In recent years, researchers have successfully applied diatom biosilica to molecular detection platforms including Surface-Enhanced Raman Scattering (SERS) optofluidic sensors that are currently capable of detecting a variety of biological and chemical molecules at concentrations as low as 10⁻¹⁰ M. This study investigates the feasibility of an SERS device that couples the sensing and pumping capabilities of diatom biosilica thin films by determining flow rate limitations and stability. In this paper, we quantify the ability of porous diatom biosilica thin films to continuously pump deionized (DI) water from a reservoir via wicking flow by utilizing the strong capillary forces of the porous film coupled with evaporation. Our microfluidic device is comprised of a narrow horizontal reservoir fixed to a horizontal capillary whose end contacts a diatom biosilica film. Flow rates were controlled by altering the size and/or temperature of the biosilica porous film, determined by tracking the liquid meniscus displacement in the reservoir, and correlated with a modified laminar boundary-layer model. System stability was observed by tracking flow rates over the course of a given experiment, image analysis of the meniscus contacting the film, and a flow duration study. We found that for untreated DI water bubbles begin to form in the capillary tube at temperatures above 40 °C, but degassed water remains stable at temperatures of 90 °C and below. The pumping capabilities of the films ranged from 0.11 to 10.46 µL/min, matched theoretical predictions, demonstrated stable flow trends, and maintained flow for over 48 h.

近年来，研究人员已成功地将硅藻生物二氧化硅应用于分子检测平台，包括表面增强拉曼散射（SERS）光流体传感器，该传感器目前能够检测浓度低至10 ^-10的多种生物和化学分子M.这项研究调查了SERS设备的可行性，该设备通过确定流速限制和稳定性来耦合硅藻生物二氧化硅薄膜的传感和泵浦功能。在本文中，我们利用多孔膜的强大毛细作用力和蒸发作用，来量化多孔硅藻生物二氧化硅薄膜通过芯吸流从储层连续泵送去离子（DI）水的能力。我们的微流体装置由固定在水平毛细管上的狭窄水平容器组成，水平毛细管的末端与硅藻生物二氧化硅膜接触。通过改变生物二氧化硅多孔膜的大小和/或温度来控制流速，通过跟踪储液器中液体弯月面的位移来确定流速，并与改进的层流边界层模型相关联。通过跟踪给定实验过程中的流速，与膜接触的弯液面的图像分析以及流动持续时间研究，观察到系统稳定性。我们发现，未经处理的去离子水在高于40°C的温度下会开始在毛细管中形成气泡，但脱气水在90°C及以下的温度下仍保持稳定。薄膜的泵送能力范围为0.11至10.46 µL / min，符合理论预测，显示出稳定的流量趋势，并保持流量超过48小时。