A Lateral Flow Immunochromatographic Assay (LFIA) Strip Reader Based on Scheduler and 8051 IP Core

Lateral flow immunochromatographic assay (LFIA) testing is essential for accurate detection and diagnoses of diseases and physical conditions. However, the existing LFIA strip reader equipped with high cost of hardware confines its simplicity and portability. Therefore, this study develops a simple, low cost LFIA strip reader comprising 4 major modules - mechanical, optical, processing and control modules. The mechanical module pulls in and out the test strip automatically to be read by the optical module and the data processing module provides the test results by analyzing the data sent by the optical module. All the individual modules are controlled by a control module. To reduce the hardware budget and control complexity, a time-triggered cooperative (TTC) scheduler implemented on an 8051 IP core was chosen as control system. In addition, special, high sensitivity C-reactive protein (CRP) strips with 10 different concentrations were tested to evaluate the performance of the system. Further, a commercial ESEQuant lateral flow reader (QIAGEN, Germany) was tested as a comparative study. The test results show that the proposed reader was stable with a coefficient of variation (CV) factor within 3%. To test the qualitative performance of the system, each of the CRP concentration were examined for 10 times, which indicates that the system has a large dynamic detection range and good detection linearity (R-2 = 0.998). In short, the proposed LFIA strip reader has high potential relative to existing readers, especially in simplicity and cost.