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Toxicology Studies of Semiconductor Nanomaterials: Environmental Applications
Published in Suresh C. Pillai, Yvonne Lang, Toxicity of Nanomaterials, 2019
T. P. Nisha, Meera Sathyan, M. K. Kavitha, Honey John
Semiconductor materials can be additionally used as a surface-enhanced Raman scattering (SERS) substrate, which is a powerful tool that can be used for environmental monitoring, biomedical research, and chemical analysis due to its ultrasensitivity, non-destructing, and fingerprint effect. On a SERS substrate, the Raman signal of an analyte is amplified to 108 times or more, and hence can be used for the detection of trace amounts of herbicides like paraquat in water (Halvorson and Vikesland et al., 2010). Originally, the SERS activity was recognized only for noble metal nanoparticles and transition metals, but now some semiconductors also display notable SERS activity, viz. NiO, Ag2O, Cu2O, ZnO, TiO2, α-Fe2O3, and InAs QDs (Qi et al., 2014). Defect engineering by inducing oxygen vacancies in α-MoO3 transferred the weak SERS active substrate into a SERS-active substrate with an enhancement factor as high as 1.8 × 107 and a detection limit of 10−8 M for Rhodamine 6G, which is highest among the so-far reported semiconductors (Wu et al., 2017).
CRISPR-based biosensing systems: a way to rapidly diagnose COVID-19
Published in Critical Reviews in Clinical Laboratory Sciences, 2021
Majid Vatankhah, Amir Azizi, Anahita Sanajouyan Langeroudi, Sajad Ataei Azimi, Imaneh Khorsand, Mohammad Amin Kerachian, Jamshid Motaei
Rapid and cost-effective diagnosis with high specificity and sensitivity is crucial in the control, management and treatment of emerging COVID-19 infection. Various methods, including bead-based assays [62], PCR-based techniques, microfluidic platforms, digital droplet‐based systems [63], nucleic acid hybridization, and isothermal amplification, have been developed for the detection of nucleic acids in body fluids [34]. Most of these methods have tradeoffs in terms of simplicity, speed, cost, sensitivity and specificity, and they usually require sophisticated laboratory equipment and trained operators. Hence, there is a need to develop laboratory tests with high specificity and sensitivity, especially tests that can be used as POC diagnostic applications. Recently, various CRISPR-Cas platforms have been developed to detect viruses, identify low-frequency cancer mutations, and perform human genotyping. CRISPR-Cas platforms have several advantages such as high specificity to identify single-nucleotide variants (SNVs), ultrasensitivity, simplicity to fabricate, and high capability to be used for POC diagnostics [35,59]. CRISPR-Cas diagnostic biosensing systems, including SHERLOCK, SHERLOCKv2, HOLMES, HOLMESv2, DETECTR, CAS-EXPAR, NASBACC, STOPCovid, ctPCR, and AIOD-CRISPR, have been developed (Tables 1 and 2).
Selecting analytical biomarkers for diagnostic applications: a first principles approach
Published in Expert Review of Molecular Diagnostics, 2018
Samantha A. Byrnes, Bernhard H. Weigl
Looking forward, diagnostic test designs are beginning to strive for ultrasensitivity and quantification that can identify single target molecules; these types of tests are often referred to as digital assays because they rely on digitization of a signal where a positive signal indicates the presence of one target molecule and a negative indicates no target molecule. There are examples of digital NAATs in both the academic [47] and commercial sectors [48]. Recently, commercially available systems have been pushing toward digital immunoassays for quantification of proteins and larger-scale biomarker panels [49–53]. Currently, these types of tests are limited to higher resource facilities, but as they become more ubiquitous across a variety of settings they can lead to earlier disease detection. Additionally, future multiplexed or panel-based tests will help identify biomarkers indicative of specific treatment pathways [54,55].