Ultraviolet sensing based on an in-fiber ZnO microwire constructed Mach-Zehnder interferometer.

We propose a Mach-Zehnder interferometer based on an in-fiber ZnO microwire structure for ultraviolet sensing. The device undergoes femtosecond laser micromachining and chemical etching on a single-mode optical fiber initially, creating a microgroove that extends to half of the core's depth, into which a single ZnO microwire is transferred. The ZnO microwire and the remaining core are used as the sensing arm and the reference arm, respectively, forming a Mach-Zehnder interferometer. To enhance the stability and the sensitivity, ZnO nanoparticles are filled into the microgroove after the ZnO microwire is transferred. The fabricated device exhibits a sensitivity of 0.86 nm/(W·cm-2) for ultraviolet sensing, along with a response time of 115 ns (rise time) and 133 µs (decay time), respectively. The proposed sensor exhibits good ultraviolet sensitivity, offering a novel approach for ultraviolet sensing technology.

A D-Shaped Polymer Optical Fiber Surface Plasmon Resonance Biosensor for Breast Cancer Detection Applications.

Fiber-optic biosensors have garnered significant attention and witnessed rapid development in recent years owing to their remarkable attributes such as high sensitivity, immunity to electromagnetic interference, and real-time monitoring. They have emerged as a potential tool in the realm of biomarker detection for low-concentration and small molecules. In this paper, a portable and cost-effective optical fiber biosensor based on surface plasmon resonance for the early detection of breast cancer is demonstrated. By utilizing the aptamer human epidermal growth factor receptor 2 (HER2) as a specific biomarker for breast cancer, the presence of the HER2 protein can be detected through an antigen-antibody binding technique. The detection method was accomplished by modifying a layer of HER2 aptamer on the flat surface of a gold-coated D-shaped polymer optical fiber (core/cladding diameter 120/490 µm), of which the residual thickness after side-polishing was about 245 µm, the thickness of the coated gold layer was 50 nm, and the initial wavelength in pure water was around 1200 nm. For low-concentration detection of the HER2 protein, the device exhibited a wavelength shift of ~1.37 nm with a concentration of 1 µg/mL (e.g., 5.5 nM), which corresponded to a limit of detection of ~5.28 nM. Notably, the response time of the biosensor was measured to be as fast as 5 s. The proposed biosensor exhibits the potential for early detection of HER2 protein in initial cancer serum and offers a pathway to early prevention of breast cancer.

Ghrelin attenuates sepsis-induced acute lung injury by inhibiting the NF-κB, iNOS, and Akt signaling in alveolar macrophages.

Ghrelin has proven to be protective against sepsis-induced acute lung injury (ALI) via anti-inflammatory effects. However, its mechanisms remain poorly understood. Alveolar macrophages (AMs) play a key role in mediating inflammatory responses during sepsis-induced ALI by secretion of cytokines and chemokines. This study was undertaken to investigate whether ghrelin suppresses inflammatory effects of AMs and therefore may help to attenuate sepsis-induced ALI. A sepsis model in rats was achieved using cecal ligation and puncture. Ghrelin treatment markedly improved histopathological changes in the lungs and reduced pulmonary inflammation in septic rats. NF-κB translocation and p-Akt and inducible nitric oxide synthase (iNOS) activities in AMs from septic rats were suppressed by ghrelin. In vitro data indicated that ghrelin decreased the levels of LPS-induced IL-1ß, TNF-α, and IL-6, NF-κB translocation, and iNOS and Akt activities of AMs. Furthermore, the NF-κB/iNOS pathway or Akt signaling was positively correlated with LPS-induced inflammatory production of AMs in vitro. In conclusion, ghrelin exerts a protective role against sepsis-induced ALI probably by reducing the production of inflammatory cytokines from AMs via inhibition of the NF-κB/iNOS pathway or Akt signaling.

miR-26a prevents neural stem cells from apoptosis via ß-catenin signaling pathway in cardiac arrest-induced brain damage.

Neural stem cells (NSCs) transplantation is one of the most promising strategies for the treatment of CA-induced brain damage. The transplanted NSCs could differentiate into new neuron and replace the damaged one. However, the poor survival of NSCs in severe hypoxic condition is the limiting step to make the best use of this kind of therapy. In the present study, we investigated whether the overexpression of miR-26a improves the survival of NSCs in hypoxic environment in vitro and in vivo. In vitro hypoxia injury model is established in NSCs by CoCl2 treatment, and in vivo cardiac arrest (CA) model is established in Sprague-Dawley (SD) rats. Quantitative real-time polymerase chain reaction is used to detect the mRNA level and Western blot is used to examine the protein level of indicated genes. TUNEL staining and flow cytometry are applied to evaluate apoptosis. Dual-luciferase reporter assay is utilized to analyze the target gene of miR-26a. The expression of miR-26a is reduced in both in vitro and in vivo hypoxic model. MiR-26a directly targets 3'-UTR of glycogen synthase kinase 3ß (GSK-3ß), resulting in increased ß-catenin expression and decreased apoptosis of NSCs. Overexpression of miR-26a in transplanted NSCs improves the survival of NSCs and neurological function in CA rats. MiR-26a prevents NSCs from apoptosis by activating ß-catenin signaling pathway in CA-induced brain damage model. Modulating miR-26a expression could be a potential strategy to attenuate brain damage induced by CA.

[Effect of poly (L-lysine) modified silk fibroin film on the growth and differentiation of neural stem cells].

In order to provide a basic theory for the materials of repairing central nervous system injury, we have studied the growth and differentiation of neural stem cells (NSCs) on poly (L-lysine) modified silk fibroin film. First, we used poly (L-lysine) to modify silk fibroin film and confirmed by UV-vis and 1H NMR spectra. Then NSCs were isolated and seeded on the silk fibroin film (Silk group), poly (L-lysine) (PLL group) and poly (L-lysine) modified Silk fibroin film (Silk-PIL group). The proliferation of NSCs was evaluated by Cell Counting Kit-8 (CCK-8) assay on days 1, 3, 5 and 7 after seeding. Immunofluorescence was used to analyze the differentiation of NSCs at the 7th day. The levels of apoptosis were detected by Western blotting and TUNEL. The mRNA level of brain derived neurotrophic factor (BDNF) was identified by real-time PCR. UV-vis and 1H NMR spectra confirmed that poly (L-lysine) was successfully grafted onto the silk fibroin film. From the 3rd day after seeding to the 7th day, the CCK-8 test showed that proliferation rate of NSCs in the Silk-PIL was significantly higher than Silk group (P<0.05) but had no significant difference compared with PLL group (P>0.05). Immunofluorescence staining displayed that more NSCs in Silk-PIL group were differentiated into neuron compared with Silk group (P<0.05), however, there was no significant difference compared with PLL group (P>0.05). The number of NSCs differentiated into astrocytes was not significantly different between the three groups. Western blotting and TUNEL test presented that the degree of apoptosis of NSCs in the Silk-PIL group was significantly lower than Silk group (P<0.05). RT-PCR exhibited that mRNA level of brain derived neurotrophic factor (BDNF) of NSCs was higher in Silk-PIL group compared with Silk group (P<0.05) but had no significant difference compared with PLL group (P>0.05). Thus, poly (L-lysine) modified silk fibroin film could promote the proliferation of NSCs and reduce NSCs apoptosis. Furthermore, it also can enhance the differentiation of NSCs into neurons. It is expected to become a new type of tissue engineering scaffold carrying NSCs to repair central nervous system injury.

Effects of Ghrelin on iNOS-Derived NO Promoted LPS-Induced Pulmonary Alveolar Epithelial A549 Cells Apoptosis.

BACKGROUND/AIMS: In the process of abnormal apoptosis of pulmonary alveolar type II epithelial A549 cells in acute respiratory distress syndrome (ARDS), inducible nitric oxide synthase (iNOS) activity in the lung, nitric oxide (NO) production, and the level of protein S-nitrosylation were increased. However, the role of excessive NO production in sepsis-induced ARDS is controversial. Additionally, ghrelin is a growth hormone that exerts an inhibitory role in cell apoptosis. We examined the effect of NO and S-nitrosylation on apoptosis of A549 cells induced by Lipopolysaccharide (LPS) and molecular mechanism underlying the anti-apoptotic effect of ghrelin in this process. METHODS: Flow cytometry and qPCR were used to detect lentiviral infection efficiency and iNOS gene level, respectively. Extracellular and intracellular NO levels were observed by Griess assay kit and DAF-FM DA. Mitochondrial transmembrane potential, apoptosis rate and SNO levels were determined by flow cytometry, Biotin-Switch method and immunofluoresence staining. The expression of iNOS, apoptotic proteins and JNK were assessed by immunoblot analysis. RESULTS: The results showed about two times increase in iNOS expression and intracellular NO levels response to LPS exposure at 24 hours (P< 0.05), while not in extracellular NO levels. NO donors, S-nitroso-N-acetylpenicillamine (SNAP) significantly raised (36.7%, P< 0.05; 38.4%, P< 0.05; 41.8%, P< 0.05) extracellular NO levels without influencing the intracellular NO levels. LPS increased the apoptosis rate (42.4%±2.6% vs 2.8%±1%, P< 0.05) of A549 accompanied by increased Bax levels and decreased Bcl-2 levels through activating JNK signaling, which was reversed when we diminished the iNOS expression in A549 cells using lentiviral vectors encoding iNOS shRNA in the presence of LPS (24.8%±3.8% vs 42.4%±2.6%, P< 0.05). However, the apoptosis rate was increased when SNAP was added (38.8%±1.3% vs 24.8%±3.8%, P< 0.05). Furthermore, we investigated whether ghrelin exert a protective role against LPS-induced apoptosis and the potential mechanism involved in. Ghrelin alone appeared to decrease iNOS expression (32.3%, P< 0.05; 42.3%, P< 0.05), which showed no signifiant difference between LPS+ghrelin group and LPS group. However, this study showed that ghrelin decreased the intracellular NO production (38.9%, P< 0.05), protein S-nitrosylation levels (33.5%, P< 0.05), Bax protein expression (70.2%, P< 0.05), whereas increasing Bcl-2 protein expression (14.1%, P< 0.05) and mitochondrial transmembrane potential (∆ΨM) (20.7%, P< 0.05) in the presence of LPS. CONCLUSION: The data suggested that NO derived from iNOS induced by LPS stimulation exerts an important role in promoting apoptosis of A549 cells, and ghrelin abolished intracellular NO production and protein S-nitrosylation levels, abrogating the apoptosis of A549 cells partly through inhibiting mitochondrial-dependent pathways.

Rare coding variants in MAPK7 predispose to adolescent idiopathic scoliosis.

Adolescent idiopathic scoliosis (AIS) is a complex genetic disorder characterized by three-dimensional spinal curvatures, affecting 2%-3% of school age children, yet the causes underlying AIS are not well understood. Here, we first conducted a whole-exome sequencing and linkage analysis on a three-generation Chinese family with autosomal-dominant (AD) AIS, and then performed targeted sequencing in a discovery cohort comprising 20 AD AIS families and 86 simplex patients, and finally identified three disease-associated missense variants (c.886G> A, c.1943C> T, and c.1760C> T) in the MAPK7 gene (encoding mitogen-activated protein kinase 7). Genotyping of the three rare variants in a Chinese replication cohort comprising 1,038 simplex patients and 1,841 controls showed that their combined allele frequency was significantly over-represented in patients as compared with controls (2.0% [41/2,076] vs. 0.7% [27/3,682]; odds ratio = 2.7; P = 2.8 × 10-5 ). In vitro, we demonstrated that the three MAPK7 mutants disrupted nuclear translocation in cellular models, which is necessary for the normal function of MAPK7. In vivo, we also conducted CRISPR/Cas9-mediated deletion of mapk7 in zebrafish recapitulating the characteristic phenotype of idiopathic scoliosis. Taken together, our findings suggest that rare coding variants in MAPK7 predispose to AIS, providing clues to understanding the mechanisms of AIS.

Low-Temperature Fusible Silver Micro/Nanodendrites-Based Electrically Conductive Composites for Next-Generation Printed Fuse-Links.

We systematically investigate the long-neglected low-temperature fusing behavior of silver micro/nanodendrites and demonstrate the feasibility of employing this intriguing property for the printed electronics application, i.e., printed fuse-links. Fuse-links have experienced insignificant changes since they were invented in the 1890s. By introducing silver micro/nanodendrites-based electrically conductive composites (ECCs) as a printed fusible element, coupled with the state-of-the-art printed electronics technology, key performance characteristics of a fuse-link are dramatically improved as compared with the commercially available counterparts, including an expedient fabrication process, lower available rated current (40% of the minimum value of Littelfuse 467 series fuses), shorter response time (only 3.35% of the Littelfuse 2920L030 at 1.5 times of the rated current), milder surface temperature rise (16.89 °C lower than FGMB) and voltage drop (only 24.26% of FGMB) in normal operations, easier to mass produce, and more flexible in product design. This technology may inspire the development of future printed electronic components.

Ghrelin ameliorates the human alveolar epithelial A549 cell apoptosis induced by lipopolysaccharide.

Ghrelin is a gastric acyl-peptide that plays an inhibitory role in cell apoptosis. Herein we investigate the protective effects of ghrelin in LPS-induced apoptosis of human alveolar epithelial A549 cells, along with the possible molecular mechanisms. LPS exposure impaired cell viability and increased apoptosis of A549 cells significantly in concentration- and time-dependent manners embodied in increased Bax and cleaved caspase-3 production, coupled with decreased Bcl-2 levels. Simultaneously, LPS remarkably decreased the expression of phosphatidylinositol 3 kinase/protein kinase B (PI3K/Akt) and extracellular signal-regulated kinas (ERK) in A549 cells. However, ghrelin'pretreatment ameliorated LPS-caused alterations in the ratio of Bax/Bcl-2 and cleaved caspase-3 expression, whereas activated the PI3K/Akt and ERK signaling. These results demonstrate that ghrelin lightens LPS-induced apoptosis of human alveolar epithelial cells partly through activating the PI3K/Akt and ERK pathway and thereby might benefit alleviating septic ALI.

Apatinib inhibits VEGF signaling and promotes apoptosis in intrahepatic cholangiocarcinoma.

Tumor cells co-express vascular endothelial growth factor (VEGF) and VEGF receptors (VEGFRs) that interact each other to support a self-sustainable cell growth. So far, this autocrine VEGF loop is not reported in human intrahepatic cholangiocarcinoma (ICC). Apatinib is a highly selective VEGFR2 inhibitor, but its effects on ICC have not been investigated. In this study, we reported that VEGF and phosphorylated VEGFR2 were expressed at a significantly high level in ICC patient tissues (P<0.05). In vitro, treating ICC cell lines RBE and SSP25 with recombinant human VEGF (rhVEGF) induced phosphorylation of VEGFR1 (pVEGFR1) and VEGFR2 (pVEGFR2); however, only the VEGFR2 played a role in the anti-apoptotic cell growth through activating a PI3K-AKT-mTOR anti-apoptotic signaling pathway which generated more VEGF to enter this autocrine loop. Apatinib inhibited the anti-apoptosis induced by VEGF signaling, and promoted cell death in vitro. In addition, Apatinib treatment delayed xenograft tumor growth in vivo. In conclusion, the autocrine VEGF/VEGFR2 signaling promotes ICC cell survival. Apatinib inhibits anti-apoptotic cell growth through suppressing the autocrine VEGF signaling, supporting a potential role for using Apatinib in the treatment of ICC.

Curcumin Ameliorates Reserpine-Induced Gastrointestinal Mucosal Lesions Through Inhibiting IκB-α/NF-κB Pathway and Regulating Expression of Vasoactive Intestinal Peptide and Gastrin in Rats.

The objective of our study was to investigate whether curcumin protects against reserpine-induced gastrointestinal mucosal lesions (GMLs) in rats and to explore the mechanism of curcumin's action. Sprague-Dawley rats were randomly divided into four groups: control group, reserpine-treated group, reserpine treatment group with curcumin at high dose (200 mg/kg), and reserpine treatment group with curcumin at low dose (100 mg/kg). Rats in reserpine-treated group were induced by intraperitoneally administered reserpine (0.5 mg/kg) for 28 days. TUNEL staining and hematoxylin and eosin staining were used to evaluate the apoptotic cells and morphologic changes. In addition, to explore the mechanism of curcumin in protecting GMLs, we used serum of experimental rats to assess the level of vasoactive intestinal peptide (VIP), gastrin, interleukin-6, interleukin-10, tumor necrosis factor-α and interferon-γ by ELISA and radioimmunoassay. The protein levels of NF-κB, p-IκB-α, IκB-α, Bcl-2, Bax, and cleaved-caspase-3 were examined by western blot analysis. Data were analyzed with SPSS 19.0 software package. Curcumin treatment prevented tissue damage and cell death in the reserpine-treated rats and effectively decreased inflammatory response and balanced the expression of VIP and gastrin in the reserpine-treated rats. NF-κB, p-IκB-α, Bax, and cleaved-caspase-3 were increased in the reserpine group, but the curcumin high-dose group inhibited them. Curcumin can target the IκB-α/NF-κB pathway to inhibit inflammatory response and regulate the level of VIP and gastrin in reserpine-induced GML rats.

Lingo-1 shRNA and Notch signaling inhibitor DAPT promote differentiation of neural stem/progenitor cells into neurons.

Determination of the exogenous factors that regulate differentiation of neural stem/progenitor cells into neurons, oligodendrocytes and astrocytes is an important step in the clinical therapy of spinal cord injury (SCI). The Notch pathway inhibits the differentiation of neural stem/progenitor cells and Lingo-1 is a strong negative regulator for myelination and axon growth. While Lingo-1 shRNA and N-[N-(3, 5-difluorophenacetyl)-1-alanyl]-S-Phenylglycinet-butylester (DAPT), a Notch pathway inhibitor, have been used separately to help repair SCI, the results have been unsatisfactory. Here we investigated and elucidated the preliminary mechanism for the effect of Lingo-1 shRNA and DAPT on neural stem/progenitor cells differentiation. We found that neural stem/progenitor cells from E14 rat embryos expressed Nestin, Sox-2 and Lingo-1, and we optimized the transduction of neural stem/progenitor cells using lentiviral vectors encoding Lingo-1 shRNA. The addition of DAPT decreased the expression of Notch intracellular domain (NICD) as well as the downstream genes Hes1 and Hes5. Expression of NeuN, CNPase and GFAP in DAPT treated cells and expression of NeuN in Lingo-1 shRNA treated cells confirmed differentiation of neural stem/progenitor cells into neurons, oligodendrocytes and astrocytes. These results revealed that while Lingo-1 shRNA and Notch signaling inhibitor DAPT both promoted differentiation of neural stem cells into neurons, only DAPT was capable of driving neural stem/progenitor cells differentiation into oligodendrocytes and astrocytes. Since we were able to show that both Lingo-1 shRNA and DAPT could drive neural stem/progenitor cells differentiation, our data might aid the development of more effective SCI therapies using Lingo-1 shRNA and DAPT.

Prostaglandin E1 protects bone marrow-derived mesenchymal stem cells against serum deprivation-induced apoptosis.

Mesenchymal stem cells (MSCs) have become a recent focus of experimental and clinical research regarding myocardial regeneration. However, the therapeutic potential of these cells is limited by poor survival. Prostaglandin E1 (PGE1) is known to have anti­inflammatory and anti­apoptotic effects on the myocardium. The aim of the present study was to determine whether PGE1 could protect MSCs against serum deprivation (SD)­induced apoptosis. An SD model was used to induce apoptosis in MSCs in vitro. Apoptotic morphological changes were detected by Hoechst 33258 fluorescent nuclear staining; and Annexin V­fluorescein isothiocyanate/propidium iodide (PI) double staining and flow cytometry was used to quantify the rate of apoptosis. Western blot analysis was used to detect the expression levels of the apoptosis­associated proteins Bcl­2, Bax and caspase­3. The results of the present study demonstrated that SD induced apoptosis of MSCs, and that treatment with PGE1 attenuated the morphological changes characteristic of apoptosis. Annexin V/PI staining showed that the rate of apoptosis gradually increased with the duration of ischemia. Furthermore, treatment with PGE1 significantly reduced SD­induced apoptosis, decreased the protein expression levels of Bax and caspase­3, and increased the expression levels of Bcl­2. These data suggest that PGE1 is able to influence the survival of MSCs under certain conditions. These results may aid in improving the therapeutic efficacy of MSC transplantation used to treat chronic ischemic heart disease.

[Advances in cationic polymers used as nonviral vectors for gene delivery].

Gene therapy has been considered as a promising method for treatment of many diseases, such as acquired and genetic diseases. At present, there are two major vehicles for gene delivery including viral vectors and nonviral vectors. Viral vectors appear as high gene transfection efficiency, but some deficiencies such as inflammatory responses, recombination and mutagenesis have limited their use. On account of low pathogenicity, safety and cost-effectiveness, nonviral vectors have been attracted much attention. Cationic polymers are one of the nonviral vectors which have been widely studied. This review focuses on the structure of the cationic polymers and the interaction mechanism between the vector and DNA. We try to provide a framework for the future design and synthesis of nonviral vectors with high transfection efficiency and low toxicity for gene therapy.

A modified murine model for the study of reverse cardiac remodelling.

BACKGROUND: The authors previously reported a murine model of left ventricular hypertrophy (LVH) and regression using a suture technique of transverse aortic arch constriction and subsequent removal. A number of issues have limited the widespread adoption of this method. The present study assessed a modification of this model using a titanium clip. METHODS: Male C57BL/6 mice (n=95) underwent minimally invasive aortic banding for three, four or six weeks with or without subsequent band removal for one week. Hearts were evaluated both structurally and functionally using heart weight/body weight ratios, transthoracic echocardiography and direct left ventricular pressure measured using catheterization. RESULTS: Clip banding resulted in a threefold gradient across the transverse aortic arch. Pressure overload induced concentric LVH by three weeks that progressively decompensated. By six weeks, hearts were significantly dilated, with poor left ventricular function. Clips were removed in a minimally invasive procedure after each time point. When overloaded for either three or four weeks, removal of the clip with subsequent pressure relief enabled regression of LVH and restoration of function. When removed after six weeks of banding, mouse hearts were unable to reverse remodel and maintained elevated left ventricular end-diastolic pressures and lung congestion. CONCLUSIONS: The application and removal of a titanium clip successfully induced pressure overload and relief associated with the serial development and reversal of LVH. Compared with similar models using suture ligation and release, this method was found to be a simple, effective (no slipped bands) and reproducible method to study murine LVH, heart failure and its regression.

Local injection of lentivirus encoding LINGO-1-shRNA promotes functional recovery in rats with complete spinal cord transection.

STUDY DESIGN: We used a complete spinal cord transection model and locomotor function, histological, and immunohistochemical examinations to evaluate the effects of local injection of lentivirus/LINGO-1-short hairpin RNA (VL) on rats with spinal cord injury (SCI). OBJECTIVE: To demonstrate the neuroregenerative and neuroprotective effects of LINGO-1 RNAi on complete transection SCI rats. SUMMARY OF BACKGROUND DATA: LINGO-1 has been reported as a negative regulator of axonal sprouting and its antagonist was determined to improve functional outcomes in SCI rats. However, it has not been assessed whether blockade of LINGO-1 mediated by lentivirus vectors could stimulate neural recovery after SCI. METHODS: Complete spinal cord transection was made at T10 level. Suspension of lentivirus vectors encoding LINGO-1-short hairpin RNA was injected into the lesion gap. Controls received control vectors in the same manner and the sham group was subjected to laminectomy only. The Basso-Beattie-Bresnahan scale and surface righting reflex test were used to evaluate functional outcomes. Finally, the spinal cords were harvested for histological and immunohistochemical analysis. RESULTS: The treatment with VL improved Basso-Beattie-Bresnahan scores and surface righting reflex after SCI. Tissue repair was facilitated and the cavity area was significantly decreased in VL-treated animals. More sprouting and myelinated nerve fibers were detected within the injured site in the VL group as compared with the control. In addition, the number of survival neurons and oligodendrocytes around the epicenter was notably higher under the VL condition. CONCLUSION: Local injection of lentivirus/LINGO-1-short hairpin RNA after complete transection of spinal cord resulted in meaningful histological and functional outcomes in rats. The mechanism of VL protection may be related to its promotion of axonal sprouting, remyelination, and cell survival.

Hyperbranched cationic amylopectin derivatives for gene delivery.

A series of hyperbranched cationic amylopectin derivatives conjugated with 1,2-ethylenediamine, diethylenetriamine and 3-(dimethylamino)-1-propylamine residues, named as EDA-Amp, DETA-Amp and DMAPA-Amp, were synthesized by the N,N'-carbonyldiimidazole activation method at room temperature. Their structures were characterized by FTIR and (1)H NMR analyses, and their buffering capability was assessed by acid-base titration. The amylopectin derivatives exhibited better blood compatibility and lower cytotoxicity when compared to branched polyethyleneimine (bPEI) in the hemolysis and MTT assays. Atomic force microscopy and optical microscopy confirmed that the amylopectin derivatives exhibited lower damage for erythrocytes than bPEI. The amylopectin derivatives could bind and condense plasmid DNA (pDNA) to form the complexes with the size ranging from 100 to 300 nm. The resultant complexes showed higher transfection efficiency in 293T cells than in A549 cells. The DMAPA-Amp derivative-mediated gene transfection for Forkhead box O1 exhibited higher protein expression than that of the EDA-Amp and DETA-Amp derivatives in 293T cells, which was analyzed by western blot, flow cytometry and Hoechst staining assay. On the basis of these data, amylopectin derivatives exhibit potential as nonviral gene vectors.

Plasmid-encapsulated polyethylene glycol-grafted polyethylenimine nanoparticles for gene delivery into rat mesenchymal stem cells.

BACKGROUND: Mesenchymal stem cell transplantation is a promising method in regenerative medicine. Gene-modified mesenchymal stem cells possess superior characteristics of specific tissue differentiation, resistance to apoptosis, and directional migration. Viral vectors have the disadvantages of potential immunogenicity, carcinogenicity, and complicated synthetic procedures. Polyethylene glycol-grafted polyethylenimine (PEG-PEI) holds promise in gene delivery because of easy preparation and potentially targeting modification. METHODS: A PEG8k-PEI25k graft copolymer was synthesized. Agarose gel retardation assay and dynamic light scattering were used to determine the properties of the nanoparticles. MTT reduction, wound and healing, and differentiation assays were used to test the cytobiological characteristics of rat mesenchymal stem cells, fluorescence microscopy and flow cytometry were used to determine transfection efficiency, and atomic force microscopy was used to evaluate the interaction between PEG-PEI/plasmid nanoparticles and mesenchymal stem cells. RESULTS: After incubation with the copolymer, the bionomics of mesenchymal stem cells showed no significant change. The mesenchymal stem cells still maintained high viability, resettled the wound area, and differentiated into adipocytes and osteoblasts. The PEG-PEI completely packed plasmid and condensed plasmid into stable nanoparticles of 100-150 nm diameter. After optimizing the N/P ratio, the PEG-PEI/plasmid microcapsules delivered plasmid into mesenchymal stem cells and obtained an optimum transfection efficiency of 15%-21%, which was higher than for cationic liposomes. CONCLUSION: These data indicate that PEG-PEI is a valid gene delivery agent and has better transfection efficiency than cationic liposomes in mesenchymal stem cells.

[Application of orthogonal design in optimization of the transfection efficiency of polyethylenimine mediated gene transfer to hepatoma carcinoma cells].

This study was aimed to develop non-toxic, high transfection efficiency polyethyleneimine(PEI) cationic nanoparticles. The exosyndrome of PEI cationic nanoparticles was measured by zeta sizer, ultraviolet and visible spectroscopy. The condensation ability and the resistance to DNaseI of pEGFP-N1/PEI and pEGFP-N1/PEI modified polyethylene glycol(PEG) were evaluated by agarose gel electrophoresis. The cell toxicity of polyethyleneimine cationic nanoparticles was measured by using MTT test. The orthogonal design was used to optimize the transfection efficiency with the N/P ratio, the grafting ratio and the gene dosage as the factors. The experimental results showed that pEGFP-N1/PEI nanoparticles have lower cell toxicity, better composite ability and better resistance to DNAseI. The highest transfection efficiency of PEI cationic nanoparticles was 91% by using the PEI nanoparticles with the N/P ratio 40:1 and gene dosages 6 microg/well. PEI cationic nanoparticle modified by PEG effectively transferred DNA to hepatoma carcinoma cells and it is a non-toxic, with high transfection efficiency, and a promising non-viral carrier for gene delivery. The transfection efficiency will be improved by optimizing the experiment condition.

[Progress of nanometer vector polyethylenimine applied in gene therapy].

Polyethylenimine (PEI) is a kind of nanometer nonviral vector frequently applied in gene transfection. It is simple and easy to prepare and to modify and relatively safe compared to viral vectors. In recent years, PEI has been utilized in many research areas for gene delivery to stem cells in vitro or targeted gene delivery to cells in the brain. This review reveals that the cytotoxicity and low transfection efficiency of PEI requires to be improved. However brain-targeted modification indicates the promising prospect of PEI for gene therapy in cerebrovascular diseases.