Microfluidic Processing of Piezoelectric and Magnetic Responsive Electroactive Microspheres

Abstract

Poly(vinylidene fluoride) (PVDF) combined with cobalt ferrite (CFO) particles is one of the most common and effective polymeric magnetoelectric composites. Processing PVDF into its electroactive phase is a mandatory condition for featuring electroactive behavior and specific (post)processing may be needed to achieve this state, although electroactive phase crystallization is favored at processing temperatures below 60 °C. Different techniques are used to process PVDF−CFO nanocomposite structures into microspheres with high CFO dispersion, with microfluidics adding the advantages of high reproducibility, size tunability, and time and resource efficiency. In this work, magnetoelectric microspheres are produced in a one-step approach. We describe the production of high content electroactive phase PVDF and PVDF−CFO microspheres using microfluidic technology. A flow-focusing polydimethylsiloxane device is fabricated based on a 3D printed polylactic acid master, which enables the production of spherical microspheres with mean diameters ranging from 80 to 330 μm. The microspheres feature internal and external cavernous structures and good CFO distribution with an encapsulation efficacy of 80% and prove to be in the electroactive γ-phase with a mean content of 75%. The microspheres produced using this approach show suitable characteristics as active materials for tissue regeneration strategies and other piezoelectric polymer applications.

Stimuli-responsive microcarriers and their application in tissue repair: A review of magnetic and electroactive microcarrier

“…In other words, microcarriers with surface charges can move directionally in an external EF [ 141 ], free electrons in microcarriers based on conductive materials can also move to form an electric current by the drive of an EF, and the current will be transported to the tissue. Piezoelectric materials-based microcarriers can deform in response to external stimuli, such as mechanical stress, ultrasound, and MF [ [143] , [144] , [145] ], resulting in charge accumulation and polarization. For example, Zhang et al [ 146 ] prepared a magnetoelectric core-shell structure composed of Fe 3 O 4 and BaTiO 3 to reproduce the magnetoelectric characteristics of the natural neural extracellular matrix.…”

Magnetostrictive and Magnetoactive Effects in Piezoelectric Polymer Composites

“…When producing PVDF-based composite films, CFO nanoparticles are added to the yet non-solidified polymer, then the mixture is stirred up to homogenize and finally dried, see [ 15 , 16 , 17 , 18 ], for example. The working conditions for such magnetostrictive films are set with the aid of a constant magnetic (bias) field .…”

Electrochemical-Based Biosensor Platforms in Lab-Chip Models for Point-of-Need Toxicant Analysis

“…Amongst the different innovative technologies, microelectromechanical system (MEMS)based microfluidics has emerged as a valuable tool to provide solutions for analytical science research problems. Externally controllable micropumps and valves integrated with electronic, electrochemical, and piezoelectric/magnetic sensors and actuators are emerging innovations in microfluidic-based analytical applications [8][9][10][11]. The amalgamation of electrochemical techniques into a lab-on-chip (LOC) environment makes the detection platform more suitable for handling a low volume of reagents, a precise target-bioreceptor interaction, and a rapid analytical response.…”