Biomedical subjects

Russell J Mumper

Publications and source records attributed to Russell J Mumper.

32 records · Page 2Linked to original sources

PubMed2003

Physical characterization and macrophage cell uptake of mannan-coated nanoparticles.

Previously, we reported on a cationic nanoparticle-based DNA vaccine delivery system engineered from warm oil-in-water microemulsion precursors. In these present studies, the feasibility of lyophilizing the nanoparticles and their thermal properties were investigated. Also, the binding and uptake of the nanoparticles by a macrophage cell line were studied. The nanoparticles (prior to pDNA coating) were freeze-dried with lactose or sucrose as cryoprotectants. The stability of lyophilized nanoparticles at room temperature was monitored and compared to that of the aqueous nanoparticle suspension. The thermal properties of the nanoparticles were investigated using differential scanning calorimetry (DSC). The nanoparticles, coated or uncoated with mannan as a ligand, were incubated with a mannose receptor positive (MR+) mouse macrophage cell line (J774E), at either 4 degrees C or 37 degrees C to study the binding and uptake of the nanoparticles by the cells. It was found that lactose or sucrose (1-5%, w/v) was required for successful lyophilization of the nanoparticles. After 4 months of storage, the size of lyophilized nanoparticles did not significantly increase while those in aqueous suspension grew by over 900%. Unlike its individual components, emulsifying wax (m.p., approximately 55 degrees C) and hexadecyltrimethyl ammonium bromide, the nanoparticles showed a melting point of approximately 90 degrees C. Moreover, the DSC profile of the nanoparticles was different from that of the physical mixture of emulsifying wax and CTAB. After 1 hour incubation at 37 degrees C, the uptake of mannan-coated nanoparticles was 50% higher than that of the uncoated nanoparticles. At 4 degrees C and after one hour, the binding of the mannan-coated nanoparticles by J774E was over 2-fold higher than that of the uncoated nanoparticles. This increase in J774E binding could be abolished by preincubating the cells with free mannan, suggesting that the binding and uptake were receptor-mediated. In conclusion, the nanoparticles were lyophilizable, and lyophilization was shown to enhance the stability of the nanoparticles. DSC provided evidence that the nanoparticles were not a physical mixture of their individual components. Finally, cell binding and uptake studies demonstrated that the nanoparticles have potential application for cell-specific targeting.

Animals↗

PubMed2003

Preparation and characterization of novel coenzyme Q10 nanoparticles engineered from microemulsion precursors.

The purpose of these studies was to prepare and characterize nanoparticles into which Coenzyme Q10 (CoQ10) had been incorporated (CoQ10-NPs) using a simple and potentially scalable method. CoQ10-NPs were prepared by cooling warm microemulsion precursors composed of emulsifying wax, CoQ10, Brij 78, and/or Tween 20. The nanoparticles were lyophilized, and the stability of CoQ10-NPs in both lyophilized form and aqueous suspension was monitored over 7 days. The release of CoQ10 from the nanoparticles was investigated at 37 degrees C. Finally, an in vitro study of the uptake of CoQ10-NPs by mouse macrophage, J774A.1, was completed. The incorporation efficiency of CoQ10 was approximately 74% +/- 5%. Differential Scanning Calorimetry (DSC) showed that the nanoparticle was not a physical mixture of its individual components. The size of the nanoparticles increased over time if stored in aqueous suspension. However, enhanced stability was observed when the nanoparticles were stored at 4 degrees C. Storage in lyophilized form demonstrated the highest stability. The in vitro release profile of CoQ10 from the nanoparticles showed an initial period of rapid release in the first 9 hours followed by a period of slower and extended release. The uptake of CoQ10-NPs by the J774A.1 cells was over 4-fold higher than that of the CoQ10-free nanoparticles (P < .05). In conclusion, CoQ10-NPs with potential application for oral CoQ10 delivery were engineered readily from microemulsion precursors.

Animals↗

PubMed2003

Microparticles and nanoparticles as delivery systems for DNA vaccines.

DNA vaccines, also referred to as genetic vaccines, are generating significant preclinical and clinical interest. It has been proven that the expression of an antigen or antigens from plasmid DNA (pDNA) may elicit both humoral and cellular immune responses. Therefore, DNA vaccines may have potential as new vaccines for important pathogens such as HIV, hepatitis C, tuberculosis, and malaria. However, the clinical results using "naked" pDNA have been disappointing in the breadth and depth of the immune response and the relatively high doses of pDNA needed to elicit a response. Clinical trials with the gene gun have been promising, but it is unclear whether this technology will be commercially viable. As a result, there exists a clear need for new vaccine delivery systems that can be administered at low doses to elicit strong humoral and cellular immune responses. One promising approach is the development of microparticles and nanoparticles as delivery systems for DNA vaccines. In this review, the application of microparticles and nanoparticles as DNA vaccine delivery systems will be critically reviewed with a primary focus on those systems that have generated in vivo immune responses.

Adjuvants, Immunologic↗

PubMed2002

Topical immunization using nanoengineered genetic vaccines.

DNA vaccines have been shown to elicit both broad humoral and cellular immune responses. Needle-free injection devices and the gene gun have been used to deliver these DNA vaccines to dendritic cells in the viable skin epidermis with some success. However, more cost-effective and dendritic cell (DC)-targeted immunization strategies are sought. To this end, a nanoengineered genetic vaccine for simple topical application was developed. Expressed beta-galactosidase was used as a model antigen. Plasmid DNA was coated on the surface of preformed cationic nanoparticles engineered directly from warm oil-in-water (O/W) microemulsion precursors comprised of emulsifying wax as the oil phase and CTAB as a cationic surfactant. Mannan, a DC ligand, was coated on the nanoparticles with and without entrapped endosomolytic agents, dioleoyl phosphatidylethanolamine (DOPE) and cholesterol. In-vitro cell transfection studies were performed to confirm transgene expression with these pDNA-coated nanoparticles. An in-vitro Concanavalin A (ConA) agglutination assay confirmed the presence of mannan on the surface of nanoparticles. The humoral and proliferative immune responses were assessed after topical application of these nanoengineered systems to the skin of shaved Balb/C mice. All pDNA-coated nanoparticles, especially the mannan-coated pDNA-nanoparticles with DOPE, resulted in significant enhancement in both antigen-specific IgG titers (16-fold) and splenocyte proliferation over 'naked' pDNA alone.

Administration, Topical↗

PubMed2002

Coating of cationized protein on engineered nanoparticles results in enhanced immune responses.

A significant emphasis has been placed on the development of improved adjuvants and delivery systems to improve both antibody production and cell-mediated immunity. The overall goal of this project was to cationize a model protein antigen, beta-galactosidase (nGal), coat the cationized Gal (cGal) on the surface of novel anionic nanoparticles engineered from microemulsion precursors, and assess the immune response of this system after subcutaneous injection to mice. Gal was chemically cationized as evidenced by gel electrophoresis. The cGal was coated on anionic nanoparticles (78+/-11 nm) engineered from oil-in-water microemulsion precursors to produce cGal-coated nanoparticles. The immune response to nGal with 'Alum', cGal alone, and cGal-coated nanoparticles were assessed after subcutaneous injection to Balb/c mice. cGal alone elicited similar antibody titer to nGal with 'Alum'. However, cGal-coated nanoparticles elicited the strongest and most reproducible antibody titer. cGal alone produced very high levels of Th1 cytokines, but low levels of Th2 cytokines. In contrast, cGal-coated nanoparticles significantly enhanced both the Th1 and Th2 cytokines. The results demonstrated the utility of antigen-coated nanoparticles to enhance both the humoral and Th1-type immune responses, in parallel.

Adjuvants, Immunologic↗

PubMed2002

Transmucosal delivery of testosterone in rabbits using novel bi-layer mucoadhesive wax-film composite disks.

Testosterone exhibits very low oral bioavailability because of its low aqueous solubility and extensive first-pass metabolism. The purpose of this study was to develop a novel bi-layer mucoadhesive wax-film composite (WFC), and to test the relative bioavailability of testosterone via the buccal route in rabbits. The release rate of testosterone from optimal WFCs (3/8-in. diameter) per unit surface area was 5.6 microg x cm(2) x mL(-1) x min(-1) and was zero-order. Bi-layer WFCs (average weight of 14 +/- 2.6 mg and thickness of 186 +/- 34 microns) containing 4 mg of testosterone were applied to the buccal pouch of anesthetized New Zealand white rabbits. Rabbits (n = 3) injected intravenously had C(max) and area under the curve values of 1200 +/- 46 ng/mL, and 48,227 +/- 12,995 ng x min/mL, respectively. Rabbits (n = 3) dosed via the buccal pouch had C(max), T(max), and area under the curve values of 127 +/- 13 ng/mL, 200 +/- 35 min, and 24,221 +/- 1543 ng x min/mL. The relative bioavailability for rabbits treated with the WFC was 50.2 +/- 3.2% with a coefficient of variation of 6.4%. It was concluded that these bi-layer mucoadhesive WFCs disks could deliver physiologically relevant amounts of insoluble drugs such as testosterone across the buccal mucosa.

Acrylic Resins↗

PubMed2002

Genetic immunization using nanoparticles engineered from microemulsion precursors.

PURPOSE: Genetic immunization using "naked" plasmid DNA (pDNA) has been shown to elicit broad humoral and cellular immune responses. However, more versatile and perhaps cell-targeted delivery systems are needed. To this end, a novel process to engineer cationic nanoparticles coated with pDNA for genetic immunization was explored. METHODS; Cationic nanoparticles were engineered from warm oil-in-water microemulsion precursors composed of emulsifying wax as the oil phase and cetyltrimethylammonium bromide (CTAB) as the cationic surfactant. Plasmid DNA was coated on the surface of the cationic nanoparticles to produce pDNA-coated nanoparticles. An endosomolytic lipid and/or a dendritic cell-targeting ligand (mannan) were incorporated in or deposited on the nanoparticles to enhance the in vitro cell transfection efficiency and the in vivo immune responses after subcutaneous injection to Balb/C mice. The IgG titer to expressed beta-galactosidase and the cytokine release from isolated splenocytes after stimulation were determined on 28 days. RESULTS: Cationic nanoparticles (around 100 nm) were engineered within minutes. The pDNA-coated nanoparticles were stable at 37 degrees C over 30 min in selected biologic fluids. Transmission electron microscopy showed the nanoparticles were spherical. Plasmid DNA-coated nanoparticles. especially those with both an endosomolytic lipid and dendritic cell-targeting ligand. resulted in significant enhancement in both IgG titer (over 16-fold) and T-helper type-1 (Th1-type) cytokine release (up to 300% increase) over "naked" pDNA. CONCLUSION: A novel method to engineer pDNA-coated nanoparticles for enhanced in vitro cell transfection and enhanced in vivo immune responses was reported.

Animals↗

PubMed2002

Bilayer films for mucosal (genetic) immunization via the buccal route in rabbits.

PURPOSE: The oral buccal mucosa may be an ideal site for mucosal immunization, allowing for the needle-free administration of cost-effective vaccines. A novel mucoadhesive bilayer film was developed to test the feasibility of this route of immunization in rabbits. METHODS: Bilayer films were developed using different ratios of Noveon and Eudragit S-100 as the mucoadhesive layer and a pharmaceutical wax as the impermeable backing layer. Optimal 3/8-inch films were post-loaded with 100 microg of plasmid DNA (CMV-beta-gal) or beta-galactosidase protein. The in vitro release rates and stability of the postloaded antigens were determined. The films were applied to the buccal pouch of rabbits on days 0. 7, and 14, and the humoral and splenocyte proliferative immune responses to beta-gal were determined through day 28 and compared to those responses after conventional subcutaneous injection of adjuvanted protein. RESULTS: The weight ratio of Noveon and Eudragit S-100 had a significant effect on adhesion time of bilayer films. Postloaded plasmid DNA and beta-gal remained stable after being released from bilayer films (release of -60-80% in 2 h for both). Buccal immunization using novel bilayer films (109 +/- 6-microm thickness) containing plasmid DNA led to comparable antigen-specific IgG titer to that of subcutaneous protein injection. All rabbits immunized with plasmid DNA via the buccal route but none by the subcutaneous route with protein antigen demonstrated splenocyte proliferative immune responses. CONCLUSION: The feasibility of buccal (genetic) immunization with these novel bilayer films was demonstrated.

Adhesives↗

PubMed2002

Buccal transmucosal delivery of calcitonin in rabbits using thin-film composites.

PURPOSE: Salmon Calcitonin (sCT) is used to treat hypercalcemia resulting from Paget's disease and osteoporosis. sCT is available either in a sterile injectable form or nasal spray. Alternative and more cost-effective dosage forms for the delivery of calcitonin are needed. We sought to deliver sCT transmucosally using a previously reported mucoadhesive bilayer thin-film composite (TFC) via the buccal route. METHODS: Forty micrograms of salmon calcitonin (200-IU) was loaded on preformed TFCs. In vitro release of sCT from TFCs was monitored in phosphate-buffered saline (10 mM, pH 7.4) at 37degrees C. Female New Zealand White rabbits (n = 6) were dosed with 40 microg of sCT either by injection via the ear vein or by applying sCT-loaded TFCs directly on the buccal pouch. Blood was collected at various times, and the plasma sCT and calcium concentrations were quantified. WinNonlin was used to determine the relevant pharmacokinetic parameters. RESULTS: In vitro, over 80% of sCT was released from the TFCs within 240 min. Super Case-II transport was indicated as the primary release mechanism. Rabbits injected intravenously had C(max), Cls, Vss, and AUC(0-inf) values of 75.1 +/- 6.5 ng/mL, 20.7 +/- 3.3 mL/min, 637 +/- 141 mL, and 1925 +/- 237 ng*min/mL, respectively. Rabbits dosed via the buccal route had C(max) Cls, and AUC(0-400 min values of 4.6 +/- 1.6 ng/mL, 22.0 +/- 5.9 mL/min, and 842.9 +/- 209.7 ng*min/mL, respectively. The relative bioavailability for rabbits treated with the TFCs was 43.8 +/- 10.9% with a CV of 24.9%. The reductions in plasma calcium levels after administration of sCT by both the intravenous and buccal route were comparable. CONCLUSIONS: The TFCs effectively delivered therapeutically efficacious amounts of sCT across the buccal mucosa in rabbits.

Administration, Buccal↗

PubMed2002

Gadolinium-loaded nanoparticles engineered from microemulsion templates.

Microemulsions (oil-in-water) have been used as templates to engineer stable emulsifying wax and Brij 72 (polyoxyl 2 stearyl ether) nanoparticles. The technique is simple, reproducible, and amenable to large-scale production of stable nanoparticles having diameters below 100 nm. Investigation of the process variables showed that the amount of surfactant used in the preparation of microemulsion templates had the greatest influence on the microemulsion window, as well as the properties and stability of the cured nanoparticles. Emulsifying wax and Brij 72 nanoparticles (2 mg/mL) made with 3 mM polyoxyl 20 stearyl ether and 2.3mM polysorbate 80, respectively, were the most stable based on retention of nanoparticle size over time. Gadolinium acetylacetonate (GdAcAc), a potential anticancer agent for neutron capture therapy (NCT), was entrapped in stable nanoparticles. The apparent water solubility of GdAcAc was increased more than 2000-fold by entrapment into nanoparticles. The entrapment efficiency of GdAcAc was about 100% for emulsifying wax nanoparticles and 86% for Brij 72 nanoparticles, as determined by gel permeation chromatography (GPC). Elution profiles were obtained with light scattering (counts per second) to detect nanoparticles and ultraviolet (UV) absorption of GdAcAc at 288 nm. Challenges of these cured nanoparticles in biologically relevant media such as 10% fetal bovine serum, 10 mM phosphate-buffered saline, 150 mM NaCl, and 10% lactose at 37 degrees C for 60 min demonstrated that these nanoparticles are stable. The ease of preparation of these very small and stable nanoparticles, and the ability to entrap lipophilic drugs such as GdAcAc with high efficiency, suggested that these systems may have potential in cell targeting, especially for specific delivery to tumor cells for NCT.

Capsules↗

PubMed2002

Intranasal administration of plasmid DNA-coated nanoparticles results in enhanced immune responses.

Intranasal immunization offers potential forthe elicitation of effective mucosal and systemic immune responses. In this study, a previously reported novel cationic nanoparticle engineered from a microemulsion precursor was further modified, optimized and applied intranasally to mice to explore its potential as a plasmid DNA (pDNA) vaccine delivery system. To this end, more uniform nanoparticles (around 100 nm) containing less cationic surfactant were developed. The pDNA-coated nanoparticles significantly enhanced the specific serum IgG and IgA titres to an expressed model antigen, beta-galactosidase, by 18-28 and 25-30 fold, respectively, when compared with naked pDNA alone. An enhanced splenocyte proliferative response was also observed after immunization with the pDNA-coated nanoparticles. It was concluded that these plasmid DNA-coated nanoparticles may have potential for immunization via the nasal route.

Administration, Intranasal↗

PubMedDate not supplied

Plasmid DNA-entrapped nanoparticles engineered from microemulsion precursors: in vitro and in vivo evaluation.

Nonviral gene therapy has been a rapidly growing field. However, delivery systems that can provide protection for pDNA and potential targeting are still desired. A novel pDNA-nanoparticle delivery system was developed by entrapping hydrophobized pDNA inside nanoparticles engineered from oil-in-water (O/W) microemulsion precursors. Plasmid DNA was hydrophobized by complexing with cationic surfactants DOTAP and DDAB. Warm O/W microemulsions were prepared at 50-55 degrees C with emulsifying wax, Brij 78, Tween 20, and Tween 80. Nanoparticles were engineered by simply cooling the O/W microemulsions containing the hydrophobized pDNA in the oil phase to room temperature while stirring. The nanoparticles were characterized by particle sizing, zeta-potential, and TEM. Nanoparticles were challenged with serum nucleases to assess pDNA stability. In addition, the nanoparticles were coincubated with simulated biological media to assess their stability. In vitro hepatocyte transfection studies were completed with uncoated nanoparticles or nanoparticles coated with pullulan, a hepatocyte targeting ligand. In vivo biodistribution of the nanoparticles containing I-125 labeled pDNA was monitored 30 min after tail-vein injection to Balb/C mice. Depending on the hydrophobizing lipid agent employed, uniform pDNA-entrapped nanoparticles (100-160 nm in diameter) were engineered within minutes from warm O/W microemulsion precursors. The nanoparticles were negatively charged (-6 to -15 mV) and spherical. An anionic exchange column was used to separate unentrapped pDNA from nanoparticles. Gel permeation chromatography of pDNA-entrapped and serum-digested nanoparticles showed that the incorporation efficiency was approximately 30%. Free 'naked' pDNA was completely digested by serum nucleases while the entrapped pDNA remained intact. Moreover, in vitro transfection studies in Hep G2 cells showed that pullulan-coated nanoparticles resulted in enhanced luciferase expression, compared to both pDNA alone and uncoated nanoparticles. Preincubation of the cells with free pullulan inhibited the transfection. Finally, 30 min after tail vein injection to mice, only 16% of the 'naked' pDNA remained in the circulating blood compared to over 40% of the entrapped pDNA. Due to the apparent stability of these pDNA-entrapped nanoparticles in the blood, they may have potential for systemic gene therapy applications requiring cell and/or tissue-specific delivery.

Animals↗

PubMedDate not supplied

Engineering tumor-targeted gadolinium hexanedione nanoparticles for potential application in neutron capture therapy.

Microemulsions (oil-in-water) have been employed as templates to engineer nanoparticles containing high concentrations of gadolinium for potential application in neutron capture therapy of tumors. Gadolinium hexanedione (GdH), synthesized by complexation of Gd(3+) with 2,4-hexanedione, was used as the nanoparticle matrix alone or in combination with either emulsifying wax or PEG-400 monostearate. Solid nanoparticles (<125 nm size) were obtained by simple cooling of the microemulsions prepared at 60 degrees C to room temperature in one vessel. The feasibility of tumor targeting via folate receptors was studied. A folate ligand was synthesized by chemically linking folic acid to distearoylphosphatidylethanolamine (DSPE) via a poly(ethylene glycol) (PEG; MW 3350) spacer. To obtain folate-coated nanoparticles, the folate ligand (0.75% w/w to 15% w/w) was added to either the microemulsion templates at 60 degrees C or nanoparticle suspensions at 25 degrees C. Efficiencies of folate ligand attachment/adsorption to nanoparticle formulations were monitored by gel permeation chromatography. Cell uptake studies were carried out in KB cells (human nasopharyngeal epidermal carcinoma cell line), known to overexpress folate receptors. The uptake of folate-coated nanoparticles was about 10-fold higher than uncoated nanoparticles after 30 min at 37 degrees C. The uptake of folate-coated nanoparticles at 4 degrees C was 20-fold lower than the uptake at 37 degrees C and comparable to the uptake of uncoated nanoparticles at 37 degrees C. Folate-mediated endocytosis was further verified by the inhibition of folate-coated nanoparticles uptake by free folic acid. It was observed that folate-coated nanoparticles uptake decreased to approximately 2% of its initial value with the coincubation of 0.001 mM of free folic acid. The results suggested that these tumor-targeted nanoparticles containing high concentrations of Gd may have potential for neutron capture therapy.

Drug Delivery Systems↗

PubMedDate not supplied

Specific association of thiamine-coated gadolinium nanoparticles with human breast cancer cells expressing thiamine transporters.

Thiamine (vitamin B(1)) was investigated as a tumor-specific ligand for gadolinium nanoparticles. Solid nanoparticles containing gadolinium hexanedione (1.5 mg/mL) were engineered from oil-in-water microemulsion templates and coated with thiamine ligands. Thiamine ligands were synthesized by conjugating thiamine to either distearoylphosphatidylethanolamine (DSPE) or fluorescein via a poly(ethylene glycol) (PEG) spacer (Mw 3350). The efficiency of thiamine ligand attachment to nanoparticles was evaluated using gel permeation chromatography (GPC). Cell association studies were carried using a methotrexate-resistant breast cancer cell line, MTX(R)ZR75, transfected with thiamine transporter genes (THTR1 and THTR2). Thiamine-coated nanoparticle association with THTR1 and THTR2 cells was significantly greater than that with control breast cancer cells (MTX(R)ZR75 transfected with the empty expression vector pREP4) (p < 0.01; t-test). The nanoparticle cell association was significantly dependent on the extent of thiamine ligand coating on nanoparticles, expression of thiamine transporters in cells, temperature of incubation, and the concentration of competitive inhibitor (free thiamine). Further studies are warranted to assess the potential of the engineered thiamine-coated gadolinium (Gd) nanoparticles in neutron capture therapy of tumors.

Breast Neoplasms↗