Upconverting LuVO4:Nd3+/Yb3+/Er3+@SiO2@Cu2S Hollow Nanoplatforms for Self-monitored Photothermal Ablation

Nitroreductase-responsive nanoparticles for in situ fluorescence imaging and synergistic antibacterial therapy of bacterial keratitis

As bacterial keratitis progresses rapidly, prompt intervention is necessary. Current diagnostic processes are time-consuming and invasive, leading to improper antibiotics for treatment. Therefore, innovative strategies for diagnosing and treating bacterial keratitis are urgently needed. In this study, Cu2-xSe@BSA@NTRP nanoparticles were developed by loading nitroreductase-responsive probes (NTRPs) onto Cu2-xSe@BSA. These nanoparticles exhibited integrated fluorescence imaging and antibacterial capabilities. In vitro and in vivo experiments showed that the nanoparticles produced responsive fluorescence signals in bacteria within 30 min due to an interaction between the released NTRP and bacterial endogenous nitroreductase (NTR). When combined with low-temperature photothermal therapy (PTT), the nanoparticles effectively eliminated E. coli and S. aureus, achieved antibacterial efficacy above 95% and facilitated the re-epithelialization process at the corneal wound site in vivo. Overall, the Cu2-xSe@BSA@NTRP nanoparticles demonstrated potential for rapid, noninvasive in situ diagnosis, treatment, and visualization assessment of therapy effectiveness in bacterial keratitis.

Two-photon excited luminescence of structural light enhancement in subwavelength SiO2 coating europium ion-doped paramagnetic gadolinium oxide nanoparticle and application for magnetic resonance imaging

BACKGROUND

Oxides of lanthanide rare-earth elements show great potential in the fields of imaging and therapeutics due to their unique electrical, optical and magnetic properties. Oxides of lanthanide-based nanoparticles enable high-resolution imaging of biological tissues by magnetic resonance imaging (MRI), computed tomography (CT) imaging, and fluorescence imaging. In addition, they can be used to detect, treat, and regulate diseases by fine-tuning their structure and function. It remains challenging to achieve safer, efficient, and more sensitive nanoparticles for clinical applications through the structural design of functional and nanostructured rare-earth materials.

RESULT

In this study, we designed a mesoporous silica-coated core-shell structure of europium oxide ions to obtain near-infrared two-photon excitation fluorescence while maintaining high contrast and resolution in MRI. We designed enhanced 800 nm photoexcitation nanostructures, which were simulated by the finite-difference method (FDM) and finite-difference time-domain method (FDTD). The nanoparticle structure, two-photon absorption, up-conversion fluorescence, magnetic properties, cytotoxicity, and MRI were investigated in vivo and in vitro. The nanoparticle has an extremely strong optical fluorescence response and multiple excitation peaks in the visible light band under the 405 nm continuous-wave laser excitation. The nanoparticle was found to possess typical optical nonlinearity induced by two-photon absorption by ultrafast laser Z-scan technique. Two-photon excited fluorescence of visible red light at wavelengths of 615 nm and 701 nm, respectively, under excitation of the more biocompatible near-infrared (pulsed laser at 800 nm). In an in vitro MRI study, a T1 relaxation rate of 6.24 mM^-1 s^-1 was observed. MRI in vivo showed that the nanoparticles could significantly enhance the signal intensity in liver tissue.

CONCLUSIONS

These results suggest that this sample has applied potential in visible light fluorescence imaging and MRI.

Visualization of Phototherapy Evolution by Optical Imaging

Phototherapy, including photodynamic therapy (PDT) and photothermal therapy (PTT), is a non-invasive and effective approach used for cancer treatment, in which phototherapeutic agents are irradiated with an appropriate light source to produce cytotoxic reactive oxygen species (ROS) or heat to ablate cancer cells. Unfortunately, traditional phototherapy lacks a facile imaging method to monitor the therapeutic process and efficiency in real time, usually leading to severe side effects due to high levels of ROS and hyperthermia. To realize precise cancer treatment methods, it is highly desired to develop phototherapeutic agents possessing an imaging ability to evaluate the therapeutic process and efficacy in real time during cancer phototherapy. Recently, a series of self-reporting phototherapeutic agents were reported to monitor PDT and PTT processes by combining optical imaging technologies with phototherapy. Due to the real-time feedback provided by optical imaging technology, therapeutic responses or dynamic changes in the tumor microenvironment could be evaluated in a timely manner, thereby achieving personalized precision treatment and minimizing toxic side effects. In this review, we focus on the advances in the development of self-reporting phototherapeutic agents for a cancer phototherapy evaluation based on optical imaging technology to realize precision cancer treatments. Additionally, we propose the current challenges and future directions of self-reporting agents for precision medicine.

Tunable luminescence and efficient energy transfer investigation of a borosilicate phosphor KBSi2O6: Bi3+, Eu3+ with hypersensitive thermal quenching

Energy transfer between Bi³⁺ and Eu³⁺ has undergone substantial research but Bi³⁺ and Eu³⁺ co-doped luminescent materials with high energy transfer efficiency for temperature sensing are rarely investigated until now. Herein, Eu³⁺ and Bi³⁺ co-doped KBSi₂O₆ phosphors were successfully synthesized by solid-state reaction method. The phase purity structure as well as the element distribution were carefully investigated through X-ray diffraction structural refinement and energy dispersive spectrometer analysis. The characteristic luminescence property and luminescence kinetics of KBSi₂O₆: Bi³⁺, Eu³⁺ were investigated. By the large spectra overlap between the emission spectrum of Bi³⁺ and excitation spectrum of Eu³⁺, the energy transfer from Bi³⁺ to Eu³⁺ can be inferred. The corresponding decrease of the emission intensity and decay time of Bi³⁺ in KBSi₂O₆: Bi³⁺, Eu³⁺ provided direct evidence for the effective energy transfer from Bi³⁺ to Eu³⁺. The interaction and energy transfer mechanism between Bi³⁺ and Eu³⁺ ions were also studied. By increasing the Eu³⁺ concentration in KBSi₂O₆: Bi³⁺, Eu³⁺, the color-tunable emission from blue to red can be realized. KBSi₂O₆: Bi³⁺, Eu³⁺ shows hypersensitive thermal quenching behavior and the maximum absolute sensitivity (S_a) and relative sensitivity (S_r) are determined to be 1.87 %K^-1 and 2.895 %K^-1, respectively. All of the above results imply that KBSi₂O₆: Bi³⁺, Eu³⁺ phosphor can be a color-tunable phosphor for optical temperature sensing.

The role of Nd3+ concentration in the modulation of the thermometric performance of Stokes/anti-Stokes luminescence thermometer in NaYF4:Nd3

The growing popularity of luminescence thermometry observed in recent years is related to the high application potential of this technique. However, in order to use such materials in a real application, it is necessary to have a thorough understanding of the processes responsible for thermal changes in the shape of the emission spectrum of luminophores. In this work, we explain how the concentration of Nd³⁺ dopant ions affects the change in the thermometric parameters of a thermometer based on the ratio of Stokes (⁴F_3/2 → ⁴I_9/2) to anti-Stokes (⁴F_7/2,⁴S_3/2 → ⁴I_9/2) emission intensities in NaYF₄:Nd³⁺. It is shown that the spectral broadening of the ⁴I_9/2 → ⁴F_5/2, ²H_9/2 absorption band observed for higher dopant ion concentrations enables the modulation of the relative sensitivity, usable temperature range, and uncertainty of temperature determination of such a luminescent thermometer.

Near-Infrared-to-Near-Infrared Optical Thermometer BaY2O4: Yb3+/Nd3+ Assembled with Photothermal Conversion Performance

Nowadays, the construction of photothermal therapy (PTT) agents integrated with real-time thermometry for cancer treatment in deep tissues has become a research hotspot. Herein, an excellent photothermal conversion material, BaY₂O₄: Yb³⁺/Nd³⁺, assembled with real-time optical thermometry is developed successfully. Ultrasensitive temperature sensing is implemented through the fluorescence intensity ratio of thermally coupled Nd³⁺: ⁴F_j (j = 7/2, 5/2, and 3/2) with a maximal absolute and relative sensitivity of 68.88 and 3.29% K^-1, respectively, which surpass the overwhelming majority of the same type of thermometers. Especially, a thermally enhanced Nd³⁺ luminescence with a factor of 180 is detected with irradiation at 980 nm, resulting from the improvement in phonon-assisted energy transfer efficiency. Meanwhile, the photothermal conversion performance of the sample is excellent enough to destroy the pathological tissues, of which the temperature can be raised to 319.3 K after 180 s of near-infrared (NIR) irradiation with an invariable power density of 13.74 mW/mm². Besides, the NIR emission of Nd³⁺ can reach a depth of 7 mm in the biological tissues, as determined by an ex vivo experiment. All the results show the potential application of BaY₂O₄: Yb³⁺/Nd³⁺ as a deep-tissue PTT agent simultaneously equipped with photothermal conversion and temperature sensing function.

Tri-functional SERS nanoplatform with tunable plasmonic property for synergistic antibacterial activity and antibacterial process monitoring

Strategies integrating synergistic high-efficiency bacterial killing and antibacterial process monitoring capability are desirable. Herein, a tri-functional surface-enhanced Raman spectroscopy (SERS) nanoplatform, namely 4-mercaptobenzoic acid-encoded gold nanorods@silver coated with a layer of bovine serum albumin (AuNRs@Ag@4-MBA@BSA), with excellent biocompatibility, stability, tunable plasmonic property and activatable photothermal effect is introduced for Ag⁺/photothermal therapy (PTT) synergistic antibacterial activity and antibacterial process monitoring. An exogenous etchant is used to controllably model the physiological process of metallic silver biodegradation. Ag shell etching causes the surface plasmon resonance band of SERS nanotags to red-shift to near-infrared region, activates the photothermal conversion capability, and triggers PTT, which in turn accelerates Ag shell etching. The antibacterial rates for Staphylococcus aureus and Escherichia coli after 10 min treatment can achieve 99.5% and 99.9%, respectively. Furthermore, the near-field effect and ultrasensitive property render the SERS intensity decrease ratio is dependent on Ag shell etching as well as temperature rising and thus relevant to antibacterial activity. We have demonstrated a strong correlation between SERS signal and antibacterial effect, and have verified the possibility of antibacterial process monitoring in vitro using SERS-based methodology. We envision that our integrated strategy being used for in vivo high-efficiency bacterial killing and antibacterial process monitoring.

Rare-Earth Doping in Nanostructured Inorganic Materials

Impurity doping is a promising method to impart new properties to various materials. Due to their unique optical, magnetic, and electrical properties, rare-earth ions have been extensively explored as active dopants in inorganic crystal lattices since the 18th century. Rare-earth doping can alter the crystallographic phase, morphology, and size, leading to tunable optical responses of doped nanomaterials. Moreover, rare-earth doping can control the ultimate electronic and catalytic performance of doped nanomaterials in a tunable and scalable manner, enabling significant improvements in energy harvesting and conversion. A better understanding of the critical role of rare-earth doping is a prerequisite for the development of an extensive repertoire of functional nanomaterials for practical applications. In this review, we highlight recent advances in rare-earth doping in inorganic nanomaterials and the associated applications in many fields. This review covers the key criteria for rare-earth doping, including basic electronic structures, lattice environments, and doping strategies, as well as fundamental design principles that enhance the electrical, optical, catalytic, and magnetic properties of the material. We also discuss future research directions and challenges in controlling rare-earth doping for new applications.

Advances in multifunctional chitosan-based self-healing hydrogels for biomedical applications

Multifunctional self-healing hydrogels have recently attracted considerable interest in biomedical applications owing to their diverse properties, including self-healing, adhesion, conduction, antibacterial, and stimulus-response, which can meet various application requirements, ranging from wound dressings and delivery vehicles to the production of scaffolds for tissue repair and regeneration. As a natural polycationic polysaccharide with good biocompatibility, chitosan is widely used in hydrogel formation as there are many amino and hydroxyl groups along the chains that can actively participate in various physical effects and chemical reactions, which enable it to construct self-healing hydrogels and fulfill multiple functions. In this review, the formation of chitosan-based self-healing hydrogels and the related self-healing mechanism are summarized, including Schiff base, metal coordination, ionic and hydrogen bonds, hydrophobic and host-guest interactions, with a focus on the strategies for their multi-functionalization. In the last section, the applications of the chitosan-based self-healing hydrogels in the fields of wound dressings, delivery vehicles, scaffolds, and biological sensors are discussed. Overall, it is highly expected that this review could provide an insight into the prospective development of multifunctional self-healing hydrogels for biomedical applications.

Upconversion nanoparticles modified by Cu2S for photothermal therapy along with real-time optical thermometry

Highly effective photothermal conversion performance coupled with high resolution temperature detection in real time is urgently needed for photothermal therapy (PTT). Herein, ultra-small Cu₂S nanoparticles (NPs) were designed to absorb on the surface of NaScF₄: Yb³⁺/Er³⁺/Mn²⁺@NaScF₄@SiO₂ NPs to form a central-satellite system, in which the Cu₂S NPs play the role of providing significant light-to-heat conversion ability and the Er³⁺ ions in the NaScF₄: Yb³⁺/Er³⁺/Mn²⁺ cores act as a thermometric probe based on the fluorescence intensity ratio (FIR) technology operating in the biological windows. A wavelength of 915 nm is used instead of the conventional 980 nm excitation wavelength to eliminate the laser induced overheating effect for the bio-tissues, by which Yb³⁺ can also be effectively excited. The temperature resolution of the FIR-based optical thermometer is determined to be better than 0.08 K over the biophysical temperature range with a minimal value of 0.06 K at 298 K, perfectly satisfying the requirements of biomedicine. Under the radiation of 915 nm light, the Cu₂S NPs exhibit remarkable light-to-heat conversion capacity, which is proved by photothermal ablation testing of E. coli. The results reveal the enormous potential of the present NPs for PTT integrated with real-time temperature sensing with high resolution.

A Smart "Sense-and-Treat" Nanoplatform Based on Semiconducting Polymer Nanoparticles for Precise Photothermal-Photodynamic Combined Therapy

Integrated theranostic nanoplatforms with biomarker recognition and photothermal- and photodynamic (PTT/PDT) therapy is in high demand but remains challenging. Herein, a "sense-and-treat" nanoplatform based on semiconducting polymer nanoparticles (SPNs) for ratiometric bioimaging of phospholipase D (PLD) activity and PTT/PDT combined therapy was proposed. Semiconducting polymer nanoparticles (PSBTBT NPs) serve not only as photothermal agents but also as fluorescent quenchers of Rhodamine B (Rhod B) through a PLD-cleavable linker. Chlorin e6 (Ce6) was used as a photodynamic agent and fluorescence reference. The obtained nanoplatform (PSBTBT-Ce6@Rhod NPs) showed high PDT efficiency and photothermal performance upon single laser irradiation. The PTT/PDT combined therapy achieved more efficient tumor inhibition results as compared with single treatments. In addition, the overexpressed biomarker PLD in tumor tissue will cleave Rhod, leading to the fluorescence recovery of Rhod B and thus allowing the activatable fluorescence imaging of tumor and targeted phototherapy.

Remarkable bactericidal traits of a metal-ceramic composite coating elated by hierarchically structured surface

A ceramic-based coating with a hierarchical surface structure was synthesized via solid-state reaction enabled by a double cathode glow discharge technique. This innovative coating comprises two distinct layers, specifically an outer layer with a well-aligned micro-pillar array and a dense inner layer. Both are composed of a face-centered cubic Cu(Co,Ni,Fe) solid solution phase together with a spinel-type Fe(Al,Cr)2O4 oxide. This coating exhibits superhydrophobicity and, yet, a very strong adhesion to water, i.e., the so-called "rose petal effect". This coating also exhibits highly efficient antibacterial ability against both Staphylococcus aureus and Escherichia coli bacteria under both dark and visible light conditions. The excellent antibacterial property originates from the synergistic effects through the release of Cu ions coupled with photothermal activity upon light activation.

Advances in Hollow Inorganic Nanomedicines for Photothermal-Based Therapies

Nanotechnology has prompted the development of hollow inorganic nanomedicine. These medicines are now widely investigated as photothermal-based therapies for various diseases due to their high loading capacity, tuneable wavelength, relatively small size and low density. We begin this review with a brief introduction, followed by a summary of the development of imaging-guided photothermal therapy (PTT) for cancer treatment during the last three years (from 2017 to 2020). We then introduce the antibacterial effects of these medicines on some bacterial infections, in which the pathogenic bacteria can be killed by mild photothermal effects, ions and antibiotic release. Other diseases can also be treated using hollow inorganic photothermal agents. Specifically, we discuss the use of PTT for treating Alzheimer's disease, obesity and endometriosis. Finally, we share our perspectives on the current challenges and future prospects of using hollow inorganic materials in clinical PTT for various diseases.

Development of a cyan blue-emitting Ba3La2(BO3)4:Ce3+,Tb3+ phosphor for use in dental glazing materials: color tunable emission and energy transfer

Herein, we demonstrated the possibility of using Ba₃La₂(BO₃)₄:Ce³⁺,Tb³⁺ phosphors in dental glazing paste.

Temperature sensitivity modulation through changing the vanadium concentration in a La2MgTiO6:V5+,Cr3+ double perovskite optical thermometer

To fulfil the requirements of operating at low temperature in a harsh environment, the investigation on optical thermometers plays an increasingly important role. In this work, the influence of vanadium concentration on the capability of temperature readout by La2MgTiO6:V5+,Cr3+ luminescent thermometers was investigated for the first time. The presence of V3+ and V5+ was verified by XPS and absorption measurements. In the emission spectra, a blue-green emission region was assigned to both host and V5+ emission. Moreover, a spin-forbidden emission of Cr3+ ions was also detected. Vanadium ions in the +3 oxidation state do not exhibit luminescence, but play a role as a charge compensator. The highest emission intensity was obtained from the sample doped with 0.1% V. Besides, with increasing vanadium concentration, a redshift in the maximum position of the spectrum was observed corresponding to a movement from the greenish blue to yellowish green region in the CIE1931. It was shown that the relative sensitivity (Sr) and the temperature operating range can be easily modified by changing the concentration of vanadium ions. In particular, the outstanding relative sensitivities of 1.71% K-1 (at 187 K) and 1.96% K-1 (at 165 K) obtained from La2MgTiO6:0.1%V5+,Cr3+ and La2MgTiO6:0.05%V5+,Cr3+ demonstrated the enormous potential of this material for thermal sensing application.

Phototherapy-based combination strategies for bacterial infection treatment

The development of nanomedicine is expected to provide an innovative direction for addressing challenges associated with multidrug-resistant (MDR) bacteria. In the past decades, although nanotechnology-based phototherapy has been developed for antimicrobial treatment since it rarely causes bacterial resistance, the clinical application of single-mode phototherapy has been limited due to poor tissue penetration of light sources. Therefore, combinatorial strategies are being developed. In this review, we first summarized the current phototherapy agents, which were classified into two functional categories: organic phototherapy agents (e.g., small molecule photosensitizers, small molecule photosensitizer-loaded nanoparticles and polymer-based photosensitizers) and inorganic phototherapy agents (e.g., carbo-based nanomaterials, metal-based nanomaterials, composite nanomaterials and quantum dots). Then the development of emerging phototherapy-based combinatorial strategies, including combination with chemotherapy, combination with chemodynamic therapy, combination with gas therapy, and multiple combination therapy, are presented and future directions are further discussed. The purpose of this review is to highlight the potential of phototherapy to deal with bacterial infections and to propose that the combination therapy strategy is an effective way to solve the challenges of single-mode phototherapy.

Hollow Octahedral Cu2-xS/CdS/Bi2S3 p-n-p Type Tandem Heterojunctions for Efficient Photothermal Effect and Robust Visible-Light-Driven Photocatalytic Performance

Reasonable design of the nanostructure of heterogeneous photocatalysts is of great significance for improving their performance and stability. We report the design and fabrication of hollow sandwich-layered octahedral Cu_2-xS/CdS/Bi₂S₃ p-n-p type tandem heterojunctions constructed via the continuous growth deposition method on the surface of hollow octahedral Cu_2-xS with well-defined structures and interfaces. The unique hollow sandwich nanostructure has a large specific surface area and abundant reaction sites and enhances the separation and transfer of photogenerated carriers. In addition, the formation of a p-n-p heterojunction coupled with the surface plasmon resonance effect of Cu_2-xS could also aid in photocatalytic H₂ evolution performance and photocatalytic degradation efficiency. Under vis-NIR light irradiation, the optimized Cu_2-xS/CdS/Bi₂S₃ photocatalyst displays a notable H₂ production rate of 8012 μmol h^-1 g^-1, and 2,4-dichlorophenol is almost completely photocatalytically degraded in 150 min. This strategy and rational design offer a new path toward the design of specific nanocatalysts with enhanced activity and stability and challenging reactions.

Simultaneous Enhancement and Modulation of Upconversion by Thermal Stimulation in Sc2Mo3O12 Crystals

Rational control of photoluminescence against a change in temperature is important for fundamental research and technological applications. Herein, we report an anomalous temperature dependence of upconversion luminescence in Yb/Ho co-doped Sc₂Mo₃O₁₂ crystals. By leveraging negative thermal expansion of the crystal lattice, energy transfer between the lanthanide dopants is promoted as the temperature is increased from 303 to 573 K, resulting in an ∼5-fold enhancement of the emission. Meanwhile, the emission profile is also substantially altered due to the concurrent thermal quenching of selective energy states, corresponding to a clear shift in color from green to red. Via correlation of the red-to-green emission intensity ratio of Ho³⁺ dopant ions with temperature, a ratiometric luminescence thermometer is constructed with a maximum sensitivity of 2.75% K^-1 at 543 K. As the Sc₂Mo₃O₁₂ crystals are thermally stable and nonhygroscopic, our findings highlight a general approach for highly reversible control of upconversion by temperature in ambient air.

Facile synthesis of polypyrrole-rhodamine B nanoparticles for self-monitored photothermal therapy of cancer cells

Photothermal therapy following microscopic temperature detection can avoid overheating effects or insufficient heating, and thus improve therapeutic efficacy. In this study, biocompatible dual-functional nanoparticles (NPs) are constructed from polypyrrole (PPy) and rhodamine B (RB) by a one-step modified polymerization method. The polypyrrole serves as a photothemal agent, and rhodamine B acts as a temperature-sensing probe. The polypyrrole-rhodamine B (PPy-RB) NPs possess a high photothermal effect on irradiation by 808 nm laser, and a competent temperature sensitivity for the real-time temperature monitoring based on the emission intensity response of rhodamine B. After acting on HepG2 cells, the PPy-RB NPs can effectively induce cancer cell death, and the microscopic temperature is monitored by fluorescence feedback from rhodamine B during PTT by laser confocal microscopy. Hence, the proposed approach can supply a facile and promising way for the fabrication of effective theranostic nanoplatforms assisted by self-monitoring of cancer therapeutic processes.

Luminescent properties and ratiometric optical thermometry of Ln-BDC-F4 compounds

A series of luminescent lanthanide compounds with 2, 3, 5, 6-tetrafluoro-1, 4-benzenedicarboxylate (H₂BDC-F₄) acting as the organic ligand have been synthesized by solvothermal reaction. The terbium compound (C1: Tb-BDC-F₄) and europium compound (C7: Eu-BDC-F₄) exhibit intense green and red luminescence respectively upon excitation of the ligand at room temperature, which suggests that H₂BDC-F₄ ligand can sensitize Tb³⁺ and Eu³⁺ ions effectively. The emitting color of the mixed lanthanide compounds is tunable from green to red in the mixed lanthanide compounds Tb_xEu_1-x-BDC-F₄ (x = 0.3%, 0.5%, 0.7%, 1%, and 2%), which is caused by energy transfer from Tb³⁺ to Eu³⁺. The self-reference ratiometric optical thermometry was realized by fluorescence intensity ratio between Tb³⁺ green emission (∼544 nm) and Eu³⁺red emission (∼ 619 nm). The maximum relative sensitivity S_R,max is 0.76%K^-1@50 K. Furthermore, the emitting color of C5: Eu_0.01Tb_0.99-BDC-F₄ could be tuned from green to orange by temperature in the range of 50 to 300 K. It allows the mixed Eu/Tb-BDC-F₄ compounds to be potentially used as sensitive luminescent materials to directly imagine the temperature distribution.

Yolk–shell structured Bi2SiO5:Yb3+,Ln3+ (Ln = Er, Ho, Tm) upconversion nanophosphors for optical thermometry and solid-state lighting

Bi₂SiO₅:Yb³⁺,Er³⁺ yolk–shell nanophosphors have been successfully synthesized, which are expected to find important applications in optical thermometry and solid-state lighting.

Nanomaterials with a photothermal effect for antibacterial activities: an overview

Nanomaterials and nanotechnologies have been expected to provide innovative platforms for addressing antibacterial challenges, with potential to even deal with bacterial infections involving drug-resistance. The current review summarizes recent progress over the last 3 years in the field of antibacterial nanomaterials with a photothermal conversion effect. We classify these photothermal nanomaterials into four functional categories: carbon-based nanoconjugates of graphene derivatives or carbon nanotubes, noble metal nanomaterials mainly from gold and silver, metallic compound nanocomposites such as copper sulfide and molybdenum sulfide, and polymeric as well as other nanostructures. Different categories can be assembled with each other to enhance the photothermal effects and the antibacterial activities. The review describes their fabrication processes, unique properties, antibacterial modes, and potential healthcare applications.

Infrared excited Er3+/Yb3+ codoped NaLaMgWO6 phosphors with intense green up-conversion luminescence and excellent temperature sensing performance

Application of an ultra-sensitive temperature sensor in solid-state lighting and detection of chip temperature.

Tunable color emission based on the activator shell thickness of multilayer core–shell nanoparticles under double NIR excitation

Rare earth luminescent nanomaterials are hot topic due to their unique fluorescence properties. Effective spectral regulation could be achieved by adjusting the coating thickness to affect the energy transfer process in core–shell structure.