Observation of Traditional Chinese Medicine's Anti-bacterial Effect on the Main Pathogenic Bacteria of Dairy Cow Recessive Mastitis

[Objective]This paper aimed to study the anti-bacterial effect of traditional Chinese medicine on cow recessive mastitis＇ s main pathogenic bacteria and provide basis for its clinical application.[Method]Plating and test-tube methods were used to determine the anti-bacterial diameter,minimum inhibitory concentration（MIC）and minimum bactericidal concentration（MBC）of 20 kinds of traditional Chinese medicine on dairy cow recessive mastitis＇ s clinically isolated main pathogenic bacteria,Staphylococcus aureus and Streptococcus agalactiae.[Conclusion]The results indicated that 7 kinds of traditional Chinese medicine,Herba Taraxaci,Rhizoma Coptidis,Fructus Forsythiae,Herba Andrographis,Radix Scutellar iae,Flos Carthami,Flos Chrysanthemi Indici had strong anti-bacterial effect.

Synthesis of Novel Chitosan Microspheres Grafted with β-Cyclodextrins and Their Adsorption for Iodine for Antibacterial Activities

The novel chitosan microspheres grafted with beta-cyclodextrins (CMGC) wereprepared by means of the reaction of chitosan microspheres and mono-(6-p-tosyl)- beta-cyclodextrins(beta-CD-OTs-6). beta-CD-OTs-6 were gained by the reaction of p-toluenesul-fonyl chloride (TsCl) andbeta-cyclodextrins (beta-CDs). Their structures were proved by Fourier transform infrared spectralanalysis (FT-IR), X ray powder diffraction analysis, and ^(13)C NMR; the configuration of CMGC wascharacterized by scanning electron micrograph (SEM) and transmittance electron micrograph (TEM). Theinclusion complex of CMGC with iodine was prepared and its inclusion ability was studied. Theexperimental results showed that some iodine was included with CMGC and formed a stable inclusion.The stable complex of CMGC and iodine (CMGC-1) shows good antibacterial effect.

Studies on Antibacterial QSAR of Diterpene Quinones from Sclvic Przewalskii Maxim

The antibacierial (staphylococcus aureus) activities of 23 diterpene quinones from the Salvia przewalskii Maxim, the artificial synthesis ones and that of the metabolism in pigs were examined in an effort to study the quantitative structure activity relationship with the Free-Wilson method. With the application of the multipiy regression, the Free-Wilson pattern was established by the dummy (indicator) variable of the structural fragments or substituents. The results showed: (1) The diketone moiety played the fundamental role in antibacterial activities, ortho-quinones was higher active than para-quinones. (2) The single bond existed between the C15 and the C16 at D-ring led to higher activity. (3) The saturation at the A-ring led to higher activity. (4) The components adjacent to nitrogen substituents at C15 led to higher activity. (5)The hydroxylation or dehydrogenation at A-ring led to less activity. The research results can provide the theoretical basis for developing a new antibacterial drug from the Salvia diterpene quinones.

Anti-microbial Effects In Vitro and In Vivo of Alstonia scholaris

Alstonia scholaris could be used as a traditional medicinal plant in China for the treatment of acute respiratory,which might be caused by respiratory tract infections.The investigation tested the anti-infective effects of total alkaloids extract(TA)from leaves of A.scholaris,and as a result,TA inhibited herpes simplex virus type 1(HSV-1),respiratory syncytial virus(RSV)and influenza A virus(H1N1)in vitro respectively.In addition,the survival days of mice were prolonged,and the lung weights and mortality of mice were decreased significantly,after oral administrated TA in H1N1 and beta-hemolytic streptococcus infectious models in vivo respectively.The finding supported partly the traditional usage of A.scholaris in the treatment of respiratory infections.

Synthesis and Application of Nanocomposite Reinforced with Decorated Multi Walled Carbon Nanotube with Luminescence Quantum Dots

Amidst the COVID-19 pandemic, environmental problems such as energy crisis, global warming, and contamination from pathogenic micro-organisms are still prevailed and strongly demanded progress in high-performance energy storing and anti-microbial materials. The nanocomposites are materials that have earned large interest owing to their promising applications for countering global issues related to sustainable energy and a flourishing environment. Here, polypyrrole coated hybrid nanocomposites of multi-walled carbon nanotube and cadmium sulfide quantum dots named MCP were synthesized using facile and low-cost in-situ oxidative polymerization method. Characterization techniques confirmed the synthesis. Electrochemical studies showed that the nanocomposite 1-MCP showed an impressively higher super capacitance behavior in comparison to f-MWCNT, 7-MCP and 5-MCP. The improved performance of the nanocomposites was attributed mainly to the good conductivity of carbon nanotubes and polypyrrole, high surface area, and stability of the carbon nanotubes and the high electrocatalytic activity of the cadmium sulfide quantum dots. Owing to the synergistic effect of MWCNT, CdS, and PPy the synthesized ternary nanocomposite also inhibited the growth and multiplication of tested bacteria such as S. aureus, and E. coli completely within 24 h. On the whole, the assimilated nanocomposite MCP opens promising aspects for the development of upcoming energy storage devices and as an antibacterial agent.

Carvacrol combined with NIR light-responsive nano-drug delivery system with specific anti-bacteria,anti-inflammation,and immunomodulation for periodontitis

Bacterial infection,biofilm formation,immune dysfunction are common triggers and aggravators in periodontitis,which render periodontal restoration challenging.Thus,a strategy with antibacterial,anti-inflammatory,immunoregulatory capacities has great promise in the clinical practice of periodontitis.Herein,carvacrol(CA)-based near-infrared(NIR)lightresponsive nano-drug delivery system is developed for the first time.The system consists of upconversion nanoparticles(UCNPs,which upconvert 808 nm NIR to blue light),mesoporous silica(mSiO_(2),the carrier channel),hydrophobic CA(blue light response properties).Under the irradiation of 808 nm NIR,owing to the synergy of CA and upconverted blue light,the UCNPs@mSiO_(2)-CA(UCMCs)exhibit the properties of specific anti-bacteria(including anaerobic bacteria),anti-inflammation,and immunomodulation.Notably,high-throughput sequencing results exhibit that many classic inflammatory immune-related signaling pathways,including the MAPK signaling pathway,tumor necrosis factor(TNF)signaling pathway,IL-17 signaling pathway,are enriched to remodel the immune microenvironment.Additionally,UCMCs with NIR irradiation accelerate periodontal restoration and serve as promising non-invasive management of periodontitis.Altogether,this study verifies the feasibility of herbal monomer combined with light-responsive in situ nano-drug delivery system and provides a more effective and reliable strategy for various potential applications of deep tissue diseases.

Researcher Urges Less Use of Anti-Bacteria Products

现在消毒柜,消毒水倍受许多有"洁癖"的人的青睐。同时,我们也经常听到悉心的父母对自己的孩子说:不要碰那个东西,上面有细菌。久而久之,人们一谈起细菌,就似乎是流行病、传染病如流感、疟疾、肝炎、肺结核等的代名词。现在研究表明,其实,细菌并没那么可怕。相反,有时候没有细菌的"真空"世界对你和你孩子的抗病能力的培养反而不利。物极必反,抗菌和抗生素的随意使用很可能招致"超级细菌"的滋生。

Phase-change composite filled natural nanotubes in hydrogel promote wound healing under photothermally triggered drug release

It is of great importance to treat a bacterial-infected wound by a smart dressing capable of delivering antibiotics in a smart manner without causing drug resistance.The construction of smart release nanocontainers responsive to near-infrared(NIR)laser irradiation in an on-demand and stepwise way is a promising strategy for avoiding the emergence of multidrug-resistant bacteria.Here,we develop a hydrogel composite made of alginate and nanotubes with an efficient NIR-triggered release of rifampicin and outstanding antibacterial ability.This composite hydrogel is prepared through co-encapsulating antibacterial drug(rifampicin),NIR-absorbing dye(indocyanine green),and phase-change materials(a eutectic mixture of fatty acids)into halloysite nanotubes,followed by incorporation into alginate hydrogels,allowing the in-situ gelation at room temperature and maintaining the integrity of drug-loaded nanotubes.Among them,the eutectic mixture with a melting point of 39℃ serves as the biocompatible phase-change material to facilitate the NIR-triggered drug release.The resultant phase-change material gated-nanotubes exhibit a prominent photothermal efficiency with multistep drug release under laser irradiation.In an in vitro assay,composite hydrogel provides good antibacterial potency against Staphylococcus aureus,one of the most prevalent microorganisms of dangerous gas gangrene.A bacterial-infected rat full-thickness wound model demonstrates that the NIR-responsive composite hydrogel inhibits the bacteria colonization and suppresses the inflammatory response caused by bacteria,promoting angiogenesis and collagen deposition to accelerate wound regeneration.The NIR-responsive composite hydrogel has a great po-tential as an antibacterial wound dressing functionalized with controlled multistep treatment of the infected sites.

Development of new Ti_(50)Zr_(25)Nb_(20)Cu_(5-x)Ag_(x)high-entropy alloys with excellent antibacterial property,osteo-conductivity and biocompatibility in vitro and in vivo

A new series of medical antibacterial high-entropy alloys(HEAs)with composition Ti 50 Zr 25 Nb 20 Cu 5-x Ag x(x=0 at.%,1 at.%,and 2.5 at.%)were developed by arc-melting the mixture of pure elements under a high-purity argon atmosphere.The cytotoxicity,osteo-conductivity,and antibacterial properties of these HEAs were systematically investigated in vitro,along with their in vivo biocompatibility and antibacte-rial properties.These HEAs,especially Ti_(50)Zr_(25)Nb_(20)Cu_(2.5)Ag_(2.5),showed better antibacterial ability against Staphylococcus aureus than Ti-6Al-4V,which has a nearly 99%antibacterial rate in vitro.Moreover,ion release and cytotoxicity tests showed that these HEAs had excellent biosafety,similar to or better than that of Ti-6Al-4V.Osteoblasts were used to evaluate the osteogenic activity of these HEAs,and good osteo-conductivity was observed in vitro.In a Sprague-Dawley rat infection model,Ti_(50)Zr_(25)Nb_(20)Cu_(2.5)Ag_(2.5)showed remarkable antibacterial properties compared to Ti-6Al-4V.The in vivo biocompatibility results showed that Ti_(50)Zr_(25)Nb_(20)Cu_(2.5)Ag_(2.5)did not increase biotoxicity compared to Ti-6Al-4V.The excellent bio-compatibility and antibacterial properties of the Ti-Zr-Nb-Cu-Ag HEAs are expected to enable the pre-vention of periprosthetic/peri-implant infections in the future.

Hydrogel-based artificial enzyme for combating bacteria and accelerating wound healing

Artificial enzymes have provided great antimicrobial activity to combat wound infection.However,the lack of tissue repair capability compromised their treatment effect.Therefore,development of novel artificial enzyme concurrently with the excellent antibacterial activity and the property of promoting wound healing are required.Here,we demonstrated the hydrogel-based artificial enzyme composed of copper and amino acids possessed intrinsic peroxidase-like catalytic activity,which could combat wound pathogen effectively and accelerate wound healing by stimulating angiogenesis and collagen deposition.Furthermore,the system possesses good biocompatibility for practical application.The synergic effect of the hydrogel-based artificial enzyme promises the system as a new paradigm in bacteria-infected wound healing therapy.

Near-infrared carbon nanodots for effective identification and inactivation of Gram-positive bacteria

An unacceptable increase in antibacterial resistance has arisen due to the abuse of multiple classes of broad-spectrum antibiotics.Therefore,it is significant to develop new antibacterial agents,especially those that can accurately identify and kill specific bacteria.Herein,we demonstrate a kind of perilla-derived carbon nanodots(CNDs),integrating intrinsic advantages of luminescence and photodynamic,providing the opportunity to accurately identify and kill specific bacteria.The CNDs have an exotic-doped andπ-conjugated core,vitalizing them near-infrared(NIR)absorption and emission properties with photoluminescence quantum yield of 21.1%;hydrophobic chains onto the surface of the CNDs make them to selectively stain Gram-positive bacteria by insertion into their membranes.Due to the strong absorption in NIR region,reactive oxygen species are in situ generated by the CNDs onto bacterial membranes under 660 nm irradiation,and 99.99%inactivation efficiency against Gram-positive bacteria within 5 min can be achieved.In vivo results demonstrate that the CNDs with photodynamic antibacterial property can eliminate the inflammation of the area affected by methicillin-resistant Staphylococcus aureus(MRSA),and enabling the wound to be cured quickly.

Mg-Fe LDH sealed PEO coating on magnesium for biodegradation control,antibacteria and osteogenesis

Attempt of developing bio-safety and functional layered double hydroxides(LDHs)modifed plasma electrolytic oxidation(PEO)coatings,has become a hotspot in the protection of magnesium(Mg)based biomedical implants.In the present work,Mg-Fe LDH flms with different Fe contents were fabricated on PEO coating via a novel two-step method:frstly,the Fe OOH flms were prepared by immersing PEO sample in Fe^(2+)-containing solution,and then Mg-Fe LDH flms were formed by transforming the Fe OOH flms via a hydrothermal treatment in water.The highly-oriented LDH nano-sheets could enhance the anti-corrosion performance of PEO coating,which was proved by the results of electrochemical test,hydrogen evolution and corroded morphology.PEO/Mg-Fe LDH coatings showed a low hemolysis rate(less5%)than PEO coating.In addition,PEO/Mg-Fe LDH coatings were more favorable for cell adhesion and proliferation than PEO coating.Moreover,PEO/Mg-Fe LDH coatings showed good photothermal conversion property,which demonstrated the excellent rapid antibacterial effect under NIR light.In vitro culture of rat bone marrow stem cell(r BMSC)suggested that cells cultured in the extract of PEO/Mg-Fe LDH coatings had a better osteogenic activity.In vivo subcutaneous implantation test revealed that PEO/Mg-Fe LDH coatings exhibited good anti-corrosion and histocompatibility.

Enzymatically-degradable hydrogel coatings on titanium for bacterial infection inhibition and enhanced soft tissue compatibility via a self-adaptive strategy

Ideal percutaneous titanium implants request both antibacterial ability and soft tissue compatibility.ZnO structure constructed on titanium has been widely proved to be helpful to combat pathogen contamination,but the biosafety of ZnO is always questioned.How to maintain the remarkable antibacterial ability of ZnO and efficiently reduce the corresponding toxicity is still challenging.Herein,a hybrid hydrogel coating was constructed on the fabricated ZnO structure of titanium,and the coating was proved to be enzymatically-degradable when bacteria exist.Then the antibacterial activity of ZnO was presented.When under the normal condition(no bacteria),the hydrogel coating was stable and tightly adhered to titanium.The toxicity of ZnO was reduced,and the viability of fibroblasts was largely improved.More importantly,the hydrogel coating provided a good buffer zone for cell ingrowth and soft tissue integration.The curbed Zn ion release was also proved to be useful to regulate fibroblast responses such as the expression of CTGF and COL-I.These results were also validated by in vivo studies.Therefore,this study proposed a valid self-adaptive strategy for ZnO improvement.Under different conditions,the sample could present different functions,and both the antibacterial ability and soft tissue compatibility were finely preserved.

Formation of a ZnO nanorods-patterned coating with strong bactericidal capability and quantitative evaluation of the contribution of nanorods-derived puncture and ROS-derived killing

To endow Ti-based orthopedic implants with strong bactericidal activity,a ZnO nanorods-patterned coating(namely ZNR)was fabricated on Ti utilizing a catalyst-and template-free method of micro-arc oxidation(MAO)and hydrothermal treatment(HT).The coating comprises an outer layer of ZnO nanorods and a partially crystallized inner layer with nanocrystalline TiO_(2) and Zn_(2)TiO_(4) embedded amorphous matrix containing Ti,O and Zn.During HT,Zn^(2+)ions contained in amorphous matrix of the as-MAOed layer migrate to surface and react with OHin hydrothermal solution to form ZnO nuclei growing in length at expense of the migrated Zn^(2+).ZNR exhibits intense bactericidal activity against the adhered and planktonic S.aureus in vitro and in vivo.The crucial contributors to kill the adhered bacteria are ZnO nanorods derived mechano-penetration and released reactive oxygen species(ROS).Within 30 min of S.aureus incubation,ROS is the predominant bactericidal contributor with quantitative contribution value of ~20%,which transforms into mechano-penetration with prolonging time to reach quantitative contribution value of ~96% at 24 h.In addition,the bactericidal contributor against the planktonic bacteria of ZNR is relied on the released Zn^(2+).This work discloses an in-depth bactericidal mechanism of ZnO nanorods.

A novel breathable flexible metallized fabric for wearable heating device with flame-retardant and antibacterial properties

Currently,there is an imperative demand for developing a novel flexible heater with high adhesion,breathability,and extreme condition resistance,such as ultra-high temperatures and even fire.Herein,a high-adhesion,flame-retardancy,and anti-bacteria copper nanoparticles networks/nylon 6 woven fabric(CNNs/NWF)wearable heater with a“sandwich-like”structure has been designed and fabricated based on phatic acid/aminopropyltriethoxysilane(PA/APTES)hybrid coating.On the one hand,the CNNs/NWF wearable heater exhibited superb electrothermal behavior working at a peak temperature of 208.8℃powered with 2.0 V,better than that of wearable heaters in the recently reported literature.On the other hand,the vertical burning test showed that the heater possesses splendid flame retardancy.Furthermore,the PA/APTES coating could deposit a nanoscale porous protective film on the surface of CNNs/NWF,which imparts the heater with relatively excellent oxidation resistance and breathability.In addition,the antibacterial efficiency against Escherichia coli(E.coli)and Staphylococcus aureus(S.aureus)still reached100%after 50 times of standard washing and being electrified at 2.0 V for 5 min,keeping humans away from the threat of bacterial infections.We think that the heater in this research could be extended to wearable heating devices.

The multifunctional wound dressing with core-shell structured fibers prepared by coaxial electrospinning

The non-woven wound dressing with core-shell structured fibers was prepared by coaxial electrospinning. The polycaprolactone （PCL） was electrospun as the fiber＇s core to provide mechanical strength whereas collagen was fabricated into the shell in order to utilize its good biocompatibility. Simultaneously, the silver nanoparticles （Ag- NPs） as anti-bacterial agent were loaded in the shell whereas the vitamin A palmitate （VA） as healing-promoting drug was encapsulated in the core. Resulting from the fiber＇s core- shell structure, the VA released from the core and Ag-NPs present in the shell can endow the dressing both heal-promoting and anti-bacteria ability simultaneously, which can greatly enhance the dressing＇s clinical therapeutic effect. The dressing can maintain high swelling ratio of 190% for 3 d indicating its potential application as wet dressing. Furthermore, the dressing＇s anti-bacteria ability against Staphylococcus aureus was proved by in vitro anti-bacteria test. The in vitro drug release test showed the sustainable release of VA within 72 h, while the cell attachment showed L929 cells can well attach on the dressing indicating its good biocompatibility. In conclusion, the fabricated nanofibrous dressing possesses multiple functions to benefit wound healing and shows promising potential for clinical application.

Eco-friendly bacteria-killing by nanorods through mechano-puncture with top selectivity

Nanorods can induce mechano-puncture of Staphylococcus aureus(S.aureus)that often impairs osseointegration of orthopedic implants,while the critical nanorod top sharpness able to puncture S.aureus and the predominant contributor between top sharpness and length to mechano-puncture activity remains elusive.Herein,we fabricated three kinds of Al2O3-wrapped nanorods patterned arrays with different lengths and top sharpness.The top-sharp nanorods have lengths of 469 and 884 nm and the shorter show a length identical to the top-flat nanorods.Driven by the equivalent adhesive force of S.aureus,the top-flat nanorods deform cell envelops,showing a bacteriostatic rate of 29%owing to proliferation-inhibited manner.The top-sharp nanorods puncture S.aureus,showing a bactericidal rate of 96%for the longer,and 98%for the shorter that simultaneously exhibits fair osseointegration in bacteria-infected rat tibias,identifying top sharpness as a predominate contributor to mechano-puncture activity.Based on finite-element simulation,such top-flat nanorod derives the maximum stress(Smax)of 5.65 MPa on cell wall,lower than its ultimate-tensile-strength(13 MPa);while such top-sharp and shorter nanorod derives Smax of 20.15 MPa to puncture cell envelop.Moreover,a critical top conical angle of 138◦is identified for nanorods able to puncture S.aureus.