Abstracts Book - IMRC 2018

• SB3-O008
IMPACT OF THE HYDRATION STATES OF POLYMERS ON THEIR
BIOCOMPATIBILITY
Loreto Valenzuela 1,2 , Min Bag 1
1 Pontificia Universidad Catolica de Chile, Chemical and Bioprocessing Engineering, Chile.
2
Pontificia Universidad Catolica de Chile, Institute for Biological and Medical Engineering, Chile.
In general, more hydrophobic polymers absorb less water, promoting protein
adsorption, cell adhesion, cell attachment, proliferation and differentiation.
However, not only the amount of water absorbed is related to its capacity of
adsorbing proteins, but also its state. Three states of water have been previously
described: non-freezable water is the tightly bound water to the surface, which
does not freeze even at -100°C; intermediate water interacts with the surface
but weaker than the non-freezable and freezes below 0°C; and, free water is the
one with less interaction with the surface and freezes at 0°C like bulk water. In
this work, we analyzed the correlation between the amount of water in the
different states at a polymer surface and the biocompatibility of that surface.
For polyarylates, at high water content, high freezable water relates directly with
fibrinogen adsorption and platelet adhesion, relationship that was not observed
in low water content polymers. In general, when intermediate water is present,
high hemocompatibility is observed (i.e., low platelet adhesion). More precisely,
intermediate water content higher than 3% wt relates to low platelet adhesion
and higher hemocompatibility than those with less or none. Intermediate water
in the polymer is more stable and has higher mobility than free water,
preventing protein activation by avoiding direct contact between non-freezable
water and the proteins. This relation has been observed in poly(ethylene glycol)
(PEG); poly(meth)acrylates (where poly(2-methoxyethyl acrylate) (PMEA) does
not present intermediate water and has high hemocompatibility); aliphatic
carbonyls and poly(lactic-co-glycolic acid) (PLGA). These findings help
understand polymer biocompatibility helping in the design of medical
applications. Further studies should include the interaction between water
molecules and polymer structure, and by those means, better understand its
mechanism of absorption.
Acknowledgment: This work was supported by FONDECYT grant No. 11121392.
Keywords: hydration, biocompatibility, intermediate water
Presenting authors email: lvalenzr@ing.puc.cl