Unlabelled: In this study, an enzyme-free biosensor was developed for sensitive and specific detection of Salmonella typhimurium (S. typhimurium) using curcumin (CUR) as signal reporter and 1,2,4,5-tetrazine (Tz)-trans-cyclooctene (TCO) click chemistry for signal amplification.
Methods: Nanoparticles composed of CUR and bovine serum albumin (BSA) were formulated and reacted with Tz and TCO to form Tz-TCO-CUR conjugates through Tz-TCO click chemistry. Then, the Tz-TCO-CUR conjugates were functionalized with polyclonal antibodies (pAbs) against S. typhimurium to form CUR-TCO-Tz-pAb conjugates. Magnetic nanoparticles (MNPs) conjugated with monoclonal antibodies (mAbs) against S. typhimurium through streptavidin-biotin binding were used to specifically and efficiently separate S. typhimurium from the background by magnetic separation. CUR-TCO-Tz-pAb conjugates were reacted with the magnetic bacteria to form CUR-Tz-TCO bacteria. Finally, CUR was released quickly from the CUR-Tz-TCO bacteria in the presence of NaOH, and the color change was measured at the characteristic wavelength of 468 nm for bacteria quantification.
Results: A linear relationship between absorbance at 468 nm and concentration of S. typhimurium from 102 to 106 CFU/mL was found. The lower detection limit was calculated to be as low as 50 CFU/mL and the mean recovery was 107.47% for S. typhimurium in spiked chicken samples.
Conclusion: This biosensor has the potential for practical applications in the detection of foodborne pathogens.
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http://dx.doi.org/10.7150/thno.29025 | DOI Listing |
J Hazard Mater
January 2025
State Key Laboratory of Marine Food Processing and Safety Control, Dalian Polytechnic University, Dalian, Liaoning 116034, PR China. Electronic address:
The existence of ochratoxin A (OTA) in agricultural products poses significant threats to human health and environment, underscoring the critical need for its prompt and precise quantification. A particle counting immunosensor for the highly sensitive detection of OTA was presented, employing SiO@CuO nanoparticles to facilitate click chemistry. The quantity of SiO@CuO nanoparticles, and consequently the Cu²⁺ concentration, can be directly altered through the immune response involving OTA.
View Article and Find Full Text PDFSci Rep
January 2025
Department of Chemistry, Yazd University, Yazd, Iran.
A new humic acid-based nanomagnetic copper(II) composite was prepared and used as an eco-friendly recoverable catalyst for synthesizing 1,4-disubstituted 1,2,3-triazoles. The synthesis was done via the three-component click reaction of alkyl halide, sodium azide, and terminal alkyne with good to excellent yield. A simple magnetic copper acetate composite, FeO@HA-Cu(OAc), was prepared using humic acid and characterized by SEM, TEM, XRD, EDX, EDS-mapping, VSM, TGA, AAS, and FT-IR.
View Article and Find Full Text PDFJ Phys Chem B
January 2025
Department of Chemistry, University of Pennsylvania, Philadelphia, Pennsylvania 19104, United States.
Computationally designed 29-residue peptides yield tetra-α-helical bundles with symmetry. The "bundlemers" can be bifunctionally linked via thiol-maleimide cross-links at their N-termini, yielding supramolecular polymers with unusually large, micrometer-scale persistence lengths. To provide a molecularly resolved understanding of these systems, all-atom molecular modeling and simulations of linked bundlemers in explicit solvent are presented.
View Article and Find Full Text PDFACS Appl Mater Interfaces
January 2025
Interdisciplinary Nanoscience Center, Aarhus University, Gustav Wieds Vej 14, 8000 Aarhus C, Denmark.
High-throughput measurement of cellular traction forces at the nanoscale remains a significant challenge in mechanobiology, limiting our understanding of how cells interact with their microenvironment. Here, we present a novel technique for fabricating protein nanopatterns in standard multiwell microplate formats (96/384-wells), enabling the high-throughput quantification of cellular forces using DNA tension gauge tethers (TGTs) amplified by CRISPR-Cas12a. Our method employs sparse colloidal lithography to create nanopatterned surfaces with feature sizes ranging from sub 100 to 800 nm on transparent, planar, and fully PEGylated substrates.
View Article and Find Full Text PDFChem Sci
January 2025
Department of Chemistry, Imperial College London Molecular Sciences Research Hub, 82 Wood Lane, White City Campus London W12 0BZ UK
The blood-brain-barrier prevents many imaging agents and therapeutics from being delivered to the brain that could fight central nervous system diseases such as Alzheimer's disease and strokes. However, techniques such as the use of stapled peptides or peptide shuttles may allow payloads through, with bioconjugation achieved bio-orthogonal tetrazine/norbornene click chemistry. A series of lanthanide-tetrazine probes have been synthesised herein which could be utilised in bio-orthogonal click chemistry with peptide-based delivery systems to deliver MRI agents through the blood-brain-barrier.
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