Alginate/silica hybrid materials for immobilization of green microalgae Chlorella vulgaris for cell-based sensor arrays

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 Ca 2+ -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.

Synergistically strengthened 3D micro-scavenger cage adsorbent for selective removal of radioactive cesium

“…Thus, pure Ca-alginate could not be used in seawater as an adsorbent for the removal of radioactive cesium. Especially in a marine environment, Ca 2+ ions are easily detached by the chelating agents and monovalent ions, such as Na + and K + , found in seawater, which results in destabilization of the alginate matrix20. Figure S10 and Figure S11 shows the amount of PB released from PB/Ca-alginate bead, PB/Fe-alginate bead, and P-MSC composite in DI water and seawater.…”

“…Although alginate hydrogels have been extensively studied for adsorption applications, their use has been restricted by their poor mechanical properties and low adsorption capacities51819. Especially in a marine environment treatment process, the calcium ions are easily detached by chelating agents and monovalent ions, such as Na + and K + , that are found in seawater, which results in destabilization of the alginate matrix20.…”

Understanding and Tuning Bioinorganic Interfaces for the Design of Bionanocomposites

“…It must be pointed out that induction of alginate gelation by use only of silica particles has not been reported so far. It could only be achieved by use of tetrakis(2‐hydroxyethyl)orthosilicate (THEOS), a water‐soluble silicon alkoxide,103 and (3‐aminopropyl)triethoxysilane (APTES) 104…”

Effect of different irradiance levels on bioelectricity generation from algal biophotovoltaic (BPV) devices

“…9,10 The energy oxidizes water molecules into molecular oxygen, protons, and electrons in the Photosystem II (PSII) oxygen-evolving complex (OEC). 17 Hence, it is commonly used to encapsulate algal cells for biomass retention and resistance against reaction with toxic materials. Electrons from the cells are ferried to the electrode through one of the following pathways: (a) direct electron transfer (DET), (b) an endogenous electron transfer mediator such as Flavin, or (c) an exogenous electron transfer mediator such as polypyrrole and polyaniline.…”