The application of nanotechnology in treatment of Alzheimer's disease

Polymeric nanoparticles: A promising strategy for treatment of Alzheimer's disease

Alzheimer's disease (AD), is characterised by two major hallmarks: the formation of extracellular β-amyloid (Aβ) plaques and the hyperphosphorylation of tau protein, thus leading to the formation of neurofibrillary tangles. These hallmarks cause synaptic loss, neuronal damage, and the development of neuroinflammation and oxidative stress, which promote AD progression. Thus, the goal of treating AD is eliminating these hallmarks, to prevent AD progression and decrease symptoms. However, current available therapies provide symptomatic relief rather than treating the underlying cause of the disease, because the restrictive nature of the blood brain barrier (BBB) impedes the entry of drugs, thereby affecting drug efficacy and bioavailability. Researchers are focusing on developing new therapeutic approaches to bypass the BBB, for achieving site-specific drug delivery with the highest possible bioavailability and the lowest adverse effects. Recently explored therapeutic strategies include use of biologic agents such as monoclonal antibodies. Aducanumab, a strong candidate for treating AD, has been granted accelerated Food and Drug Administration approval; however, safety concerns may hinder its future use. Thus, nanotechnological approaches have led to a new era of AD treatment. Nanoparticles (NPs), because of their small particle size, can cross the BBB, thus enhancing drug pharmacokinetic properties and enabling targeted drug delivery. Polymeric NPs have been extensively studied, because of their simple production, biodegradability, biocompatibility, and unique architecture. These NPs provide a flexible vesicle that can be easily tailored to achieve desired physicochemical features. In this review, various types of polymer-based-NPs are discussed, highlighting the properties of fabricated NPs, which have multiple benefits in AD treatment, including anti-amyloid, antioxidant, and anti-inflammatory effects.

Surface Reconstruction for Selective Oxidation of Tetrahydroisoquinoline

Integration of hydrogen evolution with the oxidation of organic substances in one electrochemical system is highly desirable. However, achieving selective oxidation of organic substances in the integrated system is still highly challenging. In this study, a phosphorylated NiMoO4 nanoneedle-like array was designed as the catalytic active electrode for the integration of highly selective electrochemical dehydrogenation of tetrahydroisoquinolines (THIQs) with hydrogen production. The leaching of anions, including MoO42- and PO43-, facilitates the reconstruction of the catalyst. As a result, nickel oxyhydroxides with the doping of PO43- and richness of defects are in situ formed. In situ Raman and density functional theory calculations have shown that the high catalytic activity is attributed to the in situ formed PO43- involved NiOOH substance. In the dehydrogenation process, the involved C-H bond but not the N-H bond is first destroyed. A two-electrode system was then fabricated with the optimized electrode that shows a benchmark current density of 10 mA cm-2 at 1.783 V, providing a yield of 70% for dihydroisoquinolines. A robust stability was also shown for this integrated electrochemical system. The understanding of the reconstruction behavior and the achievement of selective dehydrogenation will provide some hints for electrochemical synthesis.

Multifunctional nanoparticle-mediated combining therapy for human diseases

Combining existing drug therapy is essential in developing new therapeutic agents in disease prevention and treatment. In preclinical investigations, combined effect of certain known drugs has been well established in treating extensive human diseases. Attributed to synergistic effects by targeting various disease pathways and advantages, such as reduced administration dose, decreased toxicity, and alleviated drug resistance, combinatorial treatment is now being pursued by delivering therapeutic agents to combat major clinical illnesses, such as cancer, atherosclerosis, pulmonary hypertension, myocarditis, rheumatoid arthritis, inflammatory bowel disease, metabolic disorders and neurodegenerative diseases. Combinatorial therapy involves combining or co-delivering two or more drugs for treating a specific disease. Nanoparticle (NP)-mediated drug delivery systems, i.e., liposomal NPs, polymeric NPs and nanocrystals, are of great interest in combinatorial therapy for a wide range of disorders due to targeted drug delivery, extended drug release, and higher drug stability to avoid rapid clearance at infected areas. This review summarizes various targets of diseases, preclinical or clinically approved drug combinations and the development of multifunctional NPs for combining therapy and emphasizes combinatorial therapeutic strategies based on drug delivery for treating severe clinical diseases. Ultimately, we discuss the challenging of developing NP-codelivery and translation and provide potential approaches to address the limitations. This review offers a comprehensive overview for recent cutting-edge and challenging in developing NP-mediated combination therapy for human diseases.

The Major Hypotheses of Alzheimer's Disease: Related Nanotechnology-Based Approaches for Its Diagnosis and Treatment

Alzheimer's disease (AD) is a well-known chronic neurodegenerative disorder that leads to the progressive death of brain cells, resulting in memory loss and the loss of other critical body functions. In March 2019, one of the major pharmaceutical companies and its partners announced that currently, there is no drug to cure AD, and all clinical trials of the new ones have been cancelled, leaving many people without hope. However, despite the clear message and startling reality, the research continued. Finally, in the last two years, the Food and Drug Administration (FDA) approved the first-ever medications to treat Alzheimer's, aducanumab and lecanemab. Despite researchers' support of this decision, there are serious concerns about their effectiveness and safety. The validation of aducanumab by the Centers for Medicare and Medicaid Services is still pending, and lecanemab was authorized without considering data from the phase III trials. Furthermore, numerous reports suggest that patients have died when undergoing extended treatment. While there is evidence that aducanumab and lecanemab may provide some relief to those suffering from AD, their impact remains a topic of ongoing research and debate within the medical community. The fact is that even though there are considerable efforts regarding pharmacological treatment, no definitive cure for AD has been found yet. Nevertheless, it is strongly believed that modern nanotechnology holds promising solutions and effective clinical strategies for the development of diagnostic tools and treatments for AD. This review summarizes the major hallmarks of AD, its etiological mechanisms, and challenges. It explores existing diagnostic and therapeutic methods and the potential of nanotechnology-based approaches for recognizing and monitoring patients at risk of irreversible neuronal degeneration. Overall, it provides a broad overview for those interested in the evolving areas of clinical neuroscience, AD, and related nanotechnology. With further research and development, nanotechnology-based approaches may offer new solutions and hope for millions of people affected by this devastating disease.