Publications by authors named "Dagui Chen"

21 Publications

  • Page 1 of 1

Bone Regeneration Using MMP-Cleavable Peptides-Based Hydrogels.

Gels 2021 Nov 5;7(4). Epub 2021 Nov 5.

Department of Trauma Orthopedics, Changhai Hospital, Naval Medical University, Shanghai 200433, China.

Accumulating evidence has suggested the significant potential of chemically modified hydrogels in bone regeneration. Despite the progress of bioactive hydrogels with different materials, structures and loading cargoes, the desires from clinical applications have not been fully validated. Multiple biological behaviors are orchestrated precisely during the bone regeneration process, including bone marrow mesenchymal stem cells (BMSCs) recruitment, osteogenic differentiation, matrix calcification and well-organized remodeling. Since matrix metalloproteinases play critical roles in such bone metabolism processes as BMSC commitment, osteoblast survival, osteoclast activation matrix calcification and microstructure remodeling, matrix metalloproteinase (MMP) cleavable peptides-based hydrogels could respond to various MMP levels and, thus, accelerate bone regeneration. In this review, we focused on the MMP-cleavable peptides, polymers, functional modification and crosslinked reactions. Applications, perspectives and limitations of MMP-cleavable peptides-based hydrogels for bone regeneration were then discussed.
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http://dx.doi.org/10.3390/gels7040199DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8628702PMC
November 2021

Stepwise chemical oxidation to access ultrathin metal (oxy)-hydroxide nanosheets for the oxygen evolution reaction.

Nanoscale 2021 Oct 1;13(37):15755-15762. Epub 2021 Oct 1.

College of Electronics and Information Science & Organic Optoelectronics Engineering Research Center of Fujian's Universities, Fujian Jiangxia University, Fuzhou, Fujian 350108, P.R. China.

Incorporation of ultrathin nanosheets with dopants/defects shows great potential to enable metal (oxy)-hydroxide electrocatalysts with enhanced oxygen evolution reaction (OER) performance the regulation of atomic structure and bonding arrangements. However, it remains challenging in synthesis especially for such dual control and at large scale. In this study, we present a stepwise chemical oxidation route, involving phase transition and reconstruction processes, to access ultrathin CoOOH nanosheets with a thickness of 4 nm and abundant oxygen vacancies. Other transition metals were also doped into CoOOH nanosheets through this strategy. Among them, the optimized FeCoOOH nanosheets demonstrated an efficient OER activity with overpotential as low as 252 mV (current density: 10 mA cm) and excellent stability. A high and stable solar-to-hydrogen efficiency of 10.5% was acquired when FeCoOOH nanosheets were used as the anode in a constructed water splitting device driven by solar energy. This study offers a noble and facile strategy for potentially scalable preparation of atom-modulated ultrathin metal (oxy)-hydroxide nanosheets, and also demonstrates the OER applications.
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http://dx.doi.org/10.1039/d1nr03813cDOI Listing
October 2021

Cyclic GMP-AMP promotes the acute phase response and protects against Escherichia coli infection in mice.

Biochem Pharmacol 2021 06 1;188:114541. Epub 2021 Apr 1.

Institute of Translational Medicine, Shanghai University, Shanghai, China. Electronic address:

The acute phase response, as a component of the innate immune system, is part of the first line of defense against invading pathogens. The Stimulator of Interferon Genes (STING) pathway initiates innate immune responses upon recognition of exogenous bacterial and viral DNA. However, whether STING signaling pathway plays any roles in regulating acute phase response during bacterial infection remains unknown. In this study, we used STING-deficient (Tmem173) and wildtype mice to investigate acute phase responses to bacterial infection (Escherichia coli, E. coli) and test the effect of exogenous cyclic GMP-AMP (cGAMP, a STING agonist) treatment. Bacterial infection of STING-deficient mice resulted in an increase in mortality and bacterial dissemination. Also, inflammation-induced acute phase response was drastically reduced in STING-deficient mice, showing significant reduction in expression of cytokine TNF-α and acute phase proteins. In contrast, exogenous cGAMP treatment enhanced inflammation-induced acute phase response by increasing the expression of TNF-α and acute phase proteins. Also, cGAMP accelerated bacterial clearance and improved survival rate of wildtype mice, but not STING-deficient mice. Interestingly, cGAMP treatment mitigated bacterial infection induced liver injury in both wildtype and STING-deficient mice. Further in vitro evidence showed that cGAMP treatment retarded TNF-α-mediated hepatocyte apoptosis, potentially accelerating autophagy. Taken together, our results indicated that cGAMP/STING signaling pathway is critical for organism to initiate blood-borne innate immune-responses to defend bacterial infection, and cGAMP is envisaged as a drug candidate for further clinical trial.
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http://dx.doi.org/10.1016/j.bcp.2021.114541DOI Listing
June 2021

Protein liposomes-mediated targeted acetylcholinesterase gene delivery for effective liver cancer therapy.

J Nanobiotechnology 2021 Jan 22;19(1):31. Epub 2021 Jan 22.

State Key Laboratory of Oncogenes and Related Genes, Shanghai Cancer Institute, Shanghai Jiao Tong University School of Medicine Affiliated Renji Hospital, Shanghai, 200032, People's Republic of China.

Background: Effective methods to deliver therapeutic genes to solid tumors and improve their bioavailability are the main challenges of current medical research on gene therapy. The development of efficient non-viral gene vector with tumor-targeting has very important application value in the field of cancer therapy. Proteolipid integrated with tumor-targeting potential of functional protein and excellent gene delivery performance has shown potential for targeted gene therapy.

Results: Herein, we prepared transferrin-modified liposomes (Tf-PL) for the targeted delivery of acetylcholinesterase (AChE) therapeutic gene to liver cancer. We found that the derived Tf-PL/AChE liposomes exhibited much higher transfection efficiency than the commercial product Lipo 2000 and shown premium targeting efficacy to liver cancer SMMC-7721 cells in vitro. In vivo, the Tf-PL/AChE could effectively target liver cancer, and significantly inhibit the growth of liver cancer xenografts grafted in nude mice by subcutaneous administration.

Conclusions: This study proposed a transferrin-modified proteolipid-mediated gene delivery strategy for targeted liver cancer treatment, which has a promising potential for precise personalized cancer therapy.
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http://dx.doi.org/10.1186/s12951-021-00777-9DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7821407PMC
January 2021

Boosting water oxidation activity by tuning the proton transfer process of cobalt phosphonates in neutral solution.

Phys Chem Chem Phys 2020 Jul;22(25):14255-14260

College of Electronics and Information Science & Organic Optoelectronics Engineering Research Center of Fujian's Universities, Fujian Jiangxia University, Fuzhou, Fujian 350108, P. R. China.

Water oxidation is a vital step in both natural and artificial photosynthetic processes. However, the effect of second coordination sphere for efficient oxygen evolution electrocatalysts has rarely been studied, becoming a bottleneck in many energy-related issues. In this article, the cobalt phosphonate (NH3C6H4NH3)Co2(hedpH)2·H2O (Co-PDA) displayed decent electrocatalytic water oxidation activity in 50 mM PBS solution (pH 7.0), comparable to the activity of state-of-the-art IrO2. Moreover, it exhibited a 160 mV lower onset potential and 6 times higher TOF than those of the counterpart, (NH4)2Co2(hedpH)2 (Co-NH4+), which existed with the same Co active center, while surrounded by different ligands. The related mechanistic studydemonstrates that the ligand in Co-PDA would benefit the proton-coupled electron transfer (PCET) processes and the formation of high valence state Co(iv).
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http://dx.doi.org/10.1039/d0cp02194fDOI Listing
July 2020

Low-Power Flexible Organic Field-Effect Transistors with Solution-Processable Polymer-Ceramic Nanoparticle Composite Dielectrics.

Nanomaterials (Basel) 2020 Mar 12;10(3). Epub 2020 Mar 12.

Organic Optoelectronics Research Center in Fujian Universities, College of Electronics and Information Science, Fujian Jiangxia University, Fuzhou 350108, China.

Polymer-ceramic dielectric composites have been of great interest because they combine the processability of polymers with the desired dielectric properties of the ceramics. We fabricated a low voltage-operated flexible organic field-effect transistor (OFET) based on crosslinked poly (4-vinyl phenol) (PVP) polymer blended with novel ceramic calcium titanate nanoparticles (CaTiO NPs) as gate dielectric. To reduce interface roughness caused by nanoparticles, it was further coated with a very thin PVP film. The resulting OFET exhibited much lower operated voltage (reducing from -10.5 V to -2.9 V), a relatively steeper threshold slope (~0.8 V/dec) than those containing a pure PVP dielectric. This is ascribed to the high capacitance of the CaTiO NP-filled PVP insulator, and its smoother and hydrophobic dielectric surface proved by atomic force microscopy (AFM) and a water contact angle test. We also evaluated the transistor properties in a compressed state. The corresponding device had no significant degradation in performance when bending at various diameters. In particular, it operated well continuously for 120 hours during a constant bending stress. We believe that this technology will be instrumental in the development of future flexible and printed electronic applications.
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http://dx.doi.org/10.3390/nano10030518DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7153480PMC
March 2020

Administration of nimotuzumab combined with cisplatin plus 5-fluorouracil as induction therapy improves treatment response and tolerance in patients with locally advanced nasopharyngeal carcinoma receiving concurrent radiochemotherapy: a multicenter randomized controlled study.

BMC Cancer 2019 Dec 30;19(1):1262. Epub 2019 Dec 30.

Department of Oncology, the Fourth Affiliated Hospital of Guangxi Medical University, Liuzhou, China.

Background: Nimotuzumab (NTZ) is an anti-EGFR monoclonal antibody. However,the effect of targeted drugs combined with induction therapy in locally advanced nasopharyngeal carcinoma remains unclear. The aim of this study is to investigate the safety and efficacy of NTZ combined with cisplatin plus 5-fluorouracil (PF) as induction regimen in locally advanced nasopharyngeal carcinoma (NPC) patients receiving concurrent radiochemotherapy.

Methods: This was a multicenter randomized controlled study performed in eight Guangxi hospitals in 2015-2017. Eligible patients with NPC were randomized into nimotuzumab/PF (NPF group) and docetaxel/PF (DPF group) regimens, respectively, as induction therapy. After 2 cycles of induction therapy, all patients received cisplatin and concurrent intensity modulated radiation therapy (IMRT). Then, the two groups were compared for safety and efficacy.

Results: A total of 118 patients with stage III-IVa NPC were assessed, with 58 and 60 in the NPF and DPF groups, respectively. Compared with DPF treatment, NPF induction therapy showed a more pronounced effect on cervical lymph nodes (P = 0.036), with higher response rate (RR) (81% vs 60%). Compared with the DPF group, the NPF group showed significantly reduced leukopenia, neutropenia and gastrointestinal reactions (all P < 0.05); rash only appeared in the NPF group, but all cases were grade 1. During concurrent treatment with radiotherapy and chemotherapy, the NPF group showed better tolerance to radiotherapy and chemotherapy; neutropenia, anemia, gastrointestinal reactions, oral mucositis and radiation dermatitis in the NPF group were significantly reduced (P < 0.05). The expression rate of EGFR was 94.9% (112/118). Compared with the DPF group, patients with EGFR expression in the NPF group showed better response (77.8% vs 63.0%, P = 0.033).

Conclusion: For locally advanced NPC patients receiving follow-up cisplatin and IMRT, nimotuzumab/PF for induction therapy has better lymph node response rate and milder adverse reactions than the DPF regimen. In addition, the patients have better tolerance in subsequent concurrent radiotherapy and chemotherapy; however, long-term efficacy needs further follow-up evaluation.

Trial Registration: The registration number of the clinical trial is ChiCTR-OIC-16008201 and retrospectively registered on March 31, 2016.
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http://dx.doi.org/10.1186/s12885-019-6459-6DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6937916PMC
December 2019

Incorporating N Atoms into SnO₂ Nanostructure as an Approach to Enhance Gas Sensing Property for Acetone.

Nanomaterials (Basel) 2019 Mar 15;9(3). Epub 2019 Mar 15.

Organic Optoelectronics Engineering Research Center of Fujian's Universities, Fujian Jiangxia University, Fuzhou 350108, China.

The development of high-performance acetone gas sensor is of great significance for environmental protection and personal safety. SnO₂ has been intensively applied in chemical sensing areas, because of its low cost, high mobility of electrons, and good chemical stability. Herein, we incorporated nitrogen atoms into the SnO₂ nanostructure by simple solvothermal and subsequent calcination to improve gas sensing property for acetone. The crystallization, morphology, element composition, and microstructure of as-prepared products were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), Electron paramagnetic resonance (EPR), Raman spectroscopy, UV⁻visible diffuse reflectance spectroscopy (UV⁻vis DRS), and the Brunauer⁻Emmett⁻Teller (BET) method. It has been found that N-incorporating resulted in decreased crystallite size, reduced band-gap width, increased surface oxygen vacancies, enlarged surface area, and narrowed pore size distribution. When evaluated as gas sensor, nitrogen-incorporated SnO₂ nanostructure exhibited excellent sensitivity for acetone gas at the optimal operating temperature of 300 °C with high sensor response (R/R - 1 = 357) and low limit of detection (7 ppb). The nitrogen-incorporated SnO₂ gas sensor shows a good selectivity to acetone in the interfering gases of benzene, toluene, ethylbenzene, hydrogen, and methane. Furthermore, the possible gas-sensing mechanism of N-incorporated SnO₂ toward acetone has been carefully discussed.
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http://dx.doi.org/10.3390/nano9030445DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6474091PMC
March 2019

Astragaloside IV Induced miR-134 Expression Reduces EMT and Increases Chemotherapeutic Sensitivity by Suppressing CREB1 Signaling in Colorectal Cancer Cell Line SW-480.

Cell Physiol Biochem 2017 17;43(4):1617-1626. Epub 2017 Oct 17.

Fuzhou General Hospital of Nanjing Military Region, Fujian Province, Fuzhou, China.

Background: Colorectal cancer (CRC) is one of the leading causes of cancer-related deaths worldwide. Although chemotherapy is the primary means in colorectal cancer treatment, it is burdenerd by adverse drug effects. Drug-resistance is one of the most important challenges for chemotherapy and epithelial-mesenchymal transition (EMT) plays critical role in the development of drug resistance.

Aims: The aim of this study was to investigate the mechanisms underlying the effect of astragaloside IV (AS-IV) on miR-134 expression, EMT and chemotherapeutic sensitivity in CRC.

Methods: Cell proliferation, transfection assay, western blot, real-time PCR, cell migration and invasion assay and luciferase reporter assay were used to detect the effects of AS-IV on CRC.

Results: AS-IV significantly inhibited CRC cell migration and invasion by inducing miR-134 expression. Moreover, AS-IV and miR-134 increased the sensitivity of CRC tumors to oxaliplatin (OXA) chemotherapy. cAMP responsive element-binding protein 1 (CREB1), which was required for CRC cells migration, invasion and drug sensitivity, was significantly down-regulated by AS-IV.

Conclusions: Our results indicated that AS-IV inhibited CRC EMT by inducing miR-134 expression which significantly down-regulated the CREB1 signaling pathway, and therefore increased the sensitivity to chemotherapy. Our findings provided new insight into the mechanisms of chemotherapy-resistant CRC, and may open new therapeutic options in the treatment of this devastating disease.
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http://dx.doi.org/10.1159/000482025DOI Listing
December 2017

Randomized controlled trial of late-course concurrent versus sequential chemoradiotherapy after mastectomy and axillary surgery in locally advanced breast cancer.

Medicine (Baltimore) 2017 Oct;96(41):e8252

Department of Oncology, Fourth Affiliated Hospital of Guangxi Medical University, Liuzhou, Gaungxi, China.

Background: Concurrent chemoradiotherapy could increase the local control rate in patients with high recurrence risk after breast-conserving surgery, but the effect of concurrent chemoradiotherapy after mastectomy and axillary dissection is not clear. The aim of the study was to compare the effects of late-course concurrent chemoradiotherapy (CCRT) versus sequential therapy (SCRT) after mastectomy and axillary surgery in locally advanced breast cancer.

Methods: This was a randomized controlled trial of 155 patients with stage pT3-4p N1-3c M0 or pAnyT pN2-3c M0 breast cancer undergoing 5-fluorouracil+epirubicin+cyclophosphamide followed by docetaxel (FEC-D) chemotherapy after mastectomy and axillary dissection. Patients were randomized to the CCRT group (intensity-modulated radiation therapy was performed concurrently with docetaxel) or to the SCRT group (radiotherapy after chemotherapy). Recurrences, adverse reactions, and short-term effects were observed.

Results: All the patients completed the planned therapy. The median follow-up was 39 (range, 16-62) months. Compared with SCRT, the 3-year local-regional recurrence-free survival (LRFS) in the CCRT group was improved (81.8% vs 92.3%, P = .046). There was no significant difference in 3-year disease-free survival (DFS) and overall survival (OS). In the pT3-4 pN1-3 cM0 subgroup, the 3-year local recurrence-free survival and DFS were significantly improved in the CCRT group (69.4% vs 88.2%, P = .036; and 41.7% vs 72.6%, P = .049, respectively). No significant difference was observed adverse reactions between the 2 groups.

Conclusion: LRFS of patients with locally advanced invasive breast cancer after mastectomy and axillary surgery was better with CCRT than with SCRT and with similar profiles of adverse reactions. The DFS of patients staged pT3-4 pN1-3 cM0 was also improved.
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http://dx.doi.org/10.1097/MD.0000000000008252DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5662317PMC
October 2017

Small molecule inhibitor TW-37 is tolerable and synergistic with chemotherapy in nasopharyngeal carcinoma.

Cell Cycle 2017 Jul 11;16(14):1376-1383. Epub 2017 Jul 11.

a Department of Radiation Oncology , First Affiliated Hospital of Guangxi Medical University , Nanning , China.

Chemotherapy is a crucial adjuvant therapy of advanced nasopharyngeal carcinoma (NPC). However, enhancing sensitivity and tolerance of chemotherapeutics in NPC treatment have been challenging. Both Bcl-2 and Mcl-1, 2 pro-survival proteins of Bcl-2 family, play essential roles on the chemotherapy tolerance of numerous cancers. In the present study, we explored the influences of TW-37, a small molecule inhibitor of Bcl-2 and Mcl-1, on the efficiency of chemotherapy for NPC. Oncomine cancer database shows that NPC tissues have higher expression of Bcl-2 and Mcl-1 than those of normal nasopharyngeal epithelial (NPE) tissues. And our results reveal that chemotherapeutics, Cisplatin (CDDP) and 5-Fluoracil (5-FU), result in the greater decrease of protein level of Bcl-2 and Mcl-1 in NPC cells than those in NPE cells. TW-37 does not have significant impact on the chemotherapeutics-treated NPE cell viability at a dosage that efficiently reduces chemotherapeutics-treated NPC cell viability. Moreover, impacts of TW-37 on the cell viability of chemotherapeutics-treated NPC cells are dependent on the expression of Bcl-2 and Mcl-1 in NPC cells. Further explorations suggest that TW-37 prominently promotes apoptosis in NPC cells under chemotherapeutics treatments but not in NPE cells. Meanwhile, TW-37 also remarkably reduces colony formation ability of chemotherapeutics-treated NPC cells. Importantly, in vivo models, TW-37 observably increases chemosensitivity of NPC tumors but has not markedly influence on the normal tissues in mice. In conclusion, our results point to TW-37 as a promising ancillary drug for the chemotherapy of NPC.
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http://dx.doi.org/10.1080/15384101.2017.1329066DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5539829PMC
July 2017

ZnS nanoarchitectures induced dysfunction of vascular endothelial cells in vitro and in vivo.

Environ Toxicol 2015 Jul 21;30(7):755-68. Epub 2014 Jan 21.

Shandong Provincial Key Laboratory of Animal Cells and Developmental Biology, School of Life Science, Shandong University, Jinan, 250100, China.

ZnS nanoarchitectures have been intensively investigated recently because of their applications in optoelectronics and adsorption capacity. The potential hazard of ZnS nanoarchitectures is not well known. In this study, we investigated the toxicity of ZnS nanoarchitectures on vascular endothelial cell (VEC) in vitro and in vivo. The results showed that ZnS could inhibit human umbilical vein endothelial cell (HUVEC) proliferation at 50 and 200 μg/mL. Endothelial nitric oxide synthase (eNOS) activity, nitric oxide (NO), and reactive oxygen species productions were increased, which was companied with the decrease in caveolin-1 level. The endothelium of the aortic root was damaged and the NO levels in serum were elevated in the mice treated with 5 or 10 mg/kg ZnS for 3 and 6 days, but the body could repair the damage. The data suggested that the high concentration of ZnS could induce dysfunction of VECs through decreasing caveolin-1 and elevation of the eNOS activity and thus present toxicity.
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http://dx.doi.org/10.1002/tox.21955DOI Listing
July 2015

Tunable surface charge of ZnS:Cu nano-adsorbent induced the selective preconcentration of cationic dyes from wastewater.

Nanoscale 2012 Jun 23;4(12):3665-8. Epub 2012 May 23.

State Key Laboratory of Structural Chemistry, Fujian Institute of Research on the Structure of Matter, Chinese Academy of Sciences, Fuzhou, Fujian 350002, China.

A novel environmentally friendly nano-adsorbent is developed by doping Cu(+) cations into the lattice of ZnS microspheres. The adsorbent shows selective adsorbability for cationic dyes in low concentrations in wastewater. The adsorbed dye could be successfully eluted with alcohol, resulting in a 1000 fold enrichment of the dye solution.
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http://dx.doi.org/10.1039/c2nr30689aDOI Listing
June 2012

Photocatalytic bactericidal mechanism of nanoscale TiO2 films on Escherichia coli.

J Nanosci Nanotechnol 2011 Sep;11(9):7621-6

State Key Lab of Structural Chemistry, Fujian Institute of Research on the Structure of Matter, Chinese Academy of Sciences, Fuzhou, Fujian 350002, China.

Two kinds of nanoscale TiO2 films were prepared by magnetron sputtering and screen printing methods, respectively. Results show that both phase composition and specific surface area of the film affect the photocatalytic bactericidal efficiency. Time-series in situ atomic force microscopy (AFM) observation were further used to characterize the cellular responses of Escherichia coli (E. coli) in photocatalytic process. Some nanosized patches were found on the bacterial surface in the forepart of photocatalytic reaction. It suggested that the photocatalytic attack induced the self-protection of bacteria at first. Subsequently, some cracks on the surface and the enlargement of cell body indicated that the cell wall was damaged and lost its structure supporting function, and it eventually led to the death of bacteria.
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http://dx.doi.org/10.1166/jnn.2011.4757DOI Listing
September 2011

Evaluation of phase, microstructure and composition of human dentine after Er,Cr:YSGG laser irradiation.

J Nanosci Nanotechnol 2011 Mar;11(3):2421-6

College of Stomatology, Fujian Medical University, Fuzhou, Fujian 350002, China.

This study aims to evaluate the composition, micro-structure and inorganic phase alternations of human dentine irradiated by Er,Cr:YSGG laser with water cooling spray system. X-ray diffraction (XRD) analysis indicated that the main inorganic phase of dentine before and after laser irradiation were all Hydroxyapatite (HA) structure, approximately 30 nm in size. No significant changes occurred in the average particle size after irradiation in four energy densities (6.18 J/cm2, 8.04 J/cm2, 9.89 J/cm2, 11.1 J/cm2). Atomic force microscope (AFM) phase image and the energy-dispersive spectroscope (EDS) analysis, however, demonstrated that the thermal effects of Er,Cr:YSGG laser with water-cooling spray system on the dentin surface was intense enough to induce notable decrease of the organic matter. Both scanning electron microscopy (SEM) and AFM analysis showed that the irradiated dentine presented rough surface morphology. The surface is clean and dentinal tubules are completely open. The ablation rate of both peri- and intertubular dentine increased at higher energy densities but no significant changes of gross appearance took place. Chemical analysis reveals that laser photothermal effect would decrease significantly the organic content of superficial dentinal layer. We conclude that the Er,Cr:YSGG laser, as a new type clinic laser, would not significantly influence the inorganic phase structure of the surface dentine layer, however, thermal ablation was occurred in organic component. Moreover, the rough ablated surface as well as the opened dentinal tubules induced by irradiation, might be advantageous to the infiltration of the adhesive materials, thus the adhesion of dental restoration could be enhanced. Further studies should focus on the correlation between bond strength and Er,Cr:YSGG lased dentine.
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http://dx.doi.org/10.1166/jnn.2011.3526DOI Listing
March 2011

Synthesis and characterization of nanocrystalline gaN by ammonothermal method using CsNH2 as mineralizer.

J Nanosci Nanotechnol 2010 Sep;10(9):5741-5

Key Laboratory of Optoelectronic Materials Chemistry and Physics, Fujian Institute of Research on the Structure of Matter, Chinese Academy of Sciences, Fuzhou, 350002, China.

Nanocrystalline GaN was ammonothermally synthesized at 430 degrees C with CsNH2 as mineralizer. X-ray powder diffraction (XRD) analysis showed that the nanocrystalline GaN were of hexagonal structure. The average diameter of nanocrystalline GaN was about 4.5 nm according to Scherer's formula using the full-width at half-maximum (FWHM) of the (110) peak. Transmission electron microscopy (TEM) and selected area electron diffraction (SAED) observation confirmed the size distribution and phase state of the GaN nanocrystals. The calculated lattice parameters obtained both from XRD and High-Resolution Transmission Electron Microscopy (HRTEM) were a = 3.197 A, c = 5.195 A, which were larger than the highly crystallized GaN bulk crystal. Room temperature photoluminescence (PL) measurement exhibited a weak band-edge emission at about 390 nm (3.18 eV), indicating an obvious red-shift from the bandgap of bulk GaN (3.39 eV). A green luminescence (GL) emission located at 485 nm (2.56 eV) and a yellow luminescence (YL) defect-related emission peak centered at 553 nm (2.24 eV) were also observed. The advantage of using CsNH2 as mineralizer for growth GaN, the possible origins of the red-shift of bandgap, YL and GL band were discussed. The red-shift of the bandgap of the as-synthesized GaN nanocrystals was possibly attributed to the expansion of lattice parameters.
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http://dx.doi.org/10.1166/jnn.2010.2460DOI Listing
September 2010

ZnS nano-architectures: photocatalysis, deactivation and regeneration.

Nanoscale 2010 Oct 5;2(10):2062-4. Epub 2010 Aug 5.

Key Laboratory of Optoelectronic Materials Chemistry and Physics, Fujian Institute of Research on the Structure of Matter, Chinese Academy of Sciences, Fuzhou, Fujian 350002, China.

An "infinite recycling" method for enhancing the durable applications of a ZnS nano-photocatalyst is shown. Based on the finding of thermodynamic stable nanophase of ZnS, we designed a strategy in which the deactivated ZnS nano-photocatalyst could be recovered into its original state. This ZnS photocatalyst can be used repeatedly without being released into environment as nano-waste. The strategy uses material highly efficiently and is environmentally friendly.
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http://dx.doi.org/10.1039/c0nr00171fDOI Listing
October 2010

Ultraviolet-light-induced bactericidal mechanism on ZnO single crystals.

Chem Commun (Camb) 2009 Nov 29(44):6783-5. Epub 2009 Sep 29.

Key Laboratory of Optoelectronic Materials Chemistry and Physics, Fujian Institute of Research on the Structure of Matter, Chinese Academy of Sciences Fuzhou, Fujian, 350002, China.

By comparing the photocatalytic bactericidal effect on different crystal faces of bulk ZnO crystal, we found that an electron degradation mechanism dominates the photocatalytic processes of ZnO material.
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http://dx.doi.org/10.1039/b912137dDOI Listing
November 2009

NaOH concentration effect on the oriented attachment growth kinetics of ZnS.

J Phys Chem B 2007 May 24;111(19):5290-4. Epub 2007 Apr 24.

State Key Lab of Structural Chemistry, Fujian Institute of Research on the Structure of Matter, Chinese Academy of Sciences, Fuzhou, Fujian, 350002, People's Republic of China.

In this work, the crystal growth kinetics of ZnS nanoparticles coarsened under 100 degrees C with NaOH concentration from 2 to 8 M was investigated, aiming to study the role of NaOH concentration on the oriented attachment growth kinetics. It reveals that 2 M NaOH is sufficient to lead to two-stage growth kinetics of ZnS nanoparticles, resulting in pure and multistep oriented attachment growth characteristics in the first stage. When the NaOH concentration increases, the rate of crystal growth by oriented attachment mechanism increases, while the time period for crystal growth at the pure oriented attachment stage was similar. We suggest that the concentration of solute is critical to enhance the oriented attachment growth rate and achieve exclusively oriented attachment growth of nanoparticles at a large size scale.
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http://dx.doi.org/10.1021/jp0688613DOI Listing
May 2007

Oriented attachment kinetics for ligand capped nanocrystals: coarsening of thiol-PbS nanoparticles.

J Phys Chem B 2007 Feb;111(6):1449-54

State Key Lab of Structural Chemistry, Fujian Institute of Research on the Structure of Matter, Chinese Academy of Sciences, Fuzhou, Fujian 350002, People's Republic of China.

In this work, the growth kinetics of thiol-capped PbS nanoparticles was studied. Two-stage growth process was observed, which was controlled first by oriented attachment (OA) mechanism and then by the hybrid Ostwald ripening (OR) and OA mechanism. Different from the NaOH-ZnS system, where OA will occur between any two multilevel nanoparticles, an OA kinetic model only considering the attachment related to original particles was fitted well with the experimental results. Analysis reveals that this model may be a universal one to describe the OA crystal growth process of nanocrystals capped with easily destroyed ligands, such as thiol-ZnS in the previous report. The OA crystal growth characteristics determined by the surface agent were discussed and compared. We propose that with stronger surface capping, the OR growth of nanocrystals is hindered, which facilitates the size controlling via OA kinetics during nanosynthesis.
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http://dx.doi.org/10.1021/jp067040vDOI Listing
February 2007

A multistep oriented attachment kinetics: coarsening of ZnS nanoparticle in concentrated NaOH.

J Am Chem Soc 2006 Oct;128(39):12981-7

State Key Lab of Structural Chemistry, Fujian Institute of Research on the Structure of Matter, National Engineering Research Center for Optoelectronic Crystalline Materials, Chinese Academy of Sciences, Fuzhou, Fujian 350002, People's Republic of China.

Crystal growth of ZnS nanoparticles during hydrothermal coarsened in 4 M NaOH occurs via a two-stage process. In the first stage, the primary particles grow into a size over hundred times of the original volume. The initial growth rate can be fitted by an asymptotic curve. High-resolution transmission electron microscope (HRTEM) data indicate that in this stage, crystal growth mainly occurs via a multistep crystallographically specific oriented attachment (OA). The higher the coarsening temperature, the earlier the first stage ends. In the second stage, an abrupt transition from asymptotic to square parabola growth kinetics occurs. The crystal growth data can be fitted by a standard Ostwald ripening (OR) model consistent with growth controlled by dissolution/precipitation of ions in solution. HRTEM data indicate that a minor amount of OA-based growth also occurs in the early period of the second stage. A new multistep OA kinetics model analogous to the reaction between molecules was proposed to illustrate the asymptotic growth in the first stage of coarsening. The effect of concentrated NaOH was discussed and proved to be the key that hindered the OR process, attributing to the almost exclusive pure OA-based growth of ZnS particles in the first stage.
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http://dx.doi.org/10.1021/ja062572aDOI Listing
October 2006
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