Phage M13KO7 detection with biosensor based on imaging ellipsometry and AFM microscopic confirmation

Acoustical Slot Mode Sensor for the Rapid Coronaviruses Detection

A method for the rapid detection of coronaviruses is presented on the example of the transmissible gastroenteritis virus (TGEV) directly in aqueous solutions with different conductivity. An acoustic sensor based on a slot wave in an acoustic delay line was used for the research. The addition of anti-TGEV antibodies (Abs) diluted in an aqueous solution led to a change in the depth and frequency of resonant peaks on the frequency dependence of the insertion loss of the sensor. The difference in the output parameters of the sensor before and after the biological interaction of the TGE virus in solutions with the specific antibodies allows drawing a conclusion about the presence/absence of the studied viruses in the analyzed solution. The possibility for virus detection in aqueous solutions with the conductivity of 1.9–900 μs/cm, as well as in the presence of the foreign viral particles, has been demonstrated. The analysis time did not exceed 10 min.

Phage Display Technology and its Applications in Cancer Immunotherapy

Background:

Phage display is an effective technology for generation and selection targeting protein for a variety of purpose, which is based on a direct linkage between the displayed protein and the DNA sequence encoding it and utilized in selecting peptides, improving peptides affinity and indicating protein-protein interactions. Phage particles displaying peptide have the potential to apply in the identification of cell-specific targeting molecules, identification of cancer cell surface biomarkers, identification anti-cancer peptide, and the design of peptide-based anticancer therapy.

Method/Results:

Literature searches, reviews and assessments about Phage were performed in this review from PubMed and Medline databases.

Conclusion:

The phage display technology is an inexpensive method for expressing exogenous peptides, generating unique peptides that bind any given target and investigating protein-protein interactions. Due to the powerful ability to insert exogenous gene and display exogenous peptides on the surface, phages may represent a powerful peptide delivery system that can be utilized to develop rapid, efficient, safe and inexpensive cancer therapy methods.

A simple and fast method for discrimination of phage and antibiotic contaminants in raw milk by using Raman spectroscopy

Phage and antibiotic in raw milk poses significant risks for starter culture activity in fermented products. Therefore, rapid detection of phage and antibiotic contaminations in raw milk is a crucial process in dairy science. For this purpose, a preliminary novel method for detection of phage and antibiotic was developed by using Raman spectroscopy. Streptococcus thermophilus phages and ampicillin which are quite important elements in dairy industry were used as model. The phage and antibiotic samples were added to raw milk separately, and Raman measurements were carried out. The obtained spectra were processed with a chemometric method. In this study, it has been demonstrated that the presence of phage has a titer sufficient to stop the fermentation (107 pfu/ml), and antibiotic in a concentration which inhibits the growth of starter cultures (0.5 µg/ml) in raw milk could be discriminated through Raman spectroscopy with a short analysis time (30 min).

Joint detection of tumor markers with imaging ellipsometry biosensor

Tumor marker detection contributes to the early diagnosis of cancers. However, due to the lack of detection specificity, its results cannot act as a direct evidence to confirm cancer occurrence in clinic. Joint detection of tumor markers may improve the detection specificity. As a trial for clinical diagnosis of hepatocellular carcinoma, α-fetoprotein, α-l-fucosidase and ferritin have been combined and detected with a label-free, phase sensitive and high throughput imaging ellipsometry biosensor (IEB). Eighty-two sera have been quantitatively detected with IEB and the results are in agreement with the clinical standard approaches. Evaluated by receiver operating characteristic analysis, the specificity of joint detection improves remarkably with IEB for hepatocellular carcinoma. It can be foreseen that the joint detection of tumor markers with IEB has a potential for clinical cancer diagnosis.

Analysis of interactions between SNARE proteins using imaging ellipsometer coupled with microfluidic array

The soluble N-ethylmaleimide-sensitive factor attachment receptor (SNARE) proteins are small and abundant membrane-bound proteins, whose specific interactions mediate membrane fusion during cell fusion or cellular trafficking. In this study, we report the use of a label-free method, called imaging ellipsometer to analyze the interactions among three SNAREs, namely Sec22p, Ykt6p and Sso2p. The SNAREs were immobilized on the silicon wafer and then analyzed in a pairwise mode with microfluidic array, leading us to discover the interactions between Ykt6p and Sso2p, Sec22p and Sso2p. Moreover, by using the real-time function of the imaging ellipsometer, we were able to obtain their association constants (K_A) of about 10⁴ M⁻¹. We argue that the use of imaging ellipsometer coupled with microfluidic device will deepen our understanding of the molecular mechanisms underlying membrane fusion process.

Nano-hard template synthesis of pure mesoporous NiO and its application for streptavidin protein immobilization

A simple and efficient immobilization of streptavidin protein (with hexa-histidine tag) onto the surface of mesoporous NiO is described. Before immobilization of streptavidin protein (with hexa-histidine tag) onto the surface of mesoporous NiO, we first synthesized well-organized mesoporous NiO by a nanocasting method using mesoporous silica SBA-15 as the hard template. Then, the well-organized mesoporous NiO particles were characterized by small angle x-ray diffraction (XRD), wide angle XRD, nitrogen adsorption/desorption, and transmission electron microscopy (TEM). TEM and small angle XRD suggested the formation of mesoporous NiO materials, whereas the wide angle XRD pattern of mesoporous NiO indicated that the nickel precursor had been transformed into crystalline NiO. The N2 sorption experiments demonstrated that the mesoporous NiO particles had a high surface area of 281 m2 g(-1), a pore volume of 0.51 cm3 g(-1) and a pore size of 4.8 nm. Next, the immobilization of streptavidin protein (with hexa-histidine tag) onto the surface of mesoporous NiO was studied. Detailed analysis using gel electrophoresis confirmed that this approach can efficiently bind his-tagged streptavidin onto the surface of mesoporous NiO material since the mesoporous NiO provides sufficient surface sites for the binding of streptavidin via non-covalent ligand binding with the histidine tag.

Microfluidic designs and techniques using lab-on-a-chip devices for pathogen detection for point-of-care diagnostics

Effective pathogen detection is an essential prerequisite for the prevention and treatment of infectious diseases. Despite recent advances in biosensors, infectious diseases remain a major cause of illnesses and mortality throughout the world. For instance in developing countries, infectious diseases account for over half of the mortality rate. Pathogen detection platforms provide a fundamental tool in different fields including clinical diagnostics, pathology, drug discovery, clinical research, disease outbreaks, and food safety. Microfluidic lab-on-a-chip (LOC) devices offer many advantages for pathogen detection such as miniaturization, small sample volume, portability, rapid detection time and point-of-care diagnosis. This review paper outlines recent microfluidic based devices and LOC design strategies for pathogen detection with the main focus on the integration of different techniques that led to the development of sample-to-result devices. Several examples of recently developed devices are presented along with respective advantages and limitations of each design. Progresses made in biomarkers, sample preparation, amplification and fluid handling techniques using microfluidic platforms are also covered and strategies for multiplexing and high-throughput analysis, as well as point-of-care diagnosis, are discussed.

Protein microarray biosensors based on imaging ellipsometry techniques and their applications

After years of development, biosensors based on imaging ellipsometry and biosensors based on total internal reflection imaging ellipsometry have been successfully implemented in various engineering systems. Their experimental setups, detection principles, and biological and clinical applications are briefly reviewed.

Detection of avian influenza virus subtype H5 using a biosensor based on imaging ellipsometry

A novel method is reported for the detection of avian influenza virus subtype H5 using a biosensor based on high spatial resolution imaging ellipsometry (IE). Monoclonal antibodies specific to H5 hemagglutinin protein were immobilized on silicon wafers and used to capture virus particles. Resultant changes on the surface of the wafers were visualized directly in gray-scale on an imaging ellipsometry image. This preliminary study has shown that the assay is rapid and specific for the identification of avian influenza virus subtype H5. Compared with lateral-flow immunoassays, this biosensor not only has better sensitivity, but can also simultaneously perform multiplexed tests. These results suggest that this biosensor might be a valuable diagnostic tool for avian influenza virus detection.