Abstract
The immobilization of enzymes into polymer hydrogels is a versatile approach to improve their stability and utility in biotechnological and biomedical applications. However, these systems typically show limited enzyme activity, due to unfavorable pore dimensions and low enzyme accessibility. Here, 3D jet writing of water-based bioinks, which contain preloaded enzymes, is used to prepare hydrogel scaffolds with well-defined, tessellated micropores. After 3D jet writing, the scaffolds are chemically modified via photopolymerization to ensure mechanical stability. Enzyme loading and activity in the hydrogel scaffolds is fully retained over 3 d. Important structural parameters of the scaffolds such as pore size, pore geometry, and wall diameter are controlled with micrometer resolution to avoid mass-transport limitations. It is demonstrated that scaffold pore sizes between 120µm and 1mm can be created by 3D jet writing approaching the length scales of free diffusion in the hydrogels substrates and resulting in high levels of enzyme activity (21.2% activity relative to free enzyme). With further work, a broad range of applications for enzyme-laden hydrogel scaffolds including diagnostics and enzymatic cascade reactions is anticipated.
Highlights
The immobilization of enzymes into polymer hydrogels is a versatile approach are conventionally used in homogenous to improve their stability and utility in biotechnological and biomedical applications
Commercial utilization of enzymes is hampered by the lack of stability and limited recycling capacity.[2]
Enzyme immobilization enables sizes between 120 μm and 1 mm can be created by 3D jet writing approaching the use in continuous flow reactors, which the length scales of free diffusion in the hydrogels substrates and resulting in high levels of enzyme activity (21.2% activity relative to free enzyme)
Summary
The prerequisite for incorporating biologically active materials into structures is a water-based jet ink which maintains the stability and activity of the enzymes during the production process. PAA concentration of more than 7% [w/v] were necessary and a water content of 30% [v/v] or less was ideal for a stable jet process. The suitability of an ink for an electrohydrodynamic jetting process depends on effective macromolecular entanglement. This leads to relatively high weight fractions of polymer compared to other hydrogel printing methods and can result in undesired aggregation of PEGDA. Comparable to the results obtained for the pure PEGDA solution, the cluster size and shape is too large to be resolved. An influence of PEGDA in the hydrogel structure induced by PAA after UV-curing can be excluded
Sign-in/Register to view highlights & summary 
Published Version (
Free)
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call