Nanomaterials that Aid in the Diagnosis and Treatment of Alzheimer's Disease, Resolving Blood-Brain Barrier Crossing Ability

As a form of dementia, Alzheimer's disease (AD) suffers from no efficacious cure, yet AD treatment is still imperative, as it ameliorates the symptoms or prevents it from deteriorating or maintains the current status to the longest extent. The human brain is the most sensitive and complex organ in the body, which is protected by the blood-brain barrier (BBB). This yet induces the difficulty in curing AD as the drugs or nanomaterials that are much inhibited from reaching the lesion site. Thus, BBB crossing capability of drug delivery system remains a significant challenge in the development of neurological therapeutics. Fortunately, nano-enabled delivery systems possess promising potential to achieve multifunctional diagnostics/therapeutics against various targets of AD owing to their intriguing advantages of nanocarriers, including easy multifunctionalization on surfaces, high surface-to-volume ratio with large payloads, and potential ability to cross the BBB, making them capable of conquering the limitations of conventional drug candidates. This review, which focuses on the BBB crossing ability of the multifunctional nanomaterials in AD diagnosis and treatment, will provide an insightful vision that is conducive to the development of AD-related nanomaterials.

Oxidative stress modulating nanomaterials and their biochemical roles in nanomedicine

Many pathological conditions are predominantly associated with oxidative stress, arising from reactive oxygen species (ROS); therefore, the modulation of redox activities has been a key strategy to restore normal tissue functions. Current approaches involve establishing a favorable cellular redox environment through the administration of therapeutic drugs and redox-active nanomaterials (RANs). In particular, RANs not only provide a stable and reliable means of therapeutic delivery but also possess the capacity to finely tune various interconnected components, including radicals, enzymes, proteins, transcription factors, and metabolites. Here, we discuss the roles that engineered RANs play in a spectrum of pathological conditions, such as cancer, neurodegenerative diseases, infections, and inflammation. We visualize the dual functions of RANs as both generator and scavenger of ROS, emphasizing their profound impact on diverse cellular functions. The focus of this review is solely on inorganic redox-active nanomaterials (inorganic RANs). Additionally, we deliberate on the challenges associated with current RANs-based approaches and propose potential research directions for their future clinical translation.

Targeting Amyloids with Coated Nanoparticles: A Review on Potential Combinations of Nanoparticles and Bio-Compatible Coatings

Amyloidosis is the major cause of many neurodegenerative diseases, such as, Alzheimer's and Parkinson's where the misfolding and deposition of a previously functional protein make it inept for carrying out its function. The genesis of amyloid fibril formation and the strategies to inhibit it have been studied extensively, although some parts of this puzzle still remain unfathomable to date. Many classes of molecules have been explored as potential drugs in vitro, but their inability to work in vivo by crossing the blood-brain-barrier has made them an inadequate treatment option. In this regard, nanoparticles (NPs) have turned out to be an exciting alternative because they could overcome many drawbacks of previously studied molecules and provide advantages, such as, greater bioavailability of molecules and target-specific delivery of drugs. In this paper, we present an overview on several coated NPs which have shown promising efficiency in inhibiting fibril formation. A hundred and thirty papers published in the past two decades have been comprehensively reviewed, which majorly encompass NPs comprising different materials like gold, silver, iron-oxide, poly(lactic-co-glycolic acid), polymeric NP, etc., which are coated with various molecules of predominantly natural origin, such as different types of amino acids, peptides, curcumin, drugs, catechin, etc. We hope that this review will shed light on the advancement of symbiotic amalgamation of NPs with molecules from natural sources and will inspire further research on the tremendous therapeutic potential of these combinations for many amyloid-related diseases.

Metal Nanoparticles in Alzheimer's Disease

Nanotechnology has emerged in different fields of biomedical application, including lifestyle diseases like diabetes, hypertension, and chronic kidney disease, neurodegenerative diseases like Alzheimer's disease (AD), Parkinson's disease, and different types of cancers. Metal nanoparticles are one of the most used drug delivery systems due to the benefits of their enhanced physicochemical properties as compared to bulk metals. Neurodegenerative diseases are the second most cause affecting mortality worldwide after cancer. Hence, they require the most specific and targeted drug delivery systems for maximum therapeutic benefits. Metal nanoparticles are the preferred drug delivery system, possessing greater blood-brain barrier permeability, biocompatibility, and enhanced bioavailability. But some metal nanoparticles exhibit neurotoxic activity owing to their shape, size, surface charge, or surface modification. This review article has discussed the pathophysiology of AD. The neuroprotective mechanism of gold, silver, selenium, ruthenium, cerium oxide, zinc oxide, and iron oxide nanoparticles are discussed. Again, the neurotoxic mechanisms of gold, iron oxide, titanium dioxide, and cobalt oxide are also included. The neuroprotective and neurotoxic effects of nanoparticles targeted for treating AD are discussed elaborately. The review also focusses on the biocompatibility of metal nanoparticles for targeting the brain in treating AD. The clinical trials and the requirement to develop new drug delivery systems are critically analyzed. This review can show a path for the researchers involved in the brain-targeted drug delivery for AD.

Electrostatic assembly of gold nanoparticle and metal-organic framework nanoparticles attenuates amyloid β aggregate-mediated neurotoxicity

The deposition of amyloid β (Aβ) is a conventional pathological hallmark of Alzheimer's disease (AD). Consequently, the inhibition of Aβ aggregation combined with the disaggregation of Aβ fibrils is an important therapeutic method for AD treatment. In this study, a gold nanoparticle-decorated porous metal organic framework MIL-101(Fe) (AuNPs@PEG@MIL-101) was created as an Aβ inhibitor. The high positively charged MIL-101 induced a high number of Aβ₄₀ to be absorbed or aggregated on the surface of nanoparticles. In addition, AuNPs improved the surface property of MIL-101, causing it to uniformly bind Aβ monomers and Aβ fibrils. Thus, this framework can efficiently suppress extracellular Aβ monomer fibrillation and disrupt the preformed Aβ fibers. AuNPs@PEG@MIL-101 also decreases intracellular Aβ₄₀ aggregation and the amount of Aβ₄₀ immobilized on the cell membrane, thus protecting PC12 cells from Aβ₄₀-induced microtubular defects and cell membrane damage. In summary, AuNPs@PEG@MIL-101 shows great potential for application in AD therapy.

Multifunctional Selenium Nanoparticles with Different Surface Modifications Ameliorate Neuroinflammation through the Gut Microbiota-NLRP3 Inflammasome-Brain Axis in APP/PS1 Mice

Neuroinflammation plays a critical role in Alzheimer's disease (AD). However, it is still unknown if neuroinflammation can be effectively treated using selenium nanoparticles (SeNPs) with different surface modifications. In this study, SeNPs were coated with dihydromyricetin (DMY), a natural polyphenol, to obtain DMY@SeNPs. Given that DMY@SeNPs are unstable under physiological conditions, they were decorated step-by-step with chitosan (CS/DMY@SeNPs) and with the blood brain barrier (BBB) targeting peptide Tg (TGNYKALHPHNG) to yield Tg-CS/DMY@SeNPs, which significantly reduced the aggregation of Aβ and improved the anti-inflammatory effects of SeNPs in vitro. The mechanisms of CS/DMY@SeNPs and Tg-CS/DMY@SeNPs on regulating neuroinflammation are different. Only Tg-CS/DMY@SeNPs can cross the BBB; therefore, Tg-CS/DMY@SeNPs more successfully inhibited Aβ aggregation and reduced inflammatory cytokine secretion via the NF-κB pathway in the brain of APP/PS1 mice compared to CS/DMY@SeNPs. Furthermore, both types of nanoparticles, however, were able to repair the gut barrier and regulate the population of inflammatory-related gut microbiota such as Bifidobacterium, Dubosiella, and Desulfovibrio. Of note, the relative abundance of Gordonibacter was only enhanced by Tg-CS/DMY@SeNPs, thereby downregulating the protein expression of the NLRP3 inflammasome and the concentrations of serum inflammatory factors. This demonstrates that Tg-CS/DMY@SeNPs ameliorate neuroinflammation through the gut microbiota-NLRP3 inflammasome-brain axis. Overall, our data suggest that Tg-CS/DMY@SeNPs are an ideal drug candidate for AD treatment.

Electrochemical Strategy for Analyzing the Co-evolution of Cu2+ and •OH Levels at the Early Stages of Transgenic AD Mice

As more researchers have acknowledged that the aggregation of amyloid β (Aβ) peptides might only be a pathological phenomenon that appears during the course of Alzheimer's disease (AD), it is therefore of great significance to have a preclinical or an early clinical diagnosis. Cu²⁺ dyshomeostasis and oxidative stress, such as hydroxyl radical (^•OH), are found to be associated with peptide aggregations. However, we still do not know how the levels of Cu²⁺ and ^•OH are altered in the brain before massive Aβ plaques appear. Herein, we demonstrated the design and application of a sensitive electrochemical sensor to monitor Cu²⁺ and ^•OH simultaneously in one system without obvious cross-talk. The electrode was fabricated using black phosphorus-loaded Au (BP-Au) nanoparticles, which were then sequentially linked with DNA1, DNA2-labeled Au (Au-DNA2) nanoparticles, and methylene blue (MB). Cu²⁺ was first recognized and captured onto the sensor by BP with high selectivity and then produced a reduction current at around -0.01 V. The ^•OH quantification was established on the cleavage of the hybrid structure between DNA1 and BP-Au upon the appearance of ^•OH in the phosphate-buffered saline (PBS), leading to the depletion of the voltammetric response of MB around -0.25 V. Good linear correlations were obtained over concentrations of 0.5-127.5 μM for Cu²⁺ and 0.5-96.0 μM for ^•OH. Most importantly, the developed sensor was successfully applied to track the variations of the two species in brain tissues from APP/PS1 transgenic AD mice at the early stages before massive Aβ plaques appeared.

Recent Advances in Nanotheranostics for Treat-to-Target of Rheumatoid Arthritis

Early diagnosis, standardized treatment, and regular monitoring are the clinical treatment principle of rheumatoid arthritis (RA). The overarching principles and recommendations of treat-to-target (T2T) in RA advocate remission as the optimum aim, especially for patients with very early disease who are initiating therapy with anti-RA medications. However, traditional anti-RA drugs cannot selectively target the inflammatory areas and may cause serious side effects due to its short biological half-life and poor bioavailability. These limitations have significantly driven the research and application of nanomaterial-based drugs in theranostics of RA. Nanomedicines have appropriate sizes and easily modified surfaces which can enhance their biological compatibility and prolong circulation time of drug-loading systems in vivo. Traditional T2T regimens cannot evaluate the efficacy of drugs in real time, while clinical drug nanosizing can realize the integration of diagnosis and treatment of RA. This review bridges clinically proposed T2T concepts and nanomedicine in an integrated system for RA early-stage diagnosis and treatment. The most advanced progress in various nanodrug delivery systems for theranostics of RA is summarized, establishing a clear path and a new perspective for further optimization of T2T. Finally, the key facing challenges are discussed and prospects are addressed.

Conjugation of RTHLVFFARK to human lysozyme creates a potent multifunctional modulator for Cu2+-mediated amyloid β-protein aggregation and cytotoxicity

Conjugation of alkaline decapeptide (RTHLVFFARK) to lysozyme creates a potent multifunctional modulator (R-hLys) for Cu²⁺-mediated amyloid β-protein aggregation and cytotoxicity.

A comparative study of resveratrol and resveratrol-functional selenium nanoparticles: Inhibiting amyloid β aggregation and reactive oxygen species formation properties

Deposition of amyloid-β (Aβ) aggregates and formation of neurotoxic reactive oxygen species (ROS) are significant pathological signatures of Alzheimer's disease (AD). Resveratrol (Res) is an antioxidant with the potential to treat AD. However, the bioavailability and solubility of Res is very low and it cannot entirely inhibit Cu²⁺ -induced Aβ42 aggregation at low concentration. Herein, we combine the unique Aβ absorption property of selenium nanoparticles with the natural antioxidant agent Res to form Res@SeNPs. Our in vitro biological evaluation revealed that modification of Res with SeNPs provides a synergistic effect on Cu²⁺ -induced Aβ42 aggregation, ROS generation and, more importantly, protects PC12 cells from Aβ42-Cu²⁺ complexes-induced cell death. It is believed that SeNPs can improve the application of Res in AD treatment as Res@SeNPs is more efficient than Res in reducing Aβ42 toxicity in long-term use. © 2018 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 106A: 3034-3041, 2018.

Insulin adsorption onto zinc oxide nanoparticle mediates conformational rearrangement into amyloid-prone structure with enhanced cytotoxic propensity

BACKGROUND

Injection localized amyloidosis is one of the most prevalent disorders in type II diabetes mellitus (TIIDM) patients relying on insulin injections. Previous studies have reported that nanoparticles can play a role in the amyloidogenic process of proteins. Hence, the present study deals with the effect of zinc oxide nanoparticles (ZnONP) on the amyloidogenicity and cytotoxicity of insulin.

METHODS

ZnONP is synthesised and characterized using XRD, Zeta Sizer, UV-Visible spectroscope and TEM. The characterization is followed by ZnONP interaction with insulin, which is studied employing fluorescence spectroscopes, isothermal titration calorimetry and molecular dynamics simulations. The interaction leads insulin conformational rearrangement into amyloid-like fibril, which is studied using thioflavin T dye binding assay, circular dichroism spectroscopy and TEM, followed by cytotoxicity propensity using Alamar Blue dye reduction assay.

RESULTS

Insulin has very weak interaction with ZnONP interface. Insulin at studied concentration forms amorphous aggregates at physiological pH, whereas in presence of ZnONP interface amyloid-like fibrils are formed. While the amyloid-like fibrils are cytotoxic to MIN6 and THP-1 cell lines, insulin and ZnONP individual solutions and their fresh mixtures enhance the cells proliferation.

CONCLUSIONS

The presence of ZnONP interface enhances insulin fibrillation at physiological pH by providing a favourable template for the nucleation and growth of insulin amyloids.

GENERAL SIGNIFICANCE

The studied protein-nanoparticle system from protein conformational dynamics point of view throws caution over nanoparticle use in biological applications, especially in vivo applications, considering the amyloidosis a very slow but non-curable degenerative disease.

Sulfur Nanoparticles with Novel Morphologies Coupled with Brain-Targeting Peptides RVG as a New Type of Inhibitor Against Metal-Induced Aβ Aggregation

Functionalized nanomaterials, which have been applied widely to inhibit amyloid-β protein (Aβ) aggregation, show enormous potential in the field of prevention and treatment of Alzheimer's disease (AD). A significant body of data has demonstrated that the morphology and size of nanomaterials have remarkable effects on their biological behaviors. In this work, we proposed and designed three kinds of brain-targeting sulfur nanoparticles (RVG@Met@SNPs) with novel morphologies (volute-like, tadpole-like, and sphere-like) and investigated the effect of different RVG@Met@SNPs on Aβ-Cu²⁺ complex aggregation and their corresponding neurotoxicity. Among them, the sphere-like nanoparticles (RVG@Met@SS) exhibited the most effective inhibitory activity, due to their unique mini size effect, and they reduced 61.6% the Aβ-Cu²⁺ complex aggregation and increased 92.4% SH-SY5Y cell viability in a dose of 10 μg/mL. In vitro and in vivo, the abilities of different morphologies of RVG@Met@SNPs to cross the blood-brain barrier (BBB) and target brain parenchymal cells were significantly different. Moreover, improvements in learning disability and cognitive loss were shown in the transgenic AD mice model using the Morris water maze test after multiple doses of RVG@Met@SNPs treatment. In general, the purpose of this research is to develop a biological application of sulfur nanoparticles and to provide a novel functionalized nanomaterial to treat AD.

Polypeptide nano-Se targeting inflammation and theranostic rheumatoid arthritis by anti-angiogenic and NO activating AMPKα signaling pathway

Rheumatoid arthritis (RA) is a chronic autoimmune disease and there is a lack of effective treatments.

Redox-active nanomaterials for nanomedicine applications

Nanomedicine utilizes the remarkable properties of nanomaterials for the diagnosis, treatment, and prevention of disease. Many of these nanomaterials have been shown to have robust antioxidative properties, potentially functioning as strong scavengers of reactive oxygen species. Conversely, several nanomaterials have also been shown to promote the generation of reactive oxygen species, which may precipitate the onset of oxidative stress, a state that is thought to contribute to the development of a variety of adverse conditions. As such, the impacts of nanomaterials on biological entities are often associated with and influenced by their specific redox properties. In this review, we overview several classes of nanomaterials that have been or projected to be used across a wide range of biomedical applications, with discussion focusing on their unique redox properties. Nanomaterials examined include iron, cerium, and titanium metal oxide nanoparticles, gold, silver, and selenium nanoparticles, and various nanoscale carbon allotropes such as graphene, carbon nanotubes, fullerenes, and their derivatives/variations. Principal topics of discussion include the chemical mechanisms by which the nanomaterials directly interact with biological entities and the biological cascades that are thus indirectly impacted. Selected case studies highlighting the redox properties of nanomaterials and how they affect biological responses are used to exemplify the biologically-relevant redox mechanisms for each of the described nanomaterials.

Pompon-like RuNPs-Based Theranostic Nanocarrier System with Stable Photoacoustic Imaging Characteristic for Accurate Tumor Detection and Efficient Phototherapy Guidance

Even though numerous therapeutic methods exist for cancer treatment, many fail to achieve ideal outcomes or have severe side effects. Here, we describe a theranostic nanocarrier system with improved tumor vasculature detection and tumor margin quantification that increases the accuracy and guidance efficiency of phototherapy. Novel pompon-like RuNPs with superb photothermal properties and high encapsulation efficiency were first synthesized via the polyol reducing method. Based on these RuNPs, we then developed a multifunctional theranostic system, pRu-pNIPAM@RBT, composed of poly(N-isopropylacrylamide) as the thermal-response switch and of [Ru(bpy)₂(tip)]²⁺ as the photosensitizer of PDT and the contrast agent of biomedical imaging. We demonstrate that the pRu-pNIPAM@RBT can generate intracellular hyperthermia and reactive oxygen species (ROS) for simultaneous photothermal therapy (PTT) and photodynamic therapy (PDT) by laser activation. In contrast to other studies, our work highlights the integration of quantitative analysis of infrared thermal imaging and PA imaging data, which can distinguish between tumor and healthy tissues and guide the destructive but precise phototherapy and decrease nonspecific tissue injury. Considering the excellent in vivo antitumor phototherapeutic effects, this strategy may help preclinical researchers gain insight into theoretical as well as practical aspects of precision cancer therapy.

Dual-functional selenium nanoparticles bind to and inhibit amyloid β fiber formation in Alzheimer's disease

LPFFD/TGN modified SeNPs could cross the BBB and selectively bind to Aβ species. This binding might disrupted Aβ₄₀nucleation, and finally decrease Aβ₄₀fibrillation and their corresponding neurotoxicity in PC12 cells.

Gold nanoparticle-capped mesoporous silica-based H2O2-responsive controlled release system for Alzheimer's disease treatment

Metal ions promote Alzheimer's disease (AD) pathogenesis by accelerating amyloid-β (Aβ) aggregation and inducing formation of neurotoxic reactive oxygen species (ROS) such as hydrogen peroxide (H₂O₂). Although metal chelators can block these effects, their therapeutic potential is marred by their inability to cross the blood-brain barrier (BBB) and by their non-specific interactions with metal ions necessary for normal cellular processes, which could result in adverse side effects. To overcome these limitations, we created a novel gold nanoparticle-capped mesoporous silica (MSN-AuNPs) based H₂O₂-responsive controlled release system for targeted delivery of the metal chelator CQ. In this system, CQ is released only upon exposure to conditions in which H₂O₂ levels are high, such as those in Aβ plaques. The conjugation of AuNPs on the surface of MSN did not affect their ability to cross the BBB. The AuNPs also help in decrease the Aβ self-assembly, due to this, MSN-CQ-AuNPs were more efficient than MSN-CQ in inhibiting Cu²⁺-induced Aβ₄₀ aggregation. Furthermore, MSN-CQ-AuNPs reduced the cell membrane disruption, microtubular defects and ROS-mediated apoptosis induced by Aβ₄₀-Cu²⁺ complexes. The high BBB permeability, efficient anti-Aβ aggregation, and good biocompatibility of MSN-CQ-AuNPs, together with the specific conditions necessary for its release of CQ, demonstrate its potential for future biomedical applications.

STATEMENT OF SIGNIFICANCE

Due to the low ability to cross the blood-brain barrier (BBB) and non-specific interactions with metal ions necessary for normal cellular processes of metal chelator or Aβ inhibitors, we created a novel gold nanoparticle-capped mesoporous silica (MSN-AuNPs)-based H₂O₂-responsive controlled release system for targeted delivery of the metal chelator CQ and AuNPs (Aβ inhibitor). In this system, CQ and AuNPs are released only upon exposure to conditions in which H₂O₂ levels are high, such as those in Aβ plaques. The AuNPs on the surface of MSN also help in decrease the Aβ self-assembly, due to this, MSN-CQ-AuNPs were more efficient than MSN-CQ in inhibiting Cu²⁺-induced Aβ₄₀ aggregation. Furthermore, MSN-CQ-AuNPs reduced the cell membrane disruption, microtubular defects and ROS-mediated apoptosis induced by Aβ₄₀-Cu²⁺ complexes. Our data suggest that this controlled release system may have widespread application in the field of medicine for Alzheimer's disease.

Penetratin Peptide-Functionalized Gold Nanostars: Enhanced BBB Permeability and NIR Photothermal Treatment of Alzheimer's Disease Using Ultralow Irradiance

The structural changes of amyloid-beta (Aβ) from nontoxic monomers into neurotoxic aggregates are implicated with pathogenesis of Alzheimer's disease (AD). Over the past decades, weak disaggregation ability and low permeability to the blood-brain barrier (BBB) may be the main obstacles for major Aβ aggregation blockers. Here, we synthesized penetratin (Pen) peptide loaded poly(ethylene glycol) (PEG)-stabilized gold nanostars (AuNS) modified with ruthenium complex (Ru@Pen@PEG-AuNS), and Ru(II) complex as luminescent probes for tracking drug delivery. We revealed that Ru@Pen@PEG-AuNS could obviously inhibit the formation of Aβ fibrils as well as dissociate preformed fibrous Aβ under the irradiation of near-infrared (NIR) due to the NIR absorption characteristic of AuNS. More importantly, this novel design could be applied in medicine as an appropriate nanovehicle, being highly biocompatible and hemocompatible. In addition, Ru@Pen@PEG-AuNS had excellent neuroprotective effect on the Aβ-induced cellular toxicity by applying NIR irradiation. Meanwhile, Pen peptide could effectively improve the delivery of nanoparticles to the brain in vitro and in vivo, which overcame the major limitation of Aβ aggregation blockers. These consequences illustrated that the enhanced BBB permeability and efficient photothermolysis of Ru@Pen@PEG-AuNS are promising agents in AD therapy.

Improving the Anticancer Efficacy of Laminin Receptor-Specific Therapeutic Ruthenium Nanoparticles (RuBB-Loaded EGCG-RuNPs) via ROS-Dependent Apoptosis in SMMC-7721 Cells

Functionalization can promote the uptake of nanoparticles into cancer cells via receptor-mediated endocytosis, enabling them to exert their therapeutic effects. In this paper, epigallocatechin gallate (EGCG), which has a high binding affinity to 67 kDa laminin receptor (67LR) overexpressed in HCC cells, was employed in the present study to functionalized ruthenium nanoparticles (RuNPs) loaded with luminescent ruthenium complexes to achieve antiliver cancer efficacy. [Ru(bpy)2(4-B)] (ClO4)2·2H2O (RuBB)-loaded EGCG-RuNPs (bpy = 2,2'-bipyridine) showed small particle size with narrow distribution, better stability, and high selectivity between liver cancer and normal cells. The internalization of RuBB-loaded EGCG-RuNPs was inhibited by 67LR-blocking antibody or laminin, suggesting that 67LR-mediated endocytosis played an important role in the uptake into HCC cells. Moreover, transmission electron microscopy and confocal microscopic images showed that RuBB-loaded EGCG-RuNPs accumulated in the cytoplasm of SMMC-7721 cells. Furthermore, our results indicated that the EGCG-functionalized nanoparticles displayed enhanced anticancer effects in a target-specific manner. Concentrations of RuBB-loaded EGCG-RuNPs, nontoxic in normal L-02 cells, showed direct reactive oxygen species-dependent cytotoxic, pro-apoptotic, and anti-invasive effects in SMMC-7721 cells. Furthermore, in vivo animal study demonstrated that RuBB-loaded EGCG-RuNPs possessed high antitumor efficacy on tumor-bearing nude mice. It is encouraging to conclude that the multifunctional RuNPs may form the basis of new strategies on the treatment of liver cancer and other malignancies.

Green synthesis of Se/Ru alloy nanoparticles using gallic acid and evaluation of theiranti-invasive effects in HeLa cells

Methods for the synthesis of nanoparticles (NPs) for biomedical applications ideally involve the use of nontoxic reducing and capping agents, and more importantly, enable control over the shape and size of the particles. As such, we used gallic acid (GA) as both a reducing and a capping agent in a simple and "green" synthesis of stable Se/Rualloy NPs (GA-Se/RuNPs). The diameter and morphology of the Se/Ru alloy NPs were regulated by GA concentration, and the presence of Ru was found to be a key factor in regulating and controlling the size of GA-Se/RuNPs. Moreover, GA-Se/RuNPs suppressed HeLa cell proliferation through the induction of apoptosis at concentrations that were nontoxic in normal cells. Furthermore, GA-Se/RuNPs effectively inhibited migration and invasion in HeLa cells via the inhibition of MMP-2 and MMP-9 proteins. Our findings confirm that bimetallic (Se/Ru) NPs prepared via GA-mediated synthesis exhibit enhanced anticancer effects.

Bioactive SiO2@Ru nanoparticles for osteogenic differentiation of mesenchymal stem cells via activation of Akt signaling pathways

The surface chemistry of materials has an interactive influence on cell behavior.

Sialic acid (SA)-modified selenium nanoparticles coated with a high blood-brain barrier permeability peptide-B6 peptide for potential use in Alzheimer's disease

The blood-brain barrier (BBB) is a formidable gatekeeper toward exogenous substances, playing an important role in brain homeostasis and maintaining a healthy microenvironment for complex neuronal activities. However, it also greatly hinders drug permeability into the brain and limits the management of brain diseases. The development of new drugs that show improved transport across the BBB represents a promising strategy for Alzheimer's disease (AD) intervention. Whereas, previous study of receptor-mediated endogenous BBB transport systems has focused on a strategy of using transferrin to facilitate brain drug delivery system, a system that still suffers from limitations including synthesis procedure, stability and immunological response. In the present study, we synthetised sialic acid (SA)-modified selenium (Se) nanoparticles conjugated with an alternative peptide-B6 peptide (B6-SA-SeNPs, a synthetic selenoprotein analogue), which shows high permeability across the BBB and has the potential to serve as a novel nanomedicine for disease modification in AD. Laser-scanning confocal microscopy, flow cytometry analysis and inductively coupled plasma-atomic emission spectroscopy ICP-AES revealed high cellular uptake of B6-SA-SeNPs by cerebral endothelial cells (bEnd.3). The transport efficiency of B6-SA-SeNPs was evaluated in a Transwell experiment based on in vitro BBB model. It provided direct evidence for B6-SA-SeNPs crossing the BBB and being absorbed by PC12 cells. Moreover, inhibitory effects of B6-SA-SeNPs on amyloid-β peptide (Aβ) fibrillation could be demonstrated in PC12 cells and bEnd3 cells. B6-SA-SeNPs could not only effectively inhibit Aβ aggregation but could disaggregate preformed Aβ fibrils into non-toxic amorphous oligomers. These results suggested that B6-SA-SeNPs may provide a promising platform, particularly for the application of nanoparticles in the treatment of brain diseases.

STATEMENT OF SIGNIFICANCE

Alzheimer's disease (AD) is the world's most common form of dementia characterized by intracellular neurofibrillary tangles in the brain. Over the past decades, the blood-brain barrier (BBB) limits access of therapeutic or diagnostic agents into the brain, which greatly hinders the development of new drugs for treating AD. In this work, we evaluated the efficiency of B6-SA-SeNPs across BBB and investigated the interactions between B6-SA-SeNPs and amyloid-β peptide (Aβ). We confirm that B6-SA-SeNPs could provide a promising platform because of its high brain delivery efficiency, anti-amyloid properties and anti-oxidant properties, which may serve as a novel nanomedicine for the application in the treatment of brain diseases.

PEG modified graphene oxide loaded with EALYLV peptides for inhibiting the aggregation of hIAPP associated with type-2 diabetes

Human islet amyloid polypeptide (hIAPP) was found as amyloid aggregate deposits in the pancreatic islets of patients with type-2 diabetes and studies showed that insulin and its derivatives were the potent inhibitors of hIAPP aggregation. However, several emerging therapies with this goal showed limited success due to the instability and inefficiency of insulin derivatives. Nanosized graphene oxide (nGO) possesses high stability and affinity toward aromatic rings. In this study, an insulin-derived peptide, EALYLV, was stabilized by loading on nGO@PEG to inhibit aggregation and hIAPP-induced cytotoxicity. The results showed that nGO@PEG@EALYLV (abbreviated as nGO@PEG@E) can effectively inhibit the aggregation of hIAPP via electrostatic adsorption and specific binding to the active sites of hIAPP. We further evaluated the protective effect of nGO@PEG@E on INS-1 cells in the presence of hIAPP. Treatment with nGO@PEG@E could significantly elevate the viability of INS-1 cells, decrease the level of intracellular reactive oxygen species, and stabilize mitochondrial membrane potential. All the results indicated that nGO@PEG@E could inhibit the aggregation of hIAPP, which reduces its cytotoxicity.

Role of membrane biophysics in Alzheimer's-related cell pathways

Cellular membrane alterations are commonly observed in many diseases, including Alzheimer's disease (AD). Membrane biophysical properties, such as membrane molecular order, membrane fluidity, organization of lipid rafts, and adhesion between membrane and cytoskeleton, play an important role in various cellular activities and functions. While membrane biophysics impacts a broad range of cellular pathways, this review addresses the role of membrane biophysics in amyloid-β peptide aggregation, Aβ-induced oxidative pathways, amyloid precursor protein processing, and cerebral endothelial functions in AD. Understanding the mechanism(s) underlying the effects of cell membrane properties on cellular processes should shed light on the development of new preventive and therapeutic strategies for this devastating disease.

Enantiomers of cysteine-modified SeNPs (d/lSeNPs) as inhibitors of metal-induced Aβ aggregation in Alzheimer's disease

Chiral molecules, which selectively target and inhibit amyloid β-peptide (Aβ) aggregation, have potential use as therapeutic agents for the treatment of Alzheimer's disease (AD).