Cardioprotective effect of tetra(aniline) containing terpolymers through miR-15a-5p and MFN-2 regulation against hypertrophic responses.

OBJECTIVE: Cardiac hypertrophy is a condition of abnormal cardiomyocyte enlargement accompanied by ventricular wall thickening. The study aims to investigate the role of miR-15a-5p in the regulation of mitofusin-2 (MFN-2) and to explore the cardioprotective effect of terpolymers ES-37 and L-37. METHODS: In this study, the Sprague Dawley rats' cardiac hypertrophic model was established by administering 5 mg/kg Isoproterenol subcutaneously every other day for 14 days. As treatment rats received NAC (50 mg/kg), NAC treatment (50 mg/kg NAC + 5 mg/kg ISO), ES-37 (1 mg/kg) and ES-37 treatment (1 mg/kg ES-37+5 mg/kg ISO), L-37 (1 mg/kg) and L-37 treatment (1 mg/kg L-37+5 mg/kg ISO). subcutaneously every other day for 14 days. NAC, ES 37 and L-37 were given after 1 h of Isoproterenol administration in treatment groups. Cardiac hypertrophy was confirmed through morphological and histological analysis. For estimation of oxidative stress profiling, ROS and TBARS and antioxidative profiling superoxide dismutase (SOD), Catalase, and Glutathione (GSH) levels were checked. Triglyceride, cholesterol, alanine transaminase (ALT), and aspartate transaminase (AST) were performed to evaluate levels of lipid profiling and liver profiling. Molecular expression analysis was checked through real-time PCR, and western blotting both at the transcriptional and translational levels. Molecular docking studies were performed to study the interactions and modes of binding between the synthetic polymers with three proteins (Mitofusin-2, DRP-1 and PUMA). All the studies were carried out using the AutoDock Vina software and the protein-ligand complexes were visualized in Biovia Discovery Studio. Cardiac hypertrophy was confirmed by the relative changes in the cellular structure of the heart by histopathological examination and physiological changes by estimating organ weights. Biochemical profiling results depict elevated oxidative and lipid profiles signify myocardial damage. N-acetyl cysteine (NAC), ES-37, and L-37 overcome the cardiac hypertrophic responses through attenuating oxidative stress and enhancing the antioxidative signaling mechanism. miR-15a-5p was identified as hypertrophic microRNA directly regulating the expression of Mitofusin-2 (MFN-2). Significantly increased expression of miR-15a-5p, Dynamin related protein 1 (Drp1), and P53 upregulated modulator of apoptosis (PUMA), was observed in the disease group, whereas MFN-2 expression was observed downregulated. N-acetyl cysteine (NAC), ES-37, and L-37 showed increased expression of antiapoptotic maker MFN-2 and decreased expression of miR-15a-5p, Drp1, and PUMA in treatment groups suggesting their cardioprotective role in attenuation of cardiac hypertrophy. An analysis of the docking results shows that ES-37 has greater binding affinity with the target proteins compared to L-37, with the highest binding values reported for MFN-2. CONCLUSION: The physiochemical properties of ES-37 and L-37 predicted it as a good drug-like molecule and its mechanism of action is predictably through inhibition of ROS. Molecular docking results shows that the polymer ES-37 has greater binding affinity with the target proteins compared to L-37, with the highest binding values reported for MFN-2. Thus, the study validates the role and targeting of miR-15a-5p and MFN-2 in cardiac hypertrophy as well as the therapeutic potential of NAC, ES-37, and L-37 in overcoming oxidative stress and myocardial damage.

Development of highly-reproducible hydrogel based bioink for regeneration of skin-tissues via 3-D bioprinting technology.

3-D Bioprinting is employed as a novel approach in biofabrication to promote skin regeneration following chronic-wounds and injury. A novel bioink composed of carbohydrazide crosslinked {polyethylene oxide-co- Chitosan-co- poly(methylmethacrylic-acid)} (PEO-CS-PMMA) laden with Nicotinamide and human dermal fibroblast was successfully synthesized via Free radical-copolymerization at 73 °C. The developed bioink was characterized in term of swelling, structural-confirmation by solid state 13C-Nuclear Magnetic Resonance (NMR), morphology, thermal, 3-D Bioprinting via extrusion, rheological and interaction with DNA respectively. The predominant rate of gelation was attributed to the electrostatic interactions between cationic CS and anionic PMMA pendant groups. The morphology of developed bioink presented a porous architecture satisfying the cell and growth-factor viability across the barrier. The thermal analysis revealed two-step degradation with 85 % weight loss in term of decomposition and molecular changes in the bioink moieties By applying low pressure in the range of 25-50 kPa, the optimum reproducibility and printability were determined at 37 °C in the viscosity range of 500-550 Pa. s. A higher survival rate of 92 % was observed for (PEO-CS-PMMA) in comparison to 67 % for pure chitosan built bioink. A binding constant of K ≈ 1.8 × 106 M-1 recognized a thermodynamically stable interaction of (PEO-CS-PMMA) with the Salmon-DNA. Further, the addition of PEO (5.0 %) was addressed with better self-healing and printability to produce skin-tissue constructs to replace the infected skin in human.

Ferrocene-Based Terpolyamides and Their PDMS-Containing Block Copolymers: Synthesis and Physical Properties.

Aromatic polyamides are well-known as high-performance materials due to their outstanding properties making them useful in a wide range of applications. However, their limited solubility in common organic solvents restricts their processability and becomes a hurdle in their applicability. This study is focused on the synthesis of processable ferrocene-based terpolyamides and their polydimethylsiloxane (PDMS)-containing block copolymers, using low-temperature solution polycondensation methodology. All the synthesized materials were structurally characterized using FTIR and 1H NMR spectroscopic techniques. The ferrocene-based terpolymers and block copolymers were soluble in common organic solvents, while the organic analogs were found only soluble in sulfuric acid. WXRD analysis showed the amorphous nature of the materials, while the SEM analysis exposed the modified surface of the ferrocene-based block copolymers. The structure-property relationship of the materials was further elucidated by their water absorption and thermal behavior. These materials showed low to no water absorption along with their high limiting oxygen index (LOI) values depicting their good flame-retardant behavior. DFT studies also supported the role of various monomers in the polycondensation reaction where the electron pair donation from HOMO of diamine monomer to the LUMO of acyl chloride was predicted, along with the calculation of various other parameters of the representative terpolymers and block copolymers.

A unique amphiphilic triblock copolymer, nontoxic to human blood and potential supramolecular drug delivery system for dexamethasone.

The drug delivery system (DDS) often causes toxicity, triggering undesired cellular injuries. Thus, developing supramolecules used as DDS with tunable self-assembly and nontoxic behavior is highly desired. To address this, we aimed to develop a tunable amphiphilic ABA-type triblock copolymer that is nontoxic to human blood cells but also capable of self-assembling, binding and releasing the clinically used drug dexamethasone. We synthesized an ABA-type amphiphilic triblock copolymer (P2L) by incorporating tetra(aniline) TANI as a hydrophobic and redox active segment along with monomethoxy end-capped polyethylene glycol (mPEG2k; Mw = 2000 g mol-1) as biocompatible, flexible and hydrophilic part. Cell cytotoxicity was measured in whole human blood in vitro and lung cancer cells. Polymer-drug interactions were investigated by UV-Vis spectroscopy and computational analysis. Our synthesized copolymer P2L exhibited tuned self-assembly behavior with and without external stimuli and showed no toxicity in human blood samples. Computational analysis showed that P2L can encapsulate the clinically used drug dexamethasone and that drug uptake or release can also be triggered under oxidation or low pH conditions. In conclusion, copolymer P2L is nontoxic to human blood cells with the potential to carry and release anticancer/anti-inflammatory drug dexamethasone. These findings may open up further investigations into implantable drug delivery systems/devices with precise drug administration and controlled release at specific locations.

Engineering electroactive and biocompatible tetra(aniline)-based terpolymers with tunable intrinsic antioxidant properties in vivo.

Under different pathological conditions, high levels of reactive oxygen species (ROS) cause substantial damage to multiple organs. To counter these ROS levels in multiple organs, we have engineered highly potent novel terpolymers. We found that combination of FDA-approved polyethylene glycol, fumaric acid moieties and electroactive tetra(aniline) by varying the content of tetra(aniline) results into a novel drug composition with biologically active and tunable intrinsic antioxidant properties. To test the intrinsic antioxidative properties of these novel terpolymers, we used alloxan to induce diabetes in rats where ROS generation is known to be higher. The systemic administration of terpolymers to the diabetic rats showed strong electroactive antioxidant behavior which not only normalized ROS levels, but also improved the levels of enzymatic antioxidants including superoxide dismutase (SOD), catalase (CAT), and glutathione (GSH). As a proof-of-principle, we here show TANI based novel drug composition of terpolymers with tunable intrinsic antioxidant properties in multiple organs.

Tunable Self-Assembled Nanostructures of Electroactive PEGylated Tetra(Aniline) Based ABA Triblock Structures in Aqueous Medium.

PEGylated tetra(aniline) ABA triblock structure PEG-TANI-PEG (2) consisting of tetra(aniline) (TANI) and polyethylene glycol (PEG) was synthesized by coupling the tosylated-PEG to boc-protected NH2/NH2 TANI (1) through a simple nucleophilic substitution reaction. Deprotection of 2 resulted in a leucoemeraldine base state of TANI (2-LEB), which was oxidized to stable emeraldine base (2-EB) state. 2-EB was doped with 1 M HCl to emeraldine salt (2-ES) state. FTIR, 1H and 13C NMR and UV-Vis-NIR spectroscopy, and MS (ESI) was used for structural characterization. The synthesized triblock structure exhibited good electroactivity as confirmed by CV and UV-Vis-NIR spectroscopy. Self-assembling of the triblock structure in aqueous medium was assessed by DLS, TEM, and SEM. Spherical aggregates were observed with variable sizes depicting the effect of concentration and oxidation of 2-LEB. Further, the aggregates showed acid/base sensitivity as evaluated by doping and dedoping of 2-EB with 1 M HCl and 1 M NH4OH, respectively. Future applications in drug delivery and sensors are envisaged for such tunable self-assembled nanostructures in aqueous media.