Recombinase polymerase amplification in combination with electrochemical readout for sensitive and specific detection of PIK3CA point mutations.

As part of the ongoing evolution towards personalized anticancer therapy, mutation screening is becoming increasingly important and, therefore, also alternative detection strategies that allow for fast genetic diagnostics at the point of care. In the case of breast cancer, detecting cancer-associated point mutations in the PIK3CA gene is of particular importance for treatment decisions. We developed a recombinase polymerase amplification assay combined with an enzyme-linked electrochemical assay on multi-channel screen-printed gold sensors for specific and highly sensitive detection of three PIK3CA point mutations (H1047R, E545K, and E542K).

Enhanced multicolor resonant-optical-assay with direct text output.

The effectiveness of a novel multicolor biochip boosted by reducing cluster repulsion and in-situ silver enhancement has been demonstrated by using anti-serum albumine antibodies conjugated to gold nanoparticles on a vacuum metalized plastic film coated with nano-resonance driving ceramic multilayers. A dense and smooth vacuum deposited SiO approximately 1.6 top layer (50 to 300 nm thick) on a flexible thermoplastic polymer poly-ethylene-terephthalate-chip functionalized via poly-ethylenimine monolayer coating and chemical cross-linking was employed to immobilize capture antibodies.

From lateral flow devices to a novel nano-color microfluidic assay.

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.

Direct optical visualization of DNA-DNA interaction by nanoparticle-capture on resonant PET-films.

Based on the understanding of the absorption behavior of metal nanoparticles we aimed at the direct detection of sub-monomolecular layers of DNA with the naked eye. This extremely sensitive detection needs optical amplification techniques to be used in replacement of nanoparticle-aggregates applied e.g.

Tuning the setup of sputter-coated multilayers in nanocluster-based signal-enhancing biochips for optimal performance in protein and DNA assays.

In biochip development two issues are critical: stable and specific immobilization of the ligand and achievement of high signal-to-background ratio. In this work we have addressed these issues for the development of biochips, produced by sputtering multilayers of thin metal films, metal oxides, and metal nitrides (tens to hundreds of nanometers thick) onto glass wafers. Optimized surfaces have shown good results in genomic and proteomic experiments with biochips based on surface-enhanced fluorescence and absorption techniques.

Supported membrane nanodevices.

Supported membrane nanodevices are based on natural or artificial ion channels embedded in a lipid membrane deposited on a chip wafer. Membrane conductance is modulated by biorecognitive events, with the use of intrinsic binding sites of the ion channel or via artificial sites fused to the channel protein. Artificial ion gates are constructed by coupling a specific ligand for the analyte near the channel entrance or a site important to triggering channel conformation.

Phage display antibody-based proteomic device using resonance-enhanced detection.

The combination of phage display antibody arrays with a novel nanotransducer technique based on resonant nanoparticles in a nanosandwiched film enables the sensitive parallel screening of proteins. Using the resonance of nanoparticles with their induced mirror dipoles in a thin-film structure, limitations of fluorophores, such as unspecific background and nonvisibility to the eye, can be overcome, thereby leading to an optical signal significantly more sensitive than that of standard colloid techniques. The signal can be both directly observed as a color change of a microdot at the sensor surface and tuned throughout the visible range of the spectrum.

Structural behavior of nanometric carbohydrate films transduced by a resonant technique.

New optical nanoresonance effects enabled us to study the effect of ions on nanometric carbohydrate thin layers on chips. Immobilization was done via spin coating of the derivatized carbohydrate polymer at a metallized chip surface forming ultrathin films (about 50-300 nm thick) followed by photochemical cross-linking. Deposition of metal-nanoclusters, synthesized by chemical means and sputter coating on top of the polymer, induced an optical resonance effect, which transduced changes of polymer structure quantitatively into an optical signal that can be observed directly as resonance shift of a narrow optical peak.