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1.
Int J Bioprint ; 7(3): 367, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34286152

RESUMO

Three-dimensional (3D) bioprinting has become a promising strategy for bone manufacturing, with excellent control over geometry and microarchitectures of the scaffolds. The bioprinting ink for bone and cartilage engineering has thus become the key to developing 3D constructs for bone and cartilage defect repair. Maintaining the balance of cellular viability, drugs or cytokines' function, and mechanical integrity is critical for constructing 3D bone and/or cartilage scaffolds. Photo-crosslinkable hydrogel is one of the most promising materials in tissue engineering; it can respond to light and induce structural or morphological transition. The biocompatibility, easy fabrication, as well as controllable mechanical and degradation properties of photo-crosslinkable hydrogel can meet various requirements of the bone and cartilage scaffolds, which enable it to serve as an effective bio-ink for 3D bioprinting. Here, in this review, we first introduce commonly used photo-crosslinkable hydrogel materials and additives (such as nanomaterials, functional cells, and drugs/cytokine), and then discuss the applications of the 3D bioprinted photo-crosslinkable hydrogel scaffolds for bone and cartilage engineering. Finally, we conclude the review with future perspectives about the development of 3D bioprinting photo-crosslinkable hydrogels in bone and cartilage engineering.

2.
Appl Biochem Biotechnol ; 193(10): 3139-3150, 2021 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-34085169

RESUMO

We developed an aptamer that was specific for beclomethasone (BEC) via systematic evolution of ligands by exponential enrichment (SELEX). Development was monitored by real-time quantitative PCR (Q-PCR) and the enriched library was sequenced by high-throughput sequencing. Forty-seven aptamer candidates were obtained; of these, BEC-6 showed the highest affinity (Kd = 0.15 ± 0.02 µM) and did not cross-react with other BEC analogs. We also developed a quantum dot-based assay (QDA) for the detection of BEC that was based upon a quantum dot (QD) composite probe. Under optimized reaction conditions, the linear range of this method for BEC was 0.1 to 10 µM with a low detection limit (LOD) of 0.1 µM. Subsequently, the method was used to detect BEC in Traditional Chinese Medicine (TCM) with a mean recovery of 81.72-91.84%. This is the first report to describe the development of an aptamer against BEC; BEC-6 can also be engineered into QDA for the detection of BEC.

3.
ACS Appl Mater Interfaces ; 12(29): 33246-33255, 2020 Jul 22.
Artigo em Inglês | MEDLINE | ID: mdl-32579334

RESUMO

The intrinsic brittleness and poor damage tolerance of ultrahigh-temperature ceramics are the key obstacles to their engineering applications as nonablative thermal protection materials. Biomimetic layered or "brick-and-mortar" hybrid composites composed of alternative strong/weak interfaces exhibit excellent strength and high toughness; however, the commonly used interfacial materials are weak and have poor thermal stability and ablation resistance, which strictly limit their use in high-temperature and oxidative environments. In this work, ZrB2-based "brick-and-mortar" hybrid ceramics were constructed with a hierarchical biomimetic design to improve the fracture resistance and damage tolerance. ZrB2-20vol %SiC ceramics containing 30 vol % reduced graphene oxide nanosheets were used as the weak interface to increase crack growth resistance without destroying the excellent ablation resistance. Finally, the ZrB2-based "brick-and-mortar" composites achieve the synergy of superior damage tolerance and ablation resistance.

4.
Biomed Mater ; 15(6): 065018, 2020 10 03.
Artigo em Inglês | MEDLINE | ID: mdl-32442992

RESUMO

Endothelial cell (EC) dysfunction is an important predictor of and contributor to the pathobiology of cardiovascular diseases. However, most in vitro studies are performed using monolayer cultures of ECs on 2D tissue polystyrene plates (TCPs), which cannot reflect the physiological characteristics of cells in vivo. Here, we used 2D TCPs and a 3D culture model to investigate the effects of dimensionality and cardiovascular risk factors in regulating endothelial dysfunction. Cell morphology, oxidative stress, inflammatory cytokines and endothelial function were investigated in human umbilical vein endothelial cells (HUVECs) cultured in 2D/3D. The differentially expressed genes in 2D/3D-cultured HUVECs were analysed using Enrichr, Cytoscape and STRING services. Finally, we validated the proteins of interest and confirmed their relevance to TNF-α and the culture microenvironment. Compared with 2D TCPs, 3D culture increased TNF-α-stimulated oxidative stress and the inflammatory response and changed the mediators secreted by ECs. In addition, the functional characteristics, important pathways and key proteins were determined by bioinformatics analysis. Furthermore, we found that some key proteins, notably ACE, CD40, Sirt1 and Sirt6, represent a critical link between endothelial dysfunction and dimensionality, and these proteins were screened by bioinformatics analysis and verified by western blotting. Our observations provide insight into the interdependence between endothelial dysfunction and the complex microenvironment, which enhances our understanding of endothelial biology or provides a therapeutic strategy for cardiovascular-related diseases.


Assuntos
Técnicas de Cultura de Células , Células Endoteliais/citologia , Fator de Necrose Tumoral alfa/química , Doenças Cardiovasculares/metabolismo , Doenças Cardiovasculares/terapia , Sobrevivência Celular/efeitos dos fármacos , Técnicas de Cocultura , Biologia Computacional , Citocinas/metabolismo , Endotélio Vascular/citologia , Células Endoteliais da Veia Umbilical Humana , Humanos , Inflamação , Mediadores da Inflamação/metabolismo , Estresse Oxidativo
5.
Cell Biol Int ; 44(2): 593-602, 2020 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-31670413

RESUMO

Derlin-1 is involved in the elimination of misfolded proteins and has been implicated in the progression of human cancers. However, its prognostic value and biological function in breast cancer remain unknown. Here, we show that Derlin-1 is overexpressed in breast cancer and exhibits oncogenic activities via interaction with UBE2C. Increased expression of Derlin-1 is correlated with lymph node metastasis, advanced clinical stage, and unfavorable overall survival in two cohorts containing over 1,000 patients. Multivariate analyses by the Cox regression model suggest Derlin-1 is an independent factor for poor prognosis. In vitro experiments demonstrate that Derlin-1 expression is transcriptionally upregulated by c-Myc. Ectopic expression of Derlin-1 promotes breast cancer cell proliferation and migration, whereas the knockdown of Derlin-1 results in the opposite phenotypes. Mechanistically, Derlin-1 directly binds to UBE2C to increase the phosphorylation of AKT and ERK. The treatment of UBE2C siRNA markedly attenuates Derlin-1-mediated cell growth and migration. Collectively, our data suggest Derlin-1 is a potential prognostic factor and functions as an oncogene in breast cancer.


Assuntos
Biomarcadores Tumorais/metabolismo , Neoplasias da Mama/patologia , Proliferação de Células , Regulação Neoplásica da Expressão Gênica , Proteínas de Membrana/metabolismo , Enzimas de Conjugação de Ubiquitina/metabolismo , Apoptose , Biomarcadores Tumorais/genética , Neoplasias da Mama/genética , Neoplasias da Mama/metabolismo , Movimento Celular , Feminino , Humanos , Proteínas de Membrana/genética , Fosforilação , Prognóstico , Transdução de Sinais , Células Tumorais Cultivadas , Enzimas de Conjugação de Ubiquitina/genética
6.
J Mech Behav Biomed Mater ; 103: 103532, 2020 03.
Artigo em Inglês | MEDLINE | ID: mdl-31756563

RESUMO

Bioactive glass ceramics have excellent biocompatibility and osteoconductivity; and can form direct chemical bonds with human bones; thus, these ceramic are considered as "Smart" materials. In this study, we develop a new type of bioactive glass ceramic (AP40mod) as a scaffold containing Endothelial progenitor cells (EPCs) and Mesenchymal stem cells (BMSCs) to repair critical-sized bone defects in rabbit mandibles. For in vitro experiments: AP40mod was prepared by Dgital light processing (DLP) system and the optimal ratio of EPCs/BMSCs was screened by analyzing cell proliferation and ALP activity, as well as the influence of genes related to osteogenesis and angiogenesis by direct inoculation into scaffolds. The scaffold showed suitable mechanical properties, with a Bending strength 52.7 MPa and a good biological activity. Additionally, when EPCs/BMSCs ratio were combined at a ratio of 2:1 with AP40mod, the ALP activity, osteogenesis and angiogenesis were significantly increased. For in vivo experiments: application of AP40mod/EPCs/BMSCs (after 7 days of in vitro spin culture) to repair and reconstruct critical-sized mandible defect in rabbit showed that all scaffolds were successfully accurately implanted into the defect area. As revealed by macroscopically and CT at the end of 9 months, defects in the AP40mod/EPCs/BMSCs group were nearly completely covered by normal bone and the degradation rate was 29.9% compared to 20.1% in the AP40mod group by the 3D reconstruction. As revealed by HE and Masson staining analyses, newly formed blood vessels, bone marrow and collagen maturity were significantly increased in the AP40mod/EPCs/BMSCs group compared to those in the AP40mod group. We directly inoculated cells on the novel material to screen for the best inoculation ratio. It is concluded that the AP40mod combination of EPCs/BMSCs is a promising approach for repairing and reconstructing large load bearing bone defect.


Assuntos
Células Progenitoras Endoteliais , Engenharia Tecidual , Animais , Cerâmica , Mandíbula , Osteogênese , Coelhos , Tecidos Suporte
7.
Biomed Eng Online ; 18(1): 87, 2019 Aug 07.
Artigo em Inglês | MEDLINE | ID: mdl-31391047

RESUMO

BACKGROUND: Carotid artery geometry is important for recapitulating a pathophysiological microenvironment to study wall shear stress (WSS)-induced endothelial dysfunction in atherosclerosis. Endothelial cells (ECs) cultured with hydrogel have been shown to exhibit in vivo-like behaviours. However, to date, studies using hydrogel culture have not fully recapitulated the 3D geometry and blood flow patterns of real-life healthy or diseased carotid arteries. In this study, we developed a gelatin-patterned, endothelialized carotid artery model to study the endothelium response to WSS. RESULTS: Two representative regions were selected based on the computational fluid dynamics on the TF-shaped carotid artery: Region ECA (external carotid artery) and Region CS (carotid sinus). Progressive elongation and alignment of the ECs in the flow direction were observed in Region ECA after 8, 16 and 24 h. However, the F-actin cytoskeleton remained disorganized in Region CS after 24 h. Further investigation revealed that expression of vascular cell adhesion molecule-1 (VCAM-1) and intercellular adhesion molecule-1 (ICAM-1) was greatly increased in Region CS relative to that in Region ECA. The physiological WSS in the carotid artery system was found to stimulate nitric oxide (NO) and prostacyclin (PGI2) release and inhibit endothelin-1 (ET-1) release after 24-h perfusion experiments. The effective permeability (E.P) of fluorescein isothiocyanate (FITC)-dextran 40 kDa in Regions ECA and CS was monitored, and it was found that the turbulence WSS value (in Region CS) was less than 0.4 Pa, and there was a significant increase in the E.P relative to that in Region ECA, in which laminar WSS value was 1.56 Pa. The tight junction protein (ZO-1) production was shown that the low WSS in Region CS induced ZO-1-level downregulation compared with that in Region ECA. CONCLUSIONS: The results suggested that the gelatin-based perfusable, endothelial carotid artery model can be effective for studying the pathogenesis of atherosclerosis by which flow dynamics control the endothelium layer function in vitro.


Assuntos
Aterosclerose/patologia , Biomimética/instrumentação , Artérias Carótidas/patologia , Células Endoteliais/patologia , Gelatina , Actinas/metabolismo , Aterosclerose/fisiopatologia , Artérias Carótidas/fisiopatologia , Citoesqueleto/metabolismo , Células Endoteliais/metabolismo , Análise de Elementos Finitos , Hemodinâmica , Hidrodinâmica , Permeabilidade
8.
Oncol Lett ; 18(3): 3072-3080, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31452784

RESUMO

Malignant peripheral nerve sheath tumors (MPNSTs) are unusual and aggressive malignant soft-tissue tumors that comprise 5-10% of all soft-tissue sarcomas. Approximately 50% of MPNST cases are associated with neurofibromatosis type-1 (NF-1). As a rare MPNST subset, the epithelioid variant of MPNST (eMPNST) is histologically characterized by the predominant presence of epithelioid tumor cells, and accounts for <5% of all MPNSTs. In addition, eMPNST is rarely associated with NF-1 when compared with conventional MPNST. Although extensive clinicopathological studies have been conducted on eMPNST, clinicians face difficulty when attempting to make an accurate diagnosis. Subsequently, the biological consequences, including recurrence, metastasis and mortality rate in patients with eMPNST remain unclear. The current study presents the case of a 71-year-old woman with eMPNST and a family history of NF-1 in whom tumors had recurred twice on the lower back. A literature search for eMPNSTs was conducted by browsing PubMed and MEDLINE for English-language articles, as well as references from review articles, and revealed 129 published cases. Only 5 cases of eMPNST were associated with NF-1. The studies were retrospectively reviewed and the clinicopathological data of the patients, including tumor site, treatment, follow-up, prognosis, and immunohistochemical positivity were collected.

9.
Phys Rev Lett ; 122(25): 253201, 2019 Jun 28.
Artigo em Inglês | MEDLINE | ID: mdl-31347860

RESUMO

Stimulated Raman adiabatic passage (stirap) allows efficiently transferring the populations between two discrete quantum states and has been used to prepare molecules in their rovibrational ground state. In realistic molecules, a well-resolved intermediate state is usually selected to implement the resonant stirap. Because of the complex molecular level structures, the detuned stirap always coexists with the resonant stirap and may cause unexpected interference phenomenon. However, it is generally accepted that the detuned stirap can be neglected if compared with the resonant stirap. Here we report on the first observation of interference between the resonant and detuned stirap in the adiabatic creation of ^{23}Na^{40}K ground-state molecules. The interference is identified by observing that the number of Feshbach molecules after a round-trip stirap oscillates as a function of the hold time, with a visibility of about 90%. This occurs even if the intermediate excited states are well resolved, and the single-photon detuning of the detuned stirap is about 1 order of magnitude larger than the linewidth of the excited state and the Rabi frequencies of the stirap lasers. Moreover, the observed interference indicates that if more than one hyperfine level of the ground state is populated, the stirap prepares a coherent superposition state among them, but not an incoherent mixed state. Further, the purity of the hyperfine levels of the created ground state can be quantitatively determined by the visibility of the oscillation.

10.
J Pediatr Surg ; 54(10): 2166-2171, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-30929946

RESUMO

BACKGROUND: Magnetic compression anastomosis (MCA) is a commonly used anastomosis method. MCA was widely used in tissues repair, gastroenterostomy, choledochoenterostomy, and so on. It is safer and more effective than stapler and manual surgical suturing. However, there are few detailed studies on the biomechanical characteristics and tissue transformation mechanisms of the anastomosis process. In this research, taking intestinal tissue as research object, we need to determine an optimal compressive force range to provide a biomechanical reference for the design of anastomats. METHODS: Magnets with different magnetic force groups (2.06, 3.21, 6.27, 13.3 and 19.2 N) were implanted into each dog to form intestinal tissue side-to-side anastomoses. Five dogs were euthanized on each of postoperative day 1, day 3, and day 7. Anastomoses were then harvested and compared with respect to postoperative complications, histology and tear-resistance load capacity (TRLC). RESULTS: The TRLC of anastomotic tissue formed by magnets with different magnetic forces differed markedly, but with the tissue growth, the TRLC differences between groups were decreased. Histology of anastomotic tissue showed that, in the initial stage, the anastomoses compressed by 2.06-N magnets did not form effectively, while the leakage appeared in the anastomoses compressed by 19.2-N magnets, in the rest groups, with magnetic force increasing, severity of ischemia and necrosis of compressed tissue increased and healing speed of anastomotic tissue improved. In the late stage, the influence of magnetic force for anastomotic tissue was gradually diminished. CONCLUSIONS: The magnetic force applied on the magnetic compression anastomats affects the necrosis speed of compressed tissue and the healing speed of anastomotic tissue. The optimal compressive force range for intestinal compression anastomosis is 6.27 N to 13.3 N, and the actual optimal compression pressure is 79.8 kPa - 169 kPa. LEVEL OF EVIDENCE: Magnetic compression anastomosis (MCA) is a commonly used anastomosis method. MCA was widely used in tissues repair, gastroenterostomy, choledochoenterostomy, and so on. It is safer and more effective than stapler and manual surgical suturing. However, there are few detailed studies on the biomechanical characteristics and tissue transformation mechanisms of the anastomosis process. In this research, taking intestinal tissue as research object, we need to determine an optimal compressive force range to provide a biomechanical reference for the design of anastomats.


Assuntos
Anastomose Cirúrgica/métodos , Procedimentos Cirúrgicos do Sistema Digestório/métodos , Intestinos/cirurgia , Terapia de Campo Magnético/métodos , Anastomose Cirúrgica/instrumentação , Animais , Força Compressiva , Procedimentos Cirúrgicos do Sistema Digestório/instrumentação , Cães , Intestinos/patologia , Intestinos/fisiologia , Terapia de Campo Magnético/efeitos adversos , Campos Magnéticos , Fenômenos Magnéticos , Imãs , Complicações Pós-Operatórias , Pressão , Cicatrização
11.
J Surg Res ; 239: 52-59, 2019 07.
Artigo em Inglês | MEDLINE | ID: mdl-30802705

RESUMO

BACKGROUND: After magnetic compressive anastomosis, anastomat passage through the narrow channels of the digestive tract is difficult owing to the device's large volume. Such passage can lead to mechanical damage to the digestive tract or anastomat's unstable excretion time. This article presents a new magnetic compressive anastomotic approach. METHODS: A magnetic elliptical-ring compressive anastomat was designed and evaluated for placement and passage in vitro. Nine young adult dogs underwent laparotomy with intestinal tissue side-to-side anastomosis. Four different groups of magnetic compressive anastomats of two different magnetic force levels (20 N or 30 N) and shapes (round or elliptical) were implanted into each dog simultaneously. Three dogs were euthanized on each of postoperative day 1, day 4, and day 7. Anastomoses were then compared with respect to histology and tensile fracture force. RESULTS: The magnetic elliptical-ring compressive anastomat was functional but produced less obstruction compared to its round counterpart during passage through the esophagus and intestine. Nine dogs underwent successful surgery and harvesting of 30 total anastomoses. Histology of anastomotic tissue showed that, along the newly formed tunnel connecting the two sides of anastomotic tissues, compressed tissues became thinner and fell off, and initial anastomoses formed on the seventh postoperative day. There were large differences in tensile fracture force among the anastomoses formed by magnets with different magnetic forces of the same structure. However, the magnetic compressive anastomat structure did not affect anastomotic repair during magnetic compression anastomosis. CONCLUSIONS: The magnetic elliptical-ring compressive anastomat is an efficient anastomotic device that can be used easily and with good passage. The device has good biomechanical properties and can be used with endoscopy to reduce operative time.


Assuntos
Desenho de Equipamento , Intestinos/cirurgia , Imãs , Anastomose Cirúrgica/instrumentação , Anastomose Cirúrgica/métodos , Animais , Fenômenos Biomecânicos , Cães , Estudos de Viabilidade , Técnicas In Vitro , Masculino , Modelos Animais , Período Pós-Operatório , Resistência à Tração
12.
Science ; 363(6424): 261-264, 2019 01 18.
Artigo em Inglês | MEDLINE | ID: mdl-30655438

RESUMO

Resonances in ultracold collisions involving heavy molecules are difficult to simulate theoretically and have proven challenging to detect. Here we report the observation of magnetically tunable Feshbach resonances in ultracold collisions between potassium-40 (40K) atoms and sodium-23-potassium-40 (23Na40K) molecules in the rovibrational ground state. We prepare the atoms and molecules in various hyperfine levels of their ground states and observe the loss of molecules as a function of the magnetic field. The atom-molecule Feshbach resonances are identified by observing an enhancement of the loss. We have observed 11 resonances in the magnetic field range of 43 to 120 gauss. The observed atom-molecule Feshbach resonances at ultralow temperatures probe the three-body potential energy surface with exceptional resolution and will help to improve understanding of ultracold collisions.

13.
Se Pu ; 37(12): 1331-1336, 2019 Dec 08.
Artigo em Chinês | MEDLINE | ID: mdl-34213135

RESUMO

A method based on high-performance liquid chromatography-tandem mass spectrometry was developed for the determination of sodium picosulfate in enzyme products. Sodium picosulfate is a new slimming aid that is illegally added to food products. The existing analytical methods are not suitable for application to jellies and gel candies, thus triggering the need for developing a new method. The samples were extracted with water and passed through a polyamide cartridge. The extracts were separated on a Thermo Accucore RP-MS column (100 mm×2.1 mm, 2.6 µm) using acetonitrile-10 mmol/L ammonium acetate solution (15:85, v/v) as the mobile phase. The flow rate of the mobile phase was 0.3 mL/min, and the column temperature was 35 ℃. Detection was carried out in the multiple reaction monitoring (MRM) mode. Quantification analysis was performed by the external standard method. The results showed that sodium picosulfate had a good linear relationship in the range of 5-500 µg/L, and the correlation coefficient (r) was 0.9999. The limit of detection (LOD) was 0.05 mg/kg. The average recoveries of sodium picosulfate in different matrices were in the range of 89.2%-111.8%, with the relative standard deviations (RSDs) of 2.5%-10.4%. The method was applied to the analysis of 152 samples, and 58 positive samples were detected. The positive rate was 38.2%. The developed method is accurate and sensitive, and it is suitable for detecting sodium picosulfate in enzyme products.

14.
Biomech Model Mechanobiol ; 18(3): 607-616, 2019 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-30570674

RESUMO

Sheep model is the most favourable choice for animal study for functional evaluation of the cervical fusion prostheses before clinical application; however, significantly large differences between sheep and human existed in terms of morphological characteristics and daily-activity motions. Questions should be raised as whether the differences between the two species have influence on the reliability of sheep model. Finite element models (FEM) of the cervical spinal system were built to characterize the differences between the two species with respect to the range of motion (ROM) and biomechanical behaviour, and experimental cadaver tests on both species were employed for validation purposes. Results indicate that sheep model represents the worst-case scenario of the human model with exaggerated stresses (up to 3 times more) and ROM (up to 10 times more). Moreover, sheep model is very sensitive to the variation of prostheses design, whilst human model does not, which denotes that the sheep model provides a rather amplified effect of a certain design for its biomechanical performance. Therefore, caution needs to be taken when sheep models were used as the animal model for functional evaluation over various design, and the FEM built in this study can be employed as an effective methodology for performance evaluation of cage prostheses of cervical spine.


Assuntos
Vértebras Cervicais/cirurgia , Fusão Vertebral , Animais , Fenômenos Biomecânicos , Análise de Elementos Finitos , Humanos , Modelos Animais , Reprodutibilidade dos Testes , Ovinos
15.
Chem Biol Drug Des ; 93(1): 29-37, 2019 01.
Artigo em Inglês | MEDLINE | ID: mdl-30107085

RESUMO

In this study, HPLC-MS/MS with triple-quadrupole tandem mass spectrometer was used to analyze the base-catalyzed thermal degradation derivative of progesterone in Chinese Pharmacopoeia. The full-scan spectrometry revealed that the degradation product was an isomer of progesterone, it was proposed as impurity M ((17α)-pregn-4-ene-3,20-dione) in European Pharmacopoeia, and both the derivative and progesterone were neutral molecules. Four kinds of chromatographic column characterization databases including PQRI database using Snyder/Dolan method, the USP chromatographic column database using the SRM 870 tests, the Tanaka/Euerby approach within the ACD program, and the Hoogmartens approach were compared. Combing the principles of column characterization databases with the system requirement of progesterone-related substances testing, a suitable PQRI-based method was finally set up for progesterone-related substances detecting. Our results indicated that PQRI system of Snyder/Dolan method was the most suitable system for related substances detection of progesterone.


Assuntos
Cromatografia Líquida de Alta Pressão/métodos , Progesterona/análise , Bases de Dados de Compostos Químicos , Espectrometria de Massas em Tandem
16.
Cryobiology ; 82: 1-7, 2018 06.
Artigo em Inglês | MEDLINE | ID: mdl-29752974

RESUMO

To address issues such as transportation and the time-consuming nature of tissue-engineered liver for use as an effective drug metabolism and toxicity testing model, "ready-to-use" cryogenic tissue-engineered liver needs to be studied. The research developed a cryogenic tissue-engineered liver slice (TELS), which comprised of HepG2 cells and calcium alginate gel. Cell viability and liver-specific functions were examined after different cryopreservation and recovery culture times. Then, cryogenic TELSs were used as a drug-testing model and treated with Gefitinib. Cryogenic TELSs were stored at -80 °C to ensure high cell viability. During recovery in culture, the cells in the cryogenic TELS were evenly distributed, massively proliferated, and then formed spheroid-like aggregates from day 1 to day 13. The liver-specific functions in the cryogenic TELS were closely related to cryopreservation time and cell proliferation. As a reproducible drug-testing model, the cryogenic TELS showed an obvious drug reaction after treatment with the Gefitinib. The present study shows that the cryopreservation techniques can be used in drug-testing models.


Assuntos
Alginatos/farmacologia , Antineoplásicos/farmacologia , Criopreservação/métodos , Crioprotetores/farmacologia , Ensaios de Seleção de Medicamentos Antitumorais/métodos , Gefitinibe/farmacologia , Fígado/metabolismo , Engenharia Tecidual/métodos , Proliferação de Células , Sobrevivência Celular , Células Hep G2 , Humanos , Esferoides Celulares/efeitos dos fármacos , Células Tumorais Cultivadas
17.
Sensors (Basel) ; 17(6)2017 Jun 09.
Artigo em Inglês | MEDLINE | ID: mdl-28598386

RESUMO

Generally, many beamforming methods are derived under the assumption of white noise. In practice, the actual underwater ambient noise is complex. As a result, the noise removal capacity of the beamforming method may be deteriorated considerably. Furthermore, in underwater environment with extremely low signal-to-noise ratio (SNR), the performances of the beamforming method may be deteriorated. To tackle these problems, a noise removal method for uniform circular array (UCA) is proposed to remove the received noise and improve the SNR in complex noise environments with low SNR. First, the symmetrical noise sources are defined and the spatial correlation of the symmetrical noise sources is calculated. Then, based on the preceding results, the noise covariance matrix is decomposed into symmetrical and asymmetrical components. Analysis indicates that the symmetrical component only affect the real part of the noise covariance matrix. Consequently, the delay-and-sum (DAS) beamforming is performed by using the imaginary part of the covariance matrix to remove the symmetrical component. However, the noise removal method causes two problems. First, the proposed method produces a false target. Second, the proposed method would seriously suppress the signal when it is located in some directions. To solve the first problem, two methods to reconstruct the signal covariance matrix are presented: based on the estimation of signal variance and based on the constrained optimization algorithm. To solve the second problem, we can design the array configuration and select the suitable working frequency. Theoretical analysis and experimental results are included to demonstrate that the proposed methods are particularly effective in complex noise environments with low SNR. The proposed method can be extended to any array.

18.
Proc Inst Mech Eng H ; 231(6): 525-533, 2017 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-28639517

RESUMO

The aim of this study was to design a hemi-pelvic prosthesis for a patient affected by pelvic sarcoma. To investigate the biomechanical functionality of the pelvis reconstructed with designed custom-made prosthesis, a patient-specific finite element model of whole pelvis with primary ligaments inclusive was constructed based on the computed tomography images of the patient. Then, a finite element analysis was performed to calculate and compare the stress distribution between the normal and implanted pelvis models when undergoing three different static conditions-both-leg standing, single-leg standing for the healthy and the affected one. No significant differences were observed in the stresses between the normal and reconstructed pelvis for both-leg standing, but 20%-40% larger stresses were predicted for the peak stress of the single-leg standing (affected side). Moreover, two- to threefold of peak stresses were predicted within the prostheses compared to that of the normal pelvis especially for single-leg standing case, however, still below the allowable fatigue limitation. The study on the load transmission functionality of prosthesis indicated that it is crucial to carry out finite element analysis for functional evaluation of the designed customized prostheses before three-dimensional printing manufacturing, allowing better understanding of the possible peak stresses within the bone as well as the implants for safety precaution. The finite element model can be equally applicable to other bone tumor model for biomechanical studying.


Assuntos
Neoplasias Ósseas/terapia , Análise de Elementos Finitos , Ossos Pélvicos , Desenho de Prótese/métodos , Fenômenos Biomecânicos , Neoplasias Ósseas/diagnóstico por imagem , Neoplasias Ósseas/fisiopatologia , Humanos , Ossos Pélvicos/diagnóstico por imagem , Ossos Pélvicos/fisiopatologia , Impressão Tridimensional , Tomografia Computadorizada por Raios X
19.
J Mater Chem B ; 5(43): 8579-8590, 2017 Nov 21.
Artigo em Inglês | MEDLINE | ID: mdl-32264526

RESUMO

Most of the existing tissue-engineered scaffolds for the regeneration of anterior cruciate ligament (ACL) are unable to recapitulate the structural/compositional/mechanical gradients at native ACL-bone interface. Herein, we present a unique electrospinning strategy to fabricate microfiber-reinforced nanofibrous scaffolds with structure and composition gradients. The orientations of the electrospun nanofibers gradually change from random to highly aligned, and the contents of nano-hydroxyapatite (nHA) and bone morphogenesis protein (BMP-2) encapsulated into the nanofibers exhibit gradient variation. The gradient nanofibrous scaffolds were found to regulate cellular morphology and zonal bone-specific differentiation in vitro. The incorporation of microfibers significantly improved the mechanical property of the gradient nanofibrous scaffolds, which was similar to native ACL-bone fixation after implantation in vivo. Histological observations revealed that the gradient scaffolds facilitated the formation of fibrocartilage transitional zone at graft and bone attachments that are similar to native ligament-to-bone interface. We envision that the presented method might provide biomimetic physical/chemical/mechanical microenvironments for enhanced multitissue regeneration particularly at the soft-hard tissue interface.

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