Cationic Alternating Polypeptide Fixed on Polyurethane at Multiple Sites for Excellent Antibacterial and Antifouling Properties.

Bacterial infection and blockage are severe problems for polyurethane (PU) catheters and there is an urgent demand for surface-functionalized polyurethane. Herein, a cationic alternating copolymer comprising allyl-substituted ornithine and glycine (allyl-substituted poly(Orn-alter-Gly)) with abundant carbon-carbon double bond functional groups (C═C) is designed. Polyurethane is prepared with a large quantity of C═C groups (PU-D), and different amounts of allyl-substituted poly(Orn-alter-Gly) are grafted onto the PU-D surface (PU-D-2%AMPs and PU-D-20%AMPs) via the C═C functional groups. The chemical structures of the allyl-substituted poly(Orn-alter-Gly) and polyurethane samples (PU, PU-D, PU-D-2%AMPs, and PU-D-20%AMPs) are characterized and the results reveal that allyl-substituted poly(Orn-alter-Gly) is decorated on the polyurethane. PU-D-20%AMPs shows excellent antibacterial activity against Escherichia coli, Enterococcus faecalis, and Staphylococcus aureus because of the high surface potential caused by cationic allyl-substituted poly(Orn-alter-Gly), and it also exhibits excellent long-term antibacterial activity and antibiofilm properties. PU-D-20%AMPs also has excellent antifouling properties because the cationic copolymer is fixed at multiple reactive sites, thus avoiding the formation of movable long chain brush. A strong surface hydration barrier is also formed to prevent adsorption of proteins and ions, and in vivo experiments reveal excellent biocompatibility. This flexible strategy to prepare dual-functional polyurethane surfaces with antibacterial and antifouling properties has large potential in biomedical implants.

Super-Resolution Fluorescence Imaging of Spatial Organization of Proteins and Lipids in Natural Rubber.

Natural rubber (NR) with proteins and lipids has superior mechanical properties to its synthetic counterpart, polyisoprene rubber. However, it is a challenge to unravel the morphology of proteins and lipids. Here we used two-color stochastic optical reconstruction microscopy (STORM) to directly visualize the spatial organization of proteins and lipids in NR. We found that the proteins and lipids form an interdispersed stabilizing layer on the surface of NR latex particles. After drying, the proteins and lipids form aggregates of up to 300 nm in diameter. The aggregates physically interact with the terminal groups of polyisoprene chains, leading to the formation of a network, which contributes to the high elasticity and mechanical property of NR. If we remove proteins in NR, the large phospholipid aggregates disintegrate into small ones. However, it does not decompose the network but rather reduces the effective cross-linking density, thus the deproteinized NR is still elastic-like with decreased mechanical property. Removing both proteins and lipids wholly decomposes the network, thus, results in a liquid-like behavior of the rubber. The STORM measurements in this paper enable more insight into the structure-property relationship of NR, which also shows a great potential of STORM in studying the fine structure of polymeric materials and nanocomposites.

Improved siRNA delivery efficiency via solvent-induced condensation of micellar nanoparticles.

Efficient delivery of short interfering RNA (siRNA) remains one of the primary challenges of RNA interference therapy. Polyethylene glycol (PEG)ylated polycationic carriers have been widely used for the condensation of DNA and RNA molecules into complex-core micelles. The PEG corona of such nanoparticles can significantly improve their colloidal stability in serum, but PEGylation of the carriers also reduces their condensation capacity, hindering the generation of micellar particles with sufficient complex stability. This presents a particularly significant challenge for packaging siRNA into complex micelles, as it has a much smaller size and more rigid chain structure than DNA plasmids. Here, we report a new method to enhance the condensation of siRNA with PEGylated linear polyethylenimine using organic solvent and to prepare smaller siRNA nanoparticles with a more extended PEG corona and consequently higher stability. As a proof of principle, we have demonstrated the improved gene knockdown efficiency resulting from the reduced siRNA micelle size in mice livers following intravenous administration.

[Real temperature of the continuous-wave pluggers].

OBJECTIVE: To measure the real temperatures on the pluggers of three continuous-wave devices, and to provide theoretical reference to evaluate thermal damage and heat's influence on the filling materials. METHODS: The dual channel K type thermocouple was contacted to various sizes' pluggers in three different continuous-wave devices (BeeFill, Elements, B&L), and the highest temperatures at different points (tip, and 2 mm, 5 mm, 10 mm from the tip) of the pluggers (preset temperature was 200 °C) were recorded. The measurements were performed 5 times. T-test was used to compare the real temperatures at the tips with that set on the display and one-way ANOVA was used to compare the temperatures of the pluggers in different devices, sizes and points. RESULTS: The highest temperature was at the tip of BeeFill 40/0.03 plugger (198.7±7.7) °C, but there was on statistical differences between that and the preset temperature 200 °C. The temperatures of the remaining pluggers were obviously lower than 200 °C (P<0.05). The lowest temperature of the pluggers was detected at 10 mm from the tip of BeeFill 60/0.06 plugger (69.9±4.0) °C. The highest temperature of each plugger was detected at the tip or 2 mm from the tip (112.1 to 198.7 °C,and the median was 140.8 °C). CONCLUSION: The real temperature of most continuous-wave pluggers included in this study is below the set temperature 200 °C.

Influence of surface properties on the adhesion of bacteria onto different casings.

Bacteria adhere to the surfaces of sausage casing and form biofilms, which causes food spoilage and quality deterioration. However, bacterial adhesion to the casing surfaces has not received enough attention and has not been extensively studied. In this study, the effect of the physicochemical properties of casing surfaces on bacterial initial adhesion were investigated with Leuconostoc mesenteroides as model bacteria. The adhesion of Leuconostoc mesenteroides onto 5 types of casings were systematically investigated, including animal casings, collagen casings, cellulose casings, fiber casings, and nylon casings, which are the most frequently encountered casings in sausage processing. It was found that the number of viable cells on the casings following the trend as: animal casings > collagen casings > fiber casings > cellulose casings > nylon casings after 4 h of incubation time. This phenomenon might be due to the different physicochemical properties of the different casings. Therefore, physicochemical factors, including zeta potential, hydrophobicity and roughness of casings, zeta potential and hydrophobicity of Leuconostoc mesenteroides, were further characterized. In terms of hydrophobic interactions, the results showed that the number of bacteria attached to the casings did not conform to the trend of hydrophobic interaction. In terms of electrostatic interactions, the results showed that the number of bacteria attached to the casings did not conform to the trend of hydrophobic interaction. The casings with different surface roughnesses in a range of 1.67-20.83 µm, the variation of bacterial adhesion quantity was in good agreement with the variation trend of casing roughness, the result showed that the surface roughness was the key factor dominating the bacterial adhesion rate compared with the surface hydrophobicity and zeta potential. The results give new insights to explore the mechanism of bacterial adhesion on casings and prevent sausage spoilage.

An anthracene extended viologen-incorporated ionic porous organic polymer for efficient aerobic photocatalysis and antibacterial activity.

A new conjugated ionic porous organic polymer (AN-POP), incorporated with anthracene-extended viologen, has been rationally designed and prepared to explore its dual functions in photocatalytic oxidation and bacterial killing. Compared with its anthracene-free counterpart (BD-POP), AN-POP showed a superior photocatalytic oxidation performance and antibacterial activity demonstrating the critical role of an anthracene-extended viologen structure.

Composite inclusion complexes containing hyaluronic acid/chitosan nanosystems for dual responsive enrofloxacin release.

In order to overcome treatment difficulty of S. aureus infections, a pH/hyaluronidase dual responsive enrofloxacin-cyclodextrin (ß-CD) inclusion complexes (IC) containing hyaluronic acid/chitosan (HA/CS) self-assemble composite nanosystems covered by poloxamer 188 (F68) was firstly explored for targeted "on-demand" delivery. The FTIR, DSC and PXRD showed that enrofloxacin was embedded into IC and then distributed into F68 coating nanogels formulated by electrostatic interaction between CS and HA. The optimal nanosystems of 118.8 ± 30.7 nm showed excellent stability and responsive release in the acid medium, hyaluronidase containing medium, and LB broth medium where S. aureus present. The nanosystems displayed strong surface adsorption on S. aureus and enhanced activity against S. aureus. It had stronger sustained release than the polymeric nanoparticles formulated by entrapping of IC into F68 and the single HA/CS nanogels. This study provides a promising multi-functionalized nanosystems to overcome the treatment challenge of S. aureus and other bacterial infections.

The Nd:YAG Laser or Combined with Er:YAG Laser Therapy for Oral Venous Lakes.

Objective: The aim of the present study was to investigate the clinical treatment effect on oral venous lakes (OVL) treated with neodymium-doped yttrium aluminum garnet (Nd:YAG) laser or a combination of erbium-yttrium aluminum garnet (Er:YAG) laser. Patients and methods: Between June 2015 and March 2017, nine patients, suffering from OVL in the mandibular regions, were treated with Nd:YAG laser or combination of Nd:YAG laser and Er:YAG laser in our department. The Nd:YAG laser was mainly performed for the treatment of nine initial lesions. The preset parameters were as follows: average power of 5 W, frequency of 100 Hz, microshort pulse (MSP), tip size of 300 µm, spot size of 3 mm, irradiation distance of 3-4 mm, and speed of 1-2 mm/sec, sequential treatment. The power density at work was 57 W/cm2. If postoperative scars occurred after the Nd:YAG treatment, the Er:YAG laser was used. The parameters were set as follows: power of 3.75 W, energy of 150 mJ, frequency of 25 Hz, very long pulse (VLP), tip size of 0.6 mm, 40% water, and 60% gas. The patients were followed up for 4-8 weeks. The therapeutic results were graded on a 4-point scale system. Adverse effects after laser treatment were evaluated and managed accordingly. Results: With single Nd:YAG laser, the therapeutic outcome was excellent in seven patients (77.8%) and good in two patients (22.2%). Scar tissue was encountered in two patients 2 weeks after Nd:YAG laser therapy, and then Er:YAG laser was used for the scar removal. No mucosal necrosis was found in any of the patients. Conclusions: The Nd:YAG laser or combined with Er:YAG laser was an effective and safe treatment for patients with OVL in the mandibular region.

High-Potential surface on zirconia ceramics for bacteriostasis and biocompatibility.

Bacteria easily adhere, colonize, and form biofilm on oral implants subsequently causing periimplantation periarthritis and mechanical loosening. Previous studies show that a high potential surface on polymeric implants can achieve surface bacteriostasis without side effects. In this study, a high surface potential is introduced to zirconia ceramics to mitigate bacterial infection. Carbon and nitrogen plasma immersion ion implantation (C-PIII and N-PIII) are conducted on zirconia ceramic samples sequentially to elevate the surface potential. The surface with a high potential but without ion leaching exhibits excellent antibacterial effects against oral bacteria and little bacterial resistance is triggered. The surface also has high strength and excellent biocompatibility. The nitrogen-containing inorganic structure with high potential can actualize bacteriostasis and biocompatibility on zirconia ceramics simultaneously and this new strategy can enhance the antibacterial ability of oral implants.

Nanoparticles for antiparasitic drug delivery.

As an emerging novel drug carrier, nanoparticles provide a promising way for effective treatment of parasitic diseases by overcoming the shortcomings of low bioavailability, poor cellular permeability, nonspecific distribution and rapid elimination of antiparasitic drugs from the body. In recent years, some kinds of ideal nanocarriers have been developed for antiparasitic drug delivery. In this review, the progress of the enhanced antiparasitic effects of different nanoparticles payload and their influencing factors were firstly summarized. Secondly, the transport and disposition process in the body were reviewed. Finally, the challenges and prospects of nanoparticles for antiparasitic drug delivery were proposed. This review will help scholars to understand the development trend of nanoparticles in the treatment of parasitic diseases and explore strategies in the development of more efficient nanocarriers to overcome the difficulty in the treatment of parasite infections in the future.

CD44 targeted redox-triggered self-assembly with magnetic enhanced EPR effects for effective amplification of gambogic acid to treat triple-negative breast cancer.

Gambogic acid (GA) is a natural anti-tumor drug whose application is restricted by its poor aqueous solubility and inefficient bioavailability. Developing nanomaterials with excellent biocompatibility can amplify the therapeutic effects of GA. In this study, a tumor-targeted redox controllable self-assembled nano-system with magnetic enhanced EPR effects (mPEG-HA/CSO-SS-Hex/SPION/GA) was developed to improve the anticancer efficacy of GA. The nano-system is constituted by three layers: the outer layer is mono-aminated poly(ethylene glycol) grafted hyaluronic acid (mPEG-HA), which can target the CD44 receptor in breast cancer cells; the middle layer consists of disulfide linked hexadecanol (Hex) and chitosan oligosaccharide (CSO) to control the drug release by reduction response; the core layer is superparamagnetic iron oxide nanoparticles (SPION), which can enhance the EPR effect by magnetic guidance and contribute to GA entrapment. Different experiments were performed to characterize the complex self-assembly, and the cytotoxicity, pharmacokinetics, and in vivo antitumor activity of the self-assembly were investigated to evaluate its anti-tumor effects. The results revealed that mPEG-HA/CSO-SS-Hex/SPION/GA is an excellent nanosystem with appropriate size and sensitive responsiveness; it can accumulate in tumor sites and achieve excellent therapeutic effects on triple-negative breast cancer (TNBC). In summary, a CD44-targeted redox-triggered self-assembly nanosystem with magnetic enhanced EPR effects was developed for effective amplification of GA; it has potential to act as an effective carrier in drug delivery for chemotherapy of TNBC.

Influence of Warm Vertical Compaction Technique on Physical Properties of Root Canal Sealers.

INTRODUCTION: The aim of this study was to evaluate the influence of warm vertical compaction on the physical properties of root canal sealers. METHODS: The physical properties of 4 sealers (zinc oxide -eugenol [ZOE], AH Plus [Dentsply International, York, PA], RoekoSeal [Roeko/Coltene/Whaledent, Langenau, Germany], and iRoot SP [Innovative Bioceramix, Vancouver, Canada]) were tested. The setting time and flow of these sealers were measured at standard and high temperatures using ISO 6876 (2012) specifications. The percentage of voids in each sealer after complete setting at 37°C and 140°C was analyzed under a stereoscopic microscope. RESULTS: The setting time of ZOE sealer increased significantly from 144.0 ± 4.1 minutes to 274.2 ± 7.4 minutes when the temperature increased from 37°C to 140°C, whereas there was a significant reduction in the other 3 sealers. At 37°C, the setting time of AH Plus, iRoot SP, and RoekoSeal was 543.8 ± 16.4, 245.8 ± 15.9, and 49.3 ± 1.5 minutes, and at 140°C the setting time decreased significantly to 12.9 ± 0.7, 14.2 ± 0.6, and 2.7 ± 0.4 minutes (P < .05). The flow of AH Plus increased when the temperature changed from 25°C to 140°C (P < .05), whereas the flow reduced for RoekoSeal and iRoot SP (for RoekoSeal from 24.8 ± 0.9 to 12.4 ± 1.3 mm and for iRoot SP from 22.9 ± 0.9 to 13.3 ± 1.5 mm) (P < .05). However, the flow of ZOE sealer was unaffected by the high temperature. ZOE sealer and iRoot SP exhibited a reduction of porosity at a high temperature (P < .05). CONCLUSIONS: Warm vertical compaction influenced some properties (the setting time, flow, and porosity) of 4 sealers. A significant reduction of setting time and flow was found in RoekoSeal and iRoot SP sealers at a high temperature.

Preparation, characterization and pharmacokinetics of doxycycline hydrochloride and florfenicol polyvinylpyrroliddone microparticle entrapped with hydroxypropyl-ß-cyclodextrin inclusion complexes suspension.

In order to effectively control the bacterial pneumonia in pigs, doxycycline hydrochloride (DoxHcl) and florfenicol (FF) microparticle suspension together with inclusion complexes was prepared by using hydroxypropyl-ß-cyclodextrin (HP-ß-CD) as host molecules, polyvinylpyrroliddone (PVP) as polymer carriers and hydroxypropyl methyl cellulose (HPMC) as suspending agents. In vitro antibacterial activity, properties, stability and pharmacokinetics of the suspension were studied. The results demonstrated that DoxHcl and FF had a synergistic or additive antibacterial activity against Streptococcus suis, Actinobacillus pleuropneumoniae and Haemophilus parasuis. The size, polydispersity index and zeta potential of microparticles were 1.46 ± 0.06 µm, 0.30 ± 0.02 and 1.53 ± 0.04 mV, respectively. The encapsulation efficiency (EE) of DoxHcl and FF was 45.28% ± 3.30% and 89.69% ± 2.71%, respectively. The re-dispersed time and sedimentation rate of the suspension were 1 min and 1. The suspension went through the 9-gage needle smoothly with withdrawal volume of 9.12 ± 0.87 mL/min. The suspension showed good stability when stored away from light, no irritation at the injection site and sustained release in PBS buffer. After intramuscular administration to pig, DoxHcl and FF could maintain over 0.15 µg/mL for 72 h. Compared to the control injection, the suspension increased the elimination half-life (T½ke) as well as mean residence time (MRT) of DoxHcl from 5.73 to 9.77 h and from 12.02 to 18.81 h, and those of FF from 12.02 to 26.19 h and from 12.02 to 28.16 h, respectively. The suspension increased the bioavailability of DoxHcl and FF by 1.74 and 1.13-fold, respectively. These results suggest that the compound suspension is a promising formulation for pig pneumonia therapy.

[Study on purification of total flavonoids from seed residue of Hippophae rhamnoides with macroporous resin].

OBJECTIVE: To study the conditions and parameters of purifying total flavonoids from seed residue of H. rhamnoides. METHOD: Absorption capacity of three resins for total flavonoids was compared. With the yield and purity as indexes, the process of absorbing and purifying total flavonoids from seed residue with D101 macroporous resin absorbent was selected by orthogonal design. RESULT: The D101 resin was the best of the three resins and its absorption capacity was determined to be 63.00 mg x g(-1) wet resin. The optimum process condition was 30% ethanol as eluting solvent, wet resin vs crude herbs: 2:1, diameter vs height: 1:10, eluting solvent vs crude herbs: 10:1, absorbing time for 3 h. The yield of total flavonoids from seeds residue of H. rhamnoides by this process was 2.39%, and the purity reached 64.81%. CONCLUSION: The process is simple and convenient and the regeneration of resin is easy. So this method of purification is advisable.

Optimizing dendritic cell preparation for fusion with melanoma cells.

BACKGROUND: Fusion of dendritic cells (DCs) with melanoma cells could reinforce the antigenicity of tumors as a strategy for the treatment of malignant melanoma. However, the insufficient quantity of DCs and the low fusion efficiency limits the development of such approach. OBJECTIVE: To define the dosage of the stimulating factors as well as the induction condition for the optimal DCs preparation and cell fusion. METHODS: DCs were generated from murine bone marrow cells, and cultured with four different concentrations of the granulocyte-macrophage colony-stimulating factor (GM-CSF) and interleukin-4 (IL-4). DCs were confirmed to be mature by detecting the expression of MHC-II, CD11c, CD80, and CD83 by flow cytometry. DCs-melanoma fusion cells were generated using polyethylene glycols (PEG) with different molecular weights and the fusion efficiency was detected by fluorescence-activated cell sorter (FACS). RESULTS: The largest quantity of DCs was found when cells were cultured with 1000 U/ ml of GM-CSF and 500 U/ml of IL-4 (1.69 ± 0.04 ×106 ml⁻¹, p<0.001 when compared with the other three groups). The expression levels of MHC-II and CD83 on day 7 after incubation were significantly lower than those on day 3 (MHC-II: p<0.001; CD83: p<0.001). The efficiency of cell fusion under induction of PEG-3000 was significantly higher than that of PEG-4000 (15.4 ± 0.56% vs. 11.1 ± 0.45%, p<0.001). CONCLUSIONS: The largest quantity for mature DCs was stimulated with 1000 U/ml of GM-CSF and 500 U/ml of IL-4 and the highest fusion efficiency was under induction of PEG-3000.

FK506-loaded chitosan conduit promotes the regeneration of injured sciatic nerves in the rat through the upregulation of brain-derived neurotrophic factor and TrkB.

FK506 has been shown to exert neurotrophic and neuroprotective effects, but its long-term application for nerve regeneration is limited. This study evaluated the potential application of a novel FK506-loaded chitosan conduit for peripheral nerve repair, and explored the underlying mechanism. A sciatic nerve injury model was created in male Wistar rats, which were then randomly divided into three treatment groups (n=40, each): chitosan-only, chitosan+FK506 injection, and FK506-loaded chitosan. We found significant recovery of normal morphology of sciatic nerves and higher density of myelinated nerve fibers in rats treated with FK506-loaded chitosan. Similarly, the total number of myelinated nerve fibers, myelin sheath thickness, and axon diameters were significantly higher in this group compared with the others, and the compound muscle action potentials and motor nerve conduction velocity values of sciatic nerves were significantly higher. BDNF and TrkB levels in motor neurons were highest in rats treated with FK506-loaded chitosan. In conclusion, FK506-loaded chitosan promoted peripheral nerve repair and regeneration in a rat model of sciatic nerve injury. These effects are correlated with increased BDNF and TrkB expression in motor neurons.

[Clinical analysis of radionuclide bone scan in patients with facial asymmetry].

PURPOSE: To study the radionuclide distribution in mandible of patients with facial asymmetry and help to select proper time and type of treatment. METHODS: The control group included 29 people with no facial asymmetry, while the experimental group consist of 207 patients with facial asymmetry. The radioactive count in 29 normal controls and 207 patients with facial asymmetry were measured and compared using 99mTc-MDP intake percentage in mandibular condyle, ramus and body. SPSS13.0 software package was used for statistical analysis. RESULTS: There was significant difference between adult and adolescent patients in 99mTc-MDP intake of the condyles. There was no significant difference between male and female in the 99mTc-MDP intake of the condyles. The 99mTc-MDP intake difference percentage was (22.50±1.67)%, (6.93±1.02)% and (13.67±0.95)% in mandibular condyle, ramus and body, respectively. The intake difference value of the condyle was the biggest. CONCLUSIONS: The mandible growth trend is different from the body's growth and development trend. We can analyze the trend of mandible development by radionuclide bone scan and select proper time and type of treatment.

Plasmid-templated shape control of condensed DNA-block copolymer nanoparticles.

DNA-containing micellar nanoparticles with distinctly different and highly uniform morphologies are prepared via condensation of plasmid DNA with a block copolymer of polyethylene glycol and a polycation in solvents of different polarity. Molecular dynamics simulations explain the underlying mechanism.

The transport mechanisms of polymer nanoparticles in Caco-2 epithelial cells.

As the primary physiological barrier, intestinal epithelial cells regulate the transportation of oral therapeutic agents including nanomedicines which significantly improves the bioavailability of many drugs. However, currently there seems in the lack of comprehensive understanding on nanoparticle transport in intestinal epithelial cells as well as the mechanisms related. So, in an attempt to illustrate the profile of nanoparticle transport in intestinal epithelial cells, Caco-2 cells and polymer nanoparticles (PNs) were used as the models to explore the whole transport process including endocytosis, intracellular trafficking, exocytosis and transcytosis. Via various techniques, the transport pathways of PNs in Caco-2 cells and their mechanisms were clarified. Firstly, the transport was characterized by its non-specificity. The co-mediation of clathrin, lipid raft/caveolae and macropinocytosis as well as the co-involvement of different proteins like actins, protein tyrosine kinase (PTK) and cyclooxygenase (COX) were found in the endocytosis of PNs. The endocytosed PNs could transport to apical early endosome (AEE) and then from AEE to lysososmes via AEE/late endosome (LE)/lysosome pathway, as well as to recycling endosome compartment (REC) or endoplasmic reticulum (ER) through AEE/REC and AEE/ER pathways, respectively. Both ER/Golgi and Golgi/REC/plasma membrane (PM) pathways were involved in the exocytosis of PNs. The transcytosis of PNs across the cell monolayer was very low with a ratio less than 0.5%, due to complicated reasons. Secondly, the transport was evidenced by its partial energy-dependency. Beside the energy-dependent transport mediated by some proteins, quantitative study demonstrated the obvious internalization as well as surface binding of PNs at both 37 °C and 4 °C, but significantly higher at 37 °C. Interestingly, the consistency between surface binding and internalization at each temperature was found, suggesting that cell binding was the precondition and key step for the following endocytosis. The involvement of both energy dependent and independent mechanism was also observed in the exocytosis and transcytosis process of PNs. Finally, there were opposite mechanisms found between the exocytosis and endocytosis of PNs, including the regulation role of lipid raft/caveolae, COX and Golgi complex, which also contributed to the fact of "easy entry and hard across" for PNs. Overall, this study depicts a clear picture of nanoparticle transport in Caco-2 epithelial cells characterized by non-specificity, partial energy-dependency and low transcytosis.

Bilayer matrix composed of polycation/DNA complex and sodium alginate gel as a tumor cell catcher.

A bilayer matrix consisting of TABP-SS/DNA complexes and sodium alginate gel is formed via electrostatic interaction. In vitro cell adhesion, proliferation and transfection of the bilayer matrix are investigated in HepG2, HeLa and COS7 cells. Results show that this matrix can only promote tumor cell attachment and growth. Compared with normal cells, the bilayer matrix exhibits significantly higher transfection efficacy in tumor cells. Cell co-culture competitive transfection assay shows that the cell uptake of TABP-SS/DNA complexes is significantly enhanced in tumor cells rather than normal cells under the co-culture competitive condition, which confirms that TABP-SS/DNA complexes have strong tumor cell selectivity and tumor targeting transfection ability.