Experimental and computational study of naphthalimide derivatives: Synthesis, optical, nonlinear optical and antiviral properties.

The nonlinear optical (NLO) and antiviral properties of naphthalimide Schiff base compounds (5a-c) were experimentally and computationally investigated. The synthesized compounds (5a-c) were successfully characterized via UV-Vis, FTIR, 1H NMR, fluorescence spectroscopy, and elemental analysis. The calculated average third-order NLO polarizabilities (˂γ˃) of 5a, 5b, and 5c were found to be 5, 9, and 21 times greater than the ˂γ˃ amplitude of p-NA, respectively. The computed results revealed the potential of the synthesized compounds for NLO applications. Additionally, molecular docking studies of the synthesized compounds with two crucial SARS-CoV-2 proteins were performed to examine their biochemical properties. Compound 5c exhibited a higher binding affinity with the spike protein compared to that with Mᴾᴿᴼ. The results obtained herein indicate the potential of the synthesized naphthalimide derivatives for optoelectronic and drug design applications.

Carbon dioxide adsorption and cycloaddition reaction of epoxides using chitosan-graphene oxide nanocomposite as a catalyst.

One of today's major challenges is to provide green materials for a cleaner environment. We have conducted studies on carbon dioxide (CO2) adsorption and conversion to valuable products by an ecofriendly approach based in chitosan/graphene oxide (CSGO) nanocomposite film. Rheological behavior indicates that the CSGO has a better solvation property than the pure chitosan. An adsorption capacity of 1.0152mmolCO2/g of CSGO nanocomposite at 4.6bar was observed. The catalytic behavior of the CSGO nanocomposite in the presence of tetra-n-butylammonium iodide (n-Bu4NI) as co-catalyst was evaluated for the cycloaddition of CO2 to epoxides, to give cyclic carbonates, in the absence of any solvent. These results strongly suggest that the CSGO nanocomposite may open new vistas towards the development of ecofriendly material for catalytic conversion and adsorption of CO2 on industrial scale.

Multifunctional Photonics Nanoparticles for Crossing the Blood-Brain Barrier and Effecting Optically Trackable Brain Theranostics.

Theranostic photonic nanoparticles (TPNs) that cross the blood-brain barrier (BBB) and efficiently deliver a therapeutic agent to treat brain diseases, simultaneously providing optical tracking of drug delivery and release, are introduced. These TPNs are constructed by physical encapsulation of visible and/or near-infrared photonic molecules, in an ultrasmall micellar structure (<15 nm). Phytochemical curcumin is employed as a therapeutic as well as visible-emitting photonic component. In vitro BBB model studies and animal imaging, as well as ex vivo examination, reveal that these TPNs are capable of transmigration across the BBB and subsequent accumulation near the orthotopic xenograft of glioblastoma multiforme (GBM) that is the most common and aggressive brain tumor whose vasculature retains permeability-resistant properties. The intracranial delivery and release of curcumin can be visualized by imaging fluorescence produced by energy transfer from curcumin as the donor to the near-infrared emitting dye, coloaded in TPN, where curcumin induced apoptosis of glioma cells. At an extremely low dose of TPN, a significant therapeutic outcome against GBM is demonstrated noninvasively by bioluminescence monitoring of time-lapse proliferation of luciferase-expressing U-87 MG human GBM in the brain. This approach of TPN can be generally applied to a broad range of brain diseases.

Chitosan modified multi-walled carbon nanotubes and arginine aerogel for enhanced carbon capture.

Global warming is emerging as a significant issue because of increasing CO2 levels in the atmosphere due to urbanization, industrialization, and fossil-fuel usage. Therefore, reducing atmospheric CO2 levels using new materials with high carbon capture capacity and efficient CO2 capture technologies is essential. Herein, we propose a hybrid chitosan (CS) aerogel containing multi-walled carbon nanotubes (MWCNTs) and an arginine (Arg) aerogel (CSCNTArg aerogel) for efficient carbon capture. This aerogel was successfully synthesized using a cross-linker reagent via step-freeze drying method. Fourier-transform infrared spectroscopy and X-ray diffraction analyses confirmed the successful grafting of CS, MWCNTs, and Arg onto the CSCNTArg aerogel. The thermogravimetric analysis (TGA) confirmed good thermal stability up to 500 °C of the as-developed aerogel. Field-emission scanning electron microscopy showed that the surface morphology of the CSCNTArg aerogel differed from that of CS, Arg, and MWCNTs with pores on their surfaces. N2 and CO2 adsorption-desorption studies on the CSCNTArg aerogel were performed using the Brunauer-Emmett-Teller method and TGA, respectively. The CSCNTArg aerogel showed a high adsorption capacity of approximately 5.00 mmol g-1 at 35 °C. Therefore, this new material may be useful for facilitating high-efficiency CO2 adsorption to reduce atmospheric carbon footprint.

Synthesis of chitosan-based perylene dye material for photovoltaic solar-cell application.

Renewable energy, such as solar energy, is infinite, readily available, and has extensive applications. Dye-sensitized solar cells (DSSCs) have been well developed; thus, they can be developed with low production costs, high efficiency, and facile manufacturing techniques. This study proposes a novel chitosan biopolymer-based perylene dye; the dye is modified by chitosan with perylene-3,4,9,10-tetracarboxylic anhydride using a one-pot acylation of nitrogen nucleophiles for DSSCs. The chitosan biopolymer-based perylene dyes were characterized using attenuated total reflection infrared spectroscopy, solid-state 13C CP-TOSS nuclear magnetic resonance spectroscopy, X-ray powder diffraction analysis, thermogravimetric analysis, X-ray photoelectron spectrometry, and high-resolution field-emission scanning electron microscopy. The ultraviolet-visible and fluorescence spectroscopy of chitosan biopolymer-based perylene dye exhibited a red-shift compared with perylene-3,4,9,10-tetracarboxylic anhydride and chitosan. The DSSC properties of chitosan biopolymer-based perylene dye were investigated, and it exhibited a 2.022 % power-conversion efficiency. Thus, this promising chitosan biopolymer-based perylene dye may have potential applications in solar-cell technology.

Physiochemical, optical and biological activity of chitosan-chromone derivative for biomedical applications.

This paper describes the physiochemical, optical and biological activity of chitosan-chromone derivative. The chitosan-chromone derivative gels were prepared by reacting chitosan with chromone-3-carbaldehyde, followed by solvent exchange, filtration and drying by evaporation. The identity of Schiff base was confirmed by UV-Vis absorption spectroscopy and Fourier-transform infrared (FTIR) spectroscopy. The chitosan-chromone derivative was evaluated by X-ray diffraction (XRD), thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), scanning electron microscopy (SEM), photoluminescence (PL) and circular dichroism (CD). The CD spectrum showed the chitosan-chromone derivative had a secondary helical structure. Microbiological screening results demonstrated the chitosan-chromone derivative had antimicrobial activity against Escherichia coli bacteria. The chitosan-chromone derivative did not have any adverse effect on the cellular proliferation of mouse embryonic fibroblasts (MEF) and did not lead to cellular toxicity in MEFs. These results suggest that the chitosan-chromone derivative gels may open a new perspective in biomedical applications.

Synthesis, characterization and application of chitosan-N-(4-hydroxyphenyl)-methacrylamide derivative as a drug and gene carrier.

The aim of this study was to develop a green method to fabricate a novel CS modified N-(4-hydroxyphenyl)- methacrylamide conjugate (CSNHMA) and to evaluate its biomedical potential. CSNHMA has been prepared by a simple method via aza Michael addition reaction between CS and N- (4-hydroxyphenyl)-methacrylamide (NHMA) in ethanol. Its structural and morphological properties were characterized by various analysis techniques. The obtained results confirmed that a highly porous network structure of CSNHMA was successfully synthesized via aza Michael addition reaction. Consequently, it was analyzed as a drug and gene carrier. CSNHMA/pGL3 showed an enhanced buffering capacity due to the presence of NHMA moiety leading to higher transfection efficiency in all cancer cells (A549, HeLa and HepG2) as compared to native CS and Lipofectamine®. Therefore, these findings clearly support the possibility of using CSNHMA as a good transfection agent. For in vitro drug release study, we prepared CSNHMA nanoparticles (NPs) and curcumin loaded CSNHMA NPs of size <230 nm respectively via the non-toxic ionic gelation route and the encapsulation efficiency of drug was found to be 77.03%. In vitro drug release studies demonstrated a faster and sustained release of curcumin loaded CSNHMA NPs at pH 5.0 compared to physiological pH.

Synthesis of 2,5-furandicarboxylic acid-enriched-chitosan for anti-inflammatory and metal ion uptake.

The main aim of the present study is to synthesize a hitherto unreported polymer of chitosan (CS) and 2,5-furandicarboxylic acid (FDCA) derived from renewable biomass resources. For this purpose, CS was chosen which had -NH2 groups as abundant active sites. Synthesis of 2,5-furandicarboxylic acid-enriched-chitosan polymer (CS-FDCA) was carried out by reaction involving EDC-NHS coupling reagents. The structure of CS-FDCA polymer was confirmed by various characterization techniques such as Fourier-transform infrared spectroscopy (FTIR), proton nuclear magnetic resonance (1H NMR), X-ray powder diffraction (XRD), high resolution-field emission scanning electron microscope (HR-FESEM), and thermogravimetric analysis (TGA). Moreover, CS and CS-FDCA were scrutinized to examine their efficacies towards ameliorate inflammation via detection of lipopolysaccharide (LPS) induced nitric oxide (NO) production. As compared to CS, CS-FDCA with low concentration (1.0 µM) exhibited the better efficacy to reduce the NO production. Furthermore, CS-FDCA polymer showed high as 12.6% of Cu2+ ion uptake while CS showed 9.2% of Cu2+ ion uptake. Overall, it can be inferred that CS-FDCA polymer is expected to be used for biomedical application and for the removal of metal contaminants from industrial wastewater.

Application of macroalgal biomass derived biochar and bioelectrochemical system with Shewanella for the adsorptive removal and biodegradation of toxic azo dye.

The present study aimed towards adsorptive removal of the toxic azo dye onto biochar derived from Eucheuma spinosum biomass. Characterization of the produced biochar was performed using X-ray diffraction (XRD), scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), Fourier transform infrared spectroscopy (FTIR), and Brunauer-Emmett-Teller (BET). Eucheuma spinosum biochar (ES-BC) produced at 600 °C revealed a maximum adsorption capacity of 331.97 mg/g towards reactive red 120 dye. The adsorption data fitted best to the pseudo-second order kinetics (R2 > 0.99) and Langmuir isotherm (R2 > 0.98) models. These adsorption models signified the chemisorption mechanism with monolayer coverage of the adsorbent surface with dye molecules. Furthermore, the adsorption process was mainly governed by electrostatic interaction, ion exchange, metal complexation, and hydrogen bonding as supported by the solution pH, FTIR, XPS, and XRD investigation. Nevertheless, alone adsorption technology could not offer a complete solution for eliminating the noxious dyes. Therefore, the bioelectrochemical system (BES) equipped with previously isolated marine Shewanella marisflavi BBL25 was intended for the complete remediation of azo dye. The BES II demonstrated highest dye decolorization (97.06%) within 48 h at biocathode where the reductive cleavage of the azo bond occurred. Cyclic voltammetry (CV) studies of the BES revealed perfect redox reactions taking place where the redox mediators shuttled the electrons to the dye molecule to accelerate the dye decolorization. Besides, the GC-MS analysis revealed biotransformation of the dye into less toxic metabolites as tested using a phyto and cytogenotoxicity.

Chitosan-based zeolite-Y and ZSM-5 porous biocomposites for H2 and CO2 storage.

Sustainable energy is the most valuable clean and renewable energy for the future. A simple, robust, and inexpensive ecofriendly method has been developed here to prepare chitosan-based zeolite porous biocomposites via solvent exchange followed by calcination. The resulting chitosan-based zeolite biocomposites were characterized using advanced technologies including attenuated total reflection-infrared (ATR-IR) spectroscopy, X-ray powder diffraction (XRD) analysis, thermogravimetric analysis (TGA), high-resolution field-emission scanning electron microscopy (HR-FE-SEM), high-resolution transmission electron microscopy (HR-TEM), and nitrogen adsorption-desorption isotherms. The Brunauer-Emmett-Teller (BET) surface area of the ZeY@CS composite (795 m2 g-1) was greater than those of ZSM-5@CS (444 m2 g-1), pure chitosan, pure zeolite Y, and ZSM-5. The chitosan-based zeolite biocomposites show enhanced gas storage for small molecule like CO2 and hydrogen. Therefore, chitosan-based zeolite biocomposites should be suitable for energy storage, carbon capture, and sequestration (CCS) applications.

A systematic study on chitosan-liposome based systems for biomedical applications.

The advent of liposome technology with its unique features has led researchers to work relentlessly on the successful development of novel drug delivery vehicles based on liposomes. But still there are some limitations of using liposomes for biomedical applications because of their poor stability that is primarily the cause of rapid leakage of drugs incorporated within the said matrices. Therefore, a considerable interest has been paid on modification of surface of liposomes by combining it with several compounds of interest. Although chitosan-liposome based systems are not yet well-documented. Hence, in this review, we exclusively focused on the discussion about the preparation of various chitosan-liposome based systems and their suitable biomedical applications as well.

Synthesis and Application of N-methylphthalimidylazo Disperse Dyes to Cellulose Diacetate for High Wash Fastness.

Cellulose diacetate fibers were prepared from cellulosic biomass with high α-cellulose contents such as purified cotton linters and wood pulps. Cellulose diacetate fibers are sensitive to alkaline solution, which causes hydrolysis of the acetate ester to hydroxyl groups, especially at high temperatures. Thus, the low alkali-resistance of cellulose acetate fibers makes it difficult to achieve high wash fastness by restricting the application of intense after-treatment, such as reduction clearing. A series of N-methylphthalimide-based high-washable azo disperse dyes were synthesized and their dyeing and fastness properties on cellulose diacetate fabrics were investigated. From the overall results obtained in this study, N-methylphthalimidylazo disperse dyes are expected to be a desirable alternative to high value-added dyes that can be used for high color fastness dyeing of cellulose diacetate with a minimal discharge of wastewater during washing process.

Bio-based (chitosan/PVA/ZnO) nanocomposites film: Thermally stable and photoluminescence material for removal of organic dye.

Preparation of hitherto unreported chitosan/poly(vinyl alcohol)/ZnO nanocomposites film (designated as CS/PVA/ZnO) as an efficient bio-based nanocomposites is carried out by a greener approach involving mixing, solution casting and solvent evaporation. Synthesized chitosan-based nanocomposites films are characterized by various analytical techniques such as Fourier-transform infrared (FT-IR) spectroscopy, X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), thermogravimetric analysis (TGA), and differential scanning calorimetry (DSC). The photoluminescent properties of CS/PVA/ZnO films are thoroughly studied and compared with CS/PVA. The outcome suggested that the addition of ZnO nanoparticles increased the intensities and red shifting with respect to CS/PVA. The toxicity of chitosan-based nanocomposites films was examined by MTT assay using the NIH3T3 cells. The viability of chitosan-based nanocomposites films was found to be better than native chitosan and PVA films. Furthermore, the adsorption property of prepared chitosan-based nanocomposites films was tested for the removal of AB 1 dye.

Methyl methacrylate modified chitosan: Synthesis, characterization and application in drug and gene delivery.

A methyl methacrylate (MMA) modified chitosan (CS) conjugate (CSMMA) has been synthesized by a green method via Michael addition reaction between CS and MMA in ethanol. The synthesized conjugate was characterized by FT-IR, 1H NMR, X-ray diffraction spectrometry and SEM analysis. The results confirmed that CS was covalently linked to MMA yielding a highly porous framework. The uses of CSMMA were analyzed as a potential gene and drug delivery agent. CSMMA proved to be a reasonably good gene delivery agent based on transfection efficiency studies in mammalian cancer cell lines (A549, HeLa and HepG2). For drug delivery studies, nanoparticles of the CSMMA biopolymer were prepared by ionic gelation method with sodium tripolyphosphate (TPP). The prepared nanoparticles were characterized in terms of FE-SEM, DLS and zeta potential. In vitro drug release study of curcumin loaded CSMMA nanoparticles showed its maximal entrapment efficiency up to 68% and the drug release was more rapid at a pH (5.0) lower than physiological pH.

Dyeing of Polyester with 4-Fluorosulfonylphenylazo-5-pyrazolone Disperse Dyes and Application of Environment-Friendly Aftertreatment for Their High Color Fastness.

Dyeing and fastness properties of a series of 4-fluorosulfonylphenylazo-5-pyrazolone dyes on polyester were investigated in this study. The 4-nitrophenylazo-5-pyrazolone dyes were also synthesized to compare their dyeing and fastness properties on polyester with those of fluorosulfonyl-substituted analogues. The substantivity of 4-arylazo-5-pyrazolone derivatives containing a p-fluorosulfonyl group in the diazo component was lower than that of their nitro analogues which have a higher extinction coefficient and higher affinity because of the polar nitro group. They showed relatively hypsochromic color and lower chroma on polyester compared with their nitro analogues because of the relatively weaker electron-accepting power of the fluorosulfonyl group compared to the nitro group. Disperse dyeing of polyester with 4-fluorosulfonylphenylazo-5-pyrazolone disperse dyes achieved high color fastness and reduces the adverse environmental impact of the dyeing process by providing the option of performing alkali clearing instead of reductive clearing, which has high biological oxygen demand when discharged into the dyeing effluent and generates carcinogenic aromatic amines.

Mesoporous zeolite-chitosan composite for enhanced capture and catalytic activity in chemical fixation of CO2.

Carbon dioxide is one of the greenhouse gases whose increasing concentration in the atmosphere can cause severe problems to both human health and wildlife. A simple ecofriendly procedure was developed to prepare zeolite-chitosan (ZY-CS) composite using solvent exchange followed by calcination for adsorption and chemical fixation of CO2. The as synthesized ZY-CS composite along with zeolite and chitosan were characterized by attenuated total reflection infrared, X-ray diffraction, thermogravimetric, scanning electron microscopy, high-resolution transmission electron microscopy and nitrogen adsorption-desorption isotherms studies. The ZY-CS composite showed enhanced CO2 adsorption capacity compared with pure zeolite and chitosan. The composites also exhibited significant catalytic activity in the chemical fixation of CO2 into cyclic carbonates. This work is foreshadowing the prospect of ZY-CS composite in enhanced capture and catalytic activity in chemical fixation of CO2 for environmental applications.

Biolighted Nanotorch Capable of Systemic Self-Delivery and Diagnostic Imaging.

Sensitive imaging of inflammation with a background-free chemiluminescence (CL) signal has great potential as a clinically relevant way of early diagnosis for various inflammatory diseases. However, to date, its feasibility has been limitedly demonstrated in vivo with locally induced inflammation models by in situ injection of CL probes. To enable systemic disease targeting and imaging by intravenous administration of CL probes, hurdles need to be overcome such as weak CL emission, short glowing duration, or inability of long blood circulation. Here, we report a CL nanoprobe (BioNT) that surmounted such limitations to perform precise identification of inflammation by systemic self-delivery to the pathological tissues. This BioNT probe was engineered by physical nanointegration of multiple kinds of functional molecules into the ultrafine nanoreactor structure (∼15 nm in size) that combines solid-state fluorescence-induced enhanced peroxalate CL and built-in machinery to control the intraparticle kinetics of CL reaction. Upon intravenous injection into a normal mouse, BioNT showed facile blood circulation and generated a self-lighted strong CL torchlight throughout the whole body owing to the tiny colloidal structure with an antifouling surface as well as high CL sensitivity toward endogenous biological hydrogen peroxide (H2O2). In mouse models of local and systemic inflammations, blood-injected BioNT visualized precise locations of inflamed tissues with dual selectivity (selective probe accumulation and selective CL reaction with H2O2 overproduced by inflammation). Even a tumor model that demands a long blood circulation time for targeting (>3 h) could be accurately identified by persistent signaling from the kinetics-tailored BioNT with a 65-fold slowed CL decay rate. We also show that BioNT exhibits no apparent toxicity, thus holding potential for high-contrast diagnostic imaging.

Amphiphilized poly(ethyleneimine) nanoparticles: a versatile multi-cargo carrier with enhanced tumor-homing efficiency and biocompatibility.

Current theranostic approaches in cancer therapy demand delivery systems that can carry multiple drugs or imaging agents in a single nanoplatform with uniform biodistribution and improved target specificity. In this study, we have developed amphiphilized poly(ethyleneimine) nanoparticles (aPEI NPs) as a versatile multi-cargo delivery platform. The aPEI NPs were engineered to have the loading capacity for both hydrophobic molecules and negatively charged hydrophilic colloidal cargos through amphiphilic modification, i.e., octadecylation and subsequent PEGylation of poly(ethyleneimine). In the aqueous phase, the resulting aPEIs underwent amphiphilic self-assembly into spherical nanoparticles whose structure is constituted of the hydrophobic core with the positively charged surface and the hydrophilic neutral corona. The high degree of PEGylation resulted in the tiny colloidal size (<15 nm in diameter) and rendered the outmost surface coated with an antifouling corona which minimizes general shortcomings of poly(ethyleneimine)-based nanocarriers (e.g., cytotoxicity and liver filtration) while keeping its advantage (loading capability for negatively charged drugs). The unique nanostructure of aPEI NPs allowed for facile loading of hydrophobic model drugs (rubrene and IR780) in the core as well as negatively charged colloids (Pdots, proteins and DNA) on the inner surface via the hydrophobic and electrostatic interactions, respectively. Fluorescence imaging experiments demonstrated that the highly PEGylated aPEI-25 NPs showed prolonged blood circulation with minimal liver filtration and efficient delivery of the loaded cargos to the tumor. These combined merits, along with negligible toxicity profiles both in vitro and in vivo, validate the potential of aPEI-25 NPs as versatile nanocarriers for multi-cargo delivery.

Physiochemical and optical properties of chitosan based graphene oxide bionanocomposite.

In the present investigation an ecofriendly approach and a simple homogeneous solution casting method led to the development of biodegradable chitosan/graphene oxide bionanocomposites. The formation of bionanocomposite was confirmed by UV-vis, FT-IR, Raman spectroscopy, XRD, and further evaluated by thermogravimetric analysis (TGA), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The circular dichroism (CD) study of chitosan/graphene oxide revealed that the intensity of the negative transition band at wavelength of 200-222 nm decreased with the different pH of chitosan/graphene oxide solutions. It was also found that the pH conditions affect the interaction between chitosan and graphene oxide. Optical properties of chitosan/graphene oxide are evaluated by photoluminescence (PL) spectroscopy which showed blue shift at excitation wavelength of 255 nm compared to graphene oxide. These results strongly suggest that the bionanocomposite materials may open new vistas in biotechnological, biosensor and biomedical applications.

Synthesis, physiochemical and optical properties of chitosan based dye containing naphthalimide group.

A new biopolymer dye containing naphthalimide moiety was synthesized by reaction of N-naphthaloyl chitosan with 1-ethyl-6-fluoro-1,4-dihydro-4-oxo-7-piperazino-3-quinolinecarboxylic acid. N-naphthaloyl chitosan was synthesized by reaction of chitosan with 4-bromo-1,8-naphthalic anhydride in aqueous media by greener approach. The degree of substitution of chitosan biopolymer dye is 0.55 with a yield of 70%. The synthesized materials were characterized by using UV-vis, (1)H NMR, FTIR, and FT-Raman spectroscopy. Some physical properties and surface morphology were characterized by X-ray diffraction (XRD), thermogravimetric analysis (TGA), differential scanning calorimetry (DSC) and scanning electron microscopy (SEM). Optical properties of chitosan biopolymer dye were evaluated by photoluminescence (PL) spectroscopy that showed red shift (λ(em)) peak at 442 nm and 551 nm at excitation wavelength 325 nm in comparison to chitosan. The solubility of chitosan biopolymer dye increased in most of the organic solvents. These results may provide new perspectives in biomedical applications as an optical and sensitive biosensor material.