Barocaloric Effects in Dialkylammonium Halide Salts.

Barocaloric effects─solid-state thermal changes induced by the application and removal of hydrostatic pressure─offer the potential for energy-efficient heating and cooling without relying on volatile refrigerants. Here, we report that dialkylammonium halides─organic salts featuring bilayers of alkyl chains templated through hydrogen bonds to halide anions─display large, reversible, and tunable barocaloric effects near ambient temperature. The conformational flexibility and soft nature of the weakly confined hydrocarbons give rise to order-disorder phase transitions in the solid state that are associated with substantial entropy changes (>200 J kg K) and high sensitivity to pressure (>24 K kbar), the combination of which drives strong barocaloric effects at relatively low pressures.

Colossal barocaloric effects with ultralow hysteresis in two-dimensional metal-halide perovskites.

Pressure-induced thermal changes in solids-barocaloric effects-can be used to drive cooling cycles that offer a promising alternative to traditional vapor-compression technologies. Efficient barocaloric cooling requires materials that undergo reversible phase transitions with large entropy changes, high sensitivity to hydrostatic pressure, and minimal hysteresis, the combination of which has been challenging to achieve in existing barocaloric materials. Here, we report a new mechanism for achieving colossal barocaloric effects that leverages the large volume and conformational entropy changes of hydrocarbon order-disorder transitions within the organic bilayers of select two-dimensional metal-halide perovskites.

Ultracompact Nanotheranostic PEG Platform for Cancer Applications.

We present a new targetable nanoconstruct (NC) capable of simultaneously serving as a therapeutic platform for photodynamic therapy (PDT) as well as a magnetic resonance (MR) molecular imaging agent, free of heavy metal atoms. PDT has seen much interest with the introduction of NC-assisted cell-specific targeting of the photosensitizer (PS). The previously reported ultrasmall 8-arm polyethylene glycol amine (8PEGA) NC, with an attached chlorin e6 (Ce6) PS, yielded promising results for PDT of heart arrhythmia, and , on live rat and sheep hearts, respectively, when using targeting peptides for of cardio-myocytes.

Intracellular Photodynamic Activity of Chlorin e6 Containing Nanoparticles.

Nanoparticles (NPs) containing the photo-therapeutic dye (Ce6) have been explored in multiple studies for photo-dynamic therapy (PDT). However, little work has been carried out regarding their PDT efficacy, relative to other dye containing NPs. Here polyacrylamide nanoparticles (PAAm NPs) containing Ce6 were prepared and their PDT efficacy compared to previously reported methylene blue (MB) containing PAAmNPs.