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Tran Thomassen posted an update 7 months, 3 weeks ago
We show that their porosities can be tuned by controlling the lobe size and temperature.We study the permeability and selectivity (‘permselectivity’) of model membranes made of polydisperse polymer networks for molecular penetrant transport, using coarse-grained, implicit-solvent computer simulations. In our work, permeability P is determined on the linear-response level using the solution-diffusion model, P = KDin, i.e., by calculating the equilibrium penetrant partition ratio K and penetrant diffusivity Din inside the membrane. We vary two key parameters, namely the network-network interaction, which controls the degree of swelling and collapse of the network, and the network-penetrant interaction, which tunes the selective penetrant uptake and microscopic energy landscape for diffusive transport. selleck We find that the partitioning K covers four orders of magnitude and is a non-monotonic function of the parameters, well interpreted by a second-order virial expansion of the free energy of transferring one penetrant from a reservoir into the membrane. Moreover, we find that the penetrant diffusivity Din in the polydisperse networks, in contrast to highly ordered membrane structures, exhibits relatively simple exponential decays. We propose a semi-empirical scaling law for the penetrant diffusion that describes the simulation data for a wide range of densities and interaction parameters. The resulting permeability P turns out to follow the qualitative behavior (including maximization and minimization) of partitioning. However, partitioning and diffusion are typically anti-correlated, yielding large quantitative cancellations, controlled and fine-tuned by the network density and interactions, as rationalized by our scaling laws. We finally demonstrate that even small changes of network-penetrant interactions, e.g., by half a kBT, modify the permselectivity by almost one order of magnitude.Carbon nanotubes (CNTs) are cylindrical tubular nanomaterials made of carbon with excellent electrical conductivity, thermal conductivity, and mechanical strength. The material is applied to improve performance in various industrial products. CNTs have been widely researched and developed as biomaterials that can offer high function, performance, and durability in orthopedic applications. However, the use of CNTs as biomaterials must be administered with caution, as the fibrous nanomaterial may be carcinogenic due to its similar size and shape to asbestos. In this review article, we examine the potential clinical application of CNTs in orthopedic surgery. We first provide an overview of biocompatibility and carcinogenicity studies of CNTs with a focus on their effects on the bone, joint, and respiratory system. Furthermore, we introduce CNT-based biomaterials for orthopedic applications that have been reported in the literature, including scaffolds for bone and cartilage regeneration, composites that enhance the performance of biomaterials, CNT coatings, and devices for treating musculoskeletal tumors.We present Surface Evolver evaluations of the difference in energy between face-centred cubic (fcc) and hexagonal close-packed (hcp) foams in the usual idealized model, for liquid fractions ranging from the dry to the wet limit. The difference vanishes in both limits, and favours hcp for all intermediate liquid fractions, as has been proven. The maximum relative energy difference is very small, of the order of 10-5. The asymptotic dependence on liquid fraction is non-analytic in both limits we present explicit expressions in both cases, derived from first principles. They have been obtained from identifying node interactions (dry limit) and contact interactions (wet limit) as the respective sources for energy differences between fcc and hcp. The wet limit is well described by Morse-Witten theory which has proven to be very powerful for the analytic computation of the surface energy of slightly deformed bubbles.Denatured collagen is a key biomarker for various critical diseases such as cancer. Peptide probes with the repetitive (Gly-Pro-Hyp)n sequences have recently been found to selectively target denatured collagen; however, thermal or UV pretreatment is required to drive the peptides into the monomer conformation, which poses a substantial challenge for clinical applications. We herein construct two peptide probes, FAM-GOO and FAM-GPP, consisting of the repetitive (Gly-Hyp-Hyp)8 and (Gly-Pro-Pro)8 sequences, respectively. The CD, fluorescence and colorimetric studies have consistently revealed that FAM-GOO showed strong capability of forming the triple helical structure, while FAM-GPP pronouncedly displayed the single stranded conformation at temperatures as low as 4 °C. The binding experiments have indicated that both peptide probes could recognize denatured collagen with high specificity, and FAM-GPP remarkably did not need the preheating treatment. The tissue staining results have shown that preheated FAM-GOO and unheated FAM-GPP could target denatured collagen in a wide variety of rat frozen and human FFPE tissue sections. Compared with antibodies specific for a certain type of collagen, both FAM-GOO and FAM-GPP act as broad-spectrum probes for the selective detection of denatured collagen of different types and from different species. Importantly, FAM-GPP possessed the unique capability of maintaining the monomer conformation by itself, thus avoiding the potential risks of the thermal or UV pretreatment. This novel peptide probe provides a handy and versatile biosensor for specifically targeting denatured collagen, which has attractive potential in the diagnosis and therapeutics of collagen-involved diseases.The influence of poroelasticity on the contact mechanics of thin polyacrylamide films was investigated with a surface forces apparatus (SFA). A model based on a thin film approximation described compression forces for hydrated gels; polymer scaling theory explained the effects of gel dehydration. The results demonstrate that fluid flow dictates the apparent stiffness of highly confined poroelastic films.Designing antimicrobials with high efficiency and long-term antibacterial activity is an imperative issue. We found that the antimicrobial effect of Ti3C2Tx and Ag/Ti3C2Tx could be significantly strengthened upon near-infrared light exposure. The synergistic antibacterial mode of the photothermal bactericidal effect and intrinsic bacterial activity have been revealed, which confirms that the Ti3C2Tx MXene is an excellent near-infrared light-mediated nanoplatform for antibacterial applications. To further test the antibacterial effect in practical applications, Ag/Ti3C2Tx embedded hydrogels were used as wound dressings in a wound model experiment. They exhibit outstanding bacterial inhibition and wound healing performance with near-infrared light exposure. This work inspires us to explore the MXene-based photothermal platform in terms of antibacterial application.
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