Developing a Paper-Based Sensor for Cholesterol Measurement and Processing Images Using ImageJ

Cholesterol is an important fatty molecule that functions in maintaining the structural integrity and fluidity of the cell membrane. It is widely found throughout the human body, and the body uses cholesterol to produce vitamin D and bile acids that digest fats. Excess cholesterol in the blood causes cholesterol to accumulate in the blood vessels and thus narrowing and hardening them. Accurate determination of free cholesterol levels in blood serum and food is very important for diagnosis, treatment and prevention of related conditions. Microfluidic paper-based analytical devices (µPAD) offer different advantages such as low cost, ease of use and disposable (disposable) compared to other measurement methods. Here, a µPAD was developed using cholesterol oxidase, 3,3',5,5'-tetramethylbenzidine (TMB) and horseradish peroxidase (HRP) for cholesterol measurement. The sensors were tested with solutions containing cholesterol at different concentrations, and color changes in the detection areas were imaged and analyzed using ImageJ. The results showed that the sensor had a low detection limit for cholesterol. The sensor has great potential to be used in different fields from clinic to sports medicine.