Serum Proteins Enhance Dispersion Stability and Influence the Cytotoxicity and Dosimetry of ZnO Nanoparticles in Suspension and Adherent Cancer Cell Models

Abstract

Agglomeration and sedimentation of nanoparticles (NPs) within biological solutions is a major limitation in their use in many downstream applications. It has been proposed that serum proteins associate with the NP surface to form a protein corona that limits agglomeration and sedimentation. Here, we investigate the effect of fetal bovine serum (FBS) proteins on the dispersion stability, dosimetry, and NP-induced cytotoxicity of cationic zinc oxide nanoparticles (nZnO) synthesized via forced hydrolysis with a core size of 10 nm. Two different in vitro cell culture models, suspension and adherent, were evaluated by comparing a phosphate buffered saline (PBS) nZnO dispersion (nZnO/PBS) and an FBS-stabilized PBS nZnO dispersion (nZnO – FBS/PBS). Surface interactions of FBS on nZnO were analyzed via spectroscopic and optical techniques. Fourier transformed infrared spectroscopy (FTIR) confirmed the adsorption of negatively charged protein components on the cationic nZnO surface through the disappearance of surfaced-adsorbed carboxyl functional groups and the subsequent detection of vibrational modes associated with the protein backbone of FBS-associated proteins. Further confirmation of these interactions was noted in the isoelectric point shift of the nZnO from the characteristic pH of 9.5 to a pH of 6.1. In nZnO – FBS/PBS dispersions, the FBS reduced agglomeration and sedimentation behaviors to impart long-term improvements (>24 h) to the nZnO dispersion stability. Furthermore, mathematical dosimetry models indicate that nZnO – FBS/PBS dispersions had consistent NP deposition patterns over time unlike unstable nZnO/PBS dispersions. In suspension cell models, the stable nZnO – FBS/PBS dispersion resulted in a ~33 % increase in the NP-induced cytotoxicity for both Jurkat leukemic and Hut-78 lymphoma cancer cells. In contrast, the nZnO – FBS/PBS dispersion resulted in 49 and 71 % reductions in the cytotoxicity observed towards the adherent breast (T-47D) and prostate (LNCaP) cancer cell lines, respectively. Presence of FBS in the NP dispersions also increased the reactive oxygen species generation. These observations indicate that the improved dispersion stability leads to increased NP bioavailability for suspension cell models and reduced NP sedimentation onto adherent cell layers resulting in more accurate in vitro toxicity assessments.

ZnO Interactions with Biomatrices: Effect of Particle Size on ZnO-Protein Corona

“…In particular, NPs–protein corona formation has been well reported to affect cellular responses. For example, it was reported that the ZnO NPs–serum protein interaction influences cytotoxicity, showing lower or higher cytotoxicity when NPs were dispersed in serum proteins [ 11 , 15 , 16 ]. The aggregation of di-block copolymer NPs was found to be induced by fibrinogen, while the adsorption of albumin and complement component 3 (C3) protein on the surface of NPs triggered the activation of the immune complement cascade [ 17 ].…”

Application of ZnO Nanoparticles for Improving the Thermal and pH Stability of Crude Cellulase Obtained from Aspergillus fumigatus AA001

“…Apart from the biocompatibility, other fascinating properties of ZnO nanoparticles such as wide band gap, high exciting binding energy, and quantum effects may also support to make it an ideal candidate for improving the stability of cellulase enzyme. Moreover, since the hexagonal wurtzite structure of ZnO nanoparticles is thermodynamically stable, it may be helpful to influence the thermal stability of crude cellulase enzymes ( Ashrafi and Jagadish, 2007 ; Anders et al, 2015 ). Thus, use of such type of thermally stable ZnO nanoparticles treated cellulase can improve the economics of market involved in the enzyme-based hydrolysis of biomass, because the enzymatic degradation of cellulose needs the high enzyme loading which increases the production cost as well as economic demands.…”

Molecular Mechanisms, Characterization Methods, and Utilities of Nanoparticle Biotransformation in Nanosafety Assessments

“…[49,[122][123][124] Compared with water and neutral pH conditions, particle dissolution rates may speed up in acidic conditions as well as cell culture media. [49,125] Salts, vitamins, amino acids, peptides, and proteins that present in biological media can coordinate with the metal ions, and thus promote the dissolution process. Due to the large surface-to-volume ratio of ENMs, substantial defects on NP surfaces may also facilitate the dissolution process and the released ions may eventually reach to a homeostasis with particle aggregates.…”