Surface Analysis of PEGylated Nano-Shields on Nanoparticles Installed by Hydrophobic Anchors

Purpose

This work describes a method for functionalisation of nanoparticle surfaces with hydrophilic “nano-shields” and the application of advanced surface characterisation to determine PEG amount and accumulation at the outmost 10 nm surface that is the predominant factor in determining protein and cellular interactions.

Methods

Poly(lactic-co-glycolic acid) (PLGA) nanoparticles were prepared with a hydrophilic PEGylated “nano-shield” inserted at different levels by hydrophobic anchoring using either a phospholipid-PEG conjugate or the copolymer PLGA-block-PEG by an emulsification/diffusion method. Surface and bulk analysis was performed including X-ray photoelectron spectroscopy (XPS), nuclear magnetic resonance spectroscopy (NMR) and zeta potential. Cellular uptake was investigated in RAW 264.7 macrophages by flow cytometry.

Results

Sub-micron nanoparticles were formed and the combination of (NMR) and XPS revealed increasing PEG levels at the particle surface at higher PLGA-b-PEG copolymer levels. Reduced cellular interaction with RAW 264.7 cells was demonstrated that correlated with greater surface presentation of PEG.

Conclusion

This work demonstrates a versatile procedure for decorating nanoparticle surfaces with hydrophilic “nano-shields”. XPS in combination with NMR enabled precise determination of PEG at the outmost surface to predict and optimize the biological performance of nanoparticle-based drug delivery.     

Nanoparticles Based on a Hydrophilic Polyester with a Sheddable PEG Coating for Protein Delivery

Purpose

To investigate the effect of polyethylene glycol (PEG) in nanoparticles based on blends of hydroxylated aliphatic polyester, poly(D,L-lactic-co-glycolic-co-hydroxymethyl glycolic acid) (PLGHMGA) and PEG-PLGHMGA block copolymers on their degradation and release behavior.

Methods

Protein-loaded nanoparticles were prepared with blends of varying ratios of PEG-PLGHMGA (molecular weight of PEG 2,000 and 5,000 Da) and PLGHMGA, by a double emulsion method with or without using poly(vinyl alcohol) (PVA) as surfactant. Bovine serum albumin and lysozyme were used as model proteins.

Results

PEGylated particles prepared without PVA had a zeta potential ranging from ~ ?3 to ~?35 mV and size ranging from ~200 to ~600 nm that were significantly dependent on the content and type of PEG-block copolymer. The encapsulation efficiency of the two proteins however was very low (<30%) and the particles rapidly released their content in a few days. In contrast, all formulations prepared with PVA showed almost similar particle properties (size: ~250 nm, zeta potential: ~?1 mV), while loading efficiency for both model proteins was rather high (80–90%). Unexpectedly, independent of the type of formulation, the nanoparticles had nearly the same release and degradation characteristics. NMR analysis showed almost a complete removal of PEG in 5 days which explains these marginal differences.

Conclusions

Protein release and particle degradation are not substantially influenced by the content of PEG, likely because of the fast shedding of the PEG blocks. These PEG shedding particles are interesting system for intracellular delivery of drugs.     

Is an Alternative Drug Delivery System Needed for Docetaxel? The Role of Controlling Epimerization in Formulations and Beyond

Purpose

The presence of 7-epidocetaxel in docetaxel injection and in vivo epimerisation has been reported to be the cause for development of tumor resistance to chemotherapy including docetaxel by inducing tumor cell protein cytochrome P450 1B1. The objective of this study was to determine systemic toxicity of Taxotere® containing 10% 7-epidocetaxel and to develop PEGylated liposomal injection that could resist epimerization in vivo. Another need for PEGylated liposomal delivery of docetaxel is to avoid reported hypersensitivity reactions of marketed products like Taxotere® and Duopafei® containing high concentration of tween-80.

Methods

The PEGylated liposomes loaded with docetaxel were prepared using thin film hydration method. The in vivo toxicity of Taxotere® containing 10% 7-epimer was studied in B16F10 experimental metastasis model.

Results

B16F10 experimental metastasis model using C57BL/6 mice injected with Taxotere® containing 10% 7-epimer showed higher weight loss as compared to Taxotere® containing no epimer at single dose of 40 mg/kg indicating higher systemic toxicity. Incubation of PEGylated liposomes with phosphate buffer saline (pH 7.4) containing 0.1% w/v Tween-80 for 48 h showed better resistance to docetaxel degradation when compared with Taxotere® injection indicating better in vivo stability of liposomal docetaxel. In addition, PEGylated liposomes showed enhanced in vitro cytotoxicity, against A549 and B16F10 cells, than Taxotere®.

Conclusion

We can therefore expect less in vivo conversion of liposomal loaded docetaxel into 7-epimer, more passive targeting to tumor tissues, decreased 7-epimer induced systemic toxicity and tumor resistance to chemotherapy compared to Taxotere®. Further in vivo studies are needed to ascertain these facts.     

Squalene-Containing Nanostructured Lipid Carriers Promote Percutaneous Absorption and Hair Follicle Targeting of Diphencyprone for Treating Alopecia Areata

Purpose

Diphencyprone (DPCP) is a therapeutic agent for treating alopecia areata. To improve skin absorption and follicular targeting nanostructured lipid carriers (NLCs) were developed.

Methods

Nanoparticles were characterized by size, zeta potential, molecular environment, differential scanning calorimetry (DSC), and nuclear magnetic resonance (NMR). In vitro and in vivo skin absorption experiments were performed. Fluorescence and confocal microscopes for imaging skin distribution were used.

Results

NLCs with different designs were 208?~?265 nm with ?>?77% DPCP encapsulation. NLCs incorporating a cationic surfactant or more soybean phosphatidylcholine (SPC) showed higher lipophilicity compared to typical NLCs by Nile red emission. All NLCs tested revealed controlled DPCP release; burst release was observed for control. The formulation with more SPC provided 275 μg/g DPCP skin retention, which was greater than control and other NLCs. Intersubject deviation was reduced after DPCP loading into NLCs. Cyanoacrylate skin biopsy demonstrated greater follicular deposition for NLCs with more SPC compared to control. Cationic NLCs but not typical or SPC-containing carriers were largely internalized into keratinocytes. In vivo skin retention of NLCs with more SPC was higher than free control. Confocal imaging confirmed localization of NLCs in follicles and intercellular lipids of stratum corneum.

Conclusions

This work encourages further investigation of DPCP absorption using NLCs with a specific formulation design.     

Development of 2D and 3D Mucus Models and Their Interactions with Mucus-Penetrating Paclitaxel-Loaded Lipid Nanocapsules

Purpose

To study, diffusion through mucus (3D model) of different formulations of paclitaxel loaded lipid nanocapsules (Ptx-LNCs), to interpret the results in the light of LNC behavior at air-mucus interface (2D model).

Methods

LNC surface properties were modified with chitosan or poly(ethylene glycol) (PEG) coatings of different size (PEG 2,000 to 5,000 Da) and surface charges. LNC diffusion through 446 μm pig intestinal mucus layer was studied using Transwell^®. LNCs were spread at the air-water-mucus interface then interfacial pressure and area changes were monitored and the efficiency of triglyceride (TG) inclusion was determined.

Results

Ptx-LNCs of surface charges ranging from ?35.7 to +25.3 mV were obtained with sizes between 56.2 and 75.1 nm. The diffusion of paclitaxel in mucus was improved after encapsulation in neutral or positively charged particles (p?<?0.05 vs Taxol^®). No significative difference was observed in the 2,000–5,000 PEG length for diffusion both on the 2D or 3D models. On 2D model positive or neutral LNCs interacted less with mucus. Highest efficiency of TG inclusion was observed for particles with smallest PEG length.

Conclusions

The results obtained with 2D and 3D model allowed us to select the best candidates for in vivo studies (neutral or positive LNCs with smaller PEG length).     

PEGylated Multi-Walled Carbon Nanotubes for Encapsulation and Sustained Release of Oxaliplatin

Purpose

To develop PEGylated multi-walled carbon nanotubes as a sustained release drug delivery system.

Methods

Oxaliplatin was incorporated into inner cavity of PEGylated multi-walled carbon nanotubes (MWCNT-PEG) using nano-extraction. Oxaliplatin release rates from MWCNT-PEG-Oxaliplatin were investigated using dialysis tubing. Cytotoxicity of oxaliplatin, MWCNT-Oxaliplatin and MWCNT-PEG-Oxaliplatin were evaluated in HT29 cell by MTT assay, Pt-DNA adducts formation, γ-H2AX formation and cell apoptosis assay.

Results

Loading of oxaliplatin into MWCNT-PEG was ~43.6%. Sustained release occurred to MWCNT-PEG-Oxaliplatin, with only 34% of oxaliplatin released into medium within 6 h. In MTT assay, MWCNT-PEG-Oxaliplatin showed slightly decreased cytotoxic effect when cell viability was assessed at 12 and 24 h. A drastic increase of cytotoxicity was found when cell viability was assessed at 48 and 96 h. Pt-DNA adducts formation, γ-H2AX formation and cell apoptosis assay results showed the same trend as the MTT assay, suggesting sustained-release for MWCNT-Oxaliplatin and MWCNT-PEG-Oxaliplatin formulations.

Conclusions

PEGylated multi-walled carbon nanotubes can be used as sustained release drug delivery system, thus remarkably improving cytotoxicity of oxaliplatin on HT-29 cells.     

Radioiodinated Hypericin: Its Biodistribution, Necrosis Avidity and Therapeutic Efficacy are Influenced by Formulation

Purpose

To study whether formulation influences biodistribution, necrosis avidity and tumoricidal effects of the radioiodinated hypericin, a necrosis avid agent for a dual-targeting anticancer radiotherapy.

Methods

Iodine-123- and 131-labeled hypericin (¹²³I-Hyp and ¹³¹I-Hyp) were prepared with Iodogen as oxidant, and formulated in dimethyl sulfoxide (DMSO)/PEG400 (polyethylene glycol 400)/water (25/60/15, v/v/v) or DMSO/saline (20:80, v/v). The formulations with excessive Hyp were optically characterized. Biodistribution, necrosis avidity and tumoricidal effects were studied in rats (n?=?42) without and with reperfused liver infarction and implanted rhabdomyosarcomas (R1). To induce tumor necrosis, R1-rats were pre-treated with a vascular disrupting agent. Magnetic resonance imaging, tissue-gamma counting, autoradiography and histology were used.

Results

The two formulations differed significantly in fluorescence and precipitation. ¹²³I-Hyp/Hyp in DMSO/PEG400/water exhibited high uptake in necrosis but lower concentration in the lung, spleen and liver (p?<?0.01). Tumor volumes of 0.9?±?0.3 cm³ with high radioactivity (3.1?±?0.3% ID/g) were detected 6 days post-treatment. By contrast, ¹³¹I-Hyp/Hypin DMSO/saline showed low uptake in necrosis but high retention in the spleen and liver (p?<?0.01). Tumor volumes reached 2.6?±?0.7 cm³ with low tracer accumulation (0.1?±?0.04%ID/g).

Conclusions

The formulation of radioiodinated hypericin/hypericin appears crucial for its physical property, biodistribution, necrosis avidity and tumoricidal effects.     

Temozolomide Delivery to Tumor Cells by a Multifunctional Nano Vehicle Based on Poly(β-L-malic acid)

Purpose

Temozolomide (TMZ) is a pro-drug releasing a DNA alkylating agent that is the most effective drug to treat glial tumors when combined with radiation. TMZ is toxic, and therapeutic dosages are limited by severe side effects. Targeted delivery is thus needed to improve efficiency and reduce non-tumor tissue toxicity.

Methods

Multifunctional targetable nanoconjugates of TMZ hydrazide were synthesized using poly(β-L-malic acid) platform, which contained a targeting monoclonal antibody to transferrin receptor (TfR), trileucine (LLL), for pH-dependent endosomal membrane disruption, and PEG for protection.

Results

The water-soluble TMZ nanoconjugates had hydrodynamic diameters in the range of 6.5 to 14.8 nm and ζ potentials in the range of ?6.3 to ?17.7 mV. Fifty percent degradation in human plasma was observed in 40 h at 37°C. TMZ conjugated with polymer had a half-life of 5–7 h, compared with 1.8 h for free TMZ. The strongest reduction of human brain and breast cancer cell viability was obtained by versions of TMZ nanoconjugates containing LLL and anti-TfR antibody. TMZ-resistant cancer cell lines were sensitive to TMZ nanoconjugate treatment.

Conclusions

TMZ-polymer nanoconjugates entered the tumor cells by receptor-mediated endocytosis, effectively reduced cancer cell viability, and can potentially be used for targeted tumor treatment.     

Lysozyme Release and Polymer Erosion Behavior of Injectable Implants Prepared from PLGA-PEG Block Copolymers and PLGA/PLGA-PEG Blends

Purpose

We evaluated the controlled release of lysozyme from various poly(D,L-lactic-co-glycolic acid) (PLGA) 50/50-polyethylene glycol (PEG) block copolymers relative to PLGA 50/50.

Methods

Lysozyme was encapsulated in cylindrical implants (0.8 mm diameter) by a solvent extrusion method. Release studies were conducted in phosphate buffered saline +0.02% Tween 80 (PBST) at 37°C. Lysozyme activity was measured by a fluorescence-based assay. Implant erosion was evaluated by kinetics of polymer molecular weight decline, water uptake, and mass loss.

Results

Lysozyme release from an AB15 di-block copolymer (15% 5 kDa PEG, PLGA 28 kDa) was very fast, whereas an AB10 di-block copolymer (with 10% 5 kDa PEG, PLGA 45 kDa) and ABA10 tri-block copolymer (with 10% 6 kDa PEG, PLGA 27 kDa) showed release profiles similar to PLGA. We achieved continuous lysozyme release for up to 4 weeks from AB10 and ABA10 by lysozyme co-encapsulation with the pore-forming and acid-neutralizing MgCO₃, and from AB15 by co-encapsulation of MgCO₃ and blending AB15 with PLGA. Lysozyme activity was mostly recovered during 4 weeks.

Conclusions

These block co-polymers may have utility either alone or as PLGA blends for the controlled release of proteins.     

Optimization of Acoustic Liposomes for Improved In Vitro and In Vivo Stability

Purpose

Liposomes encapsulating perfluoropropane gas, termed acoustic liposomes (ALs), which can serve both for ultrasound (US) imaging and US-mediated gene delivery, have been reported. However, the echogenicity of ALs decreases within minutes in vivo due to gas diffusion and leakage, hindering time-consuming procedures such as contrast-enhanced 3D US imaging and raising the need for improvement of their stability.

Methods

The stability of ALs preparations incorporating increasing ratios of anionic / unsaturated phospholipids, polyethylene glycol (PEG)ylated phospholipid and cholesterol was investigated by measurement of their reflectivity over time using a high-frequency US imaging system, both in vitro and in vivo.

Results

The retention of echogenicity of ALs in vitro is enhanced with increasing molar ratios of PEGylated lipids. Addition of 10 molar percent of an anionic phospholipid resulted in a 31% longer half-life, while cholesterol had the opposite effect. Assessment of the stability of an optimized composition showed a more than 2-fold increase of the detection half-life in mice.

Conclusions

Presence of a PEG coating not only serves to provide ??stealth?? properties in vivo, but also contributes to the retention of the encapsulated gas. The optimized ALs reported here can be used as a contrast agent for lengthier imaging procedures.     

On-Command Drug Release from Nanochains Inhibits Growth of Breast Tumors

Purpose

To evaluate the ability of radiofrequency (RF)-triggered drug release from a multicomponent chain-shaped nanoparticle to inhibit the growth of an aggressive breast tumor.

Methods

A two-step solid phase chemistry was employed to synthesize doxorubicin-loaded nanochains, which were composed of three iron oxide nanospheres and one doxorubicin-loaded liposome assembled in a 100-nm-long linear nanochain. The nanochains were tested in the 4T1-Luc-GFP orthotopic mouse model, which is a highly aggressive breast cancer model. The 4T1-Luc-GFP cell line stably expresses firefly luciferase, which allowed the non-invasive in vivo imaging of tumor response to the treatment using bioluminescence imaging (BLI).

Results

Longitudinal BLI imaging showed that a single nanochain treatment followed by application of RF resulted in an at least 100-fold lower BLI signal compared to the groups treated with nanochains (without RF) or free doxorubicin followed by RF. A statistically significant increase in survival time of the nanochain-treated animals followed by RF (64.3 days) was observed when compared to the nanochain-treated group without RF (35.7 days), free doxorubicin-treated group followed by RF (38.5 days), and the untreated group (30.5 days; n?=?5 animals per group).

Conclusions

These studies showed that the combination of RF and nanochains has the potential to effectively treat highly aggressive cancers and prolong survival.     

Synergistic effects between CA1 mu opioid and dopamine D1-like receptors in impaired passive avoidance performance induced by hepatic encephalopathy in mice

Background and aim

Numerous investigations have indicated that hepatic encephalopathy (HE) alters the levels of various neurotransmitters. However, comprehensive data regarding the effects of CA1 opioidergic and dopaminergic (DAergic) systems on HE-induced amnesia are still lacking.

Methods

Following intra-dorsal hippocampal (CA1) injection of mu opioid and dopamine D1- and D2-like receptors antagonists in male mice, one-trial step-down and hole-board paradigms were used to assess memory and exploratory behaviors, respectively.

Results

Our data demonstrated that HE impairs memory 24 days after bile duct ligation (BDL). Furthermore, while the higher dose of DA D1-like receptor antagonist (SCH23390, 0.5 μg/mouse) induced amnesia and anxiogenic-like behaviors, mu receptor antagonist (naloxone: 0.0125, 0.025 and 0.05 μg/mouse) and DA D2-like receptor antagonist (sulpiride: 0.0625, 0.125 and 0.25 μg/mouse) by themselves, could not exert an effect on memory performance in passive avoidance task. On the other hand, pre-test injection of all drugs reversed the HE-induced amnesia 24 days after BDL, while having no effect on exploratory behaviors. Pre-test co-administration of the subthreshold dose SCH23390 (0.25 μg/mouse) and sulpiride (0.0625 μg/mouse) or naloxone (0.0125 μg/mouse) could likewise reverse the BDL-induced amnesia. However, when the subthreshold sulpiride plus naloxone were co-administered, BDL-induced amnesia was not blocked.

Conclusions

Memory performance is impaired 24 days post BDL and CA1 mu opioid and DA D1-like receptors antagonist synergistic effects are likely involved in this phenomenon     

CD44 Targeting Magnetic Glyconanoparticles for Atherosclerotic Plaque Imaging

Purpose

The cell surface adhesion molecule CD44 plays important roles in the initiation and development of atherosclerotic plaques. We aim to develop nanoparticles that can selectively target CD44 for the non-invasive detection of atherosclerotic plaques by magnetic resonance imaging.

Methods

Magnetic glyconanoparticles with hyaluronan immobilized on the surface have been prepared. The binding of these nanoparticles with CD44 was evaluated in vitro by enzyme linked immunosorbent assay, flow cytometry and confocal microscopy. In vivo magnetic resonance imaging of plaques was performed on an atherosclerotic rabbit model.

Results

The magnetic glyconanoparticles can selectively bind CD44. In T2* weighted magnetic resonance images acquired in vivo, significant contrast changes in aorta walls were observed with a very low dose of the magnetic nanoparticles, allowing the detection of atherosclerotic plaques. Furthermore, imaging could be performed without significant delay after probe administration. The selectivity of hyaluronan nanoparticles in plaque imaging was established by several control experiments.

Conclusions

Magnetic nanoparticles bearing surface hyaluronan enabled the imaging of atherosclerotic plaques in vivo by magnetic resonance imaging. The low dose of nanoparticles required, the possibility to image without much delay and the high biocompatibility are the advantages of these nanoparticles as contrast agents for plaque imaging.     

EphA2 Targeting Pegylated Nanocarrier Drug Delivery System for Treatment of Lung Cancer

Purpose

Evaluation of tumor targeting pegylated EphA2 peptide coated nanoparticles (ENDDs) of a novel anticancer agent DIM-C-pPhC₆H₅ (DIM-P) and Docetaxel (DOC) and investigate its antitumor activity and potential for treatment of lung cancer.

Methods

Nanoparticles were prepared with DIM-P and DOC (NDDs) using Nano-DeBEE. ENDDs were prepared by conjugating NDDs with 6His-PEG2K-EphA2 peptide and characterized for physicochemical properties, binding assay, cytotoxicity, cellular uptake studies, drug release and pharmacokinetic parameters. Anti-tumor activity of ENDDs was evaluated using a metastatic H1650 and orthotopic A549 tumor models in nude mice and tumor tissue were analyzed by RT-PCR and immunohistochemistry.

Results

Particle size and entrapment efficiency of ENDDs were 197?±?21 nm and 95?±?2%. ENDDs showed 32.5?±?3.5% more cellular uptake than NDDs in tumor cells. ENDDs showed 23?±?3% and 26?±?4% more tumor reduction compared to NDDs in metastatic and orthotopic tumor models, respectively. In-vivo imaging studies using the Care stream MX FX Pro system showed (p?Conclusions The results emanating from these studies demonstrate anti-cancer potential of DIM-P and the role of ENDDs as effective tumor targeting drug delivery systems for lung cancer treatment.     

Folate and TAT Peptide Co-Modified Liposomes Exhibit Receptor-Dependent Highly Efficient Intracellular Transport of Payload In Vitro and In Vivo

Purpose

Using different chain lengths of PEG as linkers to develop a novel folate (FA) and TAT peptide co-modified doxorubicin (DOX)-loaded liposome (FA/TAT-LP-DOX) and evaluate its potential for tumor targeted intracellular drug delivery.

Methods

FA/TAT-LP-DOX was prepared by pH gradient method and post-insertion method and the optimal ligand density was screened by MTT assay. In vitro evaluation was systematically performed through cytotoxicity assay, cellular uptake studies, subcellular localization and cellular uptake mechanism in folate receptor (FR) over-expressing KB tumor cells. In vivo tumor targeted delivery of FA/TAT-LP-DOX was also studied by in vivo fluorescence imaging in a murine KB xenograft model.

Results

The particle size and zeta potential determination indicated that FA and TAT were successfully inserted into the liposome and cationic TAT peptide was completely shielded. With the optimal ligand density (5% of FA and 2.5% TAT), the FA/TAT-LP-DOX exhibited improved cytotoxity and cellular uptake efficiency compared with its single-ligand counterparts (FA-LP-DOX and PEG/TAT-LP-DOX). Competitive inhibition and uptake mechanism experiments revealed that FA and TAT peptide played a synergistic effect in facilitating intracellular transport of the liposome, and association between FA and FA receptors activated this transport process. In vivo imaging further demonstrated the superiority of FA/TAT-LP in tumor targeting and accumulation.

Conclusions

Folate and TAT peptide co-modified liposome using different chain lengths of PEG as linkers may provide a useful strategy for specific and efficient intracellular drug delivery.     

Block Copolymer Cross-Linked Nanoassemblies Improve Particle Stability and Biocompatibility of Superparamagnetic Iron Oxide Nanoparticles

Purpose

To develop cross-linked nanoassemblies (CNAs) as carriers for superparamagnetic iron oxide nanoparticles (IONPs).

Methods

Ferric and ferrous ions were co-precipitated inside core-shell type nanoparticles prepared by cross-linking poly(ethylene glycol)-poly(aspartate) block copolymers to prepare CNAs entrapping Fe₃O₄ IONPs (CNA-IONPs). Particle stability and biocompatibility of CNA-IONPs were characterized in comparison to citrate-coated Fe₃O₄ IONPs (Citrate-IONPs).

Results

CNA-IONPs, approximately 30 nm in diameter, showed no precipitation in water, PBS, or a cell culture medium after 3 or 30 h, at 22, 37, and 43°C, and 1, 2.5, and 5 mg/mL, whereas Citrate-IONPs agglomerated rapidly (> 400 nm) in all aqueous media tested. No cytotoxicity was observed in a mouse brain endothelial-derived cell line (bEnd.3) exposed to CNA-IONPs up to 10 mg/mL for 30 h. Citrate-IONPs (> 0.05 mg/mL) reduced cell viability after 3 h. CNA-IONPs retained the superparamagnetic properties of entrapped IONPs, enhancing T2-weighted magnetic resonance images (MRI) at 0.02 mg/mL, and generating heat at a mild hyperthermic level (40?~?42°C) with an alternating magnetic field (AMF).

Conclusion

Compared to citric acid coating, CNAs with a cross-linked anionic core improved particle stability and biocompatibility of IONPs, which would be beneficial for future MRI and AMF-induced remote hyperthermia applications.     

Quantiosomes as a Multimodal Nanocarrier for Integrating Bioimaging and Carboplatin Delivery

Purpose

Here we report the development of quantiosomes, niosomes formed from Span 60, cholesterol, and quantum dots (QDs), for achieving sensitive bioimaging and anticancer drug delivery.

Methods

The nanocarriers were further modified by incorporating soy phosphatidylcholine (SPC), polyethylene glycol (PEG), or cationic surfactant to display different efficiencies. Carboplatin was used as the model drug. The cellular uptake, cytotoxicity, and migration inhibition of quantiosomes for treating melanoma cells were described. Finally, intratumoral carboplatin accumulation and in-vivo bioimaging were examined.

Results

The average diameters of quantiosomes ranged between 151 and 173 nm, depending on the composition selected. Approximately 50% of the drug was entrapped in quantiosomes. Electron microscopy confirmed the bilayer structure of quantiosomes and the presence of QDs in the vesicular surface. The nanodispersions showed a significant internalization into cells, especially the cationic formulations. Quantiosomes increased cytotoxicity against melanoma by 3?~?4-fold as compared to free carboplatin. In-vivo intratumoral administration demonstrated an increased drug depot in melanoma from 6 to 10 ng/mg by SPC-loaded and PEGylated quantiosomes relative to aqueous control. In-vivo fluorescence imaging showed that quantiosomes reduced leakage of QDs from melanoma. A fluorescence signal confined in tumors could be sustained for at least 24 h. Quantiosomes also exhibited a sensitive and prolonged fluorescence in ovarian tumors.

Conclusion

Niosomes containing QDs and carboplatin as a multifunctional nanosystems provide a non-expensive and efficient strategy to prolong drug retention and fluorescence signal in tumors.     

Thalamic glutamate decreases with cigarette smoking

Rationale

Findings from animal studies and human PET imaging indicate that nicotine and cigarette smoking affect glutamate (Glu) and related neurochemical markers in the brain and imply that smoking reduces extracellular Glu. As Glu release is mediated by nicotinic acetylcholine receptors (nAChRs), which are present at high concentrations in the thalamus, we examined the effects of smoking on thalamic Glu.

Objective

To determine the effects of tobacco smoking on thalamic glutamate levels.

Methods

Thalamic Glu levels were measured in vivo in 18 smokers and 16 nonsmokers using proton magnetic resonance spectroscopic imaging (¹H MRSI) at 1.5 T.

Results

Mean Glu levels did not differ significantly between the subject groups. However, within smokers, Glu levels were negatively correlated with self-reports of both cigarettes/day over the last 30 days (r?=??0.64, p?=?0.006) and pack-years of smoking (r?=??0.66, p?=?0.005).

Conclusions

Consistent with expectations based on preclinical studies, within smokers, cigarettes/day and pack-years are associated with reduced Glu in thalamus, a brain region rich in nAchRs. These results encourage work on candidate glutamatergic therapies for smoking cessation and suggest a noninvasive metric for their action in the brain.     

Synthesis and Evaluation of a Targeted Nanoglobular Dual-Modal Imaging Agent for MR Imaging and Image-Guided Surgery of Prostate Cancer

Purpose

To synthesize and evaluate a peptide targeted nanoglobular dual modal imaging agent specific to a cancer biomarker in tumor stroma for MRI and fluorescence visualization of prostate tumor in image-guided surgery.

Methods

A peptide (CGLIIQKNEC, CLT1) targeted generation 2 nanoglobular (polylysine dendrimer with a silsesquioxane core) dual modal imaging agent, CLT1-G2-(Gd-DOTA-MA)-Cy5, was synthesized by stepwise conjugation of Gd-DOTA-MA, Cy5 and peptide to the dendrimer. Contrast enhanced MR imaging of the targeted dual imaging agent was evaluated on a Bruker 7T animal scanner with male athymic nude mice bearing orthotopic PC3-GFP prostate tumor. Fluorescence tumor imaging of the agent was carried out on a Maestro fluorescence imaging system.

Results

The targeted agent CLT1-G2-(Gd-DOTA-MA)-Cy5 produced greater contrast enhancement in the tumor tissue than the control agent KAREC-G2-(Gd-DOTA-MA)-Cy5 at a dose of 30 μmol-Gd/kg in the MR images of the tumor bearing mice. Signal-to-noise ratio (SNR) of CLT1-G2-(Gd-DOTA-MA)-Cy5 in the tumor tissue was approximately 2 fold of that of the control agent in the first 15 min post-injection. The targeted agent also resulted in bright fluorescence signals in the tumor tissue.

Conclusion

The CLT1 peptide targeted nanoglobular dual-imaging agent CLT1-G2-(Gd-DOTA-MA)-Cy5 has a potential for MRI and fluorescence visualization of prostate tumor.     

Differential responses to anticipation of reward after an acute dose of the designer drugs benzylpiperazine (BZP) and trifluoromethylphenylpiperazine (TFMPP) alone and in combination using functional magnetic resonance imaging (fMRI)

Rationale

Functional magnetic resonance imaging (fMRI) studies have reported increased activation of the mesolimbic system in response to anticipation of rewarding stimuli. The anticipation of uncertain outcomes evokes activation in the amygdala, orbitofrontal cortex, inferior frontal gyrus and insula. Drugs known to effect dopaminergic and serotonergic neurons also alter regional activation.

Objectives

Benzylpiperazine (BZP) and/or trifluoromethylphenylpiperazine (TFMPP) have been recreationally used worldwide for more than a decade. BZP affects mainly dopaminergic neurons, while TFMPP has serotonergic effects.

Methods

We investigated the effects of an acute dose of BZP, TFMPP or a combination of BZP and TFMPP on the anticipation of reward in a double-blind, placebo-controlled, crossover study using fMRI. An event-related gambling paradigm was completed by healthy controls 90 min after taking an oral dose of either BZP (200 mg), TFMPP (either 50 or 60 mg), BZP + TFMPP (100?+?30 mg) or placebo.

Results

After giving BZP, the anticipation of a $4 reward decreased the activation of the inferior frontal gyrus, insula and occipital regions in comparison to placebo. TFMPP increased the activation of the putamen but decreased the activity in the insula relative to placebo. When BZP and TFMPP were given in combination, activation of the rolandic operculum occurred. The magnitude of reward also affected neural correlates.

Conclusion

We propose that the effects of BZP and TFMPP on dopaminergic and serotonergic circuitry, respectively, reflect regional changes. The dopaminergic effects of BZP appear to increase positive arousal and subsequently reduce the response to uncertainty, while TFMPP appears to alter the response to uncertainty by increasing emotional responses.