Bone Endosteal Mimics Regulates Breast Cancer Development and Phenotype.

Bone is a frequent site for metastatic development in various cancer types, including breast cancer, with a grim prognosis due to the distinct bone environment. Despite considerable advances, our understanding of the underlying processes leading to bone metastasis progression remains elusive. Here, we applied a bioactive three-dimensional (3D) model capable of mimicking the endosteal bone microenvironment. MDA-MB-231 and MCF7 breast cancer cells were cultured on the scaffolds, and their behaviors and the effects of the biomaterial on the cells were examined over time. We demonstrated that close interactions between the cells and the biomaterial affect their proliferation rates and the expression of c-Myc, cyclin D, and KI67, leading to cell cycle arrest. Moreover, invasion assays revealed increased invasiveness within this microenvironment. Our findings suggest a dual role for endosteal mimicking signals, influencing cell fate and potentially acting as a double-edged sword, shuttling between cell cycle arrest and more active, aggressive states.

Safety of propofol-assisted deep extubation in the dental treatment of children-a retrospective, observational study.

PURPOSE: Awake extubation and deep extubation are commonly used anesthesia techniques. In this study, the safety of propofol-assisted deep extubation in the dental treatment of children was assessed. MATERIALS AND METHODS: Children with severe caries who received dental treatment under general anesthesia and deep extubation between January 2017 and June 2023 were included in this study. Data were collected on the following variables: details and time of anesthesia, perioperative vital signs, and incidence of postoperative complications. The incidence of laryngeal spasm (LS) was considered to be the primary observation indicator. RESULTS: The perioperative data obtained from 195 children undergoing dental treatment was reviewed. The median age was 4.2 years (range: 2.3 to 9.6 years), and the average duration of anesthesia was 2.56 h (range 1 to 4.5 h). During intubation with a videoscope, purulent mucus was found in the pharyngeal cavity of seven children (3.6%); LS occurred in five of them (2.6%), and one child developed a fever (T = 37.8 °C) after discharge. Five children (2.6%) experienced emergence agitation (EA) in the recovery room. Also, 13 children (6.7%) experienced epistaxis; 10 had a mild experience and three had a moderate experience. No cases of airway obstruction (AO) and hypoxemia were recorded. The time to open eyes (TOE) was 16.3 ± 7.2 min. The incidence rate of complications was 23/195 (11.8%). Emergency tracheal reintubation was not required. Patients with mild upper respiratory tract infections showed a significantly higher incidence of complications (P < 0.001). CONCLUSIONS: Propofol-assisted deep extubation is a suitable technique that can be used for pediatric patients who exhibited non-cooperation in the outpatient setting. Epistaxis represents the most frequently encountered complication. Preoperative upper respiratory tract infection significantly increases the risk of complications. The occurrence of EA was notably lower than reported in other studies.

Facet-dependent transformation and toxicity of nanoscale zinc oxide in the synthetic saliva.

The nanoscale zinc oxide (n-ZnO) was used in food packages due to its superior antibacterial activity, resulting in potential intake of n-ZnO through the digestive system, wherein n-ZnO interacted with saliva. In recent, facet engineering, a technique for controlling the exposed facets, was applied to n-ZnO, whereas risk of n-ZnO with specific exposed facets in saliva was ignored. ZnO nanoflakes (ZnO-0001) and nanoneedles (ZnO-1010) with the primary exposed facets of {0001} and {1010} respectively were prepared in this study, investigating stability and toxicity of ZnO-0001 and ZnO-1010 in synthetic saliva. Both ZnO-0001 and ZnO-1010 partially transformed into amorphous Zn3(PO4)2 within 1 hr in the saliva even containing orgnaic components, forming a ZnO-Zn3(PO4)2 core-shell structure. Nevertheless, ZnO-1010 relative to ZnO-0001 would likely transform into Zn3(PO4)2, being attributed to superior dissolution of {1010} facet due to its lower vacancy formation energy (1.15 eV) than {0001} facet (3.90 eV). The toxicity of n-ZnO to Caco-2 cells was also dependent on the primary exposed facet; ZnO-0001 caused cell toxicity through oxidative stress, whereas ZnO-1010 resulted in lower cells viability than ZnO-0001 through oxidative stress and membrane damage. Density functional theory calculations illustrated that ·O2- was formed and released on {1010} facet, yet O22- instead of ·O2- was generated on {0001} facet, leading to low oxidative stress from ZnO-0001. All findings demonstrated that stability and toxicity of n-ZnO were dependent on the primary exposed facet, improving our understanding of health risk of nanomaterials.

OsPEX1, an extensin-like protein, negatively regulates root growth in a gibberellin-mediated manner in rice.

Leucine-rich repeat extensins (LRXs) are required for plant growth and development through affecting cell growth and cell wall formation. LRX gene family can be classified into two categories: predominantly vegetative-expressed LRX and reproductive-expressed PEX. In contrast to the tissue specificity of Arabidopsis PEX genes in reproductive organs, rice OsPEX1 is also highly expressed in roots in addition to reproductive tissue. However, whether and how OsPEX1 affects root growth is unclear. Here, we found that overexpression of OsPEX1 retarded root growth by reducing cell elongation likely caused by an increase of lignin deposition, whereas knockdown of OsPEX1 had an opposite effect on root growth, indicating that OsPEX1 negatively regulated root growth in rice. Further investigation uncovered the existence of a feedback loop between OsPEX1 expression level and GA biosynthesis for proper root growth. This was supported by the facts that exogenous GA3 application downregulated transcript levels of OsPEX1 and lignin-related genes and rescued the root developmental defects of the OsPEX1 overexpression mutant, whereas OsPEX1 overexpression reduced GA level and the expression of GA biosynthesis genes. Moreover, OsPEX1 and GA showed antagonistic action on the lignin biosynthesis in root. OsPEX1 overexpression upregulated transcript levels of lignin-related genes, whereas exogenous GA3 application downregulated their expression. Taken together, this study reveals a possible molecular pathway of OsPEX1mediated regulation of root growth through coordinate modulation of lignin deposition via a negative feedback regulation between OsPEX1 expression and GA biosynthesis.

Long-circulating doxorubicin and Schizandrin A liposome with drug-resistant liver cancer activity: in vitro and in vivo evaluation.

Co-loading doxorubicin (DOX) and Schizandrin A (SchA) long-circulating liposome (SchA-DOX-Lip) have been confirmed to have good antitumor activity in vitro. However, in vivo pharmacodynamics, targeting, safety, and mechanism of action of SchA-DOX-Lip still need to be further verified. We investigated the tumor inhibition effect, targeting, safety evaluation, and regulation of tumor apoptosis-related proteins of the SchA-DOX-Lip. MTT assay was used to investigate the inhibitory effect of SchA-DOX-Lip on CBRH7919 cells. The drug uptake of CBRH7919 cells was observed by inverted fluorescence microscope. The tumor-bearing nude mice models of CBRH7919 were established, and the anti-tumor effect of SchA-DOX-Lip in vivo was evaluated by tumor biological observation, H&E staining, and TUNEL staining. The distribution and targeting of SchA-DOX-Lip in nude mice models were investigated by small animal imaging and tissue distribution experiment of CBRH7919. The biosafety of SchA-DOX-Lip was evaluated by blood routine parameters, biochemical indexes, and H&E staining. The expression of tumor-associated apoptotic proteins (Bcl-2, Bax, and Caspase-3) was detected by immunohistochemistry anvd western blotting. The results showed that SchA-DOX-Lip had cytotoxicity to CBRH7919 cells which effectively inhibited the proliferation of CBRH7919 cells, improved the uptake of drugs by CBRH7919 cells and the targeting effect of drugs on tumor site. H&E staining and biochemical detection results showed that SchA-DOX-Lip had high biosafety and did not cause serious damage to normal tissues. Western-blotting and TUNEL staining results showed that SchA-DOX-Lip could improve the regulatory effect of drugs on tumor apoptosis proteins. It was demonstrated that SchA-DOX-Lip had high safety and strong tumor inhibition effects, providing a new method for the clinical treatment of hepatocellular carcinoma (HCC).

Thermosensitive Polymer Conjugated Prodrug-Activating Enzyme with Enhanced Tumor Retention and Antitumor Efficacy.

Enzyme-activated prodrug therapy has emerged as an effective strategy for cancer therapy. However, the inefficient delivery of prodrug-activating enzymes into tumor tissues leads to unsatisfactory antitumor efficacy and undesirable toxicity to normal tissues. Herein, we report in situ growth of a thermosensitive polymer of poly(diethylene glycol) methyl ether methacrylate (PDEGMA) from horseradish peroxidase (HRP) to yield a HRP-PDEGMA conjugate with well-retained activity as compared to HRP. The conjugate shows a sharp phase transition behavior with a lower critical solution temperature of 23 °C. The conjugate catalyzes the conversion of non-cytotoxic indole-3-acetic acid (IAA) into cytotoxic species for killing tumor cells. Notably, the PDEGMA conjugation not only increases the stability and cellular uptake of HRP but also prolongs the tumor retention time of HRP upon intratumoral injection. As a result, in mice bearing melanoma, the conjugate inhibits the growth of melanoma much more efficiently than HRP. These results demonstrate that the thermosensitive polymer conjugation of an enzyme is an effective strategy that can enhance the antitumor efficacy of an enzyme-activated prodrug.

Three-dimensional printed polylactic acid and hydroxyapatite composite scaffold with urine-derived stem cells as a treatment for bone defects.

Bone defects still pose various challenges in osteology. As one treatment method for bone defects, tissue engineering requires biomaterials with good biocompatibility and stem cells with good differentiation. This study aimed to fabricate a 3D-printed polylactic acid and hydroxyapatite (PLA/HA) composite scaffold with urine-derived stem cells (USCs) to study its therapeutic effect in a rat model of skull defects. USCs were isolated and extracted from the urine of healthy adult males and inoculated onto PLA/HA and PLA scaffolds fabricated by 3D printing technology. A total of 36 skull defect models in eighteen Sprague-Dawley rats were randomly divided into a control group (no treatment of the defects), PLA group (treated with PLA scaffolds with USCs), and PLA/HA group (treated with PLA/HA scaffolds with USCs). The therapeutic efficacy was evaluated by real-time PCR, microcomputed tomography (micro-CT), and immunohistochemistry at 4, 8, and 12 weeks. We found that the PLA/HA scaffold loaded with USCs effectively promoted new bone regeneration in the defect area. CT images showed that in the PLA/HA group, the defect area was almost entirely covered by newly formed bone (coverage of 96.7 ± 1.6%), and the coverage was greater than that in the PLA group (coverage of 74.6 ± 1.9%) at 12 weeks. Histology and immunohistochemical staining showed the highest new bone formation on the PLA/HA scaffolds containing USCs in the defect site at 12 weeks. These findings demonstrate the broad application prospects of PLA/HA scaffolds with USCs in bone tissue engineering. Graphical abstract.

Cross-habitat distribution pattern of Bacillus communities and their capacities of producing industrial hydrolytic enzymes in Paracel Islands: Habitat-dependent differential contributions of the environment.

Bacillus as a predominant genus of enzyme-producing bacteria presents desirable features to fulfill the vast demand of specific industries, whereas the knowledge of the Bacillus communities and their capacities of producing industrial hydrolytic enzymes across the microhabitats of the Paracel Islands is limited. Herein, a total of 193 culturable Bacillus strains belonging to 19 species were isolated across the microhabitats of seawater, sediment, coral and seagrass, covering 39 stations of the Paracel Islands. Each microhabitat displayed its unique species, while the species of Bacillus paramycoides besides being the dominant species with an abundance of 54.94% also was the only species shared by all microhabitats of the Paracel Islands. Of the Bacillus communities, 97.41% of the isolates exhibited the capacity of producing one-or-more types of enzymes with comparatively higher and broader ranges of enzyme activities, including 163 protease-, 27 cellulase-, 118 alginate lyase-, 140 K-carrageenase- and 158 agarose-producing strains. By the correlation analyses of "Bacillus-environmental factors" and "Enzyme-producing Bacillus-environmental factors", the cross-habitat distribution and enzyme-producing capacity pattern of the Bacillus communities were strongly driven by habitat type, and the environmental factors made habitat-dependent differential contributions to that in the Paracel Islands. It's worth noting that the cellulase-producing strain wasn't detected in seagrass due to its survival strategy to prevent cellulose degradation by inhibiting cellulase-producing bacteria, while coral contained more stable microbial metabolic functions to protect against environmental fluctuations. These findings besides providing large quantities of promising enzyme-producing candidates for specific industrial desires, also facilitate the development and utilization of marine microbial resources and the environmental policy- and/or law-making according to environmental features across the microhabitats of the Paracel Islands.

Drug release evaluation of Paclitaxel/Poly-L-Lactic acid nanoparticles based on a microfluidic chip.

Paclitaxel is a commonly used drug in the medical field because of its strong anticancer effect. However, it may produce relatively severe side effects (i.e., allergic reactions). A major characteristic of paclitaxel is low solubility in water. Special solvents are used for dissolving paclitaxel and preparing the paclitaxel drugs, while the solvents themselves will cause certain effects. Polyoxyethylene castor oil, for example, can cause severe allergic reactions in some people, and the clinical use is limited. In this study, we developed a new Paclitaxel/Poly-L-Lactic Acid (PLLA) nanoparticle drug, which is greatly soluble in water, and carried out in vitro drug sustained release research on it and the original paclitaxel drug. However, because the traditional polymer drug carrier usually uses dialysis bag and thermostatic oscillation system to measure the drug release degree in vitro, the results obtained are greatly different from the actual drug release results in human body. Therefore, this paper adopts the microfluidic chip we previously developed to mimic the human blood vessels microenvironment to study the sustained-release of Paclitaxel/PLLA nanoparticles to make the results closer to the release value in human body. The experimental results showed that compared with the original paclitaxel drug, Paclitaxel/PLLA nanoparticles have a long-sustained release time and a slow drug release, realizing the sustained low-dose release of paclitaxel, a cell cycle-specific anticancer drug, and provided certain reference significance and theoretical basis for the research and development of anticancer drugs.

Studying endothelial cell shedding and orientation using adaptive perfusion-culture in a microfluidic vascular chip.

Most tissue-engineered blood vessels are endothelialized by static cultures in vitro. However, it has not been clear whether endothelial cell-shedding and local damage may occur in an endothelial layer formed by static cultures under the effect of blood flow shear postimplantation. In this study, we report a bionic and cost-effective vascular chip platform, and proved that a static culture of endothelialized tissue-engineered blood vessels had the problem of a large number of endothelial cells falling off under the condition imitating the human arterial blood flow, and we addressed this challenge by regulating the flow field in a vascular chip. Electrospun membranes made of highly oriented or randomly distributed poly(ε-caprolactone) fibers were used as the vascular scaffolds, on which endothelial cells proliferated well and eventually formed dense intima layers. We noted that the monolayers gradually adapted to the artery-like microenvironment through the regulation of chip flow field, which also revealed improved cellular orientations. In conclusion, we have proposed a vascular chip with adaptive flow patterns to gradually accommodate the statically cultured vascular endothelia to the shear environment of arterial flow field and enhanced the orientation of the endothelial cells. This strategy may find numerous potential applications such as screening of vascular engineering biomaterials and maturation parameters, studying of vascular biology and pathology, and construction of vessel-on-a-chip models for drug analysis, among others.

A Novel Sirolimus-eluting Biodegradable Magnesium-based Alloy Scaffold: Six-month Results In Porcine Peripheral Arteries.

PURPOSE: Magnesium-based alloy scaffold is a promising biodegradable stent due to its intrinsic mechanical performance and biocompatibility. Based on our preliminary experiments, we designed a novel sirolimus-eluting magnesium-based alloy scaffold. This work aimed to assess its safety and degradation performance in vivo. METHODS: The scaffolds were implanted in the lower limb arteries of Bama mini-pigs. Safety was defined as no immediate thrombosis or >30% residual stenosis, which was assessed with optical coherence tomography and digital subtraction angiography. Blood biochemical analyses were performed to evaluate hepatorenal toxicity. The degradation process of the scaffolds, the endothelialization, and lumen loss of the stented-vessels were detected with scanning electron microscopy, immunohistochemical, hematoxylin-eosin staining and optical coherence tomography. RESULTS: Twenty-four scaffolds were successfully implanted in six pigs with no signs of immediate thrombosis or >30% residual stenosis. The scaffolds were covered by endothelium at one month and absolutely resorbed at six months post implantation. Blood analysis showed that the hepatorenal function except for alanine aminotransferase and γ-glutamyl transpeptidase was normal. Obvious intimal hyperplasia and lumen loss were found in the stented vessels at three months, while the diameters and inner lumen areas of stented segments had increased significantly at six months (p.

The exploration of neuraminidase inhibitory activity on Fallopia denticulata, an ethnic herb in China.

This study was designed to explore the bioactive ingredients in the extracts of Fallopia denticulata (C.C. Huang) Holub, a medicinal plant grown in China, which exhibits the best neuraminidase (NA) inhibition activity. Three fractions of ethyl acetate, ethanol, and water were tested on NA inhibition assay, and the best one was conducted by ultra-performance liquid chromatography-time-of-flight mass spectrometry in the negative and positive modes to analyze the metabolic components. The results revealed the identification of the following 21 compounds: 3 organic acids, 11 flavonoids, 1 coumarin, and 6 others, such as ß-daucosterol, gallic acid, and syringic acid, of which 12 compounds were discovered for the first time in F. denticulata. In addition, we used the molecular docking technique to support the anti-NA activity of each compound in the best extract. The results confirmed that the two better bioactive compounds were (-)-epicatechin gallate and (+)-catechin. Therefore, F. denticulata could be used as a potential material for new anti-influenza drugs.

Rice OsPEX1, an extensin-like protein, affects lignin biosynthesis and plant growth.

KEY MESSAGE: Rice leucine-rich repeat extensin-like protein OsPEX1 mediates the intersection of lignin deposition and plant growth. Lignin, a major structural component of secondary cell wall, is essential for normal plant growth and development. However, the molecular and genetic regulation of lignin biosynthesis is not fully understood in rice. Here we report the identification and characterization of a rice semi-dominant dwarf mutant (pex1) with stiff culm. Molecular and genetic analyses revealed that the pex1 phenotype was caused by ectopic expression of a leucine-rich repeat extension-like gene, OsPEX1. Interestingly, the pex1 mutant showed significantly higher lignin content and increased expression levels of lignin-related genes compared with wild type plants. Conversely, OsPEX1-suppresssed transgenics displayed low lignin content and reduced transcriptional abundance of genes associated with lignin biosynthesis, indicating that the OsPEX1 mediates lignin biosynthesis and/or deposition in rice. When OsPEX1 was ectopically expressed in rice cultivars with tall stature that lacks the allele of semi-dwarf 1, well-known green revolution gene, the resulting transgenic plants displayed reduced height and enhanced lodging resistance. Our study uncovers a causative effect between the expression of OsPEX1 and lignin deposition. Lastly, we demonstrated that modulating OsPEX1 expression could provide a tool for improving rice lodging resistance.

A 3.0-Angstrom Resolution Cryo-Electron Microscopy Structure and Antigenic Sites of Coxsackievirus A6-Like Particles.

Coxsackievirus A6 (CVA6) has recently emerged as one of the predominant causative agents of hand, foot, and mouth disease (HFMD). The structure of the CVA6 mature viral particle has not been solved thus far. Our previous work shows that recombinant virus-like particles (VLPs) of CVA6 represent a promising CVA6 vaccine candidate. Here, we report the first cryo-electron microscopy (cryo-EM) structure of the CVA6 VLP at 3.0-Å resolution. The CVA6 VLP exhibits the characteristic features of enteroviruses but presents an open channel at the 2-fold axis and an empty, collapsed VP1 pocket, which is broadly similar to the structures of the enterovirus 71 (EV71) VLP and coxsackievirus A16 (CVA16) 135S expanded particle, indicating that the CVA6 VLP is in an expanded conformation. Structural comparisons reveal that two common salt bridges within protomers are maintained in the CVA6 VLP and other viruses of the Enterovirus genus, implying that these salt bridges may play a critical role in enteroviral protomer assembly. However, there are apparent structural differences among the CVA6 VLP, EV71 VLP, and CVA16 135S particle in the surface-exposed loops and C termini of subunit proteins, which are often antigenic sites for enteroviruses. By immunological assays, we identified two CVA6-specific linear B-cell epitopes (designated P42 and P59) located at the GH loop and the C-terminal region of VP1, respectively, in agreement with the structure-based prediction of antigenic sites. Our findings elucidate the structural basis and important antigenic sites of the CVA6 VLP as a strong vaccine candidate and also provide insight into enteroviral protomer assembly.IMPORTANCE Coxsackievirus A6 (CVA6) is becoming one of the major pathogens causing hand, foot, and mouth disease (HFMD), leading to significant morbidity and mortality in children and adults. However, no vaccine is currently available to prevent CVA6 infection. Our previous work shows that recombinant virus-like particles (VLPs) of CVA6 are a promising CVA6 vaccine candidate. Here, we present a 3.0-Å structure of the CVA6 VLP determined by cryo-electron microscopy. The overall architecture of the CVA6 VLP is similar to those of the expanded structures of enterovirus 71 (EV71) and coxsackievirus A16 (CVA16), but careful structural comparisons reveal significant differences in the surface-exposed loops and C termini of each capsid protein of these particles. In addition, we identified two CVA6-specific linear B-cell epitopes and mapped them to the GH loop and the C-terminal region of VP1, respectively. Collectively, our findings provide a structural basis and important antigenic information for CVA6 VLP vaccine development.

Structure, Immunogenicity, and Protective Mechanism of an Engineered Enterovirus 71-Like Particle Vaccine Mimicking 80S Empty Capsid.

Enterovirus 71 (EV71) is the major causative agent of severe hand, foot, and mouth disease, which affects millions of young children in the Asia-Pacific region annually. In this study, we engineered a novel EV71 virus-like particle (VLP) that lacks VP4 (therefore designated VLPΔVP4) and investigated its structure, antigenicity, and vaccine potential. The cryo-electron microscopy (cryo-EM) structure of VLPΔVP4 was reconstructed to 3.71-Å resolution. Results from structural and biochemical analyses revealed that VLPΔVP4 resembles the end product of the viral uncoating process, the 80S empty capsid. VLPΔVP4 is able to elicit high-titer neutralizing antibodies and to fully protect mice against lethal viral challenge. Mechanistic studies showed that, at the cellular level, the anti-VLPΔVP4 sera exert neutralization effects at both pre- and postattachment stages by inhibiting both virus attachment and internalization, and at the molecular level, the antisera can block multiple interactions between EV71 and its key receptors. Our study gives a better understanding of EV71 capsid assembly and provides important information for the design and development of new-generation vaccines for EV71, and perhaps for other enteroviruses, as well.IMPORTANCE Enterovirus 71 (EV71) infection may lead to severe hand, foot, and mouth disease, with significant morbidity and mortality. Knowledge regarding EV71 particle assembly remains limited. Here, we report the generation and characterization of a novel EV71 virus-like particle that lacks the VP4 capsid subunit protein. This particle, termed VLPΔVP4, structurally mimics the 80S empty capsid, which is the end stage of EV71 uncoating. We further show that VLPΔVP4 exhibits desirable immunogenicity and protective efficacy in proof-of-concept studies. In addition, the inhibitory mechanisms of the VLPΔVP4-induced antibodies are unraveled at both the cellular and molecular levels. Our work provides the first evidence of picornaviral particle assembly in the complete absence of VP4 and identifies VLPΔVP4 as an improved EV71 vaccine candidate with desirable traits. These findings not only enhance our understanding of particle assembly and uncoating of picornaviruses, but also provide important information for structure-guided vaccine design for EV71 and other enteroviruses.

Antibiofouling Zwitterionic Gradational Membranes with Moisture Retention Capability and Sustained Antimicrobial Property for Chronic Wound Infection and Skin Regeneration.

Nonadherent wound dressings with moisture management and long-lasting antibacterial properties have great significance for wound healing clinically. Herein, a novel multicomponent zwitterionic gradational membrane is fabricated by a co-electrospinning method to realize low biofouling and favorable moisture control as well as long-acting antibacterial properties during the chronic wound-healing process. The obtained membrane possesses excellent anti-biofouling performance that effectively resists protein, bacteria, and cell adhesion according to in vitro antifouling evaluation. Furthermore, the gradational co-electrospinning method grants the composite membrane with moisture retention capability which could effectively absorb wound exudate and maintain a moisture healing environment. Additionally, in vivo and in vitro antibacterial investigations reflect that the composite membrane has excellent long-acting antibacterial property. Moreover, in vivo wound healing assessment confirms that the prepared membrane significantly reduces the complete wound healing time than commercial wound dressing. These results highlight such a zwitterionic gradational membrane as an advanced wound dressing to meet the various requirements for chronic wound infection and skin tissue regeneration in clinical applications.

Expression of the VP1 protein of FMDV integrated chromosomally with mutant Listeria monocytogenes strain induced both humoral and cellular immune responses.

Live vector-based vaccine is a modern approach to overcome the drawbacks of inactivated foot-and-mouth disease (FMD) vaccines such as improper inactivation during manufacture. Listeria monocytogenes (LM), an intracellular microorganism with immune-stimulatory properties, is appropriate to be utilized as a live bacterial vaccine vector. FMDV-VP1 protein has the capability to induce both cellular and humoral immune responses since it is considered the most immunogenic part of FMDV capsid and has the most of antigenic sites for viral neutralization. The codon-optimized vp1 gene was ligated to the integrative pCW702 plasmid to construct the target cassette. The antigen cassette was integrated successfully into the chromosome of mutant LM strain via homologous recombination for more stability to generate a candidate vaccine strain LM△actAplcB-vp1. Safety evaluation of recombinant LM△actAplcB-vp1 revealed it could be eliminated from the internal organs within 3 days as a safe candidate vaccine. Mice groups were immunized I.V. twice with the recombinant LM△actAplcB-vp1 at an interval of 2 weeks. Antigen-specific IgG antibodies and the level of CD4+- and CD8+-specific secreted cytokines were estimated to evaluate the immunogenicity of the candidate vaccine. The rapid onset immune response was detected, strong IgG humoral immune response within 14 days post immunization and augmented again after the booster dose. Cellular immunity data after 9 days post the prime dose indicated elevation in CD4+ and CD8+ secreted cytokine level with another elevation after the booster dose. This is the first report to explain the ability of attenuated mutant LM to be a promising live vector for FMDV vaccine.

Study on the Mechanical Properties and Strengthening Mechanism of Interface-Modified Carbon Fiber Mesh Reinforced Cement-Based Composites with SCA&HMC.

Carbon fiber mesh reinforced cement-based composites (CMCCs) have received extensive attention in the field of engineering repair and structural reinforcement due to their outstanding properties such as two-way force, rust prevention, high specific strength, and low base surface requirements. However, the development of this material has been slowed down to some extent due to the poor interfacial bonding between the carbon fiber mesh and the cement matrix. In this paper, a novel fabrication strategy was proposed in which the carbon fiber mesh was modified with epoxy resin and silane coupling agent (SCA) to increase its surface chemical activity. Meanwhile, the hydroxymethyl cellulose (HMC) was also filled into the concrete matrix to improve the mechanical strength of the matrix as well as the load transfer behaviors between the mortar and carbon fiber (CF) mesh. The potential to employ SCA and HMC was evaluated for the making of CMCCs via the above methods. The results showed that the longitudinal shear strength of composites with SCA and SCA&HMC increased by 26.6% and 56.1% compared to those of CF with epoxy resin (EP) reinforced composites, respectively. The flexural strength of composite with SCA&HMC increases by 147.6% compared to I-(F) without CF. The novel II-HCM&CF/EP-SCA composites with excellent performance are promised to be applied in practical uses.

The microfabrication of mold for polymer microfluidic devices with Zr-based metallic glass.

Polymer microfluidic devices are used for many purposes such as microarrays and biochips. The key tool for manufacturing these chips in bulk is an appropriate mold. However, the popular material for making molds is nickel or nickel alloys, which have low stiffness and wear out easily. Zr-based metallic glass is a promising material for micro- or nanomolds because it has good mechanical properties and can be easily formed with high precision. In this paper, Zr-based metallic glass is proposed for use as micromold insert to make poly-(methyl methacrylate) (PMMA) microfluidic devices. Our experiments show that they have good feature integrity and replication quality. Microchannels we fabricated using these replicas did not leak and had good flow performance. Zr-based metallic glass can greatly ease the manufacture of plastic microfluidic devices for research and commercial applications.