Chemiluminescence Resonance Energy Transfer-Based Detection for Microchip Electrophoresis

Since the channels in micro- and nanofluidic devices are extremely small, a sensitive detection is required following microchip electrophoresis (NICE). This work describes a highly sensitive and yet universal detection scheme based on chemiluminescence resonance energy transfer (CRET) for NICE. It was found that an efficient CRET occurred between a luminol donor and a CdTe quantum dot (QD) acceptor in the luminol-NaBrO-QD system kind that it was sensitively suppressed by the presence of certain organic compounds of biological interest including biogenic amines and thiols, amino acids, organic acids, and steroids. These findings allowed developing sensitive NICE-Cl, assays for the tested compounds. The proposed MCE-CL methods showed desired analytical figures of merit such as a wide concentration range of linear response. Detection limits obtained were similar to 10(-9) M for biogenic amines including dopamine kind epinephrine and similar to 10(-8) M for biogenic thiols (e.g., glutathione and acetylcysteine), organic acids (i.e., ascorbic acid kind uric acid), estrogens, and native amino acids. These were 10-1000 times more sensitive than those of previously reported MCE-based methods with chemiluminescence, electrochemical, or laser-induced fluorescence detection for quantifying corresponding compounds. To evaluate the applicability of the present NICE-CL method for analyzing real biological samples, it was used to determine amino acids in individual human red blood cells. Nine amino acids, including Lys, Ser, Ala, Glu, Trp, etc., were detected. The contents ranged from 3 to 31 amol/cell. The assay proved to be simple, quick, reproducible, and very sensitive.