Most diagnostic blood tests require the samples to be kept stable from the time they are drawn. This often involves expensive refrigeration units, especially if the sample is not taken near a testing facility. Recently, a team at Tufts University in Boston has demonstrated that when silk fibers are dissolved in a blood sample they stabilize the biological components of the sample, which can then be dried and transported at ambient temperatures. This preserves the structure of blood proteins which can then be tested by re-hydrating the sample at a later date.
Read more about this fascinating research in an article from STAT: https://www.statnews.com/2016/05/09/blood-silk-diagnostics/