Photothermal Activity Research Articles

A Self‐Reporting Mineralized Conductive Hydrogel Sensor with Cancer‐Selective Viscosity, Adhesiveness, and Stretchability

AbstractA cancer‐selective self‐reporting sensor based on a redox‐responsive mineralized conductive hydrogel (M‐Hydrogel) is proposed with cancer‐specific viscosity, adhesive strength, stretchability, tunable conductivity, and fluorescence. The redox‐triggered release of carbonized polydopamine (cPDA) from the loaded disulfide‐crosslinked polymer dots (PD@cPDA) in the hydrogel matrix modulates the macroporous structure responsible for self‐recognizable cancer sensing and photothermal activity for cancer therapy. The self‐reporting nature of the M‐Hydrogel sensor is highlighted when in vicinity of a high glutathione (GSH) level owing to the controllable pore size and H‐bonding by cPDA, as confirmed by experiments on cancer cells (HeLa, PC3, B16‐F10‐GFP, and SNU‐C2A) and normal cells (CHO‐K1). The lower viscosity during syringe test along with the exceptional adhesiveness and stretchability with various cancer cells, combined with a high wireless pressure‐sensing response absent in normal conditions, confirms the dependence of self‐recognizable behavior on the cancer microenvironment. The M‐Hydrogel demonstrates excellent ex situ sensing with tumor ablation, after implantation in mice xenografted with HeLa cells, with the wireless sensing system, enabling real‐time analysis coupled with the upregulation of pro‐apoptotic markers P53 and BAX in the tumor. Therefore, this self‐reporting sensor may facilitate a strategy for innovative and convenient cancer diagnostics.

Multifunctional chitosan/alginate hydrogel incorporated with bioactive glass nanocomposites enabling photothermal and nitric oxide release activities for bacteria-infected wound healing

It is highly desirable to develop novel multifunctional wound dressing materials capable of delivering active molecules capable of resolving bacterial infections and replenishment of appropriate growth factors for bacteria-infected wound healing. Polysaccharides have numerous biomedical benefits and have been widely used to construct biomaterial scaffolds. Herein, multifunctional chitosan/alginate hydrogel decorated with β-cyclodextrin (β-CD) modified polydopamine (PDA)-bioactive glass (BG) nanoparticles (NPs) integrating photothermal performance and nitric-oxide release activities for the treatment of bacterially infected wounds is presented. As the NO precursor N,N′-di-sec-butyl-N,N′-dinitroso-1,4-phenylenediamine (BNN6) encapsulated into the hydrophobic cavity of β-CD on the PDA-coated BG NPs, the resultant NO@CD-PDA/BG NPs, are imparted with the feature of NIR triggered NO release and desired PTT/NO synergetic antibacterial effects. Furthermore, the release of NO, Ca, and Si ions from the NO@CD-PDA/BG NPs, has the benefit of regulating inflammation, promoting fibroblast proliferation, and stimulating angiogenesis. Besides, the chitosan/alginate hydrogel scaffolds provided a suitable microenvironment to accelerate wound healing. By applying the multifunctional chitosan/alginate nanocomposite hydrogel to S. aureus-infected full-thickness skin defect mouse model, the authors demonstrated that chitosan/alginate nanocomposite hydrogel has multiple functions in preventing bacterial infections, accelerating angiogenesis and wound regeneration, indicating promising application in wound healing.

Precise Photothermal Treatment of Methicillin-Resistant S. aureus Infection via Phage Lysin-Cell Binding Domain-Modified Gold Nanosheets.

The increasing spread of antibiotic resistance in bacterial pathogens poses a huge threat to global human health. Precise targeting of bacterial pathogens while avoiding collateral damage to healthy tissues has become the overriding goal for bacterial infection treatment. Inspired by the host specificity of bacteriophages, a biomimetic intelligent platform was designed for highly precise photothermal treatment herein. As proof-of-concept, the lysin cell-binding domain (CBD) from a newly discovered virulent methicillin-resistant S. aureus (MRSA) phage Z was applied to the functionalization of gold nanosheets. Our results demonstrated that the bionanocomposite gold particles (Au@PEG-CBDz) could be effectively delivered directly to MRSA and kill them effectively under near infrared irradiation in vitro, while displaying good in vivo biocompatibility. This work is the first to report the combination of phage lysin navigatory function with photothermal effect-induced bactericidal activity from Au nanosheets, providing a novel therapeutic mode for the precision treatment of antibiotic-resistant bacterial infections.

MXene-intercalated montmorillonite nanocomposites for long-acting antibacterial

MXene has attracted widespread attention in the field of antibacterial due to the unique photothermal and photodynamic property. However, its application in durable antimicrobial field is greatly limited by its instability and weak antibacterial activity. In this study, ultrasonic-impelled MXene was used to intercalate montmorillonite (MMT) layers and fabricate montmorillonite/MXene nanocomposites (MTX) with micro-nano protective structure. The nanoconfinement effect protected MXene from oxidation for 30 days, making it possible to long-term use. Furthermore, hydrophilic Ag NPs synthesized by natural polymer lignin were immobilized in the MTX, which could enhance the antibacterial effect of MTX and retard the cumulative release of Ag NPs. MTX/Ag exhibited excellent photothermal, photodynamic and antibacterial activity, achieving over 99.9 % antibacterial efficacy against S. aureus for 28 days. Meanwhile, the antibacterial mechanism of MTX/Ag has been thoroughly studied. Importantly, the stability of MTX endowed the MTX/Ag-NIR with photothermal stability and cyclic stability, achieving 30 days antifungal effect on wood powder. These studies provided a novel idea to fabricate a stable, long-acting, and efficient antibacterial agent for precious furniture.

Synthesis and photothermal/photodynamic antimicrobial activities of phthalocyanines tetra-substituted by morpholinyl moieties

A series of ɑ-tetra-substituted phthalocyanines (M = 2H, Cu, Co, Ni) with morpholinyl moieties and their corresponding quaternized derivatives have been synthesized. The spectroscopic and photosensitizing properties, photothermal effects, aggregation trend, and partition coefficients of these phthalocyanines are evaluated. Besides, we appraised their photothermal and photodynamic activities against C. albicans and E. coli under near-infrared (NIR) light irradiation (680 nm). The results show that cationic phthalocyanines are more efficacies in killing bacteria and fungi than their neutral analogues. For copper (II) phthalocyanine 4b and metal-free phthalocyanine 7b, their photodynamic activities play a key role in antimicrobial treatment, while for other phthalocyanines, their photothermal effects play a major role. Moreover, metal-free phthalocyanine 7b exhibits an ideal synergistic photothermal/photodynamic antimicrobial activity and shows the highest photocytotoxicity among all the compounds. The IC90 values of 7b towards C. albicans and E. coli are as low as 1.12 μM and 0.47 μM, respectively, while others have IC90 values ranging from 3.31 μM to 50 μM, implying that 7b would be a good candidate for future antimicrobial applications.

Solution-Processable PEDOT Particles for Coatings of Untreated 3D-Printed Thermoplastics

Lack of solution processability is the main bottleneck in research progression and commercialization of conducting polymers. The current strategy of employing a water-soluble dopant (such as PEDOT:PSS) is not feasible with organic solvents, thus limiting compatibility on hydrophobic surfaces, such as three-dimensional (3D) printable thermoplastics. In this article, we utilize a colloidal dispersion of PEDOT particles to overcome this limitation and formulate an organic paint demonstrating conformal coating on 3D-printed objects. We start with synthesizing PEDOT particles that possess a low electrical resistance (gap resistance of 4.2 ± 0.5 Ω/mm). A particle-based organic paint is formulated and applied via brush painting. Coated objects show a surface resistance of 1 kΩ/cm, comparable to an object printed by commercial conductive filaments. The coating enables the fabrication of pH and strain sensors. Highly conductive PEDOT particles also absorb light strongly, especially in the near-infrared (NIR) range due to the high concentration of charge carriers on the polymer's conjugated backbones (i.e., polarons and bipolarons). PEDOT converts light to heat efficiently, resulting in a superior photothermal activity that is demonstrated by the flash ignition of a particle-impregnated cotton ball. Consequently, painted 3D prints are highly effective in converting NIR light to heat, and a 5 s exposure to a NIR laser (808 nm, 0.8 mW/cm2) leads to a record high-temperature increase (194.5 °C) among PEDOT-based coatings.

Facile synthesis of single-crystalline MnO2 nanowire arrays with high photothermal catalytic activity.

A simple process has been developed to form single-crystalline β-MnO2 nanowire arrays (NWAs) with a large surface area of 125 m2 g-1 on a glass plate working as a highly active three dimensional (3D) photothermal catalyst under the illumination of near infrared light due to the efficient light harvesting and heat confinement near the reaction field in addition to the large surface area.

Quercetin@Gd3+ doped Prussian blue nanocubes induce the pyroptotic death of MDA-MB-231 cells: combinational targeted multimodal therapy, dual modal MRI, intuitive modelling of r1-r2 relaxivities.

Quercetin (Qu), a potential bioflavonoid has gained considerable interest as a promising chemotherapeutic drug which can inhibit the proliferation of triple-negative breast cancer (TNBC) cells due to its regulation of the expression of tumor-suppressor gene metastasis and antioxidant property. Notably, Qu exhibits a very negligible cytotoxic effect on normal cells, even with high-dose treatment, while it is shows high affinity to TNBC. However, the efficiency of Qu is limited clinically due to its poor bioavailability, caused by its low aqueous solubility (2.15 μg mL-1 at 25 °C), rapid gastrointestinal digestion and chemical instability in alkaline and neutral media. Herein, polydopamine (PDA)-coated, NH2-PEG-NH2 and hyaluronic acid (HA)-functionalized Gd3+-doped Prussian blue nanocubes (GPBNC) are reported as a multifunctional platform for the codelivery of Qu as a chemotherapeutic agent and GPBNC as a photodynamic (PDT) and photothermal (PTT) agent with improved therapeutic efficiency to overcome theses barriers. PDA, NH2-PEG-NH2 and HA stabilize GPBNC@Qu and facilitate bioavailability and active-targeting, while absorption of near infrared (NIR) (808 nm; 1 W cm-2) induces PDT and PTT activities and dual T1-T2-weighted magnetic resonance imaging (MRI) with high relaxometric parameters (r1 10.06 mM-1 s-1 and r2 24.96 mM-1 s-1 at a magnetic field of 3 T). The designed platform shows a pH-responsive Qu release profile and NIR-induced therapeutic efficiency of ∼79% in 20 minutes of irradiation, wherein N-terminal gardermin D (N-GSDMD) and a P2X7-receptor-mediated pyroptosis pathway induces cell death, corroborating the up-regulation of NLRP3, caspase-1, caspase-5, N-GSDMD, IL-1β, cleaved Pannexin-1 and P2X7 proteins. More interestingly, the increasing relaxivity values of Prussian blue nanocubes with Gd3+ doping have been explained on the basis of Solomon-Bloembergen-Morgan theory, considering inner- and outer-sphere relaxivity, wherein crystal defects, coordinated water molecules, tumbling rate, metal to water proton distance, correlation time, magnetisation value etc. play a significant role. In summary, our study suggests that GPBNC could be a beneficial nanocarrier for theranostic purposes against TNBC, while our conceptual study clearly demonstrates the role of various factors in increasing relaxometric parameters.

Cu-BTC-confined synthesis of Cu-Cu2O-CuS nanojunctions embedded in a porous carbon matrix for remarkable photothermal CO2conversion

Cu-Cu2O-CuS nanojunctions confined within a porous carbon octahedron matrix are fabricated and exhibit excellent photothermal catalytic activity toward CO2conversion.

Capping and etching roles of copper ions in controlled synthesis of Au-PtCu trimetallic nanorods with improved photothermal and photocatalytic activities.

Heterocrystals consisting of multiple species have received wide attention owing to the advantage of the cooperative effect contributed by different functional counterparts; therefore, a controlled growth strategy is highly desired. Herein, we report an effective method to synthesize dumbbell-like Au-PtCu solid and hollow nanorods, regulated by the unique surface capping and oxidation etching roles of copper ions. Dumbbell-like nanorods are prepared through site-selective co-deposition of platinum and copper on both tips of gold nanorods assisted by the capping effect of the CTAB-Cu+ complex to passivate the side surface. On the other hand, hollow dumbbell-like Au-PtCu nanorods are formed through triggering the etching effect of copper ions by increasing the reaction temperature to 80 °C. The manipulation of the morphology and extinction properties of the trimetallic Au-PtCu nanorods is demonstrated by adjusting the concentration of copper ions. Under excitation with a near-infrared 808 nm laser, the dumbbell-like Au-PtCu nanorods show excellent photothermal conversion, with a 3.1 times temperature increment (ΔT) compared to bare Au nanorods, while the hollow dumbbell-like Au-PtCu NRs demonstrate improved photocatalytic activity under xenon lamp irradiation.

Promoting photothermal antibacterial activity through an excited-state intramolecular proton transfer process.

The construction of an efficient photothermal antibacterial platform is a promising strategy for the treatment of drug-resistant bacterial infections. Herein, through the introduction of excited-state intramolecular proton transfer to promote the photothermal effect, N-(2,4-dihydroxybenzylidene)-4-aminophenol (DOA)-polyvinyl alcohol (PVA) systems (DPVA) can reach 55 °C within 10 s under irradiation. They show superior antibacterial behavior against drug-resistant bacteria and a therapeutic effect on infected skin wounds with only 100 s of irradiation, much faster than those of reported photothermal materials (5-10 min). This work provides a convenient approach to fabricate broad-spectrum antibacterial wound dressings for treating bacteria-infected wounds, greatly contributing to the design and applications of photothermal antibacterial platforms.

Plasmonic Ag@Cu2O core-shell nanostructures exhibiting near-infrared photothermal effect.

This work was devoted to the investigation of the optical properties, structural characterization, and photothermal conversion performance of Ag@Cu2O nanostructures. The selection of anisotropic silver core, specifically Ag nanocubes, was driven by the possibility to tune LSPR across a broader range of the electromagnetic spectrum. The thickness of the Cu2O shell was intentionally changed through the variation in the Cu salt to the metal core nanoparticles ratios. The LSPRs of Ag(nanocube)@Cu2O core-shell nanoparticles can be fine-tuned to the spectral region to become resonant with the excitation wavelengths of 808 nm NIR laser. Due to the high refractive index of the deposited Cu2O, the redshifts of the plasmon band wavelength in the extinction spectra were observed. Consequently, the photothermal activities of the Ag(nanocube)@Cu2O core-shell NPs have been controlled by the shell thickness at the nanoscale. Ag@Cu2O nanoparticles with thickest shell (∼70 nm) exhibit the most efficient NIR photothermal effect under the irradiation of 808 nm laser at ambient conditions. Results of this work demonstrate that Ag@Cu2O hetero-nanostructures may be optimized and used for the efficient transformation of light into other forms of energy, specifically heat.

Au nanoparticles decorated nanographene oxide-based platform: Synthesis, functionalization and assessment of photothermal activity

A novel hybrid nanocomposite formed of carboxylated Nano Graphene Oxide (c-NGO), highly densely decorated by monodisperse citrate-coated Au nanoparticles (c-NGO/Au NPs), is synthesized and thoroughly characterized for photothermal applications. A systematic investigation of the role played by the synthetic parameters on the Au NPs decoration of the c-NGO platform is performed, comprehensively studying spectroscopic and morphological characteristics of the achieved nanostructures, thus elucidating their still not univocally explained synthesis mechanism.Remarkably, the Au NPs coating density of the c-NGO sheets is much higher than state-of-the-art systems with analogous composition prepared with different approaches, along with a higher NPs size dispersion. A novel theoretical approach for estimating the average number of NPs per sheet, combining DLS and TEM results, is developed. The assessment of the c-NGO/Au NPs photothermal activity is performed under continuous wave (CW) laser irradiation, at 532 nm and 800 nm, before and after functionalization with PEG-SH. c-NGO/Au NPs composite behaves as efficient photothermal agent, with a light into heat conversion ability higher than that of the single components. The c-NGO/Au NPs compatibility for photothermal therapy is assessed by in vitro cell viability tests, which show no significant effects of c-NGO/Au NPs, as neat and PEGylated, on cell metabolic activity under the investigated conditions. These results demonstrate the great potential held by the prepared hybrid nanocomposite for photothermal conversion technologies, indicating it as particularly promising platform for photothermal ablation of cancer cells.

Antibody conjugated Au/Ir@Cu/Zn-MOF probe for bacterial lateral flow immunoassay and precise synergistic antibacterial treatment

Staphylococcus aureus is one of the most prevalent threats to public health. Rapid detection with high sensitivity and targeted killing is crucial to curb its spread. Herein, a metal-bearing nanocomposite, consisting of a bimetallic nanoparticle and a metal-organic framework (Au/Ir@Cu/Zn-MOF) was constructed. Upon conjugation with anti-S. aureus antibody, this nanocomposite (Ab-Au/Ir@Cu/Zn-MOF) was exploited for its dual functions, i.e. as a reporting probe in a lateral flow immunoassay and a high efficiency antibacterial reagent. Benefiting from the enrichment of Au/Ir NPs by the Cu/Zn-MOF, the Au/Ir@Cu/Zn-MOF-based lateral flow immunoassay sensor exhibited a visual limit of detection of 103 CFU/mL, which was100 times more sensitive than Au/Ir-based sensor. Moreover, the Ab-Au/Ir@Cu/Zn-MOF probe possessed synergistic photothermal-chemodynamic bactericidal effect that specifically targeted against S. aureus. Under a co-treatment by H2O2 (0.4 mM) and 808 nm near infrared irradiation (1 W/cm2, 5 min), complete sterilization of 5 × 105–106 CFU/mL S. aureus was achieved at a nanocomposite concentration as low as 6.25 μg/mL. The superior antibacterial efficiency was attributable to the three-fold properties of the Ab-Au/Ir@Cu/Zn-MOF probe: (1) enhanced multi-enzyme mimicking activities that promote reactive oxygen species generation, (2) high photothermal activity (efficiency of 53.70%), and (3) bacteria targeting ability via the antibody coating. By changing the antibody, this nanocomposite can be tailored to target a wide range of bacteria species, for detection and for precise antibacterial treatment.

Constructing MOFs-derived Co3O4 microsphere with atomic p-n homojunction as an efficient photothermal catalyst for boosting ethyl acetate oxidation under light irradiation

A synthetic strategy for Co-MOF-74-derived Co3O4-based materials (polyhedral prism, hexagonal-prism spindle and prism-assembly 3D microspheres with different surface dense degrees) with atomic p-n homojunctions were proposed by introducing a dual-ligand (2,5-dihydroxyterephthalic acid and 2-methylimidazole) approach in the hydrothermal process. Among these Co3O4-based catalysts, the Co3O4-M-3 catalyst with 3D prism-assembly microsphere exhibited the greatest photothermal catalytic activity for ethyl acetate oxidation (around 92%) under the visible-IR light intensity of 480 mW/cm2 (λ > 420nm). The smart modulation of dual-ligand approach could effectively improve the oxygen storage capacity, abundant oxygen vacancies and outstanding reductive ability over the Co3O4-M-3 catalyst. In addition, Mott-Schottky plot characterization verified the formation of p-n homojunction over the Co3O4-M-3, and its suitable energy band level and Z-scheme charge transfer pathway effectively improved visible-light absorption capacity, accelerated charge pairs transportation and restrained photogenerated electron-hole recombination. Finally, in situ DRIFTS results demonstrated that the adsorbed oxygen and lattice oxygen would participate in the photothermal catalytic reaction. Ethanol and acetic acid were considered as a main reaction pathway, whereas methyl ethyl ketone as no-critical intermediate was generated in the strict condition with exclusive active lattice oxygen of catalyst and light irradiation.

Natural halloysite nanotubes supported Ru as highly active catalyst for photothermal catalytic CO2 reduction

Photothermal catalytic CO2 reduction has emerged as a promising approach to efficiently utilize solar energy and reduce greenhouse gas emissions. Designing novel catalyst with high activity and selectivity is essential and challenging for practical applications of photothermal CO2 reduction. Herein, we report that natural halloysite nanotubes-supported Ru nanoparticles can boost the photothermal catalytic activity and selectivity of CO2 methanation under continuous flow conditions. The photothermal catalytic performance of optimized catalyst is up to 1704 mmolCH4 gcat−1 h−1 with 93% CH4 selectivity and 68% CO2 conversion, outperforming any other Ru-based catalysts in photothermal CO2 reduction. Mechanistic studies show that the outstanding catalytic performance is mainly attributed to the unique mesoporous tubular structure, excellent ability of light-to-heat and interfacial interactions between the halloysite nanotubes and Ru. This method of utilizing natural minerals as support provides a facile avenue for rational design of abundant and low-cost catalysts for efficient photothermal catalytic CO2 reduction.

Boosting full-spectrum light driven surface lattice oxygen activation of ZnMn2O4 by facet engineering for highly efficient photothermal mineralization of toluene

To improve the catalytic activity of photothermal catalysts for efficient mineralization of volatile organic compounds still keeps challenge. Herein, ZnMn2O4 with controllably exposed {010} facets (ZMO-H), {11−1} facets (ZMO-R), and {1−1−1} facets (ZMO-C) were firstly synthesized and used to unveil an essential role of facet-dependent activation of surface lattice oxygen for toluene mineralization under full-spectrum light irradiation. The experimental studies and theoretical calculations together evidenced that as compared to ZMO-R and ZMO-C, ZMO-H is favorable for activating surface lattice oxygen, owing to its relatively stronger light absorption, higher surface lattice oxygen content, and lower oxygen dissociation energy. The theoretical calculations further confirmed that toluene is more easily adsorbed by ZMO-H than by ZMO-R and ZMO-C. All these advantages have substantially afforded the toluene photothermal oxidation activity of ZMO-H. This finding confirms that surface lattice oxygen activation of catalyst by facet engineering is crucial on the photothermal oxidation of toluene.

Facile preparation of Au- and BODIPY-grafted lipid nanoparticles for synergized photothermal therapy.

Gold nanoparticles with large size exhibit preferable properties for photothermal therapy (PTT). However, the prolonged tissue retention and slow elimination of gold nanoparticles limit their therapeutic applications. Previously, gold nanoclusters carrying lipid nanoparticles (Au-LNPs) have been reported after simply mixing Au3+ with preformed diethylenetriaminepentaacetic acid lipid nanoparticles to solve this contradiction. Au-LNPs demonstrated enhanced photothermal effects in comparison to neat gold nanoparticles. To further improve the photothermal activity, we introduced the organic photothermal agent boron dipyrromethene (BODIPY) to Au-LNPs for synergistic PTT. Au- and BODIPY-grafted LNPs (AB-LNPs) were formed by simply mixing Au-LNPs with BODIPY. The BODIPY could be associated stably to Au-LNPs, and the release of BODIPY from AB-LNPs could be accelerated by laser irradiation. AB-LNPs are scalable and showed excellent photothermal effects. AB-LNPs showed enhanced cellular uptake efficiency compared to free BODIPY in 4T1 breast cancer cells. Under laser irradiation, AB-LNPs exhibited synergistic photothermal effects with significantly reduced dosage compared to monotherapy (treatments with Au-LNPs or free BODIPY alone). This study thus provides a facile and adaptive strategy for the development of a scalable and safe high-performance nanoplatform for synergistic PTT in the treatment of cancer and other diseases.

Dislocation-rich BiOI nanosheets designed by nitrogen ion implantation for improving NIR-triggered bactericidal activity

Designing high-performance antibacterial agents is crucial for efficient bacterial inactivation in environmental applications. In this study, a potential photothermocatalytic bactericidal candidate BiOI nanosheets with dislocation-rich defects are rationally constructed by employing high-energy nitrogen ion implantation engineering. The constructed BiOI produces an enhanced conductivity due to the lattice atom replacement induced by nitrogen ion implantation, which favors the separation and transfer of electron-hole and inhibits backflow of electrons, leading to boosted photocatalytic activity. Meanwhile, the photothermal activity is dramatically enhanced by controlling the ion irradiation fluence-induced dislocation density. Outstanding antibacterial properties are demonstrated by the long-term irreversible photothermal and photocatalytic destruction under near infrared (NIR) illumination. The ample theory and experiments reveal that the ion-beam implantation is a reliable technique to engineer nanomaterial photothermal catalysts, and the irradiated BiOI nanosheets are highly effective in prompting the bactericidal process.

UV-Assisted Room-Temperature Fabrication of Lignin-Based Nanosilver Complexes for Photothermal-Mediated Sterilization.

Green and controllable preparation of silver nanoparticles (AgNPs) remains a great challenge. In this work, ethanol-extracted lignin-based nanosilver composites (AgNPs@EL) were synthesized at room temperature with the assistance of ultraviolet (UV) radiation. The ethanol-extracted lignin (EL) could serve as natural dispersion carriers and reducing agents for AgNPs. The reducing ability of EL could be further improved under UV irradiation, which enables the rapid synthesis of AgNPs at room temperature. More importantly, due to the good photothermal conversion capacity of EL, AgNPs@EL exhibits remarkably enhanced photothermal performance and excellent photothermal antibacterial ability, which could cause 7.2 and 5.3 log10 CFU/mL reduction against Escherichia coli and Staphylococcus aureus, respectively, under near-infrared (NIR) irradiation (808 nm, 1.8 W/cm2) for 5 min. Furthermore, the composite film obtained by impregnating bacterial cellulose onto AgNPs@EL solution also shows significantly improved mechanical properties and photothermal antimicrobial activity. Therefore, this work may provide insights into the design of lignin-based photothermal-mediated antimicrobial materials.