Gene expression dynamics in input-responsive engineered living materials programmed for bioproduction.

Area of Science:

• Synthetic Biology
• Biomaterials Engineering
• Microbial Biotechnology

Background:

• Engineered living materials (ELMs) using microbes in hydrogels show promise for bioproduction.
• Long-term gene expression dynamics in ELMs remain poorly understood.
• Understanding gene expression is crucial for optimizing ELM functionality.

Purpose of the Study:

• Investigate long-term gene expression dynamics in microbial ELMs.
• Assess the impact of different microbes and hydrogel matrices on gene expression.
• Demonstrate sustained and dynamic bioproduction capabilities in ELMs.

Main Methods:

• Engineered E. coli and S. cerevisiae encapsulated in hydrogels (F127-BUM, BSA-PEGDA).
• Direct gene expression measurements and CRISPR transcriptional activation (CRISPRa).
• Multi-week bioproduction cycling with chemical inducers.

Main Results:

• Inducible genetic programs in ELMs sustained gene expression for multiple weeks, significantly longer than planktonic cells.
• ELMs retained up to 97% of initial gene expression capacity after repeated induction cycles.
• Demonstrated multi-week, scheduled bioproduction switching of enzymes and pigments in S. cerevisiae ELMs.

Conclusions:

• Microbial ELMs exhibit robust, long-term, and dynamically responsive gene expression capabilities.
• These findings suggest long-term genetic expression is a general property of microbial ELMs.
• Developed approaches enable tailored ELM functions for diverse advanced applications.