A paper-based visual fluorescence immunoassay is presented for the detection of matrix metalloproteinase-7 (MMP7) that is related to renal cancer. The method is based on the distance-dependent fluorescence quenching of CdTe quantum dots (QDs) on a nitrocellulose membrane by Ag following a sandwich-type immunoreaction on microtiter wells using silver nanoparticle (AgNP)-labeled secondary antibody- and primary antibody-coated microtiter wells. The silver nanoparticles captured in the well are dissolved with HNO, while the quenching effect of QDs is based on silver ion-exchange reaction under 365-nm excitation light irradiation. Increasing concentration of released Ag, thus higher concentration of the protein, leads to an increased distance of quenching on the nitrocellulose membrane. The paper-based immunoassay by combination of AgNP-assisted ion-exchange reaction with QD gives good distance-dependent responses and allows the detection of MMP7 at a concentration as low as 7.3 pg mL. The coefficients of variation are less than 6.9% and 12.4% for intra-assay and inter-assay, respectively. High specificity and long-term stability are achieved during the assay. Importantly, the testing of human serum samples using our strategy shows well-matched results with commercial human MMP7 ELISA kits. Graphical abstract A distance-dependent visual immunoassay is developed for the determination of serum matrix metalloproteinase-7 on CdTe quantum dot-impregnated paper with silver ion-exchange reaction.
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http://dx.doi.org/10.1007/s00604-020-04546-7 | DOI Listing |
R Soc Open Sci
January 2025
Fundamental and Applied Sciences Department, Centre of Ionic Liquids, Universiti Teknologi PETRONAS, Seri Iskandar, Perak Darul Ridzuan 32610, Malaysia.
Six 1,8-diazabicyclo(5.4.0)undec-7-ene-based ionic liquids (ILs) linked with ethyl or propyl hydroxyl cations, coupled with thiocyanate, dicyanamide and bistriflimide anions, were synthesized through a two-step reaction: quaternization and ion exchange.
View Article and Find Full Text PDFTurk J Chem
December 2024
Laboratory of Physical Chemistry of Materials (LPCM), Faculty of Sciences, University of Amar Telidji, Laghouat, Algeria.
In processes such as electrodialysis, the applied electrical potential is constrained by concentration polarization at the membrane/solution interface. This polarization, which intensifies at higher current densities, impedes ion transport efficiency and may lead to problems such as salt precipitation, membrane degradation, and increased energy consumption. Therefore, understanding concentration polarization is essential for enhancing membrane performance, improving efficiency, and reducing operational costs.
View Article and Find Full Text PDFFood Res Int
January 2025
Department of Food Science, University of Copenhagen, Rolighedsvej 26, 1958 Frederiksberg, Denmark. Electronic address:
The efficiency of ultrafiltration (UF) of acidified skim milk (SM) is impaired by protein aggregation and mineral scaling. The aim of this study is to assess the potential of acidification by electrodialysis with bipolar membranes (EDBM), in comparison with citric acid (CA), prior to the UF process on filtration performance, fouling and composition of the protein concentrates. Electro-acidification, facilitated by a water-splitting reaction, decreased the pH of milk to ∼ 5.
View Article and Find Full Text PDFFood Res Int
January 2025
Institute for Global Health Innovations, Duy Tan University, Da Nang 550000, Viet Nam; Faculty of Medicine, Duy Tan University, Da Nang 550000, Viet Nam. Electronic address:
The discovery of food-derived biopeptides is becoming increasingly prevalent in the scientific community. Some peptides possess multiple biological functions that can confer health benefits through various mechanisms following ingestion. The present review targets food-derived antioxidant and mineral-binding peptides (AMBPs) including their production procedure i.
View Article and Find Full Text PDFPhys Chem Chem Phys
January 2025
Indian Institute of Technology Guwahati, Assam 781039, India.
The oscillatory Belousov-Zhabotinsky (BZ) reaction is often used for the study of rotating spiral waves that are responsible for life-threatening cardiac arrhythmia. In this work, we explore the influence of a concentration gradient on the dynamics of spiral waves in the BZ-reaction system. Using ion-exchange resin beads, we introduce a gradient of hydrogen ions in a thin layer of BZ gel hosting a spiral wave.
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