Photooxidative inhibition and decomposition of β-amyloid in Alzheimer's by nano-assemblies of transferrin and indocyanine green

Nanomaterial-based approaches to neurotoxin neutralization in neurodegenerative diseases

Neurodegenerative diseases (NDs) are intricately linked to the accumulation of various neurotoxins, mainly including toxic proteins, inflammatory mediators, excess metal ions, and viral pathogens. Biological neutralization strategies that use agents to competitively bind harmful substances and thus inhibit their pathogenic activity hold promise for direct removal of neurotoxins but face many limitations and challenges in NDs. Nanomaterials provide a potential solution for neurotoxin neutralization in NDs due to their unique physicochemical and biological properties. This review summarizes recent advancements in nanomaterial-based approaches to neurotoxin neutralization in NDs, highlighting the diverse design principles and mechanisms of action. We also discuss the critical role of targeted delivery to optimize neutralization efficiency and the advantages of combining different neutralization mechanisms or introducing other therapeutic components to exert the synergistic effects. Furthermore, we reveal current limitations and future research directions aimed at paving the way for nanomedicine development based on neurotoxin neutralization for the treatment of NDs.

Multifunctional selenium-doped carbon dots for modulating Alzheimer's disease related toxic ions, inhibiting amyloid aggregation and scavenging reactive oxygen species

β-Amyloid (Aβ) protein deposition, oxidative stress, and metal ion imbalance are established pathological features of Alzheimer's disease (AD), highlighting the imperative to efficiently reduce Aβ aggregates formation, alleviate oxidative stress, and chelate metal ions. Existing research indicates the necessity of developing multifunctional nanomaterials to facilitate multi-target therapy. In this work, we designed and prepared multifunctional selenium-doped carbonized polymer dots (SeCDs), and examined the multifunctionality at inhibiting Aβ, cleaning reactive oxygen species (ROS), and modulating copper ions. SeCDs exhibit efficient clearance of active hydroxyl radicals and superoxide anion radicals. In addition, SeCDs can chelate Cu ions, therefore reducing the cytotoxicity linked to the Aβ-Cu complex. More importantly, SeCDs can effectively reduce the level of intracellular reactive oxygen species. This study demonstrates the potential of carbon dots as a multifunctional β-sheet disruptor, while multifunctional SeCDs offer promising avenues for further research in the multi-target treatment of Alzheimer's disease. Meanwhile, this strategy provides a new perspective on the development of zero-dimensional carbon materials in Alzheimer's therapy.

Photocatalytic, photothermal, and blood-brain barrier-permeable carbon nanodots: A potent multifunctional scavenger for β-amyloid plaque

Alzheimer's disease (AD) is associated with amyloid production and buildup in the brain, leading to neurodegeneration. In this study, we used a solvent-thermal technique to produce light-sensitive carbon nanodots (L-CNDs). L-CNDs exhibit outstanding photocatalytic properties, producing singlet oxygen (1O2) under 630 nm irradiation. L-CNDs have a high photothermal conversion efficiency of 68.25 % under 808 nm irradiation, allowing for localized heating and regulation of Aβ aggregation. L-CNDs bind Aβ through hydrophobic interaction and π-π stacking. L-CNDs inhibit Aβ aggregation with efficiencies of 61.08 %, 75.09 %, and 91.72 % at 10 μg·mL-1 in photothermal therapy (PTT), photodynamic therapy (PDT), and PTT/PDT synergistic therapy, respectively. L-CNDs efficiently suppress Aβ misfolding, inhibit fibrillation, and promote disaggregation of mature fibrils. L-CNDs mitigate Aβ-induced cytotoxicity in PC12 and HT22 cells. Interestingly, the data showed that 84.6 % of the L-CNDs could penetrate bEnd.3 cells after 8 h of treatment, demonstrating that they have the capacity to cross the blood-brain barrier (BBB) because of their small size. In vitro investigations have shown that L-CNDs can pass through the BBB. Collectively, our findings reveal a unique technique for treating amyloid disorders using carbon nanodots with significant potential for future studies in this area.

Blood-brain barrier permeable carbon nano-assemblies for amyloid-β clearance and neurotoxic attenuation

Abnormal amyloid β-protein (Aβ42) fibrillation is a key event in Alzheimer's disease (AD), and photodynamic therapy (PDT) possesses great potential in modulating Aβ42 self-assembly. However, the poor blood-brain barrier (BBB) penetration, low biocompatibility, and limited tissue penetration depth of existing photosensitizers limit the progress of photo-oxidation strategies. In this paper, novel indocyanine green-modified graphene quantum dot nano-assemblies (NBGQDs-ICGs) were synthesized based on a molecular assembly strategy of electrostatic interactions for PDT inhibition of Aβ42 self-assembly process and decomposition of preformed fibrils under near-infrared light. Combining the small-size structure of graphene quantum dots and the near-infrared light-responsive properties of ICGs, the NBGQDs-ICGs could achieve BBB penetration under 808 nm irradiation. More importantly, the neuroprotective mechanism of NBGQDs-ICG was studied for the first time by AFM, which effectively weakened the adhesion of Aβ42 aggregates to the cell surface by blocking the interaction between Aβ42 and the cell membrane, and restored the mechanical stability and adhesion of the neuron membrane. Meanwhile, NBGQDs-ICG promoted phagocytosis of Aβ42 by microglia. In addition, the good biocompatibility and stability ensured the biosafety of NBGQDs-ICG in future clinical applications. We anticipate that such multifunctional nanocomponents may provide promising avenues for the development of novel AD inhibitors.

Indocyanine green-mediated fabrication of urchin-like hydroxyethyl starch nanocarriers for enhanced drug tumor EPR and deep penetration effects

Effective EPR and tumor penetration are bottlenecks in current nanomedicine therapy. Comosol software was utilized to analyze the motion process of nanoparticles (NPs) with different shapes, from blood vessels to tumor tissue, to address this. By calculation, urchin-like NPs experienced higher drag forces than spherical NPs, facilitating their EPR and tumor penetration effects. Thus, urchin-like indocyanine green-loaded hydroxyethyl starch-cholesterol (ICG@HES-CH) NPs were prepared by leveraging the instability of ICG responding to near-infrared light (NIR). Upon NIR exposure, ICG degraded and partly disintegrated ICG@HES-CH NPs, and its morphology transformed from spherical to urchin-like. Vincristine (VC), as a model drug, was loaded in urchin-like ICG@HES-CH NPs for the treatment of lymphoma. A20 lymphoma cells and 3T3-A20 tumor organoids were employed to investigate the influence of shape on NPs' cellular uptake, penetration pathway, and cytotoxicity. It demonstrated that urchin-like ICG@HES-CH NPs mainly transport across the extracellular matrix through intercellular pathways, easily reaching the deep tumor sites and achieving higher cytotoxicity. In vivo VC distribution and anti-tumor results indicated that urchin-like NPs increased VC EPR and penetration ability, lowering VC neurotoxicity and superior anti-tumor effect. Therefore, urchin-like ICG@HES-CH NPs have great translational potential to be used as chemotherapeutic nanocarriers in anticancer therapy.

Advances and future perspectives of intranasal drug delivery: A scientometric review

Intranasal drug delivery is as a noninvasive and efficient approach extensively utilized for treating the local, central nervous system, and systemic diseases. Despite numerous reviews delving into the application of intranasal drug delivery across biomedical fields, a comprehensive analysis of advancements and future perspectives remains elusive. This review elucidates the research progress of intranasal drug delivery through a scientometric analysis. It scrutinizes several challenges to bolster research in this domain, encompassing a thorough exploration of entry and elimination mechanisms specific to intranasal delivery, the identification of drugs compatible with the nasal cavity, the selection of dosage forms to surmount limited drug-loading capacity and poor solubility, and the identification of diseases amenable to the intranasal delivery strategy. Overall, this review furnishes a perspective aimed at galvanizing future research and development concerning intranasal drug delivery.

Phenyl-quinoline derivatives as lead structure of cholinesterase inhibitors with potency to reduce the GSK-3β level targeting Alzheimer's disease

Alzheimer's disease (AD) is a neurodegenerative disorder that leads to cognitive decline and memory loss. Unfortunately, there is no effective treatment for this condition, so there is a growing interest in developing new anti-AD agents. In this research project, a series of phenyl-quinoline derivatives were designed as potential anti-AD agents. These derivatives were substituted at two different positions on benzyl and phenyl rings. The structures of the derivatives were characterized using techniques such as IR spectroscopy, 1H NMR, 13C NMR, and elemental analysis. During the in vitro screening, the derivatives were tested against both acetylcholinesterase (AChE) and butyrylcholinesterase (BChE). It was observed that most of the derivatives showed higher selectivity against BChE compared to AChE. Among the derivatives, analog 7n (with a methoxy group at R1 and a 4-bromine substituent at R2 exhibited the highest potency, with a 75-fold improvement in the activity compared to the positive control. Importantly, this potent analog demonstrated no toxicity at the tested concentration on SH-SY5Y cells, indicating its potential as a safe anti-AD agent. The level of GSK-3β was also reduced after treatments with 7n at 50 μM. Overall, this study highlights the design and evaluation of phenyl-quinoline derivatives as promising candidates for developing novel anti-AD agents.