The Power of CAD/CAM Laser Bioprinting at the Single-Cell Level: Evolution of Printing

Laser Direct Write Bioprinting Enriched Cell Types in the Breast Tumor Microenvironment

“…Minimizing shear stress on the stress during droplet ejection and landing combined with preventing UV-C phototoxicity ensures that matrix assisted pulsed laser evaporation bioprinting is extremely gentle on the cells and results in high post-printing cell viability. [2] [3]…”

“…Compared to conventional bioprinting techniques, laser direct write bioprinting, also known as matrix-assisted pulsed laser evaporation bioprinting, has the unique ability of mimicking the complexity of human tissue at the cellular scale, thereby giving us the control to pattern cells at high resolution, and to control cell-cell interaction and potentially "build" a tissue piece-by-piece rather than simply growing it [1] . It has further advantages in terms of automation, reproducibility and high throughput [2] [3] [4] [5] [6] [7].…”

“…Although initially, Matrigel was used as the ribbon matrix, gelatin has been demonstrated to be a cheaper and more effective alternative [4] [8] [9]. The gelatin layer acts as an absorption medium which not only results in forward transfer of cell-laden droplets but also protects cells from the adverse effects of laser radiation as it facilitates the conversion of electromagnetic energy to mechanical energy [2]. According to the Beer-Lambert law, the penetration depth of UV-C radiation in a sufficiently concentrated hydrogel is <<10 um as UV-C radiation is primarily absorbed by macromolecules [10] and the laser radiation never comes into direct contact with the cells.…”

“…To build physiologically relevant in vitro models of the breast tumor microenvironment and recapitulate metastatic cell dynamics, it is not only important to incorporate multiple cell types but also pattern them in appropriate geometries to facilitate cell-cell interactions. Laser direct write bioprinting is a high resolution, reproducible cell printing technique that could serve as a valuable tool to fabricate heterocellular breast tumor microenvironments in vitro as it is a cell type independent technique conducive to viably patterning cells with high densities to facilitate juxtacrine signaling [2] [3]. Herein, we developed laser direct write based cell printing methods to print heterocellular arrays of human triple negative breast cancer cells and human fibroblasts with both homotypic and heterotypic spots.…”

“…Most tissue engineering and bioprinting techniques, however, tend to neglect including the immune component, presumably because human immune cells can be challenging to work with in vitro [19]. Laser direct write bioprinting is a precise, gentle and customizable cell printing technique conducive to printing a variety of cell types [2] [3]. Thus, we also made various adaptations to the aforementioned generalized methodology to develop a novel protocol to viably bioprint human macrophages with high fidelity.…”