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Plant-derived nanovesicles such as bilberries nanovesicles (BNVs) show immense promise as next-generation biotherapeutics and functional food ingredients; however, their isolation, purification, and storage on a large scale remain a challenge. In this study, biocompatible and nanostructured composite all-cellulose membranes are introduced as a scalable and straightforward approach to the isolation of BNV. The membranes consisting of a cellulose acetate matrix infused with anionic or cationic nanocelluloses promoted selective capture of BNVs through electrostatic and size-exclusion-mediated depth filtration. Furthermore, the surface of the composite membrane acted as a storage matrix for BNVs, ensuring their prolonged stability at 4 °C. The BNVs stored in the membrane could be promptly released through elution assisted by low-pressure vacuum filtration or diffusion in liquid media. The morphology, bioactivity, and stability of the extracted BNVs were preserved, and the release rate of BNVs in different cell cultures could be regulated, facilitating their use for local therapy. Consequently, this approach paves the way for the scalable production, purification, and storage of nanovesicles and advances their use in biotherapeutics and functional foods.

Under the simultaneous use of pressure-driven flow and DC electric field, migration of particles inside microfluidic channels exhibits intricate focusing dynamics. Available experimental and analytical studies fall short in giving a thorough explanation to particle equilibrium states. Also, the understanding is so far limited to the results based on Newtonian and neutral viscoelastic carrier fluids. Hence, a holistic approach is taken in this study to elaborate the interplay of governing electrophoretic and slip-induced/elastic/shear gradient lift forces. First, we carried out experimental studies on particle migration in Newtonian, neutral viscoelastic, and polyelectrolyte viscoelastic media to provide a comprehensive understanding of particle migration. The experiments with the viscoelastic media led to contradictory results with the existing explanations. Then, we introduced the Electro-Viscoelastic Migration (EVM) theory to give a unifying explanation to particle migration in Newtonian and viscoelastic solutions. Confocal imaging with fluorescent-labeled polymer solutions was used to explore the underlying migration behavior. A surprising outcome of our results is the formation of cross-sectionally nonuniform viscoelasticity that may have unique applications in microfluidic particle focusing.

We introduce a droplet-based biomolecular detection platform using robust, versatile, and low-cost superhydrophilic patterned superhydrophobic surfaces. Benefitting from confinement and evaporation-induced shrinkage of droplets on wetted patterns, we show enrichment-based biomolecular detection using very low sample volumes. First, we developed a glucose assay using fluorescent polydopamine (PDA) based on enhancement of PDA emission by hydrogen peroxide (H 2 O 2 ) produced in enzyme-mediated glucose oxidation reaction. Incubation in evaporating droplets resulted in brighter fluorescence compared to that in bulk solutions. Droplet assay was highly sensitive toward increasing glucose concentration while that in milliliter-volume solutions resulted in no fluorescence enhancement at similar time scales. This is due to droplet evaporation that increased the reaction rate by causing enrichment of PDA and glucose/glucose oxidase as well as increased concentration of H 2 O 2 generated in shrinking droplet. Second, we chemically functionalized wetted patterns with single-stranded DNA and developed fluorescence-based DNA detection to demonstrate the adaptability of the patterned surfaces for a different class of assay. We achieved detection of glucose and DNA with concentration down to 130 μM and 200 fM, respectively. Patterned superhydrophobic surfaces with their simple production, sensitive response, and versatility present potential for bioanalysis from low sample volumes., Competing Interests: The authors declare no competing financial interest.