Metallo-alginate hydrogel can potentiate microwave tumor ablation for synergistic cancer treatment.

Microwave ablation (MWA) as a local tumor ablation strategy suffers from posttreatment tumor recurrence. Development of adjuvant biomaterials to potentiate MWA is therefore of practical significance. Here, the high concentration of Ca2+ fixed by alginate as Ca2+-surplus alginate hydrogel shows enhanced heating efficiency and restricted heating zone under microwave exposure. The high concentration of extracellular Ca2+ synergizes with mild hyperthermia to induce immunogenic cell death by disrupting intracellular Ca2+ homeostasis. Resultantly, Ca2+-surplus alginate hydrogel plus MWA can ablate different tumors on both mice and rabbits at reduced operation powers. This treatment can also elicit antitumor immunity, especially if synergized with Mn2+, an activator of the stimulation of interferon genes pathway, to suppress the growth of both untreated distant tumors and rechallenged tumors. This work highlights that in situ-formed metallo-alginate hydrogel could act as microwave-susceptible and immunostimulatory biomaterial to reinforce the MWA therapy, promising for clinical translation.

ATP-Responsive Smart Hydrogel Releasing Immune Adjuvant Synchronized with Repeated Chemotherapy or Radiotherapy to Boost Antitumor Immunity.

Certain chemotherapeutics and forms of ionizing radiation can induce immunogenic cell death (ICD). If there simultaneously exist immune adjuvants within the tumor, such antitumor immunity would be further amplified. However, as clinical chemo/radiotherapies are usually repeatedly given at low individual doses, it would be impractical to administrate immune adjuvants into tumors at each dose of chemo/radiotherapies. Thus, a smart hydrogel is developed that releases immune adjuvants in response to repeatedly applied chemo-/radiotherapies. Herein, alginate is conjugated with an adenosine triphosphate (ATP)-specific aptamer, which is hybridized with immunoadjuvant CpG oligonucleotide. Upon intratumoral injection, alginate-based hydrogel is formed in situ. Interestingly, low doses of oxaliplatin or X-rays, while inducing ICD of tumor cells, could trigger release of ATP, which competitively binds with ATP-specific aptamer to trigger CpG release. Therefore, the smart hydrogel could release the immune adjuvant synchronized with low-dose repeated chemo/radiotherapies, achieving remarkable synergistic responses in eliminating established tumors, as well as immune memory to reject re-challenged tumors. Moreover, repeated radiotherapies assisted by the smart hydrogel could inhibit distant tumor metastases, especially in combination with immune checkpoint blockade. The study presents a conceptually new strategy to boost cancer immunotherapy coherent with repeated low-dose chemo-/radiotherapies following a clinically relevant manner.

Bimetallic Oxide MnMoOX Nanorods for in Vivo Photoacoustic Imaging of GSH and Tumor-Specific Photothermal Therapy.

Accurate imaging of glutathione (GSH) in vivo is able to provide real-time visualization of physiological and pathological conditions. Herein, we successfully synthesize bimetallic oxide MnMoOX nanorods as an intelligent nanoprobe for in vivo GSH detection via photoacoustic (PA) imaging. The obtained MnMoOX nanoprobe with no near-infrared (NIR) absorption in the absence of GSH would exhibit strong GSH-responsive NIR absorbance, endowing PA imaging detection of GSH. Due to the up-regulated GSH concentration in the tumor microenvironment, our MnMoOX nanoprobe could be utilized for in vivo tumor-specific PA imaging. Moreover, MnMoOX nanorods with GSH-responsive NIR absorbance could also be employed to achieve tumor-specific photothermal therapy (PTT). Importantly, such MnMoOX nanorods show inherent biodegradability and could be rapidly cleared out from the body, minimizing their long-term body retention and potential toxicity. Our work presents a new type of GSH-responsive nanoprobe based on bimetallic oxide nanostructures, promising for tumor-specific imaging and therapy.

Equilibrium, kinetic and thermodynamic studies of uranium biosorption by calcium alginate beads.

Calcium alginate beads are potential biosorbent for radionuclides removal as they contain carboxyl groups. However, until now limited information is available concerning the uptake behavior of uranium by this polymer gel, especially when sorption equilibrium, kinetics and thermodynamics are concerned. In present work, batch experiments were carried out to study the equilibrium, kinetics and thermodynamics of uranium sorption by calcium alginate beads. The effects of initial solution pH, sorbent amount, initial uranium concentration and temperature on uranium sorption were also investigated. The determined optimal conditions were: initial solution pH of 3.0, added sorbent amount of 40 mg, and uranium sorption capacity increased with increasing initial uranium concentration and temperature. Equilibrium data obtained under different temperatures were fitted better with Langmuir model than Freundlich model, uranium sorption was dominated by a monolayer way. The kinetic data can be well depicted by the pseudo-second-order kinetic model. The activation energy derived from Arrhenius equation was 30.0 kJ/mol and the sorption process had a chemical nature. Thermodynamic constants such as ΔH(0), ΔS(0) and ΔG(0) were also evaluated, results of thermodynamic study showed that the sorption process was endothermic and spontaneous.

Biosorption of uranium by magnetically modified Rhodotorula glutinis.

Adsorption of uranium from aqueous solution onto the magnetically modified yeast cell, Rhodotorula glutinis, was investigated in a batch system. Factors influencing sorption such as initial solution pH, biomass dosage, contact time, temperature, initial uranium concentration and other common cations were analyzed. Sorption isotherm, kinetic and thermodynamic studies of uranium on magnetically modified R. glutinis were also carried out. The temperature dependent equilibrium data agreed well with the Langmuir model. Kinetic data obtained at different temperatures were simulated using pseudo-first-order and pseudo-second-order kinetic models, the pseudo-second-order kinetic model was found to describe the data better with correlation coefficients near 1.0. The thermodynamic parameters, ΔH°, ΔS° and ΔG° were calculated from the sorption data gained at different temperatures. These thermodynamic parameters showed that the sorption process was endothermic and spontaneous. All results indicated that magnetically modified R. glutinis can be a potential sorbent for uranium wastewater treatment.