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As a compound from marine fungi, (+)-terrein showed significant anticancer activity. In this study, (+)-terrein was extracted from the marine-derived fungus and showed significant cytotoxicity against cancer cells, especially in A549 cells. To enhance its anticancer effects, redox-responsive nanocarriers based on folic acid-chitosan decorating the mesoporous silica nanoparticles were designed to control (+)-terrein target delivery into cancer cells. (+)-Terrein was loaded in the holes, and folic acid-chitosan worked as a gatekeeper by disulfide linkage controlling (+)-terrein release in the tumor microenvironment. The (+)-terrein drug delivery systems exhibited cytotoxicity toward A549 cells through induction of apoptosis. The apoptosis effect was confirmed by the increase in the expression of cleaved caspase-3, caspase-9, and PARP. Taken together, this work evaluates for the first time the (+)-terrein delivery system and provides a promising nanomedicine platform for (+)-terrein.

Efficient delivery of chemotherapeutic agents into tumor cells and reversal of chemoresistance are crucially important to enhance cancer therapy. We fabricated pH/redox dual responsive nanocarriers based on cell penetrating peptides (TAT) functionalized TPGS (cTAT-TPGS) and polypeptide (PEG-b-poly(aspartic-lipoic acid), PPAL) to reduce the permanent drug release and overcome multidrug resistance. TAT was used to functionalize TPGS and shielded by pH-responsive fatty acids, and polypeptides with lipoic acid side chains (PPAL) were synthesized. Reversibly crosslinked hybrid micelles (RCMs) were fabricated based on cTAT-TPGS and PPAL. RCMs nanocarriers exhibited acid-responsive charge reversal and redox-responsive drug release. The in vitro results showed that the RCMs could be efficiently internalized by the MCF-7/ADR cells in an acidic microenvironment and inhibited the DOX efflux, causing a higher cytotoxicity than non-crosslinked nanocarriers. Furthermore, the dual-responsive structure effectively prolonged the circulation time of RCM nanocarriers and achieved a high level of accumulation in cancer cells in vivo, leading to much more effective inhibition of tumor growth. The DOX-loaded RCMs also showed excellent biosafety, especially for the myocardium tissue. This novel strategy provided an effective platform for drug target delivery and reversal of MDR.

The efficient triggering of prodrug release has become a challengeable task for stimuli-responsive nanomedicine utilized in cancer therapy due to the subtle differences between normal and tumor tissues and heterogeneity. In this work, a dual ROS-responsive nanocarriers with the ability to self-regulate the ROS level was constructed, which could gradually respond to the endogenous ROS to achieve effective, hierarchical and specific drug release in cancer cells. In brief, DOX was conjugated with MSNs via thioketal bonds and loaded with β-Lapachone. TPP modified chitosan was then coated to fabricate nanocarriers for mitochondria-specific delivery. The resultant nanocarriers respond to the endogenous ROS and release Lap specifically in cancer cells. Subsequently, the released Lap self-regulated the ROS level, resulting in the specific DOX release and mitochondrial damage in situ, enhancing synergistic oxidation-chemotherapy. The tumor inhibition Ratio was achieved to 78.49%. The multi-functional platform provides a novel remote drug delivery system in vivo.

Hepatocellular carcinoma (HCC) is one of the major cancers with high mortality rate. Traditional drugs used in clinic are usually limited by the drug resistance and side effect and novel agents are still needed. Macrolide brefeldin A (BFA) is a well-known lead compound in cancer chemotherapy, however, with poor solubility and instability. In this study, to overcome these disadvantages, BFA was encapsulated in mixed nanomicelles based on TPGS and F127 copolymers (M-BFA). M-BFA was conferred high solubility, colloidal stability, and capability of sustained release of intact BFA. In vitro, M-BFA markedly inhibited the proliferation, induced G0/G1 phase arrest, and caspase-dependent apoptosis in human liver carcinoma HepG2 cells. Moreover, M-BFA also induced autophagic cell death via Akt/mTOR and ERK pathways. In HepG2 tumor-bearing xenograft mice, indocyanine green (ICG) as a fluorescent probe loaded in M-BFA distributed to the tumor tissue rapidly, prolonged the blood circulation, and improved the tumor accumulation capacity. More importantly, M-BFA (10 mg/kg) dramatically delayed the tumor progression and induced extensive necrosis of the tumor tissues. Taken together, the present work suggests that M-BFA has promising potential in HCC therapy.

PDT is a well-established therapeutic modality for many types of cancer. Photoluminescent cyclometalated iridium(III) complexes are one of the most commonly used classes of organometallic compounds with potential beneficial applications in bioimaging and as promising anticancer agents. In the present study, three new cyclometalated iridium(III) complexes (Ir1–Ir3) containing guanidinium ligands were found to exert excellent cytotoxic effects on different types of cancer cells upon light irradiation at 425 nm. Notably, Ir1 conferred almost no dark toxicity (IC50 > 100 μM) to HepG2 cells, but the value decreased by 387-fold to 0.36 μM following 10 min of light irradiation (425 nm). Further mechanistic investigation revealed that complex Ir1 could induce apoptosis via the activation of reactive oxygen species (ROS)-mediated mitochondrial signaling pathways in the presence or absence of light irradiation. In vivo studies demonstrated that Ir1 significantly inhibited tumor growth in HepG2 xenograft-bearing mice under light irradiation at 425 nm. Taken together, these findings indicate that designing PDT-based Ir(III) complexes may hold a great deal of promise for anticancer drug development.

Hierarchical responsive nanocarriers have received much attention for targeted delivery of chemotherapeutics. In this study, we designed pH and redox dual-stage responsive nanocarriers in the different delivery stages for co-delivery phosphorylated curcumin (p-Cur) with doxorubicin (Dox). The MSNs nanocarriers were functionalized via specific cleavable PEGylation and hydrogel coating crosslinked by disulfide bonds: MSNs as core load Dox; p-Cur encapsulated in hydrogel coating. In blood circulation, PEGylation endow the nanocarriers with long time during blood circulation; while in tumor tissue, PEG shells could be cleaved due to the pH-sensitive bond and expose the cationic hydrogel coating to improve cell uptake; while inside tumor cells, hydrogel coating could be cleaved due to the GSH and release the drugs. The results showed that the dual-responsive shells endowed the nanocarriers with tumor extracellular pH-triggered cell uptake and specific cancer cell target release. The synergistic effects of the p-Cur and Dox enhanced cellular apoptosis in Hela cells.

In this study, the electroactive hybrid gels with controllable sol-gel process were fabricated based on the water soluble polyaniline complex and water soluble silica precursor. β-cyclodextrin grafted on chitosan (CSCD) acted as a template, a new route for the synthesis of water soluble polyaniline complex (PA@CSCD) was designed by in-situ polymerization. Then, the hybrid silica gels without severe shrinkage were prepared by mixing PA@CSCD complex with water soluble precursor (tetrakis(2-hydroxyethyl)orthosilicates, THEOS). By dynamic rheological measurements, it was found that PA@CSCD complex could trigger and accelerate the sol-gel transition of the silica precursor. The gelation time could be largely shortened with the increase of PA@CSCD complex amount. By SEM observation, the PA@CSCD complex could be well compatible with the silica matrix. Moreover, the hybrid gels showed the good redox electroactivity, which could be successfully applied in a HRP-based biosensor.

We developed a high-efficiency nucleus-targeted co-delivery vector that delivers genes and drugs directly into the nucleus of cancer cells. The system is based on grafted poly-(N-3-carbobenzyloxy-lysine) (CPCL) with transactivator of transcription (TAT)- chitosan on the surface. It is designed to perform highly efficient nucleus- targeted gene and drug co-delivery. Confocal laser scanning microscopy (CLSM) revealed that more TAT-CPCL entered the nucleus than does CPCL alone. The TAT-modified vector serves as a gene and drug co-delivery mechanism to achieve high gene transfection efficiency, high apoptosis and low viability in HeLa cells. TAT-CPCL may become a vector for cancer gene treatment and a template for designing better co-deliver systems.

In this work, we developed a drug-conjugated nanocarrier with "zero premature release" property for actively targeted drug delivery. The pH and redox dual-responsive nanocarrier was fabricated based on hyaluronic acid (HA) modified the mesoporous silica nanoparticles (MSNs). Doxorubicin (DOX) was conjugated to MSNs via hydrazone bonds, which can be cleaved in tumor tissue (acidic conditions). To improve specific cellular uptake and stability of nanocarriers, HA was equipped with an outer shell on the nanoparticle surface via a disulfide crosslinker. Stimulus-induced release of the DOX was studied in the different pH and GSH, which showed the embedded DOX can be controlled release from MSN channels. The dual-triggered drug release system provides an efficient targeted drug delivery system into the cytosol of cancer cells. The results of flow cytometry and confocal laser scanning microscopy (CLSM) showed that the HA-functionalized DOX-conjugated nanoparticles presented much better cellular uptake and higher cytotoxicity to tumor cells. This drug delivery system has great potential for tumor-trigged drug release for cancer therapy.

Stimuli-responsive nanocarriers for anticancer drug and gene co-delivery are promising strategy in cancer therapy. The ultimate goal is to deliver high local concentration of therapeutic agents with no premature release and result in synergistic effects for combination therapies. In this work, we developed a redox stimuli-responsive and synergistic co-delivery system for anticancer drug DOX and p53 gene for potential cancer therapy. A dendronized chitosan derivative (CP) as a "gatekeeper" to control release the drug was used to modify MSNs via a disulfide linker and improve the gene transfection efficiency. Stimulus-induced release of the DOX was studied in the presence of glutathione (GSH), which showed that polymer shell was shed and accelerated the release of embedded drugs inside the tumor cells under a GSH-rich environment. The obtained nanoparticles showed good gene delivery ability in vitro by inducing an obvious increase in p53 protein expression in Hela cells. Apoptosis analysis confirmed that DOX and p53 could be co-delivered to the Hela cells by MSN-SS-CP nanocarriers and induced significant cell apoptosis. These results demonstrated that the dual delivery system resulted in synergistic effects and lead to an effective cancer cell apoptosis, which may be promising for cancer therapeutic application.

Inflammation plays critical roles in the pathogenic mechanisms of several neurodegenerative disorders including Alzheimer’s disease (AD). Previous study revealed that CoQ10 augmented cellular antioxidant defense capacity, thereby protecting PC12 cells from oxidative neurotoxicity. However, the mechanism by which CoQ10 inhibits inflammation remains unknown. In this study, we aim to examine the effects of CoQ10 on Aβ25–35–induced inflammatory in PC12 cells and the underlying molecular mechanism of its neuroprotective action. CoQ10 suppressed the protein expression of COX-2 and the level of PGE2 in Aβ25–35–injured PC12 cells. These inhibitions appeared to correlate with the suppression of NF–κB activation by CoQ10, as pretreating PC12 cells with CoQ10 blocked the translocation of NF–κB into the nuclear compartment and degradation of the inhibitory subunit IκB. Overall, these results implied that CoQ10 attenuated neuroinflammatory responses through the inactivation of NF–κB dependent inflammatory pathways in Aβ25–35–induced PC12 cells. Therefore, CoQ10 may have therapeutic potential for neurodegenerative diseases by inhibiting pro-inflammatory mediators production.

Amphiphilic diblock poly(e-caprolactone)-b-glycopolypeptides (PCL–SS–GPPs) bearing disulfide bonds were synthesized from a clickable poly(e-caprolactone)–SS–poly(2-azidoethyl-L-glutamate) diblock copolymer. Galactosyl and lactosyl sugar units as targeting ligands were conjugated to the polypeptide blocks via an efficient click reaction. The chemical structures of PCL–SS–GPPs were characterized by Fourier transform infrared spectroscopy and nuclear magnetic resonance analysis. Owing to their amphiphilic nature, these copolymers could self-assemble into spherical nano-sized micelles in an aqueous medium, as confirmed by fluorometry, transmission electron microscopy, and dynamic light scattering. The hydrophobic anticancer drug doxorubicin (DOX) and superparamagnetic iron oxide (SPIO) nanoparticles (NPs), as the magnetic resonance imaging (MRI) contrast agent, were simultaneously encapsulated in the hydrophobic core of the micelles via dialysis. The release profiles of encapsulated DOX from the SPIO/DOX-loaded PCL–SS–GPPs micelles were shown to be rapid in the presence of 10 mM glutathione (GSH) within 24 h, whereas in the absence of GSH, there was less than 35% DOX released from the PCL–SS–GPPs micelles in 24 h. Inverted fluorescence microscopy revealed the specific interaction between the sugars units on the PCL–SS–GPPs surface with the FITC-lectin. MTT assay demonstrated that the blank PCL–SS–GPPs micelles were nontoxic to the HepG2 cells, even for concentrations up to 500 μg mL−1, whereas the free DOX and DOX-loaded PCL–SS–GPPs micelles showed significant cytotoxicity against the HepG2 cells. The fluorescence images and flow cytometry tests revealed that DOX could be efficiently transported into HepG2 tumor cells by PCL–SS–GPPs micelles. The PCL–SS–GPPs micelles loaded with superparamagnetic iron oxide (SPIO) nanoparticles enabled excellent MRI contrast enhancement, thus confirming their effectiveness for MR imaging.

D-α-Tocopherol polyethylene glycol succinate (TPGS) has been widely applied in drug delivery systems (DDS) to reverse tumor multidrug resistance (MDR) caused by overexpression of P-glycoprotein (P-gp). However its capability of inhibiting overexpression of P-gp is still limited due to poor penetration and premature drug release. Herein, the dual-targeted CMs based on charge reversal cell penetration peptide (cTAT) functionalized TPGS (cTAT-TPGS) and folic acid functionalized polypeptide (Folic acid-PEG-b-poly(Aspartic-Lipoic acid), FA-PPAL) were designed to reverse chemoresistance and improve chemotherapeutic efficacy. TAT was shielded by fatty acids and polypeptide introduced disulfide bonds. The CMs could keep stability with minimal drug leakage in blood circulation, whereas charge of TAT transform positive to improve the penetration and rapid dissociation of CMs to control drug release in low acidic and reductive environment of cancer cells. Furthermore, DOX achieved high accumulation in drug resistant cancer cells and directly released inside nucleus, leading to anti-MDR abilities and effective inhibition of tumor growth. Moreover, the DOX-loaded CMs showed excellent biosafety, especially for the myocardium tissue. Overall, this novel strategy provided an effective platform for drug target delivery and reversal of MDR.

Stimuli-responsive nanocarriers for anticancer drug and gene co-delivery are a promising strategy in cancer therapy due to their combination of chemotherapy and gene therapy. In this work, we developed a facile and effective method to fabricate stimuli-responsive nanocarriers for anticancer drug and gene co-delivery based on complexes of polyethylenimine (PEI) with an adenosine triphosphate (ATP) responsive aptamer duplex (ARAD). No chemical reactions or complex modifications were used in the construction processes. In this system, Doxorubicin-loaded aptamer duplex and plasmid DNA (p53) can be bound by PEI by electronic interactions to form stable complexes which effectively protect the aptamer and p53 from DNase degradation. The intercalated Dox can be released on-demand by a structural change in the aptamer duplex in an ATP-rich environment. The morphology and average size of the nanocarriers were characterized by zeta potential and transmission electron microscopy (TEM). The nanocarriers exhibit lower cell toxicity in HeLa cell lines relative to PEI. RT-PCR and Western blot analysis confirmed that p53 could be effectively delivered and expressed in HeLa cells by PEI/ARAD/p53 complexes. Moreover, the apoptosis percentage of HeLa cells treated with PEI/ARAD/Dox/p53 complex increased to 40.8%, compared to 24.7% for PEI/ARAD/Dox complex and 11.5% for PEI/ARAD/p53, respectively. The result demonstrated that the combinatorial delivery of Dox and p53 by nanocarriers could induce synergistic actions and lead to effective cancer cell apoptosis.

In this work, novel biodegradable cationic micelles were prepared based on poly-(N-e-carbobenzyloxy-L-lysine) (PZLL) and chitosan (CS) by click reaction, and applied for co-delivery of doxorubicin (DOX) and p53 plasmid. The structure of the copolymer was characterized by 1H NMR and FTIR. The loading amount of DOX in the micelles was 12.8%. Fluorescence spectra confirmed that DOX interacted via π–π stacking with micelles when DOX was encapsulated into the micelles. In particular, its complexation with plasmid DNA was investigated using agarose gel electrophoresis, flow cytometry, zeta potential, and particle size analyses as well as transmission electron microscopy observations. The results showed that the copolymers have a strong pDNA condensation ability and provide protection of pDNA against deoxyribonuclease I degradation. CS-g-PZLL/DOX/p53 nanoparticles showed good gene transfection efficiency in vitro. Fluorescence images and flow cytometry tests revealed that p53 and DOX could be efficiently transported into Hela tumor cells simultaneously, and the optimum N/P ratio for p53 transfection was 20/1. For co-delivery analysis, the obtained CS-g-PZLL/DOX/p53 complexes showed a better inhibitory effect on Hela tumor cells than DOX or p53 used singly.

The nucleus is one of the most important cellular organelles, where gene encode and transcribe at that location. However, nucleus-targeting gene delivery are rare been reported. It is important to develop a high-efficiency nucleus-targeting gene vector that can deliver targeted gene into nucleus directly for destroy of cancer cells. Here, special nucleus-targeting and size changeable deliver system based on TAT-SS-PAMAM-D3 with TAT functional on the surface and disulfide linked between D2 and D3 is designed to perform highly efficient nucleus-targeting gene delivery for effective cancer cell killing in vitro. CLSM observations reveal that more TAT-SS-PAMAM-D3 are enter into the nucleus when compare to SS-PAMAM-D3. The TAT modified vector can also act as gene deliver to reach high gene transfection efficiencies, high apoptosis and low viability in HeLa cells. This TAT functionalized and disulfide linking in the carrier may become a prospective vector for cancer gene treatment and also offered a different strategy for designing a better gene delivery system.

The codelivery of drug and gene is a promising method for cancer treatment. In our previous works, we prepared a cationic micelles based on chitosan and poly-(N-3-carbobenzyloxylysine) (CS-g-PZLL), but transfection ratio of CS-g-PZLL to Hela cell was low. Herein, to improve the transfection efficiency of CS-g-PZLL, curcumin was loaded in the CS-g-PZLL micelle. After irradiation, the obtained curcumin loaded micelle showed a better transfection, and the p53 protein expression in Hela cells was higher. The apoptosis assay showed that the complex could induce a more significant apoptosis to Hela cells than that of curcumin or p53 used alone, and the curcumin loaded micelle inducing apoptosis was best after irradiation. Therefore, CS-g-PZLL is a safe and effective carrier for the codelivery of drug/gene, and curcumin could be used as a photosensitizer to induce a photoenhanced gene transfection, which should be encouraged in improving transfection and tumor therapy.

New hybrid gels were prepared from the gelation of glycol-modified tetraethoxysilane (TEOS) in the presence of O-2-hydroxy-3-(trimethylammonio)propyl guar gum (HTPG), and were then used for the in situ encapsulation of papain. Different from the sol–gel process based on commonly used TEOS, the biofriendly sol–gel process developed in this study could be conducted rapidly at ambient temperature without the addition of any organic solvent or acidic catalyst. In particular, the mechanical strength and microstructure of resultant hybrid gel matrix could be modulated by HTPG amount. In comparison with free papain, the encapsulated papain is characteristic of improved enzymatic activity, thermal and storage stability as well as good reusability.

Traditional torsional resonators, often obtaining the viscoelastic moduli of complex fluids only at one or several given discrete frequencies, lack the continuously varying frequency capability. This is an obvious disadvantage of the traditional torsional resonator technique. This paper presents an improved strategy, based on our previous discrete-frequency-measuring method (Wang et al., J Rheol 52:999–1011, 2008), to overcome such restriction and thus accomplish the continuously varying frequency capability of the traditional torsional resonator for measuring the viscoelastic properties of complex fluids. The feasibility of this strategy is demonstrated with the Newtonian fluids (several water–glycerol solutions) of viscosities varying from 10 to 1,400 cp by using our homemade torsion resonator apparatus in the 10 ~ 2,500 rad/s frequency range (continuous frequencies). Some results for typical viscoelastic polymers (two polyethylene oxide (PEO) aqueous solutions) are also given. Additionally, a comparison of the PEO results is made with the common rheometer technique. It is demonstrated that this improved strategy could enable the traditional torsional resonators, with one oscillating resonance mode, to work as the microrheological technique and the common rheometer technique in the continuous frequency range.

In an attempt to develop a biofriendly sol-gel route for the rapid formation of biofunctional silica gels, a biopolymer with good biocompatibility was used to assist the gelation of glycol-modified tetraethoxysilane (GMT) in aqueous system without the addition of any organic solvents. It was found that the biopolymer used could act as an effective accelerator for the sol-gel transition of GMT and an increase of its amount could shorten greatly the gelation time. For such a gelation reaction, its apparent activation energy was determined to be 64.9 kJ/mol according to the Arrhenius equation. In particular, the kinetic mechanism for the formation of the silica gel was investigated by using dynamic theological data and a scaling fractal model. It was revealed that the biopolymer used could change the sol-gel transition mechanism from reaction-limited kinetics to diffusion-limited kinetics. Circular dichroism analyses confirmed the suitability of using the resultant silica gel for the in situ protein encapsulation.

A commercial organophilic montmorillonite (Claytone APA) was used to modify the properties of polystyrene by in-situ incorporation method, in which the polymerization of styrene was carried out in the presence of Claytone APA. It was found that this organoclay could be easily dispersed and swollen in styrene monomer. For the resultant polystyrene nanocomposites, the intercalated microstructure was confirmed by X-ray diffraction (XRD) and transmission electron microscopy (TEM), and their thermal and viscoelastic properties were investigated by means of thermogravimetric analyses and rheological parameter measurements. Compared with pure PS, the modified PS samples investigated are characteristic of enhanced thermal stability, stronger shear-thinning behavior as well as greater storage and loss moduli.

A new type of sol-gel organic-inorganic hybrid material was developed and used for the fabrication of an amperometric hydrogen peroxide biosensor. This material was prepared from natural chitosan and recently introduced completely water-soluble precursor, tetrakis(2-hydroxyethyl) orthosilicates (THEOS), by the sol-gel process without the addition of organic solvents and catalysts. The gelation time for the sol-gel transition and dynamic rheological properties of the resultant gel matrix could be modulated by the amount of added THEOS. The structure of the hybrid gel was made up of a network and spherical particles, as confirmed by SEM observation. By electrochemical experiments, it was found that such a hybrid gel matrix could retain the native biocatalytic activity of the entrapped horseradish peroxidase and provide a fast amperometric response to hydrogen peroxide. The linear range for the determination of hydrogen peroxide was found to be from 1.0 x 10(-6) to 2.5 x 10(-4) mol/L with a detection limit of 4.0 x 10(-7) mol/L. The apparent Michaelis-Menten constant was determined to be 2.198 mmol/L. To improve the analytical characteristics of the fabricated biosensor, the effects of applied potential and pH value on the steady-state current were studied. Under the optimized experimental conditions, the fabricated biosensor was found to have good analytical performance, reproducibility, and storage stability.

Cationic micellar nanoparticles for chemotherapeutic drugs and therapeutic gene co-delivery were prepared based on a poly-(N-e-carbobenzyloxy-l-lysine) (PZLL) and dendritic polyamidoamine (PAMAM) block copolymer (PZLL-D3). PZLL-D3 was synthesized by a copper-catalyzed azide alkyne cyclization (click) reaction between α-alkyne-PZLL and azide focal point PAMAM dendrons. Its structure was characterized by (1)H NMR and FTIR, and its buffering capability was determined by acid-base titration. MTT, agarose gel electrophoresis and flow cytometry studies showed that PZLL-D3 revealed low in vitro cytotoxicity, strong pDNA condensation ability, protection of pDNA against deoxyribonuclease I degradation and high gene transfection efficiency in 293T and HeLa cells. In addition, the micellar nanoparticles delivered pDNA and anticancer drug doxorubicin (DOX) simultaneously and efficiently to tumor cells, and the DOX loaded nanoparticles showed sustained in vitro release at pH=7.4 and 5.8.

To develop biocompatible sol-gel silica matrix for the encapsulation of biomolecules or drugs, a novel water-soluble silica precursor, tetrakis(2-hydroxyethyl)orthosilicates (THEOS), was used in combination with a water-soluble polysaccharide derivative, hydroxypropyl guar gum (HPGG). We found that the introduction of HPGG could trigger and accelerate the sol-gel transition of THEOS in water and induce rapid formation of homogeneous gel matrix without the addition of any organic solvents or catalysts. Moreover, added HPGG macromolecules had a great influence on the network structure and particle dimension in the silica gel matrix, as confirmed by scanning electron microscope (SEM) observation. From the time sweep rheological measurements, it was found that a higher HPGG amount could lead to shorter gelation time for the sol-gel transition. From the strain and frequency sweep rheological experiments, it was found that the resultant silica matrix containing a higher amount of HPGG exhibited a narrower linear viscoelastic region, a higher dynamic muduli, and greater complex viscosity. In particular, the gel strength of the silica matrix could be modulated by the amount of HPGG. By investigating the controlled release of vitamin B12 from the sol-gel silica matrixes, a strong dependence of the release profile on the amount of introduced HPGG was observed. In this case, a higher HPGG amount resulted in lower release rate.

In this work, a series of polyamidoamine (PAMAM) dendrimer-functionalized mesoporous silica nanoparticles (MSNs) with predictable and adjustable cationic charge densities for gene delivery were designed, synthesized and characterized. The 'clickable' MSNs with controlled and randomly distributed azide groups were synthesized by co-condensation method, and PAMAM dendrimer was conjugated to MSNs via quantitative click modification. The structures of PAMAM-functionalized MSNs were characterized by FTIR, XRD and TEM analyses. Dendrimer-functionalized MSNs formed complexes with plasmid DNA (pDNA), and the complexes were successfully transfected into human kidney cell 293 T. The in vitro cytotoxicity and gene transfection efficacy were also investigated.

For the in situ incorporation of multiwalled carbon nanotubes (MWCNTs) into sol–gel silica matrix for electrochemical sensing, a water-soluble carboxymethylchitosan derivative having pendant pyrene moieties (CMCSPy) was prepared and used. It was found that such a modified polysaccharide could act both as the stabilizing agent for preparing colloidally stable dispersion of MWCNTs in an aqueous system and the accelerating agent for inducing rapidly the sol–gel transition of water-soluble siliceous precursor, tetrakis(2-hydroxyethyl)orthosilicates (THEOS). By dissolving directly THEOS in aqueous MWCNT dispersions stabilized by CMCSPy, the gel matrices incorporated with well-dispersed MWCNTs could be obtained in mild conditions. Moreover, the incorporation of MWCNTs could shorten the time interval for the gel formation and enhance the gel strength, as confirmed by rheological analyses. By electrochemical experiments, it was found that the as-prepared gel matrix with MWCNTs could be used to construct the amperometric hydrogen peroxide biosensor with an improved response due to the favorable electrochemical characteristics of the incorporated MWCNTs.