Multi-layer patch with aligned poly (acrylonitrile-co-acrylic acid) nanofibers for lactate detection in human sweat

•Aligned nanofibers of poly (acrylonitrile-co-acrylic acid) for lactate detection.•9:1 acrylonitrile:acrylic acid shows lowest resistance and better consistency.•Aligned hydrophilic nanofibers spun on copper cotton fabric.•Three layer sensor with hydrophobic top layer to improve sweat distribution.•Linear correlation in sensing (0.94) from 27 to 270 ppm of lactate dosage in sweat.