We propose a disruptive point-of-care (PoC) imaging platform based on lens-free interference phase-contrast imaging for rapid detection of biomarker such as for sepsis and potentially other diseases (e.g. cancer). It enables simultaneous analysis of potentially up to 10,000 functionalized microarray spots with different biomarkers with fast time-to-results (few minutes) and by consuming a small sample volume (~10 μL). The high sensitivity allows direct measurements of the biomarker binding without the use of fluorescent labels (e.g. ELISA) or microbial culture methods. In addition, adhoc plasmonic nano-structuring is utilized to significantly improve the sensitivity for biomarker detection (optical path difference ~Å) to concentration levels relevant for disease diagnosis.
The proposed technology incorporates a portable and low-cost lens-free imaging reader made of consumer electronic components, plasmonic microarrays with distinct functionalization, and user-friendly software based on a novel phaseshifting interferometry method for topography and refractive index analysis. Due to its compactness and cost-efficiency, we foresee a great potential for PoC applications, especially for the rapid detection of infectious diseases or lifethreatening conditions, e.g. sepsis, but also for clinical trials of drugs and food control.
A procedure for fabricating nanopatterned surfaces at the sub-500 nm scale comprising a hexagonal close packed array of bioadhesive gold nanoareas in a protein resistant matrix (PEO-like polymer), has been optimized. The surfaces were characterized by AFM analysis and their interaction with amino functionalised gold nanoparticles as models were investigated. The AFM images show the crystalline arrangement of nanopattern array and the localized adsorption of the H2N-Au nanoparticles in the bioadhesive nanoareas. A Surface Plasmon Resonance imaging (SPRi) system was used to assess the detection performances of these surfaces when employed as a transduction platform for studying biomolecule interactions. The investigated surfaces showed an enhancement of the affinity reaction efficiency with respect to the non structured surfaces. The obtained preliminary results show that nanostructuring the surfaces improve the binding site accessibility of the immobilized biological probes without significantly modifying the native biomolecule conformation.