title: Measurement of diabetic wounds with optical coherence tomography-based air-jet indentation system and a material testing system.
abstract: OBJECTIVE
  Material testing system is a conventional but destructive method for measuring the biomechanical properties of wound tissues in basic research. The recently developed optical coherence tomography-based air-jet indentation system is a non-destructive method for measuring these properties of soft tissues in a non-contact manner. The aim of the study was to examine the correlation between the biomechanical properties of wound tissues measured by the two systems.
  
  
  METHODS
  Young male Sprague-Dawley rats with streptozotocin-induced diabetic were wounded by a 6 mm biopsy punch on their hind limbs. The biomechanical properties of wound tissues were assessed with the two systems on post-wounding days 3, 7, 10, 14, and 21. Wound sections were stained with picro-sirius red for analysis on the collagen fibres. Data obtained on the different days were charted to obtain the change in biomechanical properties across the time points, and then pooled to examine the correlation between measurements made by the two devices. Qualitative analysis to determine any correlation between indentation stiffness measured by the air-jet indentation system and the orientation of collagen fibres.
  
  
  RESULTS
  The indentation stiffness is significantly negatively correlated to the maximum load, maximum tensile stress, and Young's modulus by the material testing system (all p<0.05). The orientation of collagen changes with the indentation stiffness over time.
  
  
  CONCLUSIONS
  Our findings support the use of optical coherence tomography-based air-jet indentation system to evaluate the biomechanical properties of wounds in a non-contact manner. It is a potential clinical device to examine the biomechanical properties of chronic wounds in vivo in a repeatable manner.
authors.affiliation: Department of Rehabilitation Sciences, The Hong Kong Polytechnic University, Hong Kong SAR, China.
authors.forename: M-C
authors.initials: MC
authors.lastname: Choi
authors.affiliation: Department of Rehabilitation Sciences, The Hong Kong Polytechnic University, Hong Kong SAR, China.
authors.forename: K-K
authors.initials: KK
authors.lastname: Cheung
authors.affiliation: Department of Rehabilitation Sciences, The Hong Kong Polytechnic University, Hong Kong SAR, China.
authors.forename: G Y-F
authors.initials: GY
authors.lastname: Ng
authors.affiliation: Interdisciplinary Division of Biomedical Engineering, The Hong Kong Polytechnic University, Hong Kong SAR, China.
authors.forename: Y-P
authors.initials: YP
authors.lastname: Zheng
authors.affiliation: Department of Rehabilitation Sciences, The Hong Kong Polytechnic University, Hong Kong SAR, China.
authors.forename: G L-Y
authors.initials: GL
authors.lastname: Cheing
mesh_terms: D000388:Air; D000818:Animals; D001696:Biomechanical Phenomena; D003921:Diabetes Mellitus, Experimental; D006614:Hindlimb / Q000293:injuries*; D008297:Male; D008422:Materials Testing / Q000379:methods; D051381:Rats; D017207:Rats, Sprague-Dawley; D012883:Skin Ulcer / Q000451:nursing / Q000473:pathology* / Q000517:prevention & control; D041623:Tomography, Optical Coherence; D014945:Wound Healing
keywords: OCT-based air-jet indentation system; biomechanical properties; diabetic wound; rat model