Liping Jiang

Rapid sonochemical synthesis of highly luminescent non-toxic AuNCs and Au@AgNCs and Cu (II) sensing

Highly fluorescent and water-soluble gold nanoclusters (AuNCs) with near-infrared-emission and Au@AgNCs with yellow-emission were successfully prepared via a rapid sonochemical approach, and the as-prepared AuNCs could be applied in the determination of Cu(2+) with a wider detection range and lower detection limit.

Microwave-assisted synthesis of wavelength-tunable photoluminescent carbon nanodots and their potential applications.

A facile and rapid strategy was developed for the synthesis of ultrabright luminescent carbon nanodots (CDs) with tunable wavelength from 464 to 556 nm by introducing glutaraldehyde into the precursor solution under microwave irradiation. The fluorescence properties, including excitation and emission wavelength, quantum yield, and size of the CDs, were adjusted by changing the amount of glutaraldehyde and poly(ethylenimine). Several methods such as high-resolution transmission electron microscopy, X-ray photoelectron spectroscopy, and dynamic light scattering, UV-vis, fluorescence, and Fourier transform infrared spectroscopy were employed to study the morphology and the properties of CDs. The luminescence mechanism was also discussed. In addition, confocal microscopy imaging revealed that the as-prepared CDs could be used as effective fluorescent probes in the cell imaging without obvious cytotoxicity. Moreover, a novel sensor for the detection of Co(2+) was proposed on the basis of Co(2+)-induced fluorescence quenching. These superior properties demonstrated the potential application of the CDs in cellular imaging and ion sensing.

Electron Transfer Mediated Electrochemical Biosensor for MicroRNAs Detection Based on Metal Ion Functionalized Titanium Phosphate Nanospheres at Attomole Level

MicroRNAs (miRNAs) have emerged as new candidates as diagnostic and prognostic biomarkers for the detection of a wide variety of cancers; thus, sensitive and selective detection of microRNAs is significant for early-phase cancer diagnosis and disease prevention. A novel and simple electrochemical miRNA biosensor was developed using Cd(2+)-modified titanium phosphate nanoparticles as signal unit, two DNA as capture probes, and Ru(NH3)6(3+) as electron transfer mediator. Large quantities of cadmium ions were mounted in titanium phosphate spheres to output the electrochemical signal. Because of the presence of Ru(NH3)6(3+) molecules that interacted with DNA base-pairs as electron wire, the electrochemical signal significantly increased more than 5 times. This approach achieved a wide dynamic linear range from 1.0 aM to 10.0 pM with an ultralow limit detection of 0.76 aM, exerting a substantial enhancement in sensitivity. Moreover, the proposed biosensor was sufficiently selective to discriminate the target miRNAs from homologous miRNAs and could be used for rapid and direct analysis of miRNAs in human serum. Therefore, this strategy provides a new and ultrasensitive platform for miRNA expression profiling in biomedical research and clinical diagnosis.

FITC Doped Rattle-Type Silica Colloidal Particle-Based Ratiometric Fluorescent Sensor for Biosensing and Imaging of Superoxide Anion

Fluorescent nanosensors have been widely applied in recognition and imaging of bioactive small molecules; however, the complicated surface modification process and background interference limit their applications in practical biological samples. Here, a simple, universal method was developed for ratiometric fluorescent determination of general small molecules. Taking superoxide anion (O2(•-)) as an example, the designed sensor was composed of three main moieties: probe carrier, rattle-type silica colloidal particles (mSiO2@hmSiO2 NPs); reference fluorophore doped into the core of NPs, fluorescein isothiocyanate (FITC); fluorescent probe for superoxide anion, hydroethidine (HE). In the absence of O2(•-), the sensor just emitted green fluorescence of FITC at 518 nm. When released HE was oxidized by O2(•-), the oxidation product exhibited red fluorescence at 570 nm and the intensity was linearly associated with the concentration of O2(•-), while that of reference element remained constant. Accordingly, ratiometric determination of O2(•-) was sensitively and selectively achieved with a linear range of 0.2-20 μM, and the detection limit was calculated as low as 80 nM. Besides, the technique was also successfully applied for dual-emission imaging of O2(•-) in live cells and realized visual recognition with obvious fluorescence color change in normal conditions or under oxidative stress. As long as appropriate reference dyes and sensing probes are selected, ratiometric biosensing and imaging of bioactive small molecules would be achieved. Therefore, the design could provide a simple, accurate, universal platform for biological applications.

Tumor-Homing Cell-Penetrating Peptide Linked to Colloidal Mesoporous Silica Encapsulated (-)-Epigallocatechin-3-gallate as Drug Delivery System for Breast Cancer Therapy in Vivo.

Chemotherapy is the use of chemical drugs to prevent cancer cell proliferation, invasion, and metastasis, but a serious obstacle is that chemotherapeutics strikes not only on cancerous cells, but also on normal cells. Thus, anticancer drugs without side effects should be developed and extracted. (-)-Epigallocatechin-3-gallate (EGCG), a major ingredient of green tea, possesses excellent medicinal values, such as anticancer effects, DNA-protective effects, etc. However, EGCG will be mostly metabolized if it is directly orally ingested. Here, we report a drug delivery system (DDS) for loading EGCG to enhance its stability, promising target and anticancer effects in vitro and in vivo. The designed DDS is composed of three main moieties: anticancer drug, EGCG; drug vector, colloidal mesoporous silica (CMS); target ligand, breast tumor-homing cell-penetrating peptide (PEGA-pVEC peptide). Based on the results of CCK-8 assay, confocal imaging, cell cycle analysis, and Western blot, the anticancer effect of EGCG was increased by loading of EGCG into CMS and CMS@peptide. In vivo treatment displayed that CMS had a not obvious influence on breast tumor bearing mice, but CMS@peptide@EGCG showed the greatest tumor inhibition rate, with about 89.66%. H&E staining of organs showed no tissue injury in all experimental groups. All the above results prove that EGCG is an excellent anticancer drug without side effects and CMS@peptide could greatly promote the efficacy of EGCG on breast tumors by targeted accumulation and release, which provide much evidence for the CMS@peptide as a promising and targeting vector for DDS.

Bacteria-Affinity 3D Macroporous Graphene/MWCNTs/Fe3O4 Foams for High-Performance Microbial Fuel Cells

Promoting the performance of microbial fuel cells (MFCs) relies heavily on the structure design and composition tailoring of electrode materials. In this work, three-dimensional (3D) macroporous graphene foams incorporated with intercalated spacer of multiwalled carbon nanotubes (MWCNTs) and bacterial anchor of Fe3O4 nanospheres (named as G/MWCNTs/Fe3O4 foams) were first synthesized and used as anodes for Shewanella-inoculated microbial fuel cells (MFCs). Thanks to the macroporous structure of 3D graphene foams, the expanded electrode surface by MWCNTs spacing, as well as the high affinity of Fe3O4 nanospheres toward Shewanella oneidensis MR-1, the anode exhibited high bacterial loading capability. In addition to spacing graphene nanosheets for accommodating bacterial cells, MWCNTs paved a smoother way for electron transport in the electrode substrate of MFCs. Meanwhile, the embedded bioaffinity Fe3O4 nanospheres capable of preserving the bacterial metabolic activity provided guarantee for the long-term durability of the MFCs. With these merits, the constructed MFC possessed significantly higher power output and stronger stability than that with conventional graphite rod anode.

Synthesis of stabilizer-free gold nanoparticles by pulse sonoelectrochemical method.

In this paper, stabilizer-free gold nanoparticles (Au NPs) were synthesized by a facile pulse sonoelectrochemical method in the absence of stabilizer. The size and shape of the Au NPs can be controlled by adjusting current density, reaction time and the pH value of the precursor solution. The morphology and structure of the Au NPs were characterized by transmission electron microscopy (TEM), high resolution transmission electron microscopy (HRTEM), UV-visible spectra (UV-vis), energy-dispersive X-ray (EDX) and X-ray diffraction (XRD). The pH value has a great effect on the size and dispersion of the obtained Au NPs. The Au NPs could further used as substrate for fabrication of HRP biosensor which exhibited excellent biocatalytical activity with high sensitivity and rapid response. This method provides a facile route for the synthesis of stabilizer-free Au NPs. Since the preparation process do not need the addition of any surfactants/capping agent, the resulting Au NPs are suitable for the applications in fields of biology and catalysis.

Magnetite/Ceria-Codecorated Titanoniobate Nanosheet: A 2D Catalytic Nanoprobe for Efficient Enrichment and Programmed Dephosphorylation of Phosphopeptides

Global characterization and in-depth understanding of phosphoproteome based on mass spectrometry (MS) desperately needs a highly efficient affinity probe during sample preparation. In this work, a ternary nanocomposite of magnetite/ceria-codecorated titanoniobate nanosheet (MC-TiNbNS) was synthesized by the electrostatic assembly of Fe3O4 nanospheres and in situ growth of CeO 2 nanoparticles on pre-exfoliated titanoniobate and eventually utilized as the probe and catalyst for the enrichment and dephosphorylation of phosphopeptides. The two-dimensional (2D) structured titanoniobate nanosheet not only promoted the efficacy of capturing phosphopeptides with enlarged surface area, but also functioned as a substrate for embracing the magnetic anchor Fe3O4 to enable magnetic separation and mimic phosphatase CeO2 to produce identifying signatures of phosphopeptides. Compared to single-component TiNbNS or CeO2 nanoparticles, the ternary nanocomposite provided direct evidence of the number of phosphorylation sites while maintaining the enrichment efficiency. Moreover, by altering the on-sheet CeO2 coverage, the dephosphorylation activity could be fine-tuned, generating continuously adjustable signal intensities of both phosphopeptides and their dephosphorylated tags. Exhaustive detection of both mono- and multiphosphorylated peptides with precise counting of their phosphorylation sites was achieved in the primary mass spectra in the cases of digests of standard phosphoprotein and skim milk, as well as a more complex biological sample, human serum. With the resulting highly informative mass spectra, this multifunctional probe can be used as a promising tool for the fast and comprehensive characterization of phosphopeptides in MS-based phosphoproteomics.

A facile sonochemical route for the synthesis of MoS2/Pd composites for highly efficient oxygen reduction reaction.

For the alkaline fuel cell cathode reaction, it is very essential to develop novel catalysts with superior catalytic properties. Here, we report the synthesis of highly active and stable MoS2/Pd composites for the oxygen reduction reaction (ORR), via a simple, eco-friendly sonochemical method. The bulk MoS2 was first transformed into single and few layers MoS2 nanosheets through ultrasonic exfoliation. Then the exfoliated MoS2 nanosheets served as supporting materials for the nucleation and further in-situ growth of Pd nanoparticles to form MoS2/Pd composites via ultrasonic irradiation. Cyclic voltammetry and rotating disk voltammetry measurements demonstrate that as-prepared MoS2/Pd composites which provides a direct four-electron pathway for the ORR, have better electrocatalytic activity, long-term operation stability than commercial Pt/C catalyst. We expect that the present work would provide a promising strategy for the development of efficient oxygen reduction electrocatalyst. In addition, this study can also be extended to the preparation of other hybrid with desirable morphologies and functions.

Sonochemical preparation of stable porous MnO2 and its application as an efficient electrocatalyst for oxygen reduction reaction

Porous MnO2 as a non-noble metal oxygen reduction reaction (ORR) electrocatalyst was prepared by a simple sonochemical route. The as-prepared porous MnO2 exhibited higher electrocatalytic activity, superior stability and better methanol tolerance than commercial Pt/C catalyst in alkaline media. Furthermore, the ORR proceeded via a nearly four-electron pathway. Cyclic voltammetry (CV) and rotating-disk electrode (RDE) measurements verified that the ORR enhancement was attributed to the porous structure and good dispersity, which facilitated sufficient transport of ions, electrons, O2 and other reactants in the process of ORR. The results indicated that a facile and feasible sonochemical route could be used to prepare highly active porous MnO2 electrocatalyst for ORR, which might be promising for direct methanol fuel cells.