Integrating advanced Microfluidic lateral flow systems with a finger-prick blood collection cartridge to create an all-in-one platform for point-of-care diagnostics

Rapid, point-of-care tests are critical for early diagnosis of disease and detection of biological threats. Lateral flow immunoassays (LFIAs) are well-suited for point-of-care testing due to their ease of use and straightforward readout. However, limitations in sensitivity, quantification, and integration into sample-to-result systems indicate the need for further advancements. This paper introduces a novel all-in-one LFIA that integrates a test strip with optimized geometry within a newly designed finger-prick blood collection cartridge. This innovative system offers an efficient solution for the detection and quantification of hepatitis B antigens, combining precision and user-friendliness in a single device. To enhance assay performance, the conventional test strip's response to the target protein was significantly improved by incorporating a constricted test zone and upstream mixing elements. To meet self-testing requirements, the blood collection cartridge incorporates an innovative two-step rotation mechanism that simplifies sample collection, processing, and application onto the test strip. Numerical simulations of flow dynamics and antibody-antigen interactions using COMSOL guided the optimization of the test strip geometry, achieving a substantial improvement in the limit of detection from 1.78 ± 0.08 to 0.55 ± 0.04 ng/mL compared to the classic rectangular strip geometry. The optimized design also increased analytical sensitivity from 1.4 ± 0.1 to 2.8 ± 0.1 RU.mL/ng. The system demonstrated complete functionality, from sample collection to analyte quantification. This integrated, user-friendly platform provides an advanced, sample-to-result diagnostic solution for detecting disease markers from finger-prick blood samples. Its simplicity makes it suitable for point-of-care testing, including home use by non-professionals.