Meta-analysis identifying gut microbial biomarkers of Qinghai-Tibet Plateau populations and the functionality of microbiota-derived butyrate in high-altitude adaptation.

The extreme environmental conditions of a plateau seriously threaten human health. The relationship between gut microbiota and human health at high altitudes has been extensively investigated. However, no universal gut microbiota biomarkers have been identified in the plateau population, limiting research into gut microbiota and high-altitude adaptation. 668 16s rRNA samples were analyzed using meta-analysis to reduce batch effects and uncover microbiota biomarkers in the plateau population. Furthermore, the robustness of these biomarkers was validated. Mendelian randomization (MR) results indicated that Tibetan gut microbiota may mediate a reduced erythropoietic response. Functional analysis and qPCR revealed that butyrate may be a functional metabolite in high-altitude adaptation. A high-altitude rat model showed that butyrate reduced intestinal damage caused by high altitudes. According to cell experiments, butyrate may downregulate hypoxia-inducible factor-1α (HIF-1α) expression and blunt cellular responses to hypoxic stress. Our research found universally applicable biomarkers and investigated their potential roles in promoting human health at high altitudes.

3D Printing Silk Fibroin/Polyacrylamide Triple-Network Composite Hydrogels with Stretchability, Conductivity, and Strain-Sensing Ability as Bionic Electronic Skins.

Electronic skins have received increasing attention due to their great application potential in wearable electronics. Meanwhile, tremendous efforts are still needed for the fabrication of multifunctional composite hydrogels with complex structures for electronic skins via simple methods. In this work, a novel three-dimensional (3D) printing composite hydrogel with stretchability, conductivity, and strain-sensing ability is produced using a one-step photocuring method to achieve a dual-signal response of the electronic skin. The composite hydrogel exhibits a triple-network structure composed of silk microfibers (SMF), regenerated silk fibroin (RSF), and polyacrylamide (PAM). The establishment of triple networks is based on the electrostatic interaction between SMF and RSF, as well as the chemically cross-linked RSF and PAM. Thanks to its specific structure and components, the composite hydrogel possesses enhanced mechanical properties (elastic modulus of 140 kPa, compressive stress of 21 MPa, and compression modulus of 600 kPa) and 3D printability while retaining stretchability and flexibility. The interaction between negatively charged SMF and cations in phosphate-buffered saline endows the composite hydrogel with good conductivity and strain-sensing ability after immersion in a low-concentration (10 mM) salt solution. Moreover, the 3D printing composite hydrogel scaffold successfully realizes real-time monitoring. Therefore, the proposed hydrogel-based ionic sensor is promising for skin tissue engineering, real-time monitoring, soft robotics, and human-machine interfaces.

Accuracy of digital implant impressions using a novel structured light scanning system assisted by a planar mirror in the edentulous maxilla: An in vitro study.

OBJECTIVES: This study aimed to develop a structured light scanning system with a planar mirror to enhance the digital full-arch implant impression accuracy and to compare it with photogrammetry and intraoral scanner methods. MATERIALS AND METHODS: An edentulous maxillary stone cast with six scan bodies was scanned as the reference model using a laboratory scanner. Three scanning modalities were compared (n = 10): (1) self-developed structured light scanning with a mirror (SSLS); (2) intraoral scanner (IOS); and (3) photogrammetry system (PG). The scanners were stopped for 1 min after each scan. Six scan bodies were analysed within each scan model. Linear deviations between the scan bodies (1-2, 1-3, 1-4, 1-5, and 1-6) and 3D mucosal deviations were established. The overall deviation was calculated as the mean of all linear deviations. "Trueness" represented the discrepancy between the test and reference files, while "precision" denoted the consistency among the test files. Kruskal-Wallis and Mann-Whitney U tests were used for statistical analyses. RESULTS: Significant overall linear discrepancies were noted among the SSLS, PG, and IOS groups (p < .001). SSLS showed the best overall trueness and precision (6.6, 5.7 µm), followed by PG (58.4, 6.8 µm) and IOS (214.6, 329.1 µm). For the 3D mucosal deviation, the trueness (p < .001) and precision (p < .001) of the SSLS group were significantly better than those of the IOS group. CONCLUSIONS: The SSLS exhibited higher accuracy in determining the implant positions than the PG and IOS. Additionally, it demonstrated better accuracy in capturing the mucosa than IOS.

Endoclip papillaplasty (ECPP) versus limited EST plus EPLBD for a decrease in recurrent choledocholithiasis: a prospective cohort study.

BACKGROUND AND AIMS: Limited EST plus EPLBD has been widely used for the therapy of large CBDS; however, long-term complication-relevant studies suggested that it damaged the function of the sphincter of Oddi (SO) and resulted in recurrent choledocholithiasis. Thus, we designed Endoclip papillaplasty (ECPP) and previous studies have shown that it successfully restored the function of SO. In this study, we designed a prospective cohort and aimed to verify the safety and effectiveness of ECPP. METHODS: Eligible patients were divided into the ECPP group and the limited EST plus EPLBD group based on papillary morphology and the ratio of maximum size of stones to length of intramural segments of CBD. All participants in the ECPP group received endoscopy at 3 weeks to retrieve the biliary stent, perform SOM, and were divided into grade A and grade B based on the healing grade of SO. All patients were followed up every 6 months until recurrent choledocholithiasis, patient death, or at the 36-month follow-up end. The primary outcome was the incidence of recurrent choledocholithiasis. The secondary outcomes included mechanical lithotrip usage and adverse events. RESULTS: The incidences of recurrent choledocholithiasis in the ECPP group and limited EST plus EPLBD group were 13.6 and 22.1%, respectively (P = 0.204). The ECPP-A group had a lower incidence of recurrent choledocholithiasis than the limited EST plus EPLBD groups (5.1 vs. 22.1%, P = 0.020*), and certified the function of SO successfully restored in the ECPP-A group. CONCLUSION: The ECPP-A group had a decrease in recurrent choledocholithiasis, and ECPP was safe and effective for CBDS.

Genetic diversity, plant growth promotion potential, and antimicrobial activity of culturable endophytic actinobacteria isolated from Aconitum carmichaelii Debeaux.

AIM: This study evaluated the phylogenetic diversity, plant growth promotion capacity, antifungal activity, and biocontrol potential of culturable actinobacterial endophytes isolated from the medicinal plant Aconitum carmichaelii Debeaux. METHODS AND RESULTS: Isolation of actinobacteria from healthy A. carmichaelii plants was carried out on six different media. Full-length 16S rRNA gene was amplified by PCR from the genomic DNA of each strain. Indole-3-acetic acid and siderophore production were quantitatively assessed by the Salkowski and Chrome Azurol S methods, respectively. Rice seeds germination and seedling growth were employed to evaluate plant growth promotion capacities of candidate strains. Dual-culture assay and pot experiments were performed to investigate the antifungal and biocontrol potential of isolates. We obtained 129 actinobacterial isolates from A. carmichaelii, and they belonged to 49 species in 7 genera. These strains exhibited diverse plant growth promotion ability, among which one strain significantly enhanced rice seeds germination, while 31 strains significantly facilitated rice seedling growth. SWUST-123 showed strong antifungal activity against four pathogens in vitro and was most compatible with Qingchuan cultivar. SWUST-123 reduced around 40% of southern blight disease occurrence compared to blank control treatment. . CONCLUSION: Aconitum carmichaelii harbored genetically diverse actinobacterial endophytes exhibiting diverse plant growth promotion and antifungal potential, some of which can be served as good candidates for biofertilizers and biocontrol agents.

Comparing the accuracy of full-arch implant impressions using the conventional technique and digital scans with and without prefabricated landmarks in the mandible: An in vitro study.

OBJECTIVES: This study evaluated the accuracy of digital implant impressions with or without prefabricated landmarks compared with the conventional method in the edentulous mandible. METHODS: An edentulous mandibular stone cast with implant abutment analogs and scan bodies in FDI #46, #43, #33, and #36 served as the master model. The scans captured with intraoral scanners (IOS) were divided into four groups: IOS-NT (no landmarks + Trios 4 scanner), IOS-NA (no landmarks + Aoralscan 3 scanner), IOS-YT (landmarks + Trios 4 scanner), and IOS-YA (landmarks + Aoralscan 3 scanner) (n=10). Landmarks were attached to the scan bodies with resin to improve scanning fluency. Conventional open-trayed technique (CNV) was performed with the 3D-printed splinting frameworks (n=10). The master model and conventional castings were scanned using a laboratory scanner, and the former served as the reference model. Overall distance and angle deviations between scan bodies were measured to determine trueness and precision. The ANOVA or Kruskal-Wallis test compared CNV group to scans without landmarks, while a generalized linear model analyzed scan groups with and without landmarks. RESULTS: Compared to the CNV group, the IOS-NA and IOS-NT groups showed higher overall distance trueness (p=0.009), and precision (distance, p<0.001 and angular, p<0.001). With landmarks, the IOS-YA group had higher overall trueness (distance, p<0.001 and angular, p<0.001) than the IOS-NA group, and the IOS-YT group has higher distance trueness (p=0.041) than the IOS-NT group. Moreover, the precision in distance and angle was significantly improved for IOS-YA and IOS-YT groups, compared with the IOS-NA (p<0.001) and IOS-NT (p<0.001) groups separately. CONCLUSIONS: Digital scans were more accurate than conventional splinting open-trayed impressions. Prefabricated landmarks significantly improved the accuracy of full-arch implant digital scans, regardless of the scanner used. CLINICAL SIGNIFICANCE: Prefabricated landmarks can enhance the accuracy of intraoral scanners for full-arch implant rehabilitation, improving scanning efficiency and clinical outcomes.

Establishment and evaluation of a three-dimensional quantitative analysis method of dental plaque based on intraoral scanner technique.

AIM: Quantitative dental plaque evaluation is necessary for clinical and scientific work. This study aimed to examine the reliability of this 3D image analysis method by digitally analysing the colour 3D images obtained from an intraoral scanner, and then detecting and quantifying the plaque information and comparing it with the clinical examination results. MATERIALS AND METHODS: A total of 140 teeth from 5 subjects with a standard dentition were enrolled in this study, and plaque examination was performed at two different stages: after 24 hours without oral hygiene (T1) and after habitual brushing (T2). At each time point, the Quigley-Hein plaque index of each tooth surface was recorded separately, followed by colour 3D images obtained using an intraoral scanner, and image analysis and calculation using Geomagic Wrap 2021. RESULTS: It was found that the percentage of plaque staining area calculated from the 3D image analysis correlated well with the plaque index recorded during the clinical examination: the Spearman correlation coefficients were 0.9136 and 0.9061 (p<0.001) for all tooth surfaces at T1 and T2, respectively. The measurements of the three investigators were in good agreement, with intraclass correlation coefficients of 0.989 and 0.992 (P<0.001) for the vestibular and lingual surfaces at T1, and 0.964 and 0.983 (P<0.001) for the vestibular and lingual surfaces at T2. CONCLUSION: In this study, we initially developed a digital 3D evaluation system of dental plaque suitable for research and clinical practice and demonstrated its reliability.

Fiber diameters and parallel patterns: proliferation and osteogenesis of stem cells.

Due to the innate extracellular matrix mimicking features, fibrous materials exhibited great application potential in biomedicine. In developing excellent fibrous biomaterial, it is essential to reveal the corresponding inherent fiber features' effects on cell behaviors. Due to the inevitable 'interference' cell adhesions to the background or between adjacent fibers, it is difficult to precisely reveal the inherent fiber diameter effect on cell behaviors by using a traditional fiber mat. A single-layer and parallel-arranged polycaprolactone fiber pattern platform with an excellent non-fouling background is designed and constructed herein. In this unique material platform, the 'interference' cell adhesions through interspace between fibers to the environment could be effectively ruled out by the non-fouling background. The 'interference' cell adhesions between adjacent fibers could also be excluded from the sparsely arranged (SA) fiber patterns. The influence of fiber diameter on stem cell behaviors is precisely and comprehensively investigated based on eliminating the undesired 'interference' cell adhesions in a controllable way. On the SA fiber patterns, small diameter fiber (SA-D1, D1 means 1 µm in diameter) may seriously restrict cell proliferation and osteogenesis when compared to the middle (SA-D8) and large (SA-D56) ones and SA-D8 shows the optimal osteogenesis enhancement effect. At the same time, the cells present similar proliferation ability and even the highest osteogenic ability on the densely arranged (DA) fiber patterns with small diameter fiber (DA-D1) when compared to the middle (DA-D8) and large (DA-D56) ones. The 'interference' cell adhesion between adjacent fibers under dense fiber arrangement may be the main reason for inducing these different cell behavior trends along with fiber diameters. Related results and comparisons have illustrated the effects of fiber diameter on stem cell behaviors more precisely and objectively, thus providing valuable reference and guidance for developing effective fibrous biomaterials.

Bioactive polymer-enabled conformal neural interface and its application strategies.

Neural interface is a powerful tool to control the varying neuron activities in the brain, where the performance can directly affect the quality of recording neural signals and the reliability of in vivo connection between the brain and external equipment. Recent advances in bioelectronic innovation have provided promising pathways to fabricate flexible electrodes by integrating electrodes on bioactive polymer substrates. These bioactive polymer-based electrodes can enable the conformal contact with irregular tissue and result in low inflammation when compared to conventional rigid inorganic electrodes. In this review, we focus on the use of silk fibroin and cellulose biopolymers as well as certain synthetic polymers to offer the desired flexibility for constructing electrode substrates for a conformal neural interface. First, the development of a neural interface is reviewed, and the signal recording methods and tissue response features of the implanted electrodes are discussed in terms of biocompatibility and flexibility of corresponding neural interfaces. Following this, the material selection, structure design and integration of conformal neural interfaces accompanied by their effective applications are described. Finally, we offer our perspectives on the evolution of desired bioactive polymer-enabled neural interfaces, regarding the biocompatibility, electrical properties and mechanical softness.

Root endophytic bacterial community composition of Aconitum carmichaelii debx. from three main producing areas in China.

Aconitum carmichaelii Debx. is famous for the bioactive aconitum alkaloids as traditional Chinese medicine. Endophytic bacteria play vital roles in plant growth, health, and the production of secondary metabolites such as alkaloids. In this study, we employed 16 S rRNA amplicon high-throughput sequencing to determine the root endophytic bacterial community of A. carmichaelii Debx. collected from three main producing areas including the geo-authentic area in China, high performance liquid chromatography to measure the contents of six bioactive alkaloids and correlation analysis to explore the relationship among environmental factors, alkaloids contents, and endophytic bacterial community. The results indicated that the root core microbiota of A. carmichaelii Debx. was dominated by Proteobacteria, Bacteroidetes, Firmicutes, and Actinobacteria. Root endophytic bacterial community in the geo-authentic area was distinct from the other two regions. Soil nitrogen contents, organic matter, and temperature were the main factors contributing to the endophytic bacterial community structure. Significant correlation was found between alkaloids contents and some bacterial genera. Particularly, the abundance of Lactobacillus was positively correlated with the contents of benzoyl-mesaconitine and benzoyl-aconine. This study provided the first insight into the root endophytic bacterial community composition of A. carmichaelii Debx., and can direct further isolation of functional bacterial strains.

Nonmulberry silk fibroin-based biomaterials: Impact on cell behavior regulation and tissue regeneration.

Silk fibroin (SF) is a promising biomaterial due to its good biocompatibility, easy availability, and high mechanical properties. Compared with mulberry silk fibroin (MSF), nonmulberry silk fibroin (NSF) isolated from typical nonmulberry silkworm silk exhibits unique arginine-glycine-aspartic acid (RGD) sequences with favorable cell adhesion enhancing effect. This inherent property probably makes the NSF more suitable for cell culture and tissue regeneration-related applications. Accordingly, various types of NSF-based biomaterials, such as particles, films, fiber mats, and 3D scaffolds, are constructed and their application potential in different biomedical fields is extensively investigated. Based on these promising NSF biomaterials, this review firstly makes a systematical comparison between the molecular structure and properties of MSF and typical NSF and highlights the unique properties of NSF. In addition, we summarize the effective fabrication strategies from degummed nonmulberry silk fibers to regenerated NSF-based biomaterials with controllable formats and their recent application progresses in cell behavior regulation and tissue regeneration. Finally, current challenges and future perspectives for the fabrication and application of NSF-based biomaterials are discussed. Related research and perspectives may provide valuable references for designing and modifying effective NSF-based and other natural biomaterials. STATEMENT OF SIGNIFICANCE: There exist many reviews about mulberry silk fibroin (MSF) biomaterials and their biomedical applications, while that about nonmulberry silk fibroin (NSF) biomaterials is scarce. Compared with MSF, NSF exhibits unique arginine-glycine-aspartic acid sequences with promising cell adhesion enhancing effect, which makes NSF more suitable for cell culture and tissue regeneration related applications. Focusing on these advanced NSF biomaterials, this review has systematically compared the structure and properties of MSF and NSF, and emphasized the unique properties of NSF. Following that, the effective construction strategies for NSF-based biomaterials are summarized, and their recent applications in cell behavior regulations and tissue regenerations are highlighted. Furthermore, current challenges and future perspectives for the fabrication and application of NSF-based biomaterials were discussed.

Bioinspired silk fibroin materials: From silk building blocks extraction and reconstruction to advanced biomedical applications.

Silk fibroin has become a promising biomaterial owing to its remarkable mechanical property, biocompatibility, biodegradability, and sufficient supply. However, it is difficult to directly construct materials with other formats except for yarn, fabric and nonwoven based on natural silk. A promising bioinspired strategy is firstly extracting desired building blocks of silk, then reconstructing them into functional regenerated silk fibroin (RSF) materials with controllable formats and structures. This strategy could give it excellent processability and modifiability, thus well meet the diversified needs in biomedical applications. Recently, to engineer RSF materials with properties similar to or beyond the hierarchical structured natural silk, novel extraction and reconstruction strategies have been developed. In this review, we seek to describe varied building blocks of silk at different levels used in biomedical field and their effective extraction and reconstruction strategies. This review also present recent discoveries and research progresses on how these functional RSF biomaterials used in advanced biomedical applications, especially in the fields of cell-material interactions, soft tissue regeneration, and flexible bioelectronic devices. Finally, potential study and application for future opportunities, and current challenges for these bioinspired strategies and corresponding usage were also comprehensively discussed. In this way, it aims to provide valuable references for the design and modification of novel silk biomaterials, and further promote the high-quality-utilization of silk or other biopolymers.

Benzoic Acid Metabolism and Lipopolysaccharide Synthesis of Intestinal Microbiome Affects the Health of Ruminants under Free-Range and Captive Mode.

It is urgent to explore new ways to protect endangered wild animals and develop sustainable animal husbandry on the Qinghai-Tibet Plateau due to its fragile ecological environment. Ruminants, raised in captivity and free-range, have important niches in the Plateau and are the best models to analyze the effects of different feeding modes on their health. In this study, two ruminants, yaks and goats in free-range and captive modes, respectively, were selected to study the relationship between gut microbes and ruminant health. The results showed that the gut microbial diversity of free-range ruminants was higher than those of captive ruminants. Principal co-ordinates analysis (PCoA) showed that there were significant differences in the gut microbial communities in different breeding modes. Both the captive ruminants enriched the Succinivibrionaceae family, which had a strong potential to synthesize lipopolysaccharide, and the low exercise amount of the captive animals was significantly related to this function. Meanwhile, free-range ruminants enriched Oscillospiraceae, which had the potential to degrade benzoic acid, and this potential had a significant positive correlation with resistance to parasitic infections. We offer other possibilities, such as adding benzoic acid to feed or increasing the exercise time of captive ruminants to make them healthier.

Enteral extended biliary stents versus conventional plastic biliary stents for the treatment of extrahepatic malignant biliary obstruction: a single-center prospective randomized controlled study.

BACKGROUND AND AIMS: The main limitation of plastic stents is the relatively short stent patency due to occlusion. We designed enteral extended biliary stents with lengths of 26 cm (EEBS-26 cm) and 30 cm (EEBS-30 cm) to prolong stent patency. This study aimed to compare patency among EEBS-26 cm, EEBS-30 cm, and conventional plastic biliary stent (CPBS). METHODS: A single-center prospective randomized controlled study was conducted. Eligible patients were randomized into the EEBS-26 cm, EEBS-30 cm, and CPBS groups, respectively. All patients were followed up every 3 months until stent occlusion, patient death, or at 12-month follow-up. The primary outcome was stent patency. The secondary outcomes included stent occlusion rate, patient survival, mortality, the rate of technical success, and adverse events. RESULTS: Totally 117 patients were randomized into the three groups. There were no significant differences among the three groups in technical success rate, hospital stay, mortality, patient survival, and adverse events (P = 1.000, 0.553, 0.965, 0.302, and 0.427, respectively). Median stent patency durations in the EEBS-26 cm, EEBS-30 cm, and CPBS groups were 156.0 (95% CI 81.6-230.4) days, 81.0 (95% CI 67.9-94.1) days, and 68.0 (95% CI 20.0-116.0) days, respectively (P = 0.002). The EEBS-26 cm group had longer stent patency compared with the CPBS (P = 0.007) and EEBS-30 cm (P < 0.001) groups. The EEBS-26 cm group had lower stent occlusion rates compared with the other groups at 6 months (48.1% vs. 90.5% vs. 82.8%, P = 0.001) and 9 months (75.0% vs. 100.0% vs. 92.9%, P = 0.022). CONCLUSION: EEBS-26 cm has prolonged stent patency and is safe and effective for the alleviation of unresectable extrahepatic malignant biliary obstruction.

Efficacy of oral steroid gel in preventing esophageal stricture after extensive endoscopic submucosal dissection: a randomized controlled trial.

BACKGROUND AND AIMS: Esophageal stricture is a distressing issue for patients with early esophageal cancer following extensive endoscopic submucosal dissection (ESD), and the current steroid-based approaches are unsatisfactory for stricture prophylaxis. We evaluated the efficacy of oral hydrocortisone sodium succinate and aluminum phosphate gel (OHA) for stricture prophylaxis after extensive ESD. METHODS: Patients undergoing > 3/4 circumferential ESD were randomized to either the endoscopic loco-regional triamcinolone acetonide injection (ETI) plus oral prednisone group or the OHA group. The primary endpoint was incidence of esophageal stricture, and the secondary endpoints included adverse events (AEs) and endoscopic balloon dilations (EBDs). RESULTS: The incidence of esophageal stricture in OHA group (per-protocol analysis, 9.4%, 3/32; intention-to-treat analysis, 12.1%, 4/33) was significantly less than that of control group (per-protocol analysis, 35.5%, 11/31, P = 0.013; intention-to-treat analysis, 39.4%, 13/33, P = 0.011). Two sessions of EBD were necessary to release all strictures in the OHA group, while the similar EBDs (median 2, range 1-4) for 11 of the control. Operation-related AEs included infection (control vs. OHA group = 9.7% vs. 31.3%, P = 0.034), operation-related hypokalemia (19.4% vs. 31.3%, P = 0.278), perforation (3.2% vs. 3.1%), post-ESD hemorrhage (6.5% vs. 0%), and cardiac arrhythmia (0% vs. 6.3%). Steroid-related AEs included steroid-related hypokalemia (16.1% vs. 25%) and bone fracture (3.2% vs. 0%). Multivariate logistic regression analysis demonstrated that OHA was an independent protective factor for stricture (OR 0.079; 95%CI 0.011, 0.544; P = 0.01) and mucosal defect > 11/12 circumference was an independent risk factor (OR 49.91; 95%CI 6.7, 371.83; P < 0.001). CONCLUSIONS: OHA showed significantly better efficacy in preventing esophageal stricture after > 3/4 circumferential ESD compared to ETI plus oral prednisone.

3D-Printed Strong Dental Crown with Multi-Scale Ordered Architecture, High-Precision, and Bioactivity.

Mimicking the multi-scale highly ordered hydroxyapatite (HAp) nanocrystal structure of the natural tooth enamel remains a great challenge. Herein, a bottom-up step-by-step strategy is developed using extrusion-based 3D printing technology to achieve a high-precision dental crown with multi-scale highly ordered HAp structure. In this study, hybrid resin-based composites (RBCs) with "supergravity +" HAp nanorods can be printed smoothly via direct ink writing (DIW) 3D printing, induced by shear force through a custom-built nozzle with a gradually shrinking channel. The theoretical simulation results of finite element method are consistent with the experimental results. The HAp nanorods are first highly oriented along a programmable printing direction in a single printed fiber, then arranged in a layer by adjusting the printing path, and finally 3D printed into a highly ordered and complex crown structure. The printed samples with criss-crossed layers by interrupting crack propagation exhibit a flexural strength of 134.1 ± 3.9 MPa and a compressive strength of 361.6 ± 8.9 MPa, which are superior to the corresponding values of traditional molding counterparts. The HAp-monodispersed RBCs are successfully used to print strong and bioactive dental crowns with a printing accuracy of 95%. This new approach can help provide customized components for the clinical restoration of teeth.

One-Step Approach to Prepare Transparent Conductive Regenerated Silk Fibroin/PEDOT:PSS Films for Electroactive Cell Culture.

Silk fibroin (SF)-based electroactive biomaterials with favorable electroconductive property and transparency have great potential applications for cell culture and tissue engineering. Poly(3,4-ethylenedioxythiophene)-poly(styrenesulfonate) (PEDOT:PSS) is an excellent candidate as a conductive component, which has been widely used in the field of bioelectronics; however, it is hard to be directly coated onto the surface of regenerated SF (RSF) materials with good stability under a cell culture environment. In this study, a one-step facile PEDOT:PSS modification approach for RSF films based on a suitable post-treatment process of RSF was developed. PEDOT:PSS was successfully embedded and fixed into the shallow surface of an RSF film, forming a tightly conjunct conductive layer on the film surface based on the conformation transition of RSF during the post-treatment process. The conductive layer demonstrated a PSS-rich surface and a PEDOT-rich bulk structure and showed excellent stability under a cell culture environment. More specifically, the robust RSF/PEDOT:PSS film achieved in the post-treatment formula with 70% ethanol proportion possessed best comprehensive properties such as a sheet resistance of 3.833 × 103 Ω/square, a conductivity of 1.003 S/cm, and transmittance over 80% at maximum in the visible range. This kind of electroactive biomaterial also showed good electrochemical stability and degradable properties. Moreover, pheochromocytoma-derived cell line (PC12) cells were cultured on the RSF/PEDOT:PSS film, and an effective electrical stimulation cell response was demonstrated. The facile preparation strategy and the good electroconductive property and transparency make this RSF/PEDOT:PSS film an ideal candidate for neuronal tissue engineering and further for biomedical applications.

Electrospun regenerated silk fibroin is a promising biomaterial for the maintenance of inner ear progenitors in vitro.

OBJECTIVE: We sought to determine the biocompatibility of electrospun regenerated silk fibroin (RSF) mats with inner ear progenitors, especially their effect on the differentiation of inner ear progenitors into hair cells. METHODS: Neonatal mouse cochleae (n = 20) were collected and digested and allowed to form spheres over several days. Cells digested from the spheres were then seeded onto aligned or random RSF mats, with laminin-coated coverslips serving as controls. The inner ear progenitor cell mortality was examined by TUNEL labeling, and the adhesion of cells to the RSF mats or coverslip was determined by scanning electron microscopy. Finally, the number of hair cells that differentiated from inner ear progenitors was determined by Myosin7a expression. Unpaired Student's t-tests and one-way ANOVA followed by a Dunnett's multiple comparisons test were used in this study (p < 0.05). RESULTS: After 5 days of culture, the inner ear progenitors had good adhesion to both the aligned and random RSF mats and there was no significant difference in TUNEL+ cells between the mats compared to the coverslip (p > 0.05). After 7 days of in vitro differentiation culture, the percentage of differentiated hair cells on the control, aligned, and random RSF mats was 2.5 ± 0.5%, 2.7 ± 0.4%, and 2.4 ± 0.2%, respectively, and there was no significant difference between Myosin7a+ cells on either RSF mat compared to controls (p > 0.05). CONCLUSION: The aligned and random RSF mats had excellent biocompatibility with inner ear progenitors and helped the inner ear progenitors maintain their stemness. Our results thus indicate that RSF mats represent a useful scaffold for the development of new strategies for inner ear tissue engineering research.

Biocontrol and plant growth promotion potential of endophytic Bacillus subtilis JY-7-2L on Aconitum carmichaelii Debx.

Aconitum carmichaelii Debx. is a famous medicinal plant rich in alkaloids and widely used to treat various human diseases in Asian countries. However, southern blight caused by Sclerotium rolfsii severely hampered the yield of A. carmichaelii. Beneficial microbe-based biological control is becoming a promising alternative and an environmentally friendly approach for the management of plant diseases. In this study, we evaluated the biocontrol potential of an endophytic bacterial strain JY-7-2L, which was isolated from the leaves of A. carmichaelii, against southern blight in vitro and by a series of field experiments. JY-7-2L was identified as Bacillus subtilis based on multi-locus sequence analysis. JY-7-2L showed strong antagonistic activity against S. rolfsii in vitro and on A. carmichaelii root slices by dual-culture assay. Cell-free culture filtrate of JY-7-2L significantly inhibited the hyphal growth, sclerotia formation, and germination of S. rolfsii. In addition, volatile compounds produced by JY-7-2L completely and directly inhibited the growth of S. rolfsii. Furthermore, JY-7-2L was proved to produce hydrolytic enzymes including glucanase, cellulase, protease, indole acetic acid, and siderophore. The presence of bacA, fenA, fenB, fenD, srfAA, and baeA genes by PCR amplification indicated that JY-7-2L was able to produce antifungal lipopeptides and polyketides. Field trials indicated that application of the JY-7-2L fermentation culture significantly reduced southern blight disease severity by up to 30% with a long-acting duration of up to 62 days. Meanwhile, JY-7-2L significantly promoted the fresh and dry weights of the stem, main root, and lateral roots of A. carmichaelii compared to non-inoculation and/or commercial B. subtilis product treatments. Taken together, JY-7-2L can be used as a promising biocontrol agent for the control of southern blight in A. carmichaelii.

Effects of compound stimulation of fluid shear stress plus ultrasound on stem cell proliferation and osteogenesis.

Bone tissue with strong adaptability is often in a complex dynamical microenvironment in vivo, which is associated with the pathogenesis and treatment of orthopedic diseases. Therefore, it is of great significance to investigate the effects of corresponding compound stimulation on cell behaviors. Herein, a fluid shear stress (FSS) plus ultrasound stimulation platform suitable for cell studies based on a microfluidic chip was constructed and bone marrow mesenchymal stem cell (BMSC) was chosen as a model cell. The proliferation and osteogenesis of BMSCs under the compound stimulation of FSS plus ultrasound in growth medium without any soluble induction factors were firstly investigated. Single FSS stimulation and static culture conditions were also examined. Results illustrated that suitable single FSS stimulation (about 0.06 dyn/cm2) could significantly enhance cell proliferation and osteogenesis simultaneously when compared to the static control, while greater FSS mitigated or even restricted these enhancing effects. Interestingly, ultrasound stimulation combined with this suitable FSS stimulation further accelerated cell proliferation as the intensity of ultrasound increasing. As for the osteogenesis under compound stimulation, it was relatively restricted under lower ultrasound intensity (about 0.075 W/cm2), while promoted when the intensity became higher (about 1.75 W/cm2). This study suggests that both the cell proliferation and osteogenesis are very responsive to the magnitudes of FSS and ultrasound stimulations and can be both significantly enhanced by proper combination strategies. Moreover, these findings will provide valuable references for the construction of effective cell bioreactors and also the treatment of orthopedic diseases.