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PubMed2005

Bias-free pneumatic sample injection in microchip electrophoresis.

We have developed a new microfluidic chip capable of accurate metering, pneumatic sample injection, and subsequent electrophoretic separation. The pneumatic injection scheme, enabling us to introduce a solution without sampling bias unlike electrokinetic injection, is based upon the hydrophobicity and wettability of channel surfaces. An accurately metered solution of 10 nL could be injected by pneumatic pressure into a hydrophilic separation channel through Y-shaped hydrophobic valves, which consist of polydimethylsiloxane (PDMS) and fluorocarbon (FC) film layers. We demonstrated the successful pneumatic injection of a red ink solution into the separation channel as a proof of the concept. A mixture of fluorescein and dichlorofluorescein (DCF) could be baseline-separated using a single power source in microchip electrophoresis.

Electrophoresis, Microchip↗

PubMed2004

Break-up, coalescence and catastrophic phase inversion in turbulent contactors.

When a low concentration of immiscible phase is dispersed, break-up in the impeller region controls the drop size. The traditional application of Kolmogoroff's theory of local isotropic turbulence has been moderately successful in relating equilibrium drop sizes to the physical properties and the turbulent flow, with low power number impellers giving smaller drops at equal mean specific energy dissipation rates, [Formula: see text] However, to explain the reduction in drop size at equal [Formula: see text] on scale-up, the concept of intermittency must be introduced leading to a scale-up rule close to constant tip speed. With increasing concentration, coalescence generally becomes important and drop sizes increase. Modelling of coalescence involves collision frequency and coalescence efficiency. The latter is dependent on the type of drop interface, the establishment of which type for a particular system being difficult. The difficulty is compounded since in clean systems, at concentrations of the aqueous phase > approximately 20% by volume, droplets of oil appear in the aqueous drops whilst the converse is not found. At sufficiently high concentrations, where the concept of collision frequency is questionable, catastrophic phase inversion (CPI) occurs because coalescence becomes so high. Anything that enhances coalescence, e.g. surfactants, particles that bridge interfaces, wettable surfaces, bulk flow patterns, encourages CPI to occur at lower concentrations of dispersed phase. Satisfactory models for CPI are not available.

Journal Article↗

PubMed2006

Clinical evaluation of a new multi-purpose disinfecting solution in symptomatic contact lens wearers.

PURPOSE: To evaluate the safety and efficacy of a new multi-purpose disinfecting solution (MPDS) in symptomatic soft contact lens wearers using Group IV soft lenses and compare its performance with that of a marketed MPS. METHODS: This was a 4-week, randomized, concurrently controlled, double-masked, multi-site study involving 362 subjects at 19 investigational sites in the US. Existing Group IV lens wearers, pre-screened to be symptomatic for contact lens-related ocular discomfort, were fitted with a new pair of lenses that matched their pre-study lens brand then randomly assigned to one of two treatment regimens: Regimen 1 (OPTI-FREE RepleniSH MPDS, Alcon Laboratories Inc.) or Regimen 2 (ReNu MultiPlus MPS No Rub Formula, Bausch and Lomb Inc.). At Day 0 (baseline), Days 14 and 28 subjects recorded comfort and ocular symptoms, wearing time, rewetting drop and lens removal frequency, and investigators assessed slit-lamp findings, lens deposits and wettability, and visual acuity. RESULTS: Total corneal staining mean score was significantly lower for the Regimen 1 group at Day 14 (P<or=0.02). Comfort and dryness mean scores were significantly better for Regimen 1 compared to Regimen 2 at Day 28 (P<or=0.02; P<or=0.007) and mean scores for scratchiness and burning were significantly lower at Day 14 (P<or=0.04; P<or=0.01). Significant differences were noted in favor of Regimen 1 on 12 of the 12 Likert questionnaire statements (P<0.05). Average lens wearing time was significantly greater for the Regimen 1 group compared to the Regimen 2 group at Day 14 (P<0.05). Lens deposits were significantly lower with Regimen 1 than with Regimen 2 (P<or=0.02). CONCLUSION: This study shows that the new formulation is safe and efficacious when used by symptomatic Group IV lens wearers. Comfort, ocular signs and symptoms and wearing times in patients experiencing problems with their contact lenses can be influenced by the choice of MPS. Selecting an appropriate lens care product enhances patients' wearing experience, maintains optimal lens performance and may help to prevent drop-out.

Adult↗

PubMed2004

Platelet adhesive resistance of polyurethane surface grafted with zwitterions of sulfobetaine.

A possible approach to improve the blood compatibility of poly(etherurethane)s (PU) involves the covalent attachment of key molecular on its surface. Recently, polymer tailed with zwitterions was found having good blood compatibility. The purpose of present study was to design and synthesis a novel nonthrombogenic biomaterial by modifying the surface of poly(etherurethane) with zwitterions of sulfobetaine via HDI spacer. The films of polyurethane were grafted with sulfobetaine by a three-step procedure. In the first step, the film surfaces were treated with hexamethylene diisocyanate (HDI) in toluene at 50 degrees C in the presence of di-n-butyl tin dilaurate(DBTDL) as a catalyst. The extent of the reaction was measured by ATR-IR spectra; a maximum number of free NCO group was obtained after a reaction time of 2.5 h. In the second step, the primary amine group of N,N-diethylethylenediamine (DEA) or N,N-dimethylethylenediamine (DMA) was allowed to react in toluene with isocyanate groups bound on surface. In the third step, two kinds of sulfobetaines were formed in the surface through the ring-opening reaction between tertiary amine of DMA or DEA and 1,3- propanesultone (PS). The reaction process was monitored with ATR-IR spectra and XPS spectra. The wettability of films was investigated by water contact angle measurement. A platelet adhesion experiment was conducted as a preliminary test to confirm the improved blood compatibility of PU. The number of platelets adhering to PU decreased greatly compared to original after 1 h and 3 h of contact with human plate-rich plasma.

Betaine↗

PubMed2004

Blood compatibility of polyurethane surface grafted copolymerization with sulfobetaine monomer.

Surface modification is an effective way to improve the hemocompatibility and remain bulk properties of biomaterials. Recently, polymer tailed with zwitterions was found having good blood compatibility. In this study, the grafting copolymerization of sulfobetaine onto polyurethane surface was obtained through two steps. In the first step, polyurethane film coupled with vinyl groups was obtained through the reaction between the carboxyl group of acrylic acid (AA) and the NH-urethane group of polyurethane by dicyclohexylcarbodiimide (DCC). In the second step, sulfobetaine was grafted copolymerization on the surface using AIBN as an initiator. The reaction process was monitored with ATR-IR spectra and X-ray photoelectron spectroscopy (XPS) spectra. The wettability of films was investigated by water contact angle measurement. The blood compatibility of the grafted films was evaluated by platelet adhesion in platelet rich plasma (PRP) and protein absorption in bovine fibrinogen (BFG). Low platelet adhesion was observed on the grafted films incubated in PRP for 1 and 3 h, respectively. The protein absorption was reduced on the grafted films after incubated in bovine fibrinogen for 2 h. All of these results revealed that the improved blood compatibility was obtained by grafting copolymerization with zwitterionic monomer of sulfobetaine onto polyurethane film. In addition, introducing vinyl groups onto surface through DCC and AA is a novel method to functionalize polyurethane for further modification.

Acrylates↗

PubMed2004

Chemical graft polymerization of sulfobetaine monomer on polyurethane surface for reduction in platelet adhesion.

Surface modification is an effective way to improve the hemocompatibility and remain bulk properties of biomaterials. Recently, polymer tailored with zwitterions was found having good blood compatibility. In this study, the zwitterionic monomer of sulfobetaine was graft polymerized onto polyurethane (PU) surface in a three-step heterogenous system through the vinyl bonds of acrylic acid (AA) or hydroxyethyl methacrylate (HEMA), which was immobilized with hexamethylene diisocyanate (HDI) beforehand. First, PU was activated with isocyanate groups using HDI as coupling agent. Second, AA or HEMA was introduced through reaction of AA or HEMA with NCO groups bonded on PU surface. Last, zwitterionic monomer of sulfobetain was graft polymerized with vinyl group of AA or HEMA using AIBN as polymerization initiator. The reaction process was monitored with ATR-IR spectra and XPS spectra. Variation of graft yield with temperature and monomer feed concentration was investigated and feasible conditions were optimized. The wettability of films was investigated by water contact angle measurement and water absorbance. Platelet adhesion experiment was conducted as a preliminary test to confirm the improved blood compatibility of PU. The number of platelets adhering to PU decreased greatly comparing with the originals after 1 and 3 h of contact with human plate-rich plasma (PRP).

Acrylates↗

PubMed2005

Surface modification of surface sol-gel derived titanium oxide films by self-assembled monolayers (SAMs) and non-specific protein adsorption studies.

Biological events occurring at the implant-host interface, including protein adsorption are mainly influenced by surface properties of the implant. Titanium alloys, one of the most widely used implants, has shown good biocompatibility primarily through its surface oxide. In this study, a surface sol-gel process based on the surface reaction of metal alkoxides with a hydroxylated surface was used to prepare ultrathin titanium oxide (TiOx) coatings on silicon wafers. The oxide deposited on the surface was then modified by self-assembled monolayers (SAMs) of silanes with different functional groups. Interesting surface morphology trends and protein adhesion properties of the modified titanium oxide surfaces were observed as studied by non-specific protein binding of serum albumin. The surface properties were investigated systematically using water contact angle, ellipsometry, X-ray photoelectron spectroscopy (XPS), and atomic force microscopy (AFM) measurements. Results showed that the surface sol-gel process predominantly formed homogeneous, but rough and porous titanium oxide layers. The protein adsorption was dependent primarily on the silane chemistry, packing of the alkyl chains (extent of van der Waals interaction), morphology (porosity and roughness), and wettability of the sol-gel oxide. Comparison was made with a thermally evaporated TiOx-Ti/Si-wafer substrate (control). This method further extends the functionalization of surface sol-gel derived TiOx layers for possible titanium alloy bioimplant surface modification.

Adsorption↗

PubMed2005

Blood compatibility of thermoplastic polyurethane membrane immobilized with water-soluble chitosan/dextran sulfate.

Water-soluble chitosan (WSC)/dextran sulfate (DS) was immobilized onto the surface of thermoplastic polyurethane (TPU) membrane after ozone-induced graft polymerization of poly(acrylic acid) (PAA). The surface was characterized with contact angle measurement and X-ray photoelectron spectroscopy (XPS). The adsorption of human plasma fibrinogen (HPF) followed the Langmuir adsorption isotherm. The results showed that the surface density of peroxides generated and poly(acrylic acid) (PAA) grafted reached the maximum value at 20 min of ozone treatment. It was found that the WSC- and DS-immobilized amount increased with pH and the molecular weight of WSC. The membrane/water interfacial free energy increased with PAA-grafting and WSC/DS-immobilization, indicating the increasing wettability of TPU membrane. The adsorption of HPF on TPU-WSC/DS membranes could be effectively curtailed and exhibited unfavorable adsorption. Moreover, WSC/DS immobilization could effectively reduce platelet adhesion and prolong the blood coagulation time, thereby membrane improving blood compatibility of TPU membrane. In addition, the in vitro cytotoxicity test of PEC modification was non-cytotoxic according to much low growth inhibition of L929 fibroblasts. Furthermore, TPU-WSC/DS membranes exhibited higher cell viability than native TPU membrane.

Acrylic Resins↗

PubMed2005

Bioactive heparin immobilized onto microfluidic channels in poly(dimethylsiloxane) results in hydrophilic surface properties.

A new composition of heparin coating for microfluidic systems made out of poly(dimethylsiloxane) (PDMS) was developed and evaluated. The coating that consists of a conditioning polyamine layer followed by two heparin/glutaraldehyde layers, resulted in channel surfaces with sufficient wettability to obtain flow of human normal plasma by capillary force alone. Hydrophilic channel walls are a desirable characteristic in microfluidic devices, since alternative pumping mechanisms must otherwise be included into the system. The immobilized heparin showed high antithrombin-binding capacity and a low degree of blood-material interaction. Plasma in contact with heparin-coated PDMS formed no detectable fibrin in a spectrophotometric assay by which plasma in contact with non-treated PDMS showed complete coagulation. The quartz crystal microbalance technique with energy dissipation monitoring (QCM-D) was utilized to obtain detailed information regarding adsorption kinetics and structural properties of the different layers composing the heparin coating.

Blood Flow Velocity↗

PubMed2005

Micropatterning of polystyrene nanoparticles and its bioapplications.

Micropatterning of biomolecules forms the basis of cell culture, biosensor and microarray technology. Currently, the most widely used techniques are photoresist lithography, soft lithography or using robots which all involve multi-step surface modification directly on a planar substrate. Here we report a method to pattern biomolecules through self-assembling polystyrene nanoparticles in arrayed microwells on a solid surface to form well-ordered patterning, followed by attaching biomolecules to the assembled nanoparticles. The formation of colloidal patterns depends on capillary force, surface wettability and physical confinement. This method can be used for micropatterning a variety of biomolecules such as protein and antibody.

Colloids↗

PubMed2006

Does the nanometre scale topography of titanium influence protein adsorption and cell proliferation?

To investigate the influence of titanium films with nanometre scale topography on protein adsorption and cell growth, three different model titanium films were utilized in the present study. The chemical compositions, surface topographies and wettability were investigated by using X-ray photoelectron spectroscopy (XPS), atomic force microscopy (AFM) and water contact angle measurement, respectively. The films share the same surface chemistry but exhibit different topographies on a nanometre scale. Thus, they act as model systems for biological studies regarding surface topography effects. The films were obtained by varying the deposition rate and the film thickness, respectively. These films displayed nanometre scale surface roughness (root mean square roughness, R(rms)) from 2 to 21 nm over areas of 50 microm x 50 microm, with different grain sizes at their surfaces. Albumin and fibrinogen adsorption on these model titanium films were performed in this study. Bicinchoninic acid assay was employed to determine the amount of adsorbed protein on titanium film surfaces. No statistically significant differences, however, were observed for either albumin or fibrinogen adsorption between the different groups of titanium films. No statistically significant influence of surface roughness on osteoblast proliferation and cell viability was detected in the present study.

Adsorption↗

PubMed2006

Surface functionalized titanium thin films: zeta-potential, protein adsorption and cell proliferation.

The relationship between electric charge at a material surface and protein adsorption is essential to understand the mechanism of biological integration of materials with tissues. This study investigated the influence of titanium thin films' surface chemistry and surface electric charge (zeta-potential) properties on protein adsorption and cell proliferation. Titanium thin films were surface functionalized with different functional end groups, such as -CH=CH2, -NH2 and -COOH groups in order to produce surfaces with a variety of electric charge properties. The chemical compositions, electric charges and wettability were investigated by using X-ray photoelectron spectroscopy (XPS), zeta-potential measurements and water contact angle measurements, respectively. XPS revealed the surface functionalization of titanium films with -CH=CH2, -NH2, and -COOH groups, which were converted from -CH=CH2 groups. Ti-COOH samples showed the lowest water contact angles and zeta-potential compared to all other samples investigated in this study. NH2-terminated titanium films displayed intermediate contact angles of 70.3+/-2.5 degrees . Fibrinogen adsorption on titanium films and surface functionalized titanium films were investigated in this study. Ti-COOH samples displayed a lower protein adsorption than all other groups, such as NH2-, -CH=CH2-terminated titanium thin films. A tendency that the lower zeta-potential of the samples, the lower the protein adsorption at their surfaces was observed. In vitro cell proliferation tests were also performed on the different surface functionalized titanium films. NH2-terminated titanium films displayed good cell proliferation and cell viability tendency. However, a lower cell proliferation on COOH-terminated titanium films was observed compared with NH2-terminated titanium films. This effect was attributed to the difference in protein adsorption of these samples.

Adsorption↗

PubMed2006

Adsorption behaviour and surfactant elution of cationic salivary proteins at solid/liquid interfaces, studied by in situ ellipsometry.

Adsorption of the cationic salivary proteins lactoferrin, lactoperoxidase, lysozyme and histatin 5 to pure (hydrophilic) and methylated (hydrophobized) silica surfaces was investigated by in situ ellipsometry. Effects of concentration (</=10 microgml(-1), for lysozyme </=200 microgml(-1)) and dependence of surface wettability, as well as adsorption kinetics and elutability of adsorbed films by buffer and sodium dodecyl sulphate (SDS) solutions were investigated. Results showed that the amounts adsorbed decreased in the order lactoferrin>/=lactoperoxidase>lysozyme>/=histatin 5. On hydrophilic silica, the adsorption was most likely driven by electrostatic interactions, which resulted in adsorbed amounts of lactoferrin that indicated the formation of a monolayer with both side-on and end-on adsorbed molecules. For lactoperoxidase the adsorbed amounts were somewhat higher than an end-on monolayer, lysozyme adsorption showed amounts corresponding to a side-on monolayer, and histatin 5 displayed adsorbed amounts in the range of a side-on monolayer. On hydrophobized substrata, the adsorption was also mediated by hydrophobic interactions, which resulted in lower adsorbed amounts of lactoferrin and lactoperoxidase; closer to side-on monolayer coverage. For both lysozyme and histatin 5 the adsorbed amounts were the same as on the hydrophilic silica. The investigated proteins exhibited fast adsorption kinetics, and the initial kinetics indicated mass transport controlled behaviour at low concentrations on both types of substrates. Buffer rinsing and SDS elution indicated that the proteins in general were more tightly bound to the hydrophobized surface compared to hydrophilic silica. Overall, the surface activity of the investigated proteins implicates their importance in the salivary film formation.

Adsorption↗

PubMed2026

Integrated experimental and bioinformatics analysis reveals ECM-integrin and redox signaling associated with PMMA/NiO nanocomposites for craniofacial applications.

BACKGROUND: Poly(methyl methacrylate) (PMMA) is widely used in dental and craniofacial applications; however, its clinical performance is limited by poor surface wettability, moderate mechanical strength, and restricted biological activity. Integrating nanomaterial engineering with computational biology offers an opportunity to better understand biomaterial-cell interactions and support the rational design of functional biomaterials. METHODS: Nickel oxide (NiO) nanoparticles were synthesized via chemical precipitation and incorporated into PMMA to fabricate nanocomposites. Physicochemical characterization included contact angle measurements, Fourier-transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDX), and Vickers hardness testing. Biocompatibility was evaluated using zebrafish embryo developmental assays. To explore biological processes potentially associated with biomaterial-cell interactions, bioinformatics analyses including Gene Ontology (GO), Kyoto Encyclopedia of Genes and Genomes (KEGG), and STRING protein-protein interaction (PPI) network analyses were performed. RESULTS: Incorporation of NiO nanoparticles improved the surface and mechanical properties of PMMA, reducing the contact angle from 105.35° to 90.46° and increasing Vickers hardness compared with unmodified PMMA. Structural and morphological analyses confirmed successful synthesis and homogeneous nanoparticle incorporation. Zebrafish embryo studies demonstrated minimal developmental toxicity, supporting the biocompatibility of the nanocomposite. Bioinformatics analyses identified significant enrichment of pathways related to extracellular matrix organization, cell adhesion, focal adhesion, PI3K-Akt signaling, and oxidative stress regulation. Protein-protein interaction analysis revealed highly interconnected networks associated with ECM-integrin signaling and redox homeostasis, highlighting biological processes potentially associated with biomaterial-cell communication. CONCLUSIONS: PMMA/NiO nanocomposites exhibited improved physicochemical performance and favorable biocompatibility characteristics. The integration of experimental characterization with bioinformatics and network-based analyses provides a systems-level perspective on biomaterial-associated cellular processes and identifies ECM-integrin signaling and oxidative stress-related pathways as candidate biological processes for future experimental validation. These findings support the continued development of PMMA/NiO nanocomposites for oral and craniofacial biomedical applications.

Nanocomposites↗

PubMed2004

Does plasma irradiation improve shear bond strength of acrylic resin to cobalt-chromium alloy?

OBJECTIVES: Plasma treatment leads to surface modification such as the improved wettability of dental materials. Studies have suggested that plasma treatment may bring about an improvement in the shear bond strength between cobalt-chromium alloy and self-curing acrylic resin. METHODS: Forty-eight cobalt-chromium alloy specimens were randomly divided into four groups (each of the groups consisted of 12 specimens); air abrasion, adhesive primer, adhesive primer after air abrasion, or after plasma irradiation. A self-curing acrylic resin, 2 mm thick and 3.6 mm in diameter, was processed on all specimens before storage in distilled water at 37 degrees C for 24 h. Shear bond strength values were determined at a crosshead speed of 0.5 mm/min. Data was statistically analyzed using Scheffé's test. RESULTS: Adhesive primer clearly increased the shear bond strength compared with air abrasion (p < 0.05). The synergy of air abrasion and adhesive primer greatly increased the shear bond strength, showing a five-fold increase over air abrasion, or one and a half-fold over adhesive primer. A similar tendency in increase was observed in the adhesive primer after plasma treatment, but to a lower degree. Adhesive primer after plasma treatment showed half the shear bond strength of the treatment of adhesive primer after air abrasion (p < 0.05). Moreover, adhesive primer after plasma treatment showed a lower shear bond strength than adhesive primer alone although the difference was not statistically significant. SIGNIFICANCE: Plasma treatment does not improve adhesion between cobalt-chromium alloy and self-curing acrylic resin.

Acrylic Resins↗

PubMed2006

Surface energy components of a dye-ligand immobilized pHEMA membranes: effects of their molecular attracting forces for non-covalent interactions with IgG and HSA in aqueous media.

In the present paper, we report the study of the adsorption behaviour of human immunoglobulin G (IgG), human serum albumin (HSA) and polyethylenimine (PEI) onto surfaces of Procion Green HE-4BD (PG) immobilized poly(hydroxyethylmethacrylate) (pHEMA) membranes. The adsorption behaviour of the IgG and HSA onto surfaces of the PG-PEI complexed membrane was also studied. Surface wettability and hydrophilicity of all the membranes were investigated by static contact angle measurements. The measurements of the contact angle to various test liquids, i.e., water, glycerol, formamide, diiodomethane (DIM) and ethylene glycol on the investigated membranes were made by sessile drop method. In accordance to the Young equation, the smaller the surface tension of the test liquid, the smaller becomes the contact angles measured on all the investigated membranes surfaces. The highest contact angles were obtained with water, whereas ethylene glycol gave the lowest contact angles for all the tested membranes. Component and parameters of the surface free energy of all the investigated membranes were calculated from measured contact angle values using two methods (the geometric mean by Fowkes and acid-base by van Oss). HSA adsorption was enhanced after complexation of PEI with the immobilized dye-ligand. The adsorption of proteins and PEI significantly changed both the contact angles and component of surface free energies of the investigated membranes.

Adsorption↗

PubMed2005

Enhancement of dissolution rate of poorly-soluble active ingredients by supercritical fluid processes. Part I: Micronization of neat particles.

In this first of two articles, we discuss some issues surrounding the dissolution rate enhancement of poorly-soluble active ingredients micronized into nano-particles using several supercritical fluid particle design processes including rapid expansion of supercritical solutions (RESS), supercritical anti-solvent (SAS) and particles from gas-saturated solutions/suspensions (PGSS). Experimental results confirm that dissolution rates do not only depend on the surface area and particle size of the processed powder, but are greatly affected by other physico-chemical characteristics such as crystal morphology and wettability that may reduce the benefit of micronization.

Chromatography, Supercritical Fluid↗

PubMed2005

Poly(ethylene oxide)-modified poly(epsilon-caprolactone) nanoparticles for targeted delivery of tamoxifen in breast cancer.

This study was carried out to evaluate and compare the biodistribution profile of tamoxifen when administered intravenously (i.v.) as a simple solution or when encapsulated in polymeric nanoparticulate formulations, with or without surface-stabilizing agents. Tamoxifen-loaded, poly(ethylene oxide)-modified poly(epsilon-caprolactone) (PEO-PCL) nanoparticles were prepared by solvent displacement process that allowed in situ surface modification via physical adsorption of poly(ethylene oxide)-poly(propylene oxide)-poly(ethylene oxide) (PEO-PPO-PEO) triblock polymeric stabilizer (Pluronic). The nanoparticles were characterized for particle size and surface charge. Presence of PEO chains on nanoparticle surface was ascertained by electron spectroscopy for chemical analysis (ESCA). In vivo biodistribution studies were carried out in Nu/Nu athymic mice bearing a human breast carcinoma xenograft, MDA-MB-231 using tritiated [(3)H]-tamoxifen as radio-marker for quantification. PEO-PCL nanoparticles with an average diameter of 150-250 nm, having a smooth spherical shape, and a positive surface charge were obtained with the formulation procedure. About 90% drug encapsulation efficiency was achieved when tamoxifen was loaded at 10% by weight of the polymer. Aqueous wettability, suspendability, and ESCA results showed surface hydrophilization of the PCL nanoparticles by the Pluronics. The primary site of accumulation for the drug-loaded nanoparticles after i.v. administration was the liver, though up to 26% of the total activity could be recovered in tumor at 6h post-injection for PEO-modified nanoparticles. PEO-PCL nanoparticles exhibited significantly increased level of accumulation of the drug within tumor with time as well as extended their presence in the systemic circulation than the controls (unmodified nanoparticles or the solution form). Pluronic surfactants (F-68 and F-108) presented simple means for efficient surface modification and stabilization of PCL nanoparticles to achieve preferential tumor-targeting and a circulating drug reservoir for tamoxifen.

Animals↗