Antimicrobial Coatings for Medical Textiles via Reactive Organo-Selenium Compounds.

Bleached and cationized cotton fabrics were chemically modified with reactive organoselenium compounds through the nucleophilic aromatic substitution (SNAr) reaction, which allowed for organo-selenium attachment onto the surface of cotton fabrics via covalent bonds and, in the case of the cationized cotton fabric, additional ionic interactions. The resulting textiles exhibited potent bactericidal activity against S. aureus (99.99% reduction), although only moderate activity was observed against E. coli. Fabrics treated with reactive organo-selenium compounds also exhibited fungicidal activities against C. albicans, and much higher antifungal activity was observed when organo-selenium compounds were applied to the cationized cotton in comparison to the bleached cotton. The treatment was found to be durable against rigorous washing conditions (non-ionic detergent/100 °C). This paper is the first report on a novel approach integrating the reaction of cotton fabrics with an organo-selenium antimicrobial agent. This approach is attractive because it provides a method for imparting antimicrobial properties to cotton fabrics which does not disrupt the traditional production processes of a textile mill.

Comparative Efficacy in Preventing Plaque Formation around Pit and Fissure Sealants: A Clinical Trial.

AIM: The purpose of this study is to compare the clinical performance of an organo-selenium-containing pit and fissure sealant with that of a selenium-free sealant for clinical retention and prevention of plaque and caries development around the sealants. MATERIALS AND METHODS: Following an in vitro study confirming the antimicrobial effect of an organo-selenium-containing pit/fissure sealant [DenteShield™ (DS)], 120 adolescents (7-20 years old) at varying caries risk status had DS sealant applied to a single tooth on the left or the right side of the dentition and UltraSeal™ XT Plus (UXT) on a corresponding tooth on the opposite side. Sealants' assessment was performed quarterly for 1 year for clinical retention, plaque, and caries formation around the sealant. Each sealant lost was replaced but considered as a failure in further analysis. McNemar's test was used to statistically analyze the outcome variables at each assessment time point. RESULTS: While 7% and 12% plaque growth was observed around the UXT sealant at 9th and 12th months, respectively, DS exhibited 100% prevention of plaque growth. Both sealants exhibited 100% caries prevention. Clinical retention did not significantly differ between DS and UXT at all assessment time points except at 12 months when DS showed statistically significantly (p < 0.001) better retention (96%) than UXT (81%). CONCLUSION: In this study, while both sealants are equally effective in caries prevention, DS completely prevented plaque growth around it with better clinical retention than UXT that offered only limited protection against plaque growth. CLINICAL SIGNIFICANCE: Being antimicrobial, DS pit and fissure sealant may be the best sealant option for patients whose caries risk status is due to poor oral hygiene.

The ability of quaternary ammonium groups attached to a urethane bandage to inhibit bacterial attachment and biofilm formation in a mouse wound model.

For proper wound healing, control of bacteria or bacterial infections is of major importance. While caring for a wound, dressing material plays a key role as bacteria can live in the bandage and keep re-infecting the wound. They do this by forming biofilms in the bandage, which slough off planktonic bacteria and overwhelm the host defense. It is thus necessary to develop a wound dressing that will inhibit bacterial growth. This study examines the effectiveness of a polyurethane foam wound dressing bound with polydiallyl-dimethylammonium chloride (pDADMAC) to inhibit the growth of bacteria in a wound on the back of a mouse. This technology does not allow pDADMAC to leach away from the dressing into the wound, thereby preventing cytotoxic effects. Staphylococcus aureus, Pseudomonas aeruginosa and Acinetobacter baumannii were chosen for the study to infect the wounds. S. aureus and P. aeruginosa are important pathogens in wound infections, while A. baumannii was selected because of its ability to acquire or upregulate antibiotic drug resistance determinants. In addition, two different isolates of methicillin-resistant S. aureus (MRSA) were tested. All the bacteria were measured in the wound dressing and in the wound tissue under the dressing. Using colony-forming unit (CFU) assays, over six logs of inhibition (100%) were found for all the bacterial strains using pDADMAC-treated wound dressing when compared with control-untreated dressing. The CFU assay results obtained with the tissues were significant as there were 4-5 logs of reduction (100%) of the test organism in the tissue of the pDADMAC-covered wound versus that of the control dressing-covered wound. As the pDADMAC cannot leave the dressing (like other antimicrobials), this would imply that the dressing acts as a reservoir for free bacteria from a biofilm and plays a significant role in the development of a wound infection.

A study on the ability of quaternary ammonium groups attached to a polyurethane foam wound dressing to inhibit bacterial attachment and biofilm formation.

Bacterial infection of acute and chronic wounds impedes wound healing significantly. Part of this impediment is the ability of bacterial pathogens to grow in wound dressings. In this study, we examined the effectiveness of a polyurethane (PU) foam wound dressings coated with poly diallyl-dimethylammonium chloride (pDADMAC-PU) to inhibit the growth and biofilm development by three main wound pathogens, Staphylococcus aureus, Pseudomonas aeruginosa, and Acinetobacter baumannii, within the wound dressing. pDADMAC-PU inhibited the growth of all three pathogens. Time-kill curves were conducted both with and without serum to determine the killing kinetic of pDADMAC-PU. pDADMAC-PU killed S. aureus, A. baumannii, and P. aeruginosa. The effect of pDADMAC-PU on biofilm development was analyzed quantitatively and qualitatively. Quantitative analysis, colony-forming unit assay, revealed that pDADMAC-PU dressing produced more than eight log reduction in biofilm formation by each pathogen. Visualization of the biofilms by either confocal laser scanning microscopy or scanning electron microscopy confirmed these findings. In addition, it was found that the pDADMAC-PU-treated foam totally inhibited migration of bacteria through the foam for all three bacterial strains. These results suggest that pDADMAC-PU is an effective wound dressing that inhibits the growth of wound pathogens both within the wound and in the wound dressing.

Selenium Bandages and Cotton Cloth That Kill Microorganisms in Wounds.

INTRODUCTION: The material of a bandage plays an important role in wound management. Microorganisms can colonize the dressing and release toxins, which create dead cells in the wound. This allows the microorganisms to bind the dead cells and infect the wound. Thus, a dressing is needed that kills bacteria in the bandage. To combat health care-associated infections, antimicrobial treatment of medical textiles, such as gauze, uniforms, curtains, bed sheets, gowns, and masks, is required. Besides, antimicrobial resistance is another major problem of this century. Antibacterial overuse has contributed to drug-resistant bacteria. To combat these two problems, we synthesized new organo-selenium compounds that can be attached to the cotton of the dressing. We then used an in vivo wound model, which allowed us to measure the effectiveness of selenium attached to a cotton dressing, to prevent bacteria from infecting a wound. MATERIALS AND METHODS: Organo-selenium was attached to cotton fabric, resulting in a fabric with 0.1% selenium covalently attached to it. Staphylococcus aureus (as well as methicillin-resistant S. aureus [MRSA]), Stenotrophomonas maltophilia, Enterococcus faecalis, Staphylococcus epidermidis, and Pseudomonas aeruginosa were chosen for the wound infection study. All the bacteria were enumerated in the wound dressing and in the wound tissue under the dressing. Wounds were made on the backs of mice. The material was used as a bandage over the wound. Bacteria were injected into the wound under the bandage. The amount of bacteria in the wound after 5 days was determined. A similar study was performed using dressing material that was soaked in phosphate buffered saline at 37 °C for 3 months before use. RESULTS: Cotton dressing with selenium attached showed complete inhibition (7 logs, as compared with control dressing) of different bacterial strains, in both the dressing and "the tissue" of the wound. Similar results were obtained using selenium cotton dressing that was soaked for 3 months before use. Control cotton with no selenium showed complete infiltration of bacteria into the wound and the dressing. In addition, a study was performed under Food and Drug Administration standard methods to show the ability of the selenium to kill bacteria in the fabric, using material that was washed 5 times in detergent. This also showed complete killing of bacteria in the fabric. CONCLUSIONS: The results show that the selenium remains in the dressing after washing and is able to completely protect the wound from bacterial infection. In the selenium bandage, no bacteria were found in the bandage or the wound after 5 days.

Alginate/organo-selenium composite hydrogel beads: Dye adsorption and bacterial deactivation.

Post-COVID-19, the risk and spread of germs, coupled with wastewater contamination, have become critical concerns. Wastewater contains waterborne bacteria and various contaminants like dye molecules, threatening water safety. Traditional methods address pollutant removal or pathogen inactivation separately, but a dual-action solution is increasingly essential. This study presents alginate/selenium composite hydrogel beads capable of simultaneously removing dyes and deactivating bacteria. Fabricated by dropping suspension droplets into a calcium ion bath, these beads were tested for dye adsorption and antibacterial efficacy. Beads with 50 wt% organo­selenium demonstrated the highest methylene blue (MB) adsorption capacity and nearly 100 % deactivation efficiency against Pseudomonas aeruginosa, while those with 20 wt% showed no significant improvement. Mechanistic studies reveal that organo­selenium induces stacking effects and reduces surface charges, enhancing MB adsorption and antibacterial performance. The alginate/organo­selenium composite hydrogel beads offer a potential effective and sustainable solution for tackling the complex issue of wastewater pollutants.

Complete Growth Inhibition of Pseudomonas aeruginosa by Organo-Selenium-Incorporated Urinary Catheter Material.

To further investigate the inhibition of Pseudomonas aeruginosa's in vitro growth and biofilm formation by an organo-selenium-incorporated polyurethane (PU) catheter material. P. aeruginosa, Staphylococcus aureus, and Candida albicans were incubated in vitro with organo-selenium and control polyurethane catheter materials in the presence of glutathione. Growth was evaluated by a colony-forming-unit (CFU) count and visualized with confocal laser scanning microscopy. Two different PU catheter materials were used. Using tin-catalyzed PU catheter material, complete inhibition of S. aureus was seen at 1% selenium (Se), whereas no inhibition was seen for P. aeruginosa at up to 3.0% Se. Whereas, using a thermoplastic PU catheter material, 1.5% Se and 2% Se organo-selenium caused several logs of growth inhibition of P. aeruginosa, and 2.5% selenium, incorporation showed complete inhibition (8 logs). Samples with lower than 1.5% selenium did not show adequate growth inhibition for P. aeruginosa. Similar in vitro growth inhibition was achieved against a multidrug-resistant C. albicans strain. It was concluded that optimal inhibition of P. aeruginosa in vitro growth and biofilm formation occurs with 2.5% selenium incorporated as organo-selenium in a thermoplastic PU catheter material. These results suggest that reduced incidence of CAUTIs (catheter associated urinary tract infections) with P. aeruginosa and other bacteria and fungi can be achieved by using organo-selenium-incorporated catheters.

Efficacy of organo-selenium-incorporated urinary catheter tubing for in vitro growth inhibition of E. coli, K. pneumoniae, P. aeruginosa, and H. influenzae.

PURPOSE: Catheter-associated urinary tract infections are of significant medical burden in cost, morbidity, and mortality. Experimental selenium-coated medical devices have demonstrated non-toxic in vitro and in vivo antimicrobial activity. While antimicrobial-coated catheters have shown efficacy in preventing CAUTIs, selenium has not been tested in this context. The purpose of this in vitro study is to evaluate selenium-incorporated urinary catheters for inhibition of uropathogenic bacterial growth and biofilm formation. METHODS: Urinary catheters incorporated with 1% organo-selenium and standard (uncoated) catheters were incubated in vitro with E. coli, K. pneumoniae, P. aeruginosa, H. influenzae, and combinations of these bacteria. Growth was evaluated by colony-forming unit count and visualized with confocal laser and scanning electron microscopy. Organo-selenium catheter material integrity was also tested by soaking the tubing in phosphate-buffered saline for 12 weeks at 37 °C. RESULTS: Organo-selenium-incorporated catheters demonstrated total reduction (100%) of in vitro bacterial growth and biofilm formation for E. coli, K. pneumoniae, H. influenzae, and a combination of these species when compared to control. P. aeruginosa growth was inhibited by approximately 4 logs (99.99%). Complete inhibition of E. coli growth was maintained after long-term phosphate-buffered saline soaking. CONCLUSION: The results demonstrate that organo-selenium was stably incorporated into catheter tubing and inhibited bacterial attachment, growth, and biofilm formation for multiple uropathogenic organisms. Furthermore, long-term soaking of organo-selenium tubing in phosphate-buffered saline did not show any decline in bacterial growth inhibition or biofilm formation. These findings suggest that organo-selenium-incorporated catheters may be advantageous in preventing catheter-associated urinary tract infections and warrant further in vivo and clinical evaluation.

Minocycline and Diacetyl Minocycline Eye Drops Reduce Ocular Neovascularization in Mice.

Purpose: To evaluate the efficacy of minocycline and a novel, modified minocycline analogue that lacks antimicrobial action, diacetyl minocycline (DAM), on choroidal neovascularization (CNV) in mice of both sexes. Methods: CNV was induced via laser injury in female and male C57BL/6J mice. Minocycline, DAM, or saline was administered via topical eye drops twice a day for 2 weeks starting the day after laser injury. CNV volume was measured using immunohistochemistry labeling and confocal microscopy. Results: Minocycline reduced lesion volume by 79% (P ≤ 0.0004) in female and male mice. DAM reduced lesion volume by 73% (P ≤ 0.001) in female and male mice. There was no significant difference in lesion volume between minocycline and DAM treatment groups or between female and male mice. Conclusions: Both minocycline and DAM eye drops significantly reduced laser-induced CNV lesion volume in female and male mice. While oral tetracyclines have been shown to mitigate pathologic neovascularization in both preclinical studies and clinical trials, the present data are the first to suggest that tetracycline derivatives may be effective to reduce pathologic CNV when administered via topical eye drops. However, the action is unrelated to antimicrobial action. Targeted delivery of these medications via eye drops may reduce the potential for systemic side effects. Translational Relevance: Topical administration of minocycline and/or DAM via eye drops may represent a novel therapeutic strategy for disorders involving pathologic CNV.

An organoselenium compound inhibits Staphylococcus aureus biofilms on hemodialysis catheters in vivo.

Colonization of central venous catheters (CVCs) by pathogenic bacteria leads to catheter-related bloodstream infections (CRBSIs). These colonizing bacteria form highly antibiotic-resistant biofilms. Staphylococcus aureus is one of the most frequently isolated pathogens in CRBSIs. Impregnating CVC surfaces with antimicrobial agents has various degrees of effectiveness in reducing the incidence of CRBSIs. We recently showed that organoselenium covalently attached to disks as an antibiofilm agent inhibited the development of S. aureus biofilms. In this study, we investigated the ability of an organoselenium coating on hemodialysis catheters (HDCs) to inhibit S. aureus biofilms in vitro and in vivo. S. aureus failed to develop biofilms on HDCs coated with selenocyanatodiacetic acid (SCAA) in either static or flowthrough continuous-culture systems. The SCAA coating also inhibited the development of S. aureus biofilms on HDCs in vivo for 3 days. The SCAA coating was stable and nontoxic to cell culture or animals. This new method for coating the internal and external surfaces of HDCs with SCAA has the potential to prevent catheter-related infections due to S. aureus.

The Potential Antiviral Effects of Selenium Nanoparticles and Coated Surfaces.

Modern epidemics quickly spread across borders and continents with devastating effects on both human health and the world economy. This issue is made worse by the various ways that infections are spread, including through aerosol, droplets, and fomites. The antibacterial qualities of various surface materials and coatings have been the subject of much research. However, the antiviral activity of metal coatings can be heavily influenced by imbalances in metal distribution and the presence of other metal impurities. As such, there is interest in developing novel surface coatings that can reduce the transmission of active viral particles in healthcare facilities. In recent years, the non-metals, such as selenium and nanoparticles, have acquired greater interest from the medical and scientific community for their antiviral surface activity. In this review, we will discuss the cellular and physiological functions of selenium in mammalian cells and against viral infections. We then discuss the mechanism behind selenium coated surfaces and their efficacy against bacterial infections. Lastly, we examine the antiviral activity of selenium, and the potential antiviral activity of selenium nanoparticles and coatings.

Effects of Dexamethasone on DNA Synthesis in Lens Epithelial Cells Are Dependent on Cell Type and Growth Factor.

PURPOSE: To determine the factors that influence the ability of dexamethasone (dex) to inhibit or stimulate the growth of lens epithelial cells. METHOD: Different growth factors with or without dex (10-6 M) were added to quiescent cultures of two clones of Nakano mouse lens epithelial cells (NK11) in serum-free medium. DNA synthesis was then measured after 8-12 hours by the incorporation of tritiated thymidine. RESULTS: Dex was found to both stimulate and inhibit mitogen-induced 3H-thymidine incorporation into the DNA of cultured mouse lens epithelial cells. Enhancement or repression by dex was found to depend on the growth factor used to stimulate the quiescent cell. EGF and insulin were consistently inhibited with dex. Basic fibroblast growth factor (bFGF) and retinoblastoma-derived growth factor (RbDGF) were both enhanced and inhibited by dex, depending on the growth factor concentration and the cell clone used for the experiment. Additionally, RbDGF protects against the dex inhibition of insulin stimulation, but not the inhibition of EGF stimulation. Progesterone, an inhibitor of the activation of the glucocorticoid receptor, blocks the dex inhibitory effect on the EGF and insulin stimulation of DNA synthesis. The ability of progesterone to affect the dex inhibition is consistent with the dex receptor modulating DNA synthesis. The dex effect on DNA synthesis, either stimulatory or inhibitory, was still seen if dex was added as late as 10 hours after the growth factor. CONCLUSIONS: The study demonstrated that dex reduces the overall growth and activity of lens epithelial cells in vitro. This result provides insight into the risk of developing posterior subcapsular cataracts (PSC) in patients on oral glucocorticoid therapy. Understanding the basic mechanisms by which steroids mediate lens cell growth may provide the ability to more accurately predict who will develop PSC. The present studies show the difference in the effect of dex from lens cell to lens cell, but, more importantly, suggest a pattern of dependent variables that might prove useful in such predictions.

Organo-selenium containing dental sealant inhibits biofilm formation by oral bacteria.

OBJECTIVE: Dental plaque is a complex structure (called a biofilm) that is produced by a community of oral bacteria. As microorganisms accumulate in the oral cavity, bacteria can assemble into biofilms that protect them from antibiotics and disinfectants, which contribute to dental cavities and oral infections that acts as the seed for further infections throughout the body. Therefore, there is great interest in developing dental sealants that can effectively eliminate biofilms formed from an assortment of oral bacteria species. METHODS: In previous papers, it was shown that both in vivo and in vitro use of organo-selenium dental sealants have the potential to be an effective method for preventing dental caries and plaque formation. However, our previous in vitro study only examined the effect of the organo-selenium sealants on Streptococcus mutans and salivarius. Since that time, this organo-selenium sealant has been changed to improve its curing time. RESULTS: We showed a selenium containing sealant (SeLECT-DefenseTM) can completely eliminate biofilm formation on the sealant at selenium concentrations of 0.25% and higher, by S. salivarius, S. sanguinis, or S. mutans, individually or in combination. This selenium containing sealant can also completely inhibit the same bacteria from growing under the sealant, while control sealant cannot. The selenium containing sealant was tested for stability and it was found to still kill these same bacteria after soaking for the equivalent of one year in PBS (pH 7.4). It was also found that the combination of the three bacteria were also killed by the selenium sealant, thus ruling out potential synergism of the bacteria in forming resistance. SIGNIFICANCE: The following study showed that this modified selenium dental sealant effectively eliminates species of bacteria both on and under the dental sealant.

An in vitro Study of Betadine's Ability to Eliminate Live Bacteria on the Eye: Should It Be Used for Protection against Endophthalmitis?

BACKGROUND: Povidone-iodide (Betadine) is an antiseptic that is applied topically and has many uses in the medical community, such as in wound care and pre- and post-operative surgical procedures. This study was done to measure the effectiveness of Betadine solutions in inhibiting the growth of Gram-negative and Gram-positive bacteria. METHODS: The ability of 2.5 and 10% Betadine solutions to inhibit bacterial growth was measured against Staphylococcus aureus, Staphylococcus epidermidis, Pseudomonas aeruginosa, and Acinetobacter baumannii. We grew the bacteria independently and together to simulate a hospital environment. RESULTS: All the bacteria showed zones of inhibition. However, discs were also tested for live bacteria using the colony-forming unit assay. Complete killing was only seen for S. aureus with the 10% Betadine solution. All other bacteria showed growth on the disc. CONCLUSIONS: This study showed several things. First, the zone of inhibition assay does not give an accurate assessment of antimicrobial properties when used alone and should be followed by a colony-forming unit assay. Second, 2.5% and 5% Betadine do not have effective antimicrobial properties against any of the bacteria tested, and 10% Betadine is only effective against S. aureus and not effective against the other bacteria tested.

The Use of an Organo-Selenium Peptide to Develop New Antimicrobials That Target a Specific Bacteria.

This study examines the use of a covalently selenium-bonded peptide and phage that binds to the Yersinia pestis F1 antigen for the targeting and killing of E. coli expressing this surface antigen. Using a Ph.D.-12 phage-display library for affinity selection of the phage which would bind the F1 antigen of Y. pestis, a phage displaying a peptide that binds the F1 antigen with high affinity and specificity was identified. Selenium was then covalently attached to the display phage and the corresponding F1-antigen-binding peptide. Both the phage and peptides with selenium covalently attached retained their binding specificity for the Y. pestis F1 antigen. The phage or peptide not labeled with selenium did not kill the targeted bacteria, while the phage or peptide labeled with selenium did. In addition, the seleno-peptide, expressing the F1 targeting sequence only, killed cells expressing the F1 antigen but not the parent strain that did not express the F1 antigen. Specifically, the seleno-peptide could kill eight logs of bacteria in less than two hours at a 10-µM concentration. These results demonstrate a novel approach for the development of an antibacterial agent that can target a specific bacterial pathogen for destruction through the use of covalently attached selenium and will not affect other bacteria.

Doxycycline's effect on ocular angiogenesis: an in vivo analysis.

PURPOSE: To determine the in vivo effect of doxycycline on choroidal angiogenesis and pterygium growth by using a choroidal neovascular (CNV) murine model, a directed in vivo angiogenesis assay (DIVAA) and a pterygium murine model. DESIGN: Experimental study. PARTICIPANTS: Three murine models were investigated with 4 mice minimum per group and 22 maximum per group. METHODS: Mice received water with or without doxycycline. For the CNV, the neovascular lesion volume was determined in choroid-retinal pigment epithelial flat mounts using confocal microscopy 7 days after laser induction. For DIVAA, silicone capsules containing 10,000 human pterygium epithelial cells were implanted in the flanks of mice subcutaneously. After 11 days, neovascularization (NV) was quantified using spectrofluorometry after murine tail-vein injection of fluorescein isothiocyanate-labeled dextran. A pterygium epithelial cell model was developed by injecting 10,000 human pterygium epithelial cells in the nasal subconjunctival space in athymic nude mice. Doxycycline was started on day 6 at 50 mg/kg per day; corneal lesions that resulted from the injections were compared at days 6 and 15. MAIN OUTCOME MEASURES: The Student t-test was used to evaluate the data for the CNV and DIVAA models and histologic preparations were used to evaluate pterygia lesions. RESULTS: There was significantly less NV and lesion volume with doxycycline taken in drinking water versus plain water. With doxycycline treatment, the laser-induced CNV showed a maximal 66% decrease in choroidal blood vessel volume (P< or =0.008) and the DIVAA showed a 30% reduction of blood vessel growth and migration (P<0.004). Histologic preparations demonstrated that pterygium cell lesions regressed when mice were administered doxycycline for 9 days. CONCLUSIONS: Doxycycline significantly inhibited angiogenesis in 3 murine models. The most dramatic effect was found in the CNV model followed by the pterygia epithelial cell DIVAA model. The anterior segment pterygium model also showed regression histologically. This suggests that doxycycline may be successful as an adjunctive treatment for CNV and pterygia in humans; clinical trials would be necessary to determine if there is a benefit.

What a study of pterygia teaches us about the cornea? Molecular mechanisms of formation.

Experiments were carried out in the early 1990s to investigate the cell types involved in a pterygium and to determine a possible mechanism of formation. Our first experiments used monoclonal antibodies to keratins and an associated protein (vimentin), to look at the cells that compose a pterygium. These experiments demonstrated that a pterygium is the result of an abnormal limbal basal epithelial stem cell that moves onto Bowman's layer and brings about the dissolution of this layer. More importantly, these data showed that the clear corneal epithelial cells in front of the pterygium also contained these abnormal limbal cells, which we named the pterygium cell. This demonstrated that when a pterygium is removed, a wide area of what appears to be normal epithelium must be removed to inhibit reoccurrence of the growth. Later experiments using expressed sequence tag analysis of an un-normalized unamplified complementary DNA library from surgically removed pterygia were compared with normal cornea and confirmed the role of the epithelial cells in this growth. The gene expression studies also showed that genes involved in cellular migration are stimulated, and this led to studies on polyamine analogs as inhibitors of pterygial migration. Immunohistochemical studies with antibodies to matrix metalloproteinases (MMPs) showed that it is the pterygium cell that produces the MMPs that dissolve Bowman's layer resulting in the growth stimulation of stromal fibroblasts. This led to experiments on the use of MMP inhibitors to inhibit the growth of pterygia.

Organo-Selenium-Containing Polyester Bandage Inhibits Bacterial Biofilm Growth on the Bandage and in the Wound.

The dressing material of a wound plays a key role since bacteria can live in the bandage and keep re-infecting the wound, thus a bandage is needed that blocks biofilm in the bandage. Using an in vivo wound biofilm model, we examined the effectiveness of an organo-selenium (OS)-coated polyester dressing to inhibit the growth of bacteria in a wound. Staphylococcus aureus (as well as MRSA, Methicillin resistant Staph aureus), Stenotrophomonas maltophilia, Enterococcus faecalis, Staphylococcus epidermidis, and Pseudomonas aeruginosa were chosen for the wound infection study. All the bacteria were enumerated in the wound dressing and in the wound tissue under the dressing. Using colony-forming unit (CFU) assays, over 7 logs of inhibition (100%) was found for all the bacterial strains on the material of the OS-coated wound dressing and in the tissue under that dressing. Confocal laser scanning microscopy along with IVIS spectrum in vivo imaging confirmed the CFU results. Thus, the dressing acts as a reservoir for a biofilm, which causes wound infection. The same results were obtained after soaking the dressing in PBS at 37 °C for three months before use. These results suggest that an OS coating on polyester dressing is both effective and durable in blocking wound infection.

Organoselenium coating on cellulose inhibits the formation of biofilms by Pseudomonas aeruginosa and Staphylococcus aureus.

Among the most difficult bacterial infections encountered in treating patients are wound infections, which may occur in burn victims, patients with traumatic wounds, necrotic lesions in people with diabetes, and patients with surgical wounds. Within a wound, infecting bacteria frequently develop biofilms. Many current wound dressings are impregnated with antimicrobial agents, such as silver or antibiotics. Diffusion of the agent(s) from the dressing may damage or destroy nearby healthy tissue as well as compromise the effectiveness of the dressing. In contrast, the antimicrobial agent selenium can be covalently attached to the surfaces of a dressing, prolonging its effectiveness. We examined the effectiveness of an organoselenium coating on cellulose discs in inhibiting Pseudomonas aeruginosa and Staphylococcus aureus biofilm formation. Colony biofilm assays revealed that cellulose discs coated with organoselenium completely inhibited P. aeruginosa and S. aureus biofilm formation. Scanning electron microscopy of the cellulose discs confirmed these results. Additionally, the coating on the cellulose discs was stable and effective after a week of incubation in phosphate-buffered saline. These results demonstrate that 0.2% selenium in a coating on cellulose discs effectively inhibits bacterial attachment and biofilm formation and that, unlike other antimicrobial agents, longer periods of exposure to an aqueous environment do not compromise the effectiveness of the coating.

Selenium functionalized intraocular lenses inhibit posterior capsule opacification in an ex vivo canine lens capsular bag assay.

The purpose of this study was to determine the inhibitory effect of selenocystamine coated intraocular lenses (IOLs) on the formation of posterior capsule opacification (PCO) in an ex vivo canine lens capsular bag assay. Selenocystamine was covalently bound to the surface of poly(2-hydroxyethyl methacrylate) (poly(HEMA)) discs. Three groups of canine lens capsules (6 coated IOLs (SeIOLs), 7 non-coated control IOLs and 8 empty capsules) were cultured for 10 days. During the culture period PCO was scored based on visual inspection of the capsules using phase contrast microscopy. On day 10 all the capsules were prepared for light microscopic examination and lens epithelial cells (LECs) were quantified. Proliferating cell nuclear antigen (PCNA), alpha-smooth muscle actin (alpha-SMA) and cleaved caspase-3 were examined by immunohistochemistry. Additionally, cell viability assays were performed on LECs cultured in tissue culture medium pre-incubated with either a SeIOL or control IOL. The viability assays demonstrated that no detectable cytotoxic leachables were associated with the functionalized IOLs. The central posterior capsule was free of cells underneath all SeIOLs, although large numbers of LECs populated the capsular periphery. Apoptotic cells were observed underneath the periphery of some SeIOLs. Both the PCO scores and LEC counts of SeIOL containing capsules were significantly lower than those of control group capsules (p < 0.01 and p = 0.0004, respectively). The use of selenium functionalized IOLs resulted in a significant reduction of PCO in this ex vivo model. Binding of selenocystamine to a foldable IOL may provide an effective method to prevent population of the central posterior capsule with LECs.