Scalable Chemical Synthesis Route to Manufacture pH-Responsive Janus CaCO3 Micromotors

A cost-effective scalable chemical route to produce pH-responsive active colloids (ACs) is developed here. For the first time, calcium carbonate particles are half-coated with a silica layer via Pickering emulsion methodology. This methodology allows to create anisotropy on the particles' surfaces and benefit from the decomposition of the calcium carbonate in acidic media to generate self-propulsion. The coupling between the self-diffusiophoretic motion of these ACs and acid concentrations is experimentally investigated in Newtonian media via optical microscopy. With increasing hydrogen-ion concentrations, the pH-responsive colloids experience higher mean-square displacements because of self-propulsion velocities and enhanced long-time diffusivities. Because they are biocompatible and environmentally friendly, these ACs constitute a platform for advanced diagnostics, targeted drug delivery, and water/soil remediation.

在此开发了一种具有成本效益的可扩展化学方法来生产pH响应活性胶体（ACs）。首次通过皮克林乳液法用二氧化硅层半包覆碳酸钙颗粒。这种方法能够在颗粒表面产生各向异性，并利用碳酸钙在酸性介质中的分解来产生自推进力。通过光学显微镜在牛顿流体介质中对这些活性胶体的自扩散泳动与酸浓度之间的耦合进行了实验研究。随着氢离子浓度的增加，由于自推进速度和长时间扩散率的提高，pH响应胶体的均方位移更大。由于这些活性胶体具有生物相容性且对环境友好，它们构成了用于先进诊断、靶向药物递送以及水/土壤修复的平台。