On-chip handling of solutions and electrochemiluminescence detection of amino acids

Abstract On-chip determination of amino acids was conducted by electrochemiluminescence (ECL) following microfluidic transport, mixing of solutions, and generation of ECL. The fabricated system consisted of a polydimethylsilixane (PDMS) substrate with a flow channel structure and three-electrode systems formed on a glass substrate that resulted in the microfluidic transport and the ECL. An amino acid solution and a reagent solution containing tris(2,2′-bipyridyl)ruthenium(II) (Ru(bpy)32+) were transported by electrowetting by applying a negative potential to gold working electrodes formed along the flow channels. The two solutions were then mixed in the mixing channel using an additional gold working electrode formed between the electrodes for transport. ECL was generated by applying a potential to a platinum working electrode formed in the mixing channel. The ECL from l -proline, l -lysine, l -leucine, l -valine, and l -histidine was examined. Clear ECL was observed, and its intensity depended on the concentration of the amino acids. By increasing the pH by mixing solutions and generating the oxidized form, Ru(bpy)33+, on the chip, the detection sensitivity could be improved. l -proline showed the strongest ECL, and concentrations of the nM order could be detected.

[1]  A. Campagnari,et al.  Detection of biological threat agents by immunomagnetic microsphere-based solid phase fluorogenic- and electro-chemiluminescence. , 2000, Biosensors & bioelectronics.

[2]  Milena Koudelka-Hep,et al.  Microreactor and electrochemical detectors fabricated using Si and EPON SU-8 , 2000 .

[3]  T. Nieman,et al.  Chemiluminescence detection using regenerable tris(2,2'-bipyridyl)ruthenium(II) immobilized in Nafion. , 1992, Analytical chemistry.

[4]  Donald R. Bobbitt,et al.  Role of electron-donating/withdrawing character, pH, and stoichiometry on the chemiluminescent reaction of tris(2,2'-bipyridyl)ruthenium(III) with amino acids , 1992 .

[5]  Neil W. Barnett,et al.  Analytical applications of tris(2,2′-bipyridyl)ruthenium(III) as a chemiluminescent reagent , 1999 .

[6]  A. Bard,et al.  Electrogenerated chemiluminescent determination of oxalate. , 1983, Analytical chemistry.

[7]  E. Kobatake,et al.  Electrochemical luminescence immunosensor for α-fetoprotein , 1996 .

[8]  H. B. Halsall,et al.  Microfluidic immunosensor systems. , 2005, Biosensors & bioelectronics.

[9]  Masayoshi Esashi,et al.  Microflow devices and systems , 1994 .

[10]  G. Greenway,et al.  Tris(2,2-bipyridyl)ruthenium (II) chemiluminescence in a microflow injection system for codeine determination , 2000 .

[11]  D. R. Bobbitt,et al.  Effect of pH on the reaction of tris(2,2'-bipyridyl)ruthenium(III) with amino-acids: Implications for their detection. , 1991, Talanta.

[12]  D. Figeys,et al.  Lab-on-a-chip: a revolution in biological and medical sciences , 2000, Analytical chemistry.

[13]  Jens Anders Branebjerg,et al.  Microfluidics-a review , 1993 .

[14]  D. R. Bobbitt,et al.  Chemiluminescent detection of amino acids using in situ generated Ru(bpy)3+3 , 1994 .

[15]  L. Tobias,et al.  A highly sensitive electrochemiluminescence immunoassay for interferon alfa-2b in human serum. , 1997, Journal of immunological methods.

[16]  A. Manz,et al.  Micro total analysis systems. Recent developments. , 2004, Analytical chemistry.

[17]  Hiroaki Suzuki,et al.  Microfluidic transport based on direct electrowetting , 2004 .

[18]  Jan H. J. Fluitman,et al.  Towards integrated microliquid handling systems , 1994 .

[19]  Wataru Satoh,et al.  On-chip microfluidic transport and mixing using electrowetting and incorporation of sensing functions. , 2005, Analytical chemistry.

[20]  D. Erickson,et al.  Integrated microfluidic devices , 2004 .

[21]  R. A. Kamin,et al.  Electrochemiluminescence detection for development of immunoassays and DNA probe assays for clinical diagnostics. , 1991, Clinical chemistry.

[22]  Milena Koudelka-Hep,et al.  On-chip generation and detection of electrochemiluminescence , 1998 .

[23]  J. Baret,et al.  Electrowetting: from basics to applications , 2005 .

[24]  N. Danielson,et al.  Generation of chemiluminescence upon reaction of aliphatic amines with tris(2,2'-bipyridine)ruthenium(III) , 1987 .