Rational Design of Biomaterials to Potentiate Cancer Thermal Therapy.

Cancer thermal therapy, also known as hyperthermia therapy, has long been exploited to eradicate mass lesions that are now defined as cancer. With the development of corresponding technologies and equipment, local hyperthermia therapies such as radiofrequency ablation, microwave ablation, and high-intensity focused ultrasound, have has been validated to effectively ablate tumors in modern clinical practice. However, they still face many shortcomings, including nonspecific damages to adjacent normal tissues and incomplete ablation particularly for large tumors, restricting their wide clinical usage. Attributed to their versatile physiochemical properties, biomaterials have been specially designed to potentiate local hyperthermia treatments according to their unique working principles. Meanwhile, biomaterial-based delivery systems are able to bridge hyperthermia therapies with other types of treatment strategies such as chemotherapy, radiotherapy and immunotherapy. Therefore, in this review, we discuss recent progress in the development of functional biomaterials to reinforce local hyperthermia by functioning as thermal sensitizers to endow more efficient tumor-localized thermal ablation and/or as delivery vehicles to synergize with other therapeutic modalities for combined cancer treatments. Thereafter, we provide a critical perspective on the further development of biomaterial-assisted local hyperthermia toward clinical applications.

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.

Surfactant-stripped J-aggregates of azaBODIPY derivatives: All-in-one phototheranostics in the second near infrared window.

Development of multifacted phototheranostics with bright fluorescence and absorbance in the second near infrared (NIR-II) window is very appealing for precise cancer diagnosis and treatment, but still challenging nowadays. Herein, we synthesize a hydrophobic annularly fused azaBODIPY (termed as HBP) molecule with sharp NIR absorbance peaked at 878 nm and bright NIR-II fluorescence. With Pluronic F127 as the surfactant and hydrophobic paclitaxel (PTX) as the spacer, such HBP molecule would self-assemble to form surfactant-stripped HBP/PTX micelles with absorption peak red-shifted to 1012 nm and intrinsic NIR-II fluorescence negligibly disturbed. We found that such HBP/PTX micelles can be utilized as a bimodal NIR-II nano-probe to enable real-time tracking of lymph nodes and tumors under an NIR-II fluorescence imaging system, as well as clear visualization of tumor microvasculatures under an NIR-II photoacoustic imaging system. Furthermore, together with 1064 nm laser exposure, such HBP/PTX micelles would synergistically suppress the growth of tumors grown on the mice upon tumor accumulation. This work highlights the concise preparation of a type of all-in-one NIR-II phototheranostics from the newly synthesized HBP molecules, thereby enables NIR-II fluorescence/photoacoustic bimodal imaging guided synergistic cancer treatment via the NIR-II laser boosted photothermal therapy and chemotherapy.