The global pandemic of COVID-19 continues to be an important threat, especially with the fast transmission rate observed after the discovery of novel mutations. In this perspective, prompt diagnosis requires massive economical and human resources to mitigate the disease. The current study proposes a rational design of a colorimetric lateral flow immunoassay (LFA) based on the repurposing of human samples to produce COVID-19-specific antigens and antibodies in combination with a novel dye-loaded polymersome for naked-eye detection. A group of 121 human samples (61 serums and 60 nasal swabs) were obtained and analyzed by RT-PCR and ELISA. Pooled samples were used to purify antibodies using affinity chromatography, while antigens were purified via magnetic nanoparticles-based affinity. The purified proteins were confirmed for their specificity to COVID-19 via commercial LFA, ELISA, and electrochemical tests in addition to sodium dodecyl sulfate-polyacrylamide gel electrophoresis analysis. Polymersomes were prepared using methoxy polyethylene glycol- b -polycaprolactone (mPEG- b -PCL) diblock copolymers and loaded with a Coomassie Blue dye. The polymersomes were then functionalized with the purified antibodies and applied for the preparation of two types of LFA (antigen test and antibody test). Overall, the proposed diagnostic tests demonstrated 93 and 92.2% sensitivity for antigen and antibody tests, respectively. The repeatability (92–94%) and reproducibility (96–98%) of the tests highlight the potential of the proposed LFA. The LFA test was also analyzed for stability, and after 4 weeks, 91–97% correct diagnosis was observed. The current LFA platform is a valuable assay that has great economical and analytical potential for widespread applications.

Plant‐derived bioactive peptides demonstrate great potential given their availability and cost‐effectiveness. In this study, barley (Hordeum vulgare L.) grain proteins were explored for bioactive peptides with potential health applications. Gross grain proteins were obtained through aqueous extraction, after which, trypsin hydrolysis was performed. The hydrolysis process provided high peptide yields reaching 11%. The peptide hydrolysates were evaluated for their antioxidant and metal chelating activities, DPP4 inhibition, deglycation, and antimicrobial activity. The obtained results demonstrated biological activity levels of great importance and comparable to reference molecules. To confirm the experimental results, barley grain protein sequences were simulated for hydrolysis and explored for potential bioactive peptides using the FeptideDB. Indeed, barley grain proteins contain a great diversity of bioactive peptides with various biological activities. The current data highlights the promising therapeutic application of barley‐derived bioactive peptides. Further molecular and sequencing approaches are necessary to identify and characterize these peptides. Practical applications Barley (Hordeum vulgare L.) grain proteins are widely used cereals for nutrition and beverages. Their availability and low‐cost make them good sources for functional food exploration. We have described the potential of bioactive peptides obtained from barley grain proteins that have various activities including DPP4 inhibitory, antioxidant, antimicrobial, metal chelating, and deglycation activities. This data supports the potential of these peptides in biomedicine applications as a treatment option or as food supplement. Hence, the described peptide sequences could be exploited and industrialized by artificial synthesis and be proposed as food supplements or included in protein mixes for athletes.

No abstract

The construction of a rapid and easy immunofluorescence bioassay for SARS-CoV-2 detection is described. We report for the first time a novel one-pot synthetic approach for simultaneous photoinduced step-growth polymerization of pyrene (Py) and ring-opening polymerization of ε-caprolactone (PCL) to produce a graft fluorescent copolymer PPy- g -PCL that was conjugated to SARS-CoV-2-specific antibodies using EDC/NHS chemistry. The synthesis steps and conjugation products were fully characterized using standard spectral analysis. Next, the PPy- g -PCL was used for the construction of a dot-blot assay which was calibrated for applications to human nasopharyngeal samples. The analytical features of the proposed sensor showed a detection range of 6.03–8.7 LOG viral copy mL −1 (Ct Scores: 8–25), the limit of detection (LOD), and quantification (LOQ) of 1.84 and 6.16 LOG viral copy mL −1 , respectively. The repeatability and reproducibility of the platform had a coefficient of variation (CV) ranging between 1.2 and 5.9%. The fluorescence-based dot-blot assay was tested with human samples. Significant differences were observed between the fluorescence intensity of the negative and positive samples, with an overall correct response of 93.33%. The assay demonstrated a high correlation with RT-PCR data. This strategy opens new insights into simplified synthesis procedures of the reporter molecules and their high potential sensing and diagnosis applications. Graphical abstract Supplementary Information The online version contains supplementary material available at 10.1007/s00604-022-05244-2.

No abstract

Supply shortage for the development and production of preventive, therapeutic, and diagnosis tools during the COVID-19 pandemic is an important issue affecting the wealthy and poor nations alike. Antibodies and antigens are especially needed for the production of immunological-based testing tools such as point-of-care tests. Here, we propose a simple and quick magnetic nanoparticle (MNP)based separation/isolation approach for the repurposing of infected human samples to produce specific antibodies and antigen cocktails. Initially, an antibody cocktail was purified from serums via precipitation and immunoaffinity chromatography. Purified antibodies were conjugated onto MNPs and used as an affinity matrix to separate antigens. The characterization process was performed by ELISA, SDS-PAGE, electrochemistry, isothermal titration calorimetry, and LC-Q-TOF-MS/MS analyses. The MNP-separated peptides can be used for mass spectrometry-based as well as paper-based lateral flow assay diagnostic. The exploitation of the current workflow for the development of efficient diagnostic tools, specific treatments, and fundamental research can significantly impact the present or eventual pandemic. This workflow can be considered as a two birds, one stone-like strategy.

No abstract

No abstract