Recent advances in sterilization and disinfection technology: A review

Review of research advances in microbial sterilization technologies and applications in the built environment

As globalization accelerates, microbial contamination in the built environment poses a major public health challenge. Especially since Corona Virus Disease 2019 (COVID-19), microbial sterilization technology has become a crucial research area for indoor air pollution control in order to create a hygienic and safe built environment. Based on this, the study reviews sterilization technologies in the built environment, focusing on the principles, efficiency and applicability, revealing advantages and limitations, and summarizing current research advances. Despite the efficacy of single sterilization technologies in specific environments, the corresponding side effects still exist. Thus, this review highlights the efficiency of hybrid sterilization technologies, providing an in-depth understanding of the practical application in the built environment. Also, it presents an outlook on the future direction of sterilization technology, including the development of new methods that are more efficient, energy-saving, and targeted to better address microbial contamination in the complex and changing built environment. Overall, this study provides a clear guide for selecting technologies to handle microbial contamination in different building environments in the future, as well as a scientific basis for developing more effective air quality control strategies.

Development of breast tissue-mimicking electrical and acoustic phantoms for magneto-acoustic electrical tomography

Magneto-acousto electrical tomography (MAET) is a novel medical imaging technique that relies on the difference in electrical properties between healthy and tumor tissues. To facilitate MAET experiments, this study proposes a comprehensive procedure for developing, characterizing, and preserving realistic breast tissue-mimicking phantoms. We developed nontoxic and inexpensive phantoms using sodium alginate, graphite powder, agar, propanediol, aluminum powder, glycine, and deionized water. The dielectric (conductivity and permittivity) and acoustic (speed of sound) properties of phantoms (breast fat, breast gland, and tumor) within the 1-8 MHz frequency range were measured to ensure their suitability for MAET experiments. In conclusion, this study presents a detailed methodology for the preparation, characterization, and preservation of realistic breast tissue-mimicking phantoms tailored for MAET experiments.

Role of advanced cleaning and sanitation techniques in biofilm prevention on dairy equipment

Biofilm formation on dairy equipment is a persistent challenge in the dairy industry, contributing to product contamination, equipment inefficiency, and economic losses. Traditional methods such as manual cleaning and basic chemical sanitation are discussed as foundational approaches, followed by an in-depth investigation of cutting-edge technologies, including clean-in-place systems, high-pressure cleaning, foam cleaning, ultrasonic and electrochemical cleaning, dry ice blasting, robotics, nanotechnology-based agents, enzymatic cleaners, and oxidizing agents. Enhanced sanitation techniques, such as dry steam, pulsed light, acidic and alkaline electrolyzed water, hydrogen peroxide vapor, microbubble technology, and biodegradable biocides, are highlighted for their potential to achieve superior sanitation while promoting sustainability. The effectiveness, feasibility, and limitations of these methods are evaluated, emphasizing their role in maintaining dairy equipment hygiene and reducing biofilm-associated risks. Additionally, challenges, such as equipment compatibility, cost, and regulatory compliance, are addressed, along with insights into future directions and innovations, including automation, smart cleaning systems, and green cleaning solutions. This review provides a comprehensive resource for researchers, industry professionals, and policymakers aiming to tackle biofilm formation in dairy production systems and enhance food safety, operational efficiency, and sustainability.

Efficacy of ultraviolet-light emitting diodes in bacterial inactivation and DNA damage via sensitivity evaluation using multiple wavelengths and bacterial strains

Ultraviolet-light emitting diodes (UV-LEDs) have garnered attention for their efficient bacterial inactivation. However, in previous studies, it has been difficult to strictly compare the bacterial inactivation effect of UV irradiation among wavelengths differing by a few nanometers because detailed UV irradiation conditions for comparison, such as the LED characteristics at each wavelength and power supply characteristics, have not been established. Therefore, this study aimed to evaluate UV inactivation of 10 bacterial strains across 13 wavelengths (250-365 nm) using a standardized irradiation system previously reported to identify the most effective wavelengths for prevention of bacterial infection and contamination. Bacterial inactivation dose response curves were generated to determine the fluence required to archive 1-3 log10 inactivation. The results indicated that Gram-negative bacteria exhibited higher initial sensitivity compared with Gram-positive bacteria. Wavelength-dependent inactivation peaked at 263-270 nm, correlating strongly with cyclobutane pyrimidine dimer production (r > 0.9 for most strains). Deconvolution analysis confirmed that bacterial inhibition was maximal around 267.6 nm. Furthermore, UV-LEDs outperformed low-pressure mercury lamps in terms of bacterial inactivation under equivalent fluences, attributed to differences in spectral emission profiles. These findings will help optimize UV-LED sterilization methods for broader applications in microbial control.

Antibacterial collagen-guar gum hydrogels with zeolitic imidazolate framework-67 (ZIF-67): an innovative platform for advanced wound healing

The current challenge in developing wound healing dressings lies in achieving antibacterial effects while avoiding cytotoxicity to cells that are crucial for the healing process. Addressing this challenge, Zeolitic Imidazolate Framework-67 (ZIF-67), a cobalt-containing metal-organic framework (MOF), has emerged as a promising additive due to cobalt's broad-spectrum antimicrobial effects. This study developed semi-interpenetrating polymer network (semi-IPN) hydrogels by incorporating 1-3 wt.% ZIF-67 into collagen-guar gum matrices, resulting in biocomposites with tunable structural and functional properties. These biocomposites exhibit a fibrillar-granular morphology, uniform cobalt ion distribution on a semi-crystalline surface, and strong antibacterial activity against Escherichia coli (E. coli). At 3 wt.%, ZIF-67 accelerates gelation, strengthens crosslinking interactions, and enhances the storage modulus, thermal stability, and hydrolytic resistance of the hydrogels. Furthermore, biocomposites with 1 wt.% ZIF-67 also function as in-situ curcumin delivery systems, offering controlled release under physiological conditions and significant biodegradation in the presence of collagenase. In vitro tests demonstrate that the chemical composition of these hydrogels, regardless of ZIF-67 content, effectively supports monocyte and fibroblast metabolic activity, promotes cell proliferation, and increases interleukin-10 (IL-10) secretion by human monocytes. Additionally, the absence of hemolytic effects in human blood further underscores the safety and suitability of these hydrogel biocomposites for advanced wound treatment applications.

Electronic Switching between Hot Electrons and Hot Holes via Schottky Junctions during Chemical Reactions

Hot carriers, generated through nonadiabatic energy dissipation during exothermic catalytic reactions, play a pivotal role in enhancing catalytic performance. Upon generation, hot electrons typically reside in the sp-band above the Fermi level, while hot holes are formed in the d-band below the Fermi level, following the energy distribution of the metal's electronic structure. However, it has been technically challenging to simultaneously capture and understand the flow of these two opposite charges during chemical reactions. In this study, we employed Pt/Si Schottky nanodiodes to detect reaction-induced hot carriers. The flux of hot electrons and hot holes was observed to vary depending on whether the Pt catalyst was deposited on n-Si or p-Si, respectively. Indeed, the detection probability of hot holes was lower compared to hot electrons, attributed to the shorter mean free path of hot holes. This demonstrates that for quantitative capture of hot carriers at the metal-semiconductor Schottky junction, the transport process through which the excited carrier passes the metal must also be considered. When a forward bias was applied to the Pt/p-Si nanodiode, a switch from hot hole to hot electron transfer was observed, due to the perturbation of the band structures. Our first prototype platforms, which self-control the transfer of hot carriers during the chemical reaction using Schottky junctions, may offer insights into potential applications of hot carriers in catalytic devices, energy conversion-based devices, or chemical sensors.

Inactivation of multidrug-resistant bacteria using cold atmospheric-pressure plasma technology

Objective

This study aimed to investigate the impact of cold atmospheric-pressure plasma (CAP) on multidrug-resistant (MDR) bacteria on various surfaces under nosocomial circumstances and the underlying mechanism.

Method

Four common MDR bacteria (carbapenem-resistant Acinetobacter baumannii, carbapenem-resistant Pseudomonas aeruginosa, methicillin-resistant Staphylococcus aureus, and carbapenem-resistant Klebsiella pneumoniae) were inoculated on nosocomial surfaces, which were subsequently exposed to CAP. Then the bacteria from surfaces were recovered and diluted. The killing curve was analyzed to evaluate the sterilization effects of CAP. Electron microscopy was used to evaluate the changes in cell morphology.

Result

In the CAP-producing device, most of the MDR bacteria were nearly inactivated after 2 h of CAP treatment. Under the simulated ward, CAP exerted an inactivating effect on MDR bacteria. Scanning electron microscopy revealed that the surface of MDR bacteria became blurred, the bodies ruptured and adhered to each other after CAP treatment. The cell walls were thinner as revealed by transmission electron microscopy.

Conclusion

CAP could inactivate the most common MDR bacteria on nosocomial surfaces in simulation ward settings by destroying the structure of pathogens. Our data provided insights into the sterilization of MDR bacteria using CAP and suggested a novel in-hospital disinfection alternative.

Non-thermal plasma decontamination of microbes: a state of the art

Microbial decontamination is a critical concern in various sectors, from healthcare to food processing. Traditional decontamination methods, while effective to a degree, present limitations in terms of environmental impact, efficiency, and potential harm to the target material. This review investigates the emerging realm of non-thermal plasma (NTP) as a promising alternative for microbial decontamination, emphasizing its mechanisms, reactor designs and applications. The mechanism decomposed into physical, chemical and biological effects of plasma, are elaborated upon to provide a foundational understanding of the intrinsic principles of plasma decontamination. Except for the generation type of NTP, reactors and other parameters by which NTP achieves microbial decontamination, emphasizing the design considerations and parameters that influence its efficacy. Moreover, the latest applications of NTP in decontaminating air, water, and surfaces, supported by the latest research findings in each domain are explored. Additionally, the perspectives on the future research tendencies of NTP decontamination and disinfection are highlighted with potential avenues for exploration and innovation. Through this comprehensive review, the aim is to underscore the potential of NTP, particularly DBD plasma, as a versatile, efficient, and environmentally friendly method for microbial decontamination.

Microbial inactivation and emission of volatile organic compounds in low-heat thermal treatment of infectious healthcare waste

The growing use of low-temperature waste decontamination devices in hospitals has raised concerns about their inactivation efficiencies and emissions of volatile organic compounds (VOCs). This study evaluated the decontamination efficiencies, as well as VOC and ammonia emissions, of sterilizer devices in four hospitals, including two autoclaves (one with a shredder and one without), a hydroclave, and a dry heating device. Decontamination efficiency was assessed using mechanical and biological indicators, while air pollutants, including VOCs and ammonia, were measured according to National Institute for Occupational Safety and Health (NIOSH) methods. Evaluation of decontamination revealed that the autoclave with a shredder achieved the highest efficiency (up to 100 %), highlighting the importance of shredding, while the autoclave without a shredder demonstrated the lowest performance. Maintaining an appropriate temperature was also identified as a reliable indicator of device efficiency. The hydroclave exhibited the highest VOC and ammonia emissions (128.03 mg/m³ for VOCs and 6.48 mg/m³ for ammonia), while the autoclaves had the lowest ones (45.72 mg/m³ for VOCs and 2.58 mg/m³ for ammonia). The three major VOCs emitted from the sterilizer devices included dichloromethane, ethyl alcohol, and ethyl acetate (with a total level of 22.82 mg/m³). VOC and ammonia emissions were affected by device operational factors and waste composition. These findings highlighted the critical need to optimize hospital waste management practices. Adhering to operational parameters that directly influence device efficiency, along with equipping low-temperature sterilization devices with air pollutant control systems, can significantly minimize emissions, thereby reducing occupational health risks and environmental impacts.

Extended-spectrum β-lactamase-producing bacteria from hospital wastewater pipes: isolation, characterization and biofilm control using common disinfectants

BACKGROUND

Hospital wastewater systems have been identified as reservoirs for antibiotic-resistant bacteria, with biofilms harbouring extended-spectrum β-lactamase (ESBL)-producing micro-organisms posing significant infection risk.

AIM

To study the antimicrobial susceptibility and biofilm control of ESBL-producing bacteria from wastewater pipes from a tertiary care teaching hospital in Ireland, which had experienced endemic infection outbreaks caused by ESBL-producing bacteria.

METHODS

Following isolation of ESBL producers on selective agar, antibiotic susceptibility profiles were determined for a number of antibiotics assessed for their ability to form biofilms. Biofilm eradication studies using the commercially available disinfectants bleach, Optizan™, Virkon™ and Clinell™ were performed on selected isolates.

FINDINGS

ESBL-producing bacteria (N = 39 isolates) showed a high degree of resistance to β-lactams. Biofilm-forming ability ranged from non-adherent to strongly adherent and appeared to be source dependent, suggesting that the characteristics of the pipe environment played an important role in biofilm formation. All disinfectants showed effective biofilm eradication under suggested working conditions. Effectiveness was significantly reduced following reductions in concentration and contact time, with only Clinell™ showing significant biofilm reduction against all isolates at all concentrations and contact times tested. Of the chlorine-based formulations, Optizan™ frequently outperformed bleach at lower concentrations and treatment times. Biofilm eradication was strain dependent, with varying disinfectant response profiles observed from biofilms from different Stenotrophomonas maltophilia isolates.

CONCLUSIONS

This study highlights the high degree of ESBL-producing bacteria recovery from patient-facing hospital wastewater apparatus. Their ability to form resident biofilms and act as potential reservoirs of infection emphasizes the need for rigorous and effective infection control practices.

Influence of Material, Sterilization, and Disinfection on the Accuracy of Three-Dimensional Printed Surgical Templates: An In Vitro Study

OBJECTIVES

To evaluate the influence of the three-dimensional (3D) printing technology, material, sterilization, and disinfection on the accuracy of guided surgical templates.

MATERIAL AND METHODS

Fifty printed resin surgical templates were designed and fabricated using a digital light processing 3D printer with a photopolymerizing resin, and 50 printed metal surgical templates were designed and fabricated using a selective laser melting 3D printer with a titanium alloy. Templates from both groups were randomly divided into five subgroups involving different sterilization and disinfection procedures. The group without any sterilization or disinfection procedure served as the control group, whereas the other groups were used as the study groups (hydrogen peroxide gas plasma sterilization, 5% povidone-iodine disinfection, 75% ethyl alcohol disinfection, and steam autoclave sterilization). Implant simulations were performed on the 3D-printed resin models, and postoperative impressions were acquired with scan bodies attached to the implants. All surgical templates were digitally scanned. The root mean square was used to determine and quantify fabrication accuracy and reproducibility, and the definitive and planned implant positions were compared.

RESULTS

The printed resin templates exhibited lower fabrication accuracy and reproducibility, as well as higher 3D deviations, after steam autoclave sterilization (p < 0.001); however, the printed metal templates were not affected by the different sterilization or disinfection procedures (p > 0.05).

CONCLUSIONS

Printed metal surgical templates are viable alternatives for guided implant surgery. Preoperative steam or gas plasma sterilization is recommended, especially for metal templates, as resin templates show deformation and decreased accuracy after steam sterilization.

TRIAL REGISTRATION

chictr.org.cn number: ChiCTR2400081334.

Versatile platforms of mussel-inspired agarose scaffold for cell cultured meat

INTRODUCTION

Biomaterial scaffolds are critical for cell cultured meat production. polysaccharide scaffolds lack essential animal cell adhesion receptors, leading to significant challenges in cell proliferation and myogenic differentiation. Thus, enhancing cell adhesion and growth on polysaccharide scaffolds is strongly required to supply the gaps in cell-cultured meat production.

OBJECTIVES

This study aims to develop a multifunctional cell-responsive hydrogel scaffold for the in vitro production of myofibers and structured cell cultured meat through a "cell adhesion-proliferation-differentiation" strategy.

METHODS

A polydopamine coating was applied to agarose hydrogel scaffolds using a dipping technique. The capability of scaffolds for myofiber preparation was assessed by evaluating cell adhesion, proliferation, and myogenic differentiation. Utilizing isolated porcine skeletal muscle satellite cells (PSMSCs), the feasibility of structured cell cultured pork tissue supported by agarose hydrogel film scaffolds was further investigated through three-dimensional imaging and scanning electron microscopy analysis. The physicochemical properties of the structured cell cultured pork tissue were evaluated through staining and texture analysis.

RESULTS

The incorporation of a polydopamine coating facilitated a remarkable 100 % cell adhesion rate on agarose hydrogel scaffolds, which also demonstrated reusability. The agarose hydrogel scaffolds retained adequate mechanical properties, enabling the adhered cells to proliferate effectively and differentiate into myofiber. Moreover, isolated PSMSCs maintained growth potential on the agarose hydrogel scaffolds, thereby imparting the scaffolds with the ability to generate substantial quantities of multinucleated myofibers. Furthermore, we established a structured cell culture pork meat model, characterized by high-density myofibers and agarose hydrogel film scaffolds, which exhibited the texture and color typical of real pork.

CONCLUSION

The innovative agarose/polydopamine scaffold functions as a multifunctional platform for cell culture, offering novel avenues for the diversification and scalable production of cultured meat, and promising significant reductions in production costs for cell cultured meat.

Protective Effects of Carvacrol on Mercuric Chloride-Induced Lung Toxicity Through Modulating Oxidative Stress, Apoptosis, Inflammation, and Autophagy

Mercuric chloride (HgCl2) is extremely toxic to both humans and animals. It could be absorbed via ingestion, inhalation, and skin contact. Exposure to HgCl2 can cause severe health effects, including damages to the gastrointestinal, respiratory, and central nervous systems. The purpose of this work was to explore if carvacrol (CRV) could protect rats lungs from damage caused by HgCl2. Intraperitoneal injections of HgCl2 at a dose of 1.23 mg/kg body weight were given either alone or in conjunction with oral CRV administration at doses of 25 and 50 mg/kg body weight for 7 days. The study included biochemical and histological techniques to examine the lung tissue's oxidative stress, apoptosis, inflammation, and autophagy processes. HgCl2-induced reductions in GSH levels and antioxidant enzymes (SOD, CAT, and GPx) activity were enhanced by CRV co-administration. Furthermore, MDA levels were lowered by CRV. The inflammatory mediators NF-κB, IκB, NLRP3, TNF-α, IL-1β, IL6, COX-2, and iNOS were all reduced by CRV. When exposed to HgCl2, the levels of apoptotic Bax, caspase-3, Apaf1, p53, caspase-6, and caspase-9 increased, but the levels of antiapoptotic Bcl-2 reduced after CRV treatment. CRV decreased levels of Beclin-1, LC3A, and LC3B, which in turn decreased HgCl2-induced autophagy damage. After HgCl2 treatment, higher pathological damage was observed in terms of alveolar septal thickening, congestion, edema, and inflammatory cell infiltration compared to the control group while CRV ameliorated these effects. Consequently, by preventing HgCl2-induced increases in oxidative stress and the corresponding inflammation, autophagy, apoptosis, and disturbance of tissue integrity in lung tissues, CRV might be seen as a useful therapeutic alternative.

Characterization and Safety Evaluation of Autoclaved Gut Commensal Parabacteroides goldsteinii RV-01

Gut commensals play important roles in maintaining the homeostasis of human health. Previous studies indicated that the abundance of P. goldsteinii in animal hosts was increased by the administration of prebiotics such as polysaccharides purified from iconic oriental medicinal fungi. Subsequently, P. goldsteinii was found to exert beneficial effects on the amelioration of multiple chronic inflammation-associated diseases. Even so, during the process of the development of P. goldsteinii as a next-generation probiotic (NGP), care has to be taken when it is used as a functional food ingredient. In this study, we isolated a novel P. goldsteinii strain, RV-01, from the feces of a healthy adult and carried out comprehensive analyses of its genomic and phenotypic characteristics. Bioinformatic analysis of P. goldsteinii RV-01 revealed the absence of potential virulence genes, as well as the presence of genes and traits potentially beneficial to human health, such as the production of short-chain fatty acids, anti-inflammatory lipopolysaccharides, and zwitterionic capsular polysaccharides, as well as immune regulatory proteins. To circumvent any potential side effects, the P. goldsteinii RV-01 was autoclaved before proceeding to the nonclinical safety assessment. The autoclaved P. goldsteinii RV-01 retained its anti-inflammatory effect in human colon epithelial cells. In addition to the three genotoxicity assays, 28-day subacute and 90-day subchronic animal toxicity studies (the highest dose tested was equivalent to 8.109 × 1010P. goldsteinii RV-01 cells/kg body weight/day) were also implemented. The results of all studies were negative for toxicity. These results support the conclusion that autoclaved P. goldsteinii RV-01 is safe for use as a food ingredient.

Assessment of Ultraviolet-C Light for Sterilization of Hysteroscopy Instruments

Objective To evaluate the sterilization efficacy of hysteroscopy instruments using ultraviolet C (UV-C) light at a wavelength of 259 nm in the Endoscopic Diagnostic Center of the National Institute of Perinatology. Methods Consecutive patients undergoing office hysteroscopy via the Bettochi vaginoscopy technique were included, excluding those with conditions such as viable intrauterine pregnancy or acute pelvic infection. Samples were collected from six designated sites of the hysteroscope, including the inner sheath, internal holes of the inner sheath, lens, graspers, scissors, and outer sheath. Initially, samples were taken after the first sterilization using a LAOKEN LK/MJG-150 Plasma Sterilizer (Chengdu, China). Next, samples were collected after the routine use of the hysteroscope in the office setting to confirm contamination. Subsequently, a new set of samples were taken after a 20-minute UV-C sterilization cycle with the EsteriUV device. Results The initial sterilization achieved a 96.73% sterilization rate, with ten samples testing positive for Staphylococcus coagulase-negative. Post-hysteroscopy, contamination increased significantly. Afterward, UV-C sterilization achieved a 96.08% sterilization rate, with 11 samples positive for Staphylococcus coagulase-negative and one for Streptococcus anginosus (p=0.66). No clinical infections were reported in any patient within one-month post-procedure. Conclusion UV-C light is a viable alternative for hysteroscopy instrument sterilization, demonstrating comparable efficacy to conventional methods. Further studies are recommended to optimize UV-C parameters for enhanced sterilization efficiency.

The potential role of violet-blue light to preventing hospital acquired infections: a systematic review

Healthcare-associated infections (HAIs) are a major challenge in modern healthcare, leading to increased mortality, financial burden and negative societal impact. The World Health Organization (WHO) and others have highlighted the alarming rise in HAIs, exacerbated by antimicrobial resistance (AMR), which further complicates treatment. The efficacy of violet-blue light (VBL) technology (approximately 405–420 nm) in inactivating various pathogens and its safety for human exposure have been extensively studied. This study analyses the scientific literature on the use of VBL as a disinfection method in health care settings, with cost and safety implications. It discusses VBL in comparison to other disinfection methods, the implications of its use, and its potential in reducing HAIs due to its ability to be used in occupied environments. While UV technology is more effective at bacterial inactivation, the continuous application of VBL compensates for this difference. UV and VBL technologies have a positive environmental impact, eliminating the need for consumables and reducing waste. Safety concerns are very limited for VBL compared to UV when properly used. The literature highlights that implementing VBL can be a significant step in continuous environmental disinfection in both healthcare and domestic settings. VBL is safe for occupants and offers a feasible, green method for combating environmental contamination and potentially reducing HAIs.

Cold atmospheric plasma (CAP): a revolutionary approach in dermatology and skincare

Cold atmospheric plasma (CAP) technology has emerged as a revolutionary therapeutic technology in dermatology, recognized for its safety, effectiveness, and minimal side effects. CAP demonstrates substantial antimicrobial properties against bacteria, viruses, and fungi, promotes tissue proliferation and wound healing, and inhibits the growth and migration of tumor cells. This paper explores the versatile applications of CAP in dermatology, skin health, and skincare. It provides an in-depth analysis of plasma technology, medical plasma applications, and CAP. The review covers the classification of CAP, its direct and indirect applications, and the penetration and mechanisms of action of its active components in the skin. Briefly introduce CAP's suppressive effects on microbial infections, detailing its impact on infectious skin diseases and its specific effects on bacteria, fungi, viruses, and parasites. It also highlights CAP's role in promoting tissue proliferation and wound healing and its effectiveness in treating inflammatory skin diseases such as psoriasis, atopic dermatitis, and vitiligo. Additionally, the review examines CAP's potential in suppressing tumor cell proliferation and migration and its applications in cosmetic and skincare treatments. The therapeutic potential of CAP in treating immune-mediated skin diseases is also discussed. CAP presents significant promise as a dermatological treatment, offering a safe and effective approach for various skin conditions. Its ability to operate at room temperature and its broad spectrum of applications make it a valuable tool in dermatology. Finally, introduce further research is required to fully elucidate its mechanisms, optimize its use, and expand its clinical applications.

Electromagnetic wave-based technology for ready-to-eat foods preservation: a review of applications, challenges and prospects

In recent years, the ready-to-eat foods market has grown significantly due to its high nutritional value and convenience. However, these foods are also at risk of microbial contamination, which poses food safety hazards. Additionally, traditional high-temperature sterilization methods can cause food safety and nutritional health problems such as protein denaturation and lipid oxidation. Therefore, exploring and developing effective sterilization technologies is imperative to ensure food safety and nutritional properties, and protect consumers from potential foodborne diseases. This paper focuses on electromagnetic wave-based pasteurization technologies, including thermal processing technologies such as microwave, radio frequency, and infrared, as well as non-thermal processing technologies like ultraviolet, irradiation, pulsed light, and photodynamic inactivation. Furthermore, it also reviews the antibacterial mechanisms, advantages, disadvantages, and recent applications of these technologies in ready-to-eat foods, and summarizes their limitations and prospects. By comparing the limitations of traditional high-temperature sterilization methods, this paper highlights the significant advantages of these pasteurization techniques in effectively inhibiting microbial growth, slowing lipid oxidation, and preserving food nutrition and flavor. This review may contribute to the industrial application and process optimization of these pasteurization technologies, providing an optimal choice for preserving various types of ready-to-eat foods.

New commercial wipes inhibit the dispersion and adhesion of Staphylococcus aureus and Pseudomonas aeruginosa biofilms

AIM

Bacterial biofilms can form on surfaces in hospitals, clinics, farms, and food processing plants, representing a possible source of infections and cross-contamination. This study investigates the effectiveness of new commercial wipes against Staphylococcus aureus and Pseudomonas aeruginosa biofilms (early attachment and formed biofilms), assessing LH SALVIETTE wipes (Lombarda H S.r.l.) potential for controlling biofilm formation.

METHODS AND RESULTS

The wipes efficacy was studied against the early attachment phase and formed biofilm of S. aureus ATCC 6538 and P. aeruginosa ATCC 15442 on a polyvinyl chloride (PVC) surface, following a modified standard test EN 16615:2015, measuring Log10 reduction and cell viability using live/dead staining. It was also evaluated the wipes anti-adhesive activity over time (3 h, 2 4h), calculating CFU.mL-1 reduction. Data were analyzed using t-student test. The wipes significantly reduced both early phase and formed S. aureus biofilm, preventing dispersion on PVC surfaces. Live/dead imaging showed bacterial cluster disaggregation and killing action. The bacterial adhesive capability decreased after short-time treatment (3 h) with the wipes compared to 24 h.

CONCLUSIONS

Results demonstrated decreased bacterial count on PVC surface both for early attachment phase and formed biofilms, also preventing the bacterial biofilm dispersion.

Molybdenum disulfide nanosheets based non-oxygen-dependent and heat-initiated free radical nanogenerator with antimicrobial peptides for antimicrobial, biofilm ablation and wound healing

Chronic refractory wounds caused by multidrug-resistant (MDR) bacterial and biofilm infections are a substantial threat to human health, which presents a persistent challenge in managing clinical wound care. We here synthesized a composite nanosheet AIPH/AMP/MoS2, which can potentially be used for combined therapy because of the photothermal effect induced by MoS2, its ability to deliver antimicrobial peptides, and its ability to generate alkyl free radicals independent of oxygen. The synthesized nanosheets exhibited 61 % near-infrared (NIR) photothermal conversion efficiency, marked photothermal stability and free radical generating ability. The minimal inhibitory concentrations (MICs) of the composite nanosheets against MDR Escherichia coli (MDR E. coli) and MDR Staphylococcus aureus (MDR S. aureus) were approximately 38 μg/mL and 30 μg/mL, respectively. The composite nanosheets (150 μg/mL) effectively ablated >85 % of the bacterial biofilm under 808-nm NIR irradiation for 6 min. In the wound model experiment, approximately 90 % of the wound healed after the 4-day treatment with the composite nanosheets. The hemolysis experiment, mouse embryonic fibroblast (MEFs) cytotoxicity experiment, and mouse wound healing experiment all unveiled the excellent biocompatibility of the composite nanosheets. According to the transcriptome analysis, the composite nanosheets primarily exerted a synergistic therapeutic effect by disrupting the cellular membrane function of S. aureus and inhibiting quorum sensing mediated by the two-component system. Thus, the synthesized composite nanosheets exhibit remarkable antibacterial and biofilm ablation properties and therefore can be used to improve wound healing in chronic biofilm infections.

Sandwich-structured continuous ZIF-8/Ti3C2 MXene/ZIF-8 for efficient sterilization: Enhanced photocatalytic activity, photothermal effect, and environmental safety

The development of effective water purification systems is crucial for controlling and remediating environmental pollution, especially in terms of sterilization. Herein, we demonstrate elaborately designed composite nanosheets with a sandwich structure, composed of two-dimensional (2D) Ti3C2 MXene nanosheet core and conformal ZIF-8 ultrathin outer layers, and their potential applications in photocatalytic sterilization. The study results indicate that the conformal ZIF-8-MXene nanosheet exhibits an expanded light absorption range (826 nm), improved photothermal conversion efficiency (6.2 °C s-1), and photocurrent response, thus boosting photocatalytic sterilization efficiency (6.63 log10 CFU mL-1) against Escherichia coli under simulated sunlight within 90 min. Interestingly, 2D ZIF-8 layers exhibit positive zeta potential (19 mV), good hydrophilicity (40.6°), and local photogenerated-hole accumulation, possessing efficient bacteria-trapping efficiency. Membrane filters fabricated from optimized composite nanosheets exhibit an outstanding bacteria-trapping and sterilization efficiency (almost 100 %) against Escherichia coli under simulated sunlight within 30 min of the flow photocatalytic experiments. This work not only presents a rational structural design of the conformal and ultrathin anchoring of ZIF-8 onto a 2D conductive material for bacteria-trapping and sterilization, but also opens new opportunities for using metal-organic frameworks in photocatalytic disinfection of drinking water.

Antimicrobial Photodynamic Therapy: Self-Disinfecting Surfaces for Controlling Microbial Infections

Microbial infections caused by bacteria, viruses, and fungi pose significant global health threats in diverse environments. While conventional disinfection methods are effective, their reliance on frequent chemical applications raises concerns about resistance and environmental impact. Photodynamic self-disinfecting surfaces have emerged as a promising alternative. These surfaces incorporate photosensitizers that, when exposed to light, produce reactive oxygen species to target and eliminate microbial pathogens. This review explores the concept and mechanism of photodynamic self-disinfecting surfaces, highlighting the variety and characteristics of photosensitizers integrated into surfaces and the range of light sources used across different applications. It also highlights the effectiveness of these surfaces against a broad spectrum of pathogens, including bacteria, viruses, and fungi, while also discussing their potential for providing continuous antimicrobial protection without frequent reapplication. Additionally, the review addresses both the advantages and limitations associated with photodynamic self-disinfecting surfaces and concludes with future perspectives on advancing this technology to meet ongoing challenges in infection control.

Acid etching post-treatment enhanced fungal sterilization performance of copper-manganese-cerium oxide in liquid and aerosol: Materials and molecular biological mechanisms

Bioaerosol is one of the main ways to spread respiratory infectious diseases. In order to further improve the sterilization efficiency of copper-manganese-cerium oxide (CuMnCeOx), the post-treatment method based on acid etching was adopted. The results showed that sterilization efficiency of the treated CuMnCeOx could reach 99% in aerosol with space velocity of 1400 h-1. L(+)-ascorbic acid successfully promoted the formation of Cu+, oxygen vacancies and the generation of reactive oxygen species (ROS) on the surface of the treated CuMnCeOx. During sterilization in liquid system, the transcriptome identified 316 differentially expressed genes, including 270 up-regulated genes and 46 down-regulated genes. Differentially expressed genes were significantly enriched in cell wall (GO:0005618) and external encapsulating structure (GO:0030312). Up-regulated genes were shown in regulation of reactive oxygen species biosynthetic processes (GO:1903409, GO:1903426, GO:1903428) and positive regulation all of reactive oxygen species metabolic process (GO:2000379), indicating that ROS induced cell death by destroying cell wall.

Unraveling the nuclear isotope tapestry: Applications, challenges, and future horizons in a dynamic landscape

Nuclear isotopes, distinct atoms characterized by varying neutron counts, have profoundly influenced a myriad of sectors, spanning from medical diagnostics and therapeutic interventions to energy production and defense strategies. Their multifaceted applications have been celebrated for catalyzing revolutionary breakthroughs, yet these advancements simultaneously introduce intricate challenges that warrant thorough investigation. These challenges encompass safety protocols, potential environmental detriments, and the complex geopolitical landscape surrounding nuclear proliferation and disarmament. This comprehensive review embarks on a deep exploration of nuclear isotopes, elucidating their nuanced classifications, wide-ranging applications, intricate governing policies, and the multifaceted impacts of their unintended emissions or leaks. Furthermore, the study meticulously examines the cutting-edge remediation techniques currently employed to counteract nuclear contamination while projecting future innovations in this domain. By weaving together historical context, current applications, and forward-looking perspectives, this review offers a panoramic view of the nuclear isotope landscape. In conclusion, the significance of nuclear isotopes cannot be understated. As we stand at the crossroads of technological advancement and ethical responsibility, this review underscores the paramount importance of harnessing nuclear isotopes' potential in a manner that prioritizes safety, sustainability, and the greater good of humanity.

Effect of silver vanadate on the antibiofilm, adhesion and biocompatibility properties of denture adhesive

Aim: To evaluate the biological and mechanical properties of an adhesive with nanostructured silver vanadate (AgVO3). Materials & methods: Specimens in poly(methyl methacrylate) (PMMA) were treated with Ultra Corega Cream (UCCA) denture adhesive with or without AgVO3. Biofilms of Candida albicans, Candida glabrata and Streptococcus mutans were grown and the viable cells counted. Fluorescence microscopy was used. The viability of the VERO cell and adhesive strength were evaluated. Results: All concentrations of AgVO3 reduced the biofilm formation and showed no cytotoxic effect. At 5 min and 24 h, UCCA with 5 and 10% AgVO3 showed better performance, respectively. Conclusion: AgVO3 promoted the antibiofilm activity of the adhesive, with a positive effect on the adhesive strength, and was biocompatible.

Quantifying sodium hypochlorite content in hypochlorite-based disinfectants via phase-conversion headspace technique

In this work, a novel and efficient approach for sodium hypochlorite analysis is proposed via phase-conversion headspace technique, which is based on the gas chromatography (GC) detection of generated carbon dioxide (CO2) from the redox reaction of sodium hypochlorite with sodium oxalate. The data obtained by the proposed method suggest the high detecting precision and accuracy. In addition, the method has low detection limits (limit of quantification (LOQ) = 0.24 μg/mL), and the recoveries of added standard ranged from 98.33 to 101.27 %. The proposed phase-conversion headspace technique is efficient and automated, thereby offering an efficient strategy for highly efficient analysis of sodium hypochlorite and related products.

Disinfection of wastewater by a complete equipment based on a novel ultraviolet light source of microwave discharge electrodeless lamp: Characteristics of bacteria inactivation, reactivation and full-scale studies

Ultraviolet (UV) light is widely used for wastewater disinfection. Traditional electrode-excited UV lamps, such as low-pressure mercy lamps (LPUV), encounter drawbacks like electrode aging and rapid light attenuation. A novel UV source of microwave discharge electrodeless lamp (MDEL) has aroused attention, yet its disinfection performance is unclear and still far from practical application. Here, we successfully developed a complete piece of equipment based on MDELs and achieved the application for disinfection in wastewater treatment plants (WWTPs). The light emitted by an MDEL (MWUV) shared a spectrum similar to that of LPUV, with the main emission wavelength at 254 nm. The inactivation rate of Gram-negative E. coli by MWUV reached 4.5 log at an intensity of 1.6 mW/cm2 and a dose of 20 mJ/cm2. For Gram-positive B. subtilis, an MWUV dose of 50 mJ/cm2 and a light intensity of 1.2 mW/cm2 reached an inactivation rate of 3.4 log. A higher MWUV intensity led to a better disinfection effect and a lower photoreactivation rate of E. coli. When inactivated by MWUV with an intensity of 1.2 mW/cm2 and a dose of 16 mJ/cm2, the maximum photoreactivation rate and reactivation rate constant Kmax of E. coli were 0.63 % and 0.11 % h-1 respectively. Compared with the photoreactivation, the dark repair of E. coli was insignificant. The full-scale application of the MDEL equipment was conducted in two WWTPs (10,000 m3/d and 15,000 m3/d). Generally 2-3 log inactivation rates of fecal coliforms in secondary effluent were achieved within 5-6 s contact time, and the disinfected effluent met the emission standard (1000 CFU/L). This study successfully applied MDEL for disinfection in WWTPs for the first time and demonstrated that MDEL has broad application prospects.

A Day in the Life of a Surgical Instrument: The Cycle of Sterilization

Surgeons must be confident that the instruments they use do not pose risk of infection to patients due to bioburden or contamination. Despite this importance, surgeons are not necessarily aware of the steps required to ensure that an instrument has been properly sterilized, processed, and prepared for the next operation. At the end of an operation, instruments must be transported to the sterile processing unit. There, instruments are decontaminated before being sterilized by heat, chemical, or radiation-based methods. Following this, they are stored before being brought back into use. This review highlights the intricacies of the processing of surgical instruments at the conclusion of an operation so that they are ready for the next one.

Progress of disinfection catalysts in advanced oxidation processes, mechanisms and synergistic antibiotic degradation

Human diseases caused by pathogenic microorganisms make people pay more attention to disinfection. Meanwhile, antibiotics can cause microbial resistance and increase the difficulty of disease treatment, resulting in risk of triggering a vicious circle. Advanced oxidation process (AOPs) has been widely studied in the field of synergistic treatment of the two contaminates. This paper reviews the application of catalytic materials and their modification strategies in the context of AOPs for disinfection and antibiotic degradation. It also delves into the mechanisms of disinfection such as the pathways for microbial inactivation and the related influencing factors, which are essential for understanding the pivotal role of catalytic materials in disinfection principles by AOPs. More importantly, the exploratory research on the combined use of AOPs for disinfection and antibiotic degradation is discussed, and the potential and prospects in this field is highlighted. Finally, the limitations and challenges associated with the application of AOPs in disinfection and antibiotic degradation are summarized. It aims to provide a starting point for future research efforts to facilitate the widespread use of advanced oxidation processes in the field of public health.

Patterns of Resident Activity and Their Impact on Environmental Parameters in Residential Apartments: Case Study and Implications for Design and Management

In the quest to optimize residential environments for health and sustainability, understanding the interaction between pedestrian dynamics and environmental parameters is crucial. This study delves into this intersection by conducting a detailed spatial‐temporal analysis within an apartment building. The research reveals pivotal insights about the relationship between pedestrian flow and environmental quality. Key findings reveal distinct patterns in pedestrian traffic, with two main peaks in early morning and late evening, accounting for approximately 24% of daily movement. The study identifies a pronounced preference for upward elevator use, reflecting residents’ lifestyle and floor‐level choices. Importantly, we observed variable correlations between pedestrian flow and environmental pollutants. Pollutants like PM2.5 and carbon monoxide exhibited weak correlations, while noise, TVOC, formaldehyde, and ozone showed stronger associations with human movement. The research uncovered significant spatial differences in pollutant levels across the building, with higher particulate matter and ozone levels in the seventh‐floor elevator room. The data suggest a need for tailored pollution management strategies, especially for noise and hazardous compounds like formaldehyde and ozone, which exceed safety limits in certain areas. Our findings offer critical insights for the design and management of residential environments, emphasizing the importance of considering both pedestrian flow and environmental factors in optimizing living spaces for health and efficiency.

Fluorimetric determination of aqueous formaldehyde employing heating and ultrasound-assisted approach through its derivatization with a ß-diketone-nickel(2+) complex immobilized in a PMMA flow cell

Formaldehyde (FA) is a highly toxic substance present in many matrices, including freshwater as well as found in natural mechanisms such as rainfall and combustion of organic matter. Consumption of water contaminated with high levels of FA can cause severe short-term or long-term health problems. Due to these health risks, procedures are necessary to determine and quantify FA in aqua sources This paper reports on a study of fluorimetric determination of FA using a nickel(2 + )-diketonate coordination compound immobilized as a solid precursor. The compound was characterized by electronic absorption, Fourier transform infrared (FTIR) spectroscopy, X-ray diffraction (XRD), thermogravimetry (TG), optical microscopy (OM), and scanner electron microscopy (SEM). The methodology was based on the reaction of the synthesized compound with an ammoniacal buffer generating a selective reagent for formaldehyde: fluoral-P. The product of the reaction generates 3,5-diacetyl-1,4-dihydrolutidine (DDL), which is responsible for the fluorescence of the system. Several parameters such as temperature, duration of heating time, and dilution effect with the best effects were studied to carry out FA determination. Under the optimum experimental conditions, a linear response ranging from 1.0 to 10.0 mg/L FA (R = 0.997 and n = 10), and a detection (3σ criterion) and quantification (10 σ criterion) limit estimated at 0.129 and 0.389 mg/L, respectively were achieved. The FA analysis was able to be conducted in 05 min with a relative standard deviation estimated at 1.10 %.

A review on sterilization methods of environmental decontamination to prevent the coronavirus SARS-CoV-2 (COVID-19 virus): A new challenge towards eco-friendly solutions

In recent years, the COVID-19 pandemic is currently wreaking havoc on the planet. SARS-CoV-2, the Severe Acute Respiratory Syndrome Coronavirus, is the current term for this outbreak. Reports about this novel coronavirus have been presented since the pandemic's breakout, and they have demonstrated that it transmits rapidly from person to person, primarily by droplets in the air. Findings have illustrated that SARS-CoV-2 can survive on surfaces from hours to days. Therefore, it is essential to find practical solutions to reduce the virus's impact on human health and the environment. This work evaluated common sterilization methods that can decontaminate the environment and items. The goal is that healthcare facilities, disease prevention organizations, and local communities can overcome the new challenge of finding eco-friendly solutions. Further, a foundation of information encompassing various sterilization procedures and highlighting their limits to choose the most appropriate method to stop disease-causing viruses in the new context has been presented. The findings of this crucial investigation contribute to gaining insight into the comprehensive sterilization approaches against the coronavirus for human health protection and sustainable environmental development.

Ag2O-Containing Biocidal Interpolyelectrolyte Complexes on Glass Surfaces-Adhesive Properties of the Coatings

Biocidal coatings are of great interest to the healthcare system. In this work, the biocidal activity of coatings based on a complex biocide containing polymer and inorganic active antibacterial components was studied. Silver oxide was distributed in a matrix of a positively charged interpolyelectrolyte complex (IPEC) of polydiallyldimethylammonium chloride (PDADMAC) and sodium polystyrene sulfonate (PSS) using ultrasonic dispersion, forming nanoparticles with an average size of 5-6 nm. The formed nanoparticles in the matrix are not subject to agglomeration and changes in morphology during storage. It was found that the inclusion of silver oxide in a positively charged IPEC allows a more than 4-fold increase in the effectiveness of the complex biocide against E. coli K12 in comparison with the biocidal effect of PDADMAC and IPEC. Polycation, IPEC, and the IPEC/Ag2O ternary complex form coatings on the glass surface due to electrostatic adsorption. Adhesive and cohesive forces in the resulting coatings were studied with micron-scale coatings using dynamometry. It was found that the stability of the coating is determined primarily by adhesive interactions. At the macro level, it is not possible to reliably identify the role of IPEC formation in adhesion. On the other hand, use of the optical tweezers method makes it possible to analyze macromolecules at the submicron scale and to evaluate the multiple increase in adhesive forces when forming a coating from IPEC compared to coatings from PDADMAC. Thus, the application of ternary IPEC/Ag2O complexes makes it possible to obtain coatings with increased antibacterial action and improved adhesive characteristics.

Well-designed protein amyloid nanofibrils composites as versatile and sustainable materials for aquatic environment remediation: A review

Amyloid nanofibrils (ANFs) are supramolecular polymers originally classified as pathological markers in various human degenerative diseases. However, in recent years, ANFs have garnered greater interest and are regarded as nature-based sustainable biomaterials in environmental science, material engineering, and nanotechnology. On a laboratory scale, ANFs can be produced from food proteins via protein unfolding, misfolding, and hydrolysis. Furthermore, ANFs have specific structural characteristics such as a high aspect ratio, good rigidity, chemical stability, and a controllable sequence. These properties make them a promising functional material in water decontamination research. As a result, the fabrication and application of ANFs and their composites in water purification have recently gained considerable attention. Despite the large amount of literature in this field, there is a lack of systematic review to assess the gap in using ANFs and their composites to remove contaminants from water. This review discusses significant advancements in design techniques as well as the physicochemical properties of ANFs-based composites. We also emphasize the current progress in using ANFs-based composites to remove inorganic, organic, and biological contaminants. The interaction mechanisms between ANFs-based composites and contaminants are also highlighted. Finally, we illustrate the challenges and opportunities associated with the future preparation and application of ANFs-based composites. We anticipate that this review will shed new light on the future design and use of ANFs-based composites.

Influence of cold atmospheric pressure plasma treatment of Spirulina platensis slurry over biomass characteristics

Cold atmospheric pressure plasma (CAPP) technique is an innovative non-thermal approach for food preservation and decontamination. This study aimed to evaluate the effect of CAPP power density on microorganism inactivation and quality of Spirulina platensis (S. platensis) slurry. 91.31 ± 1.61% of microorganism were inactivated within 2.02 ± 0.11 min by 26.67 W/g CAPP treatment under 50 ℃. Total phenolic, Chlorophyll-a (Chl-a), and carotenoids contents were increased by 20.51%, 63.55%, and 70.04% after 20.00 W/g CAPP treatment. Phycobiliproteins (PBPs), protein, intracellular polysaccharide, and moisture content of S. platensis was decreased, while vividness, lightness, color of yellow and green, antioxidant activity, Essential Amino Acid Index were enhanced after CAPP treatment. The nutrient release and filaments breakage of CAPP-treated S. platensis improved its bio-accessibility. The findings provided a deep understanding and insight into the influence of CAPP treatment on S. platensis, which were meaningful for optimizing its sterilization and drying processing condition.

Biosynthesis of silver nanoparticles using nitrate reductase from Aspergillus terreus N4 and their potential use as a non-alcoholic disinfectant

Green technology has been developed for the quick production of stabilized silver nanoparticles (AgNPs), with the assistance of nitrate reductase from an isolated culture of Aspergillus terreus N4. The organism's intracellular and periplasmic fractions contained nitrate reductase, with the former demonstrating the highest activity of 0.20 IU/g of mycelium. When the fungus was cultivated in a medium comprising 1.056% glucose, 1.836% peptone, 0.3386% yeast extract, and 0.025% KNO3, the greatest nitrate reductase productivity of 0.3268 IU/g was achieved. Statistical modeling via response surface methodology was used to optimize the enzyme production. The periplasmic and intracellular enzyme fractions were found to convert Ag+ to Ag0, initiating synthesis within 20 min, with predominant nanoparticle sizes between 25 and 30 nm. By normalizing the effects of temperature, pH, AgNO3 concentration, and mycelium age with a variable shaking period for enzyme release, the production of AgNPs with the periplasmic fraction was optimized. The synthesis of nanoparticles occurred at temperatures of 30, 40, and 50 °C, with the highest yield observed at 40 and 50 °C during shorter incubation periods. Similarly, the nanoparticles were synthesized at pH levels of 7.0, 8.0, and 9.0, with the greatest production observed at pH 8.0 and 9.0 at lower incubation periods. The antimicrobial activity of AgNPs was demonstrated against common foodborne pathogens, including Staphylococcus aureus and Salmonella typhimurium, indicating their potential as non-alcoholic disinfectants.

Simultaneous Irradiation with UV-A, -B, and -C Lights Promotes Effective Decontamination of Planktonic and Sessile Bacteria: A Pilot Study

Surfaces in highly anthropized environments are frequently contaminated by both harmless and pathogenic bacteria. Accidental contact between these contaminated surfaces and people could contribute to uncontrolled or even dangerous microbial diffusion. Among all possible solutions useful to achieve effective disinfection, ultraviolet irradiations (UV) emerge as one of the most "Green" technologies since they can inactivate microorganisms via the formation of DNA/RNA dimers, avoiding the environmental pollution associated with the use of chemical sanitizers. To date, mainly UV-C irradiation has been used for decontamination purposes, but in this study, we investigated the cytotoxic potential on contaminated surfaces of combined UV radiations spanning the UV-A, UV-B, and UV-C spectrums, obtained with an innovative UV lamp never conceived so far by analyzing its effect on a large panel of collection and environmental strains, further examining any possible adverse effects on eukaryotic cells. We found that this novel device shows a significant efficacy on different planktonic and sessile bacteria, and, in addition, it is compatible with eukaryotic skin cells for short exposure times. The collected data strongly suggest this new lamp as a useful device for fast and routine decontamination of different environments to ensure appropriate sterilization procedures.

Antioxidant and Antiaging Activity of Fermented Coix Seed Polysaccharides on Caenorhabditis elegans

Aging is closely related to many diseases and is a long-term challenge that humans face. The oxidative damage caused by the imbalance of free radicals is an important factor in aging. In this study, we investigate the antioxidant and antiaging activities of fermented coix seed polysaccharides (FCSPs) via in vitro and in vivo experiments. The FCSPs were extracted by fermenting coix seed with Saccharomyces cerevisiae for 48 h and utilizing water-extracted coix seed polysaccharides (WCSPs) as a control. Their antiaging activity and mechanism were evaluated based on the antiaging model organism Caenorhabditis elegans (C. elegans). The results showed that the molecular weight of the FCSPs extracted by fermentation was smaller than that of the WCSPs, making them more easily absorbed and utilized. At a concentration of 5 g/L, the FCSPs' capacity to scavenge the DPPH·, ABTS+·, OH·, and O2-· radicals was greater than the WCSPs' capacity by 10.09%, 14.40%, 49.93%, and 12.86%, respectively. Moreover, C. elegans treated with FCSPs exhibited higher antioxidant enzyme activities and a lower accumulation of malonaldehyde. By inhibiting the expression of the pro-aging genes daf-2 and age-1, and upregulating the expression of the antiaging genes daf-16, sod-3, skn-1, and gcs-1 in the insulin/insulin-like growth factor-1 (IIS) signaling pathway, the FCSPs could effectively enhance stress tolerance and delay C. elegans aging. The lifespan of C. elegans in the FCSPs group was 5.91% higher than that of the WCSPs group. In conclusion, FCSPs exert better antioxidant and antiaging effects than WCSPs, which can act as a potential functional ingredient or supplement in food.

Modelling of Nonthermal Dielectric Barrier Discharge Plasma at Atmospheric Pressure and Role of Produced Reactive Species in Surface Polymer Microbial Purification

A nonthermal atmospheric plasma reactor was used to sterilize polymer surfaces and satisfy safety constraints in a biological medium. A 1D fluid model was developed using COMSOL Multiphysics software^® 5.4 with a helium-oxygen mixture at low temperature for the decontamination of bacteria on polymer surfaces. An analysis of the evolution of the homogeneous dielectric barrier discharge (DBD) was carried out through studying the dynamic behavior of the discharge parameters including the discharge current, the consumed power, the gas gap voltage, and transport charges. In addition, the electrical characteristics of a homogeneous DBD under different operating conditions were studied. The results shown that increasing voltage or frequency caused higher ionization levels and maximum increase of metastable species' density and expanded the sterilization area. On the other hand, it was possible to operate plasma discharges at a low voltage and a high density of plasma using higher values of the secondary emission coefficient or permittivity of the dielectric barrier materials. When the discharge gas pressure increased, the current discharges declined, which indicated a lower sterilization efficiency under high pressure. A short gap width and the admixture of oxygen were needed for sufficient bio-decontamination. Plasma-based pollutant degradation devices could therefore benefit from these results.