A hybrid soft material robotic end-effector for reversible in-space assembly of strut components.

Based on the NASA in-Space Assembled Telescope (iSAT) study (Bulletin of the American Astronomical Society, 2019, 51, 50) which details the design and requirements for a 20-m parabolic in-space telescope, NASA Langley Research Center (LaRC) has been developing structural and robotic solutions to address the needs of building larger in-space assets. One of the structural methods studied involves stackable and collapsible modular solutions to address launch vehicle volume constraints. This solution uses a packing method that stacks struts in a dixie-cup like manner and a chemical composite bonding technique that reduces weight of the structure, adds strength, and offers the ability to de-bond the components for structural modifications.

Spatial control of gene expression within a scaffold by localized inducer release.

Gene expression can be controlled in genetically modified cells by employing an inducer/promoter system where presence of the inducer molecule regulates the timing and level of gene expression. By applying the principles of controlled release, it should be possible to control gene expression on a biomaterial surface by the presence or absence of inducer release from the underlying material matrix, thus avoiding alternative techniques that rely upon uptake of relatively labile DNA from material surfaces. To evaluate this concept, a modified ecdysone-responsive gene expression system was transfected into B16 murine cells and the ability of an inducer ligand, which was released from elastomeric poly(ester urethane) urea (PEUU), to initiate gene expression was studied.

Semi-synthetic ecdysteroids as gene-switch actuators: synthesis, structure-activity relationships, and prospective ADME properties.

The ligand-inducible, ecdysteroid receptor (EcR) gene-expression system can add critical control features to protein expression in cell and gene therapy. However, potent natural ecdysteroids possess absorption, distribution, metabolism and excretion (ADME) properties that have not been optimised for use as gene-switch actuators in vivo. Herein we report the first systematic synthetic exploration of ecdysteroids toward modulation of gene-switch potency.

Ecdysteroid ligand-receptor selectivity--exploring trends to design orthogonal gene switches.

A set of thirty-two natural and ten semisynthetic ecdysteroids was assayed in murine 3T3 cells across ten different ecdysteroid receptor (EcR) ligand-binding domains derived from nine arthropod species in an engineered gene switch format. Among the ecdysteroids tested, the most biologically widespread ecdysteroid, 20-hydroxyecdysone (20E), was moderately and consistently potent across the tested EcRs. The most potent ligand-receptor combination (EC(50) = 0.

Synthesis and SAR of cis-1-benzoyl-1,2,3,4-tetrahydroquinoline ligands for control of gene expression in ecdysone responsive systems.

A library of 35 cis-1-benzoyl-2-methyl-4-(phenylamino)-1,2,3,4-tetrahydroquinolines was prepared. The compounds bore various substitutuents on the benzoyl ring, at the 4-position of the phenylamino ring and at the 6-position of the tetrahydroquinoline ring. The compounds were assayed for their ability to cause expression of a reporter gene downstream of an ecdysone response element in a mammalian cell line engineered to express the ecdysone receptor from Aedes aegypti.