In Vivo Multiphoton Microscopy for Investigating Biomechanical Properties of Human Skin

Abstract

The biomechanical properties of living cells depend on their molecular building blocks, and are important for maintaining structure and function in cells, the extracellular matrix, and tissues. These biomechanical properties and forces also shape and modify the cellular and extracellular structures under stress. While many studies have investigated the biomechanics of single cells or small populations of cells in culture, or the properties of organs and tissues, few studies have investigated the biomechanics of complex cell populations in vivo. With the use of advanced multiphoton microscopy to visualize in vivo cell populations in human skin, the biomechanical properties are investigated in a depth-dependent manner in the stratum corneum and epidermis using quasi-static mechanical deformations. A 2D elastic registration algorithm was used to analyze the images before and after deformation to determine displacements in different skin layers. In this feasibility study, the images and results from one human subject demonstrate the potential of the technique for revealing differences in elastic properties between the stratum corneum and the rest of the epidermis. This interrogational imaging methodology has the potential to enable a wide range of investigations for understanding how the biomechanical properties of in vivo cell populations influence function in health and disease.

Optical coherence elastography for tissue characterization: a review

“…Elastographic methods based on several optical imaging techniques, including laser speckle imaging [38], multiphoton microscopy [39], confocal Brillouin microscopy [40], and optical coherence tomography (OCT) [41] have been recently developed to meet this demand. Among these, OCT is a three-dimensional imaging modality with micro-scale spatial resolution and millimetre-scale imaging depth in scattering tissues, which enables its clinical applications in many areas, such as ophthalmology and cardiology [42, 43].…”

Determining elastic properties of skin by measuring surface waves from an impulse mechanical stimulus using phase-sensitive optical coherence tomography

“…Recently, this method was further developed into an in vivo three-dimensional OCE imaging system to evaluate normal and hydrated skin [17]. Liang et al [18] employed three-dimensional multi-photon microscopy to detect the biomechanical properties of in vivo human skin at the cellular level. In addition, Grimwood et al [19] presented a technique for generating contrast in two-dimensional shear strain elastograms from a localized stress, by generating a non-uniform, localized stress via a magnetically actuated implant.…”

Quantitative characterization of mechanically indented in vivo human skin in adults and infants using optical coherence tomography

“…[1][2][3]38,39 Optical coherence microscopy (OCM) can be used to detect structural, biomechanical, and hemodynamics of skin at the cellular level. 40,41 Moreover, OCM can be integrated with multiphoton and fluorescence lifetime imaging microscopy to provide molecular contrast, infer cellular metabolism state, and monitor the cell dynamics in skin tissue. 42,43 Visualization of molecular information of skin can also be assessed via nonlinear interferometric vibrational imaging.…”