Roach Paul, Atherton Shaun, Doy Nicola, McHale Glen, Newton Michael I
School of Science and Technology, Nottingham Trent University, Clifton Campus, Nottingham. NG11 8NS. UK.
Sensors (Basel). 2007 Nov 1;7(11):2539-2547. doi: 10.3390/s71102539.
SU-8 is a technologically important photoresist used extensively for thefabrication of microfluidics and MEMS, allowing high aspect ratio structures to beproduced. In this work we report the use of SU-8 as a Love wave sensor guiding layerwhich allows the possibility of integrating a guiding layer with flow cell during fabrication.Devices were fabricated on ST-cut quartz substrates with a single-single finger design suchthat a surface skimming bulk wave (SSBW) at 97.4 MHz was excited. SU-8 polymer layerswere successively built up by spin coating and spectra recorded at each stage; showing afrequency decrease with increasing guiding layer thickness. The insertion loss andfrequency dependence as a function of guiding layer thickness was investigated over thefirst Love wave mode. Mass loading sensitivity of the resultant Love wave devices wasinvestigated by deposition of multiple gold layers. Liquid sensing using these devices wasalso demonstrated; water-glycerol mixtures were used to demonstrate sensing of density-viscosity and the physical adsorption and removal of protein was also assessed usingalbumin and fibrinogen as model proteins.
SU-8是一种在技术上很重要的光刻胶，广泛用于微流体和微机电系统的制造，能够制造出高纵横比的结构。在这项工作中，我们报告了将SU-8用作洛夫波传感器的波导层，这使得在制造过程中能够将波导层与流通池集成在一起。器件在ST切割石英衬底上采用单指设计制造，从而激发97.4 MHz的表面掠射体波（SSBW）。通过旋涂依次沉积SU-8聚合物层，并在每个阶段记录光谱；结果表明，随着波导层厚度的增加，频率降低。在基模洛夫波上研究了插入损耗和频率随波导层厚度的变化关系。通过沉积多层金来研究所得洛夫波器件的质量负载灵敏度。还展示了使用这些器件进行液体传感；用水 - 甘油混合物来展示对密度 - 粘度的传感，并且还使用白蛋白和纤维蛋白原作为模型蛋白评估了蛋白质的物理吸附和去除情况。
