Three-block Copolymers Research Articles

Generation of Sulfonated Lignin-Starch Polymer and Its Use As a Flocculant.

This paper reports the polymerization of tall oil lignin (TOL), starch, and 2-methyl-2-propene-1-sulfonic acid sodium salt (MPSA), a sulfonate-containing monomer, in a three-component system to generate flocculants for colloidal systems. By utilizing the advanced 1H, COSY, HSQC, HSQC-TOCSY, and HMBC NMR techniques, it was confirmed that the phenolic substructures of TOL and the anhydroglucose unit of starch were covalently polymerized by the monomer to generate the three-block copolymer. The molecular weight, radius of gyration, and shape factor of the copolymers were fundamentally correlated to the structure of lignin and starch, as well as the polymerization outcomes. The deposition behavior of the copolymer, studied by a quartz crystal microbalance with dissipation (QCM-D) analysis, revealed that the copolymer with a larger molecular weight (ALS-5) deposited more and generated more compact adlayer than the copolymer with a smaller molecular weight on a solid surface. Owing to its higher charge density, molecular weight, and extended coil-like structure, ALS-5 produced larger flocs with faster sedimentation in the colloidal systems, regardless of the extent of agitation and gravitational force. The results of this work provide a new approach to preparing a lignin-starch polymer, i.e., a sustainable biomacromolecule with excellent flocculation performance in colloidal systems.

Controlled temperature-mediated curcumin release from magneto-thermal nanocarriers to kill bone tumors

Systemic chemotherapy has lost its position to treat cancer over the past years mainly due to drug resistance, side effects, and limited survival ratio. Among a plethora of local drug delivery systems to solve this issue, the combinatorial strategy of chemo-hyperthermia has recently received attention. Herein we developed a magneto-thermal nanocarrier consisted of superparamagnetic iron oxide nanoparticles (SPIONs) coated by a blend formulation of a three-block copolymer Pluronic F127 and F68 on the oleic acid (OA) in which Curcumin as a natural and chemical anti-cancer agent was loaded. The subsequent nanocarrier SPION@OA-F127/F68-Cur was designed with a controlled gelation temperature of the shell, which could consequently control the release of curcumin. The release was systematically studied as a function of temperature and pH, via response surface methodology (RSM). The bone tumor killing efficacy of the released curcumin from the carrier in combination with the hyperthermia was studied on MG-63 osteosarcoma cells through Alamar blue assay, live-dead staining and apoptosis caspase 3/7 activation kit. It was found that the shrinkage of the F127/F68 layer stimulated by elevated temperature in an alternative magnetic field caused the curcumin release. Although the maximum release concentration and cell death took place at 45 °C, treatment at 41 °C was chosen as the optimum condition due to considerable cell apoptosis and lower side effects of mild hyperthermia. The cell metabolic activity results confirmed the synergistic effects of curcumin and hyperthermia in killing MG-63 osteosarcoma cells.

Fiber supercapacitor using epoxy-based gel polymer electrolyte with high ionic conductivity and mechanical flexibility

Recently, flexible energy storage devices have become an important issue for the smart textile market and flexible electric devices. Among them, fiber supercapacitors are one of the most promising candidates due to their light weight and mechanical flexibility. Traditional liquid electrolytes for fiber supercapacitors exhibit critical problems such as leakage when the device is deformed. On the other hand, solid electrolytes have a trade-off relationship between mechanical property for flexibility and ionic conductivity. Therefore, gel polymer electrolytes (GPEs) have attracted attention because of their sufficient ionic conductivity and high flexibility for maintaining their structure under bending, stretching, or twisting. However, liquid electrolytes in GPEs have a safety issue caused by narrow window voltage and flammability. Electrolytes with narrow window voltages could not provide the appropriate capacitance. To overcome this problem, ionic liquids that featured high electrochemical and thermal stability are used for GPEs. However, GPEs with ionic liquid have limited flexibility and ionic conductivity. In this work, we report a GPE comprising an ionic liquid and polyethylene oxide-abundant epoxy. The epoxy is synthesized from the crosslinking reaction between the amine with three-block copolymer and bisphenol A diglycidyl ether. The ionic conductivity of the fabricated GPE increased 2.0 × 10−3 S cm−1 at room temperature with increasing contents of 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide (EMImTFSI). Further, EMImTFSI gives an improvement of flexibility up to 107%. A fiber supercapacitor using developed GPE shows excellent electrochemical performance approaching using liquid electrolyte. In short, our result demonstrates that the GPE is a promising candidate for various applications involving multidirectional deformation such as fiber-type electric and flexible devices.

Visible Light-Driven Photocatalytic Activity and Kinetics of Fe-Doped TiO2 Prepared by a Three-Block Copolymer Templating Approach.

Fe-doped titania photocatalysts (with 1, 2.5, and 3.5 wt. % Fe nominal content), showing photocatalytic activity under visible light, were prepared by a soft-template assisted sol–gel approach in the presence of the triblock copolymer Pluronic P123. An undoped TiO2 photocatalyst was also prepared for comparison. The photocatalysts were characterized by means of X-ray powder Diffraction (XRPD), Quantitative Phase Analysis as obtained by Rietveld refinement, Diffuse Reflectance (DR) UV−Vis spectroscopy, N2 adsorption/desorption at −196 °C, electrophoretic mobility in water (ζ-potential), and X-ray photoelectron spectroscopy (XPS). The physico-chemical characterization showed that all the samples were 100% anatase phase and that iron was present both in the bulk and at the surface of the Fe-doped TiO2. Indeed, the band gap energy (Eg) decreases with the Fe content, with Tauc’s plot determined values ranging from 3.35 (undoped TiO2) to 2.70 eV (3.5 wt. % Fe). Notwithstanding the obtained Eg values, the photocatalytic activity results under visible light highlighted that the optimal Fe content was equal to 2.5 wt. % (Tauc’s plot determined Eg = 2.74 eV). With the optimized photocatalyst and in selected operating conditions, under visible light it was possible to achieve 90% AO7 discoloration together with a TOC removal of 40% after 180 min. The kinetic behavior of the photocatalyst was also analyzed. Moreover, the tests in the presence of three different scavengers revealed that the main reactive species are (positive) holes and superoxide species. Finally, the optimized photocatalyst was also able to degrade phenol under visible light.

Effect of alkali treatment and coupling agent on thermal and mechanical properties of Opuntia ficus-indica cladodes fibers reinforced HDPE composites

In this work, Opuntia ficus-indica (OFI) fibers were used as natural reinforcement to high-density polyethylene (HDPE) matrix to valorize unexploited Moroccan natural resources in composites applications. Composites specimens were prepared by combining extruder and injection molding processes using various fibers loadings (2.5, 5 and 10 wt%). OFI fibers were alkali treated to clean their surfaces from non-cellulosic compounds, and styrene–(ethylene–butene)–styrene three-block copolymer grafted with maleic anhydride (SEBS-g-MA) is used as coupling agent to graft maleic groups in the surface of matrix. Combined effects of both treatments on thermal and mechanical properties of prepared composites were investigated. Results showed that the alkali treatment proves to be more effective in improving interfacial adhesion between fibers and matrix, which positively influences the hardness and Young’s modulus properties of composites without SEBS-g-MA, while the addition of coupling agent increased composites plasticity and thermal stability owing to the chemical bond formation at fibers–matrix interface.

Preparation of N-doped nano-hollow capsule carbon nanocage as ORR catalyst in alkaline solution by PVP modified F127

In order to reduce the cost of oxygen reduction reaction (ORR) catalyst, a metal-free N-doped carbon nanocage as ORR catalysts is prepared by using Polyethylene oxide-polypropylene oxide-polyethylene oxide (PEO-PPO-PEO) three-block copolymer (F127), polyvinyl pyrrolidone (PVP) and Zn (OH)2 as a carbon source, nitrogen source and the morphology retaining agent, respectively, via a self-template method. The structure and microstructure of the N-doped carbon nanocage are characterized via physical characterization methods such as X-ray diffraction, Raman spectroscopy, scanning electron microscopy, transmission electron microscopy, Brunauer–Emmett–Teller method, and X-ray photoelectron spectroscopy. Electrochemical properties are evaluated in an O2-saturated alkaline solution. The obtained sample pyrolyzed at 800 °C with 10% content of PVP (C–N-800) presents nano-hollow carbon capsule with a diameter of 100 nm and shell thickness of 8 nm, and has the maximum surface area of 978 m2·g−1. In O2-saturated 0.1 M KOH solution, C–N-800's onset potential, limit current density, and half-wave potential, which are 0.87 V, 5.73 mA/cm2@0.45 V, and 0.77 V, respectively, are close to those of commercial 20% Pt/C catalysts. Meanwhile, its electrochemical performance only loss 11.75% after 5000 cycles, showing excellent ORR catalytic performance and stability. During self-assembly of F127, the added PVP participated into the process. Pyrolysis at 800 °C would result in the complete decomposition of F127 and PVP's lipophilic. So, the metal-free N-doped carbon nanocage was obtained and behaved excellent ORR catalytic activity and stability.

Study of curcumin partitioning in polymer-salt aqueous two phase systems

Curcumin is a polyphenolic compound derived from Curcuma longa, which has a wide range of pharmacological applications and it constitutes 2–5% of turmeric. An efficient separation method is needed for the purification of curcumin. A polymer-salt aqueous two-phase system (ATPS) has been developed for curcumin separation. The applied polymers include polyethylene glycol (PEG) 6000 and 2000, polypropylene glycol (PPG) 400 and a three-block copolymer of PEG-PPG (Pluronic L35), as well as magnesium sulfate and sodium sulfate. The phase behavior of the ATPSs and curcumin partitioning as well as the effect of cation, PEG molecular weight, polymer type and temperature (5, 15 and 25 °C) have been investigated. According to obtained results, Na2SO4 due to its high salting out effect is more suitable for the partitioning of curcumin. By increasing the molecular weight of the polymer, the hydrophobicity of the top phase and consequently, the partitioning increases. The partitioning of curcumin in the determined optimum PEG-salt (PEG6000-Na2SO4) and PPG-sodium sulfate ATPSs have been obtained 67 and 25, respectively. The lower volume ratio of the phases decreases the partitioning ability of PPG400-Na2SO4 ATPS. Pluronic L35-Na2SO4 was able to reach the complete partitioning of curcumin. As predicted by the calculated differences in solubility parameter applying group contribution method, this system has the most partition ability due to self-aggregation in aqueous solutions and by decreasing the temperature, the partition coefficient decreased, but it was still more than the other polymers.

Fabricating carbon nanocages as ORR catalysts in alkaline electrolyte from F127 self-assemble core-shell micelle

In order to reduce the cost of oxygen reduction reaction (ORR) catalyst in fuel cell, polyethylene oxide-polypropylene oxide-polyethylene oxide (PEO-PPO-PEO) three-block copolymer (F127) and Zn(OH)2 were used as carbon resource and morphology retaining agent to prepare porous nanocages for ORR catalyst in alkaline solution. Its composition and microstructure were characterized by X-ray diffraction Raman spectroscopy (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and Brunauer–Emmett–Teller (BET) method. Electrochemical properties were evaluated in O2 saturated alkaline solution. Results showed the sample obtained at 700 °C (C-700) was composed of porous carbon nanocages with diameter of 50 nm and shell thickness of 4 nm. C-700 had the maximum surface area (1011 m2 g−1) and the best ORR catalytic performance. The main reason is that polypropylene oxide (PPO) group at the lipophilic end begins to decompose at 500 °C, and the polyethylene oxide (PEO) group at the lipophilic end at 700 °C decomposes completely. In O2 saturated 0.1 M KOH solution, C-700's oneset potential, limit current density and half-wave potential, which were 0.89 V, 5.59 mA/cm2@0.45 V and 0.71 V, respectively, were close to that of commercial 20% Pt/C catalyst. It was noted that the oneset potential and half-wave potential of C-700 had barely change, and limit current density attenuated about 87.8% after 2000 CV cycle. The obtained catalyst behaved good catalytic activity and stability for ORR in alkaline solution and a potential application prospect in fuel cells.

Adhesive Compositions Based on Styrene–Isoprene–Styrene Three-Block Copolymer with Different Modifiers

The adhesive properties of styrene–isoprene–styrene (SIS) three-block copolymer of different brands modified with isoprene oligomer and Regalite R9100 depending on the adhesive composition and the adhesion-contact-formation temperature were studied. It was shown that oligoisoprene acts as a diluent, while Regalite R9100 modifies the system as a whole by decreasing the glass-transition temperature of the microphase of polystyrene blocks and contributes to the increase in the adhesive ability of the composition.

A directed self-assembly quasi-spider silk protein expressed in Pichia pastoris

ABSTRACTThe spider silk protein has distinctive physical, chemical, mechanical and biological properties. As a functional material, the application value of spider silk has increased in many fields. Consequently, considerable progress has been made in the expression of recombinant spider silk proteins through many host systems by gene engineering techniques. However, the mechanical properties of the silk fibre spun with the recombinant spider silk proteins are unsatisfactory because the recombinant spider silk proteins have too low of a molecular weight and do not have molecular orientation. This paper describes the construction and expression of a quasi-spider silk protein composed of spider silk protein and collagen-like peptides with the Pichia pastoris expression system. The quasi-spider silk protein is an ‘ABA-type’ triblock copolymer composed of triple helix-forming A blocks at both ends of the middle section. The triple helix-forming A blocks at both ends of the triblock copolymers consist of (Pro–Gly–Pro)n homopolymeric stretches, and the middle section of the molecule (B section) contains a spider silk protein that has been optimally designed. The supramolecular structure created by the three-block copolymers through directed self-assembly ensures that the artificial spider silk fibres will meet the requirement for molecular weight and definite molecular orientation, thus promoting the formation of silk fibres. The authors hope that this project will contribute to the study of materials science and biomedical engineering in regards to the huge potential of spider silk protein in these fields.

Ultrasound-Mediated Microbubble Destruction (UMMD) Facilitates the Delivery of CA19-9 Targeted and Paclitaxel Loaded mPEG-PLGA-PLL Nanoparticles in Pancreatic Cancer.

Pancreatic cancer, one of the most lethal human malignancies with dismal prognosis, is refractory to existing radio-chemotherapeutic treatment modalities. There is a critical unmet need to develop effective approaches, especially for targeted pancreatic cancer drug delivery. Targeted and drug-loaded nanoparticles (NPs) combined with ultrasound-mediated microbubble destruction (UMMD) have been shown to significantly increase the cellular uptake in vitro and drug retention in vivo, suggesting a promising strategy for cancer therapy. In this study, we synthesized pancreatic cancer-targeting organic NPs that were modified with anti CA19-9 antibody and encapsulated paclitaxol (PTX). The three-block copolymer methoxy polyethylene glycol-polylacticco-glycolic acid-polylysine (mPEG-PLGA-PLL) constituted the skeleton of the NPs. We speculated that the PTX-NPs-anti CA19-9 would circulate long-term in vivo, "actively target" pancreatic cancer cells, and sustainably release the loaded PTX while UMMD would "passively target" the irradiated tumor and effectively increase the permeability of cell membrane and capillary gaps. Our results demonstrated that the combination of PTX-NPs-anti CA19-9 with UMMD achieved a low IC50, significant cell cycle arrest, and cell apoptosis in vitro. In mouse pancreatic tumor xenografts, the combined application of PTX-NP-anti CA19-9 NPs with UMMD attained the highest tumor inhibition rate, promoted the pharmacokinetic profile by increasing AUC, t1/2, and mean residence time (MRT), and decreased clearance. Consequently, the survival of the tumor-bearing nude mice was prolonged without obvious toxicity. The dynamic change in cellular uptake, targeted real-time imaging, and the concentration of PTX in the plasma and tumor were all closely associated with the treatment efficacy both in vitro and in vivo. Our study suggests that PTX-NP-anti CA19-9 NPs combined with UMMD is a promising strategy for the treatment of pancreatic cancer.

Temperature-Switchable Agglomeration of Magnetic Particles Designed for Continuous Separation Processes in Biotechnology.

The purpose of this work was the synthesis and characterization of thermally switchable magnetic particles for use in biotechnological applications such as protein purification and enzymatic conversions. Reversible addition-fragmentation chain-transfer polymerization was employed to synthesize poly(N-isopropylacrylamide) brushes via a "graft-from" approach on the surface of magnetic microparticles. The resulting particles were characterized by infrared spectroscopy and thermogravimetric analysis and their temperature-dependent agglomeration behavior was assessed. The influence of several factors on particle agglomeration (pH, temperature, salt type, and particle concentration) was evaluated. The results showed that a low pH value (pH 3-4), a kosmotropic salt (ammonium sulfate), and a high particle concentration (4 g/L) resulted in improved agglomeration at elevated temperature (40 °C). Recycling of particles and reversibility of the temperature-switchable agglomeration were successfully demonstrated for ten heating-cooling cycles. Additionally, enhanced magnetic separation was observed for the modified particles. Ionic monomers were integrated into the polymer chain to create end-group functionalized particles as well as two- and three-block copolymer particles for protein binding. The adsorption of lactoferrin, bovine serum albumin, and lysozyme to these ion exchange particles was evaluated and showed a binding capacity of up to 135 mg/g. The dual-responsive particles combined magnetic and thermoresponsive properties for switchable agglomeration, easy separability, and efficient protein adsorption.

Dynamic mechanical thermal behavior analysis of doum fibers reinforced polypropylene composites

Doum palm fibers are an environmentally friendly reinforcement in polymer composites. Their mechanical properties and abundance allow its use as an innovative material composite. In this paper doum fibers were alkali treated to clean their surface and enhance polymer fibers interaction. Tensile and rheological properties were investigated to see the effect of fibers content on the composites properties. Also, comparative composites were processed to assure a good wettability between fibers and the polymer with the use of a coupling agent as styrene–(ethylene–butene)–styrene three-block copolymer grafted with maleic anhydride (SEBS-g-MA). Results shows that tensile properties was enhanced when fiber were added to the polymer and has enhanced more with the use of coupling agent. A gain of 70% and 77% in the Young’s modulus at 30wt.% fibers content for the binary and ternary composites, respectively. And a gain of 18% in tensile strength at 10wt.% fibers content for the ternary composites. Moreover, dynamic mechanical thermal analyses were carried out in order to compare the changes of the properties with frequency, fibers loading, temperature and compatibilizer.

Mechanical and thermal properties of polymer composite based on natural fibers: Moroccan hemp fibers/polypropylene

Moroccan hemp is a cellulosic fiber obtained from the north of Morocco. Their use as reinforcement in thermoplastic matrix composite requires a knowledge of their morphology and structure. In this paper the Moroccan hemp fiber was alkali treated to remove waxes and noncellulosic surface components. Fiber/matrix adhesion was assured by the use of a styrene-(ethylene-butene)-styrene three-block copolymer grafted with maleic anhydride (SEBS-g-MA) as a compatibilizer. Scanning electron microscopy (SEM), Fourier transforms infrared spectroscopy (FT-IR), Thermogravimetric analysis (TGA), tensile and torsional tests were carried out for hemp fibers polypropylene composite and the compatibilized composite at different fiber content. Thus, the binary composite PP/hemp fibers (Alk) and ternary system with maleic anhydride indicate clearly an improved adhesion of the fiber to the matrix as results of the good interaction at the interface. A gain of 50% on the Young’s modulus of PP/hemp 25wt.% without coupling agent and 74% on the PP/hemp 20wt.% composite with the coupling agent were found. Tensile strength curve shows a remarkable stabilization when the coupling agent was used.

Synthesis and characterization of mesoporous alumina and their performances for removing arsenic(V)

Mesoporous alumina, synthesized by combining the three-block copolymer Pluronic P123 as a template with aluminum hydroxide sol at room temperature followed by isolation and calcining, was employed as an effective adsorbent for removing arsenic(V) in the pH region of 2.5–7.0. Arsenic adsorption data of MA(400) are well fitted by the Langmuir isotherm model and the maximum adsorption capacity is 36.6mg/g at near neutral (pH=6.6±0.1). Calcination temperature plays an important role in determining the performance of MA(400), MA(600) and MA(800) for removing arsenic(V), and the corresponding As(V) removal is in the order of MA(400)>>MA(600)>MA(800). The kinetics data were well fitted to pseudo-second-order, which implies that “surface reaction” might be the rate limiting step. Thermodynamic parameters illustrated that As(V) adsorption over MA(400) was a spontaneous and endothermic process. Adsorption energy (2.61kJ/mol) is less than 8kJ/mol, indicating the adsorption process may be dominated by physisorption. The influence of coexisting anions on As(V) removal demonstrated that the removal was slightly affected by the presence of NO3- and SO42-, while the presence of SiO4-, PO43- and F- caused a sharp fall in removal effectiveness, especially when the ratio of coexisting anion concentration to As(V) was larger than 1.12.

Novel ternary block copolymerization of carbon dioxide with cyclohexene oxide and propylene oxide using zinc complex catalyst

Block copolymers of poly (propylene carbonate—cyclohexyl carbonate) (PPC-PCHC) were successfully synthesized by a one-pot method with the zinc complex catalyst (Zn2G). The IR and 1H-NMR and 13C-NMR spectra verified the introducing of PCHC segments in the copolymers. The GPC curves of the copolymers appeared only one peak and the DSC results showed three glass transition temperatures at 40 °C, 66 °C and 115 °C, indicating the three-block copolymer structure. TGA tests revealed that the thermal decomposition temperature of the synthesized block copolymers increased up to about 300 °C. The mechanical properties proved to be also enhanced greatly as evidenced by static and dynamic mechanical tests. The thermal and mechanical properties of the resultant block copolymers lay between those of PPC and PCHC, demonstrating the desired properties of a polymer can be achieved via block copolymerization.

Novel biodegradable, biomimetic and functionalised polymer scaffolds to prevent expansion of post-infarct left ventricular remodelling

Over the past decade, a large number of strategies and technologies have been developed to reduce heart failure progression. Among these, cardiac tissue engineering is one of the most promising. Aim of this study is to develop a 3D scaffold to treat cardiac failure. A new three-block copolymer, obtained from δ-valerolactone and polyoxyethylene, was synthesised under high vacuum without catalyst. Copolymer/gelatine blends were microfabricated to obtain a ECM-like geometry. Structures were studied under morphological, mechanical, degradation and biological aspects. To prevent left ventricular remodelling, constructs were biofunctionalises with molecularly imprinted nanoparticles towards the matrix metalloproteinase MMP-9. Results showed that materials are able to reproduce the ECM structure with high resolution, mechanical properties were in the order of MPa similar to those of the native myocardium and cell viability was verified. Nanoparticles showed the capability to rebind MMP-9 (specific rebinding 18.67) and to be permanently immobilised on the scaffold surface.

Spectroscopic Manifestation of Dye Pair Interactions at High Concentrations in Structurally Organized SiO2 Films

The concentration dependence of the spectra of ionic and neutral dyes encapsulated in mesoporous silicate films is studied. A mesoporous dyed SiO2 film was prepared by the sol-gel technology with the use of amphiphilic three-block copolymer Pluronic P123 as a surfactant. It is found that if the dye concentration exceeds the mesoporous one, the new spectral bands appear that are distinct from those of initial monomolecular predecessors. To explain the phenomenon, it is assumed and proved that the origin of new spectra is due to the formation of ionic pairs, excimers, and excitons with participation of dye molecules localized at the characteristic places of the mesoporous silicate film.

Properties of alkyl-phosphatidylcholine monolayers in the presence of surface-active three-block copolymers

The interaction of three-block copolymers (poloxamers) with dimyristoyl-phosphatidylcholine (DMPC) and dipalmitoylphosphatidylcholine (DPPC) was investigated in monolayer experiments. The poloxamers selected were BASF PLURONICS F-68, F-88 and F-98. All of them are water-soluble and possess two hydrophilic polyoxyethylene and one hydrophobic polyoxypropylene moiety but differ in molecular weight. These substances and their interfacial behaviour are interesting for the development of targeted drug delivery systems. Monolayer tensiometry revealed the degree of poloxamer penetration in PC monolayers and the changes in monolayer compression/expansion behaviour. Two different experimental protocols were used to determine the surface pressures ( π) and areas ( A) at “squeeze-out” (compression) and “insertion” (expansion) of the soluble component in the surface layer. The two protocols yielded differences in the “squeeze-out” and “insertion” parameters of the DMPC (DPPC)/Poloxamer systems. The differences disappear when comparing the product πA (2-D – “mechanical work”) for the various combinations of lipids and poloxamers. In all cases ( πA) out > ( πA) in. This approach reveals a possibility for adequate comparison of monolayer compression/expansion isotherms made by different experimental protocols.

Combined use of RGD-peptide modified PLGA and TGF-β1 gene transfected MSCs to improve cell biobehaviors in vitro

In order to improve the surface properties of PLGA polymer for a better material/cell interface to modulate the cells behaviors, we prepared a novel three-block copolymer, PLGA-[ASP-PEG], and immobilized an RGD-containing peptide, Gly-Arg-Gly-Asp-Ser-Pro-Cys (GRGDSPC) on the surface of it. Transforming growth factor-beta1 (TGF-beta1) was transfected into bone marrow stromal cells (MSCs) employed as seeded cells. Cell adhesion, spreading, proliferation and differentiation on this material were investigated. The results showed that the cell adhesive ratio on RGD-modified materials was higher than on un-modified materials (P<0.05). The extent of cell spreading was also wider on RGD-modified materials than on un-modified materials. Cell proliferation indices of transfected MSCs were increased as compared with the un-transfected MSCs (P<0.05). The ALP activities in the MSCs cultured with RGD-modified materials were higher than on un-modified materials after 14 days (P<0.05), and those in transfected MSCs were higher than in un-transfected MSCs (P<0.05). It was suggested that the combined use of RGD-modification and TGF-beta gene transfection could improve the interaction of biomaterial and cells.