Exploring <i>N</i>-Imidazolyl-<i>O</i>-Carboxymethyl Chitosan for High Performance Gene Delivery

Chitosan shows good biocompatibility and biodegradability, but the poor water solubility and low transfection efficiency hinder its applications as a gene delivery vector. We here report the detailed synthesis and characterization of a novel ampholytical chitosan derivative, <i>N</i>-imidazolyl-<i>O</i>-carboxymethyl chitosan (IOCMCS), used for high performance gene delivery. After chemical modification, the solubility of the resulting polymer is enhanced, and the polymer is soluble in a wide pH range (4–10). Gel electrophoresis study reveals the strong binding ability between plasmid DNA and the IOCMCS. Moreover, the IOCMCS does not induce remarkable cytotoxicity against human embryonic kidney (HEK293T) cells. The cell transfection results with HEK293T cells using the IOCMCS as gene delivery vector demonstrate the high transfection efficiency, which is dependent on the degree of imidazolyl substitution. Therefore, the IOCMCS is a promising candidate as the DNA delivery vector in gene therapy due to its high solubility, high gene binding capability, low cytotoxicity, and high gene transfection efficiency

Colorimetric Response of Dithizone Product and Hexadecyl Trimethyl Ammonium Bromide Modified Gold Nanoparticle Dispersion to 10 Types of Heavy Metal Ions: Understanding the Involved Molecules from Experiment to Simulation

A new kind of analytical reagent, hexadecyl trimethyl ammonium bromide (CTAB), and dithizone product-modified gold nanoparticle dispersion, is developed for colorimetric response to 10 types of heavy metal ions (M^<i>n</i>+), including Cr­(VI), Cr³⁺, Mn²⁺, Co²⁺, Ni²⁺, Cu²⁺, Zn²⁺, Cd²⁺, Hg²⁺, and Pb²⁺. The color change of the modified gold nanoparticle dispersion is instantaneous and distinct for Mn²⁺, Co²⁺, Ni²⁺, Cu²⁺, Zn²⁺, Cd²⁺, Hg²⁺, and Pb²⁺. The color change results from the multiple reasons, such as electronic transitions, cation−π interactions, formation of coordination bonds, and M^<i>n</i>+-induced aggregation of gold nanoparticles (AuNPs). The different combining capacity of heavy metal ions to modifiers results in the different broadening and red-shifting of the plasmon peak of modified AuNPs. In addition, Cr­(VI), Cu²⁺, Co²⁺, Ni²⁺, and Mn²⁺ cause the new UV–vis absorption peaks in the region of 360–460 nm. The interactions between the modifiers and AuNPs, and between the modifiers and M^<i>n</i>+, are investigated by using Fourier transform infrared spectroscopy and X-ray photoelectron spectroscopy. The results confirm that AuNPs are modified by CTAB and dithizone products through electrostatic interactions and Au–S bonds, respectively, and the M^<i>n</i>+–N bonds form between M^<i>n</i>+ and dithizone products. Furthermore, the experimental and density functional theory calculated IR spectra prove that dithizone reacts with NaOH to produce C₆H₅O^– and [SCH₂N₄]^2‑. The validation of this method is carried out by analysis of heavy metal ions in tap water

A Supersensitive Probe for Rapid Colorimetric Detection of Nickel Ion Based on a Sensing Mechanism of Anti-etching

Redundant nickel is harmful to human health and can result in skin diseases, allergies, or cancer. Although many probes based on noble metal nanoparticles have been established for rapid heavy metal ion detection by the naked eye or ultraviolet–visible (UV–vis) spectroscopy, few noble metal nanomaterials have been developed for Ni²⁺ detection. In this study, we propose novel triangular silver nanoprisms (AgNPRs) stabilized with glutathione (GSH) for rapid colorimetric detection of Ni²⁺ based on a sensing mechanism of anti-etching, which has been affirmed by Raman spectra, UV–vis spectra, transmission electron microscopy, and dynamic light scattering. At the optimal experimental parameters, our GSH-AgNPR-based Ni²⁺ probe has an excellent selectivity compared with those of 26 other ions because Ni²⁺ can inhibit the AgNPR etching by iodide ion (I^–) (i.e., anti-etching) while other ions cannot. The limit of detection (LOD) of our Ni²⁺ probe is 50 nM via the naked eye and 5 nM via UV–vis spectroscopy. They are both negligible compared with the permissible limit of Ni²⁺ in drinking water (0.34 μM) prescribed by the World Health Organization. In particular, the latter is far lower than the LOD values of other reported Ni²⁺ probes based on noble metal nanomaterials. A satisfying linear relationship reinforces that our probe can be utilized for the quantitative analysis of Ni²⁺. The detection of real water samples indicates that our probe could be used for rapid Ni²⁺ colorimetric detection with supersensitivity and excellent selectivity in real environmental water samples

A Supersensitive CTC Analysis System Based on Triangular Silver Nanoprisms and SPION with Function of Capture, Enrichment, Detection, and Release

Detection of circulating tumor cells (CTCs) may be applied for diagnosis of early tumors like a liquid biopsy. However, the sensitivity remains a challenge because CTCs are extremely rare in peripheral blood. In this study, we developed a supersensitive CTC analysis system based on triangular silver nanoprisms (AgNPR) and superparamagnetic iron oxide nanoparticles (SPION) with function of capture, enrichment, detection, and release. The AgNPR was encoded with MBA (i.e., 4-mercaptobenzoic acid) and modified with rBSA (i.e., reductive bovine serum albumin) and FA (i.e., folic acid) generating organic/inorganic composite nanoparticle MBA-AgNPR-rBSA-FA, which has the function of surface-enhanced Raman scattering (SERS). The optimized SERS nanoparticles (i.e., MBA3-AgNPR-rBSA4-FA2) can be utilized for CTC detection in blood samples with high sensitivity and specificity, and the LOD (i.e., limit of detection) reaches to five cells per milliliter. In addition, the SPION was also modified with rBSA and FA generating magnetic nanoparticle SPION-rBSA-FA. Our supersensitive CTC analysis system is composed of MBA3-AgNPR-rBSA4-FA2 and SPION-rBSA-FA nanoparticles, which were applied for capture (via interaction between FA and FRα), enrichment (via magnet), and detection (via SERS) of cancer cells from blood samples. The results demonstrate that our supersensitive CTC analysis system has a better sensitivity and specificity than the SERS nanoparticles alone, and the LOD is up to 1 cell/mL. The flow cytometry and LSCM (i.e., laser scanning confocal microscope) results indicate the CTCs captured, enriched, and isolated by our supersensitive CTC analysis system can also be further released (via adding excessive free FA) for further cell expansion and phenotype identification

Ultrasmall Self-Cascade AuNP@FeS Nanozyme for H₂S‑Amplified Ferroptosis Therapy

Recently, nanozymes with peroxidase (POD)-like activity have shown great promise for ferroptosis-based tumor therapy, which are capable of transforming hydrogen peroxide (H2O2) to highly toxic hydroxyl radicals (•OH). However, the unsatisfactory therapeutic performance of nanozymes due to insufficient endogenous H2O2 and acidity at tumor sites has always been a conundrum. Herein, an ultrasmall gold (Au) @ ferrous sulfide (FeS) cascade nanozyme (AuNP@FeS) with H2S-releasing ability constructed with an Au nanoparticle (AuNP) and an FeS nanoparticle (FeSNP) is designed to increase the H2O2 level and acidity in tumor cells via the collaboration between cascade reactions of AuNP@FeS and the biological effects of released H2S, achieving enhanced •OH generation as well as effective ferroptosis for tumor therapy. The cascade reaction in tumor cells is activated by the glucose oxidase (GOD)-like activity of AuNP in AuNP@FeS to catalyze intratumoral glucose into H2O2 and gluconic acid; meanwhile, the released H2S from AuNP@FeS reduces H2O2 consumption by inhibiting intracellular catalase (CAT) activity and promotes lactic acid accumulation. The two pathways synergistically boost H2O2 and acidity in tumor cells, thus inducing a cascade to generate abundant •OH by catalyzing H2O2 through the POD-like activity of FeS in AuNP@FeS and ultimately causing amplified ferroptosis. In vitro and in vivo experiments demonstrated that AuNP@FeS presents a superior tumor therapeutic effect compared to that of AuNP or FeS alone. This strategy represents a simple but powerful method to amplify ferroptosis with H2S-releasing cascade nanozymes and will pave a new way for the development of tumor therapy

DataSheet1_Activation of peroxymonosulfate by cow manure biochar@1T-MoS2 for enhancing degradation of dimethyl phthalate: Performance and mechanism.docx

Introduction: Dimethyl phthalate (DMP) which has been widely detected in water is neurotoxic to humans and should be effectively eliminated. Persulfate-based advanced oxidation processes are considered to be reliable methods aiming at emerging contaminants degradation, while an efficient catalyst is urgently needed for the activation of the reaction. As a typical 2D material, 1T-MoS2 is expected to be applied to the activation of persulfate owing to its abundant active sites and excellent electrical conductivity. In practical applications, 1T-MoS2 has the phenomenon of reunion which affects the exposure of its catalytic sites.Methods: Therefore, in this study, we used waste cow manure as a raw material to prepare biochar and achieved high exposure of 1T-MoS2 activation sites by loading 1T-MoS2 onto the surface of cow manure biochar through hydrothermal synthesis. The prepared composite catalytic material CMB@1T-MoS2 was used to activate PMS for the degradation of DMP.Results: It was found that CMB@1T-MoS2 has better effect than CMB or 1T-MoS2 alone for the degradation of DMP, reaching 77.65% at pH = 3. Under alkaline conditions, the degradation rate of DMP was reduced due to the inhibition of the catalytic process. Among the different coexisting anions, HCO-3 interfered and inhibited the degradation process the most, leading to the lowest degradation rate of DMP with 42.45%.Discussion: The quenching experiments and EPR analysis showed that SO-4• and •OH were the main ROS in the CMB@1T-MoS2/PMS process. This study promotes the resourceful use of cow manure and is expected to provide a novel persulfate-based advanced oxidation process catalyzed by CMB@1T-MoS2 for the elimination of DMP in an aqueous environment.</p

High-Performance Colorimetric Detection of Hg²⁺ Based on Triangular Silver Nanoprisms

Mercury ion (Hg²⁺) arising from a variety of natural sources and industrial wastes has been widely recognized as one of the most hazardous pollutants. It is very important to develop highly selective and sensitive probe for rapid detection of Hg²⁺ in aquatic ecosystems. Here we propose a new strategy for high-performance colorimetric detection of Hg²⁺, i.e., anti-etching of silver nanoprisms (AgNPRs). In the absence of Hg²⁺, the AgNPRs can be etched by I^– inducing an obvious color change from blue to red. However, in the presence of Hg²⁺, the formation of Ag–Hg nanoalloy can protect the AgNPRs from I^– etching and the color remains blue. This mechanism is verified by UV–vis, TEM, DLS, and EDS. Our AgNPRs-based colorimetric probe exhibits excellent selectivity for Hg²⁺. The limit of detection (LOD) of Hg²⁺ is 30 nM by the naked eye and 3 nM by UV–vis spectroscopy, which is lower than the mercury toxic level defined by the U.S. Environmental Protection Agency (10 nM). A good linear relationship (<i>R</i>² = 0.993) between the wavelength shift and Hg²⁺ concentrations indicates that our probe can be used for the quantitative assay of Hg²⁺. The results of Hg²⁺ detection in real environmental samples indicate the feasibility and sensitivity of our probe for application in complicated environmental samples

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Enhanced Afterglow Performance of Persistent Luminescence Implants for Efficient Repeatable Photodynamic Therapy

Persistent luminescence nanoparticles (PLNPs) have been used for bioimaging without autofluorescence background interference, but the poor afterglow performance impedes their further applications in cancer therapy. To overcome the Achilles’ heel of PLNPs, herein we report the construction of injectable persistent luminescence implants (denoted as PL implants) as a built-in excitation source for efficient repeatable photodynamic therapy (PDT). The injectable ZGC (ZnGa_1.996O₄:Cr_0.004) PL implants were prepared by dissolving ZGC PLNPs in poly­(lactic-<i>co</i>-glycolic acid)/<i>N</i>-methylpyrrolidone oleosol, which demonstrated much stronger persistent luminescence (PersL) intensity and longer PersL lifetime than that of ZGC PLNPs both <i>in vitro</i> and <i>in vivo</i>. More importantly, the intratumorally fixed ZGC PL implants can serve as a built-in excitation source for repeatable light emitting diode (LED) and PersL-excited PDT upon and after periodic LED irradiation, which leads to the overall improvement of therapeutic effectiveness for efficient tumor growth suppression. This work represents efficient repeatable PDT based on the injectable yet periodically rechargeable ZGC PL implants

Glutathione-Responsive Self-Assembled Magnetic Gold Nanowreath for Enhanced Tumor Imaging and Imaging-Guided Photothermal Therapy

Designing nanomaterials with advanced functions and physical properties to improve cancer diagnosis and treatment has been an enormous challenge. In this work, we report the synthesis of magnetic gold nanowreaths (AuNWs) by combining wet-chemical synthesis with layer-by-layer self-assembly. The presence of Au branches, small junctions, and central holes in AuNWs led to improved photothermal effect compared with Au nanoring seeds and thick Au nanoring with smooth surface. The self-assembly of exceedingly small magnetic iron oxide nanoparticles (ES-MIONs) on the surfaces of AuNWs not only effectively quenched the T₁-weighted magnetic resonance imaging (MRI) ability due to the enhanced T₂ decaying effect but also provided the responsiveness to glutathione (GSH). After intravenous injection, the T₁ signal of magnetic AuNWs initially in the “OFF” state can be intelligently switched on in response to the relatively high GSH concentration in tumor, and the formation of larger assemblies of ES-MIONs improved their tumor delivery compared to ES-MIONs themselves. Thus, the magnetic AuNWs showed higher MRI contrast than ES-MIONs or commercial Magnevist in <i>T</i>₁-weighted MR imaging of tumor. Furthermore, the magnetic AuNWs have absorption in near-infrared range, leading to strong photoacoustic signal and effective photoablation of tumor. Therefore, our GSH-responsive self-assembled magnetic AuNWs could enhance T₁-weighted MRI and photoacoustic imaging of tumor and be used for imaging-guided photothermal therapy