SCAFFOLD CONSIDERATIONS FOR OSTEOCHONDRAL TISSUE ENGINEERING - Intelligent Scaffolds for Tissue Engineering and Regenerative Medicine - page 789

approaches, enabling the researcher to carefully tailor the scaf-
fold properties to the mechanical and physiological needs of
bothtissuetypes.Ofcourseintegrationbetweenthetwomateri-
alsisagainacriticalconcern.Thisapproachhasshownpromise
in vitro , 44 , 45 but there is a need to properly characterize these
treatmentregimesinjointdefectsoflargeanimalstofullyassess
repair potential.
(d) The fourth scaffold approach referred to by Martin et al .was
to use a single homogenous scaffold for both components, as
described by Cao et al . 46 - 48 Once again more research and
better characterization is required to properly assess the best
approach of those described here. To confound that issue, as
also discussed by Martin et al ., these scaffolds have been (i)
loaded with a single cell source having chondrogenic capacity,
(ii) loaded with two cell sources having either chondrogenic or
osteogenic capacities, (iii) loaded with a single cell source hav-
ing both chondrogenic and osteogenic differentiation capacity,
or (iv) used in a cell-free approach.
Within the field of tissue engineering several or all of the above-
mentioned approaches have been attempted, most of them in vitro
thus far. This is one classification system that could be used to
describe the current approaches used, but there are also other con-
siderations/approaches to consider, as willbediscussed shortly.
Commercially, two products on the market which use a multilay-
ered approach that are currently undergoing clinical trials include
Smith&Nephew'sTRUFITproduct,whichisproposedasaone-step
arthroscopic procedure for repairing bone and articular cartilage
defects, and Orthomimetic's Chondromimetic product, which pro-
poses to support the body's natural repair mechanisms to encour-
age the simultaneous repair of both articular cartilage and the bone
to which it is attached. Both of these products are bilayered with
different material and properties in the parts aimed for bone and
cartilage regeneration, respectively. TRUFIT implants are composed
of a poly( D , L -lactide- co -glycolide) polymer, formed into a bilayered
cylindrical scaffold that is absorbed by the body within six to nine
months, while Chondromimetic is a highly porous, collagen I-based
product within a mineral phase present in the region designed for