Construction and evaluation of co-electrospun poly (butylene succinate)/gelatin materials as potential vascular grafts

In this study,a series of poly(butylene succinate)(PBSU)/gelatin composites were prepared by electrospinning.The morphology,physicochemical analysis,biomechanical properties,biocompatibility,and biodegradability of the materials were evaluated.The results showed that the ultimate tensile stress of the vascular PBSU/gelatin grafts at(95/5),(90/10),(85/15),and(80/20)was(4.17±0.54)MPa,(3.81±0.44)MPa,2.94±0.69 MPa and 2.11±0.72 MPa respectively,and the burst pressure was(282.7±22.3)kPa,(295.3±3.9)kPa,(306.8±13.9)kPa and(307.6±9.0)kPa respectively,which met the requirements of tissue-engineered blood vessels.Furthermore,the addition of gelatin improved the hydrophilicity and degradation properties of PBSU,thus enhancing cell adhesion and promoting the inward growth of vascular smooth muscle cells.In summary,the research in this paper provides a useful reference for the preparation and optimization of vascular scaffolds.

APPLICATION OF CHITOSAN-BASED BIOMATERIALS IN BIOARTIFICIAL LIVE

Bioart,ficial liver support system （BALS） has the potential to provide temporary support for patients with fulminant hepatic failure and consist of viable hepatocytes and scaffolding materials for hepatocytes attachment. Various scaffolding materials are used in BALS, including chitosan, which is easily obtained by deacetylation of chitin and widely applied in biomedical applications. In this paper, we introduce and discuses chitosan-based biomaterials for BALS application.

Apigenin ameliorates imiquimod-induced psoriasis in C57BL/6J mice by inactivating STAT3 and NF-κB

Psoriasis is a chronic autoimmune disease featured by patches on the skin.It is caused by malfunction of immune cells and keratinocytes with inflammation as one of its key features.Apigenin(API)is a natural flavonoid with anti-inflammatory and immunoregulatory properties.Therefore,we speculated that API can ameliorate psoriasis,and determined its effect on the development of psoriasis by using imiquimod(IMQ)-induced psoriasis mouse model.Our results showed that API attenuated IMQ-induced phenotypic changes,such as erythema,scaling and epidermal thickening,and improved splenic hyperplasia.Abnormal differentiation of immune cells was restored in API-treated mice.Mechanistically,we revealed that API is a key regulator of signal transducer activator of transcription 3(STAT3).API regulated immune responses by reducing interleukin-23(IL-23)/STAT3/IL-17A axis.Moreover,it suppressed IMQ-caused cell hyperproliferation by inactivating STAT3 through regulation of extracellular signal-regulated kinase 1/2 and nuclear factor-κB(NF-κB)pathway.Furthermore,API reduced expression of inflammatory cytokines through inactivation of NF-κB.Taken together,our study demonstrates that API can ameliorate psoriasis and may be considered as a strategy for psoriasis treatment.

A novel flexible nerve guidance conduit promotes nerve regeneration while providing excellent mechanical properties

Autografting is the gold standard for surgical repair of nerve defects>5 mm in length;however,autografting is associated with potential complications at the nerve donor site.As an alternative,nerve guidance conduits may be used.The ideal conduit should be flexible,resistant to kinks and lumen collapse,and provide physical cues to guide nerve regeneration.We designed a novel flexible conduit using electrospinning technology to create fibers on the innermost surface of the nerve guidance conduit and employed melt spinning to align them.Subsequently,we prepared disordered electrospun fibers outside the aligned fibers and helical melt-spun fibers on the outer wall of the electrospun fiber lumen.The presence of aligned fibers on the inner surface can promote the extension of nerve cells along the fibers.The helical melt-spun fibers on the outer surface can enhance resistance to kinking and compression and provide stability.Our novel conduit promoted nerve regeneration and functional recovery in a rat sciatic nerve defect model,suggesting that it has potential for clinical use in human nerve injuries.

Biodegradation of phenol by free and immobilized Acinetobacter sp.strain PD12

A new phenol-degrading bacterium with high biodegradation activity and high tolerance of phenol, strain PD 12, was isolated from the activated sludge of Tianjin Jizhuangzi Wastewater Treatment Facility in China. This strain was capable of removing 500 mg phenol/L in liquid minimal medium by 99.6% within 9 h and metabolizing phenol at concentrations up to 1100 mg/L. DNA sequencing and homologous analysis of 16S rRNA gene identified PD12 to be an Acinetobacter sp. Polyvinyl alcohol （PVA） was used as a gel matrix to immobilize Acinetobacter sp. strain PDI2 by repeated freezing and thawing. The factors affecting phenol degradation of immobilized cells were investigated, and the results showed that the immobilized cells could tolerate a high phenol level and protected the bacteria against changes in temperature and pH. Storage stability and reusability tests revealed that the phenol degradation functions of immobilized cells were stable after reuse for 50 times or storing at 4℃ for 50 d. These results indicate that immobilized Acinetobacter sp. strain PD 12 possesses a good application potential in the treatment of phenol-containing wastewater.

Mechanical Properties and Degradability of Electrospun PCL/PLGA Blended Scaffolds as Vascular Grafts

In our study, the mechanical properties and degradability of vascular grafts made from poly(ε-caprolactone)(PCL) and poly(lactic-co-glycolic acid)(PLGA) at different ratios were investigated. The results showed that the electrospun PCL/PLGA grafts possess good mechanical properties and biodegradability. The tensile and burst strength of the scaffolds met the demands of vascular grafts. In vitro degradation tests indicated that the degradation rate of the materials increased with the percentage of PLGA, and in vivo tests showed that increasing the amount of PLGA is an effective way to promote cell infiltration. Particularly, the electrospun PCL/PLGA blended scaffold with 10% PLGA exhibited a balance of mechanical and degradation properties, making it a promising tissue engineering material for vascular grafts.

Detection and quantification of enteroviruses in coastal seawaters from Bohai Bay,Tianjin,China

An 8-month survey was conducted to detect and quantify enteroviruses in Tianjin coastal seawaters of Bohai Bay to assess coastal water quality. Ten water samples were collected from Bohai Bay for the detection and quantification of enteroviruses by conventional reverse transcription polymerase chain reaction （RT-PCR） and SYBR Green real-time quantitative RT-PCR （qRT-PCR）. Total viral nucleic acid was extracted from 500 mL of seawater samples concentrated by Centricon plus-70 centrifugal filter devices. The viral recovery rate was 29.1% based on viral seeding study. The centrifugal ultrafiltration method applied is effective for viral recovery from small volume of polluted water, which may have broader applications to monitoring human virus in aquatic environment. Our results indicated that there was a severe viral contamination in seawater of Bohai Bay. Enteroviruses were detected at concentrations ranging from 1.7 × 10^6 to 6.3 × 10^7 copies/L by qRT-PCR. Sequencing analyses identified that all of the twenty clones as poliovirus type 2. This is the first quantitative report of human viruses in coastal waters of a metropolitan city in China. This study emphasized the importance for the local and central governmertts to monitor and assess the water quality.

Computer Aided Study of Mechanism of Immunoadsorbent for Myasthenia Gravis

Myasthenia Gravis (MG) is an organ specific autoimmune disease mediated by autoantibodies (AChR Ab) against the acetylcholine receptor (AChR). Literature reported that the AChR Ab can be removed by absorbent linked with tryptophan. It was studied in detail in our lab. With the aid of computer, we docked some ligands into AChR Ab, and the results from scores of docking under different generations showed that there was no specific binding between tryptophan and scFv fragment just as the binding between antigen-antibody. The interaction between Trp and immunoglobulin was a broad-spectrum binding.

Molecular basis of the first cell fate determination in mouse embryogenesis

Through proliferation and differentiation, a single cell, the zygote, can give rise to a complex organism composed of many types of cells. Up to the eight-cell embryo stage, the blastomeres are morphologically identical and distributed symmetrically in the mammalian embryo. Functionally, in some species, they are all totipotent. However, due to the compaction of blastomeres and the asymmetrical cell division at the late phase of the eight-cell embryo, the blastomeres of the morula are no longer identical. During the transition from morula to blastocyst, blastomeres differentiate, resulting in the first cell fate decision in embryogenesis, namely, the segregation of the inner cell mass and the tropheetoderm. In this review, we will discuss the regulatory mechanisms essential for the cell fate choice during blastocyst development, including transcriptional regulation, epigenetic regulation, mieroRNAs, and signal transduction.

A Strategy to Optimize the Oligo-Probes for Microarray-based Detection of Viruses

DNA microarrays have been acknowledged to represent a promising approach for the detection of viral pathogens. However, the probes designed for current arrays could cover only part of the given viral variants, that could result in false-negative or ambiguous data. If all the variants are to be covered, the requirement for more probes would render much higher spot density and thus higher cost of the arrays. Here we have developed a new strategy for oligonucleotide probe design. Using type I human immunodeficiency virus (HIV-1) tat gene as an example, we designed the array probes and validated the optimized parameters in silico. Results show that the oligo number is significantly reduced comparing with the existing methods, while specificity and hybridization efficiency remain intact. The adoption of this method in reducing the oligo numbers could increase the detection capacity for DNA microarrays, and would significantly lower the manufacturing cost for making array chips.

Perspectives in application of biosensors for the modernization of traditional Chinese medicine

Biosensor is an instrument which is sensitive to biological material and converts its concentration into electrical signals.Organisms such as enzymes, antibodies, tissues, cells and so on can selectively identify specific substances. Thesemolecular recognition functions can be combined with the target, such as the binding of antibodies and antigens, and thebinding of enzymes to the substrate through the recognition process. Biosensor has the advantages of high specificity,high sensitivity, fast reaction speed, low cost and easy operation. It has wide application prospect in food, pharmacy,chemical industry, clinical examination, biomedicine, environmental monitoring and so on, especially as a newtechnology means, in the field of modern herbal medicine research influence. Studies have demonstrated that thebiosensing technology has been applied to, traditional Chinese medicine （TCM） targets, isolation and purification ofTCM, the mechanism of TCM, quality control of TCM, the active ingredients detection of TCM and other basicresearches. Biosensor technology has made an important contribution to the research of modern herbal medicine, and hasbecome a Hot-spot in future research.

ISOLATION AND PURIFICATION OF ALKALOIDS FROM PLUMULA NELUMBINIS BY DOUBLE-COLUMN ADSORPTION CHROMOTOGRAPHY

The performance of adsorption and separation for liensinine, isoliensinine and neferine was studied by double-column adsorption chromatography using macroporous adsorption and cation exchange resins. The alkaloid extract with 49.2% total contents by mass representing 10.6% liensinine, 10.6% isoliensinine and 28.0% neferine respectively was prepared by D72 cation exchange resins, in which most of the impurities were water-soluble alkaloids. Furthermore,the alkaloid extract with 82.6% total contents by mass containing 33.1%, 15.0% and 34.5% of the three adsorbates respectively was prepared by double-column adsorption chromatography using AKS-W macroporous adsorption and D72 cation exchange resins. As a result, the content of single and total alkaloids has been greatly increased by the double-column adsorption chromatography.

THERMAL PROPERTY, MISCIBILITY AND CRYSTALLIZATION BEHAVIOR OF POLY(3-HYDROXYBUTYRATE-co-3-YDROXYHEXANOATE) AND POLY(BUTYLENE SUCCINATE-ADIPATE) (PHBHHX/PBSA) BLENDS

Blends of poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) (PHBHHx) and poly(butylene succinate-adipate) (PBSA), both biodegradable semicrystalline polyesters, were prepared with the ratio of PHBHHx/PBSA ranging from 80/20 to 20/80 by melt mixing method. Differential scanning calorimetry (DSC), thermogravimetry analysis (TGA), dynamic mechanical thermal analysis (DMA), polarizing optical microscopy (POM) and wide angle X-ray diffractometer (WAXD) were used to study the miscibility and crystallization behavior of PHBHHx/PBSA blends. Experimental results indicate that PHBHHx is immiscible with PBSA as shown by the almost unchanged glass transition temperature and the biphasic melt.

Combination of XianGui capsule and LCZ696 inhibits doxorubicin- induced heart failure in mice

Objective:We used doxorubicin(DOX)-induced heart failure mouse model to investigate the therapeutic effect and involved mechanism of XianGui capsule(XG)combined with Sacubitril Valsartan Sodium tablets(LCZ696)on heart failure.Methods:C57BL/6 mice were divided into control(Ctrl)group,DOX group,XG group,LCZ696 group and combination(XL)group.After the administration,mice heart functions,blood pressure,and serum cardiac injury markers were detected.Heart sections were conducted with HE,Sirius Red and immunohistochemical staining.The heart tissues were collected for the determination of protein or mRNA expression of anti oxidative,fibrosis,inflammation and apoptosis-related genes by Western Blot and qRT-PCR.Results:XG,LCZ696 or XG plus LCZ696 can significantly improve the heart functions of mice,reduce the expression of cardiac injury markers,and inhibit myocardial fibrosis.Mechanically,XG,LCZ696 or their co treatment antagonized myocardial apoptosis,increase forkhead box O3a,superoxide dismutase 2(SOD2)protein,SOD1,catalase mRNA expressions and inhibited the protein and mRNA levels of toll-like 4,nuclear factorkB,and inflammatory cytokines.Conclusion:XG,LCZ696 or XG plus LCZ696 decreases DOX-induced cardiomyocytes apoptosis by reducing inflammatory factors and enhancing expression of antioxidant enzymes,thereby alleviating the development of heart failure.

THE PREPARATION OF FRUCTOSE-MODIFIED CHITOSAN MICROCARRIERS AND CULTURE OF PRIMARY RAT HEPATOCYTES

The fructose modified chitosan microcarries (CMs) were prepared by the reaction of glutaraldehyde with fructose-modified chitosan. Various factors that influence the preparation were studied and the reaction conditions were optimized. Morphology of rat hepatocytes cultured on CMs was observed using phase contrast microscope and scanning electron microscope, and the metabolic activities were measured. Rat hepatocytes cultured on CMs retained the spherical shape as they have in vivo and had high metabolic activities. Fructose can enhance the metabolic activity of hepatocytes and the modified CMs are promising scaffold for hepatocytes attachment.

Metabolic Induction of Lactic Acid Bacteria for Urea Removal

Objective：This study aims to induce nonpathogenic bacteria for urea removal as a potential treatment in renal failure. Methods：Lactococus lactis MG1363 was induced by repeated exposure to urea-rich culture media, the ability to remove urea from the media was evaluated. The effect of gastroenteric environment, such as low pH, bile salt and antiagonistic properties were investigated. The antimicrobial activities on pathogenic E. coli and S. aureus in the intestinal tract and the antibiotic tolerance of the induced bacteria were also studied. Results ： Induced bacteria of 50 generations could decrease the urea level from 40.01 mg/dL to 32.99 mg/dL after 24 h. The bacteria could grow after treatment at pH3.0 for 2 h and in 0.1% bile salt for 6 h, and the urea removal activity was retained in such simulated gastroenteric environment. The removal of urea was significantly enhanced to 35.8% by addition of Ni^2＋ to the culture medium at neutral pH. It was also found that the induced bacteria could inhibit the growth of E. coli and S. aureus, and tolerate ampicillin, gentamicin, roxithromycin, tetracycline and cefradine. The safety tests were performed by feeding normal rats with either Lactococus lactis MG1363 or induced Laetococus lactis MG1363. The two materials did not cause any changes in blood cells, blood biochemical indexes and body weight. Conclusion： These results ＂suggest that the induced Laetoeocus lactis MG1363 has the potential as an oral therapy for the removal of urea in patients with renal failure.

Seamless and early gap healing of osteochondral defects by autologous mosaicplasty combined with bioactive supramolecular nanofiber-enabled gelatin methacryloyl(BSN-GelMA)hydrogel

Autologous mosaicplasty is a common approach used to treat osteochondral defects in clinical practice.Gap integration between host and transplanted plugs requires bone tissue reservation and hyaline cartilage regeneration without uneven surface,graft necrosis and sclerosis.However,poor gap integration is a serious concern,which eventually leads to deterioration of joint function.To deal with such complications,this study has developed a strategy to effectively enhance integration of the gap region following mosaicplasty by applying injectable bioactive supramolecular nanofiber-enabled gelatin methacryloyl(GelMA)hydrogel(BSN-GelMA).A rabbit osteochondral defect model demonstrated that BSN-GelMA achieved seamless osteochondral healing in the gap region between plugs of osteochondral defects following mosaicplasty,as early as six weeks.Moreover,the International Cartilage Repair Society score,histology score,glycosaminoglycan content,subchondral bone volume,and collagen II expression were observed to be the highest in the gap region of BSN-GelMA treated group.This improved outcome was due to bio-interactive materials,which acted as tissue fillers to bridge the gap,prevent cartilage degeneration,and promote graft survival and migration of bone marrow mesenchymal stem cells by releasing bioactive supramolecular nanofibers from the GelMA hydrogel.This study provides a powerful and applicable approach to improve gap integration after autologous mosaicplasty.It is also a promising off-the-shelf bioactive material for cell-free in situ tissue regeneration.

Supragel-mediated efficient generation of pancreatic progenitor clusters and functional glucose-responsive islet-like clusters

Although several synthetic hydrogels with defined stiffness have been developed to facilitate the proliferation and maintenance of human pluripotent stem cells(hPSCs),the influence of biochemical cues in lineage-specific differentiation and functional cluster formation has been rarely reported.Here,we present the application of Supragel,a supramolecular hydrogel formed by synthesized biotinylated peptides,for islet-like cluster differentiation.We observed that Supragel,with a peptide concentration of 5 mg/mL promoted spontaneous hPSCs formation into uniform clusters,which is mainly attributable to a supporting stiffness of∼1.5 kPa as provided by the Supragel matrix.Supragel was also found to interact with the hPSCs and facilitate endodermal and subsequent insulin-secreting cell differentiation,partially through its components:the sequences of RGD and YIGSR that interacts with cell membrane molecules of integrin receptor.Compared to Matrigel and suspension culturing conditions,more efficient differentiation of the hPSCs was also observed at the stages 3 and 4,as well as the final stage toward generation of insulin-secreting cells.This could be explained by 1)suitable average size of the hPSCs clusters cultured on Supragel;2)appropriate level of cell adhesive sites provided by Supragel during differentiation.It is worth noting that the Supragel culture system was more tolerance in terms of the initial seeding densities and less demanding,since a standard static cell culture condition was sufficient for the entire differentiation process.Our observations demonstrate a positive role of Supragel for hPSCs differentiation into islet-like cells,with additional potential in facilitating germ layer differentiation.

Mitochondrial sensitive probe with aggregation-induced emission characteristics for early brain diagnosis of Parkinson’s disease

The early diagnosis of Parkinson’s disease(PD)provides opportunities for early intervention to slow the progression of neurological degeneration in patients,particularly as the aging population increases in our society.Among a series of pathological features of PD,mitochondria abnormalities have been identified as central event that occurs at the early stage of PD.However,the method for detecting mitochondrial abnormalities-associated early PD has not been fully developed.We herein report a specifically mitochondrial targeting probe(named TPA-BT-SCP)that is able to characterize mitochondria abnormalities for early diagnosis of PD and monitor PD neurodegenerative progress.The probe is an aggregation-induced emission(AIE)probe with a strong positive charge,a 3D distorted molecular structure,and a separated HOMO-LUMO distribution,designed with unique molecular design guidelines.Our research demonstrated that TPA-BT-SCP could emit stable and strong fluorescence,and rapidly accumulate in mitochondria due to the negative charge.After intranasal administration of 1-methy-4-phenyl-1,2,3,6-tetrahydropyridine(MPTP)-induced PD mice,TPA-BT-SCP successfully bypassed the blood−brain barrier to light up the brain,allowing the grading of PD severity based on its high sensitivity.Taken together,this work develops a novel AIE probe that exhibits dramatically high sensitivity to mitochondrial changes and enables noninvasive diagnosis of early PD in the brain.

The deleterious effects and potential therapeutic strategy of fluorene-9-bisphenol on circadian activity and liver diseases in zebrafish and mice

Increasing evidence indicates that disturbance of the clock genes,which leads to systemic endocrine perturbation,plays a crucial role in the pathogenesis of metabolic and liver diseases.Fluorene-9-bisphenol(BHPF)is utilized in the manufacturing of plastic materials but its biological effects on liver homeostasis remain unknown.The impacts and involved mechanisms of BHPF on the liver diseases,metabolism,and circadian clock were comprehensively studied by zebrafish andmouse models.The therapeutic effect of melatonin(MT)was also verified.Zebrafish and mousemodels with either acute exposure(0.5 and 1μmol/L,1-4 days post-fertilization)or chronic oral exposure(0.5 and 50 mg/(kg·2 days),30 days)were established with various BHPF concentrations.Herein,we identified a crucial role for estrogenic regulation in liver development and circadian locomotor rhythms damaged by BHPF in a zebrafish model.BHPF mice showed chaos in circadian activity through the imbalance of circadian clock component Brain and Muscle Aryl hydrocarbon receptor nuclear translocator-like 1 in the liver and brain.The liver sexual dimorphic alteration alongwith reduced growth hormone and estrogens played a critical role in damaged glucose metabolism,hepatic inflammation,and fibrosis induced by BHPF.Besides,sleep improvement by exogenous MT alleviated BHPF-related glucose metabolism and liver injury in mice.We proposed the pathogenesis of metabolic and liver disease resulting from BHPF and promising targeted therapy for livermetabolism disorders associated with endocrine perturbation chemicals.These results might play a warning role in the administration of endocrine-disrupting chemicals in everyday life and various industry applications.