31 research outputs found
Enhanced cellular uptake of aminosilane-coated superparamagnetic iron oxide nanoparticles in mammalian cell lines
Surface molecular tailoring using pH-switchable supramolecular dendron-ligand assemblies
[Image: see text] The rational design of materials with tailored properties is of paramount importance for a wide variety of biological, medical, electronic and optical applications. Here we report molecular level control over the spatial distribution of functional groups on surfaces utilizing self-assembled monolayers (SAMs) of pH-switchable surface-appended pseudorotaxanes. The supramolecular systems were constructed from a poly(aryl ether) dendron-containing a dibenzo[24]crown-8 (DB24C8) macrocycle and a thiol ligand-containing a dibenzylammonium recognition site and a fluorine end group. The dendron establishes the space (dendritic effect) that each pseudorotaxane occupies on the SAM. Following SAM formation, the dendron is released from the surface by switching off the noncovalent interactions upon pH stimulation, generating surface materials with tailored physical and chemical properties
Synthesis of Functional Building Blocks for Type III-B Rotaxane Dendrimer
Second-generation type III-B rotaxane dendrons, equipped with succinimide and acetylene functional groups, were synthesized successfully and characterized by NMR spectroscopy and mass spectrometry. A cell viability study of a dendron with a normal cell line of L929 fibroblast cells revealed no obvious cytotoxicity at a range of 5 to 100 ÎŒM. The nontoxic properties of the sophisticated rotaxane dendron building blocks provided a choice of bio-compatible macromolecular machines that could be potentially developed into polymeric materials
A Fluorescent and Switchable Rotaxane Dual Organocatalyst
Rotaxane organocatalysis
presents a new direction toward controlled
one-pot catalytic reactions. By combining molecular switches and catalysts,
fluorescence and pH-responsive switching along with the exclusive
selectivity of dual catalytic reactions are demonstrated. A newly
designed [2]Ârotaxane catalyst containing an anthracene group was used
to visualize the catalytic reaction process upon switching the macrocycle
Azobenzene dendronized carbon nanoparticles: the effect of light antenna
Fluorescent carbon nanoparticles are grafted with azobenzene dendrons, giving unique dendronized carbon nanoparticles that exhibit an increased quantum yield by as much as [similar]74% at a low concentration. Such an improvement is attributed to the strong light harvesting capability of grafted azobenzene dendrons that act as âlight antennaâ to collect photons and the excitons generated then traverse to adjacent central carbon nanoparticles
Cellular Interactions and Formation of an Epithelial âNanocoating-Like Barrierâ with Mesoporous Silica Nanoparticles
Oral mucosa as the front-line barrier in the mouth is constantly exposed to a complex microenvironment with multitudinous microbes. In this study, the interactions of mesoporous silica nanoparticles (MSNs) with primary human gingival epithelial cells were analyzed for up to 72 h, and their diffusion capacity in the reconstructed human gingival epithelia (RHGE) and porcine ear skin models was further assessed at 24 h. It was found that the synthesized fluorescent mesoporous silica nanoparticles (RITC-NPs) with low cytotoxicity could be uptaken, degraded, and/or excreted by the human gingival epithelial cells. Moreover, the RITC-NPs penetrated into the stratum corneum of RHGE in a time-dependent manner, while they were unable to get across the barrier of stratum corneum in the porcine ear skins. Consequently, the penetration and accumulation of RITC-NPs at the corneum layers of epithelia could form a ânanocoating-like barrierâ. This preliminary proof-of-concept study suggests the feasibility of developing nanoparticle-based antimicrobial and anti-inflammatory agents through topical application for oral healthcare
Red-Emissive Guanylated Polyene-Functionalized Carbon Dots Arm Oral Epithelia against Invasive Fungal Infections
International audienceOral candidiasis as a highly prevalent and recurrent infection in medically compromised individuals is mainly caused by the opportunistic fungal pathogen Candida albicans. This epithelial infection, if not controlled effectively, can progress to life-threatening systemic conditions and complications. The efficacy of current frontline antifungals is limited due to their poor bioavailability and systemic toxicity. As such, an efficient intervention is essential for controlling disease progression and recurrence. Herein, a theranostic nanoplatform (CD-Gu+-AmB) was developed to track the penetration of antifungals and perturb the invasion of C. albicans at oral epithelial tissues, via decorating the homemade red-emissive carbon dots (CD) with positively charged guanidine groups (Gu+) followed by conjugation with antifungal polyene (amphotericin B, AmB) in a reacting site-controllable manner. The generated CD-Gu+-AmB favorably gathered within the Candida cells and exhibited potent antifungal effects in both planktonic and biofilm forms. It selectively accumulated in the nuclei of human oral keratinocytes and exhibited undetectable toxicity to the host cells. Moreover, we reported for the first time the penetration and exfoliation profiles of CD in a three-dimensional organotypic model of human oral epithelial tissues, demonstrating that the extra- and intracellular accumulation of CD-Gu+-AmB effectively resisted the invasion of C. albicans by forming a "shielding" layer throughout the entire tissue. This study establishes a multifunctional CD-based theranostic nanoplatform functioning as a traceable and topically applied antifungal to arm oral epithelia, thereby shedding light on early intervention of mucosal candidiasis for oral and general health
Wearable Safeguarding Leather Composite with Excellent Sensing, Thermal Management, and Electromagnetic Interference Shielding
Abstract This work illustrates a âsoftâtoughnessâ coupling design method to integrate the shear stiffening gel (SSG), natural leather, and nonwoven fabrics (NWF) for preparing leather/MXene/SSG/NWF (LMSN) composite with high antiâimpact protecting, piezoresistive sensing, electromagnetic interference (EMI) shielding, and human thermal management performance. Owing to the porous fiber structure of the leather, the MXene nanosheets can penetrate leather to construct a stable 3D conductive network; thus both the LM and LMSN composites exhibit superior conductivity, high Joule heating temperature, and an efficient EMI shielding effectiveness. Due to the excellent energy absorption of the SSG, the LMSN composites possess a huge forceâbuffering (about 65.5%), superior energy dissipation (above 50%), and a high limit penetration velocity of 91 m sâ1, showing extraordinary antiâimpact performance. Interestingly, LMSN composites possess an unconventional opposite sensing behavior to piezoresistive sensing (resistance reduction) and impact stimulation (resistance growing), thus they can distinguish the low and high energy stimulus. Ultimately, a soft protective vest with thermal management and impact monitoring performance is further fabricated, and it shows a typical wireless impactâsensing performance. This method is expected to have broad application potential in the nextâgeneration wearable electronic devices for human safeguarding