Rajeev Gayathri, Cowin Allison J, Voelcker Nicolas H, Prieto Simon Beatriz
Future Industries Institute, University of South Australia, Mawson Lakes, SA, Australia.
Faculty of Science, Institute for Biomedical Materials and Devices, University of Technology, Sydney, NSW, Australia.
Front Chem. 2019 Jun 12;7:438. doi: 10.3389/fchem.2019.00438. eCollection 2019.
A novel pore blockage-based electrochemical immunosensor based on the combination of 100 nm-magnetic nanoparticles (MNPs), as signal enhancers, and 200 nm-pore diameter nanoporous anodic alumina (NAA) membranes, as sensing platform, is reported. A peptide conjugate mimicking flightless I (Flii), a wound healing biomarker, was chosen as target analyte. The sensing platform consists of an anti-Flii antibody (Ab1)-modified NAA membrane attached onto a gold electrode. Anti-KLH antibody (Ab2)-modified MNPs (MNP-Ab2) were used to selectively capture the Flii peptide conjugate in solution. Sensing was based on pore blockage of the Ab1-modified NAA membrane caused upon specific binding of the MNP-Ab2-analyte complex. The degree of pore blockage, and thus the concentration of the Flii peptide conjugate in the sample, was measured as a reduction in the oxidation current of a redox species ([Fe(CN)]) added in solution. We demonstrated that pore blockage is drastically enhanced by applying an external magnetic field at the membrane backside to facilitate access of the MNP-Ab2-analyte complex into the pores, and thus ensure its availability to bind to the Ab1-modified NAA membrane. Combining the pore blockage-based electrochemical magnetoimmunosensor with an externally applied magnetic field, a limit of detection (LOD) of 0.5 ng/ml of Flii peptide conjugate was achieved, while sensing in the absence of magnetic field could only attain a LOD of 1.2 μg/ml. The developed sensing strategy is envisaged as a powerful solution for the ultra-sensitive detection of an analyte of interest present in a complex matrix.
报道了一种基于新型孔堵塞的电化学免疫传感器，该传感器将作为信号增强剂的100纳米磁性纳米颗粒（MNPs）与作为传感平台的200纳米孔径的纳米多孔阳极氧化铝（NAA）膜相结合。选择一种模拟无翅蛋白I（Flii）（一种伤口愈合生物标志物）的肽偶联物作为目标分析物。传感平台由附着在金电极上的抗Flii抗体（Ab1）修饰的NAA膜组成。抗钥孔血蓝蛋白抗体（Ab2）修饰的MNPs（MNP-Ab2）用于选择性捕获溶液中的Flii肽偶联物。传感基于Ab1修饰的NAA膜在MNP-Ab2-分析物复合物特异性结合时发生的孔堵塞。通过测量添加到溶液中的氧化还原物质（[Fe(CN)]）氧化电流的降低来测定孔堵塞程度，进而测定样品中Flii肽偶联物的浓度。我们证明，通过在膜背面施加外部磁场来促进MNP-Ab2-分析物复合物进入孔中，从而确保其与Ab1修饰的NAA膜结合的可用性，可显著增强孔堵塞。将基于孔堵塞的电化学磁免疫传感器与外部施加的磁场相结合，实现了对Flii肽偶联物0.5纳克/毫升的检测限，而在没有磁场的情况下传感只能达到1.2微克/毫升的检测限。所开发的传感策略被设想为用于超灵敏检测复杂基质中存在的目标分析物的强大解决方案。
