The use of digital holographic microscopy for the characterisation of fibrous biomaterials

Developing biomaterials that replicate the body’s complexity while maintaining high functionality is a major challenge. Despite efforts to mimic the extracellular matrix (ECM) chemically and topographically, the biomechanics of fibrous biomaterials remain poorly understood. Electrospun fibrous scaffolds are widely used in biomedical applications, including cell delivery and wound healing, yet their intricate 3D structure complicates micro/nano-scale characterisation. New characterisation tools are urgently needed to accurately assess their biomechanical properties. Digital holographic microscopy (DHM) is a non-invasive, label-free technique that enables high-resolution imaging and real-time analysis of dynamic processes. Here, we present the first application of DHM to characterise the micromechanical deformation of electrospun fibrous membranes. Polycaprolactone (PCL) scaffolds were fabricated via electrospinning, with and without polyethylene glycol (PEG400) as a plasticiser, while spin-coated membranes served as 2D controls. Scanning electron microscopy (SEM) was used for morphological assessment, and a digital holographic microscope (R2100, LYNC´EE) was employed to study micromechanical responses. Our findings demonstrate that DHM provides a powerful new approach for evaluating the micromechanical properties of fibrous scaffolds. This technique offers new insights into the biomechanics of complex biomaterials, paving the way for further studies on cell-material interactions in biomedical applications.