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With the continuous advancement of nanotechnology, the application of gold nanorods (AuNRs) functionalized with polysaccharides in the realm of cancer photothermal therapy is garnering increasing attention. To harness photothermal therapy for cancer treatment, FLP-MPBA-AuNRs were successfully synthesized in this study for the first time, utilizing Poria cocos polysaccharides (FLP), mercaptophenylboronic acid (MPBA), and gold nanorods (AuNRs). FLP-MPBA-AuNRs are a nanomaterial characterized by a unique rod-shaped structure, featuring a long diameter of 29.3 nm and a short diameter of 6.5 nm, which conferred exceptional photothermal stability and remarkable photothermal conversion efficiency. Under near-infrared light irradiation, FLP-MPBA-AuNRs elicited significant photothermal effects, effectively curtailing the proliferation of various cancer cells. Additionally, FLP-MPBA-AuNRs impeded cancer progression by inducing cell apoptosis and releasing reactive oxygen species (ROS). Furthermore, FLP-MPBA-AuNRs suppressed the metastasis and growth of cancer cells in zebrafish models. In summary, FLP-MPBA-AuNRs showcased immense potential in cancer therapy by inhibiting tumor cell growth through photothermal and photodynamic mechanisms., Competing Interests: Declaration of competing interest The authors have no conflicts of interest., (Copyright © 2024 Elsevier B.V. All rights reserved.)

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., Competing Interests: The authors declare that they have no known competing financial interests., (© 2024 The Authors.)

Liquid crystalline elastomers (LCEs) are stimuli-responsive materials that transduce an input energy into a mechanical response. LCE composites prepared with photothermal agents, such as nanoinclusions, are a means to realize wireless, remote, and local control of deformation with light. Amongst photothermal agents, gold nanorods (AuNRs) are highly efficient converters when the irradiation wavelength matches the longitudinal surface plasmon resonance (LSPR) of the AuNRs. However, AuNR aggregation broadens the LSPR which also reduces photothermal efficiency. Here, the surface chemistry of AuNRs is engineered via a well-controlled two-step ligand exchange with a monofunctional poly(ethylene glycol) (PEG) thiol that greatly improves the dispersion of AuNRs in LCEs. Accordingly, LCE-AuNR nanocomposites with very low PEG-AuNR content (0.01 wt%) prepared by 3D printing are shown to be highly efficient photothermal actuators with rapid response (>60% strain s -1 ) upon irradiation with near-infrared (NIR; 808 nm) light. Because of the excellent dispersion of PEG-AuNR within the LCE, unabsorbed NIR light transmits through the nanocomposites and can actuate a series of samples. Further, the dispersion also allows for the optical deformation of millimeter-thick 3D printed structures without sacrificing actuation speed. The realization of well-dispersed nanoinclusions to maximize the stimulus-response of LCEs can benefit functional implementation in soft robotics or medical devices., (© 2024 Wiley‐VCH GmbH.)

Gold nanorods (AuNRs) have attracted significant attention over the past several decades for a variety of applications and there has been steady progress with regards to their synthesis and modification. Despite these advances, the assembly of AuNRs into well-organized hierarchical assemblies remains a formidable challenge. Specifically, there is a need for tools that can fabricate assemblies of nanorods over large length scales at low cost with the potential for high-throughput manufacturing. Langmuir-Blodgettry is a monolayer deposition technique which has been primarily applied to amphiphilic molecules, but which has recently shown promise for the ordering of functionalized nanoparticles residing at the air-water interface. In this work, Langmuir-Blodgett deposition is explored for the formation of AuNR arrays for enhanced surface-enhanced Raman spectroscopy (SERS) sensing. In particular, both surface modification of the AuNRs as well as subphase modification with cysteamine were evaluated for AuNR array fabrication., (© 2024 The Authors. ChemPhysChem published by Wiley-VCH GmbH.)

Abstract Background The exploitation of novel nanomaterials combining diagnostic and therapeutic functionalities within one single nanoplatform is challenging for tumor theranostics. Methods We synthesized dendrimer-modified gold nanorods for combinational gene therapy and photothermal therapy (PTT) of colon cancer. Poly(amidoamine) dendrimers (PAMAM, G3) grafted gold nanorods were modified with GX1 peptide (a cyclic 7-mer peptide, CGNSNPKSC). The obtained Au NR@PAMAM-GX1 are proposed as a gene delivery vector to gene (FAM172A, regulates the proliferation and apoptosis of colon cancer cells) for the combination of photothermal therapy (PTT) and gene therapy of Colon cancer cells (HCT-8 cells). In addition, the CT imaging function of Au NR can provide imaging evidence for the diagnosis of colon cancer. Results The results display that Au NR@PAMAM-GX1 can specifically deliver FAM172A to cancer cells with excellent transfection efficiency. The HCT-8 cells treated with the Au NR@PAMAM-GX1/FAM172A under laser irradiation have a viability of 20.45%, which is much lower than the survival rate of other single-mode PTT treatment or single-mode gene therapy. Furthermore, animal experiment results confirm that Au NR@PAMAM-GX1/FAM172A complexes can achieve tumor thermal imaging, targeted CT imaging, PTT and gene therapy after tail vein injection. Conclusion Our findings demonstrate that the synthesized Au NR@PAMAM-GX1 offer a facile platform to exert antitumor and improve the diagnostic level of tumor.

Abstract To combat the rise of antibiotic resistant bacteria, it is essential to look upon other therapeutic solutions that do not solely depend upon conventional antibiotics. Here, we have designed a combinational therapeutic approach that kills bacteria with the conjunction of photothermal (PT) and antibiotic therapy. A near‐infrared (NIR) laser activated targeted drug delivery nano‐assembly delivers antibiotic as well as offer PT therapy (PTT). The synergistic application of both therapies increases the efficacy of treatment. The protected delivery of antibiotic and its release in the proximity of the bacteria surface reduces off‐target toxicity and reduce the efficacious dosage. Core of the nano‐assembly is composed of NIR active gold nanorods (GNRs) coated with a mesoporous silica nanoparticle (MSNP), which serves as a carrier for an anti‐tuberculosis drug bedaquiline (BDQ). The assembly was wrapped within a thermo‐sensitive liposome (TSL) conjugated to mycobacteria‐targeting peptide: NZX, GNR@MSNP@BDQ@TSL@NZX. NZX mediates adhesion of final nano‐assembly on mycobacteria surface. Upon NIR laser irradiation GNRs convert photo energy of the laser to localized heat, which melts TSL triggering release of BDQ. Antibacterial activity of final nano‐assembly against Mycobacterium smegmatis (Msmeg) was 20 folds more efficacious than the free drug equivalent. The final nano‐assembly could also successfully inhibit the growth of intracellular mycobacteria residing in lung cells.

Osteosarcoma is a malignant bone tumor, which often occurs in adolescents. However, surgical resection usually fails to completely remove the tumor clinically, which has been the main cause of postoperative recurrence and metastasis, resulting in the high death rate of patients. At the same time, osteosarcoma invades a large area of the bone defect, which cannot be self-repaired and seriously affects the life quality of the patients. Herein, a bifunctional methacrylated gelatin/methacrylated chondroitin sulfate hydrogel hybrid gold nanorods (GNRs) and nanohydroxyapatite (nHA), which possessed excellent photothermal effect, was constructed to eradicate residual tumor after surgery and bone regeneration. In vitro, K7M2wt cells (a mouse bone tumor cell line) can be efficiently eradicated by photothermal therapy of the hybrid hydrogel. Meanwhile, the hydrogel mimics the extracellular matrix to promote proliferation and osteogenic differentiation of mesenchymal stem cells. The GNRs/nHA hybrid hydrogel was capable of photothermal treatment of postoperative tumors and bone defect repair in a mice model of tibia osteosarcoma. Therefore, the hybrid hydrogel possesses dual functions of tumor therapy and bone regeneration, which shows great potential in curing bone tumors and provides a new hope for tumor-related bone complex disease.

Due to their well-defined plasmonic properties, gold nanorods (GNRs) can be fabricated with optimal light absorption in the near-infrared region of the electromagnetic spectrum, which make them suitable for cancer-related theranostic applications. However, their controversial safety profile, as a result of surfactant stabilization during synthesis, limits their clinical translation. We report a facile method to improve GNR biocompatibility through the presence of sodium dodecyl sulfate (SDS). GNRs (120 × 40 nm) were synthesized through a seed-mediated approach, using cetyltrimethylammonium bromide (CTAB) as a cationic surfactant to direct the growth of nanorods and stabilize the particles. Post-synthesis, SDS was used as an exchange ligand to modify the net surface charge of the particles from positive to negative while maintaining rod stability in an aqueous environment. GNR cytotoxic effects, as well as the mechanisms of their cellular uptake, were examined in two different cancer cell lines, Lewis lung carcinoma (LLC) and HeLa cells. We not only found a significant dose-dependent effect of GNR treatment on cell viability but also a time-dependent effect of GNR surfactant charge on cytotoxicity over the two cell lines. Our results promote a better understanding of how we can mediate the undesired consequences of GNR synthesis byproducts when exposed to a living organism, which so far has limited GNR use in cancer theranostics.

We designed novel biocompatible nanocomposite composed of gold nanorods coated with rod-like mesoporous silica SBA-15-SH particles, (GNRs@SBA-15-SH) as a new synergistic therapeutic device to deliver heat and drug to cancer cells for tumor eradication. For this purpose, doxorubicin (DOX) was loaded into GNRs@SBA-15-SH nanocomposites and studied their photothermal therapy, chemotherapy and the combined effect on the ablation of A549 cells in vitro using human lung cancer cells, A549. The results demonstrate the high photothermal efficacy of gold nanorods loaded into the nanocomposite, the thermo-responsive properties of GNRs@SBA-15-SH, the high loading capacity of DOX into the GNRs@SBA-15-SH and its biocompatibility. Synergistic chemo-photothermal of the GNRs@SBA-15-SH/DOX nanocomposite in the eradication of cancer cells under laser irradiation (808 nm), demonstrates the high potential of therapeutic efficacy of this combined therapy over monotherapies.

Yu Lu,1,2 Zidong Peng,1,2 Di Zhu,1,2 Yijiang Jia,1,2 Ayijiang Taledaohan,1,2 Yuanming Li,3 Jiawang Liu,4 Yanming Wang,5 Yuji Wang1,2 1Department of Medicinal Chemistry, College of Pharmaceutical Sciences of Capital Medical University, Beijing, 100069, People’s Republic of China; 2Beijing Area Major Laboratory of Peptide and Small Molecular Drugs, Engineering Research Center of Endogenous Prophylactic of Ministry of Education of China, Beijing Laboratory of Biomedical Materials, Beijing Laboratory of Oral Health, Beijing, 100069, People’s Republic of China; 3Invasive Tumor Therapies Center, Beijing Hospital, National Center of Gerontology, Beijing, 100730, People’s Republic of China; 4Medicinal Chemistry Core, The University of Tennessee Health Science Center, 579 College of Pharmacy Building, Memphis, TN, 38163, USA; 5School of Life Sciences, Henan University, Kaifeng, 475004, People’s Republic of ChinaCorrespondence: Yuji Wang 10 Xi Tou Tiao, You An Men, Beijing, 100069, People’s Republic of ChinaTel +86-10-8391-1530Fax +86-10-8391-1533Email wangyuji@ccmu.edu.cnPurpose: A targeted drug delivery system that combines protein-arginine deiminase type-4 (PAD4) inhibitors YW3-56 (356) with PTT of NPs is constructed to both decrease the accumulation of gold in metabolic organs and reduce the dose of chemotherapeutic agents.Patients and Methods: In vitro cytotoxicity test and in vivo S180 tumor-bearing mice model were used to compare antitumor activity of 356-modified gold nanospheres and nanorods. The A549 tumor-bearing mice model was also exploited in antitumor assessment. In addition, ICP-MS, blood cell analyzer and blood biochemistry analyzer are applied for assessing the biosafety of NPs.Results: Both 356-modified gold nanospheres and nanorods showed antitumor activity. However, 356-loaded gold nanorods are found to have better tumor inhibitory activity than 356-loaded gold nanospheres in the presence of laser and without laser irradiation. Thus, 356-loaded gold nanorods are selected to be applied for chemo-photothermal combined therapy on in vivo. We find that combination therapy could inhibit tumor growth and reduce lung tumor metastasis and inflammatory infiltration compared with individual therapy. It triggers apoptosis in tumor tissue observed by TUNEL assay and TEM pictures.Conclusion: Thus, an RGD targeting and PAD4 inhibitor-loaded system are established based on chemo-photothermal combined therapy. It could inhibit tumor growth, prevent lung metastasis and improve biosafety.Keywords: gold nanospheres, gold nanorods, PAD4 inhibitor, chemo-photothermal combined therapy, biosafety

The nanoparticle surfaces interact readily with biomolecules, including proteins forming a corona. The protein layer that directly interacts with the nanoparticle surface is usually explored. Non-covalent interactions of proteins in the second layer have not been elucidated. We report for the first-time multilayer protein-protein interactions in ubiquitin corona on gold nanorod surface. The conformational dynamics of the protein, ubiquitin, on the surface of gold nanorods were probed at the molecular level using two-dimensional solution nuclear magnetic resonance spectroscopy. The interaction of Ubiquitin with gold nanorods was characterized by UV–visible spectroscopy, dynamic light scattering, and zeta-potential measurements. The residues of Ubiquitin that show significant perturbations fall into two categories: (a) the residues that directly interact with the surface of gold nanorods forming hard corona (primary interaction) and (b) the residues that are forming soft corona (secondary interaction). The formation of hard corona on the surface of the nanorod takes place even at a low concentration of the protein. The protein does not undergo any changes in its secondary or tertiary structure. As the protein concentration is increased, the hard corona, which is off mutually interconvertible multiple conformers, undergoes conformational reorientation to maximize its interaction with the nanorod surface. The study reveals electrostatically driven weak protein-nanorod interactions. Further, the study reveals two different processes, one involving the direct interaction with nanorods and the other involving protein corona formation in the protein-nanomaterial system. The study, for the first time, explores multilayer protein corona on a nanoparticle surface and provides new insights into the mechanisms involving protein aggregation in the presence of the nanoparticles.

Controlled drug release and synergistic therapies have an important impact on improving therapeutic efficacy in cancer theranostics. Herein, a new near-infrared (NIR) light-controlled multi-functional nanoplatform (GNR@mSiO2-DOX/PFP@PDA) was developed for synergistic chemo-photothermal therapy (PTT) of tumours. In this nano-system, doxorubicin hydrochloride (DOX) and perfluoro-n-pentane (PFP) were loaded into the channels of mesoporous SiO2 simultaneously as a first step. A polydopamine (PDA) layer as the gatekeeper was coated on their surface to reduce premature release of drugs at physiological temperature. Upon 808 nm NIR irradiation, the gold nanorods (GNR) in the core of the nanoplatform show high photothermal conversion efficiency, which not only can provide the heat for PTT, but also can decompose the polymer PDA to allow DOX release from the channels of mesoporous SiO2. Most importantly, the photothermal conversion of GNR can also lead the liquid–gas phase transition of PFP to generate bubbles to accelerate the release of DOX, which can realize the chemotherapy of tumours. The subsequent synergistic chemo-PTT (contributed by the DOX and GNR) shows good anti-cancer activity. This work shows that the NIR-triggered multi-functional nanoplatform is of capital significance for future potential applications in drug delivery and cancer treatment.

Low-energy electrons (Auger electrons) can be produced via the interaction of photons with gold atoms in gold nanorods (AuNRs). These electrons are similar to those emitted during the decay of technetium-99m (99mTc), a radioactive nuclide widely used for diagnostics in nuclear medicine. Auger and internal conversion (IC) electron emitters appropriately targeted to the DNA of tumors cells may, therefore, represent a new radiotherapeutic approach. 99mTc radiopharmaceuticals, which are used for diagnosis, could indeed be used in theragnostic fields when loaded on AuNRs and delivered to a tumor site. This work aims to provide a proof of concept (i) to evaluate AuNRs as carriers of 99mTc-based radiopharmaceuticals, and (ii) to evaluate the efficacy of Auger electrons emitted by photon-irradiated AuNRs in inducing radio-induced damage in T98G cells, thus mimicking the effect of Auger electrons emitted during the decay of 99mTc used in clinical settings. Data are presented on AuNRs’ chemical characterization (with an aspect ratio of 3.2 and Surface Plasmon Resonance bands at 520 and 680 nm) and the loading of pharmaceuticals (after 99mTc decay) on their surface. Spectroscopic characterizations, such as UV-Vis and synchrotron radiation-induced X-ray photoelectron (SR-XPS) spectroscopies, were performed to investigate the drug–AuNR interaction. Finally, preliminary radiobiological data on cell killing with AuNRs are presented.

Bacterial infections have become a fatal threat because of the abuse of antibiotics in the world. Various gold (Au)-based nanostructures have been extensively explored as antibacterial agents to combat bacterial infections based on their remarkable chemical and physical characteristics. Many Au-based nanostructures have been designed and their antibacterial activities and mechanisms have been further examined and demonstrated. In this review, we collected and summarized current developments of antibacterial agents of Au-based nanostructures, including Au nanoparticles (AuNPs), Au nanoclusters (AuNCs), Au nanorods (AuNRs), Au nanobipyramids (AuNBPs), and Au nanostars (AuNSs) according to their shapes, sizes, and surface modifications. The rational designs and antibacterial mechanisms of these Au-based nanostructures are further discussed. With the developments of Au-based nanostructures as novel antibacterial agents, we also provide perspectives, challenges, and opportunities for future practical clinical applications.

The versatile combination of metal nanoparticles with chemotherapy agents makes designing multifunctional drug delivery systems attractive. In this work, we reported cisplatin’s encapsulation and release profile using a mesoporous silica-coated gold nanorods system. Gold nanorods were synthesized by an acidic seed-mediated method in the presence of cetyltrimethylammonium bromide surfactant, and the silica-coated state was obtained by modified Stöber method. The silica shell was modified first with 3-aminopropyltriethoxysilane and then with succinic anhydride to obtain carboxylates groups to improve cisplatin encapsulation. Gold nanorods with an aspect ratio of 3.2 and silica shell thickness of 14.74 nm were obtained, and infrared spectroscopy and ζ potential studies corroborated surface modification with carboxylates groups. On the other hand, cisplatin was encapsulated under optimal conditions with an efficiency of ~58%, and it was released in a controlled manner over 96 h. Furthermore, acidic pH promoted a faster release of 72% cisplatin encapsulated compared to 51% in neutral pH.

A nanocomposite based on silica-coated AuNRs with the aminated silica-covered spin-crossover nanoparticles (SCO NPs) of the 1D iron(II) coordination polymer with the formula [Fe(Htrz)2(trz)](BF4) is presented. For the synthesis of the SCO NPs, the reverse micelle method was used, while the gold nanorods (AuNRs) were prepared with the aspect ratio AR = 6.0 using the seeded-growth method and a binary surfactant mixture composed of cetyltrimethylammonium bromide (CTAB) and sodium oleate (NaOL). The final nanocomposite was prepared using the heteroaggregation method of combining different amounts of SCO NPs with the AuNRs. The nonlinear optical (NLO) properties of the hybrid AuNRs coated with different amounts of SCO NPs were studied in detail by means of the Z-scan technique, revealing that the third-order NLO properties of the AuNRs@SCO are dependent on the amount of SCO NPs grafted onto them. However, due to the resonant nature of the excitation, SCO-induced NLO switching was not observed.

Gold nanorods (AuNRs) are ideal inorganic nanophotothermal agents with unique characteristics, including local surface plasmon resonance effects, easy scale preparation and functional modification, and good biocompatibility. This review summarizes several recent advances in AuNRs-based photothermal therapy (PTT) research. Functionalized AuNRs photothermal agents have optimized biocompatibility and targeting properties. The multifunctional AuNRs nanoplatform composite structure meets the requirements for synergistic effects of PTT, photoacoustic imaging, and other therapeutic methods. Photothermal therapy with AuNRs (AuNRs-PTT) is widely used to treat tumors and inflammatory diseases; its tumor-targeting, tumor metastasis inhibition, and photothermal tumor ablation abilities have remarkable curative effects. An in-depth study of AuNRs in living systems and the interactions between biological structure, nanomaterial, and near-infrared irradiation could lay the foundation for further clinical research and the broad application of AuNRs in PTT. [ABSTRACT FROM AUTHOR]

The development of chemo/photothermal nanotherapeutic systems with excellent photothermal performance, stable drug loading, tumor targeting and strong membrane penetration still remains a challenge. To address this problem, herein a rod-like nanocomposite system (AuNR@FA-PR/PEG) forming from folic acid (FA) terminated carboxylated cyclodextrin (CD) pseudopolyrotaxane (FA-PR) and polyethylene glycol (PEG) modifying gold nanorods (AuNR) was reported. Cisplatin (CDDP) was loaded in AuNR@FA-PR/PEG via coordination bonds to prepare a rod-like pH-responsive nanosystem (AuNR@FA-PR/PEG/CDDP) with chemotherapy/photothermal therapy. The rod-like morphology of AuNR@FA-PR/PEG was characterized by transmission electron microscope. In vitro drug release experiments showed the pH-responsive of AuNR@FA-PR/PEG/CDDP. In vivo real-time imaging assays proved AuNR@FA-PR/PEG/CDDP could rapidly enrich in the tumor area and stay for a long time because of folate targeting and their rod-like morphology. In vivo photothermal imaging assays showed AuNR@FA-PR/PEG/CDDP excellent photothermal performance, the average temperature of tumor region could reach 63.5 °C after 10 min irradiation. In vitro and in vivo experiments also demonstrated that the combined therapy of chemotherapy and photothermal therapy had an outstandingly synergistic effect and improved the therapeutic efficacy comparing with chemotherapy and photothermal therapy alone. Therefore, the prepared rod-like AuNR@FA-PR/PEG/CDDP will provide a new strategy for the effective treatment of cancer. [ABSTRACT FROM AUTHOR]

Plasmonic nanoparticle assemblies are promising functional materials for surface‐enhanced Raman spectroscopy (SERS). Gold nanorod (AuNR) assemblies are of particular interest due to the large, shape‐induced local field enhancement and the tunable surface plasmon resonance of the AuNRs. Designing the optimal assembly structure for SERS, however, is challenging and requires a delicate balance between the interparticle distance, porosity, and wetting of the assembly. Here, a new type of functional assemblies–called supraparticles–fabricated through the solvent‐evaporation driven assembly of silica‐coated gold nanorods into spherical ensembles, in which the plasmonic coupling and the mass transport is tuned through the thickness and porosity of the silica shells are introduced. Etching of the AuNRs allowed fine‐tuning of the plasmonic response to the laser excitation wavelength. Using a correlative SERS‐electron microscopy approach, it is shown that all supraparticles successfully amplified the Raman signal of the crystal violet probe molecules, and that the Raman signal strongly increased when decreasing the silica shell thickness from 35 to 3 nm, provided that the supraparticles have a sufficiently high porosity. The supraparticles introduced in this study present a novel class of materials for sensing, and open up a wide parameter space to optimize their performance. [ABSTRACT FROM AUTHOR]

Gold nanorods (AuNRs) were synthesized by the seed-mediated wet chemical method using a binary surfactant system. AuNRs were stabilized with polyethylene glycol, then functionalized with 4-mercaptophenol (4-MPH) ligand by surface ligand exchange. The surface-functionalized AuNRs (4-MPH-AuNRs) exhibited a typical UV–vis spectrum of AuNRs with a slightly shifted longitudinal peak. Furthermore, 4-MPH-AuNRs demonstrated a similar Fourier-Transformed Infrared spectrum to 4-MPH and a fading of the thiol band, which suggests a successful functionalization through thiol-gold binding. The antibacterial and antibiofilm activities of 4-MPH-AuNRs were evaluated against a clinical isolate of Methicillin-Resistant Staphylococcus aureus (MRSA). The results indicate that 4-MPH-AuNRs exhibit a bactericidal activity with a minimum inhibitory concentration (MIC) of ~ 6.25 μ g/mL against a planktonic suspension of MRSA. Furthermore, 4-MPH-AuNRs resulted in a 1.8–2.9 log-cycle reduction of MRSA biofilm viable count over a concentration range of 100–6.0 μ g/mL. The bacterial uptake of the surface-modified nanorods was investigated by inductively coupled plasma-optical emission spectroscopy (ICP-OES) and scanning electron microscopy (SEM) imaging; the results reveal that the nanorods were internalized into the bacterial cells after 6 h (h) of exposure. SEM imaging revealed a significant accumulation of the nanorods at the bacterial cell wall and a possible cellular internalization. Thus, 4-MPH-AuNRs can be considered a potential antibacterial agent, particularly against MRSA strain biofilms. [ABSTRACT FROM AUTHOR]

The ligand exchange process on gold nanorods (Au NRs) was explored by using laser desorption/ionization time-of-flight mass spectrometry (LDI-TOF-MS). Cetyltrimethylammonium bromide (CTAB) adsorbed on Au NRs was replaced with alkanethiol derivatives presenting different functional groups. The ligand exchange process was investigated under various conditions, such as in the presence of different functional groups in the ligands and with different concentrations of CTAB. The ligand-exchanged Au NRs were characterized by using a combination of UV–Vis spectroscopy and LDI-TOF-MS. Based on the results, it was revealed that LDI-TOF-MS analysis can provide crucial and distinct information about the degree of ligand exchange on Au NRs. [ABSTRACT FROM AUTHOR]

[Display omitted] Extracellular vesicles (EVs) and cell membrane nanoghosts are excellent coatings for nanomaterials, providing enhanced delivery in the target sites and evasion of the immune system. These cell-derived coatings allow the exploration of the delivery properties of the nanoparticles without stimulation of the immune system. Despite the advances reported on the use of EVs and cell-membrane coatings for nanomedicine applications, there are no standards to compare the benefits and main differences between these technologies. Here we investigated macrophage-derived EVs and cell membranes-coated gold nanorods and compared both systems in terms of target delivery in cancer and stromal cells. Our results reveal a higher tendency of EV-coated nanorods to interact with macrophages yet both EV and cell membrane-coated nanorods were internalized in the metastatic breast cancer cells. The main differences between these nanoparticles are related to the presence or absence of CD47 in the coating material, not usually addressed in EVs characterization. Our findings highlight important delivery differences exhibited by EVs- or cell membranes- coated nanorods which understanding may be important to the design and development of theragnostic nanomaterials using these coatings for target delivery. [ABSTRACT FROM AUTHOR]

In the present study, we developed a novel colorimetric strategy for the visible rapid detection of the influenza virus based on the unique optical properties of gold nanorods. Specifically, lipoic acid-modified Oseltamivir (OS), which is a strong neuraminidase inhibitor and used as the first-line drug in the treatment of influenza, was synthesized and further attached to the surface of gold nanorods (OS-LA-GNRs). The absorption band and density of OS-LA-GNRs were changed with the decreasing distance between the nanoparticles induced by the target-specific aggregation via strong neuraminidase–OS binding. All of these could be visible with the naked eyes and measured by UV-visible spectrophotometry. The results showed that our system had a comparable limit of detection (LOD) to the commercial colloidal gold stripes, making it feasible for wide diagnostic applications. [ABSTRACT FROM AUTHOR]

Any excess or lack of human serum albumin (HSA) in urine should be considered a warning for renal or cardiovascular diseases. This report proposes a rapid and straightforward method for detecting HSA based on the surface plasmon resonance characteristics and sensitivity of antibody-functionalized gold nanorods (GNRs) to trace changes in the local environment. The role of potential parameters (e.g., pH, the concentration of antibody, and the blocking agent) was also studied to optimize the sensor performance. The nanobiosensor determined HSA in the 30–300 μg·mL−1 concentration range with a detection limit of 1 μg·mL−1 and exhibited high selectivity towards HSA. This nanobiosensor has a detection limit within the reference range required to detect microalbuminuria or macroalbuminuria. The developed nanobiosensor also showed the possibility of tracing HSA in urine samples with 95–100% accuracy. This investigation introduces a potential application of gold nanorod-based sensors as promising alternatives for conventional methods in the form of a new generation of facile, rapid, and "lab-in-a-vial" nanodiagnostic technique. [ABSTRACT FROM AUTHOR]

Chemical interface damping (CID) is the most recently suggested plasmon damping pathway induced by adsorbate molecules in gold nanoparticles. Despite recent advances in this field, CID has not been studied in gold nanorods coated with mesoporous silica shells (AuNRs@mSiO2). Herein, we conducted a single‐particle correlation study to elucidate CID using p‐nitrothiophenol (p‐NTP) as adsorbates in single AuNRs@mSiO2. Through surface‐enhanced Raman spectroscopy studies, we confirmed that p‐NTP with a strong electron‐withdrawing group was effectively adsorbed on the AuNR cores. Following the chemisorption of p‐NTP, a strong CID was observed with localized surface plasmon resonance (LSPR) linewidth broadening through the preferred interaction between sulfur and the Au surfaces. Furthermore, we presented the molecular binding effect on the LSPR linewidth of single AuNRs@mSiO2 during the reaction with p‐NTP in real‐time. Thus, the result further supported that the CID could be used to develop LSPR sensors having low sensitivity to the medium dielectric constant. [ABSTRACT FROM AUTHOR]

Gold nanorods (GNRs) show promising biomedical therapeutic/imaging applications. This study investigated the effect of PEGylated-GNRs on the angiogenesis factors: vascular endothelial growth factor (VEGF) and platelet derived growth factor (PDGF) and their regulator (miR-29a-3p) under variable administration conditions--dosage, gender, routes of administration, and post-treatment intervals. In CD-1 mice of both genders, PEG-GNRs (94, 375, 750, and 1500 ng/kg body weight, ~40 nm, aspect ratio ~4.5) were injected via different routes: intravenous, subcutaneous, and intramuscular, and then VEGF and PDGF were estimated in sera by ELISA, after post-treatment intervals (1, 3, and 7 days). Low doses of PEG-GNRs (94 and 375 ng/kg body weight) resulted in antiangiogenic effects, while the highest dose (1500 ng/kg body weight) provoked a pro-angiogenic effect, especially in females and with intravenous route. The expression of miR-29a was significantly diminished in intravenous (IV) and intramuscular (IM) groups at day 7, in both males and females. miR-29a may be responsible for the increased VEGF in the highest PEGGNRs dose, but it is not responsible for the inhibited VEGF and PDGF levels in low PEG-GNRs doses. The study recommends the consideration of the critical role of dose, gender, and route of administration in PEG-GNRs pro-angiogenic activity, in medical applications as a direct cancer therapy and as a drug delivery agent. [ABSTRACT FROM AUTHOR]

To improve the therapeutic efficacy of breast cancer (BC), an intelligent tri-responsive vehicle based on core–shell structured gold nanorods (GNR)@mesoporous SiO2 (MS)@hyaluronic acid (HA) is proposed for controlled delivery of methotrexate (MTX). The characterization of the resultant GNR@MS@HA is systematically investigated. GNR is used for photothermal conversion under near-infrared light (NIR) irradiation, and the produced hyperthermia can lead to the ablation of cancer cells. MTX can be encapsulated in the mesopores of MS with the aid of HA, which is grafted to the surface of aminated MS (MS-NH2) through amidation reaction. The proposed vehicle can be used for MTX release in the tri-response of pH, NIR, and hyaluronidase (HAase) and integrates photothermal therapy and chemotherapy so as to improve the inhibition rate of cancer cells. The results of cell viability experiments demonstrate that the developed tri-responsive vehicle displays excellent biocompatibility to L929 mouse fibroblasts while exhibiting high chemo-photothermal synergistic therapy efficiency against murine BC cells (4T1). [ABSTRACT FROM AUTHOR]

The residual strain induced during the growth of perovskite film is an intrinsic issue that significantly affects the efficiency and stability of perovskite solar cells (PVSCs). Inspired by the flipped annealing method to release strain in perovskite thin films, SiO2‐coated gold nanorods (GNR@SiO2) are introduced into perovskite film and advantage of the plasmonic local heating effect is taken for in situ strain relaxation. The GNR@SiO2‐incorporated inverted PVSCs exhibit a champion power conversion efficiency (PCE) over 23%, which is the highest PCE in plasmonic‐incorporated PVSCs. Moreover, the intrinsic stability of the resulting PVSCs is greatly improved for the nonencapsulated device and retains 84% of its initial PCE after 2800 h aging under continuous illumination at 65 ± 5 °C in an N2 glove box and nearly 90% after 1000 h repetitive 12 h light on–off cycles. This work provides an efficient yet easy‐to‐implement plasmonic heating strategy for simultaneously enhancing the efficiency and stability of PVSCs. [ABSTRACT FROM AUTHOR]

Photothermal application of gold nanorods (AuNRs) is widely increasing because of their good photothermal conversion efficiency (PCE) due to local surface plasmon resonance. However, the high concentration of hexadecyltrimethylammonium bromide used in the synthesis is a concern. Moreover, the mild and commonly used reducing agent-ascorbic acid does not reduce the Au(I) to A(0) entirely, resulting in a low yield of gold nanorods. Herein we report for the first time the PCE of large-scaled synthesized AuNRs using the binary surfactant seed-mediated method with hydroquinone (HQ) as the reducing agent. The temporal evolution of the optical properties and morphology was investigated by varying the Ag concentration, HQ concentration, HCl volumes, and seed solution volume. The results showed that the seed volume, HQ concentration, and HCl volume played a significant role in forming mini-AuNRs absorbing in the 800 nm region with a shape yield of 87.7%. The as-synthesized AuNRs were successfully up-scaled to a larger volume based on the optimum synthetic conditions followed by photothermal profiling. The photothermal profiling analysis showed a temperature increase of more than 54.2 °C at 2.55 W cm−2 at a low optical density (OD) of 0.160 after 630 s irradiation, with a PCE of approximately 21%, presenting it as an ideal photothermal agent. [ABSTRACT FROM AUTHOR]

[Display omitted] • It is the first time to propose the guiding role of rhodamine 6G on formation of counterintuitive assembly of gold nanorods. • By comparing the aggregates of rhodamine 6G, H-dimer is determined to be the main inducing factor for the self-assembly. • A novel zigzag chain composed of three H-dimers in between gold nanorods induces the self-assembly. Self-assembled nanostructures with highly ordered and diversified patterns can be obtained by adding additives that directionally control the interparticle interactions. However, due to the complex non-covalent weak interactions in the self-assembly process, the active mechanism of additives is not fully understood, resulting in the limitation of obtaining the nano-superstructures. The introduction of rhodamine 6G (R6G) enables gold nanorods (GNRs) self-assembled into a counterintuitive tetragonal superlattice, during which the exploration of the influence of R6G molecular interactions on the GNRs self-assembly is of importance. We present the detailed investigations of spacial configuration, binding modes, and aggregated degree of R6G molecule on formation of the tetragonal GNRs superlattices by combining the experimental and simulated results. By analyzing the peak position and peak intensity in the fluorescent spectra of assembled samples and pure R6G samples, H-dimer is verified as the main cause for inducing the tetragonal superstructures. Molecular dynamics simulations reveal that 2–3 H-dimers adsorbed obliquely in a zigzag chain manner on the surface of GNRs is the most stable state of the self-assembly. This work would contribute to a deeper understanding of the complex colloidal nanoparticle self-assemblies and push forward the development of the bottom-up nanoscale superstructures. [ABSTRACT FROM AUTHOR]

Multidrug‐resistant bacteria have become a global health problem for which new prophylactic strategies are now needed, including surface‐coatings for hospital spaces and medical equipment. This work reports the preparation and functional validation of a metal‐organic framework (MOF) based composite for the triggered controlled release of iodine, an antimicrobial element that does not generate resistance. It comprises beads of the iodophilic MOF UiO‐66 containing encapsulated gold nanorods (AuNRs) coated with a silica shell. Irradiation of the AuNRs with near‐infrared light (NIR) provokes a photothermal effect and the resultant heat actively liberates the iodine. After validating the performance of this composite, it is integrated into a polymer for the development of antibacterial films. This work assesses the adsorption of iodine into these composite films, as well as its passive long‐term release and active light‐triggered. Finally, this work validates the antibacterial activity of the composite films in vitro against gram‐positive and gram‐negative bacteria. The findings will surely inform the development of new prophylactic treatments. [ABSTRACT FROM AUTHOR]

Background: Injectable hydrogels have great promise in the treatment of myocardial infarction (MI); however, the lack of electromechanical coupling of the hydrogel to the host myocardial tissue and the inability to monitor the implantation may compromise a successful treatment. The introduction of conductive biomaterials and mesenchymal stem cells (MSCs) may solve the problem of electromechanical coupling and they have been used to treat MI. In this study, we developed an injectable conductive nanocomposite hydrogel (GNR@SN/Gel) fabricated by gold nanorods (GNRs), synthetic silicate nanoplatelets (SNs), and poly(lactide-co-glycolide)-b-poly (ethylene glycol)-b-poly(lactide-co-glycolide) (PLGA-PEG-PLGA). The hydrogel was used to encapsulate MSCs and 68Ga3+ cations, and was then injected into the myocardium of MI rats to monitor the initial hydrogel placement and to study the therapeutic effect via 18F-FDG myocardial PET imaging. Results: Our data showed that SNs can act as a sterically stabilized protective shield for GNRs, and that mixing SNs with GNRs yields uniformly dispersed and stabilized GNR dispersions (GNR@SN) that meet the requirements of conductive nanofillers. We successfully constructed a thermosensitive conductive nanocomposite hydrogel by crosslinking GNR@SN with PLGA2000-PEG3400-PLGA2000, where SNs support the proliferation of MSCs. The cation-exchange capability of SNs was used to adsorb 68Ga3+ to locate the implanted hydrogel in myocardium via PET/CT. The combination of MSCs and the conductive hydrogel had a protective effect on both myocardial viability and cardiac function in MI rats compared with controls, as revealed by 18F-FDG myocardial PET imaging in early and late stages and ultrasound; this was further validated by histopathological investigations. Conclusions: The combination of MSCs and the GNR@SN/Gel conductive nanocomposite hydrogel offers a promising strategy for MI treatment. [ABSTRACT FROM AUTHOR]

Nanoparticle mediated laser induced breakdown can be used for Nanoparticle synthesis, cell nanosurgery and laser induced breakdown spectroscopy. To investigate the photo-thermal conversion of gold nanoparticles during pulsed laser irradiation, the electron-phonon two temperature model was established in this study. The impact of laser energy density and pulse width on the thermal conversion and morphology change of gold nanorods were investigated and compared with experimental observations. The results show that the melting threshold of gold nanorods under nanosecond laser irradiation is about twenty times that of femtosecond laser irradiation. The mechanisms of nanorod fragmentation are different between femto and nanosecond laser irradiation: particle melting is more likely to occur in nanosecond laser irradiation, while the Coulomb explosion is highly likely to occur in femtosecond laser irradiation. [ABSTRACT FROM AUTHOR]

This study aimed to determine the β-lactam antibiotics (ampicillin, amoxicillin, penicillin G, oxacillin, and carbenicillin) using conjugated antibody along with gold nanorods (AuNRs). For this purpose, XRD, ATR-FTIR spectroscopy, transmission electron microscopy, and dynamic light scattering were utilized to detect the crystallinity, to identify functional groups involved in the synthesis of AuNRs, and to measure the size of the AuNRs, respectively. In this regard, pH of 9 and a concentration of 9.6 μg of antibody at 1 mL poly(4-styrenesulfonic acid (PSS))-modified AuNRs solution were selected as the best levels of pH and concentration of antibody for the conjugation of antibody with PSS-modified AuNRs. Thereafter, the maximum wavelength rates of the PSS-modified AuNRs, conjugation of antibody with PSS-modified AuNRs, and detection of antibiotics (from 1 nM to 1 mM) with PSS-modified AuNRs–PAb were recorded using a microvolume spectrophotometer system. The results indicate that the LSPR absorption wavelength of PSS-modified AuNRs is red-shifted by increasing the concentration of β-lactam antibiotics. By increasing the concentrations of ampicillin, penicillin G, and carbenicillin, the maximum wavelength changed, and after the saturation of the antibiotic concentration, the curve reached a plateau. Correspondingly, this indicated that the antibody had a similar behavior in the detection of these antibiotics. However, regarding amoxicillin, the saturation concentration is much higher, which indicate that the antibody is more specific for its detection. In contrast, for oxacillin, saturation occurred immediately, demonstrating that the antibody had an extremely low detection capability for this antibiotic. Finally, the findings showed that the antibody was sensitive to 1 nM of five studied β-lactam antibiotics. [ABSTRACT FROM AUTHOR]

Until now, the ability to form a self-assembled monolayer (SAM) on a surface has been investigated according to deposition techniques, which in turn depend on surface-coater interactions. In this paper, we pursued two goals: to form a SAM on a gold nanosurface and to correlate its formation to the nanosurface curvature. To achieve these objectives, gold nanoparticles of different shapes (spheres, rods, and triangles) were functionalized with a luminescent thiolated bipyridine (Bpy-SH), and the SAM formation was studied by investigating the photo-physics of Bpy-SH. We have shown that emission wavelength and excited-state lifetime of Bpy-SH are strongly correlated to the formation of specific aggregates within SAMs, the nature of these aggregates being in close correlation to the shape of the nanoparticles. Micro-Raman spectroscopy investigation was used to test the SERS effect of gold nanoparticles on thiolated bipyridine forming SAMs. [ABSTRACT FROM AUTHOR]

Tumor recurrence after surgery is the main cause of treatment failure. However, the initial stage of recurrence is not easy to detect, and it is difficult to cure in the late stage. In order to improve the life quality of postoperative patients, an efficient synergistic immunotherapy was developed to achieve early diagnosis and treatment of post-surgical tumor recurrence, simultaneously. In this paper, two kinds of theranostic agents based on gold nanorods (AuNRs) platform were prepared. AuNRs and quantum dots (QDs) in one agent was used for the detection of carcinoembryonic antigen (CEA), using fluorescence resonance energy transfer (FRET) technology to indicate the occurrence of in situ recurrence, while AuNRs in the other agent was used for photothermal therapy (PTT), together with anti-PDL1 mediated immunotherapy to alleviate the process of tumor metastasis. A series of assays indicated that this synergistic immunotherapy could induce tumor cell death and the increased generation of CD3+/CD4+ T-lymphocytes and CD3+/CD8+ T-lymphocytes. Besides, more immune factors (IL-2, IL-6, and IFN-γ) produced by synergistic immunotherapy were secreted than mono-immunotherapy. This cooperative immunotherapy strategy could be utilized for diagnosis and treatment of postoperative tumor recurrence at the same time, providing a new perspective for basic and clinical research.

Abstract Cancer is one of the most common incident in the world, with malignant tumors having a death rate of up to 19%. A new method of treating cancer cells effectively with minimal cytotoxicity is needed. In the field of biomedicine with unique shape-dependent optical properties, gold nanorods (GNRs) have attracted worldwide interest. These nanorods have two distinct plasmon bands. One is transverse plasmon band in the area of visible light, and the other is longitudinal band of plasmons in near infrared region. These specific characters provide promise for the design of new optically active reagents that simultaneously perform light-mediated imaging and photothermal cancer treatment. We begin our review by summarizing the latest developments in gold nanorods synthesis with a focus on seed-mediated growth method. Nanorods spontaneous self-assembly, polymer-based alignment and its applications as a novel agent for simultaneous bioimaging and photothermal cancer therapy are listed in particular.

Abstract Background The biomedical field has used gold nanorods (GNRs) for decades; however, clinical trials and translation is limited except gold nanoshells. The preparation of gold nanoshells is more complex than that of polyethylene glycol-modified GNRs (PEG-GNRs), and it is difficult to ensure uniform thickness. It is important to encourage and broaden the use of the star member (PEG-GNRs) of gold nanoparticles family for clinical translation. Existing studies on PEG-GNRs are limited with no relevant systematic progression in non-human primates. Herein, we assessed the systematic biocompatibility of PEG-GNRs in rats and clinically relevant Macaca fascicularis. Results In this small animal study, we administrated multiple doses of PEG-GNRs to rats and observed good biocompatibility. In the non-human primate study, PEG-GNRs had a longer blood half-life and produced a negligible immune response. Histological analysis revealed no significant abnormality. Conclusions PEG-GNRs were well-tolerated with good biocompatibility in both small animals and large non-human primates. The information gained from the comprehensive systemic toxicity assessment of PEG-GNRs in M. fascicularis will be helpful for translation to clinical trials. Graphical abstract

Sarka Salajkova,1,2 Filip Havel,1,3 Michal Sramek,1 Filip Novotny,1,4 David Malinak,2,5 Rafael Dolezal,2,5 Lukas Prchal,2 Marketa Benkova,2 Ondrej Soukup,2 Kamil Musilek,2,5 Kamil Kuca,2,5 Jiri Bartek,1,6,7 Jan Proska,3 Monika Zarska,1 Zdenek Hodny1 1Department of Genome Integrity, Institute of Molecular Genetics of the Czech Academy of Sciences, Prague, Czech Republic; 2Biomedical Research Center, University Hospital Hradec Kralove, Hradec Kralove, Czech Republic; 3Department of Physical Electronics, Faculty of Nuclear Sciences and Physical Engineering, Czech Technical University in Prague, Prague, Czech Republic; 4Center for Advanced Functional Nanorobots, Department of Inorganic Chemistry, Faculty of Chemical Technology, University of Chemistry and Technology Prague, Prague, Czech Republic; 5Department of Chemistry, Faculty of Science, University of Hradec Kralove, Hradec Kralove, Czech Republic; 6Genome Integrity Unit, Danish Cancer Society Research Center, Copenhagen, Denmark; 7Department of Medical Biochemistry and Biophysics, Science for Life Laboratory, Division of Genome Biology, Karolinska Institute, Stockholm, SwedenCorrespondence: Monika ZarskaDepartment of Genome Integrity, Institute of Molecular Genetics of the Czech Academy of Sciences, Videnska 1083, Prague 4, Prague, CZ 142 20, Czech RepublicTel +420- 24106 3151Fax + 420-24106 2289Email monika.zarska@img.cas.czKamil KucaBiomedical Research Center, University Hospital Hradec Kralove, Sokolska 581, Hradec Kralove, CZ 500 05, Czech RepublicTel +420-495 833 447Email kamil.kuca@fnhk.czPurpose: Plasmonic photothermal cancer therapy by gold nanorods (GNRs) emerges as a promising tool for cancer treatment. The goal of this study was to design cationic oligoethylene glycol (OEG) compounds varying in hydrophobicity and molecular electrostatic potential as ligand shells of GNRs. Three series of ligands with different length of OEG chain (ethylene glycol units = 3, 4, 5) and variants of quaternary ammonium salts (QAS) as terminal functional group were synthesized and compared to a prototypical quaternary ammonium ligand with alkyl chain – (16-mercaptohexadecyl)trimethylammonium bromide (MTAB).Methods: Step-by-step research approach starting with the preparation of compounds characterized by NMR and HRMS spectra, GNRs ligand exchange evaluation through characterization of cytotoxicity and GNRs cellular uptake was used. A method quantifying the reshaping of GNRs was applied to determine the effect of ligand structure on the heat transport from GNRs under fs-laser irradiation.Results: Fourteen out of 18 synthesized OEG compounds successfully stabilized GNRs in the water. The colloidal stability of prepared GNRs in the cell culture medium decreased with the number of OEG units. In contrast, the cellular uptake of OEG+GNRs by HeLa cells increased with the length of OEG chain while the structure of the QAS group showed a minor role. Compared to MTAB, more hydrophilic OEG compounds exhibited nearly two order of magnitude lower cytotoxicity in free state and provided efficient cellular uptake of GNRs close to the level of MTAB. Regarding photothermal properties, OEG compounds evoked the photothermal reshaping of GNRs at lower peak fluence (14.8 mJ/cm2) of femtosecond laser irradiation than the alkanethiol MTAB.Conclusion: OEG+GNRs appear to be optimal for clinical applications with systemic administration of NPs not-requiring irradiation at high laser intensity such as drug delivery and photothermal therapy inducing apoptosis.Keywords: gold nanorods, quaternary ammonium salts, oligoethylene glycol, cellular uptake, photothermal stability

Combined the electrostatic interaction of the negatively charged gold nanorods (AuNRs) (as acceptor) and Ru(bpy) 3 2+ (as donor), an electrochemiluminescence resonance energy transfer (ECL-RET) sensor was constructed and applied for the detection of organophosphorus pesticides (OPs). Negatively charged AuNRs were synthesized by modifying AuNRs with polystyrene sulfonate (PSS) firstly, which can bind to Ru(bpy) 3 2+ through electrostatic interaction so that the luminophore was absorbed by the acceptor, the resonance energy transfer occurred and only low ECL signal had been detected. Thiocholine can be produced by the hydrolysis process of acetylthiocholine (ATCh) with the help of acetylcholinesterase (AChE), which can bond with PSS-modified AuNRs (PSS-AuNRs) through gold-sulfur interaction, this caused the releasing of the adsorbed Ru(bpy) 3 2+ into the solution and resulting in the restoration of the ECL intensity. However, the activity of AChE was inhibited by OPs, and the recovery process of the ECL signal was thus suppressed as well. In this study, chlorpyrifos was chosen as model target, the results indicated that the correlation between the ECL intensity and the logarithm of chlorpyrifos concentration showed remarkable linearity across 1 ng/mL to 1 mg/mL, achieving a detection limit of 0.51 ng/mL. The proposed system has been utilized for detecting OPs in real samples with satisfied results. An electrochemiluminescence sensor for organophosphorus pesticides based on the regulation of resonance energy transfer between negative charged gold nanorods and Ru(bpy) 3 2+ was developed. [Display omitted] • Electrochemiluminescence sensor for organophosphorus pesticides had been proposed. • The sensor was designed based on the regulation of resonance energy transfer. • The sensor had good selectivity in detecting organophosphorus pesticides in real samples. • The sensor avoided complex and time-consuming modification process. [ABSTRACT FROM AUTHOR]

[Display omitted] • An optical fiber sensor for SARS-CoV-2 N gene detection coated with gold nanorods has been prepared. • The sandwich structure was designed and demonstrated to couple particles side-to-side. • The sensor shows a wide detection range of 0.01 to 100 nm, and the limit of detection is 1 pM. • The response time of optical fiber sensor is 10 min and it performs well. A novel SARS-CoV-2 N gene optical fiber biosensor based on ASO-coated gold nanorods is proposed in this work. A fiber probe prepared by AuNRs self-assembly was used to detect N gene by complementary base pairing method. The detected material was processed into AuNRs-ASO2-N gene coupler by cross-linking, and the pairing of N gene with ASO1 connected to AuNRs on the surface of the optical fiber formed the hydrogen bonding. The coupling of AuNRs resulted in a left shift of the peak position and a decrease in absorbance in the LSPR spectrum. In this manuscript, it is verified for the first time by simulation and experimental characterization that the coupling mode of AuNRs on the surface of the optical fiber is side by side, which leads to a left shift of the peak position of the LSPR absorption peak on the optical fiber. It is also proved that sandwich method is superior to the traditional method of changing the refractive index. The response time of the sensor is 10 min, and the detection limit is 1 pM, and the results show that the optical fiber sensor based on ASO-coated AuNRs has excellent RNA detection performance in artificial body fluids and is very suitable for RNA detection. [ABSTRACT FROM AUTHOR]

Gold nanorod stain deposits have been studied using helium ion microscopy (HIM). The multilayer thick deposits can become well-organized monolayers when the density drops, as demonstrated by the density fluctuation of nanosuspension. However, once the density of nanoparticles approaches certain extremely low values, this tendency has disappeared. The difference in density associated with the liquid crystalline (LC) phases that have developed on the surface. There is a correlation between the density of nanoparticles in suspension and the relationship between droplet volume and UV-Vis absorbance. The physical characteristics that affect and generate such LC phases are contrasted and examined with the assembly method. To highlight noteworthy aspects, a quantitative comparison between the HIM analysis and the SEM is also made. Analyzing the correlation between the coffee stain range, nanoparticle density, and droplet contact angle is essential. It is possible to quantify the difference in the ring stains from the outside to the midle and from the midle to the inner boundary. HIM is typically useful when attempting to determine the true composition of surface deposits. The aim of this work is to investigate the effects of particle density on liquid crystalline superstructures and the coffee stain effect. [Display omitted] [ABSTRACT FROM AUTHOR]

Accurate assessment of Total Antioxidant Capacity (TAC) in food is crucial for evaluating nutritional quality and potential health benefits. This study aims to enhance the sensitivity and reliability of TAC detection through a dual-signal method, combining colorimetric and photothermal signals. Gold nanorods (AuNRs) were utilized to establish a dual-signal method duo to the colorimetric and photothermal properties. Fenton reaction can etch the AuNRs from the tips, as a result, a blue shift in the longitudinal LSPR absorption peak was obtained, leading to significant changes in color and photothermal effects, facilitating discrimination through both visual observation and thermometer measurements. In the presence of antioxidants, the Fenton reaction was suppressed or inhibited, protecting the AuNRs from etching. The colorimetric and photothermal signals were therefore positively correlated with TAC levels, enabling dual-signal detection of TAC. The linear range of AA was 4–100 μM in both colorimetry and photothermal modes, with detection limits of 1.60 μM and 1.38 μM, respectively. This dual-signal approach achieves low detection limits, enhancing precision and sensitivity. The method thus has the potential to act as a promising candidate for TAC detection in food samples, contributing to improved food quality and safety assessment. [Display omitted] • A multicolor and photothermal assay for Total Antioxidant Capacity (TAC) was developed. • The Fenton reaction was utilized to etch gold nanorods, inducing changes in both color and photothermal effects. • The method was successfully applied to TAC quantification in food samples. [ABSTRACT FROM AUTHOR]

Plasmonic photothermal therapy (PPTT) employing plasmonic gold nanorods (GNRs) presents a potent strategy for eradication of tumors including aggressive brain gliomas. Despite its promise, there is a pressing need for a more comprehensive evaluation of PPTT using sophisticated in vitro models that closely resemble tumor tissues, thereby facilitating the elucidation of therapeutic mechanisms. In this study, we exposed 3D glioma spheroids (tumoroids) to (16-mercaptohexadecyl)trimethylammonium bromide-functionalized gold nanorods (MTAB-GNRs) and a near-infrared (NIR) laser. We demonstrate that the photothermal effect can be fine-tuned by adjusting the nanoparticle concentration and laser power. Depending on the selected parameters, the laser can trigger either regulated or non-regulated cell death (necrosis) in both mouse GL261 and human U-87 MG glioma cell lines, accompanied by translocation of phosphatidylserine in the membrane. Our investigation into the mechanism of regulated cell death induced by PPTT revealed an absence of markers associated with classical apoptosis pathways, such as cleaved caspase 3. Instead, we observed the presence of cleaved caspase 1, gasdermin D, and elevated levels of NLRP3 in NIR-irradiated tumoroids, indicating the activation of pyroptosis. This finding correlates with previous observations of lysosomal accumulation of MTAB-GNRs and the known lysosomal pathway of pyroptosis activation. We further confirmed the absence of toxic breakdown products of GNRs using electron microscopy, which showed no melting or fragmentation of gold nanoparticles under the conditions causing regulated cell death. In conclusion, PPTT using coated gold nanorods offers significant potential for glioma cell elimination occurring through the activation of pyroptosis rather than classical apoptosis pathways. • PPTT using cationic MTAB-GNR effectively eliminates glioma cells in 3D spheroids. • The photothermal effect can be tuned to induce non-regulated or regulated cell death. • PPTT of MTAB-GNRs triggers an immunogenic form of cell death known as pyroptosis. • This suggests a potential synergy between PPTT and pyroptosis-mediated immunotherapy. [ABSTRACT FROM AUTHOR]

Herein we report a wearable sweat sensor of a Janus fabric based on surface enhanced Raman scattering (SERS) technology, mainly detecting the two important metabolites glucose and lactate. Janus fabric is composed of electrospinning PU on a piece of medical gauze (cotton), working as the unidirectional moisture transport component (R = 1305%) to collect and transfer sweat efficiently. SERS tags with different structures act as the probe to recognize and detect the glucose and lactate in high sensitivity. Core-shell structured gold nanorods with DTNB inside (AuNRs@DTNB@Au) are used to detect lactate, while gold nanorods with MPBA (AuNRs@MPBA) are used to detect glucose. Through the characteristic SERS information, two calibration functions were established for the concentration determination of glucose and lactate. The concentrations of glucose and lactate in sweat of a 23 years volunteer during three-stage interval running are tested to be 95.5, 53.2, 30.5 μM and 4.9, 13.9, 10.8 mM, indicating the glucose (energy) consumption during exercise and the rapid accumulation of lactate at the early stage accompanied by the subsequent relief. As expected, this sensing system is able to provide a novel strategy for effective acquisition and rapid detection of essential biomarkers in sweat. [ABSTRACT FROM AUTHOR]

Macrophages (Ma) loaded with gold based nanoparticles, which convert near infrared light to heat, have been studied as targeted transport vectors for photothermal therapy (PTT) of tumors. The purpose of the experiments reported here was to compare the efficacy of gold-silica nanoshells (AuNS) and gold nanorods (AuNR) in macrophage mediated PTT. PTT efficacy was evaluated in hybrid glioma spheroids consisting of human glioma cells and either AuNS or AuNR loaded Ma, designated MaNS and MaNR respectivly. Spheroids were irradiated for 10 min. with light from an 810 nm diode laser at irradiances ranging from 0 to 28 W/cm2. PTT efficacy was determined from spheroid growth over a 14-day period. The uptake by Ma of pegylated AuNR (3.9 ± 0.9 %) was twice that of pegylated AuNS, (7.9 ± 0.7 %). Hybrid spheroids consisting of a 5:1 ratio of glioma cells to loaded Ma exhibited significant growth inhibition with MaNS when subjected to irradiances of 7 W/cm2 or greater. In contrast, no significant growth inhibition was observed for the MaNR hybrid spheroids at this 5:1 ratio, even at the highest irradiance investigated (28 W/cm2). Although AuNR were taken up by Ma in larger numbers then AuNS, MaNS were shown to have greater PTT efficacy compared to MaNR for equivalent numbers of loaded Ma.