title: Nonamplification Sandwich Assay Platform for Sensitive Nucleic Acid Detection Based on AuNPs Enumeration with the Dark-Field Microscope.
abstract: A simple and efficient assay platform with high sensitivity, convenient implementation, and moderate cost in reagents and instrumentation is most appropriate for routine applications. On the basis of the gold nanoparticle (AuNP) enumeration signal readout mode established in our laboratory, we have developed a nonamplification sandwich assay for nucleic acid detection with the 3 fM limit of detection for a sequence related to Alzheimer's disease. This AuNP counting based method takes advantages of the distinctive and strong localized surface plasmon resonance light scattering with the dark-field microscope and magnetic separation. It is shown that the presence of 20 nM random DNA sequence or calf thymus DNA with a mass up to 10(6)-fold of the targets do not significantly interfere with the assay signal. The spike recoveries of Hela cell lysate sample at 109.3% for 20 pM target and 110.5% for 100 pM target indicate the potential of this proposed method in practical sample applications. This nonamplification sandwich assay platform in principle is applicable to other assays such as the immunoassay and thus would be expected to find a breadth of applications that can make the best use of the simplicity and sensitivity.
authors.affiliation: Beijing National Laboratory for Molecular Sciences (BNLMS), Key Laboratory of Bioorganic Chemistry and Molecular Engineering of Ministry of Education, Institute of Analytical Chemistry, College of Chemistry and Molecular Engineering, Peking University , Beijing, 100871, China.
authors.forename: Tian
authors.initials: T
authors.lastname: Li
authors.affiliation: Division of Nano Metrology and Materials Measurement, National Institute of Metrology , Beijing, 100029, China.
authors.forename: Xiao
authors.initials: X
authors.lastname: Xu
authors.affiliation: Suzhou Nanomicro Technology Company Limited , Suzhou, Jiangsu 215123, China.
authors.forename: Guoqing
authors.initials: G
authors.lastname: Zhang
authors.affiliation: Beijing National Laboratory for Molecular Sciences (BNLMS), Key Laboratory of Bioorganic Chemistry and Molecular Engineering of Ministry of Education, Institute of Analytical Chemistry, College of Chemistry and Molecular Engineering, Peking University , Beijing, 100871, China.
authors.forename: Ruoyun
authors.initials: R
authors.lastname: Lin
authors.affiliation: Beijing National Laboratory for Molecular Sciences (BNLMS), Key Laboratory of Bioorganic Chemistry and Molecular Engineering of Ministry of Education, Institute of Analytical Chemistry, College of Chemistry and Molecular Engineering, Peking University , Beijing, 100871, China.
authors.forename: Yang
authors.initials: Y
authors.lastname: Chen
authors.affiliation: Beijing National Laboratory for Molecular Sciences (BNLMS), Key Laboratory of Bioorganic Chemistry and Molecular Engineering of Ministry of Education, Institute of Analytical Chemistry, College of Chemistry and Molecular Engineering, Peking University , Beijing, 100871, China.
authors.forename: Chenxi
authors.initials: C
authors.lastname: Li
authors.affiliation: Beijing National Laboratory for Molecular Sciences (BNLMS), Key Laboratory of Bioorganic Chemistry and Molecular Engineering of Ministry of Education, Institute of Analytical Chemistry, College of Chemistry and Molecular Engineering, Peking University , Beijing, 100871, China.
authors.forename: Feng
authors.initials: F
authors.lastname: Liu
authors.affiliation: Beijing National Laboratory for Molecular Sciences (BNLMS), Key Laboratory of Bioorganic Chemistry and Molecular Engineering of Ministry of Education, Institute of Analytical Chemistry, College of Chemistry and Molecular Engineering, Peking University , Beijing, 100871, China.
authors.forename: Na
authors.initials: N
authors.lastname: Li
mesh_terms: D000818:Animals; D015374:Biosensing Techniques; D002417:Cattle; D004247:DNA / Q000032:analysis*; D006046:Gold / Q000737:chemistry*; D006367:HeLa Cells; D006801:Humans; D053768:Metal Nanoparticles / Q000737:chemistry*; D008853:Microscopy; D020349:Surface Plasmon Resonance
chemical_list: D006046:Gold; D004247:DNA