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Petterson Davidsen posted an update 3 months, 1 week ago
It remains a great challenge to integrate effective photothermal therapeutic materials with upconversion nanoparticles (UCNPs) into one structure with small size. Herein, a new and simple method was developed to combine the luminescent UCNPs with vanadium disulfide (VS2) heterogeneously growing on the UCNPs. VS2 was grown directly on the surface of UCNPs to obtain oil-soluble nanocomposites, UCNPs@VS2. Then polyethylene glycol (mPEG) was functionalized on the surface of the nanocomposites to improve the water solubility, resulting in the integrated nanostructure UCNPs@VS2-mPEG (with an approximate size of 25 nm) for bioimaging and photothermal therapy in vitro. Importantly, cytotoxicity test results show that the final nanostructure has good biocompatibility. Furthermore, due to the excellent photothermal effects of VS2 and the unique imaging function of UCNPs, the nanostructure shows effective photothermal therapy for HeLa cells and was successfully applied in magnetic resonance imaging and upconversion luminescence imaging in vitro. Therefore, this study demonstrates a simple yet powerful method of growing VS2 on the surface of UCNPs, which provides an effective method to establish one integrated nanostructure with a nanoscale advantage for dual-model bioimaging and treatment.Mucosal tissues constitute the largest interface between the body and the surrounding environment and they regulate the access of molecules, supramolecular structures, particulate matter, and pathogens into it. All mucosae are characterized by an outer mucus layer that protects the underlying cells from physicochemical, biological and mechanical insults, a mono-layered or stratified epithelium that forms tight junctions and controls the selective transport of solutes across it and associated lymphoid tissues that play a sentinel role. Mucus is a gel-like material comprised mainly of the glycoprotein mucin and water and it displays both hydrophilic and hydrophobic domains, a net negative charge, and high porosity and pore interconnectivity, providing an efficient barrier for the absorption of therapeutic agents. click here To prolong the residence time, absorption and bioavailability of a broad spectrum of active compounds upon mucosal administration, mucus-penetrating and mucoadhesive particles have been designed by tunlial barrier, the mucosal-associated lymphatic tissues and microbiota. Then, the most relevant investigations attempting to identify and validate the key particle features that govern nanomaterial-mucosa interactions and that are relevant in both nanomedicine and nanotoxicology are discussed in a holistic manner. Finally, the most popular experimental techniques and the incipient use of mathematical and computational models to characterize these interactions are described.One of the challenges of self-assembling finite-sized colloidal aggregates with a sought morphology is the necessity of precisely sorting the position of the colloids at the microscopic scale to avoid the formation of off-target structures. Microfluidic platforms address this problem by loading into single droplets the exact amount of colloids entering the targeted aggregate. Using theory and simulations, in this paper, we validate a more versatile design allowing us to fabricate different types of finite-sized aggregates, including colloidal molecules or core-shell clusters, starting from finite density suspensions of isotropic colloids in bulk. In our model, interactions between particles are mediated by DNA linkers with mobile tethering points, as found in experiments using DNA oligomers tagged with hydrophobic complexes immersed into supported bilayers. By fine-tuning the strength and number of the different types of linkers, we prove the possibility of controlling the morphology of the aggregates, in particular, the valency of the molecules and the size of the core-shell clusters. In general, our design shows how multivalent interactions can lead to microphase separation under equilibrium conditions.Single molecules can now be visualised with unprecedented precision. As the resolution of single-molecule experiments improves, so too does the breadth, quantity and quality of information that can be extracted using these methodologies. In the field of DNA nanotechnology, we use programmable interactions between nucleic acids to generate complex, multidimensional structures. We can use single-molecule techniques – ranging from electron and fluorescence microscopies to electrical and force spectroscopies – to report on the structure, morphology, robustness, sample heterogeneity and other properties of these DNA nanoconstructs. In this Tutorial Review, we will detail how complementarity between static and dynamic single-molecule techniques can provide a unified image of DNA nanoarchitectures. The single-molecule methods that we discuss provide unprecedented insight into chemical and structural behaviour, yielding not just an average outcome but reporting on the distribution of values, ultimately showing how bulk properties arise from the collective behaviour of individual structures. As the fields of both DNA nanotechnology and single-molecule characterisation intertwine, a feedback loop is generated between disciplines, providing new opportunities for the development and operation of DNA-based materials as sensors, delivery vehicles, machinery and structural scaffolds.Lipid asymmetry is a crucial property of biological membranes and significantly influences their physical and mechanical properties. It is responsible for maintaining different chemical environments on the external and internal surfaces of cells and organelles and plays a vital role in many biological processes such as cell signalling and budding. In this work we show, using non-equilibrium molecular dynamics (NEMD) simulations, that thermal fields can induce lipid asymmetry in biological membranes. We focus our investigation on cholesterol, an abundant lipid in the plasma membrane, with a rapid flip-flop rate, significantly influencing membrane properties. We demonstrate that thermal fields induce membrane asymmetry with cholesterol showing thermophobic behaviour and therefore accumulating on the cold side of the membrane. This work highlights a possible experimental route to preparing and controlling asymmetry in synthetic membranes.