The Highly Durable Antibacterial Gel-like Coatings for Textiles.

Hospital-acquired infections are considered a priority for public health systems, which poses a significant burden for society. High-touch surfaces of healthcare centers, including textiles, provide a suitable environment for pathogenic bacteria to grow, necessitating incorporating effective antibacterial agents into textiles. This paper introduces a highly durable antibacterial gel-like solution, Silver Shell finish, which contains chitosan-bound silver chloride microparticles. The study investigates the coating's environmental impact, health risks, and durability during repeated washing. The structure of the Silver Shell finish was studied using Transmission Electron Microscopy (TEM) and Energy-Dispersive X-ray Spectroscopy (EDX). TEM images showed a core-shell structure, with chitosan forming a protective shell around groupings of silver micro-particles. Field Emission Scanning Electron Microscopy (FESEM) demonstrated the uniform deposition of Silver Shell on the surface of fabrics. AATCC Test Method 100 was employed to quantitatively analyze the antibacterial properties of fabrics coated with silver microparticles. Two types of bacteria, Staphylococcus aureus (S. aureus) and Escherichia coli (E. coli) were used in this study. The antibacterial results showed that after 75 wash cycles, a 100% reduction for both S. aureus and E. coli in the coated samples using crosslinking agents was observed. The coated samples without a crosslinking agent exhibited a 99.88% and 99.81% reduction for S. aureus and E. coli after 50 washing cycles. AATCC-147 was performed to investigate the coated samples' leaching properties and the crosslinking agent's effect against S. aureus and E. coli. All coated samples demonstrated remarkable antibacterial efficacy even after 75 wash cycles.

Reversible Binding Interfaces Made of Microstructured Polymer Brushes.

The polymer brush architecture of the end-tethered polymer molecules is one of the most widely used efficient methods to regulate interfacial interactions in colloidal systems found in live matter and manufactured materials. Emerging applications of polymer brush structures require solutions to new tasks in the control of interfacial interactions. The rapid development of live cell manufacturing relies on scalable and efficient cell harvesting methods. Stimuli-responsive surfaces made of surface-grafted poly(N-isopropylacrylamide) (PNIPAM) can bind and detach the adherent cell upon changes in temperature and have been used for cell growth and harvesting. The applications are limited by the requirement to satisfy a range of PNIPAM coating characteristics that depend on the dimensions of the integrin complex in the cell membrane and the basal surface. The analysis of the microstructured surfaces, when adhesive and disjoining functions of the microdomains are decoupled, shows that many limitations of PNIPAM one-component coatings can be avoided by using a much broader range of structural characteristics of the microstructured interfaces composed of alternating disjoining PNIPAM domains and adhesive polymeric domains with cell-affinity functional groups. Temperature-controlled reversible adhesion to such microstructured interfaces is studied here experimentally with model systems of solid spherical particles and by employing simulations for solid and soft membranes interacting with the microstructured surfaces to mimic interactions with soft and solid disk-like particles.

Strategy for Nonenzymatic Harvesting of Cells via Decoupling of Adhesive and Disjoining Domains of Nanostructured Stimulus-Responsive Polymer Films.

The nanostructured polymer film introduces a novel mechanism of nonenzymatic cell harvesting by decoupling solid cell-adhesive and soft stimulus-responsive cell-disjoining areas on the surface. The key characteristics of this architecture are the decoupling of adhesion from detachment and the impermeability to the integrin protein complex of the adhesive domains. This surface design eliminates inherent limitations of thermoresponsive coatings, namely, the necessity for the precise thickness of the coating, grafting or cross-linking density, and material of the basal substrate. The concept is demonstrated with nanostructured thermoresponsive films made of cell-adhesive epoxy photoresist domains and cell-disjoining poly(N-isopropylacrylamide) brush domains.

CeO2 Nanoparticle-Containing Polymers for Biomedical Applications: A Review.

The development of advanced composite biomaterials combining the versatility and biodegradability of polymers and the unique characteristics of metal oxide nanoparticles unveils new horizons in emerging biomedical applications, including tissue regeneration, drug delivery and gene therapy, theranostics and medical imaging. Nanocrystalline cerium(IV) oxide, or nanoceria, stands out from a crowd of other metal oxides as being a truly unique material, showing great potential in biomedicine due to its low systemic toxicity and numerous beneficial effects on living systems. The combination of nanoceria with new generations of biomedical polymers, such as PolyHEMA (poly(2-hydroxyethyl methacrylate)-based hydrogels, electrospun nanofibrous polycaprolactone or natural-based chitosan or cellulose, helps to expand the prospective area of applications by facilitating their bioavailability and averting potential negative effects. This review describes recent advances in biomedical polymeric material practices, highlights up-to-the-minute cerium oxide nanoparticle applications, as well as polymer-nanoceria composites, and aims to address the question: how can nanoceria enhance the biomedical potential of modern polymeric materials?

Control of Vancomycin Activity through the Encapsulation and Controlled Release from a Propargyl Acrylate-Poloxamer Nanocomposite System.

Vancomycin is a potent antibacterial drug that suffers from poor bioavailability due to its poor water solubility and relatively high molecular weight. Consequently, the application of vancomycin to treat bacteria-induced disease is limited. In this study, the ability of a temperature-stimulated propargyl acrylate-poloxamer nanocomposite (PAPN) system to encapsulate and release vancomycin is investigated. A controllable encapsulation and release system can be used to not only increase and prolong the bioavailability of vancomycin but also activate vancomycin with a temperature change. The PAPN system was prepared using an emulsion polymerization of propargyl acrylate followed by a surface decoration with a poloxamer at a precisely controlled grafting density. The activity of the PAPN system loaded with vancomycin is compared to that of the free drug and unmodified propargyl acrylate nanoparticles. It is shown that the activity of the PAPN system loaded with vancomycin is comparable to that of a freshly prepared, free-floating vancomycin solution. Upon storage, the activity of the free vancomycin in solution decreases, while the PAPN system loaded with vancomycin retains its high activity. Additionally, the PAPN system is able to effectively encapsulate and deactivate vancomycin until heated above a lower critical solution temperature (LCST). At temperatures above the LCST, the PAPN system releases vancomycin restoring the activity of the drug.

Nanoceria: Metabolic interactions and delivery through PLGA-encapsulation.

Cerium oxide nanoparticles (nanoceria) have recyclable antioxidative activity. It has numerous potential applications in biomedical engineering, such as mitigating damage from burns, radiation, and bacterial infection. This mitigating activity is analogous to that property of metabolic enzymes such as superoxide dismutase (SOD) and catalase - scavengers of reactive oxygen species (ROS). Therefore, nanoceria can protect cells from environmental oxidative stress. This therapeutic effect prompted studies of nanoceria and metabolic enzymes as a combination therapy. The activity and structure of SOD, catalase, and lysozyme were examined in the presence of nanoceria. A complementary relationship between SOD and nanoceria motivated the present work, in which we explored a method for simultaneous delivery of SOD and nanoceria. The biocompatibility and tunable degradation of poly(lactic-co-glycolic acid) (PLGA) made it a candidate material for encapsulating both nanoceria and SOD. Cellular uptake studies were conducted along with a cytotoxicity assay. The antioxidative properties of PLGA-nanoceria-SOD particles were verified by adding H2O2 to cell culture and imaging with fluorescent markers of oxidative stress. Our results suggest that PLGA is a suitable encapsulating carrier for simultaneous delivering nanoceria and SOD together, and that this combination effectively reduces oxidative stress in vitro.

Anti-inflammatory coatings of hernia repair meshes: A pilot study.

The current prevalence of postoperative chronic pain from hernioplasty procedures employing polymer mesh is close to 30%. Most of the researchers agree that oxidative stress, resulting from the release of oxidants and enzymes during acute inflammatory response, is a key factor in the development of posthernioplasty complications. This results in both the decrease of the biomechanical properties and stiffening of the polymer fibers of the mesh, leading to chronic pain. Moreover, enhanced activity of inflammatory cells can lead to an excessive deposition of connective tissue around the implant. In this study polypropylene hernia repair meshes coated with vitamin E (α-tocopherol), a known antioxidant, were prepared and characterized. The absorption isotherm of vitamin E on the mesh was characterized and a release profile study yielded a promising results, showing sustained release of the drug over a 10-day period. An animal study was conducted, and histological analysis five weeks after implantation exhibited a reduced host tissue response for a modified mesh as compared to a plain mesh, as evidenced by a higher mature collagen to immature collagen ratio, as well as lower level of fatty infiltrates, neovascularization and fibrosis in the case of modified mesh. These results support the use of α-tocopherol as a potential coating in attempt to reduce the extent of postoperative inflammation, and thereby improve long-term outcomes of hernioplasty. © 2017 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 106B: 589-597, 2018.

Albumin-Assisted Method Allows Assessment of Release of Hydrophobic Drugs From Nanocarriers.

Polymeric nanoparticles have been extensively studied as drug delivery vehicles both in vitro and in vivo for the last two decades. In vitro methods to assess drug release profiles usually utilize degradation of nanoparticles in aqueous medium, followed by the measurement of the concentration of the released drug. This method, however, is difficult to use for drugs that are poorly water soluble. In this study, a protocol for measuring drug release kinetic using albumin solution as the medium is described. Albumin is a major blood transport protein, which mediates transport of many lipid soluble compounds including fatty acids, hormones, and bilirubin. The use of a dialysis-based system utilizing albumin dialysate solution allows hydrophobic drug release from a diverse set of drug delivery modalities is demonstrated. The method using liposomes and PLGA nanoparticles as drug carriers, and two model hydrophobic drugs, 17ß-estradiol, and dexamethasone is validated.

In vitro study on the deterioration of polypropylene hernia repair meshes.

Despite the relative safety of the procedure, hernia repairs are often associated with chronic post-operative pain. Although this complication has been linked among others to mesh deterioration, details of the processes that lead this deterioration are still unknown. This work aims to bridge this gap by analyzing the chemical, physical and structural alterations in hernia repair meshes exposed to oxidative stress in vitro. Here, we developed a methodology to characterize effect of oxidation stress on structure and properties of polymeric hernia repair meshes. It was shown that structural changes in polypropylene meshes exposed to oxidative stress may involve formation of cross-links between the polymer chains, chain scissions, and hydrogen bonds between the carboxyl groups, which are formed in the material during the oxidation. These effects result in mesh stiffening, ultimately leading to chronic post-operative pain. Moreover, we demonstrated that Composix meshes are more vulnerable to the oxidative stress when compared with UltraPro meshes. © 2017 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 106B: 2225-2234, 2018.

Climbing ability of teneral and sclerotized adult bed bugs and assessment of adhesive properties of the exoskeletal fluid using atomic force microscopy.

We observed that teneral adults (<1 h post-molt) of Cimex lectularius L. appeared more adept at climbing a smooth surface compared to sclerotized adults. Differences in climbing ability on a smooth surface based on sclerotization status were quantified by measuring the height to which bed bugs climbed when confined within a glass vial. The average maximum height climbed by teneral (T) bed bugs (n = 30, height climbed = 4.69 cm) differed significantly (P< 0.01) from recently sclerotized (RS) bed bugs (n = 30, height climbed = 1.73 cm at ~48 h post molt), sclerotized group 1 (S1) bed bugs (n = 30, S1 = 2.42 cm at >72 h), and sclerotized group 2 (S2) bed bugs (n = 30, height climbed = 2.64 cm at >72 h post molt). When heights from all climbing events were summed, teneral bed bugs (650.8 cm climbed) differed significantly (P< 0.01) from recently sclerotized (82 cm climbed) and sclerotized (group 1 = 104.6 cm climbed, group 2 = 107.8 cm climbed) bed bugs. These findings suggested that the external surface of teneral bed bug exoskeletons possess an adhesive property. Using atomic force microscopy (AFM), we found that adhesion force of an exoskeletal (presumably molting) fluid decreased almost five-fold from 88 to 17 nN within an hour of molting. Our findings may have implications for laboratory safety and the effectiveness of bed bug traps, barriers, and biomimetic-based adhesives.

Antioxidant Activity of SOD and Catalase Conjugated with Nanocrystalline Ceria.

Interactions of nanoparticles with biological matter-both somatically and in nature-draw scientists' attention. Nanoparticulate systems are believed to be our saviors, acting as versatile drug delivery vehicles. However, they can also cause life-threatening bodily damage. One of the most important properties of nanocrystalline cerium dioxide is its antioxidant activity, which decreases the abundance of reactive oxygen species during inflammation. In this paper, we report on synergistic effects of inorganic cerium oxide (IV) nanoparticles conjugated with the antioxidative enzymes superoxide dismutase and catalase on scavenging oxygen and nitrogen radicals.

Novel Antibacterial Coating on Orthopedic Wires To Eliminate Pin Tract Infections.

Novel approaches to the prevention of microbial infections after the insertion of orthopedic external fixators are in great demand because of the extremely high incidence rates of such infections, which can reach up to 100% with longer implant residence times. Monolaurin is an antimicrobial agent with a known safety record that is broadly used in the food and cosmetic industries; however, its use in antimicrobial coatings of medical devices has not been studied in much detail. Here, we report the use of monolaurin as an antibacterial coating on external fixators for the first time. Monolaurin-coated Kirschner wires (K-wires) showed excellent antibacterial properties against three different bacterial strains, i.e., methicillin-sensitive Staphylococcus aureus (MSSA), methicillin-resistant Staphylococcus aureus (MRSA), and Staphylococcus epidermidis Approximately 6.0-log reductions of both planktonic and adherent bacteria were achieved using monolaurin-coated K-wires, but monolaurin-coated K-wires did not show any observable cytotoxicity with mouse osteoblast cell cultures. Overall, monolaurin-coated K-wires could be promising as potent antimicrobial materials for orthopedic surgery.

Relationship between Targeting Efficacy of Liposomes and the Dosage of Targeting Antibody Using Surface Plasmon Resonance.

Surface plasmon resonance (SPR) was used in this research to investigate the targeting efficacy (i.e., the binding affinity) of antibody-modified liposomes. The results indicated that liposomes modified by targeting antibodies exhibited an increase in apparent binding affinity, a result attributed to the avidity effect. More specifically, the targeting effect improved as the surface density of the targeting antibody increased, an increase primarily attributed to the decrease of the dissociation rate. However, this trend stopped when the surface density reached a threshold of approximately 1.5 × 10(8) antibody/mm(2). This surface density was found to be quite consistent regardless of the liposome size and the type of targeting antibody. In addition, a traditional cell binding experiment was conducted to confirm the saturation point obtained from SPR.

Proteins conjugated to poly(butyl cyanoacrylate) nanoparticles as potential neuroprotective agents.

Poly(butyl cyanoacrylate) (PBCA) nanoparticles (NPs) can penetrate blood-brain barrier providing the means for drug delivery to the central nervous system. Here, we study attachment of superoxide dismutase (SOD) and anti-glutamate N-methyl D-aspartate receptor 1 (NR1) antibody to PBCA NPs with the ultimate goal to design neuroprotective therapeutics for treatment of secondary spinal cord injury. Synthesis of monodispersed, ∼200 nm-diameter PBCA NPs was performed using polymerization at pH 2.0 with Dextran 70,000 as the stabilizer. Sulfo-HSAB spacers were used to covalently attach SOD and NR1 antibodies to the dextran-coated NPs. The prepared protein-NP conjugates possessed SOD activity and were capable of binding to rat cerebellar neurons. Thus, SOD and NR1 antibodies may be simultaneously attached to PBCA NPs while retaining at least a fraction of enzymatic activity and receptor-binding ability. The conjugates showed neuroprotective efficacy in vitro with rat cerebellar cell cultures challenged by superoxide.

Enzyme-nanoparticle conjugates for biomedical applications.

Enzymes hold a great promise as therapeutic agents because of their unique specificity and high level of activity. Yet, clinically important enzyme drugs are for less common than conventional low molecular weight drugs due to a number of disadvantages. Most important among these are poor stability, potential immunogenicity, and potential systemic toxicity. Recent developments in synthesis and characterization of nanoparticles and exciting novel properties of some classes of nanomaterials have boosted interest in the potential use of nanoparticles as carriers of enzyme drugs. In certain cases, use of enzymes attached to nanoparticles can help to overcome some of the above problems and improve the prospects of clinical applications of enzyme drugs. Here, we review recent data on the use of nanoparticles as carriers for several clinically important enzyme drugs and discuss advantages and potential limitations of such constructs. While promising preliminary results were obtained with regard to their performance in vitro and in some animal models, further investigations and clinical trials, as well as addressing regulatory issues, are warranted to make these delivery systems suitable for clinical applications.

Cigarette smoke extract stimulates interleukin-8 production in human airway epithelium and is attenuated by superoxide dismutase in vitro.

BACKGROUND: Cigarette smoke exposure (CSE) results in extensive inflammation in the upper and lower airways. Reactive oxygen species, such as superoxide, have been shown to be potent mediators of this inflammation. METHODS: Mucosal biopsy specimens were collected from patients undergoing sinonasal surgery and were used as a source of primary epithelial cells. Human sinonasal epithelial (HSNE) cells and were isolated from sinus tissue, maintained in culture, and ultimately treated with varying concentrations of CSE with or without free superoxide dismutase (SOD). Supernatants and cell lysates were examined for the proinflammatory cytokine interleukin (IL)-8. Similar experiments were performed using normal human bronchial epithelial (NHBE) cell lines. RESULTS: CSE induces both secretion and intracellular production of the proinflammatory cytokine IL-8 by HSNE cells in a dose-dependent manner. Furthermore, this up-regulation can be suppressed by SOD. CSE induces secretion of IL-8 in NHBEs that is also suppressed by SOD. CONCLUSION: Inflammation in the airway after CSE can be blocked by SOD in this in vitro model. The ability to attenuate CSE-induced inflammation with SOD could provide a therapeutic/preventative approach for individuals with cigarette smoke exposure.