Do it yourself protocol to fabricate dual-detection paper-based analytical device for salivary biomarker analysis

This paper describes the design and construction of dual microfluidic paper-based analytical devices (dual-mu PADs) as a lab-on-paper platform involving a do-it-yourself fabrication protocol. The device comprises a colorimetric and electrochemical module to obtain a dual-mode signal readout sensing strategy. A 3D pen polymeric resin was used to prepare graphite carbon-based electrodes and hydrophobic barriers on paper substrates. The proposed carbon-based ink was employed to manufacture electrodes on paper based on a stencil-printing approach, which were further characterized by electrochemical and morphological analyses. The analytical performance of the dual-mu PADs was simultaneously evaluated for lactate, pH, nitrite, and salivary amylase (sAA) analysis. To demonstrate the proof-of-concept, saliva samples collected from both healthy individuals and those with periodontitis were successfully tested to demonstrate the feasibility of the proposed devices. Samples collected from individuals previously diagnosed with periodontitis showed high levels of nitrite and sAA (> 94 mu mol L-1 and > 610 U mL(-1)) in comparison with healthy individuals (<= 16 mu mol L-1 and 545 U mL(-1)). Moreover, periodontitis saliva resulted in acid solution and almost null lactate levels. Notably, this protocol supplies a simple way to manufacture dual-mu PADs, a versatile platform for sensitive detecting of biomarkers in saliva playing a crucial role towards the point-of-care diagnosis of periodontal disease.

Automated summary

This paper presents the design and construction of dual microfluidic paper-based analytical devices (dual-mu PADs) as a do-it-yourself lab-on-paper platform. The devices utilize both colorimetric and electrochemical modules to achieve signal readout sensing. The fabrication process involves using a 3D pen polymeric resin to create graphite carbon-based electrodes and hydrophobic barriers on paper substrates. The performance of the dual-mu PADs was evaluated for the analysis of lactate, pH, nitrite, and salivary amylase (sAA), with successful testing on saliva samples from healthy individuals and those with periodontitis. The devices show potential for point-of-care diagnosis of periodontal disease by sensitive detection of biomarkers in saliva.