Shajesh Palantavida

Photoacoustic imaging (PAI) has emerged as a promising noninvasive biomedical imaging modality with high spatial resolution and soft tissue contrast. Exogenous contrast agents play a crucial role in enhancing the sensitivity and specificity of PAI. Among these contrast agents, the rare earth materials (REM) have garnered a lot of interest due to their near-infrared (NIR) absorption properties. REM established itself as a well-known entity in the field of bioimaging and therapy due to their optical, magnetic, and photothermal characteristics. The photoacoustic phenomenon of REM has the potential to emerge as a promising feature alongside its existing properties. The integration of the various REM as PAI exogenous contrast agents offers the potential for targeted imaging of specific biological structures or pathological conditions. In the present study, mechanisms behind the generation of acoustic signals are elucidated in detail, providing insights into the underlying principles of acoustic enhancements, in relation to the properties of contrast agents. The integration of rare earth contrast agents in various studies is highlighted, showcasing their potential for acoustic detection, multimodal imaging, and therapy. This review provides a comprehensive overview of recent advancements in utilizing rare earth contrast agents for enhancing PAI.

Utilization of bio-waste in environmental remediation can be a sustainable model for improving the effectiveness of cleanup efforts. Here, we have successfully investigated the phase evolution of an adsorbent material derived from Bivalvia shells via thermal treatment and implemented it for waste water remediation using a model dye. The structural investigation unveiled a polymorphic and compositional transformation of aragonite (85.8%)/calcite (14.2%) to calcite (100%), and aragonite (5.5%)/calcite (18.5%)/calcium hydroxide Ca(OH)2 (76.0%) upon thermal treatment at 300 °C (WP-3), 600 °C (WP-6), and 900 °C (WP-9), respectively. The electron microscopic images showed a beautiful sea urchin-like morphology after heating at 900 °C and with a surface area of 3.95 m2/g via BET analysis. The remediation studies showed maximum adsorption capacities of 170.11 mg/g and 183.98 mg/g calculated using the Sips and Langmuir isotherm models, respectively, for the WP-9 material. A mechanistic model for the interaction of the WP material and Congo red dye during adsorption is also presented from DFT studies. The study also show that the WP-9 material can act as a dye-sensitized photocatalyst to efficiently degrade the Congo red dye. Quantitively, 250 mg/L WP-9 degraded 98.24% of CR dye at a rate of 0.09192 min−1, which is almost twice that of commercial Degussa P25 under sunlight. The products of degradation were also studied using gas chromatography.

FRET enhancement in the plasmonic field is used to create photothermal agents that ratiometrically sense temperature.

A new temperature reporting, fluorescent photothermal agent with cancer targeting ability based on gold nanorods.

Ultrabright fluorescent nanothermometers – nanoparticles – allow measurement of temperature using single nanoparticles and 3D mapping of temperature distribution.