Jiasi Wang

Non-Enzymatic-Browning-Reaction: A Versatile Route for Production of Nitrogen-Doped Carbon Dots with Tunable Multicolor Luminescent Display

The non-enzymatic browning, namely Maillard reaction is commonly invoked to account for abiotic chemical transformations of organic matter. Here we report a new reaction pathway via the Maillard reaction to systematically synthesize a series of nitrogen-doped carbon dots (C-dots) with superhigh quantum yield (QY) and tunable multicolor luminescent displayment. The starting materials are glucose and the serial amino acid analogues which allow systemically controlling luminescent and physicochemical properties of C-dots at will. Unexpectedly, the as-prepared C-dots possess bright photoluminescence with QY up to 69.1% which is almost the highest ever reported, favorable biocompatibility, excellent aqueous and nonaqueous dispersibility, ultrahigh photostability, and readily functionalization. We have demonstrated that they are particularly suitable for multicolor luminescent display and long-term and real-time cellular imaging. Furthermore, the methodology is readily scalable to large yield, and can provide sufficient amount of C-dots for practical demands.

3D Graphene Oxide–Polymer Hydrogel: Near‐Infrared Light‐Triggered Active Scaffold for Reversible Cell Capture and On‐Demand Release

An active cell scaffold based on a graphene-polymer hydrogel has been successfully fabricated. The macroporous hydrogel can efficiently capture cells not only through the bioadhesive ligand RGD but also through on-demand release of cells with an NIR light stimulus. The latter process shows better dynamic control over cells than traditional passive-hydrogel-based cell depots.

Near-Infrared Upconversion Controls Photocaged Cell Adhesion

Dynamic control of cell-surface interactions with near-infrared (NIR) light is particularly attractive for regeneration medicine and cell-based therapy. Herein we successfully achieve NIR-controlled cell adhesion with upconversion nanoparticles (UCNPs) based programmable substrate. The UCNPs can harvest the biocompatible NIR light and convert it into local UV light, which results in cleavage of the photocaged linkers and on-demand release of adhesive cells. The strategy also enables the feasibility of deep-tissue photocontrol of cell adhesion on substrate. Our work may open a new avenue for design of UCNP-based cell scaffolds to dynamically manipulate cell-matrix and cell-cell interactions.

Detection of a Prognostic Indicator in Early‐Stage Cancer Using Functionalized Graphene‐Based Peptide Sensors

Using a porphyrin-functionalized graphenemodifi ed electrode, an electrochemical impedance peptide sensor for labelfree detection of cyclin A2 has been constructed. This electrochemical sensor can not only detect protein in cancer cells but also differentiate cancer cells from normal ones. Furthermore, the assay provides the potential of using a simple electrochemical technique to estimate the effi ciency of anticancer drugs in cancer therapy.

Label‐Free Ultrasensitive Detection of Human Telomerase Activity Using Porphyrin‐Functionalized Graphene and Electrochemiluminescence Technique

Using porphyrin-functionalized graphene, we construct a PCR-free, low-cost, rapid, and electrochemiluminenscence (ECL) assay for detection of telomerase activity that has been demonstrated in six different cell lines and can be used as initial screening of G-quadruplex DNA binding agents and telomerase inhibitors. This ECL sensor shows highly sensitive for detection of telomerase with the detection limit as low as 10 HeLa cells mL(-1) .

Visualizing Human Telomerase Activity with Primer‐Modified Au Nanoparticles

Telomerase is over-expressed in over 85% of all known human tumors. This renders the enzyme a valuable biomarker for cancer diagnosis and an important therapeutic target. The most widely used telomeric repeat amplification protocol (TRAP) assay has been questioned for telomerase detection. It is reported that human telomerase activity can be visualized by using primer-modified Au nanoparticles. The working principle is based on the elongated primers conjugated to the gold nanoparticle (AuNP) surface, which can fold into a G-quadruplex to protect the AuNPs from the aggregation. The developed simple and sensitive colorimetric assay can measure telomerase activity down to 1 HeLa cell µL(-1). More importantly, this assay can be easily extended to high-throughput and automatic format. The AuNP-TS method is PCR-free and therefore avoids the amplification-related errors and becomes more reliable to evaluate telomerase activity. This assay has also been used for initial screening of telomerase inhibitors as anticancer drug agents.

Insights into the biomedical effects of carboxylated single-wall carbon nanotubes on telomerase and telomeres

Both human telomeric G-rich and C-rich DNA have been considered as specific drug targets for cancer therapy. However, due to i-motif structure instability and lack of specific binding agents, it remains unclear whether stabilization of telomeric i-motif can inhibit telomerase activity. Single-walled carbon nanotubes (SWNTs) have been reported as the first ligand that can selectively stabilize human telomeric i-motif DNA. Here we report that SWNTs can inhibit telomerase activity through stabilization of i-motif structure. The persistence of i-motif and the concomitant G-quadruplex eventually leads to telomere uncapping and displaces telomere-binding proteins from telomere. The dysfunctional telomere triggers DNA damage response and elicits upregulation of p16 and p21 proteins. This is the first example that SWNTs can inhibit telomerase activity and interfere with the telomere functions in cancer cells. These results provide new insights into understanding the biomedical effects of SWNTs and the biological importance of i-motif DNA.

Near-Infrared- and pH-Responsive System for Reversible Cell Adhesion using Graphene/Gold Nanorods Functionalized with i-Motif DNA

Near-Infraredand pH-Responsive System for Reversible Cell Adhesion using Graphene/Gold Nanorods Functionalized with i-Motif DNA It’s a keeper! A dual near-infrared (NIR)and pH-responsive system for the controlled catch-and-release of cells was achieved using graphene/Au nanorods as a substrate and double-stranded DNA as a switchable linker for cell immobilization (see scheme). This substrate was shown to respond to cycles of NIR light and changes in pH, and released undamaged cells from the surface. Angewandte Chemie

pH-responsive NIR enhanced drug release from gold nanocages possesses high potency against cancer cells

We report a smart therapeutic nanoplatform based on Fe(3)O(4)@CaP capped gold nanocages, which integrates magnetic targeting, photothermal therapy and chemotherapy for killing cancer cells. Combining photothermal- and chemo-therapy results in a synergistic effect in cancer treatment.

Nanoceria-Triggered Synergetic Drug Release Based on CeO2-Capped Mesoporous Silica Host-Guest Interactions and Switchable Enzymatic Activity and Cellular Effects of CeO2

Herein, a pH stimuli-responsive vehicle for intracellular drug delivery using CeO2 capped mesoporous silica nanoparticles (MSN) is reported. β-Cyclodextrin-modified CeO2 nanoparticles could cap onto ferrocene-functionalized mesoporous silica through host-guest interactions. After internalization into A549 cells by a lysosomal pathway, the ferrocenyl moieties are oxidized to ferrocenium ions by CeO2 lids, which could trigger the uncapping of the CeO2 and cause the drugs release. Because of the pH-dependent toxicity, the CeO2 here behaves as a multi-purpose entity that not only acts as a lid but also exhibits a synergistic antitumor effect on cancer cells. Meanwhile, the cell protective effect of CeO2 nanoparticles alone is demonstrated, which ensures that the dissolved CeO2 nanoparticles can be non-toxic to normal cells.