Wood-Derived Carbon Materials and Light-Emitting Materials

Wood is a sustainable and renewable material that naturally has a hierarchical structure. Cellulose, hemicellulose, and lignin are the three main components of wood. The unique physical and chemical properties of wood and its derivatives endow them with great potential as resources to fabricate advanced materials for use in bioengineering, flexible electronics, and clean energy. Nevertheless, comprehensive information on wood-derived carbon and light-emitting materials is scarce, although much excellent progress has been made in this area. Here, the unique characteristics of wood-derived carbon and light-emitting materials are summarized, with regard to the fabrication principles, properties, applications, challenges, and future prospects of wood-derived carbon and light-emitting materials, with the aim of deepening the understanding and inspiring new ideas in the area of advanced wood-based materials.

Facile synthesis of noncytotoxic PEGylated dendrimer encapsulated silver sulfide quantum dots for NIR-II biological imaging

Near-infrared-II (NIR-II, 1000-1700 nm) bioimaging features high penetration depth and high spatio-temporal resolution compared to traditional fluorescence imaging, but the key is to develop stable and biocompatible NIR-II fluorophores suitable for in vivo applications. Silver sulfide quantum dots (Ag2S QDs) have been demonstrated to be excellent for in vivo NIR-II imaging with unique optical properties and decent biocompatibility, but they often require complex post modifications for in vivo applications. Herein we demonstrate a facile one-pot strategy to synthesize PEGylated dendrimer-encapsulated Ag2S QDs useful for in vivo NIR-II imaging. Silver ions were first loaded into the core of an acylthiourea-functionalized dendrimer (PEG-PATU) through coordination between silver ions and acylthiourea groups, followed by the addition of sodium sulfide to form Ag2S QDs in situ. The resulting PEG-PATU Ag2S QDs exhibit excellent NIR-II fluorescence signals, and thus could be used for high efficiency labelling and tracking of A549 cancer cell mobility in vivo and real time visualization of the vast circulatory network of a mouse.

Tracing multi-isotopically labelled CdSe/ZnS quantum dots in biological media

The strengths and limits of isotopically labelled Engineered Nanoparticles (spiked ENPs) spread in biological media have been assessed. Multi-spiked CdSe/ZnS quantum dots (QDs), measuring 7 nm and coated with thioglycolic acid (TGA), were synthesized and enriched in 68Zn, 77Se and 111Cd. These QDs were dispersed at very low concentrations (0.1 to 5000 ppt) in diverse biological matrices (synthetic saliva, synthetic urine, plasma and Dulbecco's phosphate buffered saline - DPBS growth medium) and the isotopic compositions were determined by HR-ICP-MS. The initial QDs concentrations were calculated to assess the limit of quantification (QD-LOQ) according to the matrix and the isotopically enriched element. The obtained results demonstrated the advantages of the isotopic labelling method in order to work at very low concentrations: the QD-LOQ values for the spiked Zn, Cd and Se originated from the QDs were 10, 0.3 and 6 ppt, respectively, which is below the conventional LOQ of the HR-ICP-MS used (30, 3 and 60 ppt for Zn, Cd and Se, respectively). Conversely, in complex matrices such as saliva, urine, plasma and DPBS growth medium, the QD-LOQ values increased significantly, with values ranging from 16 to 32 ppt for Cd, 446 to 10598 ppt for Zn and 1618 to 8317 ppt for Se. These QD-LOQs are dependent on factors as the elemental background concentration already present in the matrices, and the dilution factor. In this study, the QD-LOQs are expressed for the first time with respect to the background concentration in biological media (QD-RLOQ), which can be used to better assess and then predict the efficiency of the spiking method.

Synthesis of Biocompatible Cholesteryl-Carboxymethyl Xylan Micelles for Tumor-Targeting Intracellular DOX Delivery

Patients with cancer suffer from severe side effects and reduced life quality, as chemotherapeutic drugs are cytotoxic toward normal cells as well as toward cancer cells. In recent years, nanoparticles have been explored as targeted drug delivery systems; however, problems such as toxicity and instability prevent their practical application. Here, we report the synthesis of cholesteryl-carboxymethyl xylan (CCMX) via an esterification reaction between the carboxyl group of carboxymethyl xylan and the hydroxyl group of cholesterol to form biocompatible micelles as a vehicle for targeted drugs. With its critical micelle concentration (CMC) depending on the degree of substitution (DS) of cholesteryl and ranging from 0.0024 to 0.017 mg/mL, CCMX could self-assemble and form nanoscale micelles in aqueous media. Taking doxorubicin (DOX) as a model drug, the drug encapsulation efficiency (EE%) of CCMX-3 (DS of 0.35 for cholesteryl) reached 91.3%, and this system exhibited excellent internalization ability, as verified by tumor cellular uptake tests. The results of in vitro cytotoxicity and in vivo antitumor activity tests of nude mice demonstrated that CCMX-3/DOX micelles effectively suppressed the growth of tumor cells by maintaining the cytotoxicity of commercial DOX injection while reducing the toxicity against normal cells and increasing the survival time.

Lead Halide Perovskite Nanocrystals-Phospholipid Micelles and Their Biological Applications: Multiplex Cellular Imaging and in Vitro Tumor Targeting

Lead halide perovskite nanocrystals (NCs) are promising optical materials in many fields. However, their poor moisture stability, significant toxicity, and difficulty to be further functionalized greatly hinder their applications in bioimaging. Here, a universal strategy is demonstrated by simply encapsulating CsPbX₃ (X = Cl, Br, I) NCs into phospholipids to achieve CsPbX₃-phospholipid micelles (CsPbX₃@phospholipid) as probes for multiplex encoding cellular imaging or tumor-targeted imaging. The layer of phospholipids endows CsPbX₃ NCs with superior water-resistant characteristics, the ability to be further biofunctionalized, and greatly improved biocompatibility. The CsPbX₃@phospholipid micelles exhibited strong luminescence with narrow fwhm in water for more than four months. Specifically, even after being modified with folic acid, the bright fluorescence of the micelles was well retained, which were employed for the targeting of Hela cells. Finally, the greatly reduced toxicity of the CsPbX₃@phospholipid micelles was verified using HeLa cells and zebrafish as in vitro and in vivo models, respectively.

Biochemistry and biomedicine of quantum dots: from biodetection to bioimaging, drug discovery, diagnostics, and therapy

According to recent research, nanotechnology based on quantum dots (QDs) has been widely applied in the field of bioimaging, drug delivery, and drug analysis. Therefore, it has become one of the major forces driving basic and applied research. The application of nanotechnology in bioimaging has been of concern. Through in vitro labeling, it was found that luminescent QDs possess many properties such as narrow emission, broad UV excitation, bright fluorescence, and high photostability. The QDs also show great potential in whole-body imaging. The QDs can be combined with biomolecules, and hence, they can be used for targeted drug delivery and diagnosis. The characteristics of QDs make them useful for application in pharmacy and pharmacology. This review focuses on various applications of QDs, especially in imaging, drug delivery, pharmaceutical analysis, photothermal therapy, biochips, and targeted surgery. Finally, conclusions are made by providing some critical challenges and a perspective of how this field can be expected to develop in the future.

STATEMENT OF SIGNIFICANCE

Quantum dots (QDs) is an emerging field of interdisciplinary subject that involves physics, chemistry, materialogy, biology, medicine, and so on. In addition, nanotechnology based on QDs has been applied in depth in biochemistry and biomedicine. Some forward-looking fields emphatically reflected in some extremely vital areas that possess inspiring potential applicable prospects, such as immunoassay, DNA analysis, biological monitoring, drug discovery, in vitro labelling, in vivo imaging, and tumor target are closely connected to human life and health and has been the top and forefront in science and technology to date. Furthermore, this review has not only involved the traditional biochemical detection but also particularly emphasized its potential applications in life science and biomedicine.

Color-tunable AIE-active conjugated polymer nanoparticles as drug carriers for self-indicating cancer therapy via intramolecular FRET mechanism

In this paper, two novel AIE-active conjugated polymers were synthesized by Pd-catalyzed Suzuki coupling polymerization reaction.

Antioxidant nanomaterials in advanced diagnoses and treatments of ischemia reperfusion injuries

Organ ischemia with inadequate oxygen supply followed by reperfusion (which initiates a complex of inflammatory responses and oxidative stress) occurs in different clinical conditions and surgical procedures including stroke, myocardial infarction, limb ischemia, renal failure, organ transplantation, free-tissue-transfer, cardiopulmonary bypass, and vascular surgery. Even though pharmacological treatments protect against experimental ischemia reperfusion (I/R) injury, there has not been enough success in their application for patient benefits. The main hurdles in the treatment of I/R injury are the lack of diagnosis tools for understanding the complicated chains of I/R-induced signaling events, especially in the acute phase after ischemia, determining the affected regions of the tissue over time, and then, targeting and safe delivery of antioxidants, drugs, peptides, genes and cells to the areas requiring treatment. Besides the innate antioxidant and free radical scavenging properties, some nanoparticles also show higher flexibility in drug delivery and imaging. This review highlights three main approaches in nanoparticle-mediated targeting of I/R injury: nanoparticles (1) as antioxidants for reducing tissue oxidative stress, (2) for targeted delivery of therapeutic agents to the ischemic regions or cells, and (3) for imaging I/R injury at the molecular, cellular or tissue level and monitoring its evolution using contrasts induced by nanoparticles. These approaches can also be combined to realize so called theranostics for providing simultaneous diagnosis of ischemic regions and treatments by targeted delivery.