Microfluidics-interfaced capillary electrophoresis coupled with modular LED-based fluorescent detection: A new tool for continuous monitoring of the interaction between nanoparticles and bio-entities

This study reports on the development of a novel modular microfluidic capillary electrophoresis (MMCE) platform with LED-based fluorescent (LEDIF) detection for automatic sampling and analysis purpose. The MMCE-LEDIF design is based on unprecedented ‘plugging’ hyphenation of various off-the-shelf parts available for microfluidics, optics and electrophoresis, allowing the users to construct their own analytical device without requirement of mechanical and electronic workshop facilities. The detection module relies on a LED source to generate a defined excitation wavelength, which can be focused on an optical window along the separation capillary to excite the separated target molecules. For automatic sampling and analysis, pneumatically driven modules were coupled with capillary electrophoresis (CE) to replace the conventional sequential injection analysis (SIA)-CE setup, allowing continuous flow circulation (to mimic a bio-fluid circulation) and pulseless sample delivery and injection for analysis. The MMCE-LEDIF platform was applied for separation and fluorescent detection of tailored and functionalized magnetic nanoparticles, as well as monitoring of their interaction with dopamine to evaluate their potential as drug delivery nanoplatforms. Such operation was carried out in a continuous microflow of artificial cerebrospinal fluid to investigate their behavior in a bio-fluid mimicking environment. • Microfluidics-interfaced capillary electrophoresis instrument for analysis of flowing samples. • Sequential injections for monitoring of the interaction in a continuous microflow. • A new fluorescent detection setup with an LED source. • An at-line process analytical tool with sample treatment, separation and detection. • Study on the interaction between magnetic NPs and dopamine in artificial CSF.