title: Ultrasensitive densitometry detection of cytokines with nanoparticle-modified aptamers.
abstract: BACKGROUND
  Aptamers mimic properties of antibodies and sometimes turn out to be even better than antibodies as reagents for assays. We describe the establishment of an ultrasensitive densitometry method for cytokine detection by nanoparticle (NP)-modified aptamers.
  
  
  METHODS
  The assay simultaneously uses a gold NP-modified aptamer and a biotin-modified aptamer to bind to the target protein, forming a sandwich complex. The absorbance signal generated by the aptamer-protein complex is amplified and detected with a microplate reader.
  
  
  RESULTS
  The assay for platelet-derived growth factor B-chain homodimer (PDGF-BB) was linear from 1 fmol/L to 100 pmol/L (R(2) = 0.9869). The analytical detection limit was 83 amol/L. The intraassay and interassay imprecision (CVs) was < or =7.5%. Serum concentrations of PDGF-BB determined with the gold NP-modified aptamer assay and with ELISA were not significantly different.
  
  
  CONCLUSIONS
  The gold NP-modified aptamer assay provides a fast, convenient method for cytokine detection and improves the detection range and the detection limit compared with ELISA.
authors: MOE Key Laboratory of Environment and Health, School of Public Health, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, People's Republic of China.
authors: Yuan-Yuan
authors: YY
authors: Li
authors: Chi
authors: C
authors: Zhang
authors: Bo-Sheng
authors: BS
authors: Li
authors: Li-Fan
authors: LF
authors: Zhao
authors: Xiao-Bo
authors: XB
authors: Li
authors: Wen-Jie
authors: WJ
authors: Yang
authors: Shun-Qing
authors: SQ
authors: Xu
mesh_terms: D052157:Aptamers, Nucleotide; D000077214:Becaplermin; D001710:Biotin; D016207:Cytokines / Q000097:blood*; D003720:Densitometry; D004797:Enzyme-Linked Immunosorbent Assay; D006046:Gold; D053768:Metal Nanoparticles; D010982:Platelet-Derived Growth Factor / Q000032:analysis*; D020574:Proto-Oncogene Proteins c-sis; D015203:Reproducibility of Results; D052156:SELEX Aptamer Technique; D012680:Sensitivity and Specificity; D012834:Silver
chemical_list: D052157:Aptamers, Nucleotide; D016207:Cytokines; D010982:Platelet-Derived Growth Factor; D020574:Proto-Oncogene Proteins c-sis; D000077214:Becaplermin; D012834:Silver; D001710:Biotin; D006046:Gold