No abstract

Bacteriophages, abbreviated as “phages”, have been developed as emerging nanoprobes for the detection of a wide variety of biological species, such as biomarker molecules and pathogens. Nanosized phages can display a certain length of exogenous peptides of arbitrary sequence or single-chain variable fragments (scFv) of antibodies that specifically bind to the targets of interest, such as animal cells, bacteria, viruses, and protein molecules. Metal nanoparticles generally have unique plasmon resonance effects. Metal nanoparticles such as gold, silver, and magnetism are widely used in the field of visual detection. A phage can be assembled with metal nanoparticles to form an organic–inorganic hybrid probe due to its nanometer-scale size and excellent modifiability. Due to the unique plasmon resonance effect of this composite probe, this technology can be used to visually detect objects of interest under a dark-field microscope. In summary, this review summarizes the recent advances in the development of phage-based probes for ultra-sensitive detection of various bio-species, outlining the advantages and limitations of detection technology of phage-based assays, and highlighting the commonly used editing technologies of phage genomes such as homologous recombination and clustered regularly interspaced palindromic repeats/CRISPR-associated proteins system (CRISPR-Cas). Finally, we discuss the possible scenarios for clinical application of phage-probe-based detection methods.

Cancer cell heterogeneity (CCH) is crucial in understanding cancer progression and metastasis. The CCH is one of the stumbling blocks in modern medicine's therapeutics and diagnostics . An in-vitro model of co-culture systems of MCF-7, HeLa, HEK-293, with THP-1 cells showed the occurrence of EpCAM positive (EpCAM+) and EpCAM negative (EpCAM−) heterogenetic cancer cell types labeled with the Quantum Dot antibody conjugates (QDAb). This in-vitro model study could provide insights into the role of rare cancer cells manifestation and their heterogeneity in metastatic progression and risk for severe infections in these patients. We successfully report the presence of CCH based on the fluorescence ratios of the co-cultured cancer cells when treated with the QDAb. These short-term mimic co-cultures give a compelling and quite associated model for assessing early treatment responses in various cancers.

Quantum dots (QD) with chemical composition QD 650CdSe=ZnS_Ni were successfully synthesized using a hydrothermal method and chemical precipitation. The nanocrystalline phase of the nanostructures was isolated and characterized using X-ray diffraction (XRD). The mean crystalline size doped core/shell Ni-dopant range was 9.0 ± 2.0 nm. The ferromagnetic data revealed the magnetic behaviour of QD 650CdSe=ZnS_Ni . The optical absorption measurements of these QDs were in the UV-visible light range 200-800 nm for a band gap value of 2.11 eV for QD 650 CdSe=ZnS_Ni . This means that pure QD 650CdSe and QD 650 CdSe=ZnS_Ni underwent a redshift when compared with bulk CdSe. For QD 650CdSe=ZnS_Ni there was successful uptake by cell lines including HeLa and MCF-7 for bioimaging and sorting applications.