title: A quantum dot-based optical immunosensor for human serum albumin detection.
abstract: In this study, a CdSe/ZnS quantum dot (QD)-based immunosensor using a simple optical system for human serum albumin (HSA) detection is developed. Monoclonal anti-HSA (AHSA) immobilized on 3-aminopropyltriethoxysilane (APTES)-modified glass was used to capture HSA specifically. Bovine serum albumin (BSA) was used to block non-specific sites. The solution, containing AHSA-QD complex prepared by mixing biotinylated polyclonal anti-HSA and streptavidin coated QD, was used to conjugate with the HSA molecules captured on AHSA/BSA/APTES-modified glass for the modification of HSA with QD. A simple optical system, comprising a diode laser (405 nm), an optical lens, a 515-nm-long pass filter, and an Si-photodiode, was used to detect fluorescence and convert it to photocurrent. The current intensity was determined by the amount of QD specifically conjugated with HSA, and was therefore HSA-concentration-dependent and could be used to quantify HSA concentration. The detection limit of the pure QD solution was ~3.5×10(-12) M, and the detection limit for the CdSe/ZnS QD-based immunosensor developed in this study was approximately 3.2×10(-5) mg/ml. This small optical biosensing system shows considerable potential for future applications of on-chip liver-function detection.
authors.affiliation: National Tsing Hua University, Department of Materials Science and Engineering, Hsinchu, Taiwan.
authors.forename: Meng-Che
authors.initials: MC
authors.lastname: Tu
authors.forename: Yun-Tzu
authors.initials: YT
authors.lastname: Chang
authors.forename: Yu-Ting
authors.initials: YT
authors.lastname: Kang
authors.forename: Hwan-You
authors.initials: HY
authors.lastname: Chang
authors.forename: Pin
authors.initials: P
authors.lastname: Chang
authors.forename: Tri-Rung
authors.initials: TR
authors.lastname: Yew
mesh_terms: D000911:Antibodies, Monoclonal / Q000737:chemistry / Q000276:immunology; D015374:Biosensing Techniques / Q000379:methods*; D005453:Fluorescence; D006801:Humans; D007118:Immunoassay; D007834:Lasers; D057230:Limit of Detection; D055096:Optical Devices; D045663:Quantum Dots; D012709:Serum Albumin / Q000302:isolation & purification*
chemical_list: D000911:Antibodies, Monoclonal; D012709:Serum Albumin