Smart lactate delivery from electro-responsive electrospun fibers

Abstract

The sustained administration of lactate for several days promotes mammalian cardiac tissue regeneration. In this work, electrical stimulation is used for tuning the kinetic release profile of electro-responsive fiber mats loaded with lactate, which are prepared from electrospun solutions containing polylactic acid (PLA), polyaniline (PAni) at different amounts (0.1–0.5 % w/w), and lactate. The resulting PLA/PAni fibers, with average diameters ranging between 1.9 and 2.3 μm, depending on the PAni content, are electroactive, biocompatible, and exhibit higher resistance to elastic deformation than PLA fibers. The release profiles obtained without and with electrical stimuli only show an uncontrolled burst lactate delivery, which is significantly boosted when a negative voltage is applied. Thus, electrical stimulation appears to promote the migration of lactate from the interior of the fibers to the surface, from where it is immediately released. In order to delay the lactate delivery and allow some control on the system, a polycaprolactone (PCL) coating was applied to the PLA/PAni fiber mats. Electrically stimulated PCL/PLA/PAni shows a controlled and sustained release of lactate, which is progressively delivered over time. While the burst release, which is similar without and with stimulation, is smaller for coated than for uncoated fibers, the application of a voltage to PCL/PLA/PAni provides an appreciable and sustained cumulative lactate release that increases linearly with time over nine days. This control, which is attributed to the effect of the voltage on the polyester altering its porosity, renders the electroactive lactate-loaded PLA/PAni fibers promising for cardiac tissue engineering applications.

This publication is part of the I + D + i project PID2021-125767OBI00 and CEX2023-001300-M funded by MCIN/AEI/10.13039/ 501100011033 and, as appropriate, by “ERDF A way of making Europe” and European Union Next Generation EU. P.A. Haro-Guti´errez is thanked to CONACYT (M´exico) for the financial support through a postgraduate scholarship (836603 CVU 347614). Support for the research of C.A. was also received through the prize “ICREA Academia” for excellence in research funded by the Generalitat de Catalunya.