Showing papers by "Nikhil R. Jana published in 2015"

Clathrin to Lipid Raft-Endocytosis via Controlled Surface Chemistry and Efficient Perinuclear Targeting of Nanoparticle

Abstract: Nanoparticle interacts with live cells depending on their surface chemistry, enters into cell via endocytosis, and is commonly trafficked to an endosome/lysozome that restricts subcellular targeting options. Here we show that nanoparticle surface chemistry can be tuned to alter their cell uptake mechanism and subcellular trafficking. Quantum dot based nanoprobes of 20–30 nm hydrodynamic diameters have been synthesized with tunable surface charge (between +15 mV to −25 mV) and lipophilicity to influence their cellular uptake processes and subcellular trafficking. It is observed that cationic nanoprobe electrostatically interacts with cell membrane and enters into cell via clathrin-mediated endocytosis. At lower surface charge (between +10 mV to −10 mV), the electrostatic interaction with cell membrane becomes weaker, and additional lipid raft endocytosis is initiated. If a lipophilic functional group is introduced on a weakly anionic nanoparticle surface, the uptake mechanism shifts to predominant lipid ra...

Design and Synthesis of Triphenylphosphonium Functionalized Nanoparticle Probe for Mitochondria Targeting and Imaging

Abstract: Although various nanoparticle based cellular imaging probes are reported as alternatives for conventional molecular probes, the development of nanoparticle based subcellular imaging probes is challenging. Here we report inorganic nanoparticle based fluorescent probes of 30–40 nm hydrodynamic diameter that can target and label mitochondia. Nanoprobe has pH responsive polyacrylate shell with both anionic and cationic surface charge and functionalized with triphenylphosphonium group. Optimized surface chemistry offers high cellular uptake via predominate caveolae mediated endocytosis, and triphenylphosphonium group traffics them to mitochondria. This concept of surface chemistry can be extended to different nanoparticles and for development of other subcellular imaging nanoprobes.

Detection and Monitoring of Amyloid Fibrillation Using a Fluorescence “Switch-On” Probe

Abstract: Amyloid protein fibrillation is associated with a variety of neurodegenerative and other diseases, and their efficient detection and monitoring can greatly advance early diagnosis and therapy. Herein, we report a fluorescent “switch-on” probe for the reliable detection and monitoring of amyloid fibrils. The probe consists of a peptide component for binding with amyloid structure and a color component with an aggregation-induced green emission property. This probe is nonfluorescent in the presence of amyloid forming monomer protein/peptide, but fluorescence “switch-on” occurs after binding with amyloid fibrils. Compared to conventionally used thioflavin T, this probe offers a high signal-to-noise ratio, which is unaffected by the quencher ion/nanoparticle. The proposed new probe has been used for the detection and monitoring of amyloid fibrils produced by a wide variety of amyloid protein/peptides and can be extended for in vitro diagnostic applications.

β-Cyclodextrin functionalized magnetic mesoporous silica colloid for cholesterol separation.

Abstract: Although cholesterol plays significant biochemical function in the human body, excess of it leads to various disorders, and thus, its control/separation is important in medical science and food industries. However, efficient and selective separation of cholesterol is challenging because cholesterol often exists in microheterogeneous or insoluble forms in remote organ and exists with other chemicals/biochemicals. Here, we have described a colloidal magnetic mesoporous silica (MMS)-based approach for efficient separation of cholesterol in different forms. MMS is functionalized with β-cyclodextrin for selective binding with cholesterol via host–guest interaction. The colloidal form of MMS offers effective interaction with cholesterol of any form, and magnetic property of MMS offers easier separation of bound cholesterol. Functionalized MMS is efficient in separating cholesterol crystals, water-insoluble cholesterol, and the microheterogeneous form of cholesterol from milk or a cellular environment. Developed...

Paper-based microfluidic approach for surface-enhanced raman spectroscopy and highly reproducible detection of proteins beyond picomolar concentration.

Abstract: Although microfluidic approach is widely used in various point of care diagnostics, its implementation in surface enhanced Raman spectroscopy (SERS)-based detection is challenging. This is because SERS signal depends on plasmonic nanoparticle aggregation induced generation of stable electromagnetic hot spots and in currently available microfluidic platform this condition is difficult to adapt. Here we show that SERS can be adapted using simple paper based microfluidic system where both the plasmonic nanomaterials and analyte are used in mobile phase. This approach allows analyte induced controlled particle aggregation and electromagnetic hot spot generation inside the microfluidic channel with the resultant SERS signal, which is highly reproducible and sensitive. This approach has been used for reproducible detection of protein in the pico to femtomolar concentration. Presented approach is simple, rapid, and cost-effective, and requires low sample volume. Method can be extended for SERS-based detection of...

Separation of Microcystin-LR by Cyclodextrin-Functionalized Magnetic Composite of Colloidal Graphene and Porous Silica

Abstract: Microcystin-LR belongs to the family of microcystins produced by cyanobacteria and known to be the most toxic of this family. Existence of cyanobacteria in water bodies leads to the contamination of drinking water with microcystin-LR and thus their separation is essential for an advanced water purification system. Here we report functional nanocomposite-based selective separation of microcystin-LR from contaminated water. We have synthesized cyclodextrin-functionalized magnetic composite of colloidal graphene and porous silica where the cyclodextrin component offers host-guest interaction with microcystin-LR and the magnetic component offers easier separation of microcystin-LR from water. High surface area and large extent of chemical functional groups offer high loading (up to 18 wt %) of cyclodextrin with these nanocomposites, and the dispersible form of the nanocomposite offers easier accessibility of cyclodextrin to microcystin-LR. We have shown that microcystin-LR separation efficiency is significantly enhanced after functionalization with cyclodextrin, and among all the tested cyclodextrins, γ-cyclodextrin offers the best performance. We have also found that graphene-based nanocomposite offers better performance over porous silica-based nanocomposite due to better accessibility of cyclodextrins for interaction with microcystin-LR. The proposed graphene-based functional nanocomposite is environment friendly, reusable, and applicable for advanced water purification.

Dopamine functionalized polymeric nanoparticle for targeted drug delivery

Abstract: A biocompatible drug delivery nanocarrier with cellular and subcellular targeting properties can greatly enhance the therapeutic effect towards various diseases. Here, we report polyaspartamide based functional polymeric nanoparticles as drug delivery carriers for targeting at the cellular and subcellular length scale. The polymeric nanoparticle has a polyaspartamide backbone with both octadecyl and dopamine functional groups and produces polymeric nanoparticles in water with the exposed dopamine. This polymeric nanoparticle has good encapsulation efficiency for hydrophobic drugs and offers cellular delivery of the drug into dopamine receptor positive human colon adenocarcinoma cells. Using this approach three different drugs (e.g. curcumin, camptothecin and doxorubicin) are selectively delivered to human colon adenocarcinoma cells. Subcellular imaging study shows that the delivered drugs retain their ability to target subcellular organelles and thus curcumin targets mitochondria and doxorubicin targets the nucleus. This polymeric nanoparticle can be used as an alternative drug delivery carrier for in vitro and in vivo applications.

Interplay of electrostatics and lipid packing determines the binding of charged polymer coated nanoparticles to model membranes

Abstract: Understanding of nanoparticle-membrane interactions is useful for various applications of nanoparticles like drug delivery and imaging. Here we report on the studies of interaction between hydrophilic charged polymer coated semiconductor quantum dot nanoparticles with model lipid membranes. Atomic force microscopy and X-ray reflectivity measurements suggest that cationic nanoparticles bind and penetrate bilayers of zwitterionic lipids. Penetration and binding depend on the extent of lipid packing and result in the disruption of the lipid bilayer accompanied by enhanced lipid diffusion. On the other hand, anionic nanoparticles show minimal membrane binding although, curiously, their interaction leads to reduction in lipid diffusivity. It is suggested that the enhanced binding of cationic QDs at higher lipid packing can be understood in terms of the effective surface potential of the bilayers which is tunable through membrane lipid packing. Our results bring forth the subtle interplay of membrane lipid packing and electrostatics which determine nanoparticle binding and penetration of model membranes with further implications for real cell membranes.

Effect of size and oxidation state of platinum nanoparticles on the electrocatalytic performance of graphene-nanoparticle composites

Abstract: A surfactant and stabilizer free graphene-based composite with Pt nanoparticles is considered to be a promising electrocatalyst with greatly improved performance. Here we show that both the size and oxidation state of Pt nanoparticles can significantly influence the electrocatalytic performance of the nanocomposite. We have synthesized Pt–graphene nanocomposites with varied sizes and oxidation states of Pt nanoparticles and test their catalytic activity towards methanol electro-oxidation. We found that the size <1.5 nm with mixed oxidation offers methanol oxidation at lower onset potential and with better tolerance to CO poisoning. However, these benefits are lost due to catalyst durability and thus catalytic current decays rapidly with time. As the nanoparticle size increases in the range of 2–5 nm this onset potential increases, CO tolerance decreases but the catalytic current becomes more stable with time. Thus an optimum nanoparticle size of 2.2 nm shows the best catalytic activity and durability. The oxygenic platinum with variable oxidation states offers stable grafting with the graphene surface, prevents active Pt (0) sites and assists for better CO tolerance. This result would be useful in the design and development of electrocatalysts with better performances.

Therapeutic use of fisetin, curcumin, and mesoporous carbon nanoparticle loaded fisetin in bleomycin-induced idiopathic pulmonary fibrosis

Abstract: Idiopathic pulmonary fibrosis (IPF) is a devastating disease of unknown etiology, for which there is no curative pharmacological therapy. Bleomycin, an anti-neoplastic agent that causes lung fibrosis in human patients has been used extensively in rodent models to mimic IPF. The conventional therapy has been steroids and immunosuppressive agents. But only a minority of patients responds to such a therapy. IPF is a progressive, ultimately fatal disorder for which substantive medical therapy is desperately needed. Fisetin is a flavonol which inhibits the activity of several pro-inflammatory cytokines. The polyphenol curcumin is used to treat inflammatory diseases, abdominal disorders, and a variety of other ailments. The aim of this study was to evaluate the beneficial effect of fistine, curcumin and mesoporous carbaon nanoparticle (MCN) loaded fisetin as an anti-inflammatory agents against bleomycin-induced changes in mice with IPF. In our study, flavonoids showed their anti fibrotic action. The inflammatory cell count was greatly increased for bleo treated individuals and effectiveness of fisein was increased after addition of MCN particles with it, curcumin also showed anti- inflammatory effects. In another experiment, bleomycin effectively inhibits the cellular recruitment to the spleen and treatment with fisetin, and curcumin increases the cellular recruitment in spleen. Colony count was also increased in MCN+fisetin treated groups, and it was statistically significant. We also observed the increased level of cytokines with fisetin treatment, with curcumin treatment and with MCN +fisetin treatment as compared to the bleo treated sample. In conclusion, the present research suggests that fisetin and curcumin and MCN loaded fisetin may be a promising therapeutic agent for bleomycin-induced changes in mice with IPF. This will open up new perspectives for a potential role of these drugs as a molecular target in Idiopathic pulmonary fibrosis.

Mesoporous Nano-carbon Particle Loaded Fisetin has a Positive Therapeutic Effect in a Murine Preclinical Model of Ovalbumin Induced Acute Allergic Asthma

Abstract: Inflammation is a complex process initiated by several factors ranging from bacterial infection and chemical injury to environmental pollution that causes cell injury or death, release of inflammatory mediators which further trigger the up-regulation of other pro-inflammatory cytokines and chemokines as well as sequestration of specific immunoglobulin molecules. Th2 inflammation is an allergenic reaction by primed T and B cells and during manifestation of acute asthma, this immune reaction takes the form of super-activated macrophages, eosinophils, neutrophils and an array of Th2 skewed inflammasome development. An anti-inflammatory molecule should be able to potently reduce or inhibit one or more of the aforementioned traits. Several organic and inorganic substances have been studied to evaluate their potential as anti-inflammatory molecules, among which nanotechnology has emerged as a promising aid to anti-inflammatory activities. Nanoparticle-incorporated mesoporous carbon particles have a wide range of applications in controlled drug delivery. These nano particles are capable of delivering drugs inside the cell, even in a sub-cellular organelle specific manner. In this study, inflammation is initiated by using different classes of pro-inflammatory stimuli, such as OVA (chicken ovalbumin), LPS (lipopolysaccharide) and TG (thioglycollate), and by applying such nano-concoctions, the anti-inflammatory activities of certain compounds are assessed in in vivo models. The anti- inflammatory action of a novel drug made from extract of strawberry (fisetin) has been evaluated in an in vivo model of acute allergic asthma in Balb/c mice. Also, attempts are being made to narrow the delivery window within the cell, by loading the drug onto the constructed mesoporous carbon nanoparticle. It has been found to maintain cell viability significantly by reducing oxidative and nitrosative stress and ameliorating the overall development of composite asthma phenotype in this murine preclinical model.

Graphene-Based Carbon Nanoparticles for Bioimaging Applications

Abstract: Fluorescent nanoparticle-based imaging probes are expected to generate new medical diagnostic tools because of their superior brightness and photostability. Although significant progress has been made regarding fluorescent semiconductor nanocrystal-based biological labeling, presence of heavy metals and their associated toxicity issues have severely limited their application potential. Fluorescent carbon nanoparticle appears as an alternative nontoxic imaging probe suitable for biological staining and diagnostics. The chemical synthesis of highly fluorescent carbon nanoparticles in the range of 1–10 nm and with size-dependent tunable visible emission is significantly advanced. These carbon nanoparticles could be transformed into various functional nanoprobes of 5–15 nm hydrodynamic diameters and could be used as a cell imaging probe. Stable and tunable visible emission, similar to semi-conductor nanocrystals, but small hydrodynamic size and low toxicity would offer wider application of these nanoprobes in biomedical science.

Therapeutic use of Fisetin and Fisetin Loaded on Mesoporous Carbon Nanoparticle (MCN) in Thioglycollate-induced Peritonitis

Abstract: Background: The pathophysiology of aseptic peritonitis involves inflammation of the serosal membrane that lines the abdominal cavity and the organs contained therein. The etiology of peritonitis is complicated and is involved in various processes, of which, the most important one is the inflammatory reaction. During the pathological process of peritonitis, NF-κB plays an activating role in the inflammatory reaction, which might be a potential therapeutic target in the therapy of certain inflammatory diseases. We studied the anti-inflammatory and pro-regenerative actions of Fisetin, a flavonol found in many plants, in a mouse model of thioglycollate-induced peritonitis, as well as the actions of fisetin administered with a nanoparticle such as mesoporous carbon nanoparticle (MCN). BALB/c mice were used in this study. Results: We found cell recruitment in the blood increased with the administration of thioglycollate (TG) after 24 h, 48 h, 72 h and 96 h, showing that it has induced inflammation. Cell recruitment was successfully inhibited by fisetin, and with MCN+fisetin. In the peritoneal fluid, total cell recruitment was increased, which was successfully inhibited with fisetin and MCN+fisetin treatment. TG treatment significantly reduced cell proliferation in the blood, PF and BM, within 24 h, till 96 h. Interestingly, cell proliferation increased with fisetin treatment, and with MCN+fisetin. The clonogenic potential of the tissues decreased significantly within 24 h, with administration of TG. Both fisetin treatment and MCN+fisetin treatment restored the clonogenic potential of the tissues. There was a decrease in Th2 cytokines with TG treatment, in blood after 48 h, and both fisetin and MCN+fisetin increased the cytokine content. Conclusion: In conclusion, we found that fisetin had a promising therapeutic effect on the peritonitis.