Self-assembled ternary hybrid nanodrugs for overcoming tumor resistance and metastasis

Traditional chemotherapy exhibits a certain therapeutic effect toward malignant cancer, but easily induce tumor multidrug resistance (MDR), thereby resulting in the progress of tumor recurrence or metastasis. In this work, we deigned ternary hybrid nanodrugs (PEI/DOX@CXB-NPs) to simultaneously combat against tumor MDR and metastasis.

TGA/Chemometrics addressing innovative preparation strategies for functionalized carbon nanotubes / 药物分析学报

In this work, functionalized carbon nanotubes (CNTs) using two polyamine polymers, polyethyleneimine (PEI) and polyamidoamine dendrimer (PAMAM), were investigated by thermal analysis in order to address preparation strategies to obtain low cytotoxic compounds with the ability to conjugate micro-RNAs and, at the same time, to transfect efficiently endothelial cells. Thermogravimetric analysis (TGA) was coupled to chemometrics as a novel analytical strategy to characterize functionalized CNTs from different preparation conditions. In particular, two starting materials were considered:very small CNTs and carboxylated CNTs (CNT-COOH) in order to examine the affinity with polymers. Chemometrics permitted to compare results from TGA and to investigate the effect of a number of factors affecting the synthesis of coated nanotubes including a different amount of involved polymer and the time required for the suspension for a satisfactory and reproducible preparation procedure. The results demonstrated the effectiveness of TGA as a tool able to address synthesis of coated CNTs to be employed as efficient drug delivery vectors in biomedical applications.

In Vitro Evaluation of Poloxamer 188 Modified Polyethyleneimine as Gene Vectors / 医药导报

Objective To modify polyethyleneimine (PEI) by using Poloxamer 188 (P188) , and evaluate its related feature as carriers of genes in vitro. Methods PEI was modified through conjugating one hydroxyl group of P188 to the amino group of PEI by carbonate method. Structural analysis of synthesized polymer was performed by using 1H-NMR. The particle size and Zeta potential of synthesized polymer /DNA complexes were measured. The cytotoxicity of the complexes was evaluated using MTT method in MCF-7 cells, HeLa cells and HepG2 cells. The pGL3-lus was used as a reporter gene, and the transfection efficiency of complexesat HeLa cells was evalutated by measuring activity of luciferase. Results The result of 1H-NMR showed the purity of these synthesized polymers was high. The particle size of complexes were decreased with the increment of N /P ratios. The Zeta potential of complexes increased with the increment of N /P ratios. The cytotoxicity of the complexes increased with the increment of N /P ratios. The synthesized polymers showed lower cytotoxicity than unmodified PEI. The new synthesized polymers had maintained the high transfection efficiency at high N /P ratios. In particular, the optimal transfection efficiency of (P188) 1- PEI (N /P = 24) was significantly higher than that of PEI (N /P = 6) . Conclusion The P188 modifed PEI can serve as a effective non-viral gene carriers to transfect Hela cells.

Synthesis and evaluation of a dendritic poly(L-glutamic acid)-graft-polyethylenimine copolymer as an efficient gene delivery vector / 药学学报

The study was designed to synthesize a novel dendritic copolymer composed of polyamidoamine dendrimer G0 as the inner core and poly(L-glutamic acid) grafted low molecular weight polyethylenimine (PGLP) as surrounding arms for gene delivery vector. The molecular structure of PGLP was confirmed by 1H NMR (proton nuclear magnetic resonance spectroscopy). The DNA combination capability of PGLP was examined by gel retardation electrophoresis. The particle sizes and zeta potentials of PGLP/pDNA complexes were determined by dynamic light scattering (DLS). The cytotoxicity of PGLP was evaluated by Cell Counting Kit-8 (CCK-8) and hemolysis assays, which was approved by Research Ethics Committee of the First Affiliated Hospital of Nanchang University. The in vitro transfection efficiency of PGLP was measured by a flow cytometry. The results of physicochemical properties suggested that PGLP could self-assemble with DNA to form complexes with average particle sizes of about 105-200 nm and zeta potentials of about +10 - +28 mV, which could protect DNA from serum degradation. The results of biological properties suggested that PGLP showed more higher transfection efficiencies but lower cytotoxicity than PEI 25K or Lipofectamine 2000 in various cell lines (HEK 293T, HeLa, BEL 7402, RASMC). Importantly, it was found that PGLP/pDNA complexes at w/w = 8 showed more strong serum-resistant capacity than PEI 25K/pDNA complexes. Therefore, PGLP is a promising candidate vector for gene delivery.

Desarrollo de vectores génicos basados en polímeros sintéticos: PEI y PDMAEMA / Development of genetic vectors based on synthetic polymers: PEI and PDMAEMA

RESUMEN En años recientes hubo un auge del uso de terapias génicas para el tratamiento de enfermedades de gran incidencia, como el cáncer. Generalmente, estas se basan en la liberación de material genético como plásmidos, en el núcleo celular, con lo cual se corrige una función o se induce la producción de proteínas deficientes a nivel fisiológico. Para llevar a cabo la terapia génica se requiere de vectores capaces de encapsular el material genético y garantizar su entrega en el núcleo celular. Los polímeros catiónicos sintéticos han llamado la atención como vectores, debido a su capacidad de condensar ácidos nucleicos para formar partículas que los protegen de la degradación enzimática y facilitan su captación celular. La polietilenimina y el polimetacrilato de N, N-dimetilaminoetilo son los polímeros catiónicos más eficaces para la administración génica. Sin embargo, estos requieren modificaciones químicas específicas para eliminar o disminuir algunas limitaciones tales como su alta citotoxicidad y baja biodegradabilidad. En este artículo se analizan algunas de estas modificaciones, enfocándose en avances recientes en el desarrollo de copolímeros anfifílicos como precursores de nanopartículas usadas como vectores génicos.

SUMMARY During recent years, the use of genetic therapies has taken relevance in the treatment of high-incidence diseases such as cancer. Usually, they are based on the release of genetic material, as plasmids, into the cell nucleus, which corrects a function or induces the production of a deficient protein at the physiological level. To carry out gene therapy, vectors capable of encapsulating the genetic material and guaranteeing its delivery in the target cell nucleus are required. Synthetic cationic polymers have attracted great attention as vectors due to their ability to condense nucleic acids to form particles that protect them from enzymatic degradation and facilitate their cellular uptake. Polyethylenimine and poly (N, N-dimethylaminoethyl methacrylate) are the most effective cationic polymers for gene delivery. However, these polymers require specific chemical modifications to either avoid or diminish their high cytotoxicity and low biodegradability. This review analyzes some of these modifications, focusing on recent advances in the development of amphiphilic copolymers as precursors of nanoparticles used as gene vectors.

Transmembrane mechanism and intracellular trafficking of folic acid-polyethyleneimine carbon dots / 吉林大学学报(医学版)

Objective:To investigate the transport pathway and intracellular distribution of the of fluorescent carbon dots(CDs)synthesized by folic acid and polyethyleneimine(PEI)through the membrane of MC3T3-E1 cells and its effect on the cells,and to clarify the mechanism.Methods:The fluorescent CDs with the function of cell imaging were synthesized by hydrothermal method using folic acid and PEI as the raw materials;MTT assay was applied to screen the best concentration of CDs.The MC3T3-E1 cells were divided into blank control group,folic acid group and CDs group.The biocompatibility of CDs was evaluated by the detection of cell cycle,apoptosis and cellular reactive oxygen species(ROS)level.Nystatin as a kind of caveolae inhibitor and nocodazole as a kind of macropinocytosis inhibitor were used to find out the pathway through which the cells took in the CDs.Using the charcteristic of CDs with blue fluorescence stimulated by ultraviolet ray,the organelle probes were used to observe the distribution of CDs.Results:Compared with blank control group,the cells in different concentrations(100-450 mg·L-1)of CDs groups showed no cytotoxicity at 24 h(P>0.05);at 48 h,the cell proliferation rate was reduced to 68.4% of blank control group when the concentration of CDs reached 350 mg · L -1(P<0.05). Compared with blank control group,the percentages of cells in G0phase and G1phase in CDs group were decreased (P<0.05),and the percentage of cells in S phase was increased(P<0.05);the percentages of cells in G2phase and M phase were increased,but there no was significant differences(P>0.05).Compared with blank control group,the apoptotic rates of the cells in folic acid group and CDs group had no significant differences(P>0.05). Compared with blank control group,the intracellular ROS levels in folic acid group and CDs group were significantly decreased(P<0.05).Compared with blank control group,the uptake amount of CDs in the cells was decreased in nystatin group(P<0.05).The blue fluorescence of CDs overlapped with the red fluorescence of mitochondria under an inverted fluorescence microscope,the blue fluorescence of CDs overlapped with the red fluorescence of lysosomes;they didn't overlap completely with the red fluorescence of the endoplasmic reticulum;the blue fluorescence of CDs overlapped poorly with the red fluorescence of Golgi apparatus.Conclusion:CDs perform well in biocompatibility and they can be distributed to different organelles after taken in by the cells.They can be used as a kind of gene carrier in transgenic therapy.

Synthesis of amphiphilic block copolymer of PLGA-b-(PEI-co-PEG) and characterization of the self-assembled cationic micelles / 南方医科大学学报

<p><b>OBJECTIVE</b>To synthesize a biodegradable and minimally cytotoxic amphiphilic block copolymer of PLGA-b-(PEI-co- PEG) and study its micellization behavior.</p><p><b>METHODS</b>PLGA was synthesized by ring-opening polymerization. The cross-linked copolymer of PEI-co-PEG was synthesized from the low-molecular-weight polyethyleneimine (PEI, 1800 D) and hydrophilic poly(ethylene glycol) (PEG, 2000 D). PLGA-b-(PEI-co-PEG) was synthesized by dehydration condensation reaction of PLGA and water soluble PEI-co-PEG. The biodegradability of PEI-co-PEG was evaluated according to the molecular weight change after incubation at 37 ℃ for different time. The cytotoxicity of PLGA- b-(PEI-co-PEG) and PEI-co-PEG in MCF-7 cells was determined by MTT assay. The cationic PLGA-b-(PEI-co-PEG) micelles were prepared by standard dialysis method. The particle size and Zeta potential of the micelles were measured by a Malvern laser particle size analyzer. Micelle/insulin complexes were prepared by simple mixing method and their morphology were characterized by transmission electron microscopy (TEM). The fluorescence quenching method was used to determine the stability of the micelle/insulin complexes at different salt concentrations.</p><p><b>RESULTS</b>Amphiphilic block copolymer of PLGA-b-(PEI-co-PEG) was successfully synthesized. The half-life of PEI-co-PEG degradation in PBS at 37 ℃ was about 48 h. The 50% cell inhibiting concentration (IC) of PLGA-b-(PEIco- PEG) and PEI-co-PEG in MCF-7 cells were 1375.7 μg/mL and 425.1 μg/mL, respectively. The micelles of PLGA-b-(PEI-co- PEG) (particle size: 99.5±2.61 nm, Zeta potential: 52.9±2.38 mV) were complexed with insulin electrostatic interaction and formed nanoscale micelle/insulin complexes. The dissociation rate of micelle/insulin complexes in 150 mmol/L NaCl solution was 27.6%.</p><p><b>CONCLUSIONS</b>The synthesized PEI-co-PEG shows good degradability . The cytotoxicity of PLGA-b-(PEI-co- PEG) is significantly lower than PEI-co-PEG, and PLGA-b-(PEI-co-PEG) micelle/insulin complexes have good salt- resistant stability in physiological condition.</p>

Transmembrane mechanism and intracellular trafficking of folic acid-polyethyleneimine carbon dots / 吉林大学学报(医学版)

Objective: To investigate the transport pathway and intracellular distribution of the of fluorescent carbon dots (CDs) synthesized by folic acid and polyethyleneimine (PEI) through the membrane of MC3T3-E1 cells and its effect on the cells, and to clarify the mechanism. Methods: The fluorescent CDs with the function of cell imaging were synthesized by hydrothermal method using folic acid and PEI as the raw materials; MTT assay was applied to screen the best concentration of CDs. The MC3T3-E1 cells were divided into blank control group, folic acid grodp and CDs grodp. The biocompatibility of CDs was evaldated by the detection of cell cycle, apoptosis and celldlar reactive oxygen species (ROS) level. Nystatin as a kind of caveolae inhibitor and nocodazole as a kind of macropinocytosis inhibitor were dsed to find od the pathway throdgh which the cells took in the CDs. Using the charcteristic of CDs with bld fldorescence stimdlated by dltraviolet ray, the organelle probes were dsed to observe the distribdtion of CDs. Results: Compared with blank control grodp, the cells in different concentrations (100 - 450 mg · L-1) of CDs grodps showed no cytotoxicity at 24 h (P>0.05); at 48 h, the cell proliferation rate was reddced to 68.4% of blank control grodp when the concentration of CDs reached 350 mg · L-1(P0.05). Compared with blank control grodp, the apoptotic rates of the cells in folic acid grodp and CDs grodp had no significant differences (P>0.05). Compared with blank control grodp, the intracelldlar ROS levels in folic acid grodp and CDs grodp were significantly decreased (P<0.05). Compared with blank control grodp, the dptake amodnt of CDs in the cells was decreased in nystatin grodp (P<0.05). The blde fldorescence of CDs overlapped with the red fldorescence of mitochondria dnder an inverted fldorescence microscope, the blde fldorescence of CDs overlapped with the red fldorescence of lysosomes; they didn't overlap completely with the red fldorescence of the endoplasmic reticdldm; the blde fldorescence of CDs overlapped poorly with the red fldorescence of Golgi apparatds. Conclusion: CDs perform well in biocompatibility and they can be distribdted to different organelles after taken in by the cells. They can be dsed as a kind of gene carrier in transgenic therapy.

Preparation and in vitro evaluation of pH-responsive drug releasing As2O3-loaded PEG-PCL-PEI nanoparticles / 中草药

Objective To prepare and evaluate As2O3 loaded polyethylene glycol-polycaprolactone-polyethyleneimine (PEG-PCL- PEI, PPP) nanoparticles (As2O3-PPP-NPs) in vitro. Methods As2O3-PPP-NPs was prepared by one-step electrostatic loading method using PPP triblock polymer as carrier. The drug loading and entrapment efficiency of the nano-drug were determined by ICP-OES. In vitro drug release property was studied by the dialysis bag method. Hemolytic toxicity of As2O3-PPP-NPs was investigated by UV spectrophotometry. Cytotoxicity of As2O3-PPP-NPs on human cervical cancer (HeLa) and human hepatocellular carcinoma cells (HepG2) was evaluated by MTT assay. Finally, ICP-OES and confocal microscopy was used to investigate the uptake efficiency and uptake mechanism of As2O3-PPP-NPs by HepG2 cells. Results The prepared nano-formulations were spherical and well-dispersed with particle size of 88.7 nm. The encapsulation efficiency and the drug loading rate were (92.75 ± 3.83)% and (4.39 ± 0.26) %, respectively. In vitro release studies showed that As2O3-PPP-NPs had the characteristics of sustained release and low pH responsive drug release, which could achieve specific drug release in the tumor environment. The loading of As2O3 neutralized the positive charge of PPP, and the hemolytic toxicity of the material was reduced. MTT assay showed that the median lethal concentrations (IC50 values) of As2O3-PPP- NPs to HeLa and HepG2 cells were 6.24 μmol/L and 5.85 μmol/L, respectively, which showed strong inhibiting effect on tumor cells. Cellular uptake studies showed that As2O3-PPP-NPs was rapidly taken up by cells due to positively charged surface and featured the lysosomal escaping ability, so the drug could be released in the cytoplasm and exert its anti-tumor effect. Conclusion As2O3-PPP-NPs exhibits significantly sustained and low pH responsive release characteristics, and has the ability to escape from lysosomes. As2O3-PPP-NPs is a potential drug delivery system against solid tumor.

Preparation and characterization of puerarin-loaded polyethyleneimine/sodium alginate nanoparticles / 中草药

Objective To develop the puerarin-loaded polyethyleneimine/alginate nanoparticles (Pur-PEI/ALG-NPs) and investigate their physicochemical properties. Methods The Pur-PEI/ALG-NPs were prepared by electrostatic interaction. The particle size and Zeta potential of nanoparticles were measured by laser light scattering using a Zeta sizer ZEN3600, in vitro release curves for which were studied. The formulation variables were optimized by central composite design-response surface methodology (CCD-RSM) with entrapment efficiency and drug loading as dependent variables. Results An optimal formulation was confirmed as follows: polyethyleneimine concentration was 3.2 mg/mL, alginate concentration was 1.3 mg/mL and the mass ratio of PEI/ALG was 3.75. The resulting nanoparticles exhibited entrapment efficiency of (24.13 ± 1.78)% and drug loading of (11.17 ± 0.71)%, respectively. Zeta potential of nanoparticles was found to be (35.2 ± 0.7) mV, with the average diameter of (118.0 ± 0.4) nm. In vitro release test proved that nanoparticles accelerated the release rate of Pur. Conclusion Pur-PEI/ALG-NPs are prepared successfully with narrow particle size distribution and rich positive charge, which may lay the foundation for further clinical ocular application of Pur.

Co-delivery of siRNA and docetaxel by hyaluronic acid modified redox-sensitive disulfide-crosslinked nanoparticles / 中国药科大学学报

@#The aims of this research were to constitute and evaluate one targeting anticancer co-delivery system for both micro-molecularchemotherapeutic drugs(docetaxel, DTX)and small interfering RNA(siRNA)expressed by COX-2. The nanoparticles composed of poly(D, L-lactide-co-glycolide)(PLGA)bearing disulfide-linkaged reducible polyethyleneimine(PEIss)covered by hyaluronic acid(HA). Meanwhile, HA-PEI-PLGA nanoparticles were prepared as control. Firstly, the solvent evaporation was used to the particles which exhibited a core-shell structure with a uniform size of 150-200 nm. The cumulative drug release in two kinds of PBS media(pH 7. 4 and pH 5. 0)during 72 hours indicated that DTX-loaded nanoparticles had sustained-release effect within 24 hours. The cumulative release of DTX of HRPSP NPs in PBS pH 5. 0 was 10%-25% more than that in PBS pH 7. 4, which demonstrated that favored release of DTX from nanoparticles could be achieved in acidic tumor microenvironment. Then, the highest transfection efficiency was observed after 14-16 h incubation at N/P ratio of 40/1. Following the saturation of CD44 receptor, the mean fluorescence intensity of HRPSP NPs from the cells decreased drastically in the case of saturation with free HA before. However, there existed no significance in the fluorescence of RPSP NPs between the cells with and without saturation with free HA, which indicated the nanoparticles′ targeting potential toward tumor cells. In the Western blot, the relative silencing efficiency of Bcl-2, bax, capase-3 and COX-2 mRNAprotein was calculated. In comparison to the control group, the silence efficiencies of bax and capase-3 were both significantly increased while that of Bcl-2 was evidently reduced, particularly in siCOX-2/HRPSP NPs group(P< 0. 01). The similar results were obtained in the silence efficiency of COX-2 protein in which the COX-2 quantity on mRNA and protein decreased. The results suggest that the nanoparticles could achieve the synergistic effect on the combinatorial delivery of siRNA and lipophilic anti-tumor drugs.

Proteins are transfected into bone marrow mesenchymal stem cells by polyethyleneimine-protein nano-complexes / 中国病理生理杂志

[ ABSTRACT] AIM:To investigate the role of encapsulated protein transfected into human bone marrow mesen-chymal stem cells ( hBMSCs) by polyethyleneimine ( PEI) , and to optimize the best mole ratio of PEI-proteins.METH-ODS:6 groups of DNase I-PEI complexes were constructed and the best mole ratio was explored by laser scattering analy-sis.The appearance of complexes was presented under transmission electron microscope.Meanwhile, 4 groups of construc-ted GFP-PEI complexes were utilized to transfect into the hBMSCs, which were isolated and expand in vitro.The fluores-cence intensity of transfected cells was observed under confocal microscope.In addition, the cytotoxicity of the complexes on the cell proliferation was detected by MTT assay.The activity of the intracellular proteins was testified by aβ-galactosi-dase staining experiment.RESULTS:When the mole ratio of PEI and protein was adjusted to 4∶1, the complex transfec-tion efficiency was the best, and β-galactosidase color test turned blue.CONCLUSION:PEI has the character of encap-sulating various proteins to nano-complexes.The proteins transfected into bone marrow mesenchymal stem cells are con-firmed to have functional activity.As a protein carrier, PEI is of high efficiency and low toxicity, thus providing a new way for stem cell reprogramming.

Stem Cell Tracking with Amphiphilic Polyethyleneimine Modified Quantum Dots as Functional Optic Probes / 华中科技大学学报(医学版)

Objective Stem cell therapy has been extensively used in clinical practice. However ,the methods available are unable to non‐invasively detect the distribution of cells in vivo. This study was aimed to establish a novel molecular imaging probe for stem cell labeling ,which would monitor cells via fluorescence imaging. Methods 1‐iodododecane was used to modify polyethyleneimine (PEI) to form amphiphilic macromolecules. These macromolecules encapsulated the hydrophobic quantum dots by self‐assembly to form imaging probes. Results Strong fluorescence signals of the probe occurred at 630 nm ,and the probe could be effectively endocyted by mesenchyme stem cells. In vivo imaging showed that significant optic signals occurred in probe‐labeled mesenchyme stem cells compared with the control cells (blank group:1.47e8 [p/s/cm2/sr]/[μW/cm2 ];test group:2.78e8 [p/s/cm2/sr]/[μW/cm2 ]). Conclusion The nanoprobes have good optic imaging effects ,and can be used to la‐bel cells.

Polyethyleneimine as targeted gene vectors:a review / 国际药学研究杂志

Currently, polyethylenimine(PEI) is one of the most promising non-viral gene delivery vectors. However, high relative molecular mass PEI has obvious toxicity and is short of targeting or specificity to cells or tissues. As we know, targeting or specificity is the key property of ideal gene delivery systems. Therefore, PEI should be modified to become a gene vector with targeting and low toxicity. Up to now, investgations on modification of PEI for targeting effect mainly include:1.modification with endogenous ligands such as transferrin(Tf),RGD peptide, etc;2.modification with carbohydrate such as galactose,etc;3.modification with specific antibody. Of these, the specific antibody-directed PEI is anticipated to be one of promising and distinctive targeting gene delivery carriers. The present paper summarises literature on PEI as targeted gene delivery vectors.

Polyethyleneimine as targeted gene vectors: A review / 国际药学研究杂志

Currently, polyethylenimine(PEI) is one of the most promising non-viral gene delivery vectors. However, high relative molecular mass PEI has obvious toxicity and is short of targeting or specificity to cells or tissues. As we know targeting or specificity is the key property of ideal gene delivery systems. Therefore, PEI should be modified to become a gene vector with targeting and low toxicity. Up to now investgations on modification of PEI for targeting effect mainly include:1.modification with endogenous ligands such as transferrin Tf RGD peptide etc 2.modification with carbohydrate such as galactose etc 3.modification with specific antibody. Of these, the specific antibody-directed PEI is anticipated to be one of promising and distinctive targeting gene delivery carriers. The present paper summarises literature on PEI as targeted gene delivery vectors.

Construction and characterization of mitochondria-targeted TPP-PEI-LND / 中国药科大学学报

@#The mitochondria-targeted TPP-PEI-LND was synthesized by mitochondria-targeted ligand triphenylphosphine(TPP)and therapeutic drug lonidamine(LND)conjugated to low molecular weight branched polyethyleneimine(PEI). TPP-PEI-LND was verified using 1H NMR; in vitro release was determined by the dialysis. Besides, the cytotoxicity and mitochondria-targeted potential of TPP-PEI-LND were investigated in HeLa cells. The results showed that TPP-PEI-LND was successfully synthesized and it exhibited the feature of extended-release. Hence, TPP-PEI-LND could deliver LND to mitochondria, resulting in significantly enhanced efficacy of LND.

A Hydrogen Peroxide Sensor Based on Pt@Au Nanoparticles Loading to Polyethyleneimine Functionalized Carbon Nanotubes / 分析化学

A novel hydrogen peroxide sensor was fabricated by the seed-mediated growth method. First, polyethyleneimine(PEI) functionalized multiwalled carbon nanotubes(MWNTs) were used as growth scaffold on the glass carbon electrode ( GCE). Then, Au nanoparticles were electrodeposited uniformly as seeds. Finally, Pt nanoparticles ( PtNPs ) grew on Au nanoparticles to form Pt @ Au core-shell structure nanocomposite. A new type of electrochemical sensor based on Pt @ Au / PEI-MWNTs nanocomposites for detection of hydrogen peroxide was developed, and the designed Pt@ Au / PEI-MWNTs/ GCE was characterized by electrochemical methods and field emission scanning electron microscopy (FESEM). The Differential pulse experimental results showed that the modified electrode exhibited excellent electrocatalytic activity towards the reduction of H2 O2 with the wide linear range from 9. 2 ×10-8 mol/ L to 1. 3 ×10-3 mol/ L. The correlation coefficient was 0. 9994 and the low detection limit was 3. 1×10-8 mol/ L at the signal-to-noise of 3.

Preparation and properties of chitosan/β-glycerophosphate thermosensitive hydrogel containing amino-carbon nanotubes / 中国药学杂志

OBJECTIVE: To synthesis chitosan/β-glycerophosphate (CS/β-GP) thermosensitive hydrogel containing multi-walled carbon nanotubes-polyethyleneimine (MWCNTs-PEI) complexes and to lay a foundation for further research of dual slow-release delivery system. METHODS: Chitosan thermosensitive hydrogel containing MWCNTs-PEI was prepared by MWCNTs-PEI dispersed to the chitosan thermosensitive hydrogel. As the indicator of the gelling time, the experiment studied the effect of β-GP concentration, pH, temperature and MWCNTs-PEI composite quality on the thermosensitive chitosan hydrogel, and then it was charactered by using transmission electron microscopy (SEM), infrared spectrometer(IR), and initially investigated in vivo compatibility. RESULTS: The dynamic rheology method investigated the gelling temperature were about 37.0°C. Within a certain range, the gelling time of thermosensitive chitosan hydrogel was shortened with the increase of concentration of β-GP, pH, temperature, and the quality of MWCNTs-PEI complexes, and they could be transformed into the hydrogel in vivo. The addition of MWCNTs-PEI complex didn't react chemically with the thermosensitive chitosan hydrogel and significantly make the holes of the chitosan thermosensitive hydrogel smaller by SEM and FT-IR, eventually leading to the swelling rate and the corrosional ratio decrease. CONCLUSION: Chitosan/β-glycerophosphate thermosensitive hydrogel containing amino-carbon nanotubes has a rapid gelation and good temperature-sensitivity, which can serve as a good double sustained-release carrier.

Characteristics of Penicillin G Acylase Immobilized onto Iron Oxide Nanoparticles.

Penicillin G acylase was immobilized onto iron oxide nanoparticles coated with polyethyleneimine and then cross linked with glutaraldehyde solution. The FTIR spectrum of immobilized enzyme showed peak at 1648cm-1 which can be attributed to the C=N bonds of Schiff’s base linkage formed between glutaraldehyde and amino group of penicillin G acylase. By considering the FTIR spectrum of nano particle coated with polyethyleneimine, adsorption of penicillin G acylase has taken place and then glutaraldehyde cross linked enzyme onto activated support. Catalytic properties of nano penicillin G acylase were improved upon immobilization as compared to its free counterpart. The optimal pH and temperature were determined to be 7.0, 10.0, 50 and 75ºC for free and immobilized penicillin G acylase, respectively. Thermal stabilities of both nano and free penicillin G acylase were studied .The Km value of immobilized nanozyme was calculated from Lineweaver Burck plot to be 0.23 μM while that of free penicillin G acylase was 0.28μM. In this way nano penicillin G acylase with improved catalytic properties was developed as compared to its soluble counterpart.

Enhanced gene transfection to HepG2 cells mediated by self-made cationic nanobubbles / 中华超声影像学杂志

Objective To observe self-made cationic nanobubbles as non-viral gene carrier to transfer green fluorescent protein reporter gene into HepG2 cell in vitro.Methods Cationic nanobubbles(PNB) were prepared by sonicating liposomes、polyethylenimine and perfluoropropan.The surface potential and the size of nanobubbles were assessed by laser particle analyzer.HepG2 cells were incubated with DNA,nanobubbles with or without ultrasound exposure.The transfection efficiency was evaluated by flow cytometer and the cell viability by cell counting Kit-8.Results The mean diameter of PNB was (834.57 ± 6.4) nm and the surface charge was (4.15± 0.98)mV.The PNB-DNA complexes,which blocked by the Agarose gel electrophoresis,could effectively transfer HepG2 cells,and the ultrasound exposure could enhance the transfection efficiency further significantly (P ＜ 0.05).Conclusions The new PNB could effectively combine with pDNA to enhance gene delivery and ultrasound exposure could improve its efficiency further in HepG2 cell in vitro.