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We present the preparation of self-assembled monolayers (SAMs) of pH responsive chiral periodic mesoporous organosilicas (PMOs) as model implants with drug delivery ability. SAMs of pH responsive PMOs were prepared by layer-by-layer coating of PMOs with polyelectrolytes (e.g. the enantiomers of a polycation biopolymer), for delivering organic molecules and anticancer drug molecules locally in a controlled manner to the adhered cells. We demonstrate that the amount of primary fibroblast, immortal NIH 3T3, and malignant Colo 818 cells adhered to the SAM of the d-enantiomer of polycation-functionalized PMOs was higher in comparison to that of the l-enantiomer of the polycation-functionalized PMO monolayer. In addition, we observe that the 3T3 and Colo cells internalized more of the organic and anticancer drug molecules (released from pH responsive PMOs) than the primary cells did due to the local acidic environment of them. Therefore, as the chirality of the PMOs influenced the amount of cells that adhered, the released molecules interacted with different amounts of cells which allowed us to tune the extent of local drug delivery.Every biosensor, bioengineered scaffold or biomedical implant depends crucially on an ability to control protein adsorption at the material surface. Yet the adsorption of proteins to solid surfaces in aqueous media is a complex and poorly understood phenomenon. To gain further insights we study protein adsorption using the quartz crystal microbalance for 10 model globular proteins interacting with positive, negative, neutral, hydrophobic and mixed alkanethiol monolayers as well as silica, polystyrene and Teflon, equating to approximately 200 protein-surface combinations. The charge state of the materials in liquid was measured with atomic force microscopy using a colloidal probe and numerically solving the full non-linear Poisson-Boltzmann equation. This approach has allowed us to address some of the important questions surrounding the basic principles that govern protein adsorption including the relative importance of net charge and hydrophobicity and why some materials are protein resistant. With our set of mixed monolayer surfaces, we can modulate charge over a wide range whilst eliminating hydrophobic interactions and vice versa- thus permitting determination of the functional dependence of adsorption on these parameters. This has led us to develop two empirical predictive models with up to 90% accuracy that together encompass most materials relevant to biotechnological and biomedical applications.Uniform and porous CoNi2Se4 was successfully synthesized by electrodeposition onto a composite electrode comprising reduced graphene oxide (rGO) anchored on a Ni foam substrate (prepared hydrothermally). This CoNi2Se4-rGO@NF composite electrode has been employed as an electrocatalyst for the direct oxidation of glucose, thereby acting as a high-performance non-enzymatic glucose sensor. Direct electrochemical measurement with the as-prepared electrode in 0.1 M NaOH revealed that the CoNi2Se4-rGO nanocomposite has excellent electrocatalytic activity towards glucose oxidation in an alkaline medium with a sensitivity of 18.89 mA mM-1 cm-2 and a wide linear response from 1 μM to 4.0 mM at a low applied potential of +0.35 V vs. Ag|AgCl. This study also highlights the effect of decreasing the anion electronegativity on enhancing the electrocatalytic efficiency by lowering the potential needed for glucose oxidation. The catalyst composite also exhibits high selectivity towards glucose oxidation in the presence of several interferents normally found in physiological blood samples. A low glucose detection limit of 0.65 μM and long-term stability along with a short response time of approximately 4 seconds highlights the promising performance of the CoNi2Se4-rGO@NF electrode for non-enzymatic glucose sensing with high precision and reliability.Transdermal delivery of diclofenac sodium (DS) has drawn much attention for the advantages of avoiding first-pass metabolism, reduced systemic toxicity and better patient compliance, but the successful translation of reported transdermal drug delivery systems (TDDSs) is still limited by poor skin permeability and uncontrollable drug release. Herein, we designed and fabricated a novel ultrasound responsive TDDS by embedding DS-loaded polyester microcapsules into a hydrogel patch based on four-armed poly(ethylene glycol). selleck inhibitor The rational design endows the microcapsule-embedded hydrogel patch with good biocompatibility, excellent skin-adhesion properties and well-controlled ultrasound responsive release behavior. More importantly, by employing ultrasound as a simultaneous trigger of drug release and efficient penetration enhancer, the encapsulated drug could be released and pass through the skin barrier rapidly under ultrasound, while without the action of ultrasound, a negligible amount of drug was released and penetrated into the subcutaneous tissues in ex vivo and in vivo transdermal drug release experiments, indicating that improved and controllable transdermal delivery of DS was achieved. Our work demonstrated that the microcapsule-embedded hydrogel patch may be a promising candidate as an ultrasound responsive and enhanced TDDS of DS for treating diseases such as arthritis and topical soft tissue injuries.In this study, in situ sulfur-doped carbon nitride nanosheets (S-g-C3N4 NSs) are used as the signal readout for the sensitive and selective sensing of l-cysteine (l-Cys) in human serum samples based on the competitive coordination chemistry of Cu2+ between l-Cys and S-g-C3N4 NSs. S-g-C3N4 NSs are prepared by using trithiocyanuric acid as a precursor for the first time, which exhibits stronger electrogenerated chemiluminescence (ECL) intensity compared with pristine graphitic carbon nitride nanosheets (g-C3N4 NSs). The ECL signals of the S-g-C3N4 NSs can be quenched by Cu2+ and the subsequent presence of l-Cys can recover the ECL signals of the S-g-C3N4 NSs. These changes are ascribed to the higher coordination ability between Cu2+ and l-Cys than that between Cu2+ and the S-g-C3N4 NSs. On the basis of this, the concentration of l-Cys can be quantitatively determined. Under optimized conditions, the ECL intensity recovery shows a linear relationship with the l-Cys concentration range from 30 nM to 0.2 mM with a lower detection limit of 5 nM (S/N = 3).
Website: https://www.selleckchem.com/products/sn-001.html
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