Uncoated Control Research Articles

Improving ultrasound-based brachytherapy needle conspicuity by applying an echogenic coating.

Applicator conspicuity in ultrasound-guided brachytherapy procedures is commonly impaired by imaging artifacts or non-ideal imaging geometry, which can slow down applicator position digitization and increase the geometric uncertainty of the delivered dose distribution. The purpose of this study was to improve the conspicuity of high-dose rate (HDR) brachytherapy needles under B-mode ultrasound imaging by applying an echogenic surface coating. Our hypothesis was that an echogenic coating would reduce artifacts and improve needle visualization within regions of signal degradation. In this study, 17-gauge, 25-cm long titanium HDR brachytherapy needles were coated with acoustically reflective microspheres over a 2.5cm region starting from the needle tip. Three coating thicknesses (27μm, 40μm, 64μm) were compared against an uncoated control needle. The coated and uncoated needles were imaged using B-mode ultrasound in a tissue-equivalent prostate phantom and in a cadaverous male pelvis using a transrectal probe. Needle conspicuity was assessed under multiple conditions: a single needle implant, an implant with multiple needles between the probe and the needle of interest, and an angled needle implant. All images were assessed qualitatively for needle conspicuity and the presence of artifacts and quantitatively using grey-scale image intensity values. The 64μm echogenic coating reduced the magnitude of reverberation artifacts by 31±14% and comet tail artifacts by 40%-70%. The echogenic coating also improved needle contrast, measured by the relative differences in signal intensity compared with the adjacent environment, when needles were angled up to 30° with respect to the transducer probe in the cadaver. The improvements in conspicuity and artifact reduction increased with increasing coating thickness. The performance of the needles coated with the 64μm thickness was qualitatively superior and yielded high-contrast, well-circumscribed signals in the cadaverous male pelvis, even under situations where a needle was acoustically shadowed by multiple other needles. An echogenic surface coating reduced imaging artifacts and improved needle conspicuity under realistic clinical conditions for ultrasound-based prostate or gynecological brachytherapy. The improved conspicuity has the potential to improve the efficiency of needle placement and the accuracy of needle position digitization during brachytherapy procedures.

Effect of a carrageenan/chitosan coating with allyl isothiocyanate on microbial spoilage and quality of chicken breast

Approximately 3.7% of poultry meat is lost due to spoilage each year in the United States. The objective of this study was to determine the efficacy of a layered carrageenan/chitosan coating in combination with an application of two concentrations of allyl isothiocyanate (AITC) against lactic acid bacteria, aerobic bacteria, and yeast and mold during storage of chicken breast for 21 d. Additionally, the rancidity, color, and pH of the chicken breast as indicators of non-microbial quality were evaluated. The combination of carrageenan/chitosan coating with 20 and 200 ppm AITC reduced (P ≤ 0.05) yeast and mold populations by 3 log10 CFU/g at d 21 compared to the untreated control. The carrageenan/chitosan coating with 20 and 200 ppm AITC delayed aerobic spoilage by 3 and 12 d, respectively, compared to the untreated control; aerobic bacteria populations on the samples treated with 200 ppm AITC remained below the threshold for spoilage (∼6 log10 CFU/g) for the duration of storage. The pH of the 20 ppm and 200 ppm AITC-treated chicken breast was unaltered (P > 0.05) at the end of storage and was lower than the pH of the untreated and coating-only-treated control chicken breast at d 18 through the end of storage (P ≤ 0.05). The application of the coating alone did not (P > 0.05) affect L*, a*, and b* values of the chicken breast at the end of storage compared to the uncoated control. The carrageenan/chitosan coating with 20 and 200 ppm AITC prevented decreases in the lightness (L* values) of the chicken breast at the end of storage (P ≤ 0.05) compared to the control and coating-only-treated samples. The coating alone or with AITC did not (P > 0.05) impact the rancidity of the chicken breast over the 21-d storage period, thus showing potential to be used as antimicrobial packaging to increase shelf life of fresh poultry.

Synthesis, structural characterization and in vitro pharmacological properties of betanin-encapsulated chitosan nanoparticles

Betanin, a natural food color and the only betalain, is approved for use in pharmaceutical and food industries as natural antioxidative and preservative agent, respectively. However, the antioxidant power and health-promoting properties of betanin have been disregarded due to its low stability in physiological conditions. Therefore, this study is designed to synthesize and evaluate in vitro pharmacological characteristics of betanin-encapsulated chitosan nanoparticles (ChBetNPs). ChBetNPs were synthesized by ionic gelation method and characterized by DLS, UV, FTIR, SEM and zeta potential analysis. The encapsulation efficiency (EE) and in vitro release kinetics were analyzed using spectrophotometric technique for quantifying the encapsulated amount of betanin in ChBetNPs as a function of time. The antioxidant activity of ChBetNPs was analyzed by DPPH and H2O2 radical scavenging assays, anti-inflammatory activity by protein denaturation and human RBCs stabilization assays, and anti-acetylcholinesterase activity using standard protocol with minor modifications. Unloaded chitosan nanoparticles (CSNPs) were found to be sized at 161.4 ± 5.75 nm while an increase in the size to 270.3 ± 8.50 nm was noticed upon encapsulating betanin. EE of ChBetNPs was measured to be ∼87.5%. The IC50 of ChBetNPs depicted significant free radical scavenging activities as compared to CSNPs. Similarly, a strong anti-inflammatory activity of ChBetNPs was noted. Significant decrease in acetylcholinesterase activity by ChBetNPs was measured (IC50 0.5255 μg/mL vs. control 26.09 μg/mL). The vegetables coated with 3% ChBetNPs showed decreased weight loss as compared to uncoated control. ChBetNPs was shown to exhibit strong antioxidant, anti-inflammatory and anti-acetylcholinesterase activities thus making it a significant therapeutic agent for the management of Alzheimer's disease.

Efficacy of copper blend coatings in reducing SARS-CoV-2 contamination.

SARS-CoV-2 is a highly infectious virus and etiologic agent of COVID-19, which is spread by respiratory droplets, aerosols, and contaminated surfaces. Copper is a known antiviral agent, and has resulted in successful reduction of pathogens and infections by 83-99.9% when coated on surfaces in intensive care units. Additionally, copper has been shown to inactivate pathogens such as Coronavirus 226E, a close relative of SARS-CoV-2. Here, we examine the ability of two copper blends with differing compositions to inactivate SARS-CoV-2 virus at different time points. Copper Blend 2 (75.07% pure copper) was found to significantly reduce (over 50%) the viability of SARS-CoV-2 at 5min of contact, with at least 98% reduction in recovered virus at 20min (vs. plastic control). However, Copper Blend 1 (48.26% pure copper), was not found to significantly reduce viability of SARS-CoV-2 at any time point when compared to plastic. This may indicate that there is an important percentage of copper content in materials that is needed to effectively inactivate SARS-CoV-2. Overall, this study shows that over the course of 20min, coatings made of copper materials can significantly reduce the recovery of infectious SARS-CoV-2 compared to uncoated controls, indicating the effective use of copper for viral inactivation on surfaces. Furthermore, it may suggest higher copper content has stronger antiviral properties. This could have important implications when short turnaround times are needed for cleaning and disinfecting rooms or equipment, especially in strained healthcare settings which are struggling to keep up with demand.

Cytotoxicity and anti-biofilm properties of novel hybrid-glass-based caries infiltrant.

To assess the cytotoxicity of an experimental hybrid-glass-based infiltrant and its effect on biofilm attachment, growth and metabolic activity, and to compare it to the resin-based infiltrant Icon. Cytotoxicity of hybrid-glass-based material (EXP) and resin-based infiltrant Icon (Icon) was tested in direct contact tests on freshly cured (direct_mat) and on materials kept for 24h in cell culture medium (direct_exmat), and extract test with materials 24-h extracts (extract). Cell viability of L929 mouse fibroblast cell line was measured with MTT assay, according to ISO10993-5:2009. Biofilm attachment (5h), growth (24h and 48h) and lactic-acid production (24h and 48h) on glass-disk specimens coated with EXP or Icon, or uncoated (control), were assessed using a microcosm biofilm model and Amsterdam Active Attachment system. At indicated time points, biofilms were harvested, plated, and CFU counts were determined, while lactic-acid production was measured colorimetrically. Cell viability reduction by EXP was below 30%-threshold in direct contact tests, while in extract test an increased cell viability was observed. Icon reduced cell viability substantially in all three tests. Significantly less bacteria attached to the surface of EXP after 5h compared to Icon and control. Biofilm growth was significantly lower on EXP than on Icon and control after 24h, but this difference was smaller and statistically insignificant after 48h. There was no difference in lactic-acid production among groups. Novel hybrid-glass-based infiltrant seems to have a better biocompatibility and accumulates on its surface less bacteria than resin-based infiltrant, which makes it an attractive resin-free alternative.

Development and Application of Dual-Sensors Label in Combination with Active Chitosan-Based Coating Incorporating Yarrow Essential Oil for Freshness Monitoring and Shelf-Life Extension of Chicken Fillet.

This study aimed for the application of active chitosan coating incorporating yarrow essential oil (YEO) together with the development of an on-package sensor label based on bromocresol purple (BCP) and methyl red (MR) for shelf-life extension and freshness monitoring of chicken breast fillet. Physiochemical and microbiological attributes of chicken meat coated with sole chitosan, YEO, and chitosan + YEO were compared with those of uncoated (control) samples. Chitosan + YEO coated chicken meat stayed fresh with no significant changes (p > 0.05) in pH (5.42-5.56), TVB-N (12.55-15.36 mg N/100 g), TBARs (0.35-0.40 mg MDA/kg) and total aerobic psycrotrophic bacteria (3.97-4.65 log CFU/g) in days 1-15. There was no response of the dual-sensors label toward the variation in chemical and microbiological indicators of chicken meat coated with chitosan + YEO. However, either uncoated, sole chitosan, or sole YEO treatments indicated a three-stage freshness status with the fresh stage belonged to a period earlier than day 7 (with no distinct color change in both sensor labels); the semi-fresh stage corresponded to storage days between 7-9, wherein a gradual color change appeared (MR from pink to orange, BCP from yellow to light purple); and the spoiled stage occurred in day 9 onward with a drastic color change (MR from orange to light yellow, BCP from light purple to deep purple). In general, the dual-sensors successfully responded to the variation of chemical and microbiological indicators and visual color of uncoated samples during storage time. Based on the obtained results, the application of chitosan + YEO coating efficiently prolonged the freshness of chicken breast meat, where on-package dual-sensors systems were able to detect the freshness stages of meat samples during storage time.

Improved Recovery of Captured Airborne Bacteria and Viruses with Liquid-Coated Air Filters.

The COVID-19 pandemic has revealed the importance of the detection of airborne pathogens. Here, we present composite air filters featuring a bioinspired liquid coating that facilitates the removal of captured aerosolized bacteria and viruses for further analysis. We tested three types of air filters: commercial polytetrafluoroethylene (PTFE), which is well known for creating stable liquid coatings, commercial high-efficiency particulate air (HEPA) filters, which are widely used, and in-house-manufactured cellulose nanofiber mats (CNFMs), which are made from sustainable materials. All filters were coated with omniphobic fluorinated liquid to maximize the release of pathogens. We found that coating both the PTFE and HEPA filters with liquid improved the rate at which Escherichia coli was recovered using a physical removal process compared to uncoated controls. Notably, the coated HEPA filters also increased the total number of recovered cells by 57%. Coating the CNFM filters did not improve either the rate of release or the total number of captured cells. The most promising materials, the liquid-coated HEPA, filters were then evaluated for their ability to facilitate the removal of pathogenic viruses via a chemical removal process. Recovery of infectious JC polyomavirus, a nonenveloped virus that attacks the central nervous system, was increased by 92% over uncoated controls; however, there was no significant difference in the total amount of genomic material recovered compared to that of controls. In contrast, significantly more genomic material was recovered for SARS-CoV-2, the airborne, enveloped virus, which causes COVID-19, from liquid-coated filters. Although the amount of infectious SARS-CoV-2 recovered was 58% higher, these results were not significantly different from uncoated filters due to high variability. These results suggest that the efficient recovery of airborne pathogens from liquid-coated filters could improve air sampling efforts, enhancing biosurveillance and global pathogen early warning.

Alginate and Aloe vera gel-based edible coating for the storage stability enhancement of fresh-cut MD2 pineapple

Fresh-cut fruits are susceptible to deterioration due to tissue wounding during the preparation process which caused a shorter shelf-life of fresh-cut fruits. This study aimed to compare the storage stability of fresh-cut MD2 pineapples coated with alginate versus fresh-cut MD2 pineapples with Aloe vera gel-based coating. The physicochemical properties, microbiological changes, and quality changes of coated fresh-cut MD2 pineapples were analysed during low-temperature storage (5±1°C) under 85±10% of relative humidity for 16 days. Uncoated pineapples were used as the control and stored under the same storage conditions as the treated pineapples. The Aloe vera-coated pineapples showed a significantly (p < 0.05) lower amount of fluid loss, total plate count, as well as yeast and mould counts, as compared to the uncoated controls. The alginatecoated pineapples were brighter and more yellowish during storage compared to the control, therefore slightly extending the fruit shelf life. Overall, the Aloe vera gel-based edible coating was more effective at retaining the storage stability of fresh-cut MD2 pineapple, as it maintained its microbiological quality for up to 14 days and reduced fluid loss.

Modification of Shellac with Clove (Eugenia caryophyllata) and Thyme (Satureja hortensis) Essential Oils: Compatibility Issues and Effect on the UV Light Resistance of Wood Coated Surfaces

Shellac (SL) is a natural resin employed for wood finishing, while clove (Eugenia caryophyllata) and thyme (Satureja hortensis) essential oils (C-EO, T-EO) are organic natural products of vegetal origin with antifungal, antimicrobial and antioxidant properties. The present paper aims at exploring the potential of modifying alcoholic shellac solutions with essential oils (C-EO, T-EO), focussing on the recurrent effects of this modification on the traditional wood finishing technique, the colour and the UV light resistance of the wood coated surfaces. The compatibility of C-EO and T-EO with ethyl alcohol and the alcoholic reference SL solution was evaluated, and modified SL solutions with a content of 5% and 10% C-EO and T-EO were prepared. Wood samples of European maple (Acer pseudoplatanus) and European walnut (Juglans regia) were finished with reference and modified SL solutions. An accelerated UV ageing test was run, and the samples were evaluated after 24, 48 and 72 h of exposure. Colour measurements in the CIELab system and FTIR–ATR investigation were employed for monitoring colour and surface chemistry changes. Coating with SL resulted in visible colour changes for both wood species (ΔE values of 31.06 for maple and 13.00 for walnut) and increased UV resistance, reducing colour changes after 72 h UV exposure (by 83% for maple and by 59% for walnut) as compared to the uncoated controls. Modification of SL solutions with C-EO and T-EO only slightly influenced the colour of finished surfaces (ΔE = 1.88–5.41 for maple, ΔE = 1.36–3.41 for walnut) and their UV resistance. The colour changes (ΔE) of coated surfaces after 72 h exposure varied in the range 1.63–4.53 for maple and 2.39–3.58 for walnut, being generally slightly higher (by 1.7–2.9 units for maple and 0–1 unit for walnut) for the modified SL solutions. FTIR investigation highlighted only minor chemical changes of the shellac coating films after 72 h of UV exposure. A photo-induced oxidative process of eugenol seemed possible in the case of SL modified with C-EO.

Tethering zwitterionic polymer coatings to mediated glucose biosensor enzyme electrodes can decrease sensor foreign body response yet retain sensor sensitivity to glucose

Foreign body response (FBR) is a major challenge that affects implantable biosensors and medical devices, including glucose biosensors, leading to a deterioration in device response over time. Polymer shields are often used to mitigate this issue. Zwitterionic polymers (ZPs) are a promising class of materials that reduce biofouling of implanted devices. A series of ZPs each containing tetherable epoxide functional groups was synthesised for application as a polymer shield for eventual application as implantable glucose biosensors. The polymer shields were initially tested for the ability to resist fibrinogen adsorption and fibroblast adhesion. All synthesised ZPs showed comparable behaviour to a commercial Lipidure ZP in resisting fibrinogen adsorption. Nafion, a common anionic shield used against electrochemical interferents, showed higher protein adsorption and comparable cell adhesion resistance as uncoated control surfaces. However, a poly(2-methacryloyloxyethyl phosphorylcholine-co-glycidyl methacrylate) (MPC)-type ZP showed similar behaviour to Lipidure, with approximately 50% reduced fibrinogen adsorption and 80% decrease in fibroblast adhesion compared to uncoated controls. An MPC-coated amperometric glucose biosensor showed comparable current density and a 1.5-fold increase in sensitivity over an uncoated control biosensor, whereas all other polymer shields tested, including Lipidure, Nafion and a poly(ethyleneglycol) polymer, resulted in lower sensitivity and current density. Collectively, these characteristics make MPC-polymer shield coatings an appealing possibility for use in implantable glucose sensors and other implanted devices with the aim of reducing FBR while maintaining sensor performance.

Zwitterionic Polymer/Polydopamine Coating of Electrode Arrays Reduces Fibrosis and Residual Hearing Loss after Cochlear Implantation.

Since the first surgery 50 years ago, cochlear implantation (CI) is the major treatment for patients with severe sensorineural hearing loss. However, unexpected foreign body reactions (FBRs) after surgery are reported in 90% of CI recipients, resulting in the formation of fibrosis in the cochlea and progressive residual hearing loss. Zwitterion modification is universally used to reduce bio-fouling and suppress FBRs but never for CI. In the present study, a zwitterionic coating is developed, which is composed of poly sulfobetaine methacrylate (PSB) and polydopamine (PDA) for cochlear implants. The PSB-PDA coating shows a series of characters for an ideal anti-FBRs material, including super-hydrophilicity, low protein and cell adsorption, long-term stability, and high biocompatibility. Compared to the uncoated controls, PSB-PDA coating inhibits the activation of macrophages and reduces the release of inflammatory factors (TNF-α, IL-1β, NO) and fibrosis-related factors (TGF-β1, α-SMA, collagen I). PSB-PDA coated electrode arrays suppress fibrosis completely and preserve residual hearing significantly in rat CI models. These results suggest that PSB-PDA coating is a novel strategy for anti-fibrosis to improve the outcomes of CI.

Mechanical Stability of Nano-Coatings on Clinically Applicable Electrodes, Generated by Electrophoretic Deposition.

The mechanical stability of implant coatings is crucial for medical approval and transfer to clinical applications. Here, electrophoretic deposition (EPD) is a versatile coating technique, previously shown to cause significant post-surgery impedance reduction of brain stimulation platinum electrodes. However, the mechanical stability of the resulting coating has been rarely systematically investigated. In this work, pulsed-DC EPD of laser-generated platinum nanoparticles (PtNPs) on Pt-based, 3D neural electrodes is performed and the in vitro mechanical stability is examined using agarose gel, adhesive tape, and ultrasonication-based stress tests. EPD-generated coatings are highly stable inside simulated brain environments represented by agarose gel tests as well as after in vivo stimulation experiments. Electrochemical stability of the NP-modified surfaces is tested via cyclic voltammetry and that multiple scans may improve coating stability could be verified, indicated by higher signal stability following highly invasive adhesive tape stress tests. The brain sections post neural stimulation in rats are analyzed via laser ablation-inductively coupled plasma-mass spectrometry (LA-ICP-MS). Measurements reveal higher levels of Pt near the region stimulated with coated electrodes, in comparison to uncoated controls. Even though local concentrations in the vicinity of the implanted electrode are elevated, the total Pt mass found is below systemic toxicologically relevant concentrations.

Physicochemical, Morphological, and Functional Characterization of Edible Anthocyanin-Enriched Aloevera Coatings on Fresh Figs (Ficus carica L.).

In the present investigation, Aloe vera gel (AVG)-based edible coatings enriched with anthocyanin were prepared. We investigated the effect of different formulations of aloe-vera-based edible coatings, such as neat AVG (T1), AVG with glycerol (T2), Aloe vera with 0.2% anthocyanin + glycerol (T3), and AVG with 0.5% anthocyanin + glycerol (T4), on the postharvest quality of fig (Ficus carica L.) fruits under refrigerated conditions (4 °C) for up to 12 days of storage with 2-day examination intervals. The results of the present study revealed that the T4 treatment was the most effective for reducing the weight loss in fig fruits throughout the storage period (~4%), followed by T3, T2, and T1. The minimum weight loss after 12 days of storage (3.76%) was recorded for the T4 treatment, followed by T3 (4.34%), which was significantly higher than that of uncoated fruit (~11%). The best quality attributes, such as the total soluble solids (TSS), titratable acidity (TA), and pH, were also demonstrated by the T3 and T4 treatments. The T4 coating caused a marginal change of 0.16 in the fruit titratable acidity, compared to the change of 0.33 in the untreated fruit control after 12 days of storage at 4 °C. Similarly, the total soluble solids in the T4-coated fruits increased marginally (0.43 °Brix) compared to the uncoated control fruits (>2 °Brix) after 12 days of storage at 4 °C. The results revealed that the incorporation of anthocyanin content into AVG is a promising technology for the development of active edible coatings to extend the shelf life of fig fruits.

Antifouling coatings can reduce algal growth while preserving coral settlement

In the early stages after larval settlement, coral spat can be rapidly overgrown and outcompeted by algae, reducing overall survival for coral reef replenishment and supply for restoration programs. Here we investigated three antifouling (AF) coatings for their ability to inhibit algal fouling on coral settlement plugs, a commonly-used restoration substrate. Plugs were either fully or partially coated with the AF coatings and incubated in mesocosm systems with partial recirculation for 37 days to track fouling succession. In addition, settlement of Acropora tenuis larvae was measured to determine whether AF coatings were a settlement deterrent. Uncoated control plugs became heavily fouled, yielding only 4–8% bare substrate on upper surfaces after 37 days. During this period, an encapsulated dichlorooctylisothiazolinone (DCOIT)-coating was most effective in reducing fouling, yielding 61–63% bare substrate. Antiadhesive and cerium dioxide (CeO2−x) nanoparticle (NP) coatings were less effective, yielding 11–17% and 2% bare substrate, respectively. Average settlement of A. tenuis larvae on the three types of AF-coated plugs did not statistically differ from settlement on uncoated controls. However, settlement on the NP-coating was generally the highest and was significantly higher than settlement found on the antiadhesive- and DCOIT-coating. Furthermore, on plugs only partially-covered with AF coatings, larval settlement on coated NP- areas was significantly higher than settlement on coated antiadhesive- and DCOIT-areas. These results demonstrate that AF coatings can reduce fouling intensity on biologically-relevant timescales while preserving robust levels of coral settlement. This represents an important step towards reducing fine-scale competition with benthic fouling organisms in coral breeding and propagation.

Effect of Cissus quadrangularis Hydrogel on Enhancing Osseointegration of Titanium Implant to Bone: An In Vivo Study

The aim of the study was to evaluate the osteogenic potential of Cissus quadrangularis (CQ) hydrogel in enhancing the osseointegration of titanium to the bone in an experimental rabbit model. Six adult male New Zealand white rabbits were used in this study. A total of 24 implants (12 coated test implants and 12 uncoated control implants) were placed in these 6 rabbits. A polyethylene glycol (PEG) hydrogel was prepared with the C. quadrangularis hydrogel in which the test implants were coated. Each rabbit was operated on both hind legs and one implant, each, was placed in the femur and tibia. Hence, one rabbit received four implants [two test implants (HG coated) and two control implants (uncoated)]. The animals were sacrificed after 4 weeks, and the specimens were histomorphometrically analyzed. The bone-to-implant contact (BIC) and the bone area fraction occupancy (BAFO) were calculated using Image J analysis. The statistically analyzed values which were obtained by paired t-test, revealed that the average mean values were higher in the test implants (coated) than the control implants (uncoated). The BIC values of the test implants were not significantly different from the control implants in the case of both femur and tibia (p >0.05). The test implants showed significantly increased BAFO values in femur (p <0.05). However, the BAFO values of test implants in tibia did not vary significantly from the control implants. Based on the findings of the study, the authors conclude that the coating of C. quadrangularis hydrogel enhances the osseointegration of titanium implants to bone. The further studies need to be designed to check the osseointegrative potential of C. quadrangularis. The findings of this study suggest that the C. quadrangularis hydrogel is a potent osteogenic material that can reduce the osseointegration period and thus enhance the patient compliance toward implant treatment.

Antimicrobial and Antioxidant Effects of Kappa-Carrageenan Coatings Enriched with Cinnamon Essential Oil in Pork Meat.

Fresh pork is susceptible to microbial contamination and lipid oxidation, which leads to food safety and quality issues. This study aimed to develop a kappa-carrageenan (KC) coating embedded with cinnamon essential oil (CEO) for antimicrobial and antioxidant purposes in pork meat. The uncoated controls and coated samples were subjected to microbial (total viable count, lactic acid bacteria, and H2S-producing bacteria), chemical (DPPH and pH), and physical (surface color) analyses during refrigerated storage at 4 °C for 7 days. It was observed that KC coatings exhibited a better preservation effect on pork meat after the addition of CEO. The KC–CEO coatings were effective in retarding the growth of total viable count, lactic acid bacteria, and H2S-producing bacteria. In a DPPH test, the level of lipid oxidation in pork meat was also significantly (p < 0.05) reduced by the KC–CEO coatings. Furthermore, these coatings displayed pronounced activity in inhibiting the adverse alterations of pH value and surface color. Practically, KC–CEO-coated samples still exhibited an attractive bright red color at the end of refrigerated storage. Taken together, the developed KC–CEO coatings exerted pronounced antimicrobial and antioxidant activities in pork, thus providing a potential approach to preserving perishable meat.

Biofilm-responsive encapsulated-phage coating for autonomous biofouling mitigation in water storage systems

Biofilms in water storage systems may harbor pathogens that threaten public health. Chemical disinfectants are marginally effective in eradicating biofilms due to limited penetration, and often generate harmful disinfection byproducts. To enhance biofouling mitigation in household water storage tanks, we encapsulated bacteriophages (phages) in chitosan crosslinked with tri-polyphosphate and 3-glycidoxypropyltrimethoxysilane. Phages served as self-propagating green biocides that exclusively infect bacteria. This pH-responsive encapsulation (244 ± 11 nm) enabled autonomous release of phages in response to acidic pH associated with biofilms (corroborated by confocal microscopy with pH-indicator dye SNARF-4F), but otherwise remained stable in pH-neutral tap water for one month. Encapsulated phages instantly bind to plasma-treated plastic and fiberglass surfaces, providing a facile coating method that protects surfaces highly vulnerable to biofouling. Biofilm formation assays were conducted in tap water amended with 200 mg/L glucose to accelerate growth and attachment of Pseudomonas aeruginosa, an opportunistic pathogen commonly associated with biofilms in drinking water distribution and storage systems. Biofilms formation on plastic surfaces coated with encapsulated phages decreased to only 6.7 ± 0.2% (on a biomass basis) relative to the uncoated controls. Likewise, biofilm surface area coverage (4.8 ± 0.2 log CFU/mm2) and live/dead fluorescence ratio (1.80) were also lower than the controls (6.6 ± 0.2 log CFU/mm2 and live/dead ratio of 11.05). Overall, this study offers proof-of-concept of a chemical-free, easily implementable approach to control problematic biofilm-dwelling bacteria and highlights benefits of this bottom-up biofouling control approach that obviates the challenge of poor biofilm penetration by biocides.

Synthesis of α-Fe2O3/ethyl cellulose-based nanocomposites to extend the shelf-life of Capsicum annuum L. var. grossum

Nanobiotechnology has great potential to improve the shelf-life of eatables with essential nutrient quality. Synthesized nanocomposites were applied to prolong the shelf life of Bell Pepper (Capsicum annuum L. var. grossum). α-Fe2O3 nanoparticles were synthesized using the hydrothermal method and characterized with FTIR and XRD techniques. XRD confirms the crystalline nature of α-Fe2O3 nanoparticles. α-Fe2O3 nanoparticles exhibit remarkable anti-pathogenic properties against Staphylococcus aureus. α-Fe2O3/ethyl cellulose nanocomposite dip-coated bell pepper samples with three different concentrations; FA (1 mg/ml), FB (0.75 mg/ml), FC (0.5 mg/ml) and FU (uncoated control) were studied up to 14 days at room temperature (27 ± 2 °C). Results suggested that nanocomposites enhanced the shelf life of the coated Bell Pepper by preventing microbial and fungal proliferation.Moreover, the nanocomposites did not affect any quality aspects of the Bell Pepper, such as pH, chlorophyll content, moisture content, ascorbic acid, and weight loss. This present study demonstrates that synthesized nanocomposite antimicrobial films can maintain the quality of vegetables and retards microbial and fungal growth in Bell Pepper.

A Biocompatibility Study of Plasma Nanocoatings onto Cobalt Chromium L605 Alloy for Cardiovascular Stent Applications.

The objective of this study was to evaluate the biocompatibility of trimethylsilane (TMS) plasma nanocoatings modified with NH3/O2 (2:1 molar ratio) plasma post-treatment onto cobalt chromium (CoCr) L605 alloy coupons and stents for cardiovascular stent applications. Biocompatibility of plasma nanocoatings was evaluated by coating adhesion, corrosion behavior, ion releasing, cytotoxicity, and cell proliferation. Surface chemistry and wettability were studied to understand effects of surface properties on biocompatibility. Results show that NH3/O2 post-treated TMS plasma nanocoatings are hydrophilic with water contact angle of 48.5° and have a typical surface composition of O (39.39 at.%), Si (31.92 at.%), C (24.12 at.%), and N (2.77 at.%). The plasma nanocoatings were conformal to substrate surface topography and had excellent adhesion to the alloy substrates, as assessed by tape test (ASTM D3359), and showed no cracking or peeling off L605 stent surfaces after dilation. The plasma nanocoatings also improve the corrosion resistance of CoCr L605 alloy by increasing corrosion potential and decreasing corrosion rates with no pitting corrosion and no mineral adsorption layer. Ion releasing test revealed that Co, Cr, and Ni ion concentrations were reduced by 64–79%, 67–69%, and 57–72%, respectively, in the plasma-nanocoated L605 samples as compared to uncoated L605 control samples. The plasma nanocoatings showed no sign of cytotoxicity from the test results according to ISO 10993-05 and 10993-12. Seven-day cell culture demonstrated that, in comparison with the uncoated L605 control surfaces, the plasma nanocoating surfaces showed 62 ± 7.3% decrease in porcine coronary artery smooth muscle cells (PCASMCs) density and had comparable density of porcine coronary artery endothelial cells (PCAECs). These results suggest that TMS plasma nanocoatings with NH3/O2 plasma post-treatment possess the desired biocompatibility for stent applications and support the hypothesis that nanocoated stents could be very effective for in-stent restenosis prevention.

A Vascular Graft On‐a‐Chip Platform for Assessing the Thrombogenicity of Vascular Prosthesis and Coatings with Tuneable Flow and Surface Conditions

AbstractVascular grafts are essential for the management of cardiovascular disease. However, the lifesaving potential of these devices is undermined by thrombosis arising from material and flow interactions on the blood contacting surface. To combat this issue, antithrombogenic coatings have emerged as a promising strategy for modulating blood and graft interaction in vivo. Although an important determinant of graft performance, hemodynamics are frequently overlooked for in vitro testing of coatings and their translatability remains poorly understood. Herein, this limitation is addressed with a microscale graft on‐a‐chip platform incorporating vascular prosthesis and coatings with tuneable flow and surface conditions in vitro. As a proof of concept, the platform is used to test the thrombogenicity of a novel class of lubricant‐infused surface (LIS) and antibody lubricant‐infused (anti‐CD34 LIS) coated expanded polytetrafluoroethylene (ePTFE) vascular grafts in the presence of arterial wall shear stress with and without endothelial cells. The findings suggest LIS ePTFE is thromboresistant under flow with significantly reduced fibrin(ogen) deposition, thrombin activity, and blood cell adhesion compared to uncoated controls. It is moreover apparent that the microscale properties of the device are advantageous for the testing and translation of novel antithrombogenic coatings and blood‐contacting materials in general.