title: Parallel optical read-out of micromechanical pillars applied to prostate specific membrane antigen detection.
abstract: Micro and nanomechanical resonators represent a promising platform for proteins label-free detection because of their extreme sensitivity, fast response and low cost. Micro-pillars are columnar resonators that can be easily arranged in dense arrays of several thousand sensors in a squared mm. To exploit such a large density, however, a method for tracking independently micropillars resonance frequency is required. Here we present a detection method based on CCD imaging and software image analysis, which can measure the resonance frequency of tens of pillars in parallel. Acquiring simultaneously the frequency shift of up to 40 sensors and applying a proper statistical analysis, we were able to overcome the variability of the single measures improving the device sensitivity at low analyte concentration range. As a proof of concept, this method has been tested for the detection of a tumor marker, the Prostate Specific Membrane Antigen (PSMA). Pillars have been functionalized with an antibody against PSMA. The tumor marker (PSMA) has been detected in a range of concentrations between 300 pM and 100 nM, in buffer and in diluted bovine serum. The sensitivity of our method was limited only by the affinity constant of the antigen-antibody recognition. Moreover, this detection technique demonstrated to be effective in the 1-6 nM range, which is the window of PSMA concentration of clinical interest.
authors.affiliation: CNR-IOM, Area Science Park, Basovizza S.S. 14Km 163.5, 34149 Trieste, Italy; University of Udine, Biological and Medical Science, Ospedale della Misericordia, 33100 Udine, Italy. Electronic address: tardivo@iom.cnr.it.
authors.forename: Martina
authors.initials: M
authors.lastname: Tardivo
authors.affiliation: CNR-IOM, Area Science Park, Basovizza S.S. 14Km 163.5, 34149 Trieste, Italy; University of Trieste, Piazzale Europa, 34127 Trieste, Italy.
authors.forename: Valeria
authors.initials: V
authors.lastname: Toffoli
authors.affiliation: Department of Pathology and Diagnostics, University of Verona Policlinico "G.B. Rossi", P.le L. Scuro, 10 37134 Verona, Italy.
authors.forename: Giulio
authors.initials: G
authors.lastname: Fracasso
authors.affiliation: CNR-IOM, Area Science Park, Basovizza S.S. 14Km 163.5, 34149 Trieste, Italy; University of Trieste, Piazzale Europa, 34127 Trieste, Italy.
authors.forename: Daniele
authors.initials: D
authors.lastname: Borin
authors.affiliation: CNR-IOM, Area Science Park, Basovizza S.S. 14Km 163.5, 34149 Trieste, Italy.
authors.forename: Simone
authors.initials: S
authors.lastname: Dal Zilio
authors.affiliation: Nanostructures and Optics Laboratory, Department of Chemical Sciences University of Padova, Via Marzolo 1 35131 Padova, Italy.
authors.forename: Andrea
authors.initials: A
authors.lastname: Colusso
authors.affiliation: University of Trieste, Piazzale Europa, 34127 Trieste, Italy.
authors.forename: Sergio
authors.initials: S
authors.lastname: Carrato
authors.affiliation: University of Udine, Biological and Medical Science, Ospedale della Misericordia, 33100 Udine, Italy.
authors.forename: Giacinto
authors.initials: G
authors.lastname: Scoles
authors.affiliation: Nanostructures and Optics Laboratory, Department of Chemical Sciences University of Padova, Via Marzolo 1 35131 Padova, Italy.
authors.forename: Moreno
authors.initials: M
authors.lastname: Meneghetti
authors.affiliation: Department of Pathology and Diagnostics, University of Verona Policlinico "G.B. Rossi", P.le L. Scuro, 10 37134 Verona, Italy.
authors.forename: Marco
authors.initials: M
authors.lastname: Colombatti
authors.affiliation: CNR-IOM, Area Science Park, Basovizza S.S. 14Km 163.5, 34149 Trieste, Italy.
authors.forename: Marco
authors.initials: M
authors.lastname: Lazzarino
mesh_terms: D055910:Antibodies, Immobilized / Q000737:chemistry; D014408:Biomarkers, Tumor / Q000097:blood; D015374:Biosensing Techniques / Q000295:instrumentation*; D004867:Equipment Design; D006801:Humans; D057230:Limit of Detection; D008297:Male; D055617:Micro-Electrical-Mechanical Systems / Q000295:instrumentation*; D011467:Prostate / Q000473:pathology; D017430:Prostate-Specific Antigen / Q000097:blood*; D011471:Prostatic Neoplasms / Q000097:blood / Q000175:diagnosis
chemical_list: D055910:Antibodies, Immobilized; D014408:Biomarkers, Tumor; D017430:Prostate-Specific Antigen
keywords: Micromechanical sensors; Parallel optical read-out detection; Prostate Specific Membrane Antigen