μ-'Diving suit' for liquid-phase high-Q resonant detection
μ-'Diving suit' for liquid-phase high-Q resonant detection
复制标题
mu-用于液相高 Q 共振检测的“潜水服”
DOI：
10.1039/c5lc01187f
复制
发表时间：
2016-01-01
期刊：
影响因子：
6.1
通讯作者：
Li, Xinxin
中科院分区：
文献类型：
--
作者：
Yu, Haitao;Chen, Ying;Li, Xinxin
共振悬臂梁传感器首次穿上防水“潜水服”，用于液体中的实时生物/化学检测。mu-“潜水服”技术不仅可以有效避免由于重液体阻尼而产生的不可持续的共振，还可以避免悬臂体上不可避免的非特异性吸附。这种新技术确保了悬臂梁在溶液环境中的长时间高Q谐振，用于实时痕量浓度生物/化学检测和分析。在形成集成谐振微悬臂梁之后，在悬臂梁的顶部依次形成图案化的光刻胶和疏水聚对二甲苯薄膜，分别作为牺牲层和防水涂层。在牺牲层释放之后，在聚对二甲苯涂层和悬臂梁之间形成空气间隙，以保护谐振悬臂梁免受重液体阻尼效应的影响。只有一个小的传感池区域，位于悬臂的自由端和局部涂覆有特定的传感材料，暴露于液体分析物的重量检测。通过记录频移信号，可以实时检测特异性吸附的分析物质量。为了保证悬臂梁的振动运动，同时防止传感池区域的液体泄漏，在传感池周围设计了一种疏水聚对二甲苯窄缝结构。对狭缝的防泄漏效应和阻尼限制谐振Q值进行了建模和优化设计。该悬臂梁集成了电热共振激励和压阻式频率读出技术，嵌入微流控芯片中，构成了用于液相生物/化学检测的实验室芯片微系统。实验结果表明，在水中的Q值为23，液相连续工作时间大于20小时。两种传感芯片在传感池中分别装载两种传感材料，成功地实现了对ppb级有机磷农药乙酰甲胺磷和大肠杆菌的实时液相检测。coli DH 5 α的PBS溶液中。提出的方法从根本上解决了长期存在的问题，无法在液体中运行的谐振微传感器。
A resonant cantilever sensor is, for the first time, dressed in a water-proof 'diving suit' for real-time bio/chemical detection in liquid. The mu-'diving suit' technology can effectively avoid not only unsustainable resonance due to heavy liquid-damping, but also inevitable nonspecific adsorption on the cantilever body. Such a novel technology ensures long-time high-Q resonance of the cantilever in solution environment for real-time trace-concentration bio/chemical detection and analysis. After the formation of the integrated resonant micro-cantilever, a patterned photoresist and hydrophobic parylene thin-film are sequentially formed on top of the cantilever as sacrificial layer and water-proof coat, respectively. After sacrificial-layer release, an air gap is formed between the parylene coat and the cantilever to protect the resonant cantilever from heavy liquid damping effect. Only a small sensing-pool area, located at the cantilever free-end and locally coated with specific sensing-material, is exposed to the liquid analyte for gravimetric detection. The specifically adsorbed analyte mass can be real-time detected by recording the frequency-shift signal. In order to secure vibration movement of the cantilever and, simultaneously, reject liquid leakage from the sensing-pool region, a hydrophobic parylene made narrow slit structure is designed surrounding the sensing-pool. The anti-leakage effect of the narrow slit and damping limited resonance Q-factor are modelled and optimally designed. Integrated with electro-thermal resonance excitation and piezoresistive frequency readout, the cantilever is embedded in a micro-fluidic chip to form a lab-chip micro-system for liquid-phase bio/chemical detection. Experimental results show the Q-factor of 23 in water and longer than 20 hours liquid-phase continuous working time. Loaded with two kinds of sensing-materials at the sensing-pools, two types of sensing chips successfully show real-time liquid-phase detection to ppb-level organophosphorous pesticide of acephate and E. coli DH5 alpha in PBS, respectively. The proposed method fundamentally solves the long-standing problem of being unable to operate a resonant micro-sensor in liquid well.