Effective Photothermal Agent Research Articles

A targeting multiple-stimuli responsive POSS-based smart nanomaterial for enhanced chemo-photothermal synergistic therapy

The combination of chemotherapy and photothermal therapy has garnered significant attention in the field of multimodal cancer therapy. However, achieving precise and controllable delivery of therapeutic agents remains a challenge. In this study, we designed a biocompatible smart nanomaterial (PSD-FA) for efficient loading of doxorubicin (DOX) through dynamic chemical bonding, with the aim of achieving responsive behavior to both the tumor microenvironment (TME) and external laser irradiation. The incorporation of PEG into the nanoplatform enhanced hydrophilicity of PSD-FA NPs. Folic acid (FA) served as a targeting ligand to guide the nanoparticles tumor sites. On one hand, SQ-N acted as an effective photothermal agent that efficiently converted light energy into heat energy upon stimulation by exogenous near-infrared light. This localized increase in temperature at the tumor site facilitated targeted killing of tumor cells. On the other hand, after photothermal therapy-induced tumor ablation, DOX was released in response to redox stimuli due to significantly higher concentrations of glutathione (GSH), an antioxidant presents in TME. This allowed deep penetration into the tumor tissue, expanding the attack area and inhibiting nucleic acid synthesis in tumor cells, ultimately leading to cell death. Both in vitro and in vivo experiments demonstrated excellent anticancer efficacy of PSD-FA NPs. Overall, this intelligent nanomaterial successfully achieved targeted drug delivery with redox-responsive release capabilities while synergistically combining chemo-photothermal therapies, thus exhibiting great potential for clinical applications.

Making the Brightest Ones Dim: Maximizing the Photothermal Conversion Efficiency of BODIPY-Based Photothermal Agents.

The successful implementation of photothermal therapy (PTT) in cancer treatment hinges on the development of highly effective photothermal agents (PTAs). Boron dipyrromethene (BODIPY) dyes, being well known for their high brightness and quantum efficiencies, are the antithesis of PTAs. Nonetheless, a systematic exploration of the photophysics and photothermal characteristics of a series of π-extended BODIPY dyes with high absorptivity in the near-infrared (NIR) region has achieved superior photothermal conversion efficiencies (>90%), in both monomeric state and nanoparticles after encapsulation in a biocompatible polyethyleneglycol 1,2-distearoyl-sn-glycero-3-phosphoethanolamine-N-[methoxy-(polyethylene glycol)-2000]. Optimal PTA candidates combine strong NIR absorption provided by extended donor-acceptor conjugation and an optimization of the electronic and steric effects of meso-substituents to maximize photothermal conversion performance. The PTT-optimized meso-CF3-BODIPY, TCF3PEn exhibits exceptional efficacy in inducing cancer cell apoptosis and in vivo tumor ablation using low-power NIR laser irradiation (0.3 Wcm-2, 808 nm) as well as excellent biological safety, underscoring its potential for advancing light-induced cancer therapies.

Photo-thermal catalysis for sustainable energy production and environmental treatment

Photo-thermal-catalysts (PTC) exceptional features and ability to concurrently solve sustainable energy requirements and environmental problems have drawn scientific interest. The photo-thermal effect is the process by which photo-thermal conversion materials transform radiant energy from light into thermal energy. The photo-thermal therapy of energy and environmental treatment faces the urgent task of developing effective photo-thermal agents to address complicated problem demands. In this study, we take a look at the fundamental principles and underlying process of photo-thermal material catalysis. In addition, this review provides a concise summary of the most up-to-date findings concerning photo-thermal catalysis materials, which have been aggressively researched for a wide-spread sustainable energy and environment treatment uses. In order to motivate the creation of a high-efficiency photo-thermal catalytic pathway, the criteria and techniques for designing photo-thermal catalysts are presented. This will make it possible for a better absorption of the whole spectrum of solar energy as well as a greater conversion of solar energy to heat. Theoretical direction is offered for the continued development of this technology, and the promise of the practical use of photo-thermal catalysis for different solar-driven interfacial photo-thermal conversion technologies is anticipated. This paper offers a unique perspective on photo-thermal catalysis focussing on the synergistic effects and suggesting a potential route for future applications.

Mucilage-assisted fabrication of molybdenum trioxide nanostructures for photothermal ablation of breast cancer cells.

Nanostructures have been used for various biomedical applications due to their optical, antibacterial, magnetic, antioxidant, and biocompatible properties. Cancer is a prevalent disease that severely threatens human life and health. Thus, innovative and effective therapeutic approaches are urgently required for cancer. Photothermal therapy (PTT) is a promising approach to killing cancer cells. In this investigation, we developed a low-cost, simple, green technique to fabricate molybdenum trioxide nanostructures (MNs) using Opuntia ficus-indica mucilage as a template. Moreover, the MNs were functionalized with folic acid (FA) for cancer PTT. The X-ray diffractometer results revealed that the prepared MNs have an orthorhombic crystal phase. The transmission electron microscope image of MNs shows a flake shape with 20-150nm diameter. The cytotoxicity of MNs and FA-conjugated MNs was studied in vitro. These cell viability assay results suggested that fabricated MoO3 nanostructures reduced 25% of cell viability in MCF-7 cells, even at high doses. However, even with high-dose treatment, FA/MNs do not cause significant cell death. Acridine orange/ethidium bromide (AO/EB) staining revealed DNA and chromatin condensation in MCF-7 cells exposed to MNs. Overall, the in vitro study results suggested that FA/MNs have excellent biocompatibility, which applies to biomedical applications. MNs dispersion temperature gradually increases from 26 to 58°C under 808nm laser irradiation. We found significant mortality rates after NIR irradiation in MNs- or FA/MNs-treated MCF-7 cells. These findings suggest that FA/MNs can be used as an effective photothermal agent to treat breast cancer.

Cuttlefish-Inspired Photo-Responsive Antibacterial Microparticles with Natural Melanin Nanoparticles Spray.

Topical antibiotics can be utilized to treat periodontitis, while their delivery stratagems with controlled release and long-lasting bactericidal inhibition are yet challenging. Herein, inspired by the defensive behavior of cuttlefish expelling ink, this work develops innovative thermal-responsive melanin-integrated porous microparticles (MPs) through microfluidic synthesis for periodontitis treatment. These MPs are composed of melanin nanoparticles (NPs), poly(N-isopropylacrylamide) (PNIPAM), and agarose. Benefiting from the excellent biocompatibility and large surface area ratio of MPs, they can deliver abundant melanin NPs. Under near-infrared irradiation, the melanin NPs can convert photo energy into thermal energy. This leads to agarose melting and subsequent shrinkage of the microspheres induced by pNIPAM, thereby facilitating the release of melanin NPs. In addition, the released melanin NPs can serve as a highly effective photothermal agent, displaying potent antibacterial activity against porphyromonas gingivalis and possessing natural anti-inflammatory properties. These unique characteristics are further demonstrated through in vivo experiments, showing the antibacterial effects in the treatment of infected wounds and periodontitis. Therefore, the catfish-inspired photo-responsive antibacterial MPs with controlled-release drug delivery hold tremendous potential in clinical antibacterial applications.

Quinoxalineimide-Based Semiconducting Polymer Nanoparticles as an Effective Phototheranostic for the Second Near-Infrared Fluorescence Imaging and Photothermal Therapy.

Multifunctional theranostics play a critical role in improving the efficacy of photothermal therapy and tumor fluorescence imaging; however, they require the integration of complex components into a single theranostic system, and their response in the second near-infrared (NIR-II) region is constrained by wavelengths of a photosensitizer. To address this issue, we herein developed a novel multifunctional thiazole-fused quinoxalineimide semiconducting polymer (named PQIA-BDTT), which exhibits NIR-II fluorescence and photothermal properties. PQIA-BDTT nanoparticles achieved an impressively high photothermal conversion efficiency (72.6%) in laser (1064 nm)-induced photothermal therapy at a safe maximum permissible exposure, demonstrating their capability as an effective photothermal agent. Moreover, PQIA-BDTT nanoparticles can be used as a reference for NIR-II fluorescence imaging under a low laser fluence. The tumor size and location in 4T1 mice intravenously injected with the PQIA-BDTT nanoparticles could be precisely identified through NIR-II fluorescence imaging, which also exhibited remarkable photothermal antitumor efficacy by in vitro and in vivo therapy. Overall, this study demonstrates that introducing a thiazole-fused quinoxalineimide acceptor unit into a donor-acceptor conjugated polymer is an effective strategy for the synthesis of novel multifunctional theranostic systems, which provides a novel platform for designing theranostic agents for biomedical applications.

Insight into the photothermal therapeutic impacts of silica-coated iron oxide nanocomposites

Recently, near-infrared photothermal therapy combined with targeted nano-sensitizer has been used for cancer eradication as it protects the surrounding tissues. Although iron oxide nanoparticles (INPs) are efficient photo-heat conversion agents, they tend to agglomerate, restricting their utility in medical applications. We prepared silica-coated INPs (SCINPs) to overcome this obstacle. The physical properties of INPs and SCINPs were evaluated using transmission electron microscope (TEM), dynamic light scattering (DLS), vibrating sample magnetometer (VSM), atomic force microscope (AFM) and X-RAY diffraction (XRD). The polydispersity index (PDI) value was 0.21 and 0.44 for INPs and SCINPs, respectively. Zeta potential measurements showed that the prepared nanoparticles had negative net surface charges with average values of −28 ± 4.21 and −48 ± 5 mv for INPs and SCINPs, respectively. This is a pioneered study that evaluate the photothermal therapeutic effect of silica coated iron oxide nanoparticles. In addition to evaluate their photothermal therapeutic effect, as nano photothermal agents, using comet assay and oxidative stress parameters. Also, their photothermal therapeutic effect were assessed using the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl-2H-tetrazolium bromide (MTT) assay. Photothermal assessment indicated that SCINPs could improve the photothermal therapy (PTT) because of their reproducible hyper-thermic and hypo-thermic effects with repeated treatment. Compared to INPs, SCINPs significantly improved the photothermal therapeutic behavior in treated cells by around 1.88 folds. SCINPs were more effective photothermal therapeutic agents and had considerable potential as novel therapeutic agents.

In vivo photothermal therapy monitored by multi-position calibrated photoacoustic thermometer

With the ability of monitoring both temperature and photothermal agents, the photoacoustic (PA) imaging is a promising guiding tool for the photothermal therapy (PTT). The calibration line which depicts the relative variation of PA amplitude with the temperature should be obtained before using PA thermometer. In existing study, a calibration line was generated based on the data from one spatial position, and used in the whole region of interesting (ROI). However, the generalization of this calibration line in ROI was not verified, especially for ROI with heterogeneous tissues. Moreover, the relationship between the distributions of photothermal agents and effective treatment area is not clear, hindering using photothermal agents’ distribution to optimize the administration-therapy interval. In this study, the distribution of effective photothermal agents and temperature in subcutaneously transplanted tumor mouse models were continuously monitored by 3D photoacoustic/ ultrasonic dual-modality imaging in 8 h after administration. With multiple micro-temperature probes in tumor and surrounding normal tissue, the PA thermometer was calibrated and evaluated at multiple spatial positions for the first time. The generalization in homologous tissue and tissue specificity in heterogeneous tissues of the PA thermometer calibration line were verified. Our study not only validated the effectivity of PA thermometer by proving the generalization of calibration line, but also removes a major obstacle that prevents applying the PA thermometer to a heterogeneous tissues ROI. The positive correlation between the proportion of effective treatment area and the proportion of effective photothermal agent area in the tumor was observed. Since the latter can be monitored with fast PA imaging, PA imaging can be employed as a convenient tool for seeking optimal administration-treatment interval.

Metal-Organic Frameworks Applications in Synergistic Cancer Photo-Immunotherapy

Conventional cancer therapies, such as radiotherapy and chemotherapy, can have long-term side effects. Phototherapy has significant potential as a non-invasive alternative treatment with excellent selectivity. Nevertheless, its applicability is restricted by the availability of effective photosensitizers and photothermal agents, and its low efficacy when it comes to avoiding metastasis and tumor recurrence. Immunotherapy can promote systemic antitumoral immune responses, acting against metastasis and recurrence; however, it lacks the selectivity displayed by phototherapy, sometimes leading to adverse immune events. The use of metal-organic frameworks (MOFs) in the biomedical field has grown significantly in recent years. Due to their distinct properties, including their porous structure, large surface area, and inherent photo-responsive properties, MOFs can be particularly useful in the fields of cancer phototherapy and immunotherapy. MOF nanoplatforms have successfully demonstrated their ability to address several drawbacks associated with cancer phototherapy and immunotherapy, enabling an effective and low-side-effect combinatorial synergistical treatment for cancer. In the coming years, new advancements in MOFs, particularly regarding the development of highly stable multi-function MOF nanocomposites, may revolutionize the field of oncology.

Regulating steric hindrances of perylenediimide to construct NIR photothermal J-aggregates with a large red-shift.

Perylene diimide (PDI)-based photothermal agents (PTAs) possess excellent stability and high photothermal conversion efficiency. However, developing PDIs with strong near-infrared absorption under biological conditions remains a challenge. In this study, we introduce a novel approach to facilitate the formation of J-aggregate-based PTAs with significantly red-shifted absorption by modulating steric hindrances of PDIs. PDIA, featuring larger steric hindrances at the bay position and smaller steric hindrances at the imide position, self-assembles into J-aggregates which exhibit a remarkable red-shift of over 100 nm. After encapsulation by DPSE-PEG, PDIA nanoparticles (PDIA-NPs) demonstrated a uniform and stable size, while retaining their significant red-shift. In vitro experiments demonstrated the great potential of PDIA-NPs in photothermal therapies for tumors and thrombi under 808 nm laser irradiation. This research provides valuable insights into the design of stable J-aggregates based on PDIs suitable for biological applications, paving the way for the development of more effective PTAs.

Near-infrared and highly photostable squaraine-based nanoparticles for photoacoustic imaging guided photothermal therapy

Effective photothermal agents (PTAs) are of particular importance for anticancer phototherapy. Nevertheless, conventional PTAs are frequently plagued by inadequate photostability, short-wavelength absorption, and low photothermal conversion efficiency (PCE). Herein, we designed and synthesized a near-infrared squaraine dye (SQ) with the maximum absorption wavelength at ∼710 nm. The squaraine dye demonstrates much enhanced photostability compared with indocyanine green (ICG), a commercial PTA. To improve the tumor targeting capacity, SQ was encapsulated into polymeric nanoparticles (SQ-NPs), which show a high photothermal conversion of 52.8% with strong photoacoustic signals upon 760 nm NIR laser irradiation. Through intravenous injection into tumor-bearing mice, SQ-NPs accumulate at the tumor site and efficiently inhibit the growth of tumor under photoacoustic image-guided photothermal therapy.

Fine‐Tuning Cu (II)‐Induced Self‐Assembly of Hydrophilic Cyanine Dyes for Enhanced Tumor Photothermal Therapy

AbstractSupramolecular self‐assembly of near‐infrared (NIR) dyes are believed to be a promising strategy to design effective photothermal agents for tumor photothermal therapy (PTT). However, due to the uncontrollable intermolecular interactions, accurately fine‐tuning the aggregated morphology of NIR dyes through adjusting their supramolecular self‐assembly is challenging. Here, based on organic–metal coordination interaction, a facile self‐assembly fine‐tuning strategy is proposed to adjust the aggregated morphology of heptamethine cyanine (Cy7) dyes, the well‐known NIR dyes. Three hydrophilic Cy7 derivatives Cy‐nCOOH (n = 1, 2, and 3) are synthesized, and then are coordinated with Cu2+to obtain different aggregates. Cy‐1COOH/Cu aggregates form partial J‐aggregates. Cy‐2COOH/Cu aggregates are amorphous. Noteworthily, Cy‐3COOH/Cu aggregates exhibit significant H‐type aggregation. Moreover, Cy‐3COOH/Cu aggregates show about threefold higher photothermal conversion efficiency and obviously enhanced photostability than Cy‐1COOH/Cu and Cy‐2COOH/Cu aggregates. It is demonstrated that H‐aggregates with face‐to‐face π–π stacking greatly quench fluorescence and inhibit singlet oxygen (1O2) production, which lead to the improved photothermal performances. In vitro and in vivo experiments demonstrate the remarkable tumor PTT efficiency of Cy‐3COOH/Cu H‐aggregates. This study provides a new insight into how to precisely control molecular aggregation of organic dyes in supramolecular self‐assembly for enhanced tumor phototherapy.

Isocorrole-Loaded Polymer Nanoparticles for Photothermal Therapy under 980 nm Light Excitation.

Photothermal therapy (PTT) is a promising treatment option for diseases, including cancer, arthritis, and periodontitis. Typical photothermal agents (PTAs) absorb light in the near-infrared (NIR)-I region of 650–900 nm with a predominant focus around 800 nm, as these wavelengths are minimally absorbed by water and blood in the tissue. Recently, interest has grown in developing nanomaterials that offer more efficient photothermal conversion and that can be excited by light close to or within the NIR-II window of 1000–1700 nm, which offers less absorption by melanin. Herein, we report on the development of 5,5-diphenyl isocorrole (5-DPIC) complexes containing either Zn(II) or Pd(II) (Zn[5-DPIC] and Pd[5-DPIC], respectively) that absorb strongly across the 850–1000 nm window. We also show that poly(lactic-co-glycolic acid) (PLGA) nanoparticles loaded with these designer isocorroles exhibit low toxicity toward triple-negative breast cancer (TNBC) cells in the dark but enable efficient heat production and photothermal cell ablation upon excitation with 980 nm light. These materials represent an exciting new platform for 980 nm activated PTT and demonstrate the potential for designer isocorroles to serve as effective PTAs.

Significant effect on the photo conversion performance of non-stoichiometric tungsten oxide with various reaction solvents

Photothermal therapy (PTT) is a new emerging treatment method in recent years which has the advantages of non-invasive and wide adaptability. The key to PTT is the development of effective photothermal agents. Herein, the non-stoichiometric tungsten oxides were prepared in a facile solvothermal method with various reaction solvents (ethanol, n-propanol, isopropanol) and time. The obtained samples were characterized by X-ray diffraction, scanning electron microscopy, transmission electron microscope, photoluminescence and UV–vis–NIR adsorption spectroscopy. The kind of solvent had a significant effect on the phase, microstructure, photo conversion efficiency. Once n-propanol was used as solvent, the samples possessed high crystallinity, uniform fusiform morphology, good dispersibility, obvious absorbance of NIR and the photothermal conversion efficiency of 35.6%. Under the 808 nm near-infrared light irradiation, in vitro cell tests were further conducted on L929 normal and MCF-7 tumor cells for comparative experiments. The outstanding properties make the samples highly potential agents for PTT.

Monitoring Stress Response Difference in Nucleolus Morphology and ATP Content Changes during Hyperthermia Cell Apoptosis with Plasmonic Fluorescent Nanoprobes.

The nucleolus, as a main "cellular stress receptor", is the hub of the stress response driving cancer development and has great research value in the field of organelle-targeting photothermal therapy. However, there are few studies focused on monitoring nucleolar stress response and revealing how the energy metabolism of cells regulates the nucleolar stress response during photothermal therapy. Herein, by designing a nucleolus-targeting and ATP- and photothermal-responsive plasmonic fluorescent nanoprobe (AuNRs-CDs) based on gold nanorods (AuNRs) and fluorescent carbon quantum dots (CDs), we achieved real-time fluorescence imaging of nucleus morphology while monitoring changes of ATP content at the subcellular level. We found that the green fluorescence diminished at 5 min of photothermal therapy, and the nucleolus morphology began to shrink and became smaller in cancerous HepG2 cells. In contrast, there is no significant change of green fluorescence in the nucleolar region of normal HL-7702 cells. ATP content monitoring also showed similar results. Apparently, in response to photothermal stimuli, cancerous cells produce more ATP (energy) along with obvious change in nucleolus morphology and state compared to normal cells under the hyperthermia-induced cell apoptosis. The developed AuNRs-CDs as a nucleolus imaging nanoprobe and effective photothermal agent present promising applications for nucleolar stress studies and targeted photothermal therapy.

Biocompatible Tantalum Nanoparticles as Radiosensitizers for Enhancing Therapy Efficacy in Primary Tumor and Metastatic Sentinel Lymph Nodes.

Metastasis of breast carcinoma is commonly realized through lymphatic circulation, which seriously threatens the lives of breast cancer patients. Therefore, efficient therapy for both primary tumor and metastatic sentinel lymph nodes (SLNs) is highly desired to inhibit cancer growth and metastasis. During breast cancer treatment, radiotherapy (RT) is a common clinical method. However, the efficacy of RT is decreased by the radioresistance to a hypoxic microenvironment and inevitable side effects for healthy issues at high radiation doses. Considering the above-mentioned, we provide high biocompatible poly(vinylpyrrolidone) coated Ta nanoparticles (Ta@PVP NPs) for photothermal therapy (PTT) assisted RT for primary tumor and metastatic SLNs. On the one hand, for primary tumor treatment, Ta@PVP NPs with a high X-ray mass attenuation coefficient (4.30 cm2/kg at 100 keV) can deposit high radiation doses within tumors. On the other hand, for metastatic SLNs treatment, the effective delivery of Ta@PVP NPs from the primary tumor into SLNs is monitored by computed tomography and photoacoustic imaging, which greatly benefit the prognosis and treatment for metastatic SLNs. Moreover, Ta@PVP NPs-mediated PTT could enhance the RT effect, and immunogenic cell death caused by RT/PTT could induce an immune response to improve the therapeutic effect of metastatic SLNs. This study not only explores the potential of Ta@PVP NPs as effective radiosensitizers and photothermal agents for combined RT and PTT but also offers an efficient strategy to cure both primary tumor and metastatic SLNs in breast carcinoma.

Reversing breast cancer bone metastasis by metal organic framework-capped nanotherapeutics via suppressing osteoclastogenesis

Bone metastasis is the major cause of cancer-related morbidity and mortality. To avoid further osteolysis, current treatment ideas focus on tumor cell and the inhibition of osteoclast. Herein, zeolitic imidazolate framework-8–capped Cu2-XSe composite nanoplatform (ICG@Cu2-XSe-ZIF-8) is developed for chemodynamic therapy (CDT) and photothermal therapy (PTT) treatment of malignant breast cancer bone tumors. The rational design of ZIF-8 encapsulation greatly reduces the accumulation of Cu2-XSe to damage the normal cells. Under acidic microenvironment in tumor, ZIF-8 is cleaved to release Cu2-XSe, which can subsequently degrade into Cu (+) and Cu (2+) ions to initiate a Fenton-like reaction inducing CDT. Meanwhile, Cu2-XSe is used to be an effective photothermal transduction agent for exerting the PTT effect. What's more, the selenium element in Cu2-XSe can regulates selenoprotein to inhibit tumor cells and osteoclasts. Of note, the hyperthermia induced by PTT can further enhance the CDT effect in tumor, achieving a synergistic PTT/CDT effect. Based on these advantages, ICG@Cu2-XSe-ZIF-8 effectively suppresses the tumor cells in bone tissue, and reduces the erosion of bone tissue via suppressing osteoclastogenesis. In conclusion, this study demonstrates the potential action mechanism of ZIF-8–capped nanomedicine against osteolysis in bone metastasis.

Conjugated/nonconjugated alternating copolymers for enhanced NIR-II fluorescence imaging and NIR-II photothermal-ferrotherapy.

Conjugated polymers hold great promise for NIR-II fluorescence imaging (FI)-guided NIR-II photothermal therapy (PTT) due to the advantages of easy modification of chemical structures and adjustable NIR absorption. However, to make use of these advantages, it is of paramount importance to formulate conjugated polymers with excellent solubility in organic solution, great NIR-II photothermal conversion efficiency, and high NIR-II fluorescence quantum yield. Herein, a new class of conjugated/nonconjugated alternating copolymers (CNACPs) is reported by introducing nonconjugated linkers into a conjugated backbone to modulate the extinction coefficient at 1064 nm and NIR-II fluorescence quantum yield. The NIR-II absorption, NIR-II emission, and NIR-II photothermal properties of the new CNACPs were studied. Interestingly, it is observed that longer nonconjugated linkers in CNACPs result in higher NIR-II fluorescence intensity with sufficient NIR-II absorption and NIR-II photothermal ability. With these newly developed CNACPs (BBT-C6), phototheranostic nanoparticles (BBTD6/Fe@PMA) are prepared through facile nanoprecipitation using PMA-AD-PEG as an iron ion chelator for NIR-II FI-guided NIR-II PTT/ferrotherapy synergistic therapy. In vitro and in vivo, BBTD6/Fe@PMA effectively inhibited 4T1 cells and tumor progression under 1064 nm laser irradiation. Consequently, this work provides new CNACPs by incorporating nonconjugated linkers into a conjugated backbone to design more effective NIR-II fluorescence imaging and NIR-II photothermal therapy agents.

Injectable and Temperature-Sensitive Titanium Carbide-Loaded Hydrogel System for Photothermal Therapy of Breast Cancer.

Recently, organic–inorganic hybrid materials have gained much attention as effective photothermal agents for cancer treatment. In this study, Pluronic F127 hydrogel-coated titanium carbide (Ti3C2) nanoparticles were utilized as an injectable photothermal agent. The advantages of these nanoparticles are their green synthesis and excellent photothermal efficiency. In this system, lasers were mainly used to irradiate Ti3C2 nanoparticles to produce a constant high temperature, which damaged cancer cells. The nanoparticles were found to be stable during storage at low temperatures for at least 2 weeks. The Ti3C2 nanoparticles exhibited a shuttle-shaped structure, and the hydrogels presented a loosely meshed structure. In addition, Ti3C2 nanoparticles did not affect the reversible temperature sensitivity of the gel, and the hydrogel did not affect the photothermal properties of Ti3C2 nanoparticles. The in vitro and in vivo results show that this hydrogel system can effectively inhibit tumor growth upon exposure to near-infrared irradiation with excellent biocompatibility and biosafety. The photothermal agent-embedded hydrogel is a promising photothermal therapeutic strategy for cancer treatment by enhancing the retention in vivo and elevating the local temperature in tumors.

Structure-controlled lignin complex for PLA composites with outstanding antibacterial, fluorescent and photothermal conversion properties

Polylactic acid (PLA) is increasingly being considered as an ideal biodegradable candidate to replace petroleum-based polymers. However, its practical applications are often hampered by the poor mechanical robustness and solo functionality. Herein, based on the mechanical property improvement of PLA we proposed a simple process of assembling lignin-hybridized modifier and PLA matrix, as opposed to the traditional trade-off between mechanical strength and functionality, while anchoring a biofluorescent moiety onto lignin surfaces. Specifically, the fluorophore group could act as interfacial compatibilizer of complex and facilitate the shape-tailored hybrids for promoting functionality flexibility. With the bimetallic hetero-particles, the preferable lignin-assembled complex could be controllably configured as an antibacterial, fluorophore and photothermal agent. Thus, mechanical enhancement, fluorescence introduction and favorable photothermal ability of the resulting PLA composites were successfully achieved for integrated unification of structural robustness, geometric integrity and functional multiplicity, which was never seen in the other reports. The results showed that PLA composites containing 5 wt% modified lignin, 10 wt% zinc oxide, and 5 wt% silver presented excellent mechanical, fluorescent, photothermal conversion properties. By controlling the ZnO content and morphology, strong inhibition of Escherichia coli (Gram-negative) than that of Staphylococcus Aureus (Gram-positive) was also observed. The flake-shaped ZnO /Ag hybrids contributed to better overall performance of PLA composites than the rod-shaped ZnO/Ag. In this work we developed a facile strategy to assemble a bioderived fluorophore with lignin particles for constructing a structure-controlled complex as a multitasking modifier, featuring mechanical unity and functional adaptability. Specifically, the lignin reinforcement and bimetallic hybrids with different morphologies were explored as an effective fluorophore, antibacterial and photothermal agent. Through multiple dehydration reactions, a conjugating fluorophore was successfully grafted on lignin surfaces to serve as an interface modifier without physical changing its structural robustness. And morphology-tailored hybrid was advantageously immobilized on predefined hetero-particle carrier of fluorescent lignin and endowed composites with desirable antimicrobial properties. The developed strategy would expand the functional applications of PLA materials in food packaging, biopharmaceuticals and simple fluorescent anti-counterfeiting.