Photothermal Therapy Agents Research Articles

S-Doped Hollow Multi-Metallic Prussian Blue Analogue (PBA) Nanoplatform for Enhanced Anticancer for Cervical Cancer.

Developing novel multimodal nanomaterials-based anticancer agents to meet complex clinical demands is an urgent challenge. This study presents a novel uniform hollow S-doped NiCuFe Prussian blue analogue (NiCuFe-S) with satisfactory size and properties as anticancer agents for efficient cervical cancer therapy using a simple and environmentally friendly procedure. The formation mechanism and the reason for enhanced performance of NiCuFe-S were characterized and discussed by diverse spectroscopic and microscopic methods. Moreover, to demonstrate the anti-cancer ability of NiCuFe-S, in vitro and in vivo experiments were carried out. Compared to the non-doped NiCuFe, the NiCuFe-S exhibited significantly enhanced photothermal and catalytic activity attributed to the electronic bandgap-narrowing effect and the increased electron circuit paths resulting from S doping. The hollow structure of NiCuFe-S facilitated the loading of small-molecule drugs, such as doxorubicin (DOX), transforming it into a multimodal nanoplatform for cervical cancer treatment. In vitro and in vivo experiments proved the potential of the NiCuFe-S nanotheranostic agent for chemodynamic therapy (CDT), photothermal therapy (PTT), and chemotherapy for cervical cancer. This research not only overcomes inherent limitations but also significantly broadens the applications of Prussian blue analogues in biomedicine.

Theranostic Phthalocyanine and Naphthalocyanine Nanoparticles for Photoacoustic Imaging and Photothermal Therapy of Tumors.

Background: Phthalocyanine (PC) and naphthalocyanine (NC) dyes have long garnered interest as theranostic agents for optical imaging and phototherapy due to their near-infrared absorbance, photostability, imaging contrast, and proven safety in clinical trials. Yet, only a small fraction of these dyes has been evaluated as photothermal therapy (PTT) agents for cancer treatment. Methods: Nearly 40 distinct NC and PC dyes were encapsulated within polymeric PEG-PCL micelles via oil-in-water emulsions. The optimal NC/PC-loaded micelle formulations for PTT and photoacoustic (PA) imaging were identified through in vivo and in vitro studies. Results: The most promising candidate, CuNC(Octa)-loaded micelles, demonstrated a strong PA signal with a peak absorbance at ~870 nm, high photothermal efficiency, and photostability. The CuNC(Octa)-loaded micelles exhibited heat generation as good or better than gold nanorods/nanoshells and >10-fold higher photoacoustic signals. Micelle preparation was reproducible/scalable, and the CuNC(Octa)-loaded micelles are highly stable under physiological conditions. The CuNC(Octa)-loaded micelles localize within tumors via enhanced permeability and retention and are readily detectable by PA imaging. In a syngeneic murine tumor model of triple-negative breast cancer, CuNC(Octa)-loaded micelles demonstrate efficient heat generation with PTT, leading to the complete eradication of tumors. Conclusions: CuNC(Octa)-loaded micelles represent a promising theranostic agent for PA imaging and PTT. The ability to utilize conventional ultrasound in combination with PA imaging enables the simultaneous acquisition of information about tumor morphology and micelle accumulation. PTT with CuNC(Octa)-loaded micelles can lead to the complete eradication of highly invasive tumors.

Liquid exfoliation of molybdenum metallenes for non-inflammatory photothermal therapy of tumors.

Tissue damage and cell death occurring during photothermal therapy (PTT) for tumors can induce an inflammatory response that is detrimental to tumor therapy. Herein, ultrathin Mo metallene nanosheets with a thickness of <5 nm prepared by liquid phase exfoliation were explored as functional hyperthermia agents for non-inflammatory ablation of tumors. The obtained Mo metallene nanosheets exhibited good photothermal conversion properties and significant reactive oxygen species (ROS) scavenging ability, thus achieving superior cancer cell ablation and anti-inflammatory effects in vitro. For in vivo experiments, 4T1 tumors were ablated while the inflammation-related cytokine levels did not obviously increase, demonstrating that the inflammatory response induced by PTT was inhibited by the anti-inflammatory properties of Mo metallene nanosheets. Moreover, Mo metallene nanosheets depicted good dispersibility and biocompatibility, beneficial for biomedical applications. This work introduces Mo metallenes as promising hyperthermia agents for non-inflammatory PTT of tumors.

Delivery of Cu(II) and Mn(II) by polydopamine-modified nanoparticles for combined photothermal and chemotherapy.

Chemodynamic therapy (CDT) has been recognized as an emerging therapeutic strategy. It has attracted considerable attention in recent years as it can generate the most harmful reactive oxygen species (ROS)-hydroxyl radicals (•OH) through the Fenton reaction or a Fenton-like reaction under the catalysis of versatile metal cations, such as, Fe(II), Fe(III), Cu(I), Mn(II), and Mn(III). However, a large number of reducing species (e.g., GSH) in tumors inhibit the therapeutic effects of CDT. This study proposes a nanocarrier strategy that can release versatile metal cations in the initial stage to consume the reducing substances, which can be convenient for subsequent CDT treatment. A novel nano-delivery system based on H-MnO2@PDA/Cu-CD@Ad-TK-Ad@Ploy-CD (abbreviated as MNZ) was proposed to resolve the above problems. Herein, hollow mesoporous manganese dioxide nanoparticles (H-MnO2) were coated with PDA and modified with copper ions on the surface of PDA. The PDA was then functionalized with β-cyclodextrin (β-CD) substitutions that were further assembled with N-((1S,3R,5S)-adamantan-1-yl)-3-((2-((3-(((3s,5s,7s)-adamantan-1-yl)amino)-3-oxopropyl)thio)propan-2-yl)thio)propenamide (Ad-TK-Ad). Poly-CD was assembled with CD to improve the stability of the reactor. The MNZ nanotheranostic platform can release Cu(II) and Mn(II), which could react with intracellular GSH to consume the reducing substances in tumors. Subsequently, H2O2 can be converted into •OH, and the effect is improved with increasing temperatures. Cytotoxicity of MNZ (200 μg mL-1) was studied by cell counting kit-8 (CCK-8) assay using HeLa cells as the models. Results indicated that cell viability was clearly reduced to 22% by the nanoparticles alone, to 18% by the nanoparticles with H2O2, and to 9% by the nanoparticles with H2O2 and NIR, under weak acidic condition (pH 6.8). This work provides a beneficial exploration for the application of nano-delivery strategies for combined photothermal and chemodynamic therapy agents.

Laser-synthesized plasmonic HfN-based nanoparticles as a novel multifunctional agent for photothermal therapy.

Hafnium nitride nanoparticles (HfN NPs) can offer appealing plasmonic properties at the nanoscale, but the fabrication of stable water-dispersible solutions of non-toxic HfN NPs exhibiting plasmonic features in the window of relative biological transparency presents a great challenge. Here, we demonstrate a solution to this problem by employing ultrashort (femtosecond) laser ablation from a HfN target in organic solutions, followed by a coating of the formed NPs with polyethylene glycol (PEG) and subsequent dispersion in water. We show that the fabricated NPs exhibit plasmonic absorption bands with maxima around 590 nm, 620 nm, and 650 nm, depending on the synthesis environment (ethanol, acetone, and acetonitrile, respectively), which are largely red-shifted compared to what is expected from pure HfN NPs. The observed shift is explained by including nitrogen-deficient hafnium nitride and hafnium oxynitride phases inside the core and oxynitride coating of NPs, as follows from a series of structural characterization studies. We then show that the NPs can provide a strong photothermal effect under 808 nm excitation with a photothermal conversion coefficient of about 62%, which is comparable to the best values reported for plasmonic NPs. MTT and clonogenic assays evidenced very low cytotoxicity of PEG-coated HfN NPs to cancer cells from different tissues up to 100 μg mL-1 concentrations. We finally report a strong photothermal therapeutic effect of HfN NPs, as shown by 100% cell death under 808 nm light irradiation at NP concentrations lower than 25 μg mL-1. Combined with additional X-ray theranostic functionalities (CT scan and photon capture therapy) profiting from the high atomic number (Z = 72) of Hf, plasmonic HfN NPs promise the development of synergetically enhanced modalities for cancer treatment.

An intelligent NIR-IIb-responsive lanthanide@metal-organic framework core-shell nanocatalyst for combined deep-tumor therapy.

The ground-breaking combination of photodynamic therapy (PDT) and photothermal therapy (PTT) has attracted much attention in medical fields as an effective method for fighting cancer. However, evidence suggests that the therapy efficiency is still limited by shallow light penetration depth and poor photosensitizer loading capacity. Herein, we constructed an upconversion nanoparticle@Zr-based metal-organic framework@indocyanine green molecule (UCNPs@ZrMOF@ICG) nanocomposite to integrate 1532 nm light-triggered PDT and 808 nm light-mediated PTT. NaLnF4 nanoparticles are designed to emit upconversion luminescence (UCL) under 1532 nm laser excitation, which is consistent with the absorption spectra of the ZrMOF. Benefiting from the excellent energy transfer efficiency, the ZrMOF can absorb visible light from the UCNPs and then catalyze O2 into 1O2 for deep tissue PDT. To achieve combination therapy, the clinically approved ICG nanocomposite was introduced as a photothermal agent for PTT under 808 nm laser irradiation, and the photothermal conversion efficiency was calculated to be ∼28%. The designed nanosystems facilitate efficient deep-tissue tumor treatment by integrating PDT with PTT. Ultimately, this study creates a multifunctional nanocomposite by combining 1532 nm light-triggered deep tissue PDT and near-infrared (NIR) light-driven PTT for personalized cancer therapy.

Monophenylboryl aza-BODIPY with free rotation of the B-phenyl group for enhanced photothermal conversion.

Owing to the efficient non-radiative relaxation by the free rotation of the B-phenyl moiety, monophenyl substituted aza-BODIPY on the boron centre with near-infrared absorption has high photothermal conversion efficiency, which is highly desirable for a photothermal therapy agent.

Recent Trends in Bio-nanomaterials and Non-invasive Combinatorial Approaches of Photothermal Therapy against Cancer.

In 2020, approximately 10 million deaths worldwide were attributed to cancer, making it the primary cause of death globally. Photothermal therapy (PTT) is one of the novel ways to treat and abolish cancer. PTT significantly impacts cancer theranostics compared to other therapies like surgery, chemotherapy, and radiotherapy due to its remarkable binding capability to tumor sites and lower invasiveness into normal healthy tissues. PTT relies on photothermal agents (PTAs), which generate heat by absorbing the near-infrared (NIR) light and destroying cancer cells. Several PTT agents remain longer in the reticuloendothelial system (RES) and induce toxicity, restricting their use in the biomedical field. To overcome this problem, the usage of biodegradable nano-photothermal agents is required. This review has discussed the PTT mechanism of action and different types of novel bio-nanomaterials used for PTT. We also focussed on the combinatorial effects of PTT with other cancer therapies and their effect on human health. The role of LED lights and mild hypothermia in PTT has been discussed briefly in this review.

Acceptor-donor-acceptor-type molecules with large electrostatic potential difference for effective NIR photothermal therapy.

Although acceptor-donor-acceptor (A-D-A)-type molecules offer advantages in constructing NIR absorbing photothermal agents (PTAs) due to their strong intramolecular charge transfer and molecular planarity, their applications in photothermal therapy (PTT) of tumors remain insufficiently explored. In particular, the influence of ESP distribution on the optical properties of A-D-A photosensitizers has not been investigated. Herein, we analyze and compare the difference in ESP distribution between A-D-A-type small molecules and polymers to construct NIR absorbing PTAs with a high extinction coefficient (ε) and high photothermal conversion efficiency (PCE). The calculation results of density functional theory (DFT) indicate that the large ESP difference makes A-D-A-type small molecules superior to their polymer counterparts in realizing tight molecular packing and strong NIR absorbance. Among the as-prepared nanoparticles (NPs), Y6 NPs exhibited an obvious bathochromic shift of absorption peak from 711 nm to 822 nm, with the NIR-II emission extended to 1400 nm. Moreover, a high ε value of 5.69 L g-1 cm-1 and a PCE of 66.3% were attained, making Y6 NPs suitable for PTT. With a concentration of 100 μg mL-1, Y6 NPs in aqueous dispersion yielded a death rate of 93.4% for 4T1 cells upon 808 nm laser irradiation (1 W cm-2) for 10 min, which is comparable with the best results of recently reported PTT agents.

A bismuth-based double-network hydrogel-mediated synergistic photothermal-chemodynamic therapy for accelerated wound healing.

Multidrug-resistant bacterial infections present a significant challenge to wound healing. Non-antibiotic approaches such as photothermal therapy (PTT) and chemodynamic therapy (CDT) are promising but have suboptimal anti-bacterial efficacy. Herein, we developed a green bismuth-based double-network hydrogel (Bi@P-Cu) as a PTT/CDT synergistic platform for accelerated drug-resistant bacteria-infected wound healing. Bismuth (Bi) nanoparticles fabricated using a microwave method were used as a highly efficient and biocompatible PTT agent while the integration of a small amount of CDT agent Cu2+ endowed the hydrogel with excellent mechanical and self-healing properties, markedly increased photothermal efficiency, promoted cell migration ability, and negligible toxicity. Importantly, PTT enhanced the production of hydroxyl radicals in CDT and the destruction of bacterial cell membranes, which in turn enhanced the thermal sensitivity of bacteria. This synergistic anti-bacterial effect, together with the demonstrated capability to promote angiogenesis and anti-inflammation as well as enhanced fibroblast proliferation, led to accelerated wound healing in a full-thickness mouse model of resistant bacterial infection. This study provides an effective and safe strategy to eliminate drug-resistant bacteria and accelerate wound healing through green, non-antibiotic, double-network hydrogel-mediated synergistic PTT and CDT.

Lonidamine liposomes to enhance photodynamic and photothermal therapy of hepatocellular carcinoma by inhibiting glycolysis

Phototherapy, including photodynamic therapy (PDT) and photothermal therapy (PTT), has great promise in the treatment of cancer. However, there are many obstacles that can restrict the therapeutic efficacy of phototherapy. The hypoxic tumor microenvironment can restrict the production of reactive oxygen species (ROS) in PDT. As for PTT, the thermotolerance of cancer cells may lead to ineffective PTT. In this study, IR780 and glycolysis inhibitor lonidamine (LND)-encapsulated liposomes are prepared for photodynamic and photothermal therapy of hepatocellular carcinoma. IR780 can be used as a photosensitizer and photothermal agent for simultaneous PDT and PTT after being irradiated with 808 nm laser. LND can reduce the oxygen consumption of cancer cells by inhibiting glycolysis, which will relieve tumor hypoxia and produce more ROS for PDT. On the other hand, energy supply can be blocked by LND-induced glycolysis inhibition, which will inhibit the production of heat shock proteins (HSPs), reduce the thermotolerance of tumor cells, and finally enhance the therapeutic efficacy of PTT. The enhanced PTT is studied by measuring intracellular HSPs, ATP level, and mitochondrial membrane potential. The antitumor effect of IR780 and LND co-loaded liposomes is extensively investigated by in vitro and in vivo experiments. This research provides an innovative strategy to simultaneously enhance the therapeutic efficacy of PDT and PTT by inhibiting glycolysis, which is promising for future creative approaches to cancer phototherapy.

Bromine Substitution Improves the Photothermal Performance of π-Conjugated Phototheranostic Molecules.

NIR-II fluorescence imaging-guided photothermal therapy (PTT) has been widely investigated due to its great application potential in tumor theranostics. PTT is an effective and non-invasive tumor treatment method that can adapt to tumor hypoxia; nevertheless, simple and effective strategies are still desired to develop new materials with excellent PTT properties to meet clinical requirements. In this work, we developed a bromine-substitution strategy to enhance the PTT of A-D-A'-D-A π-conjugated molecules. The experimental results reveal that bromine substitution can notably enhance the absorptivity (ϵ) and photothermal conversion efficiency (PCE) of the π-conjugated molecules, resulting in the brominated molecules generating two times more heat (ϵ808 nm ×PCE) than their unsubstituted counterpart. We disclose that the enhanced photothermal properties of bromine-substituted π-conjugated molecules are a combined outcome of the heavy-atom effect, enhanced ICT effect, and more intense bromine-mediate intermolecular π-π stacking. Finally, the NIR-II tumor imaging capability and efficient PTT tumor ablation of the brominated π-conjugated materials demonstrate that bromine substitution is a promising strategy for developing future high-performance NIR-II imaging-guided PTT agents.

Gold-Crowned Bismuth-Based Nanocomposites for Sonodynamic, Photothermal, and Chemotherapeutic Cancer Therapy.

Conventional inorganic semiconductor nanoparticles have emerged as photothermal agents in photothermal therapy and as sonosensitizers in sonodynamic therapy. However, their weak drug-loading capabilities and the deficient techniques for multifunctional inorganic nanoparticles limit their applications. A bismuth-based gold-crowned nanocomposite (BACN) was rationally designed and successfully synthesized and could then be used to prepare nanoplatforms with excellent biocompatibilities for synergistic therapy and real-time imaging. Because of the constituent gold nanoparticles and pyridine, the nanoplatforms functioned as drug delivery vehicles, ultrasonically activated sonosensitizers, and photothermal agents. The BACNs exhibited excellent photothermal conversion efficiency (79.1%) in the second near-infrared biowindow (1064 nm). Cellular and mouse experiments demonstrated that under laser and ultrasound irradiation bufalin-loaded BACNs significantly reduced cancer cell counts and completely eradicated tumors, along with great therapeutic biosafety and no discernible recurrence. Additionally, BACNs were also used as contrast agents in computed tomography-photoacoustic imaging. The versatile BACN nanoplatform with multitreatment effects and trimodal imaging properties shows immense potential as an antitumor nanotherapeutic system.

Hybrid FeWO4-Hyaluronic Acid Nanoparticles as a Targeted Nanotheranostic Agent for Multimodal Imaging-Guided Tumor Photothermal Therapy.

Development of versatile nanoplatform still remains a great challenge due to multistep synthesis and complicated compositions. Therefore, it is significant to develop a facile method to synthesize a nanocomposite to achieve multimodal imaging and even imaging-guided cancer therapeutics. In our study, hyaluronic acid-functionalized iron (II) tungstate nanoparticles (HA-FeWO4 NPs) were successfully synthesized as a versatile nanoplatform by a facile one-pot hydrothermal procedure. The formed multifunctional HA-FeWO4 NPs were investigated via a series of characterization techniques, which demonstrated good biocompatibility, excellent dispersion, low cytotoxicity, active tumor-targeting ability and high photothermal efficiency. Furthermore, tumor was clearly visualized by HA-FeWO4 NPs with multimodal imaging of infrared thermal imaging, magnetic resonance imaging, computed tomography imaging in 4T1 tumor bearing mice. More importantly, HA-FeWO4 could achieve multimodal imaging-guided photothermal therapy of 4T1 tumors. The constructed HA-FeWO4 NPs have great potential as ideal nanotheranostic agents for multimodal imaging and even imaging-guided cancer theranostics in biological systems.

Chaotropic Effect-Induced Self-Assembly of the Malachite Green and Boron Cluster for Toxicity Regulation and Photothermal Therapy.

Malachite green (MG), a toxic antibacterial agent, is widely used in the farming industry. Effectively regulating the biotoxicity of this highly water-soluble cationic dye is challenging. Here, we present a novel strategy to reduce the biotoxicity of MG through the self-assembly of MG and the closo-dodecaborate cluster ([B12H12]2-) driven by the chaotropic effect. [B12H12]2- and MG in an aqueous solution can rapidly form an insoluble cubic-type supramolecular complex (B12-MG), and the original toxicity of MG is completely suppressed. Surprisingly, this supramolecular complex, B12-MG, has a strong UV-vis absorption peak at 600-800 nm and significant photothermal conversion efficiency under 660 nm laser irradiation. On this basis, B12-MG, the supramolecular complex, can be used as an efficient photothermal agent for antimicrobial photothermal therapy (PTT) both in vitro and in vivo. As a molecular chaperone of MG, [B12H12]2- not only can be applied as an antidote to regulate the biotoxicity of MG but also provides a novel method for the construction of photothermal agents for PTT based on the chaotropic effect.

Synergistic coating strategy combining photodynamic and photothermal properties along with reinforcing corrosion protection fabricated on magnesium alloys

Postoperative infections of bone implants and loss of mechanical strength due to the corrosion are two major obstacles in the pathway for the magnesium alloys applications in biomedical region. To resolve above issues, a novel hybrid coating, MAO/EPR/Gel, is prepared on AZ31B magnesium alloys, in which the photodynamic therapy (PDT) and photothermal therapy (PTT) agents are combined together to form Er@PDA-RB and they are inserted in the micropores of micro-arc oxidation (MAO) coating rather than doping in it. The gelatin is utilized to prevent the leaking of Er@PDA-RB and it would be decomposed spontaneously in the human body. The |Z|0.01Hz of MAO/EPR and MAO/EPR/Gel are 4.35 × 104 Ω cm2 and 6.99 × 104 Ω cm2, which is much larger than that of MAO coating and bare AZ31B Mg alloy with the values of 3.70 × 104 Ω cm2 and 1.50 × 103 Ω cm2, respectively. The antibacterial ratio for E. coli reaches 93.9% under 980nm near-infrared (NIR) irradiation within 60min. Moreover, the MAO/EPR/Gel coating displays the excellent cytocompatibility with the HL-7702 cell viability > 75% with or without 980nm NIR irradiation. This multifunctional integrated coating accomplishes both PDT and PTT functions with only one NIR irradiation without sacrificing the anti-corrosion feature, which exhibits a promising application for magnesium alloys in biomedical applications.

Gold mineralized “hybrid nanozyme bomb” for NIR-II triggered tumor effective permeation and cocktail therapy

Lung cancer is one of the most common malignant tumors with the fastest increase in the incidence rate and mortality. Even after maximum tumor resection assistance with a radiotherapy and chemotherapy combination, the recurrence of non-small cell lung cancer is still inevitable. In addition, low targeting efficiency and poor permeability of drug delivery systems strongly affect the therapeutic efficiency of anti-cancer drugs on non-small cell lung cancer. Here we designed a gemcitabine (GEM) loaded arginine-glycine-aspartic acid-cysteine (RGDc)-modified gold mineralization “hybrid nanozyme bomb” (RGTG) to overcome those obstacles. RGDc modification improved the active targeting of liposomes to the tumor tissues with the second near-infrared (NIR-II)-triggered gold-shell disruption and GEM release. The collapsed gold-shell particles with a smaller size could penetrate the tumor solid barrier and act as photothermal therapy (PTT) agents to improve PTT therapy and starvation therapy via generating gluconic acid and reactive oxygen species (ROS). Moreover, the resting reversal effect of gold particles on tumor fibroblasts can achieve accelerating tumor penetration of gold particles and GEM. Compared to monotherapy, RGTG showed significant improvement in tumor inhibition, with a tumor volume reduction of 83% compared to the control group, which provides a promising tumor treatment platform for non-small cell lung cancer (NSCLC).

Furan‐modified thiadiazolo quinoxaline as an electron acceptor for constructing second near‐infrared aggregation‐induced emission fluorophores for beyond 1300 nm fluorescence/photoacoustic imaging and photothermal therapy

AbstractCreation of new fluorophores is important for understanding the structure–property relationship, by which the required optical properties are likely to be attained. Herein, through theory calculation, it is found that furan‐modified thiadiazolo quinoxaline acting as an electron acceptor can endow donor–acceptor–donor (D–A–D) type second near‐infrared (NIR‐II) fluorophores with longer emission wavelength than the other thiadiazolo quinoxaline‐based acceptors containing pyridine, pyrrole, thiophene, and phenyl groups, respectively. On the basis of this theoretical prediction, a D–A–D type NIR‐II fluorophore with 6,7‐di(furan‐2‐yl)‐[1,2,5]thiadiazolo[3,4‐g] quinoxaline (DFTQ) as the acceptor and dithieno[3,2‐b:2′,3′‐d]pyrrole (DTP) as the donor is designed and synthesized, and the aggregation‐induced emission (AIE) function is further achieved by introducing the AIE units of tetraphenylethylene (TPE) and triphenylamine (TPA), respectively, totally forming three NIR‐II fluorophores DFTQ–DTP, DFTQ–DTPE, and DFTQ–DTPA. For biological applications, the fluorophores are encapsulated by amphiphilic DSPE–PEG2000 to generate water‐dispersible nanoparticles (NPs). Almost the whole emission of each of the NPs falls into the NIR‐II spectral range, with part emission beyond 1300 nm. By using DFTQ–DTPA NPs as the contrast and photothermal therapy (PTT) agent, high‐resolution in vivo fluorescence imaging is achieved in the greater than 1300 nm window, and their good performance in photoacoustic imaging and high tumor PTT efficacy in tumor‐bearing mice are also demonstrated. Taken together, this work mainly provides a strong electron acceptor for constructing long‐emitting fluorophores, and by using the electron acceptor, a AIE fluorophore with desirable quantum yield (QY) and photothermal conversion efficienciy (PCE) is synthesized and demonstrated to be promising in fluorescence/photoacoustic imaging and PTT.

Polybenzoxazines as new photothermal therapy agents

To make photothermal therapy an attractive alternative to conventional cancer treatments, the development of novel photothermal agents with enhanced properties is demanded. To tackle this challenge, herein we explored the use of polybenzoxazines, a well-known class of phenolic resins. Two different types of polybenzoxazine materials were prepared as potential photothermal agents: water-soluble polybenzoxazines as well as nanoparticles of hydrophobic polybenzoxazines, which can be generated in situ by polymer addition to cell culture medium. For both systems, irradiation with visible light led to significant photothermal effects, whose application to photoinduce human breast cancer cell’s death was investigated in vitro. The best results were obtained for polybenzoxazine nanostructures, which exhibited successful cell internalization, minimal cytotoxicity in the dark and efficient photothermal killing of cancer cells upon illumination with high-penetrating red light. In combination with their low cost and facile preparation, this makes these polymer nanomaterials highly promising for photothermal therapy applications.

Influence of PEGylation on WS2 Nanosheets and Its Application in Photothermal Therapy.

Photothermal therapy (PTT) is an alternative cancer therapy with minimal side effects and higher efficiency and selectivity. In this study, WS2 nanosheets were developed by ultrasonic exfoliation with different ratios of polyethylene glycol (PEG), and their effects on physicochemical properties were studied. The utilization of PEG during sonication significantly influenced the size and thickness of the resulting WS2 nanosheet layers, which was confirmed through scanning electron microscopy, atomic force microscopy, and dynamic light scattering analyses. PEG functionalization also improved the dispersibility of WS2 in aqueous solution by making its surface hydrophilic, which resulted in better biocompatibility. The intrinsic near-infrared absorbance of the nanosheets positions them as valuable agents for PTT. The study further explores the efficacy of these nanosheets as photothermal agents in the ablation of MDAMB-231 breast cancer cells. Although the use of PEG to demonstrate exfoliation and biocompatibility for WS2 has been reported previously, the effect of PEGylation on various physicochemical properties has not been studied in-depth until now. This study paves the way for the use of highly versatile PEG across a range of 2D material systems.