A handheld contactless conductivity detector for monitoring the desalting of low-volume virus and cell samples

Yiren Cao; Zhimin Tao; Youli Tian; Ke-Er Chen; Lu Zhang; Jicun Ren; Hua Xiao; Qiang Zhang; Weiwen Liu; Chengxi Cao

doi:10.1016/j.bios.2023.115482

A handheld contactless conductivity detector for monitoring the desalting of low-volume virus and cell samples

Biosens Bioelectron. 2023 Oct 1:237:115482. doi: 10.1016/j.bios.2023.115482. Epub 2023 Jun 16.

Authors

Yiren Cao¹, Zhimin Tao², Youli Tian³, Ke-Er Chen⁴, Lu Zhang³, Jicun Ren⁵, Hua Xiao³, Qiang Zhang², Weiwen Liu⁶, Chengxi Cao⁷

Affiliations

¹ School of Sensing Science and Engineering, School of Electronic Information and Electrical Engineering, Shanghai Jiao Tong University, Shanghai, 200240, China; School of Chemistry and Chemical Engineering, Shanghai Jiao Tong University, Shanghai, 200240, China.
² School of Sensing Science and Engineering, School of Electronic Information and Electrical Engineering, Shanghai Jiao Tong University, Shanghai, 200240, China.
³ School of Life Science and Biotechnology, State Key Laboratory of Microbial Metabolism, Shanghai Jiao Tong University, Shanghai, 200240, China.
⁴ School of Chemical and Environmental Engineering, Shanghai Institute of Technology, Shanghai, 201418, China.
⁵ School of Chemistry and Chemical Engineering, Shanghai Jiao Tong University, Shanghai, 200240, China.
⁶ School of Sensing Science and Engineering, School of Electronic Information and Electrical Engineering, Shanghai Jiao Tong University, Shanghai, 200240, China. Electronic address: weiwenliu@sjtu.edu.cn.
⁷ School of Sensing Science and Engineering, School of Electronic Information and Electrical Engineering, Shanghai Jiao Tong University, Shanghai, 200240, China; School of Life Science and Biotechnology, State Key Laboratory of Microbial Metabolism, Shanghai Jiao Tong University, Shanghai, 200240, China. Electronic address: cxcao@sjtu.edu.cn.

PMID: 37406479
DOI: 10.1016/j.bios.2023.115482

Abstract

Desalting of biosamples is crucial for analytical techniques intolerant to abundant salts. However, there is no simple tool to monitor the desalting of low-volume biosamples so far. Here we developed a handheld capacitively coupled contactless conductivity detector (hC⁴D) as a miniaturized device to measure the conductivity of 75 μL biosamples. Polyether-ether-ketone (PEEK) tubing was selected as the sample reservoir for sample loading via a pipette. Another pipetting of air pushed the sample solution out of the tubing to recollect the sample. Owing to the low sample consumption and easy sample recollection, hC4D is advantageous for testing expensive biosamples, such as viruses and cells. In addition, the whole process of sample injection, conductivity measurement, recollection, and calibration of conductivity can be completed within 1 min. To verify the feasibility of hC⁴D, we monitored the desalting progress of gel filtration (GF) of 200 μL blood samples, ultrafiltration (UF) of 300 μL virus samples, and dialysis of 7 mL cell samples. Three rounds of GF and UF completely removed the salts but led to poor sample recovery. In contrast, low concentrations of residual salts remained and better recovery was achieved after two rounds of GF and UF. We further utilized the hC⁴D to monitor the dialysis and tuned the salt concentration in the cell sample, such that we maintained the viability of cells in a low conductivity environment. These results indicated that hC⁴D is a promising tool for optimizing the desalting procedure of low-volume biosamples.

Keywords: Adeno-associated virus; C(4)D; Electrophoresis; Handheld device; Sample desalting; Smartphone-based monitoring.

MeSH terms

Biosensing Techniques*
Electric Conductivity
Electrophoresis, Capillary* / methods
Ketones
Polyethylene Glycols
Salts

Substances

Salts
Ketones
Polyethylene Glycols