Mass transport limitations of particulates within conventional microanalytical systems are often cited as the root cause for low sensitivity but can be overcome by directed analyte transport, such as via biomolecular motors or gradient surfaces. An ongoing challenge is the development of materials that are passive in nature (i.e., no external power source required), but can reconfigure to perform work, such as transporting particle-based analytes. Mimicking biology's concepts of autonomous and reconfigurable materials systems, like the Drosera capensis leaf, reconfigurable fiber networks that effectively concentrate particulates within a localized spot that can act as a detection patch are developed. These networks, prepared by electrohydrodynamic co-jetting, draw their reconfigurability from a bicompartmental fiber architecture. Upon exposure to neutral pH, a differential swelling of both fiber compartments gives rise to interfacial tension and ultimately results in shape reconfiguration of the fiber network. Compared to free particles, the reconfigurable fiber networks display a 57-fold increase in analyte detectability, average transport efficiencies of 91.9 ± 2.4%, and separation selectivity between different surface properties of 95 ± 3%. The integration of biomimetic materials into microanalytical systems, exemplified in this study, offers ample opportunities to design novel and effective detection schemes that circumvent mass transport limitations.

Fluidized particle electrodes are well-suited for a wide range of electrochemical reactions due to their large specific surface area and their tolerance toward suspended solid contaminants and gas bubbles. For effective electrode performance, particles require (i) high conductivity, (ii) efficient interparticle contact, and (iii) chemical inertness toward a broad range of reagents and solvents. In particular, sufficient interparticle contact remains a critical challenge. Magnetic stabilization of the fluidized bed provides a potential solution but requires the use of magnetic electrode materials. However, the synthesis of electrode particles with high magnetic susceptibility remains an ongoing challenge. Herein, electrojetting of magnetite/poly(methyl methacrylate) suspensions into a graphite powder bed is demonstrated to be a facile and effective route toward magnetically stabilizable electrode particles. Energy-dispersive X-ray spectroscopy and Raman spectroscopy confirmed the composition and core−shell structure of the particles. Characterization of their magnetic and electric properties showed an exceptionally high saturation magnetization of 11.1 A•m 2 /kg and a conductivity of 28 S/m. Further, scanning electron microscopy revealed an average diameter of approximately 200 μm, large surface areas, and spherical shapes, three prerequisites for homogeneous fluidization. Compared to previously reported fluidized bed electrodes, electrodes comprised of these novel core/shell particles showed 2-fold increases in current densities and conversion rates. These results underline the potential of the electrohydrodynamic jetting process for the design and synthesis of novel, tailor-made core−shell particles as key components of fluidized bed electrodes for electrochemical reactions.