Preparation of Self-Healing Anthocyanidin-Containing Thermochromic Alginate Ink for Authentication Purposes.

Thermochromic inks have proven to be a promising security encoding approach for making commercially available products less susceptible to forgery. However, thermochromic inks have been plagued with poor durability. Thus, self-healable hydrogels can be used as self-repair inks with better durability. Herein, we combined hybrid cellulose nanofibers (CNFs) and sodium alginate (SA) with anthocyanidin(Cy)-based Brassica oleracea L. var. capitata extract in the existence of mordant (ferrous sulfate) to create a self-healing ink for authentication. CNFs were used as a reinforcement agent to enhance the mechanical strength of the sodium alginate hydrogel. Both durability and thermal stability were ensured using self-healing inks. Red cabbage was used to extract Cy-based chromophore as an environmentally friendly spectroscopic probe for immobilization into SA. Using varying concentrations of anthocyanidin, self-healable composite hydrogels (Cy@SA) with thermochromic properties were provided. Using the CIE Lab color coordinate system, homogeneous purple (569 nm) films were printed onto a sheet surface. Upon heating from 25 to 70 °C, the purple color changed to red (433 nm). Transmission electron microscopy was applied to study anthocyanidin/mordant (Cy/M) nanoparticles (NPs). The properties of the applied prints were analyzed using several methods. Both the hydrogel and stamped sheets were tested for their mechanical and rheological characteristics, respectively. Research on the nanocomposite ink (Cy@SA) antibacterial properties and cytotoxicity was also conducted.

C3-Spirooxindoles: Divergent chemical synthesis and bioactivities (2018-2023).

This scientific review documents the recent progress of C3-spirooxindoles chemistry (synthesis and reaction mechanism) and their bioactivities, focusing on the promising results as well as highlighting the biological mechanism via the reported molecular docking findings of the most bioactive derivatives. C3-Spirooxindoles are attractive bioactive agents and have been found in a variety of natural compounds, including alkaloids. They are widely investigated in the field of medicinal chemistry and play a key role in medication development, such as antivirals, anticancer agents, antimicrobials, etc. Regarding organic synthesis, several traditional and advanced strategies have been reported, particularly those that started with isatin derivatives.

Immobilization of biomolecular anthocyanin natural sensor into plasma-cured polyethylene terephthalate fibers from recycled plastic waste for determination of ammonia.

Polyester textiles have been applied in numerous industrial applications. Polyester fibers are characterized with being excellent insulators to electricity, having excellent flexural and impact strength, ease of manufacture, low-cost, as well as having resistance to moisture and chemicals. However, polyester fibers cannot be stained due to the absence of active dyeing sites on the surface of the fibrous structure. Thus, polyester cannot be dyed after it has been extruded. Herein, we report the development of novel-colored polyester fabrics using plasma-assisted dyeing and anthocyanin natural probe for determination of ammonia that may cause severe harmful effects to human organs and even death. Anthocyanin was extracted from red cabbage and characterized. The water-soluble anthocyanin was fastened to polyester fibers by mordant (potash alum) to generate anthocyanin-mordant coordinative complex nanoparticles. Polyester can be treated with thin layer of anthocyanin probe after activation with plasma. The results showed excellent colorfastness, ultraviolet blocking, and antibacterial performance of the anthocyanin-dyed polyester (APET) fibers. The APET fibers showed great potential for developing a portable colorimetric device for an on-site detection of ammonia. APET displayed a detection limit of aqueous ammonia in the range of 25-200 ppb, displaying a change in color from purple (542 nm) to white (387 nm).

Superficial and Inkjet Scalable Printed Sensors Integrated with Iron Oxide and Reduced Graphene Oxide for Sensitive Voltammetric Determination of Lurasidone.

The present work demonstrated the fabrication and the electrochemical characterization of novel printed electrochemical sensors integrated with an innovative nanosensing platform based on the synergic electrocatalytic effect of iron oxide nanoparticles (FeONPs) and reduced graphene oxide (rGO) for precise voltammetric determination of the antipsychotic drug lurasidone hydrochloride (LUH). The features of the electrode surface fabricated using the ordinary inkjet printer were characterized by scanning electron microscopy and electrochemical impedance spectroscopy. Among different ink formulations, integration of the printing ink with the ratio 15 mg FeONPs and 20 mg rGO was found to be the most appropriate for sensitive quantification of LUH in biological fluids and pharmaceutical formulations in the presence of LUH degradation products. Under the optimized experimental and electroanalytical parameters, the recorded square-wave voltammograms were correlated to LUH within the linear concentration ranging from 50 to 2150 ng mL-1 with detection limit and limit of quantification values of 15.64 and 47.39 ng mL-1, respectively. Based on the cyclic voltammograms recorded for LUH at different scan rates, the electrode reaction was assumed to be a diffusion reaction mechanism accompanied by the transfer of two electrons/protons through the oxidation of the five-membered ring nitrogen atom as assumed by the molecular orbital calculations carried out on the LUH molecule. The C max of LUH and the efficiency of the fabricated sensors enabled their clinical application for monitoring LUH in human biological fluids and pharmaceutical formulations in the presence of degradants for diverse quality control applications and green chemistry analysis.

Preparation of carbon dots-embedded fluorescent carboxymethyl cellulose hydrogel for anticounterfeiting applications.

Fluorescent inks have been emerged as a desirable encoding technique to enhance anticounterfeiting printing of commercial goods. However, significant drawbacks with fluorescent inks, such as poor durability, low efficiency, and high cost. Herein, we describe the preparation of a self-healing authentication ink based on carboxymethyl cellulose (CMC) hydrogel immobilized with nitrogen-doped carbon dots (NCD) nanoparticles (NPs) for cutting-edge anticounterfeiting applications. Security inks that self-heal are very durable. Under ambient conditions, the prepared NCD@CMC hydrogel could self-heal with a high healing efficiency. It might stick to diverse surfaces such as plastic, glass and paper sheets. The self-healing composite ink demonstrated outstanding photostability under UV light. Straightforward and environmentally friendly method was applied on the agricultural waste of rice straw toward the production of NCD using hydrothermal carbonization in an aqueous medium, and in the presence of NH4OH as an inexpensive passivating agent. The quantum yield (QY) for NCD reached 24.09 %. Various concentrations of NCD NPs were employed to produce self-healable nanocomposite inks with a variety of emission properties. Stamping homogeneous films onto paper surfaces produced a transparent layer. The CIE Lab and emission spectra of prints independently verified the capability of NCD nanocomposite inks to vary their color to blue under UV illumination. To measure the particle diameter of the prepared NCD, their morphological characteristics were examined by transmission electron microscopy (TEM) to indicate diameters of 10-25 nm. Utilizing various analytical techniques, the morphology and chemical composition of the fluorescent prints were examined. We examined the mechanical qualities of the stamped papers as well as the rheological characteristics of the ink hydrogel. Due to their colorless appearance, the excitation band of the printed films was peaked at 364 nm, while their emission was peaked at 465 nm. The current smart ink holds high potential for numerous applications like smart packaging and authentication, and shows great promise as a practical and mass production approach for easily creating anticounterfeiting stamps.

Preparation of Lighting in the Dark and Photochromic Electrospun Glass Nanofiber-Reinforced Epoxy Nanocomposites Immobilized with Alkaline Earth Aluminates.

Alkaline earth aluminates (AEAs) as photoluminescent agents and silicon dioxide-based electrospun glass nanofibers with an average diameter of 150-450 nm as a roughening agent were prepared and applied to reinforce an epoxy resin toward the development of long-persistent photoluminescent and photochromic smart materials, such as smart windows and anticounterfeiting barcodes. With the physical immobilization of lanthanide-doped aluminate nanoparticles (NPs), a light-induced luminescent transparent glass@epoxy film was developed. The glass@epoxy samples were able to alter their color to green beneath ultraviolet rays and greenish-yellow in the dark, as explored by CIE Lab and luminescence spectral analyses. The morphology of the lanthanide-doped aluminate nanoparticles (43-98 nm) was examined by transmission electron microscopy (TEM). The morphologies and chemical composition of the luminescent glass@epoxy substrates were determined by different analytical techniques. The mechanical properties of the developed photoluminescent glass@epoxy substrates were inspected to show improved scratch resistance as compared to the AEA-free substrate. The photoluminescence spectra were measured to indicate the detection of two emission bands at 494 and 525 nm when excited at 365 nm. The photoluminescent glass@epoxy hybrids with lower AEA contents have showed fast reversibility of photochromism. On the other hand, the glass@epoxy substrates with higher phosphor contents underwent persistent luminescence. Results showed that the luminescent colorless glass@epoxy hybrids have enhanced superhydrophobicity and ultraviolet blocking.

Preparation of photoluminescent nanocomposite ink for detection and mapping of fingermarks.

Simple and efficient detection and mapping method based on a strong turn-on fluorescent pigment was developed for fingerprint analysis. We present a phosphor powder characterized by strong emission which is useful to achieve better fingerprint detection on multicolored or photoluminescent surfaces, such as currency notes characterized by optically changeable inks and highly fluorescent positions, because it offers better contrast and reduce the difficulty of background interference. Novel photochromic ink was prepared to establish a fingerprinted colorless film onto cellulose documents with green emission for anticounterfeiting applications as illustrated by photoluminescence spectra. Inorganic/organic nanoscale composite ink was prepared from rare-earth doped aluminate phosphor nanoparticles (PNPs; 27-49 nm) dispersed in a polyacrylic acid binding agent. PNPs were dispersed efficiently in polyacrylic acid to generate a colorless mark. The produced photochromic inks were spray-coated onto off-white paper sheets enclosing invisible fingermarks, and then exposed to thermofixation. Photochromic film was detected on paper surface presenting a transparent appearance under visible daylight and switchable to green under UV light. The CIE Lab parameters and photoluminescence spectra were studied under visible light and ultraviolet irradiation. The fingerprinted sheets showed fluorescence band at 517 nm upon excitation at 366 nm, showing a bathochromic shift and reversible photochromism without fatigue. The morphologies of pigment phosphor particles and fingerprinted sheets were inspected. The rheological properties of ink and mechanical behavior of the fingerprinted paper samples were explored. HIGHLIGHTS: Novel smart ink with alkaline-earth aluminate and polyacrylic acid was developed. Dual-mode fluorescent photochromism was presented for latent fingerprint analysis. Off-white fingerprinted films under daylight showed color change to green under UV. Fluorescence band monitored at 517 nm upon excitation at 366 nm. Fluorescent fingermark on paper sheets demonstrated good photostability.

Synthesis and Self-assembly of Novel Nanofeather-like Fluorescent Alkyloxy-Containing Diphenyl Ether Organogelators.

In this study, novel fluorescent low molecular-weight organogelators are derived from diphenyl ethers and substituted with para-alkoxy groups of different aliphatic chain lengths. The present research promotes the preparation of innovative nanofeather-like assemblies from the synthesized diphenyl ether-derived organogelators. The gelation performance of the prepared alkoxy-substituted diphenyl ethers was reported. The synthesis procedure was achieved by using a base-catalyzed reaction of hydroxyl-substituted diphenyl with various alcohols of different aliphatic chain lengths. The chemical structures of the synthesized diphenyl ether derivatives were studied by 1H/13C NMR and infrared spectroscopy. Fluorescence and UV-vis absorption spectral analyses showed solvatochromism. The diphenyl ether derivatives with longer alkoxy terminal substituents showed enhanced thermoreversible gelation activity as compared to the diphenyl ether derivatives with shorter alkoxy terminal substituents. The morphological properties of the self-assembled diphenyl ethers were studied by transmission electron microscopy and scanning electron microscopy, which showed supramolecular architectures of highly ordered nanofeathers, enforced by van der Waals interactions and π-stacks. Depending on the length of the aliphatic tail, different morphologies were detected, including nanofeathers, nanofibers, and nanosheets. The antimicrobial and cytotoxic properties of the prepared diphenyl ether-derived organogelators were examined to confirm their possible use in various fields like drug delivery systems.

Development of Thermochromic Ink Using the Anthocyanidin-Based Red-Cabbage Extract for Anticounterfeiting Applications.

Temperature-driven colorful switching inks have been an interesting security encoding method to improve the anticounterfeiting properties of commercially available merchandise. Recently, thermochromic inks have faced many disadvantages, such as low efficiency, high cost, and low durability. In the current study, we developed self-healable ink from poly(2-acrylamido-2-methyl-1-propanesulfonic acid) (PAMPSA) integrated with the anthocyanidin(ACY)-based red-cabbage extract in the presence of ferrous sulfate for authentication purposes. Self-healable inks have been able to guarantee durability and thermal stability. Environmentally friendly, ACY-based chromophore was extracted from Brassica oleracea L. var. Capitata (red-cabbage) to serve as a spectroscopic probe immobilized into PAMPSA. The prepared self-healable nanocomposite ink (PAMPSA-ACY) displayed temperature-induced chromism with high reversibility and thermal stability. Different self-healable nanocomposite inks of thermochromic features were prepared employing different ratios of the ACY-based red-cabbage extract. As described by Commission Internationale de L'éclairage Lab coordinates, homogeneous films were stamped on the paper surface to show a purple color (631 nm) able to switch color into red (458 nm) with the increase in temperature from 25 to 65 °C, respectively. Transmission electron microscopy, infrared spectra (FT-IR), energy-dispersive X-ray, and scanning electron microscopy were utilized to inspect the morphological behavior and chemical compositions of thermochromic prints. Both mechanical and rheological properties of ink-printed paper substrates and ink solution were also investigated. Both of antimicrobial activity and cytotoxicity study of the nanocomposite ink (PAMPSA-ACY) were also evaluated. Various industries can take the advantage of the current ink as a competent approach for anticounterfeiting purposes.