(continued)

In "Fish gelatin combined with chitosan coating inhibits myofibril degradation of golden pomfret (Trachinotus blochii) fillet during cold storage," (1) researchers Feng, Bansal, & Yang extracted myofibril, the major component of fillet muscle, from fish samples and analysed samples with the TT-AFM. Imaging and quantitative analysis demonstrated how myofibril degraded during cold storage. The researchers used AFM data to suggest the mechanisms for the protective effects of chitosan coatings, a natural polysaccharide obtained from the de-acetylation of chitin in shrimp and other crustacean shells.

In "Layer-by-layer films containing peptides of the Cry1Ab16 toxin from Bacillus thuringiensis for potential biotechnological applications," (2) researchers Plácido et al., studied Cry1Ab16, an insecticidal toxin (crystalline protein) that has been widely used in genetically modified organisms (GMOs) to gain resistance to pests.

The group immobilized PcL342-354C, a peptide derived from the immunogenic toxin, as layer-by-layer (LbL) films onto ITO. The TT-AFM was used to examine the morphology and to quantify the surface roughness of the films produced.  The AFM results showed that the adsorbed peptide formed self-assembled nanofibers with diameters ranging from 100 to 200 nm on the polymeric film and very homogeneously distributed. The LbL films were smoother than the substrate, however, there was no difference between the surface
roughness of the films with multiple layers.

In "Superhydrophobic nanofiber membrane containing carbon nanotubes for high-performance direct contact membrane distillation", (3) researchers Tijing et al., used the TT-AFM to characterize the topography and roughness of fabricated superhydrophic nanofiber membranes containing carbon nanotubes (CNTs). The researchers confirmed that the overlappping structure of the nanofibers created hills and valleys that produce rough surfaces, and that incorporating CNTs in the nanofibers provided additional roughness, favoring hydrophobicity.

Whether an atomic force microscope (AFM) cost $30,000 or $300,000, the validity and quality of its research results and images depends less on the equipment's bells and whistles than it does on the skills and procedure of the operator and environment. For more on the essentials of AFM procedure, you may want to review articles throughout the AFMWorkshop website, including for example Four Criteria for Measuring Great AFM images, or watch one of several brief but informative AFMWorkshop training videos that include successful sample preparation, recognizing artifacts in AFM images, proper probe selection, and more.

 

DNA and Graphene measured with TT-AFMChallenging samples don't necessarily require expensive AFMs. Left, a 1 µm x 1 µm AFM image of DNA; Right, 11 µm x 11 µm AFM image of graphene. Both are measured by a $30,000 TT-AFM.

1. X. Feng, N. Bansal and H. Yang (2016). "Fish gelatin combined with chitosan coating inhibits myofibril degradation of golden pomfret (Trachinotus blochii) fillet during cold storage." Food Chemistry 200:283-292.

2. A. Plácido, E.A. de Oliveira Farias, M.M. Marani, A.G. Vasconcelos, A.C. Mafud, Y.P. Mascarenhas, C. Eiras, J.R.S.A. Leite and C. Delerue-Matos (2016). "Layer-by-layer films containing peptides of the Cry1Ab16 toxin from Bacillus thuringiensis for potential biotechnological applications." Materials Science and Engineering: C, 61: 832-841.

3. L.D. Tijing, Y.C. Woo, w.-G. Shim, T. He, J.-S. Choi, S.-H. Kim and H. K. Shon (2016). "Superhydrophobic nanofiber membrane containing carbon nanotubes for high-performance direct contact membrane distillation." Journal of Membrane Science 502: 158-170.

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