Temperature-responsive peptide-mimetic coating based on poly(N-methacryloyl-l-leucine): Properties, protein adsorption and cell growth

Pyrene functionalized side chain alanine and histidine containing copolyacrylates prepared by free radical copolymerization

“…Analysis of the 1 H NMR spectrum of poly(Ac‐ L ‐Ala‐ co ‐Ac‐ L ‐His) [Figure (a)] indicated the presence of resonance signals attributed to the protons of NH groups from L ‐histidine and L ‐alanine (8.8 and 7.4 ppm, respectively), methyne protons from imidazole group (8.65 and 7.35 ppm), methyne protons of the chiral carbons from the two amino acids (4.48 ppm for Ac‐ L ‐Ala and 4.3 ppm for Ac‐ L ‐His), methylene protons adjacent to the imidazole ring (3.5 ÷ 3 ppm), methyne and methylene protons from the main chain (2.5 ÷ 1.9 ppm) and methyl protons of alanine (1.42 ppm), which was in agreement with the proposed structure. These assignments were confirmed by the analysis the J ‐coupled protons from the two‐dimensional diagram 1 H,H‐COSY of poly(Ac‐ L ‐Ala‐ co ‐Ac‐ L ‐His) shown in Figure (b).…”

“…Thus, at pH = 6 the chiroptical copolyacrylate exhibited a strong negative CD signal at 190 nm (the intensity of the peak is −68.3 deg cm 2 /dmol) and a weak positive CD signal at approximate 219 nm, which were attributed to the n–π* electronic transition of carboxyl chromophore and π–π* transition of amide chromophore, respectively . When the pH value was adjusted at 9, the negative CD signal from 190 nm was slightly shifted to 192 nm simultaneously with decreasing of the peak intensity at −74.0 deg cm 2 ·dmol − . The same behavior could be noted at pH = 11 by shifting the negative band at 197 nm and at a higher ellipticity value than in the previous case, [θ] = −59.4 deg·cm 2 /dmol.…”

“…Subsequently, the functionalization of the formed copolymer, poly(Ac‐ L ‐Ala‐ co ‐Ac‐ L ‐His) [Scheme (a)], with a certain quantity of fluorophore was performed by esterification of its carboxylic groups with 1‐pyrene‐methanol in the presence of N,N' ‐dicyclohexylcarbodiimide, in order to obtain an optically active photopolymer which contained pyrene rings in the side chains, (poly(Ac‐ L ‐Ala‐ co ‐Ac‐ L ‐His)‐Py) [Scheme (b)]. The chemical structure of the synthesized compounds was elucidated by 1 H/ 13 C NMR, 1 H,H‐COSY, and FTIR spectroscopy.…”

“…The structures of all acrylated compounds were certified by 1 H NMR, C NMR, and 1 H,H COSY spectra using a Bruker Avance DRX 400 spectrometer with TMS as an internal standard and standard pulse sequences in the version with z ‐gradients, as given in Bruker with TopSpin 2.1 PL6 operating software, respectively. The FTIR absorption spectra were run by means of a Bruker Vertex spectrometer using KBr pellets.…”

“…During the past decade, significant scientific interest has been focused on the synthesis of smart amino acid‐based polymers with characteristic stimuli responsive properties as a result of their ability to tune the physicochemical properties upon the action of external stimuli (pH, temperature, light irradiation, etc. ) affecting the conformation of polymeric materials, degradability, solubility, and self‐assembly behavior in aqueous media . The presence of ionizable groups in these polymers, such as carboxylic acids and/or amines, that can accept or donate protons in response to variations in environmental pH, enhances the solubility, determines the responsive properties and allows the post‐polymerization modification reactions to generate various other chain architectures.…”