Star Polymers

We describe here the first example of the synthesis of 4-arm star poly(acrylic acid) for use as a water-soluble drag reducing agent, by applying Cu(0)-mediated polymerization technique. High molecular weight 4-arm star poly(tert-butyl acrylate) (M n = 3.0-9.0 x 10 5 g mol -1 ) was first synthesized using 4,4'-oxybis(3,3-bis(2-bromopropionate)butane as an initiator and a simple Cu(0)/TREN catalyst system. Then, 4-arm star poly(tert-butyl acrylate) were subjected to hydrolysis using trifluoroacetic acid resulting in water-soluble 4-arm star poly(acrylic acid). Drag reduction test rig analysis showed 4-arm star poly(acrylic acid) to be effective as a drag reducing agent with drag reduction of 24.3 %. Moreover, 4-arm star poly(acrylic acid) exhibited superior mechanical stability when compared with a linear poly(acrylic acid) and commercially available drag reducing polymers; Praestol and poly(ethylene oxide). The linear poly(acrylic acid), Praestol and poly(ethylene oxide) all showed a large decrease in drag reduction of 8-12 % when cycled 30 times through the drag reduction test rig whilst, in contrast, 4-arm star poly(acrylic acid) demonstrated much higher mechanical stability.

Bioglass® was the first synthetic biomaterial that formed a chemical bond to bone. Although bioactive glass scaffolds can mimic bone's porous structure, they are brittle. Sol-gel derived hybrids could overcome this problem because their nanoscale co-networks of silica and organic polymer have the potential to provide unique physical properties and controlled homogenous biodegradation. Copolymers of methyl methacrylate (MMA) and 3-(trimethoxysilyl)propyl methacrylate (TMSPMA) has been used as an organic source for hybrids to take advantage of its self-hardening property. However, the effect of well-defined poly(MMA-co-TMSPMA) architecture in the hybrid system has not been investigated. Here, linear, randomly branched and star shaped methacrylate based copolymers were synthesized via reversible addition-fragmentation chain transfer (RAFT) polymerization method. These copolymers were then used to fabricate hybrids. The 3-D polymer structure had a significant effect on mechanical properties, providing higher strain to failure while maintaining a compressive strength similar to sol-gel glass. Star copolymer-SiO2 hybrids had a modulus of toughness 9.6 fold greater, and Young's modulus 4.5 fold lower than a sol-gel derived bioactive glass. During in vitro cell culture, MC3T3-E1 osteoblast precursor cells adhered on the surface regardless of the polymer structure. Introducing star polymers to inorganic-organic hybrids opens up possibilities for the fine-tuning physical properties of bone scaffold materials.

By employing rheological experiments, mode coupling theory, and computer simulations based on realistic coarse-grained models, we investigate the effects of small, hard colloids on the glassy states formed by large, soft colloids. Multiarm star polymers mimic hard and soft colloids by appropriately varying the number and size of their arms. The addition of hard colloids leads, depending on their concentration, to either melting of the soft glass or the emergence of two distinct glassy states. We explain our findings by depletion of the colloids adjacent to the stars, which leads to an arrested phase separation when the repulsive glass line meets the demixing binodal. The parameter-free agreement between experiment, theory, and simulations suggests the generic nature of our results and opens the route for designing soft-hard colloidal composites with tunable rheology.

In this paper, we focus on the synthesis and characterization of novel stable nanolayers made of star methacrylate polymers. The effect of nanolayer modification on its antibacterial properties was also studied. A covalent immobilization of star poly(N,N′-dimethylaminoethyl methacrylate) (PDMAEMA) to benzophenone functionalized glass or silicon supports was carried out via a “grafting to” approach using UV irradiation. To date, star polymer UV immobilization has never been used for this purpose. The thickness of the resulting nanolayers increased from 30 to 120 nm with the molar mass of the immobilized stars. The successful bonding of star PDMAEMA to the supports was confirmed by surface sensitive quantitative spectroscopic methods. Next, amino groups in the polymer layer were quaternized with bromoethane, and the influence of this modification on the antibacterial properties of the obtained materials was analyzed using a selected reference strain of bacteria. The resulting star nan...

We report a stepwise assembly strategy for the integration of metal-organic cages (MOCs) into block copolymers (BCPs). This approach creates "block co-polyMOC" (BCPMOC) materials whose microscopic structures and mechanical properties are readily tunable by adjusting the size and geometry of the MOCs and the composition of the BCPs. In the first assembly step, BCPs functionalized with a pyridyl ligand on the chain end form star-shaped polymers triggered by metal-coordination-induced MOC assembly. The type of MOC junction employed precisely determines the number of arms for the star polymer. In the second step, microphase separation of the BCP is induced, physically cross-linking the star polymers and producing the desired BCPMOC networks in the bulk or gel state. We demonstrate that large spherical M12L24 MOCs, small paddlewheel M2L4 MOCs, or a mixture of both can be incorporated into BCPMOCs to provide materials with tailored branch functionality, phase separation, microdo...

We describe here the first example of the synthesis of 4-arm star poly(acrylic acid) for use as a water-soluble drag reducing agent, by applying Cu(0)-mediated polymerization technique. High molecular weight 4-arm star poly(tert-butyl acrylate) (M n = 3.0-9.0 x 10 5 g mol-1) was first synthesized using 4,4'-oxybis(3,3-bis(2-bromopropionate)butane as an initiator and a simple Cu(0)/TREN catalyst system. Then, 4-arm star poly(tert-butyl acrylate) were subjected to hydrolysis using trifluoroacetic acid resulting in water-soluble 4-arm star poly(acrylic acid). Drag reduction test rig analysis showed 4-arm star poly(acrylic acid) to be effective as a drag reducing agent with drag reduction of 24.3 %. Moreover, 4-arm star poly(acrylic acid) exhibited superior mechanical stability when compared with a linear poly(acrylic acid) and commercially available drag reducing polymers; Praestol and poly(ethylene oxide). The linear poly(acrylic acid), Praestol and poly(ethylene oxide) all showed a large decrease in drag reduction of 8-12 % when cycled 30 times through the drag reduction test rig whilst, in contrast, 4-arm star poly(acrylic acid) demonstrated much higher mechanical stability.

Intrinsic antimicrobial thermoplastic A(BC) n copolymers (n ¼ 1, 2, 4), where A was poly(ethylene glycol) (PEG), BC was a random chain of methylmethacrylate (MMA), and alkyl-aminoethyl methacrylate (AAEMA), were synthesized and the antimicrobial activity and hemolyticity were evaluated on plaques obtained by casting as a function of the architecture, the N-substituent groups of the AAEMAs (methyl, ethyl, isopropyl, and tert-butyl groups) and the hydrophobic/charge density balance. Antimicrobial effectiveness and efficiency is controlled by the surface charge density and by the influence of N-alkyl groups on the surface morphology. Also interestingly, it is the absence of hemolitytic activity in all copolymers. In presence of Escherichia coli, the A(BC) 2 copolymer with 40% of N-methyl groups is the most efficient, killing 91% of the bacteria already after 1.5 h.

Intrinsic antimicrobial thermoplastic A(BC)n copolymers (n = 1, 2, 4), where A was poly(ethylene glycol) (PEG), BC was a random chain of methylmethacrylate (MMA), and alkyl-aminoethyl methacrylate (AAEMA), were synthesized and the antimicrobial activity and hemolyticity were evaluated on plaques obtained by casting as a function of the architecture, the N-substituent groups of the AAEMAs (methyl, ethyl, isopropyl, and tert-butyl groups) and the hydrophobic/charge density balance. Antimicrobial effectiveness and efficiency is controlled by the surface charge density and by the influence of N-alkyl groups on the surface morphology. Also interestingly, it is the absence of hemolitytic activity in all copolymers. In presence of Escherichia coli, the A(BC)2 copolymer with 40% of N-methyl groups is the most efficient, killing 91% of the bacteria already after 1.5 h.

By employing rheological experiments, mode coupling theory, and computer simulations based on realistic coarse-grained models, we investigate the effects of small, hard colloids on the glassy states formed by large, soft colloids. Multiarm star polymers mimic hard and soft colloids by appropriately varying the number and size of their arms. The addition of hard colloids leads, depending on their concentration, to either melting of the soft glass or the emergence of two distinct glassy states. We explain our findings by depletion of the colloids adjacent to the stars, which leads to an arrested phase separation when the repulsive glass line meets the demixing binodal. The parameter-free agreement between experiment, theory, and simulations suggests the generic nature of our results and opens the route for designing soft-hard colloidal composites with tunable rheology.

This article reports on a simple and straightforward preparation method of poly(amidoamine)s (PAAs) with heterodifunctional chain ends as well as of several up to now hardly obtainable PAA derivatives of biotechnological interest, such as for instance PAAs of controlled molecular weight and narrow polydispersity mono-functionalized at one end with an acrylamide group, PAAs with star-like molecular architecture, graft-PAA-protein conjugates, ''tadpole-like'' PAA conjugates with hydrophobic moieties able to self assemble into nanoparticles in aqueous media. The key step was to design suitable building blocks consisting of hetero-difunctional dimers (HDDs). In particular, the HDDs considered were the monoaddition products of bis-sec-amines and bisacrylamides expected to give PAAs of proven biomedical potential and were obtained as hydrochlorides or trifluoroacetates. In this form, they could be indefinitely kept dormant at 0-5 C in the dry state, whereas at room temperature and in aqueous media, they polymerized at pH > 7.5. The preparation of the abovecited PAA derivatives did not necessarily involve the preliminary synthesis of hetero-difunctional PAAs but was directly achieved by one-pot polymerization of HDDs in the presence of the substrates of interest. V

Well defined star copolymers have been prepared by copper-catalyzed atom transfer radical copolymerization of styrene and styryldiphenylphosphine starting from a modified Boltorn TM H30 multifunctional initiator. These polymers and an analogue obtained by debromination of the arm ends with nBu3SnH have been used in combination with [Rh(acac)(CO)2] for the homogeneous phase hydroformylation of 1-octene.

A series of cyclodextrin-based star polymers were synthesized using β-cyclodextrin (CD) as hydrophilic core, methyl methacrylate (MMA) and tert-butyl acrylate (tBA) as hydrophobic arms. Star polymers, either homopolymers or random/block copolymers, showed narrow molecular weight distributions. Grafting hydrophobic arms created CD-based nanoparticles (CD-NPs) in the size range (130-200nm) with narrow PdI <0.15 and slightly negative ζ-potential. Particle surface could be modified with chitosan to impart a positive surface charge. Colloidal stability of CD-NPs was a function of pH as revealed by the pH-titration curves. CD-NPs were used as carrier for the chemotherapeutic drug idarubicin (encapsulation efficiency, EE ∼40%) ensuring prolonged release profile (∼80% after 48h). For cell-based studies, coumarin-6 was encapsulated as a fluorescent marker (EE ∼75%). Uptake studies carried out on A549 and Caco-2 cell lines proved the uptake of coumarin-loaded NPs as a function of time and ...

In this article, we show that stimuli-induced microscopic transformations of self-assembled surfactant structures can be used to tune the macroscopic bulk and interfacial rheological properties. Previously, we had described the formation of micron-sized 12-hydroxystearic acid tubes having a temperaturetunable diameter in the bulk, and also adsorbing at the air-water interface. We report now a detailed study of the bulk and interfacial rheological properties of this solution of thermoresponsive tubes as a function of temperature. In the bulk, the structural modifications of tubes with temperature lead to sharp and non-monotonous changes of rheological behavior. As well, at the air-water interface, the interfacial layer is shifted several times from rigid-like to fluid-like as the temperature is increased, due to morphological changes of the adsorbed interfacial layer. The temperature-induced variations in the fatty acid supramolecular organization and the richness in structural transitions at this microscopic level lead to unique rheological responses in comparison with conventional surfactant systems. Also, this study provides new insights into the required packing conditions for the jamming of anisotropic soft objects and highlights the fact that this system becomes glassy under heating. Due to these unique macroscopic properties both in the bulk and at the interface, this simple system with stimuli-responsive viscoelasticity is of interest for their potential applications in pharmacology or cosmetic formulations.

Well defined star copolymers have been prepared by copper-catalyzed atom transfer radical copolymerization of styrene and styryldiphenylphosphine starting from a modified Boltorn TM H30 multifunctional initiator. These polymers and an analogue obtained by debromination of the arm ends with nBu3SnH have been used in combination with [Rh(acac)(CO)2] for the homogeneous phase hydroformylation of 1-octene.

a signifi cant challenge due to the lack of an effi cient biocompatible carrier that can deliver the necessary dose selectively into the cytoplasm of the diseased cells while sparing neighboring healthy ones. [ 5 ] Cationic lipids, [ 6 ] polymers, [ 7 ] and peptides [ 5d ] have been used to condense siRNA via electrostatic interaction forming ionic complexes that are internalized by endocytosis. However, these complexes are often trapped in the endosomal/lysosomal traffi cking pathway where the loaded siRNA cargo is degraded, which diminishes their therapeutic activity. [ 8 ] Amphiphilic pH-sensitive polymers have been used to complex siRNA forming "smart" particles that bypass the endosomal/lysosomal traffi cking pathway and deliver their cargo into the cytoplasm. [ 9 ] These polymers utilize their unique ability to switch from a hydrophilic stealthlike conformation at physiologic pH to a hydrophobic membrane-destabilizing one in response to acidic endosomal pH gradients to rupture the endosomal membrane and release the entrapped RNA cargo into the cytoplasm to produce the desired effect. [ 10 ] pH-sensitive membranedestabilizing polymers proved effective in delivering plasmid DNA, [ 11 ] antisense oligodeoxynucleotides, [ 12 ] siRNA, [ 13 ] and proteins [ 14 ] into the cytoplasm of multiple cells both in vitro [ 12 , 13 ] and in vivo. [ 15 ] These amphiphilic polymers typically incorporate ionizable acidic moieties, hydrophobic motifs, and cationic groups for sensing the change in environmental pH, disruption of the endosomal membrane, and complexation of the loaded DNA/RNA, respectively. [ 16 ] Earlier research showed that the membrane-destabilizing activity increases with the increase in polymer's molecular weight. [ 17 ] However, given their non-degradable composition, these polymers are poorly eliminated by urinary excretion in vivo, which increases the risk of their long term accumulation leading to non-specifi c toxicity. [ 17b ] In addition, increasing the number of hydrophobic motifs to enhance the membrane-disruptive activity dramatically reduced polymer's aqueous solubility and therapeutic utility. [ 17b ] Further, increasing the molar fraction of the cationic group to increase DNA/RNA loading and incorporation of targeting ligands (e.g., sugars, antibody fragments) has been shown to diminish the membrane-destabilizing activity of the formed particles and reduce the associated transfection capacity. [ 18 ] Development of Degradable, pH-Sensitive Star Vectors for Enhancing the Cytoplasmic Delivery of Nucleic Acids The report describes the synthesis of degradable, pH-sensitive, membranedestabilizing, star-shaped polymers where copolymers of hydrophobic hexyl methacrylate (HMA) and 2-(dimethylamino)ethyl methacrylate (DMAEMA) monomers are grafted from the secondary face of a beta-cyclodextrin (β-CD) core via acid-labile hydrazone linkages using atom transfer radical polymerization. The effect of the graft's molecular weight, HMA/DMAEMA molar ratio, and the fraction of DMAEMA converted to cationic N,N,N-trimethylaminoethyl methacrylate (TMAEMA) monomers on polymer's transfection capacity is systematically investigated. Results show that all star-shaped polymers condense anti-GAPDH silencing RNA (siRNA) into nanosized particles at + /-ratio ≤ 4:1. Star polymers with shorter (25kDa) P(HMA-co-DMAEMA-co-TMAEMA) grafts are more effi cient and less cytotoxic than carriers with longer (40kDa) grafts. The results show that increasing the ratio of hydrophobic HMA monomers in graft's composition higher than 50 mole% dramatically reduces polymer's aqueous solubility and abolishes their transfection capacity. Further, retention of DMAEMA monomers in graft's composition provide a buffering capacity that enhanced the endosomal escape and transfection capacity of the polymers. These systematic studies show that β-CD-P(HMA-co-DMAEMA-co-TMAEMA) 4.8 polymer with a 25 kDa average graft's molecular weight and a 50/25/25 ratio of HMA/DMAEMA/TMAEMA monomers is the most effi cient carrier in delivering the siRNA cargo into the cytoplasm of epithelial cancer cells.

A star polymer with a divinylbenzene core and statistically random methacrylate copolymer arms is synthesized with reversible addition−fragmentation−transfer method and fractionated with supercritical carbon dioxide and propane to obtain fractions with low molecular weight polydispersity. The phase behavior and density behavior are experimentally determined in supercritical propane for fractionated star polymers and the corresponding linear copolymer arms at temperatures to 423 K and pressures to 210 MPa. Experimental data are presented on the impact of the number of arms, the backbone composition of the lauryl and methyl methacrylate repeat units in the copolymer arms, and the divinylbenzene core on the polymer−propane solution behavior. The star polymer is significantly more soluble because of its unique structure compared with the solubility of the linear copolymer arms in propane. The resultant phase behavior for the two homopolymers and the copolymer arms in propane are modeled using the perturbed chain statistical associating fluid theory (PC-SAFT). Model calculations are not presented for the phase behavior of the star polymers in propane because the PC-SAFT approach is not applicable for star polymer structures.

The synthesis and characterization of two novel amphiphilic multiarm star polymers with linear polyethylene glycol (PEG) and poly(e-caprolactone) (PCL) arms and their use as toughening modifiers of epoxy anhydride thermosets are reported. The new star polymers were obtained by partial pegylation of a hyperbranched polyester and subsequent growth of PCL arms. The curing process was studied by calorimetry and thermomechanical analysis, demonstrating the accelerating effect and the influence on gelation of the hydroxyl terminal groups. The curing kinetics was analyzed by model-free and model-fitting methods. The final properties of the resulting materials were determined by thermal and mechanical tests. The addition of the star-like modifiers led only to notable improvement on impact strength in the material containing a 10% of the star with PCL and PEG arms, without compromising glass transition temperature and thermal stability. The morphology of the resulting materials depended on the structure of the toughness modifier used, as demonstrated by electron microscopy, but all modified thermosets obtained showed phase-separated morphologies with nanosized particles.

In this paper, we focus on the synthesis and characterization of novel stable nanolayers made of star methacrylate polymers. The effect of nanolayer modification on its antibacterial properties was also studied. A covalent immobilization of star poly(N,N′-dimethylaminoethyl methacrylate) (PDMAEMA) to benzophenone functionalized glass or silicon supports was carried out via a “grafting to” approach using UV irradiation. To date, star polymer UV immobilization has never been used for this purpose. The thickness of the resulting nanolayers increased from 30 to 120 nm with the molar mass of the immobilized stars. The successful bonding of star PDMAEMA to the supports was confirmed by surface sensitive quantitative spectroscopic methods. Next, amino groups in the polymer layer were quaternized with bromoethane, and the influence of this modification on the antibacterial properties of the obtained materials was analyzed using a selected reference strain of bacteria. The resulting star nan...

Tumor eradication has many challenges due to the difficulty of selectively delivering anticancer drugs to malignant cells avoiding contact with healthy tissues/organs. The improvement of antitumor efficacy and the reduction of systemic side effects can be achieved using drug loaded nanoparticles. In this study, poly (ethyl 2cyanoacrylate) nanoparticles (PECA-NPs) were prepared using an emulsion polymerization method and their potential for cancer treatment was investigated. The size, polydispersity index and zeta potential of prepared nanoparticles are about 80 nm, 0.08 and −39.7 mV, respectively. The stability test shows that the formulation is stable for 15 days, while an increase in particle size occurs after 30 days. TEM reveals the spherical morphology of nanoparticles; furthermore, FTIR and 1 H NMR analyses confirm the structure of PECA-NPs and the complete polymerization. The nanoparticles demonstrate an in vitro concentration-dependent cytotoxicity against human epithelial colorectal adenocarcinoma cell lines (Caco-2), as assessed by MTT assay. The anticancer activity of PECA-NPs was studied on 3D tumor spheroids models of hepatocellular carcinoma (HepG2) and kidney adenocarcinoma cells (A498) to better understand how the nanoparticles could interact with a complex structure such as a tumor. The results confirm the antitumor activity of PECA-NPs. Therefore, these systems can be considered good candidates in tumor treatment.

We report in this article the convenient synthesis of a class of hyperbranched poly(phenylacetylene)s (HBPPAs) containing various branching densities and different contents of pendant alkyne groups through one-pot chain-growth copolymerization of phenylacetylene (PA) with a diyne comonomer (1,3or 1,4-diethynylbenzene (DEB)). The polymerization was facilitated with the use of an in situ generated cationic diphosphine-ligated Pd(II) catalyst system. Serving effectively as difunctional cross-linker in the polymerization, the diyne comonomer first undergoes monoinsertion to render pendant alkyne groups, which can be further enchained to generate branching structures. A systematic investigation has been undertaken to study the effects of various polymerization parameters, including diyne/PA feed ratio, diyne type, temperature, and solvent, on the polymerization, polymer structure and topology. With either 1,3-or 1,4-DEB, a convenient tuning of polymer topology from linear to hyperbranched can be achieved by simply increasing diyne/PA feed ratio. Relative to 1,3-DEB, 1,4-DEB is more effective in rendering branching structures since the pendant alkyne groups suffer less steric effect from the polymer backbone and are thus more reactive. As to the solvent, a dichloromethane/methanol mixture (at vol. ratio of 13:3) was shown to better help the formation of branching structures than methanol alone as the resulting polymers can dissolve well in the former while precipitate in the latter. Because of their possession of the valuable pendant alkyne groups, these polymers have also been demonstrated for their use as building blocks in the synthesis of core−shell structured star polymers containing a HBPPA core and polystyrene arms through their Cu-catalyzed "click" reaction with an azide-ended polystyrene.

The purpose was to prepare triclosan-loaded polylactic acid nanoparticles containing b-cyclodextrin polymer shell, evaluate triclosan release from the particles using Franz diffusion cells and to study the stability of the particles in presence of a model protein, bovine serum albumin. The nanoparticles were prepared by a solvent displacement process. The nanoparticles were characterized by their size, encapsulation efficiency and morphology. They were of spherical shape with hydrodynamic diameter of about 100 or 200 nm depending on the polylactic acid used. Their high encapsulation efficiency (*90%) indicated that triclosan is easily incorporated into the nanoparticles. The nanoparticles displayed slow and sustained triclosan release patterns (diffusion coefficient about 10 -22 m 2 /s) and the b-cyclodextrin polymer coating was stable under simulated physiological conditions. All these data indicated that these novel core-shell nanoparticles might provide a promising carrier system for controlled release of triclosan and other hydrophobic drugs after systemic administration.

Lipase-catalyzed transesterifications were carried out without solvent and in mild conditions on permethylated b-cyclodextrins derivatives to obtain lipidylcyclodextrin, a new class of amphiphilic compounds with expected auto-assembly properties. Good conversion rate, of 6 I-(N-hydroxyethylsuccinamido)-6 I-deoxy-2 I , 3 I-di-O-methyl-hexakis (2 II-VII ,3 II-VII ,6 II-VII-triO methyl) cyclomaltoheptaose were obtained by using lipozyme as catalyst. Critical Aggregation Concentrations of these new derivatives of amphiphilic cyclodextrins (5.10-3 and 5.10-4 M) are in favor of an auto-association behavior. Finally, NMR experiments were carried out to evaluate the self-assembly of the compounds in water. The resulting supramolecular aggregates have potential to be used as nano-carriers for drug.

Globally ordered colloidal crystal lattices have broad utility in a wide range of optical and catalytic devices, for example, as photonic band gap materials. However, the self-assembly of stereospecific structures is often confounded by polymorphism. Small free-energy differences often characterize ensembles of different structures, making it difficult to produce a single morphology at will. Current techniques to handle this problem adopt one of two approaches: that of the " top-down " or " bottom-up " methodology, whereby structures are engineered starting from the largest or smallest relevant length scales, respectively. However, recently, a third approach for directing high fidelity assembly of colloidal crystals has been suggested which relies on the introduction of polymer cosolutes into the crystal phase [Mahynski, N.; Panagiotopoulos, A. Z.; Meng, D.; Kumar, S. K. Nat. Commun. 2014, 5, 4472]. By tuning the polymer's morphology to interact uniquely with the void symmetry of a single desired crystal, the entropy loss associated with polymer confinement has been shown to strongly bias the formation of that phase. However, previously, this approach has only been demonstrated in the limiting case of close-packed crystals. Here, we show how this approach may be generalized and extended to complex open crystals, illustrating the utility of this " structure-directing agent " paradigm in engineering the nanoscale structure of ordered colloidal materials. The high degree of transferability of this paradigm's basic principles between relatively simple crystals and more complex ones suggests that this represents a valuable addition to presently known self-assembly techniques.

A series of cyclodextrin-based star polymers were synthesized using -cyclodextrin (CD) as hydrophiliccore, methyl methacrylate (MMA) and tert-butyl acrylate (tBA) as hydrophobic arms. Star polymers, eitherhomopolymers or random/block copolymers, showed narrow molecular weight distributions. Graftinghydrophobic arms created CD-based nanoparticles (CD-NPs) in the size range (130–200 nm) with narrowPdI <0.15 and slightly negative -potential. Particle surface could be modified with chitosan to impart apositive surface charge. Colloidal stability of CD-NPs was a function of pH as revealed by the pH-titrationcurves. CD-NPs were used as carrier for the chemotherapeutic drug idarubicin (encapsulation efficiency,EE ∼40%) ensuring prolonged release profile (∼80% after 48 h). For cell-based studies, coumarin-6 wasencapsulated as a fluorescent marker (EE ∼75%). Uptake studies carried out on A549 and Caco-2 celllines proved the uptake of coumarin-loaded NPs as a function of time and preferential localization in thecytoplasm. Uptake kinetics revealed no saturation or plateau over 6 h. Chitosan-modified NPs showed sig-nificantly improved, concentration-dependent cellular uptake. Meanwhile, CD-NPs were non-cytotoxicon both cell lines over the concentration range (0.25–3 mg/ml) as studied by MTT and LDH assays. Inconclusion, CD star polymers can be considered a versatile platform for a new class of biocompatiblenanochemotherapy.