Nanomechanical Mapping of Skin Dermis

Nanoscale morphology and mechanical properties of the skin dermis were measured by AFM using previously established techniques in our laboratory with minor modifications [15 (link)]. Briefly, OCT embedded human skin samples were sectioned (50 μm) and mounted on glass coverslips (1.2 mm diameter, Fisher Scientific Co., Pittsburgh, PA). These AFM samples were allowed to air dry for at least 24 hours before AFM analysis. Mechanical properties; traction forces, tensile strength, and deformation were determined by Dimension Icon AFM system (Bruker-AXS, Santa Barbara, CA, USA) using PeakForce^TM Quantitative NanoMechanics mode using a silicon AFM probe (PPP-BSI, force constant 0.01–0.5N/m, resonant frequency 12-45kHz, NANOSENSORS™, Switzerland). PeakForce^TM Quantitative Nanomechanical Mapping (QNM^TM) is a new AFM Nano-mechanical and Nano-imaging mode for measuring the Young's modulus of materials with high spatial resolution and surface sensitivity, by probing at the nanoscale. It maps and distinguishes between nanomechanical properties, including modulus and adhesion, while simultaneously imaging sample topography at high resolution. AFM was conducted at the Electron Microbeam Analysis Laboratory (EMAL), University of Michigan College of Engineering, and analyzed using Nanoscope Analysis software (Nanoscope Analysis v120R1sr3, Bruker-AXS, Santa Barbara, CA, USA).