Yuzhi Chen

Bio: Yuzhi Chen is an academic researcher from Beijing University of Chemical Technology. The author has contributed to research in topics: Photothermal therapy & Singlet oxygen. The author has an hindex of 9, co-authored 14 publications receiving 295 citations. Previous affiliations of Yuzhi Chen include Academy of Military Medical Sciences.

Mitochondria-Targeted Polydopamine Nanocomposite with AIE Photosensitizer for Image-Guided Photodynamic and Photothermal Tumor Ablation

Abstract: Photodynamic therapy (PDT) and photothermal therapy (PTT) are two kinds of treatment for tumors. Herein, a new aggregation-induced emission (AIE)gen (MeO-TPE-indo, MTi) is synthesized with a D-π-A conjugated structure. MTi, which has an electron donor and an acceptor on a tetraphenylethene (TPE) conjugated skeleton, can induce the effective generation of reactive oxygen species (ROS) for PDT. With the guide of the indolium group, MTi can target and image mitochondrion selectively. In order to get good dispersion in water and long-time retention in tumors, MTi is modified on the surface of polydopamine nanoparticles (PDA NPs) to form the nanocomposite (PDA-MeO-TPE-indo, PMTi) by π-π and hydrogen interactions. PMTi is a nanoscale composite for imaging-guided PDT and PTT in tumor treatment, which is constructed with AIEgens and PDA for the first time. The organic functional molecules are combined with nanomaterials for building a multifunctional diagnosis and treatment platform by utilizing the advantages of both sides.

A Fluorescent Probe for Hydrogen Peroxide in Vivo Based on the Modulation of Intramolecular Charge Transfer

Abstract: Endogenous hydrogen peroxide in vivo is related to many diseases, including cancer, diabetes, cardiovascular disease, and neurodegenerative disorders. Although many probes for detection of H2O2 have been explored, rapid response probes are still expected for in vivo application. Here, a new probe (PAM-BN-PB) was designed based on an intramolecular charge transfer (ICT) process with three parts: phenanthroimidazole, benzonitrile, and phenyl boronate. By modulation ICT process of PAM-BN-PB, H2O2 in solution systems can be detected with good selectivity. The exogenous and endogenous H2O2 in normal living cells, ischemia-reperfusion injury cells, and animals all can be imaged by PAM-BN-PB.

Core-Shell Gold Nanorod@Layered Double Hydroxide Nanomaterial with Highly Efficient Photothermal Conversion and Its Application in Antibacterial and Tumor Therapy.

Abstract: Photothermal conversion efficiency (η) of gold nanorods (GNRs) can be tuned by enlarging the aspect ratio and forming the core–shell structure. Herein, an easy synthesis method is developed to construct the core–shell GNR@LDH nanostructure with GNRs and layered double hydroxides (LDHs). The interaction between Au and LDHs results some electron deficiency on the surface of Au and the more electrons induce more thermal energy conversion. The η value of GNR@LDH can reach up to 60% under the 808 nm laser irradiation, which is a significant enhanced conversion efficiency compared with the reported GNR-based photothermal therapy materials. CTAB (cetyltrimethyl ammonium bromide) can be replaced totally during the synthesis process, and GNRs maintain a good dispersion in LDHs. This core–shell composite GNR@LDH can be applied in photothermal, antibacterial, tumor therapy and biological imaging with low dosage and nontoxicity.

Portable and smart devices for monitoring heavy metal ions integrated with nanomaterials

Abstract: With increasing concerns of ecological environment, safe drinkable water and healthy food, the detection for heavy metal ions (HMIs) becomes an attractive research field. On the basis of optical, electrical and other signals from nanomaterials, many interesting methods and portable devices for detection of HMIs are growing flourishingly. In this review, we focus on the portable and smart devices integrated with nanomaterials for monitoring HMIs. The interesting design of the miniaturization, portability, and commercialization of HMIs detection devices are summarized and introduced comprehensively.

Enhancement of the Aggregation-Induced Emission by Hydrogen Bond for Visualizing Hypochlorous Acid in an Inflammation Model and a Hepatocellular Carcinoma Model.

Abstract: As an important reactive oxygen species, hypochlorous acid (HClO) is produced in various physiological processes. The abnormal rise of the HClO level is associated with a large number of inflammatory diseases. In this work, we develop a simple, aqueous-soluble aggregration-induced emission (AIE) probe for sensing HClO with significant aggregation-induced fluorescence (>1000 times). Two probes, CH3O-TPE-Py+-N+ (COTN) and OH-TPE-Py+-N+ (HOTN) (TPE, tetraphenylethylene), are synthesized for sensing HClO by the cleavage of the Py+-N+ group; the reaction products are CH3O-TPE-CHO (COT) and OH-TPE-CHO (HOT), respectively. The hydrophobicity of the probes is changed with the increased aggregation-induced emission. During the process, HOTN shows significantly better response than COTN. The slightly different chemical structures of COTN and HOTN result in a significant response to HClO. The theoretical calculation data support the theory that the hydrogen bond contributes to the excellent sensitivity for HClO. On the basis of the good response to HClO in vitro, HOTN is used to image inflammation and hepatocellular carcinoma in vivo because these diseases always produce high HClO levels.

Principles Of Fluorescence Spectroscopy

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Nanozymes: Classification, Catalytic Mechanisms, Activity Regulation, and Applications

Abstract: Because of the high catalytic activities and substrate specificity, natural enzymes have been widely used in industrial, medical, and biological fields, etc. Although promising, they often suffer from intrinsic shortcomings such as high cost, low operational stability, and difficulties of recycling. To overcome these shortcomings, researchers have been devoted to the exploration of artificial enzyme mimics for a long time. Since the discovery of ferromagnetic nanoparticles with intrinsic horseradish peroxidase-like activity in 2007, a large amount of studies on nanozymes have been constantly emerging in the next decade. Nanozymes are one kind of nanomaterials with enzymatic catalytic properties. Compared with natural enzymes, nanozymes have the advantages such as low cost, high stability and durability, which have been widely used in industrial, medical, and biological fields. A thorough understanding of the possible catalytic mechanisms will contribute to the development of novel and high-efficient nanozymes, and the rational regulations of the activities of nanozymes are of great significance. In this review, we systematically introduce the classification, catalytic mechanism, activity regulation as well as recent research progress of nanozymes in the field of biosensing, environmental protection, and disease treatments, etc. in the past years. We also propose the current challenges of nanozymes as well as their future research focus. We anticipate this review may be of significance for the field to understand the properties of nanozymes and the development of novel nanomaterials with enzyme mimicking activities.

Recent Strategies to Develop Innovative Photosensitizers for Enhanced Photodynamic Therapy.

Abstract: This review presents a robust strategy to design photosensitizers (PSs) for various species. Photodynamic therapy (PDT) is a photochemical-based treatment approach that involves the use of light combined with a light-activated chemical, referred to as a PS. Attractively, PDT is one of the alternatives to conventional cancer treatment due to its noninvasive nature, high cure rates, and low side effects. PSs play an important factor in photoinduced reactive oxygen species (ROS) generation. Although the concept of photosensitizer-based photodynamic therapy has been widely adopted for clinical trials and bioimaging, until now, to our surprise, there has been no relevant review article on rational designs of organic PSs for PDT. Furthermore, most of published review articles in PDT focused on nanomaterials and nanotechnology based on traditional PSs. Therefore, this review aimed at reporting recent strategies to develop innovative organic photosensitizers for enhanced photodynamic therapy, with each example described in detail instead of providing only a general overview, as is typically done in previous reviews of PDT, to provide intuitive, vivid, and specific insights to the readers.

Design of superior phototheranostic agents guided by Jablonski diagrams

Abstract: Phototheranostics represents a promising direction for modern precision medicine, which has recently attracted great research interest from multidisciplinary research areas. Organic optical agents including small molecular fluorophores, semiconducting/conjugated polymers, aggregation-induced emission luminogens, etc. with tuneable photophysical properties, high biosafety and biocompatibility, facile processability and ease of functionalization have delivered encouraging performance in disease phototheranostics. This review summarizes the recent progress of organic phototheranostic agents with an emphasis on the main strategies to manipulate the three excitation energy dissipation pathways, namely, radiative decay, thermal deactivation, and intersystem crossing, with the assistance of a Jablonski diagram, which particularly showcases how the Jablonski diagram has been guiding the design of organic agents from molecule to aggregate levels to promote the disease phototheranostic outcomes. Molecular design and nanoengineering strategies to modulate photophysical processes of organic optical agents to convert the absorbed photons into fluorescent/phosphorescent/photoacoustic signals and/or photodynamic/photothermal curing effects for improved disease phototheranostics are elaborated. Noteworthily, adaptive phototheranostics with activatable and transformable functions on demand, and regulation of excitation such as chemiexcitation to promote the phototheranostic efficacies are also included. A brief summary with the discussion of current challenges and future perspectives in this research field is further presented.