Analytical Sciences

Evaluation of PAMAM Dendrimers (G3, G4, and G5) in the Construction of a SPR-based Immunosensor for Cardiac Troponin T

Juliana de F. GIAROLA,*,** Dênio E. P. SOUTO,*** and Lauro T. KUBOTA*,**

*Institute of Chemistry, University of Campinas (UNICAMP), Campinas, SP, 13083-970, Brazil
**National Institute of Science & Technology of Bioanalytics (INCTBio), Brazil
***Department of Chemistry, Federal University of Paraná (UFPR), Curitiba, PR, 81530 900, Brazil

An immunosensor was developed using a SAM of an alkanethiol associated with PAMAM(G4) dendrimers based on surface plasmon resonance (SPR) to enhance the sensitivity for troponin T detection in blood samples. The feasibility of using three-dimensional platforms based on dendrimers for the development of immunosensors was demonstrated by evaluating three different generations of these dendrimers (G3, G4, and G5) to detect troponin T. The results showed the efficiency of these 3D platforms in anchoring biomolecules, amplifying the detection of troponin T. The sandwich assay showed good performance for troponin T detection, using secondary monoclonal antibodies, in the concentration range of 5 – 300 ng mL⁻¹ (0.14 – 8.67 nmol L⁻¹), R² = 0.991, with the LOD of 3.6 ng mL⁻¹. The sandwich assay’s applicability was demonstrated by evaluating a secondary polyclonal antibody’s performance in the concentration range of 3 – 30 ng mL⁻¹, R² = 0.998, with the LOD of 0.98 ng mL⁻¹. The immunosensor was applied to determine troponin T in blood plasma samples from healthy patients, with an average recovery of 88 to 104%. The performance of the SPR-based immunosensor indicates reliable results and is expected to contribute to the rapid diagnosis of heart attack, with reduced costs.

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