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Topic review
Updated time: 01 Nov 2020
Submitted by: Yi-Kuang Yen
Definition: A graphene and poly (3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) modified conductive paper-based electrochemical impedance spectroscopy (EIS) aptasensor has been successfully fabricated by a simple and continuous coating process. A graphene/PEDOT:PSS modified paper electrode forms the nanocomposite providing a conductive and sensitive substrate for further aptamer functionalization of the biosensor. This low-cost paper-based aptasensor exhibits its sensitivity to carcinoembryonic antigens (CEA) in standard buffer solutions and human serum samples in a linear range of 0.77–14 ng·mL−1. The limit of detection (LOD) is found to be 0.45 ng·mL−1and 1.06 ng·mL−1for CEA in both samples, separately. This aptamer-based sensing device was also evaluated and received a good correlation with the immunoassay detection method. The proposed paper-based aptasensor has demonstrated its potential as a rapid simple point-of-care analytical platform for early cancer diagnosis in less developed areas where manufacturing facilities, analytical instruments, and trained specialists are limited.
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Topic review
Updated time: 18 Jan 2021
Submitted by: Gregor Marolt
Definition: Phytate is a six-fold dihydrogenphosphate ester of myo‑inositol or cis-1,2,3,5-trans-4,6-cyclohexanehexol which is the most abundant of nine possible isomers of inositol (Ins). Myo-orientation is also found in the case of phytic acid, which is due to the fact that the maximal number (i.e., five out of six) of phosphate groups are present in thermodynamically stabilized equatorial position. However, the molecule can be inverted from equatorial (1a5e) to the axial (5a1e) orientation between pH 9.0 and pH 9.5.
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Topic review
Updated time: 11 Mar 2021
Submitted by: Rimadani Pratiwi
Definition: Codeine is derived from morphine, an opioid analgesic, and has weaker analgesic and sedative effects than the parent molecule. This weak opioid is commonly used in combination with other drugs for over-the-counter cough relief medication. Due to the psychoactive properties of opioid drugs, the easily obtained codeine often becomes subject to misuse. Codeine misuse has emerged as a concerning public health issue due to its associated adverse effects such as headache, nausea, vomiting, and hemorrhage. Thus, it is very important to develop reliable analytical techniques to detect codeine for both quality control of pharmaceutical formulations and identifying drug misuse in the community. This review aims to provide critical outlooks on analytical methods napplicable to the determination of codeine.
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Topic review
Updated time: 15 Dec 2020
Submitted by: Nurhasliza Zolkefli
Definition: Researchers are continuously rallying to enhance the detection of causal source for water pollution through either conventional or mostly advanced approaches focusing on spectrometry, high-throughput sequencing, and flow cytometry technology among others. From this review’s perspective, each pollution evaluation technology has its own advantages and it would be beneficial for several aspects of pollutants assessments to be combined and established as a complementary package for a better aquatic environmental management in the long run.
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Topic review
Updated time: 30 Apr 2021
Submitted by: Anurag Malik
Definition: All the research pertaining to the detection and identification of minute peptides (<4 amino acids) present in multifarious mixtures are in their early stages because of a lack of stringent peptide identification methodologies. Precise amendments like discerned censoring of ions against previously identified sequences of peptides can help overcome the aforementioned issues faced at times of optimization procedures during or after MS analysis. A state-of-the-art genesis in structure-informedpeptide identification and quantification methodologies can be guaranteed by added enrichment in the sensitivity and resolving capacity of MS, in conjunction with novel cutting edge ionization techniques. Modernization of the software for foodomics and peptidomics research and peptide identification is needed. Also, explicit and coherent structure identification in common and especially in synchronization with LC-MS requires significant attention. A continuous focus will be given to understanding of the biochemical functions of milk ingredients and their dietary implications by using a variety of powerful tools like -omics, cell models, gut microbiome research and imaging. The introduction of innovative facilities including is an absolute requirement for the development of approaches, such as proteomics, recombinant enzymes and microbial fermentation to study and improve the metabolic and health consequences of the various roles of bioactive peptides throughout the expression of genes. Consequently, the formulation of products incorporating bioactive peptides should examine the allergenicity, toxicity and stability of the a ected metabolic functions during gastrointestinal digestion. Despite considerable progress in the isolation, purification and assessment of bioactivities of BP from various natural sources, several hurdles still remain to be overcome, particularly technological advancements to produce them on a broad scale without losing activity. In conclusion, milk-derived bioactive peptides o er substantial future prospects for product development to support health, with their multifunctional assets.
Topic review
Updated time: 20 Oct 2020
Submitted by: Michael Schoening
Definition: Electrolyte-insulator-semiconductor (EIS) field-effect sensors belong to a new generation of electronic chips for biochemical sensing, enabling a direct electronic readout. The review gives an overview on recent advances and current trends in the research and development of chemical sensors and biosensors based on the capacitive field-effect EIS structure—the simplest field-effect device, which represents a biochemically sensitive capacitor. Fundamental concepts, physicochemical phenomena underlying the transduction mechanism and application of capacitive EIS sensors for the detection of pH, ion concentrations, and enzymatic reactions, as well as the label-free detection of charged molecules (nucleic acids, proteins, and polyelectrolytes) and nanoparticles, are presented and discussed.
Topic review
Updated time: 24 Jul 2020
Submitted by: Sammer-ul Hassan
Definition: Point-of-care (POC) or near-patient testing allows clinicians to accurately achieve real-time diagnostic results performed at or near to the patient site. The outlook of POC devices is to provide quicker analyses that can lead to well-informed clinical decisions and hence improve the health of patients at the point-of-need. Microfluidics plays an important role in the development of POC devices. However, requirements of handling expertise, pumping systems and complex fluidic controls make the technology unaffordable to the current healthcare systems in the world. In recent years, capillary-driven flow microfluidics has emerged as an attractive microfluidic-based technology to overcome these limitations by offering robust, cost-effective and simple-to-operate devices. The internal wall of the microchannels can be pre-coated with reagents, and by merely dipping the device into the patient sample, the sample can be loaded into the microchannel driven by capillary forces and can be detected via handheld or smartphone-based detectors. The capabilities of capillary-driven flow devices have not been fully exploited in developing POC diagnostics, especially for antimicrobial resistance studies in clinical settings. The purpose of this review is to open up this field of microfluidics to the ever-expanding microfluidic-based scientific community.
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Topic review Peer-reviewed
Updated time: 27 Jan 2021
Submitted by: Anastasios Zouboulis
Definition: Catalytic membrane ozonation is a hybrid process that combines membrane filtration and catalytic ozonation. The membrane deposited with an appropriate solid material acts as catalyst. As a consequence, the catalytic membrane contactor can act simultaneously as contactor (i.e., improving the transfer/dissolution of gaseous ozone into the liquid phase), as well as reactor (i.e., oxidizing the organic compounds). It can be used in water and wastewater treatment limiting the disadvantages of membrane filtration (i.e., lower removal rates of emerging contaminants or fouling occurrence) and ozonation (i.e., selective oxidation, low mineralization rates, or bromate (BrO3−) formation). The catalytic membrane ozonation process can enhance the removal of micropollutants and bacteria, inhibit or decrease the BrO3− formation and additionally, restrict the membrane fouling (i.e., the major/common problem of membranes’ use). Nevertheless, the higher operational cost is the main drawback of these processes.
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Topic review
Updated time: 11 Jan 2021
Definition: With comparison to cellulose and hemicelluloses, lignin is generally less prone to most degradation processes affecting archaeological artefacts in burial environments, especially waterlogged ones, which are the most favourable for wood preservation. Nevertheless, lignin also undergoes significant chemical changes. As wood from waterlogged environments is mainly composed of lignin, knowledge of its chemical structure and degradation pathways is fundamental for choosing preventive conservation conditions and for optimising consolidation methods and materials, which directly interact with the residual lignin. Analytical pyrolysis coupled with mass spectrometry, used in several complementary operational modes, can gather information regarding the chemical modifications and the state of preservation of lignin, especially concerning oxidation and depolymerisation phenomena. Several applications to the analysis of wood from archaeological artefacts affected by different conservation problems are presented to showcase the potential of analytical pyrolysis in various scenarios that can be encountered when investigating archaeological waterlogged wood.
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Topic review
Updated time: 24 Nov 2020
Submitted by: Wei Chen
Definition: Using renewable energy to convert CO2 to a clean fuel ethanol can not only reduce carbon emission by the utilization of CO2 as feedstock, but also store renewable energy as the widely used chemical and high-energy-density fuel, being considered as a perfect strategy to address current environment and energy issues. Developing efficient electrocatalysts, photocatalysts, and photoelectrocatalysts for CO2 reduction is the most crucial keystone for achieving this goal. Considerable progresses in CO2-based ethanol production have been made over the past decades. This review provides the general principles and summarizes the latest advancements of electrocatalytic, photocatalytic and photoelectrocatalytic CO2 conversion to ethanol. Furthermore, the main challenges and proposed future prospects are illustrated for further development of the clean fuel ethanol production.
Entry Collection : Chemical Bond
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