Biomedical subjects

Russell J Mumper

Publications and source records attributed to Russell J Mumper.

At least 19 recordsLinked to original sources

PubMed2006

Preparation and characterization of nickel nanoparticles for binding to his-tag proteins and antigens.

PURPOSE: The purpose of these studies was to prepare nanoparticles (NPs) with a small amount of surface-chelated nickel for obtaining enhanced binding of histidine-tagged (his-tag) proteins compared to non-histidine-tagged protein binding to charged nanoparticles. MATERIALS AND METHODS: NPs were prepared from oil-in-water microemulsion precursors using emulsifying wax, 3 mM Brij 78 and 0.1 mM DOGS-NTA-Ni lipid (referred to as Ni-NPs). The amount of lipid entrapped in the NPs was quantitated by atomic emission spectroscopy (AES). The Ni-NPs were investigated for binding to two his-tag proteins, green fluorescent protein (GFP) and his-tag HIV-1 Gag p24. In vivo studies in mice were carried out to evaluate the immune responses obtained to his-tag Gag p24 bound to Ni-NPs. RESULTS: AES studies demonstrated that approximately 5% of the DOGS-NTA-Ni lipid used was entrapped in the NPs. The optimal binding ratio his-tag GFP and his-tag Gag p24 to Ni-NPs was found to be 1:33.7 and 1:35.4 w/w, respectively. This interaction was stable at 37 degrees C in PBS, pH 7.4 over 4 h and the interaction of his-tag GFP with the Ni-NPs was enhanced compared to control NPs prepared with no Ni on the surface (NTA-NPs). The in vivo studies demonstrated enhanced serum IgG and IgG2a responses to his-tag Gag p24 bound to Ni-NPs compared to protein adjuvanted with Alum or adsorbed on the surface of control NTA-NPs. CONCLUSIONS: Ni-NPs can be used to bind strongly to his-tag proteins. This system was demonstrated to have potential applications in vaccine delivery for enhancing immune responses to protein-based vaccines.

Antigens↗

PubMed2006

In-vivo efficacy of novel paclitaxel nanoparticles in paclitaxel-resistant human colorectal tumors.

Colloidal carriers have been shown to improve tumor therapy by increased drug delivery into tumor sites resulting directly from the enhanced permeability and retention effect (EPR). However, the clinical outcome of tumor therapy is often limited due to multidrug resistance. Several different types of resistance exist with expression of p-glycoprotein being the most commonly described. Paclitaxel entrapped in emulsifying wax nanoparticles (PX NPs) was shown to overcome drug resistance in a human colon adenocarcinoma cell line (HCT-15). In the present studies, the in-vivo efficacy of PX NPs in a HCT-15 mouse xenograft model was demonstrated. Significant inhibition in tumor growth was observed in mice receiving PX NPs treatment. Additionally, mice dosed with Taxol also demonstrated slower tumor growth; however, the efficacy of the Taxol treatment was shown in the in-vitro HUVEC model to be due to the antiangiogenic effect of paclitaxel. It was concluded that the enhanced efficacy of PX NPs over Taxol in the xenograft model was due to both overcoming paclitaxel resistance and an antiangiogenic effect.

Angiogenesis Inhibitors↗

PubMed2006

HIV-1 Tat-coated nanoparticles result in enhanced humoral immune responses and neutralizing antibodies compared to alum adjuvant.

HIV-1 Tat has been identified as an attractive target for vaccine development and is currently under investigation in clinical trials as both a therapeutic and preventative vaccine for HIV-1. It is well known that protein based vaccines produce poor immune responses by themselves and therefore require adjuvants to enhance immune responses. We have previously reported on the use of anionic nanoparticles (NPs) for enhancing cellular and humoral immune responses to Tat (1-72). The purpose of this study was to further evaluate the immune response of HIV-1 Tat (1-72) coated on anionic nanoparticles compared to alum using various doses of Tat (1-72). Nanoparticles were effective at generating comparable antibody titers at both 1 and 5 microg doses of Tat (1-72), whereas the antibody titers significantly decreased at the lower dose of Tat (1-72) using alum. Anti-sera from Tat (1-72) immunized mice reacted greatest to the N-terminal and basic regions of Tat, with the NP groups showing stronger reactivity to these regions compared to alum. Moreover, the anti-sera from all Tat (1-72) immunized groups contained Tat-neutralizing antibodies and were able to significantly inhibit Tat-mediated long terminal repeat (LTR) transactivation.

AIDS Vaccines↗

PubMed2005

Novel D-penicillamine carrying nanoparticles for metal chelation therapy in Alzheimer's and other CNS diseases.

Metal ions accumulate in the brain with aging and in several neurodegenerative diseases. Aside from the copper storage disease, Wilson's disease, recent attention has focused on the accumulation of zinc, copper and iron in the Alzheimer's disease (AD) brain and the accumulation of iron in Parkinson's disease. In particular, the parenchymal deposition of beta-amyloid (Abeta) and its interaction with metal ions has been postulated to play a role in the progression of AD. Thus, the strategy of lowering brain metal ions and targeting the interaction of Abeta peptide and metal ions through the administration of chelators has merit. Our recent finding that nanoparticle delivery systems can cross the blood-brain barrier has led us to investigate whether chelators delivered conjugated to nanoparticles could act to reverse metal ion induced protein precipitation. In the present studies, the Cu (I) chelator D-penicillamine was covalently conjugated to nanoparticles via a disulfide bond or a thioether bond. Nanoparticle-chelator conjugates were stable between pH 6-8 in aqueous suspension if stored at 4 degrees C, and did not aggregate when challenged with salts and serum. Release of D-penicillamine from the nanoparticles was achieved using reducing agents such as dithiothreitol (as a model for glutathione). Nanoparticles treated only under reducing conditions that released the conjugated D-penicillamine were able to effectively resolubilize copper-Abeta (1-42) aggregates. These results indicate that nanoparticles have potential to deliver D-penicillamine to the brain for the prevention of Abeta (1-42) accumulation, as well as to reduce metal ion accumulation in other CNS diseases.

Alzheimer Disease↗

PubMed2004

Paclitaxel nanoparticles for the potential treatment of brain tumors.

Despite the advances in tumor therapy, patients with primary brain tumors and brain metastases have a very poor prognosis. Low responses to chemotherapy are mainly attributed to impermeability of the blood-brain barrier to cytotoxic agents. Paclitaxel has been shown to be active against gliomas and various brain metastases. However, its use in treatment of brain tumors is limited due to low blood-brain barrier permeability and serious side effects associated with administration of the paclitaxel solvent, Cremophor EL. Lack of paclitaxel brain uptake is thought to be associated with the p-glycoprotein (p-gp) efflux transporter. In this work, paclitaxel (PX) was entrapped in novel cetyl alcohol/polysorbate nanoparticles. Paclitaxel nanoparticles (PX NPs) were characterized by means of size, short-term stability, drug entrapment efficiency, and release profile. The PX NP cytotoxicity profile was monitored using two different cell lines, U-118 and HCT-15. Brain uptake of PX NPs was evaluated using an in situ rat brain perfusion model. The results suggest that entrapment of paclitaxel in nanoparticles significantly increases the drug brain uptake and its toxicity toward p-glycoprotein expressing tumor cells. It was hypothesized that PX NPs could mask paclitaxel characteristics and thus limit its binding to p-gp, which consequently would lead to higher brain and tumor cell uptake of the otherwise effluxed drug.

Adjuvants, Pharmaceutic↗

PubMed2004

Strong T cell type-1 immune responses to HIV-1 Tat (1-72) protein-coated nanoparticles.

A significant emphasis has been placed on the development of adjuvants and/or delivery systems to improve both antibody production and cell-mediated immune responses. We previously reported on a novel anionic nanoparticle, which led to enhanced humoral and T helper type-1 (Th1) biased immune responses in mice when coated with cationized model antigen. Tat (1-72) is a conserved regulatory HIV-1 protein. It was hypothesized that HIV vaccine strategies employing Tat (1-72) may be a promising approach. Although previous reports have suggested that Tat (1-86) may be immunosuppressive, it was demonstrated in this present study that Tat (1-72) was not immunosuppressive when co-administered to mice with ovalbumin (OVA). Tat (1-72) was coated on novel anionic nanoparticles. BALB/c mice were immunized with Tat (5 microg)-coated nanoparticles (15 microg) by subcutaneous injection on days 0 and 14. Antibody and cytokine release were determined on day 28 and compared to Tat (5 microg) adjuvanted with Alum (15 microg) as a Th2 control, Tat (5 microg) adjuvanted with Lipid A (50 microg) as a Th1 control. Immunization of BALB/c mice with Tat-coated nanoparticles resulted in antibody levels (IgG and IgM) comparable to those elicited from Tat and Alum. However, Tat-coated nanoparticles led to a Th1 biased immune response. The IFN-gamma release from splenocytes with Tat-coated nanoparticles was comparable to that from mice immunized with Tat and Lipid A, and 3.3-fold greater than that from mice immunized with Tat and Alum. These studies warrant further investigation of these nanoparticles to enhance both antibody and cellular-based immune responses.

AIDS Vaccines↗

PubMed2004

Comparison of cell uptake, biodistribution and tumor retention of folate-coated and PEG-coated gadolinium nanoparticles in tumor-bearing mice.

The purpose of these studies was to compare the cell uptake, biodistribution and tumor retention of folate-coated and PEG-coated gadolinium (Gd) nanoparticles. Gd is a potential agent for neutron capture therapy (NCT) of tumors. Gd nanoparticles were engineered from oil-in-water microemulsion templates. To obtain folate-coated nanoparticles, a folate ligand [folic acid chemically linked to distearoylphosphatidylethanolamine (DSPE) via a PEG spacer MW 3350] was included in nanoparticle preparations. Similarly, control nanoparticles were coated with DSPE-PEG-MW 3350 (PEG-coated). Nanoparticles were characterized based on size, size distribution, morphology, biocompatibility and tumor cell uptake. In vivo studies were carried out in KB (human nasopharyngeal carcinoma) tumor-bearing athymic mice. Biodistribution and tumor retention studies were carried out at pre-determined time intervals after injection of nanoparticles (10 mg/kg). Gd nanoparticles did not aggregate platelets or activate neutrophils. The retention of nanoparticles in the blood 8, 16 and 24 h post-injection was 60%, 13% and 11% of the injected dose (ID), respectively. A maximum Gd tumor localization of 33+/-7 microg Gd/g was achieved. Both folate-coated and PEG-coated nanoparticles had comparable tumor accumulation. However, the cell uptake and tumor retention of folate-coated nanoparticles was significantly enhanced over PEG-coated nanoparticles. Thus, the benefits of folate ligand coating were to facilitate tumor cell internalization and retention of Gd-nanoparticles in the tumor tissue. The engineered nanoparticles may have potential in tumor-targeted delivery of Gd thereby enhancing the therapeutic success of NCT.

Animals↗

PubMed2004

Aqueous liquid scintillation counting with fluor-containing nanosuspensions.

A microemulsion comprised of water, Brij 78, pentanol and styrene into which PPO and bis-MSB had been dissolved was prepared. Polymerization of the styrene resulted in a suspension of fluor-containing polystyrene nanoparticles (<100 nm). After a concentration step, the aqueous nanosuspension was able to detect (14)C with counting efficiencies over 50% of those of a commercially available scintillation cocktail. Monte Carlo calculations demonstrated that the size and concentration of the nanoparticles were appropriate for optimum detection efficiency.

Carbon Radioisotopes↗

PubMed2004

Nanoparticle surface charges alter blood-brain barrier integrity and permeability.

PURPOSE: The blood-brain barrier (BBB) presents both a physical and electrostatic barrier to limit brain permeation of therapeutics. Previous work has demonstrated that nanoparticles (NPs) overcome the physical barrier, but there is little known regarding the effect of NP surface charge on BBB function. Therefore, this work evaluated: (1) effect of neutral, anionic and cationic charged NPs on BBB integrity and (2) NP brain permeability. METHODS: Emulsifying wax NPs were prepared from warm oil-in-water microemulsion precursors using neutral, anionic or cationic surfactants to provide the corresponding NP surface charge. NPs were characterized by particle size and zeta potential. BBB integrity and NP brain permeability were evaluated by in situ rat brain perfusion. RESULTS: Neutral NPs and low concentrations of anionic NPs were found to have no effect on BBB integrity, whereas, high concentrations of anionic NPs and cationic NPs disrupted the BBB. The brain uptake rates of anionic NPs at lower concentrations were superior to neutral or cationic formulations at the same concentrations. CONCLUSIONS: (1) Neutral NPs and low concentration anionic NPs can be utilized as colloidal drug carriers to brain, (2) cationic NPs have an immediate toxic effect at the BBB and (3) NP surface charges must be considered for toxicity and brain distribution profiles.

Animals↗

PubMed2003

Brain uptake of thiamine-coated nanoparticles.

Recently, a novel nanoparticle (NP) comprised of emulsifying wax and Brij 78 was shown to have significant brain uptake using the in-situ rat brain perfusion technique. To further these studies and to specifically target brain, we have incorporated thiamine as a surface ligand on the nanoparticles. Solid nanoparticles were prepared from oil-in-water microemulsion precursors. Nanoparticles were radiolabeled and a thiamine ligand (thiamine linked to distearoylphosphatidylethanolamine via a polyethylene glycol spacer) was coated on the surface of the nanoparticles. Initial experiments focused on assessing uptake of [3H]nanoparticles with and without thiamine surface ligands. Biodistribution nanoparticle studies were also carried out in BALB/c mice. The results showed: (1) the effectiveness of using microemulsions as precursors to engineer nanoparticles, (2) kinetic modeling for brain uptake of nanoparticles with and without the thiamine surface ligands, and (3) initial data suggesting mechanisms for nanoparticle brain entry. Comparison of NP brain uptake demonstrated that the thiamine-coated nanoparticle associated with the blood-brain barrier (BBB) thiamine transporter and had an increased K(in) between 45 and 120 s (thiamine coated NP 9.8 +/- 1.1 x 10(-3) ml/s/g versus uncoated NPs; 7.0 +/- 0.3 x 10(-3) ml/s/g). It was concluded that the thiamine ligand facilitated binding and/or association with blood-brain barrier thiamine transporters, which may be a viable mechanism for nanoparticle mediated brain drug delivery.

Animals↗

PubMed2003

Near-infrared spectroscopy for the determination of testosterone in thin-film composites.

More rapid, reproducible, and cost-effective methods to control product quality in the pharmaceutical industry continue to be a major emphasis, particularly with the FDA through its recent process analytical technologies (PAT) initiative. Many different methods have been used to determine the stability and content uniformity of a drug in various dosage forms; however, most of these methods include the destruction of the sample. Therefore, the development of nondestructive methods that allow the analysis of each individual dosage form has become the basis of much research. A new assay for the nondestructive determination of testosterone content in mucoadhesive bi-layer thin-film composites (TFCs) using near-infrared spectroscopy (NIR) was developed. Five sets of the circular films (n=5) with theoretical testosterone content of 0, 1, 2, 3, and 4 mg per 3/8th in. diameter disks were scanned in the near-infrared region of 1100-2500 nm to determine testosterone content. The NIR results were directly compared with those obtained using a previously developed ultraviolet assay for testosterone at 240 nm. Principal component regression (PCR) was performed to calibrate the NIR assay. This correlation produced r2=0.99 with a standard error of estimate (SEE)=0.18 mg, and a standard error of performance (SEP)=0.18 on cross validation with an equal number of samples (F test passed at P=0.05). Though the UV assay showed a slightly better r2 value, the NIR assay was much quicker, easier, and nondestructive. Therefore, the NIR assay may have significant potential for use in the quality control of pharmaceutical films containing drugs.

Acrylic Resins↗

PubMed2003

Intradermal immunization with novel plasmid DNA-coated nanoparticles via a needle-free injection device.

A high population of dendritic cells in the skin makes intradermal (ID) immunization an attractive route. We sought to further enhance immune responses from a previously reported novel nanoparticle-based DNA vaccine delivery system by administering the system intradermally into mouse skin using Biojector 2000, a needle-free jet injection device. Two mouse studies were carried out. Balb/C mice (n=5-6) were immunized on day 0, 7, and 14 by subcutaneous injection or via the Biojector 2000 with pDNA alone (CMV-beta-galactosidase, 5 micro g), pDNA-coated nanoparticles, or beta-galactosidase protein (10 micro g) adjuvanted with 'Alum' (15 micro g). On day 28, mice were sacrificed and specific serum IgG and IgA titer, in vitro cytokine release, and cell proliferation of isolated splenocytes were determined. Similar to previous reports, in both mouse studies, SC immunization with pDNA-coated nanoparticles led to over a log increase in specific serum IgG titer as compared to immunization with pDNA alone. For pDNA alone, jet and SC injection did not result in significant differences in IgG titer. In contrast, for pDNA-coated nanoparticles, jet injection led to as high as a 20-fold enhancement in IgG titer over SC injection. In addition, jet injection of pDNA-coated nanoparticles enhanced the IgG titer by more than 200-fold over jet injection of pDNA alone. Also, jet injection of pDNA-coated nanoparticles resulted in significantly enhanced specific serum IgA titer. For in vitro cytokine release, immunization with pDNA-coated nanoparticles by jet injection enhanced IFN-gamma and IL-4 release over pDNA alone by 6- and 5-fold, respectively. SC injection of pDNA-coated nanoparticles also resulted in enhanced IFN-gamma and IL-4 release over pDNA alone although with less magnitude. Finally, immunization with pDNA-coated nanoparticles, by both jet injection and SC injection, led to improved splenocyte proliferation over pDNA alone. In conclusion, a combination of a novel cationic nanoparticle-based DNA delivery system with ID jet injection led to enhanced antibody production, Th-1/Th-2 balanced cytokine release, and enhanced splenocyte proliferation.

Animals↗

PubMed2003

Influence of formulation parameters on gadolinium entrapment and tumor cell uptake using folate-coated nanoparticles.

Emulsifying wax and polyoxyl 2 stearyl ether (Brij 72) nanoparticles (2 mg/ml) containing high concentrations of gadolinium hexanedione (GdH) (0-3 mg) have been engineered from oil-in-water microemulsion templates. Solid nanoparticles were cured by cooling warm microemulsion templates (prepared at 55 degrees C) to room temperature in one vessel. Nanoparticles were characterized by transmission electron microscopy (TEM), photon correlation spectroscopy (PCS) and gel permeation chromatography (GPC). To obtain folate-coated nanoparticles, a folate ligand was added to either the microemulsion templates or nanoparticle suspensions at 25 degrees C. Since the concentration of Gd in the tumor is critical to the success of Gd-neutron capture therapy (NCT), the effects of various formulation factors on GdH entrapment in nanoparticles as well as tumor-targeting were studied. GdH entrapment in nanoparticles was affected mostly by the method of GdH incorporation and surfactant concentration used in preparing the microemulsion templates. Cell uptake studies were carried out in KB cells (human nasopharyngeal epidermal carcinoma cell line). The method of adding folate ligand to the formulations did not significantly affect nanoparticle cell uptake (P>0.11; t-test). However, the concentration of folate ligand added to nanoparticles had the greatest influence on nanoparticle uptake (P<0.01; t-test). The results showed that GdH entrapment and cell uptake were optimized and suggested that engineered folate-coated nanoparticles may serve as effective carrier systems for Gd-NCT of tumors.

Chemistry, Pharmaceutical↗

PubMed2003

The effect of co-administration of adjuvants with a nanoparticle-based genetic vaccine delivery system on the resulting immune responses.

Previously, we reported on a novel cationic nanoparticle-based DNA vaccine delivery system. In the present studies, the effects of co-administration of two well-known adjuvants, cholera toxin (CT) and lipid A (LA), with plasmid DNA (pDNA)-coated nanoparticles were investigated. Balb/C mice (n=6) were immunized with either pDNA alone (cytomegalovirus-beta-galactosidase, 5 microg) or pDNA-coated nanoparticles with either 0 or 50 microg of LA on days 0, 7, and 14 subcutaneously (s.c.), or topically on shaved skin with either pDNA (5 microg) alone or pDNA-coated nanoparticles with 0, 10, or 100 microg of CT on days 0, 6, 21, and 35. Mice were sacrificed on day 28 or day 45. Serum IgG titer, in vitro cytokine release and cell proliferation of the isolated splenocytes were determined. By the topical route, immunization of mice with 'naked' pDNA together with 10 and 100 microg of CT significantly enhanced the antigen-specific serum IgG titer by four- and 20-fold, respectively, compared to immunization with pDNA alone. Moreover, co-administration of 100 microg CT with the pDNA-nanoparticles enhanced the IgG titer by more than 300-fold over immunization with 'naked' pDNA alone with no CT. In vitro interferon-gamma (IFN)-gamma release from splenocytes isolated from mice immunized with pDNA-coated nanoparticles with CT (100 microg) was increased by three-fold over immunization with pDNA-nanoparticles without CT. Similarly, in vitro IFN-gamma release from splenocytes isolated from mice immunized with 'naked' pDNA with CT (100 microg) was increased by two-fold over immunization with 'naked' pDNA without CT. Finally, pDNA-coated nanoparticles adjuvanted with 10 microg CT resulted in the strongest splenocyte proliferation. By the s.c. route, co-administration of LA (50 microg) with pDNA resulted in more than 16-fold enhancement in IgG titer over immunization with 'naked' pDNA alone. Immunization with pDNA-coated nanoparticles with LA (50 microg) led to 16-fold enhancement in specific serum IgG titer over immunization with pDNA-coated nanoparticles with no LA, and more than 250-fold enhancement over immunization with 'naked' pDNA alone with no LA. Moreover, in vitro IFN-gamma release and proliferation by splenocytes isolated from LA co-immunized mice was also significantly enhanced. In conclusion, CT (topical) and LA (s.c.) are potential adjuvants to further enhance immune responses using a novel cationic nanoparticle-based DNA vaccine delivery system.

Adjuvants, Immunologic↗

PubMed2003

Genetic immunization by jet injection of targeted pDNA-coated nanoparticles.

Genetic immunization strategies have largely focused on the use of "naked" plasmid DNA or the gene gun. However, there remains a clear need to further improve the efficiency and/or cost of potential DNA vaccines. The theoretical basis of our research is to rationally design genetic immunization methodologies for nanoparticle-based delivery systems of plasmid DNA, perhaps in combination with already commercially available needle-free devices, such as the Biojector 2000. These methodologies may both reduce the dose of pDNA required and enhance the breadth and depth of protective immune responses (i.e., humoral and cellular). The purpose of this article is to provide detailed experimental methods to (1) engineer and characterize pDNA-coated cationic nanoparticles (<100nm) directly from oil-in-water microemulsion precursors and (2) enhance both the breadth and depth of immune responses after immunization of mice with pDNA-coated nanoparticles by different routes of administration, including intradermal, using a needle-free jet injection device.

Animals↗

PubMed2003

Novel ethanol-in-fluorocarbon microemulsions for topical genetic immunization.

PURPOSE: Traditionally, vaccines have been administered by needle injection. Topical immunization through the intact skin with either protein- or DNA-based vaccines has attracted much attention recently. We sought to enhance the immune responses induced by DNA-based vaccines after topical application by developing novel ethanol-in-fluorocarbon (E/F) microemulsion systems to aid in the delivery of plasmid DNA (pDNA). METHODS: Ten different fluorosurfactants were selected or synthesized and screened by pseudo-phase-diagram construction for their ability to form E/F microemulsions. Plasmid DNA was successfully incorporated into E/F microemulsions using several different fluorosurfactants and perfluorooctyl bromide as the continuous fluorocarbon phase. For several reasons, Zonyl FSN-100 (an ethoxylated nonionic fluorosurfactant) was selected for further studies. In vivo studies were performed in mice to assess pDNA expression in skin and immunologic responses after topical application of this system using a luciferase-encoding plasmid (CMV-luciferase) and a CMV-beta-galactosidase-encoding plasmid, respectively. RESULTS: Plasmid DNA incorporated into E/F microemulsion using FSN-100 as the surfactant was found to be stable. After topical application of this E/F microemulsion system, significant enhancements in luciferase expression and antibody and T-helper type-1 biased immune responses were observed relative to those of "naked" pDNA in saline or ethanol. For example, with the E/F microemulsion system, the specific serum IgG and IgA titers were increased by 45-fold and over 1000-fold, respectively. CONCLUSION: A novel fluorocarbon-based microemulsion system for potential DNA vaccine delivery was developed.

Administration, Topical↗

PubMed2003

In vivo and in vitro assessment of baseline blood-brain barrier parameters in the presence of novel nanoparticles.

PURPOSE: Nanoparticles have advantage as CNS drug delivery vehicles given they disguise drug permeation limiting characteristics. Conflicting toxicological data, however, is published with regard to blood-brain barrier integrity and gross mortality. METHODS: To address this issue two novel nanoparticle types: "emulsifying wax/Brij 78" and "Brij 72/Tween 80 nanoparticles were evaluated in vivo for effect on cerebral perfusion flow, barrier integrity, and permeability using the in situ brain perfusion technique. Additional evaluation was completed in vitro using bovine brain microvessel endothelial cells for effect on integrity, permeability, cationic transport interactions, and tight junction protein expression. RESULTS: In the presence of either nanoparticle formulation, no overall significant differences were observed for cerebral perfusion flow in vivo. Furthermore, observed in vitro and in vivo data showed no statistical changes in barrier integrity, membrane permeability, or facilitated choline transport. Western blot analyses of occludin and claudin-1 confirmed no protein expression changes with incubation of either nanoparticle. CONCLUSIONS: The nanoparticle formulations appear to have no effect on primary BBB parameters in established in vitro and in vivo blood-brain barrier models.

Animals↗

PubMed2003

In situ blood-brain barrier transport of nanoparticles.

PURPOSE: Two novel types of nanoparticles were evaluated as poten tial carriers for drugs across the blood-brain barrier (BBB). METHODS: Nanoparticles were composed of biocompatible materials including emulsifying wax (E. Wax) or Brij 72. Brij 78 and Tween 80 were used as surfactants for E. Wax nanoparticles (E78 NPs) and Brij 72 nanoparticles (E72 NPs), respectively. Both nanoparticle formulations were prepared from warm microemulsion precursors usin melted E. Wax or Brij 72 as the oil phase. Nanoparticles were radio-labeled by entrapment of [3H]cetyl alcohol, and entrapment efficiency and release of radiolabel were evaluated. The transport of E78 and E72 NPs across the BBB was measured by an in situ rat brai perfusion method. RESULTS: Both formulations were successfully radiolabeled by entrapment of [3H]cetyl alcohol; -98% of radiolabel remained associated with nanoparticles at experimental conditions. The transfer rate (Kin) of E78 NPs from perfusion fluid into the brain was 4.1 +/- 0.5 x 10(-3) ml/s/g, and the permeability-surface area product (PA) was 4.3 +/- 0.7 x 10(-3) ml/s/g. The values for Kin and PA for E72 NPs were 5.7 +/- 1.1 x 10(-3) ml/s/g and 6.1 +/- 1.4 x 10(-3) ml/s/g, respectively. CONCLUSIONS: For both nanoparticle types, statistically significant uptake was observed compared to [14C]sucrose, suggesting central nervous system uptake of nanoparticles. The mechanism underlying th nanoparticle brain uptake has yet to be fully understood.

Animals↗