μPADs on Centrifugal Microfluidic Discs for Rapid Sample-to-Answer Salivary Diagnostics

Area of Science:

• Biomedical Engineering
• Analytical Chemistry
• Point-of-Care Diagnostics

Background:

• Noninvasive point-of-care testing (POCT) is crucial for contagious disease screening.
• Microfluidic paper-based analytical devices (μPADs) offer low-cost, adaptable platforms for POCT.
• Integrated sample-to-answer systems are needed for efficient POCT.

Purpose of the Study:

• To develop a generic POCT platform integrating a centrifugal microfluidic disc with μPADs for salivary diagnostics.
• To achieve efficient saliva treatment and sample-to-answer analysis.
• To demonstrate the platform's capability for detecting SARS-CoV-2 biomarkers.

Main Methods:

• Fabrication of a custom centrifugal microfluidic disc integrated with μPADs.
• Optimization of μPAD surface chemistry and protein immobilization for SARS-CoV-2 Nucleocapsid (N) protein detection.
• Testing the integrated device with pseudovirus samples in saliva.

Main Results:

• The integrated device demonstrated efficient saliva treatment.
• Detection of SARS-CoV-2 N protein down to 10 pg mL^-1 with a dynamic range of 10-1000 pg mL^-1.
• Assay time of 8 minutes achieved with high specificity and comparable performance to commercial tests.

Conclusions:

• The integrated centrifugal microfluidic disc and μPADs platform enables rapid, sensitive, and specific salivary diagnostics.
• This technology holds significant potential for noninvasive POCT of contagious diseases.
• The developed platform offers a viable alternative to existing commercial test strips for salivary analysis.