SPAD aptasensor for the detection of circulating protein biomarkers

Laura Pasquardini, Lucio Pancheri, Cristina Potrich, Alessandro Ferri, Claudio Piemonte, Lorenzo Lunelli, Lucia Napione, Valentina Comunanza, Maria Alvaro, Lia Vanzetti, Federico Bussolino, Cecilia Pederzolli

Research output: Contribution to journalArticlepeer-review


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.

Original languageEnglish
Pages (from-to)500-507
Number of pages8
JournalBiosensors and Bioelectronics
Publication statusPublished - Jun 5 2015


  • Aptamer
  • Chemiluminescence
  • SPAD
  • VEGF

ASJC Scopus subject areas

  • Biophysics
  • Biomedical Engineering
  • Biotechnology
  • Electrochemistry
  • Medicine(all)


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