Multifunctional hydrogel platform for biofilm scavenging and O2 generating with photothermal effect on diabetic chronic wound healing

Diabetic wound treatment remains a major challenge due to the difficulties of eliminating bacterial biofilm and relieving wound hypoxia. To address these issues simultaneously, a multifunctional Dex-SA-AEMA/MnO₂/PDA (DSAMP) hydrogel platform was developed with excellent biocompatibility and porous structure. The hydrogel could absorb the exudate, maintain humidity and permeate oxygen, which was prepared by encapsulating polydopamine (PDA) and manganese dioxide (MnO₂) into Dex-SA-AEMA (DSA) hydrogel by UV irradiation. With the addition of PDA, the DSAMP hydrogel was proved to eliminate the biofilm after NIR photodynamic therapy (PTT, 808 nm) irradiation at 54 °C. Furthermore, in order to mitigate hypoxia wound microenvironment, MnO₂ nanoparticles were added to convert the endogenous hydrogen peroxide (H₂O₂) into oxygen (O₂, 16 mg L^-1). The diabetic wound in vivo treated by DSAMP hydrogel was completely healed on 14 days. It was revealed that the DSAMP hydrogel possessed a great potential as dressing for diabetic chronic wound healing.

Photothermal card reader assay using the commercial colloidal gold test strip for the rapid quantitative detection of food hazards

The simple and rapid commercial colloidal gold test strip can only be used for qualitative or semi-quantitative detection, accompanied by weak detectability and false negative experimental results. Herein, a photothermal test strip assay which combined test strip with a portable photothermal card reader was established to achieve quantitative detection with excellent detectability. According to the photothermal effect produced by gold nanoparticles (GNPs) captured on the test line, the signal could be recorded by the reader. Thirteen food hazards including veterinary drug residues and pesticide residues were tested; the photothermal detectability in actual samples were about 23 (methyl parathion), 7 (enrofloxacin), 6 (sarafloxacin), 8 (sulfadiazine), 12 (sulfamethazine), 7 (paraquat), 6 (malachite green), 11 (amantadine), 13 (nitrofurazone), 6 (diethylstilbestrol), 12 (estriol), 21 (estrone), and 26 (17β-estradiol) times better than the visual detectability. Our results demonstrated that the photothermal test strip assay could be used for sensitive, rapid, and quantitative detection of residues of food hazards.

Synergistic photodynamic/photothermal bacterial inactivation over heterogeneous quaternized chitosan/silver/cobalt phosphide nanocomposites

Globally, drug-resistant bacteria are a potential threat to human society owing to the overuse of antibiotics and thus, non-antibiotic bactericides are urgently needed. Herein, an innovative antibacterial nanoplatform based on quaternized chitosan (QCS)/ silver (Ag)/ cobalt phosphide (CoP) nanocomposites is envisaged for achieving near-infrared (NIR) laser-inducible rapid sterilisation. In the core-shell hybrids, Ag nanoparticles (NPs) with a size of ∼ 25 nm were uniformly deposited on CoP nanoneedles, upon which a layer of QCS (approximately 10 wt%), is coated. Numerical calculations revealed that under NIR irradiation, high-energy hot electrons arising from the surface plasmon resonance effect of Ag migrate into the interface between Ag and CoP, and amplify the photothermal effect of CoP. Meanwhile, photo-excited electrons from CoP are transported onto Ag NPs because the Schottky heterostructure facilitates the production of reactive oxygen species. Ag loading simultaneously enhances the photocatalytic and photothermal effects of CoP, achieving rapid antibacterial activity synergistically. The QCS coating improves the dispersibility of power in an aqueous system and provides contact between the antiseptics and bacteria. The ternary QCS/Ag/CoP nanocomposites achieved greater than 99.6% inactivation against S. aureus and E. coli within 10 min. In addition, the nanocomposites were confirmed to be noncytotoxic to mammals. Consequently, the QCS/Ag/CoP nanoplatforms possess great potential for rapid and effective antibacterial applications.

Coupling solar-driven photothermal effect into photocatalysis for sustainable water treatment

Effectively harnessing renewable and inexhaustible solar radiation for energy conversion has attracted significant research interest in the past decade. Solar thermal conversion, as a ubiquitous phenomenon, can be implemented to evaporate water and concurrently boost photocatalytic performance for addressing freshwater scarcity and energy crisis. Most recently, solar water evaporation accompanied by photocatalytic degradation, sterilization, and hydrogen production has been proposed as a promising avenue to endow new vitality into the field of clean water and energy production. Driven by the advances of rationally designed solar-powered functional materials, a large variety of photothermal-coupled photocatalysis technologies have been exploited. In this context, it is imperative to summarize the recent progress and discuss the challenges in this multidisciplinary field. Herein, we overview photothermal materials based on various fundamental principles and highlight emerging applications in the areas of solar water evaporation, water purification, and solar-driven energy production. Furthermore, the challenges and perspectives toward both fundamental research and practical applications are also proposed. It is envisioned that this review can provide insightful suggestions to further advance the development of integrated solar thermal driven water evaporation and photocatalytic systems to fulfill concurrent energy conversion and environmental applications.

Multifunctional and thermoresponsive methylcellulose composite hydrogels with photothermal effect

Multifunctional and thermoresponsive hydrogels can be used as soft materials in various medical applications, such as beauty devices, drug delivery, and near-infrared (NIR) lasers. In this study, methylcellulose (MC) composite hydrogels containing tannic acid (TA) and Fe³⁺ were prepared via a simple, fast process. The MC composite hydrogel contains hydrogen bonds between the MC polymer and TA and coordination bonds between TA and Fe³⁺, without losing the reversible thermogelation properties of the MC polymer. The gelation rates and mechanical properties of the MC composite hydrogel were controlled by varying its TA and Fe³⁺ contents. In particular, the hydrogel with a TA-Fe chelating complex showed an excellent photothermal effect, indicating its potential application in cosmetic beauty devices. It also exhibited UV-blocking, antioxidant, and antibacterial properties owing to the multifunctional TA. The facile processing of these MC/TA/Fe hydrogels provides new opportunities for biomedical applications and beauty devices employing NIR laser therapy.

Novel Ti3C2Tx MXene wrapped wood sponges for fast cleanup of crude oil spills by outstanding Joule heating and photothermal effect

Remediation of crude oil spills is a great challenge owing to the poor mobility and high viscosity of crude oil. Herein, a porous polydimethylsiloxane@wood sponge/MXene (PDMS@WSM) with outstanding compressibility and hydrophobic/lipophilic ability was demonstrated as crude oil absorbent. The surface temperature of PDMS@WSM could quickly rise to 80 °C with a working voltage of 4 V and to 66 °C under simulated sunlight irradiation of 1.5 KW m^-2, respectively. Due to the excellent Joule heating and photothermal conversion effect, the PDMS@WSM displayed maximum adsorption capacity of 11.2×10⁵ g m^-3 within 6 min. The PDMS@WSM showed preferable reusability and cycle stability because of its brilliant compressibility. Moreover, the oil-collecting device based on PDMS@WSM could continuously collect crude oil spills, achieving an active collection of 25 mL crude oil within 150 s. Therefore, the porous PDMS@WSM absorbent exhibited great potential for crude oil spills remediation, energy regulation, and desalination of hypersaline water.

AuAg nanocages/graphdiyne for rapid elimination and detection of trace pathogenic bacteria

We prepared a biocompatible AuAg nanocages/graphdiyne @ polyethylene glycol (AuAg/GDY@PEG) composite. The combination of AuAg and GDY to obtain a synergistically enhanced photothermal effect, and the antibacterial effect of GDY and AuAg are used in combined anti-infective therapy. The in vitro antibacterial activity of AuAg/GDY@PEG was investigated, showing an impressive broad-spectrum antibacterial activity with the killing rate > 99.999%. Based on the photothermal conversion ability of AuAg/GDY@PEG, a simple photothermal immunoassay for pathogenic bacteria was successfully established. Sandwich immune response was performed on a microporous plate, the microplate containing the antibody binds specifically to the bacterium being tested, which then binds to the material with the antibody on its surface, and the signal was a change in temperature under 808 nm near-infrared light. The limit of detection (LOD) for S. typhimurium detection is 10³ CFU mL^-1, with a range of 10³-10⁷ CFU mL^-1. This method is accurate, rapid and low-cost, which can be used for on-site detection of pathogenic bacteria in food.

Biocompatible BSA-Ag2S nanoparticles for photothermal therapy of cancer

Photothermal therapy (PTT) induced by near-infrared (NIR) laser has attracted much attention for the innovation of tumor therapy, in which the photothermal agent with good biocompatibility and high efficiency is the prerequisite. Herein, the biocompatible bovine serum albumin (BSA) coated Ag₂S nanoparticles (NPs) as photothermal agent were synthesized directly at mild temperature for PTT of cancer. The high photothermal conversion efficiency of the obtained Ag₂S NPs with strong NIR absorption is about 18.89%, which make them ideal materials for photothermal agents. Furthermore, the Ag₂S NPs can induce effective apoptosis of tumor cells exposed to an NIR laser (808 nm), realizing an effective PTT with excellent killing effect of tumor cells. This work provides a simple reproducible method to fabricate the water-soluble and biocompatible Ag₂S NPs, which would provide new insights of designing new functional NPs for the PTT therapy of tumor.

Photothermal-enhanced peroxidase-like activity of CDs/PBNPs for the detection of Fe3+ and cholesterol in serum samples

Carbon dots/Prussian blue nanoparticles (CDs/PBNPs) with fluorescence (FL) performance and peroxidase-like activity are synthesized by a simple two-step method. The FL of CDs/PBNPs can be effectively quenched by Fe³⁺. Fe³⁺ can accelerate the peroxidase-like activity of CDs/PBNPs. More excitingly, the peroxidase-like activity of CDs/PBNPs could be further enhanced due to the influence of the photothermal effect. Based on the FL property and enhanced peroxidase-like activity, a cascade strategy is proposed for detection of Fe³⁺ and free cholesterol. CD/PBNPs act as FL probe for detection of Fe³⁺. The enhanced peroxidase-like activity of CDs/PBNPs can also be used as colorimetric probe for the detection of free cholesterol. The detection ranges of Fe³⁺ and free cholesterol are 4-128 μM and 2-39 μM, and the corresponding limit of detections are 2.0 μM and 1.63 μM, respectively. The proposed strategy has been verified by the feasibility determination of Fe³⁺ and free cholesterol, suggesting its potential in the prediction of disease.

Specific recognition and photothermal release of circulating tumor cells using near-infrared light-responsive 2D MXene nanosheets@hydrogel membranes

2D materials with attractive optical properties are promising for individualized cancer immunotherapy. Isolation, capture, and release of circulating tumor cells (CTCs) are of great significance for promoting the process of early diagnosis of cancers. MXene nanosheets incorporated gelatin hydrogel offers the possibility of achieving near-infrared (NIR) light response to initiate the photothermal effect. Herein, the design and preparation of Ti₃C₂T_x MXene nanosheets-embedded thermoresponsive gelatin hydrogel membrane with NIR light-responsive for the specific capture and release of CTCs were reported. The membrane was fabricated by casting Ti₃C₂T_x-embedded gelatin onto a substrate and then modified with epithelial-cell adhesion-molecule antibody (anti-EpCAM) for the specific recognition and separation of CTCs from whole blood. The captured cells can be released without damage with dual-mode containing temperature-responsive release (gelatin deconstructed at 37 °C) and photothermal site-release (Ti₃C₂T_x induced by NIR light). Furthermore, we were able to achieve an average efficient release rate of 89 % of captured cells with stable cell viability of 87 % via the NIR light irradiation. This work may provide the promising potential for retrieval of single cells in clinical diagnosis.

Near-infrared light triggered multi-hit therapeutic nanosystem for tumor specific photothermal effect amplified signal pathway regulation and ferroptosis

The high therapeutic resistance of tumor is the primary cause behind tumor recurrence and incurability. In recent years, scientists have devoted themselves to find a variety of treatments to solve this problem. Herein, we propose a multi-hit strategy that is based on the biodegradable hollow mesoporous Prussian blue (HMPB)-based nanosystem for tumor-specific therapy that encapsulated the critical heat shock protein 90 (HSP90) inhibitor 17-dimethylamino-ethylamino-17-demethoxydeldanamycin (17-DMAG). The nanosystem was further modified using thermotropic phase transition material star-PEG-PCL (sPP) and hyaluronic acid (HA), which offers near infrared light (NIR) responsive release characteristic, as well as enhanced tumor cell endocytosis. Upon cell internalization of 17-DMAG-HMPB@sPP@HA and under 808 nm laser irradiation, photothermal-conversion effect of HMPB directly kills cells using hyperthermia, which further causes phase transition of sPP to trigger release of 17-DMAG, inhibits HSP90 activity and blocks multiple signaling pathways, including cell cycle, Akt and HIF pathways. Additionally, the down-regulation of GPX4 protein expression by 17-DMAG and the release of ferric and ferrous ions from gradual degradation of HMPB in the endogenous mild acidic microenvironment in tumors promoted the occurrence of ferroptosis. Importantly, the antitumor effect of 17-DMAG and ferroptosis damage were amplified using photothermal effect of HMPB by accelerating release of ferric and ferrous ions, and reducing HSP90 expression in cells, which induced powerful antitumor effect in vitro and in vivo. This multi-hit therapeutic nanosystem helps provide a novel perspective for solving the predicament of cancer treatment, as well as a promising strategy for design of a novel cancer treatment nanoplatform.

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The tumor specific multi-hit therapeutic nanosystem was constructed.

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The nanosystem exerts anti-tumor effect includes photothermal effect, cell signaling pathway regulation and ferroptosis.

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The synergistic 17-DMAG-HMPB@sPP@HA nanosystem offers a promising strategy for effective tumor therapies.

Synergistic photothermal cancer immunotherapy by Cas9 ribonucleoprotein-based copper sulfide nanotherapeutic platform targeting PTPN2

Photothermal therapy (PTT) is a promising strategy for the treatment of advanced malignant neoplasm. However, the anti-tumor efficacy by PTT alone is insufficient to control tumor growth and metastasis. Here, we report a multifunctional nanotherapeutic system exerting a combined PTT and immunotherapy to synergistically enhance the therapeutic effect on melanoma. In particular, we selected the semiconductor nanomaterial copper sulfide (CuS), which served not only as a near-infrared (NIR) light-triggered photothermal converter for tumor hyperthermia but as a basic carrier to modify Cas9 ribonucleoprotein targeting PTPN2 on its surface. Efficient PTPN2 depletion was observed after the treatment of CuS-RNP@PEI nanoparticles, which caused the accumulation of intratumoral infiltrating CD8 T lymphocytes in tumor-bearing mice and upregulated the expression levels of IFN-ᵧ and TNF-α in tumor tissue, thus sensitizing tumors to immunotherapy. In addition, the effect worked synergistically with tumor ablation and immunogenic cell death (ICD) induced by PTT to amplify anti-tumor efficacy. Taken together, this exogenously controlled method provides a simple and effective treatment option for advanced malignant neoplasm.

Construction of a photothermal hydrogel platform with two-dimensional PEG@zirconium-ferrocene MOF nanozymes for rapid tissue repair of bacteria-infected wounds

Because of increasing antibiotic resistance, careful construction of an efficient phototherm-nanozyme-hydrogel synergistic antibacterial platform is imperative for the treatment of bacteria-infected wounds. In this study, a carrageenan-based hydrogel embedded with polyethylene glycol dicarboxylic acid (COOH-PEG-COOH)-functionalized zirconium-ferrocene metal-organic frames nanosheets (PEG@Zr-Fc MOF hydrogel) was successfully constructed through COOH-PEG-COOH modification and physical assembly. The PEG@Zr-Fc MOF hydrogel could capture Gram-negative (Escherichia coli) and Gram-positive (Staphylococcus aureus) bacteria through reactive oxygen species (ROS) destruction and kill some bacteria by disintegration of H₂O₂ into toxic hydroxyl radicals (•OH). Significantly, by introducing the photothermal performance of the PEG@Zr-Fc MOF hydrogel, the catalytic activity of the target material could be improved to achieve a synergistic sterilization effect. The wound infection model experiment confirmed that the PEG@Zr-Fc MOF hydrogel had powerful bactericidal activity and could achieve a rapid tissue repair effect. More importantly, the PEG@Zr-Fc MOF hydrogel had negligible biological toxicity and reduced the risk of inflammation. This study reveals that phototherm-nanozyme-hydrogel synergy holds great potential for bacterial wound infection therapy. Additionally, this is the first study to use two-dimensional MOF nanozymes in combination with hydrogel for antimicrobial therapy. STATEMENT OF SIGNIFICANCE: Bacteria-infected wound is one of the serious threats to public health, and this topic has attracted tremendous attention worldwide in recent decades. Although numerous traditional therapeutic strategies that depend on antibiotics have been developed and applied for treating bacteria-infected wound disease, the effect of wound treatment is becoming increasingly unsatisfactory due to bacterial resistance. The present study provides a feasible method to treat bacterial wound infection by constructing a carrageenan-based hydrogel embedded with polyethylene glycol dicarboxylic acid (COOH-PEG-COOH) functionalized zirconium-ferrocene metal organic frame nanosheets (PEG@Zr-Fc MOF hydrogel). The experiments with the wound infection model confirmed that the PEG@Zr-Fc MOF hydrogel had powerful bactericidal activity and could achieve a rapid tissue repair. This strategy provides a promising avenue to further accelerate the development of antibacterial therapy in biomedical fields.

Copper sulfide with morphology-dependent photodynamic and photothermal antibacterial activities

Metal chalcogenides have been intensively investigated as antibacterial agents due to their unique structures and superior photoactivities. Herein, various structures of copper sulfide (CuS), a metal chalcogenide, such as microspheres (MSs), nanosheets (NSs), and nanoparticles (NPs), were developed in this work for antibacterial applications. A hydrothermal process was utilized to synthesize CuS MSs, CuS NSs, and CuS NPs. Under simulated solar light and near-infrared (NIR) light irradiation, the antibacterial behaviors, reactive oxygen species (ROS) production, and light-driven antibacterial mechanisms of CuS MSs, CuS NSs, and CuS NPs were demonstrated with the bacterium Escherichia coli (E. coli). Bacterial growth curves and ROS generation tests indicated that CuS NSs and CuS NPs had higher light-driven antibacterial activities than that of CuS MSs. ROS of hydroxyl (·OH) and superoxide anion radicals (O₂^-) were investigated via an electron spin resonance (ESR) spectroscopic analysis by respectively incubating CuS MSs, CuS NSs, and CuS NPs with E. coli under simulated solar light irradiation. Furthermore, E. coli incubated with CuS NPs and CuS NSs showed substantial bacterial degradation after NIR laser irradiation, which was attributed to their photothermal killing effects. Light-driven antibacterial mechanisms of CuS NSs and CuS NPs were investigated, and we discovered that under simulated solar and NIR light irradiation, CuS NSs and CuS NPs produced photoinduced electrons, and the copper ions and photoinduced electrons then reacted with atmospheric moisture to produce hydroxide and superoxide anion radicals and heat, resulting in bacterial mortality.

Hollow Core-Shell potassium Phosphomolybdate@Cadmium Sulfide@Bismuth sulfide Z-Scheme tandem heterojunctions toward optimized Photothermal-Photocatalytic performance

A hollow core-shell potassium phosphomolybdate (KMoP)@cadmium sulfide (CdS)@bismuth sulfide (Bi₂S₃) Z-scheme tandem heterojunction is fabricated by a simple hydrothermal strategy and kept in a water bath to continue the reaction. At the same time, the ternary structure combined Keggin-type polyoxometalate with two photosensitive sulfide semiconductors to form a stable hollow core-shell heterojunction. KMoP@CdS@Bi₂S₃ with a narrow band gap of ∼ 1.2 eV also has excellent photothermal performance, which may further promote photocatalytic efficiency. The hollow core-shell KMoP@CdS@Bi₂S₃ tandem heterojunction shows excellent H₂ production performance, Cr^VI reduction ability and photocatalytic degradation performance of highly toxic tetracycline (TC). Under visible light irradiation, the photocatalytic H₂ generation rate of the KMoP@CdS@Bi₂S₃ tandem heterojunction reaches 831 μmol h^-1, which is 103 times higher than that of pristine KMoP. The photocatalytic reduction efficiency of Cr^VI and degradation efficiency of TC are as high as 95.5 and 97.51%, ∼4 times higher than that of KMoP. The boosted photocatalytic performance can be ascribed to the formation of core-shell Z-scheme tandem heterojunctions favoring spatial charge separation and the narrow band gap, which extends the photoresponse to visible light/NIR regions. When TC and Cr^VI exist at the same time, the reduction efficiency of Cr^VI can be as high as 99.64% because the intermediate of TC degradation can promote the reduction of Cr^VI. In addition, the photocatalytic performance of the KMoP@CdS@Bi₂S₃ heterojunction remains nearly constant after 4 recycles, which indicates high stability. The design strategy may provide new insights for preparing other high-performance core-shell tandem heterojunction photocatalysts for solar energy conversion.

Nanomaterials-assisted thermally induced neuromodulation

Neuromodulation, as a fast-growing technique in neuroscience, has been a great tool in investigation of the neural pathways and treatments for various neurological disorders. However, the limitations such as constricted penetration depth, low temporal resolution and low spatial resolution hindered the development and clinical application of this technique. Nanotechnology, which refers to the technology that deals with dimension under 100 nm, has greatly influenced the direction of scientific researches within recent years. With the recent advancements in nanotechnology, much attention is being given at applying nanomaterials to address the limitations of the current available techniques in the field of biomedical science including neuromodulation. This mini-review aims to introduce the current state-of-the-art stimuli-responsive nanomaterials used for assisting thermally induced neuromodulation.

NIR-II reinforced intracellular cyclic reaction to enhance chemodynamic therapy with abundant H2O2 supply

Chemodynamic therapy (CDT) is an ideal therapeutic modality with endogenous H₂O₂ as stimulus. Most intracellular H₂O₂ supplement strategies for improving CDT efficiency are strongly rely on oxygen participation, and the hypoxia tumor microenvironment impairs their performance. Here we develop a self-assembled metal-organic coordinated nanoparticle Cu-OCNP/Lap with NIR-II reinforced intracellular cyclic reaction to enhance CDT efficiency. Cu-OCNP/Lap is synthesized using Cu²⁺ as nodes and 1,4,5,8-tetrahydroxyanthraquinone (THQ) and banoxantrone dihydrochloride (AQ4N) as ligands, with β-lapachone (β-Lap) loading to conduct intracellular cyclic reaction. Cu-OCNP/Lap has good photothermal effect at NIR-II window, and the corresponding local temperature increase speeds blood flow and supplies sufficient oxygen at tumor site to reinforce β-Lap cyclic reaction with abundant H₂O₂ generation. Cu⁺ is released from Cu-OCNP/Lap in response to glutathione (GSH) and triggers CDT. Sufficient intracellular H₂O₂ supply enhances CDT effect and demonstrates good suppressions for tumor growth. This design offers a promising strategy to enhance CDT efficiency.

Diffraction-based label-free photothermal detector for separation analyses in a nanocapillary

Miniaturization of column diameter in liquid chromatography is one of the major trends in separation sciences toward single-cell proteomics and metabolomics. Micro/nanoscale open tubular (OT) capillaries are promising tools for efficient separation analyses of the ultra-small volume of samples. However, highly sensitive and label-free on-column detection is still challenging for such ultra-small capillaries. In this study, we developed a photothermal detector using optical diffraction phenomena by a single nanocapillary. Our detection method realized concentration determination of unlabeled sample solutions in a nanocapillary with 460 nm inner diameter. The calculated limit of detection was 0.12 µM, which corresponds to 16 molecules in a detection volume of 0.23 fL. Furthermore, normal-phase chromatography was performed on a 12 cm long nanocapillary, and femtoliter sample injection, efficient separation, and label-free detection of dye molecules were demonstrated. Our photothermal detector will be widely used as a universal tool for chemical/biological analyses using capillaries with micro/nanoscale diameters.

Recoverable peroxidase-like Fe3O4@MoS2-Ag nanozyme with enhanced antibacterial ability

Antibacterial agents with enzyme-like properties and bacteria-binding ability have provided an alternative method to efficiently disinfect drug-resistance microorganism. Herein, a Fe₃O₄@MoS₂-Ag nanozyme with defect-rich rough surface was constructed by a simple hydrothermal method and in-situ photodeposition of Ag nanoparticles. The nanozyme exhibited good antibacterial performance against E. coli (~69.4%) by the generated ROS and released Ag⁺, while the nanozyme could further achieve an excellent synergistic disinfection (~100%) by combining with the near-infrared photothermal property of Fe₃O₄@MoS₂-Ag. The antibacterial mechanism study showed that the antibacterial process was determined by the collaborative work of peroxidase-like activity, photothermal effect and leakage of Ag⁺. The defect-rich rough surface of MoS₂ layers facilitated the capture of bacteria, which enhanced the accurate and rapid attack of •OH and Ag⁺ to the membrane of E. coli with the assistance of local hyperthermia. This method showed broad-spectrum antibacterial performance against Gram-negative bacteria, Gram-positive bacteria, drug-resistant bacteria and fungal bacteria. Meanwhile, the magnetism of Fe₃O₄ was used to recycle the nanozyme. This work showed great potential of engineered nanozymes for efficient disinfection treatment.

Recoverable peroxidase-like Fe3O4@MoS2-Ag nanozyme with enhanced antibacterial ability

Antibacterial agents with enzyme-like properties and bacteria-binding ability have provided an alternative method to efficiently disinfect drug-resistance microorganism. Herein, a Fe₃O₄@MoS₂-Ag nanozyme with defect-rich rough surface was constructed by a simple hydrothermal method and in-situ photodeposition of Ag nanoparticles. The nanozyme exhibited good antibacterial performance against E. coli (~69.4%) by the generated ROS and released Ag⁺, while the nanozyme could further achieve an excellent synergistic disinfection (~100%) by combining with the near-infrared photothermal property of Fe₃O₄@MoS₂-Ag. The antibacterial mechanism study showed that the antibacterial process was determined by the collaborative work of peroxidase-like activity, photothermal effect and leakage of Ag⁺. The defect-rich rough surface of MoS₂ layers facilitated the capture of bacteria, which enhanced the accurate and rapid attack of •OH and Ag⁺ to the membrane of E. coli with the assistance of local hyperthermia. This method showed broad-spectrum antibacterial performance against Gram-negative bacteria, Gram-positive bacteria, drug-resistant bacteria and fungal bacteria. Meanwhile, the magnetism of Fe₃O₄ was used to recycle the nanozyme. This work showed great potential of engineered nanozymes for efficient disinfection treatment.

Recoverable peroxidase-like Fe3O4@MoS2-Ag nanozyme with enhanced antibacterial ability

Antibacterial agents with enzyme-like properties and bacteria-binding ability have provided an alternative method to efficiently disinfect drug-resistance microorganism. Herein, a Fe₃O₄@MoS₂-Ag nanozyme with defect-rich rough surface was constructed by a simple hydrothermal method and in-situ photodeposition of Ag nanoparticles. The nanozyme exhibited good antibacterial performance against E. coli (~69.4%) by the generated ROS and released Ag⁺, while the nanozyme could further achieve an excellent synergistic disinfection (~100%) by combining with the near-infrared photothermal property of Fe₃O₄@MoS₂-Ag. The antibacterial mechanism study showed that the antibacterial process was determined by the collaborative work of peroxidase-like activity, photothermal effect and leakage of Ag⁺. The defect-rich rough surface of MoS₂ layers facilitated the capture of bacteria, which enhanced the accurate and rapid attack of •OH and Ag⁺ to the membrane of E. coli with the assistance of local hyperthermia. This method showed broad-spectrum antibacterial performance against Gram-negative bacteria, Gram-positive bacteria, drug-resistant bacteria and fungal bacteria. Meanwhile, the magnetism of Fe₃O₄ was used to recycle the nanozyme. This work showed great potential of engineered nanozymes for efficient disinfection treatment.

Recoverable peroxidase-like Fe3O4@MoS2-Ag nanozyme with enhanced antibacterial ability

Antibacterial agents with enzyme-like properties and bacteria-binding ability have provided an alternative method to efficiently disinfect drug-resistance microorganism. Herein, a Fe₃O₄@MoS₂-Ag nanozyme with defect-rich rough surface was constructed by a simple hydrothermal method and in-situ photodeposition of Ag nanoparticles. The nanozyme exhibited good antibacterial performance against E. coli (~69.4%) by the generated ROS and released Ag⁺, while the nanozyme could further achieve an excellent synergistic disinfection (~100%) by combining with the near-infrared photothermal property of Fe₃O₄@MoS₂-Ag. The antibacterial mechanism study showed that the antibacterial process was determined by the collaborative work of peroxidase-like activity, photothermal effect and leakage of Ag⁺. The defect-rich rough surface of MoS₂ layers facilitated the capture of bacteria, which enhanced the accurate and rapid attack of •OH and Ag⁺ to the membrane of E. coli with the assistance of local hyperthermia. This method showed broad-spectrum antibacterial performance against Gram-negative bacteria, Gram-positive bacteria, drug-resistant bacteria and fungal bacteria. Meanwhile, the magnetism of Fe₃O₄ was used to recycle the nanozyme. This work showed great potential of engineered nanozymes for efficient disinfection treatment.

Convenient detection of H2S based on the photothermal effect of Au@Ag nanocubes using a handheld thermometer as readout

Hydrogen sulfide (H₂S), as a hazardous gas, is often found around dump areas. Long term exposure can cause harm to health, it is highly necessary to develop some simple and sensitive methods for on-site H₂S detection. Herein, a convenient photothermal assay has been designed for the quantitation of H₂S using a handheld thermometer as readout. Au@Ag nanocubes (Au@Ag NCs), a core-shell nanocomposite with strong light absorption at ∼450 nm, was chosen as a novel photothermal agent in this study. Under the laser irradiation at 450 nm, the Au@Ag NCs show a strong photothermal effect, and a significant temperature enhancement can be measured by the thermometer easily. The presence of H₂S can lead to the deposition of sulfur onto Au@Ag NCs, altering the localized surface plasmon resonance absorption, size, surface composition, and morphology of Au@Ag NCs and hence leading to the reduction of photothermal effect. The change of the temperature has a linear relationship with the H₂S concentration in the range of 0.5-80.0 μM with a detection limit of 0.35 μM. By combining with simple sample purification procedures, the developed method has been applied to detect H₂S in garbage odor gas with satisfactory results.

Photothermal-triggered system for oligonucleotides delivery from cationic gold nanorods surface: A molecular dynamic investigation

Bioconjugate gold-based nanostructures combining the plasmonic photothermal effect with photothermal-triggered DNA delivery are appealing materials for medical diagnostic and therapy for cell-based disease. In this study, we demonstrate the use of surface hybridization to prepare DNA-modified gold nanorods to be used as photo-delivery system for single stranded oligonucleotides. The as prepared DNA modified gold nanorods have strong absorption bands in the visible and near-infrared regions in which the absorbed light through photothermal effect, induces a surface temperature increasing up to the melting temperature with consequent DNA release. No evident DNA release was observed below the melting temperature. The experimental data were supported by molecular dynamic simulation investigation, showing the kinetics aspect of dsDNA de-hybridization at gold nanorods surface at temperature below (298 K) and above (333 K) the melting temperature of sequence investigated. We demonstrate that the cationic charges of surfactant, localized at nanorods surface, induce a remarkable de-hybridization of strands DNA, as confirmed by an increasing of hybridization enthalpy value of about 7 kcal/mol and by a faster de-hybridization process, respect the model of gold nanorods without positive charges. These data were corroborated by the increasing of the root mean square deviation value (about 4.4 Å, calculated at 333 K) indicating that the presence of cationic headgroup at gold surface induce separation of the double strand. This finding data paving the way for the development of nanostructured material for photothermal-triggered delivery systems of DNA for gene therapy application.

Portable and quantitative detection of carbendazim based on the readout of a thermometer

The detection of carbendazim (CBZ) is important for food safety and human health. However, most current analytical methods require large instruments and highly trained operators. In order to solve this problem, herein, an innovative portable and quantitative photothermal assay platform relying on a thermometer readout for the detection of CBZ has been developed. Gold nanoparticles (AuNPs), which exhibit a strong distance-dependent photothermal effect under specific laser irradiation, were utilized as indicators. The CBZ aptamer was introduced to protect AuNPs from salt-mediated aggregation. When CBZ is present, the binding event between CBZ and aptamer leads to the loss of the aptamer protective effect on AuNPs, and AuNP aggregation occurs. Under 650-nm laser irradiation, the increase in temperature associated with an AuNP-dependent photothermal effect is highly related to the CBZ concentration. Having the advantages of user-friendliness, low cost, quick response, and portability, this method has great potential for on-site applications.

Application of M1 macrophage as a live vector in delivering nanoparticles for in vivo photothermal treatment

Introduction

To enhance photothermal treatment (PTT) efficiency, a delivery method that uses cell vector for nanoparticles (NPs) delivery has drawn attention and studied widely in recent years.

Objectives

In this study, we demonstrated the feasibility of M1 activated macrophage as a live vector for delivering NPs and investigated the effect of NPs loaded M1 stimulated by Lipopolysaccharide on PTT efficiency in vivo.

Methods

M1 was used as a live vector for delivering NPs and further to investigate the effect of NPs loaded M1 on PTT efficiency. Non-activated macrophage (MФ) was stimulated by lipopolysaccharide (LPS) into M1 and assessed for tumor cell phagocytic capacity towards NPs

Results

We found M1 exhibited a 20-fold higher uptake capacity of NPs per cell volume and 2.9-fold more active infiltration into the tumor site, compared with non-activated macrophage MФ. We injected M1 cells peritumorally and observed that these cells penetrated into the tumor mass within 12 h. Then, we conducted PTT using irradiation of a near-infrared laser for 1 min at 1 W/cm². As a result, we confirmed that using M1 as an active live vector led to a more rapid reduction in tumor size within 1 day indicating that the efficacy of PTT with NPs-loaded M1 is higher than that with NPs-loaded MФ.

Conclusion

Our study demonstrated the potential role of M1 as a live vector for enhancing the feasibility of PTT in cancer treatment.

Yolk-shell structured Au nanorods@mesoporous silica for gas bubble driven drug release upon near-infrared light irradiation

Drug release systems co-encapusulated with ammonium bicarbonate (ABC) could facilitate drug release upon acidic or thermal stimulations to improve therapeutic effect. However, it is not easy to control drug release rate, owing to relative stable temperature and acidic condition in living body. Besides, the additional loaded ABC reduces drug loading capacity. Herein, a near-infrared light triggered rapid drug release system with high loading capacity was developed by loading ABC and doxorubicin into yolk-shell structured Au nanorods@mesoporous silica. Gas bubbles were generated from the thermolysis of ABC utilizing photothermal effect of Au nanorods to extrude drug molecules. The mesoporous silica shell was finally destroyed along with growing bubbles, resulting in burst drug release. The photothermal therapeutic effect of Au nanorods also contributed in tumor treatment. The excellent therapeutic effect was demonstrated in cancer cells and tumor-bearing mice, which provides a new reference to achieve controllable rapid drug release in cancer medicine.

A superhydrophobic coating harvesting mechanical robustness, passive anti-icing and active de-icing performances

HYPOTHESIS

Ice accretion is a challenging issue for various residential activities and industrial facilities. However, most of the current anti/de-icing coatings fail to maintain their properties when subject to frequent mechanical wear, and their limited functionality (either anti-icing or de-icing individually) cannot meet the requirement of all-weather utilization.

EXPERIMENTS

Herein, a multifunctional superhydrophobic coating is prepared by compositing ferroferric oxide nanoparticles (Fe₃O₄ NPs) with fluorinated epoxy resin via an inverse infiltration process. The surface composition, morphology and wettability are systematically characterized using Fourier-transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM) coupled with energy dispersive X-ray spectroscopy (EDX), laser scanning microscopy and contact angle tensiometer. The anti-icing and de-icing performances are evaluated by investigating the freezing delay and photothermal effect, respectively.

FINDINGS

This coating shows outstanding water repellency (water contact angle up to 161.0°, sliding angle down to 1.4°) and can maintain superhydrophobicity within 400 cycles of tape peeling, 260 cycles of sandpaper abrasion or 25 cycles of sand impact. Besides, because the hydrophobic nano/micro hierarchical structures tremendously retard the heat transfer, the freezing process of water droplet on this coating can be apparently delayed by up to 35 min as compared to the uncoated substrate. Moreover, owing to the photothermal effect of the Fe₃O₄ NPs, the coating's surface temperature can be rapidly increased above 0 °C under infrared irradiation, which facilitates the ice melting on cold surfaces. Our work offers a versatile approach to address the icing problems in diverse weather conditions, which exhibits great prospects in various engineering applications.

Salmonella typhimurium detector based on the intrinsic peroxidase-like activity and photothermal effect of MoS2

A multimode dot-filtration immunoassay (MDFIA) was established for rapid and accurate detection of the target (Salmonella typhimurium), which was based on the intrinsic color, peroxidase-like activity and photothermal effect of molybdenum disulfide (MoS₂). Obviously, multimode detection can improve detection accuracy compared to the direct visual detection in test strips. A thermal imaging camera was used as detector to record the temperature change (ΔT) of MoS₂ and establish the standard curve of ΔT and the concentration of Salmonella typhimurium to realize quantitative determination. The main parameters that affect the analytical performance of MDFIA were optimized. Under the optimal experimental conditions, the limit of detection (LOD) of photothermal detection reached 10² CFU mL^-1 and was one order of magnitude lower than the limit of direct visual detection and catalytic color development detection (10³ CFU mL^-1). The accuracy and analytical sensitivity were enhanced by intrinsic peroxidase-like activity and the huge photothermal effect of MoS₂. Moreover, this method exhibited high selectivity, good repeatability, and acceptable stability and the entire process was simple to be accomplished in 30 min, which generally meets the need of rapid detection. The successful implementation in real samples with the recovery being between 99.5 and 119.2% showed that it could be used as a promising quality control strategy for detection of other foodborne pathogens. The peroxidase-like activity and excellent photothermal effect of MoS₂ was used to develop a multimode dot-filtration immunoassay for rapid detection of Salmonella typhimurium.

Low-intensity near-infrared light-triggered spatiotemporal antibiotics release and hyperthermia by natural polysaccharide-based hybrid hydrogel for synergistic wound disinfection

Photothermal sterilization is a promising and effective treatment method in treating bacterial infection. Generally, a widely employed light source in photothermal sterilization inevitably damages the skin tissue due to the high-intensity irradiation dose. How to provide useful antibacterial outcomes without light-triggered skin damage is a challenge for photothermal sterilization. In this work, a novel antibacterial hydrogel (VAT hydrogel, the abbreviation for vancomycin-agarose-ferric tannate hydrogel) has been successfully constructed by the natural polysaccharide hydrogel (AG) encapsulating ferric tannate (TA-Fe) nanoparticles and vancomycin. The VAT hydrogel exhibited the outstanding photothermal properties and controllable antibiotics release. With the results of antibacterial assays, the VAT hydrogel revealed the superior effectiveness of synergistic wound disinfection by the low-intensity near-infrared light-triggered spatiotemporal antibiotics release and hyperthermia. More importantly, the VAT hydrogels possessed the good biocompatibility. With the outstanding synergistic sterilizing effect and excellent biocompatibility, the VAT hydrogel would be a promising candidate for bacteria-associated wound infections.

Boosting Chemodynamic Therapy by the Synergistic Effect of Co-Catalyze and Photothermal Effect Triggered by the Second Near-Infrared Light

In spite of the tumor microenvironments responsive cancer therapy based on Fenton reaction (i.e., chemodynamic therapy, CDT) has been attracted more attentions in recent years, the limited Fenton reaction efficiency is the important obstacle to further application in clinic. Herein, we synthesized novel FeO/MoS2 nanocomposites modified by bovine serum albumin (FeO/MoS2-BSA) with boosted Fenton reaction efficiency by the synergistic effect of co-catalyze and photothermal effect of MoS2 nanosheets triggered by the second near-infrared (NIR II) light. In the tumor microenvironments, the MoS2 nanosheets not only can accelerate the conversion of Fe3+ ions to Fe2+ ions by Mo4+ ions on their surface to improve Fenton reaction efficiency, but also endow FeO/MoS2-BSA with good photothermal performances for photothermal-enhanced CDT and photothermal therapy (PTT). Consequently, benefiting from the synergetic-enhanced CDT/PTT, the tumors are eradicated completely in vivo. This work provides innovative synergistic strategy for constructing nanocomposites for highly efficient CDT.

Application and prospect of antimonene: A new two-dimensional nanomaterial in cancer theranostics

With the rise of two-dimensional nanomaterials in medicine, finding suitable materials has become our top priority. Since the first report of antimonene in 2015, due to its excellent physical and chemical properties, it has gradually attracted widespread attention, including its application prospects in cancer treatment. In this paper, the preparation, stability and infrared degradability of antimonene, as well as its experimental examples in tumor treatment in recent years are reviewed, the latest research results are listed and summarized, the advantages and existing problems are analyzed, and the future of antimonene in tumor therapy is prospected.

Sensitive biosensor for p53 DNA sequence based on the photothermal effect of gold nanoparticles and the signal amplification of locked nucleic acid functionalized DNA walkers using a thermometer as readout

A convenient photothermal biosensor was constructed for p53 DNA sequence detection based on the high discrimination capability of locked nucleic acid and high efficiency of signal amplification strategy of DNA walkers and difference photothermal effect between aggregated and dispersed gold nanoparticles (AuNPs). The presence of target activated the DNA walkers via the high affinity between target and complementary locked nucleic acid in the probe strand, resulting in the hybridization of the walker strand and substrate strand to form a specific enzyme recognition site. Under the cleavage of the endonuclease, single-stranded DNA (ssDNA) was released to the solution. Then the walker strand bound to a new substrate strand, and the next round of cleavage was triggered. The released ssDNA enhanced the stability of AuNPs against salt-induced aggregation. Given difference photothermal effects of the aggregated AuNPs and dispersed AuNPs under the near-infrared laser, the change of the temperature was detected by a common thermometer easily, which had a linear relationship with the target concentration in the range of 2.0-120.0 pM, the detection limit was 1.4 pM (S/N = 3). The proposed photothermal assay has been applied to detect p53 DNA sequence spiked complex samples with satisfying results.

Laser-triggered collaborative chemophotothermal effect of gold nanoparticles for targeted colon cancer therapy

Nanotechnology has shown advantages for cancer treatment. Multimodal nanoparticles (NPs) combining chemotherapy and photothermal therapy are promising and elicit synergetic benefit. However, there were still less multifunctional nanomaterials with good targeting and anti-tumor property applied as the colon cancer therapeutic strategy. In this study, we designed the gold NPs modified with AS1411 and DNA riched of GC intercalation (hairpin DNA) with doxorubicin (DOX) for targeted chemotherapy and NIR laser-triggered chemo-photothermal effect (PTT). We took advantage of PTT effect to realize DOX release from hairpin DNA. We also demonstrated AS1411 based NPs exhibited remarkable targeted binding towards SW480 colon cancer cells in vitro and enhanced uptake inside the cells. Strikingly, AS1411 based NPs exhibited the most efficient cytotoxicity and markedly enhanced inhibition effect on cells proliferation to SW480 cells under laser exposure when compared to the NPs merely with PTT or chemotherapy. Our study appears to provide an alternative nanoplatform with good targeted and chemo-photothermal therapy against colon cancer.

Target-triggered aggregation of gold nanoparticles for photothermal quantitative detection of adenosine using a thermometer as readout

Colorimetric platform using the aggregation of gold nanoparticles (AuNPs) is a pretty simple method for biosensing, but advanced instruments such as specterophotometer is still needed to achieve accurately quantitative readout. Aggregated AuNPs exhibit excellent photothermal properties under near-infrared laser irradiation, which is significantly different from non-aggregated AuNPs. Herein, given the different photothermal effect, we translated the AuNPs-based colorimetric assay into a photothermal assay for the quantitative detection of adenosine using a thermometer as readout. Short single-stranded DNA (ssDNA, adenosine aptamer) was adsorbed on the surface of AuNPs and hence prevented the aggregation of AuNPs under high ionic concentration. The presence of adenosine caused the structural change of ssDNA and the AuNPs became aggregated. The enhanced temperature under NIR-laser irradiation has a linear response to the concentration of adenosine in the range of 2.0-50.0 μM. The detection limit was 1.7 μM. This proposed method is portable, easy and applicable to the quantitative assay of other targets by simply replacing of the sequence of ssDNA.

PB@PDA@Ag nanosystem for synergistically eradicating MRSA and accelerating diabetic wound healing assisted with laser irradiation

The ever-growing threats of multidrug-resistant bacterial infection and chronic wound healing have created an imperative need for the development of novel antibacterial materials and therapeutic strategies, especially for diabetic patients infected with multidrug-resistant bacteria. In this work, the nanocomplexes named as PB@PDA@Ag were used for eradicating multidrug-resistant bacteria and accelerating wound healing of MRSA-infected diabetic model with the assistance of laser irradiation. In vitro results revealed that the combinational strategy exerted a synergistic effect for anti-MRSA through disrupting cell integrity, producing ROS, declining ATP, and oxidizing GSH, comparing with PB@PDA@Ag or NIR laser irradiation alone. Moreover, in vivo assay demonstrated that this system effectively accelerated MRSA-infected diabetic wound healing by mitigating local inflammatory response and up-regulating VEGF expression on the wound bed. Meanwhile, satisfactory biocompatibility and negligible damage to major organs were observed. Altogether, the aforementioned results indicate that the combinational therapy of PB@PDA@Ag and NIR irradiation shows a great potential application in the field of clinic infection.

Development of a General Fabrication Strategy for Carbonaceous Noble Metal Nanocomposites with Photothermal Property

This study demonstrates a simple hydrothermal method while can be generalized for controllable synthesis of noble metallic carbonaceous nanostructures (e.g., Au@C, Ag@C) under mild conditions (180-200 °C), which also provides a unique approach for fabricating hollow carbonaceous structures by removal of cores (e.g., silver) via a redox etching process. The microstructure and composition of the as-achieved nanoparticles have been characterized using various microscopic and spectroscopic techniques. Cetyltrimethylammonium bromide (CTAB), serving as a surfactant in the reaction system, plays a key role in the formation of Ag@C, Au@C nanocables, and their corresponding hollow carbonaceous nanotubes in this work. The dynamic growth and formation mechanism of carbonaceous nanostructures was discussed in detail. And finally, laser-induced photothermal property of Au@C nanocomposites was examined. The results may be useful for designing and constructing carbonaceous metal(s) or metal oxide(s) nanostructures with potential applications in the areas of electrochemical catalysis, energy storage, adsorbents, and biomedicine. This study demonstrate a facile hydrothermal synthesis of noble metal carbonaceous nanocomposites (e.g., Au@C) with simple procedures under mild conditions, which can be25expanded as a general method for preparing diverse carbonaceous core-shell nanoparticles. The Au@C carbonaceous nanostructures exhibit interesting UV-Vis properties dependent upon shell thickness.

A bioinspired hyperthermic macrophage-based polypyrrole-polyethylenimine (Ppy-PEI) nanocomplex carrier to prevent and disrupt thrombotic fibrin clots

Fibrinolytic treatments for venous or arterial thrombotic syndromes using systemic administration of thrombolytics, such as streptokinase, can induce life-threatening bleeding complications. In this study, we offer the first proof of concept for a targeted photothermal fibrin clot prevention and reduction technology using macrophages loaded with polypyrrole-polyethylenimine nanocomplexes (Ppy-PEI NCs) and subjected to near-infrared radiation (NIR). We first show that the developed Ppy-PEI NCs could be taken up by defensive macrophages in vitro through endocytosis. The Ppy-PEI NCs generated local hyperthermia upon NIR treatment, which appeared to produce reactive oxygen species in Ppy-PEI NC-loaded macrophages. Preliminary evidence of efficacy as an antithrombotic tool is provided, in vitro, using fibrinogen-converted fibrin clots, and in vivo, in a rat femoral vascular thrombosis model generated by exposure to ferric chloride substance. The in vivo biocompatibility, photothermal behavior, biodistribution, and histological observation of cellular interactions with the Ppy-PEI NCs in the rat model provide rationale in support of further preclinical studies. This Ppy-PEI NC/NIR-based method, which uses a unique macrophage-guided targeting approach to prevent and lyse fibrin clots, may potentially overcome some of the disadvantages of current thrombolytic treatments. STATEMENT OF SIGNIFICANCE: Fibrinolytic treatments for venous or arterial thrombotic syndromes using systemic administration of thrombolytics, such as streptokinase, can induce life-threatening bleeding complications. In this study, we offer the first proof of concept for a targeted photothermal fibrin clot reduction technology using macrophages loaded with polypyrrole-polyethylenimine nanocomplexes (Ppy-PEI NCs) and subjected to near-infrared radiation (NIR). We first show that the developed Ppy-PEI NCs can be taken up by defensive macrophages in vitro through endocytosis. The Ppy-PEI NCs generated local hyperthermia upon NIR treatment, which appeared to produce reactive oxygen species in Ppy-PEI NC-loaded macrophages. Preliminary evidence of efficacy as an antithrombotic tool is provided, in vitro, using fibrinogen-converted fibrin clots, and in vivo, in a rat femoral vascular thrombosis model generated by exposure to ferric chloride substance. The in vivo biocompatibility, photothermal behavior, biodistribution, and histological observation of cellular interactions with the Ppy-PEI NCs in the rat model provide rationale in support of further preclinical studies. This Ppy-PEI NC/NIR-based method, which uses a unique macrophage-guided targeting approach to disintegrate fibrin clots, may potentially overcome some of the disadvantages of current thrombolytic treatments.

Ag2S nanocrystallites deposited over polyamidoamine grafted carbon nanotubes: An efficient NIR active photothermal agent

A novel NIR (near infrared) active photothermal agent, CNTs-PAMAM-Ag₂S has been synthesized by covalent grafting of polyamidoamine (PAMAM) to carbon nanotubes (CNTs) and subsequent deposition of Ag₂S nanocrystallites. The potential of CNTs-PAMAM-Ag₂S as a NIR active photothermal agent was preliminarily accessed by its electronic absorption spectrum measured in UV-vis-NIR region. The CNTs-PAMAM-Ag₂S exhibited excellent photothermal effect and photothermal conversion efficiency of 26% under illumination with 980 nm laser, the efficiency was found to be higher than popular gold and copper based photothermal agents. Temperature attained by CNTs-PAMAM-Ag₂S during measurement of its photothermal effect was 64.7 °C at 1 g/mL, which far exceeds the temperature tolerance level of cancer cells. So that CNTs-PAMAM-Ag₂S could destroy the cancer cells in an effective manner. Furthermore, it was found the linear dependence of photothermal effect of CNTs-PAMAM-Ag₂S over its concentration. CNTs-PAMAM-Ag₂S possessed excellent stability against photo-bleaching and photo-corrosiveness. In consideration of its outstanding photothermal effect and photothermal conversion efficiency, CNTs-PAMAM-Ag₂S could be a promising photothermal agent to employ in future photothermal therapy.

Engineered nanomedicine for neuroregeneration: light emitting diode-mediated superparamagnetic iron oxide-gold core-shell nanoparticles functionalized by nerve growth factor

This paper reports nerve growth factor functionalized superparamagnetic iron oxide-gold core-shell nanoparticles (NGF-SPIO-Au NPs), an engineered nanomedicine for non-invasive neuron regeneration when irradiated by a low-intensity light-emitting diode (LED). NGF-SPIO-Au NPs of 20 μg/ml, were tested on PC-12 neuron-like cells, irradiated by LEDs (525 nm, 1.09, 1.44, and 1.90 mW/cm²). A remarkable Ca²⁺ influx was detected in differentiated PC-12 cells treated with NPs, irradiated by LED of 1.90 and 1.44 mW/cm² with great cell viability (>84%) and proliferations. The strong heat generated through their plasmonic surface upon LED irradiation on NGF-SPIO-Au NPs was observed. For cells treated with LED (1.90 mW/cm²) and NGF-SPIO-Au NPs, a dramatic enhancement of neuronal differentiation (83%) and neurite outgrowth (51%) was found, and the upregulation of both the neural differentiation specific marker (β3-tubulin) and the cell adhesive molecule (integrin β1) was observed by the reverse transcription-polymerase chain reaction and western blot analysis.

A novel macrophage-mediated biomimetic delivery system with NIR-triggered release for prostate cancer therapy

Background

Macrophages with tumor-tropic migratory properties can serve as a cellular carrier to enhance the efficacy of anti neoplastic agents. However, limited drug loading (DL) and insufficient drug release at the tumor site remain the main obstacles in developing macrophage-based delivery systems. In this study, we constructed a biomimetic delivery system (BDS) by loading doxorubicin (DOX)-loaded reduced graphene oxide (rGO) into a mouse macrophage-like cell line (RAW264.7), hoping that the newly constructed BDS could perfectly combine the tumor-tropic ability of macrophages and the photothermal property of rGO.

Results

At the same DOX concentration, the macrophages could absorb more DOX/PEG-BPEI-rGO than free DOX. The tumor-tropic capacity of RAW264.7 cells towards RM-1 mouse prostate cancer cells did not undergo significant change after drug loading in vitro and in vivo. PEG-BPEI-rGO encapsulated in the macrophages could effectively convert the absorbed near-infrared light into heat energy, causing rapid release of DOX. The BDS showed excellent anti-tumor efficacy in vivo.

Conclusions

The BDS that we developed in this study had the following characteristic features: active targeting of tumor cells, stimuli-release triggered by near-infrared laser (NIR), and effective combination of chemotherapy and photothermotherapy. Using the photothermal effect produced by PEG-BPEI-rGO and DOX released from the macrophages upon NIR irradiation, MAs-DOX/PEG-BPEI-rGO exhibited a significant inhibitory effect on tumor growth.

Photothermal Effect of Modulating Laser Irradiation on the Thermal Diffusivity of Al2O3 Nanofluids

Modulated continuous wave (CW) lasers cause photothermal effect that leads to rapid optical absorption and generation of thermal waves around the irradiated nanostructures. In this work, we examined the effect of modulated CW laser irradiation on the particle fragmentation process to enhance the thermal diffusivity of nanofluids. A facile and cost-effective diode laser was applied to reduce the agglomerated size of Al₂O₃ nanoparticles in deionized water. The thermal wave generation, which was determined by the modulated frequency of the laser beam and the optical and thermal properties of the nanofluid, is also briefly discussed and summarized. The influence of laser irradiation time on nanoparticle sizes and their size distribution was determined by dynamic light scattering and transmission electron microscopy. The thermal diffusivity of the nanofluid was measured using the photopyroelectric method. The data obtained showed that the modulated laser irradiation caused the partial fragmentation of some agglomerated particles in the colloids, with an average diameter close to the original particle size, as indicated by a narrow distribution size. The reduction in the agglomerated size of the particles also resulted in an enhancement of the thermal diffusivity values, from 1.444 × 10^-3 to 1.498 × 10^-3 cm²/s in 0 to 30 min of irradiation time. This work brings new possibilities and insight into the fragmentation of agglomerated nanomaterials based on the photothermal study.

Utilisation of antimicrobial photodynamic therapy as an adjunctive tool for open flap debridement in the management of chronic periodontitis: A randomized controlled clinical trial

BACKGROUND

Antimicrobial photodynamic therapy (aPDT) has proved to be an effective adjunctive modality with potential benefits in the management of chronic periodontitis. The combination of photothermal and photodynamic effects of Indocyanine green (ICG) dye, when it is photoactivated with a diode laser of 810 nm wavelength, has been well documented in literature.

AIM

This study was conducted to evaluate whether a single session of antimicrobial photodynamic therapy using ICG dye-810 nm diode laser combination can provide a substantial benefit when it is utilised as an adjunct to open flap debridement (OFD) in the management of chronic periodontitis.

MATERIALS AND METHOD

Following thorough scaling and root planing, a comparative split mouth randomized controlled clinical trial was carried out on 20 recruited subjects who provided one test (OFD + aPDT) and one control site (OFD alone) each (total 40 treatment sites). The test group was subjected to a single episode of aPDT using ICG photosensitiser dye (1 mg/ml) activated with 810 nm diode laser. The laser was used in a continuous wave, non-contact mode at a power output of 100 mW applied for 30 s/spot (the total of 4 spots per tooth) and delivered by 400 μm fibre, to provide a fluence (energy density) value of 0.0125 J/cm² per spot and generate a total energy of 3 J. The following clinical parameters were assessed at baseline and 3 months: probing pocket depth (PPD), relative attachment level (RAL), relative gingival margin level (RGML), plaque index (PI), gingival index (GI), and gingival bleeding index (GBI). Intragroup and intergroup comparison was performed using paired t-test and independent samples t-test respectively.

RESULTS

Intragroup comparison revealed a statistically significant improvement from baseline visit (p < 0.05). Intergroup comparison showed a statistically significant improvement in RAL, RGML and GI in the test group (p < 0.05).

CONCLUSION

Utilisation of ICG dye activated with 810 nm diode laser, which mediated aPDT, has demonstrated surplus clinical improvement following OFD in the management of chronic periodontitis.

Photothermal effect of Ag nanoparticles deposited over poly(amidoamine) grafted carbon nanotubes

This paper illustrates the potential of Ag nanoparticles based nanocomposites to use as effective agents in photothermal therapy apart from their traditional employment as antimicrobial materials. Herein an Near- Infrared active photothermal agent was fabricated by deposition of Ag nanoparticles over aromatic poly(amidoamine) grafted carbon nanotubes. Thus prepared CNTs-PAMAM-Ag possessed strong photothermal effect under exposure to 980 nm laser system and prominent photothermal stability. The photothermal conversion efficiency of CNTs-PAMAM-Ag was found to be higher than readily used Au and CuS based photothermal agents. The photothermal effect of CNTs-PAMAM-Ag was substantial in presence of 980 nm laser compared to 808 nm laser and a linear dependence of photothermal effect on its concentration was identified. The maximum temperature attained by CNTs-PAMAM-Ag during assessment of its photothermal effect was about 66.0 °C, which is significantly higher than the survival temperature level of cancer cells. So CNTs-PAMAM-Ag could be a promising photothermal agent to apply in future photothermal hyperthermia therapy to treat cancer. Moreover CNTs-PAMAM-Ag can synchronous trigger by a single wavelength (980 nm) laser system, so it could simplify the future therapeutic process.

Hyaluronic acid functionalized green reduced graphene oxide for targeted cancer photothermal therapy

Reduced graphene oxide (rGO) nanomaterials display promising properties for application in cancer photothermal therapy (PTT). rGO is usually obtained by treating graphene oxide (GO) with hydrazine hydrate. However, this reducing agent contributes for the low cytocompatibility exhibited by rGO. Furthermore, rGO has a low water stability and does not show selectivity towards cancer cells. Herein, rGO attained using an environmentally-friendly method was functionalized with a novel hyaluronic acid (HA)-based amphiphilic polymer to be used in targeted cancer PTT. Initially, the green-reduction of GO with L-Ascorbic acid was optimized considering the near infrared absorption and the size distribution of the nanomaterials. Then, rGO was functionalized with the HA-based amphiphile. The functionalization of rGO improved its stability, cytocompatibility and internalization by CD44 overexpressing cells, which indicates the targeting capacity of this nanoformulation. Furthermore, the on-demand PTT mediated by HA-functionalized rGO induced cancer cells' ablation, thereby confirming its potential for targeted cancer therapy.

Exploring the influence of Diels-Alder linker length on photothermal molecule release from gold nanorods

We studied the photothermal release of carboxyfluorescein (CF) linked to the gold surface of gold nanorods (GNRs) by two Diels-Alder adducts of different lengths (n = 4 and n = 9). The functionalized GNRs were irradiated with infrared light to produce photothermal release of CF by a retro-Diels-Alder reaction. The adducts were chemisorbed on the GNRs and the functionalized nanoparticles were characterized by UV-vis, DLS, zeta potential and Raman and surface-enhanced Raman spectroscopy (SERS). On the basis of the degree of nanoparticle functionalization and the SERS results, we inferred the orientation of CF on the surface of the gold nanoparticle. Moreover, we determined the photothermal release profiles of CF from the gold surface by laser irradiation. The release was faster for the longer linker (n = 9). SERS revealed that, for the shorter linker (n = 4), molecules are oriented perpendicularly with respect to the gold surface, thereby maintaining the CF far from the surface. In contrast, the longer linker was observed to be tilted, thus maintaining CF close to the gold surface and therefore potentially favoring the photothermal transfer of energy. These results are relevant for the future development of the spatial and temporal controlled release of drugs by means of gold nanoparticles.

In-situ NIR-laser mediated bioactive substance delivery to single cell for EGFP expression based on biocompatible microchamber-arrays

Controlled drug delivery and gene expression is required for a large variety of applications including cancer therapy, wound healing, cell migration, cell modification, cell-analysis, reproductive and regenerative medicine. Controlled delivery of precise amounts of drugs to a single cell is especially interesting for cell and tissue engineering as well as therapeutics and has until now required the application of micro-pipettes, precisely placed dispersed drug delivery vehicles, or injections close to or into the cell. Here we present surface bound micro-chamber arrays able to store small hydrophilic molecules for prolonged times in subaqueous conditions supporting spatiotemporal near infrared laser mediated release. The micro-chambers (MCs) are composed of biocompatible and biodegradable polylactic acid (PLA). Biocompatible gold nanoparticles are employed as light harvesting agents to facilitate photothermal MC opening. The degree of photothermal heating is determined by numerical simulations utilizing optical properties of the MC, and confirmed by Brownian motion measurements of laser-irradiated micro-particles exhibiting similar optical properties like the MCs. The amount of bioactive small molecular cargo (doxycycline) from local release is determined by fluorescence spectroscopy and gene expression in isolated C2C12 cells via enhanced green fluorescent protein (EGFP) biosynthesis.

Photothermal Determination of Absorption and Scattering Spectra of Silver Nanoparticles

This work reports on photothermal lens spectra of silver nanoparticles of different dimensions in the spectral region of 370-730 nm performed using an arc-lamp-based photothermal spectrophotometer. We show that the photothermal and extinction cross-section spectra of the samples are similar for nanoparticles of reduced dimensions where scattering effects are small. The results differ substantially for nanoparticles of a diameter larger than 30 nm for which scattering becomes relevant. We demonstrate that the photothermal spectrum corresponds to the absorption component of the particle's extinction. Photothermal spectra show a clear picture of the plasmonic peaks of the nanoparticle even in the presence of high scattering. By subtracting the photothermal component from the total extinction, we extract the scattering cross-section spectra of the nanoparticles. The technique allows determination of the absorption and scattering components of the extinction providing a better understanding of the particle's optical properties. The results agree well with the Mie approximation, which is valid for a single spherical nanoparticle. We discuss and demonstrate the application of the method to characterize particles of arbitrary shape and dimensions.

A drug release system induced by near infrared laser using alginate microparticles containing melanin

The photothermal effect is used in a new drug release system to control drug delivery in a specific region. Melanin absorbs near-infrared (NIR) light with a high photothermal conversion efficiency, and as a result, an NIR laser can be used to induced drug release from alginate microparticles containing melanin (ALG-Mel microparticles). The temperature of the ALG-Mel microparticle solution at a concentration of 5mg/mL increased to 38.1°C from 26.0°C after irradiation with 808nm NIR at 1.5W/cm² for 5min, and this increase in temperature was found to be independent of the ALG-Mel microparticle concentration. After the NIR laser irradiation, 5-fluorouracil (5-FU) was released from the ALG-Mel microparticles to 87.4±0.5% of the total loaded drug for 24h. Without NIR laser irradiation, 5-FU was released from the ALG-Mel microparticles to 60.8±1.5% of the total loaded drug for 24h. These results indicate that NIR laser irradiation can be used with ALG-Mel microparticles as a drug delivery system for release within a target region.

Single wavelength light-mediated, synergistic bimodal cancer photoablation and amplified photothermal performance by graphene/gold nanostar/photosensitizer theranostics

Light-triggered nanotheranostics opens a fascinating but challenging avenue to achieve simultaneous and highly efficient anticancer outcomes for multimodal therapeutic and diagnostic modalities. Herein, a multifunctional phototheranostics based on a photosensitizer-assembled graphene/gold nanostar hybrid (GO/AuNS-PEG) was developed for cancer synergistic photodynamic (PDT) and photothermal therapy (PTT) as well as effective photothermal imaging. The stable and biocompatible GO/AuNS-PEG composite displayed a high photothermal conversion efficiency due to the enhanced optical absorbance of both graphene and gold nanostars in the near-infrared (NIR) range. By tuning the absorption wavelength of GO/AuNS-PEG to that of Chlorin e6 (Ce6), GO/AuNS-PEG/Ce6 completely eliminated the EMT6 xenograft tumors by the tremendous synergistic anticancer efficiency of simultaneous PDT and PTT under a single NIR laser irradiation (660nm) in vivo. The underlying mechanism may be the enhanced cytoplasmic uptake and accumulation of GO/AuNS-PEG/Ce6 and the subsequent photodestruction of the lysosomal membrane and mitochondria. Moreover, GO/AuNS-PEG/Ce6 exhibited negligible side-effects on the body and other organs. These results demonstrate that the graphene/gold nanostar nanoconstruct provides a versatile and reliable integrated platform for the photo-controlled cancer theragnostic applications.

STATEMENT OF SIGNIFICANCE

This work demonstrated the application of graphene-Au Nanostars hybridized system (denoted as GO/AuNS-PEG) in single wavelength laser induced synergistic photodynamic (PDT) and photothermal therapy (PTT) and effective cancer photothermal/fluorescence multimode imaging. GO/AuNS-PEG showed excellent biocompatibility and high dual-enhanced photothermal efficiency under the near-infrared laser irradiation that was very promise for deep tumor imaging. By combining with the photosensitizer Chlorin e6, both in vitro and in vivo data confirmed the efficient photoablation of the EMT6 tumors through the synergistic PDT and PTT effect under the activation of a single wavelength laser.