A microfluidic platform for foodborne pathogenic bacteria detections

近年来食源性疾病的爆发导致食品安全检查当局和食品工业对食源性病原体快速、敏感和高通量方法和仪器的需求增长。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，并使食品安全当局能够快速应对食源性疾病暴发和食品供应链上的生物恐怖袭击等事件。为此，本研究计划是开发一种敏感且低成本的基于微流体的检测系统，该系统可以避免对培养富集过程的需要，并在短时间内完成对真实食品的整个测试。******提出的程序集成了样品制备和样品检测芯片上的功能。它包括一个分离器，用于从均质现实世界的食品样品中去除大的食品颗粒，一个浓缩器，用于从样品中去除液体，以及一个检测器，用于有效捕获和检测目标细菌。因此，输入样本可以在系统内以这种连续流方式进行处理和随后的分析。对于目前的发现补助金（DG）申请，主要目标是开发一种超灵敏的微流体装置，提供灵敏和快速的检测。为了实现这一目标，我们建议用树状大分子和结合目标细菌特异性适配体对微流体通道壁进行表面修饰。这不仅可以减少由于与微通道壁的非特异性结合而产生的背景信号，而且还可以提供多个反应位点，以便随后附着捕获适体的细菌。研究将进一步探讨具有不同类型连接体的适配体与锚定表面的不同连接长度。为了进一步增强检测，还将使用滚动圆放大（RCA）信号增强，有效增强检测信号。最后，将研究微流体的流动模式，以提高检测效率。******工作的预期意义：所提出的检测系统是新颖的，因为它不仅提供快速和敏感的检测，而且还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检测系统的关键组成部分。如果成功实施，完全集成的检测平台将大大缩短检测时间，降低检测成本，从而使安全当局能够扩大检测范围和频率，并在识别可能的污染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.