Semi-quantification of HIV-1 protease inhibitor concentrations in clinical samples of HIV-infected patients using a gold nanoparticle-based immunochromatographic assay

An immunochromatographic strip sensor for rapid and sensitive detection of candesartan, olmesartan medoxomil, and irbesartan in herbal beverages

Sartans, as a class of antihypertensive drugs, pose a threat to human health when illegally added to herbal beverages. It is crucial to detect sartans in herbal beverages. We have developed a highly sensitive monoclonal antibody against candesartan (CAN), olmesartan medoxomil (OLM), and irbesartan (IRB), with 50% inhibitory concentrations (IC50) that were obtained via indirect enzyme-linked immunosorbent assay (ic-ELISA) as 0.178 ng mL-1, 0.185 ng mL-1, and 0.262 ng mL-1 against CAN, OLM, and IRB, respectively. Based on this monoclonal antibody, we developed a rapid screening method for CAN, OLM, and IRB in herbal beverage samples using an immunochromatographic assay (ICA) strip. Test for 15 minutes after simple and rapid sample pre-treatment and the results of this method can be obtained through naked eye observation. The detection limits (LODs) of the ICA strip for CAN, OLM, and IRB in herbal beverage samples are lower than 0.15 ng mL-1, and the results of the ICA strip and ic-ELISA are consistent in spiked samples and recovery experiments. Therefore, this method can quickly, efficiently, and reliably achieve high-throughput on-site rapid detection of illegally added CAN, OLM, and IRB in herbal beverages.

Semi-quantification and Potency Verification of the HIV Protease Inhibitor Based on the Matrix-Capsid Protein Immobilized Nickel (II)/NTA-Tol/Graphene Oxide/SPCE Electrochemical Biosensor

Human immunodeficiency virus (HIV) causing acquired immune deficiency syndrome (AIDS) is still a global issue. Long-term drug treatment and nonadherence to medication increase the spread of drug-resistant HIV strains. Therefore, the identification of new lead compounds is being investigated and is highly desirable. Nevertheless, a process generally necessitates a significant budget and human resources. In this study, a simple biosensor platform for semi-quantification and verification of the potency of HIV protease inhibitors (PIs) based on electrochemically detecting the cleavage activity of the HIV-1 subtype C-PR (C-SA HIV-1 PR) was proposed. An electrochemical biosensor was fabricated by immobilizing His6-matrix-capsid (H₆MA-CA) on the electrode surface via the chelation to Ni²⁺-nitrilotriacetic acid (NTA) functionalized GO. The functional groups and the characteristics of modified screen-printed carbon electrodes (SPCE) were characterized by Fourier transform infrared (FTIR) spectroscopy, scanning electron microscopy (SEM), and energy-dispersive X-ray spectroscopy (EDS). C-SA HIV-1 PR activity and the effect of PIs were validated by recording changes in electrical current signals of the ferri/ferrocyanide redox probe. The detection of PIs, i.e., lopinavir (LPV) and indinavir (IDV), toward the HIV protease was confirmed by the decrease in the current signals in a dose-dependent manner. In addition, our developed biosensor demonstrates the ability to distinguish the potency of two PIs to inhibit C-SA HIV-1 PR activities. We anticipated that this low-cost electrochemical biosensor would increase the efficiency of the lead compound screening process and accelerate the discovery and development of new HIV drugs.

A Novel Strategy for Rapid Fluorescence Detection of FluB and SARS-CoV-2

Undoubtedly, SARS-CoV-2 has caused an outbreak of pneumonia that evolved into a worldwide pandemic. The confusion of early symptoms of the SARS-CoV-2 infection with other respiratory virus infections made it very difficult to block its spread, leading to the expansion of the outbreak and an unreasonable demand for medical resource allocation. The traditional immunochromatographic test strip (ICTS) can detect one analyte with one sample. Herein, this study presents a novel strategy for the simultaneous rapid detection of FluB/SARS-CoV-2, including quantum dot fluorescent microspheres (QDFM) ICTS and a supporting device. The ICTS could be applied to realize simultaneous detection of FluB and SARS-CoV-2 with one test in a short time. A device supporting FluB/SARS-CoV-2 QDFM ICTS was designed and had the characteristics of being safe, portable, low-cost, relatively stable, and easy to use, ensuring the device could replace the immunofluorescence analyzer in cases where there is no need for quantification. This device does not need to be operated by professional and technical personnel and has commercial application potential.

Micro and Nanoscale Technologies for Diagnosis of Viral Infections

Viral infection is one of the leading causes of mortality worldwide. The growth of globalization significantly increases the risk of virus spreading, making it a global threat to future public health. In particular, the ongoing coronavirus disease 2019 (COVID-19) pandemic outbreak emphasizes the importance of devices and methods for rapid, sensitive, and cost-effective diagnosis of viral infections in the early stages by which their quick and global spread can be controlled. Micro and nanoscale technologies have attracted tremendous attention in recent years for a variety of medical and biological applications, especially in developing diagnostic platforms for rapid and accurate detection of viral diseases. This review addresses advances of microneedles, microchip-based integrated platforms, and nano- and microparticles for sampling, sample processing, enrichment, amplification, and detection of viral particles and antigens related to the diagnosis of viral diseases. Additionally, methods for the fabrication of microchip-based devices and commercially used devices are described. Finally, challenges and prospects on the development of micro and nanotechnologies for the early diagnosis of viral diseases are highlighted.

Functionalized gold nanoparticles: promising and efficient diagnostic and therapeutic tools for HIV/AIDS

Functionalized gold nanoparticles are recognized as promising vehicles in the diagnosis and treatment of human immunodeficiency virus (HIV) owing to their excellent biocompatibility with biomolecules (like DNA or RNA), their potential for multivalency and their unique optical and structural properties. In this context, this review article focuses on the diverse detection abilities and delivery and uptake methodologies of HIV by targeting genes and proteins using gold nanoparticles on the basis of different shapes and sizes in order to promote its effective expression. In addition, recent trends in gold nanoparticle mediated HIV detection, delivery and uptake and treatment are highlighted considering their cytotoxic effects on healthy human cells.

Gold nanoparticle-decorated metal organic frameworks on immunochromatographic assay for human chorionic gonadotropin detection

Gold nanoparticle-decorated metal organic frameworks (MOF@AuNPs) with significantly enhanced color signal intensity were synthesized through in situ growth of AuNPs on the MOF skeleton. The resultant MOF@AuNP nanocomposites were characterized with 16.7-fold higher absorbance than conventional 40 nm AuNPs (AuNP₄₀). Thus, for the first time, we applied it as a signal amplification label to improve the immunochromatographic assay (ICA) of human chorionic gonadotropin (HCG). The detection limit of our enhanced ICA was 1.69 mIU/mL, which is ca. 10.6-fold improvement in sensitivity compared to traditional AuNP₄₀-ICA. The recoveries of this MOF@AuNPs-ICA ranged from 86.03 to 119.22%, with coefficients of variation of 3.05 to 13.74%. The reliability and practicability were further validated by the clinically used chemiluminescence immunoassay method. Given their excellent signal amplification ability, the proposed MOF@AuNPs could serve as an ideal ICA label for rapid and sensitive detection of disease biomarkers. Graphical abstract.

Comparison of three sample addition methods in competitive and sandwich colloidal gold immunochromatographic assay

Immunochromatographic assays (ICAs) are mainstream point-of-care diagnostic tools in disease control, food safety, and environmental monitoring. However, the important issue pertaining to the influence of sample addition methods on the detection performance of ICAs has not been addressed, and related information is still lacking. Herein, we selected the well-accepted gold nanoparticles (AuNPs) as visual labels. AuNP-based ICA was then used to explore the effects of three sample addition methods (i.e., dry, wet, and insert) on the analytical performance of ICAs by using competitive and sandwich models. Under optimized conditions, the competitive ICA with clenbuterol as an analyte showed a negligible difference (p > 0.05) in the detection performance of the three methods in ideal phosphate buffered saline solution. However, the wet method demonstrated the worst performance in pork samples (p < 0.05). The sandwich ICA strip with human chorionic gonadotropin as an analyte revealed the significantly different analytical performances of the three approaches in phosphate buffer (PB) solution and spiked serum (p < 0.05). Two independent linear correlations were observed with the increase in target concentration. However, for the wet method in the PB solution and serum, the first linear correlation was at a relatively narrow target concentration range, and the second linear correlation was at a wider concentration range compared with those for the dry and insert methods. Our findings demonstrated that sample addition methods slightly influence competitive ICAs (p > 0.05) but remarkably affect sandwich ICAs (p < 0.05). We believe that this study can further explain the differences in detection results for the same target analyte in actual ICA detection. The results may serve as a reference in the rational selection of the appropriate sample addition method for succeeding ICA works.

HIV biosensors for early diagnosis of infection: The intertwine of nanotechnology with sensing strategies

Human immunodeficiency virus (HIV) is a lentivirus that leads to acquired immunodeficiency syndrome (AIDS). With increasing awareness of AIDS emerging as a global public health threat, different HIV testing kits have been developed to detect antibodies (Ab) directed toward different parts of HIV. A great limitation of these tests is that they can not detect HIV antibodies during early virus infection. Therefore, to overcome this challenge, a wide range of biosensors have been developed for early diagnosis of HIV infection. A significant amount of these studies have been focused on the application of nanomaterials for improving the sensitivity and accuracy of the sensing methods. Following an introduction into this field, a first section of this review covers the synthesis and applicability of such nanomaterials as metal nanoparticles (NPs), quantum dots (QDs), carbon-based nanomaterials and metal nanoclusters (NCs). A second larger section covers the latest developments concerning nanomaterial-based biosensors for HIV diagnosis, with paying a special attention to the determination of CD4⁺ cells as a hall mark of HIV infection, HIV gene, HIV p24 core protein, HIV p17 peptide, HIV-1 virus-like particles (VLPs) and HIV related enzymes, particularly those that are passed on from the virus to the CD⁴⁺ T lymphocytes and are necessary for viral reproduction within the host cell. These studies are described in detail along with their diverse principles/mechanisms (e.g. electrochemistry, fluorescence, electromagnetic-piezoelectric, surface plasmon resonance (SPR), surface enhanced Raman spectroscopy (SERS) and colorimetry). Despite the significant progress in HIV biosensing in the last years, there is a great need for the development of point-of-care (POC) technologies which are affordable, robust, easy to use, portable, and possessing sufficient quantitative accuracy to enable clinical decision making. In the final section, the focus is on the portable sensing devices as a new standard of POC and personalized diagnostics.