Soomro Razium Ali, Jawaid Sana, Kalawar Nazar Hussain, Tunesi Mawada, Karakuş Selcan, Kilislioğlu Ayben, Willander Magnus
Beijing Advanced Innovation Centre for Soft Matter Science and Engineering, Beijing University of Chemical Technology, Beijing, 100029, PR China.
State Key Laboratory of Chemical Resource Engineering, School of Chemistry, Beijing University of Chemical Technology, Beijing, 100029, PR China.
Biosens Bioelectron. 2020 Oct 15;166:112439. doi: 10.1016/j.bios.2020.112439. Epub 2020 Jul 22.
Interfacial charge-carrier recombination is a bottle-neck issue restricting photoelectrochemical biosensors advancement in the wearable clinical electronics. In this study, we propose a simple approach to construct a highly efficient photoactive heterojunction capable of functioning as an active substrate in PEC biosensing of CD44 proteins. Taking the advantage of high photocatalytic activity of BiVO, and biocompatible yet conductive 2D-TiCT nanosheets, a workable heterojunction was constructed between in-situ formed TiO from the partially oxidized TiCT and lysine functionalized BiVO (TiO/MX-BiVO). The interfacial arrangement was ideal for promoting fast charge transfer from photo-excited BiVO and TiO to TiCT, constructing an energy level-cascade that permits minimal charge-carrier recombination besides robust photocatalytic redox activity. The PEC biosensor relies on the ligand-protein interaction, where hyaluronic acid was directly immobilized over TiO/MX-BiVO based on the interactions between carboxyl of lysine and amino moieties of hyaluronic acid. The PEC biosensor response depends on the inhibition in the measured photo-oxidation current of mediator species, i.e., ascorbic acid after the addition of CD44 proteins. The superior photo-activity, and robust heterojunction arrangement, produced a sensitive signal capable of recognizing CD44 in the wide concentration window of 2.2 × 10 ng mL to 3.2 ng mL with a low-detection limit of 1.4 × 10 pg mL. The strong interaction between lysine functionalized BiVO and hyaluronic acid enabled biosensor to exhibit robust antifouling characteristics towards similar proteins such as PSA and NSE. The quantification of CD44 protein from real-blood serum samples further confirmed the biosensor's reliability for clinical application.
界面电荷载流子复合是限制可穿戴临床电子设备中光电化学生物传感器发展的瓶颈问题。在本研究中，我们提出了一种简单的方法来构建一种高效的光活性异质结，该异质结能够在CD44蛋白的光电化学（PEC）生物传感中作为活性底物发挥作用。利用BiVO₄的高光催化活性以及具有生物相容性且导电的二维Ti₃C₂Tₓ纳米片，在由部分氧化的Ti₃C₂Tₓ原位形成的TiO₂与赖氨酸功能化的BiVO₄（TiO₂/MX-BiVO）之间构建了一个可行的异质结。这种界面排列非常有利于促进光激发的BiVO₄和TiO₂中的电荷快速转移到Ti₃C₂Tₓ，构建一个能级级联，除了具有强大的光催化氧化还原活性外，还能使电荷载流子复合最少。该PEC生物传感器依赖于配体-蛋白质相互作用，其中基于赖氨酸的羧基与透明质酸的氨基部分之间的相互作用，将透明质酸直接固定在TiO₂/MX-BiVO上。该PEC生物传感器的响应取决于添加CD44蛋白后对介体物质（即抗坏血酸）测量的光氧化电流的抑制。优异的光活性和强大的异质结排列产生了一个灵敏的信号，能够在2.2×10⁻⁹ ng mL⁻¹至3.2 ng mL⁻¹的宽浓度窗口中识别CD44，检测下限低至1.4×10⁻¹² pg mL⁻¹。赖氨酸功能化的BiVO₄与透明质酸之间的强相互作用使生物传感器对前列腺特异性抗原（PSA）和神经元特异性烯醇化酶（NSE）等相似蛋白质表现出强大的抗污特性。从实际血清样本中对CD44蛋白的定量进一步证实了该生物传感器在临床应用中的可靠性。
