Effective Decontamination Research Articles

Effective decontamination of DR-81 dye from aqueous solutions using eco-friendly graphene oxide nanoparticles.

Effective management of industrial and agricultural wastes requires a multifaceted approach that considers environmental, economic, and social factors. Our ability to recover resources and create a circular bioeconomy from agricultural waste can be enhanced by implementing sustainable methods such as reducing, reusing, and recycling it. Active graphene oxide (GO) was prepared through the gasification of agricultural waste and further mixed with FeAlOx catalyst for three hours at 800°C as an efficient adsorbent. The synthesized material was comprehensively characterized using Fourier-transform infrared spectroscopy, X-ray diffraction, high-resolution transmission electron microscopy, X-ray photoelectron spectroscopy, Brunauer-Emmett-Teller surface area analysis, and thermal gravimetrical analysis. In order to remove direct red 81 (DR-81) dye from wastewater, the synthesized nanomaterial was implemented as an effective adsorbent. Several processing variables, including pH, contact time, and dosage, were studied to examine the optimum conditions that directly influence the DR-81 decontamination of onto the fabricated GO. The optimal dosage from the synthesized GO for DR-81 decontamination was 0.5g/L at pH = 7 after 30min. At pH 7.0 and 25°C, the produced GO had the highest sorption capacity of 132.14mg/g towards the DR-81. In addition, equilibrium and kinetic studies were capably fitted via the Freundlich and pseudo-second-order models, respectively. As a result of its particular properties, which include a high surface area, adsorption capacity, structural robustness, variation tolerance, and thermal stability. These promising findings supported the usage of synthesized GO as a superior adsorbent material for DR-81 decontamination from wastewater.

Bio-based sulfonated surfactants with high Ca2+ tolerance in detergent formulations

The use of calcium-resistant surfactants in household and industrial washing applications may simplify the formulation composition of laundry and therefore reduce costs. A series of bio-based surfactants, N-alkyl furfuryl methylamine sulfonates (AFMS), was developed from the biomass-derived furfural and aliphatic amines by a simple and effective method. The structure of these bio-based surfactants was characterized by gas chromatography–mass spectrometry, liquid chromatography–mass spectrometry and 1H nuclear magnetic resonance spectroscopy. These bio-based surfactants demonstrated low surface tension, high emulsification, and high decontamination efficiency. Meanwhile, the AFMS surfactants exhibited excellent calcium resistance, maintaining micelle stability in Ca2+up to 2.16 × 104 mg/L and the solution clarification in Ca2+up to 7.21 × 104 mg/L. Furthermore, the AFMS surfactants had a stable decontamination effect in hard water. The wetting ability, foaming ability, toxicity, and biodegradability parameters were also evaluated. Therefore, the AFMS surfactants synthesized in this work could be applied as a more efficient and promising bio-based surfactant candidate for application in household and industrial washing.

Decolonization strategies for ESBL-producing or carbapenem-resistant Enterobacterales carriage: a systematic review and meta-analysis

The prevalence of extended-spectrum β-lactamase-producing Enterobacterales (ESBL-E) and carbapenem-resistant Enterobacterales (CRE) has become a global public health problem. ESBL-E/CRE colonization can increase the risk of infection in patients and lead to poor disease prognosis. We conducted a systematic review and meta-analysis to evaluate current decolonization strategies regarding ESBL-E/CRE and their efficacy. A literature search was conducted until August 2023 on the five databases to review decolonization strategies associated with ESBL-E/CRE. A meta-analysis was conducted using RevMan 5.4 to compare differences in the decolonization strategy with placebo controls. The primary outcome was decolonization rates, with secondary outcomes of attributable death and adverse events. Quality of identified studies was determined using the Newcastle–Ottawa scale and cochrane risk assessment tool. Random and fixed effects meta-analyses were performed to calculate pooled value. A total of 25 studies were included. In five randomized controlled trial (RCT) studies, the decolonization effect of selective digestive decontamination(SDD) on ESBL-E/CRE at the end of treatment was significantly better in the experimental group than the controls [risk radio (RR): 3.30; 95% CI 1.78–6.14]. In three n-RCT studies, the decolonization effect in the experimental group was still better than the controls one month after SDD therapy [odds ratio (OR): 4.01; 95% CI 1.88–8.56]. The combined decolonization rates reported by six single-arm trial studies of SDD therapy ranged from 53.8 to 68.0%. Additionally, TSA analysis confirmed the effectiveness of SDD therapy. In studies on Faecal microbiota transplantation (FMT) therapy, the decolonization effect of the experimental group was significantly better than the controls 1 month after treatment (OR: 2.57; 95% CI 1.07–6.16). In studies without a control group and with varying follow-up times, the decolonization rates varied widely but indicated the effectiveness trend of FMT therapy (61.3–81.2%). Currently, research on the decolonization effect of probiotic therapy on ESBL-E/CRE is insufficient, and only a systematic review was conducted. SDD and FMT strategies have short-term benefits for ESBL-E/CRE decolonization, but long-term effects are unclear. The effect of probiotic therapy on ESBL-E/CRE decolonization is an interesting topic that still requires further investigation.

How to alleviate seasonal limitations on water quality in farmland ditches? The importance of plant selection and configuration

In subtropical monsoon climate regions, traditional plants in constructed wetlands such as farmland ditches underperform in cold months, detracting from both purification capacity and esthetic appeal. To alleviate this weakness, this study introduced Phalaris arundinacea, a species with strong adaptability and cold tolerance, into a plant community dominated by Phragmites australis, constructing an ingenious composite plant community for year‐round water quality restoration and enhancement of attractiveness. First, laboratory simulations revealed significant seasonal differences in the removal rates of ammonia nitrogen (NH3‐N), total nitrogen (TN), and total phosphorus (TP) by the P. arundinacea community and P. australis community under different pollutant loads. Phragmites australis showed superior NH3‐N and TN removal capabilities from May to October, whereas P. arundinacea excelled in the rest of the months throughout the year. For TP removal, P. australis outperformed P. arundinacea from July to October, while P. arundinacea was more effective from January to May. We then verified this in rear farmland ditches, where P. australis were strategically partial substituted with P. arundinacea (Partial Replacement Treatment [PRT]), and compared it with unchanged farmland ditches (Control Treatment). We found that PRT enhanced decontamination efficiency over the year, especially significantly improving the water quality during colder months. Hence, this study advocates a novel strategy for effective annual decontamination and maintenance of wetlands such as farmland ditches, highlighting the importance of seasonally adaptive plant communities for water restoration. This transformative approach dramatically advances the field of wetland management, insisting on the important role of cold‐resistant species for year‐round ecosystem service optimization.

Synthesis and evaluation of radioactive decontamination efficiency of carboxylic 4-tert-butylcalix[6]arene derivative with decontamination solution

ABSTRACT Scientists have recently conducted thorough investigations on tert-butylcalix[6]arene and its derivatives owing to their ability to form complexes with radioactive elements for applications in radioactive decontamination. Current research presents the result of synthesising compounds 1,3,5-trimethoxy-2,4,6-tri (carboxylic acid)-4-tert-butylcalix[6]arene and evaluates the influence of this compound on the decontamination efficiency of a new skin decontamination (SD) kit developed by Lequidon laboratory. Decontamination effectiveness for short-lived radionuclides: metal (134Cs) and non-metallic (131I) determined by in vivo method. Adding 1% of 4-tert-butyl calix[6]arene derivative significantly enhanced the efficiency of the radioactive decontamination solution (SD).

Efficacité de 6 scénarios de décontamination de bras de fauteuils contaminés volontairement au cyclophosphamide

The arms of chairs in outpatient oncology clinics are frequently contaminated with cyclophosphamide. To evaluate the effectiveness of decontamination scenarios. This was a descriptive simulation-type study of 6 decontamination scenarios of a silicone fabric surface contaminated with 10 μg of cyclophosphamide. The decontamination products tested (quaternary ammonium, 0.5% hydrogen peroxide, 0.005% detergent, and sodium hypochlorite 0.5%) were applied with microfibre wipes. Residual contamination was measured using an ultra-performance liquid chromatography-tandem mass spectrometry system with identical cyclophosphamide detection and quantification limits (0.0006 ng/cm2). Among the 59 samples, 3 blanks were negative, 5 allowed measurement of the recovery rate (93.7% [standard deviation 4.6%]), and 51 were experimental. The average efficiency of the agents was greater than or equal to 99.79%. Regardless of the agent used, effectiveness was 99.30% (SD 1.20%) after 1 cleanse (n = 18), 99.90% (SD 0.15%) after 2 cleanses (n = 18), and 99.95% (SD 0.06%) after 3 cleanses (n = 15). The 6 decontamination scenarios were effective. Repeated cleaning marginally increased the effectiveness of decontamination.

Plasma-Functionalized Liquids for Decontamination of Viable Tissues: A Comparative Approach

Plasma-functionalized liquids (PFLs) are rich in chemical species, such as ozone, hydrogen peroxide, singlet oxygen, hydroxyl radical and nitrogen oxides, commonly referred to as reactive oxygen and nitrogen species (RONS). Therefore, manifold applications are being investigated for their use in medicine, agriculture, and the environment. Depending on the goal, a suitable plasma source concept for the generation of PFLs has to be determined because the plasma generation setup determines the composition of reactive species. This study investigates three PFL-generating plasma sources—two spark discharges and a flow dielectric barrier discharge (DBD) system—for their efficacy in eliminating microbial contaminants from tissue samples aiming to replace antibiotics in the rinsing process. The final goal is to use these tissues as a cell source for cell-based meat production in bioreactors and thereby completely avoid antibiotics. Initially, a physicochemical characterization was conducted to better understand the decontamination capabilities of PFLs and their potential impact on tissue viability. The results indicate that the flow DBD system demonstrated the highest antimicrobial efficacy due to its elevated reactive species output and the possibility of direct treatment of tissues while tissue integrity remained. Achieving a balance between effective large-scale decontamination and the biocompatibility of PFLs remains a critical challenge.

Comparison of Decontamination-Preservation Protocols for Delayed Surgical Re-implantation of Osteoarticular Fracture Fragments

Background: To avoid discarding contaminated, devascularized osteoarticular fragments required for joint reconstruction, fragments need to be decontaminated while preserving chondrocyte viability. We hypothesized that disinfection with povidone-iodine or chlorhexidine followed by preservation using the Missouri Osteochondral Preservation System (MOPS) would allow for effective decontamination while retaining essential chondrocyte viability in osteoarticular fracture fragments for up to 14 days of shelf-stable point-of-care storage. Methods: With IACUC approval, purpose-bred hounds (n=16) were humanely euthanized for unrelated purposes and subjected to captive bolt trauma to create open distal humeral fractures. For each elbow (n=32), humerus, radius and ulna tissues were recovered such that 96 contaminated, devascularized osteoarticular fragments were randomly allocated to one treatment: Betadine (n=42): saline irrigation (1L), immersion in 10% povidone-iodine (20 min), saline irrigation; Chlorhexidine (n=42): saline irrigation, immersion in 0.002% chlorhexidine gluconate (20 min), saline irrigation; Injured Control (n=12): no decontamination treatment. After 7 or 14 days in MOPS, tissues were assessed by quantitative microbial culture and Viable Chondrocyte Density (VCD) measures. Results: Captive bolt trauma consistently resulted in type 3 open articular fractures. Injured Control osteoarticular fragments produced high polymicrobial counts at days 7 and 14. Chlorhexidine treatment was effective for decontaminating fragments such that no CFUs for clinically relevant bacteria were produced, while Betadine treatment was not fully effective at decontamination. Chlorhexidine decontamination followed by MOPS preservation maintained VCD in osteoarticular tissues over the desired 70% mean for 14 days, whereas the Injured Control group was associated with significant loss of VCD (Day-7=59%, Day-14=13%), which was further exacerbated by Betadine treatment (Day-7=29%, Day-14=6%). Conclusion: Contaminated, devascularized osteoarticular fracture fragments can be effectively decontaminated while maintaining essential chondrocyte viability for 14 days after type 3 open articular fractures using a decontamination-preservation protocol that combines saline irrigation with 0.002% chlorhexidine immersion followed by shelf-stable point-of-care storage in MOPS.

Removal of Surface Radioactive Uranium(Ⅵ) by Graphene Oxide Modified κ-carrageenan/Konjac Glucomannan Composite Hydrogel

Hydrogel is an effective surface decontamination technology. However, traditional colloid decontaminants face a long curing time and low decontamination rate. A peelable hydrogel coating composed of carrageenan, konjac glucan, and graphene oxide with excellent film-forming performance and decontamination efficiency was explored in this study. The results showed that the graphene oxide was effectively dispersed inside the hydrogel, improving the crosslink density and thermal stability of the hydrogel by forming hydrogen bonds with polysaccharide molecules. The graphene oxide can effectively enhance the decontamination performance of the hydrogel. For stainless steel, ceramic, glass, and rubber surfaces, the decontamination rates of the hydrogel for 30min were 96.95%, 87.6%, 96.27%, and 74.5%, respectively. The decontamination effect was stable to temperature. For cement surfaces, the hydrogel could reach a maximum decontamination rate of 70.68% after 24h. The decontamination efficiency of hydrogel was affected by porosity, surface roughness, and graphene oxide addition. The characterization results of XPS, FT-IR, and SEM/EDS showed that the decontamination process of the composite hydrogel may involve surface wetting, ion diffusion, electrostatic attraction, and physical entanglement.

Investigating cold plasma jet effectiveness for eggshell surface decontamination

Ensuring the safety of eggs, a valuable source of high-quality protein and essential vitamins, is critical to prevent foodborne illness. Cold plasma, an emerging green technology, generates various reactive species that effectively inactivate microorganisms, attracting global attention for its potential in food safety. This study aims to explore the application of cold plasma as a chemical-free, non-thermal approach for decontaminating egg surfaces and to assess its potential as an alternative to conventional egg-washing methods. Various operation conditions of a cold plasma jet device, including power levels (300–400 W), exposure times (20–60 s), distances between the nozzle and eggshell (1–3 cm), airflow rates (30–35 L/min), and feed gases (nitrogen, air (20 %–65 % relative humidity), helium and air mixtures), were examined to decontaminate hen eggshells inoculated with Escherichia coli and Salmonella enterica bacteria. The results showed a maximum log reduction and deactivation efficiency of 1.94 and 98.74 % for E. coli, and 1.11 and 92.20 % for Salmonella, after a 60 s treatment of egg surface using a cold plasma device set at 1 cm distance, 400 W power, and 35 L/min airflow with 65 % relative humidity. Moreover, our findings indicated no significant differences in egg quality, eggshell cuticle chemical composition, and cuticle coverage between untreated eggs and those treated with cold plasma. This suggests the potential of this non-chemical, non-thermal emerging technique to be commercialized as a substitute for conventional washing methods.

Visible-light-response Fe-doped BiOCl microspheres with efficient photocatalysis-Fenton degradation of antibiotics

The combination of photocatalysis and Fenton reaction has been considered as a promising technology for the removal of antibiotics from wastewater. In this study, the Fe-doped BiOCl was synthesized by solvothermal method for photocatalysis-Fenton degradation of levofloxacin (LEV). Fe/BiOCl exhibited a flower-like microsphere structure with the lattice doping of Fe3+ in BiOCl. Under the synergistic of visible light irradiation and H2O2, the excellent degradation performance of Fe/BiOCl towards LEV was achieved (97.8 %) after 100-min reaction at Fe-doping content of 5 % and H2O2 addition of 3 mM. The Fe deposition extended the light absorption range and reduced the recombination of photogenerated carriers. The photogenerated electrons could accelerate the cycling of Fe2+/Fe3+, and improve the utilization efficiency of H2O2. The hydroxyl radical (OH), superoxide radical (O2−) and holes (h+) played crucial roles during the photocatalysis-Fenton degradation of LEV. The present study provided valuable insights into the development of photocatalysis-Fenton synergy system for the effective decontamination of antibiotic wastewater.

Quorum quenching as a mechanism for Cu-bearing stainless steel to conduct nonbiocidal retardation of biofilm development

Bacterial contamination induced by stubborn biofilms has threatened many industries. Significant efforts have concentrated on mitigating surface-associated biofilms with focus on killing or removing bacterial cells, which are always short duration and suboptimal inhibition on biofilms. Here, we reported a sustainable and nonbiocidal strategy of control biofilms by applying a Cu-bearing stainless steel (SS) to interrupt quorum sensing (QS), mentioned as quorum quenching (QQ). It was found that Cu-bearing SS with the micro-galvanic couples structure consisting of the precipitated Cu-rich phases and the matrix triggers charge transfer reactions with bacteria/media, resulting in an overexpression of reactive oxygen species (ROS), which is responsible for QQ. Studies with luxS-delated mutant which cannot mediate the QS mechanism confirmed that QS could be the target for antibacterial metals to produce a sub-/non-lethal biofilm structural inhibition. And inducing ROS production has been a strategy to endow metals with QQ ability. Thereby, defective biofilms with the QS deletion phenotype would be gratifying to provide a sufficient window period for effective decontamination, curbing the solid surface as for contamination spreader. This research introduces a promising and practical QQ strategy for combating bacterial contamination from the root in active microbial environments, providing insights into the material modifications.

Effect of dielectric barrier discharge high voltage atmospheric cold plasma on Aspergillus flavus inactivation and aflatoxin B1 degradation on inoculated raw peanuts

High voltage atmospheric cold plasma (HVACP) is an emerging non-thermal technology with short treatment time, low energy consumption, and no chemical residues on foods. Peanut samples inoculated with Aspergillus flavus spores and spiked with Aflatoxin B1 (AFB1) toxin were treated with HVACP at 90 kV for 2, 5, and 10 min, and post-treatment storage times (0, 4, and 24 h) using air with different relative humidities (RH, 5, 40, and 80 %), respectively. A treatment of 5 min resulted in a 2.20 log spores reduction of A. flavus spores on peanuts. A. flavus was almost completely inactivated (99.9 %) by HVACP treatment for 10 min with 80 % RH in the air and 24 h post-treatment storage. A 71.3 % AFB1 reduction was achieved with a treatment of 2 min and 80 % RH without post-treatment. The reduction of AFB1 toxin also significantly increased with increasing treatment time, higher RH and post-treatment storage (p < 0.05). HVACP is a promising technology to effectively inactivate A. flavus and reduce AFB1 on raw peanut kernels without adversely affected peanut quality. Industrial relevanceTo improve the food safety and quality, it is crucial to develop an effective microbial decontamination approach while having minimal impact on the organoleptic characteristics and nutritional value of treated foods. Peanuts are an excellent source of plant-based protein, but they are highly susceptible to contamination with Aspergillus spp. mold, which may lead food safety issues. Cold plasma as an emerging non-thermal technology with short treatment time, low energy consumption, and no chemical residue on the food proves to be a promising tool to effectively inactivate A. flavus and reduce AFB1 on raw peanut kernels without adversely affected peanut quality.

Magnetic Hydrogel Microbots for Efficient Pollutant Decontamination and Self-Catalyzed Regeneration in Continuous Flow Systems.

The efficient removal of organic pollutants from water is crucial for protecting human health and the ecosystem. While adsorbent-based approaches offer advantages over traditional chemical and thermal methods, they still suffer from slow adsorption kinetics, high energy demand, and limited material lifespan. Herein, an efficient decontamination platform is introduced, using magnetic hydrogel microbots (MHMs) made from picolitre-sized hydrogel droplets coated with multifunctional magnetic nanoparticles. This approach includes 1) dividing a droplet into smaller microbots to enhance their interaction with sample solution and 2) dynamically spinning these MHMs to generate hydrodynamic flows that actively draw pollutants toward the embedded hydrogel for capture. The MHMs show high decontamination effectiveness in both bulk and continuous flow setups, achieving ≈95% removal efficiency within 3min. Further integrating MHMs with a non-pressurized fluidic platform enables energy-efficient continuous flow decontamination, removing ≥95% total organic carbon from a complex pollutant mixture at a flow rate surpassing other recent designs. Additionally, the MHMs facilitate self-catalyzed regeneration using an environmentally friendly H2O2 precursor, allowing for long-term and repeated usage. By enabling the unique divide-and-arrest decontamination of toxic pollutants, the multifunctional design holds tremendous promise for on-site wastewater treatment to ensure safe water access for everyone, even in resource-limited environments.

Experimental assessment of counterfog bioaerosol fast sampler for virus detection and decontamination

The respiratory system is equipped with several defence mechanisms to protect the body from microorganisms and airborne pathogens. There are situations where the respiratory system can be overwhelmed or compromised and infection happens, especially in individuals with weakened immune systems. Airborne pathogens are a serious risk for human and animal health, as exemplified by the challenges faced during the COVID-19 pandemic. The list includes viruses of varying severity such as Influenza virus, SARS-CoV-2, measles virus, Varicella-Zoster Virus, or Respiratory syncytial virus among others. Smaller particles can remain suspended in the air for longer periods and may reach the lower respiratory tract, including the alveoli in the lungs. The real-time detection of these pathogens in the air presents a significant challenge. The aerosols, especially those carrying viruses, are so small that they often elude conventional air samplers, making it difficult both to detect their presence and to remove them effectively from the air. This work introduces a recent technique designed for rapid aerosol sampling, with a particular emphasis on virus sampling. The system underwent calibration using artificial ɸ29 virus aerosols and was subsequently tested with naturally emitted aerosols of SARS-CoV-2. A series of tests were conducted in diverse settings, including hospitals, farms, offices, and railway cars. The equipment is also capable of swiftly removing bioaerosols from the air, thereby facilitating effective decontamination. The relevance of this technology lies in its capability for swift detection and elimination of viruses and other kinds of aerosols from air, facilitating prompt decision-making during high-risk events.

Zirconium-based nanoclusters as molecular robots for water decontamination

Water contamination owing to anionic pollutants is a persisting and ubiquitous global threat. The current remediation technologies are mostly low in efficiency, expensive in materials and often associated with complicated processes. Herein, we report a characteristic zirconium-based nanocluster that can work as molecular robots for the efficient remediation of anions-contaminated water with great effectiveness and molecular-level accuracy. It exhibits a stimuli-responsive behavior to facilitate the water treatment process: dissolve in acidic aqueous solutions for molecular-level decontamination and quickly aggregate for post-remediation collection. It can precisely capture the representative anionic pollutants, whilst featuring satisfactory capacities (ca. 175 mg-arsenic/g, 60 mg-chromium/g, 45 mg-fluoride/g, 70 mg-phosphorus/g, respectively), super-fast kinetics (finishing uptake within seconds, which is two to four orders of magnitude faster than typical sorbents), as well as multi-cycle applications without appreciable loss of activity. The coexisting common ions show no effect on the target uptake. The responsible active site investigation shows that four active sites are responsible for the monovalent pollutant removal, and the active sites work in pairs to capture divalent chromate species. Cost analysis shows its economical applicability in practical applications. This work would lead to the development of effective water decontamination with higher effectiveness, more convenience, lower cost and more practical application value.

Effective Decontamination Methods for Shiga Toxin-producing Escherichia coli on Beef Surfaces for Application in Beef Carcass Hygiene

Effective methods for decontamination of Shiga toxin-producing Escherichia coli (STEC) on beef were evaluated by 48 mL spraying, 100 mL, and 500 mL flushing with ethanol, hydrogen peroxide, peracetic acid, acidified sodium chlorite, and sodium hypochlorite in this study. The flushing with 500 mL of 1,000 ppm peracetic acid was most effective, reducing pathogens by 2.8 log CFU/cm2, followed by 1,200 ppm acidified sodium chlorite. The spraying with 1,000 ppm peracetic acid reduced pathogens by 1.6 log CFU/cm2. The flushing with 500 mL of 200 and 500 ppm acidified sodium chlorite, and 50, 100, 200, and 500 ppm peracetic acid significantly reduced the STEC population compared with those treated with distilled water (p < 0.05), reducing pathogens by 2.1, 2.4, 1.6, 1.8, 2.1 and 2.4 log CFU/cm2, respectively. Additionally, the flushing with 500 mL of 200 and 500 ppm acidified sodium chlorite significantly changed the color of beef samples (p < 0.05), whereas 100–500 ppm peracetic acid did not significantly change the color (p > 0.05). The flushing with 500 mL of 200 and 500 ppm acidified sodium chlorite and 200 and 500 ppm peracetic acid significantly changed the odor of beef samples compared with those treated with distilled water (p < 0.05). There was no difference in the reduction of STEC population between peracetic acid treatment at 25 °C and 55 °C, with or without washing with sterilized distilled water after decontamination. Washing with distilled water after flushing with peracetic acid tended to reduce the odor of the samples. These results suggest that treatment with 100, 200, and 500 ppm peracetic acid, followed by washing with distilled water, might reduce the STEC population without retaining the odor of the sanitizer.

Theoretical simulation study of laser-induced plasma bombardment on bacteria

With the rapid advancement of laser decontamination technology and growing awareness of microbial hazards, it becomes crucial to employ theoretical model to simulate and evaluate decontamination processes by laser-induced plasma. This study employs a two-dimensional axisymmetric fluid dynamics model to simulate the power density of plasma bombardment on bacteria and access its decontamination effects. The model considers the transport processes of vapor plasma and background gas molecules. Based on the destructive impact of high-speed moving particles in the plasma on bacteria, we investigate the bombardment power density under various conditions, including different laser spot sizes, wavelengths, plate’s tilt angles, and plate-target spacing. The results reveal that the bombardment power density increases with a decrease in laser spot size and wavelength. For instance, when the plate is parallel to the target surface with a 1 mm spacing, the bombardment power density triples as the laser spot size decreases from 0.8 mm to 0.5 mm and quadruples as the wavelength decreases from 1064 nm to 266 nm. Notably, when the plate is parallel to the target with a relatively close spacing of 0.5 mm, the bombardment power density at 0° inclination increases sevenfold compared to 45°. This simulation study is essential for optimizing optical parameters and designing component layouts in decontamination devices using laser-induced plasma. The reduction of laser spot size, wavelength, plate-target spacing and aligning the plate parallel to the target, collectively contribute to achieving precise and effective decontamination.

Comparison of the efficacy of Er,Cr:YSGG laser on oral biofilm removal from implant surfaces with various application times for the treatment of peri-implantitis defects: ex vivo study

PurposeThe major struggle in peri-implantitis therapy is the availability of successful decontamination of the infected implant surface. The main hypothesis of this study was the Er,Cr: YSGG laser decontamination efficacy investigation on the infected implant surfaces with various peri-implantitis defects. The primary objective of this study was to decide the efficacy of Er,Cr:YSGG laser as a decontamination tool at various peri-implantitis simulating defects. The secondary objective was to compare the efficacy of the Er,Cr: YSGG laser on oral biofilm removal between two protocols the first protocol (4 cycles at 2.5 min) and the second protocol (5 cycles at 5 min) at various peri-implantitis simulating defects.Materials and methodsA total of 3 subjects whose plaque biofilms formed in-vivo on twenty-four tested implants were divided into four tested groups. Two native implants were tested as controls.The in vitro defect model was computer‐aided designed and printed into a 3D-printed model with various anulations in peri-implant infrabony defects, which were 15,30,60,and 90 degrees.ResultsBoth Er, Cr: YSGG decontamination protocols at 50 mJ (1.5 W/30 Hz), 50% air, and 40% water were effective at reducing the total implant surface area/ biofilm ratio (%), but the second protocol had a markedly greater reduction in the duration of application (5 cycles at 5 min) than did the first protocol (4 cycles at 2.5 min).ConclusionThe Er, Cr: YSGG laser is an effective decontamination device in various peri-implantitis defects. The second protocol(5 cycles at 5 min) with greater application time and circles is more effective than the first one. The defect angulation influence the decontamination capability in peri-implantitis therapy.Clinical relevance (Scientific rationale for study)Clinicians anticipate that the exploration of suitable therapeutic modalities for peri-implantitis therapy is limited by the obvious heterogeneity of the available evidence in the literature and need for a pre-clinical theoretical basis setup. The major challenges associated with peri-implantitis therapy include the successful decontamination of the infected implant surface, the absence of any damage to the treated implant surface with adequate surface roughness, and the biocompatibility of the implant surface, which allows osteoblastic cells to grow on the treated surface and is the key for successful re-osseointegration. Therefore, these are the expected empirical triads that need to be respected for successful peri-implantitis therapy. Failure of one of the triads represents a peri-implantitis therapeutic failure. The Er, Cr: YSGG laser is regarded as one of the expected devices for achieving the required triad.Trial registration"Efficacy of Er,Cr YSGG Laser in Treatment of Peri-implantitis". ClinicalTrials.gov ID NCT05137821. First Posted date: 30 -11–2021.

The Antibacterial Efficacy of Far-UVC Light: A Combined-Method Study Exploring the Effects of Experimental and Bacterial Variables on Dose-Response.

Far-ultraviolet C light, with a wavelength of 200-230 nm, has demonstrated broad-spectrum germicidal efficacy. However, due to increased interest in its use as an alternative antimicrobial, further knowledge about its fundamental bactericidal efficacy is required. This study had two objectives. Firstly, it investigated experimentally the Far-UVC dose-response of common bacteria suspended at various cell densities in transparent buffer, ensuring no influence from photosensitive suspending media. Increasing doses of Far-UVC were delivered to Enterococcus faecium, Escherichia coli, Pseudomonas aeruginosa and Staphylococcus aureus in PBS at 101, 102, 103, 105 and 107 CFU·mL-1, with surviving colony-forming units enumerated (n ≥ 3). Secondly, through a systematised literature review, this work sought to explore the impact of genus/species, Gram type, cell form, cell density and irradiance on dose-response. The screening of 483 publications was performed with 25 included in the study. Data for 30 species were collated, analysed and compared with the experimental results. Overall, Gram-positive species showed greater resilience to Far-UVC than Gram-negative; some inter-species and inter-genera differences in resilience were identified; endospores were more resilient than vegetative cells; the results suggested that inactivation efficiency may decrease as cell density increases; and no significant correlation was identified between irradiance and bactericidal dose effect. In conclusion, this study has shown Far-UVC light to be an effective decontamination tool against a vast range of bacterial vegetative cells and endospores.