Abstract：
The degree of the carbohydrate antigen 125 (CA-125) level in serum is positively correlated with the severity of ovarian cancer. In this study, a facile photoelectrochemical (PEC) immunoassay was devised for sensitive detection of CA-125 employing enzyme-catalyzed precipitation to weaken the photocurrent of hollow porous In2O3 nanotubes incorporating CdS nanoparticles. Upon the addition of the target analyte, horseradish peroxidase (HRP) enriches as a result of the formation of the sandwich immunocomplex, which can catalyze the conversion of 4-chloro1-naphthol (4-CN) to benzo-4-chlorohexadienone (4-CD) employing H2O2 as a cofactor. The as-produced insoluble precipitate acts as an obstacle to hinder the absorption of visible light by photoactive materials, thereby resulting in a decrease in photocurrent. Moreover, the weakened signal can be easily read out by a digital multimeter (DMM), advancing the convenience of the detection system. The preliminary analysis data indicate that the PEC immunoassay shows an efficient response to CA-125 levels ranging from 0.1 to 100 U mL-1 with a limit of detection (LOD) as low as 0.046 U mL-1 (S/N = 3). Most importantly, the proposed portable method has shown satisfactory performance in terms of selectivity, reproducibility, stability, and analysis in complex biological matrices.
摘要：
血清糖类抗原125(CA-125)水平与卵巢癌严重程度呈正相关。在这项研究中,设计了一种简便的光电化学（PEC）免疫测定法，用于灵敏检测CA-125，采用酶催化沉淀来削弱掺入CdS纳米粒子的中空多孔In2O3纳米管的光电流。添加目标分析物后，辣根过氧化物酶（HRP）由于夹心免疫复合物的形成而富集，可以使用H2O2作为辅因子催化4-氯1-萘酚（4-CN）转化为苯并-4-氯己二烯酮（4-CD）。产生的不溶性沉淀物作为阻碍光活性材料吸收可见光的障碍，从而导致光电流的减少。此外，减弱的信号可以很容易地读出数字万用表（DMM），提高了检测系统的便利性。初步分析数据表明，PEC免疫测定对CA-125水平的有效反应范围为0.1至100UmL-1，检测限（LOD）低至0.046UmL-1（S/N=3）。最重要的是,所提出的便携式方法在选择性方面表现出令人满意的性能，再现性，稳定性,并在复杂的生物基质中进行分析。
