IRMOF-3: A fluorescent nanoscale metal organic frameworks for selective sensing of glucose and Fe (III) ions without any modification.

The amine functionalized isoreticular metal-organic framework-3 (IRMOF-3) is synthesized by hydrothermal method. Till now, it's widely used in the area of gas separation, adsorption, and catalysis due to large surface area, structural stability, and tunability. Here, we have reported the use of fluorescent nanoscale IRMOF-3 for highly selective detection of glucose as well as Fe3+ ions without any modification. This is due to NH2 and COOH groups are present on the surface of IRMOF-3 to bind cis-diols of the glucose molecule via host-guest interaction, and Fe3+ ions via ligand to metal charge transfer. The Synthesized IRMOF-3 has average diameter of 160 ±â€¯20 nm and interestingly possess deep blue fluorescent emission spectra at 460 nm with quantum yield 17.3%. Using fluorometric assay, the limit of detection (LOD) of glucose and Fe3+ ions was found to be 0.56 µM and 4.2 nM respectively. More importantly, the synthesized IRMOF-3 is also utilized for detection of glucose and Fe3+ ions in bio-environmental samples.

One pot synthesis of carbon dots decorated carboxymethyl cellulose- hydroxyapatite nanocomposite for drug delivery, tissue engineering and Fe3+ ion sensing.

In this work, carbon dots conjugated carboxymethyl cellulose-hydroxyapatite nanocomposite has been synthesized by one-pot synthesis method and used for multiple applications like metal ion sensing, osteogenic activity, bio-imaging and drug carrier. The structure and morphology of the nanocomposite were systematically characterized by FTIR, XRD, TGA, FESEM, TEM and DLS. Results clearly demonstrated the formation of fluorescent enabled carbon dots conjugated nanocomposite from carboxymethyl cellulose-hydroxyapatite nanocomposite by a simple thermal treatment. The synthesized nanocomposite is smaller than 100 nm and exhibits fluorescence emission band around 440 nm upon excitation with 340 nm wavelength. In the meantime, the nanocomposite was loaded with a chemotherapeutic drug, doxorubicin to evaluate the drug loading potential of synthesized nanocomposite. Moreover, the as-synthesized nanocomposite showed good osteogenic properties for bone tissue engineering and also exhibited excellent selectivity and sensitivity towards Fe3+ ions.

Fabrication of nitrogen- and phosphorous-doped carbon dots by the pyrolysis method for iodide and iron(III) sensing.

A facile and novel strategy to synthesize nitrogen- and phosphorous-doped carbon dots (NPCDs) by single step pyrolysis method is described here. Citric acid is used as carbon source and di-ammonium hydrogen phosphate is used as both nitrogen and phosphorous sources, respectively. Through the extensive study on optical properties, morphology and chemical structures of the synthesized NPCDs, it is found that as-synthesized NPCDs exhibited good excitation-dependent luminescence property, spherical morphology and high stability. The obtained NPCDs are stable in aqueous medium and possess a quantum yield of 10.58%. In this work, a new assay method is developed to detect iodide ions using the synthesized NPCDs. Here, the inner filter effect is applied to detect the iodide ion and exhibited a wide linear response concentration range (10-60 µM) with a limit of detection (LOD) of 0.32 µM. Furthermore, the synthesized NPCDs are used for the selective detection of iron(III) (Fe3+ ) ions and cell imaging. Fe3+ ions sensing assay shows a detection range from 0.2 to 30 µM with a LOD of 72 nM. As an efficient photoluminescence sensor, the developed NPCDs have an excellent biocompatibility and low cytotoxicity, allowing Fe3+ ion detection in HeLa cells.

One-pot synthesis of multifunctional nanoscale metal-organic frameworks as an effective antibacterial agent against multidrug-resistant Staphylococcus aureus.

Drug-resistant bacteria are an increasingly serious threat to global public health. In particular, infections from multidrug-resistant (MDR) Gram-positive bacteria (i.e. Staphylococcus aureus) are growing global health concerns. In this work, we report the first use of nanoscale metal-organic frameworks (NMOFs) coencapsulating an antibiotic (vancomycin) and targeting ligand (folic acid) in one pot to enhance therapeutic efficacy against MDR S. aureus. Zeolitic imidazolate framework (ZIF-8) NMOFs, which have globular morphologies coencapsulating vancomycin and folic acid, are characterized by transmission electron microscopy, field-emission scanning electron microscopy, powder x-ray diffraction, ulltraviolet-visible spectroscopy, and dynamic light-scattering techniques. We determined that the presence of folic acid on the surface of the NMOFs is significant in the sense of effective uptake by MDR S. aureus through endocytosis. The functionalized NMOFs transport vancomycin across the cell wall of MDR S. aureus and enhance antibacterial activity, which has been confirmed from studies of the minimum inhibitory concentration, minimum bactericidal concentration, cytotoxicity of bacterial cells, and generation of reactive oxygen species. This work shows that functionalized NMOFs hold great promise for effective treatment of MDR S. aureus.

Nanostructured Fe3O4@Fe2O3/Carbon Dots Heterojunction for Efficient Photocatalyst Under Visible Light.

A facile method for the synthesis of porous magnetic nanoparticles (Fe3O4@Fe2O3) embedded with carbon dots (CDs) are demonstrated for photocatalysis study. Here, a simple, low-cost and green method is developed to synthesize CDs from natural source. The synthesized carbon dots are highly water soluble and monodisperse with particle size 2­5 nm. X-ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM), transmission electron microscopy (TEM), Fourier transform infrared spectroscopy (FTIR), Raman spectroscopy, UV-Vis absorption spectroscopy, BET surface area were employed to investigate the crystal structure, morphology, surface groups, optical properties, surface area of the synthesized nanocomposites. The photocatalytic performance of the nanocomposites was analyzed for the degradation of methylene blue under visible light and exhibited higher photocatalytic activity compared to Fe2O3 nanoparticles. Here the crucial role of CDs has been illustrated for the enhancement of photocatalytic activity.

One-pot synthesis of folic acid encapsulated upconversion nanoscale metal organic frameworks for targeting, imaging and pH responsive drug release.

In this work, a new theranostic nanoplatform is developed to construct an anticancer drug carrier by integrating the distinct advantages of upconversion nanoparticles (UCNPs) and metal organic frameworks (MOFs) encapsulated with a targeting ligand. Here NaYF4:Yb3+,Er3+ is chosen as an upconversion nanoparticle for its high luminescence properties. Then, folic acid encapsulated Zeolitic Imidazolate Framework-8 (ZIF-8) is directly coated on UCNPs in one step to form a monodispersed core-shell structured nanocomposite (labeled as UCNPs@ZIF-8/FA). The synthesized upconversion nanoscale MOFs (NMOFs) are simultaneously used as a targeted anticancer drug carrier and in cellular imaging. The UCNP@ZIF-8/FA nanocomposites are found to be nontoxic towards the human cervix adenocarcinoma (HeLa) and mouse fibroblast (L929) cell lines via a cell viability assay. It is worthwhile noting that, the anticancer drug 5-fluorouracil (5-FU) is absorbed into UCNP@ZIF-8/FA nanocomposites (loading amount 685 mg g-1) and also pH responsive drug release is observed. The as-prepared 5-FU loaded UCNP@ZIF-8/FA nanocomposites exhibited greater cytotoxicity towards HeLa cells due to the folate receptor-mediated endocytosis. Our study highlights the potential of developing multifunctional upconversion NMOFs for simultaneous targeted cellular imaging with delivery of anticancer drugs.

Carbon Dots Embedded Magnetic Nanoparticles @Chitosan @Metal Organic Framework as a Nanoprobe for pH Sensitive Targeted Anticancer Drug Delivery.

Recently, nanoscale metal organic frameworks (NMOFs) have been demonstrated as a promising carrier for drug delivery, as they possess many advantages like large surface area, high porosity, and tunable functionality. However, there are no reports about the functionalization of NMOFs, which combines cancer-targeted drug delivery/imaging, magnetic property, high drug loading content, and pH-sensitive drug release into one system. Existing formulations for integrating target molecules into NMOF are based on multistep synthetic processes. However, in this study, we report an approach that combines NMOF (IRMOF-3) synthesis and target molecule (Folic acid) encapsulation on the surface of chitosan modified magnetic nanoparticles in a single step. A noticeable feature of chitosan is control and pH responsive drug release for several days. More importantly, doxorubicin (DOX) was incorporated into magnetic NMOF formulation and showed high drug loading (1.63 g DOX g(-1) magnetic NMOFs). To demonstrate the optical imaging, carbon dots (CDs) are encapsulated into the synthesized magnetic NMOF, thereby endowing fluorescence features to the nanoparticles. These folate targeted magnetic NMOF possess more specific cellular internalization toward folate-overexpressed cancer (HeLa) cells in comparison to normal (L929) cells.

Chitosan conjugated chloroquine: proficient to protect the induction of liver apoptosis during malaria.

Chitosan has impelled continuous motion by its unique physicochemical and biological characteristics. In our study, chitosan-tripolyphosphate (CS-TPP) particles was conjugated with an undervalued antimalarial drug, chloroquine to find out the proficiency against ROS mediated caspase activation and apoptosis in liver during Plasmodium berghei NK65 infection. The transmission electron microscopic image illustrated the size range of particle was less than 50 nm and the particle showed the blood compatibility. ROS generation, mitochondrial membrane potential, anti apoptotic and pro apoptotic protein level of CS-TPP conjugated chloroquine treated group revealed that CS-TPP conjugation amplified the protective capability of chloroquine. FACS study by annexin v-FITC and PI staining reveals chloroquine treatment reduces significantly (P<0.05) the apoptotic cells by 25.31%; whereas chitosan-tripolyphosphate conjugated nanochloroquine decreases by 61.56% apoptotic cell against P. berghei induced liver apoptosis. This study suggests that proficiency of conventional antimalarial drug may escalate by delivery with chitosan nanoparticles to portray defense possessions against malarial damage.