In vitro neuronal and glial response to magnetically stimulated piezoelectric poly(hydroxybutyrate-co-hydroxyvalerate) (PHBV)/cobalt ferrite (CFO) microspheres.

Polymer biomaterials are being considered for tissue regeneration due to the possibility of resembling different extracellular matrix characteristics. However, most current scaffolds cannot respond to physical-chemical modifications of the cell microenvironment. Stimuli-responsive materials, such as electroactive smart polymers, are increasingly gaining attention once they can produce electrical potentials without external power supplies. The presence of piezoelectricity in human tissues like cartilage and bone highlights the importance of electrical stimulation in physiological conditions. Although poly(vinylidene fluoride) (PVDF) is one of the piezoelectric polymers with the highest piezoelectric response, it is not biodegradable. Poly(hydroxybutyrate-co-hydroxyvalerate) (PHBV) is a promising copolymer of poly(hydroxybutyrate) (PHB) for tissue engineering and regeneration applications. It offers biodegradability, piezoelectric properties, biocompatibility, and bioactivity, making it a superior option to PVDF for biomedical purposes requiring biodegradability. Magnetoelectric polymer composites can be made by combining magnetostrictive particles and piezoelectric polymers to further tune their properties for tissue regeneration. These composites convert magnetic stimuli into electrical stimuli, generating local electrical potentials for various applications. Cobalt ferrites (CFO) and piezoelectric polymers have been combined and processed into different morphologies, maintaining biocompatibility for tissue engineering. The present work studied how PHBV/CFO microspheres affected neural and glial response in spinal cord cultures. It is expected that the electrical signals generated by these microspheres due to their magnetoelectric nature could aid in tissue regeneration and repair. PHBV/CFO microspheres were not cytotoxic and were able to impact neurite outgrowth and promote neuronal differentiation. Furthermore, PHBV/CFO microspheres led to microglia activation and induced the release of several bioactive molecules. Importantly, magnetically stimulated microspheres ameliorated cell viability after an in vitro ROS-induced lesion of spinal cord cultures, which suggests a beneficial effect on tissue regeneration and repair.

Fluorinated Polymer Membranes as Advanced Substrates for Portable Analytical Systems and Their Proof of Concept for Colorimetric Bioassays.

Portable analytical systems are increasingly required for clinical analysis or environmental monitoring, among others, being materials with tailored physicochemical properties among the main needs for successful functional implementation. This article describes the processing of fluorinated poly(vinylidene-co-trifluorethylene), P(VDF-TrFE), membranes with tailored morphological and physicochemical properties to be used as microfluidic substrates for portable analytical systems, commonly called point-of-care systems in the medical field. The morphology of the developed membranes includes spherulitic, porous, randomly oriented, and oriented fibers. Furthermore, the processed hydrophobic P(VDF-TrFE) membranes were post-treated by oxygen plasma to make them superhydrophilic. The influence of morphology and plasma treatment on the physicochemical properties and capillary flow rates was evaluated. Microfluidic systems were then designed and printed by wax printing for the colorimetric quantification of glucose. The systems comprise eight reaction chambers, each glucose concentration (25, 50, 75, and 100 mg dL-1) being measured in two reaction chambers separately and at the same time. The results demonstrate the suitability of the developed microfluidic substrates based on their tailorable morphology, improved capillary flow rate, wax print quality, homogeneous generation of colorimetric reaction, and excellent mechanical properties. Finally, the possibility of being reused, along with their electroactive properties, can lead to a new generation of microfluidic substrates based on fluorinated membranes.