Extruded Ceramic Microelectrodes for Biomedical Applications

A new process, based on the micro-co-extrusion of preceramic precursors, has been studied for manufacturing ceramic microelectrodes to be used in biomedical applications. Commercially available silicon polymers were applied and proper doping resulted in electrically conductive ceramic filaments. Chemical reticulation and high-temperature pyrolysis were applied to convert the polymeric resins into Si-O-C ceramic materials. Circular microelectrodes were manufactured with diameters between 100 μm and 5 mm with a different number of inner conductive lines (from 1 to 80). The flexural strength of the filaments depended on the outer diameter size; doping with carbon black produced filaments with an average conductivity of approximately 0.4 S/cm for a 50% weight carbon black load. The results achieved by in vitro studies confirmed a good biological performance of Si-O-C ceramic structures with both hard and soft tissue cell models.

Positioning of a contextual implant along with a sinus lift anchored with a block of heterologous bone

During a sinus lift procedure the main requirement in order to position an implant is to have a maxillary sinus floor cortical bone thick enough to guarantee a primary stability in the implant inserted. In this way, the healing process is facilitated and osseointegration of the titanium surface may occur simultaneously, thus reducing the waiting time for the engraftment of the implant into the body. Unfortunately, these conditions are not always present. Hence, the need of developing an alternative approach that could simultaneously allow to perform sinus floor elevation along with an implant placement. Here we present the case of a 62-year-old patient that requires implant-prosthetic rehabilitation from 1.2 to 1.6 at diagnosis. In this study, we reported a novel application derived from the use of a heterologous bone scaffold (SmartBone@) in a sinus lift procedure. We showed the successful implant along with sinus lift with SmartBone@, both at the time of the surgery and after follow-up of the patient at 10 months from the implant. The possibility to perform simultaneously the contextual implant along with sinus lift dramatically reduced the waiting time for the patient of minimum 5-6 months required for osseointegration of the grafted biomaterials, before performing the implant procedure. This surgery represents an advance both in terms of medical technique and as life-benefit for the patient.

RECONSTRUCTION OF THE ZYGOMATIC BONE WITH SMARTBONE®: CASE REPORT

The repair of complex craniofacial bone defects is challenging and a successful result depends on the defect size, the quality of the soft tissue covering the defect and the choice of reconstructive method. Autologous bone grafts are the gold standard for bone replacement. Tissue engineered constructs are temporary substitutes developed to treat damaged or lost tissue. Recent advances in materials science have provided an abundance of innovations, underlining the increasing importance of polymer in this field. The Galeazzi Orthopedical institute of Milan received a Serbian soldier who reported a deep wound, due to the explosion of a grenade, during former-Yugoslavia’s war. His left cheekbone was completely lost, together with the floor of the left eye. SmartBone® technology allowed the realization of custom-made grafts which perfectly fitted the bone defect thanks to mechanical strength, also at small thicknesses, and the ability to be shaped without powder formation or unpredicted fractures. Tissue engineering approaches to regeneration utilize 3-dimensional (3D) biomaterial matrices that interact favorably with cells. The potential benefits of using a tissue engineering approach include reduced donor site morbidity, shortened operative time, decreased technical difficulty of the repair, ability to closely mimic the in vivo microenvironment in an attempt to recapitulate normal craniofacial development: this 36-month case study allowed to prove that SmartBone® custom-made bone grafts are an effective solution, gathering such benefits and being available now for daily routine.

COMPOSITE POLYMER-COATED MINERAL SCAFFOLDS FOR BONE REGENERATION: FROM MATERIAL CHARACTERIZATION TO HUMAN STUDIES

Bovine bone xenografts, made of hydroxyapatite (HA), were coated with poly(L-lactide-co-ε- caprolactone) (PLCL) and RGD-containing collagen fragments in order to increase mechanical properties, hydrophilicity, cell adhesion and osteogenicity. In vitro the scaffold microstructure was investigated with Environmental Scanning Electronic Microscopy (ESEM) analysis and micro tomography, while mechanical properties were investigated by means compression tests. In addition, cell attachment and growth within the three-dimensional scaffold inner structure were validated using human osteosarcoma cell lines (SAOS-2 and MG-63). Standard ISO in vivo biocompatibility studies were carried out on model animals, while bone regenerations in humans were performed to assess the efficacy of the product. All results from in vitro to in vivo investigations are here reported, underlining that this scaffold promotes bone regeneration and has good clinical outcome.

Gene delivery systems for gene therapy in tissue engineering and central nervous system applications

The present review aims to describe the potential applications of gene delivery systems to tissue engineering and central nervous system diseases. Some key experimental work has been done with interesting results, but the subject is far from being fully explored. The combined approach of gene therapy and material science has a huge potential to improve the therapeutic approaches now available for a wide range of medical applications. Focus is given to this multidisciplinary strategy in neurodegenerative pathologies, where the use of polymeric matrices as gene carriers might make a crucial difference.

Porous biodegradable microtubes-based scaffolds for tissue engineering, part I: production and preliminary in vitro evaluation

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PURPOSE

</b></i>we aimed at investigating spinning as a potential technology to produce porous microtubes for constructing scaffolds. Spinning is indeed a well known technique for producing polymeric fibres, also used in the biomedical field, but its applications for tissue engineering purposes has never been deeply investigated. <i><b>

METHOD

</b></i> the behaviour of a multi-phase poly-lactide-caprolactone copolymer based solution was here studied for the production under spinning condition of porous microtubes for patterning planar and three dimensional bioactive systems to be used for tissue regeneration. Obtained non-woven fabrics were tested investigating cells response with fibroblast, osteoblasts and chondrocytes. <i><b>

RESULTS

</b></i>once achieved optimal process parameters, microtubes were produced with a controlled and well diffused porosity which were then used to build two and three dimensional scaffolds. Cytocompatibility tests performed on these scaffolds showed good results on all tested cell models, both qualitatively (SEM imaging) and quantitatively. Particularly, cell proliferation assays by Alamar Blue staining indicated increasing trends with time and comparable values with controls. <i><b>

CONCLUSIONS

</b></i>results hereby described represent a proof of concept of the process developed and its applicability for obtaining microtubes with controlled porosity. Moreover, two and three dimensional scaffolds built from such fibres showed to be very promising substrates for cell adhesion and growth. Finally, the process developed can be taken into GMP qualification and thus scaffolds can be upgraded to medical devices and used for regenerative medicine into human applications.

Engineering injured spinal cord with bone marrow-derived stem cells and hydrogel-based matrices: a glance at the state of the art

Concerning the broad topic of neural tissue engineering, we present a review relating to the state of the art in spinal cord injury repair strategies. Particular attention is given to spinal cord damage causes and effects, in neural and mesenchymal stem cell therapeutic approaches, in the use of hydrogels as cell carriers and in the mathematical modeling of involved phenomena. High importance is given to multidisciplinary strategies applied to spinal cord repair, since new research frontiers are believed to be now on 3D gel/cells and neuroprotective agent constructs for neural reconstruction purposes.