3D cell printing (bioprinting) is rapidly emerging as a key biofabrication strategy for engineering tissue constructs with physiological form and complexity. [1][2][3][4] In practice, this process involves layer-by-layer deposition of a cell-laden bioink resulting in the additive manufacture of a patterned architecture with different cell types, growth factors, or mechanical cues, which are positioned with far greater precision than can be achieved with conventional scaffold-based tissue engineering. [ 5 ] While there have been signifi cant advances in printing technology, [ 6,7 ] progress has been limited by the rate of development of bioinks that are compatible with both 3D printing and tissue engineering. [ 8 ] These materials must be able to withstand extrusion, maintain structural fi delity for long time periods, and permit adequate nutrient diffusion, all under cytocompatible conditions. Due to their intrinsic porosity and capacity for high nutrient loading, hydrogels are the most promising candidate for bioink design, [ 9 ] particularly when gelation can be externally triggered using chemical bonding, [ 10 ] photoinduced crosslinking, [ 11 ] thermal setting, [ 12 ] or shear-thinning. [ 13 ] However, integrating these factors into a system while maintaining printability, structural persistence, and cell viability, is an enduring challenge. [ 14 ] Pluronic block copolymers of poly(ethylene oxide-b-propylene oxide-b-ethylene oxide) present a possible pathway to print gelation, as they undergo a sol-gel transition upon heating near physiological temperatures. Here, elevating the temperature of these non-ionic surfactants reduces the

We present a new methodology for the generation of discrete molecularly dispersed enzyme− polymer−surfactant bioconjugates. Significantly, we demonstrate that >3-fold increase in the catalytic efficiency of the diffusion-limited phosphotriesterase arPTE can be achieved through sequential electrostatic addition of cationic and anionic polymer surfactants, respectively. Here, the polymer surfactants assemble on the surface of the enzyme via ion exchange to yield a compact corona. The observed rate enhancement is consistent with a mechanism whereby the polymer−surfactant corona gives rise to a decrease in the dielectric constant in the vicinity of the active site of the enzyme, accelerating the rate-determining product diffusion step. The facile methodology has significant potential for increasing the efficiency of enzymes and could therefore have a substantially positive impact for industrial enzymology.

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A.W. Perriman and co‐workers describe a new cell‐containing hybrid bio‐ink that allows the 3D printing of physiological architectures with templated micropores on page 1724. The printed constructs are then used in cartilage and bone tissue engineering, giving rise to well‐distributed extracellular matrix components.