Random Laser Emission Spectra of the Normal and Cancerous Thyroid Tissues

Abstract

In this work, the random laser is investigated as a diagnostic method to distinguish between normal and cancerous Rd6Ginfiltrated in vitro human thyroid tissues. The inherent disorder of the tissues provides the necessary condition for the formation of a number of microresonators providing field feedback for lasing. The longer light path random walk inside a scattering media leads to the stronger reabsorption events. Accordingly, a notable redshift of the LIF emission is observed in the random laser spectra of the cancerous tissues against normal ones. The Fourier transform and power Fourier transform of random laser spectra collected from many excitation locations in the tissue give rise to the rapid identification of normal and malignant tissues. Moreover, the mean sizes of the randomly formed microresonators are estimated to be ~ 20 μm, comparable to the average size of the typical thyroid cell.

Properties and Applications of Random Lasers as Emerging Light Sources and Optical Sensors: A Review

“…Several RL spectral properties such as the lasing modes [ 30 ], threshold [ 32 ] and peak shift [ 31 ] were employed to distinguish between healthy and cancerous tissues. Polson et al [ 30 ] reported RLs from R6G-infiltrated human colon tissues.…”

“…This is probably because there are more disorders in malignant grade III tissues. In addition, a wavelength shift can also be applied for cancer diagnosis [ 31 ]. The cancerous thyroid tissues always induce a peak wavelength at the longer-wavelength side compared to the healthy thyroid tissues at the same pumping energy, as shown in Figure 10 c. The author argued that light dwells longer due to more disorders in the cancerous tissues, resulting in a stronger reabsorption and re-emission effect, which causes a stronger peak wavelength redshift.…”

“…The multiple scattering can currently be obtained from various media, such as polymers [ 6 , 7 ], crystalline materials [ 8 , 9 ], semiconductor materials [ 10 , 11 ], scattering micro-/nano-particles [ 12 , 13 ] or a combination of the above scattering systems [ 14 , 15 , 16 ]. In addition, RLs have been achieved in biological materials such as abalone shell [ 17 ], silk [ 18 ], eggshell membranes [ 19 ], leaves [ 20 , 21 ], wings of butterfly/moth/cicada [ 22 , 23 , 24 ], animal tissues (chicken breast [ 25 ], cortical bone [ 26 ], pig head [ 27 ], mouse brain [ 28 ], mouse uterine [ 29 ]) and human tissues (colon [ 30 ], thyroid [ 31 ] and breast [ 32 , 33 , 34 ]). Light can undergo scattering because of the presence of the dielectric constant variations in the above various complex systems.…”

“…Variations in scatterer concentrations [ 52 , 53 , 54 ], gain media [ 53 ] and refractive indices of solvent [ 55 , 56 ] have been detected through the RL emission. Sensing applications have been extended to the biological field, such as the optomechanical and bio-chemical sensing (nanoscale mechanical sensing in hard [ 26 ] and soft [ 57 ] tissues, dopamine sensing [ 58 ], PH sensing [ 59 ] and human antibody IgG sensing [ 60 ]), tissue differentiation [ 27 ], cell differentiation [ 28 , 61 ], cancer diagnosis [ 30 , 31 , 32 ] and cancer therapy [ 29 , 33 ]. A sensing scale of RLs down to the cell level has recently attracted an increasing interest [ 34 , 51 , 62 ].…”

Random Lasing for Bimodal Imaging and Detection of Tumor

“…In 2004, Polson et al pioneered the demonstration of random lasing emission in biological tissues and, since then, it has been realized in various biological tissues including human organs, such as the brain, breast, thyroid, etc. [3,[7][8][9][10]. Being highly sensitive to disorder, random lasing has been demonstrated to be useful in detecting even nanoscale structural changes and deformations in bones [11].…”