Designing nanohesives for rapid, universal, and robust hydrogel adhesion.

Nanoparticles-based glues have recently been shown with substantial potential for hydrogel adhesion. Nevertheless, the transformative advance in hydrogel-based application places great challenges on the rapidity, robustness, and universality of achieving hydrogel adhesion, which are rarely accommodated by existing nanoparticles-based glues. Herein, we design a type of nanohesives based on the modulation of hydrogel mechanics and the surface chemical activation of nanoparticles. The nanohesives can form robust hydrogel adhesion in seconds, to the surface of arbitrary engineering solids and biological tissues without any surface pre-treatments. A representative application of hydrogel machine demonstrates the tough and compliant adhesion between dynamic tissues and sensors via nanohesives, guaranteeing accurate and stable blood flow monitoring in vivo. Combined with their biocompatibility and inherent antimicrobial properties, the nanohesives provide a promising strategy in the field of hydrogel based engineering.

[Progress in Application of Concentrated Growth Factor in Oral Tissue Regeneration].

Tissue regeneration is an important engineering method for the treatment of oral soft and hard tissue defects.Growth factors,as one of the three elements of tissue regeneration,are a necessary condition for tissue regeneration.Concentrated growth factor(CGF)is a new generation of blood extract prepared by changing the centrifugal speed on the basis of the preparation of platelet-rich plasma(PRP)and platelet-rich fibrin(PRF).It contains abundant growth factors and a fibrin matrix with a three-dimensional network structure,being capable of activating angiogenesis and promoting tissue regeneration and healing.CGF has been widely used in the repair and regeneration of oral soft and hard tissues.This paper introduces the preparation and composition of CGF and reviews the application of CGF in oral implantation and the regeneration of oral bone tissue,periodontal tissue,and dental pulp tissue.

A Study of Two Novel Techniques for One-stage Closure of Chronic Oroantral Fistula and Sinus Floor Lift.

PURPOSE: This study aimed to compare two novel techniques for chronic oroantral fistula (OAF) closure combined with maxillary sinus floor elevation. MATERIALS AND METHODS: Ten patients who had implant installation needs but suffered from a chronic OAF were enrolled in the study from January 2016 to June 2021. The technique applied involved OAF closure and simultaneous sinus floor elevation by either a transalveolar or lateral window approach. Bone graft material evaluation results, postoperative clinical symptoms and complications were compared between the two groups. Student's t -test and χ 2 test were used to analyze the results. RESULTS: In this study, 5 patients with a chronic OAF were treated with the transalveolar approach (group I), and 5 were treated with the lateral window approach (group II). The alveolar bone height was significantly higher in group II than in group I ( P ＜0.001). The pain at 1 day ( P =0.018) and 3 days ( P =0.029) postoperatively and facial swelling at 7 days ( P =0.016) postoperatively were obviously greater in group II than in group I. There were no severe complications in either group. CONCLUSIONS: The techniques combined OAF closure with sinus lifting to reduce surgical frequency and risks. The transalveolar approach resulted in milder postoperative reactions, but the lateral approach could provide more bone volume.

[Effect of rat allogeneic BMSCs-Bio-Oss-bFGF compound on tooth extraction healing: a micro-CT study].

PRUPOSE: To investigate the effect of a compound of BMSCs-Bio-Oss-bFGF on microstructure of extraction sockets in rats. METHODS: Bone mesenchymal stem cells (BMSCs) were isolated from bone marrow of 3-week SD rats by adherent method. Maxillary posterior teeth of 36 6-week SD rats were extracted and materials were implanted into sockets according to grouping. The rats were divided into 4 groups: compound group with implanting BMSCs-Bio-Oss-bFGF compound, powder group with implanting Bio-Oss, BMSCs group with implanting BMSCs, and control group without implanting any materials. The sockets were scanned by micro-CT 4 weeks, 12 weeks and 24 weeks after implantation. Two-way ANOVA was used to assess whether there was significant difference between groups with GraphPad Prism 6.0 software package. RESULTS: There was no significant difference among groups in bone mineral density (BMD), trabecular separation(Tb.Sp), trabecular thickness(Tb.Th), degree of anisotropy(DA), and trabecular number(Tb.N) 4 weeks after implantation. By 12 weeks, BMD of compound group was significantly greater than those of BMSCs group, powder group and control group (P＜0.05), and significantly greater than those of powder group and control group at 24 weeks (P＜0.05). Tb.Th of compound group was significantly greater than that of BMSCs group at 12 and 24 weeks(P＜0.05). DA had no significant difference among groups at 4, 12, and 24 weeks (P＞0.05). Tb.Sp of compound group was significantly smaller than those of powder group, BMSCs group and control group at 24 weeks(P＜0.05). Tb.N of compound group was significantly greater than those of BMSCs group and control group(P＜0.05). CONCLUSIONS: The compound of rat allogeneic BMSCs-Bio-Oss-bFGF improves socket healing.

Iron oxide nanoclusters for T 1 magnetic resonance imaging of non-human primates.

Iron-oxide-based contrast agents for magnetic resonance imaging (MRI) had been clinically approved in the United States and Europe, yet most of these nanoparticle products were discontinued owing to failures to meet rigorous clinical requirements. Significant advances have been made in the synthesis of magnetic nanoparticles and their biomedical applications, but several major challenges remain for their clinical translation, in particular large-scale and reproducible synthesis, systematic toxicity assessment, and their preclinical evaluation in MRI of large animals. Here, we report the results of a toxicity study of iron oxide nanoclusters of uniform size in large animal models, including beagle dogs and the more clinically relevant macaques. We also show that iron oxide nanoclusters can be used as T 1 MRI contrast agents for high-resolution magnetic resonance angiography in beagle dogs and macaques, and that dynamic MRI enables the detection of cerebral ischaemia in these large animals. Iron oxide nanoclusters show clinical potential as next-generation MRI contrast agents.

[The study of osteogenic differentiation in canine bone marrow stromal cell induced by point mutant type of HIF-1α].

PURPOSE: To evaluate osteogenesis in canine bone marrow mesenchymal stem cells(BMSCs) transduced by point mutant HIF-1α. METHODS: Lenti-WT (wild type HIF-1α), Lenti-MT (mutant type HIF-1α), and Lenti-LacZ (the control group) were constructed with LR recombination system. And then Lenti-LacZ, Lenti-WT and Lenti-MT were used to transduce canine BMSCs. After transduction, total RNA and protein were extracted at 0 , 1 , 4 , 7, 14 d and 21 d, respectively. The mRNA and protein expression of osteogenic factors were detected by RT-PCR and Western blot in vitro under normoxic conditions.To further prove osteogenic differentiation of HIF-1α mediated BMSCs, the BMSCs were inoculated into 6-well plate (2×10(5)/well) and then the expression of calcium nodules was measured using Alizarin red staining(ARS) at 14 d and 21 d, respectively. RESULTS: At MOI=9, the transduced efficiency of BMSCs was up to 90%. After target gene being transduced to BMSCs, the mRNA and protein expression of osteogenic factors were significantly up-regulated at 4d, reached peak at 14-21 d and maintained a state of high expression (P<0.05). ARS results showed that the target gene can induce BMSCs to the osteogenic differentiation in normoxic conditions. CONCLUSIONS: Under normoxic conditions in vitro, mutant HIF-1α can stabilize the expression and maintain a high level of activity. Lenti-MT can significantly improve the osteogenic activity of canine BMSCs.

[Construction and detection of gene expression vector of the Von Hippel-Lindau in bone marrow stromal cells].

PURPOSE: To construct siRNA-VHL expression vector and detect the effect of VHL gene interference on BMSCs. METHODS: According to the dog's VHL gene sequences, four pairs of siRNA oligo were designed and synthesized. Using vector cloning kit reorganization, four pairs of double-stranded siRNA were inserted into the expression vector (pcDNA™ 6.2-GW/EmGFPmiR) and 4 siRNA expression plasmids (SR144-1,SR144-2,SR144-3,SR144-4) were constructed. With the vector universal primers, colony PCR was screened. The positive clones were sequenced to verify whether the sequence of insert fragments in recombinant clones was consistent with oligo sequences designed or not. Interference vector transiently transfected the BMSCs. qPCR and Western blot were used to detect the gene silencing effect. In order to improve transfection efficiency of siRNA-VHL as well as the effect of the VHL gene silencing, pLenti-mi-VHL was constructed. RESULTS: Through sequencing the plasmids cloned, the fragment sequences inserted in recombinant clones were consistent with the designed oligo sequences. After 24 h and 48 h transfection of BMSCs cells by plasmids, SR144-4 showed the best effect of interference by qPCR and Western blot. Through comparing the sequencing results, the inserted fragment sequences were completely correct and the pLenti-mi-VHL was successfully constructed. CONCLUSION: The siRNA-VHL expression vector for BMSCs is successfully constructed and applicable for further experiments. Supported by Research Fund of Science and Technology Commission of Shanghai Municipality (Grant No.9411954800) and Foundation for Open Project from Shanghai Key Laboratory of Stomatology (Grant No.S30206).