A team of scientists from the National Taiwan University, the Technical Universities of Denmark and Munich, and the Physikalisch-Technische Bundesanstalt has built an open source design for a nanoscale imaging high-speed atomic force microscope (HS-AFM) — buildable for under $4,000.
"For the first time," says co-author Edwin Hwu of the team's work, "you can build a High-Speed AFM and get 46x46µm, 512x512 pixels image in 9.3 seconds. [This] low-cost HS-AFM can measure the nanotexture of human skin corneocytes. Costs you less than a Mac Pro!"
Building on an earlier design, Hwu and colleague's controller design offers a doubling of imaging area and a hundredfold boost to its scanning velocity — providing the performance required for practical use. To prove it, the team used the tool to assess the severity of atopic dermatitis (AD) in human subjects — measuring the nanotexture of corneocytes, or "horny cells," the size of which provides an indication of the regenerative capacity of the skin.
An atomic force microscope works through contact: An ultra-fine needle is run across the surface of the object to be imaged, physically feeling its dimensions and reporting the result back to the host system for processing into a visible image. Typically, such devices are extremely expensive — but the version built by Hwu and colleagues comes in at $3,936 in parts. Better yet, it is released under an open-hardware license for all to replicate.
The team's controller uses a National Instruments myRIO-1900 FPGA development board connected to the Arduino-based Strømlingo DIY AFM, a simplified atomic force microscope design, and generates fast-axis and slow-axis scanning — upgrading the Strømlingo to high-speed operation.
"We believe that in addition to working on simplified AFMs," the team writes in conclusion, "[this] open source controller can upgrade old AFMs to have high-speed DC mode measurements, thereby further expanding the HS-AFM research community."
The team's work is published under open-access terms in the journal HardwareX, with design files and source code available under the Creative Commons Attribution 4.0 International license on OSF Home.