Significance of particle size and charge capacity in TiO2 nanoparticle-lipid interactions

Abstract

HypothesisThe activity of submicron sized titanium oxide (TiO 2 ) particles towards biomembrane models is coupled to their charge carrying capacity and their primary particle size. Experiments Electrochemical methods using a phospholipid layer on a mercury (Hg) supported membrane model have been used to determine the phospholipid monolayer activity of TiO 2 as an indicator of biomembrane activity. The particles were characterised for size by dynamic light scattering (DLS) and scanning electron microscopy (SEM) and charge by acid-base titration. Findings TiO 2 nanoparticles aggregate in 0.1 mol dm -3 solutions of KCl. The charge capacity of TiO 2 nanoparticles depends on their primary particle size and is unaffected by aggregation. TiO 2 particles of < 20 nm primary particle size interact significantly with phospholipid layers. Aggregation of these particles initially has a small effect on this interaction but long term aggregation influences the interaction whereby the aggregates penetrate the lipid layer rather than adsorbing on the surface. Fulvic acid does not inhibit the <20 nm particle/phospholipid interaction. P25 TiO 2 particles of larger particle size interact less strongly with phospholipid layers and the interaction is alleviated following particle aggregation. The semiconductor properties of TiO 2 are evident in voltammograms showing electron transfer to TiO 2 adsorbed on uncoated Hg.

Experimental Modeling of Flavonoid–Biomembrane Interactions

“…13,14,15 13 Although this sensing device was previously used to screen a number of membrane active 14 compounds from toxins to drugs, the current work aimed to reinforce the sensing system for food 15 ingredients for the first time. A successful application of such a sensing system can rapidly 16 establish a structure activity relationship of a variety of food compounds with membranes.…”

High-throughput electrochemical sensing platform for screening nanomaterial–biomembrane interactions

“…However, toxicity hazards associated with nanomaterials have been widely reported, with growing research in the field of nanotoxicology emphasising the need for screening techniques to characterise nanomaterial hazards [5][6][7][8][9][10][11][12]. As the applications for engineered nanomaterials continues to grow, high-throughput, in vitro screening solutions are essential to accelerate the process of evaluating the toxicity of novel engineered nanomaterials and to meet the demand for hazard identification [13,14].…”

“…Engineered nanomaterials can interact with cell membranes through adsorption onto the membrane, penetration through the membrane and endocytosis [17][18][19][20][21]. The understanding of nanomaterial cytotoxicity is challenging due to the complexity of cell membranes and the wide range of nanomaterial parameters, such as particle size, material and shape, that can influence the mechanisms of membrane interaction [5,7,10,11,17,21]. Cell-based in vitro toxicity assays are typically employed for the assessment of nanomaterial cytotoxicity, which are adapted for high-throughput screening through the use of high quantity multi-well plate platforms [22][23][24].…”

“…As the applications for engineered nanomaterials continues to grow, high-throughput, in vitro screening solutions are essential to accelerate the process of evaluating the toxicity of novel engineered nanomaterials and to meet the demand for hazard identification [13,14].High-throughput in vitro toxicity sensing technologies also provide an alternative to in vivo animal toxicity studies, which have ethical implications and are not economically feasible for screening a vast range of nanomaterials [3,15,16].Understanding cytotoxicity remains a particularly important and significant challenge in the field of nanotoxicology, as nanomaterials, due to their small size, can have unique properties that influence the mechanisms of interaction with cell membranes [17].Engineered nanomaterials can interact with cell membranes through adsorption onto the membrane, penetration through the membrane and endocytosis [17][18][19][20][21]. The understanding of nanomaterial cytotoxicity is challenging due to the complexity of cell membranes and the wide range of nanomaterial parameters, such as particle size, material and shape, that can influence the mechanisms of membrane interaction [5,7,10,11,17,21]. Cell-based in vitro toxicity assays are typically employed for the assessment of nanomaterial cytotoxicity, which are adapted for high-throughput screening through the use of high quantity multi-well plate platforms [22][23][24].…”

“…With advances in microfluidic flow cell technology and the possibility to automate processes, significant potential exists to improve the current screening methodology, as most recently described by Vakurov et al [7], to reduce fluid consumption, increase throughput and improve usability. Microfluidic flow cells offer significant benefits for high-throughput biosensing applications, by reducing fluid consumption in a low cost and easy to manufacture, high precision cell [41][42][43][44][45][46][47].…”