Institute of Sensor and Actuator Systems, TU Wien, Gusshausstrasse 27⁻29, 1040 Vienna, Austria.
BioSense Institute, Dr Zorana Đinđića 1, 21000 Novi Sad, Serbia.
Sensors (Basel). 2018 Jul 12;18(7):2250. doi: 10.3390/s18072250.
Bacterial contamination of water sources (e.g., lakes, rivers and springs) from waterborne bacteria is a crucial water safety issue and its prevention is of the utmost significance since it threatens the health and well-being of wildlife, livestock, and human populations and can lead to serious illness and even death. Rapid and multiplexed measurement of such waterborne pathogens is vital and the challenge is to instantly detect in these liquid samples different types of pathogens with high sensitivity and specificity. In this work, we propose a biosensing system in which the bacteria are labelled with streptavidin coated magnetic markers (MPs-magnetic particles) forming compounds (MLBs-magnetically labelled bacteria). Video microscopy in combination with a particle tracking software are used for their detection and quantification. When the liquid containing the MLBs is introduced into the developed, microfluidic platform, the MLBs are accelerated towards the outlet by means of a magnetic field gradient generated by integrated microconductors, which are sequentially switched ON and OFF by a microcontroller. The velocities of the MLBs and that of reference MPs, suspended in the same liquid in a parallel reference microfluidic channel, are calculated and compared in real time by a digital camera mounted on a conventional optical microscope in combination with a particle trajectory tracking software. The MLBs will be slower than the reference MPs due to the enhanced Stokes' drag force exerted on them, resulting from their greater volume and altered hydrodynamic shape. The results of the investigation showed that the parameters obtained from this method emerged as reliable predictors for concentrations.
水源（例如湖泊、河流和泉水）中的细菌污染是一个至关重要的水安全问题，其预防至关重要，因为它威胁到野生动物、牲畜和人类的健康和福祉，并可能导致严重疾病甚至死亡。快速和多重测量这些水源性病原体至关重要，挑战在于即时检测这些液体样本中不同类型的病原体，具有高灵敏度和特异性。在这项工作中，我们提出了一种生物传感系统，其中细菌用链霉亲和素包被的磁性标记物（MPs-磁性颗粒）标记，形成化合物（MLBs-磁性标记细菌）。视频显微镜结合粒子跟踪软件用于它们的检测和定量。当含有 MLBs 的液体被引入开发的微流控平台时，MLBs 通过集成微导体产生的磁场梯度加速向出口移动，微导体通过微控制器顺序开启和关闭。MLBs 的速度和悬浮在同一液体中的参考 MPs 的速度在实时由安装在常规光学显微镜上的数字相机与粒子轨迹跟踪软件相结合来计算和比较。MLBs 的速度将比参考 MPs 慢，因为它们的体积更大且流体力形状发生改变，导致增强的斯托克斯阻力对它们施加的影响。研究结果表明，该方法获得的参数可作为浓度的可靠预测因子。
