In-situ constructed Cu/CuNC interfaces for low-overpotential reduction of CO2 to ethanol.

Electrochemical CO2 reduction (ECR) to high-value multi-carbon (C2+) products is critical to sustainable energy conversion, yet the high energy barrier of C-C coupling causes catalysts to suffer high overpotential and low selectivity toward specific liquid C2+ products. Here, the electronically asymmetric Cu-Cu/Cu-N-C (Cu/CuNC) interface site is found, by theoretical calculations, to enhance the adsorption of *CO intermediates and decrease the reaction barrier of C-C coupling in ECR, enabling efficient C-C coupling at low overpotential. The catalyst consisting of high-density Cu/CuNC interface sites (noted as ER-Cu/CuNC) is then accordingly designed and constructed in situ on the high-loading Cu-N-C single atomic catalysts. Systematical experiments corroborate the theoretical prediction that the ER-Cu/CuNC boosts electrocatalytic CO2-to-ethanol conversion with a Faradaic efficiency toward C2+ of 60.3% (FEethanol of 55%) at a low overpotential of -0.35 V. These findings provide new insights and an attractive approach to creating electronically asymmetric dual sites for efficient conversion of CO2 to C2+ products.

Interfacial assembly of binary atomic metal-Nx sites for high-performance energy devices.

Anion-exchange membrane fuel cells and Zn-air batteries based on non-Pt group metal catalysts typically suffer from sluggish cathodic oxygen reduction. Designing advanced catalyst architectures to improve the catalyst's oxygen reduction activity and boosting the accessible site density by increasing metal loading and site utilization are potential ways to achieve high device performances. Herein, we report an interfacial assembly strategy to achieve binary single-atomic Fe/Co-Nx with high mass loadings through constructing a nanocage structure and concentrating high-density accessible binary single-atomic Fe/Co-Nx sites in a porous shell. The prepared FeCo-NCH features metal loading with a single-atomic distribution as high as 7.9 wt% and an accessible site density of around 7.6 × 1019 sites g-1, surpassing most reported M-Nx catalysts. In anion exchange membrane fuel cells and zinc-air batteries, the FeCo-NCH material delivers peak power densities of 569.0 or 414.5 mW cm-2, 3.4 or 2.8 times higher than control devices assembled with FeCo-NC. These results suggest that the present strategy for promoting catalytic site utilization offers new possibilities for exploring efficient low-cost electrocatalysts to boost the performance of various energy devices.

Fabrication of Bacterial Cellulose-Based Dressings for Promoting Infected Wound Healing.

Bacterial cellulose (BC) holds several unique properties such as high water retention capability, flexibility, biocompatibility, and high absorption capacity. All these features make it a potential material for wound healing applications. However, it lacks antibacterial properties, which hampers its applications for infectious wound healings. This study reported BC-based dressings containing ε-polylysine (ε-PL), cross-linked by a biocompatible and mussel-inspired polydopamine (PDA) for promoting infectious wound healing. BC membranes were coated with PDA by a simple self-polymerization process, followed by treating with different contents of ε-PL. The resulted membranes showed strong antibacterial properties against tested bacteria by both in vitro and in vivo evaluations. The membranes also exhibited hemocompatibility and cytocompatibility by in vitro investigations. Moreover, the functionalized membranes promoted infected wound healing using Sprague-Dawley rats as a model animal. A complete wound healing was observed in the group treated with functionalized membranes, while wounds were still open for control and pure BC groups in the same duration. Histological investigations indicated that the thickness of newborn skin was greater and smoother in the groups treated with modified membranes in comparison to neat BC or control groups. These results revealed that the functionalized membranes have great potential as a dressing material for infected wounds in future clinical applications.

Fe-doped Co3O4 polycrystalline nanosheets as a binder-free bifunctional cathode for robust and efficient zinc-air batteries.

Fe-doped Co3O4 polycrystalline nanosheets vertically grown on carbon cloth were developed as self-standing efficient bifunctional electrocatalysts for oxygen reduction and evolution, enabling high-performance Zn-air batteries with a power density of 268.6 mW cm-2 and superior cycling stability.

Metastable Rock Salt Oxide-Mediated Synthesis of High-Density Dual-Protected M@NC for Long-Life Rechargeable Zinc-Air Batteries with Record Power Density.

Creating high-density durable bifunctional active sites in an air electrode is essential but still challenging for a long-life rechargeable zinc-air battery with appealing power density. Herein, we discover a general strategy mediated by metastable rock salt oxides for achieving high-density well-defined transition-metal nanocrystals encapsulated in N-doped carbon shells (M@NC) which are anchored on a substrate by a porous carbon network as highly active and durable bifunctional catalytic sites. Small-size (15 ± 5 nm) well-dispersed Co2Fe1@NC in a high density (metal loading up to 54.0 wt %) offers the zinc-air battery a record power density of 423.7 mW cm-2. The dual protection from the complete graphitic carbon shells and the anchoring of the outer carbon network make Co2Fe1@NC chemically and mechanically durable, giving the battery a long cycling life. Systematic in-situ temperature-dependent characterizations as well as DFT modeling rationalize the rock salt oxide-mediated process and its indispensable role in achieving high-density nanosized M@NC. These findings open up opportunities for designing efficient electrocatalysts for high-performance Zn-air batteries and diverse energy devices.

Saikosaponin-d Inhibits the Hepatoma Cells and Enhances Chemosensitivity Through SENP5-Dependent Inhibition of Gli1 SUMOylation Under Hypoxia.

Chemosensitivity is one of the key factors affecting the therapeutic effect on cancer, but the clinical application of corresponding drugs is rare. Hypoxia, a common feature of many solid tumors, including hepatocellular carcinoma (HCC), has been associated with resistance to chemotherapy in part through the activation of the Sonic Hedgehog (SHh) pathway. Hypoxia has also been associated with the increased SUMOylation of multiple proteins, including GLI family proteins, which are key mediators of SHh signaling, and has become a promising target to develop drug-resistant drugs for cancer treatment. However, there are few target drugs to abrogate chemotherapy resistance. Saikosaponin-d (Ssd), one of the main bioactive components of Radix bupleuri, has been reported to exert multiple biological effects, including anticancer activity. Here, we first found that Ssd inhibits the malignant phenotype of HCC cells while increasing their sensitivity to the herpes simplex virus thymidine kinase/ganciclovir (HSVtk/GCV) drug system under hypoxia in vitro and in vivo. Furthermore, we had explored that GLI family activation and extensive protein SUMOylation were characteristics of HCC cells, and hypoxia could activate the SHh pathway and promote epithelial-mesenchymal transition (EMT), invasion, and chemosensitivity in HCC cells. SUMOylation is required for hypoxia-dependent activation of GLI proteins. Finally, we found that Ssd could reverse the effects promoted by hypoxia, specifically active sentrin/small ubiquitin-like modifier (SUMO)-specific protease 5 (SENP5), a SUMO-specific protease, in a time- and dose-dependent manner while inhibiting the expression of SUMO1 and GLI proteins. Together, these findings confirm the important role of Ssd in the chemoresistance of liver cancer, provide some data support for further understanding the molecular mechanisms of Ssd inhibition of malignant transformation of HCC cells, and provide a new perspective for the application of traditional Chinese medicine in the chemical resistance of liver cancer.

Method validation of Q-PCR detection of host residual DNA in antibody drug based on protein A magnetic beads.

The residual DNA derived from host cells in antibody drugs have potential safety risks. In this paper, the antibody in the test sample was removed by magnetic bead separation method, and the residual DNA were quantitatively determined by Q-PCR method. The residual DNA in the sample was analyzed according to the standard curve. We validated the species specificity, accuracy, precision, quantitative restrictions, reproducibility of this method. The results showed the linearrange was of 1 × 10-1～1 × 102 pg/µL and the curve linear was good, this method can specifically detect CHO cell DNA. Compared with the method of extracting residual DNA by magnetic beads, the method has the advantages of simplicity, rapidity and low cost, and can be used for quantitative determination of the residual host cell DNA in antibody drugs producted by CHO cells.

Variation in expression of small ubiquitin-like modifiers in injured sciatic nerve of mice.

Small ubiquitin-like modifiers (SUMOs) have been shown to regulate axonal regeneration, signal transduction, neuronal migration, and myelination, by covalently and reversibly attaching to the protein substrates during neuronal cell growth, development, and differentiation. It has not been reported whether SUMOs play a role in peripheral nerve injury and regeneration. To investigate any association between SUMOylation and potential neuroprotective effects during peripheral nerve injury and regeneration, C57/BL mice were randomly divided into sham and experimental groups. The sciatic nerve was exposed only in the sham group. The experimental group underwent neurotomy and epineurial neurorrhaphy. Real-time quantitative polymerase chain reaction and western blot assay results revealed different mRNA and protein expression levels of SUMO1, SUMO2, SUMO3 and UBC9 in sciatic nerve tissue (containing both 5 mm of proximal and distal stumps at the injury site) at various time points after injury. Compared with the sham group, protein levels of SUMO1 and SUMO2/3 increased in both their covalent and free states after sciatic nerve injury in the experimental group, especially in the covalent state. UBC9 protein levels showed similar changes to those of SUMO1 and SUMO2/3 in the covalent states. Immunohistochemical staining demonstrated that SUMO1 and SUMO2/3 immunopositivities were higher in the experimental group than in the sham group. Our results verified that during the repair of sciatic nerve injury, the mRNA and protein expression of SUMO1, SUMO2, SUMO3 and UBC9 in injured nerve tissues changed in varying patterns and there were clear changes in the expression of SUMO-related proteins. These findings reveal that SUMOs possibly play an important role in the repair of peripheral nerve injury. All animal protocols were approved by the Institutional Animal Care and Use Committee of Tianjin Fifth Central Hospital, China (approval No. TJWZXLL2018041) on November 8, 2018.

Cascade anchoring strategy for general mass production of high-loading single-atomic metal-nitrogen catalysts.

Although single-atomically dispersed metal-Nx on carbon support (M-NC) has great potential in heterogeneous catalysis, the scalable synthesis of such single-atom catalysts (SACs) with high-loading metal-Nx is greatly challenging since the loading and single-atomic dispersion have to be balanced at high temperature for forming metal-Nx. Herein, we develop a general cascade anchoring strategy for the mass production of a series of M-NC SACs with a metal loading up to 12.1 wt%. Systematic investigation reveals that the chelation of metal ions, physical isolation of chelate complex upon high loading, and the binding with N-species at elevated temperature are essential to achieving high-loading M-NC SACs. As a demonstration, high-loading Fe-NC SAC shows superior electrocatalytic performance for O2 reduction and Ni-NC SAC exhibits high electrocatalytic activity for CO2 reduction. The strategy paves a universal way to produce stable M-NC SAC with high-density metal-Nx sites for diverse high-performance applications.

Polar Solvent Induced Lattice Distortion of Cubic CsPbI3 Nanocubes and Hierarchical Self-Assembly into Orthorhombic Single-Crystalline Nanowires.

Despite the recent surge of interest in inorganic lead halide perovskite nanocrystals, there are still significant gaps in their stability disturbance and the understanding of their destabilization, assembly, and growth processes. Here, we discover that polar solvent molecules can induce the lattice distortion of ligand-stabilized cubic CsPbI3, leading to the phase transition into orthorhombic phase, which is unfavorable for photovoltaic applications. Such lattice distortion triggers the dipole moment on CsPbI3 nanocubes, which subsequently initiates the hierarchical self-assembly of CsPbI3 nanocubes into single-crystalline nanowires. The systematic investigations and in situ monitoring on the kinetics of the self-assembly process disclose that the more amount or the stronger polarity of solvent can induce the more rapid self-assembly and phase transition. These results not only elucidate the destabilization mechanism of cubic CsPbI3 nanocrystals, but also open up opportunities to synthesize and store cubic CsPbI3 for their practical applications in photovoltaics and optoelectronics.

Crystallinity-Modulated Electrocatalytic Activity of a Nickel(II) Borate Thin Layer on Ni3 B for Efficient Water Oxidation.

The exploration of new efficient OER electrocatalysts based on nonprecious metals and the understanding of the relationship between activity and structure of electrocatalysts are important to advance electrochemical water oxidation. Herein, we developed an efficient OER electrocatalyst with nickel boride (Ni3 B) nanoparticles as cores and nickel(II) borate (Ni-Bi ) as shells (Ni-Bi @NB) via a very simple and facile aqueous reaction. This electrocatalyst exhibited a small overpotential of 302 mV at 10 mA cm-2 and Tafel slope of 52 mV dec-1 . More interestingly, it was found that the OER activity of Ni-Bi @NB was closely dependent on the crystallinity of the Ni-Bi shells. The partially crystalline Ni-Bi catalyst exhibited much higher activity than the amorphous or crystalline analogues; this higher activity originated from the enhanced intrinsic activity of the catalytic sites. These findings open up opportunities to explore nickel(II) borates as a new class of efficient nonprecious metal OER electrocatalysts, and to improve the electrocatalyst performance by modulating their crystallinity.

[Testing immunogenicity of recombinant antibody by surface plasmon resonance].

With the development of bio-technological drugs, drug immunogenicity evaluation has become key factor of clarifying safety and efficacy of these drugs. It has become the focus to establish a stable and reliable evaluation system. Due to the advantages such as continuous real-time monitoring, surface plasmon resonance (SPR) technology has been widely used in bio-technological drugs immunogenicity assessments. Our study applied this technology to detect anti-drug antibody (ADA) of a recombinant human anti-rabies monoclonal antibody NM57 in the sera of 48 volunteers admitted in phase I clinical trials. This method could satisfy the basic requirements of detection of ADA.

A meta-analysis of carotid endarterectomy versus stenting in the treatment of symptomatic carotid stenosis.

BACKGROUND: Carotid stenosis is one of the common reasons for patients with ischemic stroke, and the two invasive options carotid endarterectomy (CEA) and carotid artery stenting (CAS) are the most popular treatments. But the relative efficacy and safety of the methods are not clear. METHODS: About 521 articles related to CAS and CEA for carotid stenosis published in 1995 - 2011 were retrieved from MEDLINE, Cochrane Library (CL), and China National Knowledge Infrastructure (CNKI) China Journal Full-Test database. Of them, eight articles were chosen. Meta-analysis was used to assess the relative risks. RESULTS: The eight studies included 3873 patients with symptomatic carotid artery stenosis, including 1941 cases in the carotid stent angioplasty group, and 1932 cases in the carotid endarterectomy group. Fixed effect model analysis showed that within 30 days of incidence of all types of strokes, surgery was significantly highly preferred in CAS patients (CAS group) than the CEA patients (CEA group), and the difference was statistically significant (relative ratio (RR) = 1.80, 95% confidence interval (CI): 1.380 - 2.401, P < 0.0001). But the incidence of death in the two groups is not showed and is not statistically significant after 30 days (RR = 1.52, 95%CI: 0.82 - 2.82, P = 0.18). The rate of cranial nerve injury in the CAS group is lower than the CEA group (RR = 0.14, 95%CI: 0.05 - 0.43, P = 0.0005). The incidence of CAS patients with myocardial infarction is lower than the CEA group after 30 days, but statistically meaningless (RR = 0.22, 95%CI: 0.05 - 1.02, P = 0.05). The stroke or death in CAS patients were higher than the CEA group after 1 year of treatment (RR = 2.58, 95%CI: 1.03 - 6.48, P = 0.04). CONCLUSIONS: Compared to CAS, carotid endarterectomy is still the preferred treatment methodology of symptomatic carotid artery stenosis. Future meta-analyses should then be performed in long-term follow-up to support this treatment recommendation.

[Inhibitory effect of folic acid/polyamide-amine as a miR-7 vector on the growth of glioma in mice].

OBJECTIVE: To explore if folic acid/polyamide-amine (FA/PAMAM) enhances the therapeutic effect of miR-7gene therapy for glioma in vivo. METHODS: The miR-7 gene was transfected into U251 glioma cells by FA/PAMAM. The efficiency of gene transfection was assessed by fluorescence microscopy. The miR-7 level was detect by quantitative RT-PCR. Intracranial glioma models were established in thymectomized mice, and FA/PAMAM nanoparticles were transplanted into the tumors in situ 3 days later. The animal survival was recorded and the gross tumor volume and degree of edema were observed by MRI. Apoptosis in the glioma cells and expression of proliferating cell nuclear antigen (PCNA), matrix metalloproteinases 2 and 9 (MMP-2 and MMP-9) were assessed by immunohistochemistry, and EGFR and AKT-2 protein expression was detected by Western blot assay. RESULTS: Compared with the liposomes, the FA/PAMAM nanoparticles were more efficient to transfer miR-7 gene into U251 glioma cells, MRI showed that the tumor growth was much slower in the FA/PAMAM/miR-7 group, and the animal survival time was longer. The apoptosis rate was (5.3 ± 0.9)% in the control group, (11.4 ± 2.4)% in the liposome/miR-7 group, and (17.7 ± 3.7)% in the FA/PAMAM/miR-7 group. The immunohistochemical assay showed that the levels of PCNA, MMP-2 and MMP-9 protein in the FA/PAMAM/miR-7 group were (34.6 ± 5.4)%, (24.5 ± 4.1)%, (25.4 ± 5.1)%, respectively, significantly lower than those in the liposome/miR-7 group (49.3 ± 5.9)%, (31.7 ± 7.1)% and (39.4 ± 6.4)%, respectively, and those in the control group (57.3 ± 7.4)%, (45.4 ± 6.9)% and (55.1 ± 7.3)%, respectively (all P < 0.05). The expressions of EGFR and AKT-2 proteins were 1.09 ± 0.12 and 0.62 ± 0.10 in the control group, 0.63 ± 0.11 and 0.43 ± 0.07 in the liposome/miR-7 group, and significantly deceased (0.47 ± 0.09 and 0.31 ± 0.04, respectively) in the FA/PAMAM/miR-7 group (all P < 0.05). CONCLUSION: Compared with the liposomes, FA/PAMAM can transfect miR-7 into glioma cells with a higher efficiency in vivo, makes a longer time of the drug action, and shows a certain inhibitory effect on the growth of glioma, therefore, might become a new drug targeting agent in gene therapy forglioma.

[Clinical study on pulmonary circulation changes in patients with acute respiratory distress syndrome induced by lung contusion].

OBJECTIVE: To analyze the variation and significance of pulmonary circulation in patients with acute respiratory distress syndrome (ARDS) induced by lung contusion by means of Swan-Ganz catheter and the pulse index continuous cardiac output (PiCCO) monitoring. METHODS: A prospective, randomized, non-blinded clinical trial was conducted. All patients admitted hospital from August 2009 to August 2011 met the inclusion criteria, were divided into the group with ARDS induced by lung contusion (contusion group, n = 18) and the group without lung contusion and ARDS (control group, n = 22). The measured parameters included pulmonary artery systolic pressure (PAS), pulmonary artery diastolic pressure (PAD), pulmonary artery wedge pressure (PAWP), pulmonary artery diastolic-pulmonary wedge pressure gradient (PAD-PAWP), and extravascular lung water index (ELWI) of each group at 0 hour after placing the catheter and at 12, 24, 36, 48, 60, 72 hours after contusion. The differences of all the parameters were compared within a group and among the different groups. RESULTS: In the survivors with ARDS induced by lung contusion, PAS, PAD and PAD-PAWP were significantly higher than those in the control group and then gradually declined. PAS and PAD returned to the level of control group at 60 hours after contusion, and the PAD-PAWP restored to the level of control group at 48 hours after contusion. For the patients in the control group, there were no significant differences in PAS and PAD from the 0 hour after placing catheter to 72 hours after contusion, but PAD-PAWP increased at 72 hours after contusion compared with at 48 hours. Compared with the control group, the ELWI in contusion group increased significantly, and peaked at 12 hours after contusion and then gradually declined, and restored to the level of control group at 60 hours after contusion. For the patients in the control group, ELWI were lower at 60 hours and 72 hours after contusion than at 48 hours. Compared with control group, PAWP in contusion group decreased at 0 hour, and returned to the level of control group at 48 hours after contusion. For the patients in the control group, there were no significant differences in PAWP from the 0 hour after placing the catheter to 72 hours after contusion. The positive correlation were found between ELWI and PAS, PAD, PAD-PAWP from 0 hour after placing the catheter to 48 hours after contusion in contusion group (r value, 0.554, 0.498, 0.629, respectively, all P < 0.01). CONCLUSION: Among the patients with ARDS induced by lung contusion, it appears that changes in PAS, PAD and PAD-PAWP, as well as ELWI play important roles in assessing fluid status, guiding mechanical ventilation and severity.

Combination of temperature-sensitive stem cells and mild hypothermia: a new potential therapy for severe traumatic brain injury.

Stem cell transplantation holds great potential for the treatment of traumatic brain injury (TBI). However, the micro-environment of reduced oxygen and accumulated toxins leads to low survival rates of grafted cells, which dramatically limits their clinical application. Mild hypothermia has been demonstrated to improve the micro-environment after severe TBI. Thus, we speculate that combinational therapy of mild hypothermia may promote survival of grafted cells, especially temperature-sensitive stem cells, which show the most activity in mild temperatures. In this study, we first isolated mesenchymal stem cells from umbilical cord (UCSMCs) and generated the temperature-sensitive UCSMCs (tsUCSMCs) by infection with a retrovirus carrying the temperature-sensitive tsA58 SV40 LT antigen gene. We demonstrated that tsUCSMCs grew and proliferated with more activity at 33°C than at 37°C by counting cell numbers with a hematocytometer, measuring the cell cycle with flow cytometry, and detecting proliferating cell nuclear antigen (PCNA) with immunofluorescence staining. Thereafter, we established the rat severe TBI model by fluid percussion, and injected PBS, UCSMCs, or tsUCSMCs into the injured region, and subject the animals to normothermia or mild hypothermia (33°C). We found that, compared with UCSMC or tsUCSMC treatment alone, their combination with hypothermia could significantly improve motor and cognitive function with more survival of the grafted cells. Furthermore, we observed that combined therapy with hypothermia and tsUCSMCs exerted the most protective effect on the recovery of neurological function of all the tested treatments, with the highest survival and proliferation rates, and the lowest apoptosis rate. Thus this may represent a new therapeutic strategy for the treatment of severe TBI.

[Application of fenestration and suction drainage for treatment of large odontogenic mandibular cystic lesions].

OBJECTIVE: To evaluate the effect of fenestration and suction drainage in the treatment of large odontogenic mandibular cystic lesions. METHODS: From 2005 to 2009, 24 cases of large odontogenic mandibular cystic lesions were treated with fenestration and suction drainage. The clinical symptoms and radiographical findings were evaluated before the operation and at 1 month and 6 months after suction drainage. RESULTS: Follow-up for 1-3 years showed that all the cystic lesions disappeared without recurrence, and the clinical symptoms were resolved. CONCLUSION: Fenestration and suction drainage can reduce the cystic size and rapidly correct the deformity to serve as a useful modality for primary management of large odontogenic mandibular cystic lesions.

[Study on reversion of malignant phenotype of glioma by siRNA targeting p75 neurotrophin receptor].

OBJECTIVE: To study the therapeutic efficacy of siRNA fragments silencing p75 neurotrophin receptor (p75(NTR)), which may be a key regulator of glioma cell apoptosis and invasion. METHODS: The siRNA sequence fragments targeting p75(NTR) were designed and transferred into human glioma cell line U251. RT-PCR and immunocytochemistry method were used to explore the expression of p75(NTR) mRNA and protein. Cell adhesion assay was employed to detect cellular adhesion ability, and soft agar clone formation assay was adopted to identify oncogenicity, and a U251 glioma model was established in nude mice. The intracranial tumor volume was detected by MRI. The expression of p75(NTR), NGF and cyclin D2 were identified using immunohistochemistry. Cell apoptosis was detected by apoptosis kit in situ. RESULTS: The siRNA fragments targeting p75(NTR) were capable of decreasing mRNA and protein expression of p75(NTR) in U251 glioma cell line. Both the cellular adhesion ability and oncogenicity were weakly relevant. The p75(NTR) expression level was negatively correlated with cyclin D2 and apoptosis, and positively correlated with NGF expression. The siRNA sequence fragments targeting p75(NTR) were effective in decreasing the gross volume of tumor; prolonged the survival time of mice, and the edge of tumor was much sharper than that of the control group. CONCLUSIONS: The gene silencing technique by siRNA targeting p75(NTR) is capable of decreasing tumor invasion and cell proliferation as well as inducing cell apoptosis. It is expected to be a new choice for glioma gene therapy.

Tropism mechanism of stem cells targeting injured brain tissues by stromal cell-derived factor-1.

OBJECTIVE: To explore the role and function of stromal cell-derived factor-1 (SDF-1) in stem cells migrating into injured brain area. METHODS: Rat-derived nerve stem cells (NSCs) were isolated and cultured routinely. Transwell system was used to observe the migration ability of NSCs into injured nerve cells. Immunocytochemistry was used to explore the expression of chemotactic factor receptor-4 (CXCR-4) in NSCs. In vivo, we applied immunofluorescence technique to observe the migration of NSCs into injured brain area. Immunofluorescence technique and Western blotting were used to test expression level of SDF-1. After AMD3100 (a special chemical blocker) blocking CXCR-4, the migration ability of NSCs was tested in vivo and in vitro, respectively. RESULTS: NSCs displayed specific tropism for injured nerve cells or traumatic brain area in vivo and in vitro. The expression level of SDF-1 in traumatic brain area increased remarkably and the expression level of CXCR-4 in the NSCs increased simultaneously. After AMD3100 blocking the expression of CXCR-4, the migration ability of NSCs decreased significantly both in vivo and in vitro. CONCLUSIONS: SDF-1 may play a key role in stem cells migrating into injured brain area through specially combining with CXCR-4.