Photoquencher for CA19-9 Detection

Abstract

A novel signal-off biosensing platform based on the CdLa2S4/SnIn4S8/Sb2S3 heterojunction as photoactive materials and NiCo2O4 nanospheres as a photoquencher was developed to achieve the sensitive detection of CA19-9. First, the narrow band gap hydrangea-like CdLa2S4/SnIn4S8/Sb2S3 not only provided excellent photocurrent response but also supplied a mass of active sites that facilitated the loading of capture antibody (Ab1). Second, a double type II CdLa2S4/SnIn4S8/Sb2S3 heterojunction promoted the fast separation and migration of photogenerated e–/h+ and overcame the problem of short carrier lifetime caused by the recombination of photogenerated carriers. In addition, to improve the sensitivity of the constructed sensor to detect CA19-9, signal tags (p-type NiCo2O4) with large steric hindrance were introduced to accomplish signal amplification by the effect of double signal quenching. On one hand, NiCo2O4, which was strongly responsive to visible light, utilized its own advantages to compete for AA with CdLa2S4/SnIn4S8/Sb2S3, resulting in a decrease in the hole scavenging rate of the substrate. On the other hand, the photoquencher NiCo2O4 also prevented AA from contacting the matrix and further aggravated the photoelectrochemical (PEC) signal-damping effect. The PEC immunosensor was prepared with brilliant selectivity and splendid stability to detect CA19-9 (0.001–50 U/mL), and the detection limit was 0.0004 U/mL (S/N = 3).

An ultrasensitive photoelectrochemical assay for tumor necrosis factor-alpha based on hollow CdS cubes as a signal generator and NiCo2O4-Au as a signal extinguisher

“…3D shows the presence of Au (84.0 and 87.7 eV). 44 These results confirm that NiCo 2 O 4 -Au has been synthesized successfully.…”

Portable self-powered photoelectrochemical immunosensor based on Cu3SnS4 nanoflower for ultra-sensitive and real-time detection of human cytochrome c

“…Alternatively, photoelectrochemical (PEC) immunosensors have attracted significant attention and are widely applied in the analysis and detection technological fields owing to their fantastic advantages, including fast response, high sensitivity, and high specificity. 20,21 PEC immunosensors can effectively reduce the interference of background signal by separating the excitation signal (light) and response signal (current), leading to ultra-high sensitivity and excellent stability. 22,23 For example, Wang et al fabricated a CdS/CuInS 2 /Au/TiO 2 nanotube array photoelectric sensor with immobilized aptamers on the electrode surface for the sensitive detection of Cyt c. 24 Moreover, photoactive materials with high photoelectric conversion efficiency are crucial in the application of PEC immunosensors, which can significantly improve the sensitivity in PEC detection fields.…”