A three-dimensional and bevel-angled ultrahigh aspect ratio microneedle for minimally invasive and painless blood sampling

In spite of the invasiveness and pain related with it, blood sampling is necessary in point-of-care systems to obtain biochemical information. In this context, a substitute micro-scale needle for minimally invasive and painless blood sampling has been developed. In conventional microneedle fabrication methods, it is difficult to combine the features of a sharp tip shape, appropriate length, and a hollow structure simultaneously. Thus, here we report a sharp, hollow, and ultrahigh aspect ratio microneedle long enough to get to the blood vessels which is capable of minimizing the pain caused by nerve pricking. It is equipped with a fluidic system to handle blood. The structure of the microneedle was precisely formed using a drawing lithography method and a sharp angle tip was formed using a laser-cutting method.