Sterilizer Research Articles

Archimedean [formula omitted]-norm and [formula omitted]-conorm based intuitionistic fuzzy WASPAS method to evaluate health-care waste disposal alternatives with unknown weight information

Health-care waste (HCW) contains numerous hazardous, infectious, and radioactive contents that may cause serious health issues for society and drastic environmental problems. Therefore, it is crucial to dispose of HCW safely and appropriately. Four commonly used HCW disposal methods are incineration, steam sterilization, microwave, and landfill disposal. To select an appropriate HCW disposal method, there are several conflicting criteria. Furthermore, when information is lacking due to uncertainty and criteria weighing conditions are also unknown, the decision to choose an appropriate HCW disposal method becomes more challenging. So, the objective of this paper is to introduce a novel integrated multi-criteria group decision-making (MCGDM) approach to evaluate HCW disposal methods in which incomplete information is quantified using intuitionistic fuzzy sets (IFSs), unknown criteria weights are evaluated using the maximizing deviation method, and the evaluation of HCW disposal methods is done by applying the Archimedean t-norm and t-conorm-based interactive intuitionistic fuzzy weighted aggregated sum product assessment (WASPAS) method. Herein, the Archimedean t-norm and t-conorm cover a wide range of t-norms and t-conorms, including the Algebraic, Einstein, Hamacher, and Frank, etc., by adopting prescribed combinations of additive generators. The proposed MCGDM approach has been applied to evaluate the above-listed four HCW disposal methods for a case study conducted by Mishra et al. (2020) in the context of India. A sensitivity analysis is performed to examine the impact of changes in the parameters involved in the proposed MCGDM approach. A comparative study is also performed with some well-known multi-criteria decision making(MCDM) and MCGDM methods to demonstrate the consistency and stability of the proposed approach. Findings suggest that the newly developed MCGDM approach is more general, flexible, and provides realistic results to evaluate HCW disposal methods under uncertainty and unknown criteria weight information.

Analysis of alternate material Onyx™ for total knee arthroplasty instrumentation sets.

A 25-pound weight limit is currently set on containerized instrumentation sets by the Association of periOperative Registered Nurses (AORN) and the Association for the Advancement of Medical Instrumentation (AAMI), in order to reduce strain on the staff and ensure that the sets are not too crowded in order to preserve sterilization and drying of the instruments. This is pushing companies to reduce the weight and number of instrumentation sets for the operating room. One solution has been to explore the viability of new, lighter materials such as Onyx. The goal of this study is to evaluate the novel material Onyx as a viable material utilized in reusable total knee arthroplasty (TKA) instrumentation sets utilizing traditional steam sterilization as the sterilization method. Mechanical and biocompatibility tests according to the American Society for Testing Materials (ASTM) and International Organization for Standardization (ISO) 10,993 were run to evaluate the Onyx Material to see if it would be a viable alternative to the stainless and martensitic steel that is currently being utilized. Gross warping and cracking after 10 rounds of sterilization was observed. This was qualitatively worse in the Onyx without a carbon fiber component. The Onyx material did not meet biocompatibility standards for its application. Onyx was determined to not be a viable material for TKA instruments regarding multiple high-pressure and -temperature sterilizations and cytotoxic cell testing.

Effect of Sterilization on the Dimensional and Mechanical Behavior of Polylactic Acid Pieces Produced by Fused Deposition Modeling.

To successfully implement additive manufacturing (AM) techniques for custom medical device (MD) production with low-cost resources, it is imperative to understand the effect of common and affordable sterilization processes, such as formaldehyde or steam sterilization, on pieces manufactured by AM. In this way, the performance of low-risk MDs, such as biomodels and surgical guides, could be assessed for complying with safety, precision, and MD delivery requirements. In this context, the aim of the present work was to evaluate the effect of formaldehyde and steam sterilization on the dimensional and mechanical stability of standard polylactic acid (PLA) test pieces produced by fused deposition modeling (FDM). To achieve this, PLA samples were sterilized according to the sterilization protocol of a public hospital in the city of Bucaramanga, Colombia. Significant changes regarding mechanical and dimensional properties were found as a function of manufacturing parameters. This research attempts to contribute to the development of affordable approaches for the fabrication of functional and customized medical devices through AM technologies, an issue of particular interest for low- and middle-income countries.

Effect of Sterilization on Bone Implants Based on Biodegradable Polylactide and Hydroxyapatite.

Medical devices intended for implantation must be, in accordance with the legal provisions in force in the European Union, sterile. The effect of sterilization on the structural and thermal properties of implants, made by 3D printing from biodegradable polylactide and hydroxyapatite in a proportion of 9/1 by weight, was evaluated. The implants were sterilized using three different methods, i.e., steam sterilization, ethylene oxide sterilization, and electron beam radiation sterilization. As a result of the assessment of the structural properties of the implants after sterilization, a change in the molecular weight of the raw material of the designed implants was found after each of the performed sterilization methods, while maintaining similar characteristics of the thermal properties and functional groups present.

Bifunctional photothermal membrane for high-temperature interfacial solar steam generation and off-grid sterilization

High-temperature solar steam generation is a promising sustainable strategy to alleviate the global clean water shortage. However, it is challenging to scale up the high-temperature steam generation under ambient conditions for water purification and steam sterilization simultaneously. Herein, we develop a solar-powered steam generating system to produce high-temperature steam for interfacial solar steam evaporation and off-grid sterilization. A three-layered photothermal membrane made of polystyrene foam, bubble wrap, and reduced graphene oxide (rGO) coated cloth produces high-temperature steam that can be condensed to clean water as well as sterilize microbes efficiently. The hybrid device configuration and higher solar light-absorbing capability of rGO result in high temperature steam generation (∼90 °C) to sterilize microorganisms such as S.aureus, E.coli, and G.stearothermophilus. Such a bifunctional device with high temperature steam generation and solar-steam evaporation capability could be a promising development for sustainable clean water generation and sterilization in remote areas.

The Effect of Sterilization on the Accuracy and Fit of 3D-Printed Surgical Guides.

This study was conducted to evaluate the accuracy of 3D-printed surgical guides before and after sterilization in a steam sterilizer. A test-model incorporating three implant replicas was customized. A total of forty guides were printed from five printable resins. A group made from a self-curing composite served as control group. The guides were checked for fit. Vertical discrepancies between the model and guides were measured at standardized points at a load of 500 g (P1). The guides were connected to implant replicas and scanned, and their angles were digitally measured. The specimens were sterilized in a steam sterilizer at 121 °C for 20 min at 2 bar pressure. Vertical discrepancies (P2) and angulations were remeasured. Additionally, the specimens were repositioned with an increased load, and measurements were repeated (P3). All specimens were repositionable after sterilization. The smallest variation in discrepancy at a 500 g load was 428 µm, whereas the greatest was 1487 µm. Under an increased force, the smallest change was 94 µm, while the greatest was 260 µm. The level of significance α = 0.05 (95% confidence interval) was set for all tests. The variation in the measured angles was not statistically significant (Kruskal-Wallis's test, p > 0.05). The accuracy was affected by the material and sterilization, but it was clinically acceptable when an increased load was applied during repositioning.

A copolymer derivative of poly(4-vinylpyridine propylsulfobetaine) for the design of thermostable bioinert poly(vinylidene difluoride) microporous membranes by vapor-induced phase separation

Most antifouling membranes lose their bioinert properties after steam sterilization because common antifouling materials are sensitive to hydrolysis. Here, we synthesized a random zwitterionic copolymer containing poly(styrene), poly(ethylene glycol) methyl ether methacrylate and zwitterionic poly(4-vinylpyridine propylsulfobetaine). The resulting copolymer, poly(styrene-r-EGMA-r-4VPPS), was blended with poly(vinylidene difluoride) to form bi-continuous and bioinert PVDF membranes by vapor-induced phase inversion. The copolymer drastically enhanced the hydrophilicity of the membranes, as water could wet the porous substrate entirely (WCA 0 for the zwitterionic membrane vs. about 144° for the virgin membrane). When exposed to Escherichia coli, Stenotrophomonas maltophilia, whole blood or HT1080 cells, fouling on the non-sterilized modified membranes was reduced by 95 %, 98 %, 99 % and 99 %, respectively. After sterilization, the antifouling properties were maintained. Results of cyclic water/Escherichia coli filtrations indicated that the non-sterilized modified membrane showed a flux recovery ratio of 57 %, against 21 % for a commercial membrane. Importantly, these performances were maintained after sterilization. The copolymer is not only efficient at mitigating biofouling in various situations, but also shows stable properties after autoclaving, which is paramount for membranes to be applied in the biomedical field.

Emergency Preparedness: Strategies for Maintaining Water Supply Quality and Access for Sterile Processing.

Sterile processing department (SPD) technicians are responsible for providing properly reprocessed surgical instruments for procedures. They use utility (ie, tap) water for precleaning, cleaning, and disinfection; and critical (ie, treated to remove impurities) water for the final rinse and steam sterilization. Water maintenance personnel should work with SPD personnel to ensure that the facility's water supply meets the quality parameters for hardness, pH, conductivity, chlorides, bacteria, and endotoxins. Inadequate water quality and quantity can affect SPD technicians' ability to reprocess instruments correctly and may result in pathogen transmission. When water quality concerns arise, SPD personnel should notify perioperative personnel. Health care facilities should have a water management program to address both normal and abnormal water operations and an emergency water supply plan. Pandemics, geopolitical conflicts, and natural disasters may disrupt water supplies. Proactive planning for water shortages should help facility leaders respond quickly and effectively when shortages occur.

The influence of water-cement ratios and alumino-silicate based accelerator on the properties of fiber-reinforced cement composites

Due to more strict environmental protection and greenhouse gas reduction, it is very important for all industries to appropriately manage their energy consumption. Fiber- reinforced cement composites are the popular building materials which consume enormous energy to intensify its chemical reaction during the autoclave steam curing process. Utilization of chemical admixture to replace the conventional energy-driven autoclave steam curing process will support the fiber- reinforced cement composites industry to develop sustainable building materials. In this research, typical and mechanical properties of the air-cured fiber- reinforced cement composites incorporated with alumino-silicate based accelerator were investigated. The results show an excellent positive correlation between the water-cement ratio of the mix design and the mechanical strength which is the optimum water-cement ratio for this FRCC are 0.53. Moreover, the properties of fiber- reinforced cement composites cured by either the autoclave steam curing process or air-curing process are comparable.

Numerical modelling of the evaporative cooling effect on solid walls in steam sterilisers

Steam sterilisation is based on high heat transfer rates which occur during the condensation of steam on medical devices or the steriliser walls themselves. To ensure these high heat transfer rates, non-condensable gases (NCGs) such as air must be removed from the chamber. One method is to extract the NCGs by using vacuum pumps. Due to the reduction in pressure, the saturation temperature drops as well, causing water droplets to evaporate; thus, the walls and loads cool down. This mechanism was investigated using a three-phase CFD model. A highly time-efficient heat transfer model for the evaporation process was developed as a result of this investigation. Evaporative cooling effects on the steriliser walls could be achieved by using a mass source term which varied in terms of time and space. Our results indicate that the model can be used to predict the temperatures of the fluid as well as the solids in a numerically inexpensive manner. In addition, this model allows the user to predict whether surfaces can be completely dried, an aspect which is crucial for ensuring the quality of a sterilisation process. The model created allows researches to simulate the entire sterilisation cycle, addressing a previously existing knowledge gap. Furthermore, the presented methods are also suitable for use in other industrial applications where condensation and evaporation effects on solids need to be effectively and inexpensively determined.

Применение автоматического парового стерилизатора для обеззараживания отходов иммунобиологического производства, контаминированных патогенными биологическими агентами

One of the ways to neutralize immunobiological production waste is their treatment in sterilizers with saturated water vapor under pressure. Currently, medical and pharmaceutical industries and laboratories use sterilizers with sterilization and disinfection programs preset by manufacturers. Decontamination modes are defined in Federal sanitary rules, norms and hygienic standards, SanPiN 3.3686-21, while the parameters of preliminary phases of the cycle must be tested experimentally and validated for specific conditions. Within the frames of this study, we have tested the modes of disinfection of an automatic steam sterilizer by the example of waste products from the production of cholera vaccine and anti-rabies immunoglobulin manufactured by the FSSI Russian Anti-Plague Institute «Microbe» of the Rospotrebnadzor. The wastes are used nutrient media, carcasses of laboratory animals (rabbits) and consumables. The chamber was loaded with «clean» objects in quantity and configuration, repeating the loading of material with pathogenic biological agents (PBA). The mode of inactivation inside the chamber and the objects was controlled by physical, chemical and biological methods. Based on the results of the experiments, corrective actions were taken to change the program and design of containers for autoclaving. It was concluded that the default disinfection programs set by manufacturers do not fully take into account specific conditions and need to be adjusted with further validation. It is necessary to develop standard operating procedures for personnel involved in the decontamination of pathogenic materials, in which should be stated the order of placement of objects and the means of control in the containers with PBA and the sterilizer chamber. Keywords: steam sterilizers, pathogenic biological agents, disinfection with saturated water vapor, phases of the steam disinfection cycle, validation.

Effects of ultrasound combined technology on quality and volatile compound properties of chili sauce

In this study, the effect and mechanism of seven kinds of sterilization treatments, including ultrasound (US), pasteurization (PT), high temperature short time (HTST), hot air (HA), microwave (MW), ultraviolet (UV) and steam sterilization, on E. coli, S. aureus and P. aeruginosa were investigated. It was found that PT, HTST, MW, and steam sterilization gave ideal bactericidal effect and were subsequently, combined with ultrasound treatment and applied to chili sauce. The results showed that ultrasound combined with microwave (US + MW) treatment was effective in preserving the maximum nutritional value and flavor of chili sauce while ensuring its sterility. The total number of colonies and coliforms were not detected after US + MW treatment. Furthermore, the contents of total polyphenol, capsaicin and 2,2-diphenyl-1-picrylhydrazyl (DPPH) free radical scavenging ability in the US + MW group were 11.10%, 12.78% and 17.00% higher than those of traditional autoclave sterilization. In addition, polyphenol oxidase (PPO) activity was 2.04 times higher in the US + MW group compared to the autoclave sterilization group. Correlation analysis showed that total polyphenol and capsaicin were positively correlated with 2,2′-azino-bis(3-ethylbenzothiazoline)-6-sulphonic acid (ABTS) (correlation coefficients 0.90 and 0.76, respectively) and DPPH free radical scavenging ability (correlation coefficients 0.88 and 0.72, respectively). The results obtained from GC-MS showed that US + MW treatment could reduce the loss of volatile compounds and retained the original flavor of chili sauce. The content of diallyl disulfide was 1.8 times that of autoclave group. This study provides a new theoretical reference for sterilization and flavor preservation of chili sauce.

Investigating the energy, environmental, and economic challenges and opportunities associated with steam sterilisation autoclaves

Abstract Despite steam sterilisation in autoclaves being a common industrial method of sterilisation, very little research has been conducted into quantifying the resources these processes demand and their associated environmental impacts. This paper aims to investigate industrial steam sterilisation in autoclaves with particular application to the biopharmaceutical industry. A mathematical model of a steam autoclave was developed to examine relationships between load size, load material properties and autoclave capacity with energy consumption, environmental impact and cost of sterilisation. The two main energy requirements are thermal energy to produce the clean steam for sterilising, and electrical energy for the vacuum pump. The study showed that thermal energy is dominant, particularly as load increases. The percentage of the maximum load at which the autoclave is operated has a major impact on the specific energy requirement or the energy required to sterilise per unit mass of load. For a given autoclave, the energy requirement increases with increased load but the specific energy requirement decreases. This in turn impacts on the emissions and the energy cost. It is thus shown that it is much more energy efficient to operate at higher loads, making the autoclave much more energy and cost effective, and with less environmental impact. There is potential for applying the analysis presented in this work for conducting optimisation studies for determining the sizes of autoclaves that could minimise the energy requirement, environmental impact and economic cost (3E) of investments for specified load versus time profiles.

Patient-specific cylinder templates for hybrid interstitial vaginal brachytherapy: Feasibility of automated 3-D design, 3D printing, and dosimetric outlook

Delivering highly conformal treatment plans for high-dose rate vaginal brachytherapy using commercially available applicators can be challenging. A partially automated workflow is presented for the in-house modeling and 3D printing of patient-specific cylindrical templates (PSCTs), which facilitate placement of flexible intracavitary and interstitial needles. To demonstrate feasibility, we compare PSCT treatment plans to retrospective interstitial brachytherapy plans delivered at our center. PSCTs derived from these plans were 3D printed to test the validity of the auto-design process. To facilitate clinical implementation, we validated the steam sterilization compatibility of PSCTs printed using polyetheretherketone (PEEK). Plans for ten patients treated using a combination of vaginal cylinder and interstitial needles were compared to PSCT-based plans created for the same patient. DVH parameters for the HRCTV (V100, V150, V200, D90) and OARs (D2 cm3) were evaluated, as well as the number of needles used and the total interstitial length. Each planned PSCT was printed and compared to the intended needle geometry. 3D printed models were sterilization validated by an independent contractor for an autoclave protocol. PSCT plans demonstrated advantages over template based perineal BT in reducing the total interstitial needle length required while preserving or improving HRCTV and OAR dosimetry. All printed PSCTs matched planned geometry. PSCTs stand to be an alternative to current HDR-BT templates/applicators for patients with vaginal and locally recurrent endometrial cancers. Clinically equivalent or improved treatment plans can be created and devices to deliver these plans can be accurately printed and sterilized.

Effects of Steam Sterilization on the Properties of Stimuli-Responsive Polymer-Based Hydrogels.

Hydrogels based on stimuli-responsive polymers can change their characteristics in response to small variations in environmental conditions, such as temperature, pH, and ionic strength, among others. In the case of some routes of administration, such as ophthalmic and parenteral, the formulations must meet specific requirements, namely sterility. Therefore, it is essential to study the effect of the sterilization method on the integrity of smart gel systems. Thus, this work aimed to study the effect of steam sterilization (121 °C, 15 min) on the properties of hydrogels based on the following stimuli-responsive polymers: Carbopol® 940, Pluronic® F-127, and sodium alginate. The properties of the prepared hydrogels-pH, texture, rheological behavior, and sol-gel phase transition-were evaluated to compare and identify the differences between sterilized and non-sterilized hydrogels. The influence of steam sterilization on physicochemical stability was also investigated by Fourier-transform infrared spectroscopy and differential scanning calorimetry. The results of this study showed that the Carbopol® 940 hydrogel was the one that suffered fewer changes in the studied properties after sterilization. By contrast, sterilization was found to cause slight changes in the Pluronic® F-127 hydrogel regarding gelation temperature/time, as well as a considerable decrease in the viscosity of the sodium alginate hydrogel. There were no considerable differences in the chemical and physical characteristics of the hydrogels after steam sterilization. It is possible to conclude that steam sterilization is suitable for Carbopol® 940 hydrogels. Contrarily, this technique does not seem adequate for the sterilization of alginate or Pluronic® F-127 hydrogels, as it could considerably alter their properties.

Individual 3D-Printed Implants Made from a Copolymer of Vinylidene Fluoride with Tetrafluoroethylene: Studies of the Effects of Steam Sterilization on Structure and Toxicity

Individual 3D-Printed Implants Made from a Copolymer of Vinylidene Fluoride with Tetrafluoroethylene: Studies of the Effects of Steam Sterilization on Structure and Toxicity

Evaluation of cleaning and sterilization of liposuction cannulas after intentional contamination with human fat, Mycobacterium abscessus subspecies bolletii, and Geobacillusstearothermophilus

The complex design of cannulas is a major challenge for reprocessing due to the retention and accumulation of fat residues. To evaluate the cleaning of liposuction cannulas and the protective effects of the remaining fat residues on Mycobacterium abscessus subspecies bolletii (MASB) and Geobacillus stearothermophilus inactivation during steam sterilization. In phase 1, six standard operating procedures were evaluated for cleaning of liposuction cannulas. In phase 2, the sectioned lumens of the liposuction cannulas were contaminated with the largest and smallest volume of human fat found in phase 1, with the addition of MASB. In phase 3, the same volumes of human fat from phase 2 were used to contaminate paper strips containing G.stearothermophilus. In phase 1 the residual amount of fat ranged from 6 to 52mg. In phases 2 and 3, the minimum and maximum amounts of fat (6 and 50mg) protected micro-organisms during steam sterilization at 134°C for 1.5 and 3min. Effective cleaning and sterilization of liposuction cannulas intentionally contaminated with human fat, MASB and G.stearothermophilus could not be performed.

Autoclaving-Triggered Hydrogelation of Chitosan-Gluconic acid Conjugate Aqueous Solution for Wound Healing.

Moist wound healing is known to heal wounds faster than dry wound healing. Hydrogel wound dressings are suitable for moist wound healing because of their hyperhydrous structure. Chitosan, a natural polymer, promotes wound healing by stimulating inflammatory cells and releasing bioactive compounds. Therefore, chitosan hydrogel has great potential as a wound dressing. In our previous study, physically crosslinked chitosan hydrogels were successfully prepared solely by freeze-thawing of chitosan-gluconic acid conjugate (CG) aqueous solution without using any toxic additives. Furthermore, the CG hydrogels could be sterilized by autoclaving (steam sterilization). In this study, we showed that autoclaving (121 °C, 20 min) of a CG aqueous solution simultaneously achieved gelation of the solution and sterilization of the hydrogel. Hydrogelation of CG aqueous solution by autoclaving is also physically crosslinking without any toxic additives. Further, we showed that the CG hydrogels retained favorable biological properties of the CG hydrogels prepared by freeze-thawing and subsequent autoclaving. These results indicated that CG hydrogels prepared by autoclaving were promising as wound dressings.

Can Steam Sterilization Affect the Accuracy of Point-of-Care 3D Printed Polyetheretherketone (PEEK) Customized Cranial Implants? An Investigative Analysis.

Polyetheretherketone (PEEK) has become the biomaterial of choice for repairing craniofacial defects over time. Prospects for the point-of-care (POC) fabrication of PEEK customized implants have surfaced thanks to the developments in three-dimensional (3D) printing systems. Consequently, it has become essential to investigate the characteristics of these in-house fabricated implants so that they meet the necessary standards and eventually provide the intended clinical benefits. This study aimed to investigate the effects of the steam sterilization method on the dimensional accuracy of POC 3D-printed PEEK customized cranial implants. The objective was to assess the influence of standard sterilization procedures on material extrusion-based 3D-printed PEEK customized implants with non-destructive material testing. Fifteen PEEK customized cranial implants were fabricated using an in-house material extrusion-based 3D printer. After fabrication, the cranial implants were digitalized with a professional-grade optical scanner before and after sterilization. The dimensional changes for the 3D-printed PEEK cranial implants were analyzed using medically certified 3D image-based engineering software. The material extrusion 3D-printed PEEK customized cranial implants displayed no statistically significant dimensional difference with steam sterilization (p > 0.05). Evaluation of the cranial implants' accuracy revealed that the dimensions were within the clinically acceptable accuracy level with deviations under 1.00 mm. Steam sterilization does not significantly alter the dimensional accuracy of the in-house 3D-printed PEEK customized cranial implants.

Collagen Peptides-Minerals Complexes from the Bovine Bone by-Product to Prevent Lipids Peroxidation in Meat and Butter and to Quench Free Radicals—Influence of Proteases and of Steam Sterilisation

Food-grade animal by-products are a source of bioactive peptides that could be used as natural antioxidant compounds. Until now, only few studies have put attention to the research of the most effective enzyme(s), to the antioxidant power of collagen peptides in food matrix and to the consideration of a mineralized collagen tissue such as bone, in particular the bovine one. Hence, this study aimed to investigate the effect of enzymes of different origins (animal, plant and microbial) and the effect of processing parameters such as the enzyme-collagen ratio, the steam sterilisation, the concentration of peptides and the mixing of peptides obtained by different enzymes on their antioxidant activity. Low molecular weight peptides (<3000 Da) were produced by the hydrolysis of bovine bone collagen by bromelain, cathepsin B and collagenase B. The antioxidant activity towards lipids peroxidation in meat and butter and the quenching capacity toward free radical were assessed. The bone minerals calcium, magnesium and phosphorous were also present in solution. Peptides-minerals complexes showed a significant antioxidant activity, which depended on the enzyme and on the test used to measure the antioxidant power; collagenase B showed the highest antioxidant capacity, which was further improved by peptides mixing and concentration; sterilization had no adverse effect on the antioxidant capacity. The results of this study can corroborate that food-grade animal by-products, such as the bovine bone, could be valorised for high-value food and health application, which can contribute to a circular use of the agro-food resources.