Ionic Species Affect the Self-Propulsion of Urease-Powered Micromotors
Xavier Arqué,
Xavier Andrés,
Rafael Mestre,
Bernard Ciraulo,
Jaime Ortega Arroyo,
Romain Quidant,
Tania Patiño,
Samuel Sánchez
Affiliations
Xavier Arqué
Institute for Bioengineering of Catalonia (IBEC), The Barcelona Institute of Science and Technology (BIST), Baldiri i Reixac 10-12, 08028 Barcelona, Spain
Xavier Andrés
Institute for Bioengineering of Catalonia (IBEC), The Barcelona Institute of Science and Technology (BIST), Baldiri i Reixac 10-12, 08028 Barcelona, Spain
Rafael Mestre
Institute for Bioengineering of Catalonia (IBEC), The Barcelona Institute of Science and Technology (BIST), Baldiri i Reixac 10-12, 08028 Barcelona, Spain
Bernard Ciraulo
Institute of Photonic Sciences (ICFO), The Barcelona Institute of Science and Technology, Carl Friedrich Gauss 3, 08860 Castelldefels, Barcelona, Spain
Jaime Ortega Arroyo
Institute of Photonic Sciences (ICFO), The Barcelona Institute of Science and Technology, Carl Friedrich Gauss 3, 08860 Castelldefels, Barcelona, Spain
Romain Quidant
Institute of Photonic Sciences (ICFO), The Barcelona Institute of Science and Technology, Carl Friedrich Gauss 3, 08860 Castelldefels, Barcelona, Spain; Institució Catalana de Recerca i Estudis Avançats (ICREA), Pg. Lluís Companys 23, 08010 Barcelona, Spain
Tania Patiño
Institute for Bioengineering of Catalonia (IBEC), The Barcelona Institute of Science and Technology (BIST), Baldiri i Reixac 10-12, 08028 Barcelona, Spain; Chemistry Department, University of Rome, Tor Vergata, Via della Ricerca Scientifica, 00133 Rome, Italy
Samuel Sánchez
Institute for Bioengineering of Catalonia (IBEC), The Barcelona Institute of Science and Technology (BIST), Baldiri i Reixac 10-12, 08028 Barcelona, Spain; Institució Catalana de Recerca i Estudis Avançats (ICREA), Pg. Lluís Companys 23, 08010 Barcelona, Spain
Enzyme-powered motors self-propel through the catalysis of in situ bioavailable fuels, which makes them excellent candidates for biomedical applications. However, fundamental issues like their motion in biological fluids and the understanding of the propulsion mechanism are critical aspects to be tackled before a future application in biomedicine. Herein, we investigated the physicochemical effects of ionic species on the self-propulsion of urease-powered micromotors. Results showed that the presence of PBS, NaOH, NaCl, and HEPES reduced self-propulsion of urease-powered micromotors pointing towards ion-dependent mechanisms of motion. We studied the 3D motion of urease micromotors using digital holographic microscopy to rule out any motor-surface interaction as the cause of motion decay when salts are present in the media. In order to protect and minimize the negative effect of ionic species on micromotors’ performance, we coated the motors with methoxypolyethylene glycol amine (mPEG) showing higher speed compared to noncoated motors at intermediate ionic concentrations. These results provide new insights into the mechanism of urease-powered micromotors, study the effect of ionic media, and contribute with potential solutions to mitigate the reduction of mobility of enzyme-powered micromotors.
