Click chemistry extracellular vesicle/peptide/chemokine nanomissiles for treating central nervous systems injuries

Nature's carriers: leveraging extracellular vesicles for targeted drug delivery

With the rapid development of drug delivery systems, extracellular vesicles (EVs) have emerged as promising stars for improving targeting abilities and realizing effective delivery. Numerous studies have shown when compared to conventional strategies in targeted drug delivery (TDD), EVs-based strategies have several distinguished advantages besides targeting, such as participating in cell-to-cell communications and immune response, showing high biocompatibility and stability, penetrating through biological barriers, etc. In this review, we mainly focus on the mass production of EVs including the challenges and strategies for scaling up EVs production in a cost-effective and reproducible manner, the loading and active targeting methods, and examples of EVs as vehicles for TDD in consideration of potential safety and regulatory issues associated. We also conclude and discuss the rigor and reproducibility of EVs production, the current research status of the application of EVs-based strategies to targeted drug delivery, clinical conversion prospects, and existing chances and challenges.

Functional biomaterials for modulating the dysfunctional pathological microenvironment of spinal cord injury

Spinal cord injury (SCI) often results in irreversible loss of sensory and motor functions, and most SCIs are incurable with current medical practice. One of the hardest challenges in treating SCI is the development of a dysfunctional pathological microenvironment, which mainly comprises excessive inflammation, deposition of inhibitory molecules, neurotrophic factor deprivation, glial scar formation, and imbalance of vascular function. To overcome this challenge, implantation of functional biomaterials at the injury site has been regarded as a potential treatment for modulating the dysfunctional microenvironment to support axon regeneration, remyelination at injury site, and functional recovery after SCI. This review summarizes characteristics of dysfunctional pathological microenvironment and recent advances in biomaterials as well as the technologies used to modulate inflammatory microenvironment, regulate inhibitory microenvironment, and reshape revascularization microenvironment. Moreover, technological limitations, challenges, and future prospects of functional biomaterials to promote efficient repair of SCI are also discussed. This review will aid further understanding and development of functional biomaterials to regulate pathological SCI microenvironment.

Drop to Gate Nasal Drops Attenuates Sepsis-Induced Cognitive Dysfunction

Nasal administration can bypass the blood-brain barrier and directly deliver drugs to the brain, providing a non-invasive route for central nervous system (CNS) diseases. Inspired by the appearance that a gate can block the outside world and the characteristics of the sol-gel transition can form a "gate" in the nasal cavity, a Drop to Gate nasal drop (DGND) is designed to set a gate in nose, which achieves protecting role from the influence of nasal environment. The DGND demonstrates the efficiency and application prospect of delivering drugs to the brain through the N-to-B. The effective concentration of single administration is increased through the hydrophobic interaction between C8-GelMA and SRT1720 (SA), and then cross-linked under UV to form nanogel, which can respond to MMP in the inflammatory microenvironment of sepsis-induced cognitive dysfunction. Finally, the SA/nanogel is compounded into the thermogel, which can respond to the nasal cavity temperature to form DGND in situ, increasing the residence time and delivery efficiency of drugs in the nasal cavity. In vitro, the DGND alleviates lipopolysaccharides (LPS)-induced BV2 inflammation. In vivo, DGND effectively targets the nasal mucosa and deliver drugs to the brain, which activate Sirt1 to alleviate inflammation mediated by microglia and improve cognitive dysfunction in sepsis mice.

An Overview on the Physiopathology of the Blood-Brain Barrier and the Lipid-Based Nanocarriers for Central Nervous System Delivery

The state of well-being and health of our body is regulated by the fine osmotic and biochemical balance established between the cells of the different tissues, organs, and systems. Specific districts of the human body are defined, kept in the correct state of functioning, and, therefore, protected from exogenous or endogenous insults of both mechanical, physical, and biological nature by the presence of different barrier systems. In addition to the placental barrier, which even acts as a linker between two different organisms, the mother and the fetus, all human body barriers, including the blood-brain barrier (BBB), blood-retinal barrier, blood-nerve barrier, blood-lymph barrier, and blood-cerebrospinal fluid barrier, operate to maintain the physiological homeostasis within tissues and organs. From a pharmaceutical point of view, the most challenging is undoubtedly the BBB, since its presence notably complicates the treatment of brain disorders. BBB action can impair the delivery of chemical drugs and biopharmaceuticals into the brain, reducing their therapeutic efficacy and/or increasing their unwanted bioaccumulation in the surrounding healthy tissues. Recent nanotechnological innovation provides advanced biomaterials and ad hoc customized engineering and functionalization methods able to assist in brain-targeted drug delivery. In this context, lipid nanocarriers, including both synthetic (liposomes, solid lipid nanoparticles, nanoemulsions, nanostructured lipid carriers, niosomes, proniosomes, and cubosomes) and cell-derived ones (extracellular vesicles and cell membrane-derived nanocarriers), are considered one of the most successful brain delivery systems due to their reasonable biocompatibility and ability to cross the BBB. This review aims to provide a complete and up-to-date point of view on the efficacy of the most varied lipid carriers, whether FDA-approved, involved in clinical trials, or used in in vitro or in vivo studies, for the treatment of inflammatory, cancerous, or infectious brain diseases.

Astrocyte-Derived Extracellular Vesicles for Ischemic Stroke: Therapeutic Potential and Prospective

Stroke is a leading cause of death and disability in the world. Astrocytes are special glial cells within the central nervous system and play important roles in mediating neuroprotection and repair processes during stroke. Extracellular vesicles (EVs) are lipid bilayer particles released from cells that facilitate intercellular communication in stroke by delivering proteins, lipids, and RNA to target cells. Recently, accumulating evidence suggested that astrocyte-derived EVs (ADEVs) are actively involved in mediating numerous biological processes including neuroprotection and neurorepair in stroke and they are realized as an excellent therapeutic approach for treating stroke. In this review we systematically summarize the up-to-date research on ADEVs in stroke, and prospects for its potential as a novel therapeutic target for stroke. We also provide an overview of the effects and functions of ADEVs on stroke recovery, which may lead to developing clinically relevant therapies for stroke.

Recent advances in therapeutic engineered extracellular vesicles

Extracellular vesicles (EVs) are natural particles secreted by living cells, which hold significant potential for various therapeutic applications. Native EVs have specific components and structures, allowing them to cross biological barriers, and circulate in vivo for a long time. Native EVs have also been bioengineered to enhance their therapeutic efficacy and targeting affinity. Recently, the therapeutic potential of surface-engineered EVs has been explored in the treatment of tumors, autoimmune diseases, infections and other diseases by ongoing research and clinical trials. In this review, we will introduce the modified methods of engineered EVs, summarize the application of engineered EVs in preclinical and clinical trials, and discuss the opportunities and challenges for the clinical translation of surface-engineered EVs.

Bioorthogonal microglia-inspired mesenchymal stem cell bioengineering system creates livable niches for enhancing ischemic stroke recovery via the hormesis

Mesenchymal stem cells (MSCs) experience substantial viability issues in the stroke infarct region, limiting their therapeutic efficacy and clinical translation. High levels of deadly reactive oxygen radicals (ROS) and proinflammatory cytokines (PC) in the infarct milieu kill transplanted MSCs, whereas low levels of beneficial ROS and PC stimulate and improve engrafted MSCs' viability. Based on the intrinsic hormesis effects in cellular biology, we built a microglia-inspired MSC bioengineering system to transform detrimental high-level ROS and PC into vitality enhancers for strengthening MSC therapy. This system is achieved by bioorthogonally arming metabolic glycoengineered MSCs with microglial membrane-coated nanoparticles and an antioxidative extracellular protective layer. In this system, extracellular ROS-scavenging and PC-absorbing layers effectively buffer the deleterious effects and establish a micro-livable niche at the level of a single MSC for transplantation. Meanwhile, the infarct's inanimate milieu is transformed at the tissue level into a new living niche to facilitate healing. The engineered MSCs achieved viability five times higher than natural MSCs at seven days after transplantation and exhibited a superior therapeutic effect for stroke recovery up to 28 days. This vitality-augmented system demonstrates the potential to accelerate the clinical translation of MSC treatment and boost stroke recovery.

Clicking in harmony: exploring the bio-orthogonal overlap in click chemistry

In the quest to scrutinize and modify biological systems, the global research community has continued to explore bio-orthogonal click reactions, a set of reactions exclusively targeting non-native molecules within biological systems. These methodologies have brought about a paradigm shift, demonstrating the feasibility of artificial chemical reactions occurring on cellular surfaces, in the cell cytosol, or within the body - an accomplishment challenging to achieve with the majority of conventional chemical reactions. This review delves into the principles of bio-orthogonal click chemistry, contrasting metal-catalyzed and metal-free reactions of bio-orthogonal nature. It comprehensively explores mechanistic details and applications, highlighting the versatility and potential of this methodology in diverse scientific contexts, from cell labelling to biosensing and polymer synthesis. Researchers globally continue to advance this powerful tool for precise and selective manipulation of biomolecules in complex biological systems.

Standardized Method to Functionalize Plasma-Extracellular Vesicles via Copper-Free Click Chemistry for Targeted Drug Delivery Strategies

Extracellular vesicles (EVs) have emerged as potential vehicles for targeted drug delivery and diagnostic applications. However, achieving consistent and reliable functionalization of EV membranes remains a challenge. Copper-catalyzed click chemistry, commonly used for EV surface modification, poses limitations due to cytotoxicity and interference with biological systems. To overcome these limitations, we developed a standardized method for functionalizing an EV membrane via copper-free click chemistry. EVs derived from plasma hold immense potential as diagnostic and therapeutic agents. However, the isolation and functionalization of EVs from such a complex biofluid represent considerable challenges. We compared three different EV isolation methods to obtain an EV suspension with an optimal purity/yield ratio, and we identified sucrose cushion ultracentrifugation (sUC) as the ideal protocol. We then optimized the reaction conditions to successfully functionalize the plasma-EV surface through a copper-free click chemistry strategy with a fluorescently labeled azide, used as a proof-of-principle molecule. Click-EVs maintained their identity, size, and, more importantly, capacity to be efficiently taken up by responder tumor cells. Moreover, once internalized, click EVs partially followed the endosomal recycling route. The optimized reaction conditions and characterization techniques presented in this study offer a foundation for future investigations and applications of functionalized EVs in drug delivery, diagnostics, and therapeutics.

Physio-chemical Modifications to Re-engineer Small Extracellular Vesicles for Targeted Anticancer Therapeutics Delivery and Imaging

Cancer theranostics developed through nanoengineering applications are essential for targeted oncologic interventions in the new era of personalized and precision medicine. Recently, small extracellular vesicles (sEVs) have emerged as an attractive nanoengineering platform for tumor-directed anticancer therapeutic delivery and imaging of malignant tumors. These natural nanoparticles have multiple advantages over synthetic nanoparticle-based delivery systems, such as intrinsic targeting ability, less immunogenicity, and a prolonged circulation time. Since the inception of sEVs as a viable replacement for liposomes (synthetic nanoparticles) as a drug delivery vehicle, many studies have attempted to further the therapeutic efficacy of sEVs. This article discusses engineering strategies for sEVs using physical and chemical methods to enhance their anticancer therapeutic delivery performance. We review physio-chemical techniques of effective therapeutic loading into sEV, sEV surface engineering for targeted entry of therapeutics, and its cancer environment sensitive release inside the cells/organ. Next, we also discuss the novel hybrid sEV systems developed by a combination of sEVs with lipid and metal nanoparticles to garner each component's benefits while overcoming their drawbacks. The article extensively analyzes multiple sEV labeling techniques developed and investigated for live tracking or imaging sEVs. Finally, we discuss the theranostic potential of engineered sEVs in future cancer care regimens.

Ultrasound-nanovesicles interplay for theranostics

Nanovesicles (NVs) are widely used in the treatment and diagnosis of diseases due to their excellent vascular permeability, good biocompatibility, high loading capacity, and easy functionalization. However, their yield and in vivo penetration depth limitations and their complex preparation processes still constrain their application and development. Ultrasound, as a fundamental external stimulus with deep tissue penetration, concentrated energy sources, and good safety, has been proven to be a patient-friendly and highly efficient strategy to overcome the restrictions of traditional clinical medicine. Recent research has shown that ultrasound can drive the generation of NVs, increase their yield, simplify their preparation process, and provide direct therapeutic effects and intelligent control to enhance the therapeutic effect of NVs. In addition, NVs, as excellent drug carriers, can enhance the targeting efficiency of ultrasound-based sonodynamic therapy or sonogenetic regulation and improve the accuracy of ultrasound imaging. This review provides a detailed introduction to the classification, generation, and modification strategies of NVs, emphasizing the impact of ultrasound on the formation of NVs and summarizing the enhanced treatment and diagnostic effects of NVs combined with ultrasound for various diseases.

Nanoinjection of extracellular vesicles to single live cells by robotic fluidic force microscopy

In the past decade, extracellular vesicles (EVs) have attracted substantial interest in biomedicine. With progress in the field, we have an increasing understanding of cellular responses to EVs. In this Technical Report, we describe the direct nanoinjection of EVs into the cytoplasm of single cells of different cell lines. By using robotic fluidic force microscopy (robotic FluidFM), nanoinjection of GFP positive EVs and EV-like particles into single live HeLa, H9c2, MDA-MB-231 and LCLC-103H cells proved to be feasible. This injection platform offered the advantage of high cell selectivity and efficiency. The nanoinjected EVs were initially localized in concentrated spot-like regions within the cytoplasm. Later, they were transported towards the periphery of the cells. Based on our proof-of-principle data, robotic FluidFM is suitable for targeting single living cells by EVs and may lead to information about intracellular EV cargo delivery at a single-cell level.

Emerging technologies for engineering of extracellular vesicles

Extracellular vesicles (EVs) are lipid-bilayer membrane-enclosed vesicles that are secreted by all cell types. Natural EVs contain biological information such as proteins, nucleic acids, and lipids from their parent cells. Therefore, EVs have been extensively studied as diagnostic biomarkers and therapeutic tools under normal and pathological conditions. However, some drawbacks, including low yield, poor therapeutic effects, lack of imaging, and targeting capacity of natural EVs, still need to be improved. Emerging engineering technologies have rendered EVs new properties or functionalities that broadened their applications in the biomedical field. Herein, in this review, we gave a brief overview of advanced strategies for EV engineering. We focused on pre-treatment of parent cells to regulate their released EVs. Meanwhile, we summarized and discussed the direct modification of EVs to achieve drug loading, imaging, and targeting functionalities for downstream applications.

Bio-clickable, small extracellular vesicles-COCKTAIL therapy for ischemic stroke

Delivering large therapeutic molecules via the blood-brain barrier to treat ischemic stroke remains challenging. NR2B9c is a potent neuroprotective peptide but it's safe and targeted delivery to the brain requires an efficient, natural, and non-immunogenic delivery technique. Small extracellular vesicles (sEVs) have shown great potential as a non-immunogenic, natural cargo delivery system; however, tailoring of its inefficient brain targeting is desired. Here, we coupled rabies virus glycoprotein 29 with sEVs surface via bio-orthogonal click chemistry reactions, followed by loading of NR2B9c, ultimately generating stroke-specific therapeutic COCKTAIL (sEVs-COCKTAIL). Primary neurons and Neuro-2a cells were cultured for in vitro and transient middle cerebral artery occlusion model was used for in vivo studies to evaluate neuron targeting and anti-ischemic stroke potential of the sEVs-COCKTAIL. Bio-clickable sEVs were selectively taken up by neurons but not glial cells. In the in vitro ischemic stroke model of oxygen-glucose deprivation, the sEVs-COCKTAIL exhibited remarkable potential against reactive oxygen species and cellular apoptosis. In vivo studies further demonstrated the brain targeting and increased half-life of bio-clickable sEVs, delivering NR2B9c to the ischemic brain and reducing stroke injury. Treatment with the sEVs-COCKTAIL significantly increased behavioral recovery and reduced neuronal apoptosis after transient middle cerebral artery occlusion. NR2B9c was delivered to neurons binding to post-synaptic density protein-95, inhibiting N-methyl-d-Aspartate receptor-mediated over production of oxidative stress and mitigating protein B-cell lymphoma 2 and P38 proteins expression. Our results provide an efficient and biocompatible approach to a targeted delivery system, which is a promising modality for stroke therapy.

Plant exosome nanovesicles (PENs): green delivery platforms

Natural plants have been attracting increasing attention in biomedical research due to their numerous benefits. Plant exosome-derived vesicles, some of the plant's components, are small nanoscale vesicles secreted by plant cells. These vesicles are rich in bioactive substances and play significant roles in intercellular communication, information transfer, and maintaining homeostasis in organisms. They also hold promise for treating diseases, and their vesicular structures make them suitable carriers for drug delivery, with large-scale production feasible. Therefore, this paper aims to provide an overview of nanovesicles from different plant sources and their extraction methods. We also outline the biological activities of nanovesicles, including their anti-inflammatory, anti-viral, and anti-tumor properties, and systematically introduce their applications in drug delivery. These applications include transdermal delivery, targeted drug delivery, gene delivery, and their potential use in the modern food industry. This review provides new ideas and methods for future research on plant exosomes, including their empowerment by artificial intelligence and gene editing, as well as their potential application in the biomedicine, food, and agriculture industries.

Neural stem cell-derived extracellular vesicles: The light of central nervous system diseases

Central nervous system (CNS) diseases are the leading cause of death worldwide. By performing compensatory functions and improving the inflammatory microenvironment, the transplantation of neural stem cells (NSCs) can promote functional recovery from brain injury, aging, brain tumours, and other diseases. However, the ability of NSCs to differentiate into neurons is limited, and they are associated with a risk of tumourigenicity. NSC-derived extracellular vesicles (NSC-EVs) can modulate the local microenvironment of the nervous system as well as distant neuronal functions. Thus, cell-free therapy may be a novel remedy for CNS disorders. This article reviews the characteristics, contents, and mechanisms of action of NSC-EVs as well as their roles and application prospects in various CNS diseases.

Recent advances in lipid nanovesicles for targeted treatment of spinal cord injury

The effective regeneration and functional restoration of damaged spinal cord tissue have been a long-standing concern in regenerative medicine. Treatment of spinal cord injury (SCI) is challenging due to the obstruction of the blood-spinal cord barrier (BSCB), the lack of targeting of drugs, and the complex pathophysiology of injury sites. Lipid nanovesicles, including cell-derived nanovesicles and synthetic lipid nanovesicles, are highly biocompatible and can penetrate BSCB, and are therefore effective delivery systems for targeted treatment of SCI. We summarize the progress of lipid nanovesicles for the targeted treatment of SCI, discuss their advantages and challenges, and provide a perspective on the application of lipid nanovesicles for SCI treatment. Although most of the lipid nanovesicle-based therapy of SCI is still in preclinical studies, this low immunogenicity, low toxicity, and highly engineerable nanovesicles will hold great promise for future spinal cord injury treatments.

Extracellular vesicles: a rising star for therapeutics and drug delivery

Extracellular vesicles (EVs) are nano-sized, natural, cell-derived vesicles that contain the same nucleic acids, proteins, and lipids as their source cells. Thus, they can serve as natural carriers for therapeutic agents and drugs, and have many advantages over conventional nanocarriers, including their low immunogenicity, good biocompatibility, natural blood-brain barrier penetration, and capacity for gene delivery. This review first introduces the classification of EVs and then discusses several currently popular methods for isolating and purifying EVs, EVs-mediated drug delivery, and the functionalization of EVs as carriers. Thereby, it provides new avenues for the development of EVs-based therapeutic strategies in different fields of medicine. Finally, it highlights some challenges and future perspectives with regard to the clinical application of EVs.

Smartphone-based platforms implementing microfluidic detection with image-based artificial intelligence

The frequent outbreak of global infectious diseases has prompted the development of rapid and effective diagnostic tools for the early screening of potential patients in point-of-care testing scenarios. With advances in mobile computing power and microfluidic technology, the smartphone-based mobile health platform has drawn significant attention from researchers developing point-of-care testing devices that integrate microfluidic optical detection with artificial intelligence analysis. In this article, we summarize recent progress in these mobile health platforms, including the aspects of microfluidic chips, imaging modalities, supporting components, and the development of software algorithms. We document the application of mobile health platforms in terms of the detection objects, including molecules, viruses, cells, and parasites. Finally, we discuss the prospects for future development of mobile health platforms.

Stimuli-Responsive Gene Delivery Nanocarriers for Cancer Therapy

Gene therapy provides a promising approach in treating cancers with high efficacy and selectivity and few adverse effects. Currently, the development of functional vectors with safety and effectiveness is the intense focus for improving the delivery of nucleic acid drugs for gene therapy. For this purpose, stimuli-responsive nanocarriers displayed strong potential in improving the overall efficiencies of gene therapy and reducing adverse effects via effective protection, prolonged blood circulation, specific tumor accumulation, and controlled release profile of nucleic acid drugs. Besides, synergistic therapy could be achieved when combined with other therapeutic regimens. This review summarizes recent advances in various stimuli-responsive nanocarriers for gene delivery. Particularly, the nanocarriers responding to endogenous stimuli including pH, reactive oxygen species, glutathione, and enzyme, etc., and exogenous stimuli including light, thermo, ultrasound, magnetic field, etc., are introduced. Finally, the future challenges and prospects of stimuli-responsive gene delivery nanocarriers toward potential clinical translation are well discussed. The major objective of this review is to present the biomedical potential of stimuli-responsive gene delivery nanocarriers for cancer therapy and provide guidance for developing novel nanoplatforms that are clinically applicable.

Advances in extracellular vesicle functionalization strategies for tissue regeneration

Extracellular vesicles (EVs) are nano-scale vesicles derived by cell secretion with unique advantages such as promoting cell proliferation, anti-inflammation, promoting blood vessels and regulating cell differentiation, which benefit their wide applications in regenerative medicine. However, the in vivo therapeutic effect of EVs still greatly restricted by several obstacles, including the off-targetability, rapid blood clearance, and undesired release. To address these issues, biomedical engineering techniques are vastly explored. This review summarizes different strategies to enhance EV functions from the perspective of drug loading, modification, and combination of biomaterials, and emphatically introduces the latest developments of functionalized EV-loaded biomaterials in different diseases, including cardio-vascular system diseases, osteochondral disorders, wound healing, nerve injuries. Challenges and future directions of EVs are also discussed.