Electroanalytical Chemistry Research Laboratory, Department of Analytical Chemistry, Faculty of Chemistry, University of Mazandaran, Babolsar, Iran; Department of Chemical Industry, Faculty of Alzahra, Bushehr Branch, Technical and Vocational University (TVU), Bushehr, Iran.
Electroanalytical Chemistry Research Laboratory, Department of Analytical Chemistry, Faculty of Chemistry, University of Mazandaran, Babolsar, Iran.
J Pharm Biomed Anal. 2019 Jan 30;163:180-187. doi: 10.1016/j.jpba.2018.10.006. Epub 2018 Oct 3.
In this paper, we report the application of a reusable electrochemical aptasensor for detection of tryptophan by using Fe(bpy) as an electroactive indicator and based on the target-compelled aptamer displacement. The aptasensor fabricated by self-assembling the thiolated probe on the surface of graphite screen-printed electrode modified with gold nanoparticles/multiwalled carbon nanotubes and chitosan nanocomposite (AuNPs/MWCNTs-Chit/SPE). Afterward, Trp aptamer (Apt) immobilized on the modified electrode surface through hybridization. In the absence of Trp, a sharp peak of [Fe(bpy)](p-CHCH SO) can be observed in differential pulse voltammetry (DPV) study. The introduction of Trp led to the formation of aptamer-Trp complex and dissociation of the aptamer from the DNA-Apt duplex on the electrode surface into the solution and decreases the peak current intensity of electroactive indicator. This is because, Fe(bpy) tends to bind to the two strands DNA. Therefore, the peak current of [Fe(bpy)](p-CHCH SO) linearly decreased with increasing the concentration of Trp over a range of 3.0 nM- 100 μM. The detection limit (3 σ) was 1.0 nM. In addition, we examined the selectivity of the constructed biosensor for tyrosine, histidine, arginine, lysine, valine and methionine that belonged to the amino acid family. The obtained results showed that the fabricated sensor had a good selectivity for Trp against the other examined amino acids. Also, the potential applicability of the aptasensor was investigated by detecting the Trp in a complex media such as human blood plasma spiked with Trp.
本文报告了一种可重复使用的电化学适体传感器在检测色氨酸方面的应用，该传感器以Fe(bpy)为电活性指示剂，基于目标诱导的适体置换。该适体传感器是通过将巯基探针自组装到修饰有金纳米粒子/多壁碳纳米管和壳聚糖纳米复合材料(AuNPs/MWCNTs-Chit/SPE)的石墨丝网印刷电极表面上制备而成。随后，Trp 适体(Apt)通过杂交固定在修饰电极表面上。在没有 Trp 的情况下，在差分脉冲伏安法(DPV)研究中可以观察到Fe(bpy)的尖锐峰。Trp 的引入导致适体-Trp 复合物的形成，以及适体从电极表面的 DNA-Apt 双链体解离到溶液中，从而降低电活性指示剂的峰电流强度。这是因为Fe(bpy)倾向于与两条 DNA 链结合。因此，Fe(bpy)的峰电流随着 Trp 浓度在 3.0 nM-100 μM 范围内的增加而线性降低。检测限(3σ)为 1.0 nM。此外，我们研究了构建的生物传感器对酪氨酸、组氨酸、精氨酸、赖氨酸、缬氨酸和甲硫氨酸等属于氨基酸家族的物质的选择性。所得结果表明，该传感器对 Trp 具有良好的选择性，而对其他检测到的氨基酸则没有。此外，还通过检测人血浆中添加 Trp 的复杂介质中的 Trp，研究了适体传感器的潜在适用性。
