Aptamer Detection of Mycobaterium tuberculosis Mannose-Capped Lipoarabinomannan in Lesion Tissues for Tuberculosis Diagnosis

Development and assessment of a novel magnetic nanoparticle antibody-conjugate and aptamer-based assay (MNp-Ab-Ap assay) for the rapid diagnosis of pleural tuberculosis

Background: Pleural tuberculosis (pTB) is a diagnostic challenge because of its non-specific clinical features, lack of accurate diagnostic tools and paucibacillary nature of the disease. Methods: We, here describe the development of a novel magnetic nanoparticle antibody-conjugate and aptamer-based assay (MNp-Ab-Ap assay) targeting 4 different Mycobacterium tuberculosis (M. tb.) antigens (GlcB, MPT51, MPT64 and CFP-10) for pTB diagnosis. The MNp-Ab-Ap assay was developed by conjugating polyclonal antibodies on the surface of magnetic nanoparticles (MNPs) by using EDC-NHS chemistry. These conjugated MNPs were used to capture M. tb. antigens present in the pleural fluid samples. The resulting antigen-antibody complex was detected by antigen-specific 5'-biotinylated aptamers. All assays were standardized using samples of the 'Development set' (n=17) and evaluated in the 'Validation set' (n=114) in a blinded manner. Patient categorization was done using a 'Composite Reference Standard'. Assay cut-offs were determined from the 'Development set' (n=17; 'Definite & Probable' pTB; n=9 and 'Non-TB'; n=8) by calculating mean+3SD of OD450 values of the 'Non-TB' group and applied to 'Validation set' (n=114; 'Definite' pTB; n=8, 'Probable' pTB; n=34, 'Possible' pTB; n=28 and 'Non-TB'; n=44). Results: Out of the 4 assays, MPT51-based MNp-Ab-Ap assay performed the best with 66.6% (95%CI;50.4-80.4) sensitivity and 95.4% (95%CI;85.1-99.4) specificity in the combined 'Definite and Probable' pTB group. Xpert MTB/RIF assay detected only six samples in the 'Validation set'. Binary logistic regression analysis indicated that MPT51-based MNp-Ab-Ap assay provided an incremental advantage over the existing diagnostic algorithm for pTB. Conclusions: We conclude that MPT51-based MNp-Ab-Ap assay is a novel technique that can pave the way towards rapid and accurate diagnosis of pTB.

The application of aptamer in tuberculosis diagnosis: a systematic review

Tuberculosis represents a significant menace to health, leading to millions of cases and fatalities each year. Traditional diagnostic methods, while effective, have limitations, necessitating improved tools. Aptamers possessing remarkable specificity single-stranded DNA or RNA molecules promising in TB diagnosis due to their adaptability and precise biomarker detection capabilities. In this study, we aimed to evaluate the research on aptamer applications in TB diagnosis, evaluating the efficacy, limitations, and future prospects. The present systematic review study followed PRISMA guidelines, including peer-reviewed studies on aptamer efficacy in TB diagnosis. Eligibility criteria covered experimental and human studies on TB diagnosis, prognosis, progression, and treatment response. Of 1165 identified studies, 35 met inclusion criteria. Aptamers were utilized for MTB and mycobacterial antigen detection, showcasing notable sensitivity and specificity. Targeted antigens included ESAT-6, HspX, MPT 64, and IFN-γ. Various aptamer-based assays, such as electrochemical, fluorescent, and immunosensors, demonstrated effectiveness. Multiplex assays, particularly for IFN-γ, showed enhanced diagnostic accuracy. Aptamer-based assays exhibited discrimination between active TB and other conditions, showcasing their diagnostic value. Aptamers, especially in conjunction with nanomaterials, show promise in developing advanced TB biosensors with superior detection capabilities. Cost-effective devices with heightened sensitivity for clinical and screening use are crucial for TB control, emphasizing the need for ongoing research in this field.

Aptamers: precision tools for diagnosing and treating infectious diseases

Infectious diseases represent a significant global health challenge, with bacteria, fungi, viruses, and parasitic protozoa being significant causative agents. The shared symptoms among diseases and the emergence of new pathogen variations make diagnosis and treatment complex. Conventional diagnostic methods are laborious and intricate, underscoring the need for rapid, accurate techniques. Aptamer-based technologies offer a promising solution, as they are cost-effective, sensitive, specific, and convenient for molecular disease diagnosis. Aptamers, which are single-stranded RNA or DNA sequences, serve as nucleotide equivalents of monoclonal antibodies, displaying high specificity and affinity for target molecules. They are structurally robust, allowing for long-term storage without substantial activity loss. Aptamers find applications in diverse fields such as drug screening, material science, and environmental monitoring. In biomedicine, they are extensively studied for biomarker detection, diagnostics, imaging, and targeted therapy. This comprehensive review focuses on the utility of aptamers in managing infectious diseases, particularly in the realms of diagnostics and therapeutics.

Advancements in Chronic Myeloid Leukemia detection: Development and evaluation of a novel QCM aptasensor for use in clinical practice

Oncological diseases represent a significant global health challenge, with high mortality rates. Early detection is crucial for effective treatment, and aptamers, which demonstrate superior specificity and stability compared to antibodies, offer a promising avenue for diagnostic advancement. This study presents the design, development and evaluation of a quartz crystal microbalance (QCM) sensor functionalized with the T2-KK1B10 aptamer for the sensitive and specific detection of Chronic Myeloid Leukemia (CML) K562 cells. The research focuses on optimizing the biorecognition layer by adjusting the aptamer conditions, demonstrating the sensor's ability to detect these CML cells with high specificity and sensitivity. The aptamer-modified QCM sensor operates on the principle of mass change detection upon binding of target cells. By employing the Langmuir isotherm model, the performance of the sensor was optimized for the capture of CML cells from biological samples with LOD of 263 K562 cells. The sensor was also successfully regenerated multiple times without sensitivity loss. Validation of the sensor's performance was conducted under controlled laboratory settings, followed by extensive testing utilizing human lyophilized plasma and clinical samples from patients. The sensor exhibited high sensitivity and specificity in the detection of CML cells within clinical specimens, thereby illustrating its potential for practical clinical deployment. This research presents a novel approach to the early diagnosis of CML, facilitating timely intervention and enhanced patient outcomes. The developed aptasensor demonstrates potential for broader application in cancer diagnostics and personalized medicine.

Fructose@histone synergistically improve the performance of DNA-templated Cu NPs: rapid analysis of LAM in tuberculosis urine samples using a handheld fluorometer and a smartphone RGB camera

This study presented a nanoparticle-enhanced aptamer-recognizing homogeneous detection system combined with a portable instrument (NASPI) to quantify lipoarabinomannan (LAM). This system leveraged the high binding affinity of aptamers, the high sensitivity of nanoparticle cascade amplification, and the stabilization effect of dual stabilizers (fructose and histone), and used probe-Cu2+ to achieve LAM detection at concentrations ranging from 10 ag mL-1 to 100 fg mL-1, with a limit of detection of 3 ag mL-1 using a fluorometer. It can also be detected using an independently developed handheld fluorometer or the red-green-blue (RGB) camera of a smartphone, with a minimum detection concentration of 10 ag mL-1. We validated the clinical utility of the biosensor by testing the LAM in the urine of patients. Forty urine samples were tested, with positive LAM results in the urine of 18/20 tuberculosis (TB) cases and negative results in the urine of 6/10 latent tuberculosis infection cases and 10/10 non-TB cases. The assay results revealed a 100% specificity and a 90% sensitivity, with an area under the curve of 0.9. We believe that the NASPI biosensor can be a promising clinical tool with great potential to convert LAM into clinical indicators for TB patients.

New Insights into Aptamers: An Alternative to Antibodies in the Detection of Molecular Biomarkers

Aptamers are short oligonucleotides with single-stranded regions or peptides that recently started to transform the field of diagnostics. Their unique ability to bind to specific target molecules with high affinity and specificity is at least comparable to many traditional biorecognition elements. Aptamers are synthetically produced, with a compact size that facilitates deeper tissue penetration and improved cellular targeting. Furthermore, they can be easily modified with various labels or functional groups, tailoring them for diverse applications. Even more uniquely, aptamers can be regenerated after use, making aptasensors a cost-effective and sustainable alternative compared to disposable biosensors. This review delves into the inherent properties of aptamers that make them advantageous in established diagnostic methods. Furthermore, we will examine some of the limitations of aptamers, such as the need to engage in bioinformatics procedures in order to understand the relationship between the structure of the aptamer and its binding abilities. The objective is to develop a targeted design for specific targets. We analyse the process of aptamer selection and design by exploring the current landscape of aptamer utilisation across various industries. Here, we illuminate the potential advantages and applications of aptamers in a range of diagnostic techniques, with a specific focus on quartz crystal microbalance (QCM) aptasensors and their integration into the well-established ELISA method. This review serves as a comprehensive resource, summarising the latest knowledge and applications of aptamers, particularly highlighting their potential to revolutionise diagnostic approaches.

CRDet: A circle representation detector for lung granulomas based on multi-scale attention features with center point calibration

Lung granuloma is a very common lung disease, and its specific diagnosis is important for determining the exact cause of the disease as well as the prognosis of the patient. And, an effective lung granuloma detection model based on computer-aided diagnostics (CAD) can help pathologists to localize granulomas, thereby improving the efficiency of the specific diagnosis. However, for lung granuloma detection models based on CAD, the significant size differences between granulomas and how to better utilize the morphological features of granulomas are both critical challenges to be addressed. In this paper, we propose an automatic method CRDet to localize granulomas in histopathological images and deal with these challenges. We first introduce the multi-scale feature extraction network with self-attention to extract features at different scales at the same time. Then, the features will be converted to circle representations of granulomas by circle representation detection heads to achieve the alignment of features and ground truth. In this way, we can also more effectively use the circular morphological features of granulomas. Finally, we propose a center point calibration method at the inference stage to further optimize the circle representation. For model evaluation, we built a lung granuloma circle representation dataset named LGCR, including 288 images from 50 subjects. Our method yielded 0.316 mAP and 0.571 mAR, outperforming the state-of-the-art object detection methods on our proposed LGCR.

Epidemiology of extrapulmonary tuberculosis in central Guangxi from 2016 to 2021

The burden of extrapulmonary tuberculosis (EPTB) has gradually increased in recent years, but not enough epidemiological data is available from central Guangxi. To better understand the epidemiology of EPTB in central Guangxi and identify risk factors associated with them, we retrospectively investigated the epidemiology of tuberculosis (TB), especially EPTB, among patients admitted to the Chest Hospital of Guangxi Zhuang Autonomous Region between 2016 and 2021. We excluded those infected with both pulmonary tuberculosis (PTB) and EPTB, reported the proportion and incidence of PTB or EPTB, and compared the demographic characteristics and risk factors of EPTB and PTB cases using univariate and multivariate logistic regression models. Among 30,893 TB patients, 67.25% (20,774) had PTB and 32.75% (10,119) had EPTB. Among EPTB, pleural, skeletal, lymphatic, pericardial, meningeal, genitourinary, intestinal, and peritoneal TB accounted for 49.44%, 27.20%, 8.55%, 4.39%, 3.36%, 1.48%, 0.87%, and 0.79%, respectively. Patients who were younger (age < 25), from rural areas, Zhuang and other ethnic groups, and diagnosed with anemia and HIV infection were more likely to develop EPTB. However, patients with diabetes and COPD were less likely to have EPTB. From 2016 to 2021, the proportion of PTB cases decreased from 69.73 to 64.07%. The percentage of EPTB cases increased from 30.27 to 35.93%, with the largest increase in skeletal TB from 21.48 to 34.13%. The epidemiology and risk factors of EPTB in central Guangxi are different from those of PTB. The incidence of EPTB is increasing and further studies are needed to determine the reasons for it.