Most metal probes based on gold nanoparticles (AuNPs) are designed for free metal ions in synthetic waters, and very few are applicable in the detection of metal-organic complexes ubiquitous in real water samples. In this study, we proposed a novel colorimetric nanoprobe strategy for complexed Cr(III) species based on the analyte-induced aggregation of AuNPs, as coated by a cationic surfactant tributylhexadecylphosphonium bromide (THPB) instead of traditional carboxyl modifiers. Such a detection system could be realized both naked eye and/or UV-vis spectroscopy with detection limits of 8.0 and 0.29 μM, respectively, much lower than its allowable maximum level in industrial effluent as regulated by China EPA (1.5 mg Cr/L, ∼30 μM). The proposed detection system also exhibits high selectivity against various interfering substances including free ions, small organic molecules, and other metal-citrate complexes. The unique hydrolysis and extremely slow decomplexation of Cr(III) are believed to favor the formation of the specific interaction between Cr(III)-citrate and THPB-AuNPs, as verified by X-ray photoelectron spectroscopy characterization, thus endowing the nanoprobe with specific discrimination of the complexed Cr(III) the aggregation of THPB-AuNPs. Also, the THPB-AuNPs could be stored at room temperature for 30 days and maintain constant detection performance. Moreover, the quantitative detection of Cr(III)-organic complexes with the background of various real water samples agreed well with that based on inductively coupled plasma atomic emission spectrometry, making it an attractive alternative for on-site detection of authentic samples containing Cr(III)-organic species.
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http://dx.doi.org/10.1021/acs.analchem.0c04688 | DOI Listing |
Chembiochem
December 2024
China Three Gorges University, College of Biological and Pharmaceutical Sciences, No. 8, Daxue Road, 443002, Yichang, CHINA.
Methylation modification is a critical regulatory mechanism in epigenetics, playing a significant role in various biological processes. N6-methyladenosine (m6A) is the most prevalent modification found in RNA. This modification is dynamic and reversible, regulated by methyltransferases and demethylases.
View Article and Find Full Text PDFACS Sens
December 2024
School of Mechanical Engineering, Southeast University, Nanjing 211189, People's Republic of China.
Background noise interferes with the accurate detection of early tumor biomarkers. This study introduces a method that effectively reduces background noise to enhance detection accuracy by combining a color-coded signaling approach with the unique fluorescent properties and room-temperature tunable quantum spin characteristics of fluorescent diamonds (FNDs) with nitrogen-vacancy centers. In this approach, a red signal indicates the presence of the target analyte within the spectral region, a green signal indicates its absence, and a yellow signal indicates the need for further analysis using FNDs' quantum spin properties for optical detection magnetic resonance (ODMR) to distinguish the FND signal from background noise.
View Article and Find Full Text PDFNano Lett
December 2024
School of Pharmacy, Shenzhen University Medical School, Shenzhen University, Shenzhen, 518055, China.
Drug nanocrystal engineering is an attractive pharmaceutical approach to enhancing the oral bioavailability of poorly soluble drugs. The mechanism of drug nanocrystal stabilization, however, is unclear. Here we developed andrographolide nanocrystals (AG-NCs) with various nonionic surfactants (Pluronic-F127, TPGS, or Brij-S20).
View Article and Find Full Text PDFElife
December 2024
Howard Hughes Medical Institute, Stanford University, Stanford, United States.
Defining the cellular factors that drive growth rate and proteome composition is essential for understanding and manipulating cellular systems. In bacteria, ribosome concentration is known to be a constraining factor of cell growth rate, while gene concentration is usually assumed not to be limiting. Here, using single-molecule tracking, quantitative single-cell microscopy, and modeling, we show that genome dilution in cells arrested for DNA replication limits total RNA polymerase activity within physiological cell sizes across tested nutrient conditions.
View Article and Find Full Text PDFThis review delves into the evolving landscape of mediated drug delivery, focusing on the versatility of a variety of drug delivery vehicles such as microspheres, microbots, and nanoparticles (NPs). The review also expounds on the critical components and mechanisms for light-mediated drug delivery, including photosensitizers and light sources such as visible light detectable by the human eye, ultraviolet (UV) light, shorter wavelengths than visible light, and near-infrared (NIR) light, which has longer wavelength than visible light. This longer wavelength has been implemented in drug delivery for its ability to penetrate deeper tissues and highlighted for its role in precise and controlled drug release.
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