In the present study, we fabricated a foldable all-in-one microdevice for the nucleic acid test (NAT) performing DNA extraction, polymerase chain reaction (PCR), and on-site colorimetric detection for point‐of‐care (POC) molecular diagnosis of multiple pathogens. The microdevice is composed of three layers. The top layer contains six filter paper discs pre-stored with PCR reagent. The middle layer contains six through-holes corresponding to the positions of six paper discs on the top layer, and was sealed by a flat bottom layer, forming six main chambers where commercially available FTA cards are stored. The intact bacteria samples were introduced into six main chambers for sample treatment – specifically, the isolation, purification, and storage of nucleic acids inside the FTA cards. After the main chambers were filled with water, the top layer was folded towards the middle layer. After 30 thermal cycles for PCR, targets were colorimetrically detected on chip by loading silver nitrate solution into the main chambers and illuminated by UV at 234 nm for 30 s. To examine the versatile applicability, the microdevice was used for the direct detection of three major foodborne pathogens: Salmonella spp., Staphylococcus aureus, and Escherichia coli O157:H7. The feasibility of the microdevice was also tested for detecting multidrug-resistant bacteria, Acinetobacter baumannii. Using the microdevice, multiple pathogens were detected with high specificity and sensitivity of 3.0×10² and 3.0×10³ CFU/sample for Gram-negative (Salmonella spp. and Escherichia coli O157:H7) and Gram-positive (Staphylococcus aureus) bacteria, respectively, in less than 2 h, making the microdevice highly suitable in low-resource settings.

在本研究中，我们制造了一种可折叠的多合一微设备，用于核酸测试（NAT），可进行DNA提取，聚合酶链反应（PCR）和现场比色检测，以用于即时护理（POC）分子诊断多种病原体。微型设备由三层组成。顶层包含六个预装有PCR试剂的滤纸圆盘。中间层包含六个通孔，对应于顶层上六个纸盘的位置，并由平坦的底层密封，形成了六个主腔，用于存储市售的FTA卡。将完整的细菌样本引入六个主要腔室中进行样本处理-特别是在FTA卡内分离，纯化和存储核酸。在主舱里装满水之后，顶层折叠到中间层。经过30个PCR的热循环后，通过将硝酸银溶液装入主室并在234 nm的紫外线下照射30 s，在芯片上比色检测目标。为了检查通用性，将微型设备用于直接检测三种主要食源性病原体：沙门氏菌，金黄色葡萄球菌和大肠杆菌O157：H7。微型设备的可行性也进行了检测，以检测耐多药细菌鲍曼不动杆菌。使用微装置，对革兰氏阴性菌（沙门氏菌和大肠杆菌O157：H7）和革兰氏阳性菌（金黄色葡萄球菌）具有3.0×10 ²和3.0×10 ³ CFU /样品的高特异性和灵敏度的多种病原体分别在不到2小时的时间内，使微型设备非常适合于资源匮乏的环境。