Talks and Poster Presentations (without Proceedings-Entry):
S. Baudis, Z. Tomasikova, X.H. Qin, P. Gruber, M. Markovic, J. Stampfl, A. Ovsianikov, R. Liska:
"Cell Encapsulation by Microfabrication with Hyaluronic Acid based Hydrogel Precursors";
Poster: International Conference on Biofabrication 2015,
Domplein 29, 3512 JE Utrecht;
Aim: Cell encapsulation plays a central role in many biofabrication methods. Photopolymerizable
hydrogels provide additional advantage of temporal and spatial control of encapsulation process. Such
characteristics of a photoinitiator (PI) as its water-solubility cytocompatibility spectral sensitivity and
initiation efficiency are vital to its performance and suitability for a particular application. The aim of this
study was to identify characterize and compare a new generation of water-soluble highly reactive and
biocompatible visible light photoinitiators (PIs).
Methods: The monomer 4-acryloylmorpholine (NAM) and the PI / coinitiator Quantacure BPQ (Q-BPQ)
methyldiethanolamine (MDEA) Irgacure 2959 (I2959) and APi-180 are commercially available (TCI Aldrich
3B Scientific Ciba and Shenzhen UV-ChemTech respectively) and were used in the highest purities
available. Na-TPO and Li-TPO were synthesized according to literature. Na-BAPO and Li-BAPO were
received from BASF where both were synthesized according to published procedures. Absorption
properties solubility storage stability cytotoxicity reactivity and efficiency in double bond conversion
(DBC) of these compounds were evaluated.
Results: The solubility is one of the most important characteristics of a PI for use in water based
formulations. While the state of the art PI I2959 and its modified version APi-180 suffer from very low
solubility they are substantially outperformed by the new generation MAPO and BAPO PIs. All
compounds showed adequate storage stability in neutral basic and acidic solvents. Viability of cells
exposed to different concentrations of PIs was shown to be in a similar range as I2959 widely used for cell
encapsulation. However absorption characteristics and reactivity of novel PIs around 320-500 nm are
superior. This difference in efficiency would potentially allow to use lower PI concentrations for cell
Conclusions: In this contribution we have shown that the MAPO and BAPO salts as next generation
water-borne photoinitiators not only show storage stability and biocompatibility in the same range as
state of the art photoinitiators but outperform them by a large margin in solubility and reactivity.
Furthermore it is possible to use the MAPO and BAPO salts as visible light initiators which is a
considerable advantage for applications involving living cells. A practical example of encapsulation of
MC3T3 preosteblast cells using I2959 and Li-TPO with 365nm source confirms these conclusions.
Created from the Publication Database of the Vienna University of Technology.