title: SPAD aptasensor for the detection of circulating protein biomarkers.
abstract: The need for decentralized clinical tests together with the concept of time and cost saving are pushing the development of portable, miniaturized, compact biosensors with diagnostic and prognostic purpose. Here, we propose an innovative detection system based on a Single Photon Avalanche Diode (SPAD) with high sensitivity and low noise, crucial features for an efficient chemiluminescence biosensor. The SPAD detector, having 60 µm diameter, has a Photon Detection Efficiency higher than 55% at 425 nm and a Dark Count Rate lower than 100 Hz at room temperature. Our design allows a good optical coupling efficiency between sample and detector. A specific biofunctional surface was implemented taking advantage of aptamers, short DNA sequences having high selectivity and affinity toward their targets. We successfully detected physiological levels of Vascular Endothelial Growth Factor (VEGF), a circulating protein biomarker highly correlated with cancer. The SPAD aptasensor showed a Limit of Detection (LoD) in the pM range, stability (up to 42 days) and re-usability (up to seven cycles). This compact biosensor is therefore a promising step toward the actual use of portable microdevices in diagnostics.
authors: Fondazione Bruno Kessler, Laboratory of Biomolecular Sequence and Structure Analysis for Health, via Sommarive 18, 38123 Povo (Trento), Italy. Electronic address: pasqua@fbk.eu.
authors: Laura
authors: L
authors: Pasquardini
authors: DII -Department of Industrial Engineering, University of Trento, via Sommarive 9, 38123 Povo (Trento), Italy.
authors: Lucio
authors: L
authors: Pancheri
authors: Fondazione Bruno Kessler, Laboratory of Biomolecular Sequence and Structure Analysis for Health, via Sommarive 18, 38123 Povo (Trento), Italy; CNR-Institute of Biophysics, Unit at Trento, via alla Cascata 56, 38123 Povo (Trento), Italy.
authors: Cristina
authors: C
authors: Potrich
authors: Fondazione Bruno Kessler, Center for Materials and Microsystem (CMM), via Sommarive 18, 38123 Povo (Trento), Italy.
authors: Alessandro
authors: A
authors: Ferri
authors: Fondazione Bruno Kessler, Center for Materials and Microsystem (CMM), via Sommarive 18, 38123 Povo (Trento), Italy.
authors: Claudio
authors: C
authors: Piemonte
authors: Fondazione Bruno Kessler, Laboratory of Biomolecular Sequence and Structure Analysis for Health, via Sommarive 18, 38123 Povo (Trento), Italy; CNR-Institute of Biophysics, Unit at Trento, via alla Cascata 56, 38123 Povo (Trento), Italy.
authors: Lorenzo
authors: L
authors: Lunelli
authors: Department of Oncology, University of Torino and Institute for Cancer Research at Candiolo (IRCC), Strada Provinciale 142, 10060 Candiolo (Torino), Italy.
authors: Lucia
authors: L
authors: Napione
authors: Department of Oncology, University of Torino and Institute for Cancer Research at Candiolo (IRCC), Strada Provinciale 142, 10060 Candiolo (Torino), Italy.
authors: Valentina
authors: V
authors: Comunanza
authors: Department of Oncology, University of Torino and Institute for Cancer Research at Candiolo (IRCC), Strada Provinciale 142, 10060 Candiolo (Torino), Italy.
authors: Maria
authors: M
authors: Alvaro
authors: Fondazione Bruno Kessler, Center for Materials and Microsystem (CMM), via Sommarive 18, 38123 Povo (Trento), Italy.
authors: Lia
authors: L
authors: Vanzetti
authors: Department of Oncology, University of Torino and Institute for Cancer Research at Candiolo (IRCC), Strada Provinciale 142, 10060 Candiolo (Torino), Italy.
authors: Federico
authors: F
authors: Bussolino
authors: Fondazione Bruno Kessler, Laboratory of Biomolecular Sequence and Structure Analysis for Health, via Sommarive 18, 38123 Povo (Trento), Italy.
authors: Cecilia
authors: C
authors: Pederzolli
mesh_terms: D052157:Aptamers, Nucleotide / Q000737:chemistry*; D015415:Biomarkers / Q000097:blood; D015374:Biosensing Techniques; D006801:Humans; D017785:Photons; D042461:Vascular Endothelial Growth Factor A / Q000097:blood / Q000302:isolation & purification*
chemical_list: D052157:Aptamers, Nucleotide; D015415:Biomarkers; D042461:Vascular Endothelial Growth Factor A
keywords: Aptamer; Chemiluminescence; SPAD; VEGF