Infrared microspectroscopy combined with conventional atomic force microscopy.

Area of Science:

• Materials Science
• Spectroscopy
• Microscopy

Background:

• Atomic Force Microscopy (AFM) excels at high-resolution topographical imaging.
• Mid-infrared (IR) microspectroscopy provides chemical information but often lacks topographical detail.
• Integrating these techniques offers synergistic analytical capabilities.

Purpose of the Study:

• To develop and demonstrate a novel method combining mid-IR microspectroscopic imaging with AFM nanotopography.
• To utilize a standard AFM cantilever as a detector for IR light.
• To enable simultaneous acquisition of topographical and chemical information from samples.

Main Methods:

• A bimaterial microcantilever, typically used for AFM, was employed as a detector for monochromatic IR light.
• IR light intensity was measured via thermomechanical bending of the cantilever upon modulated IR illumination.
• The cantilever bending was correlated with the sample's IR absorption, achieving spatial resolution of 24.4 μm.

Main Results:

• Successful integration of mid-IR microspectroscopy and AFM nanotopography within a single instrument.
• Demonstrated spatial resolution of AFM topography at the nanometer scale.
• Achieved IR spatial resolution of 24.4 μm with spectral resolution of 25-125 cm⁻¹.
• Mapped engineered skin and 3D cell cultures, showcasing the method's applicability.

Conclusions:

• The developed technique offers a facile approach to combine AFM's topographical imaging with IR chemical analysis.
• This integrated method provides complementary information, enhancing sample characterization.
• The approach holds potential for analyzing complex biological and engineered materials.