A pump-free paper/PDMS hybrid microfluidic chip for bacteria enrichment and fast detection

Zhengshan Zhu; Zilan Lv; Li Wang; Haolan Tan; Yi Xu; Shunbo Li; Li Chen

doi:10.1016/j.talanta.2024.126155

A pump-free paper/PDMS hybrid microfluidic chip for bacteria enrichment and fast detection

Talanta. 2024 Apr 26:275:126155. doi: 10.1016/j.talanta.2024.126155. Online ahead of print.

Authors

Zhengshan Zhu¹, Zilan Lv², Li Wang¹, Haolan Tan³, Yi Xu¹, Shunbo Li⁴, Li Chen⁵

Affiliations

¹ Key Laboratory of Optoelectronic Technology and Systems, Ministry of Education & Key Disciplines Laboratory of Novel Micro-Nano Devices and System Technology, College of Optoelectronic Engineering, Chongqing University, Chongqing, 400044, China; International R & D Center of Micro-nano Systems and New Materials Technology, Chongqing University, Chongqing, 400044, China.
² Chongqing Key Laboratory of Translational Research for Cancer Metastasis and Individualized Treatment, Chongqing University Cancer Hospital, Chongqing, 400030, China.
³ School of Chemistry and Chemical Engineering, Chongqing University, Chongqing, 4001331, China.
⁴ Key Laboratory of Optoelectronic Technology and Systems, Ministry of Education & Key Disciplines Laboratory of Novel Micro-Nano Devices and System Technology, College of Optoelectronic Engineering, Chongqing University, Chongqing, 400044, China; International R & D Center of Micro-nano Systems and New Materials Technology, Chongqing University, Chongqing, 400044, China. Electronic address: shunbo.li@cqu.edu.cn.
⁵ Key Laboratory of Optoelectronic Technology and Systems, Ministry of Education & Key Disciplines Laboratory of Novel Micro-Nano Devices and System Technology, College of Optoelectronic Engineering, Chongqing University, Chongqing, 400044, China; International R & D Center of Micro-nano Systems and New Materials Technology, Chongqing University, Chongqing, 400044, China. Electronic address: CL2009@cqu.edu.cn.

PMID: 38678928
DOI: 10.1016/j.talanta.2024.126155

Abstract

Developing portable and sensitive biosensors for bacteria detection is highly demanded due to their association with environmental and food safety. Paper-based microfluidic chip is the suitable candidate for constructing pump-free biosensor since paper is hydrophilic, low-cost and easy to use. However, the contradiction between sensitivity and small sample volume seriously affects the application of paper-based chip for bacteria detection. Here, a new microfluidic biosensor, combining large PDMS reservoir for sample storage, hydrophilic paper substrate for pump-free water transport, coated microspheres for bacteria capture and super absorbent resin for water absorption, is designed for the detection of bacteria in aqueous samples. Once the sample solution is introduced in the reservoir, water will automatically flow through the gaps between microspheres and the target bacteria will be captured by the aptamer coated on the surface. To facilitate PDMS reservoir bonding and ensure water transport, the upper side of paper substrate is coated with Polyethylenimine modified PDMS and the bottom side is kept unchanged. After all the solution is filtrated, fluorescent dye strained bacteria are enriched on the microspheres. The fluorescent intensity representing the number of bacteria captured is then measured using a portable instrument. Through the designed microfluidic biosensor, the bacteria detection can be achieved with 2 mL sample solution in less than 15 min for water or 20 min for diluted milk. A linear range from 10 CFU/mL to 1000 CFU/mL is obtained. The paper-based 3D biosensor has the merits of low-cost, simple operation, pump-free and high sensitivity and it can be applied to the simultaneous detection of multiple bacteria via integrating different aptamers.

Keywords: Bacteria biosensor; Fluorescent detection; Hybrid microfluidic chip; Paper/PDMS; enrichment.