Conductive fibers for biomedical applications

Bioelectricity has been stated as a key factor in regulating cell activity and tissue function in electroactive tissues.Thus,various biomedical electronic constructs have been developed to interfere with cell behaviors to promote tissue regeneration,or to interface with cells or tissue/organ surfaces to acquire physiological status via electrical signals.Benefiting from the outstanding advantages of flexibility,structural diversity,customizable mechanical properties,and tunable distribution of conductive components,conductive fibers are able to avoid the damage-inducing mechanical mismatch between the construct and the biological environment,in return to ensure stable functioning of such constructs during physiological deformation.Herein,this review starts by presenting current fabrication technologies of conductive fibers including wet spinning,microfluidic spinning,electrospinning and 3D printing as well as surface modification on fibers and fiber assemblies.To provide an update on the biomedical applications of conductive fibers and fiber assemblies,we further elaborate conductive fibrous constructs utilized in tissue engineering and regeneration,implantable healthcare bioelectronics,and wearable healthcare bioelectronics.To conclude,current challenges and future perspectives of biomedical electronic constructs built by conductive fibers are discussed.

Ultrastretchable and wearable conductive multifilament enabled by buckled polypyrrole structure in parallel

Stretchable conductive fibers have attracted much attention due to their potential use in wearable electronics.However,the ultrahigh strain insensitive conductivity is hindered by mechanical mismatch in Young’s modulus and failure of stretchable structures under large deformation.This challenge is addressed with a conductive and elastic multifilament made of the polyurethane monofilaments that are surface-coated with buckled polypyrrole(PPy)of which flexibility is improved by sodium sulfosalicylate.Such parallel conductive monofilaments with PPy buckling on surface reduce the influence of cracks in the conductive coating on the overall conductivity,displaying an ultra-high strain insensitive behavior(quality factor Q=10.9).Remarkably,various complex forms of wearable electronic textiles made by this conductive multifilament maintain the strain-insensitive behavior of the original multifilament,even upon the large deformation of human joint.This multifilament with wrinkled PPy has attractive advantages in the application of super-stretched wearable electronic devices.