Review of the advances in lipid anchors-based biosensors for the isolation and detection of exosomes

Computational studies for the development of extracellular vesicle-based biosensors

Cancer affects millions of people, and early detection and efficient treatment are two strong levers to hurdle this disease. Recent studies on exosomes, a subset of extracellular vesicles, have deliberately shown the potential to function as a biomarker or treatment tool, thereby attracting the attention of researchers who work on developing biosensors. Due to the ability of computational methods to predict of the behavior of biomolecules, the combination of experimental and computational methods would enhance the analytical performance of the biosensor, including sensitivity, accuracy, and specificity, even detecting such vesicles from bodily fluids. In this regard, the role of computational methods such as molecular docking, molecular dynamics simulation, and density functional theory is overviewed in the development of biosensors. This review highlights the investigations and studies that have been reported using these methods to design exosome-based biosensors. This review concludes with the role of the quantum mechanics/molecular mechanics method in the investigation of chemical processes of biomolecular systems and the deficiencies in using this approach to develop exosome-based biosensors. In addition, the artificial intelligence theory is explained briefly to show its importance in the study of these biosensors.

Emerging phospholipid-targeted affinity materials for extracellular vesicle isolation and molecular profiling

Extracellular vesicles (EVs) carrying lipids, proteins, nucleic acids and small molecular metabolites have emerged as an attractive paradigm for understanding and interfering physiological and pathological processes. To this end, selective and efficient separation approaches are highly demanded to obtain target EVs from complicated biosamples. With increasing knowledges on EV lipids, recent years have witnessed rapid advances of phospholipid-targeted affinity materials and platforms for high-performance isolation and analysis of EVs. In view of this, this review is contributed to introduce recent progresses in lipid membrane-targeted affinity strategies for EV isolation and molecular detection in biofluids. Affinity ligands including lipids, peptides, small molecules and aptamers and their molecular interactions with lipids are discussed in focus. The design, construction and mechanism of actions of affinity interfaces are summarized. The EV separation performances in complex biosamples and downstream proteomic, lipidomic and metabolic profiling are introduced. Finally, the perspectives and challenges for the development of next-generation phospholipid-targeted EV separation platforms are discussed.

Novel biomimetic hybrid plasmonic nanocavity-based ECL strategy for the detection of extracellular vesicles

Tumor-derived extracellular vesicles detection has emerged as an important clinical liquid biopsy approach for cancer diagnosis. In this work, we developed a novel hybrid plasmonic nanocavity consisting of hexagonal Au nanoplates nanoarray, SnS2/Au nanosheet layer and biomimetic lipid bilayer. Firstly, the hybrid plasmonic nanocavity combined the optical confinement for the ECL regulation and the biological recognition for the detection of extracellular vesicles. Secondly, MXene-derived Ti2N QDs have been prepared as ECL nanoprobe to label extracellular vesicles. Moreover, biomimetic lipid bilayer with specific aptamer was used to identify extracellular vesicles and integrate Ti2N QDs into the nanocavity with membrane fusion strategy. Due to the significant electromagnetic field enhancement at the cavity region, the hybrid plasmonic nanocavity provided strong field confinement to concentrate and redistribute the ECL emission of QDs with a 9.3-fold enhancement. The hybrid plasmonic nanocavity-based ECL sensing system improved the spatial controllability of EVs analysis and the accurate resolution of specific protein. It achieved the sensitive detection of extracellular vesicles in ascites and successfully distinguished the peritoneal metastasis of gastric cancer.

Functional Three-Dimensional Zeolitic Imidazolate Framework with an Ordered Macroporous Structure for the Isolation of Extracellular Vesicles

Extracellular vesicles (EVs) and their cargoes are increasingly being recognized as noninvasive diagnostic markers, necessitating the isolation of EVs from complex biological samples. Herein, a distearoyl phospholipid ethanolamine-functionalized single-crystal ordered macroporous three-dimensional zeolitic imidazolate framework (SOM-ZIF-8-DSPE) was developed, which combines the surface charge interaction of ZIF-8 with the synergistic effect of DSPE insertion into the phospholipid membrane of EVs to improve the isolating selectivity of EV capture. The materials have porous structures larger than 300 nm in diameter, providing enough space and active sites to trap EVs. Benefiting from this feature, the entire isolation process takes only 10 min and is well compatible with the subsequent analysis of RNA in EVs. Consequently, 10 upregulated miRNA of plasma EVs in the primary colorectal cancer (pCRC) patients is found over the healthy donors, and 6 upregulated miRNA of plasma EVs in the metastatic colorectal cancer (mCRC) patients over pCRC patients. These findings suggest that the isolation of EV-based SOM-ZIF-8-DSPE is a promising strategy to identify biomarkers for disease diagnosis, such as miRNAs in plasma EVs for the early detection of CRC.

Extracellular Vesicle Preparation and Analysis: A State-of-the-Art Review

In recent decades, research on Extracellular Vesicles (EVs) has gained prominence in the life sciences due to their critical roles in both health and disease states, offering promising applications in disease diagnosis, drug delivery, and therapy. However, their inherent heterogeneity and complex origins pose significant challenges to their preparation, analysis, and subsequent clinical application. This review is structured to provide an overview of the biogenesis, composition, and various sources of EVs, thereby laying the groundwork for a detailed discussion of contemporary techniques for their preparation and analysis. Particular focus is given to state-of-the-art technologies that employ both microfluidic and non-microfluidic platforms for EV processing. Furthermore, this discourse extends into innovative approaches that incorporate artificial intelligence and cutting-edge electrochemical sensors, with a particular emphasis on single EV analysis. This review proposes current challenges and outlines prospective avenues for future research. The objective is to motivate researchers to innovate and expand methods for the preparation and analysis of EVs, fully unlocking their biomedical potential.

A comprehensive review of engineered exosomes from the preparation strategy to therapeutic applications

Exosomes exhibit high bioavailability, biological stability, targeted specificity, low toxicity, and low immunogenicity in shuttling various bioactive molecules such as proteins, lipids, RNA, and DNA. Natural exosomes, however, have limited production, targeting abilities, and therapeutic efficacy in clinical trials. On the other hand, engineered exosomes have demonstrated long-term circulation, high stability, targeted delivery, and efficient intracellular drug release, garnering significant attention. The engineered exosomes bring new insights into developing next-generation drug delivery systems and show enormous potential in therapeutic applications, such as tumor therapies, diabetes management, cardiovascular disease, and tissue regeneration and repair. In this review, we provide an overview of recent advancements associated with engineered exosomes by focusing on the state-of-the-art strategies for cell engineering and exosome engineering. Exosome isolation methods, including traditional and emerging approaches, are systematically compared along with advancements in characterization methods. Current challenges and future opportunities are further discussed in terms of the preparation and application of engineered exosomes.

Improving Pharmacokinetics of Peptides Using Phage Display

Phage display is a versatile method often used in the discovery of peptides that targets disease-related biomarkers. A major advantage of this technology is the ease and cost efficiency of affinity selection, also known as biopanning, to identify novel peptides. While it is relatively straightforward to identify peptides with optimal binding affinity, the pharmacokinetics of the selected peptides often prove to be suboptimal. Therefore, careful consideration of the experimental conditions, including the choice of using in vitro, in situ, or in vivo affinity selections, is essential in generating peptides with high affinity and specificity that also demonstrate desirable pharmacokinetics. Specifically, in vivo biopanning, or the combination of in vitro, in situ, and in vivo affinity selections, has been proven to influence the biodistribution and clearance of peptides and peptide-conjugated nanoparticles. Additionally, the marked difference in properties between peptides and nanoparticles must be considered. While peptide biodistribution depends primarily on physiochemical properties and can be modified by amino acid modifications, the size and shape of nanoparticles also affect both absorption and distribution. Thus, optimization of the desired pharmacokinetic properties should be an important consideration in biopanning strategies to enable the selection of peptides and peptide-conjugated nanoparticles that effectively target biomarkers in vivo.

Advances in colorimetric biosensors of exosomes: novel approaches based on natural enzymes and nanozymes

Exosomes are 30-150 nm vesicles derived from diverse cell types, serving as one of the most important biomarkers for early diagnosis and prognosis of diseases. However, the conventional detection method for exosomes faces significant challenges, such as unsatisfactory sensitivity, complicated operation, and the requirement of complicated devices. In recent years, colorimetric exosome biosensors with a visual readout underwent rapid development due to the advances in natural enzyme-based assays and the integration of various types of nanozymes. These synthetic nanomaterials show unique physiochemical properties and catalytic abilities, enabling the construction of exosome colorimetric biosensors with novel principles. This review will illustrate the reaction mechanisms and properties of natural enzymes and nanozymes, followed by a detailed introduction of the recent advances in both types of enzyme-based colorimetric biosensors. A comparison between natural enzymes and nanozymes is made to provide insights into the research that improves the sensitivity and convenience of assays. Finally, the advantages, challenges, and future directions of enzymes as well as exosome colorimetric biosensors are highlighted, aiming at improving the overall performance from different approaches.

Research Advances of Engineered Exosomes as Drug Delivery Carrier

Exosomes are nanoscale vesicles secreted by living cells that have similar membrane composition to parental cells and carry a variety of proteins, lipids, and nucleic acids. Therefore, exosomes have certain biological activities and play an important role in intercellular communication. On the basis of its potential as a carrier for drug delivery systems, exosomes have been engineered to compensate for the shortage of natural exosomes through various engineering strategies for improving drug delivery efficiency, enhancing targeting to tissues and organs, and extending the circulating half-life of exosomes. This review focuses on the engineered exosomes loading drugs through different strategies, discussions on exosome surface modification strategies, and summarizes the advantages and disadvantages of different strategies. In addition, this review provides an overview of the recent applications of engineered exosomes in a number of refractory and relapsable diseases. This review has the potential to provide a reference for further research and development of engineered exosomes.

Unraveling the Molecular Dynamics of Glucose Oxidase Desorption Induced by Argon Cluster Collision

The bombardment of a protein multilayer target by an energetic argon cluster ion beam enables protein transfer onto a collector in the vacuum while preserving their bioactivity (iBEAM method). In parallel to this new soft-landing variant, protein transfer in the gas phase is a prerequisite for their characterization by mass spectrometry. The successful transfer of bioactive lysozymes (14 kDa) by cluster-induced soft landing and its mechanistic explanation by molecular dynamics (MD) simulations have sparked an important inquiry: Can heavier biomolecules be desorbed while maintaining their tridimensional structure and hence their bioactivity? To address this question, we employed MD simulations using a reactive force field (ReaxFF). Specifically, the Ar cluster-induced desorption of glucose oxidase from either a gold substrate or a lysozyme underlayer was modeled using the LAMMPS code. First, the force field parameters were trained by computing the dissociation energetics of a series of organic molecules with ReaxFF and DFT, in order to realistically describe N-S and O-S interactions in the bombarded glucose oxidase molecule. Second, bombardment simulations investigated the effects of cluster size (ranging from 1000 to 10000 Ar atoms) and kinetic energy (1.5 and 3.0 eV/atom) on the structural features and energetics of the desorbing glucose oxidase. Our results show that large argon clusters (≥7000) are needed to desorb glucose oxidase from a gold surface, yet protein fragmentation and/or pronounced denaturation occur. However, the transfer of structurally preserved glucose oxidase in the gas phase is predicted by the simulations when an organic layer is used as a substrate.