Poster Presentation 24th Australian Conference on Microscopy and Microanalysis 2016

Nano/micro scale characterization of tissue specimens with atomic force microscopy (#232)

Yeonuk Kim 1 , Jiachun Huang 1 , Aswan Al-Abboodi 1 , Catriona McLean 2 , Jing Fu 1
  1. Department of Mechanical and Aerospace Engineering, Monash University, CLAYTON, VIC, Australia
  2. Anotmical Pathology, Alfred Hospital, Prahran, VIC, Australia

With high precision characterization capability of Atomic Force Microscopy (AFM), we investigate the surface properties of both engineered and native tissue specimens including hydrogel and surgically retrieved tissues. Hydrogel is known for its biocompatibility and its physical and chemical properties suitable for cell growth and proliferation 1 2. Recently it has been also revealed that initiation and progression of cancer are associated with molecular and structural changes in extracellular matrix which produce distinct mechanical responses 3 4. As such, high resolution and effective characterization approaches are highly sought for the tissue specimens.

In our study, thin film of hydrogel was prepared by spin coating on a silicon wafer 5 and sections of human tissue specimens from surgical procedures were prepared with a microtome after fixation. Surface properties such as surface morphology were investigated using preliminary Scanning Electron Microscopy (SEM) imaging followed by AFM studies on both surface topology and mechanical moduli. Results showed that nano and micro scale features on tissues can be revealed in both ambient and hydrated environments. Tuned modulus and damages on the hydrogel were measurable, which remain challenges for other approaches. For the pathological tissue specimens, stiffness patterns acquired by AFM allowed identifying regions of varied cell types, e.g., the measured stiffness of fibrous cells was shown to be significantly higher than those of epithelium and lymphoid cells. The cell recognition results after statistical evaluations are consistent with the visual inspection results from pathologists. With chemically fictionalized AFM cantilevers, chemical signatures of tissue specimens were also explored, and results showed that distinct adhesion patterns were detected from different cell types. We expect that with the capability of acquiring multiple surface properties from tissue specimens, AFM will contribute as a unique imaging technique for tissues, and also can function as a novel diagnostic tool in the future.

  1. 1. Gaston, A., et al., Nanopatterned UV curable hydrogels for biomedical applications. Microelectronic Engineering, 2010. 87(5-8): p. 1057-1061.
  2. 2. Al-Abboodi, A., et al., Three-dimensional nanocharacterization of porous hydrogel with ion and electron beams.
  3. 3. Plodinec, M., et al., The nanomechanical signature of breast cancer. Nat Nano, 2012. 7(11): p. 757-765.
  4. 4. Butcher, D.T., T. Alliston, and V.M. Weaver, A tense situation: forcing tumour progression. Nat Rev Cancer, 2009. 9(2): p. 108-122.
  5. 5. Kim, Y., et al., Tuning the surface properties of hydrogel at the nanoscale with focused ion irradiation. Soft Matter, 2014. 10(42): p. 8448-8456.