Institute of Biological Information Processing, Bioelectronics (IBI-3), Forschungszentrum Jülich GmbH, Jülich, Germany; Laboratory for Biomaterials, Institute for Biotechnology and Helmholtz-Institute for Biomedical Engineering, RWTH Aachen University, Aachen, Germany.
Institute of Biological Information Processing, Bioelectronics (IBI-3), Forschungszentrum Jülich GmbH, Jülich, Germany.
Bioelectrochemistry. 2020 Dec;136:107589. doi: 10.1016/j.bioelechem.2020.107589. Epub 2020 Jul 3.
Better approaches are critically needed for in situ point-of-care diagnostic biosensors that enable primary care physicians, or even individual patients, to directly analyze biological fluids without complicated sample pretreatments. Additional purification steps consume time, consume reagents, often require other equipment, and can introduce false-negative results. Biosensors have been modified with blocking molecules to reduce biofouling; however, the effectiveness relies on their chemical composition and morphology. Here, we used a polyethylene glycol film to suppress unspecific binding from human serum on an electrochemical malaria aptasensor. A detailed study of the variation of the chemical and morphological composition of the aptamer/polyethylene glycol mixed monolayer as a function of incubation time was conducted. Higher resistance to matrix biofouling was found for polyethylene glycol than for hydrophobic alkanethiol films. The best sensor performance was observed for intermediate polyethylene glycol immobilization times. With prolonged incubation, phase separation of aptamer, and polyethylene glycol molecules locally increased the aptamer density and thereby diminished the analyte binding capability. Remarkably, polyethylene glycols do not affect the aptasensor sensitivity but enhance the complex matrix tolerance, the dynamic range, and the limit of detection. Careful tuning of the blocking molecule immobilization is crucial to achieving high aptasensor performance and biofouling resistance.
迫切需要更好的方法来实现原位即时诊断生物传感器，使初级保健医生甚至个体患者能够直接分析生物体液，而无需复杂的样品预处理。额外的纯化步骤既耗时又耗试剂，通常还需要其他设备，并且可能导致假阴性结果。已经有研究通过将阻断分子修饰生物传感器来减少生物污垢；然而，其有效性取决于它们的化学组成和形态。在这里，我们使用聚乙二醇薄膜来抑制电化学疟疾适体传感器上人血清的非特异性结合。我们详细研究了适体/聚乙二醇混合单层的化学和形态组成随孵育时间的变化。与疏水性烷硫醇薄膜相比，聚乙二醇对基质生物污垢的抵抗力更高。对于中间的聚乙二醇固定化时间，传感器表现出最佳性能。随着孵育时间的延长，适体和聚乙二醇分子的相分离会局部增加适体密度，从而降低分析物的结合能力。值得注意的是，聚乙二醇不会影响适体传感器的灵敏度，反而会增强复杂基质的耐受性、动态范围和检测限。仔细调整阻断分子的固定化对于实现高适体传感器性能和抗生物污垢至关重要。
