Biomacromolecule-based photo-thermal agents for tumor treatment

Chitosan- and hyaluronic acid-based nanoarchitectures in phototherapy: Combination cancer chemotherapy, immunotherapy and gene therapy

Cancer phototherapy has been introduced as a new potential modality for tumor suppression. However, the efficacy of phototherapy has been limited due to a lack of targeted delivery of photosensitizers. Therefore, the application of biocompatible and multifunctional nanoparticles in phototherapy is appreciated. Chitosan (CS) as a cationic polymer and hyaluronic acid (HA) as a CD44-targeting agent are two widely utilized polymers in nanoparticle synthesis and functionalization. The current review focuses on the application of HA and CS nanostructures in cancer phototherapy. These nanocarriers can be used in phototherapy to induce hyperthermia and singlet oxygen generation for tumor ablation. CS and HA can be used for the synthesis of nanostructures, or they can functionalize other kinds of nanostructures used for phototherapy, such as gold nanorods. The HA and CS nanostructures can combine chemotherapy or immunotherapy with phototherapy to augment tumor suppression. Moreover, the CS nanostructures can be functionalized with HA for specific cancer phototherapy. The CS and HA nanostructures promote the cellular uptake of genes and photosensitizers to facilitate gene therapy and phototherapy. Such nanostructures specifically stimulate phototherapy at the tumor site, with particle toxic impacts on normal cells. Moreover, CS and HA nanostructures demonstrate high biocompatibility for further clinical applications.

Enhancing Cartilage Metabolism in Rats through a Novel Thermal Stimulation Technique with Photosensitizers

Although the moderate thermal stimulation of articular cartilage exerts chondroprotective effects, it is difficult to effectively heat deep articular cartilage with conventional methods. Photosensitizers increase the ambient temperature using near-infrared (NIR) radiation, which has high tissue permeability. We hypothesized that the intra-articular administration of photosensitizers and NIR irradiation would exert a greater heating effect on articular cartilage. We aimed to evaluate the heating effect of this method on cultured chondrocytes and rat knee cartilage. In vitro, we irradiated a photosensitizer-containing medium with NIR and measured changes in the medium temperature, cytotoxicity, and gene expression of heat shock protein (HSP) 70 and aggrecan (ACAN). In vivo, the knee joints of rats treated with photosensitizers were irradiated with NIR, and changes in intra-articular temperature and gene expression were measured, alongside histological analysis. The results showed that the medium and intra-articular temperature were raised to approximately 40 °C with no apparent disruption to articular cartilage or the immunohistochemically enhanced staining of HSP70 in chondrocytes. The gene expression of HSP70 and ACAN was increased in both cultured and articular cartilage. In summary, this method can safely heat joints and enhance cartilage metabolism by inducing HSP70 expression in articular cartilage. It presents a new hyperthermia therapy with effective cartilage protection.

Research progress of organic photothermal agents delivery and synergistic therapy systems

Cancer is currently one of the leading causes of mortality worldwide. Due to the inevitable shortcomings of conventional treatments, photothermal therapy (PTT) has attracted great attention as an emerging and non-invasive cancer treatment method. Photothermal agents (PTAs) is a necessary component of PTT to play its role. It accumulates at the tumor site through appropriate methods and converts the absorbed light energy into heat energy effectively under near-infrared light irradiation, thus increasing the temperature of the tumor area and facilitating ablation of the tumor cells. Compared to inorganic photothermal agents, which have limitations such as non-degradability and potential long-term toxicity in vivo, organic photothermal agents exhibit excellent biocompatibility and biodegradability, thus showing promising prospects for the application of PTT in cancer treatment. And these organic photothermal agents can also be engineered into nanoparticles to improve their water solubility, extend their circulation time in vivo, and specifically target tumors. Moreover, further combination of PTT with other treatment methods can effectively enhance the efficacy of cancer treatment and alleviate the side effects associated with single treatments. This article briefly introduces several common types of organic photothermal agents and their nanoparticles, and reviews the applications of PTT based on organic photothermal agents in combination with chemotherapy, photodynamic therapy, chemodynamic therapy, immunotherapy, and multimodal combination therapy for tumor treatment, which expands the ideas and methods in the field of tumor treatment.

Photo-Controllable Smart Hydrogels for Biomedical Application: A Review

Nowadays, smart hydrogels are being widely studied by researchers because of their advantages such as simple preparation, stable performance, response to external stimuli, and easy control of response behavior. Photo-controllable smart hydrogels (PCHs) are a class of responsive hydrogels whose physical and chemical properties can be changed when stimulated by light at specific wavelengths. Since the light source is safe, clean, simple to operate, and easy to control, PCHs have broad application prospects in the biomedical field. Therefore, this review timely summarizes the latest progress in the PCHs field, with an emphasis on the design principles of typical PCHs and their multiple biomedical applications in tissue regeneration, tumor therapy, antibacterial therapy, diseases diagnosis and monitoring, etc. Meanwhile, the challenges and perspectives of widespread practical implementation of PCHs are presented in biomedical applications. This study hopes that PCHs will flourish in the biomedical field and this review will provide useful information for interested researchers.

Multiscale photoacoustic tomography using reversibly switchable thermochromics

SIGNIFICANCE

Based on acoustic detection of optical absorption, photoacoustic tomography (PAT) allows functional and molecular imaging beyond the optical diffusion limit with high spatial resolution. However, multispectral functional and molecular PAT is often limited by decreased spectroscopic accuracy and reduced detection sensitivity in deep tissues, mainly due to wavelength-dependent optical attenuation and inaccurate acoustic inversion.

AIM

Previous work has demonstrated that reversible color-shifting can drastically improve the detection sensitivity of PAT by suppressing nonswitching background signals. We aim to develop a new color switching-based PAT method using reversibly switchable thermochromics (ReST).

APPROACH

We developed a family of ReST with excellent water dispersion, biostability, and temperature-controlled color changes by surface modification of commercial thermochromic microcapsules with the hydrophilic polysaccharide alginate.

RESULTS

The optical absorbance of the ReST was switched on and off repeatedly by modulating the surrounding temperature, allowing differential photoacoustic detection that effectively suppressed the nonswitching background signal and substantially improved image contrast and detection sensitivity. We demonstrate reversible thermal-switching imaging of ReST in vitro and in vivo using three PAT modes at different length scales.

CONCLUSIONS

ReST-enabled PAT is a promising technology for high-sensitivity deep tissue imaging of molecular activity in temperature-related biomedical applications, such as cancer thermotherapy.

Recent Development of Rhenium-Based Materials in the Application of Diagnosis and Tumor Therapy

Rhenium (Re) is widely used in the diagnosis and treatment of cancer due to its unique physical and chemical properties. Re has more valence electrons in its outer shell, allowing it to exist in a variety of oxidation states and to form different geometric configurations with many different ligands. The luminescence properties, lipophilicity, and cytotoxicity of complexes can be adjusted by changing the ligand of Re. This article mainly reviews the development of radionuclide 188Re in radiotherapy and some innovative applications of Re as well as the different therapeutic approaches and imaging techniques used in cancer therapy. In addition, the current application and future challenges and opportunities of Re are also discussed.

Liquid exfoliation of ultrasmall zirconium carbide nanodots as a noninflammatory photothermal agent in the treatment of glioma

Photothermal therapy (PTT), like other clinical translational tumor ablation techniques, requires a temperature increase above 50 °C to cause necrosis and death of tumor cells. Although the tumor can be eliminated rapidly by PTT, the inflammatory response is triggered by the large amounts of released reactive oxygen species (ROS). Therefore, liquid exfoliation was used to create ultrasmall zirconium carbide nanodots (NDs) with an average diameter of approximately 4.5 nm as noninflammatory/anti-inflammatory photosensitizers for PTT of glioma. Ultrasmall ZrC NDs showed excellent photothermal stability and biocompatibility but no obvious toxicity. Moreover, the ultrasmall ZrC NDs effectively ablated glioma at relatively low concentrations and inhibited tumor migration and proliferation in vitro and in vivo. Furthermore, the excellent ROS-scavenging ability of ultrasmall ZrC NDs suppressed the inflammatory response to PTT. Intriguingly, we found that ZrC had the capability of performing CT imaging. We demonstrated that the ultrasmall ZrC NDs created in this study could effectively and safely treat glioma without inflammation.

Aspects of Antiviral Strategies Based on Different Phototherapy Approaches: Hit by the Light

The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) which caused the COVID-19 pandemic spreading around the world from late 2019, served as a ruthless reminder of the threat viruses pose to global public health. The synthesis of new antiviral drugs, as well as repurposing existing products, is a long-term ongoing process which has challenged the scientific community. One solution could be an effective, accessible, and rapidly available antiviral treatment based on phototherapy (PT). PT has been used to treat several diseases, and relies on the absorption of light by endogenous molecules or exogenous photosensitizers (PS). PT has often been used in cancer treatment and prophylaxis, and as a complement to established chemotherapy and immunotherapy in combined therapeutic strategy. Besides significant applications in anticancer treatment, studies have demonstrated the beneficial impact of PT on respiratory, systemic, emerging, and oncogenic viral infections. The aim of this review was to highlight the potential of PT to combat viral infections by summarizing current progress in photodynamic, photothermal, and photoacoustic approaches. Attention is drawn to the virucidal effect of PT on systemic viruses such as the human immunodeficiency virus and human herpes viruses, including the causative agent of Kaposi sarcoma, human herpes virus (HHV8). PT has good potential for disinfection in anti-norovirus research and against pandemic viruses like SARS-CoV-2.

Biocompatible Inorganic Nanoagent for Efficient Synergistic Tumor Treatment with Augmented Antitumor Immunity

Synergistic therapy for malignant tumors has been developed in the past. However, several disadvantages that are associated with the applied inorganic nanoagents cannot be avoided, including intrinsic systemic toxicity, immunosuppression, and low therapeutic efficiency. Herein, a biocompatible, multifunctional, inorganic nanoagent that simultaneously integrates chemodynamic, starvation, and photothermal therapies is developed. This nanoagent effectively converts endogenous H₂ O₂ into highly toxic hydroxyl radicals via the Fenton reaction. Self-reinforced cancer therapy is achieved via the scavenging of intracellular glutathione and glucose. The encapsulation of nanoagent by erythrocytes drastically reduces its immune recognition by macrophages. Thus, an augmented anti-tumor immune response is realized. Moreover, in contrast to traditional inorganic chemodynamic nanomaterials, the nanoagent has outstanding photothermal efficiency. Therefore, the present system exhibits an effective tumor therapeutic outcome. This work may facilitate a new pathway for the development of highly efficacious synergetic therapies.