A5019744998- Chemical Synthesis and Analysis
- Advanced biosensing and bioanalysis techniques
- Supramolecular Self-Assembly in Materials
- Advanced Polymer Synthesis and Characterization
- Crystallization and Solubility Studies
- biodegradable polymer synthesis and properties
- X-ray Diffraction in Crystallography
- Pickering emulsions and particle stabilization
- Genomics and Phylogenetic Studies
- Analytical Chemistry and Chromatography
- RNA and protein synthesis mechanisms
- Polymer Surface Interaction Studies
- Zeolite Catalysis and Synthesis
- Mesoporous Materials and Catalysis
- Clay minerals and soil interactions
- Force Microscopy Techniques and Applications
- Lipid Membrane Structure and Behavior
- Protein Structure and Dynamics
- Dendrimers and Hyperbranched Polymers
- Advanced Biosensing Techniques and Applications
- Hydrogels: synthesis, properties, applications
- Biocrusts and Microbial Ecology
- Electrospun Nanofibers in Biomedical Applications
- Near-Field Optical Microscopy
- Synthetic Organic Chemistry Methods
Harbin Institute of Technology
2024-2025
Louisiana State University
2017-2024
Lawrence Berkeley National Laboratory
2023-2024
University of California, Riverside
2018-2023
Louisiana State University Agricultural Center
2020
University of Electronic Science and Technology of China
2020
University of Auckland
2019
University of Akron
2013
University of Washington
2000
Solution self-assembly of coil-crystalline diblock copolypeptoids has attracted increasing attention due to its capability form hierarchical nanostructures with tailorable morphologies and functionalities. While the N-substituent (or side chain) structures are known affect crystallization polypeptoids, their roles in dictating solution not fully understood. Herein, we designed synthesized two types copolypeptoids, i.e., poly(
Halloysite nanotubes (HNTs), naturally occurring and environmental benign clay nanoparticles, have been successfully functionalized with amphiphilic polypeptoid polymers by surface-initiated polymerization methods investigated as emulsion stabilizers toward oil spill remediation. The hydrophilicity lipophilicity balance (HLB) of the grafted polypeptoids was shown to affect wettability HNTs their performance for oil-in-water emulsions. having relatively high hydrophobic content (HLB =...
Crystallization-driven self-assembly (CDSA) of amphiphilic polymers into well-defined nanoscopic structures with different morphologies and functionalities has attracted increasing attention. Here, we investigate the CDSA coil–comb-shaped diblock copolypeptoids, namely, poly(N-methyl glycine)-b-poly(N-decyl glycine) (PNMG-b-PNDG), in dilute methanol solution using X-ray/neutron scattering conjunction cryogenic transmission electron microscopy techniques. A series PNMG-b-PNDGs were...
Interfacial ring-opening polymerizations (iROP) of α-amino-acid derived N-thiocarboxyanhydrides (NTAs) in hexanes or heptane suspension using soluble primary amine initiators have been demonstrated to produce polypeptides with controlled molecular weight and low-to-moderate distribution under mild conditions. The NTA monomers were shown significantly enhanced moisture thermal stability relative N-carboxyanhydrides (NCAs), resulting long shelf life allowing the polymerization occur...
A synthetic procedure was developed to prepare dual acid–base catalysts on a single platform. Mesoporous SBA-15 derivatized using known grafting chemistry via the following steps: (1) addition of Boc-protected 3-aminopropyltriethoxysilane; (2) controlled use UV/ozonolysis selectively remove exterior groups; (3) decoration sites freed in Step 2 with 3-mercaptopropyltriethoxysilane; (4) selective oxidation mercaptan groups sulfonic acid; and (5) pyrolytic deprotection amine. The resulting...
The ability to engineer synthetic polymers with the same structural precision as biomacromolecules is crucial enable de novo design of robust nanomaterials biomimetic function. Peptoids, poly(N-substituted) glycines, are a highly controllable bio-inspired polymer family that can assemble into variety functional, crystalline nanostructures over wide range sequences. Extensive investigation on molecular packing in these lattices has been reported; however, many key atomic-level details...
Utilization of 4-dibenzocyclooctynol (DIBO) as an initiator for the ring-opening polymerization ε-caprolactone yields well-defined, high molecular weight poly(ε-caprolactone) end functionalized with DIBO (DIBO–PCL). Nanofibers bearing reactive groups were generated via electrospinning and post-fabrication azide-tethered molecules.
Particle stabilized emulsions provide an environmentally friendly alternative to the chemical dispersion of oil in event a spill over water. Mineral clay particles present abundance marine environments adsorb at oil–water interfaces forming stable emulsion droplets. We describe carbonization these clays using sustainable biopolymer, chitosan, optimize wetting characteristics and generate extremely 150 μm clay-armored droplets model crude (Anadarko). In addition such droplet stabilization,...
Peptoid polymers with sequence-defined side chains are observed to self-assemble into a variety of structures spanning nanometer and micron scales. We explored diblock copolypeptoid, poly(N-decylglycine)10-block-poly(N-2-(2-(2-methoxyethoxy)ethoxy)-ethylglycine)10 (abbreviated as Ndc10-Nte10), which forms crystalline nanofibers nanosheets evidenced by recent cryo-transmission electron microscopy, atomic force X-ray diffraction, calorimetry. Using all-atom molecular dynamics simulations, we...
Transposition of a new 5.4-kb transposon, Tn4811, Streptomyces lividans to the melC operon antibioticus on plasmid pIJ702 was discovered. The nucleotide sequence this copy which contained an imperfect (9 11 bp) terminal inverted repeat, five putative coding sequences for oxidoreductase and its transcription regulator, three transposition-related proteins, determined. SLP- strains S. one (A) while SLP2+ additional (B) SLP2 plasmid. at insertion junctions Tn4811 were Copy B lacked 41 bp from...
We investigated the effect of cyclic chain topology on molecular ordering and thermal stability comb-shaped polypeptoid thin films silicon (Si) substrates. Cyclic linear poly(N-decylglycine) (PNDG) bearing long n-decyl side chains were synthesized by ring-opening polymerization N-decylglycine-derived N-carboxyanhydrides. When spin-coated subjected to annealing at temperatures above melting temperature (T > Tm), PNDG exhibited significantly enhanced against melt-induced dewetting than...
Poly(α-peptoid)s, a structural isomer to polypeptides, have recently attracted significant amount of scientific attention. However, the molecular mechanism behind thermal response this class polymers is unknown. Here, two polypeptoids in aqueous solutions was studied by different methodologies, including dynamic light scattering, IR spectroscopies, NMR, etc. Our studies focused on with identical alkyl side chain compositions, but architecture; i.e., cyclic and linear. Aqueous linear present...
Peptoids are highly biocompatible pseudopeptidic polyglycines with designable substituents on the nitrogen atoms. The therapeutic and drug-carrying potential of these materials requires a fundamental understanding their interactions lipid bilayers. In this work, we use amphiphilic polypeptoids up to 100 monomeric units where significant fraction (26%) atoms functionalized decyl groups (hydrophobes) that insert into bilayer through hydrophobic effect. These hydrophobically modified (HMPs)...
Amphiphilic molecules that can crystallize often form molecularly thin nanosheets in aqueous solutions. The possibility of atomic-scale corrugations these structures has not yet been recognized. We have studied the self-assembly amphiphilic polypeptoids, a family bio-inspired polymers self-assemble into various crystalline nanostructures. Atomic-scale structure crystals systems inferred using both X-ray diffraction and electron microscopy. Here we use cryogenic microscopy to determine...
The hydrophobic effect of alkyl group insertion into phospholipid bilayers is exploited in modifying and modulating vesicle structure. We show that amphiphilic polypeptoids (peptide mimics) with
Cellular functions of membrane proteins are strongly coupled to their structures and aggregation states in the cellular membrane. Molecular agents that can induce fragmentation lipid membranes highly sought after as they potentially useful for extracting native environment. Toward this goal, we investigated synthetic liposome using hydrophobe-containing polypeptoids (HCPs), a class facially amphiphilic pseudo-peptidic polymers. A series HCPs with varying chain lengths hydrophobicities have...
We present the results of a crystallographic analysis, magnetic characterization including neutron powder diffraction, and theoretical assessment K2ReI6 prepared using solvent reactions. crystallizes in space group P21/n with an inversion center. Magnetic measurements sample indicate dominant antiferromagnetic coupling Curie–Weiss temperature θW = −63.3(1) K, effective moment ∼2.64 μB/Re but show weak ferromagnetism ordered at ∼24 K. Neutron diffraction indicates long-range order Re spins...
The melC operon of Streptomyces antibioticus is unstable, undergoing frequent spontaneous deletions. All the delta mutants analyzed also lost 2-kb V1 DNA, which contained two open reading frames (ORFs) homologous to ORF4 (a putative oxidoreductase gene) and ORF5 AraC-type regulatory Tn4811. ORFs may constitute an accessory unit a different transposon.
We investigated the temperature-dependent structural evolution of thermoreversible triblock terpolypeptoid hydrogels, namely poly(