Biomaterial-assisted photoimmunotherapy for cancer.

With the development of phototherapy, which is a type of light-induced cancer treatment, various biomaterials have been well designed as photoabsorbing/sensitizing agents or effective carriers to enhance the therapeutic efficacy and evade the side effects of phototherapy. In recent years, the immunological responses induced by phototherapy have been widely explored, which are mainly triggered by the tumor associated antigens (TAAs) released from the dying cancer cells after phototherapy, together with the secretion of damage associated molecular patterns (DAMPs) and various pro-inflammatory cytokines/factors. To amplify these immunological responses induced by phototherapy, various adjuvant nano/micromaterials are introduced to boost the immune system to recognize and kill cancer cells. Moreover, such immune responses are further demonstrated to work in synergy with other immunotherapies such as immune checkpoint blockade (ICB), chimeric antigen receptor (CAR)-T cell and cytokine therapy, achieving significantly increased immune response rates and successful therapeutic outcomes. Here, this minireview will focus on the recent progress in engineering biomaterials for enhanced photoimmunotherapy and discuss the challenges, opportunities and future prospects in this field.

Near-infrared light and glucose dual-responsive cascading hydroxyl radical generation for in situ gelation and effective breast cancer treatment.

A general therapeutic strategy to treat breast cancer is attractive as different subtypes of breast cancers often exhibit distinct response to existing cancer therapeutics. To this end, we prepare a catalyst couple of glucose oxidase (GOx) and gallic acid-ferrous (GA-Fe) nanocomplexes, a type of near-infrared (NIR) absorbing Fenton catalyst, to enable NIR-trigger in-situ gelation and enhanced chemodynamic/starvation therapy that appears to be effective for different types of breast cancer cells. In this system, GOx is mixed with GA-Fe in a solution of N,N-dimethylacrylamide (DMAA) and poly (ethylene glycol) double acrylate (PEGDA). Upon intratumoral injection and NIR laser exposure, such GA-Fe show rapid temperature increase, which would simultaneously increase the catalytic efficiencies of GA-Fe and GOx. The cascade production of hydroxyl radicals (•OH) from glucose is then initiated to enable polymerization of DMAA and PEGDA to form a hydrogel at the injection site within the tumor. The continuous production of cytotoxic •OH together with glucose depletion by the intratumorally fixed catalyst couple would further confer effective destruction of breast cancer tumors by such chemodynamic/starvation therapy. Our work presents a hydrogel-based therapeutic strategy for local treatment of solid tumors with high tumor destruction efficacy and low systemic toxicity.

Local biomaterials-assisted cancer immunotherapy to trigger systemic antitumor responses.

Cancer immunotherapy by educating or stimulating patients' own immune systems to attack cancer cells has demonstrated promising therapeutic responses in the clinic. However, although the number of approved immunotherapeutics is rapidly increasing, key challenges such as limited clinical response rate and significant autoimmunity-related adverse effects remain to be resolved. Recently, it has been discovered that a diverse range of biomaterials-assisted local treatment methods including localized radiotherapy, chemotherapy or phototherapy are able to stimulate the immune systems, often by inducing immunogenic cell death (ICD). The triggered tumor-specific immunological responses after such local treatments, especially in combination with immune checkpoint blockade (ICB) therapy, can achieve a significant abscopal effect to attack whole-body spreading metastatic cancer cells, and later on result in immune memory to inhibit tumor recurrence. Moreover, local delivery of immunomodulatory therapeutics with biomaterials has also been demonstrated to be an alternative strategy to improve the therapeutic responses and reduce side effects of cancer immunotherapy. In this review, we would like to summarize the latest advances, challenges and opportunities in utilizing biomaterials-assisted local treatment strategies for enhancing anticancer immunity, and discuss further prospects in this field together with how this strategy may possibly be translated into clinical use.