Research progress of intraocular lens materials / 国际眼科杂志(Guoji Yanke Zazhi)

With the wide application of phacoemulsification and intraocular lens implantation, many cataract patients have effectively recovered vision. Postoperative intraocular lens opacification is an important indicator for evaluating biocompatibility, as it affects the visual quality of patients. The manifestation and risk factors of opacification vary among different materials used for intraocular lenses. However, better visual quality after surgery is not determined by a single factor. The material of the intraocular lens and the patient's response to the intraocular lens are all factors that affect the postoperative visual quality. With the continuous advancement of technology, an increasing number of new materials are being applied in the field of intraocular lenses. Fully understanding the characteristics of intraocular lens materials, selecting suitable intraocular lens for patients and reducing complications caused by materials will be beneficial to patients. The characteristics of different intraocular lens materials and the risk factors of opacification after intraocular lens implantation were discussed in this paper.

Comparison of two obturation techniques on adhesion and proliferation of human periodontal ligament fibroblasts / Comparación de la adhesión y proliferación de fibroblastos periodontales humanos en dos técnicas de obturación endodóntica

The present study aimed to compare the adhesion and proliferation of human periodontal ligament fibroblasts (hPDL) in transverse sections of the teeth sealed with two different obturation techniques, BioRoot RCS/hydraulic obturation (HO) and AH-Plus/continuous-wave condensation (CWC). The techniques were tested using an in vitro model to simulate the interaction between periodontal tissues and the materials. The root canals were instrumented and sterilized. A total of 15 samples were obturated with BioRoot RCS/HO and 15 samples with AH-Plus/CWC. Then, roots were sectioned to obtain obturated teeth slices, and hPDL cells were seeded onto the root slices. The results were obtained at intervals of 4 and 24h for cell adhesion; and at 3,7,14, and 21 days for cell proliferation. Empty cell culture plates were use as controls. The cell adhesion was increased at 4 and 24h for both groups, with an increased response observed in the BioRoot RCS/HO group (p<0.05). The difference in cell proliferation was also found between experimental groups. After 14 days of culture, BioRoot RCS/HO group showed an increase response than control and AH-Plus/CWC groups (p<0.05), and after 21 days both groups behaved better than control group, with an increased response observed in the BioRoot RCS/HO group. This study demonstrated that both root canal sealers allow the attach and growth of periodontal ligament fibroblasts, with an increased biological response in the BioRoot RCS/HO group.

El presente estudio se enfocó en comparar la adhesión y proliferación de fibroblastos de ligamento periodontal humano (hPDL) en secciones transversales de raíces previamente obturadas con dos técnicas de obturación diferentes: obturación hidráulica empleando cono único de gutapercha y BioRoot RCS como sellador (HO), y obturación de condensación de onda continua y AH-Plus como sellador (CWC). Los selladores se usaron en un modelo in vitro que simula la interacción entre los tejidos periodontales y los materiales de obturación. Los conductos radiculares fueron instrumentados, esterilizados y obturados. La muestra se compuso de un total de 15 raíces con la técnica BioRoot RCS/HO y 15 raíces con la técnica AH-Plus/CWC. Las células de hPDL fueron sembradas en condiciones estándar de cultivo sobre las raíces seccionadas. Los resultados fueron obtenidos a intervalos de 4 y 24h para adhesión celular, y a los 3,5,7,14 y 21 días de cultivo para proliferación celular. La adhesión celular a las 4 y 24 horas mostró ser diferente para ambas técnicas en comparación con el grupo control, siendo más importante en el grupo BioRoot RCS/HO. La diferencia en la proliferación entre grupos se observó a los 14 días de cultivo, únicamente para el grupo BioRoot RCS/HO; Sin embargo para el día 21 ambas técnicas mostraron mayor proliferación celular que el grupo control, con mejor respuesta para el grupo BioRoot RCS/HO. Este estudio ha demostrado que ambos selladores de conductos permiten la adhesión y crecimiento de fibroblastos de ligamento periodontal, siendo el grupo BioRoot RCS/HO el que mostró mayor biocompatibilidad.

Biocompatibility of the Oxygenator on Pulsatile Flow by Electron Microscope

ABSTRACT Introduction: Extracorporeal perfusion flow type requires further investigation. The aim of this study is to compare the effects of pulsatile and nonpulsatile flow on oxygenator fibers that were analyzed by scanning electron microscope (SEM) and to extensively study patients' coagulation profiles, inflammatory markers, and functional blood tests. Methods: Twelve patients who had open heart surgery were randomly divided into two groups; the nonpulsatile flow (group NP, six patients) and pulsatile flow (group P, six patients) groups. Both superficial view and axial sections of the oxygenator fiber samples were examined under SEM to compare the thickness of absorbed blood proteins and amount of blood cells on the surface of oxygenators. Platelet count, coagulation profile, and inflammatory predictors were also studied from the blood samples. Results: Fibrinogen levels after cardiopulmonary bypass were significantly lower in group NP (group P, 2.57±2.78 g/L; group NP; 2.39±0.70 g/L, P=0.03). Inflammatory biomarkers such as C-reactive protein, interleukin (IL)-6, IL-12, apelin, S100β, and tumor necrosis factor alpha were comparable in both groups. Axial sections of the oxygenator fiber samples had a mean thickness of 45.2 µm and 46.5 µm in groups P and NP, respectively, and this difference is statistically significant (P=0.006). Superficial view of the fiber samples showed obviously lower platelet, leukocyte, and erythrocyte levels in group P. Conclusion: Our study demonstrated that both cellular elements and protein adsorption on oxygenator fibers are lower in the group P than in the group NP. Pulsatile perfusion has better biocompatibility on extracorporeal circulation when analyzed by SEM technique.

Orthodontic aligners: between passion and science

ABSTRACT Introduction: The benefits and safety of using orthodontic aligners have been reported more by clinical experience and expert opinion than by scientific evidence. Another important aspect is that aligners are constantly evolving. It is important to obtain evidence that allows for new updates in manufacturing technology, in the development of new movement planning protocols, in the incorporation and design of attachments, and in the aid of skeletal anchorage. Methods: Evidence retrieved from six electronic databases (CINAHL, MEDLINE, EMBASE, Psych Info, the Cochrane Library and the Joanna Briggs Library) is presented by means of questions and answers. Conclusions: There is evidence that the aligners presented different levels of difficulty in performing each type of movement, with rotational and vertical movements being the most difficult to perform. Regarding perception of pain due to tooth movement, it seems to have less impact at the beginning of treatment; but dealing with more phonoarticulatory changes seems to require more treatment time in more complex cases. Aligners do not prevent the occurrence of root resorption, although the incidence and severity of resorption may be reduced, making oral hygiene easier and accepting the risk of white spots, caries and periodontal disease. Given the conflicting evidence, the release of bisphenol-A from the aligner cannot be denied. Solutions must be found to reduce the environmental impact of aligners disposal. There is an urgent need for well-designed randomized controlled trials.

RESUMO Introdução: As vantagens e desvantagens do uso de alinhadores ortodônticos têm sido reportadas com base mais na experiência clínica e opinião de experts do que em evidências científicas. Outro aspecto importante é que os alinhadores estão em processo de evolução constante. Assim, torna-se importante obter evidências recentes, que abranjam as novas atualizações na tecnologia de confecção, no desenvolvimento de novos protocolos de planejamento para as movimentações, a incorporação e desenho dos attachments e o auxílio da ancoragem esquelética. Métodos: As evidências encontradas em seis bases de dados eletrônicas (CINAHL, MEDLINE, EMBASE, Psych Info, Biblioteca Cochrane e Biblioteca Joanna Briggs) serão apresentadas por meio de perguntas e respostas. Conclusões: Há evidências de que os alinhadores apresentam diferentes níveis de dificuldade para realizar cada tipo de movimento, sendo os movimentos rotacionais e verticais os mais difíceis de serem executados. Quanto à percepção da dor causada pela movimentação dentária, parece haver menos impacto no início do tratamento, mas os alinhadores produzem mais alterações fonoarticulatórias e parecem exigir mais tempo de tratamento em casos mais complexos. Não há evidência de diferença na estabilidade pós-tratamento, e os alinhadores não impedem a ocorrência de reabsorção radicular, apesar da incidência e a gravidade da reabsorção poderem ser menores, facilitam a higiene bucal, reduzindo o risco de manchas brancas, cáries e doenças periodontais. Dada a evidência conflitante, a liberação de bisfenol-A pelo alinhador não pode ser negada. É preciso encontrar soluções que reduzam o impacto ambiental do descarte dos alinhadores. Há uma necessidade urgente de ensaios clínicos randomizados bem desenhados.

Research progress of bio-metal organic frameworks in drug delivery system / 中国药科大学学报

@#In recent years, bio-metal organic frameworks (Bio-MOFs) synthesized with biocompatible ligands have been widely investigated as a potential drug delivery carrier due to their large specific surface area and porosity, rich host-guest intermolecular interactions, and good biocompatibility.In this review, we summarized the design methods of Bio-MOFs including structural and toxic factors, as well as a variety of drug loading methods including click chemistry, with particular focus on recent research advances in Bio-MOFs for pulmonary drug delivery systems, improving pharmaceutical properties of drugs, sustained and controlled drug release, stimulation response and targeted drug delivery systems.Finally, we summarized the bottlenecks that constrain the development of Bio-MOFs in clinical studies of actual pharmaceutical formulations and their future directions for approved formulations, aiming to provide some theoretical reference for promoting the application of Bio-MOFs in drug delivery systems.

Immune cell membrane-based biomimetic nanomedicine for treating cancer metastasis

Metastasis is the leading cause of cancer-related death. Despite extensive treatment, the prognosis for patients with metastatic cancer remains poor. In addition to conventional surgical resection, radiotherapy, immunotherapy, chemotherapy, and targeted therapy, various nanobiomaterials have attracted attention for their enhanced antitumor performance and low off-target effects. However, nanomedicines exhibit certain limitations in clinical applications, such as rapid clearance from the body, low biological stability, and poor targeting ability. Biomimetic methods utilize the natural biomembrane to mimic or hybridize nanoparticles and circumvent some of these limitations. Considering the involvement of immune cells in the tumor microenvironment of the metastatic cascade, biomimetic methods using immune cell membranes have been proposed with unique tumor-homing ability and high biocompatibility. In this review, we explore the impact of immune cells on various processes of tumor metastasis. Furthermore, we summarize the synthesis and applications of immune cell membrane-based nanocarriers increasing therapeutic efficacy against cancer metastases via immune evasion, prolonged circulation, enhanced tumor accumulation, and immunosuppression of the tumor microenvironment. Moreover, we describe the prospects and existing challenges in clinical translation.

Research progress on vesicles from Chinese medicinal herbs / 浙江大学学报·医学版

Vesicles derived from Chinese medicinal herbs (VCMH) are nano-vesicular entities released by the cells of Chinese medicinal herbs. VCMHs have various biological effects and targeting characteristics, and their component chemicals and functional activities are closely related to the parent plant. VCMH differs from animal-derived vesicles in three ways: stability, specificity, and safety. There are a number of extraction and isolation techniques for VCMH, each with their own benefits and drawbacks, and there is no unified standard. When two or more approaches are used, high quantities of intact vesicles can be obtained more quickly and efficiently. The obtained VCMHs were systematically examined and evaluated. Firstly, they are generally saucer-shaped, cup-shaped or sphere, with particle size of 10-300 nm. Secondly, they contain lipids, proteins, nucleic acids and other active substances, and these components are an important part for intercellular information transfer. Finally, they mostly have good biocompatibility and low toxicity, with anti-inflammatory, antioxidant, anti-tumor and anti-fibrotic effects. As a new drug carrier, VCMHs have outstanding active targeting capabilities, and the capsule form can effectively preserve the drugs, considerably enhancing drug delivery efficiency and stability in vitro and in vivo. The modification of its vesicular structure by suitable physical or chemical means can further create more stable and precise drug carriers. This article reviews the extraction and purification techniques, activity evaluation and application of VCMH to provide information for further research and application of new active substances and targeted drug carriers.

Preparation, characterization and biocompatibility of calcium peroxide-loaded polycaprolactone microparticles / 浙江大学学报·医学版

OBJECTIVES@#To explore the physicochemical characteristics and biocompatibility of calcium peroxide (CPO)-loaded polycaprolactone (PCL) microparticle.@*METHODS@#The CPO/PCL particles were prepared. The morphology and elemental distribution of CPO, PCL and CPO/PCL particles were observed with scanning electron microscopy and energy dispersive spectroscopy, respectively. Rat adipose mesenchymal stem cells were isolated and treated with different concentrations (0.10%, 0.25%, 0.50%, 1.00%) of CPO or CPO/PCL particles. The mesenchymal stem cells were cultured in normal media or osteogenic differentiation media under the hypoxia/normoxia conditions, and the amount of released O2 and H2O2 after CPO/PCL treatment were detected. The gene expressions of alkaline phosphatase (ALP), Runt-associated transcription factor 2 (RUNX2), osteopontin (OPN) and osteocalcin (OCN) were detected by realtime RT-PCR. SD rats were subcutaneously injected with 1.00% CPO/PCL particles and the pathological changes and infiltration of immune cells were observed with HE staining and immunohistochemistry at day 7 and day 14 after injection.@*RESULTS@#Scanning electron microscope showed that CPO particles had a polygonal structure, PCL particles were in a small spherical plastic particle state, and CPO/PCL particles had a block-like crystal structure. Energy dispersive spectroscopy revealed that PCL particles showed no calcium mapping, while CPO/PCL particles showed obvious and uniform calcium mapping. The concentrations of O2 and H2O2 released by CPO/PCL particles were lower than those of CPO group, and the oxygen release time was longer. The expressions of Alp, Runx2, Ocn and Opn increased with the higher content of CPO/PCL particles under hypoxia in osteogenic differentiation culture and normal culture, and the induction was more obvious under osteogenic differentiation conditions (all P<0.05). HE staining results showed that the muscle tissue fibers around the injection site were scattered and disorderly distributed, with varying sizes and thicknesses at day 7 after particle injection. Significant vascular congestion, widened gaps, mild interstitial congestion, local edema, inflammatory cell infiltration, and large area vacuolization were observed in some tissues of rats. At day 14 after microparticle injection, the muscle tissue around the injection site and the tissue fibers at the microparticle implantation site were arranged neatly, and the gap size was not thickened, the vascular congestion, local inflammatory cell infiltration, and vacuolization were significantly improved compared with those at day 7. The immunohistochemical staining results showed that the expressions of CD3 and CD68 positive cells significantly increased in the surrounding muscle tissue, and were densely distributed in a large area at day 7 after particle injection. At day 14 of microparticle injection, the numbers of CD3 and CD68 positive cells in peripheral muscle tissue and tissue at the site of particle implantation were lower than those at day 7 (all P<0.01).@*CONCLUSIONS@#CPO/PCL particles have good oxygen release activity, low damage to tissue, and excellent biocompatibility.

Preparation of silk fibroin/hyaluronic acid composite hydrogel based on thiol-ene click chemistry / 浙江大学学报·医学版

OBJECTIVES@#To design and prepare silk fibroin/hyaluronic acid composite hydrogel.@*METHODS@#The thiol modified silk fibroin and the double-bond modified hyaluronic acid were rapidly cured into gels through thiol-ene click polymerization under ultraviolet light condition. The grafting rate of modified silk fibroin and hyaluronic acid was characterized by 1H NMR spectroscopy; the gel point and the internal microstructure of hydrogels were characterized by rheological test and scanning electron microscopy; the mechanical properties were characterized by compression test; the swelling rate and degradation rate were determined by mass method. The hydrogel was co-cultured with the cells, the cytotoxicity was measured by the lactate dehydrogenase method, the cell adhesion was measured by the float count method, and the cell growth and differentiation on the surface of the gel were observed by scanning electron microscope and fluorescence microscope.@*RESULTS@#The functional group substitution degrees of modified silk fibroin and hyaluronic acid were 17.99% and 48.03%, respectively. The prepared silk fibroin/hyaluronic acid composite hydrogel had a gel point of 40-60 s and had a porous structure inside the gel. The compressive strength was as high as 450 kPa and it would not break after ten cycles. The water absorption capacity of the composite hydrogel was 4-10 times of its own weight. Degradation experiments showed that the hydrogel was biodegradable, and the degradation rate reached 28%-42% after 35 d. The cell biology experiments showed that the cytotoxicity of the composite gel was low, the cell adhesion was good, and the growth and differentiation of the cells on the surface of the gel were good.@*CONCLUSIONS@#The photocurable silk fibroin/hyaluronic acid composite hydrogel can form a gel quickly, and has excellent mechanical properties, adjustable swelling rate and degradation degree, good biocompatibility, so it has promising application prospects in biomedicine.

Bioactivity and biocompatibility of bioceramic sealers in endodontics: an integrative review

Introduction: Bioceramic sealers have been gaining prominence in endodontics, meaning a great advance for endodontic therapy, mainly due to their biocompatibility and bioactivity. Objectives: research and discuss the literature about the bioactivity and biocompatibility of bioceramic sealants. Materials and methods: An integrative review was performed. The systematic plan consisted of four steps. In the first stage, a bibliographic survey was carried out in the Capes Periódicos Portal database. The search criteria were articles published between 2017 and 2022, found in the "advanced search" mode, using cross-references with the following keywords: bioceramics sealers AND endodontology AND root canals AND endodontic sealer AND bioactivity AND biocompatibility. Only documents found and published in full were evaluated. In the second stage, the titles and abstracts of the articles were read. In the third stage, a selection was made of those containing 3 to 5 keywords and a wording equal to or close to the proposed keywords. The fourth step consisted of reading the texts in full, followed by checking for duplicity and building a table with the collected information. Results: In view of the research carried out, 23 articles were obtained in the first stage. After reading the titles and abstracts, 21 articles were obtained. After selecting those containing 3 to 5 keywords, 10 articles met the criteria. One article was deleted due to duplicates. 9 articles met the exclusion and inclusion criteria and were selected to be part of the integrative review. Discussion: The selected studies in this literature review showed that bioceramic endodontic sealants perform well in endodontic therapy. Conclusion: To advance in its clinical application, more in vivo and in vitro studies with precise methods are needed to obtain more reliable data about its properties.

Demineralized human dentin matrix for alveolar ridge preservation using a volumetric and histologic analyses in rats

Abstract The aim of this study was to evaluate a Demineralized Human Dentine Matrix (DHDM) as viable biomaterial for alveolar ridge preservation in a rat model. Wistar rats were submitted to the extraction of maxillary first molars bilaterally. Sockets were filled with biomaterials and divided into 4 experimental groups (n=5): blood clot, autogenous bone, bovine-derived xenograft (BDX) and DHDM. Animals were sacrificed at 7, 14 e 28 days. Microtomography (uCT) volumetric evaluation and qualitative histological analyses were performed. Results obtained through the uCT showed similar values between the DHDM and the other experimental groups. The histological evaluation demonstrated DHDM with an unspecific inflammatory process and bone neoformation with slow reabsorption of the material. This result indicates that DHDM implanted in rat sockets is biocompatible and reduces the alveolar ridge volume loss after tooth extraction.

Resumo O objetivo deste estudo foi avaliar a Matriz Dentinária Humana Desmineralizada (MDHD) como biomaterial viável para preservação do rebordo alveolar, no modelo em rato. Ratos Wistar foram submetidos à exodontias dos primeiros molares superiores bilateralmente. Os alvéolos foram preenchidos com biomateriais e divididos em 4 grupos experimentais (n=5): coágulo sanguíneo, osso autógeno, osso xenógeno de origem bovina e MDHD. Os animais foram sacrificados aos 7, 14 e 28 dias. Foram realizadas avaliações volumétricas por microtomografia (uCT) e análises histológicas qualitativas. Os resultados obtidos por meio do uCT mostraram valores semelhantes entre o MDHD e os demais grupos experimentais. A avaliação histológica demonstrou MDHD com processo inflamatório inespecífico e neoformação óssea com lenta reabsorção do material. Esse resultado indica que a MDHD implantada em alvéolo de rato é biocompatível e reduz a perda de volume do rebordo alveolar após extração dentária.

Biocompatible chitosan/polyethylene glycol/multi-walled carbon nanotube composite scaffolds for neural tissue engineering / 浙江大学学报（英文版）（B辑：生物医学和生物技术）

Carbon nanotube (CNT) composite materials are very attractive for use in neural tissue engineering and biosensor coatings. CNT scaffolds are excellent mimics of extracellular matrix due to their hydrophilicity, viscosity, and biocompatibility. CNTs can also impart conductivity to other insulating materials, improve mechanical stability, guide neuronal cell behavior, and trigger axon regeneration. The performance of chitosan (CS)/polyethylene glycol (PEG) composite scaffolds could be optimized by introducing multi-walled CNTs (MWCNTs). CS/PEG/CNT composite scaffolds with CNT content of 1%, 3%, and 5% (1%=0.01 g/mL) were prepared by freeze-drying. Their physical and chemical properties and biocompatibility were evaluated. Scanning electron microscopy (SEM) showed that the composite scaffolds had a highly connected porous structure. Transmission electron microscope (TEM) and Raman spectroscopy proved that the CNTs were well dispersed in the CS/PEG matrix and combined with the CS/PEG nanofiber bundles. MWCNTs enhanced the elastic modulus of the scaffold. The porosity of the scaffolds ranged from 83% to 96%. They reached a stable water swelling state within 24 h, and swelling decreased with increasing MWCNT concentration. The electrical conductivity and cell adhesion rate of the scaffolds increased with increasing MWCNT content. Immunofluorescence showed that rat pheochromocytoma (PC12) cells grown in the scaffolds had characteristics similar to nerve cells. We measured changes in the expression of nerve cell markers by quantitative real-time polymerase chain reaction (qRT-PCR), and found that PC12 cells cultured in the scaffolds expressed growth-associated protein 43 (GAP43), nerve growth factor receptor (NGFR), and class III β‍-tubulin (TUBB3) proteins. Preliminary research showed that the prepared CS/PEG/CNT scaffold has good biocompatibility and can be further applied to neural tissue engineering research.

Antibacterial and osteogenic properties of vancomycin/PLGA-coated porous magnesium alloy scaffolds / 中华创伤骨科杂志

Objective:To evaluate the physicochemical properties, degradation and drug release behaviour, cytocompatibility and bacteriostatic properties in vitro of porous magnesium alloy scaffolds containing vancomycin/poly(lactic-co-glycolic acid) (PLGA). Methods:Porous magnesium scaffolds (Mg-2Zn-0.3Ca) were prepared using the template replication technique. The MgF 2 surface layer was obtained by high temperature fluorination. The vancomycin/PLGA porous magnesium alloy drug-loaded scaffolds were obtained by homogeneous lifting after submersion in a dichloromethane solution of PLGA containing vancomycin hydrochloride. According to the products at each stage of the preparation (scaffolds of magnesium alloy, magnesium fluoride alloy, PLGA coated magnesium fluoride alloy, and vancomycin/PLGA magnesium fluoride alloy), they were divided into an Mg group, an MgF 2 group, a PLGA group, and a vancomycin/PLGA group. Immediately after preparation, the material science characterization, degradation rate, drug release rate, antibacterial properties, hemocompatibility, and cell proliferation and differentiation ability of the scaffolds were measured and evaluated. Results:Vancomycin-loaded magnesium alloy scaffolds were successfully prepared with an average porosity of 66.39%. Their degradation rate [(0.540±0.102) mm/year] was significantly lower than that of the Mg ones [(10.048±0.297) mm/year] ( P<0.05). Their pH of degradation in Hank equilibrium salt solution was close to the physiological pH. Their release of vancomycin was fast in the first 48 h and gradually slowed down after 48 h. Their cumulative drug concentration reached a maximum of 43 mg/L at d 11; their vancomycin was still released slowly after d 11. The antimicrobial rate in the vancomycin/PLGA group (97.89%±0.28%) was significantly higher than that in the Mg group (74.92%±2.20%), the MgF 2 group (78.46%±2.59%) and the PLGA group (61.08%±4.21%) ( P<0.05). Their hemolysis rate (0.55%) was much lower than the requirement of ISO 10993-4 (5%). The extract liquid from them promoted the proliferation of rat bone marrow mesenchymal stem cells (BMSCs), showing a gradually increased proliferation rate from d1 (104.80%±5.13%) to d3 (112.36%±2.07%) and d7 (127.79%±4.61%). The calcium nodules in BMSCs were significantly increased at d 14, with an OD value of absorbance of 1.189±0.020, significantly higher than that in the Mg group (0.803±0.020), the MgF 2 group (0.878±0.028) and the PLGA group (0.887±0.026) ( P<0.05). Conclusion:Vancomycin/PLGA-loaded porous magnesium alloy scaffolds exhibit good material properties, antibacterial properties, biocompatibility and osteogenic properties in vitro.

Experimental study on rabbit lamellar corneal transplantation with double-layer corneal stromal lens attactched by fibrin sealant / 国际眼科杂志(Guoji Yanke Zazhi)

@#AIM: To study the biocompatibility of double-layer corneal stromal lens attactched by fibrin sealant(FS)<i>in vivo</i>, and to explore the feasibility of using this material for corneal transplantation.<p>METHODS: Fifteen healthy and clean New Zealand white rabbits were selected for a self-control study. The right eye of the rabbit was used as the experimental eye and the left eye was used as the control eye. The experimental eyes used FS adhesived double-layer corneal stromal lens as the material for lamellar keratoplasty, and the control eyes did not undergo manual intervention. At 7,14, and 28d after surgery, a hand-held slit lamp was used to observe the cornea of the rabbits and then score the biocompatibility. The corneas of both eyes were taken for histopathological examination by HE staining to observe the corneal recovery at the same time.<p>RESULTS: Slit lamp observation results showed that by 28d after the operation, the corneal epithelium of the experimental eyes grew well, the degree of corneal transparency was basically restored, the degree of edema was reduced, the growth of neovascularization to the corneal edge was not aggravated, and no rejection reaction such as epithelial and endothelial rejection lines were seen; The control eyes had clear corneas and smooth corneal epithelium. The results of biocompatibility score showed that the degree of corneal implant edema gradually decreased, the transparency gradually recovered, the rejection reaction was less, and the biocompatibility of corneal implants was better in the experimental eyes after corneal transplantation. There were no differences in the degree of corneal transparency, edema and neovascularization growth between the experimental and control eyes at 28d after surgery(<i>P</i>>0.01). The results of histopathological examination showed that by 28d after corneal transplantation, there were 4-5 layers of corneal epithelial cells covering the surface of the implant in the experimental eyes, the corneal collagen was neatly and regularly arranged, no obvious inflammatory cell infiltration was seen in the implant, the boundary between the two lenses disappeared, the interlayer FS was completely absorbed by the organism, the implant was fused with the implant bed, and no obvious demarcation was seen.<p>CONCLUSION:Using FS pasted double-layer corneal stroma lens as a graft for lamellar keratoplasty has better recovery, less rejection and better biocompatibility, and can be used for lamellar keratoplasty.

Application prospect of silicon nitride ceramics in dental implants / 口腔疾病防治

@#Silicon nitride has high fracture toughness and compressive strength similar to human bone. It meets the basic mechanical requirements of implants and has good biocompatibility. The micrometer/nanometer morphology surface characteristics of silicon nitride give it good osteogenic activity and antibacterial properties, which are helpful to reduce the incidence of periimplant inflammation. Therefore, silicon nitride has good application potential in dental implants. In orthopedics, silicon nitride implants have been used in spine repair and joint implantation. However, there is a lack of research on silicon nitride as dental implant material. The evaluation of the osteogenic and antibacterial properties of silicon nitride bioceramics prepared using different sintering additives and sintering processes, the antibacterial properties of silicon nitride on different dominant oral pathogens, and the osteogenic activity and antibacterial properties of silicon nitride materials implanted into the jaw need to be further studied. Combined with the latest research results at home and abroad, this review discusses the application potential of silicon nitride materials in dentistry.

Research progress on optimization strategies for microencapsulated islet transplantation / 器官移植

Islet transplantation is one of the effective therapies for diabetes mellitus. Nevertheless, multiple issues still exist, such as shortage of donors and adverse reactions caused by long-term use of immunosuppressants, which limit the islet survival post-transplantation. Microencapsulated islet transplantation may overcome these difficulties to certain extent, whereas many factors, such as the destruction of immune isolation microenvironment within the microcapsules and insufficient supply of oxygen and nutrients, constrain the application of microencapsulated islet transplantation in clinical practice. In recent years, how to enhance the effect of microencapsulated islet transplantation has been gradually studied. The application of stem cells in microencapsulated islet transplantation has steadily become a research hot spot. Therefore, the optimizing strategies for microencapsulated islet transplantation and the application of stem cells in microencapsulated islet transplantation were reviewed, and the potential improvement techniques of microencapsulated islet transplantation were investigated in this article, aiming to provide reference for further clinical application of microencapsulated islet transplantation.

Applications of QSAR in Toxicological Risk Assessment of Medical Devices / 中国医疗器械杂志

The chemical characterization analysis of a medical device often results in chemical substances with unknown toxicities. While identification of each individual toxicity could result in a time-consuming hurdle with tremendous labor and financial burden, quantitative structure-activity relationship (QSAR) is of great significance for toxicity risk assessment of such chemical substances. By establishing quantitative relationship between the molecular structures or active groups of similar chemical compounds with their biological activities, QSAR can be utilized to predict the toxicity of such target compounds with significantly reduced cost and time. In this article, the authors generally summarized the mechanisms of QSAR approaches, current applications of QSAR modeling in the field of medical device, an introduction of the characteristics of publicly and commercially-available QSAR software, and briefly explored future trends of QSAR modeling in medical device toxicological risk assessment. The utilization of QSAR would undoubtedly further advance the toxicological risk assessment of medical devices.

Preparation and antibacterial properties of Cu-ZnO-loaded dental veneering porcelain / 口腔疾病防治

Objective@#To investigate the antibacterial properties, biocompatibility and mechanical properties of Cu-ZnO-loaded dental veneering porcelain to provide an experimental basis for the development of new dental veneering porcelain. @*Methods@#Cu-ZnO nanoparticles were added to IPS E.max Ceram for restorative veneer porcelain at different mass percentages of 0 wt%, 1 wt%, 2 wt%, 3 wt%, 4 wt%, 5 wt%, and 6 wt% using ball milling in ceramic powder. A cylindrical specimen with a diameter of 20 mm and a thickness of 2 mm was prepared by high-temperature sintering. Scanning electron microscopy was used to observe the surface morphologies of nano-Cu-ZnO and the specimens. The antibacterial effect of Escherichia coli (E. coli) was quantitatively studied by the plate colony counting method. The CCK-8 method was used to evaluate in vitro the cytotoxicity of the tested piece to mouse fibroblasts (L929). Live and dead cells were observed by fluorescence microscopy. The mechanical properties of modified IPS E. Max Ceram veneering porcelain were tested by a three-point bending strength test. @* Results @# Under the scanning electron microscope, Cu-ZnO appears with a block-like structure and can be seen dispersed in the veneering porcelain. When the nano Cu-ZnO loading was 1 wt%, 2 wt%, 3 wt%, and 4 wt%, the antibacterial rates of the specimens were 24.85%, 67.94%, 96.92%, and 99.99%, respectively, and the difference between the experimental groups and the control group was statistically significant (F = 23.308,P = 0.001). The relative growth rate of each group was greater than 80% after coculture with mouse fibroblast cells (L929) for 1 day and 3 days, and there was no significant difference between the groups. The morphology of L929 cells was normal after coculture for 24 hours. With the increase in the Cu-ZnO concentration, the flexural strength of the specimen exhibited an increasing trend followed by a decreasing trend. The bending strength of the specimen loaded with 3 wt% nano Cu-ZnO reached the maximum value (84.728 ± 6.82) MPa, and there was no statistically significant difference between groups (F = 0.633,P = 0.702).@*Conclusion@#The antibacterial rate of IPS E. max Ceram veneering porcelain loaded with 3 wt% nano Cu-ZnO was more than 96% against E. coli after high-temperature sintering at 750 ℃. The bending strength reached the maximum (84.728 ± 6.82) MPa, and there was no obvious cytotoxicity.

Biocompatibility of bioprosthetic heart valve materials with a non-glutaraldehyde-based chemical treatment / 中国胸心血管外科临床杂志

@#Objective    To study the biocompatibility of bioprosthetic heart valve material with a non-glutaraldehyde-based treatment, and to provide the safety data for the clinical application. Methods    All the tests were conducted according to GB/T16886 standards. The in vitro cytotoxicity was determined by methyl thiazolyl tetrazolium assay. Fifteen guinea pigs were divided into a test group (n=10) and a control group (n=5) in the skin sensitization test. Three New Zealand white rabbits were used in the intradermal reactivity test. Five sites on both sides of the rabbit back were set as test sites and control sites, respectively. In the acute systemic toxicity test, a total of 20 ICR mice were randomly assigned to 4 groups: a test group (polar medium), a control group (polar medium), a test group (non-polar medium) and a control group (non-polar medium), 5 in each group. Forty SD rats were divided into a test group (n=20) and a control group (n=20) in the subchronic systemic toxicity test. Results    The viability of the 100% extracts of the bioprosthetic heart valve material with a non-glutaraldehyde-based treatment was 75.2%. The rate of positive reaction was 0.0%. The total intradermal reactivity test score was 0. There was no statistical difference in the body weight between the test group and control group in the acute systemic toxicity test. There was no statistical difference in the body weight, organ weight, organ weight/body weight ratio, blood routine test or blood biochemistry between the test group and control group in the subchronic systemic toxicity test. Conclusion    The bioprosthetic heart valve material with a non-glutaraldehyde-based treatment has satisfying biocompatibility, which conforms to relevant national standards. The material might be a promising material for application in valve replacement.

Biocompatibility evaluation of electrospun PLCL/fibrinogen nanofibers in anterior cruciate ligament reconstruction / 生物医学工程学杂志

The study aimed to evaluate the safety and function of poly(lactic-acid-co-ε-caprolactone) (PLCL)/fibrinogen nanofibers (P/F-Ns), and provide theoretical basis for the clinical application. The surface morphology, mechanical properties, the hydrophilicity and the fibrinogen content of P/F-Ns were tested by scanning electron microscope, the material testing machine, the contact angle meter and the microplate reader, respectively. The cell adhesion, proliferation and ligament remodeling genes expression of Hig-82 cells on P/F-Ns were conducted through cell counting kit-8 (CCK-8) and real-time quantitative PCR analyses, respectively. The results showed that with the increase of the fibrinogen content, the pore sizes and hydrophilicity of three P/F-Ns increased, but the mechanical properties decreased. Cell adhesion and proliferation tests showed that P/F-N-2 held the best ability to promote cell adhesion and proliferation. The ligament remodeling genes expressions of Hig-82 cells on P/F-N-1, P/F-N-2 and P/F-N-3 were all up-regulated compared to P/F-N-0 on days 3 and 7. All the three P/F-Ns containing fibrinogen (P/F-N-1, P/F-N-2 and P/F-N-3) had better biocompatibility compared to P/F-N-0, and could be efficiently applied to the reconstruction of anterior cruciate ligament.