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Bone metastasis remains a clinical challenge and is still considered incurable. While nanoparticles-based drug delivery and photothermal therapy (PTT) show promise in treating subcutaneous solid tumor, their therapeutic outcome in treating bone metastasis is limited, due to the inaccessibility of bone metastatic site and the complexity of bone metastasis. Herein, we reported a simple nanoplatform composed of thermo-sensitive liposomes (TSL) and gold nanorods (GNR) to treat bone metastasis through improved chemotherapy combined with GNR-assisted PTT. Lipid combination of TSL was firstly tailored to regulate its stability under physiological condition as well as its sensitivity in responding to PTT-caused mild hyperthermia. The obtained TSL with loaded drug was then combined with GNR to form the nanoplatform through unsophisticated incubation. Cell experiments revealed that upon near-infrared (NIR) irradiation, the nanoplatform effectively inhibited the viability and migration ability of tumor cells through PTT, PTT-triggered thermo-sensitive drug release, and PTT-augmented sensitivity of tumor cells to drug. In a murine model of bone metastasis, the nanoplatform enabled effective delivery of loaded drug and GNR to bone metastatic site for rapid drug release upon local NIR irradiation. Through killing tumor cells and rebalancing the turnover of osteoclasts and osteoblasts, the nanoplatform largely preserved bone structure for pain relief and survival extension. Inspired by the simplicity of nanoplatform acquirement and treatment operation, the strategy of liposomes-based thermo-sensitive drug delivery in combination with GNR-assisted PTT is considered greatly promising in treating bone metastasis.

4-Chlorophenoxyacetic acid (4-CPA), a synthetic plant regulator, has been banned due to its cumulative toxicity to humans. However, unqualified sampling remains common in the market. To address the poor sensitivity of 4-CPA antibodies reported previously, a highly sensitive monoclonal antibody specific to 4-CPA was produced by redesigning and synthesizing a novel hapten in this study. Additionally, a visual colorimetric immunosensor based on TMB2+ mediated etching of gold nanorods (Au NRs) was developed. The ∆λ of the localized surface plasmon resonance (LSPR) peak exhibited a linear dependence on the 4-CPA concentration in the range of 0.2–6.25 ng mL−1, with a low limit of detection (LOD) of 0.2 ng mL−1. Recovery tests (85.0% to 108%) and HPLC validation demonstrated the immunosensor's accuracy and precision. This visual colorimetric immunosensor illustrates significant potential for rapid detection of 4-CPA in biological environments. [ABSTRACT FROM AUTHOR]

Due to the increasing occurrence of antibiotic-resistant bacterial strains worldwide, there is an urgent need for developing antibiotic-independent strategies to combat bacterial infections. In this study, we developed a modular approach for trapping, retaining, and killing bacteria by means of porous, poly-(lactic-co-glycolic acid) (PLGA)-based microcapsules with integrated gold nanorods (AuNRs). AuNRs were coated with thiol-functionalized PLGA beforehand to ensure efficient integration into the hydrophobic microcapsule shells. For the efficient generation of AuNR-functionalized microcapsules, we designed and developed a fast and reliable one-pot bulk emulsification production method. When exposing the AuNR-decorated microcapsules to near-infrared light, both motile and nonmotile bacteria were killed in a highly localized manner due to AuNR-generated heat. Importantly, fibroblast cell viability tests performed with AuNR-decorated microcapsules revealed good biocompatibility of the system. Such a modular antibacterial system can be employed in various applications, including, but not limited to, implant coatings, flushing solutions, and sewage treatment. [ABSTRACT FROM AUTHOR]

Gold nanorods (AuNRs), as an important type of gold nanomaterials, have attracted much attention in the nano field. Compared with gold nanoparticls, AuNRs have broader application potential due to their tunable localized surface plasmon resonance properties and anisotropic shapes. Yet, conventional synthesis methods using surfactants have limited the use of AuNRs in a variety of fields such as biomedical applications, plasma‐enhanced fluorescence, optics and optoelectronic devices. To solve this problem and improve the stability and biocompatibility of AuNRs, researchers in recent years have used surface modification and functionalization to modify AuNRs, among which the introduction of organic ligands to prepare organic/gold hybrid nanorods has become an effective strategy. Organic materials have better toughness and easy processing, and by introducing organic ligands into the surface of AuNRs, the molecular‐level composite of organic and inorganic materials can be realized, thus obtaining hybrid nanorods with excellent properties. This paper reviews the research progress of hybrid nanocomposites, and introducing the synthesis methods of AuNRs and the development of surface ligand modification, then summarises the applications of a wide variety of ligands. Also, the advantages and disadvantages of different ligands and their roles in further self‐assembly processes are discussed. [ABSTRACT FROM AUTHOR]

Albumin-coated gold nanoparticles display potential biomedical applications, including cancer research, infection treatment, and wound healing; however, elucidating their interaction with normal cells remains an area with limited exploration. In this study, gold nanorods (GNR) were prepared and coated with bovine serum albumin (BSA) to produce GNR-BSA. The functionalized nanoparticles were characterized based on their optical absorption spectra, morphology, surface charge, and quantity of attached protein. The interaction between GNR-BSA and BSA with normal cells was investigated using human dermal fibroblasts. The cytotoxicity test indicated cell viability between ~63–95% for GNR-BSA over concentrations from 30.0 to 0.47 μg/mL and ~85–98% for BSA over concentrations from 4.0 to 0.0625 mg/mL. The impact of the GNR-BSA and BSA on cell migration potential and wound healing was assessed using scratch assay, and the modulation of cytokine release was explored by quantifying a panel of cytokines using Multiplex technology. The results indicated that GNR-BSA, at 10 μg/mL, delayed the cell migration and wound healing 24 h post-treatment compared to the BSA or the control group with an average wound closure percentage of 6% and 16% at 6 and 24 h post-treatment, respectively. Multiplex analysis revealed that while GNR-BSA reduced the release of the pro-inflammatory marker IL-12 from the activated fibroblasts 24 h post-treatment, they significantly reduced the release of IL-8 (p < 0.001), and CCL2 (p < 0.01), which are crucial for the inflammation response, cell adhesion, proliferation, migration, and angiogenesis. Although GNR-BSA exhibited relatively high cell viability towards human dermal fibroblasts and promising therapeutic applications, toxicity aspects related to cell motility and migration must be considered. [ABSTRACT FROM AUTHOR]

Surface plasmon resonance of precious metal gold nanorods can be tuned by controlling the aspect ratio, and they find widespread applications in biotechnology, imaging, sensing, optoelectronics, photonics, and catalysis. Here, a method is proposed for the controlled etching of gold nanorods within mesoporous silica shells by using a certain concentration of H2O2 at room temperature. In the experiments, the amount of HCl is varied to adjust the acidity and/or change the amount of H2O2 to control the speed of corrosion, achieving controllable adjustment of the aspect ratio of the gold nanorods. The extinction spectra show that under the action of H2O2 and HCl, the longitudinal plasmonic resonance of the gold nanorods shifted to shorter wavelengths, and the intensity of the longitudinal plasmonic resonance decreased. The more hydrochloric acid or hydrogen peroxide added, the faster the corrosion rate of the gold nanorods, and the faster the blue shift of the longitudinal plasmonic resonance. In addition, the intensity of the extinction spectra at 320 nm increased linearly versus time, which can also be used to monitor the etching process. By corroding gold nanorods to control the plasmonic resonances, gold nanorods can find broader applications. [ABSTRACT FROM AUTHOR]

Anti-Stokes Raman thermometry, a rapidly evolving field in Raman spectroscopy, was investigated for in situ cellular temperature measurementsa critical aspect in photothermal cancer therapy. In this study, multiwalled carbon nanotubes decorated with gold nanorods (MWCNTs-GNRs) were employed as nanothermometer probes. Characterization involved the analysis of individual Raman spectra acquired at various powers and initial temperatures. The changes observed in the Raman spectra of MWCNTs-GNRs, particularly in response to variations in temperature and excitation power, provide the necessary information to develop a reliable Raman thermometry. This methodology facilitated the extraction of the intrinsic photothermal heating coefficient of MWCNTs-GNRs, offering essential insights into their thermometric properties. An evaluation was extended to incubating MWCNTs-GNRs with prostate cancer PC3 cell lines, where anti-Stokes and Stokes signals were measured at different laser powers to assess in situ cellular temperatures. Temperature maps for a selected area were generated for MWCNTs-GNRs and a single PC3 cell incubated with MWCNTs-GNRs with data standard error analysis performed to indicate a certain level of reliability in temperature measurement accuracy. Cell viability was determined through trypan blue assays, and the obtained temperatures were correlated with viability outcomes at different laser powers. Our investigation encompassed a temperature range spanning 60–100 °C, transcending the critical temperature threshold of 50 °C, which is associated with inducing cell demise. The study highlights the potential of MWCNTs-GNRs as nanothermometer probes for targeted photothermal therapies. [ABSTRACT FROM AUTHOR]

Chemotherapy treatment outcomes are severely restricted by multidrug resistance (MDR), in which tumors develop a multiple cross‐resistance toward drug involving the pump and nonpump resistance mechanisms, resulting in drug efflux and defending against drug toxicity. Herein, we constructed a pH and near infrared (NIR) light responsive nanomedicine DOX@FG based on gold nanorods (GNRs) that demonstrated the potential to improve chemotherapy outcomes by overcoming MDR. DOX@FG was constructed by conjugating folic acid (FA) and doxorubicin (DOX) derivatives onto GNRs, where the DOX derivatives possessed an acid‐labile hydrazone bond. Stimulated by the acidic media in endocytic organelles, DOX@FG exhibited a responsive dissociation for the controlled release of chemotherapeutic DOX. Surprisingly, we found the mild photothermal effect elicited by GNRs under NIR irradiation simultaneously inhibited the pump and nonpump resistance mechanisms, enhancing the intracellular DOX accumulation and sensitizing the cancer cells to DOX, collectively amplify the chemotherapy efficacy and delay the MCF‐7/ADR breast tumor growth. This intelligent DOX@FG nanomedicine with the potential for two‐pronged reversal of MDR may provide a prospective way to encourage chemotherapy efficacy. [ABSTRACT FROM AUTHOR]

Plasmonic photothermal therapy (PPTT) involves the use of nanoparticles and near-infrared radiation to attain a temperature above 50 °C within the tumor for its thermal damage. PPTT is largely explored for superficial tumors, and its potential to treat deeper subsurface tumors is dealt feebly, requiring the assessment of thermal damage for such tumors. In this paper, the extent of thermal damage is numerically analyzed for PPTT of invasive ductal carcinoma (IDC) situated at 3–9 mm depths. The developed numerical model is validated with suitable tissue-tumor mimicking phantoms. Tumor (IDC) embedded with gold nanorods (GNRs) is subjected to broadband near-infrared radiation. The effect of various GNRs concentrations and their spatial distributions [viz. uniform distribution, intravenous delivery (peripheral distribution) and intratumoral delivery (localized distribution)] are investigated for thermal damage for subsurface tumors situated at various depths. Results show that lower GNRs concentrations lead to more uniform internal heat generation, eventually resulting in uniform temperature rise. Also, the peripheral distribution of nanoparticles provides a more uniform spatial temperature rise within the tumor. Overall, it is concluded that PPTT has potential to induce thermal damage for subsurface tumors, at depths of upto 9 mm, by proper choice of nanoparticle distribution, dose/concentration and irradiation parameters based on the tumor location. Moreover, intravenous administration of nanoparticles seems a good choice for shallower tumors, while for deeper tumors, uniform distribution is required to attain the necessary thermal damage. In the future, the algorithm may be extended further, involving 3D patient-specific tumors and through mice model-based experiments. [ABSTRACT FROM AUTHOR]

Dou Zhang,1,2,&ast; Xuyi Liu,1,2,&ast; Xiong Li,3,&ast; Xinyi Cai,1,2 Zhenying Diao,1,2 Long Qiu,1,2 Xuelin Chen,1,2 Yuyu Liu,1,2 Jianbo Sun,1 Daxiang Cui,1,4 Qiaoyuan Ye,5 Ting Yin1,2 1Research Center of Nano Technology and Application Engineering, The First Dongguan Affiliated Hospital, School of Pharmacy, Guangdong Medical University, Dongguan, Guangdong, 523808, People’s Republic of China; 2Dongguan Biomedical Nano Engineering Technology Research Center, Guangdong Medical University, Dongguan, Guangdong, 523808, People’s Republic of China; 3Department of Pharmacy, Zhuhai People’s Hospital (Zhuhai Hospital Affiliated with Jinan University), Zhuhai, Guangdong, 519000, People’s Republic of China; 4School of Sensing Science and Engineering, School of Electronic Information and Electrical Engineering, Shanghai Jiao Tong University, Shanghai, 200240, People’s Republic of China; 5Department of Dermatology and Venereology, Second Clinical Medical College of Guangdong Medical University, Dongguan, Guangdong, 523808, People’s Republic of China&ast;These authors contributed equally to this workCorrespondence: Qiaoyuan Ye, Department of Dermatology and Venereology, Second Clinical Medical College of Guangdong Medical University, Dongguan, Guangdong, 523808, People’s Republic of China, Email 13650248189@163.com Ting Yin, Research Center of Nano Technology and Application Engineering, School of Pharmacy, Guangdong Medical University, Dongguan, Guangdong, 523808, People’s Republic of China, Email wsyt132@163.comPurpose: Melanoma is a highly aggressive and dangerous malignant skin tumor and there is an urgent need to develop effective therapeutic approaches against melanoma. The main objective of this study was to construct a multifunctional nanomedicine (GNR@PEG-Qu) to investigate its therapeutic effect on melanoma from the oxidative stress pathway.Methods: First, the nanomedicine GNR@PEG-Qu was synthesized and characterized, and its photothermal and antioxidant properties were confirmed. In addition, in vivo imaging capabilities were observed. Finally, the tumor inhibitory effects of GNR@PEG-Qu in vivo and in vitro as well as its biosafety were observed.Results: GNR@PEG-Qu shows good photothermal and anti-oxidation properties. Following exposure to 1064 nm laser irradiation in the second near-infrared II (NIR-II) window, GNR@PEG-Qu shows anti-tumor ability through low-temperature photothermal therapy (PTT) adjuvant drug chemotherapy. GNR@PEG-Qu makes full use of the antioxidant capacity of quercetin, reduces ROS levels in melanoma, alleviates oxidative stress state, and achieves “oxidative stress avoidance” at the tumor site. Quercetin can also downregulate the expression of the heat shock protein Hsp70, which will improve the thermal sensitivity of the tumor site and enhance the efficacy of low-temperature PTT.Conclusion: GNR@PEG-Qu nanoagent exhibits synergistic treatment and high tumor inhibition effects, which is a promising strategy developed to achieve oxidative stress avoidance and synergistic therapy of melanoma using quercetin (Qu)-coated gold nanorod (GNR@PEG).Keywords: melanoma, gold nanorods, quercetin, chemo-photothermal therapy, oxidative stress

Héctor M Ramos-Zaldívar,1 Iva Polakovicova2,3 ,† Edison Salas-Huenuleo,4 Claudia P Yefi,5 David Silva-Ancahuail,2,6 Pedro Jara-Guajardo,2,6 Juan Esteban Oyarzún,7,8 Álvaro Neira-Troncoso,3,9 Patricia V Burgos,9 Viviana A Cavieres,9 Eloísa Arias-Muñoz,9 Carlos Martínez,10 Ana L Riveros,2,6 Alejandro H Corvalán,2,3 Marcelo J Kogan,2,6 Marcelo E Andia7,8 1Doctoral Program in Medical Sciences, Faculty of Medicine, Pontificia Universidad Católica de Chile, Santiago, Chile; 2Advanced Center for Chronic Diseases (ACCDiS), Santiago, Chile; 3Department of Hematology and Oncology, Faculty of Medicine, Pontificia Universidad Católica de Chile, Santiago, Chile; 4Advanced Integrated Technologies SpA, (AINTECH), Santiago, Chile; 5Escuela de Medicina Veterinaria, Facultad de Ciencias de la Naturaleza, Universidad San Sebastián, Santiago, Chile; 6Departamento de Química Farmacológica y Toxicológica, Facultad de Ciencias Químicas y Farmacéuticas, Laboratorio de Nanobiotecnología, Universidad de Chile, Santiago, Chile; 7Millennium Institute for Intelligent Healthcare Engineering, Santiago, Chile; 8Biomedical Imaging Center, School of Medicine, Pontificia Universidad Católica de Chile, Santiago, Chile; 9Centro de Biología Celular y Biomedicina (CEBICEM), Facultad de Medicina y Ciencia, Universidad San Sebastián, Santiago, Chile; 10Experimental Surgery and Simulation Center, Department of Digestive Surgery, Clinic Hospital, School of Medicine, Pontificia Universidad Católica de Chile, Santiago, Chile†Iva Polakovicova passed away on October 12, 2020Correspondence: Héctor M Ramos-Zaldívar, Email hmramos@uc.clIntroduction: The meningeal lymphatic vessels have been described as a pathway that transports cerebrospinal fluid and interstitial fluid in a unidirectional manner towards the deep cervical lymph nodes. However, these vessels exhibit anatomical and molecular characteristics typical of initial lymphatic vessels, with the absence of surrounding smooth muscle and few or absent valves. Given its structure, this network could theoretically allow for bidirectional motion. Nevertheless, it has not been assessed as a potential route for nanoparticles to travel from peripheral tissues to the brain.Methods: We employed superparamagnetic iron oxide nanoparticles (SPIONs), exosomes loaded with SPIONs, gold nanorods, and Chinese ink nanoparticles. SPIONs were prepared via chemical coprecipitation, while exosomes were isolated from the B16F10 melanoma cell line through the Exo-Spin column protocol and loaded with SPIONs through electroporation. Gold nanorods were functionalized with polyethylene glycol. We utilized C57BL/6 mice for post-mortem and in vivo procedures. To evaluate the retrograde directional flow, we injected each nanoparticle solution in the deep cervical lymph node. The head and neck were fixed for magnetic resonance imaging and histological analysis.Results: Here we show that extracellular vesicles derived from the B16F10 melanoma cell line, along with superparamagnetic iron oxide nanoparticles, gold nanorods, and Chinese ink nanoparticles can reach the meningeal lymphatic vessels and the brain of C57BL/6 mice after administration within the deep cervical lymph nodes post-mortem and in vivo, exclusively through lymphatic structures.Discussion: The functional anatomy of dural lymphatics has been found to be conserved between mice and humans, suggesting that our findings may have significant implications for advancing targeted drug delivery systems using nanoparticles. Understanding the retrograde transport of nanoparticles through the meningeal lymphatic network could lead to novel therapeutic approaches in nanomedicine, offering new insights into fluid dynamics in both physiological and neuropathological contexts. Further research into this pathway may unlock new strategies for treating neurological diseases or enhancing drug delivery to the brain.Keywords: extracellular vesicles, SPIONs, gold nanorods, Chinese ink, meningeal lymphatic vessels, nanomedicine

[Display omitted] Cancer immunotherapy has emerged as a potent treatment strategy by harnessing the host immune system to target cancer cells. However, challenges including low tumor vaccine immunogenicity and tumor heterogeneity hinder its clinical efficacy. To address these issues, we propose a novel nanoplatform integrating photothermal material gold nanorods (GNRs) with polyphenols for enhanced immunotherapy efficacy via photothermal therapy. Polyphenols, natural compounds with phenolic hydroxyl groups, are known for their ability to bind tightly to various molecules, making them ideal for antigen capture. We synthesized GNRs modified with polyphenols (GNR-PA and GNR-GA) and demonstrated their ability to induce immunogenic cell death upon laser irradiation, releasing tumor-associated antigens (TAAs). The surface polyphenols on GNRs effectively captured released TAAs to shield them from clearance. In vivo studies confirmed increased accumulation of GNR-GA in lymph nodes and enhanced dendritic cell maturation, leading to promoted effector T cell infiltration into tumors. Furthermore, treatment combined with PD-1/PD-L1 pathway blockade demonstrated potent tumor regression and systemic immunotherapy efficacy. Our findings highlight the potential of this photothermal nanoplatform as a promising strategy to overcome the limitations of current cancer immunotherapy approaches and improve therapeutic outcomes. [ABSTRACT FROM AUTHOR]

[Display omitted] The Enhanced Permeability and Retention (EPR) effect, an elevated accumulation of drugs and nanoparticles in tumors versus in normal tissues, is a widely used concept in the field of cancer therapy. It assumes that the vasculature of solid tumors would possess abnormal, leaky endothelial cell barriers, allowing easy access of intravenous-delivered drugs and nanoparticles to tumor regions. However, the EPR effect is not always effective owing to the heterogeneity of tumor endothelium over time, location, and species. Herein, we introduce a unique nanoparticle-based approach, using MUC18-targeted gold nanorods coupled with mild hyperthermia, to specifically enhance tumor endothelial permeability. This improves the efficacy of traditional cancer therapy including photothermal therapy and anticancer drug delivery by increasing the transport of photo-absorbers and drugs across the tumor endothelium. Using single cell imaging tools and classic analytical approaches in molecular biology, we demonstrate that MUC18-targeted gold nanorods and mild hyperthermia enlarge the intercellular gaps of tumor endothelium by inducing circumferential actin remodeling, stress fiber formation, and cell contraction of adjacent endothelial cells. Considering MUC18 is overexpressed on a variety of tumor endothelium and cancer cells, this approach paves a new avenue to improve the efficacy of cancer therapy by actively enhancing the tumor endothelial permeability. [ABSTRACT FROM AUTHOR]

Near‐infrared laser‐activated gold nanorods (AuNRs) with excellent photothermal property and tunable surface functionalization are considered as an ideal platform for biomedical applications. However, bare AuNRs have cytotoxicity against normal cells and are prone to agglomeration during laser irradiation. Herein, multivalent polymer‐functionalized AuNRs (AuNRs@pDMAEMA‐C4) was constructed as a highly stable and biocompatible photothermal agent for enhanced antibacterial therapy. The functionalized polymer was synthetized via the reversible addition‐fragmentation chain transfer polymerization and subsequently quaternized. Moreover, positively charged AuNRs@pDMAEMA‐C4 can easily capture the bacterial surface via electrostatic interactions. The integration of photothermal therapy of AuNRs and chemotherapy of functionalized polymer can achieve enhanced antibacterial effects. Under 808 nm laser irradiation, AuNRs@pDMAEMA‐C4 possessed excellent photothermal conversion capability and can kill gram‐positive and gram‐negative bacteria. Study of the antibacterial mechanism indicated that the antibacterial action of the prepared photothermal antibacterial agent can cause serious damage of the bacterial outer membranes, result in cytoplasm leakage and bacterial death. The nanocomposites combining with near‐infrared laser irradiation can facilitate rapid healing of bacteria‐infected wound by rat model of wound infection and histological analysis of the wound tissues. These results suggest that the surface functionalization can be used as potential strategy to fabricate light‐activated therapeutic agent for biomedical applications. [ABSTRACT FROM AUTHOR]

The creation and modulation of chirality in nanomaterials is a well‐established and widely applied concept. Nevertheless, the direct approach of dynamically tuning their morphological asymmetry at the nanoscale to reveal their optical asymmetry variations is yet less well‐implemented. The helical templating of nanomaterials within a cholesteric liquid crystal (CLC) host and the exploitation of their optical asymmetry change in conjunction with the host represent a means of circumventing technological limitations. In this study, a blending approach is employed to investigate the helical assemblies of gold nanorods (Au NRs) within a photo‐tunable CLC host, followed by their morphological asymmetry modulation through the use of UV irradiation. The results demonstrated that the optical asymmetry of the Au NRs helical assemblies increased in response to a reduction in pitch and the distance between the Au NRs, regardless of the azimuthal variations. Furthermore, the Au NRs blended with CLCs exhibited excellent and stable reflective properties comparable to those of conventional CLCs. Additionally, they can modulate the light flux of incident light at NIR wavelengths. The integrated modulation of reflection and transmission by Au NRs helical assemblies and CLC hosts represents a promising avenue for future research in the field of multi‐level information encryption. [ABSTRACT FROM AUTHOR]

This work presents new anisotropic growth‐directing copolymers suitable for the seed‐mediated growth of gold nanorods (GNRs). Copolymers with different architectures are studied. They all contain dimethylaminomethyl methacrylate (DMAEMA) functionalized with 1‐bromohexadecane (BHD) as the vital component. For the synthesis of the different copolymers, the photo‐iniferter reversible addition–fragmentation chain transfer (photoRAFT) polymerization is used, where DMAEMA is combined with a lower critical solution temperature (LCST) polymer block for better solubility after the functionalization. The results show that the presented copolymers can induce anisotropic growth of gold nanoparticles. Additionally, the influence of the LCST of the water‐soluble block and the temperature of the growth solution on the GNR synthesis are investigated. Furthermore, the plasmonic behavior of the resulting GNRs solution is investigated at temperatures around the LCST of the copolymer. [ABSTRACT FROM AUTHOR]

Gaseous elemental mercury (GEMHg0(g)) is a highly toxic global pollutant with environmental and human health effect concerns. Monitoring the GEM released in gold mining operation regions is extremely necessary. Herein, we develop an indirect surface-enhanced Raman scattering (SERS)-miniaturized sensor for the direct detection of Hg0(g) using gold nanorods (AuNRs) and rhodamine 6G as a probe molecule. SERS spectra show a suppressed signal after exposure to Hg0(g) in different concentrations caused by the morphologic transition of the nanorods to spheres. Discrete dipole approximation (DDA) and density functional theory (DFT) simulations reveal that the energetic phenomena involved during the Au–Hg amalgam formation process can lead to drastic changes in the AuNR's plasmonic characteristic, suppressing the SERS signal. This effect is the key to achieving the high performance to detect Hg0(g) until 0.08 μg. Additionally, the SEM-EDS results confirmed the AuNR's morphological changes after exposure to Hg0(g), and principal component analysis and root-mean-square error reveal the high sensitivity, mainly for the lower amount of Hg0(g) (0.08–1.02 μg), corroborating the DDA and DFT simulations whose Au–Hg alloy formation on the AuNR's surface is energetically more favorable, occurring more quickly and efficiently than the diffusion process. Moreover, these results show nanorod structures are more efficient than spherical ones. [ABSTRACT FROM AUTHOR]

Gold nanorods (AuNRs) are emerging metallic nanoparticles utilized to generate heat for photothermal therapy (PTT) in cancer. The tunable plasmonic properties of AuNRs make them a remarkable candidate for hyperthermia. However, the cytotoxicity of AuNRs limits its biological applicability due to the existence of cetyltrimethylammonium bromide (CTAB) on the surface as a common surfactant. In this study, AuNRs are synthesized by seed‐mediated growth and then the optical properties are optimized by altering AgNO3 concentration. Afterward, CTAB is replaced with biopolymers which are BSA:Dextran and BSA:Guar Gum conjugates resulting in enhanced cellular viability, enabling to use of them as biologically relevant photothermal agents. The biocompatibility of AuNRs is improved to utilize them at high concentrations for laser studies, in which similar heat generation success of CTAB‐ and biopolymer‐coated AuNRs are shown for potential PTT applications. CTAB and biopolymer‐coated AuNRs in concentrations of 0.5 and 1 mg mL−1 are irradiated under NIR light at 808 nm laser at 0.5, 0.75, and 1 W cm−2 for 300 s. The biopolymer‐coated gold nanorods with different coatings preserve photothermal properties while reducing the cytotoxicity effects of CTAB and thus they are promising photothermal agents for potential PTT. [ABSTRACT FROM AUTHOR]

A versatile method is invented to self‐assemble gold nanoparticles (GNPs) into nanoclusters (NCs) of various morphologies. By storing the particles in toluene, a highly non‐polar solvent, under conditions that ensure particle stability, the success rate of subsequent assembly can be enhanced. Additionally, conducting particle self‐assembly at a stirring speed of 200 rpm allows the NCs to maintain a spherical shape. The relative standard deviation (RSD) of Raman spectral peaks of multiple NCs used as surface‐enhanced Raman spectroscopy (SERS) substrates is calculated to be less than 10%, effectively addressing the issue of low repeatability when using NCs as SERS substrates. Furthermore, even at an analyte concentration reduced to 10−9 m, a SERS characteristic peak intensity of approximately 2 × 103 is measurable, demonstrating the high sensitivity of the assembled structures. Finally, by detecting SERS signals from NCs of varying sizes, the intensities of characteristic peaks tend to converge, eliminating the influence of morphology and size on SERS detection. [ABSTRACT FROM AUTHOR]

An ultrasensitive method for the visual detection of microRNAs (miRNAs) in cell lysates using a gold nanorod-based lateral flow nucleic acid biosensor (GN-LFNAB) and exonuclease III (Exo III)-assisted signal amplification. The Exo III-catalyzed target recycling strategy is employed to generate a large number of single-strand DNA products, which can be detected by GN-LFNAB visually. With the implementation of a unique recycling strategy, we have demonstrated that the miRNA in the concentration as low as 0.5 pM can be detected without the need for instrumentation, providing a detection limit that surpasses previous reports. The new biosensor is ultrasensitive and can be applied to the reliable monitoring of miRNAs in cell lysates with high accuracy. The approach offers a simple and rapid tool for cancer diagnosis and clinical biomedicine, thanks to its flexibility, simplicity, cost-effectiveness, and convenience. This new method has the potential to significantly improve the detection and monitoring of cancer biomarkers, ultimately contributing to more effective cancer diagnosis and treatment. [ABSTRACT FROM AUTHOR]

Multidrug resistance (MDR) remains a formidable challenge in cancer treatment, necessitating innovative strategies to enhance therapeutic outcomes. This review explores the potential of a synergistic gold nanorod (GNR) therapy (SGNRT) utilizing GNRs as multifunctional platforms for co‐delivering chemotherapy and thermal therapies. The rational design of SGNRT systems enables targeted payload delivery, circumvention of Adenosine triphosphate (ATP)‐binding cassette drug efflux transporters, and hyperthermia‐induced chemo sensitization. In vitro studies demonstrate the synergistic impact of SGNRT in overcoming MDR, emphasizing its potential for enhanced antitumor efficacy. However, further in vivo investigations are essential to assess the clinical viability of this nanoparticle (NP)‐directed approach against advanced multidrug‐resistant malignancies. The integration of SGNRT holds promise for advancing precision cancer therapies and addressing the intricate challenges of drug resistance in clinical settings. [ABSTRACT FROM AUTHOR]

Measurement of anisotropy factor (g) in the presence of nanoparticles (NPs) is important for understanding light distribution for plasmonic photothermal cancer therapeutics. Here, anisotropy factor is investigated through bilayer phantoms (epidermal and dermal) of various thicknesses incorporated with gold nanorods (GNRs) concentrations of 10–40 μg/mL by using in‐house developed goniometric setup. Results show that 10 μg/mL GNRs in the phantom increase g by ~50% (g = 0.9471) w.r.t. phantom without NPs. Higher concentrations (40 μg/mL) of GNRs decrease g by ~43% (g = 0.5341) w.r.t. phantom with 10 μg/mL GNRs. For 40 μg/mL GNRs phantom, the anisotropy factor reduces by 47% for phantom thickness from 600 to 1800 μm. Anisotropy factor of GNR embedded phantom increased by 44% by using glycerol (10%–40%). Incorporation of NPs in a tumor significantly affects g, a major parameter for light distribution. These measurements provide insights for light scattering based on nanoparticle doses for plasmonic photothermal therapeutics. [ABSTRACT FROM AUTHOR]

Ascorbic acid (AA) is the most widely used reductant for noble metal nanoparticle (NP) synthesis. Despite the synthetic relevance, its aqueous chemistry remains misunderstood, due in part to various assumptions about its reduction pathway which are insufficiently supported by experimental evidence. This study aims to provide an understanding of the complex chemistry associated with AA under aqueous conditions. We demonstrate that (i) AA undergoes appreciable degradation in alkaline solution on a timescale relevant to NP synthesis, (ii) contrary to popular belief, AA does not degrade into dehydroascorbic acid (DHA), nor is DHA the oxidized product of AA under noble metal NP synthetic conditions, (iii) DHA, which readily degrades under alkaline conditions, can also effectively reduce metal salt precursors to metal NPs, (iv) neither ascorbate nor dehydroascorbate act as surface capping agents post‐synthetically on the NPs (v) AA degradation time greatly affects the morphology and polydispersity of the resultant NP. Results from our mechanistic investigation enabled us to utilize purposefully‐aged reductants to achieve control over shape yield and monodispersity in the seed‐mediated synthesis of Au nanorods. Our findings have important implications for achieving monodispersed products in the many metal NP synthesis reactions that make use of AA as a reducing agent. [ABSTRACT FROM AUTHOR]

Thermoresponsive hydrogels were 3D-printed with embedded gold nanorods (GNRs), which enable shape change through photothermal heating. GNRs were functionalized with bovine serum albumin and mixed with a photosensitizer and poly(N-isopropylacrylamide) (PNIPAAm) macromer, forming an ink for 3D printing by direct ink writing. A macromer-based approach was chosen to provide good microstructural homogeneity and optical transparency of the unloaded hydrogel in its swollen state. The ink was printed into an acetylated gelatin hydrogel support matrix to prevent the spreading of the low-viscosity ink and provide mechanical stability during printing and concurrent photocrosslinking. Acetylated gelatin hydrogel was introduced because it allows for melting and removal of the support structure below the transition temperature of the crosslinked PNIPAAm structure. Convective and photothermal heating were compared, which both triggered the phase transition of PNIPAAm and induced reversible shrinkage of the hydrogel–GNR composite for a range of GNR loadings. During reswelling after photothermal heating, some structures formed an internally buckled state, where minor mechanical agitation recovered the unbuckled structure. The BSA-GNRs did not leach out of the structure during multiple cycles of shrinkage and reswelling. This work demonstrates the promise of 3D-printed, photoresponsive structures as hydrogel actuators. [ABSTRACT FROM AUTHOR]

Achieving precise spatiotemporal control over the release of proangiogenic factors is crucial for vasculogenesis, the process of de novo blood vessel formation. Although various strategies have been explored, there is still a need to develop cell-laden biomaterials with finely controlled release of proangiogenic factors at specific locations and time points. We report on the developed of a near-infrared (NIR) light-responsive collagen hydrogel comprised of gold nanorods (GNRs)-conjugated liposomes containing proangiogenic growth factors (GFs). We demonstrated that this system enables on-demand dual delivery of GFs at specific sites and over selected time intervals. Liposomes were strategically formulated to encapsulate either platelet-derived growth factor (PDGF) or vascular endothelial growth factor (VEGF), each conjugated to gold nanorods (GNRs) with distinct geometries and surface plasmon resonances at 710 nm (GNR710) and 1064 nm (GNR1064), respectively. Using near infrared (NIR) irradiation and two-photon (2P) luminescence imaging, we successfully demonstrated the independent release of PDGF from GNR710 conjugated liposomes and VEGF from GNR1064-conjugated liposomes. Our imaging data revealed rapid release kinetics, with localized PDGF released in approximately 4 min and VEGF in just 1 and a half minutes following NIR laser irradiation. Importantly, we demonstrated that the release of each GF could be independently triggered using NIR irradiation with the other GF formulation remaining retained within the liposomes. This light-responsive collagen hydrogels holds promise for various applications in regenerative medicine where the establishment of a guided vascular network is essential for the survival and integration of engineered tissues. In this study, we have developed a light-responsive system with gold nanorods (GNRs)-conjugated liposomes in a collagen hydrogel, enabling precise dual delivery of proangiogenic growth factors (GFs) at specific locations and timepoints. Liposomes, containing platelet-derived growth factor (PDGF) or vascular endothelial growth factor (VEGF), release independently under near- infrared irradiation. This approach allows external activation of desired GF release, ensuring high cell viability. Each GF can be triggered independently, retaining the other within the liposomes. Beyond its application in establishing functional vascular networks, this dual delivery system holds promise as a universal platform for delivering various combinations of two or more GFs. [Display omitted] [ABSTRACT FROM AUTHOR]

A glassy carbon electrode (GCE) modified with electrochemically reduced graphene oxide (ErGO) and gold nanorods (AuNRs) (GCE/ErGO/AuNRs) was prepared for determining As(III) in bivalve mollusks samples (Mytilus chilensis). The modified electrode was characterized by cyclic voltammetry, scanning electron microscopy (SEM), and atomic force microscopy (AFM). Chemical and electrochemical parameters were optimized, observing that the presence of AuNRs provides selectivity, while the incorporation of ErGO improves the sensitivity of the modified electrode for the detection of As(III). Using square wave anodic stripping voltammetry (SWASV), a linear range of 2.0–60.0 µg L−1 with a detection limit (LOD) of 0.21 µg L−1 was obtained. The validation was made using water and mussel tissue-certified reference materials (TMDA-64.2 and ERM®-CE278k, respectively), showing good accuracy and reproducibility. The methodology allowed the determination of As(III) in real samples of marine resources, with excellent results (RSD < 2%). [ABSTRACT FROM AUTHOR]

Amino acid deprivation therapy (AADT) is a novel anticancer therapy, considered nontoxic and selective. Thermophilic L-asparaginase enzymes display high stability and activity at elevated temperatures. However, they are of limited use in clinical applications because of their low substrate affinity and reduced activity under physiological conditions, which may necessitate an improved dosage, leading to side effects and greater costs. Thus, in an attempt to improve the activity of L-Asn at 37 °C, with the use of a semi-rational design, eight active-site mutants of Thermococcus litoralis DSM 5473 L-asparaginase Tli10209 were developed. T70A exhibited a 5.11-fold increase compared with the wild enzyme in physiological conditions. Double-mutant enzymes were created by combining mutants with higher hydrolysis activity. T70A/F36Y, T70A/K48L, and T70A/D50G were enhanced by 5.59-, 6.38-, and 5.58-fold. The immobilized enzyme applied in MCF-7 breast cancer cells only required one-seventh of the dose of the free enzyme to achieve the same inhibition rate under near-infrared irradiation. This provides a proof of concept that it is possible to reduce the consumption of L-Asn by improving its activity, thus providing a method to manage side effects. [ABSTRACT FROM AUTHOR]

Gold nanomaterials have been widely explored in electrochemical sensors due to their high catalytic property and good stability in multi-medium. In this paper, the reproducibility of the signal among batches of gold nanorods (AuNRs)-modified electrodes was investigated to improve the data stabilization and repeatability. Ordered and random self-assembled AuNRs-modified electrodes were used as electrochemical sensors for the simultaneous determination of dopamine (DA) and topotecan (TPC), with the aim of obtaining an improved signal stability in batches of electrodes and realizing the simultaneous determination of both substances. The morphology and structure of the assemblies were analyzed and characterized by UV–Vis spectra, scanning electron microscopy (SEM), transmission electron microscopy (TEM), and X-ray powder diffraction (XRD). Electrochemical studies showed that the ordered AuNRs/ITO electrodes have excellent signal reproducibility among several individuals due to the homogeneous mass transfer in the ordered arrangement of the AuNRs. Under the optimized conditions, the simultaneous detection results of DA and TPC showed good linearity in the ranges 1.75–45 μM and 1.5–40 μM, and the detection limits of DA and TPC were 0.06 μM and 0.17 μM, respectively. The results showed that the prepared ordered AuNR/ITO electrode had high sensitivity, long-term stability, and reproducibility for the simultaneous determination of DA and TPC, and it was expected to be applicable for real sample testing. [ABSTRACT FROM AUTHOR]

In recent years, the use of gold nanorods (AuNRs) has garnered considerable attention in biomedical applications due to their unique optical and physicochemical properties. They have been considered as potential tools for the advanced treatment of diseases by various stimuli such as magnetic fields, pH, temperature and light in the fields of targeted therapy, imaging and drug delivery. Their biocompatibility and tunable plasmonic properties make them a versatile platform for a range of biomedical applications. While endogenous stimuli have limited cargo delivery control at specific sites, exogenous stimuli are a more favored approach despite their circumscribed penetration depth for releasing the cargo at the specific target. Dual/multi-stimuli responsive AuNTs can be triggered by multiple stimuli for enhanced control and specificity in biomedical applications. This review provides to provide a summary of the biomedical applications of stimuli-responsive AuNRs, including their endogenous and exogenous properties, as well as their dual/multi-functionality and potential for clinical delivery. This review provides a comprehensive review on the improvement of therapeutic efficacy and the effective control of drug release with AuNRs, highlights AuNRs design strategies in recent years, discusses the advantages or challenges so far in the field of AuNRs. Finally, we have addressed the clinical translation bio-integrated nanoassemblies (CTBNs) in this field.

The use of photothermal processes has been proven effective in the control of microbial infections. Simultaneously, the localized surface plasmon resonance phenomena in metallic nanoparticles have been explored as an alternative strategy to achieve highly efficient localized heating. In this work, we propose the use of selected nanoheaters to improve the efficiency of fungal photothermal inactivation of Candida albicans through size optimization of plasmonic gold nanorods. Here, the optical heating of polyethylene glycol coated gold nanorods of varying sizes is evaluated, both theoretically and experimentally. A size-dependent computational approach was applied to identify metallic nanorods with maximized thermal performance at 800 nm, followed by the experimental comparison of optimal and suboptimal nanoheaters. Comparison among samples show temperatures of up to 53.0 °C for 41×10 nm gold nanorods against 32.3 °C for 90×25 nm, a percentage increase of ∼63% in photothermal inactivation assessments. Our findings reveal that gold nanorods of 41×10 nm exhibit superior efficiency in near-infrared (800 nm) photothermal inactivation of fungi, owing to their higher light-thermal conversion efficiency. The identification of high performance metallic nanoheaters may lead to the reduction of the nanoparticle dose used in plasmonic-based procedures and decrease the laser exposure time needed to induce cell death. Moreover, our results provide insights to better exploit plasmonic nanoparticles on photothermal inactivation protocols.

Abstract Chemotherapy treatment outcomes are severely restricted by multidrug resistance (MDR), in which tumors develop a multiple cross‐resistance toward drug involving the pump and nonpump resistance mechanisms, resulting in drug efflux and defending against drug toxicity. Herein, we constructed a pH and near infrared (NIR) light responsive nanomedicine DOX@FG based on gold nanorods (GNRs) that demonstrated the potential to improve chemotherapy outcomes by overcoming MDR. DOX@FG was constructed by conjugating folic acid (FA) and doxorubicin (DOX) derivatives onto GNRs, where the DOX derivatives possessed an acid‐labile hydrazone bond. Stimulated by the acidic media in endocytic organelles, DOX@FG exhibited a responsive dissociation for the controlled release of chemotherapeutic DOX. Surprisingly, we found the mild photothermal effect elicited by GNRs under NIR irradiation simultaneously inhibited the pump and nonpump resistance mechanisms, enhancing the intracellular DOX accumulation and sensitizing the cancer cells to DOX, collectively amplify the chemotherapy efficacy and delay the MCF‐7/ADR breast tumor growth. This intelligent DOX@FG nanomedicine with the potential for two‐pronged reversal of MDR may provide a prospective way to encourage chemotherapy efficacy.

As the most aggressive and metastatic subtype of breast cancer, clinical demands of triple negative breast cancer (TNBC) have far not been met. Heat shock protein 60 (HSP60) is over expressed in tumor cells and impair the efficacy of photothermal therapy. In this work, a conjugate composed of self-designed peptide targeting HSP60 and gold nanorods was constructed, referred to as AuNR-P17. Results showed that AuNR-P17 was able to simultaneously down regulate the level of HSP60 and locate in the mitochondria where HSP60 is enriched in the tumor cells of TNBC, which also impeded the interaction between HSP60 and integrin α3, thereby reducing the tumor cells' heat tolerance and metastatic capabilities. At the same time, AuNR-P17 induced remarkable mitochondrial apoptosis when exposed to the laser irradiation of 808 nm. The dual functions of AuNR-P17 led to the decrement of BCL-2 and the activation of p53 and cleaved caspase-3. The danger associated molecular patterns (DAMPs) generated from the mitochondrial apoptosis elicited strong and long-term specific immune responses against TNBC in vivo and ultimately inhibited the tumor metastasis and recurrence with significantly prolonged survival (>100 days) on TNBC mice. In conclusion, this study demonstrated HSP60 a promising potential therapeutic target for triple negative breast cancer and exhibited powerful capacity of AuNR-P17 in photothermal immune therapy.

Bone metastasis remains a clinical challenge and is still considered incurable. While nanoparticles-based drug delivery and photothermal therapy (PTT) show promise in treating subcutaneous solid tumor, their therapeutic outcome in treating bone metastasis is limited, due to the inaccessibility of bone metastatic site and the complexity of bone metastasis. Herein, we reported a simple nanoplatform composed of thermo-sensitive liposomes (TSL) and gold nanorods (GNR) to treat bone metastasis through improved chemotherapy combined with GNR-assisted PTT. Lipid combination of TSL was firstly tailored to regulate its stability under physiological condition as well as its sensitivity in responding to PTT-caused mild hyperthermia. The obtained TSL with loaded drug was then combined with GNR to form the nanoplatform through unsophisticated incubation. Cell experiments revealed that upon near-infrared (NIR) irradiation, the nanoplatform effectively inhibited the viability and migration ability of tumor cells through PTT, PTT-triggered thermo-sensitive drug release, and PTT-augmented sensitivity of tumor cells to drug. In a murine model of bone metastasis, the nanoplatform enabled effective delivery of loaded drug and GNR to bone metastatic site for rapid drug release upon local NIR irradiation. Through killing tumor cells and rebalancing the turnover of osteoclasts and osteoblasts, the nanoplatform largely preserved bone structure for pain relief and survival extension. Inspired by the simplicity of nanoplatform acquirement and treatment operation, the strategy of liposomes-based thermo-sensitive drug delivery in combination with GNR-assisted PTT is considered greatly promising in treating bone metastasis.

Protein-based biomaterials such as thin films have an edge over synthetic and bio-based polymers, due to their biodegradability in addition to other interesting properties. Proteins can be utilized to create such materials with specific functional characteristics. We report the preparation of transparent human serum albumin thin films in presence of CTAB-capped gold nanorods with different compositions of protein as well as the plasticizer i.e., sorbitol. The mechanical properties, surface topology, morphology, molecular structure, moisture content, total soluble material, biodegradability, antibacterial activity and optical properties have been investigated. Gold nanorods act as crosslinkers and sorbitol as a plasticizer increases plasticity and hardness of the films. The films deposited are biodegradable, water soluble and flexible in nature. AFM images reveal a pattern on the surface with different average heights with an increase in surface roughness with the addition of sorbitol. NINT studies show increased hardness and elastic modulus with the same amount of sorbitol but higher amounts of protein. Fourier Transform Infrared spectroscopy studies indicate the change in molecular structure of the films, in terms of a change in the hydrogen bonding network that impacts the water content and hardness of the films. Most importantly the films show antibacterial property, modulated by the composition used. The interesting features and the enhanced mechanical properties pave the path for potential applications of the films. The study shows that the optimization of the composition is crucial to achieve the desired film material with required properties.

AbstractMicroRNAs (miRNAs) are endogenous, noncoding, and sequence-specific single-stranded RNA regulatory factors whose abnormal expression levels are closely related to various diseases, especially cancer, and are considered effective biomarkers for disease diagnosis and prognosis. Since the concentrations of miRNAs in the body are low and disease diagnosis by detecting single miRNAs may result in a high false positive, it is essential to construct a sensitive biosensor for the determination of multiple miRNAs. In this work, an enzyme-free signal amplification assay based on plasma-enhanced fluorescence (PEF) is reported for the one-step simultaneous determination of two miRNAs. Gold nanorods (AuNRs) were functionalized with fluorescein isothiocyanate (FAM)-tagged hairpin DNA1 (H1) and cyanine 5.5 (Cy5.5)-tagged hairpin DNA2 (H2). The fluorescence signals of FAM and Cy5.5 were quenched due to their proximity to the surface of the AuNRs. In the presence of target miRNA-21 and miRNA-155, H1 and H2 complemented miRNA-21 and miRNA-155, respectively, and the fluorescence signals of FAM and Cy5.5 were not only restored but amplified due to the plasma-enhanced fluorescence. A suitable linear range (0.1 to 10 nM) and low limits of detection for miRNA-21 (23 pM) and miRNA-155 (1.6 pM) were achieved. The developed assay for the one-step simultaneous measurement of two miRNAs is simple, fast and sensitive, exhibiting great potential for monitoring these biomarkers. [ABSTRACT FROM AUTHOR]

Among various hybrid nanomaterials, the combination of plasmonic nanoparticles and fluorophores in a single multifunctional nanoplatform, so‐called plasmophores, has attracted significant attention in different fields such as dark field, fluorescence, and photoacoustic imaging, biosensing, photothermal, and photodynamic therapy. Herein, author report a facile and controlled synthesis route of hybrid nanoplatforms composed of fluorescent gold nanoclusters (GNCs) coupled to plasmonic gold nanorods (GNRs) using controlled silica (SiO2) dielectric spacers of different thicknesses from now on referred to as GNR@SiO2@GNC plasmophores. The results show different degrees of plasmon‐enhanced fluorescence of the GNCs in their plasmophore hybrid system when placed at different distances from the plasmonic cores of the GNRs. On the other hand, these plasmophores show enhanced thermal stability compared to GNRs@CTAB (CTAB, cetyl trimethyl ammonium bromide). This results also demonstrated that upon annealing at elevated temperatures (800–1000 °C), the GNRs in the plasmophores are more thermally stable and robust than the GNRs@CTAB. More surprisingly, despite the commonly reported very low melting temperature of smaller‐size nanocrystals, the GNCs in the plasmophores showed high thermal stability and do not exhibit significant structural changes at elevated temperatures (800–1000 °C). [ABSTRACT FROM AUTHOR]

Photothermal therapy (PTT) is recognized as an effective tool for the treatment of cancer and it has attracted considerable attention of scientists. In this work, gold nanospheres (AuNSs) and gold nanorods (AuNRs) stabilized using poly(N‐vinylpyrrolidone) (PVP), pristine gellan gum (PGG), and poly(2‐ethyl‐2‐oxazoline)‐grafted gellan gum (GG‐g‐PEtOx) are synthesized and evaluated as PTT agents in Ehrlich cancer cells. The physicochemical characteristics of these AuNSs and AuNRs, including their surface plasmon resonance absorption spectra, size, zeta potential, and aspect ratio are studied using UV–vis‐spectroscopy, dynamic light scattering, zeta potential, transmission electron microscopy, and optical microscopy techniques. The polymer‐protected AuNSs exhibit light‐to‐heat conversion, raising the temperature from 37 to 43 °C when irradiated using a visible light source. In the case of AuNSs, considerable damage to Ehrlich cancer cells is observed following irradiation and 40 days of examination. However, with regard to AuNSs, the damage to Ehrlich cancer cells is slightly lower than observed in AuNRs. In vivo experiments demonstrate that laser irradiation of tumors in mice after injecting AuNSs leads to a statistically significant decrease in tumor size as compared to those not irradiated and the control samples. [ABSTRACT FROM AUTHOR]

Photothermal therapy and immunotherapy are emerging strategies for treating tumors. The combination of these two therapies can effectively leverage their advantages, thereby enhancing the therapeutic efficacy. Based on this premise, the natural polysaccharide was prepared from the edible Rosa roxburghii fruit and applied to coat gold nanorods (GNRs). The antitumor nanorods, designated as RRP-MPBA-GNRs, were developed to combine photothermal therapy and immunotherapy. This system employed 4-mercaptophenylboronic acid (MPBA) as the connecting unit. The hydroxy groups of RRP formed dynamic borate ester bonds with MPBA, and this conjugated bonds exhibited pH-responsive properties. The RRP-MPBA was immobilized on the surface of GNRs through sulfur–gold bonds, enhancing the stability and preserving the photothermal effects of GNRs. In vivo experiments have demonstrated that RRP-MPBA-GNRs reduced the number of cancer cells at the transplant site and inhibited metastasis. Further investigation revealed that the photothermal effects of RRP-MPBA-GNRs can increase reactive oxygen species (ROS) levels in cancer cells and induce apoptosis. RRP released from RRP-MPBA-GNRs can induce an antitumor immune response by promoting the maturation of dendritic cells and up-regulating the expression of surface marker molecules. The results suggested that RRP-MPBA-GNRs can effectively integrate photothermal therapy and immunotherapy for tumor treatment. [ABSTRACT FROM AUTHOR]

Despite the use of silver in various industries, this heavy metal can pose serious risks to living organisms and the environment. Therefore, the development of simple measurement strategies for detection of silver ions (Ag+) with high sensitivity is of great importance. In this research, gold nanorods (AuNRs) have been used as indicator element in colorimetric sensor, which provides the possibility of facile and visual detection of silver by forming gold@silver core‐shell nanostructures (Au@Ag NRs). The basis of this sensor is the metallization of silver on AuNRs through ascorbic acid (AA) as a reducing agent, which forms Au@Ag NRs. During this mechanism, Ag+ is converted to silver atom (Ago) in the presence of AA and the surface of AuNRs is coated by inducing metallization. Any changes in composition and dimensions of AuNRs will cause color changes in the detection solution and subsequently spectral changes. The obtained results showed a good correlation between silver concentration and probe response (λo–λ) in the range of 2.5 to 30.0 μmol L−1 with a detection limit of 1.3 μmol L−1. In addition, the evaluation of the sensor in water and soil samples showed that it has acceptable accuracy in detecting silver ions in real conditions. [ABSTRACT FROM AUTHOR]

This work reports on the design, development, and characterization of novel magneto-plasmonic elastic liposomes (MPELs) of DPPC:SP80 (85:15) containing Mg0.75Ca0.25Fe2O4 nanoparticles coupled with gold nanorods, for topical application of photothermal therapy (PTT). Both magnetic and plasmonic components were characterized regarding their structural, morphological, magnetic and photothermal properties. The magnetic nanoparticles display a cubic shape and a size (major axis) of 37 ± 3 nm, while the longitudinal and transverse sizes of the nanorods are 46 ± 7 nm and 12 ± 1.6 nm, respectively. A new methodology was employed to couple the magnetic and plasmonic nanostructures, using cysteine as bridge. The potential for photothermia was evaluated for the magnetic nanoparticles, gold nanorods and the coupled magnetic/plasmonic nanoparticles, which demonstrated a maximum temperature variation of 28.9 °C, 33.6 °C and 37.2 °C, respectively, during a 30 min NIR-laser irradiation of 1 mg/mL dispersions. Using fluorescence anisotropy studies, a phase transition temperature (Tm) of 35 °C was estimated for MPELs, which ensures an enhanced fluidity crucial for effective crossing of the skin layers. The photothermal potential of this novel nanostructure corresponds to a specific absorption rate (SAR) of 616.9 W/g and a maximum temperature increase of 33.5 °C. These findings point to the development of thermoelastic nanocarriers with suitable features to act as photothermal hyperthermia agents. [ABSTRACT FROM AUTHOR]

Significance: Assessing the nanostructure of polymer solutions and biofluids is broadly useful for understanding drug delivery and disease progression and for monitoring therapy. Aim: Our objective is to quantify bronchial mucus solids concentration (wt. %) during hypertonic saline (HTS) treatment in vitro via nanostructurally constrained diffusion of gold nanorods (GNRs) monitored by polarization-sensitive optical coherence tomography (PS-OCT). Approach: Using PS-OCT, we quantified GNR translational (DT) and rotational (DR) diffusion coefficients within polyethylene oxide solutions (0 to 3 wt. %) and human bronchial epithelial cell (hBEC) mucus (0 to 6.4 wt. %). Interpolation of DT and DR data is used to develop an assay to quantify mucus concentration. The assay is demonstrated on the mucus layer of an air–liquid interface hBEC culture during HTS treatment. Results: In polymer solutions and mucus, DT and DR monotonically decrease with increasing concentration. DR is more sensitive than DT to changes above 1.5 wt. % of mucus and exhibits less intrasample variability. Mucus on HTS-treated hBEC cultures exhibits dynamic mixing from cilia. A region of hard-packed mucus is revealed by DR measurements. Conclusions: The extended dynamic range afforded by simultaneous measurement of DT and DR of GNRs using PS-OCT enables resolving concentration of the bronchial mucus layer over a range from healthy to disease in depth and time during HTS treatment in vitro. [ABSTRACT FROM AUTHOR]

A three‐dimensional (3D) plasmonic substrate was developed using gold nanorods (GNRs) onto a tapered fiber surface using optical tweezing. To determine the efficacy of the substrate, Raman spectra of two toxic chemicals Rhodamine 6G (R6G) and Crystal Violet (CV) were studied. The "dip and dry" method was used to adsorb the chemicals along the tapered fiber length. The minimum concentration detected for CV and R6G was 10−12 M. We have reported the characteristics and unique features of the manufactured substrate. [ABSTRACT FROM AUTHOR]

Cell-free synthesis technology is emerging as a versatile platform for biomanufacturing, particularly for on-site production of essential products. In this study, we address a pivotal challenge encountered when utilizing cell-free protein synthesis (CFPS) for on-site production in resource-limited settings. The efficacy of CFPS critically depends on precise temperature regulation. However, traditional heating methods are impractical for application outside of laboratory environments. To address this challenge, we propose an innovative solution that integrates gold nanorods (GNRs) with photothermal properties into the CFPS reaction mixture. Upon activation by a handheld laser module emitting near-infrared light, these GNRs efficiently convert light energy into heat, enabling rapid and precise temperature control for protein synthesis. Our approach not only achieves optimal synthesis temperatures more rapidly than conventional methods but also significantly enhances protein yields, with an increase of over threefold within a 30-min reaction period. In summary, our findings highlight the potential of photothermal heating as a means to ensure portable and efficient protein synthesis in the field. This advancement brings CFPS closer to achieving real-time, on-site protein production. [ABSTRACT FROM AUTHOR]

We studied grafted tumors obtained by subcutaneous implantation of kidney cancer cells into male white rats. Gold nanorods with a plasmon resonance of about 800 nm were injected intratumorally for photothermal heating. Experimental irradiation of tumors was carried out percutaneously using a near‐infrared diode laser. Changes in the optical properties of the studied tissues in the spectral range 350–2200 nm under plasmonic photothermal therapy (PPT) were studied. Analysis of the observed changes in the absorption bands of water and hemoglobin made it possible to estimate the depth of thermal damage to the tumor. A significant decrease in absorption peaks was observed in the spectrum of the upper peripheral part and especially the tumor capsule. The obtained changes in the optical properties of tissues under laser irradiation can be used to optimize laboratory and clinical PPT procedures. [ABSTRACT FROM AUTHOR]

Colloidal gold nanorods (GNRs) have demonstrated their potential to absorb light within specific wavelength bands and induce photothermal effects. However, the unpredictability and lack of adjustability in the broadband spectrum formed by the self-assembly of gold nanospheres or the coupling of various sizes of GNRs have posed significant challenges. To address this, we have developed broadband GNRs (BGNRs) with a predictable and adjustable extinction band in the visible and near-infrared regions. The BGNRs were synthesized by simply mixing GNRs with different aspect ratios, allowing for control over the bandwidths and positions of the extinction bands. Subsequently, the BGNRs were coated with silica and underwent surface modification. The resulting BGNRs@SiO2 were then mixed with either polydimethylsiloxane (PDMS) or polyvinylidene fluoride (PVDF) to create BGNRs@SiO2/PDMS (or PVDF) films. The BGNRs@SiO2/PDMS and BGNRs@SiO2/PVDF films both exhibit excellent photothermal performance properties. Additionally, the light absorption intensity of the BGNRs@SiO2/PVDF film linearly increases upon folding, leading to significantly enhanced photothermal performance after folding. This work demonstrates that plasmonic colloidal GNRs, without the need for coupling, can yield predictable and adjustable extinction bands. This finding holds great promise for future development and practical applications, particularly in the transfer of these properties to films. [ABSTRACT FROM AUTHOR]

We developed a fluorescent molecular probe based on gold nanoparticles functionalized with N,N′-bis(2-(1-piperazino)ethyl)-3,4,9,10-perylenetetracarboxylic acid diimide dihydrochloride, and these probes exhibit potential for applications in microscopic thermometry. The intensity of fluorescence was affected by changes in temperature. Chemical environments, such as different buffers with the same pH, also resulted in different fluorescence intensities. Due to the fluorescence intensity changes exhibited by modified gold nanoparticles, these materials are promising candidates for future technologies involving microscopic temperature measurements. [ABSTRACT FROM AUTHOR]

MicroRNA (miRNA) modulation has been identified as a promising strategy for improving the response of human prostate cancer (PCa) to radiotherapy (RT). Studies have shown that mimics or inhibitors of miRNAs could modulate the sensitivity of PCa cells to RT. In addition, pegylated gold nanoparticles have been studied as a therapeutic approach to treat PCa cells and/or vehicles for carrying miRNAs to the inside of cells. Therefore, we evaluated the capacity of hypofractionated RT and pegylated gold nanorods (AuNPr-PEG) to modulate the miRNA signature on PCa cells. Thus, RT-qPCR was used to analyze miRNA-95, miRNA-106-5p, miRNA-145-5p, and miRNA-541-3p on three human metastatic prostate cell lines (PC3, DU145, and LNCaP) and one human prostate epithelial cell line (HprEpiC, a non-tumor cell line) with and without treatment. Our results showed that miRNA expression levels depend on cell type and the treatment combination applied using RT and AuNPr-PEG. In addition, cells pre-treated with AuNPr-PEG and submitted to 2.5 Gy per day for 3 days decreased the expression levels of miRNA-95, miRNA-106, miRNA-145, and miRNA-541-3p. In conclusion, PCa patients submitted to hypofractionated RT could receive personalized treatment based on their metastatic cellular miRNA signature, and AuNPr-PEG could be used to increase metastatic cell radiosensitivity. [ABSTRACT FROM AUTHOR]

Abstract Gold nanorods (AuNRs), 1D rod‐shaped nanomaterials, hold a crucial role in sensing applications due to their distinct physicochemical properties, such as high surface area, efficient mass transfer, good biocompatibility, and anisotropic optical and electronic responses. This review outlines the most recent advancements in AuNRs research, offering a comprehensive summary of synthetic strategies. Subsequently, the potential of AuNRs in sensor applications is discussed, and for the first time, an innovative analysis of their application in the sensor field based on the aspect ratio of AuNRs is proposed. These sensing systems are utilized for detecting heavy metal ions, inorganic anions, small biomolecules, protein tumor markers, enzymes, and nucleic acids. Finally, the future research directions and challenges of AuNRs are addressed.

Polymeric microneedles (PMNs) are an attractive transdermal drug delivery approach with minimal invasiveness and improved patient compliance. However, it is uncomfortable and inconvenient for patients to wear a PMN patch for hours or days until complete payload release. Here, we report a facile strategy to fabricate rapidly separable PMN arrays activated by near-infrared (NIR) light (NIR-RS-PMN) with enhanced mechanical strength through introduction of a photothermal-sensitive spacer integrating plasmonic gold nanorods into a biocompatible sodium hyaluronate matrix. Under NIR irradiation, the NIR-RS-PMN achieved rapid separation of the patch backing and microneedles within 1 min. The loaded bioactive therapeutics, e.g., insulin and RNA, were well-preserved during fabrication, NIR irradiation, and 20-day storage at room temperature. The NIR-RS-PMN was well tolerated by rats without skin irritation. Its feasibility for biologics delivery was further established by the treatment of diabetic rats with insulin encapsulated PMNs. The innovative PMNs increase ease of use and achieve effective and precise payload delivery, which may increase access to biopharmaceuticals and vaccines in remote and resource-limited communities.