Nanomaterials Connected to Bioreceptors to Introduce Efficient Biosensing Strategy for Diagnosis of the TORCH Infections: A Critical Review

TORCH infection is a significant risk factor for severe fetal damage, especially congenital malformations. Screening pregnant women for TORCH pathogens could reduce the incidence of adverse pregnancy outcomes and prevent birth defects. Hence, timely identification and inhibition of TORCH infections are effective ways to successfully prevent them in pregnant women. Recently, the superiority of biosensors in TORCH pathogen sensing has been emphasized due to their intrinsic benefits, such as rapid response time, portability, cost-effectiveness, much friendlier preparation and determination steps. With the introduction of advanced nanomaterials into biosensing, the diagnostic properties of biosensors have significantly improved. This study core presents and debates the current progress in biosensing systems for TORCH pathogens using various artificial and natural receptors. The incorporation of nanomaterials into various transduction systems can enhance diagnostic performance. The key performance characteristics of optical and electrochemical biosensors, such as response time, limit of detection (LOD), and linear detection range, are systematically discussed, along with the current TORCH pathogens used for constructing biosensors. Finally, the major problems that exist for converting scientific investigation into product development are also outlined.

Recent Advances in Early Diagnosis of Viruses Associated with Gastroenteritis by Biosensors

Gastroenteritis, as one of the main worldwide health challenges, especially in children, leads to 3-6 million deaths annually and causes nearly 20% of the total deaths of children aged ˂5 years, of which ~1.5 million gastroenteritis deaths occur in developing nations. Viruses are the main causative agent (~70%) of gastroenteritis episodes and their specific and early diagnosis via laboratory assays is very helpful for having successful antiviral therapy and reduction in infection burden. Regarding this importance, the present literature is the first review of updated improvements in the employing of different types of biosensors such as electrochemical, optical, and piezoelectric for sensitive, simple, cheap, rapid, and specific diagnosis of human gastroenteritis viruses. The Introduction section is a general discussion about the importance of viral gastroenteritis, types of viruses that cause gastroenteritis, and reasons for the combination of conventional diagnostic tests with biosensors for fast detection of viruses associated with gastroenteritis. Following the current laboratory detection tests for human gastroenteritis viruses and their limitations (with subsections: Electron Microscope (EM), Cell Culture, Immunoassay, and Molecular Techniques), structural features and significant aspects of various biosensing methods are discussed in the Biosensor section. In the next sections, basic information on viruses causing gastroenteritis and recent developments for fabrication and testing of different biosensors for each virus detection are covered, and the prospect of future developments in designing different biosensing platforms for gastroenteritis virus detection is discussed in the Conclusion and Future Directions section as well.

Optical Biosensors for Diagnostics of Infectious Viral Disease: A Recent Update

The design and development of biosensors, analytical devices used to detect various analytes in different matrices, has emerged. Biosensors indicate a biorecognition element with a physicochemical analyzer or detector, i.e., a transducer. In the present scenario, various types of biosensors have been deployed in healthcare and clinical research, for instance, biosensors for blood glucose monitoring. Pathogenic microbes are contributing mediators of numerous infectious diseases that are becoming extremely serious worldwide. The recent outbreak of COVID-19 is one of the most recent examples of such communal and deadly diseases. In efforts to work towards the efficacious treatment of pathogenic viral contagions, a fast and precise detection method is of the utmost importance in biomedical and healthcare sectors for early diagnostics and timely countermeasures. Among various available sensor systems, optical biosensors offer easy-to-use, fast, portable, handy, multiplexed, direct, real-time, and inexpensive diagnosis with the added advantages of specificity and sensitivity. Many progressive concepts and extremely multidisciplinary approaches, including microelectronics, microelectromechanical systems (MEMSs), nanotechnologies, molecular biology, and biotechnology with chemistry, are used to operate optical biosensors. A portable and handheld optical biosensing device would provide fast and reliable results for the identification and quantitation of pathogenic virus particles in each sample. In the modern day, the integration of intelligent nanomaterials in the developed devices provides much more sensitive and highly advanced sensors that may produce the results in no time and eventually help clinicians and doctors enormously. This review accentuates the existing challenges engaged in converting laboratory research to real-world device applications and optical diagnostics methods for virus infections. The review's background and progress are expected to be insightful to the researchers in the sensor field and facilitate the design and fabrication of optical sensors for life-threatening viruses with broader applicability to any desired pathogens.

Advances in airborne microorganisms detection using biosensors: A critical review

Humanity has been facing the threat of a variety of infectious diseases. Airborne microorganisms can cause airborne infectious diseases, which spread rapidly and extensively, causing huge losses to human society on a global scale. In recent years, the detection technology for airborne microorganisms has developed rapidly; it can be roughly divided into biochemical, immune, and molecular technologies. However, these technologies still have some shortcomings; they are time-consuming and have low sensitivity and poor stability. Most of them need to be used in the ideal environment of a laboratory, which limits their applications. A biosensor is a device that converts biological signals into detectable signals. As an interdisciplinary field, biosensors have successfully introduced a variety of technologies for bio-detection. Given their fast analysis speed, high sensitivity, good portability, strong specificity, and low cost, biosensors have been widely used in environmental monitoring, medical research, food and agricultural safety, military medicine and other fields. In recent years, the performance of biosensors has greatly improved, becoming a promising technology for airborne microorganism detection. This review introduces the detection principle of biosensors from the three aspects of component identification, energy conversion principle, and signal amplification. It also summarizes its research and application in airborne microorganism detection. The new progress and future development trend of the biosensor detection of airborne microorganisms are analyzed.

Optical biosensors: an exhaustive and comprehensive review

Optical biosensors have exhibited worthwhile performance in detecting biological systems and promoting significant advances in clinical diagnostics, drug discovery, food process control, and environmental monitoring. Without complexity in their pretreatment and probable influence on the nature of target molecules, these biosensors have additional advantages such as high sensitivity, robustness, reliability, and potential to be integrated on a single chip. In this review, the state of the art optical biosensor technologies, including those based on surface plasmon resonance (SPR), optical waveguides, optical resonators, photonic crystals, and optical fibers, are presented. The principles for each type of biosensor are concisely introduced and particular emphasis has been placed on recent achievements. The strengths and weaknesses of each type of biosensor have been outlined as well. Concluding remarks regarding the perspectives of future developments are discussed.

Photonic crystal based biosensors: Emerging inverse opals for biomarker detection

Photonic crystal (PC)-based inverse opal (IO) arrays are one of the substrates for label-free sensing mechanism. IO-based materials with their advanced and ordered three-dimensional microporous structures have recently found attractive optical sensor and biological applications in the detection of biomolecules like proteins, DNA, viruses, etc. The unique optical and structural properties of IO materials can simplify the improvements in non-destructive optical study capabilities for point of care testing (POCT) used within a wide variety of biosensor research. In this review, which is an interdisciplinary investigation among nanotechnology, biology, chemistry and medical sciences, the recent fabrication methodologies and the main challenges regarding the application of (inverse opals) IOs in terms of their bio-sensing capability are summarized.

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The recent main challenges regarding the application of inverse opals (IOs) in the detection of biomolecules are reviewed.

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Sensing mechanisms of biomolecules including glucose, proteins, DNA, viruses were summarized.

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IO materials with their ordered 3D microporous structures have found attractive optical biosensor applications.

Multidimensional Conductive Nanofilm-Based Flexible Aptasensor for Ultrasensitive and Selective HBsAg Detection

Hepatitis B virus (HBV) infection is a major worldwide health issue causing serious liver diseases, including liver cirrhosis and hepatocellular carcinoma. Monitoring the serum hepatitis B surface antigen (HBsAg) level is pivotal to the diagnosis of HBV infection. In this study, we describe multidimensional conductive nanofilm (MCNF)-based field-effect transistor (FET) aptasensor for HBsAg detection. The MCNF, composed of vertically oriented carboxylic polypyrrole nanowires (CPPyNW) and graphene layer, is formed using electropolymerization of pyrrole on the graphene surface and following acid treatment. The amine-functionalized HBsAg-binding aptamers are then immobilized on the CPPyNW surface through covalent bonding formation (i.e., amide group). The prepared aptasensor presents highly sensitive to HBsAg as low as 10 aM among interfering biomolecules with various deformations. Moreover, the MCNF-based aptasensor has great potential for practical application in the noninvasive real-time diagnosis because of its improved sensing ability to the human serum and artificial saliva.

An Antibody-Immobilized Silica Inverse Opal Nanostructure for Label-Free Optical Biosensors

Three-dimensional SiO₂-based inverse opal (SiO₂-IO) nanostructures were prepared for use as biosensors. SiO₂-IO was fabricated by vertical deposition and calcination processes. Antibodies were immobilized on the surface of SiO₂-IO using 3-aminopropyl trimethoxysilane (APTMS), a succinimidyl-[(N-maleimidopropionamido)-tetraethyleneglycol] ester (NHS-PEG₄-maleimide) cross-linker, and protein G. The highly accessible surface and porous structure of SiO₂-IO were beneficial for capturing influenza viruses on the antibody-immobilized surfaces. Moreover, as the binding leads to the redshift of the reflectance peak, the influenza virus could be detected by simply monitoring the change in the reflectance spectrum without labeling. SiO₂-IO showed high sensitivity in the range of 10³–10⁵ plaque forming unit (PFU) and high specificity to the influenza A (H1N1) virus. Due to its structural and optical properties, SiO₂-IO is a promising material for the detection of the influenza virus. Our study provides a generalized sensing platform for biohazards as various sensing strategies can be employed through the surface functionalization of three-dimensional nanostructures.

Photonic crystals: emerging biosensors and their promise for point-of-care applications

Biosensors are extensively employed for diagnosing a broad array of diseases and disorders in clinical settings worldwide. The implementation of biosensors at the point-of-care (POC), such as at primary clinics or the bedside, faces impediments because they may require highly trained personnel, have long assay times, large sizes, and high instrumental cost. Thus, there exists a need to develop inexpensive, reliable, user-friendly, and compact biosensing systems at the POC. Biosensors incorporated with photonic crystal (PC) structures hold promise to address many of the aforementioned challenges facing the development of new POC diagnostics. Currently, PC-based biosensors have been employed for detecting a variety of biotargets, such as cells, pathogens, proteins, antibodies, and nucleic acids, with high efficiency and selectivity. In this review, we provide a broad overview of PCs by explaining their structures, fabrication techniques, and sensing principles. Furthermore, we discuss recent applications of PC-based biosensors incorporated with emerging technologies, including telemedicine, flexible and wearable sensing, smart materials and metamaterials. Finally, we discuss current challenges associated with existing biosensors, and provide an outlook for PC-based biosensors and their promise at the POC.

Advances in biosensing strategies for HIV-1 detection, diagnosis, and therapeutic monitoring

HIV-1 is a major global epidemic that requires sophisticated clinical management. There have been remarkable efforts to develop new strategies for detecting and treating HIV-1, as it has been challenging to translate them into resource-limited settings. Significant research efforts have been recently devoted to developing point-of-care (POC) diagnostics that can monitor HIV-1 viral load with high sensitivity by leveraging micro- and nano-scale technologies. These POC devices can be applied to monitoring of antiretroviral therapy, during mother-to-child transmission, and identification of latent HIV-1 reservoirs. In this review, we discuss current challenges in HIV-1 diagnosis and therapy in resource-limited settings and present emerging technologies that aim to address these challenges using innovative solutions.