Speaker
Description
Introduction
Light-based biofabrication techniques have revolutionized the field of tissue engineering and regenerative medicine.[1] Specifically, the projection of structured light, where the spatial distribution of light is controlled at both macro- and micro-scale, has enabled precise fabrication of complex three-dimensional structures with high resolution and speed.[2] However, despite ttremendous progress, biofabrication processes have been mostly limited to benchtop devices which limit the flexibility in terms of where the fabrication can occur.[2] Here, we demonstrate a Fiber-assisted Structured Light (FaSt-Light) projection apparatus (Figure 1A), deploying image guide fiber bundles coupled to multiwavelength projection setup for the rapid in situ crosslinking of photoresins. Through in vitro and ex vivo experiments, we demonstrate potential uses cases of the FaSt-Light approach for in situ biofabrication.
Methods
We developed a bespoke multispectral light engine to generate speckled images at 405, 450, 520 nm (Figure 1B), to which the image guide fiber bundles were coupled. For materials, we used gelatin methacryloyl (GelMA) resins with different photoinitiation systems (Norrish Type I and II) suited for each wavelength, which were investigated with the FaSt-Light system on resulting macro- and micro-scale features and potential biofabrication applications.
Results
FaSt Light enabled control over two aspects of the crosslinked resins: 1. Macroscale structures (> 50 µm) imparted through the light engine which controlled the projection image (Figure 1C), and 2. Microscale control, due to optical modulation instability when the laser speckles interact with the photoresin, allowing introduction of cell-guiding microfilaments (2-8 µm, Figure 1C). Through in vitro experiments with myoblasts, we demonstrated that the microfilamented constructs fabricated in situ guided cellular infiltration (Figure 1D), differentiation and anisotropic matrix production resulting in contractile myotubes. Furthermore, the FaSt-Light approach could be used for in vivo printing (Figure 1E) in selected applications for skin wound and muscle defects. Finally, we demonstrated a new scheme which allowed simultaneous multiwavelength image projection, enabling in situ multi-material biofabrication using a resin blend comprising of Collagen I and Polyethylene Glycol Diacrylate (PEGDA) (Figure 1F).
Discussion
Image guide fiber bundles have traditionally been used for capturing images from hard-to-reach regions such as during endoscopy, and to guide images to camera sensors.[3,4] We demonstrated a reverse approach called FaSt-Light, where the fiber bundles allowed projection of images at multiple wavelengths, enabling flexibility on the location of crosslinking. The proposed FaSt-Light approach could lead to a new range of in situ biofabrication techniques which improve the translational potential of photo-fabricated tissues and grafts.
Acknowledgements
P.C. acknowledges funding from Spark grant (CRSK-2_220980) and Ambizione grant (PZ00P2_216356) from the SNSF. M.Z.W. acknowledges funding from European Union call HORIZON-HLTH-2024-TOOL-11-02 (acronym: LUMINATE, number: 101191804) and from Swiss State Secretariat for Education, Research, and Innovation (contract no. 24.00544).
References
[1] Lee, R. Rizzo, F. Surman, M. Zenobi-Wong, Chem Rev 2020, 120, 10950.
[2] R. Levato, K. S. Lim, Biofabrication 2023, 15, 020401.
[3] D. Kim, J. Moon, M. Kim, T. D. Yang, J. Kim, E. Chung, W. Choi, Opt Lett 2014, 39, 1921.
[4] T. M. Peters, C. A. Linte, Med Image Anal 2016, 33, 56.
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