Main goal

1

University of Minho School of Engineering ltNome do Centrogt
ASSEMBLY OF PLATELET LYSATE-LOADED NANOPARTICLES
AS A NEW HYDROGEL SYSTEM FOR CARTILAGE TISSUE
ENGINEERING
VITOR E. SANTO, ELENA G. POPA Supervisors
Rui L. Reis, João F. Mano and Manuela E. Gomes
v.espirito.santo_at_dep.uminho.pt
Results and Discussion
Main goal To develop a new hydrogel for
application in the cartilage tissue engineering
field through the self-assembly of nanoparticles
loaded with growth factors enabled throught the
use of platelets lysates (PL) in two aways (i)
source of growth factors and (ii) as connecting
hydrogel matrix. Introduction The cartilage
tissue engineering (TE) strategy described in
this work relies on the combination of natural
polymer-based nanoparticles (NPs), produced from
the complexation of chitosan (CH) with
chondroitin sulfate (CS), for the incorporation
and sustained release of bioactive agents, namely
platelet lysate (PL). The CH/CS complex mimics
the extracellular matrix (ECM) interactions and
PL is an autologous source of a cocktail of GFs
acting on tissue healing and repair. When used at
determined concentrations, the PL-releasing NPs
can assemble in a simple and quick mode to form a
three-dimensional (3D) stable hydrogel while in
suspension with human Adipose derived Stem Cells
(hASCs), following a mild centrifugation,
allowing the cells to be entrapped in this
enriched 3D environment.
Materials Methods Formulations (i)
hASCs pellets (ii) assembled empty NPs hASCs
(iii) assembled PL-loaded NPs
hASCs. Characterization (i) In vitro GF release
(ii)Histology Hematoxylin Eosin (HE), alcian
blue and safranin-O (iii) real time Polymerase
Chain Reaction (rt-PCR) for evaluation of
collagen type II and type I gene expression.

2. Histological Characterization
2. Assembly of PL-loaded Nanoparticles for hASCs
entrapment
hASCs PL loaded NPs hASCs empty NPs
hASCs pellets
HE Alcian Blue Safranin-O
100µm
3. In vitro culture under chondrogenic stimulus
The HE staining reveals that after 28 days, the
stability of the PL-loaded NPs hydrogel is higher
in comparison with the empty NPs. Moreover, we
can observe the formation of cartilage ECM
comparable with the positive control.
3. Real time PCR chondrogenic gene expression
Materials and Methods
Results and Discussion
1. Nanoparticles Production and Platelet Lysate
Adsorption
The scaffolds loaded with PL showed a stronger
upregulation of col II in comparison with col I,
showing the formation of hyaline articular
cartilage ECM.
The GF release profile for PDGF-BB and TGF-ß1 is
characterized by a strong burst release at day 1,
followed by a more controlled delivery during the
remaining days. After day 7, the GF release was
undetectable.
1. In vitro GF release

Conclusions
Polyelectrolyte Complexation
The presence of PLs in the 3D matrix enhances the
in vitro chondrogenic diferentiation of hASCs.
PLs have a multifunctional role as a
connective/stability agent for the matrix and as
a GFs supplier for chondrogenic differentiation,
creating an effective hydrogel network for
cartilage TE..
CH in acetic acid
CS in distilled water
Centrifugation and resuspension
PL Adsorption
Acknowledgments The authors thank the FCT grants
(SFRH/BD/39486/2007 and SFRH/BD/64070/2009), the
European projects (NMP3-CT-2004-500283 and
NMP4-SL-2009-229292), IPS and Hospital da
Prelada.
Uma Escola a Reinventar o Futuro Semana da Escola de Engenharia - 24 a 27 de Outubro de 2011