Kewei Wang

Hydrophobic IR-780 Dye Encapsulated in cRGD-Conjugated Solid Lipid Nanoparticles for NIR Imaging-Guided Photothermal Therapy

This is high demand to enhance the accumulation of near-infrared theranostic agents in the tumor region, which is favorable to the effective phototherapy. Compared with indocyanine green (a clinically applied dye), IR-780 iodide possesses higher and more stable fluorescence intensity and can be utilized as an imaging-guided PTT agent with laser irradiation. However, lipophilicity and short circulation time limit its applications in cancer imaging and therapy. Moreover, solid lipid nanoparticles (SLNs) conjugated with c(RGDyK) was designed as efficient carriers to improve the targeted delivery of IR-780 to the tumors. The multifunctional cRGD-IR-780 SLNs exhibited a desirable monodispersity, preferable stability and significant targeting to cell lines overexpressing αvβ3 integrin. Additionally, the in vitro assays such as cell viability and in vivo PTT treatment denoted that U87MG cells or U87MG transplantation tumors could be eradicated by applying cRGD-IR-780 SLNs under laser irradiation. Therefore, the resultant cRGD-IR-780 SLNs may serve as a promising NIR imaging-guided targeting PTT agent for cancer therapy.

Label-free detection of Pb2+ based on aggregation-induced emission enhancement of Au-nanoclusters

Interestingly, the glutathione capped Au-nanoclusters presented here showed a unique optical performance compared with their homological AuNPs with larger size. The luminescence intensity of the AuNCs could be enhanced due to the formation of aggregates. The AuNCs were then employed as a visual probe for the detection of Pb2+ based on the aggregation-induced emission enhancement (AIEE) property of the AuNCs. When the luminous glutathione capped AuNCs probes encountered Pb2+ ions, they rapidly formed aggregates through GSH–Pb2+ interaction in 1 minute, resulting in an enhanced luminescence intensity. The enhanced luminescence intensities showed a linear dependence on the concentrations of Pb2+ with satisfactory selectivity towards 12 kinds of divalent metal ions. More importantly, the probe can also be used for on-site testing to inspect Pb2+ contamination by using a portable UV flashlight.

A Multiscale TiO2 Nanorod Array for Ultrasensitive Capture of Circulating Tumor Cells

In this work, a uniform multiscale TiO2 nanorod array is fabricated to provide a multi-scale interacting platform for cell capture, which exhibits excellent capture specificity and sensitivity of the target cells after modification with bovine serum albumin (BSA) and DNA aptamer. After studying the capture performance of the BSA-aptamer TiO2 nanorod substrates and other nanostructured substrates, we can conclude that the multisacle TiO2 nanorod substrates could indeed effectively enhance the capture yields of target cancer cells. The capture yield of artificial blood samples on the BSA-aptamer TiO2 nanorod substrates is up to 85%-95%, revealing the potential application of the TiO2 nanorods on efficient and sensitive capture of rare circulating tumor cells.

A hemin binding G-quadruplex/Pb2+ complex to construct a visible light activated photoelectrochemical sensor on a ZnO/BiOI heterostructure

This study reported the development of a p–n heterojunction photoelectrochemical biosensor using a G-quadruplex as the recognition system. The n-type ZnO nanorods and p-type BiOI nanoflakes were combined to form the heterostructure by in situ growth of BiOI attributed to a simple impregnating-hydroxylation method. This simple p–n heterojunction fabrication method could facilitate the development of rapid and sensitive visible light activated PEC sensors. In this study, the ZnO/BiOI photoelectrode showed a rapid photocurrent decrease in the presence of Pb2+ due to the electron withdrawing effect of hemin which bound with the G-quadruplex/Pb2+ complex. This PEC biosensor exhibited a good response following the concentration of Pb2+ in the range from 10 to 100 μM.

Multifunctional Nanofibers for Specific Purification and Release of CTCs

Recovering pure and viable circulating tumor cells (CTCs) from blood has been a challenging task for molecular characterization and functional analysis, which has attracted wide attention these days. Herein, we fabricate a thermoresponsive chitosan nanofiber substrate to effectively capture, purify, and release the target cancer cells, assisted by PNIPAAm brushes and DNA hybridization. The PNIPAAm brushes are designed to enable WBCs to detach from aptamer-PNIPAAm-chitosan-nanofiber (aptamer-P-CNFs) surfaces during the conformational transition. Meanwhile these specific captured CTCs are retained at a high purity. Moreover, effective and intact release of CTCs from the substrates without any foreign agents is realized by complementary sequences efficiently hybridizing with aptamers, and the specific cell release makes CTCs further purified. The present work provides a new strategy in the design of biointerface for recovering target CTCs from whole blood samples with high purity.

A photoelectrochemical sensor through quenching of photoinduced electrons based on a G-quadruplex/hemin complex

The decreasing photocurrent from photoinduced electron transfer by the formation of a G-quadruplex/hemin complex in the presence of K+ was utilized as a sensing signal for developing a novel label-free photoelectrochemical detection method.

Quinaldine red as a fluorescent light-up probe for i-motif structures

Quinaldine red as a new fluorescent probe for i-motif structures was reported for the first time. When binding to i-motifs, quinaldine red exhibits a remarkable increase in its fluorescence, which benefits i-motif-involved label-free systems.

Multi-arm star-branched polymer as an efficient contrast agent for tumor-targeted magnetic resonance imaging

Contrast agents with high efficiency and safety are excellent candidates as magnetic resonance imaging probes. Herein, a multi-arm star-branched polymer was prepared by conjugating oligolysine onto a rigid hyperbranched poly(amido amine) core via click chemistry, followed by covalent modification with Gd chelate and folic acid (FA-OLL-g-HBPAMAM-DTPA-Gd). This multi-arm star-branched polymer contrast agent exhibited much higher longitudinal relaxivity (r1 = 13.34 mM-1 s-1) as compared to a commercial contrast agent (Gd-DTPA, r1 = 4.2 mM-1 s-1). No obvious histological toxicity was observed from histological assessment, which illustrated that FA-OLL-g-HBPAMAM-DTPA-Gd exhibited excellent biocompatibility. Both in vitro and in vivo MRI studies showed that the macromolecular contrast agent provided better signal contrast enhancement and presented obvious target specificity to KB xenografts with a sufficient time window for MRI scanning; moreover, this multi-arm star-branched mCA has great potential for developing sensitive and biocompatible MRI CA with targeting ability.

A novel photoelectrochemical aptasensor based on the modulation of a dye sensitized TiO2 photoelectrode

An N719 dye labeled short DNA chain is introduced onto the surface of a TiO2 photoelectrode by hybridizing with a pre-immobilized thrombin aptamer to enhance the photocurrent response. After incubating with thrombin, both the dye labeled chain releasing from the photoelectrode and the bound thrombin blocking the electron transfer resulted in a decreased photocurrent.