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Wu T.,School and Hospital of Stomatology | Cheng N.,University of North Carolina at Chapel Hill | Xu C.,Australian Institute for Bioengineering and Nanotechnology AIBN | Sun W.,Wuhan UniversityWuhan430079 Peoples Republic of China | And 2 more authors.
Journal of Biomedical Materials Research - Part A | Year: 2016

This study evaluated the effect of mesoporous bioglass (MBG) dissolution on the differentiation of bone marrow mesenchymal stem cells (BMSCs) derived from either sham control or ovariectomized (OVX) rats. MBG was fabricated by evaporation-induced self-assembly method. Cell proliferation was tested by Cell Counting Kit-8 assay, and cytoskeletal morphology was observed by fluorescence microscopy. Osteogenic differentiation was evaluated by alkaline phosphatase (ALP) staining and activity, Alizarin Red staining, while adipogenic differentiation was assessed by Oil Red-O staining. Quantitative real-time PCR and Western blot analysis were taken to evaluate the expression of runt-related transcription factor 2 (Runx2) and proliferator-activated receptor-γ (PPARγ). We found that MBG dissolution (0, 25, 50, 100, 200 μg/mL) was nontoxic to BMSCs growth. Sham and OVX BMSCs exhibited the highest ALP activity in 50 μg/mL of MBG osteogenic dissolution, except that sham BMSCs in 100 μg/mL showed the highest ALP activity on day 14. Runx2 was significantly upregulated after 100 μg/mL of MBG stimulation in sham and OVX BMSCs for 7 and 14 days, except that 25 μg/mL showed highest upregulation effect on OVX BMSCs at day 7. PPARγ was downregulated after MBG stimulation. The protein level of Runx2 from the sham BMSCs group was significantly upregulated after lower doses (25 and 50 μg/mL) of MBG stimulation, whereas PPARγ was downregulated in the sham and OVX BMSCs group. Thus, both the osteogenic and adipogenic abilities of BMSCs were damaged under OVX condition. Moreover, lower concentration of MBG dissolution can promote osteogenesis but inhibit adipogenesis of the sham and OVX BMSCs. © 2016 Wiley Periodicals, Inc.


Wang Y.,Australian Institute for Bioengineering and Nanotechnology AIBN | Wang Y.,University of Duisburg - Essen | Rauf S.,Australian Institute for Bioengineering and Nanotechnology AIBN | Grewal Y.S.,Australian Institute for Bioengineering and Nanotechnology AIBN | And 6 more authors.
Analytical Chemistry | Year: 2014

Quantitative and accurate detection of multiple biomarkers would allow for the rapid diagnosis and treatment of diseases induced by pathogens. Monoclonal antibodies are standard affinity reagents applied for biomarkers detection; however, their production is expensive and labor-intensive. Herein, we report on newly developed nanoyeast single-chain variable fragments (NYscFv) as an attractive alternative to monoclonal antibodies, which offers the unique advantage of a cost-effective production, stability in solution, and target-specificity. By combination of surface-enhanced Raman scattering (SERS) microspectroscopy using glass-coated, highly purified SERS nanoparticle clusters as labels, with a microfluidic device comprising multiple channels, a robust platform for the sensitive duplex detection of pathogen antigens has been developed. Highly sensitive detection for individual Entamoeba histolytica antigen EHI115350 (limit of detection = 1 pg/mL, corresponding to 58.8 fM) and EHI182030 (10 pg/mL, corresponding 453 fM) with high specificity has been achieved, employing the newly developed corresponding NYscFv as probe in combination with SERS microspectroscopy at a single laser excitation wavelength. Our first report on SERS-based immunoassays using the novel NYscFv affinity reagent demonstrates the flexibility of NYscFv fragments as viable alternatives to monoclonal antibodies in a range of bioassay platforms and paves the way for further applications. © 2014 American Chemical Society.


Wee E.J.H.,Australian Institute for Bioengineering and Nanotechnology AIBN | Rauf S.,Australian Institute for Bioengineering and Nanotechnology AIBN | Shiddiky M.J.A.,Australian Institute for Bioengineering and Nanotechnology AIBN | Dobrovic A.,Ludwig Institute for Cancer Research | And 3 more authors.
Clinical Chemistry | Year: 2015

Background: DNA methylation is a potential source of disease biomarkers. Typically, methylation levels are measured at individual cytosine/guanine (CpG) sites or over a short region of interest. However, regions of interest often show heterogeneous methylation comprising multiple patterns of methylation (epialleles) on individual DNA strands. Heterogeneous methylation is largely ignored because digital methods are required to deconvolute these usually complex patterns of epialleles. Currently, only singlemolecule approaches, such as next generation sequencing (NGS), can provide detailed epiallele information. Because NGS is not yet feasible for routine practice, we developed a single-molecule-like approach, named for epiallele quantification (EpiQ).Methods: EpiQ uses DNA ligases and the enhanced thermal instability of short (≤19 bases) mismatched DNA probes for the relative quantification of epialleles. The assay was developed using fluorescent detection on a gel and then adapted for electrochemical detection on a microfabricated device. NGS was used to validate the analytical accuracy of EpiQ.Results: In this proof of principle study, EpiQ detected with 90%-95% specificity each of the 8 possible epialleles for a 3-CpG cluster at the promoter region of the CDKN2B (p15) tumor suppressor gene. EpiQ successfully profiled heterogeneous methylation patterns in clinically derived samples, and the results were crossvalidated with NGS.Conclusions: EpiQ is a potential alternative tool for characterizing heterogeneous methylation, thus facilitating its use as a biomarker. EpiQ was developed on a gel-based assay but can also easily be adapted for miniaturized chip-based platforms. © 2014 American Association for Clinical Chemistry.


Du A.,Australian Institute for Bioengineering and Nanotechnology AIBN | Ng Y.H.,University of New South Wales | Bell N.J.,University of New South Wales | Zhu Z.,University of Queensland | And 2 more authors.
Journal of Physical Chemistry Letters | Year: 2011

We demonstrated for the first time by large-scale ab initio calculations that a graphene/titania interface in the ground electronic state forms a charge-transfer complex due to the large difference of work functions between graphene and titania, leading to substantial hole doping in graphene. Interestingly, electrons in the upper valence band can be directly excited from graphene to the conduction band, that is, the 3d orbitals of titania, under visible light irradiation. This should yield well-separated electron-hole pairs, with potentially high photocatalytic or photovoltaic performance in hybrid graphene and titania nanocomposites. Experimental wavelength-dependent photocurrent generation of the graphene/titania photoanode demonstrated noticeable visible light response and evidently verified our ab initio prediction. © 2011 American Chemical Society.


Wang Y.,Australian Institute for Bioengineering and Nanotechnology AIBN | Vaidyanathan R.,Australian Institute for Bioengineering and Nanotechnology AIBN | Shiddiky M.J.A.,Australian Institute for Bioengineering and Nanotechnology AIBN | Trau M.,Australian Institute for Bioengineering and Nanotechnology AIBN | Trau M.,University of Queensland
ACS Nano | Year: 2015

A rapid and simple approach is presented to address two critical issues of surface-enhanced Raman scattering (SERS)-based immunoassay such as removal/avoiding nonspecific adsorption and reducing assay time. The approach demonstrated involves rationally designed fluorophore-integrated gold/silver nanoshells as SERS nanotags and utilizes alternative current electrohydrodynamic (ac-EHD)-induced nanoscaled surface shear forces to enhance the capture kinetics. The assay performance was validated in comparison with hydrodynamic flow and conventional immunoassay-based devices. These nanoscaled physical forces acting within nanometer distances from the electrode surface enabled rapid (40 min), sensitive (10 fg/mL), and highly specific detection of human epidermal growth factor receptor 2 in breast cancer patient samples. We believe this approach presents potential for the development of rapid and sensitive SERS immunoassays for routine clinical diagnosis. © 2015 American Chemical Society.


Wang Y.,Australian Institute for Bioengineering and Nanotechnology AIBN | Wee E.J.H.,Australian Institute for Bioengineering and Nanotechnology AIBN | Trau M.,Australian Institute for Bioengineering and Nanotechnology AIBN | Trau M.,University of Queensland
Chemical Communications | Year: 2015

Sensitive and accurate DNA methylation analysis at CpG resolution was demonstrated using surface-enhanced Raman scattering (SERS) via ligase chain reaction (LCR). The method was sensitive to 10% changes in methylation and the accuracy of methylation estimates in cells and serum DNA validated with sequencing. The LCR/SERS approach may have broad applications as an alternative (epi)genetic detection method. © 2015 Royal Society of Chemistry.


Wang Y.,Australian Institute for Bioengineering and Nanotechnology AIBN | Wee E.J.H.,Australian Institute for Bioengineering and Nanotechnology AIBN | Trau M.,Australian Institute for Bioengineering and Nanotechnology AIBN | Trau M.,University of Queensland
Chemical Communications | Year: 2016

Sensitive and accurate total genomic DNA methylation analysis was demonstrated by surface-enhanced Raman scattering (SERS) via embedded internal SERS nanotags. The assay was sensitive to 0.2 ng input DNA while differentiating as low as 6.25% changes in DNA methylation. The method could also successfully differentiate cells before and after de-methylating drug-treatment and between tumor and normal biopsies. © The Royal Society of Chemistry 2016.


Wee E.J.H.,Australian Institute for Bioengineering and Nanotechnology AIBN | Rauf S.,Australian Institute for Bioengineering and Nanotechnology AIBN | Koo K.M.,Australian Institute for Bioengineering and Nanotechnology AIBN | Shiddiky M.J.A.,Australian Institute for Bioengineering and Nanotechnology AIBN | And 2 more authors.
Lab on a Chip - Miniaturisation for Chemistry and Biology | Year: 2013

Microfabricated devices for the electrochemical detection of single DNA base changes in cancer cell lines are highly desirable due to the inherent advantages such as portability, simplicity, and the rapid and inexpensive nature of electrochemical readout methods. Moreover, molecular sensors that use microscale-footprint working electrodes have shown high signal-to-noise ratio. Herein we report a microdevice-based electrochemical assay (μ-eLCR) measuring ligase chain reaction (LCR)-amplified long and short "knife" motifs which reflect the presence or absence of a DNA base change of interest in a target sequence. This μ-eLCR approach has higher sensitivity (4.4 to 10 fold improvement over macrodisk electrodes) and good reproducibility (%RSD 6.5%, n = 12) for the detection of LCR-amplified DNA bases. The devices also exhibited excellent sensitivity for the detection of DNA methylation (C to T base change in a locus associated with cancer metastasis) in two cell lines and serum derived DNA samples. We believe that the μ-eLCR device may be a useful diagnostic tool for inexpensive and rapid detection of single DNA base change applications such as DNA methylation and single nucleotide polymorphism (SNP) detection. © 2013 The Royal Society of Chemistry.


PubMed | Australian Institute for Bioengineering and Nanotechnology AIBN
Type: Journal Article | Journal: Chemical communications (Cambridge, England) | Year: 2016

Sensitive and accurate total genomic DNA methylation analysis was demonstrated by surface-enhanced Raman scattering (SERS) via embedded internal SERS nanotags. The assay was sensitive to 0.2 ng input DNA while differentiating as low as 6.25% changes in DNA methylation. The method could also successfully differentiate cells before and after de-methylating drug-treatment and between tumor and normal biopsies.


PubMed | Australian Institute for Bioengineering and Nanotechnology AIBN
Type: Journal Article | Journal: Chemical communications (Cambridge, England) | Year: 2015

Sensitive and accurate DNA methylation analysis at CpG resolution was demonstrated using surface-enhanced Raman scattering (SERS) via ligase chain reaction (LCR). The method was sensitive to 10% changes in methylation and the accuracy of methylation estimates in cells and serum DNA validated with sequencing. The LCR/SERS approach may have broad applications as an alternative (epi)genetic detection method.

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