Photothermal Ablation Therapy Research Articles

Polylysine-modified near-infrared-emitting carbon dots assemblies: Amplification of tumor accumulation for enhanced tumor photothermal therapy

A key challenge to enhance the therapeutic outcome of photothermal therapy (PTT) is to improve the efficiency of passive targeted accumulation of photothermal agents at tumor sites. Carbon dots (CDs) are an ideal choice for application as photothermal agents because of their advantages such as adjustable fluorescence, high photothermal conversion efficiency, and excellent biocompatibility. Here, we synthesized polylysine-modified near-infrared (NIR)-emitting CDs assemblies (plys-CDs) through post-solvothermal reaction of NIR-emitting CDs with polylysine. The encapsulated structure of plys-CDs was confirmed by determining morphological, chemical, and luminescent properties. The particle size of CDs increased to approximately 40 ± 8 nm after polylysine modification and was within the size range appropriate for achieving superior enhanced permeability and retention effect. Plys-CDs maintained a high photothermal conversion efficiency of 54.9 %, coupled with increased tumor site accumulation, leading to a high efficacy in tumor PTT. Thus, plys-CDs have a great potential for application in photothermal ablation therapy of tumors.

Assembly-enhanced indocyanine green nanoparticles for fluorescence imaging-guided photothermal therapy.

The development of theranostic agents that offer complete biocompatibility, coupled with enhanced diagnostic and therapeutic performance, is crucial for fluorescence imaging-guided photothermal therapy in anti-tumor applications. However, the fabrication of nanotheranostics meeting the aforementioned requirements is challenged by concerns regarding biosafety and limited control over construction. Herein, we reported a class of fluorescence imaging-guided photothermal theranostic nanomaterials that are composed of amino acid derivatives and clinically used small photoactive indocyanine green molecules. Through manipulation of noncovalent interactions, these binary building blocks can co-assemble into nanoparticles in a tunable manner. Significantly, such construction not only maintained the fluorescence properties of photoactive molecules, but also enhanced their stability to overcome barriers from photodegradation and complex physiological conditions. These collective features integrated their precise anti-tumor applications, including fluorescence imaging diagnosis and photothermal ablation therapy. This study reported a class of nanotheranostics characterized by biocompatibility, adjustable construction, and robust stability, which are beneficial for the clinical translation of fluorescence imaging-guided photothermal therapy against tumors.

Magnetic Mesoporous Janus Microrollers for Combined Chemo‐ and Photothermal Ablation Therapy

AbstractMobile microrobots have been proposed as a promising approach to overcome the limitations of traditional drug/gene delivery systems. Magnetically actuated surface rolling microrobots, or magnetic surface microrollers, have shown potential for navigation in physiologically relevant environments due to their robust locomotion characteristics. Although much is known about their locomotion abilities in various environments, the full extent of their potential in medical applications has yet to be fully explored. Here, the potential of surface microrollers for combined chemo‐ and photothermal ablation therapy under medical imaging modalities is demonstrated. The surface microrollers are half‐coated with magnetic material, allowing for photothermal heating and magnetic locomotion, and loaded with a biopharmaceutics classification system (BCS) class IV anti‐cancer drug, Docetaxel (DTX), for combined therapy. Synergistic action of on‐demand photothermal ablation and the controlled release of DTX result in the efficient elimination of cancer cells. Furthermore, microrollers can be detected ex vivo with magnetic resonance imaging (MRI) and photoacoustic imaging (PA), highlighting the potential of surface microrollers for future targeted medical applications.

The role of surface modification in improving the effectiveness of CuS nanorods for cancer ablation therapy and antibacterial applications

We report a new methodology to synthesize CuS nanorods (CuS NRs) via hydrothermal route, and surface modified with chitosan (CS) and folic acid (FA) to demonstrate the role of surface modification in photo-thermal heat generation and cancer photo ablation therapy. The electron microscopy investigations showed the formation of rod-shaped CuS nanomaterial and the length and diameter of nanorods (NRs) were found to be ∼55 and 22 nm, respectively. The surface modification of CuS NRs was investigated by UV–Vis spectroscopy, FTIR spectroscopy, dynamic light scattering technique, and Raman spectroscopy. Without any compromise in photo-thermal heat generation, the surface modification significantly improved biocompatibility, cancer cell cytotoxicity, and anti-bacterial activity. The photothermal heat generation experiments with 808 nm laser light revealed that the temperature increase was found to be 54 ℃ for surface modified FA-CS@CuS NRs at 500 µg/mL which increased to ∼100 ℃ when the laser power intensity was increased from 0.5 to 1.5 W/cm2. The photothermal conversion efficiency (PCE) was estimated to be 38.6% for FA-CS@CuS NRs. Notably, the photothermal heat generation is significantly influenced by CuS NRs concentration and laser power intensity. The anticancer activity investigations against HCT116 cancer cells revealed enhanced cytotoxicity for cancer cells owing to synergistic effects of hyperthermia and generation of highly toxic hydroxyl radicals (·OH) induced by the release of Cu2+ions. The surface-modified FA-CS@CuS NRs showed excellent antibacterial activity against Escherichia coli and Staphylococcus aureus. Hence, the proposed FA-CS@CuS NRs can be a suitable nanoagent for effective targeted anticancer and photothermal ablation treatment.

Microfluidic Formulation of Curcumin-Loaded Multiresponsive Gelatin Nanoparticles for Anticancer Therapy.

Current anticancer research shows that a combination of multiple treatment methods can greatly improve the killing of tumor cells. Using the latest microfluidic swirl mixer technology, combined with chemotherapy and photothermal-ablation therapy, we developed multiresponsive targeted antitumor nanoparticles (NPs) made of folate-functionalized gelatin NPs under 200 nm in size and with encapsulated CuS NPs, Fe3O4 NPs, and curcumin (Cur). By exploring gelatin's structure, adjusting its concentration and pH, and fine-tuning the fluid dynamics in the microfluidic device, the best preparation conditions were obtained for gelatin NPs with an average particle size of 90 ± 7 nm. The comparative targeting of the drug delivery system (DDS) was demonstrated on lung adenocarcinoma A549 cells (low level of folate receptors) and breast adenocarcinoma MCF-7 cells (high level of folate receptors). Folic acid helps achieve targeting and accurate delivery of NPs to the MCF-7 tumor cells. The synergistic photothermal ablation and curcumin's anticancer activity are achieved through infrared light irradiation (980 nm), while Fe3O4 is guided with an external magnetic field to target gelatin NPs and accelerate the uptake of drugs, thus efficiently killing tumor cells. The method described in this work is simple, easy to repeat, and has great potential to be scaled up for industrial production and subsequent clinical use.

State-of-the-art therapeutic strategies for targeting cancer stem cells in prostate cancer.

The development of new therapeutic strategies is on the increase for prostate cancer stem cells, owing to current standardized therapies for prostate cancer, including chemotherapy, androgen deprivation therapy (ADT), radiotherapy, and surgery, often failing because of tumor relapse ability. Ultimately, tumor relapse develops into advanced castration-resistant prostate cancer (CRPC), which becomes an irreversible and systemic disease. Hence, early identification of the intracellular components and molecular networks that promote prostate cancer is crucial for disease management and therapeutic intervention. One of the potential therapeutic methods for aggressive prostate cancer is to target prostate cancer stem cells (PCSCs), which appear to be a primary focal point of cancer metastasis and recurrence and are resistant to standardized therapies. PCSCs have also been documented to play a major role in regulating tumorigenesis, sphere formation, and the metastasis ability of prostate cancer with their stemness features. Therefore, the current review highlights the origin and identification of PCSCs and their role in anti-androgen resistance, as well as stemness-related signaling pathways. In addition, the review focuses on the current advanced therapeutic strategies for targeting PCSCs that are helping to prevent prostate cancer initiation and progression, such as microRNAs (miRNAs), nanotechnology, chemotherapy, immunotherapy, the clustered regularly interspaced short palindromic repeats (CRISPR)/CRISPR-associated protein 9 (Cas9) gene-editing system, and photothermal ablation (PTA) therapy.

Highly localized, efficient, and rapid photothermal therapy using gold nanobipyramids for liver cancer cells triggered by femtosecond laser

In this study, the photothermal effect and up-conversion florescence imaging effect of gold nanobipyramids in liver cancer cells are investigated theoretically and experimentally to explore the photothermal ablation tumor therapy with higher photothermal conversion efficiency, shorter laser action time, smaller action range and lower laser power. The small-size gold nanobipyramids with good biocompatibility and infrared absorption peak located in the first biological window are synthesized. Femtosecond laser is focused on the nanobipyramids clusters in cells and the cells die after being irradiated for 20 s at a power as low as 3 mW. In contrast, the control cells die after irradiation with 30 mW laser for 3 min. The theoretical simulation results show that: under femtosecond laser irradiation, the local thermal effect of gold nanoclusters is produced in the range of hundreds of square nanometers and the temperature rises by 516 °C in 106 picoseconds. This therapy reduces the treatment time to seconds level, and the treatment range to square micrometer level, the power to milliwatt level. In this treatment, cells die by apoptosis rather than necrosis, which reduces inflammation. This result opens up a new way to develop photothermal ablation therapy with less side effects and more minimally invasive.

Nanoheterostructure by Liquid Metal Sandwich-Based Interfacial Galvanic Replacement for Cancer Targeted Theranostics.

Nanoheterostructures with exquisite interface and heterostructure design find numerous applications in catalysis, plasmonics, electronics, and biomedicine. In the current study, series core-shell metal or metal oxide-based heterogeneous nanocomposite have been successfully fabricated by employing sandwiched liquid metal (LM) layer (i.e., LM oxide/LM/LM oxide) as interfacial galvanic replacement reaction environment. A self-limiting thin oxide layer, which would naturally occur at the metal-air interface under ambient conditions, could be readily delaminated onto the surface of core metal (Fe, Bi, carbonyl iron, Zn, Mo) or metal oxide (Fe3 O4 , Fe2 O3 , MoO3 , ZrO2 , TiO2 ) nano- or micro-particles by van der Waals (vdW) exfoliation. Further on, the sandwiched LM layer could be formed immediately and acted as the reaction site of galvanic replacement where metals (Au, Ag, and Cu) or metal oxide (MnO2 ) with higher reduction potential could be deposited as shell structure. Such strategy provides facile and versatile approaches to design and fabricate nanoheterostructures. As a model, nanocomposite of Fe@Sandwiched-GaIn-Au (Fe@SW-GaIn-Au) is constructed and their application in targeted magnetic resonance imaging (MRI) guided photothermal tumor ablation and chemodynamic therapy (CDT), as well as the enhanced radiotherapy(RT) against tumors, have been systematically investigated.

Efficient improvement in chemo/photothermal synergistic therapy against lung cancer using Bi@Au nano-acanthospheres

Novel highly hydrophilic and biocompatible bismuth nanospheres with gold nanoparticles growing outside (Bi@Au nano-acanthospheres, Bi@Au NASs) were synthesized through a simple procedure, which demonstrated to be a promising photothermal agent owing to the ultrahigh photothermal conversion efficiency (η = 46.6 %). The as-prepared Bi@Au NASs showed excellent blood compatibility and fairly low cytotoxicity to human lung cancer A549 cells, as well as efficient photothermal ablation (PTA) therapy induced by a near-infrared laser. Under the 808 nm laser radiation, the tumour temperature could be elevated by ∼25 °C high enough to kill the cancer cells. Moreover, the anticancer drug doxorubicin hydrochloride (DOX) was successfully loaded in Bi@Au NASs with a loading content as high as 16.78 % and released under a pH sensitive release profile, a characteristic beneficial for intravenous delivery of DOX into cancer cells for chemotherapy. The presence of the Bi element enabled Bi@Au NASs to act as a favourable computed tomography (CT) contrast medium for CT imaging-guided tumour treatment. Compared with cancer treatment through either photothermal therapy or chemotherapy, the chemo-photothermal synergistic therapy using Bi@Au NASs as both a photothermal agent and a drug carrier has efficiently enhanced the in vitro and in vivo therapeutic effects in cancer treatment.

Integrated manganese (III)-doped nanosystem for optimizing photothermal ablation: Amplifying hyperthermia-induced STING pathway and enhancing antitumor immunity

Despite the great promise initially demonstrated by photothermal ablation (PTA) therapy, its inability to completely ablate large tumors is problematic, because this has been found to result in residual tumors at ablation margins and bring a relative high rate of subsequent recurrences and metastases. To address this issue, we herein report a smart photothermal nanosystem (PBM) based on FDA-approved Prussian blue (PB) nanoparticles, doped with Mn (III) to suppress the tumor debris left by incomplete ablation. Notably, our study demonstrated that PTA-induced hyperthermia plays a crucial role in initiating the cGAS-STING pathway by generating damaged cytosolic DNA. This PBM nanosystem, which consumes glutathione and continuously releases Mn(II), further amplifies the PTA-induced cGAS-STING pathway in CT26 colon and 4T1 breast tumor models. Moreover, treatment with PBM following PTA boosted the robust immune response in situ and extended to the whole body with a remarkable suppression effect on both local residual and distant tumors. This work, which improves the antitumor efficacy of nonablated areas utilizing hyperthermia-enhanced immune therapy, may therefore provide a promising adjuvant antitumor strategy for the issue of incomplete ablation. Statement of significanceThis work discovered, for the first time, that photothermal ablation-induced hyperthermia plays a crucial role in initiating the cGAS-STING pathway. Taking advantage of this finding, we developed a smart photothermal material (PBM) tailored for incomplete tumor ablation. This integrated Mn(III)-doped nanosystem (PBM) demonstrated superior therapeutic benefits due to the thermal ablation process and immune enhancement. As the photothermal ablation-induced cGAS-STING pathway was triggered, the released Mn(III) consumes GSH while continuously transferred to Mn(II), which further amplified STING activation and facilitated a more robust antitumor immunity, thereby remarkably inhibiting both local residual and distant tumors in virtue of the biological changes under thermal ablation.

Localized Photothermal Ablation Therapy of Obstructive Rectal Cancer Using a Nanofunctionalized Stent in a Mouse Model.

The self-expanding metal stent (SEMS) is a versatile, palliative treatment method for unresectable, malignant, non-vascular strictures. Colorectal cancer (CRC) is one of the candidates for the application of the SEMS, in combination with the photothermal ablation (PTA) technique that enhances its therapeutic efficacy. The objective of this study was to investigate the efficacy of stent-mediated PTA therapy in an endoscopy-guided, orthotopic rectal cancer model. A total of 30 of 40 mice with the tumor size of grade 4 were included and were divided into three groups of 10 mice each. Group A underwent a gold nanoparticle (AuNP)-coated SEMS but no near-infrared (NIR) irradiation, group B received an uncoated control SEMS with NIR irradiation, and group C received a AuNP-coated SEMS and NIR irradiation together. Colonoscopy and in vivo imaging, immunohistochemical analysis, and quantitative reverse-transcription polymerase chain reaction of major tumor markers were performed. Stent placement and PTA were technically successful using colonoscopy. The tumor grade reduction after PTA is significant in group C, compared with groups A or B (p < 0.001). Molecular analysis validated this observation with a significantly reduced Mapk1 proliferation marker or increased Jnk expression. Histological analysis confirmed the localized PTA therapy using AuNP-coated SEMS profoundly ablated tumor outgrowth through the stent. Our results indicate that this novel strategy of localized PTA therapy could be a promising option for palliative treatment of CRC and to support prolonged stent patency with a decreased tumor volume.

Clinical translation of silica nanoparticles.

Silica nanoparticles have entered clinical trials for a variety of biomedical applications, including oral drug delivery, diagnostics, plasmonic resonance and photothermal ablation therapy. Preliminary results indicate the safety, efficacy and viability of silica nanoparticles under these clinical scenarios.

Integrin αvβ3-targeted polydopamine-coated gold nanostars for photothermal ablation therapy of hepatocellular carcinoma.

Photothermal therapy (PTT) has emerged as a promising cancer therapeutic method. In this study, Arg-Gly-Asp (RGD) peptide-conjugated polydopamine-coated gold nanostars (Au@PDA-RGD NPs) were prepared for targeting PTT of hepatocellular carcinoma (HCC). A polydopamine (PDA) shell was coated on the surface of gold nanostars by the oxidative self-polymerization of dopamine (termed as Au@PDA NPs). Au@PDA NPs were further functionalized with polyethylene glycol and RGD peptide to improve biocompatibility as well as selectivity toward the HCC cells. Au@PDA-RGD NPs showed an intense absorption at 822 nm, which makes them suitable for near-infrared-excited PTT. Our results indicated that the Au@PDA-RGD NPs were effective for the PTT therapy of the αVβ3 integrin receptor-overexpressed HepG2 cells in vitro. Further antitumor mechanism studies showed that the Au@PDA-RGD NPs-based PTT induced human liver cancer cells death via the mitochondrial–lysosomal and autophagy pathways. In vivo experiments showed that Au@PDA-RGD NPs had excellent tumor treatment efficiency and negligible side effects. Thus, our study showed that Au@PDA-RGD NPs could offer an excellent nanoplatform for PTT of HCC.

Disulfiram-loaded copper sulfide nanoparticles for potential anti-glioma therapy

Disulfiram (DSF) is an effective copper (Cu2+)-dependent antitumor agent. In the present study, we explored use of transferrin (Tf)-modified DSF/copper sulfide (CuS) nanocomplex (Tf-DSF/CuS) for glioma therapy. Tf was used as glioma targeting motifs, DSF as an anticancer agent, and CuS as a source of Cu2+ ions and a photothermal agent. DSF was loaded on CuS by metal-chelation, and released from the nanocomplex under acidic condition. The Tf-DSF/CuS complex exhibited high cytotoxic effect in vitro. Notably, cytotoxic activity was correlated with pH triggered release of Cu2+ which initiated non-toxicity to toxicity switch of DSF. Ultrasound-targeted microbubble destruction (UTMD) technique was used for highly selective accumulation of intravenous injected Tf-DSF/CuS in the glioma orthotopic tumor as compared with the free drugs and non-targeted DSF/CuS groups. Magnetic resonance imaging and pathological examinations showed that Tf-DSF/CuS effectively suppressed tumor growth, with an inhibition ratio of ~85%. Additionally, DSF load did not compromise photothermal conversion ability of CuS nanoparticles. Efficacy of the photothermal ablation therapy of Tf-DSF/CuS was evaluated under 808 nm laser irradiation both in vitro and in vivo. These findings show that copper-sulfide based disulfiram nanoparticles are effective agents for anti-glioma therapy.

Brightly luminescent (NH4)xCs1-xPbBr3 quantum dots for in vitro imaging and efficient photothermal ablation therapy

Herein, we report for the first time a facile strategy for the highly efficient (NH4)xCs1-xPbBr3 quantum dots (QDs). By modulating the amount of ammonium, (NH4)xCs1-xPbBr3 QDs with different photoluminescence (PL) quantum yields (QY) were synthesized. The results of X-ray diffraction and X-ray photoelectron spectroscopy showed that the crystal structure of (NH4)xCs1-xPbBr3 was altered by incorporation of NH4+ cations into the CsPbBr3 lattice. The (NH4)xCs1-xPbBr3 QDs showed enhanced PL QY, higher photostability, and long-term storage stability compared to CsPbBr3 QDs. Furthermore, (NH4)xCs1-xPbBr3 QDs could be conjugated with a photothermal dye (IR780) via a one-pot reaction using poly(styrene-co-maleic anhydride) and IR780-MPTS. To the best of our knowledge, the present work is the first attempt integrating perovskite QDs and phototherapeutic molecules into one system (abbreviated as PQD-IR780), demonstrating good water dispersibility and high photothermal conversion efficiency of 57.85%. In vitro experiments performed to examine subcellular uptake showed high fluorescence brightness was observed in HeLa, B16F1, and HepG2 cancer cells cultured with PQD-IR780. The results indicate that the internalization mechanism for uptaking of PQD-IR780 inside HeLa cells is energy-dependent and caveolin-mediated endocytosis. The in vitro cell viability assays and photothermal therapy revealed that PQD-IR780 showed good biocompatibility and can induce hyperthermia upon laser irradiation.

A Photothermal Therapy Strategy for Monitoring Real-Time Temperature in Kidney Cancers by Injecting Gold Nanorods with Phosphors.

Photothermal ablation therapy (PTA) has been widely reported; however, it is not possible to predict the internal temperature of the tumor in real time that causes ineffective treatment and normal tissue burns. Here, we have designed a photothermal therapy strategy under real-time temperature monitoring by injecting gold nanorods (AuNRs) and NaYF₄: Yb3+ /Er3+ into the tumor site where AuNRs are used for PTA of cancer cells by converting the absorbed energy into heat and using Yb3+ , Er3+-NaYF ₄ phosphors to monitor the temperature inside the tumor. Our experiments confirm the effectiveness of this strategy, which is expected to be an aid in the development of real-time temperature monitoring and effective photothermal therapy for the treatment of cancers.

A PdMo bimetallene with precise wavelength adjustment and catalysis for synergistic photothermal ablation and hydrogen therapy of cancer at different depths

By delivering the idea of green and safe hydrogen energy and novel photothermal therapy to the biomedical field, engineering of therapeutic nanomaterials for treatment of major diseases (such as cancer) holds great significance. In this work, a novel PdMo bimetallene was synthesized by a solvothermal reduction method, and it was explored and applied in the field of anti-tumor therapy for the first time. The absorption peak of the PdMo bimetallene can be precisely adjusted in the NIR biological window (700-1350 nm) only by changing the synthesis time. At the same time, it also shows strong light absorption and high photothermal conversion efficiency. Specifically, the photothermal conversion efficiencies at 808 nm, 980 nm and 1064 nm are 43.1%, 51.7% and 69.15%, respectively. Surprisingly, a PdMo bimetallene is an efficient catalyst, which can effectively promote hydrogen production from the hydrolysis of ammonia borane (AB) under acidic and photothermal conditions. Benefitting from these excellent properties, a multifunctional composite nano therapeutic agent (PdMo@AB@HA) was developed via layer-by-layer surface modification with AB and hyaluronic acid (HA). In this way, the synergistic PTT/hydrogen therapy of PdMo@AB@HA composite nanosheets in the NIR-I and NIR-II windows (808 nm, 980 nm, and 1064 nm) on mouse tumor xenografts of different depths was realized. Furthermore, the controlled release of hydrogen, targeted endocytosis, efficient eradication of tumors of different depths and high biosafety were systematically proved in vitro and in vivo. This work not only provides a novel and efficient theranostic nanoplatform for efficient cancer theranostics, but also provides a new strategy for the development of safe and efficient new anti-tumor therapies.

Doxorubicin-loaded hollow gold nanospheres for dual photothermal ablation and chemoembolization therapy

BackgroundDoxorubicin-loaded hollow gold nanospheres (Dox@HAuNS) are a promising technology for simultaneous trans-arterial tumor-targeted chemotherapy delivery and thermal ablation. We evaluated the efficacy of intra-arterial delivery of Dox@HAuNS followed by photothermal ablation (PTA) in a rabbit model of liver cancer. Adult New Zealand white rabbits (N = 25) were inoculated with VX2 tumors into the left lobe of the liver. The animals were then randomized to sham surgery (N = 5), PTA only (N = 3), Dox@HAuNS only (N = 5), HAuNS + PTA (N = 5), and Dox@HAuNS + PTA (N = 7). Nanoparticles were delivered as an emulsion with Lipiodol (Guerbet, France) via a trans-arterial approach. Following nanoparticle delivery, PTA was performed using an 808-nm fibered laser at 1.5 W for 3 min. Thermography during PTA demonstrated a sustained elevation in tumoral temperature in both HAuNS + laser and Dox@HAuNS + laser treatment groups relative to animals that underwent laser treatment without prior nanoparticle delivery.ResultsThere was a significant decrease in tumor volumes in all three treatment arms relative to control arms (P = 0.004). Concentrations of intratumoral doxorubicin were significantly greater in animals treated with laser compared to those that were not treated with laser (P < 0.01).ConclusionsDoxorubicin-loaded HAuNS is a promising therapeutic agent for dual ablation/chemoembolization treatment of liver cancer.

Construction of CuS@Fe-MOF nanoplatforms for MRI-guided synergistic photothermal-chemo therapy of tumors

Integrated theranostic nanoplatforms with imaging and photothermal/drug-delivering functions have great advantages in cancer therapy, but the design and preparation of the simple efficient nanoplatforms are still of great urgency. Herein, we report the construction of novel core-shell CuS@Fe-based metal-organic-framework (Fe-MOF) nanoplatforms by the co-precipitation/assembling growth of Fe-MOF shell on the surface of CuS nanoplate. The resulting CuS@Fe-MOF nanoparticles (NPs) consist of hexagonal-shaped CuS nanoplate core with an average size of ~85 nm and amorphous Fe-MOF shells with an average thickness of 16 nm. CuS@Fe-MOF NPs are then surface-modified with lipids, and they exhibit the increased NIR photoabsorption and photothermal conversion efficiency (39.7%), resulting from localized surface plasmon resonance (LSPR) effect of CuS. The presence of Fe-MOF shell confers the efficient loading (27.5%) of doxorubicin (DOX), pH-responsive releasing ability, and strong magnetic resonance imaging (MRI) ability. Especially, the photothermal effect of CuS and the released DOX from CuS@Fe-MOF-DOX result in the most efficient death of cancer cells in vitro. When CuS@Fe-MOF-DOX dispersion was injected into the tumor, the tumor-bearing mice could be monitored by MR and thermal imaging. Furthermore, the tumors could be inhibited and destroyed due to the synergistic photothermal-chemo therapy, remarkably better than that from photothermal ablation therapy or chemotherapy alone. Simultaneously, no noticeable side-effects can be found for mice. Therefore, the present CuS@Fe-MOF-DOX can act as a biocompatible multifunctional nanoplatform for MRI-guided synergistic photothermal-chemo therapy of tumors.

Lung cancer photothermal ablation by low-power near-infrared laser and topical injection of indocyanine green.

Surgical treatment is the gold standard for the treatment of early-stage non-small-cell lung cancer. However, minimally invasive tumour ablation can be an alternative treatment for patients not eligible for surgery due to comorbidities. The aim of this study was to evaluate the efficacy of photothermal ablation therapy using low-power near-infrared laser and topical injection of indocyanine green (ICG), a photosensitizer, in a preclinical study using a rabbit VX2 lung cancer model. Six New Zealand white rabbits were used. Five hundred microlitres of a suspension containing 0.5 × 107 VX2 cancer cells with growth factor-reduced Matrigel was inoculated into the right lung using an ultrathin bronchoscope. Three rabbits were treated with laser ablation therapy with topical injection of ICG, whereas another 3 rabbits were treated with laser ablation alone. All tumours were irradiated with a laser with 500-mW output at 808 nm for 15 min. The tumours were examined histopathologically to assess the state of ablation. The maximum tumour surface temperatures in rabbits treated using ICG/laser and laser alone were higher than 58°C and lower than 40°C, respectively. The ablated areas in the rabbits treated with ICG/laser were significantly larger than those in the rabbits treated with laser alone (0.49 ± 0.27 vs 0.02 ± 0.002 cm2, respectively) (P < 0.05). The photothermal treatment using the combination of low-power near-infrared laser and topical injection of ICG can ablate a larger tumour area than laser treatment alone.