Effect of the concentration of protein and nanoparticles on the structure of biohybrid nanocomposites

Abstract

We present colloidal nanocomposites formed by incorporating magnetite Fe3O4 nanoparticles (MNPs) with lysozyme amyloid fibrils (LAFs). Preparation of two types of solutions, with and without addition of salt, was carried out to elucidate the structure of MNPs‐incorporated fibrillary nanocomposites and to study the effect of the presence of salt on the stability of the nanocomposites. The structural morphology of the LAFs and their interaction with MNPs were analyzed by atomic force microscopy and small‐angle x‐ray scattering measurements. The results indicate that conformational properties of the fibrils are dependent on the concentration of protein, and the precise ratio of the concentration of the protein and MNPs is crucially important for the stability of the fibrillary nanocomposites. Our results confirm that despite the change in fibrillary morphology induced by the varying concentration of the protein, the adsorption of MNPs on the surface of LAF is morphologically independent. Moreover, most importantly, the samples containing salt have excellent stability for up to 1 year of shelf‐life.

Dependence of the Nanoscale Composite Morphology of Fe3O4 Nanoparticle-Infused Lysozyme Amyloid Fibrils on Timing of Infusion: A Combined SAXS and AFM Study

“…From the SAXS data, an ab initio shape model of the average solution structure of LAF was determined using the ATSAS program DAMMIF (inset, Figure 8 b) [ 29 ], which is represented by an assembly of dummy beads (blue). This model exhibits a bent and partially twisted appearance and is similar to the finding for the LAFs prepared by the same method and with the same physical conditions in our previous study [ 23 ]. From the pronounced oscillations of SAXS curves for the NPs, the spherical shape and a rather low dispersity were manifested.…”

“…In general, with increasing of the NP concentration, the contribution of the P20 form factor significantly contributes to the scattering signal, most prominently seen by the presence of the characteristic oscillations. The significant signal of P20 at a rather low mixing ratio of 10/300 (NP/LAF) for samples B10 and A10 stems from the much stronger scattering power of Fe 3 O 4 compared to the weaker scattering by lysozyme protein (~100 times less), which contributes at smaller scattering angles [ 23 ]. A direct comparison between both sets of samples reveals the most significant discrepancy at small scattering angles ( q < 0.2 nm −1 ), while the rest of the curves look similar.…”

“…Up until now, several studies have proven the effectiveness of the Fe 3 O 4 NPs, with or without surface modification, in imposing a destructive or agglomerating influence upon Aβ fibrils [ 7 , 8 , 9 , 10 , 17 , 18 , 19 , 20 , 21 , 22 , 23 ]. It was shown that, in biological media, nanoparticles interact with different proteins.…”

“…The process of nanoparticles’ adsorption on the protein surface can be influenced by several factors. More recently, in our previous work [ 23 ], the structural morphology of nanocomposites made from lysozyme amyloid fibrils (LAFs) and Fe 3 O 4 NPs was studied to find the optimal conditions to prepare stable magnetic-responsive nanocomposite materials composed of fibrils and nanoparticles, which might allow manipulation by external magnetic fields. It was shown that the stability depends on the ratio of LAFs and Fe 3 O 4 NPs.…”

Hyperthermia Induced by Near-Infrared Laser-Irradiated CsWO3 Nanoparticles Disintegrates Preformed Lysozyme Amyloid Fibrils

“…By cranking up the external temperature, an utter destruction of the LAFs and nanocomposites alongside the remains of crystalline structure of salt was observed, respectively, in Figure 8i,k when the treatment temperature reaches 70 • C, and surprisingly, as can be seen from Figure 8j,l, the remains of salt-based dendritic morphology of both types of samples found at 80 • C are structurally more substantial. The purpose of adding salt in the fibrillary model is to improve LAF's stability up to at least one year of shelf-life time as previously investigated in our past study where, regardless of the presence of salt, the aggregating action of lysozyme protein and formation of LAFs are not affected [42]. Thus, the resultant LAFs morphologies by the treatment of external thermal influence does not alter significantly even in the presence of salt.…”