Engineered Living Materials based on Adhesin-mediated Trapping of Programmable Cells

Abstract

5 Stichting PAMM, Laboratory for pathology and medical microbiology, De Run 6250, 5504 DL Veldhoven 6 Laboratory of Physical Chemistry 7 Molecular biosensing for medical diagnostics 8 Laboratory of protein engineering 1-4, 6-8 : Abstract:Engineered living materials have the potential for wide-ranging applications such as biosensing and treatment of diseases. Programmable cells provide the functional basis for living materials, however, their release into the environment raises numerous biosafety concerns. Current designs that limit the release of genetically engineered cells typically involve the fabrication of multi-layer hybrid materials with sub-micron porous matrices. Nevertheless the stringent physical barriers limit the diffusion of macromolecules and therefore the repertoire of molecules available for actuation in response to communication signals between cells and their environment. Here, we engineer a first-of-its-kind living material entitled 'Platform for Adhesin-mediated Trapping of Cells in Hydrogels' (PATCH). This technology is based on engineered E. coli that displays an adhesion protein derived from an Antarctic bacterium with high affinity for glucose. The adhesin stably anchors E. coli in dextran-based hydrogels with large pore diameters (10-100 µm) and reduces the leakage of bacteria into the environment by up to 100-fold. As an application of PATCH, we engineered E. coli to secrete lysostaphin via the Type 1 Secretion System and demonstrated that living materials containing this E. coli inhibit the growth of S. aureus, including the strain resistant to methicillin (MRSA). Our tunable platform allows stable integration of programmable cells in dextran-based hydrogels without compromising free diffusion of macromolecules and could have potential applications in biotechnology and biomedicine. Introduction:Synthetic biology aims to design programmable cells that combine sensing and molecular computing operations with on-demand production of proteins that have a broad spectrum of therapeutic applications [1][2][3][4]. Engineered living materials (ELMs) integrate genetically engineered cells with free standing materials and represent a new class of environmentally responsive living devices with designer physicochemical and material properties [5][6][7]. Ideally, ELMs provide mechanical robustness to engineered cells, prevent their leakage to the environment and allow cells to be viable for extended periods of time. The containment of genetically-modified microorganisms (GMMs) within various materials has become a grand challenge for future synthetic biology applications [8]. To date, strategies for containing GMMs inside a living device are based on the physical confinement by multi-layer materials [9][10][11]. Hybrid micro-patterned devices combining layers of elastomer and microporous hydrogel enabled the exchange of information with surrounding environment via diffusion of chemical inducers and their sensing by GMMs while displaying high mechanical resilience [10]. Nevertheless, the low porosity ...

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