Dacheng He

Development of Proteomic Patterns for Detecting Lung Cancer

Lung cancer is at present the number one cause of cancer death and no biomarker is available to detect early lung cancer in serum samples so far. The objective of this study is to find specific biomarkers for detection of lung cancer using Surface Enhanced Laser Desorption/Ionization (SELDI) technology. In this study, serum samples from 30 lung cancer patients and 51 age-and sex-matched healthy were analyzed by SELDI based ProteinChip reader, PBSII-C. The spectra were generated on WCX2 chips and protein peaks clustering and classification analyses were performed utilizing Biomarker Wizard and Biomarker Patterns software packages, respectively. Three protein peaks were automatically chosen for the system training and the development of a decision classification tree. The constructed model was then used to test an independent set of masked serum samples from 15 lung cancer patients and 31 healthy individuals. The analysis yielded a sensitivity of 93.3%, and a specificity of 96.7%. These results suggest that the serum is a capable resource for detection of specific lung cancer biomarkers. SELDI technique combined with an artificial intelligence classification algorithm can both facilitate the discovery of better biomarkers for lung cancer and provide a useful tool for molecular diagnosis in future.

Distinguish cancer cells based on targeting turn-on fluorescence imaging by folate functionalized green emitting carbon dots

Developing efficient methods for visual detection of cancer cells has the potential to contribute greatly to basic biological research and early diagnosis of cancer. Here, we report facile and one-step synthesis of green fluorescence carbon dots (CDs) with the help of a new passivating agent--poly(acrylate sodium) (PAAS). Based on the as-prepared CDs, a novel turn-on fluorescence probe was designed for targeting imaging of cancer cells via hydrogen-bond interaction between folic acid and CDs (FA-CDs). Intracellular experiments indicated that FA-CDs probe could accurately distinguish folate receptor (FR)-positive cancer cells in different cell mixtures with turn-on mode. In particular, combining the targeting of FA-CDs probe with the excellent photostability of CDs has inestimable meaning for fluorescence-assisted surgical resection and acquisition real-time information about tumor cells. Obviously, the as-prepared FA-CDs probe may have great potential as a high-performance platform for accurately recognizing special cancer cells, which may provide new tools for cancer prognosis and therapy.

Reduced transthyretin expression in sera of lung cancer

Lung cancer is a leading cause of cancer death worldwide, and very few specific biomarkers can be used in its clinical diagnosis. Using surface‐enhanced laser desorption–ionization time‐of‐flight mass spectrometry (MS) to find novel serum biomarkers for lung cancer, we analyzed 227 serum samples, including 146 lung cancers, 41 benign lung diseases and 40 normal individuals. Three peaks, at 13.78, 13.90 and 14.07 k m/z, were significantly lower in lung cancer sera compared with sera from normal individuals (P < 0.001), whereas these peaks were higher than those in the sera of benign lung diseases (P < 0.001). The peaks were identified as native transthyretin (TTR) and its two variants by one‐dimensional polyacrylamide gel electrophoresis, ESI‐MS/MS, immunoprecipitation and western blot analysis. An enzyme‐linked immunosorbent assay indicated that TTR levels were consistent with surface‐enhanced laser desorption–ionization analysis in all groups tested. It gave 78.5% sensitivity and 77.5% specificity for lung cancer versus normal at the cut‐off point 115 µg/mL, and 66.7% sensitivity and 64.4% specificity for lung cancer versus benign lung diseases at the cut‐off point 88.5 µg/mL. Therefore, TTR may be useful as a biomarker to improve the diagnosis of lung cancer. (Cancer Sci 2007; 98: 1617–1624)

Sequence‐Dependent dsDNA‐Templated Formation of Fluorescent Copper Nanoparticles

There are only a few systematic rules about how to selectively control the formation of DNA-templated metal nanoparticles (NPs) by varying sequence combinations of double-stranded DNA (dsDNA), although many attempts have been made. Herein, we develop a facile method for sequence-dependent formation of fluorescent CuNPs by using dsDNA as templates. Compared with random sequences, AT sequences are better templates for highly fluorescent CuNPs. Other specific sequences, for example, GC sequences, do not induce the formation of CuNPs. These results shed light on directed DNA metallization in a sequence-specific manner. Significantly, both the fluorescence intensity and the fluorescence lifetime of CuNPs can be tuned by the length or the sequence of dsDNA. In order to demonstrate the promising practicality of our findings, a sensitive and label-free fluorescence nuclease assay is proposed.

A fluorescent aptasensor for amplified label-free detection of adenosine triphosphate based on core-shell Ag@SiO2 nanoparticles.

The novel, facile and universal aptamer-based methods for the highly sensitive and selective fluorescence detection of important biomolecules have attracted considerable interest. Here, we present a label-free aptasensor for adenosine triphosphate (ATP) detection in aqueous solutions by using an ultra-sensitive nucleic acid stain PicoGreen (PG) as a fluorescent indicator and core-shell Ag@SiO2 nanoparticles (NPs) as a metal-enhanced fluorescence (MEF) platform. In the presence of ATP, the complementary DNA (cDNA)/aptamer duplexes confined onto the Ag@SiO2 NPs surface can release their aptamers into the buffered solution, causing a significant reduction in fluorescence intensity. By virtue of the amplified fluorescence signal, this aptasensor toward ATP can achieve a detection limit of 14.2 nM with a wide linear range and exhibit a good assay performance in complex biological samples. This sensing approach is cost-effective and efficient because it avoids the fluorescence labeling process and the use of any enzymes. Hence, this method may offer an alternative tool for determining the concentrations of ATP in biochemical and biomedical research.

Multifunctional core–shell upconversion nanoparticles for targeted tumor cells induced by near-infrared light

Here we synthesize silica-coated NaYF4:Yb/Er nanocomposites with a photosensitizer hypericin covalently bound to silica shells (UCNPs@SiO2@hypericin) successfully, exhibiting precise size-control, good water dispersity and excellent biocompatibility. Under near-infrared light (NIR) irradiation, UCNPs convert NIR light to strong green light which agrees well with the absorbance peak of the photosensitizer hypericin, and triggers hypericin to generate singlet oxygen effectively. The cell apoptosis studies by flow cytometry, fluorescence microscope imaging with Annexin V-FITC/PI and caspase-3 western blotting demonstrate that UCNPs@SiO2@hypericin-FA displays outstanding performance in the induction of apoptosis of Hela cells and HepG2 cells under NIR light irradiation for a short time. At the same time, UCNPs@SiO2@hypericin-FA nanocomposites are proved to exhibit little cytotoxicity by cell viability experiments. By the use of confocal microscopy, cell uptake results show that folate receptor FR(+) cell lines such as Hela cells could internalize more UCNPs@SiO2@hypericin-FA than FR(-) cell lines, such as 293T cells, with highly selective cellular uptake. All the results indicate that UCNPs@SiO2@hypericin-FA nanocomposites have a promising potential in the application of PDT and other diseases in deep tissues.

Serum levels of variants of transthyretin down‐regulation in cholangiocarcinoma

Cholangiocarcinoma (CC) is devastating neoplasm and very few specific biomarkers could be used in clinical diagnosis. A study was taken to find novel serum biomarkers for CC.

Solvatochromism, Reversible Chromism and Self‐Assembly Effects of Heteroatom‐Assisted Aggregation‐Induced Enhanced Emission (AIEE) Compounds

Two compounds, 9,10-bis[2-(quinolyl)vinyl]anthracene (BQVA) and 9,10-bis[2-(naphthalen-2-yl)vinyl]anthracene (BNVA), have been synthesised and investigated. Both of them have aggregation-induced enhanced emission (AIEE) properties. Heteroatom-assisted BQVA shows solvatochromism, reversible chromism properties and self-assembly effects. When increasing the solvent polarities, the green solution of BQVA turns to orange with a redshift of the fluorescence emission wavelengths from λ=527 to 565 nm. Notably, BQVA exhibits reversible chromism properties, including mechano- and thermochromism. The as-prepared BQVA powders show green fluorescence (λem=525 nm) and the colour can turn into orange (λem=573 nm) after grinding. Interestingly, the orange colour can return at high temperature. Based on these reversible chromism properties, a simple and convenient erasable board has been designed. Different from BQVA, non-heteroatom-assisted BNVA has no clear chromic processes. The results obtained from XRD, differential scanning calorimetry, single-crystal analysis and theoretical calculations indicate that the chromic processes depend on the heteroatoms in BQVA. Additionally, BQVA also exhibits excellent self-assembly effects in different solvents. Homogeneous nanospheres are formed in mixtures of tetrahydrofuran and water, which are then doped into silica nanoparticles and treated with 3-aminopropyltriethoxysilane to give amino-functionalised nanoparticles (BQVA-AFNPs). The BQVAAFNPs could be used to stain protein markers in polyacrylamide gel electrophoresis.

Application of fluorescent carbon nanodots in fluorescence imaging of human serum proteins

In our studies, fluorescent carbon nanodots (C-dots) imaging was established for the on gels-detection of human serum proteins and Escherichia coli proteins after polyacrylamide gel electrophoresis (PAGE). The water-soluble C-dots were synthesized by a one-step microwave pyrolysis method, and emit bright, stable luminescence at 450 nm. For imaging, the fluorescent C-dots solution acted as the direct incubating solution, which was diluted with acetic acid (pH 2.7). After staining, fluorescence signals of proteins in the gel were obtained by ultraviolet illumination at 365 nm. The sensitivity of C-dots imaging was evaluated by the comparison of the signal intensities of transferrin obtained by different imaging methods, which resulted in 8 times higher sensitivity than the traditional CBB-R250 staining. Identified by mass spectrometry (MS), some proteins such as isoform 1 of alpha-1-antichymotrypsin (ACT), zinc-alpha-2-glycoprotein (ZAG) and complement C3 (fragment), can be easily detected by C-dots imaging after 2-D PAGE. However, they could not be detected by CBB-R250 staining. As a new fluorescence method for protein detection, C-dots imaging is simple, fast and sensitive, showing potential for proteome research.

Multifunctional up-converting nanocomposites with multimodal imaging and photosensitization at near-infrared excitation

Here we report the synthesis of silica coated NaYF4:Yb/Tm nanocomposites, with a covalent coating of 1,8-dihydroxy-3-methylanthraquinone (DHMA), which has high ability to produce reactive oxygen species (ROS) and fluorescein isothiocyanate (FITC) for downconverting imaging. Upon excitation by near-infrared light, the nanocomposites convert lower-energy light to higher-energy light, which will trigger DHMA to generate ROS and consequently kill the folate receptor (FR) (+) tumor cells. The apoptosis effect of tumor cells induced by the as-prepared nanocomposites [UCNP@(DHMA/FITC)@SiO2–FA] was proven by fluorescence microscope imaging after staining with Annexin V-FITC/PI, Caspase-3 Western blotting, flow cytometry assay and cell viability assay. The results indicated that the as-prepared nanocomposites can effectively induce apoptosis in HeLa and HepG2 cells and the percentage of early apoptosis in tumor cells is as high as 42.75%. In addition, the photosensitive efficiency of DHMA covalent coating nanocomposites [UCNP@(DHMA/FITC)@SiO2–FA] is higher than that of DHMA simply deposited nanocomposites [UCNP@SiO2(DHMA/FITC)–FA]. As a result, high photosensitivity and selectivity are achieved in tumor cells upon incubation with the nanocomposites and exposure to an NIR laser. Furthermore, multimodal fluorescence labelling is also achieved with good photostability and no background noise. Therefore, they will potentially be useful either as PDT drugs or multimodal luminescent probes in bioimaging.