Qualitative characterization of collagen hydrogel membranes using digital holographic microscopy and SHG microscopy

Crosslinked collagen hydrogel membranes are widely used in engineering tissue to promote the performance of biological processes involved in the healing of wounds, mainly in the presence of chronical diseases such as diabetes. One of the standard techniques used in biology to measure mechanical properties of hydrogels and tissues is based on a methodology called rheology. Rheological studies consist on the measurement of stress, strain and the ratio of stress to strain of several biological membranes to determine their viscoelastic properties. In this research work we propose as a proof of concept the use of digital holographic microscopy (DHM) and second harmonic generation (SHG) microscopy to compare qualitatively some basic image properties of collagen hydrogel membranes. Once demonstrated that this comparison is equivalent, we study under controlled excitation the biomechanical properties of collagen membranes by means of the analysis of the optical phase that results from comparing two consecutives holograms from a reference and deformed state. At this stage of characterization, an in depth study between rheological and holographic results will be performed in the near future.