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Living cells can impart materials with advanced functions, such as senseand-respond, chemical production, toxin remediation, energy generation and storage, self-destruction, and self-healing. Here, an approach is presented to use light to pattern Escherichia coli onto diverse materials by controlling the expression of curli fibers that anchor the formation of a biofilm. Different colors of light are used to express variants of the structural protein CsgA fused to different peptide tags. By projecting color images onto the material containing bacteria, this system can be used to pattern the growth of composite materials, including layers of protein and gold nanoparticles. This is used to pattern cells onto materials used for 3D printing, plastics (polystyrene), and textiles (cotton). Further, the adhered cells are demonstrated to respond to sensory information, including small molecules (IPTG and DAPG) and light from light-emitting diodes. This work advances the capacity to engineer responsive living materials in which cells provide diverse functionality.

A route to advanced multifunctional materials is to embed them with living cells that can perform sensing, chemical production, energy scavenging, and actuation. A challenge in realizing this potential is that the conditions for keeping cells alive are not conducive to materials processing and require a continuous source of water and nutrients. Here, we present a 3D printer that can mix material and cell streams in a novel printhead and build 3D objects (up to 2.5 cm by 1 cm by 1 cm). Hydrogels are printed using 5% agarose, which has a low melting temperature (65 o C) consistent with thermophilic cells, a rigid storage modulus (G'= 6.5 x 10 4 ), exhibits shear thinning, and can be rapidly hardened upon cooling to preserve structural features. Spores of B. subtilis are printed within the material and germinate on its exterior, including spontaneously in cracks and new surfaces exposed by tears. By introducing genetically engineered bacteria, the materials can sense chemicals (IPTG, xylose, or vanillic acid). Further, we show that the spores are resilient to extreme environmental stresses, including desiccation, solvents (ethanol), high osmolarity (1.5 mM NaCl), 365 nm UV light, and g-radiation (2.6 kGy). The construction of 3D printed materials containing spores enables the living functions to be used for applications that require long-term storage, in-field functionality, or exposure to uncertain environmental stresses.

Antibiotics for treating urogenital Chlamydia trachomatis infection in men and non-pregnant women (Review)

No abstract