Xiaowei Xu

Bio: Xiaowei Xu is an academic researcher from Jilin University. The author has contributed to research in topics: Bone regeneration & Materials science. The author has an hindex of 11, co-authored 22 publications receiving 668 citations.

pH- and Temperature-Sensitive Hydrogel Nanoparticles with Dual Photoluminescence for Bioprobes

Abstract: This study demonstrates high contrast and sensitivity by designing a dual-emissive hydrogel particle system, whose two emissions respond to pH and temperature strongly and independently. It describes the photoluminescence (PL) response of poly(N-isopropylacrylamide) (PNIPAM)-based core/shell hydrogel nanoparticles with dual emission, which is obtained by emulsion polymerization with potassium persulfate, consisting of the thermo- and pH-responsive copolymers of PNIPAM and poly(acrylic acid) (PAA). A red-emission rare-earth complex and a blue-emission quaternary ammonium tetraphenylethylene derivative (d-TPE) with similar excitation wavelengths are inserted into the core and shell of the hydrogel nanoparticles, respectively. The PL intensities of the nanoparticles exhibit a linear temperature response in the range from 10 to 80 °C with a change as large as a factor of 5. In addition, the blue emission from the shell exhibits a linear pH response between pH 6.5 and 7.6 with a resolution of 0.1 unit, while t...

Aspirin-Based Carbon Dots, a Good Biocompatibility of Material Applied for Bioimaging and Anti-Inflammation

Abstract: The emerging photoluminescent carbon-based nanomaterials are promising in various fields besides cell imaging and carrier transport. Carbon nanomaterials with specific biological functions, however, are rarely investigated. Aspirin is a very common anti-inflammatory medication to relieve aches and pains. In this study, we have tried to create a carbon nanoparticle with aspirin, and we expect that this new carbon nanoparticle will have both anti-inflammatory and fluorescent biomarker functions. Fluorescent aspirin-based carbon dots (FACDs) were synthesized by condensing aspirin and hydrazine through a one-step microwave-assisted method. Imaging data demonstrated that FACDs efficiently entered into human cervical carcinoma and mouse monocyte macrophage cells in vitro with low cell toxicity. Results from quantitative polymerase chain reaction and histological analysis indicated that FACDs possessed effective anti-inflammatory effects in vitro and in vivo compared to aspirin only. Hematology, serum biochemist...

Composite Photothermal Platform of Polypyrrole-Enveloped Fe3O4 Nanoparticle Self-Assembled Superstructures

Abstract: Photothermal nanoplatforms with small size, low cost, multifunctionality, good biocompatibility and in particular biodegradability are greatly desired in the exploration of novel diagnostic and therapeutic methodologies. Despite Fe3O4 nanoparticles (NPs) have been approved as safe clinical agents, the low molar extinction coefficient and subsequent poor photothermal performance shed the doubt as effective photothermal materials. In this paper, we demonstrate the fabrication of polypyrrole (PPy)-enveloped Fe3O4 NP superstructures with a spherical morphology, which leads to a 300-fold increase in the molar extinction coefficient. The basic idea is the optimization of Fe3O4 electronic structures. By controlling the self-assembly of Fe3O4 NPs, the diameters of the superstructures are tuned from 32 to 64 nm. This significantly enhances the indirect transition and magnetic coupling of Fe ions, thus increasing the molar extinction coefficient of Fe3O4 NPs from 3.65 × 106 to 1.31 × 108 M–1 cm–1 at 808 nm. The env...

A Galvanic Replacement Route to Prepare Strongly Fluorescent and Highly Stable Gold Nanodots for Cellular Imaging

Abstract: Fluorescent gold nanodots (GNDs) are an important kind of nanoprobes. Herein, the application of galvanic replacement for the preparation of fluorescent GNDs is reported. Using presynthesized and size-controlled Ag nanodots (Ag NDs) as templates, the as-prepared GNDs have strong fluorescence (quantum yields ~10%) with high stability and surface bioactivity. The resultant GNDs show excellent photoluminescence properties with high photo-, time-, metal-, and pH-stability, which are attributed to the protective surface layer of glutathione (GSH) and the presence of Au(I)-S complexes on the surface of the gold core. GSH, a naturally occurring and readily available tripeptide with carboxyl and amino functional groups, allows good dispersion of the as-prepared GNDs in aqueous solution and favorable biocompatibility. These advantages, combined with their small size, mean that the as-prepared GNDs have potential application in biological labeling, especially as a DNA probe for the specific detection of nucleic acids. In this study, the CAL-27 cells are used as a model to evaluate the fluorescence imaging of GNDs.

Engineering Ordered and Nonordered Porous Noble Metal Nanostructures: Synthesis, Assembly, and Their Applications in Electrochemistry

Abstract: Nanostructures: Synthesis, Assembly, and Their Applications in Electrochemistry Chengzhou Zhu,† Dan Du,†,⊥ Alexander Eychmüller,‡ and Yuehe Lin*,†,§ †School of Mechanical and Materials Engineering, Washington State University, Pullman, Washington 99164-2920, United States Key Laboratory of Pesticide and Chemical Biology of the Ministry of Education, College of Chemistry, Central China Normal University, Wuhan 430079, P. R. China ‡Physical Chemistry, TU Dresden, Bergstrasse 66b, 01062 Dresden, Germany Pacific Northwest National Laboratory, Richland, Washington 99352, United States

Fluorescent Sensors Based on Aggregation-Induced Emission: Recent Advances and Perspectives

Abstract: Fluorescent sensors with advantages of excellent sensitivity, rapid response, and easy operation are emerging as powerful tools in environmental monitoring, biological research, and disease diagnosis. However, conventional fluorophores featured with π-planar structures usually suffer from serious self-quenching in the aggregated state, poor photostability, and small Stokes’ shift. In contrast to conventional aggregation-caused quenching (ACQ) fluorophores, the newly emerged aggregation-induced emission fluorogens (AIEgens) are featured with high emission efficiency in the aggregated state, which provide unique opportunities for various sensing applications with advantages of high signal-to-noise ratio, strong photostability, and large Stokes’ shift. In this review, we will first briefly give an introduction of the AIE concept and the turn-on sensing principles. Then, we will discuss the recent examples of AIE sensors according to types of analytes. Finally, we will give a perspective on the future develop...

Recent advances in the development of organic photothermal nano-agents

Abstract: Recently, photothermal therapy (PTT) has attracted tremendous attention because of its high efficacy in tumor ablation and minimal damage to normal tissues. While many inorganic nanomaterials, especially various gold nanostructures and nanocarbons, have been extensively explored for near-infrared (NIR) light triggered PTT in the past decade, a variety of organic photothermal agents have also emerged in recent years, aiming at replacing their inorganic counterparts which usually are not biodegradable. In this mini-review, we will summarize several typical classes of recently developed NIR-absorbing organic PTT nanoagents, which include NIR dye-containing micelles, porphysomes, protein-based agents, conjugated polymers, and organic/inorganic nanocomposites. The development of imaging-guided PTT and combination therapy will be introduced as well. Finally, the perspectives and challenges in the future development of PTT will be discussed.

Near-Infrared-Light-Activatable Nanomaterial-Mediated Phototheranostic Nanomedicines: An Emerging Paradigm for Cancer Treatment.

Abstract: Cancer is one of the most deadly diseases threatening the lives of humans. Although many treatment methods have been developed to tackle cancer, each modality of cancer treatment has its own limitations and drawbacks. The development of minimally invasive treatment modalities for cancers remains a great challenge. Near-infrared (NIR) light-activated nanomaterial-mediated phototherapies, including photothermal and photodynamic therapies, provide an alternative means for spatially and temporally controlled minimally invasive treatments of cancers. Nanomaterials can serve as nanocargoes for the delivery of chemo-drugs, diagnostic contrast reagents, and organic photosensitizers, and can be used to directly generate heat or reactive oxygen species for the treatment of tumors without the need for organic photosensitizers with NIR-light irradiation. Here, current progress in NIR-light-activated nanomaterial-mediated photothermal therapy and photodynamic therapy is summarized. Furthermore, the effects of size, shape, and surface functionalities of nanomaterials on intracellular uptake, macrophage clearance, biodistribution, cytotoxicities, and biomedical efficacies are discussed. The use of various types of nanomaterials, such as gold nanoparticles, carbon nanotubes, graphene, and many other inorganic nanostructures, in combination with diagnostic and therapeutic modalities for solid tumors, is briefly reviewed.