快速电荷载流子复合和低导电率对于设计高效光电化学（PEC）传感器至关重要。在此，我们提出了少层MXene（Ti3C2Tx）的部分氧化来构建用于PEC检测叶酸受体（FR），特别是FR表达的乳腺癌细胞（MDA-MB-231）的光活性TiO2 / Ti3C2Tx平台。 MXene-Ti3C2Tx分散在自然开放的空气条件下氧化，连续暴露六（06）天，允许TiO2在MXene纳米片上均匀原位生长（MX-06）。这种暴露使MXene片部分氧化，并具有平衡的TiO2和MXene含量，可以表现出改进的光响应特性，这归因于氧化还原活性的TiO2和高导电性的基础Ti3C2Tx之间的协同作用。然后，通过连接壳聚糖和叶酸（FA）网络，将光电极适应于生物识别，这使得选择性检测FR表达的细胞具有显着的抗生物污染能力，如牛血清白蛋白（BSA），血红蛋白和免疫球蛋白G（Ig G）。检测机制依赖于FA与癌细胞叶酸受体的强亲和力，该亲和力成比例地抑制了光电极对抗坏血酸（AA）（介质）的PEC氧化反应。提出的抑制策略使FR表达的MDA-MB-231细胞在1×102至2×107 细胞/毫升的浓度范围内进行灵敏检测，检测限为1.01个细胞/毫升（S/N = 3）。 版权所有© 2023 Elsevier B.V.

The rapid-charge carrier recombination and low conductivity are critical in devising an efficient photoelectrochemical (PEC) sensor. Herein, we propose partial oxidation of few-layered MXene (Ti3C2Tx) to construct a photo-active TiO2/Ti3C2Tx platform that could be configured for PEC sensing of folate receptors (FR), particularly, FR-expressing breast cancer cells (MDA-MB-231). MXene-Ti3C2Tx dispersion was oxidized in natural-open air conditions, where continuous exposure for six (06) days allowed for homogeneous in-situ growth of TiO2 over MXenes nanosheets (MX-06). This exposure enabled partial oxidation of MXene-sheets with a balanced TiO2 to MXene content that could exhibit improved photoresponsive characteristics owing to the synergism of redox-active TiO2 and highly conductive underlying Ti3C2Tx. The photoelectrode was then adapted for biorecognition by conjugating chitosan and folic acid (FA) networks, which permitted selective detection of FR-expressed cells with significant antifouling capabilities against common proteins such as bovine serum album (BSA), hemoglobin, and immunoglobulin G. (Ig G). The detection mechanism relies on FA's strong affinity for cancer cell folate receptors, which proportionally inhibited the photoelectrodes PEC oxidation response to ascorbic acid (AA)(mediator). The proposed inhibition strategy enabled sensitive detection of FR-expressed MDA-MB-231 cells in the concentration range of 1 × 102 to 2 × 107 cells/mL with a detection limit of 1.01 cells/mL (S/N = 3).Copyright © 2023 Elsevier B.V. All rights reserved.