Solute Transport in Engineered Living Materials Using Bone‐Inspired Microscale Channel Networks

Abstract

Engineered living materials (ELMs) are an emerging class of materials that are synthesized and/or populated by living cells to achieve novel functionalities including self‐healing and sensing. Providing nutrients to living cells within an ELM over prolonged periods remains a major technical challenge that limits the service life of ELMs. Bone maintains living cells for decades by delivering nutrients through a network of nanoscale channels punctuated by microscale pores. Nutrient transfer in bone is enabled by mechanical loading experienced by the material during regular use. Here we identify the geometric traits of the network of channels and pores that can be used in engineered living materials to allow mechanical loading to enable nutrient delivery to resident cell populations in a manner seen in bone. Transport occurs when deformation in the microscale pore network exceeds the volume of the connecting channels. Computational models show that transport is enhanced at greater loading magnitudes and lower loading frequencies. The computational results are confirmed using experiments with microfluidic systems. Our findings provide quantitative design principles for channel‐pore networks capable of sustained delivery of nutrients to living cells within materials.This article is protected by copyright. All rights reserved.

Mycelium as a scaffold for biomineralized engineered living materials

“…We also demonstrated that mycelium scaffolds can permit the construction of specimens with complex internal microarchitectures. Osteonal bone was chosen as a demonstration since this microarchitecture is well-known to contribute to bone's excellent properties while provide important physiological functions 20,22,24,43,44 . Mycelium scaffolds were bacteriallybiomineralized into concentric rings that mimic the lamellae within osteons, and then were mineralized together with a dispersed sand phase within a beam-shaped mold.…”

“…Current biomineralized ELM scaffolds do not permit control over internal microarchitecture, but the material properties of biomineralized natural composites often benefit from complex internal porosity or interfaces 19,22,38,40,44 . With the usage of bacterially-mineralized fungal scaffolds (BICP) in this study, we had an opportunity to control the internal microarchitecture of biomineralized ELMs for the first time.…”

“…Importantly, these restrictions limit the amount of time a material can perform functions unique to living materials (e.g., biomineralization, photosynthesis, selfhealing). A third motivation is that biopolymer scaffolds may confer control over the scaffold architecture in a manner that has not been available when working with hydrogels, which could allow complex microarchitectures of biomineralized ELMs for the first time 21,22 . Fungal mycelium is a promising candidate for scaffolding third-generation biomineralized ELMs.…”

“…Natural composite materials with desirable strength and toughness commonly have complex, optimized internal microarchitectures (e.g., bone, coral, nacre, glass sponges) 19,37,38,[40][41][42] . Furthermore, designed internal porosity could be important for the transport of biomineralizing solutions or cellular nutrition in a scaffolded structure 21,22 .…”