High-sensitive and high-efficient biochemical analysis method using a bionic electronic eye in combination with a smartphone-based colorimetric reader system

• A smartphone-based colorimetric reader was developed as Bionic e-Eye in biochemical analysis method.
• Bionic e-Eye using HSV color model achieved high-sensitive and high-efficient performance.
• Bionic e-Eye was optimized in system structure to obtain high stability and miniaturization.
• BCA and CCK8 assays are employed to compare Bionic e-Eye with MTPR.
• The study provides a promising platform for point-of-care (POC) detection device.

Bionic electronic eye (Bionic e-Eye), a developed smartphone-based colorimetric reader system, consists of smartphone or pad (iPhone 4s or iPad 3) as detection instrument and portable accessory as illumination provider integrating with a wide-angle lens, a piece of lowest-power electro luminescent and a custom-made dark hood. A 96-well microtiter plate (MTP) was positioned on the electro luminescent and Bionic e-Eye captures the detection images by the back camera of smartphone. Being similar to human visual system, the hue, saturation and value (HSV, also called hex cone model) color model was employed in image processing algorithm of Bionic e-Eye. Optimized system dimension was determined by the system steadiness experiment of different photograph distances. Moreover, the commercially available bicinchoninic acid (BCA) protein assay and cell counting kit (CCK8) assay were carried out to evaluate this Bionic e-Eye. Analytical performance of Bionic e-Eye had the better precision, higher sensitivity than microtiter plate reader (MTPR) and previous smartphone-based colorimetric reader for both two assays. Also, Bionic e-Eye using optical image detection had simultaneous and synchronous working mode, while MPTR using machine moving detection had asynchronous working mode in high throughput detection. Therefore, Bionic e-Eye will be an ideal point-of-care (POC) colorimetric detection device in the field of clinical application, industrial quality control, environment monitoring, and food assessment.