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{"Abstract":["Natural biological materials are formed by self-assembly processes and\n catalyze a myriad of reactions. Here, we report a programmable molecular\n assembly of designed synthetic polymers with engineered Bacillus subtilis\n spores. The bacterial spore-based materials possess modular mechanical and\n functional properties derived from the independent design and assembly of\n synthetic polymers and engineered spores .  We discovered that\n phenylboronic acid (PBA) derivatives form tunable and reversible dynamic\n covalent bonds with the spore surface glycan. Spore labeling was performed\n using fluorescent PBA probes and monitored by fluorescence microscopy and\n spectroscopy. Binding affinities of PBA derivatives to spore surface\n glycan was controlled by aryl substituent effects. On the basis of this\n finding, PBA-functionalized statistical copolymers were synthesized and\n assembled with B. subtilis spores to afford macroscopic materials that\n exhibited programmable stiffness, self-healing, prolonged dry storage, and\n recyclability. These material properties could be examined using shear\n rheology, tensile testing, and NMR experiments.  Integration of engineered\n spores with surface enzymes yielded reusable biocatalytic materials with\n exceptional operational simplicity and high benchtop stability. The\n reaction progress of the biocatalyses could be monitored with fluorescence\n specroscopy and absorption measurements, while spore leakage could be\n monitored by changes in solution turbidity (OD600). The use of bacterial\n spores as an active partner in dynamic covalent crosslinking sets our\n material apart from previous examples and grants control over\n biocontainment as well as the subsequent fate of the spores through\n stimuli-responsive reversal of the crosslink."],"Methods":["All experimental methods are briefly described in the README.md file, and\n fully detailed in the Supporting Information file for the paper article\n "Catalytic materials enabled by a programmable assembly of synthetic\n polymers and engineered bacterial spores"."]} 

Abstract Objective. The Utah array is widely used in both clinical studies and neuroscience. It has a strong track record of safety. However, it is also known that implanted electrodes promote the formation of scar tissue in the immediate vicinity of the electrodes, which may negatively impact the ability to record neural waveforms. This scarring response has been primarily studied in rodents, which may have a very different response than primate brain. Approach. Here, we present a rare nonhuman primate histological dataset ( n = 1 rhesus macaque) obtained 848 and 590 d after implantation in two brain hemispheres. For 2 of 4 arrays that remained within the cortex, NeuN was used to stain for neuron somata at three different depths along the shanks. Images were filtered and denoised, with neurons then counted in the vicinity of the arrays as well as a nearby section of control tissue. Additionally, 3 of 4 arrays were imaged with a scanning electrode microscope to evaluate any materials damage that might be present. Main results. Overall, we found a 63% percent reduction in the number of neurons surrounding the electrode shanks compared to control areas. In terms of materials, the arrays remained largely intact with metal and Parylene C present, though tip breakage and cracks were observed on many electrodes. Significance. Overall, these results suggest that the tissue response in the nonhuman primate brain shows similar neuron loss to previous studies using rodents. Electrode improvements, for example using smaller or softer probes, may therefore substantially improve the tissue response and potentially improve the neuronal recording yield in primate cortex.