Improving the performance of traditional diagnostic lateral flow assays combined with new manufacturing technologies is a primary goal in the research and development plans of diagnostic companies. Taking into consideration the components of lateral flow diagnostic test kits; innovation can include modification of labels, materials and device design. In recent years, Resonance-Enhanced Absorption (REA) of metal nano-particles has shown excellent applicability in bio-sensing for the detection of a variety of bio-molecular binding interactions. In a novel approach, we have now integrated REA-assays in a diagnostic microfluidic setup thus resolving the bottleneck of long incubation times inherent in previously existing REA-assays and simultaneously integrated automated fabrication techniques for diagnostics manufacture. Due to the roller-coating based technology and chemical resistance, we used PET-co-polyester as a substrate and a CO2 laser ablation system as a fast, highly precise and contactless alternative to classical micro-milling. It was possible to detect biological binding within three minutes – visible to the eye as colored text readout within the REA-fluidic device. A two-minute in-situ silver enhancement was able to enhance the resonant color additionally, if required.
Through a novel immunoassay nanoparticles (NPs) are captured via immune-reactive proteins and positioned as a sub-monolayer just a few nanometres above a light reflective surface. Here the particles and the mirror form a nanometric interference system with a tuneable colour throughout the full spectrum of light. This concept, which was inspired by nature ('wings of a butterfly'), creates an intensive colour clearly visible to the eye. By adaptation of this technique point-of-care (POC) tests become more sensitive, specific and time efficient. The novel format employs a combination of microfluidics and 'resonance-enhanced absorption' (REA) of gold and palladium nanoparticles quantifying interleukin-6 as an important parameter of acute sepsis. The colour intensity of the rapid test is boosted by using a subsequent silver enhancement. This performed in situ in just two to three minutes and a sensitivity of < 500 pg/ml was obtained.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.