Fatima Javed

Classification, processing and application of hydrogels: A review.

This article aims to review the literature concerning the choice of selectivity for hydrogels based on classification, application and processing. Super porous hydrogels (SPHs) and superabsorbent polymers (SAPs) represent an innovative category of recent generation highlighted as an ideal mould system for the study of solution-dependent phenomena. Hydrogels, also termed as smart and/or hungry networks, are currently subject of considerable scientific research due to their potential in hi-tech applications in the biomedical, pharmaceutical, biotechnology, bioseparation, biosensor, agriculture, oil recovery and cosmetics fields. Smart hydrogels display a significant physiochemical change in response to small changes in the surroundings. However, such changes are reversible; therefore, the hydrogels are capable of returning to its initial state after a reaction as soon as the trigger is removed.

New supramolecular ferrocenyl amides: synthesis, characterization, and preliminary DNA-binding studies

Three ferrocenyl amides have been synthesized and characterized by analytical techniques. Based on single-crystal X-ray analysis, a supramolecular structure was attributed to 1 owing to the presence of intermolecular non-covalent interactions. UV-Visible spectroscopy, viscometry, and dynamic laser light scattering was used to assess the mode of interaction and binding of these complexes with DNA, which varied in the sequence 1 > 2 > 3. The binding is presumably due to the ability of these complexes to form secondary non-covalent interactions with DNA bases. Complex-DNA adduct formation depends on the nature of R of the amide.

Synthesis, characterization, semi-empirical study, and biological activities of organotin(IV) and transition metal complexes with o-methyl carbonodithioate

Three transition metal and six organotin(IV) complexes have been synthesized by treating potassium o-methyl carbonodithioate with ZnCl2/CdCl2/HgCl2 and R2SnCl2/R3SnCl under stirring. The complexes were characterized by IR, 1H, and 13C NMR spectroscopies. IR results show that the ligand is bidentate in 1–3 while monodentate in 4–9, which is also confirmed by semi-empirical study. NMR data reveal four-coordinate geometry in solution. HOMO–LUMO study shows that 7 and 9 are thermodynamically unstable. The enzyme inhibition study shows that 1 is a potent inhibitor of ALP, EC 3.1.3.1, resulting in very slow rate of formation and breakdown of enzyme–substrate complex. UV/visible spectroscopy was used to assess the mode of interaction and binding of the complexes with DNA which shows that 9 exhibits higher binding constant when compared to 6. In protein kinase inhibition assay, 1 was active, while antifungal activity shows that organotin(IV) complexes are more active than transition metal complexes. Graphical Abstract

Synthesis, Structural Characterization, Theoretical Calculations and In Vitro Biological Activities of Organotin(IV) Complexes with [O,O] Donor Ligand

The present study deals with the synthesis of ligand 4-oxo-4-(thiazol-2-ylamino)butanoic acid and afterward its organotin(IV) carboxylates [Bu3SnL] (1), [Ph3SnL] (2), [Me2SnL2] (3), [Bu2SnL2] (4) and [Ph2SnL2] (5). These complexes were characterized by useful techniques like elemental analysis, FT-IR, NMR (1H, 13C) and single crystal analysis. The ligand coordinates to tin atom via the carboxylate group. Complex 1 has also been studied by single crystal XRD analysis. It showed that tin has distorted tetrahedral geometry due to bulky butyl groups that hinder the carbonyl oxygen of the ligand interaction with the adjacent tin atom for further coordination. The HOMO–LUMO study of ligand “HL” and its tin complexes 3 and 5 indicated that tin complexes are thermodynamically more stable than the ligand. The synthesized complexes were screened for their biological activities like antibacterial, antifungal, antileishminial, cytotoxicity and protein kinase inhibition studies in vitro. Complexes 1 and 2 exhibited maximum antileishmanial activity that was even higher than that of standard Amphotericin B, with significant cytotoxicity and could be potential candidates for the treatment of leishmaniasis. The UV–visible spectroscopic studies revealed that ligand and its complexes bind with DNA via intercalative mode of interaction leading to hypochromism and minor bathochromic or hypsochromic shifts.

Functional properties of chitosan built nanohydrogel with enhanced glucose-sensitivity

A new approach to design multifunctional chitosan based nanohydrogel with enhanced glucose sensitivity, stability, drug loading and release profile are reported. Two approaches were followed for functionalization of chitosan based nanohydrogel with 3-APBA via EDC and 3-APTES. The effective functionalization, structure and morphology of Chitosan based IPN respectively were confirmed by FTIR, SEM and AFM. At physiological conditions, the glucose-induced volume phase transition and release profile of the model drug Alizarin Red with 1,2-diol structure (comparative to insulin as a drug as well as a dye for bio separation) were studied at various glucose concentrations, pH and ionic strengths. The results suggested a new concept for diabetes treatment and diols sensitivity in view of their potential hi-tech applications in self-regulated on-off response to the treatment (drug delivery and bio separation concurrently).

Synthesis and physicochemical investigation of chitosan-built hydrogel with induced glucose sensitivity

ABSTRACT There is an urgent need to treat diabetes, and therefore, this work reports on a chitosan-built hydrogel functionalized by a glucose sensing moiety, which simulates pancreatic activity. The effect of external stimuli on various internal properties was investigated to establish the action of the hydrogel. The model drugs, fluorescein (D1) and rhodamine (D2), with a diol architecture, were investigated spectroscopically with 75.94% loading and 65.63% release. Consequently, a ligand to glucose ratio of 2:1 in comparison with a ligand to model drug ratio of 1:1 was addressed. The system was expected to lead to findings on applications for the self-controlled release of insulin in response to blood glucose levels. GRAPHICAL ABSTRACT

Synthesis, characterization and cellulose dissolution capabilities of ammonium-based room temperature ionic liquids (RTILs)

Abstract Green synthesis of room temperature ionic liquids (RTILs), are presented as friendly and challenging solvents for the effective dissolution of oil palm-lignocellulosic biomass. A series of Bronsted acidic-ionic liquids were prepared by the direct neutralization of diethyl dimethyl ammonium hydroxide with several (economical and environmental friendly) Bronsted acids as RTILs. The structural and physicochemical characterization was performed by applying various techniques as Fourier transform infrared (FT-IR), nuclear magnetic resonance (NMR), thermo gravimetric analysis (TGA), differential scanning calorimetry (DSC), zeta-nanosizer and dynamic light scattering (DLS) respectively, to state the effect of anion on the extended cellulose dissolution capabilities of the synthesized RTILs under mild conditions. As a polysaccharide solvent, diethyl dimethyl ammonium phosphate (A1P) showed the extreme capability to extract 65 % of cellulose from biomass without any pretreatment for 30 min. The present study could be a significant step toward the synthesis of efficient RTILs and generating upgraded cellulose for Hi-tech engineered composites and energy concerns.

Synthesis and functionalization of chitosan built hydrogel with induced hydrophilicity for extended release of sparingly soluble drugs

Abstract Addressing the functional biomaterials as next-generation therapeutics, chitosan and alginic acid were copolymerized in the form of chemically crosslinked interpenetrating networks (IPNs). The native hydrogel was functionalized via carbodiimide (EDC), catalyzed coupling of soft ligand (1,2-Ethylenediamine) and hard ligand (4-aminophenol) to replace –OH groups in alginic acid units for extended hydrogel- interfaces with the aqueous and sparingly soluble drug solutions. The chemical structure, Lower solution critical temperature (LCST ≈ 37.88 °C), particle size (Zh,app ≈ 150–200 nm), grain size (160–360 nm), surface roughness (85–250 nm), conductivity (37–74 mv) and zeta potential (16–32 mv) of native and functionalized hydrogel were investigated by using FT-IR, solid state-13C-NMR, TGA, DSC, FESEM, AFM and dynamic light scattering (DLS) measurements. The effective swelling, drug loading (47–78%) and drug release (53–86%) profiles were adjusted based on selective functionalization of hydrophobic IPNs due to electrostatic complexation and extended interactions of hydrophilic ligands with the aqueous and drug solutions. Drug release from the hydrogel matrices with diffusion coefficient n ≈ 0.7 was established by Non- Fickian diffusion mechanism. In vitro degradation trials of the hydrogel with a 20% loss of wet mass in simulated gastric fluid (SGF) and 38% loss of wet mass in simulated intestinal fluid (SIF), were investigated for 400 h through bulk erosion. Consequently, a slower rate of drug loading and release was observed for native hydrogel, due to stronger H-bonding, interlocking and entanglement within the IPNs, which was finely tuned and extended by the induced hydrophilic and functional ligands. In the light of induced hydrophilicity, such functional hydrogel could be highly attractive for extended release of sparingly soluble drugs.

Synthesis, characterization, and biological activity of organotin(IV) complexes with 4-oxo-4-[3-(trifluoromethyl)phenylamino]butanoic acid

Metal complexes display functional interfaces for association with and stimulation of certain enzymes, that are liable to transfer genetic information in DNA for synthesis of specific proteins. Biological activity of five organotin carboxylates based on the ligand, 4-oxo-4-[3-(trifluoromethyl)phenylamino]butanoic acid, such as [Bu3SnL] (1), [Ph3SnL] (2), [Me2SnL2] (3), [Bu2SnL2] (4), and [Ph2SnL2] (5) have been synthesized and their biological activity as a function of substitution on the ligand was tested. Structure of the complexes was evaluated by elemental analysis, FT-IR and 1H, and 13C NMR spectra. FT-IR data and theoretical calculations revieled that the ligand acted as bidentate in complexes 1–5. NMR data revealed four and six coordinated geometry of tin in solutions. The HOMO–LUMO study indicated thermodynamic stability of the complexes. AFM confirmed catalytic potential of the synthesized complexes. Biological screening showed that, with few exceptions, all the complexes exhibited significant activity against various bacterial and fungal strains. UV-Vis study confirmed that the ligand and its complexes binded to DNA via intercalative interactions.

Organotin(IV) O -butyl carbonodithioates: Synthesis, characterization, in vitro bioactivities, and interaction with SS-DNA

Organotin(IV) O-butyl carbonodithioates [Me2SnL2], [Bu2SnL2], [Ph2SnL2], [Bu3SnL], and [Ph3SnL], where L = C4H9OCS2–, have been successfully synthesized and characterized by FT-IR, 1H and 13C NMR, and single crystal X-ray analysis. The ligand coordinates to the tin atom via the carbonodithioate group. According to the X-ray diffraction data, the tin atom in [Me2SnL2] has distorted tetrahedral geometry. The synthesized compounds were screened in vitro for antibacterial, antifungal, antileishmanial, cytotoxic, and protein kinase inhibitory activities. The complexes [Bu3SnL] and [Ph3SnL] exhibited the highest anti-leishmanial activity that exceeded the activity of the reference drug amphotericin B, probably by blocking the function of parasitic mitochondria due to which it restricts further growth of the organisms. The ligand and the complexes have been shown to bind to DNA via intercalative interactions resulting in hypochromic effect with a minor red shift as confirmed by UV-Vis spectroscopic studies.