Nanoparticles with a diameter of o100 nm are regarded as potential medical materials, as this size allows nanoparticles to circulate in vivo and possibly reach targeted tumors. Inorganic nanoparticles in particular are able to interact with light and/or magnetic fields, thus extending their potential applications to such fields as fluorescence labeling, magnetic resonance imaging and stimulus-responsive drug delivery that are essential to the diagnosis and treatment of disease. To facilitate their use in such applications, the appropriate design of surface ligands on these nanoparticles is necessary. The surface ligands determine the physicochemical properties of the surface, such as hydrophilicity/hydrophobicity and zeta potential as well as dispersibility in solution. These properties have an especially important role in determining nanoparticle-cell associations, such as cellular membrane permeability, immune responses and localization in vivo. This review focuses on recent advances in the surface engineering of nanoparticles for therapeutic applications.

We demonstrate that binary mixtures of small and large gold nanoparticles (GNPs) (5/15, 5/30, 10/30, and 15/30 nm in diameter) in the presence of a glucose-terminated fluorinated oligo(ethylene glycol) ligand can spontaneously form size-segregated assemblies. The outermost layer of the assembly is composed of a single layer of small-sized GNPs, while the larger-sized GNPs are located in the interior, forming what is referred to as a yolk/shell assembly. Time course study reveals that small and large GNPs aggregate together, and these kinetically trapped aggregations were transformed into a size-segregated structure by repeating fusions. A yolk/shell structure was directly visualized in solution by X-ray laser diffraction imaging, indicating that the structure was truly formed in solution, but not through a drying process.

Gold nanoparticles (GNPs) show promise as both drug and imaging carriers with applications in both diagnosis and therapy. For the safe and effective use of such gold nanomaterials in the biomedical field, it is crucial to understand how the size and shape of the nanomaterials affect their biological features, such as in vitro cellular uptake speed and accumulation as well as cytotoxicity. Herein, we focus on triangular gold nanoparticles (TNPs) of four different sizes (side length 46, 55, 72, and 94 nm; thickness 30 nm) and compare the cellular internalization efficiency with those of spherical nanoparticles (SNPs) of various diameters (22, 39, and 66 nm). Both surfaces were coated with anionic thiol ligands. Inductively coupled plasma-emission spectrometry (ICP-ES) data demonstrated that TNPs with longer sides showed higher levels of uptake into RAW264.7 and HeLa cells. On the other hand, in the case of SNPs, those with smaller diameters showed higher levels of uptake in both cells. Our results support the notion of a reverse size dependence of TNPs and SNPs in terms of cellular uptake. For HeLa cells, in particular, 20-fold more efficient internalization was observed for TNPs with longer sides (72 nm side length) compared to SNPs (66 nm) with a similar surface area. These results highlight the importance of the shape of nanomaterials on their interactions with cells and provide a useful guideline for the use of TNPs.

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A series of novel D-glucose-derived 1,2,3-triazoles have been synthesized in excellent yields via Cu(I)-catalyzed 1,3-dipolar cycloaddition by using methyl a-Dglucopyranoside as starting material. All the new compounds were confirmed by 1 H NMR, 13 C NMR, IR, MS, and HRMS spectra, and their antimicrobial activities were screened against Gram-Positive, Gram-Negative bacteria, and fungi. Bioactive assay manifested that some of the synthesized glucose-derived 1,2,3-triazoles exhibited good antibacterial and antifungal activities. Notably, compound 5k gave the most potent efficiency with MIC 50 value of 6 lM against Candida albicans, which was nine-fold more active than the reference drug Fluconazole. It also exhibited good antibacterial activity against Escherichia coli with the MIC 50 value of 10.8 lM compared to Chloramphenicol while the corresponding hydrochloride 4k revealed remarkable inhibitory against Bacillus subtilis with an MIC 50 value of 11 lM.