Positive Effect of Magnetic-Conductive Bifunctional Fibrous Scaffolds on Guiding Double Electrical and Magnetic Stimulations to Pre-Osteoblasts

Development of bone tissue engineering has provided a promising method for bone rehabilitation. Tissue engineering scaffolds with magnetic or conductive properties may conduct electric or magnetic signals and bring out synergetic promoting effect to cells growth. In this work, polypyrrole (PPy)/Fe₃O₄/polylactic acid-glycolic acid (PLGA) magnetic-conductive bifunctional fibrous scaffolds were prepared through in-situ polymerization of pyrrole on Fe₃O₄/PLGA fibers. The prepared magnetic-conductive bifunctional PPy/Fe₃O₄/PLGA fibrous scaffolds showed good conductive and magnetic properties to deliver electrical and magnetic signals. The PPy/Fe₃O₄/PLGA fibrous scaffolds had a conductivity of 0.58 S/cm at 180 mM pyrrole and still remained with good fibrous morphology. MC3T3-E1 pre-osteoblasts inoculated on PPy/Fe₃O₄/ PLGA scaffolds under double electrical stimulation (ES) and magnetic stimulation (MS) demonstrated highest cell viabilities compared with those under single ES, MS or without any stimulation. The enhancement of cell viabilities by the Fe₃O₄/PLGA and PPy/Fe₃O₄/PLGA fibrous scaffolds from 1 to 5 d culture indicate that both of them had good biocompatibility. MS can also induce cell alignment arrangement on the magnetic scaffolds according to resultant cell scanning electron microscope (SEM) images. In addition, better hydrophilicity and thermal stability of the PPy/Fe₃O₄/PLGA fibrous scaffolds, as compared to Fe₃O₄/PLGA fibrous scaffolds, allowed the bifunctional scaffolds wide application in bone tissue engineering.