Biomedical Engineering Reference
In-Depth Information
13
Mesopore Bioglass/Silk Composite Scaffolds
for Bone Tissue Engineering
Chengtie Wu and Yin Xiao
Queensland University of Technology
Australia
1. Introduction
In the past 20 years, mesoporous materials have been attracted great attention due to their
significant feature of large surface area, ordered mesoporous structure, tunable pore size
and volume, and well-defined surface property. They have many potential applications,
such as catalysis, adsorption/separation, biomedicine, etc. [1]. Recently, the studies of the
applications of mesoporous materials have been expanded into the field of biomaterials
science. A new class of bioactive glass, referred to as mesoporous bioactive glass (MBG),
was first developed in 2004. This material has a highly ordered mesopore channel structure
with a pore size ranging from 5-20 nm [1]. Compared to non-mesopore bioactive glass (BG),
MBG possesses a more optimal surface area, pore volume and improved
in vitro
apatite
mineralization in simulated body fluids [1,2]. Vallet-Regí et al. has systematically
investigated the in vitro apatite formation of different types of mesoporous materials, and
they demonstrated that an apatite-like layer can be formed on the surfaces of Mobil
Composition of Matters (MCM)-48, hexagonal mesoporous silica (SBA-15), phosphorous-
doped MCM-41, bioglass-containing MCM-41 and ordered mesoporous MBG, allowing
their use in biomedical enineering for tissue regeneration [2-4]. Chang et al. has found that
MBG particles can be used for a bioactive drug-delivery system [5,6]. Our study has shown
that MBG powders, when incorporated into a poly (lactide-co-glycolide) (PLGA) film,
significantly enhance the apatite-mineralization ability and cell response of PLGA films.
compared to BG [7]. These studies suggest that MBG is a very promising bioactive material
with respect to bone regeneration. It is known that for bone defect repair, tissue engineering
represents an optional method by creating three-dimensional (3D) porous scaffolds which
will have more advantages than powders or granules as 3D scaffolds will provide an
interconnected macroporous network to allow cell migration, nutrient delivery, bone
ingrowth, and eventually vascularization [8]. For this reason, we try to apply MBG for bone
tissue engineering by developing MBG scaffolds. However, one of the main disadvantages
of MBG scaffolds is their low mechanical strength and high brittleness; the other issue is that
they have very quick degradation, which leads to an unstable surface for bone cell growth
limiting their applications.
Silk fibroin, as a new family of native biomaterials, has been widely studied for bone and
cartilage repair applications in the form of pure silk or its composite scaffolds [9-14].
Compared to traditional synthetic polymer materials, such as PLGA and poly(3-
