background: among diverse protein purification systems, affinity chromatography is the most attractive one in the purification process of coagulation factors. coagulation factor vii is a plasma serine protease that has a significant role in natural human hemostasis and its recombinant form such as aryoseventm, has been applied in clinical treatment of bleeding disorders. immunoaffinity chromato...

Conjugation of DNAs to defined locations on a protein surface will offer powerful tools for positioning functional groups and molecules in biological and biomedical studies. However, tagging protein with DNA is challenging in physiological environments, which requires a bioorthogonal approach. Here we report a chemical solution to selectively conjugate DNA aptamer with a protein by protein-apta...

We report on the direct electrochemical detection of aptamer-protein interactions, namely between a DNA aptamer and lysozyme (LYS) based on electrochemical impedance spectroscopy (EIS) technique. First, the affinity of the aptamer to LYS and control proteins was presented by using filter retention assay. An amino-modified version of the DNA aptamer-recognizing lysozyme was covalently immobilize...

A label-free, homogeneous aptamer-based sensor strategy was designed for the facile colorimetric detec-tion of small target molecules. The format relied on the target-induced protection of DNA aptamer fromthe enzymatic digestion and its transduction into a detectable signal through the length-dependentadsorption of single-stranded DNA onto unmodified gold nanoparticles (AuNPs). The ...

Nucleic acid aptamers to HIV-1 reverse transcriptase (RT) are potent inhibitors of DNA polymerase function in vitro, and they have been shown to inhibit viral replication when expressed in cultured T-lymphoid lines. We monitored RT inhibition by five RNA pseudoknot RNA aptamers in a series of biochemical assays designed to mimic discrete steps of viral reverse transcription. Our results demonst...

Background: Salmonella is one of the most common food-borne pathogens that can cause illness. In this study, the sensitivity and the specificity of Aptamer-Magnetic bead Separation-Polymerase Chain Reaction (AMS-PCR) method were determined for Salmonella spp. detection. Methods: Different concentrations of Salmonella enterica were mixed with streptavidin-magnetic beads coated with biotinylated...

Single-stranded DNA sequences that are highly specific for a target ligand are called aptamers. While the incorporation of aptamer sequences into stem-loop molecular beacons has become an essential tool in optical biosensors, the design principles that determine the magnitude of binding affinity and its relationship to placement of the aptamer sequence in the stem-loop architecture are not well...

Background: Artificial oligonucleotides like DNA or RNA aptamers can be used as biodiagnostic alternatives for antibodies to detect pathogens. Comparing to antibodies, artificial oligonucleotides are produced easily at lower costs and are more stable. Neisseria meningitidis, the causative agent of meningitis, is responsible for about 1% of infections in an epidemic period. Specific DNA aptamers...

We applied Systematic Evolution of Ligands by EXponential enrichment using Small Cell Lung Cancer (SCLC) cells. A DNA aptamer was identified and evaluated by fluorescent confocal microscopy and flow cytometry. Our results showed that the DNA aptamer binds to molecules that exist predominantly on target SCLC cell surfaces compared with other types of SCLC cells.

Aptamers are valuable tools that provide great potential to develop cost-effective diagnostics and therapies in the biomedical field. Here, we report a novel DNA aptamer that folds into an unconventional G-quadruplex structure able to recognize and enter specifically into human Burkitt's lymphoma cells. We further optimized this aptamer to a highly versatile and stable minimized version. The mi...