Local delivery of naringin in beta-cyclodextrin modified mesoporous bioactive glass promotes bone regeneration: from anti-inflammatory to synergistic osteogenesis and osteoclastogenesis.

The bone immune response dominated by macrophages plays an indispensable role in the osteogenesis of bone defects. Moreover, moderate polarization of macrophages against inflammatory M2 has been proved to promote osteogenesis. Therefore, the addition of anti-inflammatory agents to bioactive bone repair materials facilitates efficient bone regeneration by regulating the polarization of macrophages. Bioactive glass (BG) has been widely used for bone defect repair. However, BG alone cannot effectively inhibit the inflammatory response caused by in vivo biomaterial implantation, and finally cannot achieve satisfactory bone repair effect. Herein, the design of mesoporous bioactive glass nanoparticles (MBG) modified with ß-cyclodextrin (CD-MBG) is reported. Our research shows that the anti-inflammatory drug naringin (NG) is loaded into CD-MBG (NG@CD-MBG), which achieves a sustained release within 6 days. In vitro studies reveal that NG@CD-MBG promotes better transformation of macrophages to the M2 phenotype than MBG inhibiting macrophage inflammatory responses, while the induced local immune microenvironment synergistically facilitates osteogenesis and inhibits osteoclastogenesis. Furthermore, in vivo high expression of osteogenesis-related genes in the microenvironment stimulated by NG@CD-MBG significantly promotes new bone formation in the femoral defect model of rats. The results indicate that the combination of MBG and NG has a synergistic effect on immunomodulating osteogenesis and osteoclastogenesis, providing a novel idea for the development of bone biomaterials with favorable bone immunomodulatory properties.

Correlation between the topologically close-packed structure and the deformation behavior of metallic Cu64.5Zr35.5.

The topologically close-packed (TCP) structural characteristics in a model metallic glass (MG) of Cu64.5Zr35.5 have been investigated by molecular dynamics simulations. A group of structural indicators based on the largest standard cluster (LaSC) have been correlated with the non-affine displacement (D2) of atoms, so as to reveal the hidden correlation between local structures and deformation behavior of Cu64.5Zr35.5 during compression. It was found that the 15 types of Top-10 LaSCs are all TCP-like ones, among which the most numerous icosahedron (Z12 and 1-Z12) decreases in population sharply and moderately during respectively the elastic and yield region of compression; while in the fluid-flow region, the number of all Top-10 LaSCs tends to be almost constant. Low-D2 atoms prefer to link with each other; while medium-D2 atoms act as transition structures between backbone areas and deformation areas. Most interestingly, the deformation response of TCP-like atoms is not only determined by its nearest neighbor characteristics, but also depends on the linkage with other atoms. In addition, icosahedral atoms with a higher degree of medium range five-fold symmetry (MRFFS) are more resistant to the stress-induced deformation. Therefore, the TCP characteristics, including its nearest neighbor feature and the inter-connection between TCP LaSCs, are closely related with the deformation behavior of atoms, especially the MRFFS (up to 5 layers) of icosahedral atoms. These findings shed new light on the understanding of the relationship between microstructure and deformation response of MGs, which will promote the development of deformation theory of MGs.

Bioactive glass promotes the barrier functional behaviors of keratinocytes and improves the Re-epithelialization in wound healing in diabetic rats.

Upon skin injury, re-epithelialization must be triggered promptly to restore the integrity and barrier function of the epidermis. However, this process is often delayed or interrupted in chronic wounds like diabetic foot ulcers. Considering that BG particles can activate multiple genes in various cells, herein, we hypothesized that bioactive glass (BG) might be able to modulate the barrier functional behaviors of keratinocytes. By measuring the transepithelial electrical resistance (TEER) and the paracellular tracer flux, we found the 58S-BG extracts substantially enhanced the barrier function of keratinocyte monolayers. The BG extracts might exert such effects by promoting the keratinocyte differentiation and the formation of tight junctions, as evidenced by the increased expression of critical differentiation markers (K10 and involucrin) and TJ protein claudin-1, as well as the altered subcellular location of four major TJ proteins (claudin-1, occludin, JAM-A, and ZO-1). Besides, the cell scratch assay showed that BG extracts induced the collective migration of keratinocytes, though they did not accelerate the migration rate compared to the control. The in vivo study using a diabetic rat wound model demonstrated that the BG extracts accelerated the process of re-epithelialization, stimulated keratinocyte differentiation, and promoted the formation of tight junctions in the newly regenerated epidermis. Our findings revealed the crucial effects of BGs on keratinocytes and highlighted its potential application for chronic wound healing by restoring the barrier function of the wounded skin effectively.

Atomic structure evolutions and mechanisms of the crystallization pathway of liquid Al during rapid cooling.

The solidification of pure aluminum has been studied by a large-scale molecular dynamic simulation. The potential energy, position D, height H, and width W of the first peak and valley of PDF curves, and the local structures were investigated. It was found that the FCC-crystallization ability of pure Al is so strong that still local crystal regions exist in the amorphized solid. As the temperature decreases, besides the counter-intuitive increase in D p (D of the first peak), H p increases monotonically; W p, D v, and H v decrease monotonically; only W v first decreases and then increases. They all change critically when phase transition happens. After the nucleation, orientation-disordered HCP-regions, as the grain boundaries or defects of FCC crystals, rapidly transform into FCC structures, and then the surviving HCP-regions regularize into few parallel layers or orientation-disordered HCP-regions. If parallel layers result in dislocation pinning, structural evolution terminates; otherwise, it continues. These findings will have a positive impact on the development of the solidification and nucleation theory.

Different structural transitions of rapidly supercooled tantalum melt under pressure.

Molecular dynamics (MD) simulations have been performed to study the effects of pressure (P) on the crystallization of tantalum (Ta) under different pressures from [0, 100] GPa. The average potential energy of atoms in the system, the pair distribution function and largest standard cluster analysis (LSCA) have been employed to analyze the structure evolution. It was found that the solidified state at 100 K changes from the complex crystal (ß-Ta) through the body-centered cubic (bcc) crystal (α-Ta) to the hexagonal close-packed (hcp) crystal with increasing pressure. At P ≤ 3 GPa, the favorable state is ß-Ta, which is composed of Z12, Z14 and Z15 atoms, and crystallization starts at the same temperature of crystallization (Tc = 1897 K), while there is a stochastic relationship between the crystallinity and pressure. At P ∈ [3, 57.5] GPa, the melt is always crystallized into rather perfect α-Ta, and Tc is nearly linear to pressure. However, when P > 57.5 GPa, a quite perfect bcc crystal is first formed and then transforms to a hcp crystal via a solid-solid (bcc-hcp) phase transition. Moreover, if the new hcp atoms formed in the bcc stage are arranged in regular grains, the bcc-hcp transition would take a multiple-intermediate-state pathway else, a single-intermediate-state pathway is the possibilty. Additionaly, the parameter δs readily reflects the crystallinity of the ß-Ta, and smaller the value of δs, higher is the crystallinity of the ß-Ta. Finally, during the bcc-hcp transition under high pressure, the volume reduction is due to the rearrangement of atoms rather than the reduction in the atomic radius; a slight increase in the number of nearest neighboring pairs results in a significant increase of the system energy.

Dose-dependent modulation effects of bioactive glass particles on macrophages and diabetic wound healing.

Many pathophysiologic conditions can interrupt the normal wound healing process and lead to chronic wounds due to the arrest of macrophages in their inflammatory phenotype. Thus, strategies that promote the recovery of macrophage functions are of great benefit to heal chronic wounds. Bioactive glass (BG) dissolution has been recognized for its modulatory functions in macrophage polarization. However, further efforts are greatly needed to address how BG particles affect macrophage behaviors (such as proliferation, viability, migration and polarization) and wound healing through both direct contact and released ions. Our results showed that BG particles affect the proliferation/viability and polarization of macrophages in a dose-dependent manner. At a low concentration (20 µg mL-1), BG particles stimulated macrophage proliferation and promoted the M1-to-M2 phenotype switch; meanwhile, at a high concentration (100 µg mL-1), the particles showed significant cytotoxicity and prolonged the M1 phenotype of macrophages. The BG particles also exhibited strong chemotaxis to macrophages which appeared to be independent of their concentration. Dose-dependent regulation of macrophages and wound closure by BG particles were also observed in the healing of full-thickness wounds of diabetic rats. Our study suggests that the BG particle-mediated activities of macrophages are essential to wound healing, and these activities are greatly correlated with the amount of BG particles.

Topologically close-packed characteristic of amorphous tantalum.

The structural evolution of tantalum (Ta) during rapid cooling was investigated by molecular dynamics simulation, in terms of the system energy, the pair distribution function and the largest standard cluster analysis. It was found that the critical cooling rate for vitrification was about R ≥ 0.25 K ps-1, two orders lower than other metals (such as Au, Ag, Al, Zr and Zn) and that the meta-stable σ phase (ß-Ta) not only appears on the pathway from liquid to the stable body-centred cubic crystal, but is also easily obtained at room temperature as a long-lived metastable phase with some probability. The most interesting point is that the liquid, amorphous and ß-Ta phases share a nontrivial structural homology; the intrinsic topologically close-packed (TCP) structures in liquids are inherited and developed in different ways, resulting in amorphous or crystalline solids, respectively. With highly local packing fractions and geometrical incompatibility with the global close-packed (such as hcp, fcc and bcc) crystals, TCP structures inevitably result in structural heterogeneity and favour vitrification. As a superset of icosahedrons, TCP structures are ubiquitous in metallic melts, and just before the onset of crystallization reach their maximal number, which is much bigger in Ta than in other poor-GFA metals; so we argue that the strong forming ability of TCP local structures significantly enhances the glass forming ability of pure metals. These findings open up a new perspective that could have a profound impact on the research into metallic glasses.

Promoting in vivo early angiogenesis with sub-micrometer strontium-contained bioactive microspheres through modulating macrophage phenotypes.

Early vascularization capacity of biomaterials plays an essential role in efficient wound healing and tissue regeneration, especially in large tissue tension implanting position such as bone augmentation. Strontium-contained silica-based bioactive materials have shown the role of promoting angiogenesis by stimulating osteoblasts to secrete angiogenesis related cytokines. However, osteoblasts have little effect on early angiogenesis due to the inflammatory reaction of implantation site. Here, for the first time, we found that the monodispersed strontium-contained bioactive glasses microspheres (SrBGM) could significantly promote the early angiogenesis through regulating macrophage phenotypes. After being stimulated with SrBGM in vitro, RAW cells (macrophages) presented a trend towards to M2 phenotype and expressed high level of platelet-derived growth factor-BB (PDGF-BB). Moreover, the RAW conditioned medium of SrBGM significantly enhanced the angiogenic capacity of HUVECs. The in vivo early vascularization studies showed that significant new vessels were observed at the center of SrBGM-based scaffolds after implantation for 1 week in a bone defect model of rats, suggesting their enhanced early vascularization. Due to the efficient vascularization, the in vivo new bone formation was promoted significantly. Our study may provide a novel strategy to promote the early vascularization of biomaterials through modulating the microphage phenotypes, which has wide applications in various tissue regeneration and wound healing.

Sequentially-crosslinked biomimetic bioactive glass/gelatin methacryloyl composites hydrogels for bone regeneration.

In recent years, gelatin-based composites hydrogels have been intensively investigated because of their inherent bioactivity, biocompatibility and biodegradability. Herein, we fabricated photocrosslinkable biomimetic composites hydrogels from bioactive glass (BG) and gelatin methacryloyl (GelMA) by a sequential physical and chemical crosslinking (gelation + UV) approach. The results showed that the compressive modulus of composites hydrogels increased significantly through the sequential crosslinking approach. The addition of BG resulted in a significant increase in physiological stability and apatite-forming ability. In vitro data indicated that BG/GelMA composites hydrogels promoted cell attachment, proliferation and differentiation. Overall, the BG/GelMA composites hydrogels combined the advantages of good biocompatibility and bioactivity, and had potential applications in bone regeneration.

Neurotensin-loaded PLGA/CNC composite nanofiber membranes accelerate diabetic wound healing.

Diabetic foot ulcers (DFUs) are a threat to human health and can lead to amputation and even death. Recently neurotensin (NT), an inflammatory modulator in wound healing, was found to be beneficial for diabetic wound healing. As we demonstrated previously, polylactide-polyglycolide (PLGA) and cellulose nanocrystals (CNCs) (PLGA/CNC) nanofiber membranes show good cytocompatibility and facilitate fibroblast adhesion, spreading and proliferation. PLGA/CNC nanofiber membranes are novel materials that have not been used previously as NT carriers in diabetic wounds. This study aims to explore the therapeutic efficacy and possible mechanisms of NT-loaded PLGA/CNC nanofiber membranes in full-thickness skin wounds in spontaneously diabetic mice. The results showed that NT could be sustained released from NT-loaded PLGA/CNC composite nanofiber membranes for 2 weeks. NT-loaded PLGA/CNC composite nanofiber membranes induced more rapid healing than other control groups. After NT exposure, the histological scores of the epidermal and dermal regeneration and the ratios of the fibrotic area to the whole area were increased. NT-loaded PLGA/CNC composite nanofiber membranes also decreased the expressions of the inflammatory cytokines IL-1ß and IL-6. These results suggest that NT-loaded PLGA/CNC composite nanofiber membranes for sustained delivery of NT should effectively promote tissue regeneration for the treatment of DFUs.

The effect of pressure on the crystallization of rapidly supercooled zirconium melts.

Molecular dynamics simulations have been performed to explore the effect of pressure (P) on the crystallization of zirconium (Zr) under rapid cooling. The structural evolutions have been analysed in terms of the system energy, the pair distribution function and the largest standard cluster analysis. It was found that at the cooling rate of 1.0 × 1011 K s-1, which can crystallize Zr melts into hcp crystals via the bcc intermediate state under zero pressure, the critical pressure (Pc) for vitrification is about 28.75 GPa, and the larger the pressure, the higher the glass transition temperature Tg. At P < Pc the Ostwald's step rule is applied to Zr melts. Crystallization of rapidly super-cooled Zr melts under pressure always begins with the bcc phase and ends in the hcp crystal; the higher the pressure, the lower the onset temperature (Tc) of crystallization. Unlike the single-intermediate-state crystallization (SisC) under zero pressure, multiple-intermediate-state crystallization (MisC) is usually observed under pressure. Structural analysis reveals that if nucleation is essentially completed at the end of the first crystalline (bcc-dominated) stage, MisC will occur; otherwise, SisC occurs. The origin of such an observation is also discussed from the effect of pressure upon the thermodynamics and kinetics factors. These findings are useful for comprehensively understanding the solidification of metals under pressure.

Controlled Dual Delivery of Angiogenin and Curcumin by Electrospun Nanofibers for Skin Regeneration.

In this study, we successfully fabricated a novel drug and plasmid DNA (pDNA) dual delivery system by electrospinning the dispersion composed of polyethyleneimine-carboxymethyl chitosan/pDNA-angiogenin (ANG) nanoparticles, curcumin (Cur), poly (D, L-lactic-co-glycolic acid) (PLGA), and cellulose nanocrystals (CNCs). In vitro release studies showed that the bioactivity of Cur and ANG was preserved in the nanofibers, and a sequential release pattern was achieved in which nearly 90% of the Cur was released in ca. 6 days and the ANG release lasted up to about 20 days. In vitro cell culture results suggested that the composite nanofibers exhibit excellent biocompatibility. To evaluate the in vivo angiogenesis and anti-infection properties, the PLGA/CNC/Cur/pDNA-ANG composite nanofibers were transplanted into the infected full-thickness burn wounds. Biopsy specimens were harvested for histology, immunohistochemistry, immunofluorescence, real-time quantitative PCR, and Western blotting analyses. The results indicated that the PLGA/CNC/Cur/pDNA-ANG composite nanofibers not only prevented local infection but also promoted skin regeneration.

A combination of GDNF and hUCMSC transplantation loaded on SF/AGs composite scaffolds for spinal cord injury repair.

Spinal cord injury (SCI) is a severe trauma for which no effective treatment is currently available. In this study, a composited treatment system was prepared using a silk fibroin/alginates/glial cell line-derived neurotrophic factor (SF/AGs/GDNF) scaffold seeded with human umbilical cord mesenchymal stem cells (hUCMSCs) and the combined therapeutic effects of the composite scaffold to repair SCI rats were evaluated. The use of SF as a scaffold material could act as a biomimetic platform allowing neurons to properly accommodate and rebuild the target tissue. The SF/AGs/GDNF scaffold had the best sustained-release function and the AGs were the key determining factor in the controlled release of GDNF. After 8weeks of treatment, the hUCMSCs on SF/AGs/GDNF composite scaffolds could significantly enhance the scar expansion of spinal cord tissue and increased the number of surviving neurons. The combination of GDNF and hUCMSCs transplantation loaded on SF/AGs composite scaffolds exhibited better therapeutic and repair effects to the SCI of rats, compared with the SF/AGs group or GDNF alone on SF/AGs scaffolds. The composite scaffold, GDNF and stem cells could build a bioactive material to form the micro-environment of growth and repair of the neurons. These results may provide a theoretical basis and beneficial exploration for clinical treatment of SCI.

Structural evolutions and hereditary characteristics of icosahedral nano-clusters formed in Mg70Zn30 alloys during rapid solidification processes.

To investigate the structural evolution and hereditary mechanism of icosahedral nano-clusters formed during rapid solidification, a molecular dynamics (MD) simulation study has been performed for a system consisting of 107 atoms of liquid Mg70Zn30 alloy. Adopting Honeycutt-Anderson (HA) bond-type index method and cluster type index method (CTIM-3) to analyse the microstructures in the system it is found that for all the nano-clusters including 2~8 icosahedral clusters in the system, there are 62 kinds of geometrical structures, and those can be classified, by the configurations of the central atoms of basic clusters they contained, into four types: chain-like, triangle-tailed, quadrilateral-tailed and pyramidal-tailed. The evolution of icosahedral nano-clusters can be conducted by perfect heredity and replacement heredity, and the perfect heredity emerges when temperature is slightly less than Tm then increase rapidly and far exceeds the replacement heredity at Tg; while for the replacement heredity, there are three major modes: replaced by triangle (3-atoms), quadrangle (4-atoms) and pentagonal pyramid (6-atoms), rather than by single atom step by step during rapid solidification processes.

A novel crystallization pathway for SiGe alloy rapid cooling.

Understanding the structural evolution of covalent systems under rapid cooling is very important to establish a comprehensive solidification theory. Herein, we conducted molecular dynamics simulations to investigate the crystallization of silicon-germanium (SiGe) alloys. It was found that during crystallization, the saturation and orientation of covalent bonds are satisfied in order, resulting in three phase transitions. The saturation is satisfied during a continuous phase transition that occurs in the super-cooled liquid state. When the orientation was satisfied at the local scale, a novel state, the critical-nuclei crystalline (CNC) phase was obtained, where the local diamond structures increase in number with time and ultimately stabilize at an average size at the critical value. Finally with a coordinated rearrangement of atoms, the orientation is satisfied globally and a stable diamond crystal is produced. For SiGe alloys this CNC phase is universal and rather stable, and the stable temperature range has a certain relationship with the cooling rate and number fraction of atoms. This novel pathway is believed to be universal for such materials including carbon. The CNC state can explain the observation that diamond can be obtained without high pressure. These findings will significantly advance the understanding of the mechanism of phase transition, particularly for covalently bonded materials.

In Vitro Study of SnS2, BiOCl and SnS2-Incorporated BiOCl Inorganic Nanoparticles Used as Doxorubicin Carrier.

Inorganic nanoparticles have been widely used in biomedical field. In this paper, we try to study the use of three types of inorganic nanoparticles (i.e., SnS2, BiOCl and SnS2-incorporated BiOCl (SnS2/BiOCl)) as doxorubicin (DOX) carriers. Firstly, SnS2, BiOCl and SnS2/BiOCl were synthesised, then were characterized by TEM, nanoparticles size and zeta potential. Next the drug release and cell viability test were carried out. The cell viability test indicated that the drug carriers can effectively kill HeLa cells while maintaining low cytotoxicity against normal cells-fibroblasts. The results show the potential of SnS2/BiOCl nanoparticles for antitumor applications.

Synthesis, characterisation and preliminary investigation of the haemocompatibility of polyethyleneimine-grafted carboxymethyl chitosan for gene delivery.

The development of safe and efficient gene carriers is the key to the clinical success of gene therapy. In the present study, carboxymethyl chitosan (CMCS) was prepared by chitosan (CS) alkalisation and carboxymethylation reactions. Then polyethyleneimine (PEI) was grafted to the backbone of CMCS by an amidation reaction. The CMCS-PEI copolymer showed strong complexation capability with DNA to form nanoparticles, and achieved lower cytotoxicity and higher transfection efficiency compared with PEI (25 kDa) towards 293T and 3T3 cells. Moreover, the haemocompatibility of the CMCS-PEI copolymer was investigated through the aggregation, morphology and lysis of human red blood cells (RBCs), along with the impact on the clotting function with activated partial thromboplastin time (APTT), prothrombin time (PT) and thromboelastographic (TEG) assays. The results demonstrated that the CMCS-PEI copolymer with a concentration lower than 0.05 mg/mL had little impact on the aggregation, morphology or lysis of RBCs, or on blood coagulation. Therefore, the copolymer may be a strong alternative candidate as an effective and safe non-viral vector.

Synthesis, characterization of dextran hydrogels and their in vitro release of gentamycin sulphate.

PURPOSE: This study reports on the synthesis and characterization of biodegradable dextran-allyl isocyanate-ethylamine (Dex-AE)/polyethylene glycol-diacrylate (PEGDA) hydrogels for the controlled release of gentamycin sulphate (GS) and in vitro inhibition of organisms. METHODS: The Dex-AE precursor was prepared through a 2-step chemical modification and characterized by Fourier transform infrared spectroscopy (FTIR). RESULTS: Scanning electron microscopy (SEM) results revealed that an increase in Dex-AE content led to an initial decrease in pore size of the Dex-AE/PEGDA hydrogels, but a further increase in Dex-AE content resulted in a slightly increase of pore size. The swelling data indicated that the swelling ratio depended on the precursor feed ratio. GS was incorporated into the hydrogels through 2 different methods, i.e., immersed and crosslinked. The crosslinked GS-Dex-AE/PEGDA hydorgels exhibited stronger antimicrobial activities against Escherichia coli, Staphylococcus aureus, and Pseudomonas aeruginosa. Finally, the viscoelastic properties of crosslinked GS-Dex-AE/PEGDA hydorgels were investigated.

Preparation and properties of PLGA nanofiber membranes reinforced with cellulose nanocrystals.

Although extensively used in the fields of drug-carrier and tissue engineering, the biocompatibility and mechanical properties of polylactide-polyglycolide (PLGA) nanofiber membranes still limit their applications. The objective of this study was to improve their utility by introducing cellulose nanocrystals (CNCs) into PLGA nanofiber membranes. PLGA and PLGA/CNC composite nanofiber membranes were prepared via electrospinning, and the morphology and thermodynamic and mechanical properties of these nanofiber membranes were characterized by scanning electron microscopy (SEM), thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), and dynamic mechanical analysis (DMA). The cytocompatibility and cellular responses of the nanofiber membranes were also studied by WST-1 assay, SEM, and confocal laser scanning microscopy (CLSM). Incorporation of CNCs (1, 3, 5, and 7 wt.%) increased the average fiber diameter of the prepared nanofiber membranes from 100 nm (neat PLGA) to ∼400 nm (PLGA/7 wt.% CNC) and improved the thermal stability of the nanofiber membranes. Among the PLGA/CNC composite nanofiber membranes, those loaded with 7 wt.% CNC nanofiber membranes had the best mechanical properties, which were similar to those of human skin. Cell culture results showed that the PLGA/CNC composite nanofiber membranes had better cytocompatibility and facilitated fibroblast adhesion, spreading, and proliferation compared with neat PLGA nanofiber membranes. These preliminary results suggest that PLGA/CNC composite nanofiber membranes are promising new materials for the field of skin tissue engineering.

Controlled release and targeted delivery to cancer cells of doxorubicin from polysaccharide-functionalised single-walled carbon nanotubes.

Carboxyl single-walled carbon nanotubes (SWNTs) were used to construct an innovative drug delivery system by modification with chitosan (CHI) to enhance water solubility and biocompatibility. Hyaluronan (HA), as the target ligand for CD44, was bound to the CHI layer to selectively kill cancer cells. To achieve a new treatment strategy for cancer, the drug delivery system was loaded with the anticancer drug doxorubicin hydrochloride (DOX). The data showed that the system loaded with DOX with zeta potentials of 8.52 ± 0.12 mV at pH 7.4 and 12.53 ± 0.23 mV at pH 5.5 had high drug-loading efficiency, reaching 107.73 ± 0.67%. It also exhibited sustained and controlled drug-release, depending on pH; it released less than 10% at pH 7.4 but nearly 85% at pH 5.5 after 72 h. Cell viability results indicated that the drug delivery system effectively killed HeLa cells while it had lower cytotoxicity against fibroblasts. Combined histological examinations and blood property analyses demonstrated that it did not cause severe damage to vital organs in SD rats. Thus, this drug delivery system may provide a high therapeutic efficacy for cancer, while minimising adverse side effects.