This feature article covers the recent applications of metal‐organic framework nanoparticles (MOF NPs) in photodynamic therapy (PDT) of cancer. It aims at giving the reader an overview about these two current research fields, i.e., MOF and PDT, and at highlighting the potential synergistic effect that could result from their association. After describing the general photophysics and photochemistry that underlie PDT, the relationship between photosensitizer (PS) properties and PDT requirements is discussed throughout the PSs historical development. This development reveals the advantages of using nanotechnology platforms for the creation of the ideal PS and leads us to define the fourth generation of PSs, which includes NPs built from the PS itself as porphysomes or PS‐based MOF NPs. Especially, the precise spatial control over the PS assembly into well‐defined MOF NPs, which keeps the PS in its monomeric form and prevents PS self‐quenching, appears as a notable feature to solve PS solubility and aggregation issues and therefore improves the PDT efficiency. Finally, we discuss the future perspectives of MOF NPs in PDT and shed light on how promising these nanomaterials are.
Cleaning of nanoparticles (< 50nm ) is becoming a major challenge in semiconductor manufacturing and the future use of traditional methods, such as megasonic cleaning, is questioned. In this paper the capability of megasonic cleaning to remove nanoparticles without inflicting damage to fragile structures is investigated. The role of dissolved gas in cleaning efficiency indicates that cavitation is the main cleaning mechanism. Consequently gas mass-balance analyses
are needed to optimize the performance of cleaning tools. When gas is dissolved in the cleaning present tools can remove nanoparticles down to about 30 nm using dilute chemistries at low temperature. Ultimate performance is limited by cleaning uniformity, which depends on tool design and operation. However no tool reached the target of high particle removal efficiency andlow damage. Significantly lower damage could only be obtained by decreasing the power, at the cost of a lower cleaning efficiency for nanoparticles. The development of damage-free megasonic is
discussed.
Multidisciplinary lab experiments
combining microfluidics, nanoparticle
synthesis, and characterization are presented. These experiments rely
on the implementation of affordable yet efficient microfluidic setups
based on perfluoroalkoxyalkane (PFA) capillary coils and standard
HPLC connectors in upper undergraduate chemistry laboratories. Fundamental
principles and concepts as well as practical tips for the rapid deployment
of microfluidics are presented. In-line membrane separation, the segmented-flow
regime, high-temperature experiments, and in-line analytical techniques
are illustrated by the preparation of inorganic nanoparticles (silver,
gold, and cadmium selenide or telluride) in microreactors. Besides
microfluidics, analytical techniques for nanoparticle analysis are
also illustrated.
Metal-enhanced processes arising from the coupling of a dye with metallic nanoparticles (NPs) have been widely reported. However, few studies have simultaneously investigated these mechanisms from the viewpoint of dye fluorescence and photoactivity. Herein, protoporphyrin IX (PpIX) is grafted onto the surface of silver core silica shell NPs in order to investigate the effect of silver (Ag) localized surface plasmon resonance (LSPR) on PpIX fluorescence and PpIX singlet oxygen ( O ) production. Using two Ag core sizes, we report a systematic study of these photophysical processes as a function of silica (SiO ) spacer thickness, LSPR band position and excitation wavelength. The excitation of Ag NP LSPR, which overlaps the PpIX absorption band, leads to the concomitant enhancement of PpIX fluorescence and O production independently of the Ag core size, but in a more pronounced way for larger Ag cores. These enhancements result from the increase in the PpIX excitation rate through the LSPR excitation and decrease when the distance between PpIX and Ag NPs increases. A maximum fluorescence enhancement of up to 14-fold, together with an increase in photogenerated O production of up to five times are obtained using 100 nm Ag cores coated with a 5 nm thick silica coating.
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