Conference Agenda

Optical affinity biosensors with single molecule sensitivity are reported based on a combination of optical and molecular interaction - based amplification. Plasmonically-enhanced fluorescence detection that is suitable for readout of sufficiently large sensor surface areas is implemented by the use of tailored metallic nanostructures. These metallic nanostructures are chemically modified with antifouling polymer-based biointerfaces for specific capture of target molecular species. The response to specific affinity binding events is further enhanced by rolling circle amplification, through enzyme-free catalytic hairpin assembly method, and affinity mediated transfer, in order to associate the individual affinity capture target molecules with bright fluorescence spots enabling counting of affinity captured target molecules (‘digital assay format’). The presented methods will be put to context with liquid biopsy – based lung and melanoma cancer diagnostics through ultrasensitive detection of trace amounts of specific biomarkers circulating in blood.

Support from Gesellschaft für Forschungsförderung Niederösterreich m.b.H. project LS20-014 ASPIS, Austrian Science Fund via the project DIPLAB (I 5119-B and 21-16729K), Czech Science Fund through the project APLOMA (22- 30456J), European Union’s Horizon Europe program project VerSiLiB (No 101046217) and Operational Programme Johannes Amos Comenius financed by European Structural and Investment Funds and the MEYS (Project No. SENDISO -CZ.02.01.01/00/22_008/0004596) is acknowledged.

Over recent decades, metallic nanostructures have emerged as pivotal components in biosensing applications due to their exceptional optical transduction properties. In this study, we present a novel approach by integrating hybrid plasmonic/dielectric materials to enhance the sensitivity of large-scale plasmonic arrays. Specifically, we propose refining the fabrication process for Gold Nanomushrooms by incorporating dielectric Silicon Nitride instead of traditional pillars. This strategic modification aims to yield sensors with a heightened responsiveness to refractive index variation, tailored to address the needs of biomedical applications.

A Metal-Enhanced Fluorescence (MEF) based immunosensor has been developed for the detection of prostate-specific antigen (PSA), a crucial biomarker for prostate cancer. The biosensor consists of gold nanoparticles (AuNPs) randomly immobilized onto a glass substrate via an electrostatic self-assembly technique. A sandwich scheme has been employed for PSA recognition, with antibodies as capture bioreceptors covalently immobilized onto the AuNPs surface and a top fluorescently labeled bioreceptors layer. The biosensor has been tested on real samples, successfully detecting PSA in human serum within a rapid 40-minute assay time, achieving a limit of detection (LOD) of 150 pg·mL-1.

We recently developed a peculiar disaggregation‒based colorimetric sensing scheme where stable and reversible clusters of functionalized Core@satellite magnetic nanoparticles (CSMPs) are first created by surfactant‒induced depletion‒related forces and then fragmented in response to the detection events. The fragmentation of CSMPs clusters entails an unexpected increase of the extinction intensity of the colloids. Here, we provide a theoretical foundation for such optical behaviour by first modelling both the CSMPs and CSMPs clusters, and then investigating their optical response by finite-difference time-domain simulations.

This paper presents the design and implementation of a tailored optical system for rapid characterization of transmission-based localized surface plasmon resonance (LSPR) biosensors. The system incorporates a motorized monochromator, offering extreme versatility in experimenting with wavelength resolution and bandwidth of the illumination. This setup streamlines the process of determining optimal chip design parameters such as the density of nanoparticles and the number of detection wavelengths required, as measurements are fully automated and software-driven. Furthermore, the system facilitates straightforward detection of manufacturing errors, including misaligned spots or inhomogeneous particle distribution, enhancing overall efficiency and reliability in biosensor evaluation.