Real-time analysis of dual-display phage immobilization and autoantibody screening using quartz crystal microbalance with dissipation monitoring.

Over the last three decades, phage display technology has been used for the display of target-specific biomarkers, peptides, antibodies, etc. Phage display-based assays are mostly limited to the phage ELISA, which is notorious for its high background signal and laborious methodology. These problems have been recently overcome by designing a dual-display phage with two different end functionalities, namely, streptavidin (STV)-binding protein at one end and a rheumatoid arthritis-specific autoantigenic target at the other end.

Aptamers targeting different functional groups of 17β-estradiol.

Aptamers, short synthetic ssDNA or RNA molecules with a specific three-dimensional structure, are promising recognition elements in biosensor technology. In vitro generation of aptamers with high sensitivity and specificity toward a broad range of analytes has been achieved using the systematic evolution of ligands by exponential enrichment (SELEX) process. This iterative pathway of aptamer generation consists of sequential positive and counterselection steps.

Construction of helper plasmid-mediated dual-display phage for autoantibody screening in serum.

M13 filamentous bacteriophage has been used in displaying disease-specific antibodies, biomarkers, and peptides. One of the major drawbacks of using phage in diagnostic assays is the aspecific adsorption of proteins leading to a high background signal and decreasing sensitivity. To deal with this, we developed a genetically pure, exchangeable dual-display phage system in which biomarkers and streptavidin-binding protein (SBP) are displayed at opposite ends of the phage.

Heat-transfer-based detection of SNPs in the PAH gene of PKU patients.

Conventional neonatal diagnosis of phenylketonuria is based on the presence of abnormal levels of phenylalanine in the blood. However, for carrier detection and prenatal diagnosis, direct detection of disease-correlated mutations is needed. To speed up and simplify mutation screening in genes, new technologies are developed.

Heat-transfer resistance at solid-liquid interfaces: a tool for the detection of single-nucleotide polymorphisms in DNA.

In this article, we report on the heat-transfer resistance at interfaces as a novel, denaturation-based method to detect single-nucleotide polymorphisms in DNA. We observed that a molecular brush of double-stranded DNA grafted onto synthetic diamond surfaces does not notably affect the heat-transfer resistance at the solid-to-liquid interface. In contrast to this, molecular brushes of single-stranded DNA cause, surprisingly, a substantially higher heat-transfer resistance and behave like a thermally insulating layer.

Nanocrystalline diamond impedimetric aptasensor for the label-free detection of human IgE.

Like antibodies, aptamers are highly valuable as bioreceptor molecules for protein biomarkers because of their excellent selectivity, specificity and stability. The integration of aptamers with semiconducting materials offers great potential for the development of reliable aptasensors. In this paper we present an aptamer-based impedimetric biosensor using a nanocrystalline diamond (NCD) film as a working electrode for the direct and label-free detection of human immunoglobulin E (IgE).

DNA sensors with diamond as a promising alternative transducer material.

Bio-electronics is a scientific field coupling the achievements in biology with electronics to obtain higher sensitivity, specificity and speed. Biosensors have played a pivotal role, and many have become established in the clinical and scientific world. They need to be sensitive, specific, fast and cheap.

Structural and optical properties of DNA layers covalently attached to diamond surfaces.

Label-free detection of DNA molecules on chemically vapor-deposited diamond surfaces is achieved with spectroscopic ellipsometry in the infrared and vacuum ultraviolet range. This nondestructive method has the potential to yield information on the average orientation of single as well as double-stranded DNA molecules, without restricting the strand length to the persistence length. The orientational analysis based on electronic excitations in combination with information from layer thicknesses provides a deeper understanding of biological layers on diamond.