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Introduction
Published in Krishnendu Chakrabarty, Fei Su, Digital Microfluidic Biochips, 2018
Krishnendu Chakrabarty, Fei Su
Microfluidic biochips promise to revolutionize enzymatic analysis (e.g., glucose and lactate assays), DNA analysis (e.g., PCR and nucleic acid sequence analysis), proteomic analysis involving proteins and peptides, immunoassays, and toxicity monitoring [5,6]. An emerging application area for microfluidic biochips is clinical diagnostics, especially immediate point-of-care diagnosis of diseases [5,6]. Microfluidics can also be used for countering bioterrorism threats [7,8]. Microfluidics-based devices, capable of continuous sampling and real-time testing of air/water samples for biochemical toxins and other dangerous pathogens, can serve as an always-on “bio-smoke alarm” for early warning.
Recent Advancement and Combination of Different Molecular Tools and Techniques for Applications in Wastewater Treatment
Published in Maulin P. Shah, Wastewater Treatment, 2022
Ritwija Bhattacharya, Indraneel Rakshit, Aniruddha Mukhopadhyay, Pritha Bhattacharjee
The popularity of denaturing gradient gel electrophoresis (DGGE) is increasing manyfold as a huge number of studies are using this method. The principle is based on the variable mobility of denatured DNA fragments of the same size on gel due to their different nucleic acid sequence, directly reflecting the genetic diversity of the sample. DGGE also has been coupled with sequencing and in situ hybridization for better resolution. An interesting feature of DGGE is that it gives valuable insights into the dominant species present in the samples collected from activated sludge of WWTPs, although it is not as exhaustive as sequencing. Along with the samples from WWTPs, DGGE has also been employed to study complex microbial communities from the soil, food, microbial samples from the human intestine, etc. The most important aspect of this method is to study the dynamic changes of the microbial community in a large sample size. Multiple studies showed that DGGE is a useful tool to monitor different bacterial communities present in two different lagoons of a WWTP. It has helped to understand the successional changes of the bacterial community, Spatio-temporal distribution of sulfate-reducing bacteria in a microbial mat. DGGE analysis has also suggested that the elevated temperature of the thermophilic bioreactor has less species richness than the mesophilic bioreactor. It has also been employed to observe the change in the bacterial community in constantly stirred reactors, structure and dynamics of sulfate-reducing bacteria, and the effect of nitrate on bacterial biofilms. Although it has been very useful in the previously mentioned cases, there are several limitations to the application of DGGE. It is unable to differentiate small nucleotide changes. Different conditions of DGGE and choosing a different region of 16S rRNA gene might give different resolutions (Santegoeds et al. 1998).
Optical Nanosensors
Published in Vinod Kumar Khanna, Nanosensors, 2021
QDs are promising in microarrays (multiplex lab-on-a-chip devices), immunoassays (laboratory techniques that make use of the binding between an antigen and its homologous antibody in order to identify and quantify), and fluorescence in situ hybridization (the use of labeled nucleic acid sequence probes for the visualization of specific DNA or RNA sequences). Resolution of single nucleotide polymorphisms (SNPs) on cDNA arrays has been achieved for mutation in the human oncogene p53. Single nucleotide polymorphism (SNP) is a genetic sequence variation which affects only one of the nucleotides (adenine A, thymine T, cytosine C or guanine G) in a segment of a DNA molecule, e.g. it may involve replacement of the nucleotide cytosine with thymine in a stretch of DNA. Polymorphism is the occurrence of two or more different forms called phenotypes in a population of a species. A polymorph is one of the several forms in which an organism is found. An oncogene is a sequence of DNA that has been altered or mutated from its original form, the proto-oncogene. Onco-, from the Greek onkos, meaning “bulk,” or “mass,” refers to the tumor-causing ability of the oncogene. The p53 gene is a tumor-suppressor gene, its activity halting the formation of tumors. Mutations in p53 are found in most tumor types. A multiplexed analysis for the hepatitis B and hepatitis C viruses has been carried out by concurrently using QDs with peak luminescence at 566 and 668 nm (Ulgar and Krull 2009). Hepatitis B and C are viral infections that cause inflammation of the liver. Different viruses are known to cause these infections. Hepatitis B virus (HBV) is a partially double-stranded circular DNA virus while Hepatitis C virus (HCV) is an enveloped positive sense single-stranded RNA (+ssRNA) virus of Flaviviridae family. Here, the apparent sensitivity of QD arrays may be less than observed with organic fluorophores, because of their poor excitation efficiency. This shortcoming is overcome by using blue-shifted (a decrease in the wavelength of radiation) source and/or red-shifted (an increase in the wavelength of radiation) LEDs, wherever possible.
Potential strategies to prevent encrustations on urinary stents and catheters – thinking outside the box: a European network of multidisciplinary research to improve urinary stents (ENIUS) initiative
Published in Expert Review of Medical Devices, 2021
Ali Abou-Hassan, Alexandre Barros, Noor Buchholz, Dario Carugo, Francesco Clavica, Petra de Graaf, Julia de La Cruz, Wolfgang Kram, Filipe Mergulhao, Rui L Reis, Ilya Skovorodkin, Federico Soria, Seppo Vainio, Shaokai Zheng
Many pathogenic pathways depend on an insufficient or, to the contrary, excessive production of certain proteins [32]. More recently, antisense strategies were explored to address cancer, infectious diseases, chronic inflammatory diseases, and metabolic conditions [33]. Antisense technology is a method that interferes with protein production. It can therefore be used in diseases in which the over- or underproduction of a specific protein plays a crucial role. The principle is that an antisense nucleic acid sequence base pairs with its complementary sense RNA strand and prevents it from being translated into a protein [32] or interferes with its functional aspects [34]. Being a target-specific approach, it is highly attractive for treating underlying molecular disease pathways [33].