Suppressing unspecific cell uptake for targeted delivery using hydroxyethyl starch nanocapsules

Synthesizing nanocarriers with stealth properties and delivering a "payload" to the particular organ remains a big challenge but is the prime prerequisite for any in vivo application. As a nontoxic alternative to the modification by poly(ethylene glycol) PEG, we describe the synthesis of cross-linked hydroxyethyl starch (HES, M(w) 200,000 g/mol) nanocapsules with a size range of 170-300 nm, which do not show nonspecific uptake into cells. The specific uptake was shown by coupling a folic acid conjugate as a model targeting agent onto the surface of the nanocapsules, because folic acid has a high affinity to a variety of human carcinoma cell lines which overexpress the folate receptor on the cell surface. The covalent binding of the folic acid conjugate onto HES capsules was confirmed by FTIR and NMR spectroscopy. The coupling efficiency was determined using fluorescence spectroscopy. The specific cellular uptake of the HES nanocapsules after folic acid coupling into the folate-receptor presenting cells was studied by confocal laser scanning microscopy (CLSM) and flow cytometry.     

Target-specific cellular uptake of taxol-loaded heparin-PEG-folate nanoparticles

To enhance site-specific intracellular delivery against folate receptor, heparin-PEG-folate (H-PEG-F) containing succinylated-heparin conjugated with folate via PEG 1000/3000 spacers has been prepared. Due to covalent strategy, H-PEG-F displays amphiphilic property, which is capable of entrapping a hydrophobic agent, like taxol, to form heparin-PEG-folate-taxol nanoparticles (H-PEG-F-T NPs) in aqueous solution. Hydrophobic agents can be entrapped within the core, while the H-PEG-F conjugates can stabilize the nanoparticles with exposing folate moieties on the surface. The structure of carrier and naoparticles has been characterized by(1)H NMR, and the content of folate and taxol has been quantitatively analyzed by UV method. The morphology and size of H-PEG-F-T NPs have been measured by field emission scanning electron microscopy (FESEM) and dynamic lighting scatter (DLS). All the NPs are in spherical shape and the sizes are less than 200 nm. The sizes of the NPs increases with increasing PEG segment length. By employing the flow cytomery method, the extent of cellular uptake has been comparatively evaluated under various conditions. The results of cellular uptake demonstrate that the cellular uptake of the carrier and the NPs is exceedingly higher for KB-3-1 cells (folate receptor overexpressing cell line) than for A549 cells (folate receptor deficiency cell line); H-PEG-F-T NPs show far greater extent of cellular uptake than that of H-PEG-F conjugates against A549 cells; when the content of folate is fixed at the same value, the extent of cellular uptake for the carrier and NPs ascends with the increase of PEG chain length against KB-3-1 cells. It suggests folate-receptor-mediated endocytosis and formation of nanoparticle and spacer length are considered to coaffect the cellular uptake efficiency of H-PEG-F-T NPs and H-PEG-F conjugates. Flow cytometry analysis depicts that KB-3-1 cells treated with H-PEG-F-T are arrested in the G(2)/M phase of the cell cycle, which states the similar inhibition mechanism as taxol. The strategy based on the formation of H-PEG-F-T NPs could be potentially applied for cancer cell targeted delivery of various therapeutic agents.     

Efficient intracellular delivery of oligonucleotides formulated in folate receptor-targeted lipid vesicles

In this study, a novel lipid vector has been developed for targeted delivery of oligodeoxynucleotides (ODN) to tumors that overexpress folate receptor. This is based on a method developed by Semple et al. (1), which utilizes an ionizable aminolipid (1,2-dioleoyl-3-(dimethylammonio)propane, DODAP) and an ethanol-containing buffer system for encapsulating large quantities of polyanionic ODN in lipid vesicles. Folate is incorporated into the lipid vesicles via a distearoylphosphatidylethanolamine-poly(ethylene glycol) (DSPE-PEG) spacer. These vesicles are around 100-200 nm in diameter with an ODN entrapment efficiency of 60-80%. Folate mediated efficient delivery of ODN to KB cells that overexpress folate receptor. Uptake of folate-targeted lipidic ODN by KB cells is about 8-10-fold more efficient than that of lipidic ODN without a ligand or free ODN. This formulation is resistant to serum. Thus, targeted delivery of ODN via this novel lipid vector may have potential in treating tumors that overexpress folate receptors.     

Synthesis of a folate functionalized PEGylated poly(propylene imine) dendrimer as prospective targeted drug delivery system

Based on fourth generation diaminobutane poly(propylene imine) dendrimer, a novel targeted drug nanocarrier was prepared, bearing protective PEG chains and a folate targeting ligand. As a control a PEGylated derivative without folate was also synthesized. The encapsulation and release properties of these PEGylated derivatives were investigated employing etoposide, an anticancer hydrophobic drug. Enhanced solubility of etoposide was achieved inside the dendrimeric scaffold which was subsequently released in a controlled manner. These properties coupled with specificity towards the folate receptor and the low toxicity render folate functionalized PEGylated poly(propylene imine) dendrimer promising candidate for targeted drug delivery.     

Ketal cross-linked poly(ethylene glycol)-poly(amino acid)s copolymer micelles for efficient intracellular delivery of doxorubicin

A biocompatible, robust polymer micelle bearing pH-hydrolyzable shell cross-links was developed for efficient intracellular delivery of doxorubicin (DOX). The rationally designed triblock copolymer of poly(ethylene glycol)-poly(L-aspartic acid)-poly(L-phenylalanine) (PEG-PAsp-PPhe) self-assembled to form polymer micelles with three distinct domains of the PEG outer corona, the PAsp middle shell, and the PPhe inner core. Shell cross-linking was performed by the reaction of ketal-containing cross-linkers with Asp moieties in the middle shells. The shell cross-linking did not change the micelle size and the spherical morphology. Fluorescence quenching experiments confirmed the formation of shell cross-linked diffusion barrier, as judged by the reduced Stern-Volmer quenching constant (K(SV)). Dynamic light scattering and fluorescence spectroscopy experiments showed that shell cross-linking improved the micellar physical stability even in the presence of micelle disrupting surfactants, sodium dodecyl sulfate (SDS). The hydrolysis kinetics study showed that the hydrolysis half-life (t(1/2)) of ketal cross-links was estimated to be 52 h at pH 7.4, whereas 0.7 h at pH 5.0, indicating the 74-fold faster hydrolysis at endosomal pH. Ketal cross-linked micelles showed the rapid DOX release at endosomal pH, compared to physiological pH. Confocal laser scanning microscopy (CLSM) showed that ketal cross-linked micelles were taken up by the MCF-7 breast cancer cells via endocytosis and transferred into endosomes to hydrolyze the cross-links by lowered pH and finally facilitate the DOX release to inhibit proliferation of cancer cells. This ketal cross-linked polymer micelle is promising for enhanced intracellular delivery efficiency of many hydrophobic anticancer drugs.     

Preparation of liquid-core nanocapsules from poly[(ethylene oxide)-co-glycidol] with multiple hydrophobic linoleates at an oil-water interface and its encapsulation of pyrene

A convenient approach is provided to prepare liquid-core nanocapsules by cross-linking an amphiphilic copolymer at an oil-water interface. The hydrophilic copolymer poly[(ethylene oxide)-co-glycidol] was prepared by anionic polymerization of ethylene oxide and ethoxyethyl glycidyl ether first, then the hydroxyl groups on the backbone were recovered after hydrolysis and partly modified by hydrophobic conjugated linoleic acid. The copolymer with multiple linoleate pendants was absorbed at an oil-water interface and then cross-linked to form stable nanocapsules. The mean diameter of the nanocapsule was below 350 nm, and the size distribution was relatively narrow (<0.2) at low concentrations of oil in acetone (<10 mg/mL). The particle size could be tuned easily by variation of the emulsification conditions. The nanocapsule was stable in water for at least 5 months, and the shell maintained its integrity after removal of the oily core by solvent. Pyrene was encapsulated in these nanocapsules, and a loading efficiency as high as 94% was measured by UV spectroscopy.     

Synthesis and biological evaluation of folate receptor-targeted boronated PAMAM dendrimers as potential agents for neutron capture therapy

Successful treatment of cancer by boron neutron capture therapy (BNCT) requires the selective delivery of (10)B to constituent cells within a tumor. The expression of the folate receptor is amplified in a variety of human tumors and potentially might serve as a molecular target for BNCT. In the present study we have investigated the possibility of targeting the folate receptor on cancer cells using folic acid conjugates of boronated poly(ethylene glycol) (PEG) containing 3rd generation polyamidoamine dendrimers to obtain (10)B concentrations necessary for BNCT by reducing the uptake of these conjugates by the reticuloendothelial system. First we covalently attached 12-15 decaborate clusters to 3rd generation polyamidoamine dendrimers. Varying quantities of PEG units with varying chain lengths were then linked to these boronated dendrimers to reduce hepatic uptake. Among all prepared combinations, boronated dendrimers with 1-1.5 PEG(2000) units exhibited the lowest hepatic uptake in C57BL/6 mice (7.2-7.7% injected dose (ID)/g liver). Thus, two folate receptor-targeted boronated 3rd generation polyamidoamine dendrimers were prepared, one containing approximately 15 decaborate clusters and approximately 1 PEG(2000) unit with folic acid attached to the distal end, the other containing approximately 13 decaborate clusters, approximately 1 PEG(2000) unit, and approximately 1 PEG(800) unit with folic acid attached to the distal end. In vitro studies using folate receptor (+) KB cells demonstrated receptor-dependent uptake of the latter conjugate. Biodistribution studies with this conjugate in C57BL/6 mice bearing folate receptor (+) murine 24JK-FBP sarcomas resulted in selective tumor uptake (6.0% ID/g tumor), but also high hepatic (38.8% ID/g) and renal (62.8% ID/g) uptake, indicating that attachment of a second PEG unit and/or folic acid may adversely affect the pharmacodynamics of this conjugate.     

Transmucosal passage of polyalkylcyanoacrylate nanocapsules as a new drug carrier in the small intestine

The enteral absorption of particles has been investigated in the dog using a colloidal drug carrier, polyalkylcyanoacrylate nanocapsules loaded with an iodized oil (Lipiodol), as a tracer for X-ray microprobe analysis in a scanning electron microscope. Nanocapsules are spherical capsules, 100 to 200 nm in diameter, with a continuous polymeric wall surrounding a cavity which encapsulates the drug. Administered in the jejunal lumen, Lipiodol nanocapsules improved the absorption of the tracer as indicated by increased concentration of iodine in the plasma of mesenteric blood. In order to follow nanocapsules at the cellular level, all tissue compartments were preserved in a life-like state by cryofixation and freeze-drying of intestinal biopsies. Nanocapsules appeared in the intestinal lumen close to the mucus, then in intercellular spaces and defects of the mucosa and finally in the lamina propria and blood capillaries; in this latter compartment, the iodine content was four-fold higher than after intra-jejunal administration of Lipiodol emulsion. This complete phenomenon occurred only at the tip of the villi and happened within less than 60 min. We conclude that nanocapsules enhance the rate of absorption of Lipiodol and transport the drug from the intestinal lumen to the vascular compartment using a paracellular pathway. Thus they may be useful as drug carrier for oral administration of many chemicals.     

SYNTHESIS OF FOLATE RECEPTOR-TARGETED AND DOXORUBICIN-COUPLED CHEMOTHERAPEUTIC NANOCONJUGATE AND RESEARCH INTO ITS MEDICAL APPLICATIONS

Folate-targeted drug delivery has become an alternative therapy for the treatment of various cancers. Folate receptors are known to be responsible for cellular accumulation of folate and folate analogs with high binding affinity. The anthracycline antibiotic doxorubicin has a broad spectrum of antineoplastic action and a correspondingly widespread degree of clinical use. In this work, we aimed to prepare a folate receptor-targeted doxorubicin delivery system to achieve minimal effect of doxorubicin on healthy cells and more cytotoxicity of it on tumor cells. Folate–poly(ethylene glycol)–doxorubicin (FOL-PEG-DOX) nanoconjugate was synthesized through this aim and characterized with nuclear magnetic resonance (NMR), zetasizer, and atomic force microscopy (AFM). Doxorubicin release studies were also performed in vitro. The size of FOL-PEG-DOX was 78.84 nm. The results indicated that doxorubicin release rate from the conjugate was faster at pH 5.0 than pH 7.4 and the amide bond between DOX and PEG was more stable at pH 7.4 than pH 5.0. As a consequence, FOL-PEG-DOX nanoconjugate could be a potentially useful delivery system for folate receptor-positive cancer cells.     

Folic acid conjugated amino acid-based star polymers for active targeting of cancer cells

Amino acid-based core cross-linked star (CCS) polymers (poly(L-lysine)(arm)poly(L-cystine)(core)) with peripheral allyl functionalities were synthesized by sequential ring-opening polymerization (ROP) of amino acid N-carboxyanhydrides (NCAs) via the arm-first approach, using N-(trimethylsilyl)allylamine as the initiator. Subsequent functionalization with a poly(ethylene glycol) (PEG)-folic acid conjugate via thiol-ene click chemistry afforded poly(PEG-b-L-lysine)(arm)poly(L-cystine)(core) stars with outer PEG coronas decorated with folic acid targeting moieties. Similarly, a control was prepared without folic acid, using just PEG. A fluorophore was used to track both star polymers incubated with breast cancer cells (MDA-MB-231) in vitro. Confocal microscopy and flow cytometry revealed that the stars could be internalized into the cells, and higher cell internalization was observed when folic acid moieties were present. Cytotoxicity studies indicate that both stars are nontoxic to MDA-MB-231 cells at concentrations of up to 50 μg/mL. These results make this amino acid-based star polymer an attractive candidate in targeted drug delivery applications including chemotherapy.     

Monoolein-based nanocarriers for enhanced folate receptor-mediated RNA delivery to cancer cells

We report the development and characterization of a novel nanometric system for specific delivery of therapeutic siRNA for cancer treatment. This vector is based on a binary mixture of the cationic surfactant dioctadecyldimethylammonium chloride (DODAC) and the helper lipid monoolein (MO). These liposomes were previously validated by our research group as promising non-viral vectors for nucleic acid delivery. In this work, the DODAC:MO vesicles were for the first time functionalized with polyethylene glycol and PEG-folate conjugates to achieve both maximal stability in biological fluids and increase selectivity toward folate receptor α expressing cells. The produced DODAC:MO:PEG liposomes were highly effective in RNA complexation (close to 100%), and the resulting lipoplexes also demonstrated high stability in conditions simulating their administration by intravenous injection (physiological pH, high NaCl, heparin and fetal bovine serum concentrations). In addition, cell uptake of the PEG-folate-coated lipoplexes was significantly greater in folate receptor α positive breast cancer cells (39% for 25?µg/mL of lipid and 31% for 40?µg/mL) when compared with folate receptor α negative cells (31% for 25?µg/mL of lipid and 23% for 40?µg/mL) and to systems without PEG-folate (≈13% to 16% for all tested conditions), supporting their selectivity towards the receptor. Overall, the results support these systems as appealing vectors for selective delivery of siRNA to cancer cells by folate receptor α-mediated internalization, aiming at future therapeutic applications of interest.     

Polyelectrolyte complex micelles composed of c-raf antisense oligodeoxynucleotide-poly(ethylene glycol) conjugate and poly(ethylenimine): effect of systemic administration on tumor growth

An antisense oligodeoxynucleotide (ODN) delivery system based on polyelectrolyte complex (PEC) micelles composed of an ODN-poly(ethylene glycol) (PEG) conjugate and polyethylenimine (PEI) was demonstrated. The PEC micelles having a core/shell structure were spontaneously formed in an aqueous solution by ionic interactions between ODN part in the conjugate and PEI. The ODN/PEI polyelectrolyte complex formed an inner core while PEG chains surrounded it as a shell. The morphology of the micelles was visualized as a separate sphere by atomic force microscopy (AFM). When the micelles containing a c-raf antisense ODN were intravenously administered into tumor-bearing nude mice, significant antitumor activities against human lung cancer were observed. The intravenously injected micelles also showed significantly higher accumulation level in the solid tumor region compared to that of naked ODN.     

Synthesis and grafting of thioctic acid-PEG-folate conjugates onto Au nanoparticles for selective targeting of folate receptor-positive tumor cells

This paper reports the creation of Au nanoparticles (AuNP) that are soluble in aqueous solution over a broad range of pH and ionic strength values and that are capable of selective uptake by folate receptor positive (FR+) cancer cells. A novel poly(ethylene glycol) (PEG) construct with thioctic acid and folic acid coupled on opposite ends of the polymer chain was synthesized for targeting the AuNP to FR+ tumor cells via receptor-mediated endocytosis. These folic acid-PEG-thioctic acid conjugates were grafted onto 10-nm-diameter Au particles in aqueous solution. The resulting folate-PEG-coated nanoparticles do not aggregate over a pH range of from 2 to 12 and at electrolyte concentrations of up to 0.5 M NaCl with particle concentrations as high as 1.5 x 10(13) particles/mL. Transmission electron microscopy was used to document the performance of these coated nanoparticles in cell culture. Selective uptake of folate-PEG grafted AuNPs by KB cells, a FR+ cell line that overexpress the folate receptor, was observed. AuNP uptake was minimal in cells that (1) do not overexpress the folate receptor, (2) were exposed to AuNP lacking the folate-PEG conjugate, or (3) were co-incubated with free folic acid in large excess relative to the folate-PEG grafted AuNP. Understanding this process is an important step in the development of methods that use targeted metal nanoparticles for tumor imaging and ablation.     

Receptor-mediated gene delivery by folate-PEG-baculovirus in vitro

Gene delivery using baculovirus is a promising approach for efficient and safe gene therapy compared with animal viruses. However, obstacles of baculovirus-mediated gene delivery include inactivation of baculovirus in human serum and whole blood and the lack of specificity in targeted delivery. Therefore, chemical modification of the viral surface with poly(ethylene glycol) (PEG) and a targeting ligand, such as folate, is necessary for stable and targeted gene delivery via receptor-mediated endocytosis. In this study, folate-PEG (F-PEG) was attached on the baculovirus surface to obtain efficiency and specificity of gene delivery. Composition of F-PEG and degree of capsid modification with F-PEG was determined using (1)H nuclear magnetic resonance ((1)H NMR) and fluorescamine assay, respectively. Folate-PEG-Baculovirus (F-P-Bac) showed enhanced transduction efficiency compared to PEG-Baculovirus (P-Bac) in folate receptor (FR)-positive KB cells. Moreover, this enhanced transduction was not observed in FR-negative HepG2 cells. Presence of free folate in the medium blocked the transduction of F-P-Bac, whereas transduction efficiency of P-Bac in the presence or absence of free folate was not changed significantly. This study thus suggests that F-P-Bac can be used as a receptor-mediated gene delivery system.     

Temperature-sensitive pluronic/poly(ethylenimine) nanocapsules for thermally triggered disruption of intracellular endosomal compartment

Pluronic hydrogel nanoparticles cross-linked with poly(ethylenimine) (PEI) were synthesized by a modified emulsification/solvent evaporation method. Pluronic F-127 preactivated at the terminal group with p-nitrophenyl chloroformate was dissolved in dichloromethane, and the organic solution was emulsified in deionized water containing PEI by sonication. Primary amine groups of PEI in the aqueous phase were conjugated and/or cross-linked with activated Pluronic F-127 in the vicinity of the water/dichloromethane interface, resulting in the formation of shell-cross-linked Pluronic/PEI nanocapsules. Pluronic/PEI nanocapsules exhibited a volume transition behavior over a temperature range of 24-33 degrees C. The thermally reversible swelling/deswelling of Pluronic/PEI nanocapsules was caused by temperature-dependent hydrophobic interaction of cross-linked and/or grafted Pluronic polymer chains in the nanocapsules. Pluronic/PEI nanocapsules were utilized to break up intracellular endosomal compartments by swelling-induced destabilization of the endosomal membrane triggered by a cold-shock treatment.     

Folate receptor targeted delivery of polyelectrolyte complex micelles prepared from ODN-PEG-folate conjugate and cationic lipids

A polyelectrolyte complex micelle (PECM)-based delivery system for targeting folate (FOL) receptor overexpressing tumor cells is demonstrated using poly(ethylene glycol) (PEG)-conjugated oligonucleotide (ODN). The tumor targeting property was conferred to the PECM by tethering a folate moiety to the distal end of the PEG segment in an anti-sense green fluorescent protein (GFP) ODN-PEG conjugate. Nanoscale PECMs were spontaneously produced from ionic interactions between the ODN-PEG-FOL conjugate and a cationic lipid, lipofectamine (Lf). When treated with FOL receptor overexpressing cells (KB), the PCEMs caused a significant reduction in GFP expression in a dose-dependent manner. This effect was not observed in FOL receptor deficient cells (A549). The enhanced transfection of ODN-PEG-FOL/Lf PECMs to KB cells was caused by FOL receptor mediated endocytosis. The efficiency of target-specific gene suppression by ODN-PEG-FOL/Lf PECMs was maintained even in the presence of 10% fetal bovine serum in the transfection medium.     

Nanoparticle-based biocompatible and targeted drug delivery: characterization and in vitro studies

Paclitaxel nanoparticles (PAX NPs) prepared with the size of 110 ± 10 nm and ζ potential of -40 ± 3 mV were encapsulated in synthetic/biomacromolecule shell chitosan, dextran-sulfate using a layer-by-layer self-assembly technique. Zeta potential measurements, analysis of X-ray photoelectron spectroscopy, and scanning electron microscopy confirmed the successful adsorption of each layer. Surface modifications of these core-shell NPs were performed by covalently conjugating with poly(ethylene glycol) (H(2)N-PEG-carboxymethyl, M(w) 3400) and fluorescence labeled wheat germ agglutinin (F-WGA) to build a biocompatible and targeted drug delivery system. 32% of PAX was released from four bilayers of biomacromolecule assembled NPs within 8 h as compared with >85% of the drug released from the bare NPs. Moreover, high cell viability with PEG conjugation and high binding capacity of WGA-modified NPs with Caco-2 cells were observed. This biocompatible and targeted NP-based drug delivery system, therefore, may be considered as a potential candidate for the treatment of colonic cancer and other diseases.     

具有佐剂效果的海藻酸钙纳米胶囊制备

利用海藻酸多糖酸沉淀性质并结合乳化技术,本研究开发了一种酸沉淀诱导相变制备海藻酸钙纳米胶囊的新颖方法,并通过改变海藻酸钠溶液和表面活性剂浓度获得了最小平均水动力学直径在300 nm以下的球形凝胶颗粒,粒径分布均一,表面呈负电性。细胞培养实验结果表明,该海藻酸钙纳米胶囊对人外周血来源未成熟树突状细胞的成熟有与肿瘤坏死因子?（TNF-?）和细菌脂多糖（LPS）相当效力的刺激作用。蛋白质分子可通过共价偶联方式负载。该海藻酸钙纳米胶囊在新型疫苗设计、细胞治疗和靶向给药等方面具有重要的应用潜力。     

Functionalized amphiphilic hyperbranched polymers for targeted drug delivery

Amphiphilic hyperbranched core-shell polymers with folate moieties as the targeting groups were synthesized and characterized. The core of the amphiphilic polymers was hyperbranched aliphatic polyester Boltorn H40. The inner part and the outer shell of the amphiphilic polymers were composed of hydrophobic poly(epsilon-caprolactone) segments and hydrophilic poly(ethylene glycol) (PEG) segments, respectively. To achieve tumor cell targeting property, folic acid was further incorporated to the surface of the amphiphilic polymers via a coupling reaction between the hydroxyl group of the PEG segment and the carboxyl group of folic acid. The polymers were characterized by (1)H NMR, (13)C NMR, and combined size-exclusion chromatography and multiangle laser light scattering analysis. The nanoparticles of the amphiphilic polymers prepared by dialysis method were characterized by transmission electron microscopy and particle size analysis. Two antineoplastic drugs, 5-fluorouracil and paclitaxel, were encapsulated into the nanoparticles. The drug release property and the targeting of the drug-loaded nanoparticles to different cells were evaluated in vitro. The results showed the drug-loaded nanoparticles exhibited enhanced cell inhibition because folate targeting increased the cytotoxicity of drug-loaded nanoparticles against folate receptor expressing tumor cells.     

TAT Peptide-Conjugated Magnetic PLA-PEG Nanocapsules for the Targeted Delivery of Paclitaxel: <Emphasis Type="Italic">In Vitro</Emphasis> and Cell Studies

Paclitaxel (PTX) and organophilic iron oxide nanocrystals of 7 nm average size were co-encapsulated in the oily core of poly(lactide)-poly(ethyleneglycol) (PLA-PEG) nanocapsules in order to develop magnetically responsive nanocarriers of PTX. The nanocapsules were prepared by a solvent displacement technique and exhibited satisfactory drug and iron oxide loading efficiency, high colloidal stability, and sustained drug release properties. Drug release also proved responsive to an alternating magnetic field. Magnetophoresis experiments showed that the magnetic responsiveness of the nanocapsules depended on their SPION content. The PTX-loaded nanocapsules exhibited comparable to free PTX cytotoxicity against the A549 lung cancer cell line at 24 h of incubation but higher cytotoxicity than free drug at 48 h of incubation. The conjugation of a cysteine-modified TAT peptide (HCys-Tyr-Gly-Arg-Lys-Lys-Arg-Arg-Gln-Arg-Arg-Arg-NH₂) on the surface of the nanocapsules resulted to highly increased uptake of nanocapsules by cancer cells, as well as to profound improvement of their cytotoxicity against the cancer cells. The results obtained justify further investigation of the prospects of these multifunctional PLA-PEG nanocapsules as a targeted delivery system of paclitaxel.