The focus of this work was on designing a label-free DNA biosensor based on a super-sandwich assay using the electrochemical impedance spectroscopy technique. For this purpose, we designed a signal-up configuration whose linker probes could hybridize with two regions of the target DNA. In this configuration, the presented target DNA would effectively decrease the electron transfer, which would ...

Combining gold nanoparticles (GNPs) as fluorescence quencher and aptamer as probe, we have developed protein biosensors by using DNA-modified GNPs. We examined how the experimental design, such as the type of interaction between DNA strands and GNPs, temperature, and microenvironment of aptamer, influences the recognition ability of the biosensor. Under our experimental conditions, the recognit...

Fast, portable and sensitive analysis of E. coli is becoming an important challenge in many critical fields (e.g., food safety, environmental monitoring and clinical diagnosis). Thus, electrochemical biosensing of PCR amplicons from the bacterial genome has attracted reasonable research attention. In this work, we utilized a 3D DNA tetrahedral probe to establish a "sandwich-type" electrochemica...

Recent trends and challenges in the electrochemical methods for the detection of DNA hybridization are reviewed. Electrochemistry has superior properties over the other existing measurement systems, because electrochemical biosensors can provide rapid, simple and low-cost on-field detection. Electrochemical measurement protocols are also suitable for mass fabrication of miniaturized devices. El...

Proteases are closely associated with many pathological conditions. Efficient detection of protease activity may be useful for diagnosis, prognosis, and the development new therapeutic biomolecules. Fluorescent Resonance Energy Transfer (FRET) is defined as non-radioactive energy transfer that occurs between two fluorophores. proteins widely used in FRET biosensors because they can genetically ...

An electrochemical DNA biosensor based on recognition of double or single stranded DNA (ds-DNA/ss-DNA) immobilised on a self-assembled modified gold electrode is presented for denaturalisation and hybridisation detection. DNA is covalently bond on a self assembled 3-mercaptopropionic acid monolayer by using water soluble N-3(dimethylaminopropyl)-N ́ethylcarbodiimide hydrochloride (EDC) and Nhydr...

Nanopipette technology has been proven to be a label-free biosensor capable of identifying DNA and proteins. The nanopipette can include specific recognition elements for analyte discrimination based on size, shape, and charge density. The fully electrical read-out and the ease and low-cost fabrication are unique features that give this technology an enormous potential. Unlike other biosensing ...

We have developed a process based on hot-embossing lithography (HEL) to pattern at high-throughput micron-size through-holes in thin thermoplastic elastomer (TPE) membranes. This novel HEL process, which is shown to provide key advantages for microfluidics applications, was applied to the fabrication of highly-integrated 3D microfluidic devices designed to precisely immobilize biomolecules on t...

Optical biosensors are often used to measure kinetic rate constants associated with chemical reactions. Such instruments operate in the surface-volume configuration, in which ligand molecules are convected through a fluid-filled volume over a surface to which receptors are confined. Currently, scientists are using optical biosensors to measure the kinetic rate constants associated with DNA tran...

We have used time-of-flight secondary ion mass spectrometry (TOF-SIMS) to examine different immobilization processes of peptide nucleic acid (PNA) and their influence on the hybridization efficiency of unlabeled DNA fragments to complementary PNA. Two different approaches have been used to immobilize PNA onto Au surfaces. One method was to immobilize thiolated PNA in a single step reaction to t...