Coumarin-Modified Starch Fluorescent Nanoparticles as Sensor of Fe3+ and Zn2+ ions Utilizing Dynamic Quenching and Chelation Mechanisms.

Zinc and iron are two essential trace minerals that play a pivotal role in maintaining optimal health and well-being in the human body. Despite being required in relatively small quantities, their significance can be understated as they participate in a wide array of critical physiological processes such as oxygen transport, DNA synthesis, controlling nutrient availability, etc. Understanding the distribution and behavior of these ions in natural water bodies is essential for assessing water quality, studying ecological processes, and managing environmental impacts. In this study, we have developed a dual fluorescence probe using starch which was functionalized with coumarin derivatives, for efficient detection of Fe3+ and Zn2+ ions. This structure led a self-assembled starch/coumarin (SC) fluorescent nanoparticles with strong fluorescence intensity under ultraviolet light (365 nm). The quenching effect of Fe3+ on the SC fluorescent probe enabled efficient specific detection of Fe3+. Furthermore, Zn2+ ions increased fluorescence intensity of coumarin compounds (λemission = 459). This phenomenon occurs when the coumarin compound forms a complex or interacts with the zinc ion, resulting in enhanced fluorescence emission. In summary, the developed fluorescent probe offered a promising approach for sensitive and specific detection of iron and zinc ions in aqueous solutions.

Adsorption kinetics of methylene blue from wastewater using pH-sensitive starch-based hydrogels.

In this work, starch/poly(acylic acid) hydrogels were synthesized through a free radical polymerization technique. The molar ratios of acrylic acid to N,N'-methylenebisacrylamide were 95:5, 94:6, and 93:7. The samples exhibited an amorphous porous structure, indicating that the size of the pores was contingent upon the amount of cross-linking agent. The quantity of acrylic acid in structure rose with a little increase in the amount of the cross-linking agent, which improved the hydrogels' heat stability. The swelling characteristics of the hydrogels were influenced by both the pH level and the amount of cross-linking agent. The hydrogel with a ratio of 94:6 exhibited the highest degree of swelling (201.90%) at a pH of 7.4. The dominance of the Fickian effect in regulating water absorption in the synthesized hydrogels was demonstrated, and the kinetics of swelling exhibited agreement with Schott's pseudo-second order model. The absorption of methylene blue by the hydrogels that were developed was found to be influenced by various factors, including the concentration of the dye, the quantity of the cross-linking agent, the pH level, and the duration of exposure. The hydrogel 95:5 exhibited the highest adsorption effectiveness (66.7%) for the dye solution with a concentration of 20 mg/L at pH 10.0. The examination of the kinetics and isotherms of adsorption has provided evidence that the process of physisorption takes place on heterogeneous adsorbent surfaces and can be explained by an exothermic nature.

Synthesis and characterization of fluorescence poly(amidoamine) dendrimer-based pigments.

In this work, we looked at how to make fluorescence hybrid poly(amidoamine) dendrimer (PAMAM) dendrimers using calcozine red 6G and coumarin end groups. After synthesis of ethylenediamine (EDA)-cored 4th generation PAMAM dendrimer (G4.0), surface functional groups is reacted with calcozine red 6G (Rh6G) and 7-methacryloyloxy-4-methylcoumarin. Fourier transform infrared spectroscopy, proton nuclear magnetic resonance (1H NMR), and X-ray diffraction are used to characterize the structure of synthesized fluorescent hybrid dendrimers. Optical properties are demonstrated using a fluorescence spectrophotometer, and UV-Vis-NIR reflectance spectra. According to UV-Vis-NIR reflectance spectra, hybrid dendrimers were transparent in the NIR range. Moreover, quantum yield (Φs) of hybrid dendrimers was calculated in dimethylformamide (DMF), ethanol, dimethyl sulfoxide (DMSO), and distilled water (H2O). Dendrimers in which Rh6G was utilized to modification showed the maximum quantum yield in ethanol due to great interaction of structure with ethanol and the arrangement of ring-opened amide shape of calcozine red 6G.

Reflectance and photophysical properties of rhodamine 6G/2-(4-methyl-2-oxo-2H-chromen-7-yloxy) acetic acid as cold hybrid colorant.

Rhodamine 6G (Rh6G) is modified by ethylenediamine to obtain rhodamine with amine functional groups (Rh6G-NH2). Rh6G-NH2 as an initial core is used to bond coumarin derivatives. Synthesized fluorescent colorants are specified using Fourier transform infrared spectroscopy (FT-IR), proton and carbon nuclear magnetic resonance (1H NMR and 13C NMR), X-ray diffraction (XRD), and field emission scanning electron microscopy (FE-SEM) to analyze the structure of the fluorescent pigments. Fluorescence microscopy, fluorescence spectrophotometer, and UV-visible-NIR reflectance spectra are used to demonstrate the optical properties. UV-Vis-NIR reflectance spectra showed that synthesized colorants were transparent in NIR region. Also, photophysical properties of 2-(4-methyl-2-oxo-2H-chromen-7-yloxy) acetic acid (MOHCYAA), Rh6G-NH2, and hybrid 2-(4-methyl-2-oxo-2H-chromen-7-yloxy) acetic acid/rhodamine 6G (HMR) were investigated. Type of solvent had a strong effect on quantum yield. Rh6G-NH2 (ϕs = 0.66) and HMR (ϕs = 0.72) displayed the maximum quantum yield in ethanol due to good interaction with ethanol and the formation of ring-opened amide form of rhodamine group. Finally, Rh6G-NH2 and HMR displayed the maximum quantum yield in ethanol due to good interaction of structure with ethanol and the formation of ring-opened amide form of rhodamine group in compound.

UV-stabilized self-assembled amphiphilic triblock terpolymers supramolecular structures with low cytotoxicity as doxorubicin carriers.

Amphiphilic polystyrene-b-poly[(7-(Allyloxy)-2H-chromen-2-one)-co-(2-hydroxyethyl methacrylate)]-b-poly(2-(dimethylamino)ethyl methacrylate) (PS-b-P(AC-co-HEMA)-b-P(DMAEMA)) triblock terpolymers were synthesized by atom transfer radical polymerization (ATRP). PS-b-P(AC-co-HEMA)-b-PDMAEMA triblock terpolymers were characterized using proton nuclear magnetic resonance (1H NMR) and gel permeation chromatography (GPC). The effect of various pH values on solution self-assembly behavior of PS-b-P(AC-co-HEMA)-b-P(DMAEMA) triblock terpolymers was investigated. Field emission scanning electron microscopy (FE-SEM), transmission electron microscopy (TEM), fluorescence microscopy, and dynamic light scattering (DLS) were used to observe the size and morphology of the assembled triblock terpolymers. With altering pH value, different morphologies were obtained including spherical micelles, Janus snowman, and spherical Janus as well as cubic-hexagonal structures. UV light was used to stabilize the self-assembled morphologies and FE-SEM results showed that morphology remained unchanged after photo-dimerization. The self-assembled triblock terpolymers before and after photo-crosslinking were loaded with doxorubicin (DOX) and drug release behavior was examined at different conditions. Due to photo-crosslinking of self-assembled terpolymers, cumulative release was decreased. Thus, they might be more controllable drug carriers in drug delivery systems.

Synthesis and characterization of poly(propylene imine)-dendrimer-grafted gold nanoparticles as nanocarriers of doxorubicin.

The aim of current work is synthesis 4th-generation-poly(propylene imine) (PPI)-dendrimer modified gold nanoparticles (Au-G4A) as nanocarriers for doxorubicin (DOX) and studying in vitro drug release kinetics from nanocarriers into different media. Accordingly, AuNPs were synthesized by reduction of chloroauric acid (HAuCl4) aqueous solution with trisodium citrate and modified with cysteamine to obtain amine-functionalized (Au-NH2) nanoparticles. Au-NH2 nanoparticles were used as multifunctional cores and participated in Michael addition of acrylonitrile and reduction process by lithium aluminum hydride (LAH) to synthesize Au-G4A nanoparticles. Also, peripheral primary amine groups of Au-G4A were conjugated with folic acid (FA) (Au-G4F) to study the bioconjugation effect on drug release behavior of nanostructures. Ultraviolet spectroscopy (UV-vis), atomic force microscopy (AFM), transmission electron microscopy (TEM), Fourier transform infrared spectroscopy (FT-IR), and thermal gravimetric analysis (TGA) were used to approve the synthesis of different nanostructures. Finally, Au-G4A and Au-G4F samples were loaded with DOX and exposed to environments with different pH values to examine the release properties of nanostructures. Also, drug release kinetics was investigated by fitting of experimental data with different release models. As a result, synthesized dendritic structures showed Higuchi and Korsmeyer-Peppas models release behavior due to better solubility of drug in release media with respect to dendrimer cavities and drug release through polymeric matrix respectively.