Novel Antimicrobial Coating on Silicone Contact Lens Using Glycidyl Methacrylate and Polyethyleneimine Based Polymers

Surface-grafted macromolecular nanowires with pedant fluorescein chromophores by dense non-aggregated nanoarchitectonics as versatile photoactive platforms

In this paper, we present a facile method of synthesis and modification of poly(glycidyl methacrylate) brushes with 6-aminofluorescein (6AF) molecules. Polymer brushes were obtained using surface-grafted atom transfer radical polymerization (SI-ATRP) and functionalized in the presence of triethylamine (TEA) acting both as a reaction catalyst and an agent preventing aggregation of chromophores. Atomic force microscopy (AFM), FTIR, X-ray photoelectron spectroscopy (XPS) were used to study the structure and formation of obtained photoactive platforms. UV-Vis absorption and emission spectroscopy and confocal microscopy were conducted to investigate photoactivity of chromophores within the macromolecular matrix. Owing to the simplicity of fabrication and good ordering of the chromophore in a thin nanometric layer, the proposed method may open new opportunities for obtaining light sensors, photovoltaic devices, or other light-harvesting systems.

UV-curable thiol-ene system for broadband infrared transparent objects

Conventional infrared transparent materials, including inorganic ceramic, glass, and sulfur-rich organic materials, are usually processed through thermal or mechanical progress. Here, we report a photo-curable liquid material based on a specially designed thiol-ene strategy, where the multithiols and divinyl oligomers were designed to contain only C, H, and S atoms. This approach ensures transparency in a wide range spectrum from visible light to mid-wave infrared (MWIR), and to long-wave infrared (LWIR). The refractive index, thermal properties, and mechanical properties of samples prepared by this thiol-ene resin were characterized. Objects transparent to LWIR and MWIR were fabricated by molding and two-photon 3D printing techniques. We demonstrated the potential of our material in a range of applications, including the fabrication of IR optics with high imaging resolution and the construction of micro-reactors for temperature monitoring. This UV-curable thiol-ene system provides a fast and convenient alternative for the fabrication of thin IR transparent objects.

A Novel Strategy for Creating an Antibacterial Surface Using a Highly Efficient Electrospray-Based Method for Silica Deposition

Adhesion of bacteria on biomedical implant surfaces is a prerequisite for biofilm formation, which may increase the chances of infection and chronic inflammation. In this study, we employed a novel electrospray-based technique to develop an antibacterial surface by efficiently depositing silica homogeneously onto polyethylene terephthalate (PET) film to achieve hydrophobic and anti-adhesive properties. We evaluated its potential application in inhibiting bacterial adhesion using both Gram-negative Escherichia coli (E. coli) and Gram-positive Staphylococcus aureus (S. aureus) bacteria. These silica-deposited PET surfaces could provide hydrophobic surfaces with a water contact angle greater than 120° as well as increased surface roughness (root mean square roughness value of 82.50 ± 16.22 nm and average roughness value of 65.15 ± 15.26 nm) that could significantly reduce bacterial adhesion by approximately 66.30% and 64.09% for E. coli and S. aureus, respectively, compared with those on plain PET surfaces. Furthermore, we observed that silica-deposited PET surfaces showed no detrimental effects on cell viability in human dermal fibroblasts, as confirmed by MTT (3-(4,5-dimethylthiazol-2-yl)-2,5 diphenyl tetrazolium bromide and live/dead assays. Taken together, such approaches that are easy to synthesize, cost effective, and efficient, and could provide innovative strategies for preventing bacterial adhesion on biomedical implant surfaces in the clinical setting.

Facile transformation of carboxymethyl cellulose beads into hollow composites for dye adsorption

Novel millimeter hollow microspheres were fabricated from carboxymethyl cellulose microspheres and polyethyleneimine using glutaraldehyde as a crosslinking agent. The hollow microspheres prepared with different polyethyleneimine usages and different polyethyleneimine treatment time were investigated deeply and characterized via SEM-EDX, FT-IR, and BET surface area analysis. It was shown that polyethyleneimine could break the coordination bonds between the carboxyl and Al (III) in carboxymethyl cellulose microspheres, leading to the formation of hollow structures. Most importantly, the usage and treatment time of polyethyleneimine can distinctly tailor the structure of the carboxymethyl cellulose microspheres, resulting in the formation of different hollow microspheres with varied shell thickness and size. Most importantly, we found that the prepared hollow microspheres have excellent adsorption performance toward targeted methyl blue under testing conditions. By virtue of the large accessible amount of -NH₂ groups and its unique hollow structure, this type of millimeter hollow microspheres have broad application prospects in the treatment of emerging contaminants in wastewater.

Effective and biocompatible antibacterial surfaces via facile synthesis and surface modification of peptide polymers

It is an urgent need to tackle drug-resistance microbial infections that are associated with implantable biomedical devices. Host defense peptide-mimicking polymers have been actively explored in recent years to fight against drug-resistant microbes. Our recent report on lithium hexamethyldisilazide-initiated superfast polymerization on amino acid N-carboxyanhydrides enables the quick synthesis of host defense peptide-mimicking peptide polymers. Here we reported a facile and cost-effective thermoplastic polyurethane (TPU) surface modification of peptide polymer (DLL: BLG = 90 : 10) using plasma surface activation and substitution reaction between thiol and bromide groups. The peptide polymer-modified TPU surfaces exhibited board-spectrum antibacterial property as well as effective contact-killing ability in vitro. Furthermore, the peptide polymer-modified TPU surfaces showed excellent biocompatibility, displaying no hemolysis and cytotoxicity. In vivo study using methicillin-resistant Staphylococcus aureus (MRSA) for subcutaneous implantation infectious model showed that peptide polymer-modified TPU surfaces revealed obvious suppression of infection and great histocompatibility, compared to bare TPU surfaces. We further explored the antimicrobial mechanism of the peptide polymer-modified TPU surfaces, which revealed a surface contact-killing mechanism by disrupting the bacterial membrane. These results demonstrated great potential of the peptide-modified TPU surfaces for practical application to combat bacterial infections that are associated with implantable materials and devices.

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A convenient surface modification of peptide polymer 90 : 10 DLL : BLG to enable material surfaces antibacterial properties.

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The modified thermoplastic polyurethane (TPU) surfaces show board-spectrum antibacterial performance and excellent biocompatibility both in vitro and in vivo.

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The contact-killing surfaces demonstrate great potential for practical application to combat bacterial infections associated with implantable materials and devices.

Poly(glycidyl methacrylate) macromolecular assemblies as biocompatible nanocarrier for the antimicrobial lysozyme

The antimicrobial lysozyme (Lys) was electrostatically incorporated to negatively charged crosslinked poly(glycidyl methacrylate) (c-PGMA) macromolecular assemblies. The resulting material was characterized by AFM, infrared spectra, water contact angle measurements and the staining with the primary amino specific dye fluorescamine. c-PGMA nanoparticles were successfully loaded with Lys reaching ratios of 27.3 ± 4.0 and 22.5 ± 1.7 mg Lys/g polymer for c-PGMA suspensions and functionalized glass substrates, respectively. Lys-loaded c-PGMA caused clear inhibition zones on S. aureus and E. coli in comparison to neat c-PGMA. c-PGMA functionalized surfaces were intrinsically resistant to colonization, but the incorporation of Lys added resistance to bacterial attachment and allowed keeping surfaces clean of bacterial cells for both strains. A relatively rapid release (24 h) of Lys was observed at physiological pH (7.4). In addition, c-PGMA functionalized substrates could be reloaded several times without losing capacity. c-PGMA macromolecular assemblies did not display cytotoxicity to human dermal fibroblasts as shown in 24 h MTT assays. This work demonstrated that c-PGMA assemblies display durable antibacterial activity, biocompatibility, and full reloading capacity with antimicrobial peptides. c-PGMA functionalized materials have potential application as nanocarriers for anti-infective uses.

Synthesis and Characterization of Cationic Dendrimer-PDMS Hybrids

A modular strategy for the synthesis of dendron-linear polymer hybrids comprised of a flexible polydimethylsiloxane (PDMS) midblock with cationic 2,2-bis(hydroxymethyl)propionic acid (bis-MPA) dendron end groups is developed. The invention of a scalable methodology to access quaternary ammonium carboxylate building blocks and their direct use in esterification chemistry enables rapid access to cationic bis-MPA dendrons. The convergent click coupling of highly charged dendrons to hydrophobic PDMS chain-ends gives a 12-membered family of hybrids that are comprised of different dendron generations (G1-3) and quaternary ammonium alkyl chain lengths (C4 , C8 , C12 , C16 ). This provides a library of materials with variable hydrophobicity, charge density, and chain-end valency. The physical behavior of the dendron-linear PDMS hybrid copolymers significantly changes after introduction of the cationic dendron end-groups and leads to soft-solid materials as a result of inhibited chain mobility. These PDMS-dendron hybrids are expected to behave as surface-active antimicrobial additives in bulk cross-linked silicone systems.

Benchtop Preparation of Polymer Brushes by SI-PET-RAFT: The Effect of the Polymer Composition and Structure on Inhibition of a Pseudomonas Biofilm

We report a high-throughput method for producing surface-tethered polymeric brushes on glass substrates via surface-initiated photoinduced electron transfer-reversible addition-fragmentation chain transfer polymerization (SI-PET-RAFT). Due to its excellent oxygen tolerance, SI-PET-RAFT allows brush growth using low reagent volumes (30 μL) without prior degassing. An initial 28 homopolymer brush library was successfully prepared and screened with respect to their antifouling performance. The high-throughput approach was further exploited to expand the library to encompass statistical, gradient, and block architectures to investigate the effect of monomer composition and distribution using two monomers of disparate performance. In this manner, the degree of attachment from Gram-negative Pseudomonas aeruginosa (PA) bacterial biofilms could be tuned between the bounds set by the homopolymer brushes.