Siwen Li

Photodynamic therapy (PDT) combined with oxygenating strategies is widely employed in cancer treatment; however, oxygen-boosted PDT has failed to achieve an ideal effect due to the complexity, heterogeneity, and irreversible hypoxic environment generated by tumor tissues. With the emergence of Fe-dependent ferroptosis boasting reactive oxygen species (ROS) cytotoxicity as well, such a chemodynamic approach to cancer therapy has drawn extensive attention. In this study, hemoglobin (Hb) is connected with the photosensitizer chlorin e6 (Ce6) to construct a 2-in-1 nanoplatform (SRF@Hb-Ce6) with Sorafenib (SRF, ferroptosis promotor) loaded, combining oxygen-boosted PDT and potent ferroptosis. Benefiting from the intrinsic presence of Fe capable of binding oxygen, hemoglobin concurrently furnishes oxygen for oxygen-dependent PDT and Fe for Fe-dependent ferroptosis. Furthermore, amphiphilic MMP2-responsive peptide is incorporated into the skeleton of the nanoplatform to ensure drug-release specificity for safety improvement. Correlative measurements demonstrate the potentiation of PDT and ferroptosis with SRF@Hb-Ce6. More importantly, PDT strengthens ferroptosis by recruiting immune cells to secrete IFN-γ, which can sensitize the tumor to ferroptosis in our findings. The therapeutic effect of synergistic treatment with SRF@Hb-Ce6 in vitro and in vivo was proven significant, revealing the promising prospects of combined PDT and ferroptosis therapy with the 2-in-1 nanoplatform.

The electrical conductivity, Seebeck coefficient and thermal conductivity of oxide Ca 9 Co 12 O 28 with Ca 2 Co 2 O 5 -type structure are 84 S cm –1 , 118 µV K –1 and 1.73 W m –1 K –1 respectively at 700 °C, and its figure of merit is 0.67×10 –4 K –1 , showing that Ca 9 Co 12 O 28 is a potential material for high temperature thermoelectric energy conversion.

The resistance of cancer cells to photothermal therapy is closely related to the overexpression of heat shock proteins (HSPs), which are abnormally upregulated when cells are under lethal stresses. Common strategies that use small molecule inhibitors against HSPs to enhance hyperthermia effect lack spatial and temporal control of drug release, leading to unavoidable systemic toxicity. Herein, a versatile photothermal platform is developed which is composed of a hollow gold nanoshell core densely packed with small interfering RNAs against heat shock protein 70 (Hsp70). Upon near infrared light irradiation, the small interfering RNAs can detach from gold surface specifically and escape from endosomes for Hsp70 silencing. Meanwhile, the temperature increases for hyperthermia therapy due to the high photothermal efficiency of the nanoshells. Efficient downregulation of Hsp70 after light activation is achieved in vitro and in vivo. Ultimately, the light-controlled dual functional nanosystem, with the effects of Hsp70 silencing and temperature elevation, results in sensitized photothermal therapy in nude mice model under mild temperature. This strategy smartly combines the localized photothermal therapy with controlled Hsp70 silencing, and has great potential for clinical translation with a simple and easily controlled structure.

Abstract Two-dimensional (2D) magnetism has been long sought-after and only very recently realized in atomic crystals of magnetic van der Waals materials. So far, a comprehensive understanding of the magnetic excitations in such 2D magnets remains missing. Here we report polarized micro-Raman spectroscopy studies on a 2D honeycomb ferromagnet CrI 3 . We show the definitive evidence of two sets of zero-momentum spin waves at frequencies of 2.28 terahertz (THz) and 3.75 THz, respectively, that are three orders of magnitude higher than those of conventional ferromagnets. By tracking the thickness dependence of both spin waves, we reveal that both are surface spin waves with lifetimes an order of magnitude longer than their temporal periods. Our results of two branches of high-frequency, long-lived surface spin waves in 2D CrI 3 demonstrate intriguing spin dynamics and intricate interplay with fluctuations in the 2D limit, thus opening up opportunities for ultrafast spintronics incorporating 2D magnets.

Photodynamic therapy (PDT) has recently been proposed as an innovative approach to combat multi-drug resistant (MDR) bacteria. To improve the penetration depth of current PDT, a core–shell upconversion nanoparticle (UCNP) based PDT system, composed of a cationic N-octyl chitosan (OC) coated UCNP loaded with the photosensitizer zinc phthalocyanine (OC-UCNP-ZnPc), was constructed to enhance the antibacterial efficacy against MDR bacteria in deep tissue. The core–shell UCNPs displayed a higher upconversion fluorescence efficiency compared to the inner UCNP core. Dual antibacterial activities induced by chitosan and PDT-induced ROS were demonstrated, independent of the bacterial species. In particular, these nanoconstructs exhibited excellent antibacterial effects on the MDR bacteria including methicillin-resistant Staphylococcus aureus (MRSA) and β-lactamase-producing Escherichia coli. In vivo antibacterial therapy for murine MRSA-infected abscesses in the deep tissue (1 cm) strongly confirmed the outstanding anti-MRSA efficacy of OC-UCNP-ZnPc. Our results indicated that the OC-UCNP-ZnPc based PDT system triggered by deep-penetrating NIR light has a prominent antibacterial effect on MDR bacteria, which could be a promising strategy for deep-tissue infections.