Effective Sterilization Method Research Articles

Monolithic integration of deep ultraviolet and visible light-emitting diodes for radiative sterilization application

The demand for effective sterilization methods, particularly in the wake of the Covid-19 pandemic, has sparked interest in the use of deep ultraviolet (DUV) radiation for disinfection. The high risk of skin/eye exposure to the high-energy DUV radiation requires the integration of DUV and visible (VIS) LED chips to sterilize and indicate its operation simultaneously in the portable sterilization devices. However, conventional double-chip integration suffers from high power consumption and fabrication complexity. This study sets out to explore the monolithic integration of DUV and VIS LEDs for the radiative sterilization application. This is accomplished by cascading AlGaN/AlGaN/AlGaN multiple quantum wells (QWs) and GaN/InGaN/GaN QWs through the compositional grading AlGaN cascade region. The inevitable overflown electrons from DUV QWs are deliberately introduced into the VIS QWs, allowing for the electron–hole recombination and the simultaneous emission of VIS light. Both experiment and simulation results confirm the feasibility of the proposed dual-wavelength LED integration. The proposed DUV&VIS LED shows an external quantum efficiency and wall-plug efficiency of 2.03% and 1.54% at 40 mA, respectively. This study establishes a quantitative framework for the monolithic integration of DUV and VIS LEDs for radiative sterilization, which has the potential to replace the current technique of using discrete DUV and VIS double-chip configurations.

Benzalkonium Chloride and Benzethonium Chloride Effectively Reduce Spore Germination of Ginger Soft Rot Pathogens: Fusarium solani and Fusarium oxysporum.

Ginger soft rot is a serious soil-borne disease caused by Fusarium solani and Fusarium oxysporum, resulting in reduced crop yields. The application of common chemical fungicides is considered to be an effective method of sterilization, and therefore, they pose a serious threat to the environment and human health due to their high toxicity. Benzalkonium chloride (BAC) and benzethonium chloride (BEC) are two popular quaternary ammonium salts with a wide range of fungicidal effects. In this study, we investigated the fungicidal effects of BAC and BEC on soft rot disease of ginger as alternatives to common chemical fungicides. Two soft rot pathogens of ginger were successfully isolated from diseased ginger by using the spread plate method and sequenced as F. solani and F. oxysporum using the high-throughput fungal sequencing method. We investigated the fungicidal effects of BAC and BEC on F. solani and F. oxysporum, and we explored the antifungal mechanisms. Almost complete inactivation of spores of F. solani and F. oxysporum was observed at 100 mg/L fungicide concentration. Only a small amount of spore regrowth was observed after the inactivation treatment of spores of F. solani and F. oxysporum in soil, which proved that BAC and BEC have the potential to be used as an alternative to common chemical fungicides for soil disinfection of diseased ginger.

Hierarchical Cu dendrites@ CuO multifunctional nanowire mesh for solar-thermal clean water production

Solar-driven interfacial evaporation is recognized as an energy-efficient and sustainable approach to combat the global freshwater crisis, particularly in rural areas where continuous energy inputs are limited. Additionally, these regions often lack effective sterilization methods for their water sources. By incorporating photothermal materials with inherent antibacterial properties, water purification can be enhanced without relying on external sterilization steps. Herein, we designed a multi-functional photothermal (MFP) evaporator based on a Cu dendrite@ CuO with abundant nanowires via a template-free method for solar-thermal clean water production. Compared to flat-type structures, the MPF evaporator with its dendritic architecture not only exhibits efficient photon absorption but also expands the evaporation area by over sevenfold, facilitating enhanced water evaporation with an efficient pathway for water transfer. Under 1 kW m−2, the MFP evaporator achieves an impressive evaporation rate of 1.40 kg m−2 h−1 and an efficiency of 87.8 %. Furthermore, the MFP evaporator demonstrates remarkable antibacterial capabilities, effectively inhibiting bacterial growth in raw water by damaging bacterial cell walls. Hence, the as-prepared MFP evaporator exhibits tremendous potential as an innovative system for solar-driven interfacial water evaporation and purification.

UV-C irradiation as an effective tool for sterilization of porcine chimeric VP1-PCV2bCap recombinant vaccine

Ultraviolet irradiation is an effective method of virus and bacteria inactivation. The dose of UV-C light necessary for baculovirus inactivation by measurement of fluorescent GFP protein produced by baculovirus expression system after the irradiation of baculovirus culture in doses ranging from 3.5 to 42 J/m2 was determined. At a dose of 36.8 J/m2, only 0.5% of GFP-expressing cells were detected by flow cytometry and confocal microscopy. The stability of purified VP1-PCV2bCap protein produced by baculovirus expression system was analyzed after the irradiation at doses ranging from 3.5 to 19.3 J/m2. Up to the dose of 11 J/m2, no significant effect of UV-C light on the stability of VP1-PCV2bCap was detected. We observed a dose-dependent increase in VP1-PCV2bCap-specific immune response in BALB/c mice immunized by recombinant protein sterilized by irradiation in dose 11 J/m2 with no significant difference between vaccines sterilized by UV-C light and filtration. A substantial difference in the production of VP1-PCV2bCap specific IgG was observed in piglets immunized with VP1-PCV2bCap sterilized by UV-C in comparison with protein sterilized by filtration in combination with the inactivation of baculovirus by binary ethylenimine. UV-C irradiation represents an effective method for vaccine sterilization, where commonly used methods of sterilization are not possible.

The novel sterilization device: the prototype testing

Currently, there are numerous methods that can be used to neutralize pathogens (i.e., devices, tools, or protective clothing), but the sterilizing agent must be selected so that it does not damage or change the properties of the material to which it is applied. Dry sterilization with hydrogen peroxide gas (VHP) in combination with UV-C radiation is well described and effective method of sterilization. This paper presents the design, construction, and analysis of a novel model of sterilization device. Verification of the sterilization process was performed, using classical microbiological methods and flow cytometry, on samples containing Geobacillus stearothermophilus spores, Bacillus subtilis spores, Escherichia coli, and Candida albicans. Flow cytometry results were in line with the standardized microbiological tests and confirmed the effectiveness of the sterilization process. It was also determined that mobile sterilization stations represent a valuable solution when dedicated to public institutions and businesses in the tourism sector, sports & fitness industry, or other types of services, e.g., cosmetic services. A key feature of this solution is the ability to adapt the device within specific constraints to the user’s needs.

Enhanced delignification and production of bioactive compounds in wheat straw by optimizing sterilization methods for Irpex lacteus fermentation

This study aimed to examine the effects of sterilization methods on the degradation ability and bioactive compound production of Irpex lacteus in wheat straw. Following 28 days of fermentation, the lignin content of samples autoclaved and pasteurized at pH 4.5 was reduced by 16.0 % − 21.7 % compared to pasteurized samples without pH adjustment, accompanied by a significant increase in sugar yield ranging from 83.30 % − 96.35 %. Autoclaved samples exhibited the lowest total phenol content and antioxidant activity (P < 0.05). Bacillus occupied an absolute advantage (89.1 %) in samples pasteurized at pH 4.5, whereas 10 bacterial genera exhibited abundances above 1 % in pasteurized samples without pH adjustment. Furthermore, 45.1 % − 47.2 % of the metabolites comprised lipids and lipid-like molecules, and some of them were improved by pasteurization at pH 4.5. Overall, pasteurization at acidic conditions is an effective sterilization method for the fungal conversion of wheat straw.

Establishment and Optimization of Micropropagation System for Southern Highbush Blueberry

The optimization of micropropagation for blueberries is crucial due to the growing blueberry industry and demand for plantlets. This study focused on four stages: explant sterilization, in vitro establishment, in vitro proliferation, and ex vitro rooting, aiming to establish an efficient in vitro propagation system for southern highbush blueberry cultivar ‘ZY09’. The most effective explant sterilization method was a 60 s treatment with 75% ethanol and a 5 min treatment with 4% NaClO. During the establishment of the in vitro culture, the modified woody plant medium was found to be suitable. The replacement of NH4NO3 in woody plant medium with (NH4)2SO4 facilitated the proliferation of blueberry microshoots. The optimal combination of plant growth regulators for the in vitro proliferation of blueberry microshoots was indole-3-butyric acid (0.1 mg·L−1), thidiazuron (0.0005 mg·L−1), and zeatin (1 mg·L−1). Perlite was the most suitable substrate for ex vitro rooting. The best ex vitro rooting performance was observed without immersion in growth regulators. Indole-3-butyric acid enhances root formation and suppresses root elongation in blueberries. The findings of this study can be applied to large-scale in vitro propagation of southern highbush blueberry and provide a reference for the genetic transformation of blueberries.

Laser ablation of the equine oviductal papilla as a novel contraceptive technique

Reproductive control of wild horses has frustrated land management groups for decades. GnRH and Zona Pellucida vaccines have a limited duration of efficacy, intrauterine devices are unpredictably retained, and attempts to ovariectomize mares in the western United States were met with public outcry in 2018. The development of a non-surgical permanent sterilization technique has the potential to revolutionize management of wild equids on public lands. The objectives of this study were to develop a safe and effective sterilization technique for reproductively healthy mares. We hypothesized that laser ablation of the oviductal papillae would be an effective method of permanent sterilization. Seven light-breed reproductively healthy mares (5-21yrs) were enrolled in the study. On enrollment, mares were sedated for hysteroscopy, and the endometrium and oviductal papillae were examined using a 103cm flexible endoscope (Olympus GIF-160 Gastroscope, Center Valley, PA) attached to an Olympus EVIS EXERA CV-160 video processor. In five mares, a 600 μm laser fiber was advanced through the biopsy channel and a diode laser (Dornier Medilas D, Dornier MedTech America, Inc., Kenneasaw, GA) was used to deliver direct contact pulses of 3 to 5 seconds in duration to the oviductal papilla. The endoscope was then guided up the contralateral horn and the process repeated. In two control mares, the oviductalpapillae were visualized, but no laser ablation was performed. All mares received 5 mg dinoprost IM and a uterine lavage within 4 hours post-procedure. Transrectal ultrasound was performed every 2-3 days until a 35mm follicle was detected, and then mares were bred using semen from a fertile stallion. Pregnancy status was determined by transrectal ultrasound 14 days post-ovulation, luteolysis was induced, and mares were rebred on 2-4 consecutive cycles. Control mares conceived on 6 out of 9 cycles (67% pregnancy rate). Pregnancy rate was significantly lower in the treatment group (5%, 1 out of 20 cycles, p=0.003). The first mare that was laser ablated conceived on the 4th cycle, and repeat hysteroscopy determined that the left oviduct was not effectively ablated. The third mare was diagnosed with peritonitis via abdominocentesis 6 hours post hysteroscopy. The mare was treated with broad spectrum antibiotics and recovered uneventfully. Three mares were re-bred two years after the procedure and did not conceive. In conclusion, when laser ablation of the oviductal papillae was appropriately performed, scar tissue formation effectively prevented pregnancy for a minimum of four months post-procedure. Laser ablation of the oviductal papillae is a promising technique for permanent sterilization of the mare and a follow-up long-term fertility study is warranted in a larger group of mares is warranted.

Effects of Tea Polyphenols Combined with Thermosonication on the Population of Salmonella enterica in Fresh-Cut Wax Gourd during Storage and Its ANFIS Survival Model

Fresh-cut vegetables are exposed to the risk of Salmonella spp. contamination. Effective sterilization methods and early warning systems play important roles in ensuring food safety of fresh-cut products. The aim of this study was to evaluate the effect of tea polyphenols (TP) combined with thermosonication (TS) treatment on inactivation of Salmonella enterica in fresh-cut wax gourd and to develop and estimate models using adaptive neuro-fuzzy inference system (ANFIS) with different membership functions (MFs) for predicting S. enterica population during storage at 25, 10, and 4 °C, respectively. The results showed that both TP and TS treatment can effectively reduce the population of S. enterica in fresh-cut wax gourd. The combination of TP (1.0%) and TS (50 °C, 1 min) treatment followed by storage at 4 °C may be a suitable bacteriostatic scheme for the preservation of fresh-cut wax gourd. Fluorescence microscopy analyses indicated that TP and TS treatment could lead to the destruction of the cell membrane, followed by the leakage of cytoplasm, and, finally, cell death. ANFIS with the gaussmf function performed well in modeling and predicting the population of Salmonella in fresh-cut wax gourd and provided a powerful tool for modelling and predicting microbe population and the shelf life of food products.

High-Intensity Ultraviolet-C Irradiation Efficiently Inactivates SARS-CoV-2 Under Typical Cold Chain Temperature.

SARS-CoV-2 contaminated items in the cold chain becomes a threat to public health, therefore the effective and safe sterilization method fit for the low temperature is needed. Ultraviolet is an effective sterilization method while its effect on SARS-CoV-2 under low-temperature environment is unclear. In this research, the sterilization effect of high-intensity ultraviolet-C (HIUVC) irradiation against SARS-CoV-2 and Staphylococcus aureus on different carriers at 4°C and - 20°C was investigated. The results showed that dose of 15.3mJ/cm2 achieved more than 3 log reduction of SARS-CoV-2 on gauze at 4°C and - 20°C. The vulnerability of coronavirus to HIUVC under - 20°C was not significantly different than those under 4°C. Four models including Weibull, biphasic, log-linear tail and log linear were used to fit the survival curves of SARS-CoV-2 and Staphylococcus aureus. The biphasic model fitted best with R2 ranging from 0.9325 to 0.9878. Moreover, the HIUVC sterilization correlation between SARS-CoV-2 and Staphylococcus aureus was established. This paper provides data support for the employment of HIUVC under low-temperature environment. Also, it provides a method of using Staphylococcus aureus as a marker to evaluate the sterilization effect of cold chain sterilization equipment.

Investigation of bacteria and detergent residues on undergraduate students' dinner plates in dormitories during university lockdown.

The COVID-19 outbreak has disrupted undergraduate students' experiments since their access to the laboratory is limited. To address this problem, the bacteria and detergent residues on undergraduate students' dinner plates were investigated by the students in the dormitories. Five different types of dinner plates from 50 students were collected, which were cleaned with detergent and water in the same way and naturally dried. Then, Escherichia coli (E. coli) test papers and sodium dodecyl sulfonate test kits were used to understand the bacteria and detergent residuals. Commonly available equipment such as a yogurt maker was used for bacterial culture; detergent analyses were performed using centrifugation tubes. Effective sterilization methods and safety protection were achieved by dormitory available methods. According to the investigated results, the students found the differences in bacteria and detergent residuals between different dinner plates and made suitable choices for the future.

Infection Prevention Control (IPC), Hospital acquired infection (HAI) and Obstetrics practice

Infection prevention and control program is important to prevent infectious morbidity. Simple method like hand washing to effective sterilization methods are recommended in clinical practice. Immunocompromised state of pregnancy and newborn are more vulnerable to acquire infection; and there is a real challenge from hospital acquired infection because of surgical nature of obstetric care.

Effects of Different Culture Media Compositions on In Vitro Micropropagation from Paradox Walnut Rootstock Nodes

The aim of this study is to establish an effective protocol for in vitro micropropagation from node explants of the 'Paradox' (Juglans regia x J. hindsii) rootstock. In the first stage of the study, the node explants were cultured in semi-solid media after being exposed to different sterilization methods. The most effective sterilization method was observed as ST2 with the lowest darkening rate (4 %). According to the results, SP4 medium provided the highest number of shoots per unit explant (1.05 shoots/explant) and 100 % shoot formation, SP2 medium provided the best mean shoot length (1.6 cm) and the mean number of nodes per unit explant (7.95 nodes/explant). Best root induction was provided from ½ Modified MS medium containing 4 mg/L IBA with 30 g/L sucrose. For root induction explants were retained under dark conditions for 7 days at 24±2oC. In order to ensure root formation and elongation, shoot explants with root induction cultured in a 16-hour photoperiod (3500 lux) for 21 days in different nutrient media containing 2.4 mg/L Gelrite, hormone-free and mixed with vermiculite (1:1 v/v) and was rooting rate is 45.45 % in ¼DFe medium.

Utilizing Proteomic Approach to Analyze Potential Antioxidant Proteins in Plant against Irradiation.

Gamma-ray irradiation is an effective and clean method of sterilization by inactivating microorganisms. It can also be applied to induce anti-oxidants for future application. In this study, the mung bean (Vigna radiata) was exposed to gamma-ray irradiation under the dose of 0, 5 or 10 kGy. With increasing irradiation doses, the concentrations of malondiadehyde decreased while the levels of total flavonoids and DPPH (1,1-diphenyl-2-picrylhydrazyl) radical scavenging activity increased. It has been shown that consuming flavonoids can provide protective effects. In addition, proteomic analysis identified several proteins having anti-oxidant activities in the 5 kGy irradiated group. These proteins are Apocytochrome f, Systemin receptor SR 160, DELLA protein DWARF8, DEAD-box ATP-dependent RNA helicase 9, ζ-carotene desaturase (ZDS), and Floral homeotic protein AGAMOUS. Our findings indicate that plants contain a variety of phytochemicals and antioxidant proteins which may effectively prevent oxidative stress caused by irradiated peroxidation.

Is In-Service Granular Activated Carbon Biologically Active? An Evaluation of Alternative Experimental Methods to Distinguish Adsorption and Biodegradation in GAC.

In-service granular activated carbon (GAC) may transform into biological activated carbon (BAC) and remove contaminants through both adsorption and biodegradation, but it is difficult to determine its biodegradative capacity. One approach to understand the GAC biodegradative capacity is to compare the performance between unsterilized and sterilized GAC, but the sterilization methods may not ensure effective microbial inhibition and may affect adsorption. This study identified the 14C-glucose respiration rate as the best metric to evaluate the effectiveness of three sterilization methods: sodium azide addition, autoclaving, and γ irradiation. The sterilization protocols were refined, including continuously feeding 300 mg/L of sodium azide, three cycles of autoclaving, and 10-12 kGy of γ irradiation. Parallel minicolumn tests were conducted to identify sodium azide addition as the most broadly effective sterilization method with an insignificant effect on adsorption in most cases, except for the adsorption of anionic compounds under certain conditions. Nevertheless, this problem was solved by decreasing the azide dosage as long as it is still sufficient to provide effective microbial inhibition. This study helps to develop an approach that differentiates adsorption and biodegradation in GAC, which could be used by future studies to advance our understanding of BAC filtration.

Colonization of Pathogens in Earphones and Observation of Effective Sterilization Methods and Cycles

Colonization of Pathogens in Earphones and Observation of Effective Sterilization Methods and Cycles

A state-of-the-art guide to the sterilization of thermoplastic polymers and resin materials used in the additive manufacturing of medical devices

Continuous development of additive manufacturing technologies has reached new areas, including medical research and healthcare applications, where precision, highly accurate reproducibility, disinfection, or even sterility of the end product is essential. The study aims to critically evaluate the effect of different sterilization and disinfection methods for most commonly used additive manufacturing technologies and materials in medical device development: PLA (polylactic acid), PETG (polyethylene terephthalate glycol), ABS (acrylonitrile butadiene styrene), and HIPS (high impact polystyrene) for material extrusion technology (FFF; fused filament fabrication), polyamide (PA2200) for powder bed fusion technology (SLS; selective laser sintering), MED610™ for PolyJet™ material jetting, and standard Formlabs™ white resin (V4) for SLA (stereolithography) technology. The materials were tested before and after different sterilization and disinfection protocols, including treatment with 70% ethanol, chlorine solution, H2O2 plasma sterilization, autoclave and dry heat sterilization, applying 10 and 20 cycles in all cases. Bacteriostatic/fungistatic and sterility tests were performed using Escherichia coli, Enterococcus faecalis, and Candida albicans as reference strains. Cytotoxicity was evaluated using A549 cells. The samples showed significant structural or aesthetic alterations detected by various mechanical tests, scanning electron microscopy, or differential scanning calorimetry (DSC-TGA). No significant cytotoxic effect was revealed during the experiment. Our results can serve as a guide for the selection of effective sterilization and disinfection methods for the most common materials used in 3D printing in medical and healthcare applications.

Explant Sterilization Technique Castanopsis argentea (Blume) A.DC. with the addition of Ascorbic Acid and Sodium Hypochlorite (NaOCl) In Vitro

Castanopsis argentea (Blume) A.DC. has the local name saninten. This plant is one of the woody plants that has the potential to be developed because it is beneficial for wildlife to nest and is used in reforestation. The seeds of this plant can be used for food by boiling and burning. This plant must be preserved so that it does not become extinct. However, the propagation, so it must use the technique of propagation through tissue culture. This study aims to determine the best sterilization technique for in vitro culture of C. argentea. Eight methods of explant sterilization have been carried out in this study. Methods 1-4 do not use ascorbic acid immersion, while methods 5-8 use the addition of ascorbic acid. Based on observations, it is known that the best sterilization is in the 8th method because the level of contamination and browning is lower than other methods, namely on the fifth day after planting only 20%. The 8th method is graded sterilization. In graded sterilization, explants were gradually immersed in 10% NaOCl, 20% NaOCl, and 30% NaOCl, respectively. Multilevel sterilization is the most effective method of sterilization to reduce contamination and browning. Ascorbic acid acts as an antioxidant and reduces contamination in the enzymatic browning reaction. The combination of sterile substances, time, sequence, and method of immersion affects the sterility of explants.

The influence of UV irradiation on fish skin collagen films in the presence of xanthohumol and propanediol

Fish skin collagen films are widely used as adhesives in medicine and cosmetology. Ultraviolet (UV) irradiation can be considered as an effective sterilization method for biomaterials, however, it may also lead to material photodegradation. In this work, the influence of xanthohumol and propanediol on the physico-chemical properties of collagen films before and after UV irradiation was studied.Collagen for this research was extracted from silver carp skin and thin films were fabricated by the solution casting methods.The structure of films was researched using infrared spectroscopy. The surface properties of films were investigated using Atomic Force Microscopy (AFM) and contact angle measurements. Mechanical properties were measured as well. It was found that the addition of xanthohumol and propanediol modified the roughness of collagen films and their mechanical properties. UV irradiation led to the water loss from the film and modification of the collagen structure.In the presence of propanediol and xanthohumol the water loss after UV irradiation was smaller than in UV-irradiated collagen films without these additives.

Obtainment of bacterial cellulose with added propolis extract for cosmetic applications

AbstractBacterial cellulose (BC) is a versatile material produced by microorganisms in the form of a hydrogel film with high water retention capacity, porosity, and mechanical strength. BC can incorporate and release substances, making it an interesting polymer for use in the cosmetic and biomedical industries. The aim of the present study was to evaluate the use of a bacterium for the production of cellulose films in which propolis extract was added in situ and ex situ (during and after membrane production, respectively) with promising use as a skincare product. The bacterium Gluconacetobacter hansenii was grown in standard Hestrin–Schramm (HS) medium as well as HS medium with propolis extract for 7 days. A radiolytic process with 60Co was investigated as a safe sterilization method. The average yield was 120.55 ± 2.40 g of cellulose/L. The polymeric system exhibited antioxidant activity (15.16% inhibition of oxidant activity) and high water‐retention capacity (98.01 ± 0.17%). In conclusion, natural additives can provide the antioxidant characteristics of BC. Moreover, gamma irradiation proved to be an effective sterilization method, while maintaining the properties of the material.