Oral cavity cancer is one of the most common malignancies. Development of immunoassay based biosensor for interleukin-8 (IL-8) protein is required. The miniaturization of the device is also necessary in order to provide ready-touse portable diagnostic tools (point of care diagnostic) for clinical uses. In the current study, a compact, portable and reliable biomarker detecting and analyzing system is presented. The light absorption analysis was performed by a low-cost and portable optical sensor device. We used a programmable microcontroller unit (MCU) to operate the device. A digitalto-analog converter (DAC) was used to deliver a modulating signal to LEDs, and then the modulated light excited the samples in the microfluidic detection chamber. The signals from the sample and control group were obtained by two photodetectors individually. The photodetectors were amplified and demodulated through the lock-in amplifier, and digitized by analog-to-digital converters (ADC) to the MCU. After that, the analyzed data was uploaded to the smartphone via Bluetooth. The device demonstrates a good measurement accuracy and shorter detection time compared to conventional methods.