Surfactant-guided spatial assembly of nano-architectures for molecular profiling of extracellular vesicles

Deciphering the Dynamic Assembling-Disassembling of Small Molecules on Solid/Liquid Interfaces within Microchannels by Pulsed Streaming Potential Measurement

Assembling small molecules at liquid/solid interfaces is relatively common and contributes to many unique properties of the interface. However, such an assembling process can be dynamic depending on the concentration of the molecule and the properties of the solid and liquid themselves, which poses serious challenges on the accurate evaluation of the assembling processes. Herein, we report a convenient way for in situ and real-time monitoring of assembling-disassembling of small-molecule surfactants on the surface of microchannels using pulsed streaming potential (SP) measurement based on the variation of surface charge. With this technique, five distinctive kinetic regimes, each responsible for a characteristic molecular behavior, can be differentiated during a typical assembling-disassembling cycle. Significant difference of the assembling-disassembling process was clearly reflected for surfactants with hydrophobic tails of only a two -CH2- difference (C16TAB/C18TAB and D10DAB/D12DAB). The relative SP (Er) value is positively correlated with the molecular weight at a concentration of 0.1 mM for the same kinds of surfactants. Moreover, the assembling kinetics of D10DAB exhibits an "overshoot effect" at high concentration, which means morphology adjustment. The consequences of such assembling/disassembling of these molecules for electrophoretic separation, protein immobilization, and photocatalysis in a microchannel were investigated through dynamic characterization, which proves its potential as a tool for dynamic solid/liquid interface characterization.

Buoyant Metal-Organic Framework Corona-Driven Fast Isolation and Ultrasensitive Profiling of Circulating Extracellular Vesicles

Accurately assaying tumor-derived circulating extracellular vesicles (EVs) is fundamental in noninvasive cancer diagnosis and therapeutic monitoring but limited by challenges in efficient EV isolation and profiling. Here, we report a bioinspired buoyancy-driven metal-organic framework (MOF) corona that leverages on-bubble coordination and dual-encoded surface-enhanced Raman scattering (SERS) nanotags to streamline rapid isolation and ultrasensitive profiling of plasma EVs in a single assay for cancer diagnostics. This integrated bubble-MOF-SERS EV assay (IBMsv) allows barnacle-like high-density adhesion of MOFs on a self-floating bubble surface to enable fast isolation (2 min, near 90% capture efficiency) of tumor EVs via enhanced EV-MOF binding. Also, IBMsv harnesses four-plexed SERS nanotags to profile the captured EV surface protein markers at a single-particle level. Such a sensitive assay allows multiplexed profiling of EVs across five cancer types, revealing heterogeneous EV surface expression patterns. Furthermore, the IBMsv assay enables cancer diagnosis in a pilot clinical cohort (n = 55) with accuracies >95%, improves discrimination between cancer and noncancer patients via an algorithm, and monitors the surgical treatment response from hepatocellular carcinoma patients. This assay provides a fast, sensitive, streamlined, multiplexed, and portable blood test tool to enable cancer diagnosis and response monitoring in clinical settings.

Thermophoretic glycan profiling of extracellular vesicles for triple-negative breast cancer management

Triple-negative breast cancer (TNBC) is a highly metastatic and heterogeneous type of breast cancer with poor outcomes. Precise, non-invasive methods for diagnosis, monitoring and prognosis of TNBC are particularly challenging due to a paucity of TNBC biomarkers. Glycans on extracellular vesicles (EVs) hold the promise as valuable biomarkers, but conventional methods for glycan analysis are not feasible in clinical practice. Here, we report that a lectin-based thermophoretic assay (EVLET) streamlines vibrating membrane filtration (VMF) and thermophoretic amplification, allowing for rapid, sensitive, selective and cost-effective EV glycan profiling in TNBC plasma. A pilot cohort study shows that the EV glycan signature reaches 91% accuracy for TNBC detection and 96% accuracy for longitudinal monitoring of TNBC therapeutic response. Moreover, we demonstrate the potential of EV glycan signature for predicting TNBC progression. Our EVLET system lays the foundation for non-invasive cancer management by EV glycans.

An all-in-one portable colorimetric detection platform for sensitive detection of bisphenol A based on target-mediated CeO2@ZIF-8/Apt biocomposites

BPA aptamers functionalized cerium oxide nanoparticles encapsulated in zeolitic imidazolate framework-8 (CeO2@ZIF-8/Apt) were developed to fabricate an all-in-one portable platform for on-site quantitative detection of BPA. By combining biocomposites with a 3,3',5,5'-tetramethylbenzidine (TMB)-based sodium alginate (SA) hydrogel and smartphone-based RGB analysis, highly sensitive and convenient monitoring of BPA was achieved. CeO2@ZIF-8 composites were constructed using a novel surfactant-modified concentration-controlled synthesis strategy. After being functionalized with BPA aptamers, CeO2@ZIF-8/Apt biocomposites were used as target-response colorimetric probes for target recognition and signal transduction. The oxidase-like activity of CeO2@ZIF-8 was effectively sealed by BPA aptamers and controllably released in a concentration-dependent manner through aptamer-BPA reactions. Utilizing SA hydrogels containing TMB in the caps, a one-step sample addition and one-pot detection can be conveniently achieved and reliably quantified by smartphone-based RGB analysis in an instrument-free way. The detection range of this portable detection platform is 50 pg/mL to 500 ng/mL with limit of detection calculated as 34.88 pg/mL, comparable to that of conventional detection in the solution system (4.57 pg/mL). The recoveries in tap water, apple juice, and milk ranged from 91.02 % and 106.75 %. This work contributes new insights into the design of all-in-one detection platforms for contaminants monitoring in resource-constrained regions.

Magnetic nanoagent assisted deciphering of heterogeneous glycans in extracellular vesicles of varied cellular origins

Extracellular vesicles bear a rich glycome that presents versatile functions in diverse biological processes. Leverage polydopamine modified magnetic particles to serve as nanosized agents for rapid and robust EV capture and manipulation, we here integrated the easy magnetic actuation with specific lectin-glycan binding and enzyme-mediated fluorescence amplification and thus proposed a facile approach to efficiently decipher a broad spectrum of glycans in EVs. Termed magnetic nanoagent assisted extracellular vesicle glycan deciphering (MAEG), the developed assay utilized a magnet as the assistant operation tool and realized fast (∼1 h) and sensitive (a limit of detection of ∼0.7 μg/mL vesicles) EV glycan analysis in a simple low-cost (around 2.27 Chinese Yuan for one test) manner without requirement of any sophisticated platforms. With robust performance for different sample species, the assay achieved to depict the comprehensive glycosylation landscapes for varied EVs derived from eight cell lines focusing on non-small-cell lung cancer. Systematic analyses clearly revealed the high heterogeneity in glycan features of EVs of varied cellular origins. Using an established difference network method, unique glycan features in different EVs were sifted out and further compiled to construct lectin-denoted patterns as dedicated glycosylation fingerprints, potentially expanding EV-based clinical applications.

Dual-Recognition Triggered Proximity Ligation Combined with a Rolling Circle Amplification Strategy for Analysis of Exosomal Protein-Specific Glycosylation

Exosomal surface glycan reveals the biological function and molecular information on the protein, especially in indicating the pathogenesis of certain diseases through monitoring of specific protein glycosylation accurately. However, in situ and nondestructive measurement techniques for certain Exosomal glycoproteins are still lacking. In this work, combined with on-chip purification, we designed a proximity ligation assay-induced rolling circle amplification (RCA) strategy for highly sensitive identification of Exosomal protein-specific glycosylation based on a couple of proximity probes to target Exosomal protein and the protein-specific glycosylation site. Benefiting from efficient separation, scalable dual-recognition, and proximity-triggered RCA amplification, the proposed strategy could convert different protein-specific glycan levels to prominent changes in absorbance signals, resulting in accurate quantification of specific glycosylated Exosomal protein. When detecting the glycosylated PD-L1 on MDA-MB-231 exosomes and glycosylated PTK7 on HepG2 exosomes, the detection limits were calculated to be as low as 1.04 × 104 and 2.759 × 103 particles/mL, respectively. In addition, we further expand the dual-recognition site to investigate the potential correlation of Exosomal glycosylation with polarization of THP-1 cells toward the tumor-suppressive M1 phenotype. Overall, this strategy provides a universal tool for multiple analyses of diverse protein-specific glycosylated exosomes, exhibiting enormous potential to explore exosome function and search for new early diagnosis markers.

Precise Engineering of a Se/Te Nanochaperone for Reinvigorating Cancer Radio-Immunotherapy

Facilely synthesized nanoradiosensitizers with well-controlled structure and multifunctionality are greatly desired to address the challenges of cancer radiotherapy. In this work, a universal method is developed for synthesizing chalcogen-based TeSe nano-heterojunctions (NHJs) with rod-, spindle-, or dumbbell-like morphologies by engineering the surfactant and added selenite. Interestingly, dumbbell-shaped TeSe NHJs (TeSe NDs) as chaperone exhibit better radio-sensitizing activities than the other two nanostructural shapes. Meanwhile, TeSe NDs can serve as cytotoxic chemodrugs that degrade to highly toxic metabolites in acidic environment and deplete GSH within tumor to facilitate radiotherapy. More importantly, the combination of TeSe NDs with radiotherapy significantly decreases regulatory T cells and M2-phenotype tumor-associated macrophage infiltrations within tumors to reshape the immunosuppressive microenvironment and induce robust T lymphocytes-mediated antitumor immunity, resulting in great abscopal effects on combating distant tumor progression. This study provides a universal method for preparing NHJ with well-controlled structure and developing nanoradiosensitizers to overcome the clinical challenges of cancer radiotherapy.

Multiplexed RNA profiling by regenerative catalysis enables blood-based subtyping of brain tumors

Current technologies to subtype glioblastoma (GBM), the most lethal brain tumor, require highly invasive brain biopsies. Here, we develop a dedicated analytical platform to achieve direct and multiplexed profiling of circulating RNAs in extracellular vesicles for blood-based GBM characterization. The technology, termed 'enzyme ZIF-8 complexes for regenerative and catalytic digital detection of RNA' (EZ-READ), leverages an RNA-responsive transducer to regeneratively convert and catalytically enhance signals from rare RNA targets. Each transducer comprises hybrid complexes - protein enzymes encapsulated within metal organic frameworks - to configure strong catalytic activity and robust protection. Upon target RNA hybridization, the transducer activates directly to liberate catalytic complexes, in a target-recyclable manner; when partitioned within a microfluidic device, these complexes can individually catalyze strong chemifluorescence reactions for digital RNA quantification. The EZ-READ platform thus enables programmable and reliable RNA detection, across different-sized RNA subtypes (miRNA and mRNA), directly in sample lysates. When clinically evaluated, the EZ-READ platform established composite signatures for accurate blood-based GBM diagnosis and subtyping.

Surface ligand-assisted synthesis and biomedical applications of metal-organic framework nanocomposites

Metal-organic framework (MOF) nanocomposites have recently gained intensive attention for biosensing and disease therapy applications owing to their outstanding physiochemical properties. However, the direct growth of MOF nanocomposites is usually hindered by the mismatched lattice in the interface between the MOF and other nanocomponents. Surface ligands, molecules with surfactant-like properties, are demonstrated to exhibit the robust capability to modify the interfacial properties of nanomaterials and can be utilized as a powerful strategy for the synthesis of MOF nanocomposites. Besides this, surface ligands also exhibit significant functions in the morphological control and functionalization of MOF nanocomposites, thus greatly enhancing their performance in biomedical applications. In this review, the surface ligand-assisted synthesis and biomedical applications of MOF nanocomposites are comprehensively reviewed. Firstly, the synthesis of MOF nanocomposites is discussed according to the diverse roles of surface ligands. Then, MOF nanocomposites with different properties are listed with their applications in biosensing and disease therapy. Finally, current challenges and further directions of MOF nanocomposites are presented to motivate the development of MOF nanocomposites with elaborate structures, enriched functions, and excellent application prospects.

An Ion-Engineering Strategy to Design Hollow FeCo/CoFe2 O4 Microspheres for High-Performance Microwave Absorption

Although assembled hollow architectures have received considerable attention as lightweight functional materials, their uncontrollable self-aggregation and tedious synthetic methods hinder precise construction and modulation. Therefore, this study proposes a bi-ion synergistic regulation strategy to design assembled hollow-shaped cobalt spinel oxide microspheres. Dominated by the coordination-etching effects of F^- and the hydrolysis-complex contributions of NH₄ ⁺ , the unique construction is formed attributed to the dynamic cycles between metal complexes and precipitates. Meanwhile, their basic structures are perfectly retained after reduction treatment, enabling FeCo/CoFe₂ O₄ bimagnetic system to be obtained. Subsequently, in-depth analyses are conducted. Investigations reveal that multiscale magnetic coupling networks and enriched air-material heterointerfaces contribute to the remarkable magnetic-dielectric behavior, supported by the advanced off-axis electron holography technique. Consequently, the obtained FeCo/CoFe₂ O₄ composites exhibit excellent microwave absorption performances with minimal reflection losses (RL_min ) as high as -51.6 dB, an effective absorption bandwidth (EAB) of 4.7 GHz, and a matched thickness of 1.4 mm. Thus, this work provides an informative guide for rationally assembling building blocks into hollow architectures as advanced microwave absorbers through bi-ion and even multi-ion synergistic engineering mechanisms.

Synthesis and characterization of selenium nanoparticles stabilized with cocamidopropyl betaine

In this work, selenium nanoparticles (Se NPs) stabilized with cocamidopropyl betaine were synthesized for the first time. It was observed that Se NPs synthesized in excess of selenic acid had a negative charge with ζ-potential of -21.86 mV, and in excess of cocamidopropyl betaine-a positive charge with ξ =  + 22.71 mV. The resulting Se NPs with positive and negative charges had a spherical shape with an average size of about 20-30 nm and 40-50 nm, respectively. According to the data of TEM, HAADF-TEM using EDS, IR spectroscopy and quantum chemical modeling, positively charged selenium nanoparticles have a cocamidopropylbetaine shell while the potential- forming layer of negatively charged selenium nanoparticles is formed by SeO₃^2- ions. The influence of various ions on the sol stability of Se NPs showed that SO₄^2- and PO₄^3- ions had an effect on the positive Se NPs, and Ba²⁺ and Fe³⁺ ions had an effect on negative Se NPs, which corresponded with the Schulze-Hardy rule. The mechanism of coagulating action of various ions on positive and negative Se NPs was also presented. Also, influence of the active acidity of the medium on the stability of Se NPs solutions was investigated. Positive and negative sols of Se NPs had high levels of stability in the considered range of active acidity of the medium in the range of 1.21-11.98. Stability of synthesized Se NPs stability has been confirmed in real system (liquid soap). An experiment with the addition of Se NPs stabilized with cocamidopropyl betaine to liquid soap showed that the particles of dispersed phases retain their initial distributions, which revealed the stability of synthesized Se NPs.

Biomimetic 3D Recognition with 2D Flexible Nanoarchitectures for Ultrasensitive and Visual Extracellular Vesicle Detection

Despite increasing recognition of extracellular vesicles being important circulating biomarkers in disease diagnosis and prognosis, current strategies for extracellular vesicle detection remain limited due to the compromised sample purification and extensive labeling procedures in complex body fluids. Here, we developed a 2D magnetic platform that greatly improves capture efficiency and readily realizes visible signal conversion for extracellular vesicle detection. The technology, termed high-affinity recognition and visual extracellular vesicle testing (HARVEST), leverages 2D flexible Fe₃O₄-MoS₂ nanostructures to recognize extracellular vesicles through multidentate affinity binding and feasible magnetic separation, thus enhancing the extracellular vesicle capture performance with both yield and separation time, affording high sensitivity with the detection limit of 20 extracellular vesicle particles/μL. Through integration with lipid labeling chemistry and the fluorescence visualization system, the platform enables rapid and visible detection. The number of extracellular vesicles can be feasibly determined by smart mobile phones, readily adapted for point-of-care diagnosis. When clinically evaluated, the strategy accurately differentiates melanoma samples from the normal cohort with an AUC of 0.98, demonstrating the efficient extracellular vesicle detection strategy with 2D flexible platforms for cancer diagnosis.

A Designed Twist Sensor Based on the SPR Effect in the Thin-Gold-Film-Coated Helical Microstructured Optical Fibers

The traditional optical fiber-based twist sensing has the disadvantage of low sensitivity and difficulty of distinguishing the twist direction. Moreover, chiral isomerism may lead to sensing errors. In this paper, a six-hole helical microstructured optical fiber (HMSF) with a thin-gold-film-coat based on the surface plasmon resonance (SPR) effect was designed. The twist sensing characteristics of this fiber were further analyzed. Numerical calculation and analysis show that the combination of helical effect and SPR effect can design an HMSF-based sensor that is very sensitive to distortion. In the torsion range of ±300°, the distortion sensitivity can reach 2470.7 pm/(rad/m), and the linear correlation coefficient is 0.99996. Based on the special sensing mechanism, it has a good linear coefficient over a large range. Additionally, the direction of the twist can be easily discerned. The HMSF in this work not only has high sensitivity, high linearity, high fault tolerance rate, and a wide range of measurement, but is also easy to manufacture. Therefore, it is promising in the field of twist sensing and has a good application prospect.