Increased extracellular Ca 2+ concentrations ([Ca 2+ ] ex) trigger activation of the NLRP3 inflammasome in monocytes through calcium-sensing receptor (CaSR). To prevent extraosseous calcification in vivo, the serum protein fetuin-A stabilizes calcium and phosphate into 70-100 nm-sized colloidal calciprotein particles (CPPs). Here we show that monocytes engulf CPPs via macropinocytosis, and this process is strictly dependent on CaSR signaling triggered by increases in [Ca 2+ ] ex. Enhanced macropinocytosis of CPPs results in increased lysosomal activity, NLRP3 inflammasome activation, and IL-1β release. Monocytes in the context of rheumatoid arthritis (RA) exhibit increased CPP uptake and IL-1β release in response to CaSR signaling. CaSR expression in these monocytes and local [Ca 2+ ] in afflicted joints are increased, probably contributing to this enhanced response. We propose that CaSR-mediated NLRP3 inflammasome activation contributes to inflammatory arthritis and systemic inflammation not only in RA, but possibly also in other inflammatory conditions. Inhibition of CaSRmediated CPP uptake might be a therapeutic approach to treating RA.

Amphiphilic gradient copolymers with thermoresponsive properties were synthesized in one pot via RAFT copolymerization.

Poly­(N-isopropylacrylamide) (PNiPAm) and poly­(2-ethyl-2-oxazoline) (PEtOx) represent two polymer types that are well-known for their lower critical solution temperature (LCST) behavior in aqueous media. To synthesize triblock copolymers containing both polymers, a crossover of two different polymerization methods was applied using a bifunctional initiator for the living cationic ring-opening polymerization (CROP) of EtOx. Quantitative end-functionalization with a trithiocarbonate resulted in a bifunctional PEtOx macro chain transfer agent (CTA). A series of well-defined PNiPAm-b-PEtOx-b-PNiPAm triblock copolymers were obtained by subsequent reversible addition–fragmentation chain transfer (RAFT) polymerization of NiPAm. The influence of the PNiPAm to PEtOx ratio on the thermoresponsive properties was intensively investigated via turbidimetry, dynamic light scattering, cryo transmission electron microscopy, and 1H NMR studies, revealing hydrogen bonds between both copolymer segments that strongly lower the phase separation temperature of aqueous solutions.

In order to obtain a novel, pH responsive polymersome system, a series of pH responsive block copolymers were synthesized via the reversible addition-fragmentation chain transfer (RAFT) polymerization of 3,4-dihydro-2H-pyran (DHP) protected 2-hydroxyethyl methacrylate (HEMA) (2-((tetrahydro-2H-pyran-2-yl)oxy)ethyl methacrylate (THP-HEMA)) and 2-(dimethylamino) ethyl methacrylate (DMAEMA) using p(THP-HEMA) as a macro chain transfer agent (mCTA). The degree of polymerization (DP) of the p(THP-HEMA) block was fixed to 35, whereas the DP of the p(DMAEMA) block was systematically varied from 21 to 50. In aqueous solution, the block copolymer with the shortest p(DMAEMA) block (DP = 21) self-assembled into vesicles, while the polymer with 30 units of p(DMAEMA) formed a mixture of micelles and vesicles. The polymer with the longest p(DMAEMA) block (DP = 50) formed exclusively micelles. The corresponding polymersomes exhibited a morphology transition from vesicles at neutral pH values to micelles upon lowering the pH value down to endosomal pH value as investigated by DLS and cryo-TEM. The capability of polymersomes to encapsulate both hydrophobic (e.g., Nile Red) and hydrophilic (e.g., doxorubicin hydrochloride (DOX·HCl)) cargos was verified by in vitro studies. Drug release studies demonstrated that the DOX·HCl release is significantly accelerated under acidic pH values compared to physiological conditions. Cytotoxicity studies revealed that DOX·HCl loaded polymersomes exhibited an efficient cell death comparable to free DOX·HCl. CLSM and flow cytometry studies showed that DOX·HCl loaded vesicles were easily taken up by L929 cells and were mainly located in the cytoplasm and cell nuclei.

Nanoparticles with light-to-heat conversion properties play vital roles in the design of photothermal materials that can be remotely heated via light activation. Halloysite nanotubes (HNTs), versatile natural clay nanoparticles, were converted into efficient photothermal agents by functionalizing them with polydopamine, a polymer with light-to-heat conversion properties. By varying the polydopamine functionalization reaction conditions such as dopamine concentration, reaction time, and the nature of the HNTs, HNT-polydopamine (HNT-PDA) nanohybrids comprising different amounts of polydopamine were obtained. HNT-PDA nanohybrids presented significant temperature elevations when irradiated with 808 nm laser light, reaching 250 °C in 2 min, and were demonstrated to be effective photothermal agents, whose light-to-heat conversion properties and the degree of lightactivated temperature elevations can be easily tuned by controlling the polydopamine content through reaction conditions. The photothermal effect of HNT-PDA nanohybrids was demonstrated to be stable over multiple laser light-activation cycles, allowing their reusability. In addition to infrared laser light activation, HNT-PDA nanohybrids were also shown to be activated by other light sources of more practical importance such as a solar simulator, an infrared incandescent lamp, and a light-emitting diode (LED) lamp, demonstrating their versatility as photothermal agents. As one of the potential applications of HNT-PDA nanohybrids, their light-activated antibacterial activity was evaluated. The viability of Staphylococcus aureus (S. aureus) treated with HNT-PDA nanohybrids was reduced by 6.3 log when irradiated with infrared laser light for 5 min, whereas bacteria not treated with the nanohybrids stayed alive under the same irradiation conditions. Comprising natural, nontoxic, cost-effective components, HNT-PDA nanohybrids are promising nanoparticles as versatile clay-based photothermal agents that can be utilized in various photo-driven applications.