22 research outputs found
Microfluidic In Vitro Platform for (Nano)Safety and (Nano)Drug Efficiency Screening
Microfluidic technology is a valuable tool for realizing more in vitro models capturing cellular and organ level responses for rapid and animal‐free risk assessment of new chemicals and drugs. Microfluidic cell‐based devices allow high‐throughput screening and flexible automation while lowering costs and reagent consumption due to their miniaturization. There is a growing need for faster and animal‐free approaches for drug development and safety assessment of chemicals (Registration, Evaluation, Authorisation and Restriction of Chemical Substances, REACH). The work presented describes a microfluidic platform for in vivo‐like in vitro cell cultivation. It is equipped with a wafer‐based silicon chip including integrated electrodes and a microcavity. A proof‐of‐concept using different relevant cell models shows its suitability for label‐free assessment of cytotoxic effects. A miniaturized microscope within each module monitors cell morphology and proliferation. Electrodes integrated in the microfluidic channels allow the noninvasive monitoring of barrier integrity followed by a label‐free assessment of cytotoxic effects. Each microfluidic cell cultivation module can be operated individually or be interconnected in a flexible way. The interconnection of the different modules aims at simulation of the whole‐body exposure and response and can contribute to the replacement of animal testing in risk assessment studies in compliance with the 3Rs to replace, reduce, and refine animal experiments
Toxicity and cellular uptake of gold nanoparticles: what we have learned so far?
Gold nanoparticles have attracted enormous scientific and technological interest due to their ease of synthesis, chemical stability, and unique optical properties. Proof-of-concept studies demonstrate their biomedical applications in chemical sensing, biological imaging, drug delivery, and cancer treatment. Knowledge about their potential toxicity and health impact is essential before these nanomaterials can be used in real clinical settings. Furthermore, the underlying interactions of these nanomaterials with physiological fluids is a key feature of understanding their biological impact, and these interactions can perhaps be exploited to mitigate unwanted toxic effects. In this Perspective we discuss recent results that address the toxicity of gold nanoparticles both in vitro and in vivo, and we provide some experimental recommendations for future research at the interface of nanotechnology and biological systems
Hollow PdAg-CeO2 heterodimer nanocrystals as highly structured heterogeneous catalysts
In the present work, hollow PdAg-CeO2 heterodimer nanocrystals (NCs)
were prepared and tested as catalysts for the selective hydrogenation of
alkynes. These nanostructures combine for the first time the beneficial
effect of alloying Pd with Ag in a single NC hollow domain with the
formation of active sites at the interface with the CeO2 counterpart in
an additive manner. The PdAg-CeO2 NCs display excellent alkene
selectivity for aliphatic alkynes. For the specific case of
hydrogenation of internal alkynes such as 4-octyne, very low
over-hydrogenation and isomerization products were observed over a full
conversion regime, even after prolonged reaction times. These catalytic
properties were remarkably superior in comparison to standard catalysts.
The promotion of Ag on the moderation of the reactivity of the Pd phase,
in combination with the creation of interfacial sites with the CeO2
moiety in the same nanostructure, is pointed as the responsible of such
a remarkable catalytic performance