Life Sciences
Nanoscale FTIR spectroscopy for a broad range of biological materials
AFM-IR chemical distribution image of human hair taken at 2824 cm⁻¹, a common absorption band for lipids.
Life sciences research is continually achieving new discoveries due to new nanoscale IR spectroscopy. The nanoIR3 provides unrivalled nanoscale FTIR spectroscopy as well as chemical, structural and mechanical property mapping of a broad range of biological materials. Researchers using AFM-IR have generated groundbreaking conclusions in protein secondary structures that are linked to disease formation. Applications include:
- Cells, proteins, bacteria
- Tissue, bone and hair
- Bio-materials and bio-minerals
- Pharmaceuticals
- Wood and plants samples
- Bio-polymer films
AFM-IR has also excelled in providing nanoscale spectroscopy of tissue, bone, wood, bio-materials, bio-minerals, pharmaceuticals, and many other sample types.
Protein Secondary Structure - Single Fiber
Topographical, chemical, and mechanical analysis of a single collagen fiber, showing amide I absorption. Image courtesy of EPFL, Switzerland.
Protein Structures
AFM-infrared chemical maps and spectra of Josephin proteins before incubation at 37°C. (a) AFM height image. Infrared absorption map at (b) 1700 cm⁻¹ (amide I), (c) 1655 cm⁻¹ (amide I), (d) 1300 cm⁻¹ (amide III). Scale bar, 2mm. (e) Infrared spectra. (f) Average oligomeric infrared spectrum and secondary-structure deconvolution of amide I band. Image courtesy of F.S. Ruggeri et al. DOI: 10.1038/ncomms8831
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Chemical Analysis of Hair
Distribution of Triglycerides in Stratum Corneum
The stratum corneum is the outermost layer of skin and is composed of corneocytes, a dense network of protein, and intercellular lipids. AFM-IR was used to map the distribution of the intercellular lipids of the stratum corneum by imaging the absorption band at 1732 cm⁻¹ in comparison to the amide I absorption band at 1650 cm⁻¹.
Light Harvesting Complex II
Light-harvesting complex II. (a) Surface topography, (b) mechanical stiffness map and (c) IR absorption pattern of the lipoprotein multibilayer, recorded simultaneously on a 1x1 µm area of the sample, the thickness of which was approximately 1.2 µm. Data contributing to the IR-absorption map were acquired at a wavenumber of 1650 cm⁻¹. Scan resolution: X = 512 points, Y = 256 points; scan rate: 0.4 Hz, 8 co-averages.
Purple Membrane
Resonance enhanced AFM-IR was used to collect topographical and AFM-IR images at 1660 cm⁻¹ of Halobacterium salinarium membranes. IR spectra identifies the α-helix structure of the membrane protein by the position of the amide I absorption band.
Self-Assembled Monolayers
AFM imaging, AFM-IR imaging, and Resonance Enhanced AFM-IR spectroscopy of a monolayer island film of a PEG methyl ether thiol on gold.
Biorenewable Polymer
IR spectra of locally heat treated polyhydroxybutyrate (PHB) reveal variations in crystalline/amorphous content (C-O-C stretches, 1270 cm⁻¹).
Bone
AFM-IR spectra reveal variations in the mineral/protein concentration from the interior to the exterior of an osteon.
Pharmaceutical
AFM-IR is used to study phase separation in active pharmaceutical ingredients and passive carrier materials in drug dispersions. The AFM topography image (left) shows phase separation of polyvinylpyrrolidone (PVP) domains in a dextran matrix that are readily identified by the AFM-IR spectra (right).
Wood
Chemical analysis of wood using AFM-IR provides high spatial resolution chemical information of wood composites, preservation treatments, and transgenic wood for biofuels. An AFM topography image (left) of a sectioned wood sample and AFM-IR spectra (right) show variation in the lignin and cellulose ratio between the cell wall and middle lamellae.
Subcelluar Chemical Imaging
Local absorption spectra of a cancer cell where subtle shifts in amide I and II bands (1648, 1536 cm⁻¹) are noted along with its lipid/triglyceride contents (1732 cm⁻¹).
Subcelluar Chemical Imaging
Surface topography (left) of internal structure of streptomyces bacteria. Image of the lipid vesicle distribution via the triglyceride absorption band (center). AFM-IR spectra of the bacteria (blue) and vesicles (black), identifying carbonyl ester bands in both spectra points (right). Scan size: 20 µm x 10 µm. Deniset-Besseau, et al, Chem. Lett., 5 (4) 654–658 (2014).
