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At least 253 records · Page 14Linked to original sources
PubMed2005

Metalloproteinase and cytokine production by THP-1 macrophages following exposure to chitosan-DNA nanoparticles.

The use of nanoparticles for gene therapy is gaining more and more interest for medical applications. Chitosan is among the candidate polymers that have a potential application as a gene delivery system. Before using chitosan-DNA nanoparticles in vivo, one must study their interaction and cell's behavior. Since macrophages play an important role in inflammatory processes, this study was performed to investigate the effects of chitosan-DNA nanoparticles on human THP-1 cell line. Cytokine (TNF-alpha, IL-1beta, IL-6 and IL-10) and metalloproteinase (MMP-2 and MMP-9) release as well as their inhibitors (TIMP-1 and TIMP-2) were assessed after time course incubation with different amount of nanoparticles. Their secretion was quantified by enzyme-linked immunosorbent assay. Gelatinolytic activity of MMP-2 and MMP-9 was determined by zymography in cell supernatants and lysates. Cytokine secretion was not detected even in the presence of high amount of nanoparticles. On the contrary, the secretion of MMP-9 in cell supernatants increased significantly after 24 and 48 h in comparison with non-treated cells. MMP-2 secretion was augmented only after 48 h for the highest concentrations of nanoparticles (10 and 20 microg/ml DNA content). However, zymography studies showed that the secreted MMPs were in the proactive forms, while the active form of MMP-9, but not MMP-2, was detected in cell lysates when 10 and 20 microg/ml DNA containing nanoparticles were used. In conclusion, exposure of THP-1 macrophages to Ch-DNA nanoparticles did not induce release of proinflammatory cytokines. The presence of active MMP-9 within the macrophages could possibly be related to nanoparticle phagocytosis and degradation rather than to inflammatory reactions.

Cell Line↗
PubMed2005

Preparation and characterisation of antibody modified gelatin nanoparticles as drug carrier system for uptake in lymphocytes.

Established methods of protein chemistry can be used for the effective attachment of drug targeting ligands to the surface of protein-based nanoparticles. In the present work gelatin nanoparticles were used for the attachment of biotinylated anti-CD3 antibodies by avidin-biotin-complex formation. These antibody modified nanoparticles represent a promising carrier system for the specific drug targeting to T-lymphocytes. The objective of this work was the comprehensive quantification of every chemical reaction step during the preparation procedure of these cell specific nanoparticles. Gelatin nanoparticles were formed by a two-step desolvation process. After the first desolvation step the remaining sediment and the supernatant were analysed for molecular weight distribution by size exclusion chromatography (SEC). Nanoparticles then were formed using the high molecular gelatin fraction and subsequently were stabilised by glutaraldehyde crosslinking. A part of the detectable amino groups on the particle surface was reacted with 2-iminothiolane in order to introduce reactive sulfhydryl groups. The thiolated nanoparticles were coupled to NeutrAvidin (NAv) which previously was activated with the heterobifunctional crosslinker sulfo-MBS. All these reaction steps were quantified by photometry or gravimetry. The functionality of NAv after covalent conjugation was confirmed by a biotin-4-fluorescein assay. The NAv-modified nanoparticles then were used for the binding of biotinylated anti-CD3 antibodies by avidin-biotin-complex formation. A highly effective attachment of the ligand was ascertained by different, indirect methods: immunoblotting and fluorimetry. Therefore, a well-defined nanoparticle system with drug targeting ligand modification was established that holds promise for further effective preclinical testing.

Antibodies↗
PubMed2005

New surface-modified lipid nanoparticles as delivery vehicles for salmon calcitonin.

The aim of the present work was to develop a new nanoparticulate system, consisting of lipid nanoparticles coated with chitosan (CS), intended for the oral administration of peptide drugs. These new nanoparticles were studied, and compared with the previously developed PEG-coated lipid nanoparticles, with regard to their ability to incorporate and deliver the model peptide salmon calcitonin (sCT). Moreover, the influence of the core composition, either a solid triglyceride (tripalmitin), or a mixture of a liquid and a solid triglyceride (Miglyol 812 and tripalmitin) on the encapsulation and release of sCT was investigated. The results showed that a CS coating could be formed around the tripalmitin nanoparticles by simple incubation of the lipid cores in a CS solution, due to the high affinity of CS for the lipid core. In addition, sCT could be efficiently associated, irrespective of the core composition, to the nanoparticles. This important association was attributed to the marked affinity of sCT for the lipid cores, as confirmed by the adsorption studies. However, the nature of the coating affected the surface association of the peptide, which was less important for the nanoparticles coated with CS, than for PEG-coated nanoparticles. This was attributed to the displacement of the sCT molecules located on the surface of the nanoparticles by the positively charged CS molecules. This reduced surface association led to a decrease in the burst release effect, which was more pronounced for the nanoparticles coated with PEG than for those coated with CS. Following the initial burst, the systems provided a continuous and slow release of the associated peptide, independently of the nature of the coating. This slow release was attributed to the affinity of the peptide for the lipids and to the absence of degradation of the lipid matrix under the in vitro release conditions.

Animals↗
PubMed2005

Nanoparticle formulation may affect the stabilization of an antiischemic prodrug.

The prodrug 5'-octanoyl-CPA (Oct-CPA) of the antiischemic N6-cyclopentyladenosine (CPA) has been encapsulated by nanoprecipitation in poly(lactic acid) nanoparticles, which have been recovered by gel-filtration, ultra-centrifugation or dialysis. We have analysed how different surfactants and purification methods can influence the nanoparticle characteristics. The particle sizes have been obtained by scanning electron microscope, whereas a SdFFF system was employed to detect their distributions. The Oct-CPA release from nanoparticles and stabilities in human blood of free and encapsulated prodrug have been analysed by HPLC techniques. The effects of nanoparticles on CPA interaction toward adenosine A1 receptor (its action site) have been analysed using radiolabelled drugs. The smallest nanoparticles and the best degree of homogeneity have been obtained using sodium cholate; the best recovery has been achieved by dialysis, whereas gel-filtration and ultra-centrifugation have induced the greatest removal of surfactants. The release of Oct-CPA was better controlled from the nanoparticles obtained using Pluronic F68 and purified by gel-filtration or ultra-centrifugation. Similarly, these nanoparticles better increased the stability of the prodrug in human blood. In particular, the nanoparticles purified by ultra-centrifugation induced a strong stability to a fraction of the encapsulated Oct-CPA. Any interference by unloaded nanoparticles has been registered for CPA-adenosine A1 receptor interaction.

Adenosine↗
PubMed2005

Surface modification of monodisperse magnetite nanoparticles for improved intracellular uptake to breast cancer cells.

Nanoparticles have been widely used for a variety of biomedical applications and there is a growing need for highly specific and efficient uptake of the nanoparticles into target cells. Poly(ethylene glycol) (PEG), folic acid (FA), and their conjugate PEG-FA were attached to magnetite nanoparticles to compare their effects on the improvement of intracellular uptake of the nanoparticles to human breast cancer cells, BT-20. AFM and TEM results indicated that the nanoparticles after surface modification were monodisperse, with coatings on individual nanoparticles. The cell culture experiments showed that the PEG-FA coated nanoparticles were internalized into BT-20 cancer cells and exhibited higher efficiency of intracellular uptake than only PEG- or FA-coated nanoparticles. The surface modification protocols can also be used to modify the surfaces of other nanoparticles for targeting intracellular delivery.

Breast Neoplasms↗
PubMed2006

Synthesis and characterization of photoluminescent In-doped CdSe nanoparticles.

Indium-doped CdSe nanoparticles have been synthesized and characterized. Their light absorption, photoluminescence, and structure are similar to undoped CdSe nanoparticles. The greater part of the In associated with the nanoparticles is removed when the nanoparticles undergo ligand exchange by pyridine. As observed with undoped nanoparticles, a ZnS capping layer on the indium-doped nanoparticles results in enhanced nanocrystal photoluminescence. Also, the ZnS cap enhances the retention of In by the nanoparticles. Elemental analysis shows ligand exchange causes CdSe to be lost and capping with ZnS results in the loss of Se. We conclude that In-doped nanoparticles have most of the In on their surface, capping helps the nanoparticles retain the In, and they do not have altered electronic properties.

Journal Article↗
PubMed2006

Probing colloidal forces between a Si3N4 AFM tip and single nanoparticles of silica and alumina.

The atomic force microscope (AFM) has been used to measure surface forces between silicon nitride AFM tips and individual nanoparticles deposited on substrates in 10(-4) and 10(-2) M KCl solutions. Silica nanoparticles (10 nm diameter) were deposited on an alumina substrate and alumina particles (5 to 80 nm diameter) were deposited on a mica substrate using aqueous suspensions. Ionic concentrations and pH were used to manage attractive substrate-particle electrostatic forces. The AFM tip was located on deposited nanoparticles using an operator controlled offset to achieve stepwise tip movements. Nanoparticles were found to have a negligible effect on long-range tip-substrate interactions, however, the forces between the tip and nanoparticle were detectable at small separations. Exponentially increasing short-range repulsive forces, attributed to the hydration forces, were observed for silica nanoparticles. The effective range of hydration forces was found to be 2-3 nm with the decay length of 0.8-1.3 nm. These parameters are in a good agreement with the results reported for macroscopic surfaces of silica obtained using the surface force apparatus suggesting that hydration forces for the silica nanoparticles are similar to those for flat silica surfaces. Hydration forces were not observed for either alumina substrates or alumina nanoparticles in both 10(-4) M KCl solution at pH 6.5 and 10(-2) M KCl at pH 10.2. Instead, strong attractive forces between the silicon nitride tip and the alumina (nanoparticles and substrate) were observed.

Journal Article↗
PubMed2004

Effect of cellular uptake of gelatin nanoparticles on adhesion, morphology and cytoskeleton organisation of human fibroblasts.

The aim of present study was to prepare nanometer sized particles of gelatin via water-in-oil microemulsion system for drug and gene delivery applications. In this study, cross-linked gelatin nanoparticles encapsulating a fluorescent marker molecule fluorescein isothiocyanate-dextran (FITC-Dex, Mol. Wt. 19.3kDa) have been prepared, characterized and their influence on human fibroblasts has been assessed in terms of cell adhesion, cytotoxicity, light microscopy, scanning electron microscopy (SEM), transmission electron microscopy (TEM) and observation of cytoskeleton organisation. Gelatin nanoparticles were prepared inside the aqueous cores of sodium bis(2-ethylhexyl) sulfosuccinate (AOT)/n-hexane reverse micelles. Transmission electron microscopy image showed that the particles are spherical in shape with size of 37+/-0.84 nm diameter. The release of FITC-Dex from the nanoparticles in phosphate buffer saline (pH 7.4) is found to increase with time and about 80% of the encapsulated dye is released in 6 h. Cell adhesion studies with human fibroblasts have shown that gelatin nanoparticles do not affect the number of cells adhered to glass as compared to control cells with no particles. Standard cell viability assay demonstrated that cells incubated with gelatin nanoparticles remained more than 100% viable at concentration as high as 500 microg/ml. From SEM image, it was observed that the nanoparticles were internalised and the fibroblasts exhibited vacuoles in the cell body with cell membrane abnormalities. Endocytosis of nanoparticles was confirmed from TEM studies and it resulted in disruption of F-actin and beta-tubulin cytoskeleton. These studies show that the gelatin nanoparticles prepared by water-in-oil microemulsion systems are endocytosed by the fibroblasts without being toxic to cells even at high concentration of nanoparticles.

Actins↗
PubMed2004

Hydrogel pullulan nanoparticles encapsulating pBUDLacZ plasmid as an efficient gene delivery carrier.

This study provides a method for enhancing the delivery of nucleic acid molecules to cells by encapsulating it inside the hydrogel pullulan nanoparticles. In this study, pullulan nanoparticles encapsulating pBUDLacZ plasmid has been prepared inside the aqueous droplets of w/o microemulsions. Transmission electron microscopy (TEM) image showed that the particles are spherical in shape with size of 45+/-0.80 nm diameter. Cell cytotoxicity studies as determined by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl-tetrazolium bromide (MTT) assay demonstrated that cells incubated with nanoparticles remained more than 100% viable at nanoparticle concentration as high as 1000 microg/ml. From scanning electron microscope images, it was observed that the nanoparticles were internalised and the cells exhibited vacuoles in the cell body due to nanoparticle internalisation. Endocytosis of nanoparticles resulted in disruption of F-actin and beta-tubulin cytoskeleton of human fibroblasts. The efficacy of transfection in vitro on HEK293 and COS-7 cells demonstrated cell type dependence, with COS cells having a higher gene expression. The beta-gal expression in COS-7 cells by pullulan nanoparticle was comparable to commercially available Lipofectamine 2000. The results of this study are encouraging for the development of pullulan nanoparticles as an intracellular delivery system for drugs and genes.

Animals↗
PubMed2005

In vitro and in vivo activities of verteporfin-loaded nanoparticles.

The main goal of this study was to develop a dispersed polymeric drug delivery system for verteporfin, suitable for intravenous administration and capable of improving its phototherapeutic index and minimizing the side effects. To achieve this objective, two types of verteporfin-loaded nanoparticles (167 and 370 nm in diameter) based on poly(D,L-lactide-co-glycolide) were prepared using the salting-out technique and were first tested on EMT-6 mammary tumor cells in comparison with an aqueous solution (DMSO/PBS). It was observed that small nanoparticles exhibited greater photocytotoxicity compared to large nanoparticles or DMSO/PBS, and the photocytotoxic efficiency was graded as small nanoparticles>DMSO/PBS>large nanoparticles. Furthermore, verteporfin, entrapped into small nanoparticles transferred to serum proteins more rapidly than when dissolved in DMSO/PBS. Drug clearance, measured by skin phototoxicity investigated in mice exposed to simulated sunlight 15 to 150 min after the injection of small nanoparticles was modest at early light exposure times with the small nanoparticles and diminished rapidly with later exposure times. Tumor bioassay results indicated that verteporfin incorporated into small nanoparticles effectively controlled tumor growth for 20 days in mice with early light irradiation times following drug administration.

Animals↗
PubMed2005

Role of zinc in formulation of PLGA/PLA nanoparticles encapsulating betamethasone phosphate and its release profile.

The purpose of this study was to develop poly(D,L-lactic/glycolic acid) (PLGA) or poly(D,L-lactic acid) (PLA) nanoparticles of less than 200 nm in diameter that encapsulated water-soluble corticosteroid derivatives for sustained release and targeting to inflammatory sites. Nanoparticles were prepared with PLGA (or PLA), zinc, betamethasone phosphate and surfactant by an oil-in-water solvent diffusion method. With this method, the efficiency of encapsulating betamethasone phosphate in the nanoparticles and the particle size were significantly affected by various factors, such as the concentration of PLGA (or PLA) and the amount of zinc added. Nanoparticles ranging from 80 to 250 nm in diameter could be prepared, with a maximum betamethasone phosphate content of 8% (w/w). Betamethasone phosphate was gradually released from the nanoparticles in diluted serum, and the release rate depended on the glycolic/lactic acid ratio and on the molecular weight of PLGA or PLA. Betamethasone was gradually released over at least 8 days from murine macrophages that had internalized betamethasone phosphate-encapsulated nanoparticles in vitro, and the rate of release was slower than from nanoparticles prepared without zinc. These results suggest that zinc increases the efficiency of encapsulating betamethasone phosphate in nanoparticles and also promotes sustained release of betamethasone phosphate from the nanoparticles.

Animals↗
PubMed2001

Preparation and characterisation of rose Bengal-loaded surface-modified albumin nanoparticles.

Surface-modified albumin nanoparticles were prepared from two poly(ethylene glycol)-human serum albumin conjugates: poly(thioetheramido acid)-poly(ethylene glycol) copolymer-grafted HSA (HSA-PTAAC-PEG) and methoxy poly(ethylene glycol)-grafted HSA (HSA-mPEG). Rose bengal (RB) was used as a model drug for encapsulation into the nanoparticles either during the particle production or by adsorption post particle preparation. The drug incorporation and release was affected by the different production methods and the different polymer compositions. When RB was loaded in HSA and HSA/HSA-PTAAC-PEG nanoparticles, up to 5% (w/w) drug content was achieved. The drug loading in HSA-mPEG nanoparticles was much lower and the results from the microcalorimetry study indicated that the low loading efficiency was due to less drug-protein binding sites available in the HSA-mPEG molecule as compared to the HSA molecule. The release of RB from the albumin nanoparticles was very slow in PBS and dramatically accelerated in the presence of trypsin. Compared with unmodified nanoparticles, the slower release of RB from the surface-modified HSA nanoparticles in the presence of the enzyme suggested that the existence of a steric hydrophilic barrier on the surface of the nanoparticles made digestion of the nanoparticles more difficult.

Administration, Oral↗
PubMed2002

Behavior of mucoadhesive nanoparticles having hydrophilic polymeric chains in the intestine.

The behavior of nanoparticles having surface hydrophilic poly(N-isopropylacrylamide), poly(N-vinylacetamide), poly(vinylamine) or poly(methacrylic acid) chains in the intestine was examined. The permeability of salmon calcitonin (sCT) from the mucosal to serosal side of the everted jejunum was enhanced in the presence of nanoparticles. This enhancement, which correlated with the amount of sCT incorporated in nanoparticles, disappeared completely after removal of the mucous layer. When fluorescein isothiocyanate-dextran (FD-4) was used instead of sCT, its permeability through the everted jejunum with and without mucous layer was not enhanced by any nanoparticles, because FD-4 was not incorporated in nanoparticles at all. These findings indicated that the accumulation of nanoparticles incorporating sCT in the mucous layer resulted in the enhancement of sCT permeability. Nanoparticles with poly(N-isopropylacrylamide) or poly(vinylamine) on their surfaces did not cause any damage to the intestinal mucosa. Also, none of the nanoparticles opened the tight junction of the intestinal membrane. It was concluded that mucoadhesion of nanoparticles incorporating sCT to the gastrointestinal mucosa contributed to the absorption enhancement of sCT.

Alkaline Phosphatase↗
PubMed1998

Poly(vinyl alcohol) nanoparticles prepared by freezing-thawing process for protein/peptide drug delivery.

Poly(vinyl alcohol) (PVA) hydrogel nanoparticles have been prepared by using a water-in-oil emulsion technology plus cyclic freezing-thawing process. The PVA hydrogel nanoparticles prepared by this method are suitable for protein/peptide drug delivery since formation of the hydrogel does not require crosslinking agents or other adjuvants and does not involve any residual monomer. Particularly, there is no emulsifier involved in this new method. Bovine serum albumin (BSA), as a model protein drug, is incorporated into the PVA hydrogel nanoparticles. The PVA hydrogel nanoparticles possess a skewed or log-normal size distribution. The average diameter of the PVA hydrogel nanoparticles is 675.5+/-42.7 nm. Protein drug loading efficiency in the PVA hydrogel nanoparticles is 96.2+/-3.8%. The PVA hydrogel nanoparticles swell in an aqueous solution and the swelling degree increases with the increase of temperature. In vitro release studies show that the BSA release from the nanoparticles can be prolonged to 30 h. The BSA release follows a diffusion-controlled mechanism. The number of freezing-thawing cycle and release temperature both influence BSA release rate considerably. Less freezing-thawing cycle or higher release temperature leads to faster drug release. The BSA is stable during preparation of the PVA hydrogel nanoparticles.

Chemical Phenomena↗
PubMed1999

PLGA nanoparticles prepared by nanoprecipitation: drug loading and release studies of a water soluble drug.

The nanoprecipitation technique for preparation of nanoparticles suffers the drawback of poor incorporation of water soluble drugs. The aim of this study was therefore to assess various formulation parameters to enhance the incorporation of a water soluble drug (procaine hydrochloride) into poly(dl-lactide-co-glycolide) (PLGA) nanoparticles prepared by this technique. Approaches investigated for drug incorporation efficiency enhancement included the influence of aqueous phase pH, replacement of procaine hydrochloride with procaine dihydrate and the inclusion of excipients: poly(dl-lactide) (PLA) oligomers, poly(methyl methacrylate-co-methacrylic acid) (PMMA-MA) or fatty acids into the formulation. The nanoparticles produced were submicron size (<210 nm) and of low polydispersity. It was found that an aqueous phase pH of 9.3, replacement of procaine hydrochloride with procaine dihydrate and the incorporation of PMMA-MA, lauric and caprylic acid into the formulation could enhance drug incorporation efficiency without the size, morphology and nanoparticle recovery being adversely influenced. For instance changing the aqueous phase pH from 5.8 to 9.3 increased nanoparticle recovery from 65.1 to 93.4%, drug content from 0.3 to 1.3% w/w and drug entrapment from 11.0 to 58.2%. However, the presence of high ratios of lauric acid and procaine dihydrate in the formulation adversely affected the morphology and size of the nanoparticles. Also, PLA oligomers were not considered a feasible approach since it decreased drug entrapment from 11.0 to 8.4% and nanoparticle recovery from 65.1 to 19.6%. Drug release from nanoparticles appears to consist of two components with an initial rapid release followed by a slower exponential stage. This study has demonstrated that formulation variables can be exploited in order to enhance the incorporation of a water soluble drug into PLGA nanoparticles by the nanoprecipitation technique.

Buffers↗
PubMed2002

Biodegradable poly(epsilon -caprolactone) nanoparticles for tumor-targeted delivery of tamoxifen.

To increase the local concentration of tamoxifen in estrogen receptor (ER) positive breast cancer, we have developed and characterized nanoparticle formulation using poly(epsilon -caprolactone) (PCL). The nanoparticles were prepared by solvent displacement method using acetone-water system. Particle size analysis, scanning electron microscopy, zeta potential measurements, and differential scanning calorimetry (DSC) were used for nanoparticle characterization. Biodegradation studies were performed in the presence and absence of Pseudomonas lipase in phosphate-buffered saline (PBS, pH 7.4) at 37 degrees C. Tamoxifen loading over different concentrations was analyzed by high-performance liquid chromatography (HPLC) and the optimum loading concentration was determined. In vitro release studies were performed in 0.5% (w/v) sodium lauryl sulfate (SLS) containing PBS at 37 degrees C. Cellular uptake and distribution of fluorescent-labeled nanoparticles was examined in MCF-7 breast cancer cells. SEM micrographs and Coulter analysis showed nanoparticles with spherical shape and uniform size distribution (250-300 nm), respectively. Zeta potential analysis revealed a positive surface charge of +25 mV on the tamoxifen-loaded formulation. Being hydrophobic crystalline polyester, PCL did not degrade in PBS alone, but the degradation was enhanced by the presence of lipase. The maximum tamoxifen loading efficiency was 64%. Initial burst release of tamoxifen was observed, probably due to significant surface presence of the drug on the nanoparticles. A large fraction of the administered nanoparticle dose was taken up by MCF-7 cells through non-specific endocytosis. The nanoparticles were found in the perinuclear region after 1 h. Results of the study suggest that nanoparticle formulations of selective ER modulators, like tamoxifen, would provide increased therapeutic benefit by delivering the drug in the vicinity of the ER.

Absorbable Implants↗
PubMed2003

Ultrasonication of chitosan and chitosan nanoparticles.

The objective of this study was to evaluate the effects of ultrasonication on chitosan molecules and nanoparticles. Molecular weight (M(v)) of chitosan HCl (M(v) 146 kDa and degree of deacetylation (DD) 96%) decreased linearly with increasing duration and amplitude of ultrasonication. DD and FTIR absorption were unaffected. X-ray diffraction (XRD) analysis suggested greater chain alignment in the ultrasonicated chitosan samples. Chitosan nanoparticles had mean diameter of 382 nm, polydispersity of 0.53 and zeta potential of 47 mV. Ultrasonication administered at increasing duration or amplitude decreased the mean diameter and polydispersity of the nanoparticles. Zeta potential and FTIR absorbance were unaffected, while XRD suggested a greater disarray of chain alignment in the nanoparticle matrix. Under the transmission electron microscope (TEM), freshly prepared nanoparticles were dense spherical structures which became fragmented after ultrasonication for 10 min at amplitude of 80. Untreated nanoparticle formulation turned turbid upon storage for 3 weeks at ambient conditions due to substantial swelling of the nanoparticles. Ultrasonicated nanoparticle formulation remained clear on storage. Although the particles had also swelled, they were no longer spherical, assuming instead an irregular shape with branching arms. In conclusion, high-intensity ultrasonication induced considerable damage on the chitosan nanoparticles which could affect their function as drug carriers.

Adjuvants, Pharmaceutic↗
PubMed1997

Preparation, characterization and cytotoxicity of methylmethacrylate copolymer nanoparticles with a permanent positive surface charge.

Methylmethacrylate copolymer nanoparticles containing different cationic comonomers such as N-trimethylammoniumethylmethacrylate (TMAEMC), N-dimethylammoniumethylmethacrylate (DMAEMC), N-trimethylammoniumpropylmethylacrylamide (MAPTAC) or the anionic comonomer sulfopropylmethacrylate (SPM), respectively, were prepared by free radical polymerization. Particle size was determined by photon correlation spectroscopy (PCS), transmission and scanning electron microscopy (TEM, SEM), and surface charge by microelectrophoresis. Pure poly(methylmethacrylate) nanoparticles served as control. Depending on the method, mean diameters of permanently positively-charged nanoparticles MMA-TMAEMC and MMA-MAPTAC were 243 or 207 nm (PCS), 161 or 201 nm (TEM), and 158 or 197 nm (SEM), respectively. Zeta potential examined in demineralized water or NaCl solution was +63.4 or +32.1 mV for MMA-TMAEMC nanoparticles and +49.2 or +32.0 mV for MMA-MAPTAC nanoparticles, respectively. Cytotoxicity of nanoparticles was determined by MTT assay in three different cell cultures including human foreskin fibroblasts (HFF) and two monkey kidney cell lines MA-104 and Vero. Cell viability profiles of TMAEMC and MAPTAC containing nanoparticles were different, showing IC(50) values for MMA-TMAEMC nanoparticles of 189.6+/-11.4 µg/ml (MA-104), 110.9+/-3.1 µg/ml (Vero) and 27.2+/-4.0 µg/ml (HFF). Cell viability at maximum concentration of 500 µg/ml MMA-MAPTAC nanoparticles was 98.3% (Vero), 85.7% (MA-104), or 94.0% (HFF), respectively.

Journal Article↗