Human adipose derived stem cells are superior to human osteoblasts (HOB) in bone tissue engineering on a collagen-fibroin-ELR blend

The ultrastructure of the bone provides a unique mechanical strength against compressive, torsional andtensional stresses. An elastin-like recombinamer (ELR) with a nucleation sequence for hydroxyapatitewas incorporated into films prepared from a collagen-silk fibroin blend carrying microchannel patternsto stimulate anisotropic osteogenesis. SEM and fluorescence microscopy showed the alignment ofadipose-derived stem cells (ADSCs) and the human osteoblasts (HOBs) on the ridges and in the groovesof microchannel patterned collagen-fibroin-ELR blend films. The Young's modulus and the ultimatetensile strength (UTS) of untreated films were 0.58 ± 0.13 MPa and 0.18 ± 0.05 MPa, respectively. After 28days of cell culture, ADSC seeded film had a Young's modulus of 1.21 ± 0.42 MPa and UTS of0.32 ± 0.15 MPa which were about 3 fold higher than HOB seeded films. The difference in Young'smodulus was statistically significant (p: 0.02). ADSCs attached, proliferated and mineralized better thanthe HOBs. In the light of these results, ADSCs served as a better cell source than HOBs for bone tissueengineering of collagen-fibroin-ELR based constructs used in this study. We have thus shown theenhancement in the tensile mechanical properties of the bone tissue engineered scaffolds by usingADSCs.

Biomolecular functionalization for enhanced cell–material interactions of poly(methyl methacrylate)surfaces 5th China-Europe Symposium on Biomaterials in Regenerative Medicine(CESB 2015)Hangzhou,China April 7–10,2015

The integration of implants or medical devices into the body tissues requires of good cell–material interactions.However,most polymeric materials used for these applications lack on biological cues,which enhanced mid-and long-term implant failure due to weak integration with the surrounding tissue.Commonly used strategies for tissue–material integration focus on functionalization of the material surface by means of natural proteins or short peptides.However,the use of these biomolecules involves major drawbacks such as immunogenic problems and oversimplification of the constructs.Here,designed elastin-like recombinamers(ELRs)are used to enhance poly(methyl methacrylate)surface properties and compared against the use of short peptides.In this study,cell response has been analysed for different functionalization conditions in the presence and absence of a competing protein,which interferes on surface–cell interaction by unspecific adsorption on the interface.The study has shown that ELRs can induce higher rates of cell attachment and stronger cell anchorages than short peptides,being a better choice for surface functionalization.

An elastin-like recombinamer-based bioactive hydrogel embedded with mesenchymal stromal cells as an injectable scaffold for osteochondral repair

The aim of this study was to evaluate injectable,in situ cross-linkable elastin-like recombinamers(ELRs)for osteochondral repair.Both the ELR-based hydrogel alone and the ELR-based hydrogel embedded with rabbit mesenchymal stromal cells(rMSCs)were tested for the regeneration of critical subchondral defects in 10 New Zealand rabbits.Thus,cylindrical osteochondral defects were filled with an aqueous solution of ELRs and the animals sacrificed at 4months for histological and gross evaluation of features of biomaterial performance,including integration,cellular infiltration,surrounding matrix quality and the new matrix in the defects.Although both approaches helped cartilage regeneration,the results suggest that the specific composition of the rMSC-containing hydrogel permitted adequate bone regeneration,whereas the ELR-based hydrogel alone led to an excellent regeneration of hyaline cartilage.In conclusion,the ELR cross-linker solution can be easily delivered and forms a stable well-integrated hydrogel that supports infiltration and de novo matrix synthesis.

Silk-ELR co-recombinamer covered stents obtained by electrospinning

In the field of tissue engineering the choice of materials is of great importance given the possibility to use biocompatible polymers produced by means of biotechnology.A large number of synthetic and natural materials have been used to this purpose and processed into scaffolds using Electrospinning technique.Among materials that could be used for the fabrication of scaffold and degradable membranes,natural polymers such as collagen,elastin or fibroin offer the possibility to design structures strictly similar to the extracellular matrix(ECM).Biotechnology and genetic engineering made possible the advent of a new class of biopolymers called protein-based polymers.One example is represented by the silk-elastin-proteins that combine the elasticity and resilience of elastin with the high tensile strength of silk-fibroin and display engineered bioactive sequences.In this work,we use electrospinning technique to produce a fibrous scaffold made of the corecombinamer Silk-ELR.Obtained fibres have been characterized from the morphological point of view.Homogeneity and morphology have been explored using Scanning Electron Microscopy.A thorough study regarding the influence of Voltage,flow rate and distance have been carried out to determine the appropriate parameters to obtain the fibrous mats without defects and with a good distribution of diameters.Cytocompatibility has also been in vitro tested.For the first time we use the co-recombinamer Silk-ELR for the fabrication of a 2.5 angioplasty balloon coating.This structure could be useful as a coated scaffold for the regeneration of intima layer of vessels.