"Swiss Army Knife" black phosphorus-based nanodelivery platform for synergistic antiparkinsonian therapy via remodeling the brain microenvironment

Highly BBB-permeable nanomedicine reverses neuroapoptosis and neuroinflammation to treat Alzheimer's disease

The prevalence of Alzheimer's disease (AD) is increasing globally due to population aging. However, effective clinical treatment strategies for AD still remain elusive. The mechanisms underlying AD onset and the interplay between its pathological factors have so far been unclear. Evidence indicates that AD progression is ultimately driven by neuronal loss, which in turn is caused by neuroapoptosis and neuroinflammation. Therefore, the inhibition of neuroapoptosis and neuroinflammation could be a useful anti-AD strategy. Nonetheless, the delivery of active drug agents into the brain parenchyma is hindered by the blood-brain barrier (BBB). To address this challenge, we fabricated a black phosphorus nanosheet (BP)-based methylene blue (MB) delivery system (BP-MB) for AD therapy. After confirming the successful preparation of BP-MB, we proved that its BBB-crossing ability was enhanced under near-infrared light irradiation. In vitro pharmacodynamics analysis revealed that BP and MB could synergistically scavenge excessive reactive oxygen species (ROS) in okadaic acid (OA)-treated PC12 cells and lipopolysaccharide (LPS)-treated BV2 cells, thus efficiently reversing neuroapoptosis and neuroinflammation. To study in vivo pharmacodynamics, we established a mouse model of AD mice, and behavioral tests confirmed that BP-MB treatment could successfully improve cognitive function in these animals. Notably, the results of pathological evaluation were consistent with those of the in vitro assays. The findings demonstrated that BP-MB could scavenge excessive ROS and inhibit Tau hyperphosphorylation, thereby alleviating downstream neuroapoptosis and regulating the polarization of microglia from the pro-inflammatory M1 phenotype to the anti-inflammatory M2 phenotype. Overall, this study highlights the therapeutic potential of a smart nanomedicine with the capability of reversing neuroapoptosis and neuroinflammation for AD treatment.

Surface Engineering of Two-Dimensional Black Phosphorus for Advanced Nanophotonics

ConspectusEverything in the world has two sides. We should correctly understand its two sides to pursue the positive side and get rid of the negative side. Recently, two-dimensional (2D) black phosphorus (BP) has received a tremendous amount of attention and has been applied for broad applications in optoelectronics, transistors, logic devices, and biomedicines due to its intrinsic properties, e.g., thickness-dependent bandgap, high mobility, highly anisotropic charge transport, and excellent biodegradability and biocompatibility. On one hand, rapid degradation of 2D BP under ambient conditions becomes a vital bottleneck that largely hampers its practical applications in optical and optoelectronic devices and photocatalysis. On the other hand, just because of its ambient instability, 2D BP as a novel kind of nanomedicine in a cancer drug delivery system can not only satisfy effective cancer therapy but also enable its safe biodegradation in vivo. Until now, a variety of surface functionality types and approaches have been employed to rationally modify 2D BP to meet the growing requirements of advanced nanophotonics.In this Account, we describe our research on surface engineering of 2D BP in two opposite ways: (i) stabilizing 2D BP by various approaches for advanced nanophotonic devices with both remarkable photoresponse behavior and environmentally structural stability and (ii) making full use of biodegradation, biocompatibility, and biological activity (e.g., photothermal therapy, photodynamic therapy, and bioimaging) of 2D BP for the construction of high-performance delivery nanoplatforms for biophotonic applications. We highlight the targeted aims of the surface-engineered 2D BP for advanced nanophotonics, including photonic devices (optics, optoelectronics, and photocatalysis) and photoinduced cancer therapy, by means of various surface functionalities, such as heteroatom incorporation, polymer functionalization, coating, heterostructure design, etc. From the viewpoint of potential applications, the fundamental properties of surface-engineered 2D BP and recent advances in surface-engineered 2D BP-based nanophotonic devices are briefly discussed. For the photonic devices, surface-engineered 2D BP can not only effectively improve environmentally structural stability but also simultaneously maintain photoresponse performance, enabling 2D BP-based devices for a wide range of practical applications. In terms of the photoinduced cancer therapy, surface-engineered 2D BP is more appropriate for the treatment of cancer due to negligible toxicity and excellent biodegradation and biocompatibility. We also provide our perspectives on future opportunities and challenges in this important and fast-growing field. It is envisioned that this Account can attract more attention in this area and inspire more scientists in a variety of research communities to accelerate the development of 2D BP for more widespread high-performance nanophotonic applications.

Brain-Targeted Black Phosphorus-Based Nanotherapeutic Platform for Enhanced Hypericin Delivery in Depression

Depression is a significant global health concern that remains inadequately treated due to the limited effectiveness of conventional drug therapies. One potential therapeutic agent, hypericin (HYP), is identified as an effective natural antidepressant. However, its poor water solubility, low bioavailability, and limited ability to penetrate the brain parenchyma have hindered its clinical application. To address these shortcomings and enhance the therapeutic efficacy of HYP, it is loaded onto black phosphorus nanosheets (BP) modified with the neural cell-targeting peptide RVG29 to synthesize a nanoplatform named BP-RVG29@HYP (BRH). This platform served as a nanocarrier for HYP and integrated the advantages of BP with advanced delivery methods and precise targeting strategies. Under the influence of 808 nm near-infrared irradiation (NIR), BRH effectively traversed an in vitro BBB model. In vivo experiments validated these findings, demonstrating that treatment with BRH significantly alleviated depressive-like behaviors and oxidative stress in mice. Importantly, BRH exhibited an excellent safety profile, causing minimal adverse effects, which highlighted its potential as a promising therapeutic agent. In brief, this novel nanocarrier holds great promise in the development of antidepressant drugs and can create new avenues for the treatment of depression.

Ameliorating Mitochondrial Dysfunction for the Therapy of Parkinson's Disease

Parkinson's disease (PD) is currently the second most incurable central neurodegenerative disease resulting from various pathogenesis. As the "energy factory" of cells, mitochondria play an extremely important role in supporting neuronal signal transmission and other physiological activities. Mitochondrial dysfunction can cause and accelerate the occurrence and progression of PD. How to effectively prevent and suppress mitochondrial disorders is a key strategy for the treatment of PD from the root. Therefore, the emerging mitochondria-targeted therapy has attracted considerable interest. Herein, the relationship between mitochondrial dysfunction and PD, the causes and results of mitochondrial dysfunction, and major strategies for ameliorating mitochondrial dysfunction to treat PD are systematically reviewed. The study also prospects the main challenges for the treatment of PD.

Nanodrug Delivery Systems for Myasthenia Gravis: Advances and Perspectives

Myasthenia gravis (MG) is a rare chronic autoimmune disease caused by the production of autoantibodies against the postsynaptic membrane receptors present at the neuromuscular junction. This condition is characterized by fatigue and muscle weakness, including diplopia, ptosis, and systemic impairment. Emerging evidence suggests that in addition to immune dysregulation, the pathogenesis of MG may involve mitochondrial damage and ferroptosis. Mitochondria are the primary site of energy production, and the reactive oxygen species (ROS) generated due to mitochondrial dysfunction can induce ferroptosis. Nanomedicines have been extensively employed to treat various disorders due to their modifiability and good biocompatibility, but their application in MG management has been rather limited. Nevertheless, nanodrug delivery systems that carry immunomodulatory agents, anti-oxidants, or ferroptosis inhibitors could be effective for the treatment of MG. Therefore, this review focuses on various nanoplatforms aimed at attenuating immune dysregulation, restoring mitochondrial function, and inhibiting ferroptosis that could potentially serve as promising agents for targeted MG therapy.

Customized Intranasal Hydrogel Delivering Methylene Blue Ameliorates Cognitive Dysfunction against Alzheimer's Disease

The accumulation of hyperphosphorylated tau protein aggregates is a key pathogenic event in Alzheimer's disease (AD) and induces mitochondrial dysfunction and reactive oxygen species overproduction. However, the treatment of AD remains challenging owning to the hindrance caused by the blood-brain barrier (BBB) and the complex pathology of AD. Nasal delivery represents an effective means of circumventing the BBB and delivering drugs to the brain. In this study, black phosphorus (BP) is used as a drug carrier, as well as an antioxidant, and loaded with a tau aggregation inhibitor, methylene blue (MB), to obtain BP-MB. For intranasal (IN) delivery, a thermosensitive hydrogel is fabricated by cross-linking carboxymethyl chitosan and aldehyde Pluronic F127 (F127-CHO) micelles. The BP-MB nanocomposite is incorporated into the hydrogel to obtain BP-MB@Gel. BP-MB@Gel could be injected intranasally, providing high nasal mucosal retention and controlled drug release. After IN administration, BP-MB is continuously released and delivered to the brain, exerting synergistic therapeutic effects by suppressing tau neuropathology, restoring mitochondrial function, and alleviating neuroinflammation, thus inducing cognitive improvements in mouse models of AD. These findings highlight a potential strategy for brain-targeted drug delivery in the management of the complex pathologies of AD.

Focused ultrasound-mediated cerium-based nanoreactor against Parkinson's disease via ROS regulation and microglia polarization

Neuronal damage caused by oxidative stress and inflammatory microenvironment dominated by microglia are the main obstacles in the treatment of Parkinson's disease (PD). In this study, we developed an integrated nanoreactor Q@CeBG by encapsulating CeO2 nanozyme and quercetin (Que) into glutathione-modified bovine serum albumin, and then selected focused ultrasound (FUS) to temporarily open the blood-brain barrier (BBB) to enhance the accumulation level of Q@CeBG in the brain. Q@CeBG exhibited superior multi-ROS scavenging activity. Under the assistance of FUS, Q@CeBG nanoreactor can penetrate the BBB and act on neurons as well as microglia, reducing the neuron's oxidative stress level and polarizing microglia's phenotype from proinflammatory M1 to anti-inflammatory M2. In vitro and In vivo experiments demonstrated that Q@CeBG nanoreactor with good biocompatibility exhibit outstanding neuroprotection and immunomodulatory effects. In short, this dual synergetic nanoreactor will become a reliable platform against PD.

Microwave-responsive gadolinium metal-organic frameworks nanosystem for MRI-guided cancer thermotherapy and synergistic immunotherapy

The clinical application of cancer immunotherapy is unsatisfied due to low response rates and systemic immune-related adverse events. Microwave hyperthermia can be used as a synergistic immunotherapy to amplify the antitumor effect. Herein, we designed a Gd-based metal-organic framework (Gd-MOF) nanosystem for MRI-guided thermotherapy and synergistic immunotherapy, which featured high performance in drug loading and tumor tissue penetration. The PD-1 inhibitor (aPD-1) was initially loaded in the porous Gd-MOF (Gd/M) nanosystem. Then, the phase change material (PCM) and the cancer cell membrane were further sequentially modified on the surface of Gd/MP to obtain Gd-MOF@aPD-1@CM (Gd/MPC). When entering the tumor microenvironment (TME), Gd/MPC induces immunogenic death of tumor cells through microwave thermal responsiveness, improves tumor suppressive immune microenvironment and further enhances anti-tumor ability of T cells by releasing aPD-1. Meanwhile, Gd/MPC can be used for contrast-enhanced MRI. Transcriptomics data revealed that the downregulation of MSK2 in cancer cells leads to the downregulation of c-fos and c-jun, and ultimately leads to the apoptosis of cancer cells after treatment. In general, Gd/MPC nanosystem not only solves the problem of system side effect, but also achieves the controlled drug release via PCM, providing a promising theranostic nanoplatform for development of cancer combination immunotherapy.

Micro/nanosystems for controllable drug delivery to the brain

Drug delivery to the brain is crucial in the treatment for central nervous system disorders. While significant progress has been made in recent years, there are still major challenges in achieving controllable drug delivery to the brain. Unmet clinical needs arise from various factors, including controlled drug transport, handling large drug doses, methods for crossing biological barriers, the use of imaging guidance, and effective models for analyzing drug delivery. Recent advances in micro/nanosystems have shown promise in addressing some of these challenges. These include the utilization of microfluidic platforms to test and validate the drug delivery process in a controlled and biomimetic setting, the development of novel micro/nanocarriers for large drug loads across the blood-brain barrier, and the implementation of micro-intervention systems for delivering drugs through intraparenchymal or peripheral routes. In this article, we present a review of the latest developments in micro/nanosystems for controllable drug delivery to the brain. We also delve into the relevant diseases, biological barriers, and conventional methods. In addition, we discuss future prospects and the development of emerging robotic micro/nanosystems equipped with directed transportation, real-time image guidance, and closed-loop control.

The blood-brain barrier: structure, regulation, and drug delivery

Blood-brain barrier (BBB) is a natural protective membrane that prevents central nervous system (CNS) from toxins and pathogens in blood. However, the presence of BBB complicates the pharmacotherapy for CNS disorders as the most chemical drugs and biopharmaceuticals have been impeded to enter the brain. Insufficient drug delivery into the brain leads to low therapeutic efficacy as well as aggravated side effects due to the accumulation in other organs and tissues. Recent breakthrough in materials science and nanotechnology provides a library of advanced materials with customized structure and property serving as a powerful toolkit for targeted drug delivery. In-depth research in the field of anatomical and pathological study on brain and BBB further facilitates the development of brain-targeted strategies for enhanced BBB crossing. In this review, the physiological structure and different cells contributing to this barrier are summarized. Various emerging strategies for permeability regulation and BBB crossing including passive transcytosis, intranasal administration, ligands conjugation, membrane coating, stimuli-triggered BBB disruption, and other strategies to overcome BBB obstacle are highlighted. Versatile drug delivery systems ranging from organic, inorganic, and biologics-derived materials with their synthesis procedures and unique physio-chemical properties are summarized and analyzed. This review aims to provide an up-to-date and comprehensive guideline for researchers in diverse fields, offering perspectives on further development of brain-targeted drug delivery system.