The interaction between synthetic polymer nanoparticles (NPs) and biomacromolecules (e.g. proteins, lipids and polysaccharides) can profoundly influence the NPs fate and function. Polysaccharides (e.g. heparin/heparin sulfate) are a key component of cell surfaces and the extracelluar matrix and play critical roles in many biological processes. We report a systematic investigation of the interaction between synthetic polymer nanoparticles and polysaccharides by ITC, SPR and an anticoagulant assay to provide guidelines to engineer nanoparticles for biomedical applications. The interaction between acrylamide nanoparticles (~30 nm) and heparin is mainly enthalpy driven with submicromolar affinity. Hydrogen bonding, ionic interactions and dehydration of polar groups are identified to be key contributions to the affinity. It has been found that high charge density and cross linking of the NP can contribute to high affinity. The affinity and binding capacity of heparin can be significantly diminished by an increase in salt concentration while only slightly decreased with an increase of temperature. A striking difference in binding thermodynamics has been observed when polymer nanoparticle’s main component is changed from acrylamide (enthalpy driven) to N-isopropylacryalmide (entropy driven). This change in thermodynamics leads to different responses of these two types of polymer NPs to salt concentration and temperature. Select synthetic polymer nanoparticles have also been shown to inhibit protein-heparin interactions and thus offer the potential for therapeutic applications.
Co(II), Ni(II), Cu(II) and Mn(II) complexes synthesized by reflux of 6-bromo-3-(3-(4-chlorophenyl)acryloyl)-2Hchromen-2-one, Ciprofloxacin and various transition metal. 1 H, 13 C, IR and ESI Mass confirm the formation of ligand. The metal complexes were characterized on the basis of various spectroscopic techniques like IR studies and elemental analysis while the geometry of complexes was octahedral which is confirmed by electronic spectra and thermogravimetric analysis. The compounds were subjected to antimicrobial, antioxidant and anti-tubercular activity screening using serial broth dilution method and Minimum Inhibitory Concentration (MIC) is determined. Mn(II) complex has shown significant antifungal activity with an MIC of 6.25 µg/ml while Cu(II) complex is noticeable for antibacterial activity at the same concentration. Anti-TB activity of the ligand has enhanced on complexation with Ni(II) and Co(II) ions. While Ni(II) complex shows superior antioxidant activity than other complexes.
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