Whole Blood Electrochemiluminescent Detection of Dopamine

Direct detection of medically relevant biomarkers in whole blood without the need for pretreatment or extraction is a great challenge for biomedical analysis and diagnosis. Electrochemical techniques, such as electrochemiluminescence (ECL), are promising tools for this area of analysis. ECL offers high sensitivities together with the ability to obtain time and spacial control over the process. This work exploits these features together with the low background signals obtained from ECL detection to clearly identify and quantify dopamine in whole blood with relative standard deviations lower than 5% (n = 5). This near-infrared quantum dot based ECL sensor displayed a linear response over the range 3.7 ≤ [dopamine] ≤ 450 μM, allowing the rapid detection of dopamine and providing a platform for future development. Significantly, the near-infrared quantum dots exhibited excellent penetrability through biological samples such as whole blood, and show the ECL detection of dopamine in whole blood for the first time. This will likely be at the forefront of development in biosensing and imaging fields in the foreseeable future.