Effects Of Inactivation Research Articles

Evaluation of two household decontamination methods on protective mask materials and disinfection effects

Abstract In order to find affective disinfection methods for general public to reuse protective mask, which could address supply shortages in the period of epidemic, household ovens and household ultraviolet disinfection cabinets were used as decontamination tools, and the influence of decontamination process on the protective performance of masks including PFE and TIL, as well as virus (PV I and MHV) inactivation effect were completely evaluated. It was found that the dry heat and UVGI decontamination with household devices had a little impact on PFE or TIL of masks, which indicated that two process had little effect on mask material and face seal fit. The virus inactivation results showed that dry heat decontamination could effectively inactivate the virus on the masks, and UVGI decontamination could not completely inactivate the virus caused by the special shape of masks, which could be concluded that dry heat decontamination with household oven was a feasible method to reuse the mask, and UVGI decontamination was not recommended. This study had guiding significance for the decontamination and reuse of masks by the general public.

Inactivation effect and mechanism of Pediastrum by in-liquid pulsed discharge plasma

The issue of eutrophication in river and lake ecosystems is escalating, resulting in harmful algal blooms that adversely impact the aquatic environment. Thus, it is crucial to develop new technology that can effectively inactivate algae without causing secondary pollution to the water body. This work uses in-liquid pulsed discharge plasma technique to inactivate Pediastrum. The research investigates variations in inactivation ratios, chlorophyll-a concentrations, and the inactivation mechanisms under different discharge conditions. The results indicate that the optimal inactivation effect is achieved at a peak voltage of 30 kV, an electrode spacing of 7 mm, and a discharge duration of 20 min, resulting in a 90 % inactivation ratio and a reduction in chlorophyll-a concentration from 1.31 mg/L to 0.63 mg/L (on the fourth day of re-culturing). The discharge process generates strong shock waves, ultraviolet lights, and significant amounts of oxidizing agents, such as· O, H2O2, O3, leading to cell damage, cell wall disruption, and enzyme activity reduction, thereby achieving effective inactivation.

Inactivation effect of extracts of gardenia fruit, licorice and Torilis japonica fruit against Bacillus spores

Inactivation effect of extracts of gardenia fruit, licorice and Torilis japonica fruit against Bacillus spores

Comparison of plasma-activated saline prepared with plasma gases with different N2/O2 ratios activated by gliding arc discharge

Methicillin-resistant Staphylococcus aureus (MRSA) presents a significant threat due to the multiple resistance to antibiotics, leading to severe and challenging-to-treat infections. Plasma-activated saline (PAS) prepared by plasma gases, could efficiently inactivate various pathogenic bacteria including both sensitive and antibiotic-resistant bacteria. In this study, the PAS was prepared by plasma gases with different ratios of N2 and O2 activated by gliding arc discharge. First, the gaseous reactive species in the plasma gases were compared, revealing that the highest levels of NO x including NO2 and N2O5 were generated in the gases with the N2/O2 ratios of 4:6, 5:5, and 6:4. Subsequently, the PAS prepared by the two plasma-activated gases at the N2/O2 ratios of 5:5 and 6:4 exhibited the strongest inactivation effects on both planktic MRSA and biofilms. Furthermore, the aqueous reactive species in the PAS exhibited varied change trends with the increasing N2/O2 ratios. Additionally, ultraviolet spectroscopy combined with the probe of N, N-diethyl-p-phenylenediamine was applied for the detection of O2NOO− in the PAS, and the levels of O2NOO− in the PAS were positively correlated with the inactivation effects. Moreover, the PAS induced varying levels of nitration modification on the soluble proteins in MRSA cells, which were related to the intensities of O2NOO− in the PAS. This study regulated the reactive species in the PAS through gas composition and explored the inactivation mechanism of the PAS, providing a new strategy to promote the preparation efficiency of plasma-activated solutions for biomedical applications.

Structural Simplification of Podophyllotoxin: Discovery of γ-Butyrolactone Derivatives as Novel Antiviral Agents for Plant Protection.

Natural products are a valuable resource for the discovery of novel crop protection agents. A series of γ-butyrolactone derivatives, derived from the simplification of podophyllotoxin's structure, were synthesized and assessed for their efficacy against tobacco mosaic virus (TMV). Several derivatives exhibited notable antiviral properties, with compound 3g demonstrating the most potent in vivo anti-TMV activity. At 500 μg/mL, compound 3g achieved an inactivation effect of 87.8%, a protective effect of 71.7%, and a curative effect of 67.7%, surpassing the effectiveness of the commercial plant virucides ningnanmycin and ribavirin. Notably, the syn-diastereomer (syn-3g) exhibited superior antiviral activity compared to the anti-diastereomer (anti-3g). Mechanistic studies revealed that syn-3g could bind to the TMV coat protein and interfere with the self-assembly process of TMV particles. These findings indicate that compound 3g, with its simple chemical structure, could be a potential candidate for the development of novel antiviral agents for crop protection.

The Optimization of Aerobic Bacteria Inactivation in Tilapia (Oreochromis niloticus) Fillets using Micro-Nano Bubbles of Carbon Dioxide and Shelf-Life Extension

This study aims to examine the influence of NaOCl, NaCl and contact time on the inactivation of aerobic bacteria in tilapia fillets treated with micro-nano bubbles of CO2 (CO2 MNB) in a washing process of fish fillets, and compared to soaking with tap water and untreated fillets for their shelf-life extensions. Response surface methodology (RSM) with a central composite design was used to compare and predict of the inactivation effects. The fish fillets were soaked in a NaOCl solution before washing with a NaCl solution and CO2 MNB produced from an MNB generator system, maintaining the liquid temperature in the range of 4–7 °C for all experiments. According to the regression analysis from the experimental design, aerobic bacteria inactivation was reduced by 1.509 log CFU/g at 100 mg/L NaOCl, 10%w/v NaCl, and a contact time of 32 min with CO2 MNB. The experimental value of the reduction of aerobic bacteria by 1.503 ± 0.009 log CFU/g (before washing 5.623 log CFU/g; after washing 4.120 log CFU/g) was found after treatment under the aforementioned condition. The number of aerobic bacteria counted on the tilapia fillets treated with the upper condition after being stored at 4 ± 2 °C for 7 d was below the acceptable limits, but untreated and treated with tap water had bacteria counts exceeding the upper microbial limit (6 log CFU/g). The combined results showed that the NaOCl, NaCl solution and CO2 MNB treatment could extend the storage time by more than 7 d.

Don't ignore the middle: Distinct mnemonic functions of intermediate hippocampus.

The dorsal region of the hippocampus (dHC) mediates many of the mnemonic functions traditionally associated with the hippocampus proper, such as spatial and episodic memory, whereas ventral hippocampus (vHC) has been extensively implicated in emotional memory and motivational processes. By contrast, the functions of the intermediate hippocampus (iHC) are far less understood. In this study, we aimed to investigate the mnemonic functions of iHC by reversibly inactivating iHC prior to testing memory in behavioral tasks dependent on the integrity of dHC, iHC, or vHC, namely, rapid place water maze, inhibitory avoidance, spontaneous alternation, and temporal ordering of odors. Given our previous findings showing that dHC and vHC are involved in mnemonic control of ingestive behavior, we also assessed the effects of iHC inactivation on sucrose intake. The results showed that pharmacological inhibition of iHC impairs rapid place water maze memory, which has been previously shown to be dependent on iHC but not dHC or vHC. iHC inactivation does not impact memory dependent on dHC (spontaneous alternation), vHC (temporal odor memory), or either dHC or vHC (inhibitory avoidance), and only modestly affects sucrose intake. These findings provide support for the involvement of iHC in mnemonic functions that are distinct from dHC and vHC and highlight the need to further advance our understanding of the functions of this hippocampal region that has been relatively understudied.

Gaseous ozone inactivation of Bacillus atrophaeus spores on ceramic and porcelain tiles

In this study, we investigated the ozone inactivation efficiency of Bacillus atrophaeus spores attached to various tile surfaces. Eight different types of tiles were employed, considering factors such as porosity (ceramic, porcelain), color (white, black), and glossiness (matte, glossy). Inactivation was performed by exposing the spore-loaded tiles to ozone gas for a specified duration. The inactivation efficiencies of ozone gas on different tile surfaces were compared by analyzing the colony-forming units of desorbed Bacillus atrophaeus cultured in a growth medium. Results revealed a reduction in colony counts with increasing ozone exposure time, indicating a proportional enhancement in inactivation effectiveness on ozone exposure time. After exposure to ozone gas for 30 min or longer, more than 90% of spores on each tile were inactivated. Regarding porosity, ceramic tiles exhibited slightly superior inactivation effects compared to porcelain tiles. Additionally, in terms of glossiness, glossy tiles demonstrated better inactivation effects than matte tiles. However, no significant differences were observed in inactivation effects based on the color of the tiles.

Inactivation of Fusarium verticilliordes by dielectric barrier discharge plasma and its mechanism

Fusarium is a kind plant pathogenic fungus, resulting in severe crops infection and food safety issues. The development of novel strategy to inactive Fusarium is in urgent need. In this study, the inactivation effect and mechanism of dielectric barrier discharge (DBD) plasma on Fusarium verticillioides was studied. The results showed that the fungicidal effect of DBD plasma was positively correlated with the voltage strength and treatment time, which could reach 100% sterilizing rate at 60–80 V. The scanning electron microscope (SEM) observation indicated the integrity of the cell wall and cell membrane of the treated F. verticilliordes was damaged, leading to leakage of the contents. The changes of mitochondrial membrane potential, adenosine 5′-triphosphate (ATP) content, cell viability and reactive substances (intracellular reactive oxygen species (ROS), intracellular hydrogen peroxide (H2O2), ozone (O3) and reactive nitrogen species (RNS) (NO2−, NO3−, etc.)) were also tested to better understand the fungicidal mechanism of cold plasma. These results demonstrated DBD plasma could be a promising technique for Fusarium inactivation in food.

Novel Halogenated Curcumin-Mediated Photodynamic Inactivation for the Preservation of Small Yellow Croaker (Larimichthys polyactis).

A novel class of halogenated curcumin, X-Cur (X = F, Cl, or Br), was synthesized, and its photosensitivity was evaluated. The results showed that Br-Cur with the highest singlet oxygen (1O2) generation capacity exhibited a better photodynamic inactivation (PDI) effect on the small yellow croaker (Larimichthys polyactis) than curcumin. This was attributed to the heavy atom effect of Br, which resulted in Br-Cur having the smallest singlet-triplet energy difference ΔEst(S1-T3) (0.140 eV) and the largest spin-orbit coupling value (0.642262 cm-1). When L. polyactis was treated with 0.025 wt % Br-Cur and exposed to blue LED irradiation (450 nm, 20 mW/cm2) for 20 min, the increase in the total volatile basic nitrogen content (28.23 ± 2.38 mg/100 g on day 6), pH, and total viable count (6.13 ± 0.06 log CFU/g on day 6) could be effectively controlled. Accordingly, Br-Cur is a promising photosensitizer for PDI preservation.

Evaluating bentonite clay’s potential in protecting intestinal flora and alleviating pseudomembranous colitis following antibiotic usage

As the most commonly used drugs, antibiotics have several adverse effects. When intravenous broad-spectrum antibiotics are administered for infections outside the gut, they are also released into the gut, upsetting the natural balance of flora and potentially causing opportunistic infections there. Pseudomembranous colitis induced by the excessive growth of Clostridioides difficile following antibiotic administration and disruption of the normal gut flora is a main consequence of antibiotic therapy. Unfortunately, effective strategies to mitigate the damage caused by antibiotics to the microbiota remain elusive, with limited information available on the subject. Several studies have examined the effects of enzymatic inactivation of specific antibiotics, but non-enzymatic inactivation of antibiotics has been explored to a lesser extent, resulting in the introduction of only a restricted number of products. We believe that bentonite clay, an underutilized substance that exhibits promising features for counteracting the unfavorable effects of antibiotics has a high potential to circumvent the side effects of antibiotics. It is a cost-effective and safe and has garnered significant attention in the medical history, predominantly for its superior adsorption properties. Given the diverse characteristics of bentonite clay, capacity to protect the natural flora, antibacterial and anti-inflammatory traits, and its contribution to wound healing, it is plausible to assume that bentonite clay exhibits significant potential in mitigating the detrimental consequences of antibiotic on the natural gut microbiota and following pseudomembranous colitis. Further research is necessary to unravel the full extent of its therapeutic effects in combating this condition.

Blackthorn fruit peel polyphenol extracts and photodynamic effect under blue light against Listeria monocytogenes

Photodynamic inactivation is an emerging antimicrobial treatment that can be enhanced by employing exogenous photosensitizers to eradicate foodborne pathogens. This study investigated a novel combinatory strategy to eradicate Listeria monocytogenes using blackthorn fruit peel (BFP) and blue light (BL). Extracts of BFP were characterized in terms of polyphenolic content, individual constituents, and antioxidant and antimicrobial activity. The concentration of phenolic compounds and antioxidant activity were both found to be determinants of antimicrobial activity. It was further speculated that flavonols, predominantly quercetin and rutin, were responsible for the activity of BFP against L. monocytogenes. A combination of BFP and BL resulted in a rapid inactivation of the pathogen by up to 4 log CFU/mL at 58.5 J/cm2, corresponding to 15 min BL illumination. Flow cytometry analysis revealed that the bacterial cells lost activity and suffered extensive membrane damage, exceeding 90% of the population. After photosensitizing L. monocytogenes with the BFP constituents quercetin and rutin, a 1.3-log reduction was observed. When applied together, these compounds could inflict the same damaging effect on cells as they did individually when effects were added. Therefore, the results indicate that BFP represents a natural source of (pro-)photosensitizers, which act additively to create inactivation effects. This study may help identify more effective plant-based photosensitizers to control L. monocytogenes in food-related applications.

Efficacy, kinetics, inactivation mechanism and application of cold plasma in inactivating Alicyclobacillus acidoterrestris spores

As spores of Alicyclobacillus acidoterrestris can survive traditional pasteurization, this organism has been suggested as a target bacterium in the fruit juice industry. This study aimed to investigate the inactivation effect of cold plasma on A. acidoterrestris spores and the mechanism behind the inactivation. The inactivation effect was detected by the plate count method and described by kinetic models. Scanning electron microscopy (SEM), transmission electron microscopy (TEM), the detection of dipicolinic acid (DPA) release and heat resistance detection, the detection and scavenging experiment of reactive species, and cryo-scanning electron microscopy were used to explore the mechanism of cold plasma inactivation of A. acidoterrestris. The results showed that cold plasma can effectively inactivate A. acidoterrestris spores in saline with a 3.0 ± 0.3 and 4.4 ± 0.8 log reduction in CFU/mL, for 9 and 18 min, respectively. The higher the voltage and the longer the treatment time, the stronger the overall inactivation effect. However, a lower gas flow rate may increase the probability of spore contact with reactive species, resulting in better inactivation results. The biphasic model fits the survival curves better than the Weibull model. SEM and TEM revealed that cold plasma treatment can cause varying degrees of damage to the morphology and structure of A. acidoterrestris spores, with at least 50 % sustaining severe morphological and structural damage. The DPA release and heat resistance detection showed that A. acidoterrestris spores did not germinate but died directly during the cold plasma treatment. 1O2 plays the most important role in the inactivation, while O3, H2O2 and NO3− may also be responsible for inactivation. Cold plasma treatment for 1 min reduced A. acidoterrestris spores in apple juice by 0.4 ± 0.0 log, comparable to a 12-min heat treatment at 95 °C. However, as the treatment time increased, the survival curve exhibited a significant tailing phenomenon, which was most likely caused by the various compounds in apple juice that can react with reactive species and exert a physical shielding effect on spores. Higher input power and higher gas flow rate resulted in more complete inactivation of A. acidoterrestris spores in apple juice. What's more, the high inactivation efficiency in saline indicates the cold plasma device provides a promising alternative for controlling A. acidoterrestris spores during apple washing. Overall, our study provides adequate data support and a theoretical basis for using cold plasma to inactivate A. acidoterrestris spores in the food industry.

Disruption of Cell Membranes and Redox Homeostasis as an Antibacterial Mechanism of Dielectric Barrier Discharge Plasma against Fusarium oxysporum.

Direct barrier discharge (DBD) plasma is a potential antibacterial strategy for controlling Fusarium oxysporum (F. oxysporum) in the food industry. The aim of this study was to investigate the inhibitory effect and mechanism of action of DBD plasma on F. oxysporum. The result of the antibacterial effect curve shows that DBD plasma has a good inactivation effect on F. oxysporum. The DBD plasma treatment severely disrupted the cell membrane structure and resulted in the leakage of intracellular components. In addition, flow cytometry was used to observe intracellular reactive oxygen species (ROS) levels and mitochondrial membrane potential, and it was found that, after plasma treatment, intracellular ROS accumulation and mitochondrial damage were accompanied by a decrease in antioxidant enzyme activity. The results of free fatty acid metabolism indicate that the saturated fatty acid content increased and unsaturated fatty acid content decreased. Overall, the DBD plasma treatment led to the oxidation of unsaturated fatty acids, which altered the cell membrane fatty acid content, thereby inducing cell membrane damage. Meanwhile, DBD plasma-induced ROS penetrated the cell membrane and accumulated intracellularly, leading to the collapse of the antioxidant system and ultimately causing cell death. This study reveals the bactericidal effect and mechanism of the DBD treatment on F. oxysporum, which provides a possible strategy for the control of F. oxysporum.

The synergistic effect of photodynamic and sonodynamic inactivation against Candida albicans biofilm.

Candida albicans biofilm can cause diseases that are resistant to conventional antifungal agents. Photodynamic (PDI), sonodynamic (SDI), and sonophotodynamic (SPDI) inactivation have arisen as promising antimicrobial strategies. This study evaluated these treatments mediated by curcumin against C. albicans biofilms. For this, C. albicans biofilms were submitted to PDI, SDI, or SPDI with different light and ultrasound doses, then, the viability assay was performed to measure the effectiveness. Finally, a mathematical model was suggested to fit acquired experimental data and understand the synergistic effect of light and ultrasound in different conditions. The results showed that SPDI, PDI, and SDI reduced the viability in 6 ± 1; 1 ± 1; and 2 ± 1 log, respectively, using light at 60 J/cm2, ultrasound at 3 W/cm2, and 80 μM of curcumin. The viability reduction was proportional to the ultrasound and light doses delivered. These results encourage the use of SPDI for the control of microbial biofilm.

Numerical analysis of polyphenol oxidase inactivation in non-Newtonian characteristic liquid food with high viscosity during radio frequency treatment

Enzymatic browning is one of the main problems in the food industry, especially in juice and jam processing. An efficient approach to reduce enzymatic browning is to inactivate key polyphenol oxidases (PPO) that cause color reactions. Radio frequency (RF) treatment has advantages of volumetric heating and no chemical residue, making it one of the most potential treatments to replace traditional heating for pasteurization. In this study, a finite element model was established using the commercial software, COMSOL, to investigate the feasibility and effectiveness of PPO inactivation in non-Newtonian characteristic liquid food with high viscosity during pilot-scale RF treatments. The PPO was represented by the tyrosinase, and four concentrations of carboxymethylcellulose (CMC) solutions were considered to have high viscosity and non-Newtonian characteristics for liquid food. The results showed that the relative residual enzyme activity rapidly decreased to 1.2% when the target temperature increased to 70 °C during a batch RF enzyme inactivation. Meanwhile, the simulated and experimental trends were consistent with an acceptable RMSE value. The low-concentration CMC solutions (0.5% and 1.0%) with shorter heating times may be more suitable for developing the batch RF enzyme inactivation technology. During continuous-flow RF enzyme inactivation, the F-value increased with an increase in the solution concentration but sharply decreased with an increase in the volumetric flow rate. The exponential function could be used to describe the relationship between the relative residual enzyme activity and the volumetric flow rate of the CMC solution after RF treatment. The optimal volumetric flow rates for reducing the activity of PPO in 0.5%, 1.0%, 1.5%, and 2.0% CMC solutions to 20% were 426.13, 467.87, 552.05, and 566.07 mL/min, respectively. This study can provide valuable information for inactivating enzymes in non-Newtonian characteristic liquid food with high viscosity.

Dynamic pH regulation drives Nitrosomonas for high-rate stable acidic partial nitritation

How to intensify the ammonia oxidation rate (AOR) is still a bottleneck impeding the technology development for the innovative acidic partial nitritation because the eosinophilic ammonia-oxidizing bacteria (AOB), such as Nitrosoglobus or Nitrosospira, were inhibited by the high-level free nitrous acid (FNA) accumulation in acidic environments. In this study, an innovative approach of dynamic acidic pH regulation control strategy was proposed to realize high-rate acidic partial nitritation driven by common AOB genus Nitrosomonas. The acidic partial nitrification process was carried out in a laboratory-scale sequencing batch moving bed biofilm reactor (SBMBBR) for long-term (700 days) to track the effect of dynamic acidic pH on nitrifying bacterial activity. The results indicated that the influent NH4+-N concentration was about 100 mg/L, the nitrite accumulation ratio was exceeding 90%, and the maximum AOR can reach 14.5 ± 2.6 mg N L−1h−1. Although the half-saturation inhibition constant of NOB (KI_FNA(AOB)) reached 0.37 ± 0.10 mg HNO2N/L and showed extreme adaptability in FNA, the inactivation effect of FNA (6.1 mg HNO2N/L) for NOB was much greater than that of AOB, with inactivation rates of 0.61 ± 0.08 h−1 and 0.06 ± 0.01 h−1, respectively. The effluent pH was gradually reduced to 4.5 by ammonia oxidation process and the periodic FNA concentration reached 6.5 mg HNO2N/L to inactivate nitrite-oxidizing bacteria (NOB) without negatively affecting Nitrosomonas during long-term operation. This result provides new insights for the future implementation of high-rate stabilized acidic partial nitritation by Nitrosomonas.

Effects of PEF on Cell and Transcriptomic of Escherichia coli.

Pulsed electric field (PEF) is an up-to-date non-thermal processing technology with a wide range of applications in the food industry. The inactivation effect of PEF on Escherichia coli was different under different conditions. The E. coli inactivated number was 1.13 ± 0.01 lg CFU/mL when PEF was treated for 60 min and treated with 0.24 kV/cm. The treatment times were found to be positively correlated with the inactivation effect of PEF, and the number of E. coli was reduced by 3.09 ± 0.01 lg CFU/mL after 100 min of treatment. The inactivation assays showed that E. coli was inactivated at electrical intensity (0.24 kV/cm) within 100 min, providing an effective inactivating outcome for Gram-negative bacteria. The purpose of this work was to investigate the cellular level (morphological destruction, intracellular macromolecule damage, intracellular enzyme inactivation) as well as the molecular level via transcriptome analysis. Field Emission Scanning Electron Microscopy (TFESEM) and Transmission Electron Microscope (TEM) results demonstrated that cell permeability was disrupted after PEF treatment. Entocytes, including proteins and DNA, were markedly reduced after PEF treatment. In addition, the activities of Pyruvate Kinase (PK), Succinate Dehydrogenase (SDH), and Adenosine Triphosphatase (ATPase) were inhibited remarkably for PEF-treated samples. Transcriptome sequencing results showed that differentially expressed genes (DEGs) related to the biosynthesis of the cell membrane, DNA replication and repair, energy metabolism, and mobility were significantly affected. In conclusion, membrane damage, energy metabolism disruption, and other pathways are important mechanisms of PEF's inhibitory effect on E. coli.

Effects of proteases inactivation on textural quality of yellow-feathered chicken meat and the possible mechanism based on myofibrillar protein

This study was undertaken to evaluate the impact of proteases inactivation on the textural properties of yellow-feathered chicken (YFC) meat and explore the underlying mechanism driving these changes. The results showed that firmness and shelf life of the YFC meat were significantly improved by the proteases inactivation pretreatment in a dose-dependent manner. Specially, the 40% and 60% residual protease activities were identified to yield textures comparable to the hot-fresh YFC meat. Hydration and water retention of the proteases inactivated YFC meat were also found to be enhanced. Further analysis of myofibrillar protein (MP) revealed that cross-linkages of MP were induced by proteases inactivation with 40% and 60%, evidenced by higher levels of disulfide, carbonyl-amine bonds and di-tyrosine. Additionally, the chemical changes in amino acid residues led to the sequestration of tryptophan residues and the formation of β-sheet structures, accompanied by increased turbidity and particle size of MP. Moreover, water holding capacity, lightness, digestibility and strength of the MP gel were found to be improved. The results would provide insights into potential application of proteases inactivation as a strategy to improve YFC textural quality.

Photodynamic inactivation of antibiotic-resistant bacteria in whole blood using riboflavin photodynamic method.

Treating bacteremia caused by antibiotic-resistant bacteria is a global concern. Antibacterial photodynamic inactivation is a promising strategy to combat it. However, it's challenging to achieve the inactivation of antibiotic-resistant bacteria in whole blood because of its opacity and complexity. We investigated a riboflavin photodynamic method to effectively inactivate antibiotic-resistant bacteria in whole blood. Four strains of antibiotic-resistant bacteria were isolated, identified, and cultured in this research: methicillin-resistant Staphylococcus aureus (MRSA), pan-drug-resistant Acinetobacter baumannii (PDRAB), ESBLs-producing Escherichia coli (EPEC) and pan-drug-resistant Klebsiella pneumoniae (PDRKP). To simulate bacteremia, antibiotic-resistant bacteria was added into whole blood. Whole blood was treated using riboflavin photodynamic method with ultraviolet irradiation (308 nm and 365 nm). The ultraviolet irradiation dose was divided into 18 J/cm2, 36 J/cm2, and 54 J/cm2. Microbial count of antibiotic-resistant bacteria in whole blood was used for evaluating inactivation effectiveness. The roles of red blood cells, lymphocytes, coagulation factors, and platelets in whole blood were assessed. In results, inactivation effectiveness increased as the ultraviolet dose increased from 18 J/cm2 to 54 J/cm2. At the dose of 18 J/cm2, inactivation effectiveness of four antibiotic-resistant bacteria were more than 80%, while only 67% of MRSA. The antibacterial effect was enhanced by the combination of riboflavin photodynamic treatment and antibiotic. The red blood cell function was susceptible to ultraviolet dose. At the dose of 18 J/cm2, hemolysis rate was less than 0.8% and there was no change in levels of ATP and 2,3-DPG. At the same dose, the proliferation, cell killing, and cytokine secretion activities of lymphocytes decreased 20-70%; Factor V and Factor VIII activities decreased 50%; Fibrinogen and platelet function loss significantly but reparable. Consequently, we speculated that riboflavin photodynamic method with a ultraviolet dose of 18 J/cm2 was effective in inactivating four antibiotic-resistant bacteria in whole blood while whole blood function was preserved. We also provided a novel extracorporeal circulation phototherapy mode for treating bacteremia caused by antibiotic-resistant bacteria.