Effect Of Sterilization Research Articles

Eucalyptus globulus essential oil thin film polymerized by cold plasma on Ti6Al4V: Sterilization effect, antibacterial activity, adhesion, and viability of mesenchymal stem cells

AbstractThis work aims to evaluate the characterization, antibacterial activity, and mesenchymal stem cell (MSC) viability in films obtained by cold plasma polymerization, from the essential oil of Eucalyptus globulus on Ti6Al4V alloy. The film presented low roughness values and a contact angle of 85°. The process incorporated a coating with oxygenated functional groups (OH and C═O). The effect of ultraviolet radiation, ethylene oxide, autoclave, and air plasma sterilization on polymer degradation was evaluated. Biofilm formation by Staphylococcus aureus was reduced on the film surface with no toxicity to MSCs. These effects can be attributed to functional groups, combined with the surface roughness and contact angle. These results suggest a potential for the application of this coating in biomaterials.

Effect of radiation sterilization on the ability to induce adipose regeneration in vivo in decellularized adipose-derived matrix.

Decellularized adipose-derived matrix (DAM), a biological scaffold that can induce adipose regeneration. The balance between its sterilization efficiency and its ability to maintain in situ adipose regeneration should be considered in terminal sterilization. The purpose of this study was to investigate the effects of radiation sterilization of cobalt-60 (60 Co)with different doses on adipogenesis induced by different forms of DAM, so as to reduce radiation dose under the premise of safe and effective sterilization and ensure adipogenesis induced by DAM in vivo. High dose (25kGy) and low dose (5kGy) radiation were used to sterilize freeze-dried and wet DAM, respectively. The sterilization efficiency, macro and micro characteristics, mechanical and mechanical properties of DAM were compared, and then implanted into the immunocompromised mice to evaluate the adipose regeneration. Under the two radiation doses, no microbial growth was found in the freeze-dried and wet DAM sterility tests, and no significant changes were observed in the macro and micro structures. In terms of mechanical properties, the elastic modulus of high dose freeze-dried DAM decreased significantly (p<0.001). In vivo animal experiments, the freeze-dried DAM irradiated with high dose almost completely lost its function of adipogenesis in vivo. Although the wet DAM irradiated with high dose could induce fat regeneration in the early stage, the adipocyte deformation and atrophy appeared in the later stage. The freeze-dried and wet DAM after low dose irradiation was similar to the wet DAM without irradiation in the blank control, which could maintain excellent adipogenic and angiogenic functions in vivo. High dose 60 Co irradiation can completely destroy the ability of freeze-dried DAM to induce adipose regeneration in situ, while low dose irradiation (5kGy) can effectively sterilize the DAM without damaging in vivo induced adipose regeneration. Radiation has more damage to freeze-dried DAM than wet DAM in adipogenesis properties.

Sterilization mechanism and nanotoxicity of visible light-driven defective carbon nitride and UV-excited TiO2

The sterilization effect of photocatalysis and biotoxicity of nanomaterial catalysts have attracted high attention. In this study, the novel visible-driven defective carbon nitride (VL/DCN) system exhibits non-photoreactivation, non-toxic superior performance compared with traditional ultraviolet radiation (UV) and UV/titanium dioxide (UV/TiO2). The inactivation of antibiotic-resistant bacteria (ARB) by novel VL/DCN still reached 7 log within 4 h, and the reduction rates of aminoglycoside gene strB and tetracycline gene tetA exceeded 0.8 log and 1.2 log, respectively. Further, the sterilization mechanism and nanotoxicity were contrastively and systematically analyzed among above three systems as following. Firstly, in the VL/DCN system, reactive oxygen species (ROSs) generated from photocatalytic process leads to the destruction of cell membranes, resulting in dissolving out of potassium ion (K+), protein and cell membrane ATP content. Thus, resistant bacteria were completely inactivated and photoreactivation disappears. In contrast, the UV only acted on bacterial DNA and existed the light resurrection. The UV/TiO2 strictly dependent on ultraviolet light and can be used in limited scenarios. Secondly, in cell viability analysis by human lung cell line BEAS-2B experiments, the 10% inhibition of cell growth when DCN was 600 mg/L much lower than 28% inhibition of cell growth when TiO2 was only 200 mg/L. The expression of pro-inflammatory cytokines ((Interleukin, IL) -6), IL-8, IL-1β) under the effect of DCN was 1.5-fold, 5.7-fold and 3.7-fold lower than TiO2, respectively. Meanwhile, DCN induced cells to produce less ROSs, malondialdehyde (MDA), and more superoxide dismutase (SOD). Above results demonstrated that DCN has far lower cytotoxicity than TiO2. This study provides theoretical support for the application of photocatalytic sterilization technology and the exploration of the toxicity of nanomaterials.

Photocatalytic production of H2O2 and its in situ sterilization over Zn-based ZIFs materials

In situ generation of H2O2 by photocatalyst with sterilization is an environmentally friendly method. In this work, we prepared three kinds of Zn-based ZIFs materials, i.e., MAF-6, ZIF-11 and ZIF-71, and systematically investigated their application in the area of photocatalytic H2O2 production, and antibacterial efficiency. It is found that MAF-6 had the best ability of generate H2O2 (1005 μmol h-1g-1), 1.6 times more than ZIF-11, while ZIF-71 produced almost no H2O2. The sterilization rate of MAF-6 against Staphylococcus aureus and Escherichia coli can reach 97% and 91% in 3 h, respectively. It is worth noting that the more photo-generated reactive oxygen species (∙OH and ∙O2-) are produced, the better sterilization effect. This work provides new material and insights into photocatalytic sterilization by in situ H2O2 generation.

Light-settable polybenzoxazines for marine antifouling coatings

Building benzoxazine coatings on large equipment is of great practical importance and challenging. In this work, a main-chain type benzoxazine (MCBZ) resin that can be quickly shaped under UV light was successfully synthesized and can be directly coated into a film. In addition, it had a wide processing window, low curing temperature, excellent static antifouling effect, and sterilization effect. The d12-DHBP-MCBZ resin was prepared from dodecamine, which ensured the sterilization effect, and 4, 4′-dihydroxy-benzophenone provided the photoinitiation sites and activated the oxazine ring. By adjusting the ratio of d12-DHBP-MCBZ to TMPTMA, hydrophilic benzoxazine coatings can be prepared, suitable for fouling-resisting coatings. The results indicated that the d12-DHBP-MCBZ resin could be quickly shaped under UV light, and the post-curing temperature was only 140 °C. In particular, the coatings' excellent hydrophilicity can effectively prevent fouling organisms' adhesion and improve the static antifouling effect. It was worth mentioning that Poly (BZ/20 %TMA) coating achieved a high sterilization performance of >99 %. These works gave us a new strategy to solve application problems of benzoxazine coatings on large equipment and antifouling coating efficiency problems.

A CASE STUDY OF CAT STERILIZATION IN KARANGWUNI, YOGYAKARTA: IMPACTS PERCEIVED BY CARETAKERS AND THEIR UNDERSTANDING OF THE PROGRAM

There is yet to be collected the number of cats in Indonesia, including free- roaming cats. Studies have shown that there is a connection between sterilization and free-roaming cats’ health and welfare. In 2021, Suara Suaka Indonesia decided to hold a small-scale sterilization program in a neighborhood called Karangwuni, Yogyakarta to contribute in lowering cat population. In this case study, we focus on the effect of sterilization to cats that are perceived by humans. Survey was done using Google Forms, taking information on their demographics, involvement with Suara Suaka Indonesia, feedback on their cats’ post-surgery changes and their understanding on sterilization. Respondents are generally satisfied with the impact sterilization has on them and their cats, this is supported by how they perceive sterilization as important and their willingness to recommend the procedure to other people. However, there can still be improvement on delivering messages of sterilization to ensure that the purpose, process, and impact of sterilization can be adequately understood by all participants of the program.

Development and evaluation of an intelligent UVC sterilization system for raw aquatic food production

AbstractRaw aquatic food is regarded as an important source of proteins. However, the presence of various bacteria can increase the risk of disease in humans. As a result, a crucial step in the processing of aquatic products is the disinfection of raw aquatic food. An intelligent ultraviolet c radiation (UVC) sterilization system was established and evaluated in this study. On the automated production line, the UVC lamp's sterilization intensity can be automatically adjusted to achieve intelligent sterilization of the various aquatic product categories. The system was implemented and evaluated for oyster surface sterilization experiments in the production line. The quality indicators of oysters, such as volatile salt nitrogen content and aerobic bacterial count, were measured before and after sterilization. The average sterilization rate of the intelligent system is 96.4%. The results showed that the system had an excellent sterilization effect and improved the shelf life of aquatic products.

Study on the sterilization effect of plasma jet and plasma activated water on Streptococcus mutans

To explore the effects of plasma jet (PJ) and plasma activated water (PAW) on the sterilization of Streptococcus mutans ( S. mutans) and compare the advantages and disadvantages of the two methods, so as to provide a basis for plasma treatment of dental caries and to enrich the treatment means of dental caries, an atmospheric pressure plasma excitation system was built, and the effects of PJ and PAW on the sterilization rate of S. mutans and the changes of temperature and pH during treatment were studied under different excitation voltage ( U e ) and different excitation time ( t e ). The results showed that in the PJ treatment, the difference in the survival rate of S. mutans between the treatment group and the control group was statistically significant ( P = 0.007, d=2.66) when U e = 7 kV and t e = 60 s, and complete sterilization was achieved at U e = 8 kV and t e = 120 s in the PJ treatment. In contrast, in the PAW treatment, the difference in the survival rate of S. mutans between the treatment group and the control group was statistically significant ( P = 0.029, d = 1.71) when U e = 7 kV and t e = 30 s, and complete sterilization was achieved with PAW treatment when U e = 9 kV and t e = 60 s. Results of the monitoring of temperature and pH showed that the maximum temperature rise during PJ and PAW treatment did not exceed 4.3 °C, while the pH value after PAW treatment would drop to a minimum of 3.02. In summary, the optimal sterilization parameters for PJ were U e =8 kV and 90 s < t e ≤ 120 s, while the optimal sterilization parameters for PAW were U e = 9 kV and 30 s< t e ≤ 60 s. Both treatment methods achieved non-thermal sterilization of S. mutans, where PJ required only a smaller U e to achieve complete sterilization, while at pH < 4.7, PAW only required a shorter t e to achieve complete sterilization, but its acidic environment could cause some chemical damage to the teeth. This study can provide some reference value for plasma treatment of dental caries.

Influence of Different Sterilization Methods on the Surface Chemistry and Electrochemical Behavior of Biomedical Alloys.

Sterilization is a prerequisite for biomedical devices before contacting the human body. It guarantees the lack of infection by eliminating microorganisms (i.e., bacteria, spores and fungi). It constitutes the last fabrication process of a biomedical device. The aim of this paper is to understand the effect of different sterilization methods (ethanol-EtOH, autoclave-AC, autoclave + ultraviolet radiation-ACUV and gamma irradiation-G) on the surface chemistry and electrochemical reactivity (with special attention on the kinetics of the oxygen reduction reaction) of CoCrMo and titanium biomedical alloys used as prosthetic materials. To do that, electrochemical measurements (open circuit potential, polarization resistance, cathodic potentiodynamic polarization and electrochemical impedance spectroscopy) and surface analyses (Auger Electron Spectroscopy) of the sterilized surfaces were carried out. The obtained results show that the effect of sterilization on the corrosion behavior of biomedical alloys is material-dependent: for CoCrMo alloys, autoclave treatment increases the thickness and the chromium content of the passive film increasing its corrosion resistance compared to simple sterilization in EtOH, while in titanium and its alloys, autoclave and UV-light accelerates its corrosion rate by accelerating the kinetics of oxygen reduction.

Influence of Heat Treatment on the Chemical, Physical, Microbiological and Sensorial Properties of Pork Liver Pâté as Affected by Fat Content.

The novelty of this study is the investigation of the effect of different heat treatments and, simultaneously, the effect of different fat levels on the quality of pork liver pâtés. Hence, this study aimed to evaluate the effect of heat treatment and fat content on selected properties of pork liver pâté. For this purpose, four batches of pâtés with two different fat contents (30 and 40% (w/w)) and two different heat treatments (pasteurisation: target temperature 70 °C, holding time of 10 min; sterilisation: target temperature 122 °C, holding time of 10 min) were manufactured. Chemical (pH, dry matter, crude protein, total lipid, ammonia, and thiobarbituric acid reactive substances (TBARS)), microbiological, colour, textural, rheological, and sensory analyses were performed. Both different heat treatment and fat content affected most of the parameters observed. Sterilisation ensured the commercial sterility of the manufactured pâtés, resulting in elevated TBARS values, hardness, cohesiveness, gumminess and springiness, and increased rheological parameters (G', G″, G*, and η*), as well as colour changes (decrease in L* and increase in a*, b*, and C* values) and deterioration of appearance, consistency, and flavour also being detected (p < 0.05). Higher fat content caused similar variations in the textural and viscoelastic properties, i.e., the increase in hardness, cohesiveness, gumminess and springiness, and also in G', G″, G*, and η* (p < 0.05). However, the colour and sensorial parameters changed in different ways compared to the changes induced by the sterilisation effect. Overall, the observed changes might not be desirable for some consumers and further research would be appropriate to improve especially the sensorial attributes of sterilised pork liver pâtés.

The Application of Ultraviolet Treatment to Prolong the Shelf Life of Chilled Beef.

This study simulated the storage conditions of chilled beef at retail or at home, and the sterilization and preservation effects of short-time ultraviolet irradiation were studied. The conditions of different irradiation distances (6 cm, 9 cm, and 12 cm) and irradiation times (6 s, 10 s, and 14 s) of ultraviolet (UV) sterilization in chilled beef were optimized, so as to maximally reduce the initial bacterial count, but not affect the quality of the chilled beef. Then, the preservation effect on the chilled beef after the optimized UV sterilization treatment during 0 ± 0.2 °C storage was investigated. The results showed that UV irradiation with parameters of 6 cm and 14 s formed the optimal UV sterilization conditions for the chilled beef, maximally reducing the number of microorganisms by 0.8 log CFU/g without affecting lipid oxidation or color change. The 6 cm and 14 s UV sterilization treatment of the chilled beef was able to reduce the initial microbial count, control the bacterial growth, and delay the increase in the TVB-N values during storage. Compared with the control group, the total bacterial count decreased by 0.56-1.51 log CFU/g and the TVB-N value decreased by 0.20-5.02 mg N/100 g in the UV-treated group. It was found that the TBARS value of the UV treatment group increased during late storage; on days 9-15 of storage, the TBARS values of the treatment group were 0.063-0.12 mg MDA/kg higher than those of the control group. However, UV treatment had no adverse impact on the pH, color, or sensory quality of chilled beef. These results prove that UV treatment can effectively reduce the microbial count on the surface of beef and improve its microbial safety, thus maintaining the quality of beef and prolonging its shelf life. This study could provide a theoretical basis for the preservation technology of chilled beef in small-space storage equipment.

Evaluation of plasma-activated water: Efficacy, stability, physicochemical properties, and mechanism of inactivation against Escherichia coli

In this study, plasma-activated water (PAW) was prepared by discharge below the surface of sterile distilled water. In addition to physicochemical properties, the bactericidal effect and mechanism of action of PAW were studied using Escherichia coli as the target microorganism. The plasma treatment would cause an increase in the redox potential (ORP), electrical conductivity (EC), NO3− and NO2− content, and a decrease in the pH of the water. At the same time, the sterilization effect of PAW on E. coli was progressively stronger with both discharge and immersion time, up to a maximum of 4.25 log CFU/mL. In addition, the EC, NO3− and NO2− content, as well as the bactericidal efficacy of PAW decreased with increasing storage time. The properties and bactericidal effects did not change significantly after PAW thawing (p > 0.05). Finally, proteomics techniques were used to identify and classify the differential proteins before and after PAW treatment. PAW treatment induced a stress response in E. coli. Differential expression proteins of biological processes including the metabolism of phosphorus-containing compounds and the cellular response to stimuli, as well as various binding-related and membrane structure-related, were induced.

Effect of sterilants and plant growth regulators in regenerating commonly used cassava cultivars at the Kenyan coast

Cassava is an important root crop whose seed system is undeveloped. Micropropagation of explants in vitro has the potential of addressing the challenge of the unavailability of healthy cassava planting materials. Therefore, the study determined the effect of sterilization and plant growth regulators on cassava explants to produce certified disease-free plants of commonly used cultivars at the coast of Kenya. The apical nodes drawn from the three cultivars of cassava, Tajirika and Kibandameno and Taita, were used as explants. The sterilant sodium hypochlorite (NaOCl) at 5, 10 and 15% and 70% ethanol for 1 and 5 min and sprayed for 20 s were tested for the effect on the explant. Similarly, the effect of BAP (6-Benzyl amino purine) and NAA (1-Naphthalene acetic acid) Plant Growth Regulators (PGRs) each at 0.5, 1 and 5 mg/L under optimal conditions of sterilization was determined. Surface sterilization using 10% NaOCl followed by spraying 70% ethanol for 20 s had 85% initiation on Tajirika whereas 5% NaOCl followed by spraying 70% ethanol for 20 s had 87% and 91% initiation in Kibandameno and Taita cultivars, respectively. In Tajirika, significantly (p < 0.05) high shooting of 68% was from 5 mg/L BAP in MS media whereas approximately 50% rooting was from either 0.5 mg/L BAP or 5 mg/L NAA in MS media. Kibandameno and Taita cultivars had approximately 50% shooting from MS media without PGRs. Kibandameno had >37% rooting from 0.5 to 5 mg/L BAP or NAA in MS media whereas Taita had approximately 50% rooting from 0 to 5 mg/L NAA in MS media. This protocol showed at least 50% success rate of initiation, shooting and rooting as a rapid multiplication regeneration of Tajirika and Kibandameno and Taita cultivar plantlets with little modification of humidity and temperatures in the growth chambers. This protocol requires validation for use in large-scale production of cassava plantlets to alleviate the inadequacy of cassava planting materials among farmers.

Rapid Pressure Hemostatic Drug Delivery and Microsystem Design Based on Battlefield Trauma

The battlefield rapid pressure hemostatic microsystem maximizes hemostasis efficiency. Battlefield wound has the characteristics of rapid blood loss and irregular surface, which needs to be treated in a very short time. The existing rapid hemostasis method has poor efficiency and no sterilization and disinfection effect. Therefore, we reported a wound pressure hemostatic microsystem based on gas generated by rapid chemical reaction. Before the device is used, the two chemicals in the device are isolated. During hemostasis, the flexible device is applied to the wound surface, and the two chemicals in the device are mixed and chemically reacted. And the large amount of gas generated by the reaction causes the balloon in the device to expand and exert lateral and longitudinal pressure on the surface of the wound, so that the wound quickly closed. At the same time, the drug storage unit in the device is under pressure to release the drug to the wound surface. In addition, the chemical reaction of the device has an endothermic effect, which can rapidly cool the wound surface. The lateral and longitudinal pressures of the flexible microsystem in the process of hemostasis were analyzed by numerical simulation. In the experiment, the maximum longitudinal pressure reached 270mmHg, meeting the requirements of surface wound hemostasis.

Effects of commercial sterilization on non-ginsenoside functional components in fresh ginseng pulps using widely targeted metabolomics

Commercial sterilization is a typical food processing method. The effects of commercial sterilization on non-ginsenoside functional components including phenolic acids, alkaloids, flavonoids, lignins and coumarins in ginsengs were studied by widely targeted metabolomics based on UPLC-ESI-MS/MS system. These components of ginsengs were significantly distinguished using principal component analysis. The results suggested that a total of 259 non-ginsenoside functional compounds were identified, among which 46 phenolic acids, 12 alkaloids, 18 flavonoids, 12 lignins and coumarins were increased. On the contrary, 7 phenolic acids, 4 alkaloids and 5 flavonoids were decreased. This study systematically analyzed the impact of commercial sterilization on the non-ginsenoside functional components in fresh ginseng pulp and provides novel reference values for ginseng processing.

Optimization of UV-C pulsed radiation strategy for a high-efficiency portable water sterilizer

In many places of the world, the lack of municipal facilities for water sanitation and purification makes self-treatment at a familiar scale, the only realistic solution to ensure continuous access to drinking water. In this context, UV disinfection treatment is a portable and efficient alternative to conventional methods, however, its power need is hindering its implementation in remote off-grid households. This work presents a portable water sterilizer device using UV-C LEDs, conceived for its direct implementation in isolated rural communities. Pulsed radiation operation has been studied as strategy to reduce the device energy demand. Most relevant parameters affecting the device operation and performance, namely voltage, radiation time, frequency and duty cycle; are thoroughly studied using the Design of Experiments methodology to optimize energy consumption and Escherichia coli removal from polluted water. The optimal conditions, found for pulsed radiation, showed a noteworthy reduction of 68 % of the energy consumption while improving the sterilization effectiveness, compared with continuous radiation. Furthermore, the efficiency of sterilization of the optimized prototype was benchmarked against a commercial device using river water samples. The presented prototype achieved higher E. coli disinfection effectiveness using a fraction of the energy consumption. All in all, the presented water sterilization device is an example of a technological improvement which uses energy efficiency as key developing driver while achieving performance requirements. Thus, contributing to the creation of affordable and efficient technological solutions to promote global access to drinking water.

Effect of Carrier Materials, Coinoculation and Sterilization on Survival of Plant Growth Promoting Microbes

The study was conducted to investigate diverse carrier materials out of agricultural and environmental waste, that plays a role in maintaining the shelf life of plant growth promoting microbes (PGPM) at room temperature for locally produced inoculants in Malawi. Five different formulations divided into sterilized and unsterilized were prepared, using different carrier materials namely; rice bran plus plant extract (RBP), biochar plus plant extract (BP), Filter mud plus plant extract (FMP), rice bran, biochar and plant extracts (RBCP), filter mud, biochar and plant extracts (FMBP). Carrier materials were packed in polyethylene pack (six per each treatment), thereafter each treatment was divided into sterilized and unsterilized. Each treatment was inoculated with either single or multiple inoculants. Survival of PGPM, was based on colony forming units (CFU) on specific selective media namely: modified yeast extract mannitol, pikovskaya’s, Alexandria and basal media for nitrogen fixing microbes, phosphate, potassium and zinc solubilising media respectively. Results revealed that encapsulated formulation of based combination formulation of RBCP in both single and multiple inoculants exerted high stable numbers of PGRM along the storage compared to other formulations. The results also show that unsterilized formulations exert high numbers compared to sterilized which is as a result of hydrogen peroxide accumulation during sterilization. The study reveals that filter mud based formulations currently used in both single and multiple inoculants is not favorable for local environments because microbial numbers decrease after 20 days at room temperature. This makes filter mud formulations usage not favorable for rural smallholder farmers with no refrigeration facilities.

PH-Responsive Nanogel for Photothemal-Enhanced Chemodynamic Antibacterial Therapy

Chemodynamic therapy (CDT) and photothermal therapy (PTT) have been widely studied as treatment alternatives to anbiotics to avoid the occurrence of bacterial resistance because of their negligible bacterial resistance and high antibacterial efficiencies. Herein, we developed an infection microenvironment-responsive nanogel (STF) to successfully achieve a PTT synergized CDT for bacterial infection. Through a one-step/pot method, STF nanotherapeutics consisting of Fe3+/sodium alginate (SA) based nanogels and Fe3+/tannic acid (TA) based metal–phenolic networks (MPNs) were conveniently prepared by the coordination-triggered simultaneous self-assembly of SA, TA, and Fe3+ ions. Afterward, their photothermal and catalytic performances were intensively investigated. Moreover, the sterilization effect of the STF nanogel was evaluated through in vitro and in vivo bactericidal assays. The STF nanogel exhibited a photothermal enhanced peroxidase-like activity because of the good photothermal effect of MPNs. In addition, its Fenton activity was further accelerated by an extra amount of Fe2+ derived from the degradation of Fe3+-chelating agents (SA) and reduction of TA. Together, the STF nanogel possessed a photothermal/Fe2+ dual-augmented catalytic property. In vitro and in vivo antibacterial assays proved its satisfactory bactericidal efficiency owing to PTT/Fe2+ dual-enhanced CDT. Our research findings suggested that the developed intelligent bactericidal nanogel has great potential to be used as an antibiotic alternative to avoid bacterial resistance in future clinical treatments.

Does Sterilization Affect the Performance of Single-Step Resin Composite Polishers?

(1) Background: Single-step polishers are used extensively for resin-composite polishing. The purpose of this study was to evaluate the effect of sterilization on their performance. (2) Methods: Optrapol Next Generation/Ivoclar-Vivadent, Jazz Supreme/SS White, Optishine Brush/Kerr and Jiffy Polishing Brush/Ultradent were used for polishing a nanohybrid resin composite (IPS Empress Direct/Ivoclar-Vivadent). Polishers (n = 40) were microscopically inspected before use. After polishing, surface roughness (Sa, Sz, Sdr, Sci) and gloss were determined. Polishers were subsequently sterilized and microscopically re-examined. The process was repeated four times on new samples (n = 200). Data were analyzed using the Friedman test and Wilcoxon post hoc test, at α = 0.05. (3) Results: Optrapol's performance improved after the first sterilization for Sa and gloss, whereas it declined after the fourth sterilization for Sa. Jazz's, improved after the second sterilization for Sa and gloss and after the third sterilization for Sdr. An improvement trend was observed for Optishine after the first sterilization, but not statistically significant. Sa, Sz, and gloss declined after the fourth sterilization. Jiffy's performance was inconsistent, with a trend of performance loss after the fourth sterilization. (4) Conclusions: Performance of all polishing systems improved after the initial sterilization, but deteriorated after the fourth sterilization cycle. However, their performance can be considered clinically acceptable for a longer period of use.

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.