Tetrahedral DNA framework assisted rotational paper-based analytical device for differential detection of SARS-CoV-2 and influenza A H1N1 virus

A simple manually rotated paper-based analytical device with electrochemical sensors for the determination of nitrite and nitrate

A user-friendly, rotational paper-based device integrating electrochemical sensors is presented. This innovative device accurately determines nitrite and nitrate ions. Its circular design facilitates the simultaneous detection of both ions. The rotational analytical platform consists of a paper disc that accommodates samples introduced via plastic pipettes. The front side of the disc contains the electrochemical sensors, while the back features a pattern for sample loading. These sensors are specifically designed to detect nitrite and nitrate ions in the sample. Nitrite is determined directly at a working potential of +0.6 V, whereas nitrate is measured after its reduction to nitrite using zinc dust. Moreover, the sensing electrodes are screen-printed carbon electrodes modified with N-doped multiwalled carbon nanotubes (N-MWCNTs) and copper(II) phthalocyanine (CuPc) to enhance sensitivity for nitrite oxidation. This simple device provides a linear range of 50-1000 μM for the simultaneous determination of nitrite and nitrate ions, with detection limits of 10.0 and 20.0 μM, respectively. Furthermore, a manually rotated acrylic plate is employed during sample preparation to facilitate the reduction of nitrate to nitrite. The analytical protocol has been successfully applied to meat samples, and this integrated, portable device shows great potential for rapid, on-site determination of nitrite and nitrate ions in food samples.

Fluorescence origami paper-based analytical device based on strand displacement assay for SARS-CoV-2 cDNA detection

A fluorescence origami paper-based analytical device (Flu-oPAD) based on a strand displacement assay as a point-of-care testing (POCT) sensing platform for DNA detection is presented. This device facilitates multiple steps in a single device, including sample loading, incubation, and washing. The detection zone was immobilized with a 6-FAM-modified probe (F-probe), which formed a complex with a BHQ1-modified probe (Q-probe) to minimize background signals. In the presence of target DNA, hybridization with the F-probe releases the Q-probe, resulting in a fluorescence response proportional to the target DNA concentration. The sensor exhibits good selectivity for target DNA, with a linearity range from 0.1 nM to 10 μM and an experimental detection limit of 0.1 nM, completing all procedures within 15 min. The real-world applicability is demonstrated by successfully detecting complementary DNA (cDNA) from the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), a cause of the COVID-19 pandemic. This study further introduces a multi-array Flu-oPAD for simultaneous detection of SARS-CoV-2 ORF1ab, N, and E gene cDNAs. This multi-array Flu-oPAD is applied to nasopharyngeal swab samples, showing good agreement with the standard RT-PCR method. Overall, the developed Flu-oPAD has shown great potential as an effective POCT tool for DNA screening. It offers simplicity, portability, accessibility, and cost-effectiveness, offering its potential impact on addressing pressing healthcare needs.

Microfluidic Systems: Recent Advances in Chronic Disease Diagnosis and Their Therapeutic Management

Microfluidics has advanced the area of diagnostics during the past ten years by offering fresh approaches that weren't achievable with traditional detection and treatment techniques. High-throughput operations can be carefully controlled by using microfluidics and are very cost-effective too. It has been accepted to be a quick and effective method for controlled medication delivery, biological sample preparation, and analysis. This new technology has made it possible to create a wide range of micro and nanocarriers for poorly soluble medications, which has many advantages over traditional drug delivery techniques. Furthermore, a targeted medication delivery system utilizing microfluidic technology can be developed to enhance the drug's local bioavailability. Over the years, extensive R&D in microfluidic technology has led to the creation of various advanced applications in both laboratory and consumer biotechnology. Miniaturized genetic and proteasome analyzers, cell culture and control platforms, biosensors, disease detection, optical imaging devices, diagnostic advanced drugs, drug delivery schemes, and innovative products are some of the advanced applications of the microfluidics system. Also, these are highly adaptable microfluidic tools for disease detection and organ modeling, as well as transduction devices used in biomedical applications to detect biological and chemical changes. Beyond the specialized difficulties in studying cell-cell interactions, microfluidics has several difficulties in biomedical applications, especially for diagnostic devices where minute interactions can lead to imprecise evaluations. Assay function can be significantly changed by the way plastics, adhesives, and other materials interact. Therefore, the foundation of microfluidic technology needs to be grounded in real-world uses that can be produced on a big scale and at a reasonable cost. Further, it is a very interdisciplinary field that requires the collaboration of professionals in fluidics, assay science, materials science, and instrumentation to provide devices with the proper and needed functionality. In this article, we have discussed the advanced disease diagnosis and their therapeutic management which will help to understand the current scenario in the field of microfluidics diagnosis and will fill knowledge about the 'gap' in the system.

Aptamers and Nanobodies as New Bioprobes for SARS-CoV-2 Diagnostic and Therapeutic System Applications

The global challenges posed by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) pandemic have underscored the critical importance of innovative and efficient control systems for addressing future pandemics. The most effective way to control the pandemic is to rapidly suppress the spread of the virus through early detection using a rapid, accurate, and easy-to-use diagnostic platform. In biosensors that use bioprobes, the binding affinity of molecular recognition elements (MREs) is the primary factor determining the dynamic range of the sensing platform. Furthermore, the sensitivity relies mainly on bioprobe quality with sufficient functionality. This comprehensive review investigates aptamers and nanobodies recently developed as advanced MREs for SARS-CoV-2 diagnostic and therapeutic applications. These bioprobes might be integrated into organic bioelectronic materials and devices, with promising enhanced sensitivity and specificity. This review offers valuable insights into advancing biosensing technologies for infectious disease diagnosis and treatment using aptamers and nanobodies as new bioprobes.

Microfluidic systems for infectious disease diagnostics

Microorganisms, encompassing both uni- and multicellular entities, exhibit remarkable diversity as omnipresent life forms in nature. They play a pivotal role by supplying essential components for sustaining biological processes across diverse ecosystems, including higher host organisms. The complex interactions within the human gut microbiota are crucial for metabolic functions, immune responses, and biochemical signalling, particularly through the gut-brain axis. Viruses also play important roles in biological processes, for example by increasing genetic diversity through horizontal gene transfer when replicating inside living cells. On the other hand, infection of the human body by microbiological agents may lead to severe physiological disorders and diseases. Infectious diseases pose a significant burden on global healthcare systems, characterized by substantial variations in the epidemiological landscape. Fast spreading antibiotic resistance or uncontrolled outbreaks of communicable diseases are major challenges at present. Furthermore, delivering field-proven point-of-care diagnostic tools to the most severely affected populations in low-resource settings is particularly important and challenging. New paradigms and technological approaches enabling rapid and informed disease management need to be implemented. In this respect, infectious disease diagnostics taking advantage of microfluidic systems combined with integrated biosensor-based pathogen detection offers a host of innovative and promising solutions. In this review, we aim to outline recent activities and progress in the development of microfluidic diagnostic tools. Our literature research mainly covers the last 5 years. We will follow a classification scheme based on the human body systems primarily involved at the clinical level or on specific pathogen transmission modes. Important diseases, such as tuberculosis and malaria, will be addressed more extensively.

Biomedical applications of aptamer-modified chitosan nanomaterials: An updated review

Among polysaccharides of environmental and economic interest, chitosan (CS) is receiving much attention, particularly in the food and biotechnology industries to encapsulate active food ingredients and immobilize enzymes. CS nanoparticles (CS NPs) combine the intrinsic beneficial properties of both natural polymers and nanoscale particles such as quantum size effect, biocompatibility, biodegradability, and ease of modification, and have great potential for bioimaging, drug delivery, and biosensing applications. Aptamers are single-stranded oligonucleotides that can fold into predetermined structures and bind to the corresponding biomolecules. They are mainly used as targeting ligands in biosensors, disease diagnostic kits and treatment strategies. They can deliver contrast agents and drugs into cancer cells and tissues, control microorganism growth and precisely target pathogens. Aptamer-conjugated CS NPs can significantly improve the efficacy of conventional therapies, minimize their side effects on normal tissues, and overcome the enhanced permeability retention (EPR) effect. Further, aptamer-conjugated carbohydrate-based nanobiopolymers have shown excellent antibacterial and antiviral properties and can be used to develop novel biosensors for the efficient detection of antibiotics, toxins, and other biomolecules. This updated review aims to provide a comprehensive overview of the bioapplications of aptamer-conjugated CS NPs used as innovative diagnostic and therapeutic platforms, their limitations, and potential future directions.