Plasma polymerized functional supermagnetic Fe3O4 nanostructured templates for laccase immobilization: A robust catalytic system for bio-inspired dye degradation

Fe3O4 magnetic nanoparticles, synthesized using co-precipitation method, were epoxy functionalized via plasma polymerization of 2,3-epoxypropylmethacrylate (EPMA) precursor. The EPMA-functionalized Fe3O4 nanoparticles (EPMA-f-MN) were employed as templates for facile, one-step covalent immobilization of laccase enzyme at room temperature. Samples were rigorously characterized by FTIR, TGA, SEM, TEM, XRD techniques, while Mössbauer spectroscopy (MöS) and vibrating sample magnetometry (VSM) confirmed the supermagnetic nature of Fe3O4 nanoparticles. Activities of free and immobilized laccase (ImLac) were assayed by spectrophotometrically monitoring the enzymatic reduction of substrate 2,2-azino-bis(3-ethylthiazoline-6-sulfonate) (ABTS) at 420 nm, corresponding to the λmax of ABTS.+. In addition to possessing higher thermal stability and a broader pH tolerance window compared to free laccase, the supermagnetic property of the Fe3O4 renders the ImLac system conveniently recoverable and recyclable. Practical applicability of ImLac towards catalytic degradation of industrial dyes was also ably demonstrated using Acid Blue 193 (AB 193) as a commercially used model textile dye, which belongs to the family of azo dyes. Over 95% degradation of the dye was achieved within a period of 4 hours. ImLac could be used for more than 10 dye degradation cycles with >90 % of retention in enzyme activity.

Functionalization of Planet-Satellite Nanostructures Revealed by Nanoscopic Localization of Distinct Macromolecular Species

The development of a straightforward method is reported to form hybrid polymer/gold planet-satellite nanostructures (PlSNs) with functional polymer. Polyacrylate type polymer with benzyl chloride in its backbone as a macromolecular tracer is synthesized to study its localization within PlSNs by analyzing the elemental distribution of chlorine. The functionalized nanohybrid structures are analyzed by scanning transmission electron microscopy, electron energy loss spectroscopy, and spectrum imaging. The results show that the RAFT (reversible addition-fragmentation chain transfer) polymers' sulfur containing end groups are colocalized at the gold cores, both within nanohybrids of simple core-shell morphology and within higher order PlSNs, providing microscopic evidence for the affinity of the RAFT group toward gold surfaces.