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1.
J Colloid Interface Sci ; 606(Pt 1): 248-260, 2022 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-34390992

RESUMO

Regulating cell behavior and function by surface topography has drawn significant attention in tissue engineering. Herein, a gradient fibrous scaffold comprising anisotropic aligned fibers and isotropic annealed fibers was developed to provide a controllable direction of cell migration, adhesion, and spreading. The electrospun aligned fibers were engraved to create surface gradients with micro-and-nanometer roughness through block copolymer (BCP) self-assembly induced by selective solvent vapor annealing (SVA). The distinct manipulation of cell behavior by annealed fibrous scaffolds with tailored self-assembled nanostructure and welded fibrous microstructure has been illustrated by in situ/ex situ small angle X-ray scattering (SAXS), scanning electron microscopy (SEM), atomic force microscopy (AFM) and in vitro cell culture. Further insights into the effect of integrated gradient fibrous scaffold were gained at the level of protein expression. From the perspective of gradient topology, this region-specific scaffold based on BCP fibers shows the prospect of guiding cell migration, adhesion and spreading and provides a generic method for designing biomaterials for tissue-engineering.


Assuntos
Engenharia Tecidual , Tecidos Suporte , Polímeros , Espalhamento a Baixo Ângulo , Difração de Raios X
2.
J Colloid Interface Sci ; 607(Pt 1): 298-311, 2022 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-34509107

RESUMO

Among three-dimensional (3D) scaffold fabrication methods, porous polymers templated using high internal phase emulsions (HIPEs) have emerged as an attractive method due to the facile generation of interconnected porosity through a variety of synthetic routes. These include a bottom-up approach to selectively incorporate nanomaterials onto the inner walls in a nonaqueous environment. In this work, novel nonaqueous HIPEs made of different (meth)acrylate monomers and a deep eutectic solvent (DES) were formulated with nonfunctionalized nanohydroxyapatite (NHA), which also played the role of cosurfactant. Free radical polymerization of HIPEs yielded free-standing nanocomposites with 3D interconnected macroporosity and nonfunctionalized NHA selectively decorating the scaffolds' inner surface. The influence of different polymer functionalities, acrylate or methacrylate, their alkyl tail length, and the presence of NHA on MC3T3-E1 preosteoblast cell proliferation in vitro, reactive oxygen species (ROS) production and alkaline phosphatase (ALP) activity were evaluated. All materials presented promising biocompatibility, non-hemolytic activity, negligible inflammatory response along to remarkably enhanced cell proliferation (e.g., up to 160-fold cell proliferation increase compared with polystyrene plate) in vitro, which open the path for the development of scaffolds in regenerative medicine. It is noteworthy that polyHIPEs studied here were obtained using a green synthetic protocol where nonfunctionalized nanoparticles can be selectively incorporated into a scaffolds' inner walls. This versatile technique allows for the simple construction of 3D bioactive nanocomposite scaffolds with varied compositions for cell culture.


Assuntos
Engenharia Tecidual , Tecidos Suporte , Proliferação de Células , Durapatita , Emulsões , Porosidade , Solventes
3.
J Assoc Physicians India ; 69(11): 11-12, 2021 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-34781610

RESUMO

AIM: Bioresorbable vascular scaffolds (BVS) over the years have emerged as a new treatment option in coronary revascularization. There is a limited data on the use of these novel devices in patients with acute myocardial infarction (AMI). The purpose of this study was to evaluate the safety feasibility and efficacy of BVS implantation in patients with AMI. METHODS AND RESULTS: 61 patients diagnosed for AMI underwent Absorb BVS device implantation. The mean age of the patients were 56.6 years with 86.89 % males. 34 patients has history of hypertension (HTN, 55.7%), 3 patients had history of myocardial infarction (MI,4.91 % ), 7 patients were diagnosed with unstable angina ( UA,11%), 34 patients had anterior wall ST elevation myocardial infarction ( AWSTEMI,55.73%),13 with ST segment elevation myocardial infarction ( STEMI,21.31%), with Killips class 2 (39.34%), 6 patients had Non ST segment Elevation Myocardial Infarction (NSTEMI, 9.83%). Procedural success was achieved in 93% patients with thrombolysis in myocardial infarction flow (TIMI) 3. During the follow up period of minimum 44±16 months no peri-procedural MACE were reported. Incidence of TLF (22.95%),definite probable ScT (11.47%) and TLR was 8 %. Average duration of DAPT was 17.57 months and 8 days. Cardiac death occurred in 4 patients (6.5%) after discharge from the hospital. CONCLUSIONS: The study results suggest that BVS implantation is feasible and safe in AMI. Specific device implantation technique is critical step towards success of BVS devices.


Assuntos
Stents Farmacológicos , Infarto do Miocárdio , Intervenção Coronária Percutânea , Implantes Absorvíveis , Feminino , Seguimentos , Humanos , Masculino , Pessoa de Meia-Idade , Infarto do Miocárdio/terapia , Tecidos Suporte , Resultado do Tratamento
5.
Eur Respir Rev ; 30(162)2021 Dec 31.
Artigo em Inglês | MEDLINE | ID: mdl-34750116

RESUMO

Effective restoration of extensive tracheal damage arising from cancer, stenosis, infection or congenital abnormalities remains an unmet clinical need in respiratory medicine. The trachea is a 10-11 cm long fibrocartilaginous tube of the lower respiratory tract, with 16-20 tracheal cartilages anterolaterally and a dynamic trachealis muscle posteriorly. Tracheal resection is commonly offered to patients suffering from short-length tracheal defects, but replacement is required when the trauma exceeds 50% of total length of the trachea in adults and 30% in children. Recently, tissue engineering (TE) has shown promise to fabricate biocompatible tissue-engineered tracheal implants for tracheal replacement and regeneration. However, its widespread use is hampered by inadequate re-epithelialisation, poor mechanical properties, insufficient revascularisation and unsatisfactory durability, leading to little success in the clinical use of tissue-engineered tracheal implants to date. Here, we describe in detail the historical attempts and the lessons learned for tracheal TE approaches by contextualising the clinical needs and essential requirements for a functional tracheal graft. TE manufacturing approaches explored to date and the clinical translation of both TE and non-TE strategies for tracheal regeneration are summarised to fully understand the big picture of tracheal TE and its impact on clinical treatment of extensive tracheal defects.


Assuntos
Engenharia Tecidual , Traqueia , Adulto , Criança , Humanos , Tecidos Suporte , Traqueia/cirurgia
6.
Sensors (Basel) ; 21(22)2021 Nov 10.
Artigo em Inglês | MEDLINE | ID: mdl-34833553

RESUMO

Bioprinting stem cells into three-dimensional (3D) scaffolds has emerged as a new avenue for regenerative medicine, bone tissue engineering, and biosensor manufacturing in recent years. Mesenchymal stem cells, such as adipose-derived and bone-marrow-derived stem cells, are capable of multipotent differentiation in a 3D culture. The use of different printing methods results in varying effects on the bioprinted stem cells with the appearance of no general adverse effects. Specifically, extrusion, inkjet, and laser-assisted bioprinting are three methods that impact stem cell viability, proliferation, and differentiation potential. Each printing method confers advantages and disadvantages that directly influence cellular behavior. Additionally, the acquisition of 3D bioprinters has become more prominent with innovative technology and affordability. With accessible technology, custom 3D bioprinters with capabilities to print high-performance bioinks are used for biosensor fabrication. Such 3D printed biosensors are used to control conductivity and electrical transmission in physiological environments. Once printed, the scaffolds containing the aforementioned stem cells have a significant impact on cellular behavior and differentiation. Natural polymer hydrogels and natural composites can impact osteogenic differentiation with some inducing chondrogenesis. Further studies have shown enhanced osteogenesis using cell-laden scaffolds in vivo. Furthermore, selective use of biomaterials can directly influence cell fate and the quantity of osteogenesis. This review evaluates the impact of extrusion, inkjet, and laser-assisted bioprinting on adipose-derived and bone-marrow-derived stem cells along with the effect of incorporating these stem cells into natural and composite biomaterials.


Assuntos
Bioimpressão , Células-Tronco Mesenquimais , Osteogênese , Impressão Tridimensional , Engenharia Tecidual , Tecidos Suporte
7.
Rev Assoc Med Bras (1992) ; 67(9): 1342-1348, 2021 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-34816932

RESUMO

OBJECTIVE: This study aimed to assess the effect of the collagen/silk fibroin scaffolds seeded with human umbilical cord-mesenchymal stem cells on functional recovery after acute complete spinal cord injury. METHODS: The fibroin and collagen were mixed (mass ratio, 3:7), and the composite scaffolds were produced. Forty rats were randomly divided into the Sham group (without spinal cord injury), spinal cord injury group (spinal cord transection without any implantation), collagen/silk fibroin scaffolds group (spinal cord transection with implantation of the collagen/silk fibroin scaffolds), and collagen/silk fibroin scaffolds + human umbilical cord-mesenchymal stem cells group (spinal cord transection with the implantation of the collagen/silk fibroin scaffolds co-cultured with human umbilical cord-mesenchymal stem cells). Motor evoked potential, Basso-Beattie-Bresnahan scale, modified Bielschowsky's silver staining, and immunofluorescence staining were performed. RESULTS: The BBB scores in the collagen/silk fibroin scaffolds + human umbilical cord-mesenchymal stem cells group were significantly higher than those in the spinal cord injury and collagen/silk fibroin scaffolds groups (p<0.05 or p<0.01). The amplitude and latency were markedly improved in the collagen/silk fibroin scaffolds + human umbilical cord-mesenchymal stem cells group compared with the spinal cord injury and collagen/silk fibroin scaffolds groups (p<0.05 or p<0.01). Meanwhile, compared to the spinal cord injury and collagen/silk fibroin scaffolds groups, more neurofilament positive nerve fiber ensheathed by myelin basic protein positive structure at the injury site were observed in the collagen/silk fibroin scaffolds + human umbilical cord-mesenchymal stem cells group (p<0.01, p<0.05). The results of Bielschowsky's silver staining indicated more nerve fibers was observed at the lesion site in the collagen/silk fibroin scaffolds + human umbilical cord-mesenchymal stem cells group compared with the spinal cord injury and collagen/silk fibroin scaffolds groups (p<0.01, p< 0.05). CONCLUSION: The results demonstrated that the transplantation of human umbilical cord-mesenchymal stem cells on a collagen/silk fibroin scaffolds could promote nerve regeneration, and recovery of neurological function after acute spinal cord injury.


Assuntos
Fibroínas , Transplante de Células-Tronco Mesenquimais , Células-Tronco Mesenquimais , Traumatismos da Medula Espinal , Animais , Colágeno , Humanos , Ratos , Recuperação de Função Fisiológica , Medula Espinal , Tecidos Suporte , Cordão Umbilical
8.
Acta Cir Bras ; 36(10): e361001, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34755757

RESUMO

PURPOSE: To evaluate methods that improve adipose-derived stem cells (ASCs) population in decellularized biological venous scaffold for tissue engineering in blood vessels, a model in rabbits. METHODS: The ASC was expanded until the third passage. Inferior vena cava (IVC) was submitted to the decellularization process using 1% sodium dodecyl sulfate (SDS) or 2% sodium deoxycholate (SD) to compose 12 study groups (G): pure SD or SDS, exposed or not to 1% TritonX-100 (TX-100) and exposed or not to poly-l'lysine and laminin (PL). Scaffolds were covered with 1 × 105 or 1 × 106 ASCs diluted in 10 µL Puramatrix™. The histological analysis was done by cell counting in hematoxylin and eosin (HE) and nuclei count in immunofluorescence (IF) with 4',6-Diamidine-2'-phenylindole dihydrochloride (DAPI). RESULTS: The study of groups in HE and IF showed similar results. For both analyses,IVC-SD-1 × 106 ASC and IVC-SD-PL-1 × 106 ASC provided the best results. The IF technique showed better sensitivity than HE, with a weak agreement between them. CONCLUSIONS: Decellularizing agent and the number of ASC influence scaffolds cellularization response and the best protocols as those ones using SD with or without the addition of PL.


Assuntos
Células-Tronco Mesenquimais , Tecido Adiposo , Animais , Coelhos , Dodecilsulfato de Sódio , Engenharia Tecidual , Tecidos Suporte
9.
Sheng Wu Gong Cheng Xue Bao ; 37(11): 4024-4035, 2021 Nov 25.
Artigo em Chinês | MEDLINE | ID: mdl-34841802

RESUMO

Decellularized extracellular matrix (dECM), which contains many proteins and growth factors, can provide three-dimensional scaffolds for cells and regulate cell regeneration. 3D bioprinting can print the combination of dECM and autologous cells layer by layer to construct the tissue structure of carrier cells. In this paper, the preparation methods of tissue and organ dECM bioink from different sources, including decellularization, crosslinking, and the application of dECM bioink in bioprinting are reviewed, with future applications prospected.


Assuntos
Bioimpressão , Engenharia Tecidual , Matriz Extracelular , Impressão Tridimensional , Tecidos Suporte
10.
Sichuan Da Xue Xue Bao Yi Xue Ban ; 52(5): 740-746, 2021 Sep.
Artigo em Chinês | MEDLINE | ID: mdl-34622586

RESUMO

Nano hydroxyapatite (nHAp), a main component of the inorganic composition of human bones and teeth, is widely used in bone tissue engineering, bone defect repair and replacement, for example, for its biocompatibility, bioactivity, bioaffinity and the ability to induce bone regeneration. Nano hydroxyapatite contains calcium and phosphorus, elements that can be replaced through the normal metabolic channels of the human body. Therefore, after implantation, it can be partially or completely absorbed and replaced by human tissues and can effectively assist bone regeneration, which makes it an ideal material for bone repair. However, traditional nHAp material is brittle and hard to be degraded in human body. In addition, nHAp has poor stability due to its high surface energy and tendency for agglomeration, which causes rapid attenuation of its mechanical strength and limits its clinical application. At present, the mechanical properties and biocompatibility of nHAp can be effectively improved by loading the related growth factors, proteins, peptides and other bioactive molecules, so as to better meet the biological requirements of bone repair materials. However, the traditional physicochemical modification methods are complicated and may interfere with the bioactivity of nHAp. It is simple to biomimetically synthesize nanomaterials by direct utilization of the molecular recognition and self-assemble capabilities of biomolecules or living microorganisms. Furthermore, the properties of the synthesized nanomaterials are stable, and the method has been extensively studied in recent years. Due to the unique crystaline structure and physicochemical properties of nHAp, results of a large number of studies have shown that its affinity with biological molecules can be used to produce bioactive nHAp by biomimetic synthesis methods. Biomimetically synthesized nHAp is expected to become the mainstream bone tissue engineering scaffold material. Analyzing and summarizing the biomimetic synthetic process and the characteristics of different nHAp materials will facilitate further development of bone defect repair materials with better mechanical and biological properties. Herein we reviewed methods of biomimetic synthesis of nHAp based on different biomolecular templates. Furthermore, we also discussed applications of biomimetic synthesized nHAp in bone tissue engineering, which can used as reference information for further research and development of new-generation bone repair biomaterials.


Assuntos
Durapatita , Engenharia Tecidual , Biomimética , Osso e Ossos , Humanos , Tecidos Suporte
11.
Soft Matter ; 17(39): 8769-8785, 2021 Oct 13.
Artigo em Inglês | MEDLINE | ID: mdl-34604877

RESUMO

Three-dimensional (3D) bioprinting has rapidly developed in the last decade, playing an increasingly important role in applications including pharmacokinetics research, tissue engineering, and organ regeneration. As a cutting-edge technology in 3D printing, gel bath-supported 3D bioprinting enables the freeform construction of complex structures with soft and water-containing materials, facilitating the in vitro fabrication of live tissue or organ models. To realize in vivo-like organs or tissues in terms of biological functions and complex structures by 3D printing, high resolution and fidelity are prerequisites. Although a wide range of gel matrices have recently been developed as supporting materials, the effect of bath properties and printing parameters on the print resolution is still not clearly understood. This review systematically introduces the decisive factors for resolution in both bulk gel bath systems and granular microgel bath systems, providing guidelines for high-resolution 3D bioprinting based on bath properties and printing parameters.


Assuntos
Bioimpressão , Microgéis , Banhos , Impressão Tridimensional , Engenharia Tecidual , Tecidos Suporte
12.
Zhongguo Xiu Fu Chong Jian Wai Ke Za Zhi ; 35(10): 1303-1310, 2021 Oct 15.
Artigo em Chinês | MEDLINE | ID: mdl-34651485

RESUMO

Objective: To evaluate the physical and chemical properties, immunogenicity, and osteogenesis of two antigen-extracted xenogeneic bone scaffolds-decalcified bone matrix (DBM) and calcined bone. Methods: By removing the inorganic and organic components of adult pig femus, xenogeneic DBM and calcined bone were prepared respectively. The density and pH value of the two materials were measured and calculated, the material morphology and pore diameter were observed by scanning electron microscope, and the surface contact angle was measured by automatic contact angle measuring instrument. The safety, osteogenic activity, and immunogenicity of the two materials were evaluated by cytotoxicity test, osteoblast proliferation test, DNA residue test, and human peripheral blood lymphocyte proliferation test. The two materials were implanted into the 5 mm full-thickness skull defect of 6-week-old male Sprague Dawley rats (the blank control group was not implanted with materials). The materials were taken at 4 and 8 weeks after operation, the repair effect of the materials on the rat skull was observed and evaluated by gross observation, Micro-CT scanning, and HE staining observation. Results: Compared with calcined bone, DBM has lower density and poor hydrophilicity; the pH value of the two materials was 5.5-6.1, and the pore diameter was 160-800 µm. The two materials were non-cytotoxic and could promote the proliferation of osteoblasts. The absorbance ( A) values of osteoblast proliferation at 1, 4, and 7 days in the DBM group were significantly higher than those in the calcined bone group ( P<0.05). The DNA residues of the two materials were much lower than 50 ng/mg dry weight, and neither of them could stimulate the proliferation and differentiation of human peripheral blood lymphocytes. The results of animal experiments in vivo showed that the bone volume/total volume (BV/TV) in DBM group and calcined bone group were significantly higher than that in blank control group at 4 weeks after operation ( P<0.05), and that in calcined bone group was significantly higher than that in DBM group ( P<0.05); at 8 weeks after operation, there was no significant difference in BV/TV between groups ( P>0.05). HE staining showed that at 4 and 8 weeks after operation, the defect in the blank control group was filled with fibrous connective tissue, the defect was obvious, and no bone growth was found; the defect in DBM group and calcined bone group had been repaired to varying degrees, and a large number of new bone formation could be seen. The material degradability of DBM group was better than that of calcined bone group. Conclusion: The physical and chemical properties and degradability of the two kinds of xenogeneic bone scaffolds were slightly different, both of them have no immunogenicity and can promote the repair and reconstruction of skull defects in rats.


Assuntos
Matriz Óssea , Osteogênese , Animais , Diferenciação Celular , Masculino , Ratos , Ratos Sprague-Dawley , Crânio , Suínos , Tecidos Suporte
13.
Biomed Mater Eng ; 32(6): 375-381, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34633315

RESUMO

BACKGROUND: An increasing number of bone graft materials are commercially available and vary in their composition, mechanism of action, costs, and indications. OBJECTIVE: A commercially available PLGA scaffold produced using 3D printing technology has been used to promote the preservation of the alveolar socket after tooth extraction. We examined its influence on bone regeneration in long bones of New Zealand White rabbits. METHODS: 5.0-mm-diameter circular defects were created on the tibia bones of eight rabbits. Two groups were studied: (1) control group, in which the bone defects were left empty; (2) scaffold group, in which the PLGA scaffolds were implanted into the bone defect. Radiography was performed every two weeks postoperatively. After sacrifice, bone specimens were isolated and examined by micro-computed tomography and histology. RESULTS: Scaffolds were not degraded by eight weeks after surgery. Micro-computed tomography and histology showed that in the region of bone defects that was occupied by scaffolds, bone regeneration was compromised and the total bone volume/total volume ratio (BV/TV) was significantly lower. CONCLUSION: The implantation of this scaffold impedes bone regeneration in a non-critical bone defect. Implantation of bone scaffolds, if unnecessary, lead to a slower rate of fracture healing.


Assuntos
Tíbia , Tecidos Suporte , Animais , Regeneração Óssea , Glicolatos , Glicóis , Impressão Tridimensional , Coelhos , Tíbia/diagnóstico por imagem , Tíbia/cirurgia , Microtomografia por Raio-X
14.
ACS Biomater Sci Eng ; 7(11): 5288-5300, 2021 11 08.
Artigo em Inglês | MEDLINE | ID: mdl-34661396

RESUMO

Reinforced extracellular matrix (ECM)-based hydrogels recapitulate several mechanical and biochemical features found in the tumor microenvironment (TME) in vivo. While these gels retain several critical structural and bioactive molecules that promote cell-matrix interactivity, their mechanical properties tend toward the viscous regime limiting their ability to retain ordered structural characteristics when considered as architectured scaffolds. To overcome this limitation characteristic of pure ECM hydrogels, we present a composite material containing alginate, a seaweed-derived polysaccharide, and gelatin, denatured collagen, as rheological modifiers which impart mechanical integrity to the biologically active decellularized ECM (dECM). After an optimization process, the reinforced gel proposed is mechanically stable and bioprintable and has a stiffness within the expected physiological values. Our hydrogel's elastic modulus has no significant difference when compared to tumors induced in preclinical xenograft head and neck squamous cell carcinoma (HNSCC) mouse models. The bioprinted cell-laden model is highly reproducible and allows proliferation and reorganization of HNSCC cells while maintaining cell viability above 90% for periods of nearly 3 weeks. Cells encapsulated in our bioink produce spheroids of at least 3000 µm2 of cross-sectional area by day 15 of culture and are positive for cytokeratin in immunofluorescence quantification, a common marker of HNSCC model validation in 2D and 3D models. We use this in vitro model system to evaluate the standard-of-care small molecule therapeutics used to treat HNSCC clinically and report a 4-fold increase in the IC50 of cisplatin and an 80-fold increase for 5-fluorouracil compared to monolayer cultures. Our work suggests that fabricating in vitro models using reinforced dECM provides a physiologically relevant system to evaluate malignant neoplastic phenomena in vitro due to the physical and biological features replicated from the source tissue microenvironment.


Assuntos
Bioimpressão , Animais , Matriz Extracelular , Hidrogéis , Camundongos , Impressão Tridimensional , Engenharia Tecidual , Tecidos Suporte
15.
Biomater Sci ; 9(22): 7575-7590, 2021 Nov 09.
Artigo em Inglês | MEDLINE | ID: mdl-34665185

RESUMO

This work describes the preparation, characterization and functionalization with magnetic nanoparticles of a bone tissue-mimetic scaffold composed of collagen and hydroxyapatite obtained through a biomineralization process. Bone remodeling takes place over several weeks and the possibility to follow it in vivo in a quick and reliable way is still an outstanding issue. Therefore, this work aims to produce an implantable material that can be followed in vivo during bone regeneration by using the existing non-invasive imaging techniques (MRI). To this aim, suitably designed biocompatible SPIONs were linked to the hybrid scaffold using two different strategies, one involving naked SPIONs (nMNPs) and the other using coated and activated SPIONs (MNPs) exposing carboxylic acid functions allowing a covalent attachment between MNPs and collagen molecules. Physico-chemical characterization was carried out to investigate the morphology, crystallinity and stability of the functionalized materials followed by MRI analyses and evaluation of a radiotracer uptake ([99mTc]Tc-MDP). Cell proliferation assays in vitro were carried out to check the cytotoxicity and demonstrated no side effects due to the SPIONs. The achieved results demonstrated that the naked and coated SPIONs are more homogeneously distributed in the scaffold when incorporated during the synthesis process. This work demonstrated a suitable approach to develop a biomaterial for bone regeneration that allows the monitoring of the healing progress even for long-term follow-up studies.


Assuntos
Regeneração Óssea , Tecidos Suporte , Osso e Ossos/diagnóstico por imagem , Colágeno , Durapatita
16.
ACS Biomater Sci Eng ; 7(11): 5007-5013, 2021 11 08.
Artigo em Inglês | MEDLINE | ID: mdl-34677053

RESUMO

In vitro models provide a good starting point for drug screening and understanding various cellular mechanisms corresponding to different conditions. 3D cultures have drawn significant interest to mimic the in vivo microenvironment better and overcome the limitations of the 2D monolayered cultures. We previously reported a technique based on the screen printing process to pattern live mammalian cells using gelatin as the bioink. Even though gelatin is an inexpensive scaffolding material with various tissue engineering applications, it might not be the ideal hydrogel material to provide various mechanical and chemical cues to the cells. In this paper, we discuss the synthesis and characterization of two synthetic chemically cross-linked hydrogel systems based on poly(ethylene glycol) (PEG) and poly-l-lysine (PLL) to be used as the bioink in the screen printing process. These hydrogels are suitable as the bioinks for the screen printing process and serve as the barebone materials that can be tuned mechanically and augmented chemically to create a suitable in vitro microenvironment for the cells. This paper presents the synthesis, mechanical testing, and characterization of the hydrogel systems and their applications in the screen printing process.


Assuntos
Bioimpressão , Hidrogéis , Animais , Impressão Tridimensional , Engenharia Tecidual , Tecidos Suporte
17.
J Biomed Nanotechnol ; 17(10): 2014-2020, 2021 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-34706801

RESUMO

MXene has attracted tremendous attention due to its outstanding photothermal properties and biocompatibility. Hydroxyapatite (HA) contains Ca, Mg and P elements, which play important roles in promoting osteogenic differentiation of mesenchymal stem cells (MSCs). In this study, a class of composite nanofibers consisting of MXene nanosheets and HA nanoparticles (M-@HA NFs) are developed based on the synergistic effect of photothermal performance and osteogenic properties. The obtained composite nanofibers demonstrated excellent photothermal properties, and the temperature reached 44 °C under NIR exposure (808 nm). In addition, the composite nanofibers also displayed good biocompatibility and promote the growth and osteogenic differentiation of bone mesenchymal stem cells (BMSCs). More importantly, under NIR exposure, BMSCs on the composite nanofibers achieved much better osteogenic differentiation than those without NIR exposure due to the accelerated release of Ca, Mg and P elements. Therefore, we considered the unique photothermal and osteogenic differentiation to indicate that this new class of MXene composite nanofibers has tremendous application potential in bone tissue engineering.


Assuntos
Nanofibras , Nanopartículas , Diferenciação Celular , Células Cultivadas , Durapatita , Osteogênese , Engenharia Tecidual , Tecidos Suporte
18.
Mater Sci Eng C Mater Biol Appl ; 130: 112421, 2021 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-34702508

RESUMO

Cartilage injuries remain challenging since the regenerative capacity of cartilage is extremely low. The aim was to design a novel type of bioactive glass (BG) scaffold with suitable topology that allows the formation of cartilage-specific extracellular matrix (ECM) after colonization with chondrogenic cells for cartilage repair. Highly porous scaffolds with interconnecting pores consisting of 100 % BG were manufactured using a melting, milling, sintering and leaching technique. Scaffolds were colonized with porcine articular chondrocytes (pAC) and undifferentiated human mesenchymal stromal cells (hMSC) for up to 35 days. Scaffolds displayed high cytocompatibility with no major pH shift. Scanning electron microscopy revealed the intimate pAC-scaffold interaction with typical cell morphology. After 14 days MSCs formed cell clusters but still expressed cartilage markers. Both cell types showed aggrecan, SOX9 gene and protein expression, cartilage proteoglycan and sulfated glycosaminoglycan synthesis for the whole culture time. Despite type II collagen gene expression could not anymore be detected at day 35, protein synthesis was visualized for both cell types during the whole culturing period, increasing in pAC and declining after day 14 in hMSC cultures. The novel BG scaffold was stable, cytocompatible and cartilage-specific protein synthesis indicated maintenance of pAC's differentiated phenotype and chondro-instructive effects on hMSCs.


Assuntos
Cartilagem Articular , Engenharia Tecidual , Animais , Cartilagem , Células Cultivadas , Condrócitos , Condrogênese , Humanos , Porosidade , Suínos , Tecidos Suporte
19.
Mater Sci Eng C Mater Biol Appl ; 130: 112427, 2021 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-34702512

RESUMO

Controlling the architecture of engineered scaffolds is of outmost importance to induce a targeted cell response and ultimately achieve successful tissue regeneration upon implantation. Robust, reliable and reproducible methods to control scaffold properties at different levels are timely and highly important. However, the multiscale architectural properties of electrospun membranes are very complex, in particular the role of fiber-to-fiber interactions on mechanical properties, and their effect on cell response remain largely unexplored. The work reported here reveals that the macroscopic membrane stiffness, observed by stress-strain curves, cannot be predicted solely based on the Young's moduli of the constituting fibers but is rather influenced by interactions on the microscale, namely the number of fiber-to-fiber bonds. To specifically control the formation of these bonds, solvent systems of the electrospinning solution were fine-tuned, affecting the membrane properties at every length-scale investigated. In contrast to dichloromethane that is characterized by a high vapor pressure, the use of trifluoroacetic acid, a solvent with a lower vapor pressure, favors the generation of fiber-to-fiber bonds. This ultimately led to an overall increased Young's modulus and yield stress of the membrane despite a lower stiffness of the constituting fibers. With respect to tissue engineering applications, an experimental setup was developed to investigate the effect of architectural parameters on the ability of cells to infiltrate and migrate within the scaffold. The results reveal that differences in fiber-to-fiber bonds significantly affect the infiltration of normal human dermal fibroblasts into the membranes. Membranes of loose fibers with low numbers of fiber-to-fiber bonds, as obtained from spinning solutions using dichloromethane, promote cellular infiltration and are thus promising candidates for the formation of a 3D tissue.


Assuntos
Nanofibras , Tecidos Suporte , Módulo de Elasticidade , Humanos , Membranas , Engenharia Tecidual
20.
Mater Sci Eng C Mater Biol Appl ; 130: 112434, 2021 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-34702519

RESUMO

Bone defects arising from injury and/or disease are a common and debilitating clinical lesion. While the development of tissue microenvironments utilizing biomimetic constructs is an emerging approach for bone tissue engineering. In this context, bioactive glass nanoparticles (BGNPs) were embedded within polycaprolactone (PCL) scaffolds. The scaffolds exhibit an engineered unidirectional pore structure which are surface activated via oxygen plasma to allow immobilization of simvastatin (SIM) on the pore surface. Microscopic observation indicated the surface modification did not disturb the lamellar orientation of the pores improving the biomimetic formation of hydroxyapatite. Mathematically modelled release profiles reveal that the oxygen plasma pre-treatment can be utilized to modulate the release profile of SIM from the scaffolds. With the release mechanism controlled by the balance between the diffusion and erosion mechanisms. Computational modelling shows that Human Serum Albumin and Human α2-macroglobulin can be utilized to increase SIM bioavailability for cells via a molecular docking mechanism. Cellular studies show positive MG-63 cell attachment and viability on optimized scaffolds with alkaline phosphatase activity enhanced along with enhanced expression of osteocalcoin biomarker.


Assuntos
Preparações Farmacêuticas , Engenharia Tecidual , Biomimética , Humanos , Simulação de Acoplamento Molecular , Osteogênese , Poliésteres , Tecidos Suporte
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