Carbonic anhydrases convert CO2 to bicarbonate at a high turnover rate up to 106 s–1, but their actual applications in CO2 conversion processes are hampered by their poor stability. This study reports highly loaded and stabilized bovine carbonic anhydrase (bCA) upon being immobilized onto electrospun polymer nanofibers in the form of enzyme precipitate coating (EPC). The EPC protocol, consisting of enzyme covalent attachment, precipitation, and cross-linking, maintained 65.3% of initial activity even after being incubated in aqueous solution at room temperature under shaking at 200 rpm for 868 days. EPC also showed strong resistance to the treatment of the metal chelation agent, ethylenediaminetetraacetic acid, and molecular dynamic simulation was carried out to elucidate the prevention of metal leaching from the active site of bCA upon being cross-linked in the form of EPC. Highly stable EPC with high bCA loading was employed for the conversion of bubbling CO2 to bicarbonate, and the bicarbonate solution was utilized as a carbon source for expedited microalgae growth in a separate bioreactor. The addition of EPC in the bubbling CO2 reactor resulted in 134 and 231% accelerated microalgae growths compared to the controls with and without 25 mM sodium bicarbonate, respectively. EPC with high enzyme loading and unprecedentedly successful stabilization of enzyme stability has a great potential to be used for the development of various enzyme-mediated CO2 conversion and utilization technologies.

The current practice of cytokine-based immunotherapy relies on high doses and multiple injections of cytokine agents, which raises patients' inconvenience and economic burden. Here, sustainable and recyclable cytokine delivery based on short and injectable polymer fibers immobilized with interleukin (IL)-2 and IL-15 is demonstrated, which can be retained at the target tumor sites upon injection. In detail, electrospun polylactic acid (PLA) fibers are treated with aqueous ethanol solution for their dispersion, increasing the interfiber space for highly efficient biomolecule conjugation, and further immobilized with protein G via enzymatic dopamine coating. The protein G-immobilized PLA fibers are cut into short fibers using a microtome, and filtering is performed to collect injectable short PLA (sPLA) fibers with the lengths of 15-100 µm. These sPLA fibers are further loaded with cytokines via the interaction between protein G and Fc, and cytokine-loaded sPLA (Cyto-sPLA) fibers are injected near the tumor sites using a syringe. The administration of Cyto-sPLA fibers efficiently suppresses the tumor growth up to 70% by reinvigorating nonfunctional T cells to a functional state that can kill tumors in a sustainable and recyclable manner. The injectable sPLA-fiber platform can be employed as a carrier for the efficient delivery of various agents in vivo.

No abstract

In article number https://doi.org/10.1002/adfm.201808361, Jungbae Kim, Hang‐Rae Kim, and co‐workers inject cytokine‐immobilized short polylactic acid (PLA) fibers (Cyto‐sPLA) near a tumor to reinvigorate nonfunctional T cells. The administration of Cyto‐sPLA fibers kills tumor cells and ultimately effectively inhibits tumor growth. Injectable Cyto‐sPLA fibers have great potential for the development of anticancer therapeutics.