Osteoinductive biomaterial geometries for bone regenerative engineering.
2013
Worldwide, more than 2.2 million patients undergo bone graft procedures annually. In each of these procedures an interface is
formed between the host tissue and the graft material. Synthetic implants exhibit an interface with the host tissue and the formation of a
homogenous interface consisting of bone and void of intervening soft tissue is desired (osseointegration); recent developments have highlighted
the benefit of incorporating nanostructures at that interface. Autograft and allograft bone are frequently used for bone loss, nonunion
fractures, and spinal fusions; however, both are plagued with complications either due to supply or inadequate graft properties. In
contrast to bone tissue engineering, which uses a top-down approach to repair bone defects, bone regenerative engineering uses a bottomup
approach focused on strategies incorporating stem cells, biomaterials, and growth factors alone or in combination to generate or regenerate
bone tissue. Early constructs developed for bone regenerative engineering utilized polymeric microstructures, presenting surface
features with characteristic dimensions similar to that of a cell (1µm – 1000µm). These microstructures were typically biodegradable and
demonstrated an excellent ability to match the mechanics of native bone tissue. They were also osteoconductive—capable of promoting
osteoblast growth. On the other hand, the osteoinductive abilities of these microstructures were lacking. Osteoinduction, or the ability to
promote the progression of a preosteoblastic cell to a mature osteoblast, historically was achieved in two ways: via the addition of
nanoscale ceramics to the microstructures or via an external stimulus such as the addition of bone morphogenetic proteins (BMPs). More
recent developments in bone regenerative engineering have utilized polymeric nanostructures (less than 1µm) with characteristic dimensions
an order of magnitude or more less than that of a cell to stimulate and drive an osteoinductive response in the absence of growth
factors. Despite strong literature evidence supporting the nanostructures’ ability to be both osteoconductive and osteoinductive, there is
still disparity regarding how nanostructures regulate the progression towards an osteoblastic phenotype. This review will explore unique
micro- and nano-architectures, how they initiate osteoinductive signals through pathways similar to BMPs, and how these unique geometries
can be translated to the clinic.
Keywords:
- Correction
- Source
- Cite
- Save
- Machine Reading By IdeaReader
80
References
33
Citations
NaN
KQI