Xinjian Yang

Near‐Infrared Light‐Triggered, Targeted Drug Delivery to Cancer Cells by Aptamer Gated Nanovehicles

A novel cell-targeting, near-infrared light-responsive drug delivery platform based on mesoporous silica-coated gold nanorods that are surface-functionalized with aptamer DNA is constructed. Aptamer DNA is used as both capping and targeting agent. In vitro studies show the feasibility of using this nanocarrier for targeted and noninvasive remote controlled drug delivery and photothermal therapy.

Using Graphene Oxide High Near-Infrared Absorbance for Photothermal Treatment of Alzheimer's Disease

A novel strategy to dissociate amyloid aggregation is presented, using localised heat generation from a clinically used amyloid staining dye, thioflavin-S (ThS)-modified graphene oxide (GO) under NIR laser irradiation. Compared to traditional chemotherapies, photothermal therapy shows reduced side effects and improved selectivity and safety.

Polyvalent Nucleic Acid/Mesoporous Silica Nanoparticle Conjugates: Dual Stimuli‐Responsive Vehicles for Intracellular Drug Delivery

The distinctive characteristics of mesoporous silica nanoparticles (MSPs) such as thermal stability, tunable pore sizes, large load capacity, and the ease of surface functionalization make these scaffolds ideal for the design of nanodevices and “on-command” delivery applications. To date, several MSPbased controlled-release systems have been synthesized by using different kinds of capping agents including organic molecules, nanoparticles, and supramolecular assemblies. “On-demand” release systems that respond to a range of stimuli, including redox, 4a,5] pH or temperature, enzymes, competitive binding, and photoirradiation 4b,9] have recently been reported. Despite these burgeoning achievements, many of the existing capping systems have disadvantages such as the use of stimuli that are complicated and/or difficult to apply, poor applicability in aqueous solutions and biocompatibility, and the toxicity of the capping agents used. In particular, regardless of recent reports on capped MSPs that can be uncapped by certain enzymes or carbohydrates, the utility of MSP-based devices involving biomolecules for real delivery systems is still in its infancy. Therefore, the search for effective systems that, in particular, respond to internal biological stimuli still remains a big challenge in this field. Herein we describe the design and construction of a stimuli-responsive vehicle for intracellular drug delivery using a polyvalent nucleic acid/MSP “click” conjugate that responds to both external and endogenous activation. Nucleic acids have been recognized as attractive building blocks for nanotechnology and materials science owing to the remarkable specificity and versatility of these units. The unique structural motif and self-recognition properties of duplex DNA, including temperature-dependent assembly, as well as the enzymatic recognition of specific encoded bases, may be applied as triggers for functional DNA manipulation. As shown in Figure 1, self-complementary duplex DNA was anchored to the openings of the MSPs and was utilized as a cap for trapping the guest molecules within the porous

The use of multifunctional magnetic mesoporous core/shell heteronanostructures in a biomolecule separation system

A multifunctional magnetic mesoporous core/shell heteronanostructure (designated as Fe(3)O(4)@NiSiO(3)) has been designed and constructed that combined the capacity of effective protein purification from protein mixture and selective low molecule weight (MW) biomolecule enrichment. The nanoparticle is composed by magnetite nanoparticle with immobilized metal ion surface and solid porous shell which presents a number of important features, such as controllable shell thickness, uniform pore size and excellent magnetism. By taking advantages of the high affinity of Ni(2+) on the shell surface toward His-tagged proteins and the fast response toward an assistant magnet, the heteronanoparticles can be applied to selectively bind to and magnetically separate of His-tagged proteins from a cell lysate of E. coli. Additionally, owing to the homogeneous 3D mesopores on the nickel silicate shell, the heteronanoparticles can selectively capture low MW biomolecules from complex mixture. Significantly, it is expected that this approach can be extended to other biomolecule separation and enrichment systems by changing the immobilized surface and the pore size.

Hybrid Mesoporous Silica-Based Drug Carrier Nanostructures with Improved Degradability by Hydroxyapatite

Potential bioaccumulation is one of the biggest limitations for silica nanodrug delivery systems in cancer therapy. In this study, a mesoporous silica nanoparticles/hydroxyapatite (MSNs/HAP) hybrid drug carrier, which enhanced the biodegradability of silica, was developed by a one-step method. The morphology and structure of the nanoparticles were characterized by TEM, DLS, FT-IR, XRD, N2 adsorption-desorption isotherms, and XPS, and the drug loading and release behaviors were tested. TEM and ICP-OES results indicate that the degradability of the nanoparticles has been significantly improved by Ca(2+) escape from the skeleton in an acid environment. The MSNs/HAP sample exhibits a higher drug loading content of about 5 times that of MSNs. The biological experiment results show that the MSNs/HAP not only exhibits good biocompatibility and antitumor effect but also greatly reduces the side effects of free DOX. The as-synthesized hybrid nanoparticles may act as a promising drug delivery system due to their good biocompatibility, high drug loading efficiency, pH sensitivity, and excellent biodegradability.

Exonuclease-aided amplification for label-free and fluorescence turn-on DNA detection based on aggregation-induced quenching

A facile, universal and label-free fluorescence turn-on amplification strategy for the detection of DNA has been reported, which can achieve ultralow femtomolar detection of a target gene sequence with high selectivity.

Aptamer-Capped Multifunctional Mesoporous Strontium Hydroxyapatite Nanovehicle for Cancer-Cell-Responsive Drug Delivery and Imaging

A novel cancer-cells-triggered controlled-release gadolinium-doped luminescent and mesoporous strontium hydroxyapatite nanorods (designated as Gd:SrHap nanorods) system using cell-type-specific aptamers as caps has been constructed. Aptamers behave as a dual-functional molecule that acts as not only a lid but also a targeted molecular that can be used in an effective way for therapeutically special cancer cells. After incubated with cancer cells, for example, MCF-7 cells, the doxorubicin-loaded and aptamer-capped Gd:SrHap nanorods (designated as Gd:SrHap-Dox-aptamer) can be internalized into MCF-7 cells, resulting in the pore opening and drug releasing. Furthermore, the high biocompatibility and biodegradability Gd:SrHap nanorods with blue autofluorescence and paramagnetism could serve as a good contrast agent of targeting fluorescence and magnetic resonance imaging. We envision that this Gd:SrHap system could play a significant role in developing new generations of site-selective, controlled-release delivery and interactive sensory nanodevices.

Photosensitizer-incorporated G-quadruplex DNA-functionalized magnetofluorescent nanoparticles for targeted magnetic resonance/fluorescence multimodal imaging and subsequent photodynamic therapy of cancer

A smart heteronanostructure has been constructed for targeted photodynamic therapy and magnetic fluorescent imaging of cancer cells using photosensitizer-incorporated G-quadruplex DNA functionalized magnetic nanoparticles.

Reduced Graphene Oxide Functionalized with a Luminescent Rare-Earth Complex for the Tracking and Photothermal Killing of Drug-Resistant Bacteria

An antibacterial platform based on multifunctional reduced graphene oxide (rGO) that is responsive to near-infrared (NIR) light has been constructed. By introducing a luminescent Eu(3+) complex and vancomycin for bacteria tracking into one system, this platform could specifically recognize and light up bacteria. Antibacterial activity of this nanoscale construction under NIR illumination was investigated. Upon illumination with NIR light, this nanoscale architecture generates great heat locally, resulting in the death of drug-resistant bacteria. These results indicate that the ability of this nanoscale platform to kill drug-resistant bacteria has great potential for clinical pathogenic bacteria diagnosis and treatment.

Enzymatic Manipulation of DNA‐Modified Gold Nanoparticles for Screening G‐Quadruplex Ligands and Evaluating Selectivities

Enzymatic manipulation of DNA on well-dispersed gold nanoparticles (AuNPs) offers an ideal system for high-throughput screening of G-quadruplex ligands and evaluation of their selectivity with respect to duplex and quadruplex DNA (see figure). This work has implications for the future use of nanoparticle-based technologies in the discovery of potential cancer therapeutic agents.