Sarcoma cell-specific radiation sensitization by titanate scrolled nanosheets: insights from physicochemical analysis and transcriptomic profiling.

This study aimed to explore the potential of metal oxides such as Titanate Scrolled Nanosheets (TNs) in improving the radiosensitivity of sarcoma cell lines. Enhancing the response of cancer cells to radiation therapy is crucial, and one promising approach involves utilizing metal oxide nanoparticles. We focused on the impact of exposing two human sarcoma cell lines to both TNs and ionizing radiation (IR). Our research was prompted by previous in vitro toxicity assessments, revealing a correlation between TNs' toxicity and alterations in intracellular calcium homeostasis. A hydrothermal process using titanium dioxide powder in an alkaline solution produced the TNs. Our study quantified the intracellular content of TNs and analyzed their impact on radiation-induced responses. This assessment encompassed PIXE analysis, cell proliferation, and transcriptomic analysis. We observed that sarcoma cells internalized TNs, causing alterations in intracellular calcium homeostasis. We also found that irradiation influence intracellular calcium levels. Transcriptomic analysis revealed marked disparities in the gene expression patterns between the two sarcoma cell lines, suggesting a potential cell-line-dependent nano-sensitization to IR. These results significantly advance our comprehension of the interplay between TNs, IR, and cancer cells, promising potential enhancement of radiation therapy efficiency.

Highly Stable Low-Strain Flexible Sensors Based on Gold Nanoparticles/Silica Nanohelices.

Flexible strain sensors based on nanoparticle (NP) arrays show great potential for future applications such as electronic skin, flexible touchscreens, healthcare sensors, and robotics. However, even though these sensors can exhibit high sensitivity, they are usually not very stable under mechanical cycling and often exhibit large hysteresis, making them unsuitable for practical applications. In this work, strain sensors based on silica nanohelix (NH) arrays grafted with gold nanoparticles (AuNPs) can overcome these critical aspects. These 10 nm AuNPs are functionalized with mercaptopropionic acid (MPA) and different ratios of thiol-polyethylene glycol-carboxylic acid (HS-PEG7-COOH) to optimize the colloidal stability of the resulting NH@AuNPs nanocomposite suspensions, control their aggregation state, and tune the thickness of the insulating layer. They are then grafted covalently onto the surface of the NHs by chemical coupling. These nanomaterials exhibit a well-defined arrangement of AuNPs, which follows the helicity of the silica template. The modified NHs are then aligned by dielectrophoresis (DEP) between interdigitated electrodes on a flexible substrate. The flexibility, stability, and especially sensitivity of these sensors are then characterized by electromechanical measurements and scanning electron microscopy observations. These strain sensors based on NH@AuNPs nanocomposites are much more stable than those containing only nanoparticles and exhibit significantly reduced hysteresis and high sensitivity at very slight strains. They can retain their sensitivity even after 2 million consecutive cycles with virtually unchanged responsiveness. These improved performances come from their mechanical stability and the use of nanohelices as stable mechanical templates.

Chronic maternal exposure to titanium dioxide nanoparticles alters breathing in newborn offspring.

BACKGROUND: Over the last two decades, nanotechnologies and the use of nanoparticles represent one of the greatest technological advances in many fields of human activity. Particles of titanium dioxide (TiO2) are one of the nanomaterials most frequently found in everyday consumer products. But, due in particular to their extremely small size, TiO2 nanoparticles (NPs) are prone to cross biological barriers and potentially lead to adverse health effects. The presence of TiO2 NPs found in human placentae and in the infant meconium has indicated unequivocally the capacity for a materno-fetal transfer of this nanomaterial. Although chronic exposure to TiO2 NPs during pregnancy is known to induce offspring cognitive deficits associated with neurotoxicity, the impact of a gestational exposure on a vital motor function such as respiration, whose functional emergence occurs during fetal development, remains unknown. RESULTS: Using in vivo whole-body plethysmographic recordings from neonatal mice, we show that a chronic exposure to TiO2 NPs during pregnancy alters the respiratory activity of offspring, characterized by an abnormally elevated rate of breathing. Correspondingly, using ex vivo electrophysiological recordings performed on isolated brainstem-spinal cord preparations of newborn mice and medullary slice preparations containing specific nuclei controlling breathing frequency, we show that the spontaneously generated respiratory-related rhythm is significantly and abnormally accelerated in animals prenatally exposed to TiO2 NPs. Moreover, such a chronic prenatal exposure was found to impair the capacity of respiratory neural circuitry to effectively adjust breathing rates in response to excitatory environmental stimuli such as an increase in ambient temperature. CONCLUSIONS: Our findings thus demonstrate that a maternal exposure to TiO2 NPs during pregnancy affects the normal development and operation of the respiratory centers in progeny.

A Geant4 simulation of X-ray emission for three-dimensional proton imaging of microscopic samples.

PURPOSE: Proton computed microtomography is a technique that reveals the inner content of microscopic samples. The density distribution of the material (in g·cm-3) is obtained from proton transmission tomography (STIM: Scanning Transmission Ion Microscopy) and the element content from X-ray emission tomography (PIXE: Particle Induced X-ray Emission). A precise quantification of chemical elements is difficult for thick samples, because of the variations of X-ray production cross-sections and of X-ray absorption. Both phenomena are at the origin of an attenuation of the measured X-ray spectra, which leads to an underestimation of the element content. Our aim is to quantify the accuracy of a specific correction method that we designed for thick samples. METHODS: In this study, we describe how the 3D variations in the mass density were taken into account in the reconstruction code, in order to quantify the correction according to the position of the proton beam and the position and aperture angle of the X-ray detector. Moreover, we assess the accuracy of the reconstructed densities using Geant4 simulations on numerical phantoms, used as references. RESULTS: The correction process was successfully applied and led, for the largest regions of interest (little affected by partial volume effects), to an accuracy ≤ 4% for phosphorus (compared to about 40% discrepancy without correction). CONCLUSION: This study demonstrates the accuracy of the correction method implemented in the tomographic reconstruction code for thick samples. It also points out some advantages offered by Geant4 simulations: i) they produce projection data that are totally independent of the inversion method used for the image reconstruction; ii) one or more physical processes (X-ray absorption, proton energy loss) can be artificially turned off, in order to precisely quantify the effect of the different phenomena involved in the attenuation of X-ray spectra.

Hole Scavenging and Electron-Hole Pair Photoproduction Rate: Two Mandatory Key Factors to Control Single-Tip Au-CdSe/CdS Nanoheterodimers.

Metal/semiconductor hetero-nanostructures are now considered as benchmark functional nanomaterials for many light-driven applications. Using laser-driven photodeposition to control growth of gold nanodots (NDs) onto CdSe/CdS dot-in-rods (DRs), we show that the addition of a dedicated hole scavenger (MeOH) is the cornerstone to significantly reduce to less than 3.5% the multiple-site nucleation and 2.5% the rate of gold-free DRs. This means, from a synthetic point of view, that rates up to 90% of single-tip DRs can be reproducibly achieved. Moreover, by systematically varying this hole scavenger concentration and the Au/DRs ratio on the one hand, and the irradiation intensity and the time exposure on the other hand, we explain how gold deposition switches from multisite to single-tipped and how the growth and final size of the single photodeposited ND can be controlled. A model also establishes that the results obtained based on these different varying conditions can be merged onto a single "master behavior" that summarizes and predicts the single-tip gold ND growth onto the CdSe/CdS DRs. We eventually use data from the literature on growth of platinum NDs onto CdS nanorods by laser-deposition to extend our investigation to another metal of major interest and strengthen our modeling of single metallic ND growth onto II-VI semiconducting nanoparticles. This demonstrated strategy can raise a common methodology in the synthesis of single-tip semiconductor-metal hybrid nanoheterodimers (NHDs), leading to advanced nanoparticles architectures for applications in areas as different as photocatalysis, hydrogen production, photovoltaics, and light detection.

Design of Metal@Titanium Oxide Nano-heterodimers by Laser-Driven Photodeposition: Growth Mechanism and Modeling.

In order to circumvent the usual nucleation of randomly distributed tiny metallic dots photodeposited on TiO2 nanoparticles (NPs) induced by conventional UV lamps, we propose to synthesize well-controlled nanoheterodimers (NHDs) using lasers focused inside microfluidic reactors to strongly photoactivate redox reactions of active ions flowing along with nanoparticles in water solution. Since the flux of photons issued from a focused laser may be orders of magnitude higher than that reachable with classical lamps, the production of electron-hole pairs is tremendously increased, ensuring a large availability of carriers for the deposition and favoring the growth of a single metallic dot as compared to secondary nucleation events. We show that the growth of single silver or gold nanodots can be controlled by varying the beam intensity, the concentration of the metallic salt, and the flow velocity inside the microreactor. The confrontation to a build-in model of the metallic nanodot light-induced growth onto the surface of TiO2 NPs shows the emergence of a predictable "master behavior" on which individual growths obtained from various tested conditions do collapse. We also characterized the associated quantum yield. Eventually, we successfully confronted our model to growth data from the literature in the case of silver on TiO2 and gold on II-VI semiconducting NPs triggered by UV lamps. It shows that for the photosynthesis of NHDs the efficiency of the electron-hole pair production rate matters much more than the number of pairs produced and that the use of laser light can provide a photodeposition-based synthesis at the nanoscale.

Causal Inference Machine Learning Leads Original Experimental Discovery in CdSe/CdS Core/Shell Nanoparticles.

The synthesis of CdSe/CdS core/shell nanoparticles was revisited with the help of a causal inference machine learning framework. The tadpole morphology with 1-2 tails was experimentally discovered. The causal inference model revealed the causality between the oleic acid (OA), octadecylphosphonic acid (ODPA) ligands, and the detailed tail shape of the tadpole morphology. Further, with the identified causality, a neural network was provided to predict and directly lead to the original experimental discovery of new tadpole-shaped structures. An entropy-driven nucleation theory was developed to understand both the ligand and temperature dependent experimental data and the causal inference from the machine learning framework. This work provided a vivid example of how the artificial intelligence technology, including machine learning, could benefit the materials science research for the discovery.

Ligand-Induced Chirality in Asymmetric CdSe/CdS Nanostructures: A Close Look at Chiral Tadpoles.

Ligand-induced chirality in asymmetric CdSe/CdS core-shell nanocrystals (NCs) has been extensively applied in chiral biosensors, regioselective syntheses and assemblies, circularly polarized luminescence (CPL), and chiroptic-based devices due to their excellent physiochemical properties, such as the tunable quantum confinement effects, surface functionality, and chemical stability. Herein, we present CdSe/CdS NCs with various morphologies such as nanoflowers, tadpoles, and dot/rods (DRs) with chirality induced by surface chiral ligands. The observed circular dichroism (CD) and CPL activities are closely associated with the geometrical characteristics of the nanostructures, such as the shell thickness and the aspect ratio of the CdSe/CdS NCs. Furthermore, in situ observations of the growth of tadpoles with a single tail indicate that the CD response is mainly attributed to the CdS shell, which has a maximum tail length of ∼45 nm (approximately λ/10 of the incident light wavelength). On the other hand, the CPL activity is only related to the CdSe core, and the activity benefits from a thin CdS shell with a relatively high photoluminescence quantum yield (QY). Further theoretical models demonstrated the aspect-ratio-dependent g-factor and QY variations in these asymmetric nanostructures. These findings provide insights into not only the asymmetric synthesis of CdSe/CdS NCs, but also the rational design of CdSe/CdS nanostructures with tunable CD and CPL activities.

Microwave-Assisted and Metal-Induced Crystallization: A Rapid and Low Temperature Combination.

Here, we present a new crystallization process which, by combining microwaves and metal-induced devitrification, reduces both the time and the temperature of crystallization compared to other known methods. Titania crystallization initiates at a temperature as low as 125 °C within a few minutes of microwave radiation. Several cations induce this low-temperature crystallization, namely, Mn2+, Co2+, Ni2+, Al3+, Cu2+ and Zn2+. The crystallization mechanism is probed with electron microscopy, elemental mapping, single-particle inductively coupled plasma mass spectrometry, X-ray photoelectron spectroscopy, Auger electron spectroscopy, and scanning Auger mapping. These techniques show that the metal ion migration through the vitreous titania under microwave radiation occurs prior to crystallization. The crystalline particles are suspended in solution at the end of the treatment, avoiding particle aggregation and sintering. The crystalline suspensions are thus ready for processing into a material or employment in any other application. This combination of microwaves and metal-induced crystallization is applied here to TiO2, but we are investigating its application to other materials as an ecofriendly crystallization method.

Gd- and Eu-Loaded Iron Oxide@Silica Core-Shell Nanocomposites as Trimodal Contrast Agents for Magnetic Resonance Imaging and Optical Imaging.

Superparamagnetic maghemite core-porous silica shell nanoparticles, γ-Fe2O3@SiO2 (FS), with 50 nm diameter and a 10 nm core, impregnated with paramagnetic complexes b-Ln ([Ln(btfa)3(H2O)2]) (where btfa = 4,4,4-trifluoro-l-phenyl-1,3-butanedione and Ln = Gd, Eu, and Gd/Eu), performing as promising trimodal T1-T2 MRI and optical imaging contrast agents, are reported. These nanosystems exhibit a high dispersion stability in water and no observable cytotoxic effects, witnessed by intracellular ATP levels. The structure and superparamagnetic properties of the maghemite core nanocrystals are preserved upon imbedding the b-Ln complexes in the shell. Hela cells efficiently and swiftly internalize the NPs into the cytosol, with no observable cytotoxicity below a concentration of 62.5 µg mL-1. These nanosystems perform better than the free b-Gd complex as T1 (positive) contrast agents in cellular pellets, while their performance as T2 (negative) contrast agents is similar to the FS. Embedding of the b-Eu complex in the silica pores endows the nanoparticles with strong luminescence properties. The impregnation of gadolinium and europium complexes in a 1:1 ratio afforded a trimodal nanoplatform performing as a luminescent probe and a double T1 and T2 MRI contrast agent even more efficient than b-Gd used on its own, as observed in cell-labeled imaging experiments and MRI cell pellets.

A Geant4 simulation for three-dimensional proton imaging of microscopic samples.

Proton imaging can be carried out on microscopic samples by focusing the beam to a diameter ranging from a few micrometers down to a few tens of nanometers, depending on the required beam intensity and spatial resolution. Three-dimensional (3D) imaging by tomography is obtained from proton transmission (STIM: Scanning Transmission Ion Microscopy) and/or X-ray emission (PIXE: Particle Induced X-ray Emission). In these experiments, the samples are dehydrated for under vacuum analysis. In situ quantification of nanoparticles has been carried out at CENBG in the frame of nanotoxicology studies, on cells and small organisms used as biological models, especially on Caenorhabditis elegans (C. elegans) nematodes. Tomography experiments reveal the distribution of mass density and chemical content (in g.cm-3) within the analyzed volume. These density values are obtained using an inversion algorithm. To investigate the effect of this data reduction process, we defined different numerical phantoms, including a (dehydrated) C. elegans phantom whose geometry and density were derived from experimental data. A Monte Carlo simulation based on the Geant4 toolkit was developed. Using different simulation and reconstruction conditions, we compared the resulting tomographic images to the initial numerical reference phantom. A study of the relative error between the reconstructed and the reference images lead to the result that 20 protons per shot can be considered as an optimal number for 3D STIM imaging. Preliminary results for PIXE tomography are also presented, showing the interest of such numerical phantoms to produce reference data for future studies on X-ray signal attenuation in thick samples.

A facile route to synthesize CdSe/ZnS thick-shell quantum dots with precisely controlled green emission properties: towards QDs based LED applications.

In recent, the quantum yield (QY) and stability of green quantum dots (QDs) have been significantly improved. However, most of the progresses were achieved by using alloyed QDs, and the control of green emission QDs still remains challenging. Herein, we report a novel method for synthesizing thick-shell structure quantum dots (TSQDs) with saturated green-emitting where tri-n-octylphosphine (TOP) was used as both ligand and solvent to extract the redundant ions from the QDs surface and remove the lattice imperfections before any surface inorganic layer-by-layer coating. The as-prepared TSQDs demonstrate enhanced luminescent properties including high QY reaching up to 75%, full width at half maximum (FWHM) remaining close to 26 nm and tunable precise emission properties (532 nm), which can be utilized to perform 91% of the International Telecommunication Union (ITU) Recommendation BT. 2020 (Rec. 2020) for high definition and color gamut displays.

Chiral CdSe nanoplatelets as an ultrasensitive probe for lead ion sensing.

As opposed to traditional photoluminescence and ultra-violet based optical sensing, we present here a sensing system based on resolved optically active polarization with promising applications. It is based on the ultrathin CdSe nanoplatelets (NPLs) when modified with either l or d-cysteine molecules (l/d-cys) as bio-to-nano ligands. The chiral ligand transfers its chiroptical activity to the achiral nanoplatelets with an anisotropy factor of ∼10-4, which unlocks the chiral excitonic transitions and allows lead ion detection with a limit of detection (LOD) as low as 4.9 nM. Simulations and modelling based on time-dependent density functional theory (TD-DFT) reveal the chiral mechanism of l/d-cys capped CdSe NPLs. The presented CD-based sensing system illustrates an alternative possibility of using chiral CdSe NPLs as competitive chiral sensors for heavy metal ion detection.

Hydrothermal Transformation of Titanate Scrolled Nanosheets to Anatase over a Wide pH Range and Contribution of Triethanolamine and Oleic Acid to Control the Morphology.

Mild hydrothermal conditions used for the treatment of titanate scrolled nanosheets (SNSs) suspensions (140 °C, 72 h) resulted in a large variety of anatase TiO2 anisotropic nano-objects depending on the studied parameters: influence of the medium pH and the presence or not of structuring agents (SAs). The present work shows that such a hydrothermal treatment of the SNSs, whatever the pH, resulted in the formation of single-crystalline anatase nanoneedles (NNs) with a specific crystal-elongation direction and a pH-dependent morphological anisotropy with aspect ratios (ARs) from 1 to 8. The SNSs suspensions were prepared by the conventional ultrabasic treatment of TiO2 with NaOH, followed by washing with HNO3 to different pH values. The crystal size of the anatase TiO2 obtained from this hydrothermal treatment increased with the pH of the suspensions, from 15 nm nanoparticles (NPs; AR = 1) at pH 2.2 to 500 nm NNs (AR = 8) at a pH 10.8 with a long axis systematically along the anatase [001] direction. Triethanol amine and oleic acid were used as SAs. Their respective influence, when acting on their own, had little influence on the control of the size, shape, or polydispersity of the NNs. However, their concomitant use provided a much better control of not only the size and polydispersity, which was strongly reduced, but also on (i) the shape and morphology giving rise to a controlled access to well-defined nanorods as opposed to nanoneedles and (ii) the crystal phase purity eliminating the few percent brookite still visible in the X-ray diffraction patterns of samples prepared in SA-free conditions. This approach offers an on-demand control over the production of anatase morphologies with defined aspect ratios.

Plasmon-induced hot electron transfer in AgNW@TiO2@AuNPs nanostructures.

Compared to the limited absorption cross-section of conventional photoactive TiO2 nanoparticles (NPs), plasmonic metallic nanoparticles can efficiently convert photons from an extended spectrum range into energetic carriers because of the localized surface plasmon resonance (LSPR). Using these metal oxide semiconductors as shells for plasmonic nanoparticles (PNPs) that absorb visible light could extend their applications. The photophysics of such systems is performed using transient absorption measurements and steady extinction simulations and shows that the plasmonic energy transfer from the AgNWs core to the TiO2 shell results from a hot carrier injection process. Lifetimes obtained from photobleaching decay dynamics suggest that (i) the presence of gold nanoparticles (AuNPs) in AgNWs@TiO2@AuNPs systems can further promote the hot carrier transfer process via plasmonic coupling effects and (ii) the carrier dynamics is greatly affected by the shell thickness of TiO2. This result points out a definite direction to design appropriate nanostructures with tunable charge transfer processes toward photo-induced energy conversion applications.

Detrimental impact of silica nanoparticles on the nanomechanical properties of Escherichia coli, studied by AFM.

Despite great innovative and technological promises, nanoparticles (NPs) can ultimately exert an antibacterial activity by affecting the cell envelope integrity. This envelope, by conferring the cell its rigidity and protection, is intimately related to the mechanical behavior of the bacterial surface. Depending on their size, surface chemistry, shape, NPs can induce damages to the cell morphology and structure among others, and are therefore expected to alter the overall mechanical properties of bacteria. Although Atomic Force Microscopy (AFM) stands as a powerful tool to study biological systems, with high resolution and in near physiological environment, it has rarely been applied to investigate at the same time both morphological and mechanical degradations of bacteria upon NPs treatment. Consequently, this study aims at quantifying the impact of the silica NPs (SiO2-NPs) on the mechanical properties of E. coli cells after their exposure, and relating it to their toxic activity under a critical diameter. Cell elasticity was calculated by fitting the force curves with the Hertz model, and was correlated with the morphological study. SiO2-NPs of 100 nm diameter did not trigger any significant change in the Young modulus of E. coli, in agreement with the bacterial intact morphology and membrane structure. On the opposite, the 4 nm diameter SiO2-NPs did induce a significant decrease in E. coli Young modulus, mainly associated with the disorganization of lipopolysaccharides in the outer membrane and the permeation of the underlying peptidoglycan layer. The subsequent toxic behavior of these NPs is finally confirmed by the presence of membrane residues, due to cell lysis, exhibiting typical adhesion features.

Template-Directed Synthesis of Titania Nanocages with Four Tetrahedrally Arranged Open Windows.

Original titania nanocages are fabricated from sacrificial silica/polystyrene tetrapod-like templates. Here the template synthesis, titania deposition and nanocage development through polystyrene dissolution and subsequent silica etching are described. Discussion about the competitive deposition of titania on the biphasic templates is particularly emphasized. The morphology of the nanocages is investigated by TEM, STEM, EDX mapping and electron tomography.

In Situ Detection and Single Cell Quantification of Metal Oxide Nanoparticles Using Nuclear Microprobe Analysis.

Micro-analytical techniques based on chemical element imaging enable the localization and quantification of chemical composition at the cellular level. They offer new possibilities for the characterization of living systems and are particularly appropriate for detecting, localizing and quantifying the presence of metal oxide nanoparticles both in biological specimens and the environment. Indeed, these techniques all meet relevant requirements in terms of (i) sensitivity (from 1 up to 10 µg.g-1 of dry mass), (ii) micrometer range spatial resolution, and (iii) multi-element detection. Given these characteristics, microbeam chemical element imaging can powerfully complement routine imaging techniques such as optical and fluorescence microscopy. This protocol describes how to perform a nuclear microprobe analysis on cultured cells (U2OS) exposed to titanium dioxide nanoparticles. Cells must grow on and be exposed directly in a specially designed sample holder used on the optical microscope and in the nuclear microprobe analysis stages. Plunge-freeze cryogenic fixation of the samples preserves both the cellular organization and the chemical element distribution. Simultaneous nuclear microprobe analysis (scanning transmission ion microscopy, Rutherford backscattering spectrometry and particle induced X-ray emission) performed on the sample provides information about the cellular density, the local distribution of the chemical elements, as well as the cellular content of nanoparticles. There is a growing need for such analytical tools within biology, especially in the emerging context of Nanotoxicology and Nanomedicine for which our comprehension of the interactions between nanoparticles and biological samples must be deepened. In particular, as nuclear microprobe analysis does not require nanoparticles to be labelled, nanoparticle abundances are quantifiable down to the individual cell level in a cell population, independently of their surface state.

Probing the threshold of membrane damage and cytotoxicity effects induced by silica nanoparticles in Escherichia coli bacteria.

The engineering of nanomaterials, because of their specific properties, is increasingly being developed for commercial purposes over the past decades, to enhance diagnosis, cosmetics properties as well as sensing efficiency. However, the understanding of their fate and thus their interactions at the cellular level with bio-organisms remains elusive. Here, we investigate the size- and charge-dependence of the damages induced by silica nanoparticles (SiO2-NPs) on Gram-negative Escherichia coli bacteria. We show and quantify the existence of a NPs size threshold discriminating toxic and inert SiO2-NPs with a critical particle diameter (Φc) in the range 50nm-80nm. This particular threshold is identified at both the micrometer scale via viability tests through Colony Forming Units (CFU) counting, and the nanometer scale via atomic force microscopy (AFM). At this nanometer scale, AFM emphasizes the interaction between the cell membrane and SiO2-NPs from both topographic and mechanical points of view. For SiO2-NPs with Φ>Φc no change in E. coli morphology nor its outer membrane (OM) organization is observed unless the NPs are positively charged in which case reorganization and disruption of the OM are detected. Conversely, when Φ<Φc, E. coli exhibit unusual spherical shapes, partial collapse, even lysis, and OM reorganization.

GoldHelix: Gold Nanoparticles Forming 3D Helical Superstructures with Controlled Morphology and Strong Chiroptical Property.

Plasmonic nanoparticles, particularly gold nanoparticles (GNPs) hold a great potential as structural and functional building blocks for three-dimensional (3D) nanoarchitectures with specific optical applications. However, a rational control of their assembly into nanoscale superstructures with defined positioning and overall arrangement still remains challenging. Herein, we propose a solution to this challenge by using as building blocks: (1) nanometric silica helices with tunable handedness and sizes as a matrix and (2) GNPs with diameter varying from 4 to 10 nm to prepare a collection of helical GNPs superstructures (called Goldhelices hereafter). These nanomaterials exhibit well-defined arrangement of GNPs following the helicity of the silica template. Strong chiroptical activity is evidenced by circular dichroism (CD) spectroscopy at the wavelength of the surface plasmon resonance (SPR) of the GNPs with a anisotropy factor (g-factor) of the order of 1 × 10-4, i.e., 10-fold larger than what is typically reported in the literature. Such CD signals were simulated using a coupled dipole method which fit very well the experimental data. The measured signals are 1-2 orders of magnitude lower than the simulated signals, which is explained by the disordered GNPs grafting, the polydispersity of the GNPs, and the dimension of the nanohelices. These Goldhelices based on inorganic templates are much more robust than previously reported organic-based chiroptical nanostructures, making them good candidates for complex hierarchical organization, providing a promising approach for light management and benefits in applications such as circular polarizers, chiral metamaterials, or chiral sensing in the visible range.