Selection of DNA aptamers against Mycobacterium tuberculosis Ag85A, and its application in a graphene oxide-based fluorometric assay

The use of nanoparticles in the treatment of infectious diseases and cancer, dental applications and tissue regeneration: a review

The emergence of nanotechnology as a field of study can be traced back to the 1980s, at which point the means to artificially produce, control, and observe matter on a nanometer level was made viable. Recent advancements in technology have enabled us to extend our reach to the nanoscale, which has presented an unparalleled opportunity to directly target biomolecular interactions. As a result of these developments, there is a drive to arise intelligent nanostructures capable of overcoming the obstacles that have impeded the progress of conventional pharmacological methodologies. After four decades, the gradual amalgamation of bio- and nanotechnologies is initiating a revolution in the realm of disease detection, treatment, and monitoring, as well as unsolved medical predicaments. Although a significant portion of research in the field is still confined to laboratories, the initial application of nanotechnology as treatments, vaccines, pharmaceuticals, and diagnostic equipment has now obtained endorsement for commercialization and clinical practice. The current issue presents an overview of the latest progress in nanomedical strategies towards alleviating antibiotic resistance, diagnosing and treating cancer, addressing neurodegenerative disorders, and an array of applications, encompassing dentistry and tuberculosis treatment. The current investigation also scrutinizes the deployment of sophisticated smart nanostructured materials in fields of application such as regenerative medicine, as well as the management of targeted and sustained release of pharmaceuticals and therapeutic interventions. The aforementioned concept exhibits the potential for revolutionary advancements within the field of immunotherapy, as it introduces the utilization of implanted vaccine technology to consistently regulate and augment immune functions. Concurrently with the endeavor to attain the advantages of nanomedical intervention, it is essential to enhance the unceasing emphasis on nanotoxicological research and the regulation of nanomedications' safety. This initiative is crucial in achieving the advancement in medicine that currently lies within our reach.

Nano-Delivery System of Ethanolic Extract of Propolis Targeting Mycobacterium tuberculosis via Aptamer-Modified-Niosomes

Tuberculosis (TB) therapy requires long-course multidrug regimens leading to the emergence of drug-resistant TB and increased public health burden worldwide. As the treatment strategy is more challenging, seeking a potent non-antibiotic agent has been raised. Propolis serve as a natural source of bioactive molecules. It has been evidenced to eliminate various microbial pathogens including Mycobacterium tuberculosis (Mtb). In this study, we fabricated the niosome-based drug delivery platform for ethanolic extract of propolis (EEP) using thin film hydration method with Ag85A aptamer surface modification (Apt-PEGNio/EEP) to target Mtb. Physicochemical characterization of PEGNio/EEP indicated approximately -20 mV of zeta potential, 180 nm of spherical nanoparticles, 80% of entrapment efficiency, and the sustained release profile. The Apt-PEGNio/EEP and PEGNio/EEP showed no difference in these characteristics. The chemical composition in the nanostructure was confirmed by Fourier transform infrared spectrometry. Apt-PEGNio/EEP showed specific binding to Mycobacterium expressing Ag85 membrane-bound protein by confocal laser scanning microscope. It strongly inhibited Mtb in vitro and exhibited non-toxicity on alveolar macrophages. These findings indicate that the Apt-PEGNio/EEP acts as an antimycobacterial nanoparticle and might be a promising innovative targeted treatment. Further application of this smart nano-delivery system will lead to effective TB management.

Simultaneous Amperometric Aptasensor Based on Diazonium Grafted Screen-Printed Carbon Electrode for Detection of CFP10 and MPT64 Biomarkers for Early Tuberculosis Diagnosis

Early diagnosis is highly crucial for life-saving and transmission management of tuberculosis (TB). Despite the low sensitivity and time-consuming issues, TB antigen detection still relies on conventional smear microscopy and culture techniques. To address this limitation, we report the development of the first amperometric dual aptasensor for the simultaneous detection of Mycobacterium tuberculosis secreted antigens CFP10 and MPT64 for better diagnosis and control of TB. The developed sensor was based on the aptamers-antibodies sandwich assay and detected by chronoamperometry through the electrocatalytic reaction between peroxidase-conjugated antibodies, H₂O₂, and hydroquinone. The CFP10 and MPT64 aptamers were immobilized via carbodiimide covalent chemistry over the disposable dual screen-printed carbon electrodes modified with a 4-carboxyphenyl diazonium salt. Under optimized conditions, the aptasensor achieved a detection limit of 1.68 ng mL^-1 and 1.82 ng mL^-1 for CFP10 and MPT64 antigens, respectively. The developed assay requires a small sample amount (5 µL) and can be easily performed within 2.5 h. Finally, the dual aptasensor was successfully applied to clinical sputum samples with the obtained diagnostic sensitivity (n = 24) and specificity (n = 13) of 100%, respectively, suggesting the readiness of the developed assay to be used for TB clinical application.

Graphene oxide-based fluorescent biosensors and their biomedical applications in diagnosis and drug discovery

Graphene oxide (GO), an oxidized derivative of graphene, has received much attention for developing novel fluorescent bioanalytic platforms due to its remarkable optical properties and biocompatibility. The reliable performance and robustness of GO-based biosensors have enabled various applications in the biomedical field including diagnosis and drug discovery. Here, recent advances in the development of GO-based fluorescent biosensors are overviewed, particularly nucleic acid detection and enzyme activity assay. In addition, practical applications in biomarker detection and high-throughput screening are also examined. Lastly, basic design principles and remaining challenges of these types of biosensors are discussed for further progress.

Aptasensor for the Detection of Mycobacterium tuberculosis in Sputum Utilising CFP10-ESAT6 Protein as a Selective Biomarker

A portable electrochemical aptamer-antibody based sandwich biosensor has been designed and successfully developed using an aptamer bioreceptor immobilized onto a screen-printed electrode surface for Mycobacterium tuberculosis (M. tuberculosis) detection in clinical sputum samples. In the sensing strategy, a CFP10-ESAT6 binding aptamer was immobilized onto a graphene/polyaniline (GP/PANI)-modified gold working electrode by covalent binding via glutaraldehyde linkage. Upon interaction with the CFP10-ESAT6 antigen target, the aptamer will capture the target where the nano-labelled Fe3O4/Au MNPs conjugated antibody is used to complete the sandwich format and enhance the signal produced from the aptamer-antigen interaction. Using this strategy, the detection of CFP10-ESAT6 antigen was conducted in the concentration range of 5 to 500 ng/mL. From the analysis, the detection limit was found to be 1.5 ng/mL, thereby demonstrating the efficiency of the aptamer as a bioreceptor. The specificity study was carried out using bovine serum albumin (BSA), MPT64, and human serum, and the result demonstrated good specificity that is 7% higher than the antibody-antigen interaction reported in a previous study. The fabricated aptasensor for M. tuberculosis analysis shows good reproducibility with an relative standard deviation (RSD) of 2.5%. Further analysis of M. tuberculosis in sputum samples have shown good correlation with the culture method with 100% specificity and sensitivity, thus making the aptasensor a promising candidate for M. tuberculosis detection considering its high specificity and sensitivity with clinical samples.

Systematic Evolution of Ligands by Exponential Enrichment Technologies and Aptamer-Based Applications: Recent Progress and Challenges in Precision Medicine of Infectious Diseases

Infectious diseases are considered as a pressing challenge to global public health. Accurate and rapid diagnostics tools for early recognition of the pathogen, as well as individualized precision therapy are essential for controlling the spread of infectious diseases. Aptamers, which were screened by systematic evolution of ligands by exponential enrichment (SELEX), can bind to targets with high affinity and specificity so that have exciting potential in both diagnosis and treatment of infectious diseases. In this review, we provide a comprehensive overview of the latest development of SELEX technology and focus on the applications of aptamer-based technologies in infectious diseases, such as targeted drug-delivery, treatments and biosensors for diagnosing. The challenges and the future development in this field of clinical application will also be discussed.

Oligonucleotide aptamers for pathogen detection and infectious disease control

During an epidemic or pandemic, the primary task is to rapidly develop precise diagnostic approaches and effective therapeutics. Oligonucleotide aptamer-based pathogen detection assays and control therapeutics are promising, as aptamers that specifically recognize and block pathogens can be quickly developed and produced through simple chemical synthesis. This work reviews common aptamer-based diagnostic techniques for communicable diseases and summarizes currently available aptamers that target various pathogens, including the SARS-CoV-2 virus. Moreover, this review discusses how oligonucleotide aptamers might be leveraged to control pathogen propagation and improve host immune system responses. This review offers a comprehensive data source to the further develop aptamer-based diagnostics and therapeutics specific for infectious diseases.

Application of the catalytic activity of gold nanoparticles for development of optical aptasensors

Biosensor technology is considered to be a great alternative in analytical techniques over the conventional methods. Among many recently developed techniques and devices, aptasensors are interesting because of their high specificity, selectivity and sensitivity. Combining aptamer as a biological recognition element with gold nanoparticles (AuNPs) as probe, are becoming more general owing to their beneficial properties, including low cost and ability to analyze specific targets on-site and using naked eye. Hydrogen bonds, nucleic acid hybridization, aptamer-target and antigen-antibody binding, Raman signature, enzyme inhibition, and enzyme-mimicking activity are main different sensing strategies exploited in AuNPs-based optical aptasensors. In this review article, we discussed the recent advances in optical aptasensors with a special emphasis on the catalytic activity property of AuNPs.

Aptamers: An Emerging Tool for Diagnosis and Therapeutics in Tuberculosis

Tuberculosis (TB) has been plaguing human civilization for centuries, and currently around one-third of the global population is affected with TB. Development of novel intervention tools for early diagnosis and therapeutics against Mycobacterium tuberculosis (M.tb) is the main thrust area in today's scenario. In this direction global efforts were made to use aptamers, the chemical antibodies as tool for TB diagnostics and therapeutics. This review describes the various aptamers introduced for targeting M.tb and highlights the need for development of novel aptamers to selectively target virulent proteins of M.tb for vaccine and anti-TB drugs. The objective of this review is to highlight the diagnostic and therapeutic application of aptamers used for tuberculosis. The discovery of aptamers, SELEX technology, different types of SELEX development processes, DNA and RNA aptamers reported for diseases and pathogenic agents as well have also been described in detail. But the emphasis of this review is on the development of aptamers which can block the function of virulent mycobacterial components for developing newer TB vaccine candidates and/or drug targets. Aptamers designed to target M.tb cell wall proteins, virulent factors, secretory proteins, or combination could orchestrate advanced diagnosis and therapeutic measures for tuberculosis.

Graphene biosensors for bacterial and viral pathogens

The infection and spread of pathogens (e.g., COVID-19) pose an enormous threat to the safety of human beings and animals all over the world. The rapid and accurate monitoring and determination of pathogens are of great significance to clinical diagnosis, food safety and environmental evaluation. In recent years, with the evolution of nanotechnology, nano-sized graphene and graphene derivatives have been frequently introduced into the construction of biosensors due to their unique physicochemical properties and biocompatibility. The combination of biomolecules with specific recognition capabilities and graphene materials provides a promising strategy to construct more stable and sensitive biosensors for the detection of pathogens. This review tracks the development of graphene biosensors for the detection of bacterial and viral pathogens, mainly including the preparation of graphene biosensors and their working mechanism. The challenges involved in this field have been discussed, and the perspective for further development has been put forward, aiming to promote the development of pathogens sensing and the contribution to epidemic prevention.

Recent progress and challenges on the bioassay of pathogenic bacteria

The present review (containing 242 references) illustrates the importance and application of optical and electrochemical methods as well as their performance improvement using various methods for the detection of pathogenic bacteria. The application of advanced nanomaterials including hyper branched nanopolymers, carbon-based materials and silver, gold and so on. nanoparticles for biosensing of pathogenic bacteria was also investigated. In addition, a summary of the applications of nanoparticle-based electrochemical biosensors for the identification of pathogenic bacteria has been provided and their advantages, detriments and future development capabilities was argued. Therefore, the main focus in the present review is to investigate the role of nanomaterials in the development of biosensors for the detection of pathogenic bacteria. In addition, type of nanoparticles, analytes, methods of detection and injection, sensitivity, matrix and method of tagging are also argued in detail. As a result, we have collected electrochemical and optical biosensors designed to detect pathogenic bacteria, and argued outstanding features, research opportunities, potential and prospects for their development, according to recently published research articles.

Recent Progress in the Identification of Aptamers Against Bacterial Origins and Their Diagnostic Applications

Aptamers have gained an increasing role as the molecular recognition element (MRE) in diagnostic assay development, since their first conception thirty years ago. The process to screen for nucleic acid-based binding elements (aptamers) was first described in 1990 by the Gold Laboratory. In the last three decades, many aptamers have been identified for a wide array of targets. In particular, the number of reports on investigating single-stranded DNA (ssDNA) aptamer applications in biosensing and diagnostic platforms have increased significantly in recent years. This review article summarizes the recent (2015 to 2020) progress of ssDNA aptamer research on bacteria, proteins, and lipids of bacterial origins that have implications for human infections. The basic process of aptamer selection, the principles of aptamer-based biosensors, and future perspectives will also be discussed.

Recent Developments in the Application of Flow Cytometry to Advance our Understanding of Mycobacterium tuberculosis Physiology and Pathogenesis

The ability of the bacterial pathogen Mycobacterium tuberculosis to adapt and survive within human cells to disseminate to other individuals and cause active disease is poorly understood. Research supports that as M. tuberculosis adapts to stressors encountered in the host, it exhibits variable physiological and metabolic states that are time and niche-dependent. Challenges associated with effective treatment and eradication of tuberculosis (TB) are in part attributed to our lack of understanding of these different mycobacterial phenotypes. This is mainly due to a lack of suitable tools to effectively identify/detect heterogeneous bacterial populations, which may include small, difficult-to-culture subpopulations. Importantly, flow cytometry allows rapid and affordable multiparametric measurements of physical and chemical characteristics of single cells, without the need to preculture cells. Here, we summarize current knowledge of flow cytometry applications that have advanced our understanding of the physiology of M. tuberculosis during TB disease. Specifically, we review how host-associated stressors influence bacterial characteristics such as metabolic activity, membrane potential, redox status and the mycobacterial cell wall. Further, we highlight that flow cytometry offers unprecedented opportunities for insight into bacterial population heterogeneity, which is increasingly appreciated as an important determinant of disease outcome. © 2020 The Authors. Cytometry Part A published by Wiley Periodicals, Inc. on behalf of International Society for Advancement of Cytometry.