https://iopscience.iop.org/article/10.1088/2516-1091/abe6f8/meta https://iopscience.iop.org/article/10.1088/2516-1091/abe6f8/... There are bloodless sensors no

https://iopscience.iop.org/article/10.1088/2516-1091/abe6f8/meta https://iopscience.iop.org/article/10.1088/2516-1091/abe6f8/... There are bloodless sensors now and in development.