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This work introduces an environmentally benign and degradable elastomer, poly(glycerol sebacate) with calcium carbonate (PGS-CaCO 3 ), for use in soft robotics. Development of greener materials like PGS-CaCO 3 contributes to robot designs that do not require retrieval and can safely degrade in the natural environment. A simplified synthesis method of PGS was used to create elastomer sheets, which were laser cut/rastered then laminated with cyanoacrylate glue into pneumatic soft actuators. The modified polymer synthesis method is accessible for roboticists and the three chemicals used are non-hazardous and inexpensive. Three accordion-style pneumatic actuators (3, 4 and 5 chambers) were characterized for free displacement and blocked force in both linear extension and curling motions, and an additional four 3-chambered actuators were also tested to leakage and failure. Material characterization of PGS-CaCO 3 samples of all ages gave: ultimate tensile strength (UTS) from 48 to 160 kPa, elongation percent at UTS from 157 to 242%, moduli from 45 to 154 kPa, average resilience of 88% at 100 cycles, and maximum compressive force of 246 N at 50% strain. After being in an approximately 50-55 C compost pile for 7 days, the polymer visibly degraded and had an average mass loss of 20% across 12 samples. PGS's strength, elasticity, biodegradability and chemical safety make it a desirable option for roboticists looking to leverage sustainable materials. PGS may also prove a potential green alternative for robotics applications in ubiquitous environmental and infrastructure sensing.

Despite advancements in tissue engineering, the methods used to generate three-dimensional (3D) in vitro models for rapid screening and characterization studies remain time and labor intensive. Bioprinting offers an opportunity to offset these limitations by providing a scalable, high-throughput method with precise control over biomaterial scaffold and cellular deposition. However, the process of formulating bioinks can be complex in terms of balancing the mechanical integrity of a bioscaffold and viability of cells. One key factor, especially in alginate-based bioinks, is the rate of bioscaffold dissolution. It must allow cells to replace the bioscaffold with extracellular matrix (ECM), yet remain durable during extended tissue culture. This study uses a Design of Experiments (DoE) approach to understand the dependencies of multiple variables involved in the formulation and processing of an alginate-based bioink. The focus of the DoE was to understand the effects of hydrogel composition on bioink durability while maintaining cell viability. Three ingredients were varied in all: alginate, nanocellulose, and fibrinogen. Their effects on the bioink were then measured with respect to extrudability, strength, and stiffness as determined by dynamic mechanical analysis (DMA). The DoE demonstrated that mechanical integrity increased with increasing alginate concentration. In contrast, fibrinogen and nanofibril concentration had no statistically significant effect. The optimized ink containing fibroblasts was printable using multiple nozzle sizes while also supporting fibroblast cell viability. DMA characterization further showed that the composition of the cell culture medium did not modulate the degradation rate of the hydrogel. Ultimately, the study outlines a methodology for formulating a bioink that will result in robust bioscaffolds for in vitro model development.

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Increasing interest in the detection of biogenic signatures, such as amino acids, on icy moons and bodies within our solar system has led to the development of compact in situ instruments. Given the expected dilute biosignatures and high salinities of these extreme environments, purification of icy samples before analysis enables increased detection sensitivity. Herein, we outline a novel compact cation exchange method to desalinate proteinogenic amino acids in solution, independent of the type and concentration of salts in the sample. Using a modular microfluidic device, initial experiments explored operational limits of binding capacity with phenylalanine and three model cations, Na + , Mg 2+ , and Ca 2+ . Phenylalanine recovery (94–17%) with reduced conductivity (30–200 times) was seen at high salt-to-amino-acid ratios between 25:1 and 500:1. Later experiments tested competition between mixtures of 17 amino acids and other chemistries present in a terrestrial ocean sample. Recoveries ranged from 11% to 85% depending on side chain chemistry and cation competition, with concentration shown for select high affinity amino acids. This work outlines a nondestructive amino acid purification device capable of coupling to multiple downstream analytical techniques for improved characterization of icy samples at remote ocean worlds.