On the importance of controlling film architecture in detecting prostate specific antigen

Author(s)

Graca, Juliana Santos ^[1] ; Miyazaki, Celina Massumi ^[1] ; Shimizu, Flavio Makoto ^[2] ; Volpati, Diogo ^[3] ; Mejia-Salazar, J. R. ^[2] ; Oliveira, Jr., Osvaldo N. ^[2] ; Ferreira, Marystela ^[1]

Affiliation

^[1] Univ Fed Sao Carlos, Ctr Sci & Technol Sustainabil, BR-18055720 Sorocaba, SP - Brazil

^[2] Univ Sao Paulo, Sao Carlos Inst Phys, POB 369, BR-13560970 Sao Carlos, SP - Brazil

^[3] Mid Sweden Univ, Dept Nat Sci, SE-85170 Sundsvall - Sweden

• Document type: Journal article
• Source: Applied Surface Science; v. 434, p. 1175-1182, MAR 15 2018.
• Web of Science Citations: 3

Abstract

Immunosensors made with nanostructured films are promising for detecting cancer biomarkers, even at early stages of the disease, but this requires control of film architecture to preserve the biological activity of immobilized antibodies. In this study, we used electrochemical impedance spectroscopy (EIS) to detect Prostate Specific Antigen (PSA) with immunosensors produced with layer-by-layer (LbL) films containing anti-PSA antibodies in two distinct film architectures. The antibodies were either adsorbed from solutions in which they were free, or from solutions where they were incorporated into liposomes of dipalmitoyl phosphatidyl glycerol (DPPG). Incorporation into DPPG liposomes was confirmed with surface plasmon resonance experiments, while the importance of electrostatic interactions on the electrical response was highlighted using the Finite Difference Time-Domain Method (FDTD). The sensitivity of both architectures was sufficient to detect the threshold value to diagnose prostate cancer (ca. 4 ng mL(-1)). In contrast to expectation, the sensor with the antibodies incorporated into DPPG liposomes had lower sensitivity, though the range of concentrations amenable to detection increased, according to the fitting of the EIS data using the Langmuir-Freundlich adsorption model. The performance of the two film architectures was compared qualitatively by plotting the data with a multidimensional projection technique, which constitutes a generic approach for optimizing immunosensors and other types of sensors. (C) 2017 Elsevier B.V. All rights reserved. (AU)

• FAPESP's process: 14/15093-7 - Study of nanostructured systems by surface plasmon resonance (SPR): applications in biosensing
• Grantee: Celina Massumi Miyazaki
• Support Opportunities: Scholarships in Brazil - Post-Doctoral
• FAPESP's process: 13/14262-7 - Nanostructured films from biologically-relevant materials
• Grantee: Osvaldo Novais de Oliveira Junior
• Support Opportunities: Research Projects - Thematic Grants
• FAPESP's process: 16/12311-9 - Transversal magneto-optical Kerr effect for the design and development of biosensors
• Grantee: Jorge Ricardo Mejía Salazar
• Support Opportunities: Scholarships in Brazil - Post-Doctoral
• FAPESP's process: 12/15543-7 - Biosensors to detect Escherichia coli using the concept of an extended electronic tongue
• Grantee: FLAVIO MAKOTO SHIMIZU
• Support Opportunities: Scholarships in Brazil - Post-Doctoral
• FAPESP's process: 14/17519-1 - Immobilization of metal nanoparticules in ultrathin films aiming biosensing
• Grantee: Marystela Ferreira
• Support Opportunities: Regular Research Grants
• FAPESP's process: 13/23288-0 - PSA detection using layer by layer films
• Grantee: Juliana Santos Graça
• Support Opportunities: Scholarships in Brazil - Master