Improving lateral-flow immunoassay (LFIA) diagnostics via biomarker enrichment for mHealth

AlphaFold2 in biomedical research: facilitating the development of diagnostic strategies for disease

Proteins, as the primary executors of physiological activity, serve as a key factor in disease diagnosis and treatment. Research into their structures, functions, and interactions is essential to better understand disease mechanisms and potential therapies. DeepMind's AlphaFold2, a deep-learning protein structure prediction model, has proven to be remarkably accurate, and it is widely employed in various aspects of diagnostic research, such as the study of disease biomarkers, microorganism pathogenicity, antigen-antibody structures, and missense mutations. Thus, AlphaFold2 serves as an exceptional tool to bridge fundamental protein research with breakthroughs in disease diagnosis, developments in diagnostic strategies, and the design of novel therapeutic approaches and enhancements in precision medicine. This review outlines the architecture, highlights, and limitations of AlphaFold2, placing particular emphasis on its applications within diagnostic research grounded in disciplines such as immunology, biochemistry, molecular biology, and microbiology.

Monoclonal Antibodies Application in Lateral Flow Immunochromatographic Assays for Drugs of Abuse Detection

Lateral flow assays (lateral flow immunoassays and nucleic acid lateral flow assays) have experienced a great boom in a wide variety of early diagnostic and screening applications. As opposed to conventional examinations (High Performance Liquid Chromatography, Polymerase Chain Reaction, Gas chromatography-Mass Spectrometry, etc.), they obtain the results of a sample's analysis within a short period. In resource-limited areas, these tests must be simple, reliable, and inexpensive. In this review, we outline the production process of antibodies against drugs of abuse (such as heroin, amphetamine, benzodiazepines, cannabis, etc.), used in lateral flow immunoassays as revelation or detection molecules, with a focus on the components, the principles, the formats, and the mechanisms of reaction of these assays. Further, we report the monoclonal antibody advantages over the polyclonal ones used against drugs of abuse. The perspective on aptamer use for lateral flow assay development was also discussed as a possible alternative to antibodies in view of improving the limit of detection, sensitivity, and specificity of lateral flow assays.

Design and site-directed immobilization of single-chain Fv antibody to polystyrene latex beads via material-binding peptides and application to latex turbidimetric assay

In this study, immobilization of single-chain Fv (scFv) antibodies on the surfaces of polystyrene (PS) latex beads via material-binding peptides was investigated for sensitive immuno-turbidimetric assay of C-reactive protein (CRP). Anti-CRP scFvs fused with polystyrene-binding peptide (PS-tag) and poly(methylmethacrylate)-binding peptide (PMMA-tag) were over-expressed in Escherichia coli cells and recovered in the active form following refolding. The beads with PMMA-tag-fused scFv (scFv-PM) were successfully suspended with sufficient dispersion at pH 8.0. Three types of alternative scFv-PMs with a penta-asparatic acid tag (D5-tag) introduced at different positions were then designed. All of the D5-tagged scFv-PMs were successfully immobilized on the surfaces of beads with no significant change in the diameter of the latex beads at pH levels ranging from 6.0 to 8.0. According to the results of turbidimetric assay for the detection of CRP, 13 ng/ml of CRP was detectable using beads with D5-tagged scFv-PMs at 400 ng/cm³, and no turbidity change was observed in the absence of antigen. When the density of scFv-PM was 250 ng/cm², which was 63% of the maximum density, the beads were dispersed well and reactive with the antigen at a concentration range comparable to those with D5-tagged scFv-PMs. These results indicate that controlling charge density on the surface of beads after site-directed immobilization is definitely important in order to maintain high levels of dispersion and reactivity. Thus, the usefulness of the scFv-PM as well as D5-tagged scFv-PMs developed in the present study should be significant when used as ligand antibodies in the preparation of immuno-latex beads.

Applications of sequencing technology in clinical microbial infection

Infectious diseases are a type of disease caused by pathogenic microorganisms. Although the discovery of antibiotics changed the treatment of infectious diseases and reduced the mortality of bacterial infections, resistant bacterial strains have emerged. Anti‐infective therapy based on aetiological evidence is the gold standard for clinical treatment, but the time lag and low positive culture rate of traditional methods of pathogen diagnosis leads to relative difficulty in obtaining the evidence of pathogens. Compared with traditional methods of pathogenic diagnosis, next‐generation and third‐generation sequencing technologies have many advantages in the detection of pathogenic microorganisms. In this review, we mainly introduce recent progress in research on pathogenic diagnostic technology and the applications of sequencing technology in the diagnosis of pathogenic microorganisms. This review provides new insights into the application of sequencing technology in the clinical diagnosis of microorganisms.

Direct transfer of HRPII-magnetic bead complexes to malaria rapid diagnostic tests significantly improves test sensitivity

Background

The characteristic ease of use, rapid time to result, and low cost of malaria rapid diagnostic tests (RDTs) promote their widespread use at the point-of-care for malaria detection and surveillance. However, in many settings, the success of malaria elimination campaigns depends on point-of-care diagnostics with greater sensitivity than currently available RDTs. To address this need, a sample preparation method was developed to deliver more biomarkers onto a malaria RDT by concentrating the biomarker from blood sample volumes that are too large to be directly applied to a lateral flow strip.

Methods

In this design, Ni–NTA-functionalized magnetic beads captured the Plasmodium falciparum biomarker HRPII from a P. falciparum D6 culture spiked blood sample. This transfer of magnetic beads to the RDT was facilitated by an inexpensive 3D-printed apparatus that aligned the sample tube with the sample deposition pad and a magnet beneath the RDT. Biomarkers were released from the bead surface onto the lateral flow strip using imidazole-spiked running buffer. Kinetics of HRPII binding to the Ni–NTA beads as a function of blood sample volume were explored prior to determining the effect of the proposed method on the limit of detection of Paracheck RDTs.

Results

More than 80 % of HRPII biomarkers were extracted from blood sample volumes ranging from 25 to 250 µL. The time required to reach 80 % binding ranged from 5 to 60 min, depending on sample volume. Using 250 μL of blood and a 30-min biomarker binding time, the limit of detection of the Paracheck Pf RDT brand was improved by 21-fold, resulting in a limit of detection below 1 parasite/μL.

Conclusions

This approach has the sensitivity and simplicity required to assist in malaria elimination campaigns in settings with limited access to clinical and laboratory resources.

Electronic supplementary material

The online version of this article (doi:10.1186/s12936-016-1448-6) contains supplementary material, which is available to authorized users.