A Swiss research team revealed a big new step in that field: a super-thin circuit that can function while wrapped around a human hair or laid on a contact lens.
The team, led by Giovanni Salvatore at the Swiss Federal Institute of Technology, created a circuit on a parylene film just a single micrometer thick.
That's about one sixtieth the thickness of a human hair. The scientists achieved this by building the circuit on a vinyl polymer base that's then dissolved away, leaving the ultra-thin, ultra-flexible circuit intact.
The resulting circuit can be draped over human hair, plastered on human skin, or pasted on a plant leaf, without cracking or losing conductivity, as show in these images from the research paper published in Nature Communications:
Applications for such technology sound positively sci-fi: the Swiss research team envisions a transparent circuit on a contact lens to sense the increased pressure in the eye that causes glaucoma. Other applications could include implanted sensors that continually monitor blood pressure in heart patients.