Handheld Device for Saliva Pretreatment to Improve Cortisol Detection

Area of Science:

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

Background:

• Salivary cortisol analysis is a noninvasive alternative to blood tests.
• Saliva's viscosity and interfering components (mucins, proteins) limit current diagnostic assays.
• Effective sample pretreatment is crucial for reliable saliva-based diagnostics.

Purpose of the Study:

• To develop a handheld device for effective saliva pretreatment for point-of-care cortisol detection.
• To address limitations posed by salivary viscosity and interfering substances.
• To enhance the reliability and sensitivity of lateral flow assays (LFAs) for salivary cortisol.

Main Methods:

• Development of the SaliFilter device utilizing a filtration mechanism.
• Evaluation of device performance through turbidity measurements, protein quantification, and SDS-PAGE.
• Assessment of treated saliva's impact on capillary flow and LFA performance.
• Determination of cortisol detection limit using the SaliFilter-LFA system.

Main Results:

• SaliFilter efficiently removed high-molecular-weight mucins and salivary proteins.
• Pretreated saliva showed improved capillary flow, enabling stable and reliable LFA operation.
• Cortisol detection achieved a limit of detection of 1.47 ng mL⁻¹ with enhanced signal reproducibility.

Conclusions:

• The SaliFilter device offers a practical and portable solution for saliva sample pretreatment.
• This strategy significantly improves analytical sensitivity and reliability for point-of-care cortisol testing.
• The approach is suitable for decentralized settings and self-monitoring applications.