Alginate/silica hybrid materials for immobilization of green microalgae Chlorella vulgaris for cellbased sensor arrays

Authors

Angela K. Pannier, University of Nebraska-LincolnFollow
Ulrich Soltmann, GMBU e.V., Department of Functional Coatings, D-01317 Dresden, Germany
Bettina Soltmann, Institute of Materials Science and Max Bergmann Center of Biomaterials, TU Dresden, D-01062 Dresden, Germany
Rolf Altenburger, UFZ Helmholtz Centre for Environmental Research, Department Bioanalytical Ecotoxicology, D-04318 Leipzig, Germany
Mechthild Schmitt-Jansen, UFZ Helmholtz Centre for Environmental Research, Department Bioanalytical Ecotoxicology, D-04318 Leipzig, Germany

Document Type

Article

Date of this Version

2014

Citation

J. Mater. Chem. B, 2014, 2, 7896–7909

Comments

This journal is © The Royal Society of Chemistry 2014. Used by permission

Abstract

Thin layers and patterned dot arrays of sodium alginate containing living microalgal cells were deposited onto glass carriers which were subsequently gelled using amino-functionalized silica sol to obtain reinforced alginate hydrogels. The resulting alginate/silica hybrid materials showed improved stability in salt-containing solutions compared to alginate gels gelled by traditional methods using Ca²⁺-ions. Cell arrays were patterned by printing nanolitre-scale drops of sodium alginate/cell suspension using a noncontact micro-dosage system which allows the printing of solutions of high viscosity. Cultures of the green microalga Chlorella vulgaris were immobilized within the newly developed alginate/silica hydrogels in order to demonstrate the potential of the hybrid matrix for the design of cell-based detection systems. The herbicide atrazine as well as copper ions have been used as model toxicants. Short-term toxicity tests (exposure time: 1 h) have been carried out using atrazine and changes in chlorophyll a (Chl a) fluorescence were measured by imaging pulse amplitude modulated-fluorometry (Imaging-PAM). C. vulgaris cells immobilized within alginate/silica hydrogels demonstrated a highly reproducible response pattern and compared well to freely suspended cells. Activity and response sensitivity of immobilized cells to atrazine was largely maintained for up to 8 weeks, especially when stored under cool conditions in the dark. Furthermore, immobilized cells could be repeatingly used for short-term toxicity tests as atrazine produces a reversible inhibition of photosynthesis.