The generation of polymer brushes by surface-initiated controlled radical polymerization (SI-CRP) techniques has become a powerful approach to tailor the chemical and physical properties of interfaces and has given rise to great advances in surface and interface engineering. Polymer brushes are defined as thin polymer films in which the individual polymer chains are tethered by one chain end to a solid interface. Significant advances have been made over the past years in the field of polymer brushes. This includes novel developments in SI-CRP, as well as the emergence of novel applications such as catalysis, electronics, nanomaterial synthesis and biosensing. Additionally, polymer brushes prepared via SI-CRP have been utilized to modify the surface of novel substrates such as natural fibers, polymer nanofibers, mesoporous materials, graphene, viruses and protein nanoparticles. The last years have also seen exciting advances in the chemical and physical characterization of polymer brushes, as well as an ev...

Surface-Initiated Controlled Radical Polymerization: State-of-the-Art, Opportunities, and Challenges in Surface and Interface Engineering with Polymer Brushes

Radical Polymerization and Copper(0) Mediated Polymerization): From Fundamentals to Bioapplications Cyrille Boyer,*,†,‡ Nathaniel Alan Corrigan,‡ Kenward Jung,‡ Diep Nguyen,‡ Thuy-Khanh Nguyen,‡ Nik Nik M. Adnan,†,‡ Susan Oliver,†,‡ Sivaprakash Shanmugam,‡ and Jonathan Yeow†,‡ †Australian Centre for Nanomedicine, and ‡Centre for Advanced Macromolecular Design (CAMD), School of Chemical Engineering, University of New South Wales, Sydney 2052, Australia

Copper-Mediated Living Radical Polymerization (Atom Transfer Radical Polymerization and Copper(0) Mediated Polymerization): From Fundamentals to Bioapplications

Nucleic acid separation is an increasingly important tool for molecular biology. Before modern technologies could be used, nucleic acid separation had been a time- and work-consuming process based on several extraction and centrifugation steps, often limited by small yields and low purities of the separation products, and not suited for automation and up-scaling. During the last few years, specifically functionalised magnetic particles were developed. Together with an appropriate buffer system, they allow for the quick and efficient purification directly after their extraction from crude cell extracts. Centrifugation steps were avoided. In addition, the new approach provided for an easy automation of the entire process and the isolation of nucleic acids from larger sample volumes. This review describes traditional methods and methods based on magnetic particles for nucleic acid purification. The synthesis of a variety of magnetic particles is presented in more detail. Various suppliers of magnetic particles for nucleic acid separation as well as suppliers offering particle-based kits for a variety of different sample materials are listed. Furthermore, commercially available manual magnetic separators and automated systems for magnetic particle handling and liquid handling are mentioned.

Magnetic particles for separation and purification of nucleic acids

Carboxymethyl chitosan: Properties and biomedical applications.

The impact-induced deposition of Al13 clusters with icosahedral structure on Ni(0 0 1) surface was studied by molecular dynamics (MD) simulation using Finnis–Sinclair potentials. The incident kinetic energy (Ein) ranged from 0.01 to 30 eV per atom. The structural and dynamical properties of Al clusters on Ni surfaces were found to be strongly dependent on the impact energy. At much lower energy, the Al cluster deposited on the surface as a bulk molecule. However, the original icosahedral structure was transformed to the fcc-like one due to the interaction and the structure mismatch between the Al cluster and Ni surface. With increasing the impinging energy, the cluster was deformed severely when it contacted the substrate, and then broken up due to dense collision cascade. The cluster atoms spread on the surface at last. When the impact energy was higher than 11 eV, the defects, such as Al substitutions and Ni ejections, were observed. The simulation indicated that there exists an optimum energy range, which is suitable for Al epitaxial growth in layer by layer. In addition, at higher impinging energy, the atomic exchange between Al and Ni atoms will be favourable to surface alloying.

Nuclear instruments and methods in physics research section B : beam interactions with materials and atoms

Silver deposited carboxymethyl chitosan-grafted magnetic nanoparticles as dual action deliverable antimicrobial materials.

Cells capture and antimicrobial effect of hydrophobically modified chitosan coating on Escherichia coli.

Bactericidal magnetic nanoparticles were prepared by complexing iodine with poly(N-vinylpyrrolidone) (PVP) grown at the surface of silica coated magnetic nanoparticles (MNPs) via surface-initiated atom transfer radical polymerization (SI-ATRP). Approximately, 10 mg of iodine could be loaded onto one gram of the PVP-grafted MNPs to form bactericidal MNPs@PVP-I. At a concentration of 5 g L-1, MNPs@PVP-I could achieve 100% bactericidal rate for both Gram-negative Escherichia coli and Gram-positive Staphylococcus aureus with a concentration of ∼1 × 1010 CFU mL-1 within 3 min. After being used for killing the bacteria in solution, the bactericidal rate of the MNPs@PVP-I decreased to <10% due to the consumption of iodine. The bactericidal rate could be tuned back to 100% when the used MNPs@PVP-I was recharged in a 15 g L-1 iodine solution for 12 h. The as-prepared bactericidal MNPs@PVP-I could be reused at least 4 times with 100% bactericidal rate by repeatedly recharging it with iodine.

Bactericidal magnetic nanoparticles with iodine loaded on surface grafted poly(N-vinylpyrrolidone)

Hydrophobically modified chitosan (HMCS), synthesized by reacting dodecyl aldehyde with chitosan (CS) has good hemostatic properties and can, by means of its hydrophobic tail, coagulate blood cells. In this work, the ability of synthesized HMCS to coagulate Escherichia coli cells was demonstrated. In order to facilitate the removal of coagulated E. coli cells using an applied magnetic field, HMCS was grafted on to the surface of magnetic nanoparticles (MNPs). Such modified MNPs interacted with Gram-negative bacteria such as E. coli by means of strong hydrophobic forces between the hydrophobic tails of HMCS and outer membrane of E. coli. The highest E. coli removal capacity achieved by MNPs@HMCS was 1.38 × 108 cells/mg. The characterization of CS, HMCS, CS/HMCS grafted MNPs (MNPs@CS, MNPs@HMCS) were carried out by Fourier transform infrared spectroscopy (FTIR), elemental analysis (EA), scanning electron microscopy (SEM), and thermogravimetric analysis (TGA). The degree of deacetylation (DDA) and the degree...

Duc-Thang Vo

Papers

Silver deposited carboxymethyl chitosan-grafted magnetic nanoparticles as dual action deliverable antimicrobial materials.

Cells capture and antimicrobial effect of hydrophobically modified chitosan coating on Escherichia coli.

Bactericidal magnetic nanoparticles with iodine loaded on surface grafted poly(N-vinylpyrrolidone)

Hydrophobically Modified Chitosan-Grafted Magnetic Nanoparticles for Bacteria Removal

Antimicrobial sponge prepared by hydrophobically modified chitosan for bacteria removal.