LENSFREE DIFFRACTIVE TOMOGRAPHY FOR THE IMAGING OF 3D CELL CULTURES CONTACT : Anthony Berdeu [email protected] A. Berdeu1,2, F. Momey1,2, N. Picollet-D’Hahan1,3,4, S. Porte1,3,4, X. Gidrol1,3,4, T. Bordy1,2, J.M. Dinten1,2, C.Allier1,2 Context Apply lensfree microscopy to 3D cell culture Lack of non-invasive imaging Difficult to get acquisitions of large volumes Rise of lensfree imaging for 2D cell cultures Experimental prototype (first data on biological culture) Proof of concept (first algorithms for 3D reconstruction) Operational device Cheap, robust and easy to implement Label free and time lapse microscopy Robust to incubator Suited to living samples Setup: lensfree in-line holography 𝑈𝑖𝑛𝑐 𝑈𝑑𝑖𝑓 𝑧 𝑈𝑑𝑖𝑓 2𝜋𝑛0 𝑘0 = 𝜆 𝑛0 the medium refraction index 𝐹 𝑟 ′ . 𝑈𝑖𝑛𝑐 𝑟 ′ . 𝑒 𝑂𝑏𝑗𝑒𝑐𝑡 𝐹 𝑟 = −𝑘02 𝑛 𝑟 𝑛0 𝑖𝑘0 𝑟′ 𝑦 𝑈𝑡𝑜𝑡 = 𝑈𝑖𝑛𝑐 + 𝑈𝑑𝑖𝑓 rotation axis for 𝜽 𝑥 𝑖𝑘0 𝑟 ′ with 𝑧 𝑒 𝑈𝑖𝑛𝑐 = 𝑒 𝑖𝑘0 .𝑟 and ℎ𝑧,𝑘0 = . 𝑖𝜆 𝑈𝑑𝑖𝑓 = 𝛿𝑡 ⋆ ℎ𝑧,𝑘0 𝑟′ 2 𝒇 𝑧 𝑟 𝑟 ′ −𝑟 −𝑟 ∝ Object modelled by a 2D transmission plane: 𝑡2𝐷 = 1 + 𝛿𝑡 𝑗 𝑘03 𝑦 𝑂 𝑥 𝑗 𝑗 𝑗 𝑝02 , 𝑞02 , 𝑚02 𝑗 𝑘01 𝑟′ 𝑈𝑡𝑜𝑡 = 𝑈𝑖𝑛𝑐 + 𝑈𝑑𝑖𝑓 1 𝑟 =− 4𝜋 𝑗 𝑘02 𝜃 𝐹 scattering potential Digital sensor - 1,67 𝜇𝑚 3840 × 2748 pixels Phase retrieval 3D Fourier mapping Acquisition Semi-coherent illumination (about angle 𝜑 // 𝜃 = 45°) Processing 𝑑3 𝑟 ′ 2 −1 2 𝑈𝑑𝑖𝑓 𝑗 3 𝑈𝑑𝑖𝑓 𝑦 𝑥 𝑈𝑡𝑜𝑡 2 ⋆ ℎ−𝑧,−𝑘0 data Lack of phase in the data: 𝑣 𝑢 Simple back propagation Introduction of a phase ramp to take into account the tilted wavefront Twin-image in the data inversion Solution: inverse problem 3D spatial 3D frequency −1 domain ℱ3𝐷 domain Acquisitions & results 𝑗 𝑗 1 𝑈𝑑𝑖𝑓 2D frequency 2D Spatial Mapping domain ℱ2𝐷 domain φ 𝜃 Grenoble Alpes, F-38000 Grenoble, France, 2CEA, LETI, MINATEC Campus, F-38054 Grenoble, France, 3CEA, BIG – Biologie à Grande Echelle, F-38054 Grenoble, France, 4INSERM, U1038, F-38054 Grenoble, France Objectives Growth of 3D cell culture in organic gel 1Univ. 𝑙1 -norm minimization: sparse objects 𝑇𝑉 minimization: sparse gradient ℜ 𝛿𝑡 < 0: non-emissive objects 𝛽 spherical caps 𝛼 data fidelity 𝑭 𝛾 𝛿𝑡0 = min 𝛿𝑡 ℜ 𝛿𝑙 <0 𝐼𝑑𝑎𝑡𝑎 − 𝑈𝑖𝑛𝑐 + 𝛿𝑡 ⋆ ℎ𝑧,𝑘0 +𝜇𝐿1 𝛿𝑡 𝑦 𝐿1 + 𝜇 𝑇𝑉 𝛻 𝛿𝑡 2 2 … 𝐿1 Residual artifacts (twin image, …) 𝑥 𝑧 𝑗 𝐹 𝛼 𝑗 , 𝛽 𝑗 , 𝛾 𝑗 = 4𝑖𝜋𝑤. 𝑒 −2𝑖𝜋𝑤𝑧𝑠 𝑈𝑑𝑖𝑓 𝑢, 𝑣; 𝑧𝑠 Matrigel® capsules data 𝜑 = 0°, 84.6°, 169.2° The arrows point on special features 𝜆 = 630 𝑛𝑚 𝑗 𝑗 𝑗 with 𝛼 , 𝛽 , 𝛾 𝑗 𝑗 𝑗 𝑛0 𝑝0 𝑛0 𝑞0 𝑛0 𝑝0 = 𝑢− ,𝑣 − ,𝑤 − 𝜆0 𝜆0 𝜆0 and 𝑤 = 𝑛02 − 𝑢2 − 𝑣 2 𝜆20 Retrieved phase 𝑡2𝐷 = 1 + 𝛿𝑡0 Conclusions Working prototype with 3D biological samples acquisitions 2D slantwise phase retrieval on real data acquisitions First 3D reconstructions on several 𝒎𝒎𝟑 volumes Perspectives Incubator-proof prototype for 3𝐷 + 𝑡 acquisitions Reconstruction of 5123 × 3.343 𝜇𝑚3 = 5𝑚𝑚3 volumes without/with phase retrieval on the 2D dataset. 31 angles 𝜑 = 0°: 9.4°: 282° , 𝜃 = 45°. Cell-sized beads can be resolved both on 𝑥𝑦-plane and 𝑧-axis. References [1] Momey F. & al., Lensfree diffractive tomography for the imaging of 3D cell cultures, Biomed. Opt. Express 7, 949-962 (2016) [2] Dolega, M.E. & al. Label-free analysis of prostate acini-like 3D structures by lensfree imaging. Biosensor and Bioelectronics, 49, 176-183, 2013. [3] Kesavan S. V. & al., Highthroughput monitoring of major cell functions by means of lensfree video microscopy. Nature Scientific Reports, 4, n°5942, 2014. [4] Gabor D., A new microscopic principle. Nature, 161, 777-778, 1948. [5] Wolf E., Three-Dimensional structure determination of semitransparent objects from holographic data. Optics communications, vol. 1, n°14, pp. 153-156, 1969. [6] Kak, A., Slaney, M. Principles of computerized tomographic imaging. IEEE Press, 1988. [7] Sung, Y. Optical, diffraction tomography for high resolution live cell imaging. Optics express, vol. 17, n°11, pp. 266-277, 2009. [8] Haeberlé, O. & al., Tomographic diffractive microscopy : basics, techniques and perspectives. Journal of Modern Optics, 2010. Improve data alignment Inverse problem algorithms on the 3D volume [9] Isikman S. O. & al., Lens-free optical tomographic microscope with a large imaging volume on a chip, Proc. Natl. Acad. Sci. U.S.A. 108(18), 7296-7301. (2011). [10] Rudin, L.I. & al., Nonlinear total variation based noise removal algorithms. Journal of Modern Optics, 2010. Journée de l’école doctorale EDISCE Grenoble – Faculté de pharmacie – 6 Juin 2016