Biopersistence and biodurability have the potential to influence the long-term toxicity and hence pathogenicity of particles that deposit in the body. Therefore, biopersistence and biodurability are considered to be important parameters needed for the risk assessment of particles and fibres. Dissolution, as a measure of biodurability, is dependent on the chemical and physical properties (size, surface area, etc.) of particles and fibres and also of the suspension medium including its ionic strength, pH, and temperature. In vitro dissolution tests can provide useful insights as to how particles and fibres may react in biological environments; particles and fibres that release ions at a higher rate when suspended in vitro in a specific simulated biological fluid will be expected to do so when they exist in a similar biological environment in vivo. Dissolution of particles and fibres can follow different reaction kinetics. For example, the majority of micro-sized particles and fibres follow zero-order reaction kinetics. In this case, although it is possible to calculate the half-time of a particle or fibre, such calculation will be dependent on the initial concentration of the investigated particle or fibre. Such dependence was eliminated in the shrinking sphere and fibre models where it was possible to estimate the lifetimes of particles and fibres as a measure of their biodurability. The latter models can be adapted for the dissolution studies of nanomaterials. However, the models may apply only to nanomaterials where their dissolution follows zero-order kinetics. The dissolution of most nanomaterials follows first-order kinetics where dependence on their initial concentration of the investigated nanomaterials is not required and therefore it is possible to estimate their half-times as a measure of their biodurability. In dissolution kinetics for micro-sized and nano-sized particles and fibres, knowledge of dissolution rate constants is necessary to understand biodurability. Unfortunately, many studies on dissolution of nanoparticles and nanofibres do not determine the dissolution rates and dissolution rate constants. The recommendation is that these parameters should be considered as part of the important descriptors of particle and fibre physicochemical properties, which in turn, will enable the determination of their biodurability.

We have developed a high-throughput system to synthesise and explore up to 96 heterogeneous catalysts at the same time.The system was developed as a proof of concept, using a standard glass plate and a 3D printed 96-well plate. Nanodroplets of catalyst formulations were transferred to the glass plate using an acoustic liquid handler and upon heat treatments, the miniature mesoporous metal oxide (MMO) catalysts were formed. The 3D printed bottomless 96-well plate was fixed to the glass plate, to give 96 individual wells, each containing a catalyst. Four catalyst plates were prepared (Co 3 O 4 -, Au/Co 3 O 4 -, Pd/Co 3 O 4 -and Co/Mn-MMO) to be screened for their activity in the oxidation of morin, as a model reaction. The observed reaction rates (k obs ) for each catalyst were calculated to identify the most active catalyst. The general method described herein requires microscopic amounts of catalysts with derivates of the catalyst's composition.

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BACKGROUND Conventional methods used to evaluate the activity of catalysts are time consuming and tedious, which only several catalysts can successfully be discovered. By employing robotics, this approach can be shorted tremendously. A robotics‐assisted high‐throughput system for the fast and effective catalytic evaluation of Pd‐ and Au‐polyvinylpyrrolidone (PVP) nanoparticles (NPs) was investigated. RESULTS Palladium and gold PVP NPs were synthesised by employing ethylene glycol in the polyol method. These NPs were evaluated for the oxidation of morin using a high‐throughput system, including a liquid handling robot, a 96‐well plate and a microplate reader. The catalyst concentration variation step for both catalysts (Pd‐ and Au‐PVP NPs) was performed in one experiment in a 96‐well plate. A concentration range, including 12 concentrations in four replicates, was investigated simultaneously. Therefore, with one experiment, the optimal concentration of both catalysts could be determined. A similar approach was followed for the concentration variation steps of morin and hydrogen peroxide at different temperatures. This was done to determine the effect of concentration on the observed rate (kobs). CONCLUSION The catalytic oxidative degradation of morin can be investigated in a fast and effective way by employing robotics and a high‐throughput system. This system can also be applied to screen catalysts (homogeneous and heterogeneous catalyst) and the parallel synthesis of nanoparticles – particularly dendrimer‐encapsulated nanoparticles. © 2021 Society of Chemical Industry (SCI).

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