Autor(es):
Canadas, Raphael Faustino 
; Pereira, D. R. ; Correia, Joana Silva ; Marques, A. P. ; Oliveira, Joaquim M. ; Reis, R. L.
Data: 2012
Identificador Persistente: http://hdl.handle.net/1822/24110
Origem: RepositóriUM - Universidade do Minho
Assunto(s): Bilayer structures; Osteochondral
Descrição
Osteoarthritis is a major cause of disability during aging. By the age of
60, close to 100% of the population will have histologic changes of
degeneration in their knee cartilage (Loeser, 2000). Because of its avascular
nature, cartilage has little capacity to self-regenerate. Despite the
progress already achieved in osteochondral regeneration, some limitations
have to be overcome. The formation of fibrocartilage has to be
avoided and the innervation has to be improved. Further, one main feature
to be promoted is the induction of vascularization in the bony part
but not in the cartilage part and to avoid de-differentiation processes. A
promising strategy could pass through the development and optimization
of novel culture systems. The ideal approach could integrate scaffolds
presenting regions with different physical characteristics,
combined with different growth factors to support different stem cells
fates, regarding the complex tissue physiology to be regenerate. This
work aims to develop novel bilayered gellan gum (GG)/gellan gumhydroxyapatite
(HAp) hydrogels based structures for osteochondral tissue
engineering applications. Bilayered GG/GG-HAp hydrogels were
produced by joining both solutions of GG 2% (w/v) with and without
HAp (20% wt.) for bony and cartilage parts, respectively. The solutions
were introduced into a silicone mould with 20:10 mm (height and
diameter, respectively). Gelation of GG was promoted by immersion in
PBS solution for 24 h. The architecture of the bilayered scaffolds was
investigated by micro-computed tomography. Results have shown that
the freeze-dried bilayered scaffolds composed by low acyl GG(2%(w/
v)/low acyl GG(2%(w/v)-HAp20%(w/w) possess a porosity of
83.4 ± 0.8%, pore size of 279.3 ± 38.6 lm and interconnectivity of
62.2 ± 5.4%. Degradability assays are being performed with the intent
to use this system to culture human adipose derived stem cells inducing
cell co-differentiation into chondrocytes and osteoblasts. Ultimately, the developed bilayered scaffolds will provide new therapeutic possibilities for the regeneration of osteochondral defects.
