Disposable Paper-Based Biosensors: Optimizing the Electrochemical Properties of Laser-Induced Graphene

• Published in: ACS applied materials & interfaces 2022-07, Vol.14 (27), p.31109-31120
• Main Authors: Bhattacharya, Gourav, Fishlock, Sam J., Hussain, Shahzad, Choudhury, Sudipta, Xiang, Annan, Kandola, Baljinder, Pritam, Anurag, Soin, Navneet, Roy, Susanta Sinha, McLaughlin, James A.
• Format: Article
• Language: English
• Subjects: Functional Nanostructured Materials (including low-D carbon)
• ISSN: 1944-8244; 1944-8252
• DOI: 10.1021/acsami.2c06350

Laser-induced graphene (LIG) on paper substrates is a desirable material for single-use point-of-care sensing with its high-quality electrical properties, low fabrication cost, and ease of disposal. While a prior study has shown how the repeated lasing of substrates enables the synthesis of high-quality porous graphitic films, however, the process–property correlation of lasing process on the surface microstructure and electrochemical behavior, including charge-transfer kinetics, is missing. The current study presents a systematic in-depth study on LIG synthesis to elucidate the complex relationship between the surface microstructure and the resulting electroanalytical properties. The observed improvements were then applied to develop high-quality LIG-based electrochemical biosensors for uric acid detection. We show that the optimal paper LIG produced via a dual pass (defocused followed by focused lasing) produces high-quality graphene in terms of crystallinity, sp 2 content, and electrochemical surface area. The highest quality LIG electrodes achieved a high rate constant k 0 of 1.5 × 10–2 cm s–1 and a significant reduction in charge-transfer resistance (818 Ω compared with 1320 Ω for a commercial glassy carbon electrode). By employing square wave anodic stripping voltammetry and chronoamperometry on a disposable two-electrode paper LIG-based device, the improved charge-transfer kinetics led to enhanced performance for sensing of uric acid with a sensitivity of 24.35 ± 1.55 μA μM–1 and a limit of detection of 41 nM. This study shows how high-quality, sensitive LIG electrodes can be integrated into electrochemical paper analytical devices.