Experimental and Theoretical Studies on Indigo-Dye-Modified Conjugated Polymers.

The present work reports the synthesis of indigo-dye-incorporated polyaniline (Indigo-PANI), poly(1-naphthylamine) (Indigo-PNA), poly(o-phenylenediamine) (Indigo-POPD), polypyrrole (Indigo-PPy), and polythiophene (Indigo-PTh) via an ultrasound-assisted method. The synthesized oligomers were characterized using FTIR, UV-visible spectroscopy, X-ray diffraction (XRD), scanning electron microscopy (SEM), fluorescence studies, and thermogravimetric analysis (TGA). The experimental data were theoretically compared to analyze the vibrational and electronic spectra via time-dependent density-functional theory (TD-DFT) by applying the Becke, three-parameter, and Lee-Yang-Parr (B3LYP) method with a 6-311G (d,p) basis set. The experimental, theoretical vibrational, and electronic spectra were found to be in close agreement and confirmed the successful incorporation of indigo dye in PANI, PNA, POPD, PPy, and PTh. These studies confirmed that multifunctional oligomers could be synthesized through a facile technique by incorporating dye moieties to enhance their optoelectronic properties, allowing them to be utilized as near-infrared-emitting probes for photodynamic therapy.

Sustained Release Studies of Metformin Hydrochloride Drug Using Conducting Polymer/Gelatin-Based Composite Hydrogels.

The present work highlights the synthesis and characterization of conducting polymer (CP)-based composite hydrogels with gelatin (GL-B) for their application as drug delivery vehicles. The spectral, morphological, and rheological properties of the synthesized hydrogels were explored, and morphological studies confirmed formation of an intense interpenetrating network. Rheological measurements showed variation in the flow behavior with the type of conducting polymer. The hydrogels showed a slow drug release rate of about 10 h due to the presence of the conducting polymer. The release kinetics were fitted in various mathematical models and were best fit in first order for PNA-, POPD-, and PANI-based GL-B hydrogels, and the PVDF/GL-B hydrogel was best fit in the zero-order models. The drug release was found to follow the order: POPD/GL-B > PANI/GL-B > PVDF/GL-B.

Evaluation of naked-eye sensing and anion binding studies in meso-fluorescein substituted one-walled calix[4]pyrrole (C4P).

In this paper, we have design, synthesized and fully characterized a new meso-fluorescein substituted one-walled calix[4]pyrrole (C4P7), obtained from simple and easily available starting materials such as fluorescein, 4-hydroxyacetophenone and pyrrole. The anion sensing studies reveal that the C4P7 system displays selective and sensitive naked-eye sensing towards fluoride, phosphate, and acetate anions with the limit of detection of 4.27 mg L-1, 6.4 mg L-1, and 5.94 mg L-1, respectively. Moreover, the C4P7 receptor displays good results of binding (host-guest, 1 : 1) towards a variety of anions. The 1 : 1 binding stoichiometry was further confirmed by means of Job's plots. TD-DFT calculations showed that the HOMO-LUMO gap decreases in all the complexes (C4P7@anions) in comparison to the free C4P7 system. The authors are of the opinion that this work may provide a good platform to explore calix[4]pyrrole chemistry in the arena of recognition/sensing of biologically significant analytes in future studies.

Dye Modified Phenylenediamine Oligomers: Theoretical Studies on Drug Binding for Their Potential Application in Drug Sensors.

The present work reports, for the first time, synthesis of dye incorporated o-phenylenediamine (OBB) with a view to obtain a conjugated oligomer with enhanced functionality. The structure was confirmed by IR studies, while the electronic transitions were confirmed by UV visible studies. The dye modified oligomer showed one order higher fluorescence intensity than the pristine Bismarck Brown (BB) dye. Confocal imaging showed red emission which could be utilized in near infra-red imaging. Density functional theory (DFT) studies were carried out to predict the theoretical properties of the oligomers. The energies of the highest occupied molecular orbital (HOMO) and the lowest unoccupied molecular orbital orbital were computed to explore how the HOMO energies of the reactants initiated the electronic interactions between them. The interaction energies were correlated to conjugation/hyper conjugation stabilization energies of the natural bond orbitals (NBO) via the DFT method using the B3LYP functional with the 6-311G(d) basis set on Gaussian 09 software. Drug binding was evaluated through simulation of interaction energy, (ΔEA-x) with drugs such as captopril, propranolol, thiazide, and fentanyl. The results predicted that the oligomer could be developed into a fentanyl drug sensor.

Efficient visible light-induced photocatalytic degradation of tetracycline hydrochloride using CuFe2O4 and PANI/CuFe2O4 nanohybrids.

Tetracycline hydrochloride (TC-HCl) is widely implemented as a wide-ranging antibacterial drug in medical care and animal husbandry, in spite of having negative effects on the environment and human health. Photocatalytic treatment is one of the popular techniques used to treat TC-HCl in wastewater. In this study, we have used CuFe2O4 and CuFe2O4/polyaniline (PANI) nanohybrids as photocatalysts for the degradation of TC-HCl. The metal ferrite and its nanohybrids were synthesized by co-precipitation method. FTIR, UV-Vis, XRD, and SEM-EDX were used to characterize the synthesized nanohybrids. The optical band gaps were estimated to be 2.74 eV for CuFe2O4, 1.72 eV for 1-PANI/CuFe2O4, 1.66 eV for 3-PANI/CuFe2O4, and 1.31 eV for 5-PANI/CuFe2O4. The photocatalytic performance of the nanohybrids appeared superior than pristine CuFe2O4, and maximum photocatalytic degradation was observed to be 86% within 120 min using 5-PANI/CuFe2O4 as the photocatalyst. The degraded fragments were analyzed by LCMS technique, and a tentative mechanism for the degradation of TC-HCl was proposed.

Microwave-assisted rapid degradation of Methyl red dye using Polyfuran/Polythiophene and its Co-oligomers as catalysts.

The work reports for the first time microwave-assisted degradation of Methyl Red (MR) dye using polythiophene (PTh), polyfuran (PFu) and its co-oligomers. The co-oligomers were synthesized by sonication using varying mol ratios of PFu/PTh (80:20, 50:50 and 20:80). The polymers and its co-oligomers were analyzed for their spectral and morphological properties using FTIR, UV-visible and scanning electron microscopy (SEM) coupled with elemental mapping. The oligomers as well as pristine polymers were used as microwave active catalysts to degraded Methyl Red (MR) dye. The degradation was found to follow the pseudo-first-order model. Maximum degradation of 99% was achieved using PFu/PTh-50/50 as catalyst. Scavenging tests were also carried out to confirm the generation of radicals responsible for the effective degradation of the dye. The LCMS studies were used to explore the degraded fragments and a plausible mechanism was proposed to reveal the degradation pathway.

Synthesis and characterization of pH-responsive conducting polymer/Na-alginate/gelatin based composite hydrogels for sustained release of amoxicillin drug.

Composite hydrogels of Na-Alginate (Na-ALG) and Gelatin (GEL) with conducting polymers (CPs) were synthesised using poly(o-phenylenediamine) (POPD), polyaniline (PANI), poly(1-naphthylamine (PNA) and poly(vinylenedine fluoride) (PVDF). The synthesised hydrogels were characterized using FTIR, scanning electron microscopy (SEM) rheology, swelling ability and in-vitro drug release characteristics. The purpose of this investigation was to determine whether these hydrogels could be used to deliver antibiotics for extended drug release. The composite hydrogels were loaded with antibiotic drug: amoxicillin in three different concentrations and the release was studied at intestinal fluid (pH 7.4) and gastric fluid (pH 1.2). Release kinetics was found to show best fit in zero order models at both pH values and showed prolonged release characteristics. The POPD-Na-ALG/GEL showed highest release at intestinal pH of 7.4, while PVDF-Na-ALG/GEL showed highest release at gastric pH at 1.2.

Visible-light induced degradation of diphenyl urea and polyethylene using polythiophene decorated CuFe2O4 nanohybrids.

The present work reports facile synthesis of CuFe2O4 nanoparticles via co-precipitation method and formulation of its nanohybrids with polythiophene (PTh). The structural and morphological properties were investigated using fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), scanning electron microscopy coupled with energy dispersive spectra (SEM-EDS) and UV-Vis spectroscopy. The band gap was found to decrease with increase in the loading of PTh and was found to be 2.52 eV for 1-PTh/CuFe2O4, 2.15 eV for 3-PTh/CuFe2O4 and 1.89 eV for 5-PTh/CuFe2O4. The nanohybrids were utilized as photocatalysts for visible light induced degradation of diphenyl urea. Diphenyl urea showed 65% degradation using 150 mg catalyst within 120 min. Polyethylene (PE) was also degraded using these nanohybrids under visible light as well as microwave irradiation to compare its catalytic efficiency under both conditions. Almost 50% of PE was degraded under microwave and 22% under visible light irradiation using 5-PTh/CuFe2O4. The degraded diphenyl urea fragments were analyzed using LCMS and a tentative mechanism of degradation was proposed.

Recent advances in the utilization of polyaniline in protein detection: a short review.

Various reports have been published based on covalently attaching biomolecules to polyaniline (PANI). The functional groups connected to the surface of polymeric units determine the immobilization method as well as the method of detection. The present mini-review aims at covering recent advances in the field of protein binding and detection using PANI. Several proteins have been attached to the polymer using different immobilization techniques. The application of PANI in protein detection has also been discussed along with the future scope of these materials in diagnosis and detection.

A short review on the synthesis and advance applications of polyaniline hydrogels.

Conductive polymeric hydrogels (CPHs) exhibit remarkable properties such as high toughness, self-recoverability, electrical conductivity, transparency, freezing resistance, stimulus responsiveness, stretch ability, self-healing, and strain sensitivity. Due to their exceptional physicochemical and physio-mechanical properties, among the widely studied CPHs, polyaniline (PANI) has been the subject of immense interest due to its stability, tunable electrical conductivity, low cost, and good biocompatibility. The current state of research on PANI hydrogel is discussed in this short review, along with the properties, preparation methods, and common characterization techniques as well as their applications in a variety of fields such as sensor and actuator manufacturing, biomedicine, and soft electronics. Furthermore, the future development and applications of PANI hydrogels are also mentioned.

In-silico study for the screening and preparation of ionic liquid-AVDs conjugate to combat COVID-19 surge.

The pandemic due to COVID-19 caused by SARS-CoV-2 has led to the recorded deaths worldwide and is still a matter of concern for scientists to find an effective counteragent. The combination therapy is always been a successful attempt in treating various threatful diseases. Recently, Ionic liquids (ILs) are known for their antiviral activity. Fascinating tunable properties of ILs make them a potential candidate for designing the therapeutic agent. The concern while using ILs in biomedical field remains is toxicity therefore, choline-based ILs were used in the study as they are considered to be greener as compared to other ILs. In the present study strategically, we performed the blind molecular docking of antiviral drug (Abacavir, Acyclovir, and Galidesivir)-choline based ILs conjugates with the target protein (Mpro protease). The molecules were screened on the basis of binding energy. The data suggested that the combination of AVDs-ILs have greater antiviral potential as compared to the drugs and ILs alone. Further, the ADME properties and toxicity analysis of the screened conjugates was done which revealed the non-toxicity of the conjugates. Additionally, the energetic profiling of the ILs drugs and their conjugates was done using DFT calculations which revealed the stability of the conjugates and have a better option to be developed as a therapeutic agent. Also, from molecular dynamic simulation was done and results showed the stability of the complex formed between target protein and the designed conjugates of AVDs and ILs.

Conducting polymers/zinc oxide-based photocatalysts for environmental remediation: a review.

The accessibility to clean water is essential for humans, yet nearly 250 million people die yearly due to contamination by cholera, dysentery, arsenicosis, hepatitis A, polio, typhoid fever, schistosomiasis, malaria, and lead poisoning, according to the World Health Organization. Therefore, advanced materials and techniques are needed to remove contaminants. Here, we review nanohybrids combining conducting polymers and zinc oxide for the photocatalytic purification of waters, with focus on in situ polymerization, template synthesis, sol-gel method, and mixing of semiconductors. Advantages include less corrosion of zinc oxide, less charge recombination and more visible light absorption, up to 53%.

Experimental and Computational Studies of Azo Dye-Modified Luminol Oligomers: Potential Application in Lithium Ion Sensing.

With a view to design novel conjugated oligomers via a facile technique for its possible application in sensors, the present work reports oligomerization of Bismarck Brown (BB) dye with luminol. The structure was confirmed via IR studies, while the electronic transitions were confirmed by UV-visible studies. Morphological studies were carried out via SEM. Computational studies were carried out using the DFT method with a B3LYP 6-311G(d) basis set to investigate the optimized geometry, band gap, and vibrational and electronic transitions data. The HOMO-LUMO energies showed significant reduction in the band gap upon increasing the content of BB dye. The computational IR and UV spectra were noticed to be in close agreement with the experimental results. Spectrophotometric determination of Li ion was attempted using lithium chloride and a lithium carbonate drug commonly used in the treatment of bipolar disorder. The detection limit was noticed to be as low as 5.1 × 10-6 M, which could be used to design a Li ion sensor.

Synthesis and characterization of chitosan-supported Fe2O3 nanohybrids for rapid sonophotocatalytic degradation of 2,4,6-trichlorophenol.

The present study reports the design of heterogeneous photocatalytic system using Fe2O3 with chitosan (CS) as a matrix for the sonophotocatalytic degradation of 2,4,6-trichlorophenol (2,4,6-TCP). CS was chosen as a polymer matrix as it is abundant in nature, eco-friendly, and can be easily processed into microparticles, nanofibers, as well as nanoparticles and shows the tendency of adhesion towards a vast range of solid substrates besides serving as a chelating agent toward metallic oxides. The nanohybrids were characterized via Fourier transformation infrared spectrum (FT-IR), X-ray diffraction (XRD), scanning electron microscopy coupled with electron dispersive spectrum (SEM-EDS), thermogravimetric analysis (TGA), and UV-visible diffuse reflectance (UV-Vis-DRS) analyses. Infrared spectroscopy (IR) studies confirmed synergistic interaction between Fe2O3 and CS. The XRD measurements confirmed the crystalline morphology while SEM revealed formation of rod-like structures. The TGA studies confirmed higher thermal stability of CS/Fe2O3 as compared to pure CS. The optical band gap for CS and CS/Fe2O3 was calculated to be 3 eV and 2.25 eV, respectively, from diffuse reflectance spectral (DRS) studies. Rapid photocatalytic degradation of 2,4,6-TCP was observed under UV light irradiation in presence of CS and CS/Fe2O3 nanohybrids which revealed 83.19% and 95.20% degradation within a short span of 60 min. The degraded fragments were identified using liquid chromatography-mass spectrometry (LC-MS). The present study on the development of ecofriendly nanohybrid photocatalyst is expected to provide experimental basis for the future development of CS-based photocatalysts which can be easily processed into membranes/filters for the industrial scale degradation of toxic organic pollutants.

Highly efficient degradation of metronidazole drug using CaFe2O4/PNA nanohybrids as metal-organic catalysts under microwave irradiation.

Catalytic degradation based on microwave irradiation is an emerging technique which promises prompt and efficient catalytic degradation of organic pollutants. Calcium ferrite (CaFe2O4), poly(1-napththylamine) (PNA), and PNA/CaFe2O4 nanohybrids were synthesized via microwave-assisted technique. The properties of the as-prepared CaFe2O4, PNA, and PNA/CaFe2O4 nanohybrids were characterized by the thermogravimetric analysis (TGA), FTIR, XRD, SEM, and ultraviolet-visible spectrophotometry (UV-vis) analyses. The formation of inorganic-organic hybrids was confirmed by the FTIR and XRD studies. Loading of PNA was confirmed to be 8%, 16%, 32%, and 40% in CaFe2O4 which was established by TGA studies and the thermal stability was found to follow the order: CaFe2O4 > 8-PNA/CaFe2O4 > 16-PNA/CaFe2O4 > 32-PNA/CaFe2O4 > 40-PNA/CaFe2O4 > PNA. CaFe2O4 and PNA revealed band gap values of 3.42 eV and 2.60 eV respectively while for the PNA/CaFe2O4 nanohybrids, the values were found to be ranging between 2.46 and 3.00 eV. The PNA modified CaFe2O4 nanohybrids showed higher degradation efficiency towards metronidazole (MTZ) drug as compared with PNA and pure CaFe2O4. MTZ drug showed around 94% degradation within 21 min of microwave irradiation using 40-PNA/CaFe2O4 as catalyst. The enhanced catalytic activity was attributed to the high surface area of the nanohybrid catalyst as well as improved microwave catalytic activity of PNA. The reactive species responsible for degradation were confirmed by scavenger studies which formation of ·OH and O2·- radicals. Recyclability tests showed that the 40-PNA/CaFe2O4 nanohybrid exhibited 86% degradation of MTZ (90 mg/l) even after the third cycle, which reflected higher reusability of the catalyst. The MTZ fragments were identified using liquid chromatography-mass spectrometry (LC-MS).

Microwave-Assisted Degradation of Paracetamol Drug Using Polythiophene-Sensitized Ag-Ag2O Heterogeneous Photocatalyst Derived from Plant Extract.

Ag-Ag2O nanoparticles were synthesized using Osmium sanctum plant extract. The nanoparticles were sensitized with polythiophene (PTh) and were characterized via scanning electron microscopy with energy dispersive X-ray and elemental mapping, transmission electron microscopy, X-ray diffraction (XRD), Fourier-transform infrared, and UV-vis spectroscopy analyses. The elemental mapping results revealed that the samples were composed of C, S, Ag, and O elements which were uniformly distributed in the nanohybrid. XRD analysis confirmed the crystalline nature of Ag-Ag2O nanoparticles, and the average particle size was found to be ranging between 36 and 40 nm. The optical band gap of Ag-Ag2O, PTh, and Ag-Ag2O/PTh was found to be 2.49, 1.1, 1.5, and 0.68 eV. The catalytic activity of Ag-Ag2O, PTh, and Ag-Ag2O/PTh was investigated by degrading paracetamol drug under microwave irradiation. Around 80% of degradation was achieved during 20 min irradiation. All degradation kinetics were fitted to the pseudo-first-order model. A probable degradation pathway for paracetamol degradation was proposed based on liquid chromatography mass spectrometry analysis of degraded fragments.

Synthesis of nanohybrids of polycarbazole with α-MnO2 derived from Brassica oleracea: a comparison of photocatalytic degradation of an antibiotic drug under microwave and UV irradiation.

The present work describes the synthesis of α-MnO2 nanorods using a natural extract of Brassica oleracea (cabbage) and the formulation of its nanohybrids with polycarbazole, i.e., α-MnO2/PCz. Synergistic interaction between PCz and MnO2 is revealed from infrared spectroscopy (IR) studies while the composition is determined by X-ray photoelectron spectroscopy (XPS). The formation of α-MnO2 nanorods is confirmed via high-resolution transmission electron microscopy (HRTEM). The indirect bandgap of α-MnO2 is reported as 2.5 eV while for the nanohybrids it is found to be ranging between 2.3 and 2.5 eV. Results show that 91% and 89% of degradation is achieved within 30 min and 90 min under the microwave and UV irradiation respectively. Hydroxyl radicals (•OH) and superoxide (•O2-) radicals are responsible for photocatalytic degradation of the drug Bactrim DS which is confirmed by radical scavenging experiments. The nanohybrids show promising catalytic activity under UV as well as microwave irradiation.

Microwave-assisted rapid degradation of DDT using nanohybrids of PANI with SnO2 derived from Psidium Guajava extract.

The present work reports microwave-assisted synthesis of SnO2 nanoparticles via green route using Psidium Guajava extract. For the enhancement of catalytic activity, nanohybrids of SnO2 were formulated using different ratios of polyaniline (PANI) via ultrasound-assisted chemical polymerization. Formation of nanohybrids was confirmed via IR and XPS studies. The UV-vis DRS spectra of PANI/SnO2 revealed significant reduction in the optical band gap upon nanohybrid formation. Microwave-assisted catalytic efficiency of pure SnO2, PANI, PANI/SnO2 nanohybrids was investigated using DDT as a model persistent organic pollutant. The degradation efficiency of PANI/SnO2 was found to increase with the increase in the loading of PANI. Around 87% of DDT degradation was achieved within a very short period of 12 min under microwave irradiation using PANI/SnO2-50/50 as catalyst. The effect of DDT concentration was explored and the degradation efficiency of PANI/SnO2-50/50 catalyst was noticed to be as high as 82% in presence of 100 mg/L of DDT. The effect of microwave power on the degradation efficiency revealed 79% degradation using the same nanohybrid when exposed to microwave irradiation for 5 min under 1110 W microwave power. Scavenging studies confirmed the generation of OH, O2- radicals. The fragments with m/z values as low as 86 and 70 were confirmed by LCMS analysis. Recyclability tests showed that PANI/SnO2-50/50 nanohybrid exhibited 81% degradation of DDT (500 mg/L) even after the third cycle, which reflected high catalytic efficiency as well as remarkable stability of the catalyst. This green nanohybrid could therefore be effectively utilized for the rapid degradation of persistent organic pollutants.

Experimental and Theoretical Studies of Novel Azo Benzene Functionalized Conjugated Polymers: In-vitro Antileishmanial Activity and Bioimaging.

To study the effect of insertion of azobenzene moiety on the spectral, morphological and fluorescence properties of conventional conducting polymers, the present work reports ultrasound-assisted polymerization of azobenzene with aniline, 1-naphthylamine, luminol and o-phenylenediamine. The chemical structure and polymerization was established via Fourier transform infrared (FTIR) spectroscopy, nuclear magnetic resonance (1H-NMR) spectroscopy, while the electronic properties were explored via ultraviolet-visible (UV-vis) spectroscopy. Theoretical IR and UV spectra were computed using DFT/B3LYP method with 6-311G basis set while theoretical 1H-NMR spectra was obtained by gauge independent atomic orbital (GIAO) method. The theoretically computed spectra were found to be in close agreement with the experimental findings confirming the chemical as well as electronic structure of the synthesized polymers. Morphology was investigated by X-ray diffraction and transmission electron microscopy studies. Fluorescence studies revealed emission ranging between 530-570 nm. The polymers also revealed high singlet oxygen (1O2) generation characteristics. In-vitro antileishmanial efficacy as well as live cell imaging investigations reflected the potential application of these polymers in the treatment of leishmaniasis and its diagnosis.

A comparison of experimental and theoretical studies of benzoquinone modified poly(thiophene): effect of polymerization techniques on the structure and properties.

The present manuscript reports the synthesis of benzoquinone (BQ) modified polythiophene (PTh) by chemical and microwave-assisted polymerization techniques. The synthesized oligomers were investigated for their spectral, morphological and thermal properties via FTIR, UV-visible, scanning electron microscopy (SEM) and thermogravimetric (TGA) analyses. Theoretical calculations were performed by using Gaussian 09 software via the DFT/B3LYP method with the 6-311G basis set. FTIR confirmed the formation of hydroquinone modified PTh when the polymerization was carried out by magnetic stirring and ultrasonication, while the formation of BQ modified PTh was obtained by microwave irradiation. The electronic transitions obtained via experimental UV-visible studies were also found to be in close agreement with the theoretical spectra. SEM revealed a well-formed morphology comprising needle shaped rods for the oligomer synthesized under microwave irradiation. The TGA-DTA studies revealed low char content for the above oligomer, while the florescence studies revealed intense emission around 450 nm. The highest quantum yield was found to be 0.024, which also showed high singlet oxygen generation tendency as well as a high single oxygen quantum yield of 0.30 and could be utilized to design imaging probes applicable in photodynamic therapy.