Scientists at Northwestern University have developed a new detection technology on the nanometer scale that could lead to the next generation of proteomic arrays and new methods for diagnosing infectious diseases and biological weapons.
The researchers utilize a process invented at Northwestern’s Institute for Nanotechnology called Dip-Pen Nanolithography to make arrays of proteins with features more than 1,000 times smaller than those used in conventional arrays. This leads to nanoarrays with more than 1 million times the density of current commercial microarrays.

The process allows researchers to use an atomic force microscope tip as a nano-pen to write out a tiny protein array on a gold surface. With an array of protein “dots” as small as 100 nanometers in diameter, the gold surface in between the dots is processed to prevent it from absorbing target proteins and disturbing the readings. When an array on a chip is exposed to protein targets in solution, the protein on the substrate binds its complementary proteins. The atomic force microscope then reads the chip and records a match where a change in height is detected.

Protein Nanoarrays Generated By Dip-Pen Nanolithography