Fabrication of Carbon Dots with Singlet Oxygen Generation and Their Potential Photodynamic Therapy Applications.

Due to the unique chemical and biomedical properties of carbon dots (CDs), they have increasingly obtained the attention in many research fields, for example, bioimaging, fluorescence sensing, and drug delivery, etc. Recently, it was found that, under light excitation, CDs can also be exploited as a novel photosensitizer to prepare reactive oxygen species (ROS), which expand their applications in the field of photodynamic therapy for cancer treatment. Nevertheless, the high cost and complex fabrication approach of CDs significantly limit their applications. To address this issue, bottom-up routes usually utilize sustainable and inexpensive carbon precursor as starting materials, employed N,N-dimethylformamide (DMF) or ethanol as an environmental-friendly solvent. Bottom-up approach was energy efficient, and the purification process was relatively simple by dialysis. Therefore, carbon dots (CDs) were facilely fabricated in a one-pot solvothermal process using 1-aminoanthraquinone as a precursor, and their application as photosensitizers for in vitro antitumor cells, especially photodynamic therapy (PDT) was established. Then the photophysical and nanoscale dimensions properties of the fabricated CDs were characterized via TEM, UV-visible, fluorescence, and FT-IR spectroscopy. The synthesized N-doped CDs can easily dissolve in water, possess very low biotoxicity, yellow-light emission (maximum peak at 587 nm). More importantly, PDT studies demonstrated that the obtained CDs possess a high singlet oxygen yield of 35%, and exhibit significant phototoxicity to cancer cells upon 635 nm laser irradiation. These studies highlight that N-doped CDs can be facilely synthesized from only one precursor, and are a potentially novel theranostic agent for in vivo PDT.

Spontaneous Formation of Fluorescent Carbon Nanoparticles in Glutaraldehyde Solution and Their Fluorescence Mechanism.

Fluorescent carbon nanoparticles exhibit merits in terms of photochemical stability, functional modification flexibility and excellent biocompatibility. Currently, fluorescent carbon nanoparticles are often obtained by bottom-up or up-bottom strategies. So far, there has been no literature concerning spontaneous formation of fluorescent carbon nanoparticles. However, we have successfully found that fluorescent carbon nanoparticles can form spontaneously in the glutaraldehyde solution. Then further investigations were conducted on the storage time, pH and temperature, which could affect the fluorescence intensity of glutaraldehyde solution. The results indicate that the value of the fluorescence intensity will increase with the extension of the storage time. Moreover, the fluorescence mechanism of the glutaraldehyde solution was studied according to its properties and experiment results. Transmission electron microscopy was used to demonstrate nanoparticles in the glutaraldehyde solution. It's assumed that such phenomenon is probably attributed to the conjugated structure resulting from the polymerization of glutaraldehyde and the quantum confinement effect owing to the nanoparticles formed by the aggregation of polymers. Therefore, the spontaneous fluorescence produced by glutaraldehyde solution provides a simple and environmentally-friendly way to prepare fluorescent carbon nanoparticles.

Multifunctional N,S co-doped carbon dots for sensitive probing of temperature, ferric ion, and methotrexate.

In this paper, we have presented a facile method to fabricate nitrogen and sulfur co-doped carbon dots (N,S-CDs) for blood methotrexate (MTX) sensing applications. The N,S-CDs with quantum yield up to 75% were obtained by one-step hydrothermal carbonization, using reduced glutathione and citric acid as the precursors. With this approach, the formation and the surface passivation of N,S-CDs were carried out simultaneously, resulting in intrinsic fluorescence emission. Owing to their pronounced temperature dependence of the fluorescence emission spectra, resultant N,S-CDs can work as versatile nanothermometry devices by taking advantage of the temperature sensitivity of their emission intensity. In addition, the obtained N,S-CDs facilitated high selectivity detection of Fe3+ ions with a detection limit as low as 0.31 µM and a wide linear range from 3.33 to 99.90 µM. More importantly, the added MTX selectively led to the fluorescence quenching of the N,S-CDs. Such fluorescence responses were used for well quantifying MTX in the range of 2.93 to 117.40 µM, and the detection limit was down to 0.95 µM. Due to "inert" surface, the N,S-CDs well resisted the interferences from various biomolecules and exhibited excellent selectivity. The proposed sensing system was successfully used for the assay of MTX in human plasma. Due to simplicity, sensitivity, selectivity, and low cost, it exhibits great promise as a practical platform for MTX sensing in biological samples. Graphical Abstract.

CEACAM5 stimulates the progression of non-small-cell lung cancer by promoting cell proliferation and migration.

OBJECTIVE: To detect the expression of CEA-related cell adhesion molecule 5 (CEACAM5) in non-small-cell lung cancer (NSCLC) and explore its function in the progression and development of NSCLC. METHODS: qRT-PCR and immunohistochemistry were performed to detect CEACAM5 expression in human NSCLC tissues and cell lines. The correlation between CEACAM5 expression and the clinicopathological features of patients with NSCLC was also investigated. MTT, colony formation, wound healing, and immunoblot assays were performed to detect the functions of CEACAM5 in NSCLC cells in vitro, and immunoblotting was used to detect the effects of CEACAM5 on p38-Smad2/3 signaling. RESULTS: CEACAM5 expression was elevated in human NSCLC tissues and cells. We further found that CEACAM expression was correlated with clinicopathological features including T division, lymph invasion, and histological grade in patients with NSCLC. The in vitro assays confirmed that CEACAM5 depletion inhibited the proliferation and migration of NSCLC cells by activating p38-Smad2/3 signaling. We verified the involvement of CEACAM5 in the suppression of NSCLC tumor growth in mice. CONCLUSION: CEACAM5 stimulated the progression of NSCLC by promoting cell proliferation and migration in vitro and in vivo. CEACAM5 may serve as a potential therapeutic target for the treatment of NSCLC.

An easy synthesis of nitrogen and phosphorus co-doped carbon dots as a probe for chloramphenicol.

Heteroatom doping in carbon dots (CDs) was found to be an efficient way to regulate the structure of electronic energy levels and enhance the fluorescence characteristics of CDs. Nevertheless, most reported fabrication processes of heteroatom-doped CDs are rigorous and complex. Herein, a facile and novel strategy was developed to rapidly prepare nitrogen and phosphorus co-doped CDs (N,P-CDs) using acetic acid as the carbon source, and arginine, 1,2-ethylenediamine (EDA) and diphosphorus pentoxide as the dopants, respectively. The optical, morphological and structural characterizations of the synthesized N,P-CDs were investigated via UV and photoluminescence spectroscopy, X-ray photoelectron spectroscopy, TEM, and FT-IR spectroscopy. The N,P-CDs display outstanding fluorescence stability under high ionic strength (1.6 M KCl), and long time UV irradiation, indicating that they can be used as favorable candidates for fluorescent probes. The fluorescence of N,P-CDs was selectively quenched by chloramphenicol (CAP) with a short response time. The linear range of the response to CAP was from 0.8 to 70 µM with a limit of detection of 0.36 µM (S/N = 3). Notably, the fabricated N,P-CDs were employed for the highly selective and sensitive detection of CAP in milk samples, indicating their potential applications in biologically related areas.

Carbon nanotubes: applications in pharmacy and medicine.

Carbon nanotubes (CNTs) are allotropes of carbon, made of graphite and constructed in cylindrical tubes with nanometer in diameter and several millimeters in length. Their impressive structural, mechanical, and electronic properties are due to their small size and mass, their strong mechanical potency, and their high electrical and thermal conductivity. CNTs have been successfully applied in pharmacy and medicine due to their high surface area that is capable of adsorbing or conjugating with a wide variety of therapeutic and diagnostic agents (drugs, genes, vaccines, antibodies, biosensors, etc.). They have been first proven to be an excellent vehicle for drug delivery directly into cells without metabolism by the body. Then other applications of CNTs have been extensively performed not only for drug and gene therapies but also for tissue regeneration, biosensor diagnosis, enantiomer separation of chiral drugs, extraction and analysis of drugs and pollutants. Moreover, CNTs have been recently revealed as a promising antioxidant. This minireview focuses the applications of CNTs in all fields of pharmacy and medicine from therapeutics to analysis and diagnosis as cited above. It also examines the pharmacokinetics, metabolism and toxicity of different forms of CNTs and discusses the perspectives, the advantages and the obstacles of this promising bionanotechnology in the future.

Development of novel amphiphilic magnetic molecularly imprinted polymers compatible with biological fluids for solid phase extraction and physicochemical behavior study.

In the present work, a novel amphiphilic magnetic molecularly imprinted polymer (M-MIP) has been synthesized by a simple non covalent method for the loading of gatifloxacin (GTFX) in polar solvent. This nanomaterial used as sorbent has been applied to the solid phase extraction of GTFX in different spiked biological fluids. For the first time, studies of dispersibility and solubility behaviors with different solvents and water were performed to demonstrate amphiphilicity and also to find the better nanomaterial obtained. Fourier transform infrared (FT-IR), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and X-ray (XRD) were used to characterize the nanomaterials, and Scatchard plot analysis to demonstrate the binding kinetic. Results suggest that the dispersibility, solubility and the adsorption in water have relationships with the structure of nanomaterials prepared. The oleic acid coated on the M-MIP combined with the washing process has enhanced the amphiphilicity of the nanomaterials. The M-MIP2 showed better selectivity and adsorption behavior with imprinted efficiency higher than (2) in water, as well as in biological fluids. Moreover, no interference with constituents of blank urine and blank serum samples for solid phase extraction (SPE) was observed. Moreover, loading recovery was found higher than 95% with low RSD. The novel amphiphilic magnetic nanomaterial prepared here as sorbent is suitable for SPE of GTFX in biological fluids for therapeutic monitoring control. It could be also used as carrier in drug delivery system for experimental and clinical studies.

Anticancer loading and controlled release of novel water-compatible magnetic nanomaterials as drug delivery agents, coupled to a computational modeling approach.

The preparation, characterization and application of novel anticancer "epirubicin" (EPI) water-compatible magnetic molecularly imprinted polymers (M-MIPs) like artificial antibodies by computational design and chemical synthesis as a carrier for drug delivery is described herein. Two monomers: methacrylic acid (MAA) and methacrylamide (MAM) were selected by computational simulation from the four chemicals used. Covalent and non-covalent bonds were evaluated by this technique based on the interaction mode and energy with template or solvent. Non-covalent bonding was predominant in all cases and major energy interaction was observed. The nanomaterials were characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), Fourier transform infrared spectroscopy (FT-IR), X-ray powder diffraction (XRD), and a vibrating sample magnetometer (VSM). The loading and controlled release studies performed showed a slight advantage for the M-MIP obtained from MAA than that from MAM at ambient temperature. However, the drug release in vitro was slightly better for the second M-MIP when the temperature increased to 50 °C. The water-compatible nanomaterial showed good pH-sensitive drug release profiles in vitro. Briefly, due to its magnetic property, amphiphilicity, good biomimetic recognition of EPI, high adsorption capacity and controlled release, the epirubicin M-MIPs synthesized in this study are suitable to be applied to a magnetic targeted drug delivery system.