KAARINA AITAMURTO ALEKSANTERI INSTITUTE [email protected] SOUTHERN AND EASTERN MIGRANTS IN RUSSIA.
Electrospun nanofibers at University of Helsinki Dr. Antti Laukkanen 8.2.2007 DDTC Drug Discovery...
Transcript of Electrospun nanofibers at University of Helsinki Dr. Antti Laukkanen 8.2.2007 DDTC Drug Discovery...
Electrospun nanofibers at University of Helsinki
Dr. Antti Laukkanen
8.2.2007
DDTC
Drug Discovery and Development Technology Center
Cell Culture Models
On filter, for example Toropainen et al.:
Culture model of human corneal epithelium for prediction of
ocular drug absorption
Toropainen E, Ranta VP, Talvitie A, Suhonen P, Urtti A: Invest Ophthalmol Vis Sci., 2001, 42, 2942-2948.
More difficult with other cell types which need truly 3D
environment
Extra Cellular Matrix – Should we try to mimic it?
Griffith L. and Swartz M., Nature Reviews, 216 (7), 2006
Advanced matrices
Schematic drawing of an artificial mimic of an extracellular matrix. The fibrillar skeleton is composed of electrospun biodegradable polymer fibers. The matrix is modified by incorporating cell adhesion ligands on the surface of nanofibers to improve the cell attachment. Hydrophilicity is increased with grafted polymer chains and the cell culturing is controlled with a controlled release of growth factors.
Advanced matrices
1. Electrospinning of functional polymers
2. Post-modification with peptides or direct solid phase
synthesis
Functional polymers and functional fibers
What is the needed functionality? Fiber should be cross-linkable or water insoluble
, UV, or plasma treatment What other solvents should be tolerated?
OH
Cl
NH
NH2
OH
Fibers for solid phase synthesis
Need for highly stable amino functionalized polymer Should tolerate DMF and NMP
Cl Cl
NH2
NH2
NH
NH2
+Toluene, 35 - 70 °C48 h + 2 h
Toluene60 °C
AIBN
Synthesis route of amino-functional poly(styrene). The amino-modification could be conducted before or after the electrospinning.
The role 1,4 diaminobutane is twofold: first it will provide the needed amino-functionality on the fibers and secondly it will slightly cross-link the nanofibers. The degree of cross-linking is dependent on the relative amounts of diamine and chloromethyl functionality in the modification reaction.
Electrospinning Instrumentation
V
Polymer solution
Needle
High voltage power supply
Collector
+++
++
+++
Taylor cone Simplified set-up
The Electrospinning device
Pore size 20-30 m
PVP Nanofibers
PEVA Nanofibers
Water insoluble – stable in physiological conditions Fiber diameter 1 -2 m, pore size 20-40 m Easily modified via hydroxyl group Possibility to graft other chains by redox polymerization
OH
0.27 0.73