We report a switchable, templated polymerization system where the strength of the templating effect can be modulated by solution pH and/or ionic strength. The responsiveness to these cues is incorporated through a dendritic polyamidoamine-based template of which the charge density depends on pH. The dendrimers act as a template for the polymerization of an oppositely charged monomer, namely sodium styrene sulfonate. We show that the rate of polymerization and maximum achievable monomer conversion are directly related to the charge density of the template, and hence the environmental pH. The polymerization could effectively be switched "ON" and "OFF" on demand, by cycling between acidic and alkaline reaction environments. These findings break ground for a novel concept, namely harnessing co-assembly of a template and growing polymer chains with tunable association strength to create and control coupled polymerization and self-assembly pathways of (charged) macromolecular building blocks.
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http://dx.doi.org/10.1002/anie.202206780 | DOI Listing |
Biol Lett
January 2025
Discovery, InsideOutBio , Charlestown, MA, USA.
This paper is focused on the origins of the contemporary genetic code. A novel explanation is proposed for how the mapping of nucleotides in DNA to amino acids in proteins arose that derives from repeat nucleotide sequences able to form alternative nucleic acid structures (ANS), such as the unusual left-handed Z-DNA, triplex, G-quadruplex and I-motif conformations. The scheme identifies sequence-specific contacts that map ANS repeats to dipeptide polymers (DPS).
View Article and Find Full Text PDFJ Chromatogr A
January 2025
Key Laboratory of Protection, Development and Utilization of Medicinal Resources in Liupanshan Area, Ministry of Education, College of Pharmacy, Ningxia Medical University, Yinchuan 750004, China; Key Laboratory of Ningxia Minority Medicine Modernization, Ministry of Education, Ningxia Medical University, Yinchuan 750004, China. Electronic address:
Molecularly imprinted polymers (MIPs) are typically synthesized in organic solvents, leading to poor compatibility with water, weak affinity and selectivity for target molecules in aqueous media. To address these challenges, a green and sustainable synthesis of sandwich bread-like ATP@MIP was conducted using polyethylenimide (PEI) and deep eutectic solvent (DES) as hydrophilic bi-functional monomers via layer-by-layer self-assembly on the attapulgite (ATP) carrier. The new ATP@MIP can provide a higher density of imprinting sites with more orderly and uniform distribution due to inhibiting the competitive polymerization between PEI and DES, thereby significantly enhancing recognition ability.
View Article and Find Full Text PDFACS Nano
January 2025
Conte Center for Polymer Research, Polymer Science and Engineering, University of Massachusetts Amherst, Amherst, Massachusetts 01003, United States.
Bottlebrush block copolymers (BBCPs) are a unique class of materials that contain a backbone with densely grafted and chemically distinct polymeric side chains. The nonlinear architecture of BBCPs provides numerous degrees of freedom in their preparation, including control over key parameters such as grafting density, side chain length, block arrangement, and overall molecular weight. This uniquely branched structure provides BBCPs with several important distinctions from their linear counterparts, including sterically induced side chain and backbone conformations, rapid and large self-assembled nanostructures, and reduced or eliminated entanglement effects (assuming sufficient grafting density and that the molecular weight of the side chains is below their respective entanglement molecular weight).
View Article and Find Full Text PDFBiophys Rev
December 2024
Amity Institute of Molecular Medicine and Stem Cell Research, Amity University Uttar Pradesh, 201313 Noida, India.
Amyloid fibrils, historically stigmatized due to their association with diseases like Alzheimer's and Parkinson's, are now recognized as a distinct class of functional proteins with extraordinary potential. These highly ordered, cross-β-sheet protein aggregates are found across all domains of life, playing crucial physiological roles. In bacteria, functional amyloids like curli fibers are essential for surface adhesion, biofilm formation, and viral DNA packaging.
View Article and Find Full Text PDFSmall
January 2025
College of Chemical Engineering, Fuzhou University, Fuzhou, Fujian, 350116, China.
The development of diverse microstructures has substantially contributed to recent progress in high-performance electromagnetic wave (EMW) absorption materials, providing a versatile platform for the modulation of absorption properties. Exploring multidimensional microstructures and developing tailored and gentle strategies for their precise optimization can substantially address the current challenges posed by relatively unclear underlying mechanisms. Here, a series of 2D/1D heterogeneous NiO@PPy composites featuring hollow hierarchical microstructures are successfully synthesized using a straightforward strategy combining sacrificial templating with chemical oxidative polymerization.
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