Water-Based Black Phosphorus Hybrid Nanosheets as a Moldable Platform for Wound Healing Applications.

Black phosphorus (BP) nanosheets with unique biocompatibility and superior optical performance have attracted enormous attention in material science. However, their instability and poor solution-processability severely limit their clinical applications. In this work, we demonstrate the use of silk fibroin (SF) as an exfoliating agent to produce thin-layer BP nanosheets with long-term stability and facile solution-processability. Presence of SF prevents rapid oxidation and degradation of the resultant BP nanosheets, enhancing their performance in physiological environment. The SF-modified BP nanosheets exhibit subtle solution-processability and are fabricated into various BP-based material formats. As superior photothermal agents, BP-based wound dressings effectively prevent bacterial infection and promote wound repair. Therefore, this work opens new avenues for unlocking current challenges of BP nanosheet applications for practical biomedical purposes.

A black phosphorus nanosheet-based siRNA delivery system for synergistic photothermal and gene therapy.

Gene therapy with small interfering RNA (siRNA) has been proved to be a promising technology to treat various diseases by hampering the production of target proteins. However, developing a delivery system that has high efficiency in transporting siRNA without obvious side effects remains a challenge. Herein, we designed a new survivin siRNA delivery system based on polyethyleneimine functionalized black phosphorus (BP) nanosheets which could suppress tumor growth by silencing survivin expression. Combined with the photothermal properties of the BP nanosheets, the presented delivery system shows excellent therapy efficiency for tumors. Therefore, the BP-based delivery system would be a promising tool for future clinical applications.

Black Phosphorus Quantum Dots with Renal Clearance Property for Efficient Photodynamic Therapy.

Black phosphorus (BP) nanomaterials have emerged as rapidly rising stars in the field of nanomedicine. In this work, BP quantum dots (BPQDs) are synthesized and their potential as photosensitizers is investigated for the first time. The BPQDs present good stability in physiological medium and no appreciable cytotoxicity. More importantly, the BPQDs can be rapidly eliminated from the body in their intact form via renal clearance due to their ultrasmall hydrodynamic diameter (5.4 nm). Both in vitro and in vivo studies indicate that the BPQDs have excellent photodynamic effect under light irradiation that can effectively generate reactive oxygen species to kill cancer cells. The BPQDs thus can serve as biocompatible and powerful photosensitizers for efficient photodynamic therapy.

Silk fibroin-assisted exfoliation and functionalization of transition metal dichalcogenide nanosheets for antibacterial wound dressings.

Two-dimensional transition metal dichalcogenides (TMDs) have attracted rapidly increasing attention due to their fascinating properties and potential applications. However, scalable and cost-effective methods to produce thin-layer TMD nanosheets and their functional composites with environmental benignity are still limited. Herein, we develop a facile and environmentally friendly method for the scalable production of thin-layer TMD nanosheets in an aqueous medium by using silk fibroin, a natural and abundant biopolymer, as the exfoliating agent. Specifically, carboxyl-modified silk fibroin significantly improves the exfoliation efficiency, achieving the high-yield production of thin-layer MoSe2 nanosheets with good solution stabilization and excellent biocompatibility. Strong binding interactions endow the resultant MoSe2 nanosheets with unprecedentedly high concentrations. By virtue of the solution-processability of silk fibroin, MoSe2 hybrid nanosheets are readily fabricated into macroscopic freestanding films. Furthermore, due to the superior peroxidase-like activity of MoSe2 nanosheets, MoSe2-based films show rapid and effective wound disinfection and healing efficacy with the use of low-dose H2O2in vivo, avoiding the side effects of high-dose H2O2 in traditional medical therapy. This work may offer new opportunities to apply two-dimensional TMD nanosheets for clinical applications.

Polyphenol-Inspired Facile Construction of Smart Assemblies for ATP- and pH-Responsive Tumor MR/Optical Imaging and Photothermal Therapy.

Smart assemblies have attracted increased interest in various areas, especially in developing novel stimuli-responsive theranostics. Herein, commercially available, natural tannic acid (TA) and iron oxide nanoparticles (Fe3 O4 NPs) are utilized as models to construct smart magnetic assemblies based on polyphenol-inspired NPs-phenolic self-assembly between NPs and TA. Interestingly, the magnetic assemblies can be specially disassembled by adenosine triphosphate, which shows a stronger affinity to Fe3 O4 NPs than that of TA and partly replaces the surface coordinated TA. The disassembly can further be facilitated by the acidic environment hence causing the remarkable change of the transverse relaxivity and potent "turn-on" of fluorescence (FL) signals. Therefore, the assemblies for specific and sensitive tumor magnetic resonance and FL dual-modal imaging and photothermal therapy after intravenous injection of the assemblies are successfully employed. This work not only provides understandings on the self-assembly between NPs and polyphenols, but also will open new insights for facilely constructing versatile assemblies and extending their biomedical applications.

Highly Selective and Sensitive Electrochemiluminescence Biosensor for p53 DNA Sequence Based on Nicking Endonuclease Assisted Target Recycling and Hyperbranched Rolling Circle Amplification.

An ultrasensitive and specific electrochemiluminescence (ECL) biosensor has been designed for the p53 DNA sequence, which is based on cascade signal amplification of nicking endonuclease assisted target recycling and hyperbranched rolling circle amplification (HRCA). First of all, biotin modified hairpin capture DNA (HP) probe was immobilized on the surface of streptavidin magnespheres paramagnetic particles (PMPs). Target DNA hybridized with the loop portion of the HP probe, therefore unfolding HP to form a double-stranded DNA (dsDNA) containing the specific nicking site of the nicking endonuclease. Then, the nicking endonuclease recognized the specific nicking site and cleaved the HP into two pieces, liberating target DNA and the complementary sequence piece for the padlock probe. The intact target DNA would initiate the next cycle of hybridization and cleavage, thereby releasing multiple complementary sequences for the padlock probes. The liberated complementary sequences hybridized with the padlock probes, subsequently inducing the HRCA reaction and generating numerous dsDNA segments. Herein, Ru(phen)3(2+) was embedded into dsDNA and worked as ECL signal reporter. The reaction products were eventually pretreated by dialysis tube with the cutoff membrane to remove the residual Ru(phen)3(2+) in the solution for the following ECL measurements. Using this cascade amplification strategy, an ultrasensitive p53 DNA sequence detection method was developed with a wide linear range from 0.05 to 100 fM and a low detection limit of 0.02 fM. Moreover, this cascade amplified ECL biosensor had specific recognition capacity for noncomplementary and single- and double-base mismatched DNA. The proposed ECL biosensor might have a great potential in biomedical research and clinic analysis.

Plant Polyphenol-Assisted Green Synthesis of Hollow CoPt Alloy Nanoparticles for Dual-Modality Imaging Guided Photothermal Therapy.

Theranostic nanomedicines that integrate diagnostic and therapeutic moieties into a single nanoscale platform are playing an increasingly important role in fighting cancer. Here, a facile and green synthetic strategy for hollow CoPt alloy nanoparticles (HCPA-NPs) using plant polyphenols as assisted agents is reported for the first time. This novel strategy enables size-controlled synthesis of HCPA-NPs through the control of the molecular sizes of polyphenols. It is also a versatile strategy for synthesizing other hollow alloy nanoparticles with various metal compositions due to the diverse metal-chelating ability of the polyphenols. Further studies show that HCPA-NPs have good biocompatibility and can be successfully implemented for magnetic resonance and photoacoustic dual-modal imaging guided photothermal therapy. This work brings new insights for the green synthesis of hollow nanoparticles and extends these biocompatible nanoparticles for theranostic applications.

Dual-enhanced photothermal conversion properties of reduced graphene oxide-coated gold superparticles for light-triggered acoustic and thermal theranostics.

A rational design of highly efficient photothermal agents that possess excellent light-to-heat conversion properties is a fascinating topic in nanotheranostics. Herein, we present a facile route to fabricate size-tunable reduced graphene oxide (rGO)-coated gold superparticles (rGO-GSPs) and demonstrate their dual-enhanced photothermal conversion properties for photoacoustic imaging and photothermal therapy. For the first time, graphene oxide (GO) was directly used as an emulsifying agent for the preparation of gold superparticles (GSPs) with near-infrared absorption by the emulsion method. Moreover, GO spontaneously deposited on the surface of GSPs could also act as the precursor of the rGO shell. Importantly, both the plasmonic coupling of the self-assembled gold nanoparticles and the interaction between GSPs and rGO endow rGO-GSPs with enhanced photothermal conversion properties, allowing rGO-GSPs to be used for sensitive photoacoustic detection and efficient photothermal ablation of tumours in vivo. This study provides a facile approach to prepare colloidal superparticles-graphene hybrid nanostructures and will pave the way toward the design and optimization of photothermal nanomaterials with improved properties for theranostic applications.

Co9 Se8 nanoplates as a new theranostic platform for photoacoustic/magnetic resonance dual-modal-imaging-guided chemo-photothermal combination therapy.

A new theranostic platform is developed based on biocompatible poly(acrylic acid) (PAA)-Co9 Se8 nanoplates. These PAA-Co9 Se8 nanoplates are successfully utilized for photoacoustic imaging (PAI)/magnetic resonance imaging (MRI) dual-modal imaging. Moreover, the PAA-Co9 Se8 -DOX shows pH-responsive chemotherapy and enables the combination of photothermal therapy and chemotherapy to receive superior antitumor efficacy. This work promises further exploration of 2D nanoplatforms for theranostic applications.

Polypyrrole nanoprobes with low non-specific protein adsorption for intracellular mRNA detection and photothermal therapy.

In this work, we discovered that polypyrrole nanoparticles (PPy NPs) displayed a low non-specific protein adsorption. We herein present the first PPy NP-based biosensing platform for intracellular mRNA detection in living cells. We also demonstrate that PPy NPs exhibit high NIR absorbance and can be utilized for cancer photothermal therapy.

Topological insulator bismuth selenide as a theranostic platform for simultaneous cancer imaging and therapy.

Employing theranostic nanoparticles, which combine both therapeutic and diagnostic capabilities in one dose, has promise to propel the biomedical field toward personalized medicine. Here we investigate the theranostic properties of topological insulator bismuth selenide (Bi2Se3) in in vivo and in vitro system for the first time. We show that Bi2Se3 nanoplates can absorb near-infrared (NIR) laser light and effectively convert laser energy into heat. Such photothermal conversion property may be due to the unique physical properties of topological insulators. Furthermore, localized and irreversible photothermal ablation of tumors in the mouse model is successfully achieved by using Bi2Se3 nanoplates and NIR laser irradiation. In addition, we also demonstrate that Bi2Se3 nanoplates exhibit strong X-ray attenuation and can be utilized for enhanced X-ray computed tomography imaging of tumor tissue in vivo. This study highlights Bi2Se3 nanoplates could serve as a promising platform for cancer diagnosis and therapy.

Study on the electrochemical catalytic properties of the topological insulator Bi2Se3.

In this work, the electrochemical catalytic properties of the topological insulator bismuth selenide (Bi2Se3) were first studied. In the presence of Bi2Se3 the reduction current of dissolved O2 could be significantly enhanced. The electron transfer resistivity (Rct) was greatly reduced at the Bi2Se3-PVP modified electrode as evidenced by the electrochemical impedance spectrometry, implying that the topological insulator Bi2Se3 could facilitate the electron transfer at the interface due to the excellent surface conductivity. Based on the high electrochemical catalytic activity for the reduction of dissolved O2, the Bi2Se3-PVP modified electrode was used to detect glucose with the modification of glucose oxidase, and applied for the detection of glucose in human blood serum.

Simple colorimetric bacterial detection and high-throughput drug screening based on a graphene-enzyme complex.

A simple, colorimetric, sensitive, cost-effective and high-throughput system based on a positively charged graphene oxide-enzyme complex was developed for bacterial detection and drug screening.

A novel sensitive detection platform for antitumor herbal drug aloe-emodin based on the graphene modified electrode.

This paper has presented a novel strategy to carry out direct and sensitive determination of antitumor herbal drug aloe-emodin in complex matrices based on the graphene-Nafion modified glassy carbon (GN/GC) electrode. This proposed modified electrode showed good electrochemical response towards aloe-emodin (AE). Compared with the multiwall carbon nanotubes (MWCNTs) modified electrode, the GN/GC electrode has the advantages of higher sensitivity and lower cost. Under the optimized conditions, the calibration curve for AE concentration was linear in the range from 5 nmol/L to 1 µmol/L with the detection limit of 2 nmol/L. In addition, the practical analytical performance of the GN/GC electrode was examined by evaluating the selective detection of AE in natural aloe extracts and human urine samples with satisfied recovery. Therefore, the GN/GC electrode may hold great promise for fast, simple and sensitive detection and biomedical analysis of AE in complex matrices.

[Content of gentiopicroside and loganic acid in Radix gentianae and their fingerprints].

To develop a HPLC-DAD-ESI-TOF/MS analysis method for the determination of gentiopicroside and loganic acid in Radix gentianae samples and for the research of their fingerprints. The samples were extracted using ASE for 10 min under 100 degrees C and 9.65 MPa, and divided into water phase and chloroform phase and analyzed them with HPLC-DAD-ESI-TOF/MS method respectively. Based on this method, the HPLC fingerprints of Radix gentianae were established. Comparing the spectrogram and mass spectrum of the chromatogram peak with the reference value, three compounds in water phase were identified as gentiopicroside, asafetida acid and loganic acid. There is no report of the compounds in chloroform phase. The content of gentiopicroside and loganic acid in samples of different groups were determined, separately. The fingerprints were compared by the software of the similarity evaluation system for chromatographic fingerprint. The water phase fingerprint congruence coefficients of samples from six different areas were above 0.90, however, the chloroform phase fingerprint congruence coefficients were within 0.62 -0.99. This method can be used for determination of potent component in Radix gentianae and its quality control. Radix gentianae from different producing areas have the largest diversities, and the diversities embodied in the content of chloroform phase compounds.

Surface molecularly imprinted nanowires for biorecognition.

Herein we present a novel method for preparation of surface molecularly imprinted size-monodisperse nanowires. The imprint molecule is immobilized on the pore walls of a silane-treated nanoporous alumina membrane. The nanopores are then filled with the monomer mixture, and the polymerization is initiated. The alumina membrane is subsequently removed by chemical dissolution, leaving behind polypyrrole nanowires with glutamic acid binding sites situated at the surface. These nanowires can be dissolved in aqueous media, and their applications therefore should be compatible with procedures in which biological antibodies might otherwise be used. For example, the analyte molecule can be tagged with various markers, such as fluorescence probes and enzymes, whereby the problem of steric hindrance is avoided. Furthermore, these surface-imprinted nanowires are likely suited for imprinting and recognition of large-molecular-weight peptides and proteins. Related work is currently being undertaken in our laboratory.