A microfluidic platform for foodborne pathogenic bacteria detections

近年来食源性疾病的暴发导致食品安全检验机构和食品工业对快速、灵敏和高通量的食源性病原体检测方法和仪器的需求不断增长。一个低成本、强大、可靠和高通量的病原体检测平台可以满足这一日益增长的需求，并使食品安全部门能够快速应对食源性疾病爆发和食品供应链上的生物恐怖袭击等事件。为此，本研究计划开发一种灵敏、低成本的基于微流控药物的检测系统，该系统可以绕过培养增菌过程，在短时间内完成对现实世界中食品的全部检测。*拟议的计划集成了样品制备和芯片上的样品检测功能。它包括用于从均质的现实世界食品样本中去除大的食物颗粒的分离器，用于从样本中去除液体的浓缩器，以及用于有效捕获和检测目标细菌的检测器。因此，可以在系统内以这种连续流动的方式处理和随后分析输入样品。对于目前的Discovery Grant(DG)应用，主要目标是开发一种能够提供灵敏和快速检测的超灵敏微流控设备。为了实现这一点，我们建议用树状大分子和偶联的目标细菌特异性适配子对微流控通道壁进行表面修饰。这不仅将减少由于非特异性结合到微通道壁上的背景信号，而且还提供了多个反应位点来随后附着捕获适体的细菌。将推进研究，以研究具有不同连接长度的不同类型的接头到锚定表面的适配子。为了进一步增强检测，还将使用滚圆放大(RCA)信号增强，有效地增强检测信号。最后对微流控流型进行了研究，以提高检测效率。*工作的预期意义：拟议的检测系统是新颖的，因为它不仅提供快速和灵敏的检测，而且还有可能与其他微流控芯片上的功能集成，如分离器和浓缩器。拟议的研究是整个拟议的探测系统的关键组成部分。如果成功实施，全面整合的检测平台将大大减少检测时间和降低检测成本，从而使安全部门能够扩大其检测范围和频率，并在识别可能的污染物和可疑活动方面发挥更积极的作用。

Outbreaks of foodborne diseases in recent years have led to the growth in demand for rapid, sensitive, and high-throughput methods and instrumentation for foodborne pathogens from food safety inspection authorities and food industries. A low-cost, robust, reliable and high-throughput pathogen detection platform can meet this increasing demand and allow food safety authorities to quickly respond to events such as foodborne disease outbreaks and bioterrorist attacks on our food supply chains. To this end, this research program is to develop a sensitive and low cost microfludics-based detection system that can circumvent the need for culture enrichment process and complete the whole testing of real-world foods within a short period of time. ******The proposed program integrates sample preparation and sample detection on-chip functionalities. It includes a separator to remove large food particles from the homogenized real-world food sample, a concentrator to remove liquid from the sample, and a detector for efficient capture and detection of target bacteria. As such, an input sample can be processed and subsequently analyzed in this continuous flow fashion within the system. For the current Discovery Grant (DG) application, the main objective is to develop an ultra sensitive microfluidic device that offers both sensitive and rapid detections. To achieve this, we propose to surface modify the microfluidic channel walls with dendrimers and conjugate target bacteria-specific aptamers. This will not only reduce the background signals due to non-specific bindings to the microchannel walls, but also provide multiple reaction sites to subsequently attach bacteria capturing aptamers. Studies will be advanced to investigate aptamers with different types of linkers at different linkage length to the anchoring surfaces. To further enhance detection, rolling circle amplification (RCA) signal intensifications will also be used, effectively enhancing detection signals. Finally, microfluidics flow patterns will be studied to improve detection efficiency. ******Anticipated significance of the work: The proposed detection system is novel in that it offers not only rapid and sensitive detections, but also possibilities to integrate with other microfluidic on-chip functionalities, such as separator and concentrators. The proposed studies is a key component of the overall proposed detection system. If successfully implemented, the fully integrated detection platform will significantly reduce detection time and lower detection cost, thereby allowing safety authorities to extend their testing coverage and frequencies and playing more proactive roles in identifying possible contaminations and suspicious activities.