Mechanisms for Covalent Immobilization of Horseradish Peroxidase on Ion-Beam-Treated Polyethylene

Abstract

The surface of polyethylene was modified by plasma immersion ion implantation. Structure changes including carbonization and oxidation were observed. High surface energy of the modified polyethylene was attributed to the presence of free radicals on the surface. The surface energy decay with storage time after treatment was explained by a decay of the free radical concentration while the concentration of oxygen-containing groups increased with storage time. Horseradish peroxidase was covalently attached onto the modified surface by the reaction with free radicals. Appropriate blocking agents can block this reaction. All aminoacid residues can take part in the covalent attachment process, providing a universal mechanism of attachment for all proteins. The native conformation of attached protein is retained due to hydrophilic interactions in the interface region. The enzymatic activity of covalently attached protein remained high. The long-term activity of the modified layer to attach protein is explained by stabilisation of unpaired electrons in sp2 carbon structures. A high concentration of free radicals can give multiple covalent bonds to the protein molecule and destroy the native conformation and with it the catalytic activity. The universal mechanism of protein attachment to free radicals could be extended to various methods of radiation damage of polymers.

Design of a Papain Immobilized Antimicrobial Food Package with Curcumin as a Crosslinker

“…The FTIR spectra of the LDPE ( Fig 3A ) has bands at 1462cm -1 which corresponds to methylene and methyl groups respectively. After UV treatment, new bands are formed at 1734 and 1640 cm -1 ( Fig 3B ) indicating the formation of C = O and C = C groups respectively [ 47 ]. FTIR spectrum of curcumin coated LDPE (before UV treatment) ( Fig 3C ) shows bands corresponding to OH (3290 cm -1 ), C = C (1626 cm -1 ) and C = O (1743 cm -1 ) groups, which are present in curcumin.…”

Bioengineering cobalt chromium cardiovascular stent biomaterial for surface enhancement and characterization

“…This variation was expected since surface free radicals undergo oxidation, with exposure to air over time (Bilek et al 2011). The timeline of the plasma kinetics study was similar to previous studies (Bilek et al 2011, Kondyurin et al 2012, although characterized for the first time with modified cobalt chromium -PAC-L605. Mildly hydrophilic material surface modifications are at an advantage in vivo, as they display favorable interactions with proteins, cells, blood, and decrease platelet adhesion (Seeger et al 1995, Waterhouse et al 2012.…”

Plasma ion implantation of 3D‐printed PEEK creates optimal host conditions for bone ongrowth and mineralisation

“…PIII treatment enables the covalent binding of biomolecules through the creation of surface and subsurface radicals, leading to the formation of covalent bonds with adsorbed molecules, especially biomolecules. [ 19,36 ] As examples, soluble amino acids, [ 37 ] antibodies [ 38 ] and oligonucleotides [ 39 ] are known to bind covalently to a PIII‐treated polymer surface. A consequence of the covalent binding induced by PIII is a stable interface that is immune to other molecules disrupting the surface in the process known as the Vroman effect.…”