High-density brush-shaped polymer lipids reduce anti-PEG antibody binding for repeated administration of mRNA therapeutics
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Metastable phase-separated droplet generation and long-time DNA enrichment by laser-induced Soret effect
Spatiotemporally controlled laser-induced phase separation (LIPS) offers unique research avenues and has potential for biological and biomedical applications. However, LIPS conditions often have drawbacks for practical use, which limit their applications. For instance, LIPS droplets are unstable and diminish after the laser is terminated. Here, we developed a novel LIPS method using laser-induced Soret effect with a simple setup to solve these problems. We generate liquid-liquid phase-separated (LLPS) droplets using LIPS in an aqueous two-phase system (ATPS) of dextran (DEX) and polyethylene glycol (PEG). When DEX-rich droplets were generated in the DEX/PEG mix on the phase boundary, the droplets showed unprecedently high longevity; the DEX droplets were retained over 48 h. This counterintuitive behaviour suggests that the droplet is in an unknown metastable state. By exploiting the capability of DEX-rich droplets to enrich nucleic acid polymers, we achieved stable DNA enrichment in LIPS DEX droplets with a high enrichment factor of 1400 ± 400. Further, we patterned DNA-carrying DEX-rich droplets into a designed structure to demonstrate the stability and spatiotemporal controllability of DEX-rich droplet formation. This is the first report for LIPS droplet generation in a DEX/PEG system, opening new avenues for biological and medical applications of LIPS.
Anti-icing properties of nonionic/hydrophilic concentrated polymer brushes and mechanistic insights via their swollen-state analysis
Anti-icing surfaces are important to prevent snow and ice accumulation, which can pose significant risks. Here, we analyze the anti-icing performance of concentrated polymer brushes (CPBs) consisting of a versatile nonionic/hydrophilic monomer and discuss the low-temperature properties of the CPB-retaining water. The anti-icing functionality is evaluated by measuring the ice adhesion strength as a function of the temperature and the structural parameters (e.g., density and length) of the polymer brushes. We demonstrate that only the CPB region (σ* ≥ 0.15) exhibits both high anti-icing functionality and excellent durability. Furthermore, the thickening of the CPBs is key to achieving a detailed characterization of the water present in the CPBs at low temperatures using in situ microscopic Fourier-transform infrared spectroscopy and differential scanning calorimetry. These results suggest that the water effectively remaining via quasi-equilibrium partial deswelling formed a lubricating layer, contributing to high anti-icing functionality and durability.
Mixed-layer lipidomes suggest offshore transport of energy-rich and essential lipids by cyclonic eddies
Mesoscale eddies are ubiquitous features in the ocean affecting the cycles of nutrients and carbon. Cyclonic eddies formed in Eastern Boundary Upwelling Systems can substantially modulate primary production by phytoplankton and the vertical and lateral export of organic carbon. However, the impact of eddy activity on the biochemical composition of eukaryotic phytoplankton, bacteria and archaea and associated consequences for carbon and energy flows are largely unknown. Here, we investigated the microbial lipidome in the surface ocean in and around a cyclonic eddy formed in the coastal upwelling system off Mauritania. We show that the eddy contained almost three times the amount of lipids compared to the surrounding open-ocean and coastal waters. The eddy lipid signature with energy-rich triacylglycerols and essential fatty acid-containing membrane lipids of eukaryotic phytoplankton origin was further significantly different from the ambient waters. Strong variability in lipid distributions within the eddy was related to differences in microbial community composition. Estimates indicate that in the Mauritanian upwelling area, as much as 9.7 ± 2.0 gigagrams of lipid carbon per year is delivered to the open ocean by coastal cyclonic eddies potentially fueling higher trophic levels and contributing to the maintenance of secondary productivity and carbon export offshore.
Anionic lipids direct efficient microfluidic encapsulation of stable and functionally active proteins in lipid nanoparticles
Because proteins do not efficiently pass through the plasma membrane, protein therapeutics are limited to target ligands located at the cell surface or in serum. Lipid nanoparticles can facilitate delivery of polar molecules across a membrane. We hypothesized that because most proteins are amphoteric ionizable polycations, proteins would associate with anionic lipids, enabling microfluidic chip assembly of stable EP-LNPs (Encapsulated Proteins in Lipid NanoParticles). Here, by employing anionic lipids we were able to efficiently load proteins into EP-LNPs at protein:lipid w:w ratios of 1:20. Several proteins with diverse molecular weights and isoelectric points were encapsulated at efficiencies of 70 75%–90% and remained packaged for several months. Proteins packaged in EP-LNPs efficiently entered mammalian cells and fungal cells with cell walls. The proteins delivered intracellularly were functional. EP-LNPs technology should improve cellular delivery of medicinal antibodies, enzymes, peptide antimetabolites, and dominant negative proteins, opening new fields of protein therapeutics
On-patient medical record and mRNA therapeutics using intradermal microneedles
Medical interventions often require timed series of doses, thus necessitating accurate medical record-keeping. In many global settings, these records are unreliable or unavailable at the point of care, leading to less effective treatments or disease prevention. Here we present an invisible-to-the-naked-eye on-patient medical record-keeping technology that accurately stores medical information in the patient skin as part of microneedles that are used for intradermal therapeutics. We optimize the microneedle design for both a reliable delivery of messenger RNA (mRNA) therapeutics and the near-infrared fluorescent microparticles that encode the on-patient medical record-keeping. Deep learning-based image processing enables encoding and decoding of the information with excellent temporal and spatial robustness. Long-term studies in a swine model demonstrate the safety, efficacy and reliability of this approach for the co-delivery of on-patient medical record-keeping and the mRNA vaccine encoding severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). This technology could help healthcare workers make informed decisions in circumstances where reliable record-keeping is unavailable, thus contributing to global healthcare equity.
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