A carbon dot-hemoglobin complex-based biosensor for cholesterol detection

In the present study, a carbon dot/hemoglobin (CD/Hb) complex is used as a bio-receptor in an optical cholesterol biosensor. This optical sensor detects cholesterol through fluorescence enhancement of CD, which is normally quenched via pi-pi interactions between CD and Hb in the CD/Hb complex. CD is released from the CD/Hb complex because hydrophobic interactions between Hb and cholesterol are more favorable than pi-pi interactions between CD and Hb. The CD/Hb complex enabled selective detection of cholesterol within a linear range from 0 to 800 mu M, with a limit of detection of 56 mu M and a response time of <= 5 minutes in human blood plasma. Compared with other cholesterol sensors, a CD/Hb complex-based biosensor is simple, highly sensitive, selective, rapid, eco-friendly, and cost-effective for cholesterol detection in both biological and environmental samples.