Mannan-Modified Solid Lipid Nanoparticles for Targeted Gene Delivery to Alveolar Macrophages

Purpose  

Cationic solid lipid nanoparticles (SLN) have established themselves during the past decades. They can efficiently bind DNA directly via ionic interaction and mediate gene transfection. One major problem with SLN is the lack of cell-targeting ability. In the present study, a mannan-based PE-grafted ligand was synthesized and used for the surface modification of DNA-loaded cationic SLN to prepare Man-SLN-DNA.     

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 -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°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.     

Delivery of siRNA into breast cancer cells via phage fusion protein-targeted liposomes

Efficacy of siRNAs as potential anticancer therapeutics can be increased by their targeted delivery into cancer cells via tumor-specific ligands. Phage display offers a unique approach to identify highly specific and selective ligands that can deliver nanocarriers to the site of disease. In this study, we proved a novel approach for intracellular delivery of siRNAs into breast cancer cells through their encapsulation into liposomes targeted to the tumor cells with preselected intact phage proteins. The targeted siRNA liposomes were obtained by a fusion of two parental liposomes containing spontaneously inserted siRNA and fusion phage proteins. The presence of pVIII coat protein fused to a MCF-7 cell-targeting peptide DMPGTVLP in the liposomes was confirmed by Western blotting. The novel phage-targeted siRNA-nanopharmaceuticals demonstrate significant down-regulation of PRDM14 gene expression and PRDM14 protein synthesis in the target MCF-7 cells. This approach offers the potential for development of new anticancer siRNA-based targeted nanomedicines. FROM THE CLINICAL EDITOR: In this study, the authors report a novel approach for targeted intracellular delivery of siRNAs into breast cancer cells through encapsulation into liposomes targeted to the tumor cells with preselected intact phage proteins.     

Pharmacoscintigraphic evaluation of polysorbate80-coated chitosan nanoparticles for brain targeting

Introduction

The blood-brain barrier (BBB) represents an insurmountable obstacle for delivery of a large number of drugs, including antibacterials, anticancer agents and neuropeptides. One approach to overcoming this barrier has been drug delivery to the brain using appropriately modified nanoparticles. Since polysorbate80 is known to facilitate uptake by brain endothelial cells, nanoparticles coated with polysorbate80 hold great promise for the transport of agents across the BBB. Since chitosan nanoparticles have extended circulation time in the blood and decreased uptake by the reticuloendothelial system, we decided to evaluate the efficiency of polysorbate80-coated chitosan nanoparticles as brain-delivery carriers.

Methods

Polysorbate80 (1% w/w)-coated, ultra-fine, crosslinked chitosan nanoparticles (10% crosslinking with glutaraldehyde) <100nm in diameter were prepared in the aqueous core of reverse micelles. After radiolabeling the nanoparticles with ^99mtechnetium (Tc), we studied their in vivo brain uptake profiles in Swiss Albino strain ‘A’ mice. The γ-scintigraphic technique was also employed to study the distribution of ^99mTc-labeled nanoparticles in the brain of New Zealand rabbits.

Results

Our studies revealed that the concentration of ^99mTc-labeled chitosan nanoparticles in the brain was increased nearly 5-fold when coated with polysorbate80 (1% w/w) compared with uncoated ^99mTc-labeled chitosan nanoparticles. The optimal composition of chitosan in polysorbate80 for the maximum delivery of nanoparticles to brain was found to be 1% w/w. Because of partial hydrophobicity rendered to the chitosan nanoparticles by coating with polysorbate80, blood kinetics data showed rapid clearance from blood of coated nanoparticles compared with uncoated nanoparticles. These results were further supported by the γ-scintigrams of New Zealand rabbits, which showed that ^99mTc-labeled chitosan nanoparticles coated with polysorbate80 (1% w/w) had a greater uptake by brain tissue than uncoated chitosan nanoparticles.

Conclusions

This study showed that chitosan nanoparticles coated with polysorbate80 have great potential as a drug delivery carrier to the brain. At a critical concentration of polysorbate80 (1% w/w) on the surface of chitosan nanoparticles, the translocation of nanoparticles from blood to brain was maximal.     

Formulation and cytotoxicity of doxorubicin nanoparticles carried by dry powder aerosol particles

Regional drug delivery via dry powder inhalers offers many advantages in the management of pharmaceutical compounds for the prevention and treatment of respiratory diseases. In the present study, doxorubicin (DOX)-loaded nanoparticles were incorporated as colloidal drug delivery system into inhalable carrier particles using a spray-freeze-drying technique. The cytotoxic effects of free DOX, carrier particles containing blank nanoparticles or DOX-loaded nanoparticles on H460 and A549 lung cancer cells were assessed using a colorimetric XTT cell viability assay. The mean geometric carrier particle size of 10+/-4 microm was determined using confocal laser scanning microscopy. DOX-loaded nanoparticles had a particle size of 173+/-43 nm after re-dissolving of the carrier particles. Compared to H460 cells, A549 cells showed less sensitivity to the treatment with free DOX. The DOX-nanoparticles showed in both cell lines a higher cytotoxicity at the highest tested concentration compared to the blank nanoparticles and the free DOX. The cell uptake of free DOX and DOX delivered by nanoparticles was confirmed using confocal laser scanning microscopy. This study supports the approach of lung cancer treatment using nanoparticles in dry powder aerosol form.     

Polymeric Nanoparticles Affect the Intracellular Delivery, Antiretroviral Activity and Cytotoxicity of the Microbicide Drug Candidate Dapivirine

Purpose

To assess the intracellular delivery, antiretroviral activity and cytotoxicity of poly(??-caprolactone) (PCL) nanoparticles containing the antiretroviral drug dapivirine.

Methods

Dapivirine-loaded nanoparticles with different surface properties were produced using three surface modifiers: poloxamer 338 NF (PEO), sodium lauryl sulfate (SLS) and cetyl trimethylammonium bromide (CTAB). The ability of nanoparticles to promote intracellular drug delivery was assessed in different cell types relevant for vaginal HIV transmission/microbicide development. Also, antiretroviral activity of nanoparticles was determined in different cell models, as well as their cytotoxicity.

Results

Dapivirine-loaded nanoparticles were readily taken up by different cells, with particular kinetics depending on the cell type and nanoparticles, resulting in enhanced intracellular drug delivery in phagocytic cells. Different nanoparticles showed similar or improved antiviral activity compared to free drug. There was a correlation between increased antiviral activity and increased intracellular drug delivery, particularly when cell models were submitted to a single initial short-course treatment. PEO-PCL and SLS-PCL nanoparticles consistently showed higher selectivity index values than free drug, contrasting with high cytotoxicity of CTAB-PCL.

Conclusions

These results provide evidence on the potential of PCL nanoparticles to affect in vitro toxicity and activity of dapivirine, depending on surface engineering. Thus, this formulation approach may be a promising strategy for the development of next generation microbicides.     

Budesonide Loaded PLGA Nanoparticles for Targeting the Inflamed Intestinal Mucosa—Pharmaceutical Characterization and Fluorescence Imaging

Purpose

The purpose of this study was to evaluate the specifically targeted efficiency of budesonide loaded PLGA nanoparticles for the treatment of inflammatory bowel disease (IBD).

Methods

The nanoparticles were prepared by an oil/water (O/W) emulsion evaporation technique. The nanoparticles were characterized for their size, shape and in vitro drug release profile. Solid state characterization was carried out by differential scanning calorimetry (DSC) and X-ray Power diffraction (XPRD). In order to evaluate the targeted efficiency of nanoparticles, a particle localization study in the healthy and in the inflamed colon was determined in vivo. These data were complemented by cryo-sections.

Results

Nanoparticles were 200?±?05 nm in size with a smooth and spherical shape. The encapsulation efficiency was around 85?±?3.5%, which was find-out by both, direct and indirect methods. Release of budesonide from the nanoparticles showed a biphasic release profile with an initial burst followed by sustained release. XPRD data revealed that the drug in the polymer matrix existed in crystalline state. Nanoparticles accumulation in inflamed tissues was evaluated by in-vivo imaging system and it was found that particles are accumulated in abundance at the site of inflammation when compared to the healthy group.

Conclusion

The study demonstrates that the budesonide loaded PLGA nanoparticles are an efficient delivery system for targeted drug delivery to the inflamed intestinal mucosa.

     

Novel Lansoprazole-Loaded Nanoparticles for the Treatment of Gastric Acid Secretion-Related Ulcers: In Vitro and In Vivo Pharmacokinetic Pharmacodynamic Evaluation

The objective of this study is to combine nanoparticle design and enteric coating technique to sustain the delivery of an acid-labile drug, lansoprazole (LPZ), in the treatment of acid reflux disorders. Lansoprazole-loaded Eudragit® RS100 nanoparticles (ERSNP-LPZ) as well as poly(lactic-co-glycolic acid) (PLGA) nanoparticles (PLGANP-LPZ) were prepared using a solvent evaporation/extraction method. The effects of nanoparticle charge and permeation enhancers on lansoprazole uptake was assessed in Caco-2 cells. The confocal microscopic images revealed the successful localization of nanoparticles in the cytoplasm of Caco-2 cells. The cellular uptake of positively charged Eudragit nanoparticles was significantly higher than that of negatively charged PLGA nanoparticles, which were enhanced by sodium caprate via the transcellular pathway. Both types of nanoparticles exhibited sustained drug release behavior in vitro. The oral administration of enteric-coated capsules filled with nanoparticles sustained and prolonged the LPZ concentration up to 24 h in ulcer-induced Wistar rats, and 92.4% and 89.2% of gastric ulcers healed after a 7-day treatment with either EC-ERSNP1010-Na caprate or EC-PLGANP1005-Na caprate, respectively.     

Chitosan-modified poly(D,L-lactide-co-glycolide) nanospheres for plasmid DNA delivery and HBV gene-silencing

Gene silencing using small interfering RNA (siRNA) has several potential therapeutic applications. In the present study, we investigated nanoparticles (NS) formulated using the biodegradable polymer, poly(D,L-lactide-co-glycolide) (PLGA) for plasmid DNA (pDNA) delivery. A cationic polymer, Chitosan (CHS), was incorporated in the PLGA matrix to improve pDNA loading efficiency and cellular uptake ability. PLGA-CHS NS were prepared by a spontaneous emulsion diffusion (SED) method, and various formulation factors were investigated. Spherical nanoparticles with particle size of around 60 nm were obtained under optimum formulation condition. The effectiveness of pDNA-loaded PLGA-CHS nanoparticles in expressing the indicative enhanced Green Fluorescent Protein (eGFP) and in slicing Hepatitis B virus (HBV) gene were examined in HepG2.2.15 cells. CHS-modified PLGA NS exhibited much higher loading efficiency than unmodified PLGA NS. CHS-PLGA NS showed a positive zeta potential, while plain-PLGA NS were negatively charged. EGFP expression studies by observation with confocal leaser scanning microscopy (CLSM) indicated that pDNA-loaded CHS-PLGA NS were more effectively taken up by the cells than plain-PLGA NS. The corresponding results showed that the HBV gene-silencing efficiency of CHS-PLGA NS was higher than those of plain-PLGA NS and naked pDNA. Thus, CHS-PLGA NS containing pDNA could provide an effective pDNA delivery system in vitro, showing that such an approach could be useful in the treatment of viral diseases in vivo.     

Quantifying Nanoparticle Internalization Using a High Throughput Internalization Assay

Purpose

The internalization of nanoparticles into cells is critical for effective nanoparticle mediated drug delivery. To investigate the kinetics and mechanism of internalization of nanoparticles into cells we have developed a DNA molecular sensor, termed the Specific Hybridization Internalization Probe - SHIP.

Methods

Self-assembling polymeric ‘pHlexi’ nanoparticles were functionalized with a Fluorescent Internalization Probe (FIP) and the interactions with two different cell lines (3T3 and CEM cells) were studied. The kinetics of internalization were quantified and chemical inhibitors that inhibited energy dependent endocytosis (sodium azide), dynamin dependent endocytosis (Dyngo-4a) and macropinocytosis (5-(N-ethyl-N-isopropyl) amiloride (EIPA)) were used to study the mechanism of internalization.

Results

Nanoparticle internalization kinetics were significantly faster in 3T3 cells than CEM cells. We have shown that ~90% of the nanoparticles associated with 3T3 cells were internalized, compared to only 20% of the nanoparticles associated with CEM cells. Nanoparticle uptake was via a dynamin-dependent pathway, and the nanoparticles were trafficked to lysosomal compartments once internalized.

Conclusion

SHIP is able to distinguish between nanoparticles that are associated on the outer cell membrane from nanoparticles that are internalized. This study demonstrates the assay can be used to probe the kinetics of nanoparticle internalization and the mechanisms by which the nanoparticles are taken up by cells. This information is fundamental for engineering more effective nanoparticle delivery systems. The SHIP assay is a simple and a high-throughput technique that could have wide application in therapeutic delivery research.

     

Development and characterization of a new plasmid delivery system based on chitosan-sodium deoxycholate nanoparticles

Chitosan is one of the most promising polymers for drug delivery through the mucosal routes because of its polycationic, biocompatible, and biodegradable nature, and particularly due to its mucoadhesive and permeation-enhancing properties. Bile salts are known to interact with lipid membranes, increasing their permeability. The addition of bile salts to chitosan matrices may improve the delivery characteristics of the system, making it suitable for mucosal administration of bioactive substances. In the present study we have developed chitosan nanoparticles using sodium deoxycholate as a counter ion and evaluated their potential as gene delivery carriers. Chitosan-sodium deoxycholate nanoparticles (CS/DS) obtained via a mild ionic gelation procedure using different weight ratios were used to encapsulate plasmid DNA (pDNA) expressing a "humanized" secreted Gaussia Luciferase as reporter gene (pGLuc, 5.7 kDa). Mean particle size, polydispersity index and zeta potential were evaluated in order to select the best formulation for further in vitro studies. The nanoparticles presented an average size of 153-403 nm and a positive zeta potential ranging from +33.0 to +56.9 mV, for nanoparticles produced with CS/DS ratios from 1:4 to 1:0.6 (w:w), respectively. The pDNA was efficiently encapsulated and AFM studies showed that pDNA-loaded nanoparticles presented a more irregular surface due to the interaction between cationic chitosan and negatively charged pDNA which results in a more compact structure when compared to empty nanoparticles. Transfection efficiency of CS/DS-pDNA nanoparticles into moderately (AGS) and well differentiated (N87) gastric adenocarcinoma cell lines was determined by measuring the expression of luciferase, while cell viability was assessed using the MTT reduction. The CS/DS nanoparticles containing encapsulated pDNA were able to transfect both AGS and N87 cell lines, being more effective with AGS cells, the less differentiated cell line. The highest enzymatic activity was achieved with 20% pDNA encapsulated and after 24 h of transfection time. Low cytotoxicity was observed for the CS/DS nanoparticles either with or without pDNA, suggesting this could be a new potential vehicle for mucosal delivery of pDNA.     

Highly specific HER2-mediated cellular uptake of antibody-modified nanoparticles in tumour cells

Nanoparticles represent useful drug delivery systems for the specific transport of drugs to tumour cells. In the present study biodegradable nanoparticles based on gelatin and human serum albumin (HSA) were developed. The surface of the nanoparticles was modified by covalent attachment of the biotin-binding protein NeutrAvidin enabling the binding of biotinylated drug targeting ligands by avidin-biotin-complex formation. Using the HER2 receptor specific antibody trastuzumab (Herceptin) conjugated to the surface of these nanoparticles, a specific targeting to HER2-overexpressing cells could be shown. Attachment of the antibody-conjugated nanoparticles to the surface of HER2-overexpressing cells was time and dose dependent. Confocal laser scanning microscopy demonstrated an effective internalisation of the nanoparticles by HER2-overexpressing cells via receptor-mediated endocytosis. The results indicate that nanoparticles conjugated with an antibody against a specific tumour antigen holds promise, as selective drug delivery systems for the treatment of tumours expressing a specific tumour antigen. To our knowledge, this is the first study that demonstrates the effective and specific targeting of protein-based nanoparticles as drug delivery systems.     

Convection-enhanced delivery and in vivo imaging of polymeric nanoparticles for the treatment of malignant glioma

A major obstacle to the management of malignant glioma is the inability to effectively deliver therapeutic agent to the tumor. In this study, we describe a polymeric nanoparticle vector that not only delivers viable therapeutic, but can also be tracked in vivo using MRI. Nanoparticles, produced by a non-emulsion technique, were fabricated to carry iron oxide within the shell and the chemotherapeutic agent, temozolomide (TMZ), as the payload. Nanoparticle properties were characterized and subsequently their endocytosis-mediated uptake by glioma cells was demonstrated. Convection-enhanced delivery (CED) can disperse nanoparticles through the rodent brain and their distribution is accurately visualized by MRI. Infusion of nanoparticles does not result in observable animal toxicity relative to control. CED of TMZ-bearing nanoparticles prolongs the survival of animals with intracranial xenografts compared to control. In conclusion, the described nanoparticle vector represents a unique multifunctional platform that can be used for image-guided treatment of malignant glioma.From the Clinical EditorGBM remains one of the most notoriously treatment-unresponsive cancer types. In this study, a multifunctional nanoparticle-based temozolomide delivery system was demonstrated to possess enhanced treatment efficacy in a rodent xenograft GBM model, with the added benefit of MRI-based tracking via the incorporation of iron oxide as a T2* contrast material in the nanoparticles.     

Ocular drug delivery of progesterone using nanoparticles

The objective of this study was to evaluate ocular delivery of a lipid-soluble drug, [3H]progesterone, using nanoparticles. Polybutylcyanoacrylate nanoparticles loaded with [3H]progesterone were prepared by an emulsion polymerization technique using a hydrophilic continuous phase. The resulting nanoparticle suspension contained 2 x 10(-5) M progesterone. It was found that, at equilibrium, 99 per cent of the progesterone resided in the nanoparticles and the remainder in the aqueous phase indicating an excellent encapsulation efficiency. In addition, an appropriate control solution of progesterone was prepared, which did not contain polybutylcyanoacrylate. Concentrations of [3H]progesterone in various ocular tissues of the albino rabbit were monitored at various times following topical administration of either the nanoparticle suspension or the control solutions. Comparison of the concentration-time profiles indicates that tissue concentration of progesterone following topical administration of nanoparticles is generally four to five times less than that obtained with control solutions. This decreased concentration suggests that, due to the high affinity of progesterone for the nanoparticles, the drug is being made less available for absorption during its residence time in the precorneal area. The utility of nanoparticles as an ocular drug delivery system may depend on optimizing lipophilic-hydrophilic properties of the polymer-drug system, in addition to increasing retention efficiency in the precorneal pocket.     

l-Cysteine conjugated poly l-lactide nanoparticles containing 5-fluorouracil: formulation,characterization, release and uptake by tissues in vivo

Abstract

Context: Targeted delivery of drugs is still a therapeutic challenge and numerous methods have been reported for the same.

Objective: In this study, emphasis was placed on developing nanoparticles loaded with 5-fluorouracil (FU) and modifying the surface of the nanoparticles by conjugation with amino acid, to improve the distribution of 5-FU in the lungs.

Methods: An emulsion solvent evaporation technique was used to formulate nanoparticles of FU using Poly l-lactide and Pluronic F-68. The nanoparticles were conjugated with l-Cysteine using EDC as the activator of COOH group and were evaluated for product yield, particle size, surface morphology, amount of conjugation by Ellman’s method and in vitro drug release study.

Results and conclusion: The results indicated 60–65% yield with an average particle size of 242.7?±?37.11?nm for the cysteine conjugated nanoparticle (CNP) formulation and more than 70% conjugation of cysteine. The cumulative percentage of drug released over a period of 24?h was found to be 58%. An increase in distribution of the delivery system in lungs (11.4% ID after 1?h) in mice was found indicating the role of l-Cysteine in the transport mechanism to the lungs. In vivo kinetic studies in rats revealed higher circulation time of CNP as compared to pure FU solution. The study helps in designing a colloidal delivery system for increased distribution of drugs to the lungs and may be helpful in delivery of drugs in conditions like non-small cell lung carcinomas.     

Preparation and evaluation of thiomer nanoparticles via high pressure homogenization

The aim of this study was to establish and evaluate a high pressure homogenization method for the preparation of thiomer nanoparticles. Particles were formulated by incorporation of the model protein horseradish peroxidase in chitosan-glutathione (Ch-GSH) and poly(acrylic acid)-glutathione (PAA-GSH) via co-precipitation followed by air jet milling. The resulting microparticles were suspended in distilled water using an Ultraturax and subsequently micronized by high pressure homogenization. Finally, resulting particles were evaluated regarding size distribution, shape, zeta potential, drug load, protein activity and release behaviour. The mean particle size after 30 cycles with a pressure of 1500 bar was 538 ± 94 nm for particles consisting of Ch-GSH and 638 ± 94 nm for particles consisting of PAA-GSH. Nanoparticles of Ch-GSH had a positive zeta-potential of +1.03 mv, whereas nanoparticles from PAA-GSH had a negative zeta potential of ?6.21 mv. The maximum protein load for nanoparticles based on Ch-GSH and based on PAA-GSH was 45 ± 2% and 37 ± %, respectively. The release profile of nanoparticles followed a first order release kinetic. Thiolated nanoparticles prepared by a high pressure homogenization technique were shown to be stable and provide controlled drug release characteristics. The preparation method described here might be a useful tool for a more upscaled production of nanoparticulate drug delivery systems.     

Prestin binding peptides as ligands for targeted polymersome mediated drug delivery to outer hair cells in the inner ear

Targeted delivery of treatment agents to the inner ear using nanoparticles is an advanced therapeutic approach to cure or alleviate hearing loss. Designed to target the outer hair cells of the cochlea, two 12-mer peptides (A(665) and A(666)) with affinity to prestin were identified following 3 rounds of sequential phage display. Two-round display with immobilized prestin protein was used to enrich the library for full-length prestin. The last round was performed using Cos-7 cells transiently transfected with a cCFP-prestin plasmid to display phages expressing peptides restrictive to the extracellular loops of prestin. The binding properties of A(665) and A(666) shown by flow cytometry demonstrated selectivity to prestin-expressing Chinese hamster ovary cells. PEG6K-b-PCL19K polymersomes covalently labelled with these peptides demonstrated effective targeting to outer hair cells in a rat cochlear explant study.     

Highly Specific HER2-mediated Cellular Uptake of Antibody-modified Nanoparticles in Tumour Cells

Nanoparticles represent useful drug delivery systems for the specific transport of drugs to tumour cells. In the present study biodegradable nanoparticles based on gelatin and human serum albumin (HSA) were developed. The surface of the nanoparticles was modified by covalent attachment of the biotin–binding protein NeutrAvidin? enabling the binding of biotinylated drug targeting ligands by avidin–biotin-complex formation. Using the HER2 receptor specific antibody trastuzumab (Herceptin®) conjugated to the surface of these nanoparticles, a specific targeting to HER2-overexpressing cells could be shown. Attachment of the antibody-conjugated nanoparticles to the surface of HER2-overexpressing cells was time and dose dependent. Confocal laser scanning microscopy demonstrated an effective internalisation of the nanoparticles by HER2-overexpressing cells via receptor-mediated endocytosis. The results indicate that nanoparticles conjugated with an antibody against a specific tumour antigen holds promise, as selective drug delivery systems for the treatment of tumours expressing a specific tumour antigen. To our knowledge, this is the first study that demonstrates the effective and specific targeting of protein-based nanoparticles as drug delivery systems.     

Chitosan/cyclodextrin nanoparticles as macromolecular drug delivery system

The aim of this study was to generate a new type of nanoparticles made of chitosan (CS) and carboxymethyl-β-cyclodextrin (CM-β-CD) and to evaluate their potential for the association and delivery of macromolecular drugs. CS and CM-β-CD or mixtures of CM-β-CD/tripolyphosphate (TPP) were processed to nanoparticles via the ionotropic gelation technique. The resulting nanoparticles were in the size range of 231–383 nm and showed a positive zeta potential ranging from +20.6 to +39.7 mV. These nanoparticles were stable in simulated intestinal fluid pH 6.8 at 37 °C for at least 4 h. Elemental analysis studies revealed the actual integration of CM-β-CD to CS nanoparticles. Insulin and heparin used as macromolecular model drugs, could be incorporated into the different nanocarriers with association efficiencies of 85.5–93.3 and 69.3–70.6%, respectively. The association of these compounds led to an increase of the size of the nanoparticles (366–613 nm), with no significant modification of their zeta potentials (+23.3 to +37.1 mV). The release profiles of the associated macromolecules were highly dependent on the type of molecule and its interaction with the nanomatrix: insulin was very fast released (84–97% insulin within 15 min) whereas heparin remained highly associated to the nanoparticles for several hours (8.3–9.1% heparin within 8 h). In summary, CS-CD (cyclodextrin) nanoparticles may be considered as nanocarriers for the fast or slow delivery of macromolecules.     

PLGA-PEI nanoparticles for gene delivery to pulmonary epithelium.

Pulmonary gene delivery is thought to play an important role in treating genetically related diseases and may induce immunity towards pathogens entering the body via the airways. In this study we prepared poly (D,L-lactide-co-glycolide) (PLGA) nanoparticles bearing polyethyleneimine (PEI) on their surface and characterized them for their potential in serving as non-viral gene carriers to the pulmonary epithelium. Particles that were synthesized at different PLGA-PEI ratios and loaded with DNA in several PEI-DNA ratios, exhibited narrow size distribution in all formulations, with mean particle sizes ranging between 207 and 231 nm. Zeta potential was strongly positive (above 30 mV) for all the PEI-DNA ratios examined and the loading efficiency exceeded 99% for all formulations. Internalization of the DNA-loaded PLGA-PEI nanoparticles was studied in the human airway submucosal epithelial cell line, Calu-3, and DNA was detected in the endo-lysosomal compartment 6 h after particles were applied. Cytotoxicity of these nanoparticles was dependent on the PEI-DNA ratio and best cell viability was achieved by PEI-DNA ratios 1:1 and 0.5:1. These findings demonstrate that PLGA-PEI nanoparticles are a potential new delivery system to carry genes to the lung epithelium.