In vitro effects on cellular shaping, contratility, 1 cytoskeletal organization and mitochondrial activity 2 in HL1 cells after different sounds stimulation. A 3 qualitative pilot study and a theoretical physical 4 model.
6Abstract: Convincing evidence has documented that mechanical vibrations profoundly affect the 24 behaviour of different cell types and even the functions of different organs. Pressure waves such as 25 those of sound could affect cytoskeletal molecules with coherent changes in their spatial 26 organization and are conveyed to cellular nucleus via mechanotransduction. HL1 cells were grown 27 and exposed to different sounds. Subsequently, cells were stained for phalloidin, beta-actin, 28 alpha-tubulin, alpha-actinin-1 and MitoTracker ® mitochondrial probe. The cells were analyzed with 29 time-lapse and immunofluorescence/confocal microscopy. In this paper, we describe that different 30 sound stimuli seem to influence the growth or death of HL1 cells, resulting in a different 31 mitochondrial localization and expression of cytoskeletal proteins. Since the cellular behaviour 32 seems to correlate with the meaning of the sound used, we speculate that it can be "understood" by 33 the cells by virtue of the different sound waves geometric properties that we have photographed and 34 filmed. A theoretical physical model is proposed to explain our preliminary results. 35 36 37 Time-lapse microscopy.38 39 40 41 42 48resonances, i.e. the synchronization of the biomolecular oscillatory patterns within cells [14] .
49For example, it has been shown that bacterial cells are able to respond to specific single acoustic 50 frequencies and are able to emit sounds [15] .
51Moreover, it has been demonstrated that acoustic vibrations in the form of single frequencies [16] , 52 noise or music, alter proliferation, viability [17] and hormone binding [18] in human cells cultures and 53 in animal models [19,20], [21] . 54 Ventura et al. have recently reported that human stem cells seem to respond to complex sound 55 frequencies (melodic music, rhythm patterns and human voice) with different electromagnetic 56 emissions measured with a Multi Spectral Imaging system [22] .
57Furthermore, acoustic stimuli seem to be of paramount importance in guiding the spatial 58 interaction between cells, thus influencing their individual and collective behavior [23], [24] .
59It is very probable that all this evidence transmits, at a macroscopic level, the phenomena of 60 cellular mechanotransduction, a discipline that focuses on how extracellular physical forces are 61 converted into chemical signals at the cell surface. However, mechanical forces that are exerted on 62 surface-adhesion receptors, such as integrins and cadherins, are also channeled very rapidly along 63 cytoskeletal filaments and concentrated at distant sites in the cytoplasm and nucleus [9,25,26] , altering 64 cellular genome activities [27] .
65All the research conducted so far has mostly explored the possible biological effects of 66 ultrasound or audible ac...
