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In the present work, a new combination of synthetic and natural biomaterials is proposed for bone tissue engineering (BTE) applications. In order to mimic the inorganic and organic phases of bone extracellular matrix (ECM), a bioactive glass-ceramic deriving from a SiO2–P2O5–CaO–MgO–Na2O–K2O parent glass, acting as a substrate in form of a slice, was surface-functionalised with a type I collagen-based coating. In particular, the collagen was blended with a water soluble polyurethane (PUR), synthesised from poly(ethylene glycol), 1,6-hexamethylene diisocyanate and N-BOC-serinol. The PUR was designed to expose amino groups on the polymeric chain, which can be exploited for the blend stabilisation through crosslinking. The newly synthesised PUR demonstrated to be non-cytotoxic, as assessed by a biological test with MG-63 osteoblast-like cells. The collagen/PUR blend showed good biocompatibility as well. The polymeric coating on the glass-ceramic samples was produced by surface-silanisation, followed by further chemical grafting of the blend, using genipin as a crosslinker. The glass-ceramic surface was characterised at each functionalisation step, demonstrating that the procedure allowed obtaining a covalent link between the blend and the substrate. Finally, biological tests performed using human periosteal derived precursor cells demonstrated that the proposed polymer-coated material was a good substrate for bone cell adhesion and growth, and a good candidate to mimic the composite nature of the bone ECM.

The influence of using bioactive glass as a sintering aid in the production of tricalcium phosphate (TCP) scaffolds was investigated. The scaffolds were fabricated by sponge replication followed by sintering in a range of temperatures from 1150 to 1300 °C. Morphological investigations by SEM and micro-computed tomography showed that the scaffolds exhibited a three-dimensional trabecular architecture mimicking that of cancellous bone, with high porosity (about 80 vol%) and highly-interconnected macropores with mean pore size of 314 μm. Apart from playing a role in improving the mechanical properties of the scaffolds, glass was shown to enhance the stability of β-TCP by increasing the β → α phase transition temperature.

The development of suitable strategies to treat ageing-related pathologies has attracted the interest of researchers in view of the increasing life expectancy in the next decades. Osteoporosis is a worldwide disease with high prevalence in humans older than 50 that dramatically increases the risk of bone fractures with associated disabilities. The innovative use of new biomaterials as models of the healthy and osteoporotic bone matrix would be a new strategy to study the physiological conditions associated with osteoporosis and the connection between microenvironment changes and the bone ageing process. In this work, experimental bioactive glass substrates were coated with various polymer formulations in order to impart tunable surface features to the whole systems, which will act as models of the healthy and aged bone tissue once they have been colonized by cells.

Bioceramics are clinically used as implantable materials to alleviate pain and restore function to diseased or damaged hard tissues in the body. Bone is especially vulnerable to deterioration and fracture in elderly people because of a loss of bone mass and strength with age (osteoporosis). The goal of this research work is to design and fabricate 3-D bioceramic scaffolds with different pore/strut features that can mimic the architecture of both healthy and osteoporotic bone. The scaffolds were fabricated by sponge replica method using a SiO2–P2O5–CaO–MgO–Na2O–K2O bioactive glass (CEL2) as starting material. Key processing parameters were systematically varied and their influence on the architectural and mechanical features of the scaffolds was assessed. Porosity-strength relationship was studied and modelled by using the theory of cellular solid mechanics. These glass-ceramic scaffolds open new perspectives for bone regenerative approaches and could act as model substrates for a more accurate investigation of bone pathologies.

The purpose of this study was to measure chondrocytes detachment from cellularized constructs cultured in a perfusion bioreactor, and to evaluate the effect of different scaffold coatings on cell adhesion under a fixed flow rate. The scaffolds were polyurethane foams, treated to promote cell attachment and seeded with human chondrocytes. In a preliminary static culture experiment, the scaffolds were imbibed with fetal bovine serum (FBS) and then cultured for 4 weeks. To quantify cell detachment, the number of detached cells from the scaffold treated with FBS was estimated under different interstitial perfusion flow rates and shear stress levels (0.005 mL/min equivalent to 0.05 mPa, 0.023 mL/min equivalent to 0.23 mPa, and 0.045 mL/min equivalent to 0.45 mPa). Finally, groups of scaffolds differently treated (FBS, plasma plus FBS, plasma plus collagen type I) were cultured under a fixed perfusion rate of 0.009 mL/min, equivalent to a shear stress of 0.09 mPa, and the detached cells were counted. Static cultivation showed that cell proliferation increased with time and matrix biosynthesis decreased after the first week of culture. Perfused culture showed that the number of detached cells increased with the perfusion rate on FBS-treated constructs. The plasma-treated/collagen-coated scaffolds showed the highest resistance to cell detachment. To minimize cell detachment, the perfusion rate must be maintained in the order of 0.02 mL/min, giving a shear stress of 0.2 mPa. Our set-up allowed estimating the resistance to cell detachment under interstitial perfusion in a repeatable manner, to test other scaffold coatings and cell types.