K. Sanjana P. Devi

Thermal and pH responsive polymer-tethered multifunctional magnetic nanoparticles for targeted delivery of anticancer drug.

Targeted and efficient delivery of therapeutics to tumor cells is one of the key issues in cancer therapy. In the present work, we report a temperature and pH dual responsive core-shell nanoparticles comprising smart polymer shell coated on magnetic nanoparticles as an anticancer drug carrier and cancer cell-specific targeting agent. Magnetite nanoparticles (MNPs), prepared by a simple coprecipitation method, was surface modified by introducing amine groups using 3-aminopropyltriethoxysilane. Dual-responsive poly(N-isopropylacrylamide)-block-poly(acrylic acid) copolymer, synthesized by reversible addition-fragmentation chain transfer (RAFT) polymerization, was then attached to the amine-functionalized MNPs via EDC/NHS method. Further, to accomplish cancer-specific targeting properties, folic acid was tethered to the surface of the nanoparticles. Thereafter, rhodamine B isothiocyanate was conjugated to endow fluorescent property to the MNPs required for cellular imaging applications. The nanoparticles were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), selected area electron diffraction (SAED), field emission scanning electron microscopy (FESEM), energy-dispersive X-ray spectroscopy (EDX), thermogravimetric analysis (TGA), zeta potential, vibrating sample magnetometer (VSM), X-ray photoelectron spectroscopy (XPS) measurements, and FTIR, UV-vis spectral analysis. Doxorubicin (DOX), an anticancer drug used for the present study, was loaded into the nanoparticles and its release behavior was subsequently studied. Result showed a sustained release of DOX preferentially at the desired lysosomal pH and temperature condition. The biological activity of the DOX-loaded MNPs was studied by MTT assay, fluorescence microscopy, and apoptosis. Intracellular-uptake studies revealed preferential uptake of these nanoparticles into cancer cells (HeLa cells) compared to normal fibroblast cells (L929 cells). The in vitro apoptosis study revealed that the DOX-loaded nanoparticles caused significant death to the HeLa cells. These nanoparticles were capable of target specific release of the loaded drug in response to pH and temperature and hence may serve as a potential drug carrier for in vivo applications.

Biocompatible mesoporous silica-coated superparamagnetic manganese ferrite nanoparticles for targeted drug delivery and MR imaging applications

Multifunctional mesoporous silica-coated superparamagnetic manganese ferrite (MnFe2O4) nanoparticles (M-MSN) were synthesized and evaluated for targeted drug delivery and magnetic resonance imaging (MRI) applications. MnFe2O4 nanoparticles were prepared by solvothermal route and were silica-coated by surface silylation using sol-gel reactions. Subsequently, silylation was done using (3-aminopropyl)triethoxysilane in presence of a surfactant (CTAB), followed by selective etching of the surfactant molecules that resulted in amine-functionalized superparamagnetic nanoparticles (NH2-MSN). Further modification of the surface of the NH2-MSN with targeting (folate) or fluorescent (RITC) molecules resulted in M-MSN. The formation of the M-MSN was proved by several characterization techniques viz. XRD, XPS, HRTEM, FESEM, VSM, BET surface area measurement, FTIR, and UV-Vis spectroscopy. The M-MSN were loaded with anticancer drug Doxorubicin and the efficacy of the DOX loaded M-MSN was evaluated through in vitro cytotoxicity, fluorescence microscopy, and apoptosis studies. The in vivo biocompatibility of the M-MSN was demonstrated in a mice-model system. Moreover, the M-MSN also acted as superior MRI contrast agent owing to a high magnetization value as well as superparamagnetic behavior at room temperature. These folate-conjugated nanoparticles (FA-MSN) exhibited stronger T2-weighted MRI contrast towards HeLa cells as compared to the nanoparticles without folate conjugation, justifying their potential importance in MRI based diagnosis of cancer. Such M-MSN with a magnetic core required for MRI imaging, a porous shell for carrying drug molecules, a targeting moeity for cancer cell specificity and a fluorescent molecule for imaging, all integrated into a single system, may potentially serve as an excellent material in biomedical applications.

Antioxidant and immunostimulant β-glucan from edible mushroom Russula albonigra (Krombh.) Fr.

A water soluble β-glucan (PS) with an average molecular weight ∼1.95 × 10(5)Da was isolated from the alkaline extract of ectomycorrhizal edible mushroom, Russula albonigra (Krombh.) Fr. and found to consist of terminal, (1 → 3)-, (1 → 6)-, and (1 → 3,6)-linked β-D-glucopyranosyl moieties in a ratio of nearly 1:2:2:1. The structure of this PS was elucidated on the basis of total hydrolysis, methylation analysis, Smith degradation, partial hydrolysis, and 1D/2D NMR experiments. On the basis of these experiments, the repeating unit of the PS was found to contain a backbone of three (1 → 6)-β-D-glucopyranosyl residues, one of which was branched at O-3 position with the side chain consisting of two (1 → 3)-β-D-glucopyranosyl and a terminal β-D-glucopyranosyl residue. This PS showed in vitro macrophage activation by NO production as well as splenocytes and thymocytes proliferation. Moreover, it also exhibited potent antioxidant activities.

A heteroglycan from the mycelia of Pleurotus ostreatus: structure determination and study of antioxidant properties

A heteroglycan (PS) isolated from the mycelia of Pleurotus ostreatus was found to consist of l-fucose, d-mannose, and d-glucose in a molar ratio of nearly 1:2:3. On the basis of acid hydrolysis, methylation analysis, periodate oxidation, and NMR studies (1H, 13C, TOCSY, DQF-COSY, NOESY, ROESY, HSQC, HMBC, and DEPT), the structure of the repeating unit of the PS was determined. The repeating unit had a branched backbone composed of (1→6)-linked α and βd-glucose and (1→2)-linked α-l-fucose. Branching occurred at C-4 position of (1→6)-linked α-d-glucopyranosyl residue with terminal β-d-mannose and C-3 position of (1→6)-linked β-d-glucopyranosyl residue with (1→6)-α-d-mannopyranosyl moiety terminated by α-d-glucose. The structure of the repeating unit of the PS was proposed as: [formula: see text]. The antioxidant properties of the PS were studied. The scavenging activity of hydroxyl free radicals whose EC50 value of PS at 943 μg/mL was determined. Further, EC50 value of the PS at 53 μg/mL was observed for scavenging activity of superoxide free radicals. Chelating effects (54.82%) of ferrous ions were observed at 1mg/mL of the PS.

Facile preparation of multifunctional hollow silica nanoparticles and their cancer specific targeting effect

Efficient delivery of therapeutics to tumor cells is one of the key issues in cancer therapy. In the present work, we have established a facile and unique chemical strategy for fabrication of highly biocompatible and water-dispersible multifunctional hollow silica nanoparticles (HSNPs). These mesoporous silica nanoparticles, having ring-like morphology, were fabricated by the sol-gel method followed by selective etching of the inner inorganic core. Further, to accomplish cancer-specific targeting properties, folic acid was tethered to the surface of HSNPs through amide bond formation using the EDC/NHS coupling method. Thereafter, rhodamine B isothiocyanate (RITC) was conjugated to the HSNPs to endow the fluorescent property to the nanoparticles required for biological imaging applications. The successful formation of multifunctional HSNPs was confirmed by XRD, FTIR, zeta potential, TEM, FESEM, and BET surface area measurements. The average particle size of HSNPs was found to be 50 nm to 70 nm from TEM analysis, which is the desired size-range for drug-delivery vehicles. These HSNPs showed good mesoporous behavior and were found to be an excellent candidate for loading and releasing the anticancer drug doxorubicin (DOX). The bioactivity of the HSNPs was verified by biological assay including cell cytotoxicity by MTT assay, intracellular uptake by fluorescence microscopy, cell cycle analysis by fluorescence-activated cell sorting (FACS), and apoptosis study. Besides, the effect of salt concentration on the drug release performance was evaluated. An in vitro biological study revealed that these DOX-loaded folate-targeted HSNPs achieved excellent efficacy for simultaneously targeting and destroying cancer cells.

Characterization and lectin microarray of an immunomodulatory heteroglucan from Pleurotus ostreatus mycelia

Glucans isolated from various mushroom and mycelia sources are interestingly being studied nowadays as a potent therapeutic agent. The present work was focused on the isolation, characterization and immunomodulatory study of a novel water soluble glucan from the pure mycelia of Pleurotus ostreatus. The extracted glucan was found to have a high molecular weight of ∼2.7 × 10(6)Da and mainly comprised of glucose, mannose and fucose in a ratio of 3:2:1 with both β and α linkages. Presence of terminal or interior glucose, mannose and fucose residues was also revealed using a high throughput miniaturized platform of lectin microarray. The heteroglucan folded into a triple helical conformation and exhibited enhanced immune cell activation and anti-tumor potential in tumor bearing mice model. Thus, potential biological functions incorporated in these glucan molecules acts in accord with its structural property and exploration of such structure-function relationship will unveil its diverse mechanism of action.

Glucan from hot aqueous extract of an ectomycorrhizal edible mushroom, Russula albonigra (Krombh.) Fr.: structural characterization and study of immunoenhancing properties

A water soluble glucan (PS-I) was isolated from the hot aqueous extract of the fruit bodies of an ectomycorrhizal edible mushroom, Russula albonigra (Krombh.) Fr. The total hydrolysis, methylation analysis, periodate oxidation, and NMR ((1)H, (13)C, DEPT-135, TOCSY, DQF-COSY, NOESY, ROESY, HSQC, and HMBC) studies revealed the presence of the following repeating unit in the polysaccharide: This glucan showed excellent activation of macrophages as well as splenocytes and thymocytes in vitro.

Structural and immunological studies of hetero polysaccharide isolated from the alkaline extract of Tricholoma crassum (Berk.) Sacc.

An immunoenhancing water-soluble hetero polysaccharide was isolated from an alkaline extract of the fruit bodies of an ectomycorrhizal edible mushroom, Tricholoma crassum (Berk.) Sacc. The structure of the molecule was investigated using acid hydrolysis, methylation analysis; periodate oxidation study, and NMR spectroscopy techniques ((1)H, (13)C, DEPT-135, DQF-COSY, TOCSY, NOESY, ROESY, HSQC, and HMBC). On the basis of the above-mentioned experiments the structure of the repeating unit of the polysaccharide was established as: This polysaccharide exhibited splenocyte, thymocyte as well as macrophage activations.

Pectic polysaccharide from the green fruits of Momordica charantia (Karela): structural characterization and study of immunoenhancing and antioxidant properties

A water soluble pectic polysaccharide (PS) isolated from the aqueous extract of the green fruits of Momordica charantia contains D-galactose and D-methyl galacturonate in a molar ratio of nearly 1:4. It showed splenocyte, thymocyte as well as macrophage activations. Moreover, it exhibited potent antioxidant activities. On the basis of total acid hydrolysis, methylation analysis, periodate oxidation, and 1D and 2D NMR studies, the structure of the repeating unit of the pectic polysaccharide was established as: [Formula: see text].

A glucan from an ectomycorrhizal edible mushroom Tricholoma crassum (Berk.) Sacc.: isolation, characterization, and biological studies

A water soluble glucan of average molecular weight ∼1.74×10(5)Da was isolated from hot aqueous extract of the fruiting bodies of an ectomycorrhizal edible mushroom Tricholoma crassum (Berk.) Sacc. The structure of this glucan was elucidated on the basis of total hydrolysis, methylation analysis, Smith degradation, and 1D/2D NMR studies. Based on the above experiments the repeating unit of the glucan was established as: [formula see text]. This glucan showed macrophage activation in vitro by NO production in a dose dependent manner and strong splenocyte and thymocyte immunostimulation in mouse cell culture medium. It also exhibited good inhibition activity toward lipid peroxidation.