Schiff Base Research Articles

Synthesis of novel bi-Zwitterion Schiff base derivate from 4‑hydroxy-2H-pyran-2-one: DFT/HSA-interactions, thermal, physicochemical, TD-DFT and optical activity

A novel tetradentate bi-Zwitterion Schiff base (SB): 3,3′-((1E,1′E)((oxybis(4,1-phenylene))-bis-(azanylylidene))-bis(ethan-1-yl-1-ylidene))bis(4‑hydroxy-2H-pyran-2-one) was synthesized, via reflux condensation of 3-acetyl-4‑hydroxy-6-methyl-2H-pyran-2-one with 4,4′-oxydianiline in methanol. The SB ligand was characterized using various physicochemical techniques, including 1HNMR , elemental analysis (CHN-EA), XRD, MS, UV–vis, and FT-IR. The XRD analysis confirmed the presence of a bi-zwitterionic salt form, characterized by intra-H-bond interactions between [N+—H…−O] groups. Hirschfield surface analysis (HSA) and MEP/MAC/NPA were conducted to gain insight into the intra/intermolecular hydrogen bond interactions of the molecule. The completion of the SB dehydration reaction was UV–vis., tracked by studying the behavior of the reactants before and after mixing. Additionally, the absorbance/transmittance, TD-DFT, and optical properties of the SB were evaluated. Finally, the TG/DTG analysis was used to determine the thermal stability of the desired SB ligand.

Coumarin Schiff base derivatives with 4′-alkoxy biphenyl-4-carboxaldehyde: Synthesis, mesomorphic studies and DFT calculations

Two homologous series of coumarin Schiff base derivatives with 4′-alkoxy biphenyl-4-carboxaldehyde have been designed and synthesized. All the compounds were analyzed IR, 1H NMR, 13C NMR, ESI-MS and CHN analysis followed by mesomorphic properties polarizing optical microscopy (POM) and differential scanning calorimetry (DSC) analysis. In the first homologous series BPS(6–16), Schiff base of 7-alkoxy-3-aminocoumarin with 4′-alkoxy biphenyl-4-carboxaldehyde, alkoxy chain length was varied systematically at both end of the molecules such as n = 6,8,10,12,14,16. In this series, BPS(6–10) (n = 6,8,10) exhibited enantiotropic nematic(N) and smectic C (SmC) mesophase and turned to monophasic on increasing the chain length n = 12,14,16 in BPS(12–16) with stable SmC mesophase. While in the second homologous series 10BPU(2–16), systemic variation of alkoxy chain length was carried out at coumarin end only (n = 2–18) and 4′-decyloxy-biphenyl-4-carboxaldehyde was used for Schiff base formation. In the this series, early member of the series with n = 2,3 showed enantiotropic very stable (∼ 145 °C) nematic mesophase, while N as well as SmC mesophase were observed for n = 4–8 at, whereas with increase of chain length stability of nematic mesophase was decreased and that of SmC was increased. Higher membered analogous 10BPU(12–16) exhibited SmC mesophase with stability in the rage of 130–160 °C. VT-XRD analysis was also confirmed the tilted SmC mesophase in this class of compounds. For both the series, all compounds were studied for the DFT calculations as well as literature molecules with similar variations. Based on the calculated structural (length, aspect ratio) and electronic (dipole moment, polarizability) parameters were correlated with mesomorphic behaviour observed for literature compounds and compounds from both the series followed by the detailed discussion.

Synthesis, characterization, thermal, theoretical studies, antimicrobial, antioxidant activity, superoxide dismutase-like activity and catalase mimetics of metal(II) complexes derived from sugar and Schiff base

Abstract Scientists are searching for reactive oxygen species, which have been associated with various health issues like heart problems, neurological disorders, inflammation, and aging. Salen complexes have proven to be effective in multiple oxidative stress situations and have been used as catalase and superoxide mimetics. To explore this further, three mixed complexes were synthesized using a Schiff base (salen) and a sugar (d-glucose) with Co(II), Ni(II), and Cu(II) ions. These complexes were then diagnosed by different analytical and spectral techniques. Stoichiometry, stereochemistry, some physical properties, and the method of bonding complexes were measured. Comparisons of the IR and 1HNMR spectra of the ligands with the complexes demonstrated the involvement of the azomethine group of the ligand in the chelation process. The mass spectra and TGA agree with the proposed formula of the complexes, and the conductivity and UV–Vis data supported the octahedral geometry of the complexes, and information was obtained from partial parameter calculations by molecular modeling. The metal complexes exhibited strong antimicrobial and antioxidant properties when compared to standard drugs. The like-superoxide and catalyst mimetic complexes were screened using DPPH ABTS, revealing their effectiveness.

Synthesis and characterization of α-(4-(2,3-hydroxylpropoxy)phenylimino)-o-cresol Schiff base as an effective UV-absorber for ink systems

Schiff base is a diverse group of organic compounds and has potential as a UV absorber for ink systems due to its high UV protection, simple synthesis, and high dispersion in organic matrices. In this work, a novel Schiff base α-(4-(2,3-dihydroxylpropoxy)phenylimino)-o-cresol (named GMA-I) was synthesized and investigated as a UV absorber for ink system. The UV-protection of GMA-I was evaluated on ink-coated duplex substrate samples via color measurement using an accelerated UV test chamber. The results showed that the GMA-I exhibited strong absorption in both UVA and UVB regions with an extra high molar absorption coefficient of 43,554 M−1 cm−1, and high thermal stability of 271.4 °C. Interestingly, the GMA-I showed high UV protection for ink platform at low content of 2 wt% thank to the intramolecular proton transfer mechanism and therefore potential as a UV absorber additive for ink systems.

A specific, ultra-sensitive and rapid naked-eye on-site recognition of CN– and Cu2+ ions in tap water using an isonicotinohydrazide-salisaldehyde hybrid probe

Schiff base 1, namely (E)-N'-(2-hydroxy-3-methoxybenzylidene)isonicotinohydrazide, exhibits amide-iminol tautomerism in its molecular structure and functions as a colorimetric sensor for detecting cyanide (CN–) and copper ions (Cu2+) in ethanol/H2O (1:1). Compound 1 can distinguish CN– and Cu2+ ions from various competing ions based on unique color and spectral alterations. Spectral analyses reveal the prevalence of the iminol-form of 1 over the amide-form, enabling the selective detection of CN– and Cu2+ ions. When CN– is present, deprotonation occurs in both the phenolic and iminolic groups, leading to increased conjugation along molecule 1, as confirmed by 1H NMR spectroscopy. On the other hand, Cu2+ sensing involves coordination with 1 through a tridentate moiety, specifically interacting with the azomethine nitrogen atom as well as the deprotonated phenolic and iminolic groups. This mechanism allows for superior detection of Cu2+ compared to CN–. Key features of this sensor include its selectivity, sensitivity (with detection limits of 4.05 nM for CN– and 1.7 nM for Cu2+), a rapid response (less than 5 s), and the capability for on-site monitoring of CN– and Cu2+ ions in tap water using either solution or solid kits. Additionally, DFT calculations have validated the influence of Cu2+ and CN– on the system's electronic structure, as demonstrated by the results of MEP maps and changes in gap energy values.

Square-planar nickel/copper(II) complexes of (E)-2-(((2-ethylphenyl)imino) (phenyl) methyl)phenol: Supramolecular analysis, keto-enol tautomerism, polymorphism and antibacterial activities

A new Schiff base proligand, (E)-2-(((2-ethylphenyl)imino)(phenyl)methyl)phenol (HL), was synthesized from 2-hydroxybenzophenone and 2-ethylaniline and its coordination chemistry with nickel(II) and copper(II) acetate explored. In solution, the proligand HL undergoes ketoimine -enolimine tautomerism which settles exclusively into an enolimine form in the solid-state. Interestingly, while a single crystalline habit was obtained for the nickel complex 1 (block-shaped single crystals), the copper species 2 was found to solidify in two detectable polymorphs: block-shaped crystals (2a, monoclinic space group P21/c) and rhombic crystals (2b, triclinic space group P-1). Single-crystal X-ray diffraction studies reveal that the N,O Schiff base ligand chelates the divalent metal ions with square-planar geometry in the isostructural 1 and 2a and in a distorted square-planar geometry with a dihedral chelate-plane angle of 27.9° in 2b. The copper complex 2 exhibits significant antibacterial activity against the E. coli and medium activity against S. aureus bacteria. The physical properties of the complexes were further probed using thermal techniques, while their electronic structure was investigated by electrochemistry and electronic absorption spectroscopy.

Novel Schiff base embedded in nanostructured molecularly imprinted polymers as OFF–ON fluorescent sensor for highly selective detection of rutin residues in fruit juice

This study aimed to create a fluorescent novel Schiff base polymer (SBP) sensor for the detection of rutin (RT) flavonoid based on nanostructured molecularly imprinted polymer (SBM), precisely designed template molecules, and site-specific post-imprinting modifications. The fabricated SBM sensor was characterized in detail, and the prepared SBM exhibited stable and sensitive reproducible fluorescence response and highly selective recognition capability for detecting trace amounts of RT. Besides, the influential factors, such as pH and incubation time were performed in the optimal extraction conditions. The calibration curve yields a linear range for the detection of RT under optimal conditions. The linear fluorescence response of SBM to RT was obtained in the concentration range of 1-200μgL− 1 (R2 = 0.9988) with a limit of detection (LOD) of 0.024μgL-1. The SBM presented satisfying recoveries with a relative standard deviation of less than 3.0% (n = 7) in spiked samples. The sensor shows broad prospects in the quality evaluation and grading of functional foods, as it can rapidly identify and quantify RT in red raspberry and green tea samples.

Antiferromagnetic resorcinol bridged dinuclear square-planar copper (II) complexes: Syntheses, structural, spectroscopic and magnetic properties

A new C2-symmetric Schiff base ligand (H2L) featuring a core resorcinol bridging unit has been created, utilizing the Duff formylation reaction followed by the Schiff base condensation reaction. The ligand was characterized by various spectroscopic techniques.. Cu(II) salts with varying coordinating anions (Cl− and SCN−) in methanol were allowed to react with this ligand in a 2:1 M ratio to create dinuclear Cu(II) complexes. The complexes were isolated in pure form and characterized by, elemental analysis,single crystal X-ray crystallography and various spectroscopic techniques. X-ray analysis discloses that both complexes are dinuclear, where the ligand (H2L) being tridentate in nature, coordinates to Cu(II) through its two N donor atoms and one O donor atom in the equatorial positions. The respective anions (−Cl− for 1 and –SCN− for 2) coordinate to Cu(II) to complete its square planar geometry. Temperature dependent magnetic susceptibility measurements indicate weak antiferromagnetic exchange interactions with a coupling constant of J = −5.9(1) cm−1 and g = 2.148(1) for 1 and J = −10.08(1) cm−1 and g = 2.106(1) for 2.

Unveiling the Therapeutic Potential of Organotellurium(IV) Schiff Base Complexes through Structural Elucidation, Antimalarial, Antioxidant and Antimicrobial Studies

Infectious diseases have long been a formidable adversary to human health and well-being, presenting a persistent global challenge with far-reaching implication for individuals, communities and societies at large. Thus, with the aim of a combating agent against malarial and oxidant causing ailments, the newly synthesized Organotellurium(IV) complexes with a hydroxynaphthaldehyde Schiff base ligand are proposed in the present research. The structures of the complexes were established through various physical and spectral analysis. The weak electrolytic (8.77 to 35.08 ohm−1 cm2 mol−1) and crystalline nature of the compounds were demonstrated by molar conductivity and TGA, respectively. The ligand and complexes (7a-7f) shows molecular ion peaks at m/z 458.3563, 726.1039, 713.6978, 727.6179, 799.4780, 771.3178 and 799.3978 amu which were well consistent with their formula, revealing formation of compounds. The shifting of ligand's azomethine peak (7.74 ppm) and disappearance of naphthyl hydroxyl proton (12.28 ppm) in 1H NMR spectra confirmed the chelation of ligand with metal ion in proposed manner. In the FT-IR spectra, the complexation of ligand with metal ion was confirmed by disappearance of hydroxyl group (3355 cm−1) band and shifting of C=N (1245 cm−1) and C-O (1632 cm−1) band whereas appearance of Te-O (of 285-293 cm−1) and Te-N (458-467 cm−1) bands, revealed the bonding of metal with metal and octahedral nature of the complexes. Optimized structures, HOMO-LUMO energies and associated chemical reactivity descriptors of the compounds were computed by DFT calculations. The in vitro studies demonstrate that the complexes 7c (1.06 ± 0.11 μM) and 7f (1.22 ± 0.05 μM) exhibited moderate inhibition of the Plasmodium falciparum 3D7 strain, complexes 7a (100.96 ± 0.32 μg/mL) and 7d (96.32 ± 0.40 μg/mL) demonstrated the highest free radical quenching ability. Complex 7c displayed the highest antibacterial actions, whereas 7f exhibited the highest antifungal actions against the tested pathogens. Molecular docking and ADMET studies demonstrated enhanced binding affinity of the complexes compared to the Schiff base and their drug-like qualities.

Reaction of Pyrrolobenzothiazines with Schiff Bases and Carbodiimides: Approach to Angular 6/5/5/5-Tetracyclic Spiroheterocycles.

1H-Pyrrole-2,3-diones, fused at [e]-side with a heterocycle, are suitable platforms for the synthesis of various angular polycyclic alkaloid-like spiroheterocycles. Recently discovered sulfur-containing [e]-fused 1H-pyrrole-2,3-diones (aroylpyrrolobenzothiazinetriones) tend to exhibit unusual reactivity. Based on these peculiar representatives of [e]-fused 1H-pyrrole-2,3-diones, we have developed an approach to an unprecedented 6/5/5/5-tetracyclic alkaloid-like spiroheterocyclic system of benzo[d]pyrrolo[3',4':2,3]pyrrolo[2,1-b]thiazole via their reaction with Schiff bases and carbodiimides. The experimental results have been supplemented with DFT computational studies. The synthesized alkaloid-like 6/5/5/5-tetracyclic compounds have been tested for their biotechnological potential as growth stimulants in the green algae Chlorella vulgaris.

Design and Synthesis of Simple Quinoline-based Organic Molecules as Dual/Multifunctional Chemosensors for the detection of Cu2+/Fe3+ ions

The current research deals with the sensitivity of a turn-on-off fluorescence chemosensor using the probe, namely (E)-2-(((2-hydroxy-5-methylphenyl) imino)methyl) quinolin-8-ol (HQ-AMP) as a selective detection of Cu2+/Fe3+ ions in DMSO: H2O (1:1, v/v). The probe HQ-AMP was synthesized using a simple acid catalyst, Schiff base condensation, which involves the reaction between aldehyde and amine. This probe shows a significant fluorescence response towards Cu2+ and Fe3+ ions among the other alkaline earth metal ions. The HQ-AMP forms a 1:1 stoichiometry complex with a high binding constant for Cu2+ and Fe3+ ions with a low detection limit of 34 nM and 47 nM, respectively. Due to their strong intermolecular charge transfer properties, the probe HQ-AMP shows intense fluorescence at 488 nm upon excitation at 350 nm. The selective fluorescence quenching of probe HQ-AMP with Cu2+/Fe3+ ions shows static/dynamic quenching and their quenching constant of 1.93 ×10−8 and 2.06 ×10−8, respectively. Also, the probe shows the highest selectivity towards Cu2+/Fe3+ ions over the other tested metal ions.

Preparation of amino cellulose aerogel and its formaldehyde adsorption properties

The aerogel prepared from cellulose has the advantages of low density, high porosity, large specific surface area, good gas diffusion and adsorption space, which is a good gas adsorption material. In this study, microcrystalline cellulose was used as raw material, and LiBr ionic liquid was used as a solvent system. In addition, cellulose aerogel was modified by polyethyleneimine, which retained three-dimensional network structure and had excellent formaldehyde adsorption capacity. The adsorption capacity of polyethyleneimine-modified cellulose aerogel (PCA) to formaldehyde can reach 12.3 mg/g at 25 ℃. It was found that the adsorption capacity of PCA aerogel for formaldehyde changed with the increase in nitrogen content. The adsorption of formaldehyde was mainly through the chemical adsorption of the Schiff base reaction between NH2 and formaldehyde molecules in polyethylenimine (PEI).

Schiff base derivative flame-retardant endowing epoxy resin with toughness, transparency, and high flame retardancy

In this study, a novel phosphorus-containing flame retardant, SMAE, was prepared through a nucleophilic addition of N,N'-bis(salicylidene)ethylenediamine (SAED) and phenyl hypophosphite. SMAE can dissolve well in epoxy resin and provides molecular-level flame retardancy. By using SMAE as a co-curing agent and DDM to cure epoxy resin, EP/SMAE composites with excellent flame retardancy and good mechanical properties were obtained. As the dosage gradually increases, the limited oxygen index (LOI) values continue to rise. At a 5 % dosage, the Limiting Oxygen Index (LOI) value can reach 39.7 % and meet the UL 94 V-0 standard. It is observed that SMAE mainly exerts a blowing-out effect in EP. In addition, the use of SMAE as a co-curing agent can improve the impact strength of EP. The impact strength of 5 % SMAE/EP can reach 14.15 kJ/m2, which is 25 % higher than that of pure EP.

Tuning the sensing properties of isophthalic dihydrazide-based receptor via formation of organic–inorganic hybrid and metal complex: An enhanced sensing activity for Hg2+ and CN− detection in semi-aqueous medium

A Schiff base receptor H2L has been synthesized through a condensation reaction between 2-hydroxy-3-methoxybenzaldehyde and isophthalic dihydrazide. The compound has been characterized by various characterization techniques such as 1H, FT-IR, CHNS and single crystal X-ray crystallography. Despite its limited solubility in water, a strategy was employed to enhance its effectiveness in aqueous environment by forming fluorescent nanoaggregates of H2L through a re-precipitation method. The fluorescent nanoaggregates of H2L show strong recognition ability towards Hg2+ ions through a fluorescence turn-on mechanism in H2O–DMSO (90 %, v/v). The study has been extended by developing a hybrid nano-assembly of H2L as Ag@H2L which exhibits higher sensitivity for Hg2+ ions with an improved detection limit 9.3 × 10−9 M as compared to that of organic nanoaggregates having 7.9 × 10−8 M in H2O–DMSO (90 %, v/v). Further Hg2+ complex of H2L has also been synthesized and characterized using elemental analysis, mass spectrometry and IR, UV–Vis spectroscopic techniques. The findings have been complimented by density functional theory (DFT) computations. The synthesized H2L-Hg complex is able to detect CN− ion using UV–Vis spectroscopy in H2O–DMSO (80 %, v/v) with a detection limits of 1.04 × 10−6 M.

Aminoquinoline-Based Ruthenium(II) and Iridium(III) Polypyridyl Complexes: Investigating Potential Photosensitisers for Cancer Treatment via Photodynamic Therapy

Cancer is a devastating noncommunicable disease that remains one of the most pressing health challenges of the twenty-first century. Chemotherapy stands as one of the most common and effective cancer treatment methods. However, severe side effects and acquired drug resistance in many cancers have significantly diminished the efficacy of current chemotherapeutic agents. The urgent demand for novel treatment modalities has led to the development of photodynamic therapy (PDT) for the treatment of various cancer types. In this work, the synthesis of aminoquinoline-based transition metal complexes containing two PGMs (Ir(III) and Ru(II)) as potential photosensitisers is described. Mononuclear N,N-chelated Ru(II) and Ir(III) transition metal complexes were synthesized by reacting 4-aminoquinoline Schiff base ligands, which contained either a pyridyl or a quinolyl entity. The photostable Ru(II) and Ir(III) polypyridyl complexes were investigated for their potential use as PDT agents. In vitro cytotoxicity screenings conducted against a melanoma cell line (501mel) both in the absence and presence of light confirmed that all complexes demonstrated increased biological activity when exposed to visible light at 455 nm. Overall, the complexes containing a quinoline substituent consistently demonstrated superior activity compared to those substituted with pyridine, underscoring the significance of the quinoline pharmacophore for anticancer drug design.

New nanometric metal complexes based on thiazole derivative as potential antitumor and antimicrobial agents: Full structural elucidation, docking simulation and biological activity studies

Novel Mn(II), Ni(II), Zr(IV) and Cd(II) nanosized complexes of thiazole Schiff base derivative (HL) were synthesized for further medicinal applications. The inspected complexes were fully characterized using elemental and thermal analyses in addition to infrared spectroscopy (IR) and nuclear magnetic resonance (1HNMR). Electronic absorption spectra, X-ray powder diffraction (XRD), transmittance electron microscopy (TEM), molar conductance and magnetic moment were also measured and explained. The brought about data revealed that the ligand–metal chelation happened through the N atom of N = N group, and the ortho-dehydrogenated phenolic O atom to form the chelates where the metal binds with one molecule of the parent ligand. All applied spectroscopic and analytical techniques confirmed tetrahedral geometry in Mn(II) and Ni(II) complexes and octahedral geometry for Cd(II) and Zr(IV) complexes. The ligand, Mn(II), Ni(II), and Zr(IV) chelates' XRD patterns indicated an amorphous character where the Cd(II) complex's nature is crystalline. Transmission electron microscopy (TEM) images of the prepared compounds showed that the surface morphology is uniform and homogeneous. Also, the metal ions distribute through the complexes' surface in a nanosized nature. The metal complexes have been simulated by docking in the co-crystal structures of the liver cancer and breast cancer proteins with PDB IDs, 2JW2 and 3S7S, successively. Antibacterial, antifungal and anticancer activities for the ligand that has been produced and its complexes were achieved. The most encouraging antitumor results were acquired by Ni(II) chelate which exhibited an IC50 of 23.52 µg/ml contra MCF-7 cells (human breast cancer) which is lower than the reference 5-Fluorouracil (5-FU, IC50 = 28.00 µg/ml).

Biodegradable chitin nanofiber-alginate dialdehyde hydrogel: An injectable, self-healing scaffold for anti-tumor drug delivery

Injectable hydrogels fabricated from natural polymers have attracted increasing attentions for their potential in biomedical application owing to the biocompatibility and biodegradability. A new class of natural polymer based self-healing hydrogel is constructed through dynamic covalent bonds. The injectable self-healing hydrogels are fabricated by introducing alginate aldehyde to form Schiff base bonds with the chitin nanofibers. These hydrogels demonstrate excellent self-healing properties, injectability, and pH-responsive sol-gel transition behaviors. As a result, they can serve as carriers to allow an effective encapsulation of doxorubicin (DOX) for drug delivery. Furthermore, these hydrogels exhibit excellent biocompatibility and degradability in vitro and in vivo. The sustained release of DOX from the hydrogels effectively suppresses tumor growth in animal models without causing significant systemic toxicity, suggesting their potential application in anti-tumor therapies.

Injectable bio-multifunctional hyaluronic acid-based hydrogels loaded with poly ADP-ribose polymerase inhibitors for ovarian cancer therapy

The recent use of PARP inhibitors (PARPi) in the maintenance treatment of ovarian tumor has significantly improved the survival rates of cancer patients. However, the current oral administration of PARP inhibitors fails to realize optimal therapeutic effects due to the low bioavailability in cancerous tissues, and often leads to a range of systemic adverse effects including hematologic toxicities, digestive system reactions, and neurotoxicities. Therefore, the demand for an advanced drug delivery system that can ensure effective drug administration while minimizing these unfavorable reactions is pressing. Injectable hydrogel emerges as a promising solution for local administration with the capability of sustainable drug release. In this study, we developed an injectable hydrogel made from aminated hyaluronic acid and aldehyde-functionalized pluronic127 via Schiff base reaction. This hydrogel exhibits excellent injectability with short gelation time and remarkable self-healing ability, and is applied to load niraparib. The drug-loaded hydrogel (HP@Nir hydrogel) releases drugs sustainably as tested in vitro as well as displays significant anti-proliferation and anti-migratory properties on human epithelial ovarian cancer cell line. Notably, HP@Nir hydrogel effectively suppresses the growth of ovarian cancer, without significant adverse reactions as demonstrated in animal studies. Additionally, the developed hydrogel is gradually degraded in vivo for around 20 d, while maintaining good biocompatibility. Overall, the injectable hydrogel loaded with niraparib provides a secure and efficient strategy for the treatment and management of ovarian cancer.

Organoruthenium metallocycle induced mutation in gld-1 tumor suppression gene in JK1466 strain and appreciable lifespan expansion

Four Ru(II) complexes (A2-A5) were synthesized from the reaction of coumarin Schiff base ligands (7da2-tsc, 7da3-mtsc, 7da4-etsc and 7da5-ptsc) with [RuHCl(CO)(PPh3)3]. The compounds were characterized by FT-IR, UV–Vis, 1H, 13C and 31P NMR, mass spectrometry and crystallographic analysis. Calf Thymus DNA (CT-DNA) binding studies revealed the intercalative mode of binding of the complexes with DNA. The results of Bovine serum albumin (BSA) binding studies established the interaction between BSA followed static quenching mechanism. The cytotoxic effects of the complexes and the ligands were evaluated against breast (MCF-7 and MDA-MB-231) and lung carcinoma cell lines (A549 and NCI-H460) using MTT assay. Complex A4 demonstrated potent cytotoxic effects on both breast and lung cancer cells. Furthermore, morphological observations and FACS analysis showed the decrease in cell density by complex A4 by induced morphological changes and apoptotic body formation and cell death in both breast and lung cancer cells. Moreover, the invertebrate model Caenorhabditis elegans was employed to assess the in vivo anticancer activity of compound A4. The findings indicated that the treatment with A4 reduced tumor development and significantly extended organismal lifespan by 64 % in the tumoral strain JK1466 without adversely affecting essential physiological functions of the worm. Additionally, A4 demonstrated an upregulation of two crucial antioxidant defense genes. Overall, these results suggested that the compound A4 can be a potential candidate with novel chemotherapeutic applications.

An injectable and retrievable bioartificial pancreas fabricated by time-sequentially assembling islets-laden microgels for minimally invasive treatment of type 1 diabetes

Islets transplantation is a promising method to treat type 1 diabetes. Unfortunately, current islet encapsulation and transplantation strategies are difficult to simultaneously achieve the minimally invasive transplantation, rapid mass transportation, accurate positioning, long-term stability and easy retrieval. Herein, we present a novel strategy for islet encapsulation and transplantation that integrates the advantages of microencapsulation and macroencapsulation. Specifically, islets are first encapsulated in methacrylated carboxymethyl chitosan (CMCSMA) microgels by droplet microfluidic technology, and then oxidized sodium alginate-succinimide ester (OSA-NHS) as the assembling agent is added to time-sequentially assemble the islets-laden microgels. The as-formed microgel assembly (MA-CHO/NHS), or namely bioartificial pancreas, is injectable before transplantation due to the quick formation of dynamic Schiff base bonds, and becomes quite stable after transplantation with the slow formation of stable amide bonds.In addition, the interconnected micropores inside the microgel assembly is beneficial for mass transportation, and the abundant aldehyde and succinimide ester groups on assembling agent ensures good tissue adhesion. This injectable, tissue-adhesive, microporous, positionable and retrievable bioartificial pancreas can reverse the blood glucose levels of diabetic mice from hyperglycemia to normoglycemia for at least 90 days, and thus shows a broad application prospect in the field of diabetes treatment.