Fabrication of graphene oxide-based pretreatment filter and Electrochemical-CRISPR biosensor for the field-ready cyanobacteria monitoring system

• Published in: Biosensors & bioelectronics 2023-10, Vol.237, p.115474-115474, Article 115474
• Main Authors: Kim, Gahyeon, Li, Yun Guang, Seo, Yoseph, Baek, Changyoon, Choi, Jin-Ha, Park, Hyunjun, An, Jeongyun, Lee, Myoungro, Noh, Seungwoo, Min, Junhong, Lee, Taek
• Format: Article
• Language: English
• Subjects: Aquatic ecosystem monitoring; Biosensor; Cyanobacteria; Hand-held filter; PCR-Free detection
• ISSN: 0956-5663; 1873-4235
• DOI: 10.1016/j.bios.2023.115474

Microcystis aeruginosa (M. aeruginosa) cause the eutrophication of lakes and rivers. To effectively control the overgrowth of M. aeruginosa, a suitable measurement method should be required in the aquatic fields. To address this, we developed a field-ready cyanobacterial pretreatment device and an electrochemical clustered regularly interspaced short palindromic repeats (EC-CRISPR) biosensor. The cyanobacterial pretreatment device consists of a syringe, glass bead, and graphene oxide (GO) bead. Then, the M. aeruginosa dissolved in the freshwater sample was added to fabricated filter. After filtration, the purified gene was loaded onto a CRISPR-based electrochemical biosensor chip to detect M. aeruginosa gene fragments. The biosensor was composed of CRISPR/Cpf1 protein conjugated with MXene on an Au microgap electrode (AuMGE) integrated into a printed circuit board (PCB). This AuMGE/PCB system maximizes the signal-to-noise ratio, which controls the working and counter electrode areas requiring only 3 μL samples to obtain high reliability. Using the extracted M. aeruginosa gene with a pre-treatment filter, the CRISPR biosensor showed a limit of detection of 0.089 pg/μl in fresh water. Moreover, selectivity test and matrix condition test carried out using the EC-CRISPR biosensor. These handheld pre-treatment kit and biosensors can enable field-ready detection of CyanoHABs.