Zwitterionic Modifications for Enhancing the Antifouling Properties of Poly(vinylidene fluoride) Membranes.

The development of effective antibiofouling membranes is critical for many scientific interests and industrial applications. However, the existing available membranes often suffer from the lack of efficient, stable, and scalable antifouling modification strategy. Herein, we designed, synthesized, and characterized alternate copolymers of p(MAO-DMEA) (obtained by reaction between poly(maleic anhydride-alt-1-octadecene) and N,N-dimethylenediamine) and p(MAO-DMPA) (obtained by reaction between poly(maleic anhydride-alt-1-octadecene) and 3-(dimethylamino)-1-propylamine) of different carbon space length (CSL) using a ring-opening zwitterionization.

Preparation of chitosan/hydroxyapatite substrates with controllable osteoconductivity tracked by AFM.

In this study, cell-material adhesive strength and cellular mechanical properties were measured using atomic force microscopy (AFM) to track cell attachment and osteogenic differentiation. First, chitosan substrates were treated with simulated body fluid (SBF) for various periods, resulting in substrates with different osteoconductivity. The X-ray diffraction (XRD), energy-dispersive X-ray spectroscopy (EDS) and in vitro tests revealed that the biomimeticity and osteoconductivity of substrates increased with increasing time of SBF treatment.

Bacterial resistance of self-assembled surfaces using PPOm-b-PSBMAn zwitterionic copolymer - concomitant effects of surface topography and surface chemistry on attachment of live bacteria.

Three well-defined diblock copolymers made of poly(sulfobetaine methacrylate) (poly(SBMA)) and poly(propylene oxide) (PPO) groups were synthesized by atom transfer radical polymerization (ATRP) method. They were physically adsorbed onto three types of surfaces having different topography, including smooth flat surface, convex surface, and indented surface. Chemical state of surfaces was characterized by XPS while the various topographies were examined by SEM and AFM.

Immobilization of naringin onto chitosan substrates by using ozone activation.

Ozone oxidation can easily produce peroxides containing active free radicals that can be used for the surface modification of biomaterials. This process is highly efficient and nontoxic. In this research, naringin, an HMG-CoA reductase inhibitor that can promote bone formation, was immobilized onto a chitosan film using ozone activation.

Using crosslinkable diacetylene phospholipids to construct two-dimensional packed beds in supported lipid bilayer separation platforms.

Separating and purifying cell membrane-associated biomolecules has been a challenge owing to their amphiphilic property. Taking these species out of their native lipid membrane environment usually results in biomolecule degradation. One of the new directions is to use supported lipid bilayer (SLB) platforms to separate the membrane species while they are protected in their native environment.

Surface self-assembled PEGylation of fluoro-based PVDF membranes via hydrophobic-driven copolymer anchoring for ultra-stable biofouling resistance.

Stable biofouling resistance is significant for general filtration requirements, especially for the improvement of membrane lifetime. A systematic group of hyper-brush PEGylated diblock copolymers containing poly(ethylene glycol) methacrylate (PEGMA) and polystyrene (PS) was synthesized using an atom transfer radical polymerization (ATRP) method and varying PEGMA lengths. This study demonstrates the antibiofouling membrane surfaces by self-assembled anchoring PEGylated diblock copolymers of PS-b-PEGMA on the microporous poly(vinylidene fluoride) (PVDF) membrane.

Interactions between chitosan and cells measured by AFM.

Chitosan, a biocompatible material that has been widely used in bone tissue engineering, is believed to have a high affinity to osteoblastic cells. This research is the first to prove this hypothesis. By using atomic force microscopy (AFM) with a chitosan-modified cantilever, quantitative evaluation of the interforce between chitosan and cells was carried out.

Immobilization of peptides by ozone activation to promote the osteoconductivity of PLLA substrates.

In this study, ozone treatment was applied to modify poly(L-lactic acid) (PLLA) with the intermediate reagent acryl-N-succinimide (ASI). Then, P15, the peptide related to the attachment and differentiation of osteoblastic cells, was reacted with ASI. Ozone activation successfully created peroxides on the surface of PLLA, which was quantitatively determined by the iodide method.

Monoclonal antibody-based quantitation of poly(ethylene glycol)-derivatized proteins, liposomes, and nanoparticles.

Covalent attachment of poly(ethylene glycol) (PEG) molecules to drugs, proteins, and liposomes is a proven technology for improving their bioavailability, safety, and efficacy. Qualitative and quantitative analysis of PEG-derivatized molecules is important for both drug development and clinical applications. We previously reported the development of a monoclonal IgM antibody (AGP3) to PEG.