title: Highly sensitive nanoparticle-based immunoassays with elemental detection: Application to Prostate-Specific Antigen quantification.
abstract: One of the major challenges in developing novel assay methods for the detection of biomolecules is achieving high sensitivity, because of the ultralow concentrations typically in clinical samples. Here, a Mn-doped ZnS quantum dots-based immunoassay platform is presented for highly sensitive detection of cancer biomarkers. Ultrahigh sensitivity is achieved through gold deposition on the surface of the nanoparticle tags acting as catalytic seeds, thus effectively amplifying the size of the metallic nanoparticles after the immunoassay and before the tag detection. Elemental mass spectrometry measurement of the gold content allowed detection of Prostate-Specific Antigen (PSA) at the low attog mL(-1) level. Moreover, the developed method showed not only an extremely high sensitivity for PSA detection but also a broad dynamic range, higher than 8 orders of magnitude, particularly useful for clinical studies involving quantitative detection of diverse biomarkers at their very different relevant concentration levels. Its applicability to discriminate small differences in PSA concentrations at low levels (few pgmL(-1)) in real serum samples was successfully evaluated.
authors.affiliation: Department of Physical and Analytical Chemistry, University of Oviedo, Julián Clavería 8, Oviedo 33006, Spain.
authors.forename: Marta
authors.initials: M
authors.lastname: Garcia-Cortes
authors.affiliation: Department of Physical and Analytical Chemistry, University of Oviedo, Julián Clavería 8, Oviedo 33006, Spain.
authors.forename: Jorge Ruiz
authors.initials: JR
authors.lastname: Encinar
authors.affiliation: Department of Physical and Analytical Chemistry, University of Oviedo, Julián Clavería 8, Oviedo 33006, Spain.
authors.forename: Jose M
authors.initials: JM
authors.lastname: Costa-Fernandez
authors.affiliation: Department of Physical and Analytical Chemistry, University of Oviedo, Julián Clavería 8, Oviedo 33006, Spain. Electronic address: asm@uniovi.es.
authors.forename: Alfredo
authors.initials: A
authors.lastname: Sanz-Medel
mesh_terms: D014408:Biomarkers, Tumor / Q000032:analysis / Q000097:blood; D015374:Biosensing Techniques / Q000295:instrumentation*; D004867:Equipment Design; D006046:Gold / Q000737:chemistry; D006801:Humans; D007118:Immunoassay / Q000295:instrumentation*; D057230:Limit of Detection; D053768:Metal Nanoparticles / Q000737:chemistry / Q000648:ultrastructure; D017430:Prostate-Specific Antigen / Q000032:analysis / Q000097:blood*; D045663:Quantum Dots / Q000737:chemistry* / Q000648:ultrastructure; D013440:Sulfides / Q000737:chemistry*; D017967:Zinc Compounds / Q000737:chemistry*
chemical_list: D014408:Biomarkers, Tumor; D013440:Sulfides; D017967:Zinc Compounds; D006046:Gold; D017430:Prostate-Specific Antigen; C031238:zinc sulfide
keywords: Biomarkers detection; Immunoassays; Mass spectrometry; Nanotechnology; Quantum dots