Presence Of Copolymer Research Articles

Water Soluble Dual Responsive Star Copolymer for Encapsulation of Hydrophobic Dye Molecules

SummarySynthesis of water soluble thermo and pH responsive 3‐arm star shaped random copolymer of diethylene glycol methyl ether methacrylate (DEGMEM) and N, N diethylaminoethyl methacrylate (DEAEMA) is carried out by ATRP technique. The synthesized copolymer is characterized by 1H NMR spectroscopy and gel permeation chromatography (GPC). The dual stimuli responsive behavior of the synthesized block copolymers is demonstrated using dynamic light scattering (DLS) and fluorescence spectroscopy. The copolymer is insoluble in water at pH 9.2 which is attributed to the hydrophobicity of −NEt2 groups but at lower pH (pH 4 & 7) water solubility is observed due to protonation. Aggregation and dissociation behavior is only observed at pH 7 when the temperature is increased over 35 °C. Heating of the aqueous solution of the copolymer in presence of hydrophobic fluorescent molecule ‘Nile red’ over 35 °C shows a sharp increase in fluorescence intensity which again decreases with lowering of pH indicating temperature triggered encapsulation and pH triggered release of it. The increased hydrophobicity of −NEt2 groups ensure aggregated structure at pH 7 over 35 °C. This is very much important in view of loading of hydrophobic molecules within the polymer scaffold in the pH range that remains in blood stream at physiological conditions.

Preparation and characterization of films made of poly(l-lactic acid)/poly(l-lactic acid) grafted maleic anhydride/epigallocatechin gallate blends for antibacterial food packaging

The antimicrobial activity of films made of poly(l-lactic acid)/poly(l-lactic acid) grafted maleic anhydride(copolymer)/epigallocatechin gallate(EGCG) blend was determined. The effect of epigallocatechin gallate incorporation (0.03, 0.5, 5, and 10 wt%) as a natural antibacterial was determined by direct contact, solid and liquid culture media. The film antimicrobial activity was evaluated against two bacteria (gram-negative: Pseudomonas spp.; gram-positive: Staphylococcus aureus). The copolymer was prepared and characterized by Fourier transform infrared analysis and Molau test. Furthermore, the degree of grafting was determined. The epigallocatechin gallate migration profile through the films were determined and the minimum epigallocatechin gallate concentration in films required to show antibacterial activity was evaluated. The results showed that only the films with 10 wt% epigallocatechin gallate significantly affected ( p < 0.05) the cell morphology and inhibited the growth of S. aureus (56% with copolymer and 55% inhibition without copolymer) and Pseudomonas spp. (28% inhibition, with and without copolymer). Incorporating copolymer inhibited the growth of Pseudomonas spp. and induced morphological changes in S. aureus. The diffusion coefficient was dependent on the presence of copolymer, which increased the epigallocatechin gallate release rate. Incorporating epigallocatechin gallate and copolymer modified the film properties. Fourier transform infrared analysis indicated hydrogen bonds which were attributed to the interaction between copolymer and epigallocatechin gallate. The results demonstrate the potential application of poly(l-lactic acid) (biodegradable polymer) and copolymers in active packaging, as well as the importance of incorporating epigallocatechin gallate as a natural antibacterial agent.

Thermal stability and flammability of ethylene vinyl acetate copolymers in presence of nanoclay and a halogen‐free flame retardant

In this study, thermal stability behavior and flammability of ethylene‐vinyl‐acetate (EVA) copolymers containing organo‐modified nanoclay particles (Cloisite 15A) and ammonium polyphosphate (APP) along with pentaerythritol (PER), as halogen‐free flame retardants, were investigated. Transmission electron microscopy (TEM) and small‐angle X‐ray scattering (SAXS) were employed for evaluation of the level of dispersion of nanosheets within the EVA matrix. Moreover, thermal stability behavior and flammability of the samples were studied using thermogravimetric analysis (TGA), cone calorimetry thermometer (CCT) and limiting oxygen index (LOI). The obtained results from TEM and SAXS showed that nanosheets exhibited a rather proper level of dispersion within the EVA matrix. According to TGA and CCT results, despite improving the thermal stability and flame retardancy of EVA due to incorporation of the individual additives, a considerable synergistic effect was observed upon simultaneous use of clay nanosheets and the flame retardants. Such synergistic effect was explained by the physical mechanism of the solid phase due to the increased residual ash resulted from combustion of the samples containing flame retardants and clay nanosheets. While clay nanosheets had no significant effect on the LOI of EVA, the halogen‐free flame retardants substantially increased the LOI of EVA. J. VINYL ADDIT. TECHNOL., 23:E92–E98, 2017. © 2016 Society of Plastics Engineers

Novel polymeric micelles for drug delivery: Material characterization and formulation screening

A rising number of new chemical entities that exhibit only poor aqueous solubility are identified in drug discovery processes. Polymeric micelles composed of block copolymers (BP) facilitate the delivery of such lipophilic molecules in drug therapy. Consequently, a rational screening and selection procedure for novel BP was established. Further, the interplay of polymer structure, micelle formation and drug binding was studied. Therefore seven polymers (BP001 to BP007) were synthesized from different monomer compositions resulting in nanocarriers varying in surface decoration and lipophilicity. These polymers were characterized by H1-NMR and SEC. The molecular weight was ranging between 13 and 37kDa. The critical micelle concentration and micellar integrity in presence of human plasma were determined. Micelles were loaded with dexamethasone and characterized with regards to their size, morphology and surface charge. Polymeric micelles with a size of 49.21–236.37nm were obtained. A half-life of 11h was determined for five of the copolymers in presence of human plasma. Two nanocarrier formulations (BP006 and BP007) were exhibiting optimal micellar integrity in vitro and a modified release profile under biorelevant conditions. Strongest drug-polymer interaction was observed for nanocarrier compositions providing benzyl and carboxylic groups and were composed of BP006 and BP007.

Gastroretentive Drug Delivery System of Famotidine: Formulation and In Vitro Evaluation of Oil Entrapped Calcium Pectinate Gel Beads

In the present research envisaged was to prepare gastroretentive beads to increase the retention time in stomach and to modulate the release pattern from the gel beads. The aim of the research work to study the compatibility between drug and other polymers by differential scanning calorimetric analysis, preparation of cod liver oil entrapped calcium pectinate gel beads of famotidine by emulsion gelation method and its evaluation. The gel beads were prepared by employing low methoxy pectin with degree of esterification less than 50% alone and with hydrophilic co polymers carbopol 934P, hydroxypropyl methylcellulose K15M and polycarbophil to study the effect of these co polymers on drug release. The prepared gel beads were subjected for various evaluations like topographical study of whole and dissected bead, percent drug entrapment efficiency, buoyancy and in vitro drug release study in conventional and modified flow through dissolution methods. The prepared beads showed ideal buoyancy, low methoxy pectin gel matrix could not sustain the drug release and presence of co polymers demonstrated sustained release. These observations suggested that cod liver oil entrapped calcium pectinate beads were promising as a carrier for intragastric floating drug delivery of famotidine.

Inhibition of β-amyloid peptide self-assembly and cytotoxicity by poly(LVFF-co-β-amino ester).

The β-amyloid (Aβ) peptide plays an important role in the onset and progress of Alzheimer's disease (AD). Therefore, studies on inhibiting fibril formation and thus neurotoxicity of Aβ could be beneficial for the prevention and treatment of AD. We report a convenient synthetic approach for one-pot preparation of poly-(β-amino ester) copolymerized with the GGLVFF peptide, which is based on the frequently used inhibitor LVFF. The copolymer was found to efficiently inhibit the aggregation and fibrillation of Aβ42 by using fluorescence assay and atomic force microscopy. Reduced β-sheet formation of Aβ42 peptide after addition of copolymer was observed by circular dichroism. Furthermore, the cell viability assay confirmed that the toxicity of Aβ42 for SH-SY5Y cells was markedly reduced in the presence of copolymer. This could be beneficial for AD prevention and treatment and also for the molecular design of inhibitory agents for other amyloidoses.

Condensed Mode Cooling for Ethylene Polymerization: Part II. The Effect of Different Condensable Comonomers and Hydrogen on Polymerization Rate

A systematic analysis methodology is proposed in order to be able to evaluate the role and the significance of the impact of the physical and chemical phenomena during the gas phase ethylene copolymerization in presence of 1‐pentene and 1‐hexene comonomers in the gas phase composition. In addition, the effect of inert n‐hexane on the instantaneous rate of gas phase ethylene polymerization in the absence and presence of 1‐hexene comonomer and hydrogen is investigated. This, in turn, provides a novel insight on the counter‐effects of the physical and chemical phenomena taking place simultaneously during the gas phase processes for ethylene polymerization in the industrially relevant conditions. image

PEG 400/Paraffin oil non‐aqueous emulsions stabilized by PBut‐Block‐P2VP block copolymers

ABSTRACTFor the preparation of PEG 400 in paraffin oil non‐aqueous biocompatible emulsions, the stabilization efficiency was compared for two well‐defined poly(butadiene)‐block‐poly(2‐vinylpyridine) (PBut‐block‐P2VP) block copolymers, with similar molecular weights but different compositions. The PBut128‐block‐P2VP50 and PBut189‐block‐P2VP37 samples, designated as copolymer A and B, respectively, are self‐organized in paraffin oil as micelles with a P2VP core and a PBut corona. The PEG 400/paraffin oil emulsion characteristics were determined as a function of the copolymers concentrations and phase ratios. Higher static and shear stabilities were obtained for emulsions stabilized by copolymer B than for those obtained in the presence of copolymer A. A further difference concerns the droplet size, relative viscosity, and loss modulus values obtained at a given dispersed phase volume fraction. At constant copolymer concentrations, it appeared that copolymer B, with a longer PBut sequence, is a more efficient emulsifier and stabilizer than copolymer A. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015, 132, 41390.

Preparation of electrospun electroactive nanofibers of aniline/2-hydroxyethyl methacrylate/ε-caprolactone brush copolymer blended with polycaprolactone

Brush copolymer of poly (aniline)-g-poly (2-hydroxyethyl methacrylate-g-poly (e-caprolactone)) (PANI-g-P (HEMA-g-PCL)) was synthesized via ring-opening polymerization of e-caprolactone (CL) initiated by poly (aniline)-g-poly (2-hydroxyethyl methacrylate) (PANI-g-PHEMA) macromolecular initiator. The macroinitiator was synthesized by atom transfer radical polymerization (ATRP) of 2-hydroxyethyl methacrylate using a polyaniline backbone. Both macroinitiator and graft copolymer were characterized by FTIR and 1H NMR spectroscopy. The thermal behavior, morphology, and electroactivity of brush copolymer were also investigated by thermogravimetric analysis (TGA), scanning electron microscopy (SEM), and cyclic voltammetry (CV), respectively. Uniform nanofibers consisting of blends of (PANI-g-P (HEMA-g-PCL)) copolymer and polycaprolactone (PCL) 10 % with feed ratios of (50/50), (40/60) and (30/70) were prepared using the electrospinning technique. The cyclic voltammetry measurement of blends confirmed the preparation of electroactive nanofibers. The presence of copolymer enhanced the spinnability of solution and significantly reduced the bead formation. This novel system opens up new and interesting opportunities for applications such as electroactive scaffold for tissue engineering.

Preparation and characterization of stimuli-responsive hydrophilic polysulfone membrane modified with poly (N-vinylcaprolactam-co-acrylic acid)

Novel polysulfone (PSF) ultrafiltration membranes with pH and thermo sensitivity were prepared using the copolymer poly (N-vinylcaprolactam-co-acrylic acid) (poly (VCL-co-AA)) as an additive. The copolymer was synthesized by free radical solution polymerization, and directly blended in membrane casting solution to prepare the asymmetric membranes by phase inversion method. The presence of copolymer in blended membranes was confirmed by comparing IR spectra of plain PSF membrane and blended PSF membrane. The morphology and structure of the resulting membranes were observed by scanning electron microscope (SEM) and field emission scanning electron microscope (FESEM). The membranes were characterized in terms of pure water flux (PWF), hydraulic permeability and hydrophilicity. PWF increased from 1 to 18.8L/m2h, when wt.% of copolymer increases from 0 to 2.5. Similarly, water contact angle decreased from 76° to 58°. The blended membranes showed evident of pH and thermo sensitivity. The stimuli responsive behaviour of membranes was also investigated in terms of pH and temperature. In addition, solution of bovine serum albumin (BSA) was used to study the permeation and antifouling performance of prepared membranes. A significant increase in BSA flux (from 0.061L/m2h for plain membrane to 3.37L/m2h for membrane with 6 wt.% of copolymer) and decrease in membrane fouling was observed.

Stability of negatively charged platelets in calcium-rich anionic copolymer solutions.

Controlling the stability of anisotropic particles is key to the development of advanced materials. Here, we report an investigation, by means of mesoscale molecular dynamics simulations, of the stability and structural change of calcium-rich dispersions containing negatively charged nanoplatelets, neutralized by calcium counterions, in the presence of either comb copolymers composed of anionic backbones with attached neutral side chains or anionic-neutral linear block copolymers. In agreement with experimental observations, small stacks of platelets (tactoids) are formed, which are greatly stabilized in the presence of copolymers. In the absence of polymers, tactoids will grow and aggregate strongly due to large attractive Ca(2+)-Ca(2+) correlation forces. Unlike comb copolymers which only adsorb on the external surfaces, block copolymers are found to intercalate between the platelets. The present results show that the stabilization is the result of a free energy barrier induced by the excluded volume of hydrophilic chains, while the intercalation is due to bridging forces. More generally, the results shed new light on the recent finding of the first hybrid cementitious mesocrystal.

Preparation and characterization of novel pegylated hydrophilic pH responsive polysulfone ultrafiltration membrane

In this work, novel cross linked pegylated functional copolymer poly (acrylic acid-co-polyethylene glycol methyl ether methacrylate) was prepared from AA and PEGMA, via precipitation polymerization using toluene as solvent. The copolymer was directly blended with polysulfone (PSF) using N-methylpyrrolidone (NMP) as solvent to prepare flat sheet polymeric membrane by the phase inversion method. Presence of copolymer in blended membrane was confirmed by Fourier transform infrared-attenuated total reflectance (FTIR-ATR) spectroscopy. Blended membranes showed enhanced pore density, pure water flux and hydrophilicity. Cross sectional morphology of the membranes was changed significantly with higher wt% of the copolymer. Contact angle and hydraulic permeability of modified membrane with 7wt% of copolymer were 48.7° and 0.794L/m2hkPa compared to 63.2° and 0.353L/m2hkPa respectively, for unmodified membrane. The blended membranes also showed evidence of pH sensitivity compared to unmodified membrane. For membrane modified with 7wt% of the copolymer, hydraulic permeability was increased from 0.355 to 0.794L/m2hkPa when pH was changed from 11 to 2. Finally, fouling resistance behavior of modified membrane was studied by bovine serum albumin protein separation study. Modified membrane achieved a maximum of around 90% flux recovery ratio after bovine serum albumin (BSA) separation, which is remarkably higher compared to 37% flux recovery ratio of unmodified membrane. Effect of pH for BSA rejection on different membranes was also studied at pH 2, pH 7 and pH 11. It was found that modified membranes had almost same rejection at pH 7 and pH 11, but rejection was much lower at pH 2.

Cationic Comb-Type Copolymer Excludes Intercalating Dye from DNA Without Inducing DNA Condensation

The interaction of a single molecule of DNA with cationic comb-type copolymers has been observed using a flow-stretch assay. We have shown that interaction with a copolymer with a high degree of grafting did not cause a coil-to-globule transition but resulted in shrinkage of the DNA by 20%. In this study, a flow-stretch assay was employed in which changes in length and fluorescence intensity of DNA were simultaneously observed. Upon binding of fluorescent intercalator dyes, the DNA length was extended. In the presence of copolymer, dye binding was inhibited and DNA length was not significantly different than that in the absence of dye and copolymer. Our data suggest that the copolymer does not influence DNA length. Our observation implies that use of the fluorescence dye exclusion assay to estimate DNA condensing activity of polycations must be carefully carried out. Keywords: Coil-to-globule transition, Compaction, DNA, Flow-stretch, Graft copolymer, Inter polyelectrolyte complex, Polycation, Singlemolecular observation.

Chemical force microscopy of stimuli-responsive adhesive copolymers

Atomic force microscopy with chemically sensitive tips was used to investigate the hydrophobic and electrostatic interaction forces of a stimuli-responsive adhesive polymer, and their dynamic changes in response to water immersion and salt concentration. Block copolymer-filled coatings were obtained by incorporating an amphiphilic block copolymer containing a polydimethylsiloxane (PDMS) block and a poly(2-(dimethylamino)ethyl methacrylate) (PDMAEMA) block in a PDMS matrix. Topographic images of fresh samples revealed the presence of nanoscale domains associated with the presence of copolymers, covered by a thin layer of PDMS. Prolonged (30 days) immersion in aqueous solution led to the exposure of the hydrophilic PDMAEMA chains on the surface. Using adhesion force mapping with hydrophobic tips, we showed that fresh samples were uniformly hydrophobic, while aged samples exhibited lower surface hydrophobicity and featured nanoscale hydrophilic copolymer domains. Force mapping with negatively charged tips revealed remarkable salt-dependent force plateau signatures reflecting desorption of polyelectrolyte copolymer chains. These nanoscale experiments show how solvent-induced conformational changes of stimuli-responsive copolymers can be used to modulate surface adhesion.

Polymeric topology and composition constrained polyether–polyester micelles for directional antitumor drug delivery

Amphiphilic linear and dumbbell-shaped poly(ethylene glycol)–poly(lactide-co-glycolide) (PEG–PLGA) copolymers were simply synthesized by the ring-opening polymerization of lactide and glycolide using PEG or tetrahydroxyl-functionalized PEG as the macroinitiator and stannous octoate as the catalyst. The copolymers spontaneously self-assembled into spherical micelles in phosphate-buffered saline at pH 7.4. The self-assembly behavior was dependent on both the polymeric topology and composition. Doxorubicin (DOX), an anthracycline antitumor drug, was loaded into micelles through nanoprecipitation. The in vitro release behavior could be adjusted by regulating the topology or composition of the copolymer, or the pH of the release medium. The effective intracellular DOX release from DOX-loaded micelles was confirmed by confocal laser scanning microscopy and flow cytometry in vitro. DOX-loaded micelles displayed great cellular proliferation inhibition efficacies after incubation for 24, 48 or 72h. The hemolysis ratio of DOX was significantly reduced by the presence of copolymer. These properties indicated that the micelles derived from linear or dumbbell-shaped copolymers were promising candidates as smart antitumor drug carriers for malignancy therapy.

Role of compatibilizer and processing method on the mechanical, thermal and barrier properties of polystyrene/organoclay nanocomposites

This study describes the role of compatibilizer i.e. styrene-maleic anhydride copolymer, its content and compounding method on the properties of polystyrene/clay nanocomposites. The nanocomposites were fabricated using three different methods: (i) simultaneous mixing of all the components i.e. polystyrene, required amounts of styrene-maleic anhydride and nanoclay using twin-screw extruder; (ii) stepwise mixing method i.e. in which blending of polystyrene and organoclay was first done using single-screw extruder and the mixed compound was then blended with varying amounts of styrene-maleic anhydride copolymer using twin-screw extruder and (iii) the effective combination of in situ polymerization of styrene-maleic anhydride copolymer in presence of varying amounts of nanoclay by free radical polymerization followed by melt mixing with polystyrene using twin-screw extruder. The effect of processing method on the micrsostructure of nanocomposites was investigated using X-ray diffraction and transmission electron microscopy. The mechanical properties of nanocomposites such as tensile, flexural and Izod impact strength were measured and discussed in relation to their microstructure. All the fabrication methods yielded nanocomposites with different microstructure ranging from intercalated to exfoliated structure of nanoclay. As expected the stepwise mixing method yielded more intercalated and exfoliated structure as compared to the simultaneous mixing method resulting in improvement in the properties of nanocomposites. On the other hand, combination of in situ polymerization with melt mixing method produced better exfoliation as compared to other two methods. Thermal stability and mechanical strength of polystyrene showed a significant improvement upon incorporation of nanoclay.

Protein-resistant polymer coatings obtained by matrix assisted pulsed laser evaporation

Adsorption of proteins and polysaccharides is known to facilitate microbial attachment and subsequent formation of biofilm on surfaces that ultimately results in its biofouling. Therefore, protein repellent modified surfaces are necessary to block the irreversible attachment of microorganisms. Within this context, the feasibility of using the Poly(ethylene glycol)-block-poly(ɛ-caprolactone) methyl ether (PEG-block-PCL Me) copolymer as potential protein-resistant coating was explored in this work. The films were deposited using Matrix Assisted Pulsed Laser Evaporation (MAPLE), a technique that allows good control of composition, thickness and homogeneity. The chemical and morphological characteristics of the films were examined using Fourier Transform Infrared Spectroscopy (FTIR), contact angle measurements and Atomic Force Microscopy (AFM). The FTIR data demonstrates that the functional groups in the MAPLE-deposited films remain intact, especially for fluences below 0.5Jcm−2. Optical Microscopy and AFM images show that the homogeneity and the roughness of the coatings are related to both laser parameters (fluence, number of pulses) and target composition. Protein adsorption tests were performed on the PEG-block-PCL Me copolymer coated glass and on bare glass surface as a control. The results show that the presence of copolymer as coating significantly reduces the adsorption of proteins.

A novel composite of SiO2-coated graphene oxide and molecularly imprinted polymers for electrochemical sensing dopamine

A novel imprinting route based on graphene oxide (GO) was proposed for preparing a composite of SiO2-coated GO and molecularly imprinted polymers (GO/SiO2–MIPs). In this route, SiO2-coated GO sheets were synthesized in a water–alcohol mixture with sol–gel technique. Prior to polymerization, the vinyl groups were introduced onto the surface of GO/SiO2 through chemical modification with γ-methacryloxypropyl trimethoxysilane (γ-MAPS), which can direct the selective polymerization on the GO/SiO2 surface. Then a novel composite of GO/SiO2–MIPs was successfully obtained by the copolymerization in presence of vinyl groups functionalized GO/SiO2, dopamine (DA), methacrylic acid and ethylene glycol dimethacrylate. The GO/SiO2–MIPs composite was characterized by FTIR, TGA, Raman spectroscopy, SEM and AFM. The properties such as special binding, adsorption dynamics and selective recognition ability using differential pulse voltammetry (DPV) were evaluated. The DPV current response of GO/SiO2–MIPs sensor was nearly 3.2 times that of the non-imprinted polymers (NIPs). In addition, the GO/SiO2–MIPs sensor could recognize DA from its relatively similar molecules of norepinephrine and epinephrine, while the sensors based on GO/SiO2–NIPs and vinyl groups functionalized GO/SiO2 did not have the ability. The GO/SiO2–MIPs sensor had a wide linear range over DA concentration from 5.0×10−8 to 1.6×10−4M with a detection limit of 3.0×10−8M (S/N=3). The sensor based on this novel imprinted composite was applied to the determination of DA in injections and human urine samples with satisfactory results.

On surfactant–polymer association and its effect on the corrosion behavior of carbon steel in cyclohexane propionic acid

The inhibitive properties of cationic surfactant (CS) in the presence of copolymer (CP) at different conditions on the corrosion of carbon steel in cyclohexane propionic acid (CHPA) were studied using polarization, conductivity and EIS measurements. CS acts as an inhibitor for dissolution of carbon steel in CHPA. At low pH (3.4–4) and in the absence of Cl− ion the association between CS and CP is weak. Increasing the pH value (>4) or addition of KCl to the solution increases both CMC value and corrosion inhibition efficiency of CS indicating the association between surfactant and copolymer molecules is increased.

In vitro evaluation of anticancer nanomedicines based on doxorubicin and amphiphilic Y-shaped copolymers

Four monomethoxy poly(ethylene glycol)-poly(L-lactide-co-glycolide)2 (mPEG-P( LA-co-GA)2) copolymers were synthesized by ring-opening polymerization of L-lactide and glycolide with double hydroxyl functionalized mPEG (mPEG-(OH)2) as macroinitiator and stannous octoate as catalyst. The copolymers self-assembled into nanoscale micellar/vesicular aggregations in phosphate buffer at pH 7.4. Doxorubicin (DOX), an anthracycline anticancer drug, was loaded into the micellar/vesicular nanoparticles, yielding micellar/vesicular nanomedicines. The in vitro release behaviors could be adjusted by content of hydrophobic polyester and pH of the release medium. In vitro cell experiments showed that the intracellular DOX release could be adjusted by content of P(LA-co-GA), and the nanomedicines displayed effective proliferation inhibition against Henrietta Lacks’s cells with different culture times. Hemolysis tests indicated that the copolymers were hemocompatible, and the presence of copolymers could reduce the hemolysis ratio of DOX significantly. These results suggested that the novel anticancer nanomedicines based on DOX and amphiphilic Y-shaped copolymers were attractive candidates as tumor tissular and intracellular targeting drug delivery systems in vivo, with enhanced stability during circulation and accelerated drug release at the target sites.