Sensitivity enhancement of microelectromechanical sensors using femtosecond laser for biological and chemical applications

Rapid, selective, and highly sensitive microelectromechanical sensors are a promising technology for biosensing, medical recognition, and the detection of chemical hazards. At the same time, the surfaces of silicon microcantilevers cannot bond with thiols and cannot be functionalized without a bonding layer, such as gold. Therefore, in past literature, the surfaces of silicon microcantilevers have been coated with gold to facilitate their bonding with the thiol functional groups on the probe layers. However, gold coating produces thermal noise in the results owing to the metallic effect. Accordingly, this study aimed to modify the surface of silicon microcantilevers by patterning it using femtosecond laser (FSL) micromachining so that it could bond with the thiol functional groups with high sensitivity. The surface patterning of silicon microcantilevers enhances their physical, micromechanical, and chemical properties, increasing sensitivity by increasing the quality factor, specific surface area, and creating trapping areas on the microcantilever surfaces. The surfaces of the silicon microcantilever were patterned by microgrooves aligned from the free end to the bounded end, with each microgroove comprising submicrogrooves. To demonstrate their use in a biosensing applications, the modified microcantilevers were functionalized to detect severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2;COVID-19) by immobilizing thiolated oligonucleotides on the surfaces, which worked as the probe layer. The modified biosensor was used to detect low concentrations of SSDNA sequence targets ranging from 300 nM down to 100 pM. The modified silicon-microcantilever sensors were directly functionalized without a joining layer, such as a gold layer. The results revealed a selective response to SARS-CoV-2 SSDNA down to a 9-nM concentration. To detect hazardous chemicals, the modified microcantilever was functionalized using reduced L-cysteine to detect Pb2+ at low concentrations down to 100 pM. The results revealed enhanced sensitivity and selectivity and demonstrated that the FSL patterning activated the microcantilevers to bond with probe layers through the interaction of the silanol created on the surface with the functional groups, such as the thiols, on the probe layers. The microcantilevers patterned with 10 microgrooves exhibited higher responses than those patterned with seven microgrooves. © 2022 John Wiley & Sons Ltd.

A comprehensive review of the therapeutic potential of curcumin nanoformulations.

Today, due to the prevalence of various diseases such as the novel coronavirus (SARS-CoV-2), diabetes, central nervous system diseases, cancer, cardiovascular disorders, and so on, extensive studies have been conducted on therapeutic properties of natural and synthetic agents. A literature review on herbal medicine and commercial products in the global market showed that curcumin (Cur) has many therapeutic benefits compared to other natural ingredients. Despite the unique properties of Cur, its use in clinical trials is very limited. The poor biopharmaceutical properties of Cur such as short half-life in plasma, low bioavailability, poor absorption, rapid metabolism, very low solubility (at acidic and physiological pH), and the chemical instability in body fluids are major concerns associated with the clinical applications of Cur. Recently, nanoformulations are emerging as approaches to develop and improve the therapeutic efficacy of various drugs. Many studies have shown that Cur nanoformulations have tremendous therapeutic potential against various diseases such as SARS-CoV-2, cancer, inflammatory, osteoporosis, and so on. These nanoformulations can inhibit many diseases through several cellular and molecular mechanisms. However, successful long-term clinical results are required to confirm their safety and clinical efficacy. The present review aims to update and explain the therapeutic potential of Cur nanoformulations.

Novel Synthetic Routes to Prepare Biologically Active Quinoxalines and Their Derivatives: A Synthetic Review for the Last Two Decades.

Quinoxalines, a class of N-heterocyclic compounds, are important biological agents, and a significant amount of research activity has been directed towards this class. They have several prominent pharmacological effects like antifungal, antibacterial, antiviral, and antimicrobial. Quinoxaline derivatives have diverse therapeutic uses and have become the crucial component in drugs used to treat cancerous cells, AIDS, plant viruses, schizophrenia, certifying them a great future in medicinal chemistry. Due to the current pandemic situation caused by SARS-COVID 19, it has become essential to synthesize drugs to combat deadly pathogens (bacteria, fungi, viruses) for now and near future. Since quinoxalines is an essential moiety to treat infectious diseases, numerous synthetic routes have been developed by researchers, with a prime focus on green chemistry and cost-effective methods. This review paper highlights the various synthetic routes to prepare quinoxaline and its derivatives, covering the literature for the last two decades. A total of 31 schemes have been explained using the green chemistry approach, cost-effective methods, and quinoxaline derivatives' therapeutic uses.

Quinoxaline Derivatives as Antiviral Agents: A Systematic Review.

BACKGROUND: In recent decades, several viruses have jumped from animals to humans, triggering sizable outbreaks. The current unprecedent outbreak SARS-COV-2 is prompting a search for new cost-effective therapies to combat this deadly pathogen. Suitably functionalized polysubstituted quinoxalines show very interesting biological properties (antiviral, anticancer, and antileishmanial), ensuring them a bright future in medicinal chemistry. OBJECTIVES: Focusing on the promising development of new quinoxaline derivatives as antiviral drugs, this review forms part of our program on the anti-infectious activity of quinoxaline derivatives. METHODS: Study compiles and discusses recently published studies concerning the therapeutic potential of the antiviral activity of quinoxaline derivatives, covering the literature between 2010 and 2020. RESULTS: A final total of 20 studies included in this review. CONCLUSIONS: This review points to a growing interest in the development of compounds bearing a quinoxaline moiety for antiviral treatment. This promising moiety with different molecular targets warrants further investigation, which may well yield even more encouraging results regarding this scaffold.

RPINBASE: An online toolbox to extract features for predicting RNA-protein interactions.

Feature extraction is one of the most important preprocessing steps in predicting the interactions between RNAs and proteins by applying machine learning approaches. Despite many efforts in this area, still, no suitable structural feature extraction tool has been designed. Therefore, an online toolbox, named RPINBASE which can be applied to different scopes of biological applications, is introduced in this paper. This toolbox employs efficient nested queries that enhance the speed of the requests and produces desired features in the form of positive and negative samples. To show the capabilities of the proposed toolbox, the developed toolbox was investigated in the aptamer design problem, and the obtained results are discussed. RPINBASE is an online toolbox and is accessible at http://rpinbase.com.