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Zhang C.,CAS Institute of Microbiology | Gao S.,CAS Institute of Microbiology | Jiang W.,CAS Institute of Microbiology | Lin S.,CAS Beijing National Laboratory for Molecular | And 5 more authors.
Biomaterials | Year: 2010

Targeted gene delivery systems have attracted great attention due to their potential in directing the therapeutic genes to the target cells. However, due to their low efficiency, most of the successful applications of polymeric vectors have been focused on genes which can achieve robust expression. Minicircle DNA (mcDNA) is a powerful candidate in terms of improving gene expression and prolonging the lifespan of gene expression. In this study, we have combined folate/poly(ethylene glycol) modified polyethylenimine and mcDNA as a new tumor gene delivery system. We found that folate-labeled polyplexes were homogenous, with a size ranging from 60 to 85 nm. mcDNA increased folate-labeled vector based gene expression 2-8 fold in folate receptor-positive cells. Results of folic acid competition assay indicated that mcDNA mediated by folate-labeled vector were internalized into cells through receptor-mediated endocytosis. The investigation of the endocytosis pathway of the polyplexes showed that a large portion of them escaped from endo/lysosome and the polyplexes were associated before being separated in the nucleus. Furthermore, in vivo optical imaging and luciferase assays demonstrated that systemic delivery of the folate-labeled polyplexes resulted in preferential accumulation of transgenes in folate receptor-positive tumors, and mcDNA mediated approach achieved 2.3 fold higher gene expressions in tumors than conventional plasmid. Cytotoxicity assays showed that PEG-shielding of the polyplexes reduced the toxicity of PEI. © 2010 Elsevier Ltd.


Zhai X.,Tianjin University | Zhang P.,Tianjin University | Zhang P.,Case Western Reserve University | Liu C.,Tianjin University | And 5 more authors.
Chemical Communications | Year: 2012

Carbon nanodots (CDs) with a low cytotoxicity have been synthesized by one-step microwave-assisted pyrolysis of citric acid in the presence of various amine molecules. The primary amine molecules have been confirmed to serve dual roles as N-doping precursors and surface passivation agents, both of which considerably enhanced the fluorescence of the CDs. © 2012 The Royal Society of Chemistry.


Tian F.,China Institute of Medical Equipment | He C.N.,Tianjin University
Materials Chemistry and Physics | Year: 2010

The synthesis of carbon nanospheres (CNSs) by chemical vapor deposition (CVD) of methane on catalyst of Ni-Al composite powders was reported. The influence factors on the growth morphology of CNSs, such as reaction temperature, reaction time and different carrier gases concerning hydrogen, nitrogen as well as no carrier gas were investigated using transmission electron microscope. The results showed that the reaction temperature had great effect on the structure of CNSs, higher temperature led to high-crystallized CNSs with high purity. The reaction time brought no significant influence to the structure of CNSs, but the average diameter of the CNSs was obviously increased with prolonging the reaction time. Relatively pure CNSs could be obtained with hydrogen as the carrier gas but with poor product rate compared with the CNSs with no carrier gas. Proper amount of CNSs with pure characteristic could be obtained with nitrogen as the carrier gas. Finally, a growth mechanism of dissolution-precipitation-diffusion is proposed for elucidating the growth process of general CNSs. © 2010 Elsevier B.V. All rights reserved.


Li F.,China Institute of Medical Equipment | Liu C.,China Institute of Medical Equipment | Yang J.,China Institute of Medical Equipment | Wang Z.,China Institute of Medical Equipment | And 2 more authors.
RSC Advances | Year: 2014

Carbon dots (CDs) with quantum yield up to 83% have been synthesized with a Mg/N double doping fluorescence-enhanced strategy. Besides N-mediated surface passivation by ethylenediamine, the Mg-citric acid chelate played the roles of introducing Mg and preserving the carboxyl group, both greatly contributing to the photoluminescence enhancement of the final CDs. Importantly, the N- and Mg-doping functioned in concert without mutual influence.


Wang Q.-S.,Tianjin University of Traditional Chinese Medicine | Wang Q.-S.,China Institute of Medical Equipment | Tian J.-S.,Tianjin University of Traditional Chinese Medicine | Tian J.-S.,Shanxi University | And 2 more authors.
Neuroscience | Year: 2014

Genipin, an important bioactive component from Gardenia jasminoides Eills, was demonstrated to possess antidepressant-like effects in a previous study. However, the molecular mechanism of antidepressant-like effects on genipin was not clear. The present study aimed to investigate the possible mechanism of antidepressant-like effects on genipin with a chronic unpredictable mild stress (CUMS)-induced depression model in rats. In CUMS-induced depressive rats, bodyweight and 1% sucrose consumption decreased significantly compared with the normal control group. Furthermore, these changes could be significantly reversed by genipin application. The levels of 5-hydroxytryptamine (5-HT), norepinephrine (NE) in the hippocampus decreased and the level of 5-hydroxyindole acetic acid (5-HIAA) increased in the CUMS-induced depressive rats. However, pre-treatments with genipin significantly increased the levels of 5-HT, NE and decreased the level of 5-HIAA in the hippocampus. The concentration of cAMP in the hippocampus was increased by genipin compared to the CUMS-exposed model group. The mRNA expressions of 5-hydroxytryptamine 1A receptor (5-HT1AR), cAMP response element binding protein (CREB) and brain-derived neurotrophic factor (BDNF) in rats were decreased exposed to CUMS, which were reversed by genipin-treated rats exposed to CUMS. Compared to the CUMS-exposed model group, the mRNA expression of 5-hydroxytryptamine 2A receptor (5-HT2AR) was decreased significantly by genipin-treated rats. The mRNA and protein expression of CREB, BDNF were increased in genipin-treated rats compared to the CUMS-exposed model group. Moreover, the levels of corticosterone in serum were decreased by genipin-treated compared to the CUMS-exposed model group. These results suggest that the possible mechanism of antidepressant-like effects on genipin, at least in one part, resulted from monoaminergic neurotransmitter system and the potential dysfunctional regulation of the post-receptor signaling pathway, which particularly affected the 5-HT1AR, 5-HT2AR and BDNF levels in the hippocampus. © 2014 IBRO.


Liu C.,Tianjin University | Liu C.,China Institute of Medical Equipment | Zhang P.,Tianjin University | Zhai X.,Tianjin University | And 7 more authors.
Biomaterials | Year: 2012

Polyethylenimine (PEI) functionalized carbon dots (CD-PEI) were fabricated by one-step microwave assisted pyrolysis of glycerol and branched PEI25k mixture where the formation of carbon nanoparticles and the surface passivation were accomplished simultaneously. In this hybrid C-dot, PEI molecule played two key roles in the system - as a nitrogen-rich compound to passivate surface to enhance the fluorescence and as a polyelectrolyte to condense DNA. This CD-PEI was shown to be water soluble and emit stable bright multicolor fluorescence relying on excitation wavelength. The DNA condensation capability and cytotoxicity of CD-PEI could be regulated by pyrolysis time possibly due to the somewhat destruction of PEI during the formation of carbon dots. CD-PEI obtained at an appropriate pyrolysis time exhibited lower toxicity, higher or comparable gene expression of plasmid DNA in COS-7 cells and HepG2 cells relative to control PEI25k. Intriguingly, the CD-PEIs internalized into cells displayed tunable fluorescent emission under varying excitation wavelength, suggesting the potential application of CD-PEI in gene delivery and bioimaging. © 2012 Elsevier Ltd.


Liu C.,Tianjin University | Liu C.,China Institute of Medical Equipment | Zhang P.,Tianjin University | Tian F.,China Institute of Medical Equipment | And 3 more authors.
Journal of Materials Chemistry | Year: 2011

Strong photoluminescent carbon nanodots (C-dots) were synthesized by one-step microwave assisted pyrolysis of glycerol in the presence of 4,7,10-trioxa-1,13-tridecanediamine (TTDDA). The formation and surface passivation of C-dots were accomplished simultaneously. The obtained C-dots exhibited excellent biocompatibility and preeminent multicolor photoluminescent properties for bioimaging. © 2011 The Royal Society of Chemistry.


Zhang X.-Z.,China Institute of Medical Equipment
Yiyong Shengwu Lixue/Journal of Medical Biomechanics | Year: 2016

Bone growth, development and maintenance, which become multidisciplinary with the rapid development of biomechanics, tissue engineering and cell biology, are intimately linked with bone remodeling. Mechanobiology has become an important method to study bone remodeling. This article summarizes related skeletal mechanobiology researches in recent years to provide theoretical basis for bone remodeling, bone tissue engineering and clinical treatments of related orthopedic disorders. Copyright © 2016 by the Editorial Board of Journal of Medical Biomechanics.


Tian F.,China Institute of Medical Equipment | He C.N.,China Institute of Medical Equipment
Materials Research Bulletin | Year: 2011

Carbon nanotube-alumina hybrid reinforced high density polyethylene (HDPE) matrix composites were prepared by melt processing technique. Microstructure studies verified that the nanotubes consisting of well-crystallized graphite formed a network structure with Al2O3 in the hybrid, which was homogeneously dispersed in the HDPE matrix composites. Mechanical measurements revealed that 5% addition of nanotube-alumina hybrid results in 100.8% and 65.7% simultaneous increases in Young's modulus and tensile strength, respectively. Fracture surface showed homogenous dispersion of nanotubes and Al2O3 in the HDPE matrix and presence of interlocking like phenomena between hybrid and HDPE matrix, which might contribute to the effective reinforcement of the HDPE composites. © 2011 Elsevier Ltd. All rights reserved.


Zhang X.-Z.,China Institute of Medical Equipment
Yiyong Shengwu Lixue/Journal of Medical Biomechanics | Year: 2010

Tissue engineering is one of the most promising subjects, which has broad application prospects in the fields of regenerative medicine and human health care. According to the papers published in this current issue about scaffold material preparation and mechanical environment affection to cells during the construction process of tissue engineering, this paper describes the current status and progress of tissue engineering research at home and abroad, indicating that tissue engineering research is developing to a deeper and wider field.

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