Lateral flow immunoassays (LFIAs) are a simple diagnostic device used to detect targeted analytes. Wasted and unused rapid antigen lateral flow immunoassays represent mass waste that needs to be broken down and recycled into new material components. The aim of this study was to recover gold nanoparticles that are used as markers in lateral flow immunoassays. For this purpose, a dissolution process with aqua regia was utilised, where gold nanoparticles were released from the lateral flow immunoassay conjugate pads. The obtained solution was then concentrated further with gold chloride salt (HAuCl₄) so that it could be used for the synthesis of new gold nanoparticles in the process of ultrasonic spray pyrolysis (USP). Various characterisation methods including scanning electron microscopy, transmission electron microscopy, ultraviolet-visible spectroscopy and optical emission spectrometry with inductively coupled plasma were used during this study. The results of this study showed that the recovery of gold nanoparticles from lateral flow immunoassays is possible, and the newly synthesised gold nanoparticles represent the possibility for incorporation into new products.

In this work, we developed a numerical approach based on an experimental platform to determine the working conditions on a cryoplatform and to predict and evaluate the cryogenic printing of hydrogels. Although hydrogels have good biocompatibility, their material properties make it difficult to print them with high precision and shape fidelity. To overcome these problems, a cryogenic cooling platform was introduced to accelerate the physical stabilisation of each deposited layer during the printing process. By precisely controlling solidification (crystallisation), each printed material can withstand its own weight to maintain shape fidelity, and the porosity of the scaffolds can also be controlled more selectively. The thermophysical properties of gelatine hydrogels were investigated to gain a better understanding of the phase change upon freezing. The corresponding material properties and experimental observations of gelatine solidification served as the basis for developing a computational fluid model (CFD) to mimic the solidification of gelatine hydrogels using a cryoplatform at different process conditions and extruder speeds. The goal was to develop a tool simple enough to predict acceptable process conditions for printing gelatine hydrogels using a cryoplatform.

In vitro models of the human nasal cavity are crucial for understanding the deposition dynamics of nasally administered drugs. Three-dimensional (3D) printing offers a powerful method for creating patient-specific, anatomically precise models for such experimental purposes. Background/Objectives: This study details the complete workflow for the development, design, and fabrication of a sectioned nasal cavity model intended for droplet deposition analysis of nasal sprays. Methods: A digital nasal cavity model was derived from medical imaging data and optimized for computer-aided design (CAD) operations. It was segmented into five therapeutically relevant regions: nasal vestibule, olfactory area, middle and upper turbinates, lower turbinate, and nasopharynx. Sections were 3D-printed in polypropylene for chemical compatibility, and a carbon fiber-reinforced fixation frame ensured precise alignment and airtight assembly. Results: Functional validation confirmed the model’s functional relevance through comparative deposition studies using automated actuation and high-performance liquid chromatography (HPLC) based regional quantification. Two devices with distinct spray characteristics (characterized separately by laser diffraction, plume geometry, and spray pattern imaging) were tested under varied administration conditions. The study demonstrated the model’s ability to discriminate between products, establishing a solid foundation for future investigations incorporating additional variables. Conclusions: Overall, the developed methodology provides a cost-effective and replicable platform for producing anatomically accurate, sectioned nasal cavity models. The newly developed in vitro system is well suited for detailed, region-specific analysis of nasal spray deposition, offering a valuable tool for pharmaceutical research and development.

In filling lines equipped with membrane separation devices in the form of filters energy, consumption is only one of the important working parameters, the other being sustainable filter performance in terms of separation efficiency. As the filling line is typically equipped with a valve, intermittent operation of the filter is an important form of its use. Whereas the overall energy consumption of the filtration process is governed by the continuous operation mode, the intermittent mode, characterised by opening/closing of the valve, contributes most to problems of filter failure, i.e., the breakthrough of filtered particles through the membrane. A model for determination of the energy intake of a microfiltration membrane during the opening and closing of a valve is presented in this work. The model is based on computational analysis of the pressure wave signals recorded during the opening/closing of the valve using Fourier transform, and expressed in a nondimensional filter area specific energy intake form. The model is applied to a case of constant pressure dead-end microfiltration with three filter types: a single membrane filter, a stacked filter and a pleated filter with filtration surface areas ranging from 17.7 cm² to 2000 cm². Both clean filters, as well as partially clogged filter cases are taken into account. Second order polynomial models of the energy intake are developed and evaluated based on extensive analysis of the experimental data. The analysis of energy intake results show that the largest energy intake was observed for the clean filter case. When membrane fouling occurs at the constant flow rate values it leads to larger energy intake, however, due to a decreasing specific flow rate during fouling these values do not exceed the clean filter case.

Drying is one of the oldest process technologies, which is used in different industrial applications. Drying process is complex physical process that involves coupled multiphase heat, mass and momentum transfer. As for example by spray drying process, local drying conditions inside the dryer affect to total drying time of porous particles. For this reason, the influence between particle and drying gas is very important. Through the drying process heat and mass exchange between particles and drying gas occurs, which results in local change of drying conditions. Two-way interaction (drying air to particle and particle to drying air) need to be considered to obtain accurate results. Fully coupled model for heat and mass transfer between particles and drying gas on the base of the Boundary Elements Method was developed in the present work, were particles were modelled as points. The results presented in this work show that two-way coupling between particles and drying gas is important in order to provide accurate results.