Local Light-Controlled Generation of Calcium Carbonate and Barium Carbonate Biomorphs via Photochemical Stimulation

The authors thank the European Research Council under the European Union's Seventh Framework Program (FP7/20072013)/ERC grant agreement no 340863 and ERC PoC LACRYS (837874) as well as Junta de Andalucia for financing the project P18-FR-5008. HC thanks the Deutsche Forschungsgemeinschaft DFG for financial support of the work on Biomorphs (CO 194/28-1). M.M., A.M., and A.M.-P. thank MIUR, (PRIN 2017) 2017E44A9P. Open access funding enabled and organized by Projekt DEAL.
Photochemical activation is proposed as a general method for controlling the crystallization of sparingly soluble carbonates in space and time. The photogeneration of carbonate in an alkaline environment is achieved upon photo-decarboxylation of an organic precursor by using a conventional 365 nm UV LED. Local irradiation was conducted focusing the LED light on a 300 μm radius spot on a closed glass crystallization cell. The precursor solution was optimized to avoid the precipitation of the photoreaction organic byproducts and prevent photo-induced pH changes to achieve the formation of calcium carbonate only in the corresponding irradiated area. The crystallization was monitored in real-time by time-lapse imaging. The method is also shown to work in gels. Similarly, it was also shown to photo-activate locally the formation of barium carbonate biomorphs. In the last case, the morphology of these biomimetic structures was tuned by changing the irradiation intensity.
European Research Council under the European Union's Seventh Framework Program (FP7/20072013)/ERC grant 340863
ERC PoC LACRYS 837874
Junta de Andalucia P18-FR-5008
German Research Foundation (DFG) CO 194/28-1
Ministry of Education, Universities and Research (MIUR)
Research Projects of National Relevance (PRIN) 2017E44A9P
Projekt DEAL