Granular Bioink Made-To-Order from Macroporous Collagen Particles Offers Excellent Printability, Shape Fidelity, and Reduced Tissue Contraction

我们的提案专注于增强完整生物打印解决方案的价值主张，该解决方案将皮肤前体片材直接合成并递送到大的皮肤伤口表面上（即，原位），在那里它们可以作为伤口敷料，促进愈合并减少疤痕和伤口挛缩（这会破坏外形并限制人的运动）。我们的解决方案包括三个组成部分：一个手持式生物打印机仪器，其开发已经完成，而不是提案的一部分，一种新的定制生物墨水，可以容纳活细胞，以及生物打印机的一次性部件，包括多喷嘴打印头，它将生物墨水直接挤出到目标表面上。我们新定制的生物墨水由紧密堆积的胶原蛋白颗粒组成。我们将优化生物墨水的“可印刷性”，这一特性将使生物墨水能够在人体上发现的各种表面拓扑结构上形成毫米厚的皮肤前体片。我们将进一步优化多喷嘴打印头的设计，使其能够挤出均匀尺寸和成分的片材，同时最大限度地提高生物墨水中细胞的活力，并最大限度地减少片材合成和交付所需的时间。

Our proposal is focused on enhancing the value proposition of a complete bioprinting solution that synthesizes and delivers skin precursor sheets directly onto the surface of large skin wounds (i.e., in situ), where they can act as wound dressings that promote healing and reduce scarring and wound contracture (which disfigures and limits a person's movement). Our solution includes three components: a handheld bioprinter instrument whose development is already complete and not part of the proposal, a new customized bioink that can harbour living cells, and disposable parts of the bioprinter, including multi-nozzle printheads, which extrude bioink directly onto the target surface. Our new customized bioink consists of tightly packed granules of collagen. We will optimize the bioink's "printability", a feature that will enable the bioink to form mm-thick skin precursor sheets on the wide range of surface topologies found on the human body. We will further optimize the design of the multi-nozzle printheads enabling it to extrude sheets of uniform size and composition, while maximizing the viability of cells in the bioink and minimizing time needed for sheet synthesis and delivery.