Poly(N,N-dimethylaminoethyl methacrylate) as a bioactive polyelectrolyte-production and properties

Poly(N,N-dimethylaminoethyl methacrylate) is a polyelectrolyte with many important chemical and physical properties and, above all, offers a wide range of interesting biological properties. Currently, research on this polymer is ongoing in several centres around the world. The process of polymerizing the monomer is not easy, as there are difficulties in obtaining a product with repeatable properties. This work collected and described most of the currently known and used polymerization methods of N,N-dimethylaminoethyl methacrylate, taking into account the type of method, the solvent used, the initiator, as well as the process temperature and the average molecular weight of the polymer obtained. The most important properties of the discussed polymer, such as solubility, bioactivity, hydrophilicity, cytotoxicity, conductivity, and thermal and hydrodynamic parameters, are discussed on the basis of the available scientific literature. This work aims, among other things, to increase the possibility of using poly(N,N-dimethylaminoethyl methacrylate) as a material in advanced practical applications. Therefore, various methods of applied use of the polymer in question have also been described so far. Copolymers of the N,N-dimethylaminoethyl methacrylate are now too large a collection to fit in a single publication. Therefore, only the most interesting examples were cited in this work.

A design approach for layer-by-layer surface-mediated siRNA delivery

The ability to coat scaffolds and wound dressings with therapeutic short interfering RNA (siRNA) holds much potential for applications in wound healing, cancer treatment, and regenerative medicine. Layer-by-layer (LbL) technology is an effective method to formulate polyelectrolyte thin films for local delivery of siRNA; however, the formation and efficacy of LbL coatings as drug delivery systems are highly contingent on the assembly conditions. Here, we investigate the effects of LbL assembly parameters on film composition and consequent siRNA-mediated gene knockdown efficiency in vitro. Films comprising poly(β-amino ester) (PBAE) and siRNA were built on polyglactin 910 (Vicryl) sutures consisting of poly(10% L-lactide, 90% glycolide). A fractional factorial design was employed, varying the following LbL assembly conditions: pH, ionic strength, PBAE concentration, and siRNA concentration. Effects of these parameters on PBAE loading, siRNA loading, their respective weight ratios, and in vitro siRNA-mediated knockdown were elucidated. The parameter effects were leveraged to create a rationally designed set of solution conditions that was predicted to give effective siRNA-mediated knockdown, but not included in any of the original experimental conditions. This level of knockdown with our rationally designed loading conditions (47%) is comparable to previous formulations from our lab while being simpler in construction and requiring fewer film layers, which could save time and cost in manufacturing. This study highlights the importance of LbL solution conditions in the preparation of surface-mediated siRNA delivery systems and presents an adaptable methodology for extending these electrostatically-assembled coatings to the delivery of other therapeutic nucleic acids. STATEMENT OF SIGNIFICANCE: Short interfering RNA (siRNA) therapeutics are powerful tools to silence aberrant gene expression in the diseased state; however, the clinical utility of these therapies relies on effective controlled delivery approaches. Electrostatic self-assembly through the layer-by-layer (LbL) process enables direct siRNA release from surfaces, but this method is highly dependent upon the specific solution conditions used. Here, we use a fractional factorial design to illustrate how these assembly conditions impact composition of siRNA-eluting LbL thin films. We then elucidate how these properties mediate in vitro transfection efficacy. Ultimately, this work presents a significant step towards understanding how optimization of assembly conditions for surface-mediated LbL delivery can promote transfection efficacy while reducing the processing and material required.

Coatings manufactured using magnetron sputtering technology to protect against infrared radiation for use in firefighter helmets

The aim of this study was to test the usefulness of magnetron sputtering technology to produce coatings on selected elements of a firefighter’s helmet to protect against infrared radiation (PN-EN 171 standard). The scope of research includes testing the deposition produced via magnetron sputtering of metallic and ceramic coatings on plastics, which are used to manufacture the components comprising the personal protection equipment used by firefighters. The UV-VIS, NIR used to research the permeation coefficients and reflections for light and infrared light and the emission spectrometry with ICP-AES used for the quantitative analysis of elements in metallic and ceramic coatings. Microstructural and micro-analytical testing of the coatings were performed using scanning electron microscopy (SEM). Measurements of the chemical compositions were conducted using energy-dispersive X-ray spectroscopy (EDS). The hardnesss of the coatings were tested using a indentation method, and the coating thicknesses were tested using a ellipsometry method.

Self-assembled antibacterial coating by N-halamine polyelectrolytes on a cellulose substrate

In this research, two N-halamine polymer precursors, a cationic homopolymer poly((3-acrylamidopropyl)trimethylammonium chloride) (CHP) and an anionic homopolymer poly(2-acrylamido-2-methylpropane sulfonic acid sodium salt) (AHP), have been successfully synthesized and coated onto cotton fabrics via a layer-by-layer (LbL) deposition technique. The coated cotton fabrics were characterized using scanning electron microscopy, X-ray photoelectron spectroscopy, and Fourier transform infrared spectroscopy. The biocidal efficacies of uncoated and coated cotton fabrics were evaluated against Staphylococcus aureus and Escherichia coli. The chlorinated swatches (CHP-Cl and AHP-Cl) inactivated 100% S. aureus and 99.73% E. coli O157:H7 in 30 min. Over 51% of the chlorine is retained after the equivalent of 50 machine washes. A skin stimulation test showed that CHP-Cl and AHP-Cl compounds have no irritation to rabbit skin, and so these swatches might be utilized for biomedical applications in the future. As an easy and efficient way of coating fabrics, the LbL deposition technique can broaden the use of N-halamine biocides in other polar substances as antimicrobial functional coatings.

Layer-by-Layer Surface Modification of Fruits with Edible Nano-Coatings

A new method for the surface modification of the surface of fruits based on the Layer-by-Layer (LbL) deposition of polyelectrolyte multilayers (PEM) is presented. Mangoes fruits were coated by sequential dipping in solutions of either Poly(diallyldimethylammonium chloride), (PDADMAC) or Poly(styrene sulfonate sodium salt) (PSS). After the deposition of only few polyelectrolyte layers, the skin of the fruits was changed from hydrophobic to hydrophilic as shown by contact angles measurements decreasing from 90 to 10. Fourier transform infrared spectroscopy (FTIR) was used to confirm the deposition of the PEM coating on the fruit which was then used as a matrix to load curcumin as model compound. Ultraviolet Visible (UV-Vis) spectroscopy was used to evaluate the amount of a curcumin loaded on the fruit surface as a function of the thickness of the film by indirect leaching in ethanol. This coating method provides a new approach to dope active compound on the fruit surface such as anti-oxidant, fragrance, color and other nutriment which could increase the market value of fruits.

The fabrication of nanocomposite thin films with TiO2 nanoparticles by the layer-by-layer deposition method for multifunctional cotton fabrics

A multilayer nanocomposite film composed of anatase TiO(2) nanoparticles was fabricated on cationically modified woven cotton fabrics by the layer-by-layer molecular self-assembly technique. For cationic surface charge, cotton fabrics were pre-treated with 2,3-epoxypropyltrimethylammonium chloride (EP3MAC) by a pad-batch method. Attenuated total reflectance Fourier transform infrared spectroscopy (FTIR), x-ray photoelectron spectroscopy (XPS) and scanning electron microscopy (SEM) were used to verify the presence of deposited nanolayers. Photocatalytic activities of the nanocomposite films were evaluated through the degradation of red wine pollutant. Nano-TiO(2) deposition enhanced the protection of cotton fabrics against UV radiation in comparison with the untreated cotton fabrics. Air permeability and whiteness value analysis was performed on the fabrics before and after the treatment with TiO(2) nanoparticles by the layer-by-layer deposition method. Tensile strength tests of the warp and weft yarns were performed to evaluate the effect of solution pH value changes during the alternate dipping procedures. For the first time the durability of the effect of the self-assembled multilayer films on the cotton fabric functional properties was analyzed after 10 and 20 washing cycles at 40 degrees C for 30 min.

Modifying of Cotton Fabric Surface with Nano-ZnO Multilayer Films by Layer-by-Layer Deposition Method

ZnO nanoparticle-based multilayer nanocomposite films were fabricated on cationized woven cotton fabrics via layer-by-layer molecular self-assembly technique. For cationic surface charge, cotton fabrics were pretreated with 2,3-epoxypropyltrimethylammonium chloride (EP3MAC) by pad-batch method. XPS and SEM were used to examine the deposited nano-ZnO multilayer films on the cotton fabrics. The nano-ZnO films deposited on cotton fabrics exhibited excellent antimicrobial activity against Staphylococcus aureus bacteria. The results also showed that the coated fabrics with nano-ZnO multilayer films enhanced the protection of cotton fabrics from UV radiation. Physical tests (tensile strength of weft and warp yarns, air permeability and whiteness values) were performed on the fabrics before and after the treatment with ZnO nanoparticles to evaluate the effect of layer-by-layer (LbL) process on cotton fabrics properties.