“The home pregnancy test is an excellent example of how nano-properties can be used to provide practical solutions to real-world problems.”

“The story behind some of the color-change urine dipstick tests is a great example. The short answer is that a pregnant woman's urine has a significant excess of HcG, human gonadotropic hormone. This hormone has a certain protein structure that binds to a complementary DNA base pair sequence. That very specific complementary lock for the HcG key is attached to gold nanoparticles which reflect light of a specific color. If HcG is detected, the spot or line reflects red; if not, blue or clear or whatever the design entails.”

“Of course, upgrades in cosmetics could lead to the use of the "First Responder" home-pregnancy test manufactured by Carter-Wallace, the New York based biotechnology company. The test uses gold particles (less than 50 nanometers in diameter) to help consumers read test results more easily.”