An open-source handheld extruder loaded with pore-forming bioink for in situ wound dressing

Abstract

The increasing demand in rapid wound dressing and healing has promoted the development of intraoperative strategies, such as intraoperative bioprinting, which allows deposition of bioinks directly at the injury sites to conform to their specific shapes and structures. Although successes have been achieved to varying degrees, either the instrumentation remains complex and high-cost or the bioink is insufficient for desired cellular activities. Here, we report the development of a cost-effective, open-source handheld bioprinter featuring an ergonomic design, which was entirely portable powered by a battery pack. We further integrated an aqueous two-phase emulsion bioink based on gelatin methacryloyl with the handheld system, enabling convenient shape-controlled in situ bioprinting. The unique pore-forming property of the emulsion bioink facilitated liquid and oxygen transport as well as cellular proliferation and spreading, with an additional ability of good elasticity to withstand repeated mechanical compressions. These advantages of our pore-forming bioink-loaded handheld bioprinter are believed to pave a new avenue for effective wound dressing potentially in a personalized manner down the future.

High-resolution lithographic biofabrication of hydrogels with complex microchannels from low-temperature-soluble gelatin bioresins

“…As a final step for the characterization of the LTS-GelMA bioresin, we explored the possibility to modulate the permeability of the hydrogel via the introduction of microporosity within the bioprinted structures. Besides working with hydrogels displaying relatively low polymer content and compressive stiffness, in order to enhance cell-material interactions, as well as to promote nutrient transport across a bioprinted construct, a unique ATPE strategy has been recently introduced [ [39] , [40] , [41] ]. Here, we utilized PEO as a porogen to emulsify the LTS-GelMA bioresin.…”

“…To demonstrate the further possibility to introduce microporosity within the bioprinted hydrogel bulk, the bioresin formulation was modified to form an aqueous two-phase emulsion (ATPE) bioresin [ [39] , [40] , [41] ]. For the ATPE bioresin preparation, LTS-GelMA solution and porogen solution were dissolved in PBS separately.…”

In Situ 3D Bioprinting Living Photosynthetic Scaffolds for Autotrophic Wound Healing

“…Additionally, owing to the design flexibility and anatomical accuracy, 3D bioprinting technology has been widely employed for the fabrication of both living cell-laden and acellular biomimetic constructs in tissue engineering [ 29 – 34 ]. In particular, some attempts have been performed by in situ bioprinting of tissue constructs at defect sites, which enables accurate filling of irregular-shaped defects and concurrence of in vivo integration with native tissues [ 35 – 40 ]. Thus, it is conceivable that the in situ bioprinting of the photosynthetic microalgae into wound sites would provide a self-adaptive platform with an autotrophic oxygen supply for versatile wound healing.…”

Digital Light Processing Based Bioprinting with Composable Gradients

“…Recent developments in producing hydrogel microspheres and porous hydrogels utilizing the aqueous two‐phase system have attracted much attention. [ 51–53 ] To fabricate the 3D porous gradient architecture, 10 wt% GelMA bioink containing human MSCs was mixed with the 10 wt% GelMA solution containing the porogen. By adjusting the flow ratios of the two bioinks, we formulated the 10 wt% GelMA bioinks with 3.0, 1.5, and 0.5 wt% of the porogen, resulting in three gradual zones featuring different pore sizes as observed from the optical micrographs (Figure S5a,b, Supporting Information).…”

“…The existent of porogen effectively formed pores in the bioprinted hydrogel constructs, facilitating the diffusion of nutrients and oxygen and the removal of wastes, thus providing an environment to promote cell spreading and proliferation. [ 51–53 ]…”