Insights on Luminescent Micro- and Nanospheres of Infinite Coordination Polymers.

Coordination polymers have been extensively studied in recent years. Some of these materials can exhibit several properties such as permanent porosity, high surface area, thermostability and light emission, as well as open sites for chemical functionalization. Concerning the fact that this kind of compounds are usually solids, the size and morphology of the particles are important parameters when an application is desired. Inside this context, there is a subclass of coordination polymers, named infinite coordination polymers (ICPs), which auto-organize as micro- or nanoparticles with low crystallinity. Specifically, the particles exhibiting spherical shapes and reduced sizes can be better dispersed, enter cells much easier than bulk crystals and be converted to inorganic materials by topotactic transformation. Luminescent ICPs, in particular, can find applications in several areas, such as sensing probes, light-emitting devices and bioimaging. In this review, we present the state-of-the-art of ICP-based spherical particles, including the growth mechanisms, some applications for luminescent ICPs and the challenges to overcome in future commercial usage of these materials.

Breast Cancer Targeting of a Drug Delivery System through Postsynthetic Modification of Curcumin@N3-bio-MOF-100 via Click Chemistry.

Metal-organic frameworks (MOFs) offer many opportunities for applications across biology and medicine. Their wide range of chemical composition makes toxicologically acceptable formulation possible, and their high level of functionality enables possible applications as delivery systems for therapeutics agents. Surface modifications have been used in drug delivery systems to minimize their interaction with the bulk, improving their specificity as targeted carriers. Herein, we discuss a strategy to achieve a tumor-targeting drug-loaded MOF using "click" chemistry to anchor functional folic acid (FA) molecules on the surface of N3-bio-MOF-100. Using curcumin (CCM) as an anticancer drug, we observed drug loading encapsulation efficiencies (DLEs) of 24.02 and 25.64% after soaking N3-bio-MOF-100 in CCM solutions for 1 day and 3 days, respectively. The success of postsynthetic modification of FA was confirmed by 1H NMR spectroscopy, Fourier transform infrared spectroscopy (FTIR), and liquid chromatography-mass spectrometry (LC-MS). The stimuli-responsive drug release studies demonstrated an increase of CCM released under acidic microenvironments. Moreover, the cell viability assay was performed on the 4T1 (breast cancer) cell line in the presence of CCM@N3-bio-MOF-100 and CCM@N3-bio-MOF-100/FA carriers to confirm its biological compatibility. In addition, a cellular uptake study was conducted to evaluate the targeting of tumor cells.

Advances in the use of MOFs for Cancer Diagnosis and Treatment: An Overview.

Nanoparticles as drug delivery systems and diagnostic agents have gained much attention in recent years, especially for cancer treatment. Nanocarriers improve the therapeutic efficiency and bioavailability of antitumor drugs, besides providing preferential accumulation at the target site. Among different types of nanocarriers for drug delivery assays, metal-organic frameworks (MOFs) have attracted increasing interest in the academic community. MOFs are an emerging class of coordination polymers constructed of metal nodes or clusters and organic linkers that show the capacity to combine a porous structure with high drug loading through distinct kinds of interactions, overcoming the limitations of traditional drug carriers explored up to date. Despite the rational design and synthesis of MOFs, structural aspects and some applications of these materials like gas adsorption have already been comprehensively described in recent years; it is time to demonstrate their potential applications in biomedicine. In this context, MOFs can be used as drug delivery systems and theranostic platforms due to their ability to release drugs and accommodate imaging agents. This review describes the intrinsic characteristics of nanocarriers used in cancer therapy and highlights the latest advances in MOFs as anticancer drug delivery systems and diagnostic agents.

In Vitro Activity of Copper(II) Complexes, Loaded or Unloaded into a Nanostructured Lipid System, against Mycobacterium tuberculosis.

Tuberculosis (TB) is an infectious disease caused mainly by the bacillus Mycobacterium tuberculosis (Mtb), presenting 9.5 million new cases and 1.5 million deaths in 2014. The aim of this study was to evaluate a nanostructured lipid system (NLS) composed of 10% phase oil (cholesterol), 10% surfactant (soy phosphatidylcholine, sodium oleate), and Eumulgin(®) HRE 40 ([castor oil polyoxyl-40-hydrogenated] in a proportion of 3:6:8), and an 80% aqueous phase (phosphate buffer pH = 7.4) as a tactic to enhance the in vitro anti-Mtb activity of the copper(II) complexes [CuCl2(INH)2]·H2O (1), [Cu(NCS)2(INH)2]·5H2O (2) and [Cu(NCO)2(INH)2]·4H2O (3). The Cu(II) complex-loaded NLS displayed sizes ranging from 169.5 ± 0.7095 to 211.1 ± 0.8963 nm, polydispersity index (PDI) varying from 0.135 ± 0.0130 to 0.236 ± 0.00100, and zeta potential ranging from -0.00690 ± 0.0896 to -8.43 ± 1.63 mV. Rheological analysis showed that the formulations behave as non-Newtonian fluids of the pseudoplastic and viscoelastic type. Antimycobacterial activities of the free complexes and NLS-loaded complexes against Mtb H37Rv ATCC 27294 were evaluated by the REMA methodology, and the selectivity index (SI) was calculated using the cytotoxicity index (IC50) against Vero (ATCC(®) CCL-81), J774A.1 (ATCC(®) TIB-67), and MRC-5 (ATCC(®) CCL-171) cell lines. The data suggest that the incorporation of the complexes into NLS improved the inhibitory action against Mtb by 52-, 27-, and 4.7-fold and the SI values by 173-, 43-, and 7-fold for the compounds 1, 2 and 3, respectively. The incorporation of the complexes 1, 2 and 3 into the NLS also resulted in a significant decrease of toxicity towards an alternative model (Artemia salina L.). These findings suggest that the NLS may be considered as a platform for incorporation of metallic complexes aimed at the treatment of TB.

A Nanostructured Lipid System as a Strategy to Improve the in Vitro Antibacterial Activity of Copper(II) Complexes.

The aim of this study was to construct a nanostructured lipid system as a strategy to improve the in vitro antibacterial activity of copper(II) complexes. New compounds with the general formulae [CuX2(INH)2]·nH2O (X = Cl(-) and n = 1 (1); X = NCS(-) and n = 5 (2); X = NCO(-) and n = 4 (3); INH = isoniazid, a drug widely used to treat tuberculosis) derived from the reaction between the copper(II) chloride and isoniazid in the presence or absence of pseudohalide ions (NCS(-) or NCO(-)) were synthesized and characterized by infrared spectrometry, electronic absorption spectroscopy, electron paramagnetic resonance (EPR) spectroscopy, elemental analysis, melting points and complexometry with 2,2',2'',2'''-(Ethane-1,2-diyldinitrilo)tetraacetic acid (EDTA). The characterization techniques allowed us to confirm the formation of the copper(II) complexes. The Cu(II) complexes were loaded into microemulsion (MEs) composed of 10% phase oil (cholesterol), 10% surfactant [soy oleate and Brij(®) 58 (1:2)] and 80% aqueous phase (phosphate buffer pH = 7.4) prepared by sonication. The Cu(II) complex-loaded MEs displayed sizes ranging from 158.0 ± 1.060 to 212.6 ± 1.539 nm, whereas the polydispersity index (PDI) ranged from 0.218 ± 0.007 to 0.284 ± 0.034. The antibacterial activity of the free compounds and those that were loaded into the MEs against Staphylococcus aureus ATCC(®) 25923 and Escherichia coli ATCC(®) 25922, as evaluated by a microdilution technique, and the cytotoxicity index (IC50) against the Vero cell line (ATCC(®) CCL-81(TM)) were used to calculate the selectivity index (SI). Among the free compounds, only compound 2 (MIC 500 µg/mL) showed activity for S. aureus. After loading the compounds into the MEs, the antibacterial activity of compounds 1, 2 and 3 was significantly increased against E. coli (MIC's 125, 125 and 500 µg/mL, respectively) and S. aureus (MICs 250, 500 and 125 µg/mL, respectively). The loaded compounds were less toxic against the Vero cell line, especially compound 1 (IC50 from 109.5 to 319.3 µg/mL). The compound 2- and 3-loaded MEs displayed the best SI for E. coli and S. aureus, respectively. These results indicated that the Cu(II) complex-loaded MEs were considerably more selective than the free compounds, in some cases, up to 40 times higher.