Hongwu Du

Space-confined fabrication of silver nanodendrites and their enhanced SERS activity

Here we report a controllable method based on electrodeposition to fabricate Ag nanodendrites (NDs) on a microwell patterned electrode. The microwell patterns on the ITO electrode are fabricated via the microcontact printing technique. By varying the microwell size and electrodeposition time, the morphology of metal deposits on the microwell patterned ITO electrode can be tuned from boulders to dendrites. At the edge of the microwells, the current density was strengthened, which incurs rapid nucleation. The nucleus develops into dendrites because of Mullins-Sekerka instability. However, only boulders were observed at the center of microwells. By reducing the size of the microwells, only NDs were fabricated due to the edge effect. On the basis of understanding the underlying mechanism for dendritic growth in a confined space, our method is used for fabricating other noble metal (Au, Pt) nanodendrites. The controllable synthesis of Au and Pt NDs indicates the universality of this method. Compared with Ag film obtained from electron beam evaporation, the as-prepared Ag NDs exhibit highly enhanced surface-enhanced Raman scattering (SERS) sensitivity when they are used to detect rhodamine 6G (R6G). This approach provides a very controllable, reliable and general way for space-confined fabricating the noble metal nanodendrite arrays which show great promise in catalysis, sensing, biomedicine, electronic and magnetic devices.

Highly efficient remote controlled release system based on light-driven DNA nanomachine functionalized mesoporous silica

An intelligent photoswitchable single-molecule nanomachine with DNA hairpin-loop structure was designed by the incorporation of azobenzene groups in DNA sequences, which was studied by fluorescence resonance energy transfer (FRET) and attached onto the surface of mesoporous silica. Based on the photo-induced conformational transformation of DNA, highly efficient controlled release was realized.

A Selective Release System Based on Dual‐Drug‐Loaded Mesoporous Silica for Nanoparticle‐Assisted Combination Therapy

A selective release system was demonstrated with a dual-cargo loaded MSNs. When stimulated by different signals (UV or H(+)), this system could selectively release different kinds of cargoes individually. Furthermore, this system has been used to provide a combination of chemotherapy and biotherapy for cancer treatment. This controlled release system could be an important step in the development of more effective and sophisticated nanomedicine and nanodevices, due to the possibility of selective release of a complex multi-drug.

Generation and evaluation of antibodies against human MGF E-peptide by reverse phase protein microarray and reverse competitive ELISA

BACKGROUND Since 2005, as one of prohibited substances on the Prohibited List of the World Anti-Doping Agency (WADA), the occurence of mechano growth factor (MGF) abuse in sport has likely increased. However, there is still no WADA-validated and -approved method for its detection. RESULTS Four polyclonal antibodies (Ab-K01, Ab-B01, Ab-B02 and Ab-K02) against MGF C-terminal peptides were generated, purified and evaluated by western blot, ELISA and reverse-phase protein microarray, respectively. It was found that all the antibodies could identify their corresponding antigen in mouse serum by reverse-phase protein microarray, in particular, Ab-K01 showed the highest affinity among them and might be a potential tool for the detection of antibody affinity. Furthermore, Ab-B01 and Ab-K01 were successfully used for the determination of MGF-40 by reverse competitive ELISA. CONCLUSION The quantitative measurement of MGF-40 has laid the foundation for doping detection of MGF and further biological research on MGF.

Prohibitin Is Involved in Patients with IgG4 Related Disease

Objective IgG4-related disease (IgG4-RD) is a chronic systemic disease involved in many organs and tissues. As only limited autoantigens have been found since the beginning of this century, the aim of this study was to reveal new candidate autoantigens of IgG4-RD. Methods Multiple cell lines including HT-29, EA.hy926, HEK 293 and HepG2 were used to test the binding ability of circulating autoantibodies from IgG4-RD sera. The amino-acid sequence was then analyzed by matrix-assisted laser desorption/ionization time-of-flight tandem (MALDI-TOF/TOF) mass spectrometry. After the cloning and expression of recombinant putative autoantigen in a bacterial expression system, the corresponding immuno assay was set up and utilized to observe the prevalence of serum autoantibodies in a large set of confirmed clinical samples. Results One positive autoantigen was identified as prohibitin. ELISA analysis showed that a majority of patients with IgG4-RD have antibodies against prohibitin. Anti-prohibitin antibodies were present in the sera of patients with definite autoimmune pancreatitis (25/34; 73.5%), Mikulicz’s disease (8/15; 53.3%), retroperitoneal fibrosis (6/11; 54.5%), other probable IgG4-RD (26/29; 89.7%) and Sjögren’s syndrome (4/30; 13.3%) but not in apparently healthy donors (1/70; 1.4%). Conclusions An association between prohibitin and patients with some IgG4-RD was observed, although the results were quite heterogeneous among different individuals within autoimmune pancreatitis, Mikulicz’s disease and retroperitoneal fibrosis.

Pathway for Biodegrading Microcystin-YR by Sphingopyxis sp.USTB-05

Harmful cyanobacterial blooms in waters have become a global environmental problem, this mainly due to the production and release of various microalgal toxins, in which microcystins (MCs) are distributed widely. Here, we focused on the study of a typical form of microcystins called microcystin-YR (MC-YR). It was found that initial 14.8 mg/L of MC-YR could be completely eliminated within 10 hr by the crude enzymes (CEs) of Sphingopyxis sp. USTB-05, a promising bacterial strain we isolated and identified in our previous study. During the enzymatic biodegradation of MC-YR with time course, the peaks of two intermediate and two final products were observed on the profiles of HPLC at the wavelengths of 238 nm and 230 nm, respectively. Based on the analysis of m/z ratios of MC-YR and its four products by LC-MS/MS, we suggested that at least four enzymes were involved in the biodegradation of MC-YR by Sphingopyxis sp. USTB-05. The first enzyme microcystinase converted cyclic MC-YR to linear MC-YR as the first product. Then the second enzyme serine protease was found to cleave the target peptide bond between alanine (Ala) and tyrosine (Tyr) of linearized MC-YR, producing a tetrapeptide and a tripeptide as second products, which were Adda-Glu-Mdha-Ala and Tyr-Masp-Arg, respectively. Next, the third enzyme peptidase converted the tetrapeptide of Adda-Glu-Mdha-Ala to Adda. And the fourth enzyme cleaved the tripeptide of Tyr-Masp-Arg to produce Tyr and dipeptide (Masp-Arg), which has never been reported. These findings will help us better understand the biodegradation pathway of MC-YR by Sphingopyxis sp. USTB-05.

A free-blockage controlled release system based on the hydrophobic/hydrophilic conversion of mesoporous silica nanopores.

A pH-responsive free-blockage release system was achieved through controlling the hydrophobic/hydrophilic conversion of mesoporous silica nanopores. This system further presented pulsatile release with changing pH values between 4.0 and 7.0 for several cycles. This free-blockage release system could also release antitumor agents to induce cell death after infecting tumor cells and could have the ability of continuous infection to tumor cells with high drug-delivery efficiency and few side effects.

Identification of heat shock protein 27 as a novel autoantigen of Behçet’s disease

OBJECTIVE The aim of this study was to identify candidate pathogenic autoantigens of Behçets disease (BD) in pathogen-stimulated target cells. METHODS First, three cell lines were used as target cells to screen autoantibody. Second, selected target cells were simulated with pathogens. Third, western blotting was used for detecting the auto-antigens in cell extracts. Next, immunoprecipitation was performed and the amino-acid sequences of target antigens were analyzed by LC-MALDI-TOF/TOF. Then, the potential target antigen was expressed, purified, and immunologically confirmed. And finally, an ELISA kit was developed and clinically validated through the assessments of 456 clinical samples with BD. RESULTS One antigen with a molecular weight of approximately 27-kDa was identified as heat shock protein 27 (HSP27). The reactivity of serum IgG against recombinant human HSP27 was detected in 52 of 91 BD patients (57%), 66 of 92 rheumatoid arthritis (RA) patients (72%), 32 of 90 Sjogren syndrome (SS) patients (36%), 22 of 92 systemic lupus erythematosus (SLE) patients (24%) and 0 of 91 healthy controls (HC). The reactivity of BD serum IgG antibodies against HSP27 was significantly higher than SLE (P<0.0001) SS (P<0.0001) and HC (P<0.0001). CONCLUSIONS This study identified HSP27 as a candidate endothelial cell autoantigen of BD, which is interesting and probably worth further exploration.

A Versatile Multiple Target Detection System Based on DNA Nano-assembled Linear FRET Arrays

DNA molecules have been utilized both as powerful synthetic building blocks to create nanoscale architectures and as inconstant programmable templates for assembly of biosensors. In this paper, a versatile, scalable and multiplex detection system is reported based on an extending fluorescent resonance energy transfer (FRET) cascades on a linear DNA assemblies. Seven combinations of three kinds of targets are successfully detected through the changes of fluorescence spectra because of the three-steps FRET or non-FRET continuity mechanisms. This nano-assembled FRET-based nanowire is extremely significant for the development of rapid, simple and sensitive detection system. The method used here could be extended to a general platform for multiplex detection through more-step FRET process.

Electron Transfer Flavoprotein Subunit Beta Is a Candidate Endothelial Cell Autoantigen in Behçet’s Disease

Behçet’s disease (BD) is a chronic inflammatory disease with multisystem involvement, and it is listed as a rare disease in the United States but is common in the Middle East, China, and Japan. The aim of this study was to identify novel autoantigens in Chinese patients with BD. First, the candidate autoantigens were screened by Western blotting, and the sequences of putative antigens were identified by LC-MALDI-TOF/TOF mass spectrometry. Next, the screened protein was cloned, expressed and purified. Then, an optimized ELISA was developed, and the serological criteria were evaluated using a large number of confirmed patients. One antigen with a molecular weight of approximately 28 kDa was identified as electron transfer flavoprotein subunit beta (ETFB). Positive reactivity was detected in recombinant human ETFB sera from 38 of 92 BD patients (41 %) and 1 of 90 healthy controls (1 %).