Label-free attomolar protein detection using a MEMS optical interferometric surface-stress immunosensor with a freestanding PMMA/parylene-C nanosheet
Label-free attomolar protein detection using a MEMS optical interferometric surface-stress immunosensor with a freestanding PMMA/parylene-C nanosheet
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DOI：
10.1016/j.bios.2020.112778
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发表时间：
2021-01-15
影响因子：
12.6
通讯作者：
Takahashi, Kazuhiro
中科院分区：
文献类型：
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作者：
Choi, Yong-Joon;Takahashi, Toshiaki;Takahashi, Kazuhiro
我们展示了一种基于光学干涉仪的表面应力免疫传感器，它使用独立的聚甲基丙烯酸甲酯(PMMA)/对苯二甲酸甲酯(PMMA)纳米片，具有高灵敏度，用于检测生物分子。将聚甲基丙烯酸甲酯/对苯二甲酸乙二醇酯纳米片转移到具有微腔结构的硅衬底上，制备了具有密封腔结构的亚微米厚自支撑膜。通过卷尺试验测得转移后的对二甲苯-C与粘结剂对二甲苯-C层之间的粘附力为1.06-2.4N/10 mm。避免了德拜屏蔽，这些纳米机械传感器可以通过电荷传递的表面应力的变化来检测膜表面的吸附。我们对受体密度和固定化方式进行了优化，以获得高灵敏度。为了评价传感器的选择性，测量了不同蛋白质引起的膜偏转，光谱漂移表明只对靶抗原具有高的选择性。该传感器对人血清白蛋白抗原的最低检出限为0.1~1fg/mL(1.5~15am)，比传统的微悬臂梁传感器低2万倍。
We demonstrated an optical interferometer-based surface-stress immunosensor using freestanding polymethyl methacrylate (PMMA)/parylene-C nanosheet with high sensitivity for detection of biomolecules. PMMA/parylene-C nanosheets were transferred onto a silicon substrate with microcavities to fabricate freestanding submicron-thick membrane with a sealed cavity structure. The adhesive force between the transferred parylene-C and binder parylene-C layer was measured to be 1.06-2.4 N/10 mm by tape test. Evading Debye shielding, these nanomechanical sensors allow detection of the adsorption on the membrane surface through changes in surface stress transduced by the electric charge. We optimized the density of receptors and mode of immobilization for high sensitivity. To evaluate the selectivity of the sensor, membrane deflections induced by various proteins were measured and the spectral shifts showed high selectivity only for the target antigen. The minimum limit of detection (LOD) of the sensor for human serum albumin antigen was 0.1-1 fg/mL (1.5-15 aM), which was 20,000 times lower than that of the conventional micro-cantilever sensor.