Potencial das membranas de células-tronco mesenquimais na regeneração periodontal: uma revisão sistemática de estudos pré-clínicos em modelo animal / Potential of mesenchymal stem cell sheets on periodontal regeneration: a systematic review of pre-clinical animal studies

A periodontite é uma doença inflamatória crônica multifactorial caracterizada pela destruição progressiva do aparelho de suporte periodontal. Atualmente, as técnicas convencionais para regeneração desses tecidos periodontais perdidos tiveram sucesso limitado. A tecnologia de membranas de células usando células-tronco mesenquimais apareceu como uma estratégia promissora na medicina regenerativa periodontal. Embora estudos recentes tenham mostrado o papel das membranas de células-tronco mesenquimais (MSCSs) no aumento dos tecidos de suporte dentário e ósseo, não há uma revisão sistemática focada especificamente na avaliação da regeneração periodontal em modelos animais ortotópicos. Esta revisão tem como objetivo avaliar o potencial das MSCSs na regeneração periodontal em comparação ao controle, em modelos animais experimentais. Estudos pré-clínicos em defeitos periodontais de modelos animais foram considerados elegíveis. A busca eletrônica incluiu as bases de dados MEDLINE, Web of Science, EMBASE e LILACS. Além disso, uma busca manual avaliou as revistas científicas na área de periodontia/regeneração. A revisão sistemática foi conduzida de acordo com as diretrizes de Preferred Reporting Item for Systematic Reviews and Meta-Analyses statement guidelines. A ferramenta do Centro de Revisão Sistemática para Experimentação com Animais de Laboratório (SYRCLE) foi usada para avaliar o risco de viés. Dos 3989 estudos obtidos a partir da busca no banco de dados eletrônicos foram incluídos 17 artigos. Foram empregados MSCSs autólogos, alógenos e xenógenos para melhorar a regeneração periodontal. Estes incluíram MSCSs do folículo dentário (DF), MSCSs do ligamento periodontal (PDL), MSCSs da polpa dentária (DP), MSCSs da medula óssea (BM), MSCSs periosteais alveolares (AP) e MSCSs gengivais (G). Em relação ao protocolo de indução de células, a maioria dos estudos utilizou ácido ascórbico (52,94%), outros utilizaram placas de cultura com polímero termo responsivo (47,06%). Os efeitos adversos, em relação à utilização das MSCSs no sítio doador, não foram identificados na maioria dos estudos, mesmo com o uso adjunto de scaffolds, membranas ou ambos. Meta-análise não foi considerada devido a heterogeneidades metodológicas. PDL-MSCSs demonstrou ser superior para aumento da regeneração periodontal em comparação ao controle, mas em um microambiente inflamatório induzido, DF-MSCSs foram melhores. Os DF-MSCSs parecem estar relacionados à espessura do cemento e dimensão periodontal. Além disso, DP-MSCSs e BM-MSCSs mostraram resultados melhores em comparação com o controle. Em contraste, AP-MSCSs não foram associados a melhorias na regeneração periodontal. A avaliação do risco de viés com a ferramenta da SYRCLE revelou que 44,12% dos estudos apresentavam baixo risco de viés, 55,29% foram incertos e 0,59%, alto risco. A presente revisão sistemática mostrou que as MSCSs podem aumentar a regeneração periodontal em modelos animais de defeito periodontal, fornecendo uma estratégia promissora para aumentar a regeneração periodontal.

Descelularización y regeneración de tráquea porcina: un acercamiento a la ingeniería tisular / Decellularization and Regeneration of Porcine Trachea: an Approach to Tissue Engineering

Resumen Antecedentes: la ingeniería tisular permite obtener órganos como injertos a partir de tejidos descelularizados, regenerados con células autólogas. Objetivo: descelularizar y regenerar tráqueas porcinas. Material y métodos: se descelularizaron tráqueas porcinas colocándolas cada una en el epiplón de cuatro cerdos Yorkshire para su regeneración in vivo. Una tráquea desce-lularizada con tritón (DT), descelularizada con desoxicolato (DD), descelularizada con desoxicolato y reforzada con un polímero y células epiteliales (DDR), y una nativa crio-preservada (NC). Después de 8 días se obtuvieron la DD, NC y DDR; y al día 15, la DT. Se las evaluó mecánica e histológicamente, se realizó el análisis casuístico. Resultados: las tráqueas descelularizadas conservaron la integridad del cartílago, sin diferencias mecánicas, excepto la DDR con mayor rigidez. Las tráqueas regeneradas presentaron menor rigidez, excepto la DDR que además perdió el epitelio y la vascula-ridad. Las DT, DD mostraron epitelio no respiratorio, fibrosis y vasculogénesis con in-flamación. Conclusiones: las matrices conservaron sus características mecánicas. La regenera-ción in vivo ofrece ventajas como la esterilidad, interacción celular, nutrientes; es senci-llo, factible y económico, pero no hay control del crecimiento celular y vascularización, y los tejidos presentaron alteraciones mecánicas e histológicas. El polímero impidió la re-epitelialización y revascularización. Este estudio abre la posibilidad de mejorar las me-todologías de ingeniería tisular aplicadas al tejido traqueal.

Abstract Introduction: tissue engineering makes it possible to obtain organs as grafts from de-cellularized tissues, regenerated with autologous cells.Objective: decellularize and regenerate porcine tracheas.ARTÍCULO ORIGINAL | Respirar, 2023; 15(3): 188-199 | ISSN 2953-3414 | https://doi.org/10.55720/respirar.15.3.5RECIBIDO: 9 agosto 2023ACEP TADO: 31 agosto 2023 Elisa Barrera-Ramírezhttps://orcid.org/0000-0002-2778-0882Rubén Efraín Garrido-Cardonahttps://orcid.org/0000-0001-6083-5403Alejandro Martínez-Martínezhttps://orcid.org/0000-0003-3448-910XLuis Fernando Plenge-Tellecheahttps://orcid.org/0000-0002-1619-5004Edna Rico-Escobarhttps://orcid.org/0000-0002-0933-0220Esta revista está bajo una licencia de Creative Commons Reconocimiento 4.0 Internacional. Respirar 2023; 15 (3): 189ARTÍCULO ORIGINAL / E. Barrera-Ramírez, R.E. Garrido-Cardona, A. Martínez-Martínez, L.F. Plenge-Tellechea, E. Rico-EscobarDescelularización y regeneración de tráqueaISSN 2953-3414Materials and Methods: Porcine tracheas were decellularized by placing each one in the omentum of four Yorkshire pigs for regeneration in vivo. A trachea decellularized with triton (DT), decellularized with deoxycholate (DD), decellularized with deoxycho-late and reinforced with a polymer, and epithelial cells (DDR), and a cryopreserved na-tive (NC). After 8 days, the DD, NC and DDR were obtained; and on day 15, the DT. The evaluation was mechanically and histologically, performing the case analysis.Results: the decellularized tracheas preserved the integrity of the cartilage, with no me-chanical differences, except for the DDR with greater rigidity. The regenerated trache-as presented less rigidity, except the DDR, which also lost the epithelium and vascular-ity. The DT, DD showed non-respiratory epithelium, fibrosis and vasculogenesis with inflammation.Conclusions: the matrices retained their mechanical characteristics, in vivo regenera-tion offers advantages such as sterility, cell interaction, nutrients; it is simple, feasible and economical, but there is no control of cell growth and vascularization, and the tis-sues presented mechanical and histological alterations. The polymer prevented re-epi-thelialization and revascularization. This study opens the possibility of improving tissue engineering methodologies applied to tracheal tissue.

Uso de membranas de L-PRF para aumento da espessura de tecido mole peri-implantar: um estudo longitudinal prospectivo com acompanhamento de três anos / Use of L-PRF membranes for peri-implant soft tissue thickness augmentation: a randomized clinical trial with a three-year follow-up

After the popularization of osseointegrated implants, factors related to tissue aesthetics have gained prominence within Implantology. The search for substitutes for connective tissue grafts grew and the use of leucocyte and platelet rich fibrin (L-PRF) membranes, due to their biological potential, began to gain attention. The objective of this prospective longitudinal study with 3 years of follow-up was to evaluate whether there was an increase in the thickness of the buccal mucosa in single implants in the anterior area of the maxilla with the use of three L-PRF membranes over the ridge at the time of implant installation. A sample of 27 patients, among the individuals who participated of the study and returned for a three-year follow-up, was divided into a test group (n=15), which received three L-PRF membranes inserted over the ridge, and a control group (n=12), who only received the dental implant. The thickness of the vestibular mucosa (EMV), buccal ridge defect (DVR), and height of keratinized tissue (ATQ) were evaluated, in addition to professional (PES/WES) and patientcentered (VAS) aesthetic evaluation. The results showed that the use of L-PRF membranes was not able to increase EMV in the test group after three years post- surgery. The DVR measure showed a significant reduction in the test group after three months of follow-up and was maintained at three years. And the ATQ measure showed a statistically significant reduction after three years. There was no significant difference between the groups in the 3-year postoperative follow- up regarding clinical measurements or aesthetic analyses(AU)

Com a popularização dos implantes osseointegrados, fatores relacionados à estética tecidual têm ganhado destaque dentro da Implantodontia. A busca por susbstitutos ao enxerto de tecido conjuntivo cresceu e a utilização de membranas de fibrina rica em plaquetas e leucócitos, devido ao seu potencial biológico, começou a ganhar atenção. O objetivo deste estudo longitudinal prospectivo com 3 anos de acompanhamento foi avaliar se houve aumento da espessura da mucosa vestibular em implantes unitários em área anterior de maxila com a utilização de três membranas de L-PRF sobre o rebordo concomitantemente à instalação dos implantes. Uma amostra de 27 pacientes, dentre os indivíduos que participaram do estudo e retornaram para o acompanhamento de três anos foi dividida entre grupos teste (n=15), que recebeu 3 membranas de L-PRF inseridas sobre o rebordo, e grupo controle (n=12), que recebeu apenas o implante dental. Foram avaliadas a espessura da mucosa vestibular (EMV), defeito vestibular de rebordo (DVR), e altura do tecido queratinizado (ATQ), além da avaliação estética profissional (PES/WES) e por parte dos pacientes (VAS). Os resultados mostraram que o uso das membranas de L-PRF não foi capaz de aumentar a EMV no grupo teste após três anos de acompanhamento pós-operatório. A medida DVR apresentou redução significativa no grupo teste após três meses de acompanhamento e se manteve aos três anos. E a medida ATQ apresentou redução estatisticamente significativa após três anos. Não houve diferença significativa entre os grupos no acompanhamento de 3 anos pós-operatório quanto às medidas clínicas ou em relação às análises estéticas.(AU)

Fibra de carbono ativada: avaliação das interações biológicas in vitro / Activated carbon fiber: evaluation of biological interactions in vitro

Devido a constante necessidade de desenvolver materiais biocompatíveis com propriedades osteocondutores e osteoindutoras, a presente tese conta com o desenvolvimento de dois estudos in vitro com fibra de carbono obtida a partir de fibra PAN têxtil, incorporada com diferentes íons de metais, na osteogênese com vistas à compreensão das necessidades da engenharia tecidual no desenvolvimento desse biomaterial com adequadas propriedades biológicas. As células foram obtidas dos fêmures de 09 ratos machos adultos (Wistar) pesando 300g, com 90 dias.Estudo 1: A partir da preparação da fibras foram obtidos corpos de prova de 4 mm de diâmetro e 2 mm de altura, dos seguintes grupos: fibra de carbono não ativada (FCNA), fibra carbono ativada (FCA) e fibra carbono ativada com prata (FCAAg). Após plaqueamento (n=5) em meio suplementado (MTS) e meio suplementado osteogênico (MTSO) foram analisados: viabilidade celular, conteúdo de proteína total (PT), atividade de fosfatase alcalina (ALP), interaçãocelular e formação de nódulos de mineralização. Foi avaliada a formação de biofilme nos corpos de prova, utilizando cepas de S. aureus, P. aeruginosa e E. coli. Na viabilidade celular, houve diferença estatística entre grupo controle celular (C) e FCA-MTS, FCAAg-MTS e FCAAg-MTSO. Em PT, não houvediferença, na ALP houve diferença entre C-MTS e as fibras, C-MTSO se mostrou semelhante. Em nódulos, houve diferença entre C-MTS e C-MTSO e as fibras do MTSO. Houve redução de formação de biofilme do S. aureus na FCAAg.Estudo 2: Foram obtidos corpos de prova da mesma dimensão do estudo 1 (n=5) dos seguintes grupos: fibra carbono ativada com prata (FCAAg), fibra carbono ativada com ouro (FCAAu), fibra carbono ativada com cobre (FCACu), fibra carbono ativada com paládio (FCAPd) e fibra carbono ativada com platina (FCAPt). Foram quantificadas a proliferação celular, viabilidade celular, formação de nódulos de mineralização, conteúdo de PT e ALP. Todas as amostras mostraram-se semelhantes quanto a proliferação celular, com exceção do grupo FCAAg comparado ao grupo controle (C). Sobre viabilidade celular, C obteve maior viabilidade que os outros grupos, e FCA obteve maior taxa que os grupos FCAAg, FCACu, FCAPt, sendo semelhante aos grupos FCAAu e FCAPd. Já os grupos FCAAu e FCAPd apresentaram diferença aos grupos FCAAg e FCACu. Na análise de expressão de PT apenas houve diferença entre FCA e FCAAu, sendo FCAAu com menor expressão de produção de PT. Na avaliação da ALP os grupos FCAAg e FACu mostraram diferença estatística e inferior com os grupos C, FCAAu, FCAPd e FCAPt, além disso, o grupo FCA mostrou menor taxa que C.Conclusões: As fibras utilizadas de base para a incorporação dos íons demonstraram grande potencial para uso como scaffold para reparação óssea, isso porque em ambos os estudos, na forma ativada e não ativada, as fibras apresentaram viabilidade celular e quantificação de cálcio satisfatórias. Sendo a versão não ativada mais econômica no que diz respeito ao tempo e custo de preparação. Mais estudos devem ser empregados a fim de assegurar sua segurança clínica em relação à citotoxicidade da incorporação de íons de ouro e paládio.(AU)

Due to the constant need to develop biocompatible materials with osteoconductive and osteoinductive properties, this thesis involves the development of two in vitro studies with carbon fiber obtained from textile PAN fiber, incorporated with different metal ions, in osteogenesis with a view to understanding the needs of tissue engineering in the development of this biomaterial with adequate biological properties. The cells were obtained from the femurs of 9 adult male rats (Wistar) weighing 300g, aged 90 days. Study 1: From the fiber preparation, specimens measuring 4 mm in diameter and 2 mm in height were obtained from the following groups: non-activated carbon fiber (FCNA), activated carbon fiber (FCA) and silver-activated carbon fiber (FCAAg). After plating (n=5) in supplemented medium (MTS) and supplemented osteogenic medium (MTSO), cell viability, total protein content (PT), alkaline phosphatase (ALP) activity, cell interaction and formation of mineralization nodules were analyzed. . Biofilm formation was evaluated in the specimens, using strains of S. aureus, P. aeruginosa and E. coli. In cell viability, there was a statistical difference between the cell control group (C) and FCAMTS, FCAAg-MTS and FCAAg-MTSO. In PT, there was no difference, in ALP there was a difference between C-MTS and fibers, C-MTSO was similar. In nodules, there was a difference between C-MTS and C-MTSO and MTSO fibers. There was a reduction in S. aureus biofilm formation on FCAAg. Study 2: Specimens of the same size as in study 1 (n=5) were obtained from the following groups: carbon fiber activated with silver (FCAAg), carbon fiber activated with gold (FCAAu), carbon fiber activated with copper (FCACu), palladium-activated carbon fiber (FCAPd) and platinum-activated carbon fiber (FCAPt). Cell proliferation, cell viability, formation of mineralization nodules, PT and ALP content were quantified. All samples were similar in terms of cell proliferation, with the exception of the FCAAg group compared to the control group (C). Regarding cell viability, C obtained higher viability than the other groups, and FCA obtained a higher rate than the FCAAg, FCACu, FCAPt groups, being similar to the FCAAu and FCAPd groups. The FCAAu and FCAPd groups showed differences to the FCAAg and FCACu groups. In the analysis of PT expression, there was only a difference between FCA and FCAAu, with FCAAu having lower expression of PT production. In the ALP assessment, the FCAAg and FACu groups showed a lower statistical difference compared to the C, FCAAu, FCAPd and FCAPt groups, in addition, the FCA group showed a lower rate than C. Conclusions: The fibers used as the basis for the incorporation of ions demonstrated great potential for use as a scaffold for bone repair, because in both studies, in activated and non-activated form, the fibers showed satisfactory cell viability and calcium quantification. The non-activated version is moreeconomical in terms of preparation time and cost. More studies must be carried out to ensure its clinical safety in relation to the cytotoxicity of the incorporation of gold and palladium ions. (AU)

Application of silk fibroin coatings for biomaterial surface modification: a silk road for biomedicine / 浙江大学学报（英文版）（B辑：生物医学和生物技术）

Silk fibroin (SF) as a natural biopolymer has become a popular material for biomedical applications due to its minimal immunogenicity, tunable biodegradability, and high biocompatibility. Nowadays, various techniques have been developed for the applications of SF in bioengineering. Most of the literature reviews focus on the SF-based biomaterials and their different forms of applications such as films, hydrogels, and scaffolds. SF is also valuable as a coating on other substrate materials for biomedicine; however, there are few reviews related to SF-coated biomaterials. Thus, in this review, we focused on the surface modification of biomaterials using SF coatings, demonstrated their various preparation methods on substrate materials, and introduced the latest procedures. The diverse applications of SF coatings for biomedicine are discussed, including bone, ligament, skin, mucosa, and nerve regeneration, and dental implant surface modification. SF coating is conducive to inducing cell adhesion and migration, promoting hydroxyapatite (HA) deposition and matrix mineralization, and inhibiting the Notch signaling pathway, making it a promising strategy for bone regeneration. In addition, SF-coated composite scaffolds can be considered prospective candidates for ligament regeneration after injury. SF coating has been proven to enhance the mechanical properties of the substrate material, and render integral stability to the dressing material during the regeneration of skin and mucosa. Moreover, SF coating is a potential strategy to accelerate nerve regeneration due to its dielectric properties, mechanical flexibility, and angiogenesis promotion effect. In addition, SF coating is an effective and popular means for dental implant surface modification to promote osteogenesis around implants made of different materials. Thus, this review can be of great benefit for further improvements in SF-coated biomaterials, and will undoubtedly contribute to clinical transformation in the future.

4D bioprinting technology and its application in cardiovascular tissue engineering / 生物工程学报

3D bioprinting technology is a rapidly developing technique that employs bioinks containing biological materials and living cells to construct biomedical products. However, 3D-printed tissues are static, while human tissues are in real-time dynamic states that can change in morphology and performance. To improve the compatibility between in vitro and in vivo environments, an in vitro tissue engineering technique that simulates this dynamic process is required. The concept of 4D printing, which combines "3D printing + time" provides a new approach to achieving this complex technique. 4D printing involves applying one or more smart materials that respond to stimuli, enabling them to change their shape, performance, and function under the corresponding stimulus to meet various needs. This article focuses on the latest research progress and potential application areas of 4D printing technology in the cardiovascular system, providing a theoretical and practical reference for the development of this technology.

Application of gelatin microspheres in bone tissue engineering / 生物工程学报

Gelatin microspheres were discussed as a scaffold material for bone tissue engineering, with the advantages of its porosity, biodegradability, biocompatibility, and biosafety highlighted. This review discusses how bone regeneration is aided by the three fundamental components of bone tissue engineering-seed cells, bioactive substances, and scaffold materials-and how gelatin microspheres can be employed for in vitro seed cell cultivation to ensure efficient expansion. This review also points out that gelatin microspheres are advantageous as drug delivery systems because of their multifunctional nature, which slows drug release and improves overall effectiveness. Although gelatin microspheres are useful for bone tissue creation, the scaffolds that take into account their porous structure and mechanical characteristics might be difficult to be created. This review then discusses typical techniques for creating gelatin microspheres, their recent application in bone tissue engineering, as well as possible future research directions.

Application of decellularization-recellularization technique in plastic and reconstructive surgery / 中华医学杂志(英文版)

In the field of plastic and reconstructive surgery, the loss of organs or tissues caused by diseases or injuries has resulted in challenges, such as donor shortage and immunosuppression. In recent years, with the development of regenerative medicine, the decellularization-recellularization strategy seems to be a promising and attractive method to resolve these difficulties. The decellularized extracellular matrix contains no cells and genetic materials, while retaining the complex ultrastructure, and it can be used as a scaffold for cell seeding and subsequent transplantation, thereby promoting the regeneration of diseased or damaged tissues and organs. This review provided an overview of decellularization-recellularization technique, and mainly concentrated on the application of decellularization-recellularization technique in the field of plastic and reconstructive surgery, including the remodeling of skin, nose, ears, face, and limbs. Finally, we proposed the challenges in and the direction of future development of decellularization-recellularization technique in plastic surgery.

A dual-crosslinked injectable hydrogel derived from muscular decellularized matrix promoting myoblasts proliferation and myogenic differentiation / 中国修复重建外科杂志

OBJECTIVE@#To investigate the feasibility of a dual-crosslinked injectable hydrogel derived from acellular musclar matrix (AMM) for promoting myoblasts proliferation and myogenic differentiation.@*METHODS@#Firstly, hyaluronic acid was oxidized with NaIO 4 and methylated to prepare methacrylamidated oxidized hyaluronic acid (MOHA). Then, AMM obtained by washing enzymatically treated muscle tissue was aminolyzed to prepare aminated AMM (AAMM). MOHA hydrogel and AAMM were crosslinked using Schiff based reaction and UV radiation to prepare a dual-crosslinked MOHA/AAMM injectable hydrogel. Fourier transform infrared spectroscopy (FTIR) was used to characterize MOHA, AAMM, and MOHA/AAMM hydrogels. The injectability of MOHA/AAMM hydrogel were evaluated by manual injection, and the gelation performance was assessed by UV crosslinking. The rheological properties and Young's modulus of the hydrogel were examined through mechanical tests. The degradation rate of the hydrogel was assessed by immersing it in PBS. The active components of the hydrogel were verified using immunofluorescence staining and ELISA assay kits. The promotion of cell proliferation by the hydrogel was tested using live/dead staining and cell counting kit 8 (CCK-8) assays after co-culturing with C2C12 myoblasts for 9 days. The effect of the hydrogel on myogenic differentiation was evaluated by immunofluorescence staining and real time quantitative polymerase chain reaction (RT-qPCR).@*RESULTS@#FTIR spectra confirmed the successful preparation of MOHA/AAMM hydrogel. The hydrogel exhibited good injectability and gelation ability. Compared to MOHA hydrogel, MOHA/AAMM hydrogel exhibited higher viscosity and Young's modulus, a reduced degradation rate, and contained a higher amount of collagen (including collagen type Ⅰ and collagen type Ⅲ) as well as bioactive factors (including epidermal growth factor, fibroblast growth factor 2, vascular endothelial growth factor, and insulin-like growth factor 1). The live/dead cell staining and CCK-8 assay indicated that with prolonged incubation time, there was a significant increase in viable cells and a decrease in dead cells in the C2C12 myoblasts within the MOHA/AAMM hydrogel. Compared with MOHA hydrogel, the difference was significant at each time point ( P<0.05). Immunofluorescence staining and RT-qPCR analysis demonstrated that the deposition of IGF-1 and expression levels of myogenic-related genes (including Myogenin, Troponin T, and myosin heavy chain) in the MOHA/AAMM group were significantly higher than those in the MOHA group ( P<0.05).@*CONCLUSION@#The MOHA/AAMM hydrogel prepared based on AMM can promote myoblasts proliferation and myogenic differentiation, providing a novel dual-crosslinked injectable hydrogel for muscle tissue engineering.

Bone/cartilage immunomodulating hydrogels: construction strategies and applications / 中国修复重建外科杂志

OBJECTIVE@#To review the research progress in the construction strategy and application of bone/cartilage immunomodulating hydrogels.@*METHODS@#The literature related to bone/cartilage immunomodulating hydrogels at home and abroad in recent years was reviewed and summarized from the immune response mechanism of different immune cells, the construction strategy of immunomodulating hydrogels, and their practical applications.@*RESULTS@#According to the immune response mechanism of different immune cells, the biological materials with immunoregulatory effect is designed, which can regulate the immune response of the body and thus promote the regeneration of bone/cartilage tissue. Immunomodulating hydrogels have good biocompatibility, adjustability, and multifunctionality. By regulating the physical and chemical properties of hydrogel and loading factors or cells, the immune system of the body can be purposively regulated, thus forming an immune microenvironment conducive to osteochondral regeneration.@*CONCLUSION@#Immunomodulating hydrogels can promote osteochondral repair by affecting the immunomodulation process of host organs or cells. It has shown a wide application prospect in the repair of osteochondral defects. However, more data support from basic and clinical experiments is needed for this material to further advance its clinical translation process.

Research progress in influence of microstructure on performance of triply-periodic minimal surface bone scaffolds / 中国修复重建外科杂志

OBJECTIVE@#To summarize the influence of microstructure on performance of triply-periodic minimal surface (TPMS) bone scaffolds.@*METHODS@#The relevant literature on the microstructure of TPMS bone scaffolds both domestically and internationally in recent years was widely reviewed, and the research progress in the imfluence of microstructure on the performance of bone scaffolds was summarized.@*RESULTS@#The microstructure characteristics of TPMS bone scaffolds, such as pore shape, porosity, pore size, curvature, specific surface area, and tortuosity, exert a profound influence on bone scaffold performance. By finely adjusting the above parameters, it becomes feasible to substantially optimize the structural mechanical characteristics of the scaffold, thereby effectively preempting the occurrence of stress shielding phenomena. Concurrently, the manipulation of these parameters can also optimize the scaffold's biological performance, facilitating cell adhesion, proliferation, and growth, while facilitating the ingrowth and permeation of bone tissue. Ultimately, the ideal bone fusion results will obtain.@*CONCLUSION@#The microstructure significantly and substantially influences the performance of TPMS bone scaffolds. By deeply exploring the characteristics of these microstructure effects on the performance of bone scaffolds, the design of bone scaffolds can be further optimized to better match specific implantation regions.

Differentiation of stem cells regulated by biophysical cues / 生物医学工程学杂志

Stem cells have been regarded with promising application potential in tissue engineering and regenerative medicine due to their self-renewal and multidirectional differentiation abilities. However, their fate is relied on their local microenvironment, or niche. Recent studied have demonstrated that biophysical factors, defined as physical microenvironment in which stem cells located play a vital role in regulating stem cell committed differentiation. In vitro, synthetic physical microenvironments can be used to precisely control a variety of biophysical properties. On this basis, the effect of biophysical properties such as matrix stiffness, matrix topography and mechanical force on the committed differentiation of stem cells was further investigated. This paper summarizes the approach of mechanical models of artificial physical microenvironment and reviews the effects of different biophysical characteristics on stem cell differentiation, in order to provide reference for future research and development in related fields.

A cervical cancer tissue-derived decellularized extracellular matrix scaffold for cervical cancer tissue reconstruction in vitro / 南方医科大学学报

OBJECTIVE@#The prepare decellularized extracellular matrix (ECM) scaffold materials derived from human cervical carcinoma tissues for 3D culture of cervical carcinoma cells.@*METHODS@#Fresh human cervical carcinoma tissues were treated with sodium lauryl ether sulfate (SLES) solution to prepare decellularized ECM scaffolds. The scaffolds were examined for ECM microstructure and residual contents of key ECM components (collagen, glycosaminoglycan, and elastin) and genetic materials by pathological staining and biochemical content analysis. In vitro 3D culture models were established by injecting cultured cervical cancer cells into the prepared ECM scaffolds. The cells in the recellularized scaffolds were compared with those in a conventional 2D culture system for cell behaviors including migration, proliferation and epithelial-mesenchymal transition (EMT) wsing HE staining, immunohistochemical staining and molecular biological technology analysis. Resistance to 5-fluorouracil (5-Fu) of the cells in the two culture systems was tested by analyzing the cell apoptosis rates via flow cytometry.@*RESULTS@#SLES treatment effectively removed cells and genetic materials from human cervical carcinoma tissues but well preserved the microenvironment structure and biological activity of ECM. Compared with the 2D culture system, the 3D culture models significantly promoted proliferation, migration, EMT and 5-Fu resistance of human cervical cancer cells.@*CONCLUSION@#The decellularized ECM scaffolds prepared using human cervical carcinoma tissues provide the basis for construction of in vitro 3D culture models for human cervical cancer cells.

Progress in the application of patch materials in cardiovascular surgery / 中南大学学报(医学版)

The cardiovascular patch, served as artificial graft materials to replace heart or vascular tissue defect, is still playing a key role in cardiovascular surgeries. The defects of traditional cardiovascular patch materials may determine its unsatisfactory long-term effect or fatal complications after surgery. Recent studies on many new materials (such as tissue engineered materials, three-dimensional printed materials, etc) are being developed. Patch materials have been widely used in clinical procedures of cardiovascular surgeries such as angioplasty, cardiac atrioventricular wall or atrioventricular septum repair, and valve replacement. The clinical demand for better cardiovascular patch materials is still urgent. However, the cardiovascular patch materials need to adapt to normal coagulation mechanism and durability, promote short-term endothelialization after surgery, and inhibit long-term postoperative intimal hyperplasia, its research and development process is relatively complicated. Understanding the characteristics of various cardiovascular patch materials and their application in cardiovascular surgeries is important for the selection of new clinical surgical materials and the development of cardiovascular patch materials.

Applicatoin of chitosan-based hydrogel in oral tissue engineering / 中南大学学报(医学版)

Pulpitis, periodontitis, jaw bone defect, and temporomandibular joint damage are common oral and maxillofacial diseases in clinic, but traditional treatments are unable to restore the structure and function of the injured tissues. Due to their good biocompatibility, biodegradability, antioxidant effect, anti-inflammatory activity, and broad-spectrum antimicrobial property, chitosan-based hydrogels have shown broad applicable prospects in the field of oral tissue engineering. Quaternization, carboxymethylation, and sulfonation are common chemical modification strategies to improve the physicochemical properties and biological functions of chitosan-based hydrogels, while the construction of hydrogel composite systems via carrying porous microspheres or nanoparticles can achieve local sequential delivery of diverse drugs or bioactive factors, laying a solid foundation for the well-organized regeneration of defective tissues. Chemical cross-linking is commonly employed to fabricate irreversible permanent chitosan gels, and physical cross-linking enables the formation of reversible gel networks. Representing suitable scaffold biomaterials, several chitosan-based hydrogels transplanted with stem cells, growth factors or exosomes have been used in an attempt to regenerate oral soft and hard tissues. Currently, remarkable advances have been made in promoting the regeneration of pulp-dentin complex, cementum-periodontium-alveolar bone complex, jaw bone, and cartilage. However, the clinical translation of chitosan-based hydrogels still encounters multiple challenges. In future, more in vivo clinical exploration under the conditions of oral complex microenvironments should be performed, and the combined application of chitosan-based hydrogels and a variety of bioactive factors, biomaterials, and state-of-the-art biotechnologies can be pursued in order to realize multifaceted complete regeneration of oral tissue.

Effect of pH on the chelation between strontium ions and decellularized small intestinal submucosal sponge scaffolds / 北京大学学报(医学版)

OBJECTIVE@#To investigate the preparation of decellularized small intestinal submucosa (dSIS) sponge scaffolds with chelated strontium (Sr) ions at different pH values, and to select the appropriate pH values for synthesizing Sr/dSIS scaffolds using the physicochemical properties and biocompatibility of the scaffolds as evaluation indexes.@*METHODS@#(1) Sr/dSIS scaffolds preparation and grouping: After mixing dSIS solution and strontium chloride solution in equal volumes, adjusting pH of the solution to 3, 5, 7, and 9 respectively, porous scaffolds were prepared by freeze-drying method after full reaction at 37℃, which were named Sr/dSIS-3, -5, -7, and -9 respectively, and the dSIS scaffolds were used as the control group. (2) Physicochemical property evaluation: The bulk morphology of the scaffolds was observed in each group, the microscopic morphology analyzed by scanning electron microscopy, and the porosity and pore size determined, the surface elements analyzed by energy spectroscopy, the structure of functional groups analyzed by infrared spectroscopy, the chelation rate determined by atomic spectrophotometry, the water absorption rate detected by using specific gravity method, and the compression strength evaluated by universal mechanical testing machine.(3) Biocompatibility evaluation: The cytotoxicity and proliferative effect to bone mesenchymal stem cells (BMSCs) of each group were evaluated by Calcein-AM/PI double staining method.@*RESULTS@#Scanning electron microscopy showed that the scaffolds of each group had an interconnected three-dimensional porous structure with no statistical difference in pore size and porosity. Energy spectrum analysis showed that strontium could be detected in Sr/dSIS-5, -7 and -9 groups, and strontium was uniformly distributed in the scaffolds. Functional group analysis further supported the formation of chelates in the Sr/dSIS-5, -7 and -9 groups. Chelation rate analysis showed that the Sr/dSIS-7 group had the highest strontium chelation rate, which was statistically different from the other groups (P < 0.05). The scaffolds in all the groups had good water absorption. The scaffolds in Sr/dSIS-5, -7 and -9 groups showed significantly improved mechanical properties compared with the control group (P < 0.05). The scaffolds in all the groups had good biocompatibility, and the Sr/dSIS-7 group showed the best proliferation of BMSCs.@*CONCLUSION@#When pH was 7, the Sr/dSIS scaffolds showed the highest strontium chelation rate and the best proliferation effect of BMSCs, which was the ideal pH value for the preparation of the Sr/dSIS scaffolds.

Research status and prospect of tissue engineering technology in treatment of atrophic rhinitis / 中国修复重建外科杂志

OBJECTIVE@#To review the research progress of the feasibility of a new treatment method for atrophic rhinitis (ATR) based on tissue engineering technology (seed cells, scaffold materials, and growth factors), and provide new ideas for the treatment of ATR.@*METHODS@#The literature related to ATR was extensively reviewed. Focusing on the three aspects of seed cells, scaffold materials, and growth factors, the recent research progress of ATR treatment was reviewed, and the future directions of tissue engineering technology to treat ATR were proposed.@*RESULTS@#The pathogenesis and etiology of ATR are still unclear, and the effectiveness of the current treatments are still unsatisfactory. The construction of a cell-scaffold complex with sustained and controlled release of exogenous cytokines is expected to reverse the pathological changes of ATR, promoting the regeneration of normal nasal mucosa and reconstructing the atrophic turbinate. In recent years, the research progress of exosomes, three-dimensional printing, and organoids will promote the development of tissue engineering technology for ATR.@*CONCLUSION@#Tissue engineering technology can provide a new treatment method for ATR.

Research, development and application of collagen: a review / 生物工程学报

Collagen, which widely exists in skin, bone, muscle and other tissues, is a major structural protein in mammalian extracellular matrix. It participates in cell proliferation, differentiation, migration and signal transmission, plays an important role in tissue support and repair and exerts a protective effect. Collagen is widely used in tissue engineering, clinical medicine, food industry, packaging materials, cosmetics and medical beauty due to its good biological characteristics. This paper reviews the biological characteristics of collagen and its application in bioengineering research and development in recent years. Finally, we prospect the future application of collagen as a biomimetic material.

Cell-loaded hydrogel microspheres based on droplet microfluidics: a review / 生物工程学报

Droplet microfluidics technology offers refined control over the flows of multiple fluids in micro/nano-scale, enabling fabrication of micro/nano-droplets with precisely adjustable structures and compositions in a high-throughput manner. With the combination of proper hydrogel materials and preparation methods, single or multiple cells can be efficiently encapsulated into hydrogels to produce cell-loaded hydrogel microspheres. The cell-loaded hydrogel microspheres can provide a three-dimensional, relatively independent and controllable microenvironment for cell proliferation and differentiation, which is of great value for three-dimensional cell culture, tissue engineering and regenerative medicine, stem cell research, single cell study and many other biological science fields. In this review, the preparation methods of cell-loaded hydrogel microspheres based on droplet microfluidics and its applications in biomedical field are summarized and future prospects are proposed.

Status of 3D Printing Technology for Preparing Bioceramic Materials / 中国医疗器械杂志

3D printing technology has great advantages in small batch and personalized customization, so it has attracted much attention in the biomedical field. The consumables available for 3D printing include polymer, metal, ceramic and derived materials. Biomedical ceramics, with high melting point and poor toughness, are the most difficult materials to be used in 3D printing. The progress of 3D printing ceramic preparation process using ceramic powder, ceramic slurry, ceramic wire, ceramic film and other different raw materials as consumables are reviewed, and the surface roughness, size, density and other parameters of ceramics prepared by SLS, 3DP, DIW, IJP, SL, DLP, FDM, LOM and other different processes are compared. The study also summarizes the clinical application status of 3D printed bioceramics in the field of hard tissue repair such as bone tissue engineering scaffolds and dental prostheses. The SL ceramic additive manufacturing technology based on the principle of UV polymerization has better manufacturing precision, forming quality and the ability to prepare large-size parts, and can also endow bioceramics with better biological properties, mechanical properties, antibacterial, tumor treatment and other functions by doping trace nutrients and surface functional modification. Compared with the traditional subtractive manufacturing process, the bioceramics prepared by 3D printing not only have good mechanical properties, but also often have better biocompatibility and osteoconductivity.