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Hyaluronic Acid-zinc Protoporphyrin Conjugates for Photodynamic Antitumor Therapy
摘要： Zinc (II) protoporphyrin IX (ZnPP) strongly inhibits antioxidative enzyme heme oxygenase-1 (HO-1), and ZnPP generates reactive oxygen species (ROS) upon light irradiation. ZnPP can induce lethal oxidative stress in the tumor, when ZnPP is selectively delivered to the tumor followed by light irradiation. In this study, ZnPP was conjugated to hyaluronic acid (HA-ZnPP) for improving its solubility in aqueous media and tumor selective delivery of ZnPP by the enhanced permeability and retention (EPR) effect. Though photosensitizing activity of the HA-ZnPP was quenched in phosphate buffered saline, it was partially recovered by addition of lecithin. Similar to other polymer-conjugated ZnPP, cellular uptake of the HA-ZnPP was lower than that of the free ZnPP in HeLa cells. In tumor-bearing mice, plasma half-life of HA-ZnPP became longer than that of free ZnPP, and thus selective accumulation of the HA-ZnPP in the tumor by the EPR effect was observed. Combination of the HA-ZnPP and light irradiation potentially suppressed the tumor growth, approximately 60% tumor volume reduction was observed without apparent adverse effects at day 31 after the drug treatment. These data demonstrate that HA is a preferable carrier for ZnPP, and the HA-conjugated ZnPP is a promising antitumor agent for photodynamic therapy.
关键词： Nanomedicine,EPR,Zinc protoporphyrin,Photodynamic therapy,Hyaluronic acid
更新于2025-09-23 15:22:29
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1,8-Naphthalimide-based fluorescent sensor with high selectivity and sensitivity for zn2+ and its imaging in living cells
摘要： A novel 4-amino-1, 8-naphthalimide-based fluorescent sensor with iminodiacetic acid as receptor, was developed and applied successfully to image Zn2+ in living cells. Under physiological pH conditions, it demonstrates high selectivity and sensitivity for sensing Zn2+ with about 34-fold enhancement in aqueous solution, with a characteristic emission band of 4-amino-1,8-naphthalimide with a green color centered at 550 nm.
关键词： Naphthalimide,Iminodiacetic Acid,Zinc,Fluorescent Sensor
更新于2025-09-23 15:22:29
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In-situ synthesis of gold nanocrystals anchored graphene oxide and its application in biosensor and chemical sensor
摘要： This research demonstrated the development of graphene oxide (GO)-gold nanocrystals (AuNCs) composite-modified glassy carbon electrode (GCE) for the sensitive detection of dopamine (DA), uric acid (UA), and 4-aminophenol (4-AP). The GO was synthesized by modified Hummer’s method, which was utilized to prepare GO-AuNCs composites by in situ synthesis method using sodium L(-) malate as a reducing agent. Morphological, X-ray diffraction, and spectral analysis revealed the homogeneous formation of AuNCs with high crystallinity and purity on the GO surface and the sizes of the NCs were decreased with increasing the concentrations of sodium L(-) malate. The optimal GCE/GO-AuNCs sensor exhibited excellent electrocatalytic activity towards the oxidation of DA, UA, and 4-AP. The sensor showed interference-free and selective detection of DA and UA with sensitivities of ca. 30.3 and 17.28 μA/cm2/μM, respectively, and detection limits of ca. 28 and 50 nM, respectively, with wider dynamic ranges, measured by differential pulse voltammetry (DPV) technique. Whereas, it displayed a sensitivity and detection limit of ca. 5.70 μA/cm2/mM and 0.017 nM, respectively, for the detection of 4-AP, using current density (J)-voltage (V) measurement method. The sensor also revealed excellent stability, reproducibility, and recoveries of DA, UA, and 4-AP in real samples.
关键词： dopamine,4-aminophenol,Graphene Oxide-Au nanocrystals,uric acid,electrochemical detection
更新于2025-09-23 15:22:29
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Synthesis and spectral analysis of fluorescent probes for Ce4+ and OCl? ions based on fluorescein Schiff base with amino or hydrazine structure: Application in actual water samples and biological imaging
摘要： Two Schiff base fluorescein probes (FDA, FDH) based on fluorescein-aldehyde and nitroaniline derivatives were synthesized. The effects of amino and hydrazine substituents in fluorescein backbones were examined via fluorescence and absorbance spectra. In the presence of Ce4+, the fluorescence of FDA was quenched due to the ligand to metal charge transfer (LMCT). Hypochloric acid can react with the C=N bond, and blocking the photo induced electron transfer (PET) of FDH leads to enhancement of the fluorescence. FDA showed detection limits for Ce4+ and OCl? as low as 63 nM in concentration range of 0 – 4 μM. FDH showed detection limits for OCl? as low as 0.8 μM in concentration rang 0 – 100 μM. Polyvinylidene fluoride (PVDF) membrane containing the probes were prepared for the real-time qualitative detection of Ce4+ and OCl? in real water samples. The probes were successfully applied to biological imaging in vascular smooth muscle cells (VSMCs) and are expected to find applications in biosensing.
关键词： Schiff base,Application,Nitroaniline derivatives,Hypochloric acid,Cerium ion,Fluorescein
更新于2025-09-23 15:22:29
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Oriented ZnmIn2Sm+3@In2S3 heterojunction with hierarchical structure for efficient photocatalytic hydrogen evolution
摘要： It remains a great challenge to design and prepare highly efficient semiconductor-based photocatalysts for water splitting. To achieve this goal, the design of oriented heterojunctions for efficient carrier transport and separation is a new strategy based on their conductive anisotropy. Herein, a novel oriented J-J type ZnmIn2Sm+3@In2S3 heterojunction photocatalyst with hierarchical structures is fabricated with the assistance of oxalic acid. The hierarchical structures consist of ‘flower-like’ hollow ZnmIn2Sm+3 microspheres with epitaxially grown quantum confined In2S3 along the petal rims (J-J type heterojunction). This heterojunction improves the transport and separation of the photoexcited carriers, and extends the visible-light response range. Thus, the heterojunction photocatalyst exhibits significantly enhanced photocatalytic activity with a hydrogen evolution rate of 330 μmol h-1, which is about 4 times higher than that of single ZnIn2S4. The findings provide new insights to construct efficient oriented heterojunctions for anisotropic semiconductors.
关键词： ZnmIn2Sm+3,hierarchical structures,oxalic acid,oriented heterjunctions,In2S3
更新于2025-09-23 15:21:21
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Effect of dissolved silica on photocatalytic water purification with a TiO2 ceramic catalyst
摘要： If photocatalytic water purification technologies will find practical applications, the impact of total dissolved solids in the source water on the activity of the photocatalyst must be evaluated. In this study, we evaluated the effects of SiO3 2? in water on a TiO2 ceramic photocatalyst; specifically, we determined the effects of SiO3 2? on the rate of photocatalytic degradation of formic acid (as a model contaminant) and on the rate of photocatalytic inactivation of Escherichia coli in an aqueous solution. Both the rate of formic acid degradation and the sterilization rate decreased with increasing SiO3 2? concentration. On the other hand, at a given SiO3 2? concentration, the activity of the photocatalyst did not decrease over the course of 120 h, and the surface structure of the photocatalyst did not change (i.e., no precipitate formed on the surface). The decreases in photocatalytic activity due to the presence of SiO3 2? could be recovered by flushing the experimental apparatus with distilled water. These results show that the reason for the lower photocatalytic activity in the presence of SiO3 2? than in its absence was due to adsorption of SiO3 2? onto the surface of the TiO2 photocatalyst and that SiO3 2? adsorption was an equilibrium process in water.
关键词： TiO2 ceramic photocatalyst,SiO3 2?,Photocatalysis,formic acid,E. coli
更新于2025-09-23 15:21:21
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Invisible-ink-assisted pattern and written surface-enhanced Raman scattering substrates for versatile chem/biosensing platforms
摘要： In recent years, highly sensitive surface-enhanced Raman scattering (SERS) integrated with flexible substrates has drawn increasing attention for label-free detection. In this study, an invisible ink-inspired process was developed for the fabrication of plasmonic Au-based SERS substrates through an on-site redox strategy. Tannic acid (TNA), a common green reagent, was used not only for fabricating various SERS absorbents through a confinement reduction of a Au-TNA complex, but also for supplying an amphiphilic inorganic–organic surface structure for outstanding SERS enhancement at micromolar to nanomolar concentrations for a wide range of compounds. In addition to label-free sensing, this TNA/Au-based SERS substrate provides a versatile analysis platform for studies of chemical and biological reactions. A combination of TNA ink with different metal ions allows for a reliable procedure for the synthesis of a bimetallic AuAg SERS substrate that further enhances the SERS intensity of analyte molecules and extends the lower limit of detection.
关键词： bimetallic AuAg SERS substrate,invisible ink,tannic acid,label-free detection,SERS,plasmonic Au-based SERS substrates,surface-enhanced Raman scattering
更新于2025-09-23 15:21:21
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Ratiometric Luminescent Sensor of Picric Acid based on the Dual-Emission Mixed-Lanthanide Coordination Polymer
摘要： Powerful explosive sensors play a key role in public security and environmental protection. Herein we report a series of isostructural lanthanide coordination polymers [Ln2L1.5(NMP)2]n (LnL, Ln = Eu , Gd, Tb, Dy, Ho and Er, H4L = [1,1′:4′,1″-terphenyl]-2′,4,4″,5′-tetracarboxylic acid, NMP = N-methyl-2-pyrrolidone) and mixed-Ln LnL (EuxTb1-xL, EuxGd1-xL, TbxGd1-xL and EuxTb0.02-xGd0.98L). Luminescence studies show that both H4L and GdL emit strong fluorescence and phosphorescence at 77 K while only fluorescence at room temperature, and TbL exhibits strong Tb3+ characteristic emission though the energy difference between the triplet excited state of H4L (20661 cm-1) and the 5D4 energy level of Tb3+ (20500 cm-1) is very small. By doping Eu3+ and Tb3+ into GdL, we obtained EuxTb0.02-xGd0.98L emitting warm white light. For TbL and Tb0.01Gd0.99L showing the dual-emission, upon addition of picric acid (PA) into their suspensions in Tris-HCl buffer, Tb3+ emission decreases slowly, however, the ligand-based emission is sharply quenched, rendering TbL and Tb0.01Gd0.99L excellent single-lanthanide and mixed-lanthanide ratiometric luminescence PA sensor materials, respectively.
关键词： picric acid (PA),ratiometric luminescence sensors,white light emission,metal-organic frameworks (MOFs),Coordination polymers (CPs)
更新于2025-09-23 15:21:21
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Effects of triethylamine on the imidization temperature and properties of PI adhesive
摘要： To make clear the effects of triethylamine(TEA) on the imidization temperature and properties of polyimide(PI) adhesive,precursors poly(amic acid) salt(PAAS) synthesized via 4,4-Diaminodiphenylmethane(MDA),2,2-Bis[4-(4-aminophenoxy)phenyl]propane(BAPP),3,3',4,4'-Benzophenonetetracrboxylic dianhydride(BTDA) and TEA in N-Methyl pyrrolidone (NMP) were prepared and used to obtain PI adhesive. The chemical structure of PAAS and PI films were confirmed by 1H NMR and FTIR spectroscopy. It was found that PI-2 adhesive obtained from PAAS-2( the mole ratio of TEA/repeating unite of PAA=2/1) had the best property. TGA showed that the temperature for 5% weight loss of PI-2 could achieve 497 ℃ and tensile test showed PI-2 had superior bonding strength of 14.83 MPa. In addition,the damping performance of PI-2 had a great improvement compared with PI obtained from PAA. Moreover,through the study of imidization temperature,the results suggested that PI adhesive obtained from PAAS could complete the imidization reaction at 280 ℃,which had great significance for saving energy. And PI-300 ℃(the maximum imidization temperature of which was 300 ℃) had superior thermal stability,bonding strength and damping performance simultaneously.
关键词： Imidization temperature,Bonding strength,Polyimide,Poly(amic acid) salt
更新于2025-09-23 15:21:21
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The Response of Picea abies Somatic Embryos to UV-B Radiation Depends on the Phase of Maturation
摘要： Ultraviolet-B (UV-B) radiation is a key environmental signal which initiates diverse responses that affect the metabolism, development, and viability of plants. In keeping with our previous studies, we concentrated primarily on how UV-B radiation affects Norway spruce [Picea abies (L.) Karst.] somatic embryo maturation and how phenolics and polyamines (PAs) are linked to the defense response invoked by UV-B irradiation. We treated clusters of Norway spruce embryogenic culture (EC) with UV-B during the five stages of embryo maturation (early, cylindrical, precotyledonary, cotyledonary, and mature embryos). For the first time, we take an advantage of the unique environmental scanning electron microscope AQUASEM II to characterize somatic embryos in their native state. The severity of the irradiation effect on embryonal cell viability was shown to be dependent on the intensity of radiation as well as the stage of embryo development, and might be related to the formation of protoderm. The response of early embryos was characterized by an increase in malondialdehyde (MDA), a marked decrease in PA contents and a decline in phenolics. The reduced ability to activate the defense system seems to be responsible not only for the severe cell damage and decrease in viability but also for the inhibition of embryo development. The significant reduction in spermidine (Spd), which has been reported to be crucial for the somatic embryo development of several coniferous species, may be causally linked to the limited development of embryos. The pronounced decrease in cell wall-bound ferulic acid might correspond to failure of somatic embryos to reach more advanced stages of development. Embryos at later stages of development showed stress defense responses that were more efficient against UV-B exposure.
关键词： somatic embryogenesis,polyamines,Picea abies (L.) Karst.,viability,ferulic acid
更新于2025-09-23 15:21:21