Biomedical Applications of Nanomaterials: Nanotubes and Metal-Organic Frameworks (MOFs)

Nanomedicine plays an important role in the diagnosis, treatment, monitoring and control of biological systems in the area of nanotechnology and has been referred by the National Institute of Health (NIH) as an emergent way of medicine. Nanoparticles are new delivery vehicles with the ability to release drugs to a specific cell type or tissue, which may also improve the pharmacological activity of those drugs by controlling their release, as well as prolonging their short half-lives in blood. The aim of this review is to gather several options of MOFs and nanotubes synthesised with different nanoparticles and processes, some including compound loading and release studies, with particular focus on 13 anti-cancer compounds e.g. doxorubicin, curcumin, methotrexate, etc.; 3 anti-inflammatory compounds, namely ibuprofen, salicylic acid and chlorogenic acid; and with 5 miscellaneous bioactive compounds, including rifampicin, griseofulvin, enoxacin, etc. Finally, other biomedical applications for these composites are shown, like being enzyme immobilisation agents, for water treatment e.g. in swimming pools, and other becoming support to carry & secure integrity of drugs

Room-temperature synthesis of nanometric and luminescent silver-MOFs

Three silver-MOFs were prepared using an optimized, room-temperature methodology starting from AgNO₃ and dicarboxylate ligands in water/ethanol yielding Ag2BDC, Ag2NDC (UAM-1), and Ag2TDC (UAM-2) at 38%–48% (BDC, benzenedicarboxylate; NDC, 1,8-naphthalene-dicarboxylate; TDC, p-terphenyl-4,4″-dicarboxylate). They were characterized by PXRD/FT-IR/TGA/photoluminescence spectroscopy, and the former two by SEM. These materials started decomposing at 330°C, while showing stability. The crystal structure of UAM-1 was determined by PXRD, DFT calculations, and Rietveld refinement. In general, the structure was 3D, with the largest Ag-O bond interlinking 2D layers. The FT-IR spectra revealed 1450 and 1680 bands (cm−1) of asymmetrically stretching aniso-/iso-bidentate -COO in coordination with 2/3-Ag atoms, accompanied by Ag-O bands at 780–740 cm−1, all demonstrating the network formation. XRD and SEM showed nanometric-scale crystals in Ag₂BDC, and UAM-1 developed micrometric single-stranded/agglomerated fibrillar particles of varying nanometric widths. Luminescence spectroscopy showed emission by Ag₂BDC, which was attributed to ligand-to-metal or ligand-to-metal–metal transitions, suggesting energy transfer due to the short distance between adjacent BDC molecules. UAM-1 and UAM-2 did not show luminescence emission attributable to ligand-to-metal transition; rather, they presented only UV emission. The stabilities of Ag₂BDC and UAM-1 were evaluated in PBS/DMEM/DMEM+FBS media by XRD, which showed that they lost their crystallinity, resulting in AgCl due to soft–soft (Pearson’s principle) affinity