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1.
International Eye Science ; (12): 44-48, 2022.
Article in Chinese | WPRIM | ID: wpr-906727

ABSTRACT

@#Vision loss can occur when the cornea loses transparency or changes shape. The most effective treatment to restore vision is to use full or partial layers of donor cornea for corneal transplantation. However, there is a severe shortage of donor corneas worldwide, with more than 98.5% of patients with corneal blindness waiting for donor corneas. In addition, there exist some problems such as the possibility of infection, allotransplantation immunologic rejection, and other problems after corneal transplantation. Therefore, tissue-engineering corneas have been widely studied over the years as a viable alternative to donor corneas, with different materials and methods. And in nearly ten years, the research has had breakthrough progress. The ultimate goal of the research is to construct a full or partial tissue-engineering graft with good transparency, biocompatibility, and appropriate mechanical strength to repair, regenerate, or replace diseased corneas. This review discusses the research progress and existing problems about the most frequently studied natural biomaterials in recent years. These biomaterials include amniotic membrane, acellular cornea, collagen, and silk. In addition to the future research directions, other challenges related to the biomaterials discussed in this field are illustrated.

2.
Rev. bras. ciênc. vet ; 28(1): 23-29, jan./mar. 2021. il.
Article in Portuguese | LILACS, VETINDEX | ID: biblio-1368354

ABSTRACT

Na procura por material alternativo no tratamento de feridas cutâneas, buscou-se com este estudo avaliar o comportamento da túnica vaginal canina conservada em glicerina a 98% como curativo biológico no tratamento de feridas cutâneas provocadas experimentalmente em ratos. Foram utilizados 16 ratos Wistar, nos quais foram induzidas experimentalmente duas lesões cutâneas na região dorsal, sendo uma cranial e a outra caudal. Uma ferida serviu de controle, a qual não recebeu tratamento, a outra recebeu a túnica vaginal recobrindo toda extensão da lesão. A seleção de qual das feridas, cranial ou caudal, iria receber a membrana foi feita de forma aleatória. Os animais foram distribuídos em quatro grupos de igual número para análises clínicas, macroscópicas e histológicas decorridos três, sete, 14 e 21 dias de pós-operatório. Na avaliação clínica e macroscópica pode-se observar que o processo de reparação teve evolução semelhante tanto no grupo controle quanto no grupo membrana. Na análise histopatológica foi constatada grande quantidade de infiltrado inflamatório nos períodos iniciais, no entanto, decorridos 21 dias, a epiderme já se encontrava reparada, e em todos os momentos foi observada maior presença de tecido conjuntivo no grupo membrana, sugerindo maior precocidade na cicatrização. Deste modo, concluiu-se que a túnica vaginal canina pode ser utilizada como nova alternativa no tratamento de feridas cutâneas.


In the search for alternative material in the treatment of cutaneous wounds, this study aimed to evaluate the behavior of canine vaginal tunic conserved in glycerin 98% as a biological dressing in the treatment of cutaneous wounds provoked experimentally in rats. Sixteen animals were used in which two cutaneous lesions were caused in the dorsal region, one cranial and the other caudal. One wound served as a control which did not receive treatment, the other received the vaginal tunic covering all extension of the lesion. The selection of which of the wounds, cranial or caudal, would receive the membrane was made at random. The animals were divided into four groups of equal numbers for clinical, macroscopic, and histological analyzes after three, seven, 14 and 21 postoperative days. In the clinical and macroscopic evaluation, it can be observed that the healing process had similar evolution in both the control group and the membrane group. In the histopathological analysis, a large amount of inflammatory infiltrate was observed in the initial periods; however, after 21 days the epidermis was already healed, and at all times a greater presence of connective tissue was observed in the membrane group, suggesting a greater precocity in healing. Thus, it was concluded that the canine vaginal tunic can be used as a new alternative in the treatment of cutaneous wounds.


Subject(s)
Animals , Rats , Wound Healing/physiology , Biological Dressings/veterinary , Rats, Wistar/injuries , Wounds and Injuries/therapy , Biocompatible Materials/therapeutic use
3.
Article in Chinese | WPRIM | ID: wpr-843031

ABSTRACT

@#Postoperative fistulae are one of the most significant complications of cleft palate repair. They usually has an adverse effect on patients’ oral hygiene, speech and even mental health. There has been a wide range of rates of fistula occurrence, from 0.8%-60%, with the classification and definition of fistulae differing from one author to the next. In this paper, the definition and classification of palatal fistulae and their reconstruction method are reviewed. At present, there is a lack of a consistent definition of palatal fistulae and a classification that can fully reflect the characteristics of palatal fistula. Adjacent flap is mainly used for repairing small fistulae with an adequate amount of surrounding tissue; anteriorly based dorsal tongue flaps are a safe and reliable method for large fistulae; free flap is beneficial for refractory and complicated palatal fistulae that are difficult to repair by the local and pedicle flap; and different synthetic materials are used in multilayer repair of fistulae; among them, composite polymer membrane is highly biocompatible, promoting cell attachment and proliferation in animal models, but its security in the human body needs further research.

4.
Article in Chinese | WPRIM | ID: wpr-888243

ABSTRACT

Ligaments are dense fibrous connective tissue that maintains joint stability through bone-to-bone connections. Ligament tears that due to sports injury or tissue aging usually require surgical intervention, and transplanting autologous, allogeneic, or artificial ligaments for reconstruction is the gold standard for treating such diseases in spite of many drawbacks. With the development of materialogy and manufacturing technology, engineered ligament tissue based on bioscaffold is expected to become a new substitute, which can lead to tissue regeneration by simulating the structure, composition, and biomechanical properties of natural tissue. This paper reviewed some recently published


Subject(s)
Animals , Bionics , Bone and Bones , Humans , Ligaments , Tissue Engineering , Wound Healing
5.
Acta Pharmaceutica Sinica ; (12): 1893-1901, 2021.
Article in Chinese | WPRIM | ID: wpr-887004

ABSTRACT

The threat of fungal diseases is increasingly rigorous. The clinically invasive fungal infections remain a main cause of morbidity and mortality in certain high-risk groups, especially in critical patients or immunocompromised patients. In drug therapy, the problems of off-target toxicity and antifungal drug resistance are still challenging. With the wide application of biomaterials and nanotechnology, more nanomedicine studies have been carried out on antifungal drugs, such as the amphotericin B liposome which greatly reduced the renal toxicity of drugs has been successfully marketed. For the unique physical and chemical properties, the nano-drug delivery system possessed great potential in improving the bioavailability, reducing the side effects of drugs, increasing the stability of drugs, and achieving cells or tissue-specificity through the modification. This review summarized the applications and limitations of antifungal drugs. Some nanomedicines were summarized in discussion oriented around the antifungal therapy, including liposomes, niosomes, lipid nanoparticles, polymer nanoparticles, microemulsion, dendrimers, inorganic nanocarriers. Nanotechnology and nano-drug delivery system provide promising strategies for the research and development of new formulations that can improve antifungal activity and possibly overcome antifungal drug resistance.

6.
Rev. cuba. invest. bioméd ; 40(supl.1): e1176, 2021. tab, graf
Article in English | LILACS, CUMED | ID: biblio-1289469

ABSTRACT

Nowadays, there is a growing interest in biodegradable polymers-based materials due to their diverse application in the biomedical field. Most studied systems involve biocompatible micro and nanodevices, such as liposomes, dendrimer, micelles or polymeric nanogels. The use of Radiation Technology, specifically gamma radiation, to produce micro and nanogels raises the possibility to obtain higher purity products, an important feature for biomedical and pharmaceutical applications. The radio-induced synthesis, characterization, cytotoxicity evaluation, and immunological response of nanogels are described in this study. Nanogel synthesis was performed in the absence of oxygen using aqueous polyvinylpyrrolidone solutions. Crosslinking reactions were carried out at 25 °C in a gamma irradiation chamber with a 60Co source. Nanogels properties were analysed by Scanning Electron Microscopy, Attenuated Total Reflection-Fourier Transform Spectroscopy, Dynamic Light Scattering, and Viscosimetry. The cytotoxicity and immunological response were evaluated by MTT test and analysis of the neutrophil respiratory burst. The results showed that nanogels formation strongly depends on the total absorbed dose. The nanogels have an elliptical shape and their chemical structure is similar to the initial polymer. The nanogels are biocompatible and promote a low-intensity neutrophil activation, similar to the well-characterized biomaterial TiO2, suggesting their potential biomedical uses(AU)


En la actualidad existe un interés creciente en los materiales biodegradables basados en polímeros, debido a sus diversas aplicaciones en la esfera de la biomedicina. En la mayoría de los sistemas estudiados participan micro- y nanodispositivos biocompatibles, tales como liposomas, dendrímeros, micelas o nanogeles poliméricos. El uso de la tecnología de radiaciones, en particular de radiaciones gamma, para producir micro- y nanogeles, eleva la posibilidad de obtener productos de mayor pureza, un rasgo importante con vistas a su aplicación biomédica y farmacéutica. El estudio describe la síntesis radioinducida, caracterización, evaluación de la citotoxicidad y respuesta inmunológica de los nanogeles. La síntesis de los nanogeles se realizó en ausencia de oxígeno, usando soluciones acuosas de polivinilpirrolidona. Las reacciones de entrecruzamiento se realizaron a 25 ºC en cámara de irradiación gamma con una fuente de 60Co. Las propiedades de los nanogeles se analizaron mediante microscopía electrónica de barrido, espectroscopia por transformada de Fourier total atenuada, dispersión dinámica de luz y viscosimetría. La citotoxicidad y la respuesta inmunológica se evaluaron mediante prueba MTT y análisis del estallido respiratorio de neutrófilos. Los resultados muestran que la formación de nanogeles depende en gran medida de la dosis total absorbida. Los nanogeles tienen forma elíptica y su estructura química es similar a la del polímero inicial. Los nanogeles son biocompatibles y promueven una activación de neutrófilos de baja intensidad similar al bien caracterizado material TiO2, lo que sugiere usos biomédicos potenciales(AU)


Subject(s)
Humans , Male , Female , Gamma Rays/therapeutic use , Nanogels/standards , Cytotoxicity Tests, Immunologic
7.
São José dos Campos; s.n; 2021. 82 p. ilus, graf, tab.
Thesis in Portuguese | LILACS, BBO | ID: biblio-1362109

ABSTRACT

Os materiais biocerâmicos são promissores em cirurgias de substituição óssea, tanto para aplicações odontológicas quanto ortopédicas. Estes materiais apresentam excelente compatibilidade biológica, osteocondutividade, degradação, além de exibirem atividade antimicrobiana. Neste presente trabalho, o objetivo foi avaliar in vitro a efetividade de scaffolds ß-fosfato tricálcico (ß-TCP) incorporado com biovidro (S53P4), produzidos por meio do processo de gel casting, na atividade celular, diferenciação osteoblástica e ação antibacteriana sobre biofilmes monotípicos, e avaliar in vivo seu efeito sobre a neoformação óssea. Os scaffolds foram confeccionados com diferentes materiais: a) ß-TCP; b) ß-TCP incorporado com biovidro. Na etapa in vitro, foram realizados os testes de MTT, proteína total, atividade de fosfatase alcalina, nódulos de mineralização, interação celular e expressão dos genes relacionados à osteogênese por RT-PCR. Na etapa in vivo, dois scaffolds de cada biomaterial foram implantados nas tíbias direita e esquerda de coelhos. Após 21 dias, os animais foram eutanasiados e a neoformação óssea foi avaliada por meio de análise histológica e análise histomorfométrica. Por fim, avaliou a formação de biofilmes em cepas de Candida albicans, Pseudomonas aeruginosa e Staphylococcus aureus. Os resultados in vitro, mostraram que os scaffolds ß-TCP/S53P4 não apresentaram efeito citotóxico e permitiram a interação de células de aspecto alongado sobre os scaffolds. Na avaliação da proteína total os scaffolds ß-TCP/S53P4 apresentaram valores mais altos, sendo significativamente maior em comparação ao ß-TCP (p<0,05) no período de 7 dias. Na atividade de fosfatase alcalina, os scaffolds foram semelhantes estatisticamente (p>0,05). Na quantificação de nódulos de mineralização, os scaffolds ß-TCP/S53P4 expressaram maior quantidade de nódulos de mineralização com diferença estatística significativa (p<0,05) com os scaffolds ß-TCP. No período de 7 dias, os genes osteopontina (Osp), fator relacionado ao Runt (Runx2), osteocalcina (Bglap), fator estimulador de colônias de macrófagos (M-csf), prostaglandina E2 (PgE2), osteonectina (Osn) e fator de crescimento de transformador Beta (Tgf-ß1) foram expressos em todos os scaffolds, sem diferença estatística entre os grupos (p>0,05). Contudo a expressão de integrina ß1 (Itg ß1) no scaffold ß-TCP foi maior do que no scaffold ß-TCP/S53P4, diferindo estatisticamente (p<0,05), houve maior expressão de colágeno I (Col-1) em ß-TCP/S53P4 com diferença estatística (p<0,05). Os defeitos preenchidos por ß-TCP/S53P4 tiveram maior formação e preenchimento por tecido ósseo neoformado (p<0,05) conforme a análise histomorfométrica. ß-TCP/S53P4 inibiu o crescimento bacteriano e fúngico em comparação ao ß-TCP (p<0,05). Desse modo, os resultados confirmam a capacidade osteogênica da cerâmica ß-TCP e sugere que após a incorporação do biovidro S53P4, pode reduzir infecções microbianas. O novo biomaterial demonstrou-se um excelente material para aplicação na engenharia de tecido ósseo.


Bioceramic materials are promising in bone replacement surgeries, both for dental and orthopedic applications. These materials have excellent biological compatibility, osteoconductivity, degradation, in addition to exhibiting antimicrobial activity. The objective of this study was to investigate the effects of bioglass (S53P4) incorporated into ß-tricalcium phosphate (ß-TCP) scaffolds on cell activity, osteoblast differentiation and antibacterial activity in monotypic biofilms in vitro, and to evaluate the influence of this new biomaterial on in vivo bone neoformation. The scaffolds were made with different materials: a) ß-TCP; b) ß-TCP incorporated with bioglass. MTT test, total protein, alkaline phosphatase activity, mineralization nodules, cell interaction and expression of genes related to osteogenesis by RT-PCR were performed. Two scaffolds of each biomaterial were implanted in the right and left tibiae of rabbits. After 21 days, the animals were euthanized and bone neoformation was evaluated through histological and histomorphometric analysis. Finally, the formation of biofilms in Candida albicans, Pseudomonas aeruginosa and Staphylococcus aureus strains. The in vitro results showed that the ß-TCP/S53P4 scaffolds did not show cytotoxic effect and allowed the interaction of elongated cells on the scaffolds. In the evaluation of total protein, the ß-TCP/S53P4 scaffolds showed better results, being significantly higher compared to ß-TCP (p<0.05) in the 7-day period. In alkaline phosphatase activity, the scaffolds were statistically similar (p>0.05). In the quantification of mineralization nodules, the ß-TCP/S53P4 scaffolds expressed a greater amount of mineralization nodules with a significant difference (p<0.05) with the ß-TCP scaffolds. Within 7 days, genes Osp, Runx2, Bglap, M-csf, PgE2, Osn and Tgf-ß1 were expressed in all scaffolds, with no significant difference between groups (p>0.05). The expression of Itg ß1 in the ß-TCP scaffold was higher than in the ß-TCP/S53P4 scaffold, differing statistically (p<0.05), but there was a higher expression of Col-1 in ß-TCP/S53P4 with statistical difference (p<0.05). In the histological analysis, neoformed bone tissue filling the defect was observed in both scaffolds, but greater formation was observed in ß-TCP/S53P4 (p<0.05). ßTCP/S53P4 inhibited bacterial and fungal growth compared to ß-TCP (p<0.05). Thus, the results confirm the osteogenic capacity of the ß-TCP ceramic and suggest that after its incorporation into the S53P4 bioglass, it can prevent microbial infections. An excellent biomaterial for application in bone tissue engineering


Subject(s)
Animals , Rabbits , Osteogenesis , Biocompatible Materials , Bone Regeneration
8.
Rev. Ateneo Argent. Odontol ; 64(1): 13-17, 2021. ilus
Article in Spanish | LILACS | ID: biblio-1248251

ABSTRACT

Se presenta un caso clínico de fractura radicular del tercio medio, de pieza 2.1 con desplazamiento de los cabos de fractura. Es tratado con un novedoso procedimiento terapéutico, mediante la utilización de un biomaterial de tercera generación osteoconductor, osteogénico y osteoinductor. Se obtiene la reparación del tejido conectivo interproximal y la formación de tejido calcificado (AU)


We present a clinical case of root fracture of the middle third, piece 2.1 with displacement of the fracture ends. It is treated with a novel therapeutic procedure, using a thirdgeneration osteoconductive, osteogenic and osteoinductive biomaterial. Interproximal connective tissue repair and calcified tissue formation are obtained (AU)


Subject(s)
Humans , Male , Adolescent , Tooth Fractures/therapy , Tooth Root/injuries , Biocompatible Materials , Regenerative Endodontics/methods , Osteogenesis , Root Canal Obturation/instrumentation , Tooth Root/diagnostic imaging , Wound Healing/physiology , Dental Fistula/radiotherapy , Dentition, Permanent
9.
Rev. Ateneo Argent. Odontol ; 64(1): 18-21, 2021. ilus
Article in Spanish | LILACS | ID: biblio-1248258

ABSTRACT

Biomaterial de tercera generación con una tasa de degradabilidad en la zona perirradicular y del foramen apical, con una velocidad similar a la que emplea el organismo para formar tejido calcificado y sellar biológicamente el extremo apical del diente. Mediante el recurso tecnológico de la microencapsulación se produce la liberación lenta y controlada de Ca2+ retenido en la superficie y en el interior de las microesferas de alginato de calcio, sin que se modifique de manera significativa las propiedades reológicas básicas del biomaterial de obturación de conductos, tales como la compresibilidad, plasticidad, extensibilidad, fluidez, viscosidad cinemática, viscosidad de compresión y endurecimiento por trabajo (AU)


Third-generation biomaterial with a degradability rate in the periradicular area and the apical foramen, with a speed similar to that used by the body to form calcified tissue and biologically seal the apical end of the tooth. Through the technological resource of microencapsulation, the slow and controlled release of Ca2+ retained on the surface and inside the calcium alginate microspheres is produced, without significantly modifying the basic rheological properties of the duct sealing biomaterial, such as compressibility, plasticity, extensibility, flowability, kinematic viscosity, compression viscosity, and work hardening (AU)


Subject(s)
Humans , Periapical Diseases/therapy , Root Canal Filling Materials/therapeutic use , Biocompatible Materials , Rheology , Calcium Compounds , Tooth Apex , Drug Compounding , Alginates/chemistry , Microspheres
10.
Article in Chinese | WPRIM | ID: wpr-848150

ABSTRACT

BACKGROUND: Polysaccharide-based biomaterials are hydrophilic and can promote cell adhesion, proliferation and differentiation. They can not only effectively prevent against oral diseases, but also promote the regeneration of periodontal ligament, enamel and alveolar bone. OBJECTIVE: To review the application of chitosan-based polysaccharide biomaterial in many oral diseases. METHODS: A computer-based online search of PubMed and CNKI databases was performed to retrieve papers regarding application of chitosan-based polysaccharide biomaterial in oral diseases with the search terms “polysaccharide (chitosan or hyaluronic acid or cellulose) and oral disease” in Chinese and English. RESULTS AND CONCLUSION: Chitosan-based polysaccharide biomaterial can be used in periodontal, oral and maxillofacial systems, aesthetic restoration, orthodontics and other fields because chitosan has aminoglucan-like structure and the biological functions of cellulose and collagen, and possesses good biocompatibility. In the early stage of the disease, polysaccharide substance can prevent the occurrence of oral diseases and inhibit the accumulation of plaque microorganisms. During the repair period of the disease, polysaccharide substance itself can promote cell proliferation and differentiation, and has a good antibacterial effect. With the help of the specific efficacy of polysaccharide biomaterials, polysaccharide can effectively exert adhesion, antibacterial and regeneration effects. In addition, polysaccharides can also be digested to monosaccharides in vivo, which is good for tissue repair. In the future therapeutic field, the degradability, biocompatibility, easy availability, specific network structure, surface charge and other characteristics of the polysaccharide can be better utilized to expand the application range.

11.
Article in Chinese | WPRIM | ID: wpr-848002

ABSTRACT

BACKGROUND: It is very difficult for urologists to choose what kind of substitute and how to reconstruct the long ureteral injuries to restore the integrity and function of the ureter. OBJECTIVE: To review recent progress and the evolution trends in the reconstruction methods of long ureteral injuries. METHODS: Relevant articles published from 1950 to 2019 were searched in PubMed, Web of Science, MEDLINE, and WanFang databases. The keywords were “ureteral injuries, ureteral replacement, biomaterial, tissue engineering, 3D bioprinting” in English and Chinese, respectively. The articles addressing ureteral replacement materials and reconstruction of ureteral injuries were selected. RESULTS AND CONCLUSION: In the reconstruction of long ureteral injury, the earliest repair method is to use autologous tissues, such as ileal, bladder muscle flap (Boari flap), and buccal mucosa graft. But such operations are difficult to avoid the damage to the surrounding tissues and organs. After that, various non-biomaterials were produced for ureteral replacement, but failed due to immune rejection and lack of peristalsis. With the development of cytology, biology and materials, the damaged tissues and organs have been regenerated by using autologous cells. Due to the development of regenerative medicine and three-dimensional printing technology, complex multi-component and multi-layered hollow tube structures that similar to their internal counterparts can be generated with three-dimensional bioprinting. But three-dimensional bioprinting cannot reconstruct the ureter and bladder with normal peristalsis and contraction function.

12.
Article in Chinese | WPRIM | ID: wpr-847915

ABSTRACT

BACKGROUND: Some studies have shown that topical application of zoledronic acid and topical application of silver nanoparticles can promote bone formation, but the difference between two methods has not been reported. OBJECTIVE: To investigate the effect of topical application of zoledronic acid versus topical application of silver nanoparticles on rabbit tooth extraction socket immediate implantation of titanium screw bonding. METHODS: Twenty-four New Zealand white rabbits were randomly divided into zoledronic acid and silver nanoparticles groups (n=12/group). After removing four incisors of the upper and lower jaws, the mixture of nanometer silver and nanometer hydroxyapatite and nanometer zoledronic acid hydroxyapatite were respectively filled in the tooth extraction pit of the two groups, and titanium screw was implanted at the same time. The isolated specimens of the upper and lower mandibles were taken at 4, 8 and 12 weeks after surgery. The data reflecting the osseointegration around the implant were obtained through gross observation, torque test, bone density test and histomorphological observation. The study was approved by the Ethical Committee of the Third Hospital of Hebei Medical University in December 2015, approval No. Z2015-021-1. RESULTS AND CONCLUSION: (1) The test results of torque mechanics showed that the average torque peak value of all titanium nails increased with the extension of time (the average value of torque peak value) and reached the maximum value at 12 weeks (the average value of torque peak value). At 4, 8 and 12 weeks after surgery, the torque peak value of titanium screw in the zoledronic acid group was higher than that in the silver nanoparticles group, and the stability of titanium screw in zoledronic acid group was better than that in silver nanoparticles group, but the difference was insignificant (P>0.05). (2) General observation and histological observation showed that at 4, 8 and 12 weeks after surgery, the hardness and structure of bone around the implants in the zoledronic acid group were significantly better than those in the silver nanoparticles group. (3) Bone mineral density analysis results showed that, at 4, 8 and 12 weeks after surgery, the gray value of bone tissue around the titanium screw in the zoledronic acid group was higher than that in the silver nanoparticles group at the same period (P>0.05). (4) These results suggest that the osseointegration of immediate implantation using nanometer zoledronic acid hydroxyapatite is better than that of the mixture of nanometer silver and nanometer hydroxyapatite.

13.
Article in Chinese | WPRIM | ID: wpr-847909

ABSTRACT

BACKGROUND: In recent years, there have been many studies on the use of supercritical fluids for biological material treatment in countries outside China. However, little is reported on application of supercritical fluids to bone tissue extraction, in particular in China. OBJECTIVE: To evaluate the effectiveness of supercritical carbon dioxide extraction technology in the treatment of porcine femur cancellous bone and its effect on bone biological properties. METHODS: Porcine femoral bone blocks that were subjected to supercritical carbon dioxide extraction (study group) or not (control group) were prepared to determine bone mineral density, microstructure, maximum compressive strength, elastic modulus, bone tissue composition, collagen content and perform histological analysis. Bone marrow mesenchymal stem cells (BMSCs) were inoculated into two groups of bone blocks, and cultured for 1 day. The microporous structure of trabecular bone and cell adhesion and growth in bone material-cell composite were observed by scanning electron microscopy. The two groups of bone blocks were implanted subcutaneously in SD rats. The inflammatory reaction of subcutaneous tissue was observed histologically at 1, 2 and 4 weeks after surgery. The experimental protocol had been approved by the Animal Ethics Committee of Chinese PLA General Hospital, China. RESULTS AND CONCLUSION: There were no significant differences in pore size, bone mineral density, maximum compressive strength, elastic modulus and collagen content between the study and control groups (P>0.05). Scanning electron microscopy showed that in the control group, the material pores had poor connectivity and there was soft tissue residue; in the study group, material pores were connected to each other and the structure was intact. Fourier transform infrared spectroscopy and X-ray diffraction analysis showed that the two groups of bone tissue materials had similar absorption and diffraction peaks. Thermogravimetric analysis showed that supercritical carbon dioxide extraction could reduce water content in bone tissue. Hematoxylin-eosin staining showed that there were no soft tissue residues in the bone, and the cell residues in the bone pit were significantly reduced in the study group, while soft tissue and cell residues were observed in the control group. Sirius red staining and modified Masson staining showed that the structure of bone collagen in the study group was intact, the cytoplasmic components reduced, and the cytoplasmic components in the control group remained significantly. Scanning electron microscopy showed that there was no obvious cell adhesion in the control group, but cell adhesion growth was obvious in the study group. Perivascular inflammatory response in the bone tissue implantation region was obviously weaker in the study group than in the study group. These results suggest that supercritical carbon dioxide extraction technology is an effective and environment-friendly bone tissue processing technology. It can effectively remove porcine cancellous bone cells and soft tissue without affecting its collagen structure and content and mechanical properties, retaining intact bone pore structure, increasing cell adhesion and growth, and effectively reducing inflammatory rejection.

14.
Article in Chinese | WPRIM | ID: wpr-792839

ABSTRACT

@#Defects in oral hard tissue caused by various factors have a negative impact on the functional and aesthetic results of prosthetic treatment. In recent years, the usage of bone tissue engineering for bone reconstruction has drawn widespread attention. Bone tissue engineering exhibits significant advantages, including the abundance of building materials and few side effects. In this paper, the composition and structure of dentin and its application in bone tissue engineering are reviewed, providing a new way to further optimize its performance. The results of a literature review show that the structure of dentin is very similar to that of autogenous bone. The inorganic component is mainly hydroxyapatite (HA), while the organic component is mainly collagen I, noncollagenous proteins (NCPs) and growth factors. Because of its unique composition, dentin can act as a scaffold and/or growth factor source through different processing methods. The deproteinization process removes most of the organic substances and creates a HA-based scaffold material with high porosity, which allows for vascularization and cellular infiltration. Demineralization increases dentin porosity by reducing the crystallinity of the mineralized components, so that part of HA, collagen fibers and growth factors are preserved. Demineralized dentin possesses various regulation functions ranging from differentiation, adhesion and proliferation of primitive cells and bone forming cell lineage. Extracted NCPs, as bioactive molecules, have been proved to play important roles that control cell differentiation, crystal nucleation and mineralization in bone formation. NCPs could be combined with variety of scaffold materials and modify their properties.

15.
Article in Chinese | WPRIM | ID: wpr-847755

ABSTRACT

BACKGROUND: Extracellular matrix can provide a living environment for different types of cells in the body and affect their biological activities, playing an important role in maintaining cell homeostasis and tissue development. OBJECTIVE: To review the research progress of extracellular matrix and its application in tissue engineering regeneration. METHODS: Databases of PubMed and CNKI were retrieved with the key words of “extracellular matrix, tissue engineering, regeneration” in English and Chinese search from 2010 to 2020, respectively. RESULTS AND CONCLUSION: The extracellular matrix contains a variety of components, and its extraction methods are diverse. It has many functions, such as guiding cells, transmitting signals, diagnosing and treating diseases, regenerating and repairing. As a precise and orderly network structure, extracellular matrix has unique advantages in tissue regeneration and repair. Extracellular matrix provides a microenvironment closest to the growth of cells in vivo, and it is rich in various active molecules, which can provide the basis for cell activity, and has a good application prospect. The forms of extracellular matrix existing in tissue regeneration are varied, and it has good biodegradability and low immunogenicity, which can also improve the inflammatory response to a certain extent, can support tissue regeneration and guide tissue reconstruction effectively. With the continuous in-depth study to extracellular matrix, its application in tissue engineering will be better developed, and it will also bring emerging technologies and treatment methods for regenerative medicine and tissue engineering in the future. However, as for the problems faced by extracellular matrix in tissue repair applications, further research and discussion are needed.

16.
Article in Chinese | WPRIM | ID: wpr-847732

ABSTRACT

BACKGROUND: Currently, it was confirmed that encapsulating islets with natural or synthetic biomaterials to form a barrier with the function of immune isolation can not only reduce the systematic use of immunosuppressive agents to a certain extent, but also make heterogenous islet transplantation possible. OBJECTIVE: To introduce the research progress of the biomaterials for islet transplantation, describe several models for encapsulating islet, and eventually discuss current research focus and prospects of islets encapsulating models. METHODS: The authors searched PubMed and Web of Science databases with the search terms “islet encapsulation, islet transplantation biomaterials, islet transplantation hydrogel” for relevant papers published. Initially, a total of 447 papers were retrieved, and 89 of them were included in the final analysis. RESULTS AND CONCLUSION: There are two main deficiencies in islet encapsulation for transplantation: one is the attack of immune rejection by the recipient; the other is the shortage of supply of oxygen and nutrient. Encapsulation of islet with a single material, synthetic or natural biomaterial, cannot address the two issues mentioned above. Herein, the biomaterial used for islet encapsulation must be modified. Current islet hydrogel models tend to combine synthetic biomaterials with natural biomaterials to take full advantage of the two kinds of biomaterials. In addition, immune-regulating drugs, angiogenic factors, or factors promoting the survival or function of islets can also be incorporated into the biomaterial. Besides, other cells can be involved to co-transplant with islets in the hydrogel. How to incorporate various strategies for addressing the above issues properly is the key of future research.

17.
Article in Chinese | WPRIM | ID: wpr-847691

ABSTRACT

BACKGROUND: Photocrosslinked alginate hydrogel has been a popular bone tissue engineering material because of its excellent biocompatibility and minimally invasive injection, but there are still problems such as insufficient strength and poor cell adhesion. OBJECTIVE: To construct the negatively charged hydrogels by introducing sodium methacrylate into photocrosslinked alginate hydrogels, and to explore the changes in its physical performance and cell adhesion. METHODS: After preparation of methacrylated alginate by reacting sodium alginate with 2-aminoethyl methacrylate, methacrylated alginate, photoinitiator and sodium methacrylate (0, 20, 40, 60 mmol/L) were homogeneously mixed. The negatively charged photocrosslinked alginate hydrogels were prepared under ultraviolet light. The functional groups of the hydrogels were analyzed by fourier transform infrared spectroscopy. The surface morphology of the hydrogels was observed by scanning electron microscopy and the swelling ratio was measured. MC3T3-E1 cells were cultured with each group of hydrogels for 48 hours, and the cytotoxicity of the hydrogels was investigated by cell counting kit-8 assay. MC3T3-E1 cells were seeded on the surface of each group of hydrogels. The early adhesion of the cells was observed by live/dead staining at the 4th hour, and cell spreading was observed on the 3rd day. RESULTS AND CONCLUSION: (1) Fourier transform infrared spectroscopy demonstrated that the introduction of sodium methacrylate could lead to a new peak at wavenumber of about 1 600 cm-1 in the hydrogel infrared wave, which was from the sodium methacrylate. (2) Scanning electron microscope observed that the density of the negatively charged photocrosslinked alginate hydrogels increased and the pore size of the gels decreased with augment of concentrations of sodium methacrylate. (3) The swelling ratio of the hydrogel decreased with the increase of the concentration of sodium methacrylate. (4) The live/dead staining revealed that the cells grew well on the surface of each hydrogel, and the cell viability reached above 95%. The cell counting kit-8 assay results showed that the negatively charged photocrosslinked alginate hydrogels had no cytotoxicity. (5) The early cell adhesion rate increased gradually and the cell extension became better with the increase of concentration of sodium methacrylate. (6) In summary, the introduction of sodium methacryl into photocrosslinked alginate hydrogels can adjust its physical properties and significantly improve its cell adhesion.

18.
Article in Chinese | WPRIM | ID: wpr-847598

ABSTRACT

BACKGROUND: Autologous bone with good biocompatibility possesses the characteristics of bone conduction, osteoinduction and osteogenesis. However, the healing process after autologous bone grafting is still controversial. The focus of controversy is whether the bone graft is completely absorbed and replaced or whether it can retain cell viability for a long time. OBJECTIVE: To observe the histological changes in bone remodeling and regeneration after cortical bone grafting. METHODS: Six healthy beagle dogs were selected as the research animals. The maxillary premolars of experimental dogs were extracted and the bone plates with width of 10 mm, length of 15 mm and thickness of 2 mm were removed from the buccal side. A bone defect model was established. The corresponding size of cortical bone block was cut on the buccal side of the bilateral mandibular body. Cortical bone grafts were fixed in the maxillary defect area. On one side pure cortical bone block was used as grafting material; on the other side the implant was placed simultaneously with the bone graft. Samples were harvested at 3 and 6 months after bone grafting. The cell survival and bone graft resorption of autologous cortical bone graft were analyzed by gross observation and histological observation. The study protocol was approved by the Animal Ethics Committee of Dalian Medical University, China. RESULTS AND CONCLUSION: The size of the grafted bone was gradually reduced, and the margin was blunt and firmly bonded to the base bone. All implants lost after 6 months. A newly formed connection between the graft and the base bone was shown by hard tissue ground sections. The porosity of bone lacuna in the grafted bone block at 6 months was significantly lower than that at 3 months (P < 0.05). The grafted bone resorption rate at 6 months was significantly higher than that at 3 months (P < 0.05). These findings indicate that osseointegration exists between grafted cortical bone block and the base bone of the recipient area. Osteocytes in the graft bone partially remain alive. With the prolongation of healing period, the proportion of new bone cells increases, and the volume of the grafted bone gradually decreases. Osseointegration of the concurrent implant is disturbed due to the absorption of cortical bone graft.

19.
Article in Chinese | WPRIM | ID: wpr-847554

ABSTRACT

BACKGROUND: There are many kinds of dressings for external use in treating pressure ulcer. Selecting a kind of dressing which is convenient, safe and effective can effectively increase the healing rate of pressure ulcer. OBJECTIVE: To evaluate the effects of five common dressings on the treatment of pressure ulcer. METHODS: A systematic search of Embase, PubMed, VIP, Elsevier, WanFang and CNKI were carried out with an end-point of July 2018. Randomized controlled trials about the therapeutic effects of different dressings on pressure ulcer were collected. All data were screened, extracted and assessed by two researchers independently. The ADDIS 1.16.8 software was adopted for data analysis. RESULTS AND CONCLUSION: A total of 24 randomized control trials (1201 patients) which involved 5 kinds of dressings were included. The results of network Meta-analysis showed that the effect of hydrocolloid dressing and foam dressing were superior to aseptic gauze and vaseline gauze in treating pressure ulcer (P 0.05). Based on the probability ranking table, the therapeutic effects of five kinds of dressl ngs in pressure ulcer were ranked as follows: hydrocolloid dressing > foam dressing > hydrogel dressing > sterile gauze > vaseline gauze. Hydrocolloid dressing and foam dressing were superior to the other dressings in the treatment of pressure ulcer.

20.
Article in Chinese | WPRIM | ID: wpr-847301

ABSTRACT

BACKGROUND: Patients with mitral valve disease have a higher incidence of atrial fibrillation after mitral valve replacement and mitral annuloplasty. Maze surgery is the gold standard for surgical treatment of atrial fibrillation. The effect of artificial valve and valve ring on maze surgery is not clear. OBJECTIVE: To evaluate the changes of sinus rhythm-left atrial contractive function after surgical maze ablation of valvular atrial fibrillation and whether valve replacement or valve ring implantation affects the recovery of sinus rhythm-left atrial contractive function. METHODS: From October 2013 to October 2017, 324 patients who underwent surgical maze ablation due to mitral valve lesions associated with persistent or long-term persistent atrial fibrillation in the General Hospital of Northern Theater Command were enrolled. All patients were treated with artificial valve replacement or artificial valve ring implantation after maze operation. The patients were followed up by electrocardiogram and echocardiography at discharge and 1, 3, 6, 12 and 24 months after procedure. A multivariate Cox analysis of predictive factors for left atrial contractive function recuperation was applied. This study was approved by the Medical Ethics Committee of General Hospital of Northern Theater Command (original General Hospital of Shenyang Military Region of Chinese PLA). RESULTS AND CONCLUSION: (1) Two patients (0.6%) died during the perioperative period, and the remaining 322 patients were followed up for 2 years. There were no adverse events related to artificial materials during the follow-up. (2) The recovery rate of left atrial contractive function increased gradually after procedure. The coexistence consistency of left atrial contractive function and sinus rhythm was good until 1 year after surgery (Kappa coefficient = 0.75, P 3 months) after surgical maze ablation (all P values 0.05). (4) ROC curve analysis showed that the optimal critical value of preoperative atrial fibrillation time and preoperative left atrial diameter for prediction of left arterial contractive function recovery was 36.5 months (sensitivity 90.5%, specificity 93.7%) and 60.5 mm (sensitivity 93.8%, specificity 85.0%) respectively. (5) These results suggest that the recovery of left atrial contractive function after surgical maze ablation is a dynamic improvement process. Early recovery of left atrial contractive function is beneficial to maintaining stable sinus rhythm in the future. Prolonged duration of atrial fibrillation, enlarged left atrial diameter, and cryoablation mode may have adverse effects on surgical maze ablation. Valve ring implantation or valvular replacement does not affect the efficacy of surgical maze ablation.

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