Evaluation of a drop-on-demand micro-dispensing system for development of artificial fingerprints

Abstract

Precision micro-dispensing is an evolving technique that has many applications in the scientific and additive manufacturing communities. Here we describe a method for dispensing viscous materials, including the oily substance found in human fingerprints, known as sebum. In this work, a dispense jet system was used to deposit known amounts of sebum onto surfaces to represent an artificial human fingerprint. Ultraviolet-visible spectrophotometry (UV-Vis) and microgravimetry were used to verify the sebum mass loadings of the samples. The dispense jet was capable of printing a viscous sebum mixture as well as a less viscous solution of sebum dissolved in heptane. This method was shown to be repeatable, and UV-Vis was found to be a simple and useful technique for verifying the mass of sebum deposited. This method could be used to prepare artificial fingerprint samples for a variety of applications including the preparation of test materials for emerging trace detection technologies.