The present report describes the synthesis of a hydroxyl terminal PAMAM dendrimer (PAMAM-OH) derivative (PAMSPF). The hydroxyls of PAMAM-OH were attached to S-Methyl-l-cysteine (SMLC) via an acid-labile ester bond, named as β-thiopropionate bond, followed by modification with folic acid (FA) through a polyethylene glycol (PEG) linker. The degrees of attachment of SMLC and FA to the PAMAM-OH backbone were 83.9% and 12.8%, respectively. PAMSPF could condense DNA to form spherical nanoparticles with particle sizes of ∼200nm and remain stable in the presence of heparin and nuclease. The β-thiopropionate bond in PAMSPF was hydrolyzed completely and the DNA release rate was 95.8±3.3% after incubation under mildly acidic conditions at 37°C for 3h. PAMSPF/DNA was less cytotoxic to KB and HepG2 cells and exhibited a higher gene transfection efficiency than native PAMAM/DNA. The uptake assays showed that PAMSPF/DNA entered KB cells within 0.5h through folate receptor-mediated endocytosis and escaped from endosomes within 2h. In addition, PAMSPF/DNA displayed long circulation time along with excellent targeting of tumor sites in vivo. These findings demonstrate that PAMSPF is an excellent carrier for safe and effective gene delivery.
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http://dx.doi.org/10.1016/j.ijpharm.2016.05.060 | DOI Listing |
Sci Rep
January 2025
Department of Physics and Astronomy, Aarhus University, Aarhus, Denmark.
Roaming reactions involving a neutral fragment of a molecule that transiently wanders around another fragment before forming a new bond are intriguing and peculiar pathways for molecular rearrangement. Such reactions can occur for example upon double ionization of small organic molecules, and have recently sparked much scientific interest. We have studied the dynamics of the [Formula: see text]-roaming reaction leading to the formation of [Formula: see text] after two-photon double ionization of ethanol and 2-aminoethanol, using an XUV-UV pump-probe scheme.
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January 2025
School of Pharmacy, Nanjing University of Chinese Medicine, Nanjing, China.
Stereocontrolled construction of tetrasubstituted olefins has been an attractive issue yet remains challenging for synthetic chemists. In this manuscript, alkynyl selenides, when treated with ArBCl, are subject to an exclusive 1,1-carboboration, affording tetrasubstituted alkenes with excellent levels of E-selectivity. Detailed mechanistic studies, supported by DFT calculations, elucidates the role of selenium in this 1,1-addition process.
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January 2025
School of Physical and Mathematical Sciences, Nanyang Technological University, Singapore, 637371, Singapore.
Designing efficient Ruthenium-based catalysts as practical anodes is of critical importance in proton exchange membrane water electrolysis. Here, we develop a self-assembly technique to synthesize 1 nm-thick rutile-structured high-entropy oxides (RuIrFeCoCrO) from naked metal ions assembly and oxidation at air-molten salt interface. The RuIrFeCoCrO requires an overpotential of 185 mV at 10 m A cm and maintains the high activity for over 1000 h in an acidic electrolyte via the adsorption evolution mechanism.
View Article and Find Full Text PDFSci Bull (Beijing)
January 2025
Hubei Biomass-Resource Chemistry and Environmental Biotechnology Key Laboratory, Hubei Provincial Engineering Research Center of Emerging Functional Coating Materials, School of Resource and Environmental Sciences, Wuhan University, Wuhan 430079, China. Electronic address:
The discontinuous fiber reinforced hydrogels are easy to fail due to the fracture of the fiber matrix during load-bearing. Here, we propose a novel strategy based on the synergistic reinforcement of interconnected natural fiber networks at multiple scales to fabricate hydrogels with extraordinary mechanical properties. Specifically, the P(AA-AM)/Cel (P(AA-AM), poly(acrylic acid-acrylamide); Cel, cellulose) hydrogel is synthesized by copolymerizing AA and AM on a substrate of paper with an interconnected hollow cellulose microfiber network.
View Article and Find Full Text PDFNeuroimage
January 2025
School of Psychology, University of Southampton, UK. Electronic address:
Authenticity has captivated scholars. But what is it? An emerging view considers it exaggerated favorability (self-enhancement), whereas traditional views regard it as self-accuracy and self-consistency. We tested these theoretical views by contrasting the authentic self with the presented self, a highly desirable representation.
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