Photoacoustic Imaging Endometriosis Lesions with Nanoparticulate Polydopamine as a Contrast Agent.

Endometriosis (EM) is a prevalent and debilitating gynecological disorder primarily affecting women of reproductive age. The diagnosis of EM is historically hampered by delays, owing to the absence of reliable diagnostic and monitoring techniques. Herein, it is reported that photoacoustic imaging can be a noninvasive modality for deep-seated EM by employing a hyaluronic-acid-modified polydopamine (PDA@HA) nanoparticle as the contrast agent. The PDA@HA nanoparticles exhibit inherent absorption and photothermal effects when exposed to near-infrared light, proficiently converting thermal energy into sound waves. Leveraging the targeting properties of HA, distinct photoacoustic signals emanating from the periphery of orthotopic EM lesions are observed. These findings are corroborated through anatomical observations and in vivo experiments involving mice with green fluorescent protein-labeled EM lesions. Moreover, the changes in photoacoustic intensity over a 24 h period reflect the dynamic evolution of PDA@HA nanoparticle biodistribution. Through the utilization of a photoacoustic ultrasound modality, in vivo assessments of EM lesion volumes are conducted. This innovative approach not only facilitates real-time monitoring of the therapeutic kinetics of candidate drugs but also obviates the need for the sacrifice of experimental mice. As such, this study presents a promising avenue for enhancing the diagnosis and drug-screening processes of EM.

Erbium oxide nanoplates as a sonosensitizer devoid of photosensitivity.

Phototoxicity is an undesirable consequence of photodynamic and most sonodynamic therapies. In the current work, we showed that Er2O3 nanoplates can avoid being cytotoxic when exposed to light and could be an effective sonosensitizer.

Ultrasmall Day-Night Photocatalysts of LnYVO4:Eu3+ (Ln = Nd, Tm, and Er) Nanoparticles.

Day-night photocatalysts that can persistently generate reactive oxygen species (ROS) after ceasing light attracted intensive attention in diverse fields. However, current strategies of combining a photocatalyst and an energy storage material can hardly fulfill the demands, especially in size. We herein present a one-phase sub-5 nm day-night photocatalyst via simply doping Nd, Tm, or Er into YVO4:Eu3+ nanoparticles, efficiently producing ROS in both day and night modes. We demonstrate that the rare earth ions acted as a ROS generator, and Eu3+ and defects contributed to the long persistency. Furthermore, the ultrasmall size led to remarkable bacterial uptake and bactericidal efficacy. Our finding suggests an alternative mechanism of day-night photocatalysts that could be ultrasmall and thus may shed light on disinfection and other applications.

Near-Infrared Light-Excited Reactive Oxygen Species Generation by Thulium Oxide Nanoparticles.

Exploring materials that can absorb near-infrared (NIR) light to produce reactive oxygen species (ROS) is necessary for many fields. Herein we show that thulium oxide nanoparticles are viable for NIR-stimulated ROS generation. This property may be related to the unique energy levels, large absorption cross section, low fluorescence emission, and ∼10-3 s lifetime of the 3H4 state of Tm ions. We further demonstrate the impact of these nanoparticles on photodynamic therapy (PDT), in which impressive tumor inhibition was recorded after exposure to either a broadband halogen lamp or an 808 nm laser. Our results may provide insight into the areas of photocatalysis, pollution treatment, and fine chemical synthesis.

Revisiting the factors influencing the magnetic resonance contrast of Gd2O3 nanoparticles.

Gadolinium oxide nanoparticles (GONs) have the potential to be one of the best candidates for the contrast agents of magnetic resonance imaging. Even though the influence of parameters on the relaxation has been substantially demonstrated, the variation of the r 1 of GONs with a similar structure and surface chemistry implied our limited understanding. We herein synthesized GONs with adjustable size, shape, and crystallinity, modified them with a series of molecules with different acidities, and recorded their r 1 values and imaging contrast. Our results showed that the isoelectric point could be regarded as an indicator of the relaxation covering the influence of both surface modification and size, which highlighted the impact of protons dissociated from the contrast agents. We further showed that the nanoparticles with lower crystallinity possess higher relaxivity, and this phenomenon manifested significantly under a low field. Our work clarified that the longitudinal relaxivity of Gd2O3 nanoparticles is sensitively dependent on the numbers of H+ generated from the surface and in the environment, which may shed light on developing high-performance nanoparticulate T 1 contrast agents.