Autor(es):
Lima, A. C. 
; Custódio, Catarina A. ; Alvarez-Lorenzo, Carmen ; Mano, J. F.
Data: 2012
Identificador Persistente: http://hdl.handle.net/1822/24045
Origem: RepositóriUM - Universidade do Minho
Assunto(s): Spherical particles; Superhydrophobic surfaces; Tisssue engineering
Descrição
Encapsulating technologies that render spherical particles containing
cells or relevant moleculeshave been developed to be used in fields
such as tissue engineering, pharmaceutics, cosmetics, agriculture, as
also in other bio-related applications, namely biosensors and bioreactors.
The multiple bioactive agents release, with an important role in
tissue regeneration, constitutes an important strategy in tissue engineering.
The control of bioactive agents release may be achieved
increasing the complexity of the encapsulating particles by adjusting
the chemistry and the architecture. In this context, multi-compartmentalized
systems able to simultaneously deliver various bioactive agents
at different kinetics have emerged and are envisioned to be the next
area of development. Multilayered particles exhibiting predefined
diameters and layers thickness may offer additional advantages including
higher bioactive agents loads, improved molecules stability, and tailored
release schedules such as delayed or pulsatile avoiding initial
bursts. The most external layers could even act as rate-limiting barriers
to further reduce burst release. Since multilayered particles are compartmented,
each particle can load multiple bioactive agents isolated
from each other. Similarly, more than one type of cells may be immobilized
into different compartments. The layers thickness and composition
determine the performance of the system. Compared to
monocompartment delivery systems, the development of multi-compartmented
structures is still immature and intensive efforts are being
done to efficiently produce this type of systems. The production of
multi-compartmented particles is quite challenging and the existing
methodologies involve wet and aggressive conditions that compromise
the encapsulation efficiency of bioactive agents and the viability of
cells. Herein we report a simple bottom-up approach suitable for preparing
multilayered polymeric particles in a very fast way, which
involves the use of biomimetic superhydrophobic surfaces. In the present
work, concentric multilayered polymeric particles were prepared by
adding layers one-by-one, and then their applications as carriers for
sequential multiple drug release and as scaffolds for cells immobilization
intended in cell therapies or tissue engineering were explored. The
results showed that the engineered particles can be loaded with different
molecules confined in different compartments for later sequential
and time-programmed release. They can also immobilize cells maintaining
them viable for long time, being potentially useful for cell-based
therapies.
