Gold nanostructures: synthesis, properties, and neurological applications

Zare I., Chevrier D.M., Cifuentes-Rius A., Moradi N., Xianyu Y., Ghosh S., Trapiella-Alfonso L., Tian Y., Shourangiz-Haghighi A., Mukherjee S., Fan K., Hamblin M.R.

The use of protein templates for the controlled synthesis of inorganic nanostructures has gained considerable attention in multidisciplinary fields, including electronics, optics, energy, sensing, and biomedicine, owing to their biocompatibility and structural programmability. The possible synergistic combination of protein scaffolds (and other biomolecules/biopolymers) with metal nanoclusters (MNCs) has created a new class of highly photoluminescent nanoprobes and nanodevices. For the first time, we will discuss the different types of protein templates used for MNC preparation with an emphasis on their optoelectronic properties for application. In particular, applications of protein-coated MNCs for chemosensing or biosensing of cancer biomarkers, neurotransmitters, pathogenic microorganisms, biomolecules, pharmaceutical compounds, and immunoassays are discussed in detail herein. Fluorescence-based and multimodal molecular imaging, both in vitro and in vivo based on functional proteins are also covered. Furthermore, we discuss the burgeoning growth of protein-coated MNCs ( e.g. , gold (Au) and silver (Ag) NCs) to develop synergistic nanotherapeutics with potential biomedical applications in chemotherapy, radiotherapy, photodynamic therapy (PDT), photothermal therapy (PTT), and antibacterial activity, as well as MNC-containing nanocomposites for enhanced bioimaging and controlled drug release. Overall, the proposed review highlights the recent progress, technical challenges and new horizons in this field, and summarizes our understanding of how MNC properties interact with the biological function of protein scaffolds to develop synergistic nanotherapeutics towards clinical translation.

Qian Y., Lin H., Yan Z., Shi J., Fan C.

Neuronal microenvironment imbalance is associated with successive and irreversible pathophysiological changes and insufficient functional restoration after peripheral nerve injury. Conventional neural-supporting scaffolds result in unsatisfactory curative effects due to lack of biomimetic nanotechnology designs and biochemical or physicochemical modifications. Consequently, they fail in rational and facile remodeling of the imbalanced growth microenvironment, and cannot recover neural structure and function. In recent years, with the increasing knowledge in neuronal injury-associated microenvironment, a number of novel strategies are applied in enhancing the biochemical and physicochemical natures of biomimetic nanomaterial-based scaffolds for nerve tissue engineering. These nanoscale scaffolds can trigger growth factor secretion and aggregation through surface modification, regulate ATP synthesis and hydrolysis, switch between oxidation and reduction states, and activate ion channels and stimulate electrical signals under certain biophysical cues. Consequently, they can determine neuronal cell fate by modulating their viability, development and cell cycles during the regeneration process. In this review, we systematically summarize the studies on the biomimetic scaffold design of functional nanomaterials, their basic topological, biochemical and physical properties, and nanotechnology-based restoration of a balanced nutritional microenvironment regarding four key neural regeneration factors, including immune response, intraneural vascularization, bioenergetic metabolism and bioelectrical conduction in order to provide ideas and inspiration for the nanomedicine-based neuronal regeneration therapy.

Nguyen T.T., Dung Nguyen T.T., Vo T.K., Tran N., Nguyen M.K., Van Vo T., Van Vo G.

Drug delivery to central nervous system (CNS) diseases is very challenging since the presence of the innate blood-brain barrier (BBB) and the blood-cerebrospinal fluid barrier that impede drug delivery. Among new strategies to overcome these limitations and successfully deliver drugs to the CNS, nanotechnology-based drug delivery platform, offers potential therapeutic approach for the treatment of some common neurological disorders like Alzheimer's disease, frontotemporal dementia, amyotrophic lateral sclerosis, Parkinson's disease, Huntington's disease. This review aimed to highlight advances in research on the development of nano-based therapeutics for their implications in therapy of CNS disorders. The challenges during clinical translation of nanomedicine from bench to bed side is also discussed.

Lira-Diaz E., Gonzalez-Pedroza M.G., Vasquez C., Morales-Luckie R.A., Gonzalez-Perez O.

• Gold nanoparticles (GNPs) produces a mild glial reactivity. • Intracerebral injection of GNPs induces a transient astrocytic response. • Microglial cells rapidly respond to GNPs, but this response declines in 14 days. • Glial response against GNPs is self-limited and mainly confined to the perilesional area. • GNPs may be good carriers to deliver long-lasting drugs into the brain. Gold nanoparticles (GNPs) have unique physical and chemical properties that allow them to function as a drug-delivery system for several tissues: skin, eye, liver, and others. However, information about the biological response of brain tissue against GNPs is limited. Astrocytes and microglia cells are the first line of defense against brain insults and proper indicators of the level of brain damage. This study was aimed to evaluate the astrocytic and microglia response after an intracerebral injection of polyethylene-glycol-coupled GNPs (PEGylated GNPs). We injected spherical PEGylated GNPs (85 × 10 6 nanoparticles /nl) with a glass micropipette (inner diameter =35 μm) into the striatum of P60 CD1 mice. We evaluated the cellular response of astrocytes and microglia on days 3, 7, 14, 30, and 90 after intracerebral injection. For both astrocytes and microglia cells, our findings indicated that the glial response was transient and mainly circumscribed to the injection site. This evidence suggests that PEGylated GNPs are well-tolerated by the neural tissue. Understanding the effects of GNPs in the adult brain is a crucial step to design proper pharmacological vehicles to deliver long-lasting drugs.

Moin A., Rizvi S.M., Hussain T., Gowda D.V., Subaiea G.M., Elsayed M.M., Ansari M., Alanazi A.S., Yadav H.

Objective: Brain tumors are the most challenging of all tumors and accounts for about 3% of all cancer allied deaths. The aim of the present review is to examine the brain tumor prevalence and treatment modalities available in the Kingdom of Saudi Arabia. It also provides a comprehensive analysis of the application of various nanotechnology-based products for brain cancer treatments along with their prospective future advancements. Methods: A literature review was performed to identify and summarize the current status of brain cancer in Saudi Arabia and the scope of nanobiotechnology in its treatment. Results: Depending upon the study population data analysis, gliomas, astrocytoma, meningioma, and metastatic cancer have a higher incidence rate in Saudi Arabia than in other countries, and are mostly treated in accordance with conventional treatment modalities for brain cancer. Due to the poor prognosis of cancer, it has an average survival rate of 2 years. Conventional therapy includes surgery, radiotherapy, chemotherapy, and a combination thereof, but these do not control the disease’s recurrence. Among the various nanomaterials discussed, liposomes and polymeric nanoformulations have demonstrated encouraging outcomes for facilitated brain cancer treatment. Conclusions: Nanomaterials possess the capacity to overcome the shortcomings of conventional therapies. Polymer-based nanomaterials have shown encouraging outcomes against brain cancer when amalgamated with other nano-based therapies. Nonetheless, nanomaterials could be devised that possess minimal toxicity towards normal cells or that specifically target tumor cells. In addition, rigorous clinical investigations are warranted to prepare them as an efficient and safe modality for brain cancer therapy.

Morales-Zavala F., Jara-Guajardo P., Chamorro D., Riveros A.L., Chandia-Cristi A., Salgado N., Pismante P., Giralt E., Sánchez-Navarro M., Araya E., Vasquez R., Acosta G., Albericio F., Alvarez R A., Kogan M.J.

The development and use of nanosystems is an emerging strategy for the diagnosis and treatment of a broad number of diseases, such as Alzheimer's disease (AD).

Chiang C., Shih I., Shueng P., Kao M., Zhang L., Chen S., Chen M., Liu T.

Although boron neuron capture therapy (BNCT) has enabled the delivery of stronger radiation dose to glioblastoma multiforme (GBM) cells for precision radiotherapy (RT), patients in need are almost unable to access the treatment due to insufficient operating devices. Therefore, we developed targeted sensitization-enhanced radiotherapy (TSER), a strategy that could achieve precision cell-targeted RT using common linear accelerators. TSER, which involves the combination of GoldenDisk (GD; a spherical radioenhancer), 5-aminolevulinic acid (5-ALA), low-intensity ultrasound (US), and low-dose RT, exhibited synergized radiosensitization effects. Both 5-ALA and hyaluronic-acid-immobilized GD can selectively accumulate in GBM to induce chemical and biological enhancement of radiosensitization, resulting in DNA damage, escalation of reactive oxygen species levels, and cell cycle redistribution, in turn sensitizing GBM cells to radiation under US. TSER showed an enhanced therapeutic effect and survival in the treatment of an orthotropic GBM model with only 20% of the radiation dose compared to that of a 10-Gy RT. The strategy with the potential to inhibit GBM progress and rescue the organ at risk using low-dose RT, thereby improving the quality of life of GBM patients, shedding light on achieving cell-targeted RT using universally available linear accelerators. We invented GoldenDisk (GD), a radioenhancer with hyaluronic-acid (HAc)-coated gold nanoparticle (AuNP)-core/silica shell nanoparticle, to make radiotherapy (RT) safer and smarter. The surface modification of HAc and silica allows GD to target CD44-overexpressed glioblastoma multiforme (GBM) cells and stay structurally stable in cytoplasm throughout the course of RT. By combining GD with low-energy ultrasound and an FDA-approved imaging agent, 5-aminolevulinic acid (5-ALA), GBM cells were sensitized to RT leaving healthy tissues in the vicinity unaffected. The ionized radiation can further be transferred to photoelectronic products with higher cytotoxicity by GD upon collision, achieving higher therapeutic efficacy. With the newly-developed strategy, we are able to achieve low-dose precision RT with the use of only 20% radiation dose.

Ghezzi M., Pescina S., Padula C., Santi P., Del Favero E., Cantù L., Nicoli S.

Polymeric micelles, i.e. aggregation colloids formed in solution by self-assembling of amphiphilic polymers, represent an innovative tool to overcome several issues related to drug administration, from the low water-solubility to the poor drug permeability across biological barriers. With respect to other nanocarriers, polymeric micelles generally display smaller size, easier preparation and sterilization processes, and good solubilization properties, unfortunately associated with a lower stability in biological fluids and a more complicated characterization. Particularly challenging is the study of their interaction with the biological environment, essential to predict the real in vivo behavior after administration. In this review, after a general presentation on micelles features and properties, different characterization techniques are discussed, from the ones used for the determination of micelles basic characteristics (critical micellar concentration, size, surface charge, morphology) to the more complex approaches used to figure out micelles kinetic stability, drug release and behavior in the presence of biological substrates (fluids, cells and tissues). The techniques presented (such as dynamic light scattering, AFM, cryo-TEM, X-ray scattering, FRET, symmetrical flow field-flow fractionation (AF4) and density ultracentrifugation), each one with their own advantages and limitations, can be combined to achieve a deeper comprehension of polymeric micelles in vivo behavior. The set-up and validation of adequate methods for micelles description represent the essential starting point for their development and clinical success. • Polymeric micelles represent a promising strategy to overcome several issues related to drug delivery • Polymeric micelles characterization in a biorelevant medium is fundamental to predict their behavior in vivo • A combination of techniques can be used to define micelles stability in the presence of body fluids, cells, and tissues

Báez D.F., Gallardo-Toledo E., Oyarzún M.P., Araya E., Kogan M.J.

Kumthekar P., Ko C.H., Paunesku T., Dixit K., Sonabend A.M., Bloch O., Tate M., Schwartz M., Zuckerman L., Lezon R., Lukas R.V., Jovanovic B., McCortney K., Colman H., Chen S., et. al.

RNA interference–based spherical nucleic acid nanoconjugates are a potentially safe and brain-penetrant approach for glioblastoma treatment.

Di Bella D., Ferreira J.P., Silva R.D., Echem C., Milan A., Akamine E.H., Carvalho M.H., Rodrigues S.F.

Sepsis is an emergency medical condition that can lead to death and it is defined as a life-threatening organ dysfunction caused by immune dysregulation in response to an infection. It is considered the main killer in intensive care units. Sepsis associated-encephalopathy (SAE) is mostly caused by a sepsis-induced systemic inflammatory response. Studies report SAE in 14–63% of septic patients. Main SAE symptoms are not specific and usually include acute impairment of consciousness, delirium and/or coma, along with electroencephalogram (EEG) changes. For those who recover from sepsis and SAE, impaired cognitive function, mobility and quality of life are often observed months to years after hospital discharge, and there is no treatment available today to prevent that. Inflammation and oxidative stress are key players for the SAE pathophysiology. Gold nanoparticles have been demonstrated to own important anti-inflammatory properties. It was also reported 20 nm citrate-covered gold nanoparticles (cit-AuNP) reduce oxidative stress. In this context, we tested whether 20 nm cit-AuNP could alleviate the acute changes caused by sepsis in brain of mice, with focus on inflammation. Sepsis was induced in female C57BL/6 mice by cecal ligation and puncture (CLP), 20 nm cit-AuNP or saline were intravenously (IV) injected 2 h after induction of sepsis and experiments performed 6 h after induction. Intravital microscopy was used for leukocyte and platelet adhesion study in brain, blood brain barrier (BBB) permeability carried out by Evans blue assay, cytokines measured by ELISA and real time PCR, cell adhesion molecules (CAMs) by flow cytometry and immunohistochemistry, and transcription factors, by western blotting. 20 nm cit-AuNP treatment reduced leukocyte and platelet adhesion to cerebral blood vessels, prevented BBB failure, reduced TNF- concentration in brain, and ICAM-1 expression both in circulating polymorphonuclear (PMN) leukocytes and cerebral blood vessels of mice with sepsis. Furthermore, 20 nm cit-AuNP did not interfere with the antibiotic effect on the survival rate of mice with sepsis. Cit-AuNP showed important anti-inflammatory properties in the brain of mice with sepsis, being a potential candidate to be used as adjuvant drug along with antibiotics in the treatment of sepsis to avoid SAE

He Y., Gao Q., Lv C., Liu L.

Herein, we report on the design and development of functionalized acrylic polymeric nanoparticles with Spiropyrans (SPs) and imidazole moieties via superficial polymerizations. Then, Au 3+ ions were immobilized and reduced on their surface to obtain photoresponsive gold-decorated polymer nanoparticles(Au-NPs). The synthesized Au-NPs were surface adapted with biotin as specific targeting tumor penetration cells and enhance the intercellular uptake through the endocytosis. FT-IR (Fourier-transform Infrared Spectroscopy), UV–Vis (Ultra Violet-Visible Spectrophotometer), EDS (Energy Dispersive X-Ray Spectroscopy), SEM (Scanning Electron Microscope) and HR-TEM (High-resolution transmission electron microscopy) descriptions were engaged to illustrate their spectral analysis and morphological examinations of Bt@Au-NPs. Fluorescence microscopy images of cellular uptake descriptions and ICP-MS (Inductively coupled plasma mass spectrometry) investigation established the cell lines labeling ability and enhanced targetting efficacy of biotin-conjugated Au-NPs (Bt@Au-NPs) toward C6 glioma cells (brain cancer cells) with 72.5% cellular uptake relative to 30.2% for non-conjugated lone. These were further established through intracellular ROS examinations and in vitro cytotoxicity investigation on the C6 glioma cell line. The solid surface plasmon absorptions of the Au-NPs and Bt@Au-NPs providing raised photothermal therapy under UV irradiation. The synthesized multifunctional Bt@Au-NPs with an inclusive combination of potential resources presented encouraging nanoprobe with targeting capability, improved photodynamic and photothermal cancer therapy. • The design and preparation of functionalized acrylic copolymer nanoparticles. • It shows the cell line labeling capability and improved targeting efficiency toward rat brain cancer cells. • Nonpolar SP groups are converted to zwitterionic merocyanine isomers under UV irradiation at 363 nm. • These were confirmed by intracellular ROS analysis and cytotoxicity evaluation on cancerous C6 glioma cells.

Niu Y., Ding T., Liu J., Zhang G., Tong L., Cheng X., Yang Y., Chen Z., Tang B.

The near-infrared fluorescence of gold nanoclusters stabilized with bovine serum albumin (BSA -AuNCs) centered at 675 nm could be enhanced by cysteine and then effectively quenched by copper ion (Cu 2+ ), therefore, cysteine and copper ion could be detected in sequence. At “on” state, fluorescence enhancement of BSA-AuNCs is generated due to the reaction between cysteine and BSA-AuNCs, via filling the surface defect of gold nanoclusters, while Cu 2+ can further oxidize the reductive sulfydryl of cysteine and interact with amino acids presented in the BSA chain, inducing gold nanoclusters to aggregate, thus causing “off” state with fluorescence quenching. Fluorescence switch of BSA-AuNCs can be used for cysteine and Cu 2+ detection in mice brain with Alzheimer's disease (AD) in vitro, with fast response, high chemical stability and sensitivity. Besides, it was able to image the endogenous Cu 2+ in liver and heart of AD mice in situ. The results are promising, especially in the framework of early diagnosis of Alzheimer's disease. • A simple “on-off” fluorescent probe of BSA-AuNCs was employed to detect cysteine and copper ions in sequence. • Cysteine and copper ion in mice brain with Alzheimer's disease were measured. • The established method is simple, sensitive and efficient.

Tapia-Arellano A., Gallardo-Toledo E., Ortiz C., Henríquez J., Feijóo C.G., Araya E., Sierpe R., Kogan M.J.

One of main drawbacks for the treatment of neurodegenerative pathologies is ensuring the delivery of therapeutic agents into the central nervous system (CNS). Nowadays, gold nanoprisms (GNPr) have become an emerging nanomaterial with a localized surface plasmon resonance in the biological window, showing applications in both detection and treatment of diseases. In this work, GNPr were functionalized with polyethylene glycol (PEG) and Angiopep-2 (Ang2) peptide to obtain a new highly stable nanomaterial and evaluate its toxicity and ability to cross the blood-brain barrier (BBB) in a zebrafish larvae model. The success in the functionalization was confirmed by a full characterization that showed the physicochemical changes at each step. In turn, the colloidal stability of GNPr-PEG-Ang2 in biologically relevant media also was demonstrated. The toxicity assays of GNPr-PEG-Ang2 performed on SH-SY5Y neuroblastoma cell line and on zebrafish larvae showed no effects both in vitro and in vivo . GNPr delivery to the CNS was studied in zebrafish larvae by immersion. We confirmed that functionalization with PEG-Ang2 improved the crossing through the BBB in this model compared with GNPr functionalized only with PEG. Notably, our nanomaterial was not detected in the CNS of zebrafish larvae 24 h after exposure that correlates with an adequate clearance of GNPr-PEG-Ang2 from the brain. This report is the first study of GNPr in the in vivo model of zebrafish larvae demonstrating that its functionalization with Ang2 allows the crossing of the BBB. Moreover, considering the stability achieved of the GNPr-PEG-Ang2 and the results of in vitro and in vivo studies, this work becomes a high contribution to the design of new nanomaterials with potential biomedical applications for CNS-related diseases. • Gold nanoprisms were functionalized with PEG and Angiopep-2 peptide (GNPr-PEG-Ang2). • This new nanomaterial is highly stable in biologically relevant media. • GNPr-PEG-Ang2 has no cytotoxic effects in vitro and do not show toxicity in vivo . • Ang2 improves GNPr crossing through the blood-brain barrier in zebrafish larvae.

Akhtar A., Andleeb A., Waris T.S., Bazzar M., Moradi A., Awan N.R., Yar M.

The central nervous system (CNS) encompasses the brain and spinal cord and is considered the processing center and the most vital part of human body. The central nervous system (CNS) barriers are crucial interfaces between the CNS and the periphery. Among all these biological barriers, the blood-brain barrier (BBB) strongly impede hurdle for drug transport to brain. It is a semi-permeable diffusion barrier against the noxious chemicals and harmful substances present in the blood stream and regulates the nutrients delivery to the brain for its proper functioning. Neurological diseases owing to the existence of the BBB and the blood-spinal cord barrier have been terrible and threatening challenges all over the world and can rarely be directly mediated. In fact, drug delivery to brain remained a challenge in the treatment of neurodegenerative (ND) disorders, for these different approaches have been proposed. Nano-fabricated smart drug delivery systems and implantable drug loaded biomaterials for brain repair are among some of these latest approaches. In current review, modern approaches developed to deal with the challenges associated with transporting drugs to the CNS are included. Recent studies on neural drug discovery and injectable hydrogels provide a potential new treatment option for neurological disorders. Moreover, induced pluripotent stem cells used to model ND diseases are discussed to evaluate drug efficacy. These protocols and recent developments will enable discovery of more effective drug delivery systems for brain.

Liu K., Fan Q., Qiao Z., Zhang Z., Zhang Y., Chen Z., Ma H., He Z., Miao Z., Huo J., Xin D., Guo J., Gao C.

Xu L., Zhang Y., Wang D., Ren Q., Wang Y., Zang Z., Guo A., Guo J., Wang L., Wang R., Liu Y.

AbstractMacrophages are key innate immune cells in the muscle environment of sarcopenia patients, significantly influencing muscle stem cell (MuSC) proliferation and differentiation. However, prolonged activation of macrophages can hinder muscle recovery. In this study, it synthesizes lipoic acid‐modified gold nanoparticles (LA‐Au NPs) of varying sizes to evaluate their biocompatibility and immunomodulatory effects. The findings demonstrate that LA‐Au NPs exhibit excellent biocompatibility with macrophages and promoted M2 polarization in a size‐dependent manner. Mechanistically, LA‐Au NPs facilitated metabolic reprogramming in macrophages by enhancing lysosomal autophagy and mitochondrial oxidative phosphorylation. Furthermore, macrophages are shown to chemotax toward MuSCs, regulating their proliferation via the chemokine system, inhibiting MuSC apoptosis, and enhancing differentiation under inflammatory conditions. In vivo studies have confirmed the safety and efficacy of LA‐Au NPs in sarcopenia mice. To further enhance the effectiveness of LA‐Au NPs, it investigates a delivery strategy that involves preconditioning macrophages with LA‐Au NPs (Mac@Au NPs). Compared to the direct injection of LA‐Au NPs, Mac@Au NPs demonstrate significantly greater benefits for muscle repair. This highlights the potential of macrophage therapy as a promising strategy for effective muscle regeneration and therapeutic intervention in sarcopenia.

Lee J.W., Lee J., Lee J., Kim D., Hong W., Lee J., Song M., Kang H.

AbstractPhotothermal neuromodulation, a rapidly advancing technique in neuroscience, has been introduced as an incredibly versatile platform for the in‐depth study of neural electrophysiological signals and the development of treatments for various neurological disorders. Particularly, nanomaterial‐based photothermal neuromodulation technologies have advantages compared to optogenetic stimulation methods, such as non‐genetic modification, minimally invasive, and reduced immune response. Photothermal neuromodulation research has introduced various nanomaterials and stimulation methods to regulate thermosensitive ion channels or modify cell membrane capacitance, enabling excitation and inhibition of neural activity. Recent advances in nanomaterials have significantly improved the precision and efficiency of photothermal neuromodulation, expanding its potential applications in neuroscience research. In the photothermal neuromodulation studies, different temperature measurement methods have been used but do not satisfy all the requirements necessary to analyze this phenomenon. An ideal temperature sensor for a photothermal neuromodulation study must have high transparency, high thermal sensitivity, and high spatial and temporal resolution. This review aims to cover the current status of thermally induced neuromodulation studies and the transparent temperature sensing methodologies that can be used for photothermal neuromodulation.

Ahmad I., Khan S.A., Jan R.

Du J., Xu H., Zhu X., Long K., Lang J., Jiang L., Xiong E., Yang R., Liu J.

AbstractWhile Au−S bonds have been widely applied in preparing gold nanoparticle (AuNP) bioconjugates for biosensing, cell imaging, and biomedical research, biothiols in complex biological environments can seriously interfere with the stability of the conjugates due to ligand exchange. Herein, we communicate a robust and fast strategy for constructing peptide‐functionalized AuNP conjugates (PFCs) using the Au−C≡C bond, which can be completed within two minutes. The resulting Au−C≡C PFCs exhibited better stability and resistance to biothiols than the corresponding Au−S PFCs, and also demonstrated excellent stability in high salt concentration, a wide range of pH values, and varying temperatures. The mechanism of Au−C≡C conjugation was confirmed using molecular dynamics simulation and X‐ray photoelectron spectroscopy (XPS). The Au−C≡C PFCs significantly improved the signal fidelity in an intracellular caspase imaging assay. Overall, the developed strategy provides a promising approach for constructing AuNP nanoprobes, allowing reliable detection and broadening the potential for diverse biological applications.

Du J., Xu H., Zhu X., Long K., Lang J., Jiang L., Xiong E., Yang R., Liu J.

AbstractWhile Au−S bonds have been widely applied in preparing gold nanoparticle (AuNP) bioconjugates for biosensing, cell imaging, and biomedical research, biothiols in complex biological environments can seriously interfere with the stability of the conjugates due to ligand exchange. Herein, we communicate a robust and fast strategy for constructing peptide‐functionalized AuNP conjugates (PFCs) using the Au−C≡C bond, which can be completed within two minutes. The resulting Au−C≡C PFCs exhibited better stability and resistance to biothiols than the corresponding Au−S PFCs, and also demonstrated excellent stability in high salt concentration, a wide range of pH values, and varying temperatures. The mechanism of Au−C≡C conjugation was confirmed using molecular dynamics simulation and X‐ray photoelectron spectroscopy (XPS). The Au−C≡C PFCs significantly improved the signal fidelity in an intracellular caspase imaging assay. Overall, the developed strategy provides a promising approach for constructing AuNP nanoprobes, allowing reliable detection and broadening the potential for diverse biological applications.

Tavakkoli Yaraki M., Aarti A., Zenaidee M.A., Chen D., Shen C., Li Q., Venkatesan K., Wang Y.

AbstractSynthesis of new nanomaterials with unique optical properties is of great importance in different fields such as energy, material science, and biomedicine. Here, for the first time, we report the synthesis of the emissive osmium nanoclusters (OsNCs) using bovine serum albumin (BSA) as template and sodium borohydride as strong reducing agent. The as‐synthesized emissive OsNCs had only 31 atoms, with deep‐blue color emission with an emission maximum at 415 nm and a photoluminescence quantum yield (PLQY) of 2.5 %. The fluorescence emission of OsNCs could be attributed to the smaller number of atoms (31) in the as‐synthesized OsNCs in this work. The optical characterization of the emissive OsNCs revealed that the fluorescence intensity was more sensitive to pH than with temperature of the solution. When pH was increased from 1–12, there was 6‐fold increase in the emission intensity. We believe that the presented synthesis route as well as the results of this work could open new avenues to further investigate the OsNCs as new emissive nanomaterials and their potential applications in biomedical and energy fields.

Pan S., Luo P., Huang Q., Xue J., Tian X., Xu B., Wu J., Chen J., Xie J., Yang N., Zhang X., Tian Z., Liu G.

Mahdi M.M., Salim E.T., Obaid A.S.

Niobium oxide (Nb₂O₅), a promising semiconductor, has attracted significant attention for its distinctive optical and electronic properties. This study reports the synthesis of Au@Nb₂O₅ core–shell nanostructures using pulsed laser ablation in liquid. The structural characterization confirms the formation of orthorhombic T-Nb₂O₅, as verified by XRD analysis. The optical band gap of the Au@Nb₂O₅ nanostructures is tunable, ranging from 2.27 to 2.18 eV. Morphological studies using FE-SEM and TEM reveal that laser fluence plays a critical role, with particle size and shell thickness increasing at higher laser energies. Photoluminescence measurements show a broad visible emission (455–480 nm), highlighting the potential for tuning optical properties through laser parameters. Furthermore, the design and analysis of an Au@Nb₂O₅/Si heterojunction photodetector are presented, showcasing its suitability for advanced optoelectronic applications.

Shahmoradi S., Imani M., Ellioun K., Janghorbani A., Ramezani Farani M., Yazdian F., Mostafavi E., Zare I.

Mohaghegh N., Ahari A., Abbasgholizadeh R., Ramezani Farani M., Hassani Najafabadi A., Zare I., Mostafavi E.

Birge G., Koyuncu Zeybek D.

Herein, a label-free electrochemical leptin immunosensor was demonstrated. The sensing platform consists of the immobilizing of the anti-leptin antibody on a glassy carbon electrode (GCE) modified with cobalt iron oxide (CoFe2O4) nanoparticles, chitosan (CHI), and gold nanoparticles (AuNPs). A simple and rapid leptin determination was achieved by measuring the change of current response in a redox probe solution before and after the immunocomplex formation. SEM examined the surface morphologies of the prepared electrodes. The electrochemical performance of the leptin immunosensor was commented on via EIS, CV, and DPV. Under optimized circumstances, a linear response was found between the current peaks acquired from DPV and the logarithm concentration of leptin in the range of 1─4000 ng mL-1 with a detection limit (LOD) of 0.1 ng mL-1. The subjected immunosensor demonstrated satisfactory reproducibility.

Azarian M., Farani M.R., Cho W.C., Asgharzadeh F., Yang Y., Binabaj M.M., Tambuwala M.M., Farahani N., Hushmandi K., Huh Y.S.

Farshid S., Mofazali P., Samadi A., Babaeizad A.

Hajebi S., Chamanara M., Nasiri S.S., Ghasri M., Mouraki A., Heidari R., Nourmohammadi A.

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.