ß-Cyclodextrin-folate functionalized poly(lactic-co-glycolide)-superparamagnetic ytterbium ferrite hybrid nanocarrier for targeted delivery of camptothecin.

Biocompatible polymer-coated magnetic nanoparticles are designed with an objective to sharp-shoot cancer by loading anticancer drugs on them and delivering to the target site. In this work, novel biocompatible polymers of poly(dl-lactic-co-glycolide), functionalized with ß-cyclodextrin and ß-cyclodextrin-folate conjugate are synthesized and characterized by spectroscopic techniques. Magnetic ytterbium ferrite nanoparticles are prepared, and the synthesized polymers are coated on them. The polymer-coated nanoparticles are intended to be employed as magnetic nanocarriers that transport the anticancer drug, camptothecin. The ferrite nanoparticles are superparamagnetic in nature. Camptothecin was loaded in the nanocarriers and the adsorption percentage was near or above 90%. Study of the in vitro release of camptothecin from the nanocarrier reveals its sustained nature, i.e. a cumulative release of about 50% at 72 h and a pH of 7.4. A pH-dependent enhanced release of 60% is observed, i.e. at a more acidic pH of 6.8. In vitro anti-cancer studies on breast cancer cell lines (MCF7) were carried out. The cell inhibition is enhanced in the case of camptothecin-loaded nanocarrier. The enhanced efficacy of the camptothecin, its sustained release, and the size of the nanocarrier in the range that is considered suitable for magnetic field-assisted drug delivery reveal the magnetic nanocarrier promising for transport of the drug.

Unusual Fluorescence Quenching-Based Al3+ Sensing by an Imidazolylpiperazine Derivative. ß-Cyclodextrin Encapsulation-Assisted Augmented Sensing.

We report in this paper an unusual ß-cyclodextrin mediated-aluminum (III) ion sensing based on augmented quenching of fluorescence. The fluorescent sensing of metal ions by a new ligand prepared (L = 4-[{4-(1H-imidazol-1-yl)phenyl]imino}methyl]piperazine-1-carboxaldehyde) has been investigated as well as the effect of the supramolecular complex formation with ß-CD. In aqueous solution, L shows an increase of fluorescence due to the interaction with ß-cyclodextrin with a formation constant of 77 (± 12) M-1. The ROESY NMR spectrum clearly indicates that L is encapsulated by ß-CD. Theoretical calculations show the possible structure both of the L-ß-CD adduct and of the coordination mode of Al3+ ion to L. In the presence of ß-CD, the piperazine adopts a distorted conformation. It leads to an enhanced Al3+ sensing by the compound in its supramolecular complexed form. The lower limit of detection of Al3+ ions is 6.00 × 10-8 mol L-1. This detection limit slightly expands for L in the presence of ß-CD.

Simple and highly electron deficient Schiff-base host for anions: First turn-on colorimetric bifluoride sensor.

Here in, we have designed, synthesized and isolated sensor L, as a turn-on colorimetric chemo sensor for bifluoride ion. The acetonitrile solution contains L with tetrabutyl ammonium salts of bifluoride, cyanide and fluoride results sudden color changes from yellow to dark brown where as there is no color change observed with any other anionic guests with L. Solution state binding studies of L are carried out by UV-Vis spectrometry titration and the strengths of the chemosensor L towards bifluoride, cyanide and fluoride bindings are found to be 2.67 × 105 M-1, 4.78 × 105 M-1, 4.45 × 105 M-1 respectively. The strength and sensitivity of the absorbance based assay with L for bifluoride ion, are found to be 2.67 × 105 M-1 and 0.7 µM respectively, which is the best (highest binding constant and lowest LOD) ever reported in the literature. In order to use this sensor in practical application, we also prepared a cassette which is fabricated with sensor L and we succeeded to sense bifluoride ion.

Differential Metal Ion Sensing by an Antipyrine Derivative in Aqueous and ß-Cyclodextrin Media: Selectivity Tuning by ß-Cyclodextrin.

ß-Cyclodextrin (ß-CD) is a nontoxic cyclic oligosachcharide that can encapsulate all or part of organic molecules of appropriate size and specific shape through noncovalent interaction. Herein, we report the influence of ß-CD complex formation of an antipyrine derivative on its metal ion sensing behavior. In aqueous solution, the antipyrine shows a turn-on fluorescence sensing of vanadyl ion, and in cyclodextrin medium it senses aluminum ion. The compound shows an unusual fluorescence quenching on binding with ß-cyclodextrin (log KSV = 2.34 ± 0.02). The differential metal ion sensing is due to the partial blocking of the chelating moiety by the cyclodextrin molecule. The structure of the antipyrine-cyclodextrin complex is optimized by two-dimensional rotating-frame Overhauser effect spectroscopy. The binding constant is determined by isothermal titration calorimetry (log K = 2.09 ± 0.004). The metal ion binding site is optimized by quanutm mechanical calculations. The lower limit of detection of vanadyl and aluminum ions, respectively, are 5 × 10-8 and 5 × 10-7 mol dm-3. This is the first report of selectivity of two different cations by a chemosensor in water and in ß-CD.

Molecular encapsulator-appended poly(vinyl alcohol) shroud on ferrite nanoparticles. Augmented cancer-drug loading and anticancer property.

Magnetic nanoparticles (MNPs) have the potency to deliver cancer drugs assisted by the application of a magnetic field. In this paper, we present the design of magnesium ferrite nanoparticles of size suitable for drug delivery. A coating polymer, poly(vinyl alcohol), tethered with a tapered cone-shaped cyclic oligosachcharide, ß-cyclodextrin (ß-CD) is synthesized and used to wrap and disperse the MNPs. The magnetic properties are explored using vibrating sample magnetometry and Mössbauer spectroscopy. The ∑130 nm MNPs, shrouded with the PVA-CD conjugate allows a high amount of the cancer drug, camptothecin, to be loaded on the nanocarrier. Cytotoxicity studies reveal that the loaded drug retains its potency against HEK 293 cells and the cells are sensitive to the treatment by the drug-loaded nanocarrier.

Folate-molecular encapsulator-tethered biocompatible polymer grafted with magnetic nanoparticles for augmented drug delivery.

Magnetic ferrite nanoparticles (MNPs) coated with biocompatible polymers capable of drug loading and release are fascinating nanostructures for delivering anti-cancer drugs. Herein, we report the synthesis and characterization of a novel ß-cyclodextrin-folate-tethered dextran polymer. Nickel-zinc ferrite nanoparticles are prepared and coated with the polymer to form a biocompatible hybrid magnetic nanocarrier. To establish the significance of folate unit of the polymer in anticancer activity, a similar derivatized polymer, i.e. ß-cyclodextrin-dextran conjugate without folate tether is used for comparison. The size of the hybrid MNPs is ∼20 nm, which is a size suitable for cancer drug targeting. The polymer-coated magnetic nanocarriers are soft ferromagnets as suggested by their narrow magnetic hysteresis loops. The anticancer drug camptothecin (CPT) is loaded on the magnetic nanocarriers. The drug loading efficiency is observed to be above 92%. The nanocarriers show sustained in vitro drug release for above 45 h. The in vitro cytotoxicity studies reveal that the loaded CPT retains its potency in the nanocarrier and the folate-tethered nanocarrier shows better anticancer activity than the one which does not carry a folate unit. The magnetic nanocarrier is suitable for magnetic field-guided drug transport, enhanced drug loading and release and folate receptor-mediated endocytotic uptake of drugs by cancer cells.

Molecular encapsulator on the surface of magnetic nanoparticles. Controlled drug release from calcium Ferrite/Cyclodextrin-tethered polymer hybrid.

Magnetic nanoparticles (MNPs) are intriguing due to their potency to deliver anti-cancer drugs. This paper presents the inference from our experimental attempts to add merit to the concept of magnetic drug carrier, by designing calcium ferrite nanoparticles and coating them with a biocompatible dextran tethered with a hydrophobic cavity-containing molecule, ß-cyclodextrin (ß-CD). The size, crystal system, and the morphology of the MNPs are studied. The magnetic properties are explored using vibrating sample magnetometry, SQUID and Mössbauer spectroscopy. The roughly 75nm MNPs, encapsulated with the ß-CD-dextran conjugate allows a slow and sustained in vitro release of the loaded anti-cancer drug, Camptothecin, from the polymer shell. The study of cytotoxicity reveals that the loaded Camptothecin retains its potency as efficient as an effective carrier of the anti-cancer drug. Further, the toxicity of the nanomaterial is tested on an organism which is highly sensitive to toxicity i.e., brine shrimp (Artemia salina). The polymer coating brings down the toxicity of the MNPs.

A simply synthesized biphenyl substituted piperidin-4-one for the fluorescence chemosensing of Cd2.

Ion-induced change in fluorescence is a straight-forward method for detection of toxic metal ions showing immediate response. Cadmium ions are toxic to the environment. We report in this paper a piperidine-4-one-based fluorescent chemosensor of Cd2+ ions, designed and synthesized by a simple method. The compound is characterized using infra-red (IR) and 1 H-NMR spectral techniques. The chemosensor showed Cd2+ ion selectivity and sensitivity in aqueous solution. The stoichiometry and the binding constants were determined using fluorescence spectroscopy. Piperidine-4-one shows a 1:1 stoichiometric binding to Cd2+ . The limit of detection of Cd2+ was reported.

Loading of atorvastatin and linezolid in ß-cyclodextrin-conjugated cadmium selenide/silica nanoparticles: A spectroscopic study.

The preparation of ß-cyclodextrin-conjugated cadmium selenide-silica nanoparticles, the loading of two drugs viz., Atorvastatin and linezolid in the cyclodextrin cavity, and the fluorescence energy transfer between CdSe/SiO2 nanoparticles and the drugs encapsulated in the cyclodextrin cavity are reported in this paper. IR spectroscopy, X-ray diffractometry, transmission electron microscopy, and particle size analysis by light-scattering experiment were used as the tools of characterizing the size and the crystal system of the nanoparticles. The nanoparticles fall under hexagonal system. The silica-shell containing CdSe nanoparticles were functionalized by reaction with aminoethylamino-ß-cyclodextrin. Fluorescence spectra of the nanoparticles in their free and drug-encapsulated forms were studied. The FÖrster distances between the encapsulated drugs and the CdSe nanoparticles are below 3nm. The change in the FÖrster resonance energy parameters under physiological conditions may aid in tracking the release of drugs from the cavity of the cyclodextrin.