Understanding How Cells Sense and Respond to Mechanical Stimuli

JPK Instruments reports on the work of Professor Marco De Spirito's research group at the Catholic University of Rome. The group uses a NanoWizard® AFM and CellHesion® module to study how cells sense and respond to mechanical stimuli. 

Dr Gabriele Ciasca and Professor Massimiliano Papi are members of the research team of Professor Marco De Spirito in the Institute of Physics at the Catholic University of Rome, Italy. One of the main goals of their group is the investigation of how cells sense and respond to physical and mechanical stimuli. Professor De Spirito says that a deeper knowledge of cell biomechanics can boost the understanding of how mechanical properties affect and are affected by the development of many pathological states including cancer. 

An example of this research has been reported in a recent clinical paper published in the high impact factor journal Nanoscale. This paper, “Nano-mechanical signature of brain tumours,” was carried out in collaboration with Dr Tanya Enny Sassun during her PhD in the group of Professor Delfini, head of the Department of Neurology and Psychiatry, Neurosurgery (Sapienza University of Rome). The research group studied the biomechanical fingerprint of the two most frequent malignant and benign brain tumours: the highly aggressive Glioblastoma and the slowly-growing Meningioma. They investigated the complex biophysical interplay between neoplastic cells and the tumour microenvironment using the NanoWizard® AFM from JPK. This showed that AFM is able to easily distinguish between cancerous and healthy peritumoural tissues. 

Eleonora Minelli - who works as a PhD student in the group of Professor De Spirito - takes up the story of how this work has been extended. “The acquisition of elasticity maps of surgically removed tissues is plagued by the problem of roughness that is often larger than the available range of the piezoelectric actuator. This meant we have had to develop a novel procedure that allowed us to acquire elasticity maps of an unparalleled size (up to 100 µm x 100 µm). We achieved this result thanks to the use of the JPK CellHesion® module that can be easily integrated to our NanoWizard®. This has a z-piezoelectric actuator with a range of 100 µm. These results open up many applications in nanomedicine and have the potential to boost the use of AFM in clinical practice. AFM, together with confocal microscopy and electron microscopy, are key tools in this research area because it allows us to probe mechanical and topographical properties of molecules, cells and tissues in nearly all environments.” 

Dr Ciasca, Professor Papi and their colleagues have a lot of experience using different makes of AFM. “The members of our group have been working with many general-purpose AFM set-ups. Now, we are deeply convinced that the JPK NanoWizard® offers one of the best suited experimental set-ups for the investigation of biological systems. There are a number of reasons for this. The instrument has an easy, accurate and effective cantilever calibration procedure. We believe this is a key advantage of this platform as it ensures reproducibility and reliability of results. This is particularly important when dealing with the nanoscale mechanical properties of cells and tissues that are intrinsically subjected to a large biological variability. The geometry of the scanning head is a unique characteristic of the JPK NanoWizard®. It opens the possibility to investigate cells and tissues directly within conventional petri dishes in a liquid environment. This key characteristic allowed us to investigate the mechanical and structural properties of living cells in their own environment without the need of fixation procedures that deeply alter mechanical and morphological properties. Most importantly, the NanoWizard® in our laboratory offers effective integration with a conventional inverted fluorescence microscopy which allows us to combine fluorescence and optical images with elasticity maps.”