High resolution imaging of TGFβ3 treated human keratinocyte via a newly developedwidefield surface plasmon resonance microscope

In this study high resolution imaging of human adult (HaCaTs) Keratinocytes cells using the newly developed Widefield Surface Plasmon Resonance (WSPR) system will be discussed. Surface Plasmon Resonance (SPR) occurs at the interface between a dielectric and a thin conducting layer when p-polarized light strikes at a specific angle thus excites free electrons and generates surface plasmon electromagnetic wave. The SPR excitation angle can be changed by the binding of bio-molecular species to the metallised layer, and is directly proportional to the refractive index and thickness of that molecular species. Our WSPR system provide high lateral resolution imaging close to 500 nanometers [1] and was used to investigate cell surface interactions under two different culture conditions: HaCaTs cultured on SPR substrate with Transforming Growth Factor β3 (TGFβ3) (50ng/ml) [2] and without TGFβ3. In less than 24 hours, HaCaTs cultured in the presence of TGFβ3 showed enhanced division and motility along with decreased cell attachment as compared with cells maintained in TGFβ3 free media. It is to be noted that cellular signaling by TGFβ3 is very important for enhancing tissue development in wound repair and that this study for the first time enabled optical interrogation of cell surface interface without the need for Immunostaining.