Multifunctional self-assembled Polyvinylalcohol materials for biomedical applications

Mircea Alexandru Mateescu¹, Wilms Baille¹, Grisel Luna Saavedra¹, Diana Averill²

¹ Department of Chemistry and CERMO-FC Centre, Faculty of Science, Université du Québec à Montréal, 

  Montreal (Québec) H3C 3P8, Canada. Contact-author e-mail: mateescu.m-alexandru@uqam.ca

² Department of Biological Science and CERMO-FC Centre, Faculty of Science, Université du Québec à 

  Montréal, (Québec) H3C 3P8, Canada.  Contact-author e-mail:  averill.diana_alison@uqam.ca

Introduction. Severe hepatic failure generates many deaths and the main solution to counteract this drastic condition is liver transplant. However, only 10% of the patients needing a liver transplant receive an organ.  Since hepatocytes account for about 80% of the liver's mass and exert most of its metabolic functions, their well-tailored three-dimensional aggregates are considered representative of liver tissue [1][2]. 

The isolated hepatocytes may lose their viability and metabolic functions, limiting their possibility of use for clinical, biopharmaceutical, engineering and research purposes. 

We are now proposing a new series of functionalized scaffolds based on polyvinyl alcohol (PVA) cross-linked by sodium trimetaphosphate (STMP) using an original two step method. 

Experimental. A volume of 100 mL of PVA (10 % solution) was first cross-linked with sodium trimeta-phosphate (STMP) at 20% (conventional degree). Various scaffolds based on PVA derivatives were prepared in the same conditions but also adding galactose, collagen, chitosan or modified starch (CM-Starch). Scaffold strips were placed into 12 well plates and seeded with isolated Rat (Sprague-Dawley) hepatocytes (2 x 10⁶ cells/strip). The obtained scaffolds were characterized by SEM, Solid state NMR, and viability of cell aggregates was established with the Lactate dehydrogenase (LDH) activity released in the medium. 

Resultants & Discussions. The proposed method produces high porous matrices (≥ 70 %) with a porosity distribution between 50-1000 μm. 

The re-organization of the cells as aggregates inside the connected pores generates certain aspects as a tissue-like structures. 

The addition of chitosan induced a higher efficiency of cellular adhesion in the 3D PVA microenvironment. 

Fig 1 - Top view of PVA-STMP-CMS

Scaffolds with aggregates at 48h after inoculation of 10⁶ hepatocytes (SEM voltage 15-30 kV)

Conclusions. The porous scaffolds were able to retain hepatocytes as aggregates (more than 80% adhesion) and viability of more than 50% (superior to the values reported for the 2D cultured cells. 

References. 

[1] Gevaert E., Dollé L., ... Cornelissen R. High Throughput Micro-Well Generation of Hepatocyte Micro-Aggregates for Tissue Engineering. PLOS ONE 2014, 9(11): e114315. 

[2] Saavedra YGL, Mateescu MA, Averill-Bates DA, Denizeau F. Polyvinylalcohol three-dimensional matrices for the improved long-term dynamic culture of hepatocytes. J Biomed Mater Res A 2003; 66: 562-570.