1,720,992 research outputs found
Automation and control of bioreactor-based cell culture: medium exchange driven by on‐line pH monitoring.
No full textWHOLE PROCESS TO BLOOD VESSEL TISSUE ENGINEERING: DEVELOPMENT OF A NEW MULTIFUNCTIONAL DEVICE
No full textECM from decellularised tissues as an additive for polysaccharidic hybrid gels
No full textThe use of decellularised tissues represents a valid and emerging alternative over traditional synthetic scaffolds, which have limited ability to mimic the sophisticated tissue specificity1. Within the tissue engineering context, gels composed by decellularised tissues have been produced through enzymatic digestion followed by basic pH treatment2. Nevertheless, low viscosity, stability and reproducibility often limit their applicative potential. Herein, ECM, obtained from porcine blood vessels, was imbedded within alginate gels and compared to both alginate and alginate/gelatin gels aiming to process decellularised tissues in diverse physical forms and therefore broaden their application. Porcine blood vessels were decellularised1 and gels were further obtained adapting the procedure previously described2. Gels containing ECM or gelatin (8 mg/ml) and different concentrations of alginate (2-20 mg/ml) were produced by internal gelation (CaCO3 2,8% w/v, D- (+)-gluconic acid δ-lactone 0,5% w/v). The alginate samples were obtained preserving the final polymer concentration (10,13,18, 28 mg/ml). Rheological characterization was performed by time, frequency and temperature sweep analyses3. Stability tests were conducted using cell culture medium (complete DMEM medium) from 3 hours up to 7 days. Additionally, preliminary biological characterization was assessed through DNA content after seeding EA.hy 926 for 1 day. ECM-loaded alginate gels (AlgECM) samples were successfully obtained for all the concentration tested. All the samples could be removed from a mould while retaining the shape. The storage and loss moduli of all the tested alginate concentrations were frequency-independent, with the storage modulus higher than the loss modulus, therefore exhibiting gel behaviour. Higher final polymer concentration resulted in gels with higher complex viscosity. Overall, AlgECM samples showed higher values of both storage and loss moduli and higher stability in the medium comparing with unloaded alginate gels. Samples obtained with gelatin could not be produced at polymer concentrations lower than 18 mg/ml. The AlgECM samples remained stable in cell culture medium; samples with the lowest concentration of alginate (2 mg/ml of alginate and 8 mg/ml w/v of ECM) degraded after 7 days. A first biological characterization indicated an increased number of cells for AlgECM gels compared to alginate and alginate/gelatin samples. A novel gel composed of alginate and native vascular decellularised ECM is here proposed. AlgECM gels able to combine the properties of its components. Alginate improved ECM gels reproducibility and allowed the tailoring of gels rheological properties through the variation of alginate concentration. The use of ECM should promote the creation of a tissue-specific material, able to enhance cell growth and proliferation. However, a wider biological characterization should be conducted to test the ECM influence. References 1. Cells Tissues Organs 200:363–373, 2015. 2. Biomaterials 29:1630-1637, 2008. 3. Carbohyd. Polym. 103:339–347, 2014
pH-triggered automatic medium exchange: a step forward toward GMP-compliant tissue engineering manufacturing processes;
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Estimation of the physiological mechanical conditioning in vascular tissue engineering by a predictive fluid-structure interaction approach
Full text linkThe in vitro replication of physiological mechanical conditioning through bioreactors plays a crucial role in the development of functional Small-Caliber Tissue-Engineered Blood Vessels. An in silico scaffold-specific model under pulsatile perfusion provided by a bioreactor was implemented using a fluid-structure interaction (FSI) approach for viscoelastic tubular scaffolds (e.g. decellularized swine arteries, DSA). Results of working pressures, circumferential deformations, and wall shear stress on DSA fell within the desired physiological range and indicated the ability of this model to correctly predict the mechanical conditioning acting on the cells-scaffold system. Consequently, the FSI model allowed us to a priori define the stimulation pattern, driving in vitro physiological maturation of scaffolds, especially with viscoelastic properties
A new strategy for the decellularisation of large equine tendons as biocompatible tendon substitutes
Full text linkTendon ruptures and/or large losses remain to be a great clinical challenge and often require full replacement of the damaged tissue. The use of auto- and allografts or engineered scaffolds is an established approach to restore severe tendon injuries. However, these grafts are commonly related to scarce biocompatibility, site morbidity, chronic inflammation and poor biomechanical properties. Recently, the decellularisation techniques of allo- or xenografts using specific detergents have been studied and have been found to generate biocompatible substitutes that resemble the native tissue. This study aims to identify a novel decellularisation protocol for large equine tendons that would produce an extracellular matrix scaffold suitable for the regeneration of injured tendons in humans. Specifically, equine tendons were treated either with tri (n-butyl) phosphate alone, or associated to multiple concentrations of peracetic acid (1, 3 and 5 %), which has never before been tested in vitro.Samples were then analysed by histology and with biochemical, biomechanical, and cytotoxicity tests. The best decellularisation protocol, resulting from these examinations, was selected and the chosen scaffold was re-seeded with murine fibroblasts. Resulting grafts were tested for cell viability, histologic analysis, DNA and collagen content. The results identified 1 % tri (n-butyl) phosphate combined with 3 % peracetic acid as the most suitable decellularised matrix in terms of biochemical and biomechanical properties. Moreover, the non-cytotoxic nature of the decellularised matrix allowed for good fibroblast reseeding, thus demonstrating a biocompatible matrix that will be suitable for tendon tissue engineering and hopefully as substitutes in severe tendon damages
Ingegnerizzazione dle tessuto muscolare : sviluppo di un bioreattore small scale per imaging
No full textLAUREA MAGISTRAL
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