Effect of Motif‐Programmed Artificial Proteins on the Calcium Uptake in a Synthetic Hydrogel

Abstract

Motif-programmed artificial proteins with mineralization-related activity were covalently immobilized onto the surface of a hydrogel, poly(2-hydroxyethyl methacrylate) (PHEMA). We investigated the influence of assaying conditions upon the ability of three selected proteins (PS64, PS382 and PS458) to modulate calcification in vitro. A long-term assay measuring the real amount of calcium phosphate phase in the protein-modified PHEMA showed that all proteins enhanced the uptake of calcium by the hydrogel. For PS382 and PS458, this is a behaviour opposite to that displayed when the same proteins were tested in a free state by a rapid solution assay. Such difference may be attributed to a restricted mobility of the proteins due to immobilization.

Mineralization of Hydrogels for Bone Regeneration

“…Chirila et al 105 immobilized three different artificial protein sequences onto pHEMA hydrogels. These sequences (two of them can be found in nacrein and the third is present in dentin matrix acidic phosphoprotein) were tested in vitro and their ability to nucleate calcium phosphate was assessed in solutions.…”

Incorporation of Exogenous RGD Peptide and Inter-Species Blending as Strategies for Enhancing Human Corneal Limbal Epithelial Cell Growth on Bombyx mori Silk Fibroin Membranes

“…The atom-percentages of S were 0.04 ± 0.02 at.-% in the sample control (unmodified BMSF), 0.09 ± 0.00 at.-% in the sample modified with 0.1 mg/mL GRGDSPC, and 0.12 ± 0.02 at.-% in the sample modified with 0.5 mg/mL GRGDSPC in the reaction medium, as mean values ± SEM ( n = 3). This region can be assigned to the sulphide bond and has been used as a signature for cysteine-containing peptides immobilized to synthetic polymers [54,55]. The weak intensity of the S 2 p signal may be related to a low penetration of the reaction activating agents [55,56], which restricts the presence of the bound peptide within an uppermost layer much thinner than the depth probed by the XPS (about 10 nm).…”

“…This region can be assigned to the sulphide bond and has been used as a signature for cysteine-containing peptides immobilized to synthetic polymers [54,55]. The weak intensity of the S 2 p signal may be related to a low penetration of the reaction activating agents [55,56], which restricts the presence of the bound peptide within an uppermost layer much thinner than the depth probed by the XPS (about 10 nm). As most of the XPS-probed substratum did not react with the peptide, it does not contain additional sulphur, and the resulting numerical value is diminished due to a greater background mass.…”

Interactions Between Inorganic and Organic Phases in Bone Tissue as a Source of Inspiration for Design of Novel Nanocomposites

“…The observed increase in decomposition temperatures analyzed by differential thermal/ thermal gravimetric analysis (DT/TGA) suggests the formation of a primary chemical bond between HA and gelatin, which is further supported by FTIR analysis, confirming the induction of a red-shift of the 1339 cm -1 band of gelatin due to the chemical bonding between Ca 2 + of HA and carboxyl ions of gelatin molecules. 122 Chirila et al 123 postulated that complex artificial proteins can be synthesized, which either accelerate or decelerate mineralization, thereby offering new opportunities for modulation of composite properties. To this end, motif-programmed artificial proteins were covalently immobilized with mineralization-related activity onto the surface of a poly(2-hydroxyethyl methacrylate) (pHEMA) hydrogel, and the influence of assaying conditions upon the ability of three artificial proteins (two proteins incorporating nacrein repetitive motifs [PS382 and PS458] and one protein incorporating DMP1 motifs [PS64]) 124,125 to modulate calcification in vitro was investigated.…”

“…126 Such a difference was attributed to a restricted mobility of the proteins due to immobilization. 123 Mineralized polymers can also be synthesized through intrafibrillar mineralization of collagen by applying a polymerinduced liquid-precursor (PILP) mineralization process. In an in vitro model system, Gower and his coworkers 66 used polyaspartate to mimic the acidic NCPs engaged in bone formation.…”