Solute Transport in Engineered Living Materials using Bone Inspired Microscale Channel Networks

Engineered living materials (ELMs) are an emerging class of materials that is synthesized and/or populated by living cells. Maintaining living cells within an ELM over prolonged periods remains a major technical challenge that limits the service life of a material. Biological materials regularly maintain robust populations of living cells. 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 during regular use. Here we identify the characteristics of channel-pore network geometries and external mechanical loading that can be used in engineered living materials to deliver nutrients to resident cell populations. 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 load magnitudes and lower loading frequencies and are consistent with experimental validation using microfluidic systems. Our findings provide quantitative design principles for channel-pore networks capable of delivering nutrients to materials designed to house living cells.