A nature-inspired multifunctional adhesive for cartilage tissue-biomaterial integration.

Surgical adhesives play a crucial role in tissue integration and repair, yet their application in wet conditions has been severely limited by inadequate adhesive strength and subpar biocompatibility. Furthermore, tissue adhesives have rarely been reported in cartilage tissue repair. In this study, a three-armed dopamine-modified hyaluronic acid derivative adhesive was prepared to function as a bio-inspired adhesive in moist environments. To meet the clinical requirements for cartilage tissue adhesion, we studied its chemical structure, including microscopic morphology, adhesion properties with materials and tissues, in vivo degradation rules, and biological evaluation. The OGMHA8-DOPA adhesive with the optimal aldehyde substitution degree and dopamine-grafting rate was determined by analyzing the experimental conditions. SEM results revealed that the cartilage tissue adhered to a porous interconnected structure. The excellent biocompatibility of the material not only facilitated chondrocyte adhesion but also supported their proliferation on its surface. Animal experiments have demonstrated that this material has no observable inflammatory response or incidence of fibrous capsule formation. The degradation timeline of the material extends beyond the duration of two weeks. The dopamine-modified adhesive exhibited a tight interfacial binding force between the biomaterial and cartilage tissue and excellent biocompatibility in watery tissue, revealing its potential for application in cartilage tissue repair and minimally invasive surgery.

Silk fibroin/chitosan/TGF-ß1-loaded microsphere scaffolds for cartilage reparation.

BACKGROUND: Transforming growth factor-ß1 (TGF-ß1) plays an important role in chondrocyte growth and the synthesis of extracellular matrix (ECM). Due to the rapid metabolism, controlled release systems for TGF-ß1 have attracted increasing interest recently. OBJECTIVE: In this study, a silk fibroin (SF)/chitosan (CS) scaffold incorporated with TGF-ß1-loaded microspheres (MSs) was created for cartilage reparation. METHOD: The optimal proportion of the SF/CS composite scaffold was determined by evaluating their micromorphology and the proliferation rate of fibroblasts on the surface. Then, SF/CS/TGF-ß1-loaded MS scaffolds were prepared by the adsorption method. TGF-ß1 release capacity, degradation patterns, cytocompatibility and in vivo implantation were evaluted. RESULTS: The SF/CS/TGF-ß1-loaded MS scaffold showed good TGF-ß1 release over more than 16 days, which could sequentially stimulate chondrocyte synthetic activity. In vitro cell proliferation experiments showed the SF/CS/TGF-ß1-loaded MS scaffold could promote chondrocytes adhesion, growth, proliferation and maintained the cellular morphology. An in vivo study demonstrated that a low inflammatory response was observed in rats and that the materials exhibited good biocompatibility. CONCLUSION: the results indicated that our SF/CS/TGF-ß1-loaded MS scaffold constitute a promising therapeutic option for cartilage reparation.

Proangiogenic Peptide Nanofiber Hydrogels for Wound Healing.

Rapid vascularization is vital for dermal regeneration, nutrient and nutrition transfer, metabolic waste removal, and prevention of infection. This study reports on a series of proangiogenic peptides designed to undergo self-assembly and promote angiogenesis and hence skin regeneration. The proangiogenic peptides comprised an angiogenic peptide segment, GEETEVTVEGLEPG, and a ß-sheet structural peptide sequence. These peptides dissolved easily in ultrapure water and rapidly self-assembled into hydrogels in a pH-dependent manner, creating three-dimensional fibril network structures and nanofibers as revealed by a scanning microscope and a transmission electron microscope. In vitro experiments showed that the peptide hydrogels favored adhesion and proliferation of mouse fibroblasts (L929) and human umbilical vein endothelial cells (HUVECs). In particular, many connected tubes were formed in the HUVECs after 8 h of culture on the peptide hydrogels. In vivo experiments demonstrated that new blood vessels grew into the proangiogenic peptide hydrogels within 2 weeks after subcutaneous implantation in mice. Moreover, the proangiogenic-combined hydrogels exhibited faster repair cycles and better healing of skin defects. Collectively, the results indicate that the proangiogenic peptide hydrogels are a promising therapeutic option for skin regeneration.

Hemostatic Effect of Aminated Multiwalled Carbon Nanotubes/Oxidized Regenerated Cellulose Nanocomposites.

We have investigated the covalent conjugation of aminated multiwalled carbon nanotubes (MWCNTNH2)s with Oxidized Regenerated Cellulose (ORC) in order to enhance the hemostatic effect. The MWCNT-NH2s were prepared by functionalization of pristine MWCNTs (pMWCNTs) using amine groups. Neat ORC gauze and MWCNT-NH2s were reacted using glutamic acid as cross linking bridge. We investigated an amination of pMWCNTs as well as the dispersion of MWCNT-NH2s in the ORC gauze as matrix and their interfacial interactions by SEM and FT-IR. The results revealed that relatively strong interaction exists between aminated MWCNTs and the ORC macromolecules. The hydrophilicity test results in the significant increment of water uptake of MWCNT-NH2s/ORC composites with increasing the concentration of MWCNT-NH2s in composite. The in-vitro procoagulation test shows that the MWCNT-NH2s/ORC gauzes have significant procoagulant activity. The hemostatic evaluation of MWCNT-NH2s/ORC composites on rabbits shows that the aminated MWCNTs increase the rate of blood stopping and hence they decrease the blood loosing from injured sites. Hemostatic evaluation indicates that the MWCNT-NH2s/ORC gauze has a valuable hemostatic performance. The products of platelets release reaction, activated platelets glycoprotein and activated clotting enzymes were increased simultaneously. The mechanism of the hemostasis for MWCNT-NH2s/ORC gauze is discussed.

Adsorption configuration of sodium 2-quinoxalinecarboxylate on iron substrate: Investigation by in situ SERS, XPS and theoretical calculation.

The adsorption geometry of sodium 2-quinoxalinecarboxylate (2-QC) on iron surface was investigated by in situ surface-enhanced Raman scattering spectroscopy (SERS) and X-ray photoelectron spectroscopy (XPS) measurements. The density functional theory (DFT) calculations predicted that 2-QC ion was a highly efficient inhibitor and N as well as O atoms were the possible adsorption centers, and theoretically offered the Raman-active band position and intensity. Potential-dependent SERS results suggested that the 2-QC strongly bonded to the iron surface via the lone pair electrons of the two O atoms of the carboxylate group in a bidentate configuration with a vertical orientation at more positive potentials; However, at -1.0 V, only one O atom of the carboxylate and the neighboring N(1) atom (or very close to surface) adsorbed on the iron surface forming an unidentate configuration with a titled orientation. The ions did not remain on the iron surface at more negative potentials.

[The effect of left bacteria in the root canal on prognosis of the root canal therapy].

OBJECTIVE: To study the effect of the left bacteria on the root canal therapy. METHODS: 50 single-rooted teeth with chronic apical periodontitis were divided into two groups, one was instrumented with step-back technique and 2.5%NaOCl ultrasonic irrigation for 3 min, then filled with Thermafil. Samples were taken after instrumentation to culture. The other was treated with traditional RCT at three visits. RESULTS: In 24 months the apical radiolucency were greatly reduced in all cases. There weren't significant relationship among the postoperative pain and the left bacteria, the degree of the obturation or the pre-operative symptoms (P > 0.05). CONCLUSION: The effect of left bacteria in root canal filled with Thermafil wasn't observed.

Association of vitamin D receptor and estrogen receptor-alpha gene polymorphism with peak bone mass and bone size in Chinese women.

AIM: To investigate if vitamin D receptor (VDR) gene Apa I polymorphism and estrogen receptor-alpha (ER-alpha) gene Pvu II, Xba I polymorphisms are related to bone mineral density (BMD), bone mineral content (BMC) and bone size in premenopausal Chinese women. METHODS: The VDR Apa I genotype and ER-alpha Pvu II, Xba I genotype were determined by PCR-restriction fragment length polymorphism (RFLP) in 493 unrelated healthy women aged 20-40 years of Han nationality in Shanghai city. BMD (g/cm(2)), BMC (g), and bone areal size (BAS, cm(2) ) at lumbar spine 1-4 (L(1-4)) and proximal femur (femoral neck, trochanter and Ward's triangle) were measured by duel-energy X-ray absorptionmetry. RESULTS: All allele frequencies did not deviate from Hardy-Weinberg equilibrium. After phenotypes were adjusted for age, height, and weight, a significant association was found between VDR Apa I genotype and BMC variation at L(1-4) and Ward's triangle (P<0.05), but not in BMD or BAS at lumbar spine and proximal femur. ER-a Pvu II, Xba I genotype was not related to BMC, BMD, and BAS at all sites. CONCLUSION: The study suggested that Apa I polymorphism in VDR gene may influence on attainment and maintenance of peak bone mass in premenopausal Chinese women.