Emerging advances in nano-biomaterial assisted amyloid beta chimeric antigen receptor macrophages (CAR-M) therapy: reducing plaque burden in Alzheimer's disease

Alzheimer's disease is the most common form, accounting for 60-70% of 55 million dementia cases. Even though the precise pathophysiology of AD is not completely understood, clinical trials focused on antibodies targeting aggregated forms of β amyloid (Aβ) have demonstrated that reducing amyloid plaques can arrest cognitive decline in patients in the early stages of AD. In this study, we provide an overview of current research and innovations for controlled release from nano-biomaterial-assisted chimeric antigen receptor macrophage (CAR-M) therapeutic strategies targeted at AD. Nano-bio materials, such as iron-oxide nanoparticles (IONPs), can be made selectively (Hp-Hb/mannose) to bind and take up Aβ plaques like CAR-M cells. By using nano-bio materials, both the delivery and stability of CAR-M cells in brain tissue can be improved to overcome the barriers of the BBB and enhance therapeutic effects. By enhancing the targeting capabilities and stability of CAR-M cells, mRNA-loaded nano-biomaterials can significantly improve the efficacy of immunotherapy for plaque reduction in AD. This novel strategy holds promise for translating preclinical successes into clinical applications, potentially revolutionising the management of AD.

Presence of nano-sized mercury-containing particles in seafoods, and an estimate of dietary exposure

The toxicity of nano-sized particles of mercury (NP-Hg), which are thought to be generated during the detoxification of methyl mercury (MeHg), may differ from that of MeHg, elemental Hg (Hg⁰), and inorganic Hg (I-Hg). From a human health perspective, it is important to evaluate the presence of NP-Hg in seafoods. We investigated the in vivo formation of NP-Hg in fish and shellfish, which are the main sources of Hg exposure in humans. NP-Hg was measured in 90 fish samples with single-particle inductively coupled plasma mass spectrometry (spICP-MS) after enzyme degradation with pancreatin and lipase. In addition to NP-Hg, total Hg (T-Hg), MeHg, and selenium (Se) concentrations were evaluated. Transient Hg signals were detected as nanoparticles from almost all samples by using spICP-MS. Higher particle number concentrations (C_PN) were observed in the tuna-swordfish group than in the shellfish group (17.7 × 10⁷ vs. 1.2 × 10⁶ particles/g, respectively). Although the C_PN and maximum particle mass increased significantly with increasing T-Hg concentration, the increase in C_PN was greater than those in maximum particle mass. Assuming that the NP-Hg detected was HgSe (tiemannite) and spherical based on previous reports, the maximum particle diameter was estimated to be 89 nm. The mean dietary exposures to NP-Hg, T-Hg, and MeHg were estimated to be 0.067, 5.75, and 5.32 μg/person per day, respectively. Generation of NP-Hg was inferred to be widespread in marine animals, with a preferential increase in the number of particles rather than an increase in particle size. The mean dietary exposure to NP-Hg in Japanese people was estimated to be 1.2 ng/kg body weight (BW) per day. Compared to PTWI of 4 μg/kg BW per week (0.57 μg/kg BW per day) derived by JECFA (2011), the health risk from redissolved I-Hg from NP-Hg is small.

Easy, Fast, Selective, and Simultaneous Separation of Hg(II) and Oil via Loofah-Sponge-Inspired Hierarchically Porous Membranes

In this work, Cu2Se/Cu membranes (CSMs) of hierarchical pores were fabricated via chemical dissolution of Cu and Se followed by redeposition of cuprous selenide (Cu2Se) on copper membranes (CMs), and applied for adsorption/removal/separation of Hg(II) among a variety of interfering metal ions. The CSM demonstrates the best comprehensive performance among previous Hg(II) adsorption membranes, having high selectivity (KHg/M = 2.9 × 104-3.0 × 105), high efficiency (>99%, 5 s to 3 min), high adsorption capacity (505 mg/g), and high flux (2.0 × 106 L m-2 h-1). Meanwhile, effects of Hg(II) concentration, flow rate, and the number of membrane layers and adsorption cycles were also investigated on the removal of Hg(II). Moreover, a Cu2Se/Cu membrane-plasma (CSM-p) with superhydrophilicity/underwater superoleophobicity was prepared on the basis of CSM, and simultaneous removal of Hg(II) and oil was realized by using CSM and CSM-p in combination. This work not only provides a new reference for design of highly selective, efficient metal ion adsorption/enrichment/separation materials but also presents a novel approach to the removal/enrichment/separation of multiple complex contaminants by the combination of different functional membranes.

Distributions of mercury and selenium in rats ingesting mercury selenide nanoparticles

Mercury (Hg) is one of the most toxic environmental pollutants, and is biocondensed via the food chain. Selenium (Se) is an essential element that possesses an antagonistic property towards Hg in vivo. The antagonistic property is explained by the assumption that Hg and Se directly interact to form HgSe nanoparticles (HgSe NPs) in organs. It is presumed that the toxic effects of HgSe NPs are lower than that of ionic Hg; however, no precise evaluation has been conducted so far. In the present study, we evaluated the distribution of HgSe NPs ingested in Se-deficient rats. The recovery of serum selenoproteins from a deficient level was not observed in rats orally administered HgSe NPs. In addition, the excretion of Hg and Se via urine was not observed. Interestingly, the biosynthesis of selenoproteins and urinary selenometabolites would have required the production of selenide through the degradation of HgSe NPs. Therefore, it seems that selenide and Hg are not released from HgSe NPs in vivo. The administration of HgSe NPs did not increase Hg and Se concentrations in organs, and almost all HgSe NPs were recovered in feces, indicating no or low bioaccessibility of HgSe NPs even in Se-deficient rats. These results suggest that HgSe NPs are biologically inert and do not become a secondary environmental pollutant of Hg.

Analyzing the surface of functional nanomaterials-how to quantify the total and derivatizable number of functional groups and ligands

Functional nanomaterials (NM) of different size, shape, chemical composition, and surface chemistry are of increasing relevance for many key technologies of the twenty-first century. This includes polymer and silica or silica-coated nanoparticles (NP) with covalently bound surface groups, semiconductor quantum dots (QD), metal and metal oxide NP, and lanthanide-based NP with coordinatively or electrostatically bound ligands, as well as surface-coated nanostructures like micellar encapsulated NP. The surface chemistry can significantly affect the physicochemical properties of NM, their charge, their processability and performance, as well as their impact on human health and the environment. Thus, analytical methods for the characterization of NM surface chemistry regarding chemical identification, quantification, and accessibility of functional groups (FG) and surface ligands bearing such FG are of increasing importance for quality control of NM synthesis up to nanosafety. Here, we provide an overview of analytical methods for FG analysis and quantification with special emphasis on bioanalytically relevant FG broadly utilized for the covalent attachment of biomolecules like proteins, peptides, and oligonucleotides and address method- and material-related challenges and limitations. Analytical techniques reviewed include electrochemical titration methods, optical assays, nuclear magnetic resonance and vibrational spectroscopy, as well as X-ray based and thermal analysis methods, covering the last 5-10 years. Criteria for method classification and evaluation include the need for a signal-generating label, provision of either the total or derivatizable number of FG, need for expensive instrumentation, and suitability for process and production control during NM synthesis and functionalization.

Connecting Cation Exchange and Metal Deposition Outcomes via Hume-Rothery-Like Design Rules Using Copper Selenide Nanoparticles

Heterogenous nanomaterials containing various inorganic phases have far-reaching impacts both from the physical phenomena they reveal and the technologies they enable. While the variety and impact of these materials has been demonstrated in many reports, there is critical ambiguity in the factors that lead to major bifurcations in developing these heterostructures, for example, the formation of either mixed metal semiconductors or segregated metal-semiconductor phases. Here, we compare outcomes of independently introducing 5 different metal cations (Au³⁺, Ag⁺, Hg²⁺, Pd²⁺, and Pt²⁺) to antifluorite copper selenide (Cu_2-xSe) nanoparticles (diameter = 52 ± 5 nm). This suite of metal cations allowed us to control for and evaluate a variety of potentially competing intrinsic system parameters including metal cation size, valency, and reduction potential as well as lattice volume change, lattice formation energy, and lattice mismatch. Upon secondary metal addition, we determined that the transformation of a cubic Cu_2-xSe lattice will occur via cation exchange reaction when the change in symmetry to the resulting metal selenide phase(s) preserves mutually orthogonal lattice vectors. However, if the new lattice symmetry would be disrupted further, metal deposition is the likely outcome of secondary metal cation addition, forming metal-semiconductor heterostructures. These results suggest a synthesis design rule that relies on an intrinsic property of the material, not the reaction pathway, and indicates that more such factors may be found in other particle and synthetic systems.

Nearly Monodisperse Copper Selenide Nanoparticles for Recognition, Enrichment, and Sensing of Mercury Ions

In the current work, Cu(I)_1.28Cu(II)_0.36Se nanoparticles were synthesized via a simple procedure and were applied for the first time for recognition, adsorption, enrichment, and detection of Hg(II) ions. The experimental results show that 99.9% Hg(II) could be adsorbed by Cu(I)_1.28Cu(II)_0.36Se nanoparticles within just 30 s, and the Hg(II) concentration could be lowered down to a super-low level of 0.01 ppb. Cu(I)_1.28Cu(II)_0.36Se nanoparticles also demonstrate high selectivity to Hg(II) and Ag(I) among nine representative metal ions. The enrichment experiments show that Hg(II) of ultratrace concentration could be enriched significantly by Cu(I)_1.28Cu(II)_0.36Se nanoparticles, and thus, the detection limit of Hg(II) based on inductively coupled plasma emission spectroscopy-mass spectrometry would be pushed down by 2 orders of magnitude. These outstanding features of Cu(I)_1.28Cu(II)_0.36Se nanoparticles could be well accounted for in terms of the solubility product principle and the high affinity between selenium and mercury. Cu(I)_1.28Cu(II)_0.36Se nanoparticles were also found to have peroxidase-like activity, which could be inhibited by Hg(II) but not by Ag(I). This unique characteristic coupled with the solubility product principle successfully allows recognition and detection of Hg(II) even in the presence of Ag(I), which has a similar pK_sp to Hg(II). As a result, the qualitative and quantitative analyses of Hg(II) could be performed by the naked eye and UV-visible spectroscopy, respectively. The current results indicate that Cu(I)_1.28Cu(II)_0.36Se nanoparticles not only have great potential in various aspects of dealing with Hg(II) pollution but would also shed light on discovering new nanomaterials to address other heavy metal ions.

Nanoparticles as Emerging Labels in Electrochemical Immunosensors

This review shows recent trends in the use of nanoparticles as labels for electrochemical immunosensing applications. Some general considerations on the principles of both the direct detection based on redox properties and indirect detection through electrocatalytic properties, before focusing on the applications for mainly proteins detection, are given. Emerging use as blocking tags in nanochannels-based immunosensing systems is also covered in this review. Finally, aspects related to the analytical performance of the developed devices together with prospects for future improvements and applications are discussed.

Simple and rapid electrochemical quantification of water-stabilized HgSe nanoparticles of great concern in environmental studies

The sensitive monitoring of mercury (II) selenide nanoparticles (HgSe NPs) is of great potential relevance in environmental studies, since such NPs are believed to be the ultimate metabolic product of the lifesaving mechanism pathway of Hg detoxification in biological systems. In this context, we take advantage of using gold-nanostructured screen-printed carbon electrodes (SPCE-Au) for the rapid, simple and sensitive electrochemical quantification of engineered water-stable HgSe NPs, as an advantageous alternative to conventional elemental analysis techniques. HgSe NPs are first treated in an optimized oxidative/acidic medium for Hg²⁺ release, followed by sensitive electrochemical detection by anodic stripping voltammetry (ASV). To the best of our knowledge, this is the first time that water-stable HgSe NPs are quantified using electrochemical techniques. The low limit of detection achieved (3.86 × 10⁷ HgSe NPs/mL) together with the excellent repeatability (RSD: 3%), reproducibility (RSD: 5%) and trueness (relative error: 10%), the good performance in real sea water samples (recoveries of the analytical signal higher than 90%) and the simplicity/low cost of analysis make our method an ideal candidate for HgSe NPs monitoring in future environmental studies.

Quantitative Assessment of Individual Populations Present in Nanoparticle-Antibody Conjugate Mixtures Using AF4-ICP-MS/MS

A current remaining challenge in nanotechnology is the fast and reliable determination of the ratios between engineered nanoparticles and the species attached to their surface after chemical functionalization. The approach proposed herein based on the online coupling of asymmetric flow field-flow fractionation (AF4) with inductively coupled plasma-tandem mass spectrometry (ICP-MS/MS) allows for the first time the direct determination of such ratios in CdSe/ZnS core-shell quantum dot:rat monoclonal IgG2a antibody (QD:Ab) conjugate mixtures in a single run without any previous sample preparation (i.e., derivatization). AF4 provides full recovery and adequate resolution of the resulting bioconjugate from the excess of nanoparticles and proteins used in the different bioconjugation mixtures (1:1, 2:1, and 3:1 QD:Ab molar ratios were assessed). The point-by-point determination by ICP-MS/MS of the metal to sulfur ratios along the bioconjugate fractographic peak allowed disclosing the mixture of the different species in the bioconjugated sample, providing not only the limits of the range of QD:Ab ratios in the different bioconjugate species resulting after functionalization but also a good estimation of their individual relative abundance in the mixture. Interestingly, a wide variety of compositions were observed for the different bioconjugate mixtures studied (QD:Ab molar ratios ranging from 0.27 to 4.6). The resulting weighted QD:Ab ratio computed in this way for each bioconjugate peak matches well with both the global (average) QD:Ab ratio experimentally obtained by the simpler peak area ratio computation and the theoretical QD:Ab molar ratios assayed, which internally validates the procedure developed.