title: Synthesis and characterization of double-layer quantum-dots-tagged microspheres.
abstract: Quantum-dots-tagged poly (styrene-acrylamide-acrylic acid) microspheres (QDsAAMs) were synthesized and modified with hydrazine hydrate through hydrazinolysis. Azidocarbonyl groups, which can be rapidly coupled with proteins under mild conditions, were introduced onto the surface of QDsAAM using azido reaction. Bovine serum albumin (BSA) was selected as model protein to be covalently immobilized on the azidocarbonyl QDsAAM. Instruments such as fluorescence microscope, optical microscope, confocal laser scanning microscope, UV-visible spectrometer, Fourier transform infrared spectrometer, size analyzer, and fluorescence spectrophotometer were used to characterize QDsAAM. Results showed that QDsAAM had a regular double-layer spherical shape and an average diameter of 11.2 microm. It also displayed high fluorescence intensity (lambda(ex)/lambda(em) = 250 nm/370 nm), which showed linearity with concentrations ranging from 3.0 x10(-3) to 90.0 x10(-3) g.L(-1). In addition, external factors such as pH and ionic strength exerted little influence on fluorescent characteristic. BSA immobilization indicated that QDsAAM with azidocarbonyl groups could be covalently coupled with BSA at the rate of 40 x10(-3) g/g (BSA/QDsAAM), while fluorescence linearity correlation was also found. This functional azidocarbonyl QDsAAM with sensitive fluorescence and active azidocarbonyl groups could be used as a promising fluorescent probe for quantitative detection, protein immobilization, and early rapid clinical diagnostics.
authors.affiliation: Key Laboratory of Biomedical Information Engineering of the Ministry of Education, School of Life Science and Technology, Xi'an Jiaotong University, Xi'an 710049, China.
authors.forename: Xinghua
authors.initials: X
authors.lastname: Pan
authors.forename: Maolin
authors.initials: M
authors.lastname: Lu
authors.forename: Daocheng
authors.initials: D
authors.lastname: Wu
authors.forename: Lili
authors.initials: L
authors.lastname: Gai
mesh_terms: D003460:Crystallization / Q000379:methods*; D008856:Microscopy, Fluorescence / Q000379:methods*; D008863:Microspheres; D015336:Molecular Probe Techniques; D045663:Quantum Dots; D012710:Serum Albumin, Bovine / Q000737:chemistry*; D013050:Spectrometry, Fluorescence / Q000379:methods*
chemical_list: D012710:Serum Albumin, Bovine