Lianlei Wen

Bio: Lianlei Wen is an academic researcher from East China University of Science and Technology. The author has contributed to research in topics: Caprolactone & Micelle. The author has an hindex of 2, co-authored 4 publications receiving 18 citations.

Organocatalytic Ring-Opening Polymerization TowardPoly(γ-amide-ε-caprolactone)s with Tunable Lower CriticalSolution Temperatures

Abstract: γ-Amide-e-caprolactones including 7-oxo-N-propyloxepane-4-carboxamide (NNCL), N-isopropyl-7-oxooxepane-4-carboxamide (NICL), N,N-diethyl-7-oxooxepane-4-carboxamide (DECL), and 5-(pyrrolidine-1-carb

Antibacterial AIE polycarbonates endowed with selective imaging capabilities by adjusting the electrostaticity of the mixed-charge backbone

Abstract: Combining rapid microbial discrimination with antibacterial properties, multi-functional biomacromolecules allow the timely diagnosis and effective treatment of infectious diseases. Through a two-step approach involving organocatalytic ring-opening copolymerization and thiol-ene modification, aggregation-induced emission (AIE) polycarbonates decorated with tertiary amines were prepared. After being ionized using acetic acid, the obtained cationic AIE polycarbonate with excellent water solubility showed bacteria imaging capabilities and antibacterial activities toward both Gram-positive S. aureus and Gram-negative E. coli. It was indicated via scanning electron microscope images that the bactericidal mechanism involved membrane lysis, consistent with most cationic polymers. Through further co-grafting carboxyl and tertiary amine groups, mixed-charge AIE polycarbonates were obtained. The isoelectric points of such mixed-charge AIE polycarbonates could be simply tuned based on the grafting ratio of positive and negative moieties. Compared with the cationic AIE polycarbonate, mixed-charge AIE polycarbonates allowed the rapid and selective imaging of S. aureus, but not E. coli. The selectivity probably arose from the lower binding forces between the mixed-charge AIE polycarbonates and the low-negative-charge components of the E. coli surface. Therefore, these biodegradable polycarbonates, which integrated selective bacteria imaging and antibiotic abilities, potentially suggest a precision medicine approach for infectious diseases. The overall synthesis approach and mixed-charge AIE polycarbonates provide new references for the design and application of bio-related AIE polymers.

pH-Responsive Schizophrenic Diblock Copolymers Prepared by Polymerization-Induced Self-Assembly

Abstract: Polymerization-induced self-assembly (PISA) is used for the highly convenient and efficient preparation of ampholytic diblock copolymer nanoparticles directly in acidic aqueous solution. Cationic nanoparticles comprising a protonated polyamine stabilizer block and a hydrophobic polyacid core-forming block are formed at pH 2. Micelle inversion occurs at pH 10 to produce anionic nanoparticles with an ionized polyacid stabilizer block and a hydrophobic polyamine core-forming block. Macroscopic precipitation occurs at around pH 6-7, which lies close to the isoelectric point of this ampholytic diblock copolymer. Incorporation of fluorescein and rhodamine dye labels into the acid and amine blocks, respectively, leads to dual-color bifluorescent self-reporting pH-responsive nanoparticles.

A Versatile Strategy to Main Chain Sulfur/Selenium-Functionalized Polycarbonates by Macro-Ring Closure of Diols and Subsequent Ring-Opening Polymerization

Abstract: Herein, a new class of main chain functionalized aliphatic polycarbonates with sulfur/selenium functional groups on the backbone is reported. Sulfur/selenium-containing cyclic carbonate monomers (MR ) are designed and synthesized by enzyme-catalyzed intermolecular macro-ring closure of related diols. The proposed synthetic strategy is tolerant of other functionalities such as N-substituted groups. The ring opening polymerization (ROP) of MR occurs readily as a versatile route to generate a new family of main chain sulfur/selenium substituted aliphatic polycarbonates (PR) with predictable molecular weights (MW), narrow molecular-weight distribution and controlled copolymer composition. The resultant polymers can be oxidized and/or reduced by treatment with hydrogen peroxide (H2 O2 ) or dithiothreitol (DTT), highlighting their potential for applications in the stimuli-responsive field and inflammation/cancer targeting. With these desirable results, it is revealed that this versatile technique can provide a broad-reaching method to the next generation of innovative materials, especially, well-defined biodegradable chalcogen-based main chain functional biomaterials.