Search Results (329)

The creation of innovative systems that are able to combine diagnosis and therapy is a crucial opportunity in nuclear medicine. Here, we propose a methodological and multiscale approach for the development of a theranostic platform based on AuNRs functionalized with radiopharmaceuticals. AuNRs offer a versatile and effective system due to their unique physicochemical properties and the possibility of surface functionalization with targeting molecules. Within this framework, key challenges include the functionalization of AuNRs to target the cell nucleus, the loading of AuNRs with radiopharmaceuticals, and the investigation of Auger electron emission from AuNRs under gamma irradiation. Multiscale modelling is employed to describe the behaviour of the system within the cellular environment and to predict potential radiobiological enhancement effects, including synergistic interactions between functionalized AuNRs and radiopharmaceutical agents such as ^99mTc-sestaMIBI. The experimental activity includes gamma irradiation studies, along with the structural and physical characterization of nanomaterials and in vitro biological investigations on T98G cells, to evaluate cytotoxicity and metabolic alterations, with the aim of assessing the potential synergistic effects of the combined system. Full article

Recently, photoacoustic (PA) imaging has made a significant impact on biomedical imaging, providing detailed information on tissue structure and function by integrating optical and acoustic techniques. PA imaging can provide functional information at the cellular (e.g., oxygen saturation, hemoglobin concentration, metabolic rate) and molecular levels, owing to its substantial advantages over conventional imaging techniques. PA imaging is particularly useful for neuroimaging, cancer detection, and cardiovascular studies. Over the last decade, there has been a tremendous amount of research and development dedicated to nanomaterials that are ideal for PA imaging. Examples of nanomaterials include carbon-based and gold nanorods, both of which demonstrate greatly enhanced light absorption capabilities in the near-infrared range. Therefore, the properties of these materials make them perfect for achieving deep penetration into tissues. In addition, they exhibit biocompatibility, tunable optical properties, and enhance the acoustic signal for PA imaging, resulting in greater accuracy and precision in PA results. Researchers working in this area have focused on developing nanomaterials with fabrication capabilities, enabling real-time visualization of therapeutic events and enhancing light absorption. This review critically examines recent advances in nanomaterials for PA imaging, emphasizing strategies for signal enhancement and evaluating their impact on imaging performance, including imaging depth, photostability, and signal intensity, as well as their suitability for biomedical applications. Furthermore, complementary approaches for PA signal enhancement are discussed to provide a broader perspective and guide the selection and design of effective contrast agents for clinical and preclinical use. Full article

This study investigates the properties of ZnO nanorod-based sensors and ZnO nanorods modified with tin dioxide (ZnO/SnO₂) and gold (ZnO/Au) nanoclusters and their response to low concentrations of carbon monoxide (CO). It was demonstrated that the ZnO/SnO₂(3) nanorod-based sensor exhibited the highest sensitivity (S = 1.64) to 10 ppm CO, while the ZnO/Au(3) sensor displayed the shortest response (69–207 s) and recovery (203–233 s) times. This behavior can be explained by ZnO/Au and ZnO/SnO₂ nanostructures having low activation energies (0.23–0.25 eV) and high potential barrier values (0.37–0.43 eV). Sensors based on ZnO/Au and ZnO/SnO₂ nanorods demonstrate sensitivity to 10 ppm CO at 250 °C and at 200 °C. In contrast, ZnO nanorod-based sensors are sensitive to 2 ppm CO at 250 °C. Full article

Metal-enhanced fluorescence (MEF) has found widespread application in biomedical sensing and in vivo tissue imaging systems. To enhance MEF efficiency, it is necessary to optimize the interaction between the metal nanoparticle plasmon and the fluorophore molecule. The size and shape of the nanoparticle, the nanoscale gap between the fluorescent molecule and the nanoparticle, and the excitation wavelength are critical parameters. In this study, we propose a model for a more complete and accurate description of the processes of molecular excitation and generation of the fluorescence spectral response, introducing a new concept of effective properties for the field enhancement factor, quantum yield, and fluorescence enhancement factor. The influence of the spectral properties of both the nanostructure plasmon and the fluorophore molecule on the optimal tuning of fluorescent complexes is studied. Particular attention is paid to the analysis of the spectral properties of plasmon resonance and calculations of the near-field intensity enhancement of the plasmonic nanostructure’s excitation field. Numerical results for optimizing the MEF of fluorescent complexes based on TagRFP and gold (silver) nanorod composites are presented. The advantages of the proposed model for the optimal design of new nanomaterials with unique fluorescent properties are discussed. Full article

Background: The development of plasmonic photothermal therapy (PPTT) to trigger cancer cells is often hindered by uncontrolled overheating and the lack of real-time feedback. Methods: In this study, we report the synthesis of gold nanorod-embedded mesoporous silica nanoshells (AuNR@Si) as a multifunctional theranostic platform designed for controlled hyperthermia and surface-enhanced Raman spectroscopy (SERS) monitoring. Using a layer-by-layer templating strategy, AuNRs were successfully obtained within a hollow silica architecture. Results: While AuNRs alone exhibited rapid photothermal spikes reaching 64 °C, the AuNR@Si platform moderated the photothermal response, maintaining a stable therapeutic window (41–45 °C). In vitro assays using T47D breast cancer cells demonstrated a 33% reduction in viability following irradiation. Furthermore, the structural stability of the AuNR@Si platform enabled SERS monitoring of cellular damage, identifying specific biochemical fingerprints of protein denaturation, cytochrome c release and DNA fragmentation. Conclusions: These results suggest that AuNR@Si nanoshells provide a safer, regulated approach to photothermal ablation with the added benefit of molecular detection, demonstrating proof-of-concept theranostic functionality in a luminal breast cancer model. Full article

The synthesis of continuous non-linear metal nanostructures at the micro and nanoscale remains a challenging frontier in nanotechnology due to inherent synthetic constraints. This study introduces an innovative chemical methodology for fabricating continuous rings and diverse geometries via the chemical fusion of gold nanorods (AuNRs) on a solid substrate. Initially, aqueous solutions of cetyltrimethylammonium bromide (CTAB)-coated AuNRs were deposited and dried on a solid substrate, resulting in the self-assembly of ring-like arrays. Subsequent chemical growth of the AuNRs in all dimensions was achieved using an aqueous solution of Au(I)/CTAB/Ascorbic Acid (AA), enabling their fusion into continuous structures. This approach permits the formation of arbitrary shapes by pre-arranging AuNRs, thereby opening new avenues for the exploration of non-linear nanostructures with potentially novel plasmonic and electronic properties. The capability to engineer such complex nanostructures is pivotal for advancing fields such as photonics, electronics, and sensing, where the unique optical and electronic properties of gold nanostructures can be exploited for cutting-edge applications. Furthermore, this technique shows a significant promise for the fabrication of various micro- and nanodevices and the seamless interconnection of components in integrated electronic circuits, potentially leading to more efficient and miniaturized electronic systems. The broader implications of this research are significant, offering a potential pathway to the development of nanomaterials and devices that could benefit various industries and technological processes. Full article

Plasmonic nanostructures have been widely employed to improve upconversion luminescence performance; however, their impact on excitation pathways under multi-wavelength excitation is not yet fully understood. In this work, we constructed hybrid systems composed of gold nanorod arrays and NaYF₄:Yb³⁺/Ln³⁺ (Ln = Er³⁺, Tm³⁺) upconversion nanoparticles to systematically investigate upconversion behavior under dual-wavelength excitation at 808 and 976 nm. Contrary to the expected synergistic enhancement, our experimental results demonstrate that dual-wavelength excitation in the plasmonic hybrid structures produces different responses of upconversion emission. Measurements dependent on excitation power, along with the analysis of emission intensity ratio, indicate that plasmonic coupling under dual-wavelength excitation significantly enhances dissipative pathways that compete with upconversion processes. Notably, these effects strongly depend on the intrinsic energy-level structure of the lanthanide ions. In the Er³⁺-doped system, excitation at 808 nm facilitates population of higher-lying excited states, but the overall upconversion gain remains limited. In contrast, in the Tm³⁺-doped system, plasmonic coupling markedly amplifies stimulated emission and cross-relaxation processes, causing rapid depletion of high-energy state populations and substantial suppression of luminescence. These findings elucidate the competition between upconversion and dissipation processes governing plasmon-assisted upconversion under dual-wavelength excitation and provide a physical foundation for manipulating upconversion luminescence using multiple wavelengths. Full article

Gold nanorods (AuNRs) were synthesized and optimized with the aim of obtaining strongly hydrophilic nanomaterials, suitable as a drug delivery system (DDS) for copper-based drugs. After careful purification, AuNRs were characterized by ultraviolet–visible–near-infrared spectroscopy (UV–Vis–NIR), showing two typical localized surface plasmon resonance (LSPR) bands in the range 550–750 nm. Fourier Transform Infrared (FT-IR) and high-resolution X-ray photoelectron (HR-XPS) spectroscopies verified the surface functionalization. Transmission electron microscopy (TEM) showed AuNRs with regular shape and size, with an aspect ratio (AR) of 2.6. Dynamic Light Scattering (DLS) measurements confirmed the size and the stability in water for up to 3 months. The AuNRs were conjugated with copper(I) drugs, i.e., [Cu(PTA)₄]BF₄ (PTA = 1,3,5-triaza-7-phosphadamantane). The drug loading procedures and efficiency were optimized, and the best loading was η (%) = 50 ± 7%. The non-covalent interactions of the Cu(I) complex with the AuNRs were studied by means of UV–Vis–NIR, ζ-potential, HR-TEM, FT-IR, synchrotron radiation-induced X-ray photoelectron (SR-XPS), and near-edge X-ray absorption fine structure (NEXAFS) spectroscopy measurements. The MTT assay performed on Vero E6 cells showed that AuNRs and AuNR-Cu(I) conjugates had no significant effect on cell viability, being biocompatible, causing a reduction in cell viability only after prolonged exposure. Full article

Recent advancements in nanotechnology have led to the development of multifunctional nanoplatforms that significantly enhance both cancer diagnosis and treatment. Gold-based nanoparticles, such as peptide-functionalized nanostructures and PEG-coated nanorods, offer improved tumor targeting, multimodal imaging (including photoacoustic and fluorescence), and effective photothermal therapy. Similarly, ultrafine iron oxide nanoprobes provide superior tumor imaging, while silver-based nanoparticles exhibit rapid systemic circulation, near-infrared fluorescence, and powerful photothermal properties. Titanium-based nanoplatforms enable a combination of therapies and advanced imaging methods. On the therapeutic side, polymeric nanoparticles (PNPs), silica-based platforms, PEG-based nanoparticles, and graphene oxide-based systems each offer unique advantages for targeted drug delivery and theranostics. PNPs, with tunable size, shape, and surface chemistry, enable controlled drug release and reduced side effects, while silica-based nanoplatforms improve tumor targeting and imaging. PEG-based nanoparticles enhance drug release and tumor penetration, and graphene oxide-based systems facilitate subcellular targeting and synergistic therapies. Collectively, these innovations are paving the way for more efficient, precise, and safer cancer therapies, leading to improved clinical outcomes. Full article

The combination of gold nanoparticles (AuNPs) with hydrogels has drawn significant interest in the design of smart materials as advanced platforms for biomedical applications. These systems endow light-responsiveness enabled by the AuNPs localized surface plasmon resonance (LSPR) phenomenon. In this study, we propose a nanocomposite hydrogel in which gold nanorods (AuNRs) are included in an agarose–carbomer–hyaluronic acid (AC-HA)-based hydrogel matrix to study the correlation between light irradiation, local temperature increase, and drug release for potential light-assisted drug delivery applications. The gel is obtained through a facile microwave-assisted polycondensation reaction, and its properties are investigated as a function of both the hyaluronic acid molecular weight and ratio. Afterwards, AuNRs are incorporated in the AC-HA formulation, before the sol–gel transition, to impart light-responsiveness and optical properties to the otherwise inert polymeric matrix. Particular attention is given to the evaluation of AuNRs/AC-HA light-induced heat generation and drug delivery performances under near-infrared (NIR) laser irradiation in vitro. Spatiotemporal thermal profiles and high-resolution thermal maps are registered using fiber Bragg grating (FBG) sensor arrays, enabling accurate probing of maximum internal temperature variations within the composite matrix. Lastly, using a high-steric-hindrance protein (BSA) as a drug mimetic, we demonstrate that moderate localized heating under short-time repeated NIR exposure enhances the release from the nanocomposite hydrogel. Full article

Background/Objectives: To improve the response rate of immune checkpoint inhibitors (ICIs), inducing immunogenic cell death (ICD) is a promising approach. Photothermal therapy (PTT) induces immunogenic cell death and activates anti-tumor immunity. While there are various ICD inducers, the difference in ICD induction by various modalities is poorly understood. In this study, we found previously unrecognized advantages of PTT compared to anti-cancer drugs and showed the usefulness of PTT as an anti-cancer drug-free approach to be combined with immunotherapy. Methods: Gold nanorods were synthesized as photothermal agents and added to culture medium or locally administered to tumor tissues. Mitoxantrone (MIT), an ICD inducer, and cisplatin (CDDP), a non-ICD inducer, were compared with PTT. To assess the induction of ICD, the subcellular localization and amounts of high mobility group box 1 (HMGB1) and calreticulin (CRT) were observed using immunofluorescent staining. FM3A tumor-bearing mice were treated with PTT or anti-cancer drugs, and cell death and DAMPs localization in tumor tissues were analyzed. Also, the supra-additive effect of PTT on ICI was observed. Tumor-infiltrating CD8⁺ T cells were examined to evaluate the immune status in tumor tissues. Results: In vivo assays showed that PTT induces HMGB1 release and increased expression of CRT on the cell membrane. Moreover, PTT showed a supra-additive effect in terms of therapeutic effect and anti-tumor activation when combined with an immune checkpoint inhibitor. Conclusions: In this study, we demonstrated that PTT induced ICD-related signaling and improved the response rate of ICI, which means PTT is a promising combination therapy with ICI. Full article

Nanoparticle-mediated photothermal conversion exploits the unique light-to-heat transduction properties of engineered nanomaterials to address challenges in energy, water, and healthcare. This review first examines fundamental mechanisms—localized surface plasmon resonance (LSPR) in plasmonic metals and broadband interband transitions in semiconductors—demonstrating how tailored nanoparticle compositions can achieve >96% absorption across 250–2500 nm and photothermal efficiencies exceeding 98% under one-sun illumination (1000 W·m⁻², AM 1.5G). Next, we highlight advances in solar steam generation and desalination: floating photothermal receivers on carbonized wood or hydrogels reach >95% efficiency in solar-to-vapor conversion and >2 kg·m⁻²·h⁻¹ evaporation rates; three-dimensional architectures recapture diffuse flux and ambient heat; and full-spectrum nanofluids (LaB₆, Au colloids) extend photothermal harvesting into portable, scalable designs. We then survey photothermal-enhanced thermal energy storage: metal-oxide–paraffin composites, core–shell phase-change material (PCM) nanocapsules, and MXene– polyethylene glycol—PEG—aerogels deliver >85% solar charging efficiencies, reduce supercooling, and improve thermal conductivity. In biomedicine, gold nanoshells, nanorods, and transition-metal dichalcogenide (TMDC) nanosheets enable deep-tissue photothermal therapy (PTT) with imaging guidance, achieving >94% tumor ablation in preclinical and pilot clinical studies. Multifunctional constructs combine PTT with chemotherapy, immunotherapy, or gene regulation, yielding synergistic tumor eradication and durable immune responses. Finally, we explore emerging opto-thermal nanobiosystems—light-triggered gene silencing in microalgae and poly(N-isopropylacrylamide) (PNIPAM)–gold nanoparticle (AuNP) membranes for microfluidic photothermal filtration and control—demonstrating how nanoscale heating enables remote, reversible biological and fluidic functions. We conclude by discussing challenges in scalable nanoparticle synthesis, stability, and integration, and outline future directions: multicomponent high-entropy alloys, modular photothermal–PCM devices, and opto-thermal control in synthetic biology. These interdisciplinary innovations promise sustainable solutions for global energy, water, and healthcare demands. Full article

This study evaluates energy conversion and heat transfer in a germicidal chamber employing gold nanorods (AuNRs) irradiated with an infrared laser (808 nm, 0.8 W) to generate heat via localized surface plasmon resonance. The investigation focused on the preliminary selection of chamber materials and the geometry of the bottom surface supporting the AuNRs as the heat source in a photothermoablation application. A one-way multiphysics and multiscale approach was applied, integrating nanoscale heating phenomena with a macroscale fluid and heat flow. The validated 2D numerical model shows satisfactory agreement with experimental data and is suitable for further design analyses. Computational Fluid Dynamics (CFD) simulations were conducted to determine temperature and entropy distributions, mean and maximum temperatures, and Nusselt numbers, allowing the assessment of the energy conversion process under different configurations and AuNR dimensions. The results indicate that a configuration with a gradually descending stepped structure enhances interactions between nanoparticles and the fluid, increasing the internal energy and producing elevated temperatures. Under optimal conditions, a temperature rise of approximately 75 °C was achieved. These findings demonstrate that integrating material selection, surface geometry, and nanoparticle absorbance optimization can significantly improve the efficiency of bacterial inactivation in germicidal chambers. This study provides a framework for future investigations on fully three-dimensional multiscale and multiphysical modeling, as well as a targeted AuNR design to maximize the thermal performance. Full article

This study presents the development and evaluation of multifunctional, thermoresponsive nanogels based on poly(N-vinylcaprolactam-co-N-vinylpyrrolidone) (P(NVCL-co-NVP)) with a poly(ethylene glycol) methyl ether methacrylate (PEGMA) shell and galactose (GAL) targeting ligand for colon cancer therapy. The nanogels were engineered to encapsulate two chemotherapeutic agents, curcumin (CUR) and 5-fluorouracil (5-FU), along with gold nanorods (GNRDs) to enable a synergistic chemo-photothermal treatment approach. These nanogels exhibit excellent biocompatibility and stability and a temperature-responsive drug release profile, leveraging the volume-phase transition temperature (VPTT) of the polymer network for controlled delivery. The inclusion of GNRDs permits efficient photothermal conversion upon near-infrared (NIR) irradiation, resulting in localized hyperthermia and, theoretically, improved cytotoxicity when combined with chemotherapeutics. In vitro studies on colon cancer cells demonstrated enhanced drug accumulation, photothermal ablation when the GNRD concentration was above a threshold, and superior antitumor efficacy of the CUR/5-FU-loaded systems. The effectiveness of the chemo/photothermal combination could not be demonstrated, possibly due to the low concentration of GNRD and/or the use of a single irradiation step only. This work highlights the potential of P(NVCL-co-NVP):PEGMA:GAL nanogels as versatile nanocarriers for combined chemo-photothermal therapy. A more effective chemo/photothermal combination for colon cancer treatment can be achieved through the optimization of the GNRD loading/irradiation dosage. Full article

Breast cancer is one of the most prevalent malignant tumors worldwide, with the highest incidence and mortality among women. Early precise diagnosis and the development of efficient treatment regimens remain major clinical challenges. Harnessing the programmable size, surface chemistry, and tumor microenvironment (TME) responsiveness of nanomaterials, there is tremendous potential for their applications in breast cancer diagnosis and therapy. In the diagnostic arena, nanomaterials serve as core components of novel contrast agents (e.g., gold nanorods, quantum dots, superparamagnetic iron oxide nanoparticles) and biosensing platforms, substantially enhancing the sensitivity and specificity of molecular imaging modalities—such as magnetic resonance imaging (MRI), computed tomography (CT), and fluorescence imaging (FLI)—and enabling high-sensitivity detection of circulating tumor cells and tumor-derived exosomes, among various liquid biopsy biomarkers. In therapy, nanoscale carriers (e.g., liposomes, polymeric micelles) improve tumor targeting and accumulation efficiency through passive and active targeting strategies, thereby augmenting anticancer efficacy while effectively reducing systemic toxicity. Furthermore, nanotechnology has spurred the rapid advancement of emerging modalities, including photothermal therapy (PTT), photodynamic therapy (PDT), and immunotherapy. Notably, the construction of theranostic platforms that integrate diagnostic and therapeutic units within a single nanosystem enables in vivo, real-time visualization of drug delivery, treatment monitoring, and therapeutic response feedback, providing a powerful toolkit for advancing breast cancer toward personalized, precision medicine. Despite challenges that remain before clinical translation—such as biocompatibility, scalable manufacturing, and standardized evaluation—nanomaterials are undoubtedly reshaping the paradigm of breast cancer diagnosis and treatment. Full article