Development of Integrin-Facilitated Bispecific Aptamer Chimeras for Membrane Protein Degradation.

The emergence of lysosome-targeting chimeras (LYTACs), which represents a promising strategy for membrane protein degradation based on lysosomal pathways, has attracted much attention in disease intervention and treatment. However, the expression level of commonly used lysosome-targeting receptors (LTRs) varies in different cell lines, thus limiting the broad applications of LYTACs. To overcome this difficulty, we herein report the development of integrin α3ß1 (ITGA3B1)-facilitated bispecific aptamer chimeras (ITGBACs) as a platform for the degradation of membrane proteins. ITGBACs consist of two aptamers, one targeting ITGA3B1 and another binding to the membrane-associated protein of interest (POI), effectively transporting the POI into lysosomes for degradation. Our findings demonstrate that ITGBACs effectively eliminate pathological membrane proteins, such as CD71 and PTK7, inducing significant cell-cycle arrest and apoptosis and markedly inhibiting tumor growth in tumor-bearing mice models. Therefore, this work provides a novel and versatile membrane protein degradation platform, offering a promising targeted therapy based on tumor-specific LTRs.

Dimensional regulation of lanthanide metal-organic frameworks and their application in bacterial detection.

Low-dimensional (LD) lanthanide metal-organic frameworks (Ln-MOFs) have attracted considerable attention in different fields due to their exceptional optical properties and numerous accessible active sites. Through the dimensional regulation effect of dipicolinic acid (DPA), a new LD Ln-MOF crystal is synthesized to monitor nitroreductase (NTR) activity in living bacteria.

Highly efficient removal and real-time visual detection of fluoride ions using ratiometric CAU-10-NH2@RhB: Probe design, sensing performance, and practical applications.

The extensive use of fluoride in agriculture, industry, medicine, and daily necessities has raised growing concerns about fluoride residue. To date, real-time visual detection and efficient removal of fluoride ions from water remain greatly desirable. Herein, nano-CAU-10-NH2@RhB is introduced as a ratiometric fluorescent probe and efficient scavenger for the intelligent detection and removal of fluoride ions. CAU-10-NH2@RhB is readily obtained through one-pot synthesis and exhibits high sensitivity and selectivity for real-time fluoride ion detection, with a naked-eye distinguishable color change from pink to blue. A portable device for point-of-care testing was developed based on color hue analysis readout using a smartphone. A quantitative response was achieved across a wide concentration range, with a detection limit of 54.2 nM. Adsorption experiments suggest that nano-CAU-10-NH2@RhB serves as an efficient fluoride ion scavenger, with a fluoride adsorption capacity of 49.3 mg/g. Moreover, the mechanistic study revealed that hydrogen bonds formed between fluoride ions and amino groups of CAU-10-NH2@RhB are crucial for the detection and adsorption of fluoride ions. This analysis platform was also used for point-of-care quantitative visual detection of fluoride ions in food, water, and toothpaste.

Regulating Arrhenius Activation Energy and Fluorescence Quantum Yields of AuNCs-MOF to Achieve High Temperature Sensitivity in a Wide Response Window.

Luminescent thermometry affords remote measurement of temperature and shows huge potential in future technology beyond those possible with traditional methods. Strategies of temperature measurement aiming to increase thermal sensitivity in a wide temperature response window would represent a pivotal step forward, but most thermometers cannot do both of them. Herein, we propose a balancing strategy to achieve a trade-off between high Arrhenius activation energy (Ea), which could stretch the temperature response windows, and fluorescence quantum yields (QYs) in a manner that will increase thermal sensitivity in a wide response window. In particular, a luminescent thermometer composed of AuNCs-MOF is prepared via a facile impregnation process to enhance QYs and Ea, responsible for high relative sensitivity (Sr) (15.6% K-1) and ultrawide temperature linearity range (from 83 to 343 K), respectively. Taking fluorescence intensity and lifetime as multiple parameters, the maximum Sr can reach 22.4% K-1 by multiple linear regression. The maximum Sr and temperature response range of the proposed thermometer outperform those of the most recent luminescent thermometers. The strategy of balancing Sr and thermal response range by regulating Ea and QYs enables the construction of ultra-accurate thermal sensors in the age of artificial intelligence.

Twisted Intramolecular Charge Transfer-Based Viscosity-Responsive Probe Reveals Lysosomal Degradation Process of Endocytosed Foreign Bodies.

The optimization of nanomedicines requires a thorough understanding of nanocarrier attrition during lysosome-mediated biological processes. Real-time monitoring of endocytosis provides valuable insights into the lysosomal effects on nanocarriers and the release of nanodrugs. We report the development of a coresponsive probe that detects changes in the spatial viscosity of the intracellular domain caused by lysosomal degradation of foreign bodies. The probe, based on a benzofuro[2,3-d]pyrimidine structure, exhibits torsional intramolecular charge transfer (TICT) and responds to ambient viscosity changes with a sensitive fluorescence intensity. The antidiffused fluorescence transition of the probe in the spatially restricted domain serves as a key indicator for real-time monitoring. When encapsulated with diverse foreign bodies and emitted into macrophages by endocytosis, the probe forms nanoparticles. Lysosomes uptake these materials for intracellular digestion, causing alterations in the aggregation or depolymerization state of the nanoparticles, leading to viscosity changes manifested by the probe's fluorescence. By studying the spatial viscosity changes caused by lysosomal degradation of foreign bodies, our monitoring strategy contributes to understanding the digestion or escape capabilities of potential pharmaceutical-carrying nanocarriers, providing guidelines to design more effective nanocarriers that navigate lysosomal degradation to achieve precise drug payloads and release.

Empowering Exosomes with Aptamers for Precision Theranostics.

As information messengers for cell-to-cell communication, exosomes, typically small membrane vesicles (30-150 nm), play an imperative role in the physiological and pathological processes of living systems. Accumulating studies have demonstrated that exosomes are potential biological candidates for theranostics, including liquid biopsy-based diagnosis and drug delivery. However, their clinical applications are hindered by several issues, especially their unspecific detection and insufficient targeting ability. How to upgrade the accuracy of exosome-based theranostics is being widely explored. Aptamers, benefitting from their admirable characteristics, are used as excellent molecular recognition elements to empower exosomes for precision theranostics. With high affinity against targets and easy site-specific modification, aptamers can be incorporated with platforms for the specific detection of exosomes, thus providing opportunities for advancing disease diagnostics. Furthermore, aptamers can be tailored and functionalized on exosomes to enable targeted therapeutics. Herein, this review emphasizes the empowering of exosomes by aptamers for precision theranostics. A brief introduction of exosomes and aptamers is provided, followed by a discussion of recent progress in aptamer-based exosome detection for disease diagnosis, and the emerging applications of aptamer-functionalized exosomes for targeted therapeutics. Finally, current challenges and opportunities in this research field are presented.

Integrating a Copper-Histidine Brace in a Mimetic Nanozyme Streamlines the Tyrosinase Recognition Moiety to Achieve Chiral Differentiation.

Designing artificial mimetic enzymes with high activity/selectivity to replace chiral bioenzymes is of great interest in the development of chiral materials consisting of molecules, enantiomers, that exist in two forms as mirror images of one another but cannot be superimposed. In this study, the chiral catalytic structural unit was streamlined from tyrosinase to integrate a mimetic nanozyme. The chiral amino acid l-histidine, as the chiral binding/recognition site, and the active metal site Cu were coupled (Cu@l-His) to create a copper-histidine brace with enantioselective catalytic ability to tyrosinol enantiomers. Results of kinetic parameters and activation energies confirmed the excellent peroxidase-like activity with a preference of Cu@l-His to l-tyrosinol. Such a preference could be attributed to the structurally oriented copper-histidine brace with a stronger affinity and catalytic activity to l-tyrosinol. By accurately evaluating chiral recognition units derived from bioenzymes, stable and superior chiral mimetic nanoenzymes could be constructed in a more straightforward and simplified manner, and they could also be extended to the reconstruction of diverse chiral enzymes.

Fabrication and Characterization of Microneedle Patches for Loading and Delivery of Exosomes.

Exosomes, as emerging "next-generation" biotherapeutics and drug delivery vectors, hold immense potential in diverse biomedical fields, ranging from drug delivery and regenerative medicine to disease diagnosis and tumor immunotherapy. However, the rapid clearance by traditional bolus injection and poor stability of exosomes restrict their clinical application. Microneedles serve as a solution that prolongs the residence time of exosomes at the administration site, thereby maintaining the drug concentration and facilitating sustained therapeutic effects. In addition, microneedles also possess the ability to maintain the stability of bioactive substances. Therefore, we introduce a microneedle patch for loading and delivering exosomes and share the methods, including isolation of exosomes, fabrication, and characterization of exosome-loaded microneedle patches. The microneedle patches were fabricated using trehalose and hyaluronic acid as the tip materials and polyvinylpyrrolidone as the backing material through a two-step casting method. The microneedles demonstrated robust mechanical strength, with tips able to withstand 2 N. Pig skin was used to simulate human skin, and the tips of microneedles completely melted within 60 s after skin puncture. The exosomes released from the microneedles exhibited morphology, particle size, marker proteins, and biological functions comparable to those of fresh exosomes, enabling dendritic cells uptake and promoting their maturation.

Fabrication of a two-dimensional bi-lanthanide metal-organic framework as a ratiometric fluorescent sensor based on energy competition.

Bimetallic lanthanide metal-organic frameworks (bi-Ln-MOFs) exhibit great appeal for ratiometric luminescent sensors due to their unique advantages. Specially, the low-lying energy of the empty 4f band of Ce4+ ions benefits Ce-MOFs with robust and broad fluorescent emission. Therefore, constructing ratiometric sensors based on Ce-MOFs is of significance but remains a challenge. Here, a two-dimensional (2D) bi-Ln-MOF is fabricated using Eu3+/Ce4+ and 5-boronoisophthalic acid (5-bop) via a crystal phase transformation strategy to construct a ratiometric luminescent Hg2+ sensor. Due to the lower energy gap of Ce4+ compared to Eu3+ and the corresponding stronger energy-absorption ability, the Ce4+ in bi-Ln-MOF shows a stronger and broader fluorescent emission than that of Eu3+. The substitution of the boric acid group in the bi-Ln-MOF by Hg2+ amplifies the difference between the two lanthanide ions. Therefore, the fluorescence intensity of Ce4+ increases whereas that of Eu3+ decreases accordingly, a behavior distinct from individual Eu-MOF or Ce-MOF performance. This novel bi-Ln-MOF sensor not only achieves a wide linear response range from 0.5 to 120 µM with a low detection limit of 167 nM for Hg2+, but also demonstrates exceptional selectivity and stability. The intriguing sensing mechanism of energy competition and the novel synthesis approach for 2D bi-Ln-MOF are anticipated to broaden the application possibilities of bi-Ln-MOFs for designing ratiometric sensors.

Dual-Aptamer Recognition of DNA Logic Gate Sensor-Based Specific Exosomal Proteins for Ovarian Cancer Diagnosis.

Clinical diagnosis of ovarian cancer lacks high accuracy due to the weak selection of specific biomarkers along with the circumstance biomarkers localization. Clustering analysis of proteins transported on exosomes enables a more precise screening of effective biomarkers. Herein, through bioinformatics analysis of ovarian cancer and exosome proteomes, two coexpressed proteins, EpCAM and CD24, specifically enriched, were identified, together with the development of an as-derived dual-aptamer targeted exosome-based strategy for ovarian cancer screening. In brief, a DNA ternary polymer with aptamers targeting EpCAM and CD24 was designed to present a logic gate reaction upon recognizing ovarian cancer exosomes, triggering a rolling circle amplification chemiluminescent signal. A dynamic detection range of 6 orders of magnitude was achieved by quantifying exosomes. Moreover, for clinical samples, this strategy could accurately differentiate exosomes from healthy persons, other cancer patients, and ovarian cancer patients, enabling promising in situ detection. By accurately selecting biomarkers and constructing a dual-targeted exosomal protein detection strategy, the limitation of insufficient specificity of traditional protein markers was circumvented. This work contributed to the development of exosome-based prognosis monitoring in ovarian cancer through the identification of disease-specific exosome protein markers.

Rapid Correction of the Hypoglycemia State in Nonhuman Primates Using a Glucagon Long-Dissolving Microneedle Patch.

The timely administration of glucagon is a standard clinical practice for the treatment of severe hypoglycemia. However, the process involves cumbersome steps, including the reconstitution of labile glucagon and filling of the syringe, which cause considerable delays in emergency situations. Moreover, multiple dosages are often required to prevent the recurrence of the hypoglycemic episode because of the short half-life of glucagon in plasma. Herein, we develop a glucagon-loaded long-dissolving microneedle (GLMN) patch that exhibits the properties of fast onset and sustained activity for the effective treatment of severe hypoglycemia. Three types of MN patches were fabricated with different dimensions (long, medium, and short). The longer MN patch packaged a higher dosage of glucagon and exhibited supreme mechanical strength compared to the shorter one. Additionally, the longer MN patch could insert more deeply into the skin, resulting in higher permeability of glucagon across the skin tissue and more rapid systemic absorption as compared with the shorter MN patch. The GLMN patch was observed to reverse the effects of hypoglycemia within 15 min of application in animal models (specifically, rat and rhesus monkey models) and maintained long-term glycemic control, owing to highly efficient drug permeation and the drug reservoir effect of the MN base. The current study presents a promising strategy for the rapid reversal of severe hypoglycemia that exhibits the desirable properties of easy use, high efficiency, and sustained action.

Metal-organic framework-based ratiometric point-of-care testing for quantitative visual detection of nitrite.

Nitrite (NO2-) is categorized as a carcinogenic substance and is subjected to severe limitations in water and food. To safeguard the public's health, developing fast and convenient methods for determination of NO2- is of significance. Point-of-care testing (POCT) affords demotic measurement of NO2- and shows huge potential in future technology beyond those possible with traditional methods. Here, a novel ratiometric fluorescent nanoprobe (Ru@MOF-NH2) is developed by integrating UiO-66-NH2 with tris(2,2'-bipyridyl)ruthenium(II) ([Ru(bpy)3]2+) through a one-pot approach. The special diazo-reaction between the amino group of UiO-66-NH2 and NO2- is responsible for the report signal (blue emission) with high selectivity and the red emission from [Ru(bpy)3]2+ offers the reference signal. The proposed probe shows obviously distinguishable color change from blue to red towards NO2- via naked-eye. Moreover, using a smartphone as the detection device to read color hue, ultra-sensitive quantitative detection of NO2- is achieved with a low limit of detection at 0.6 µΜ. The accuracy and repeatability determined in spiked samples through quantitative visualization is in the range of 105 to 117% with a coefficient of variation below 4.3%. This POCT sensing platform presents a promising strategy for detecting NO2- and expands the potential applications for on-site monitoring in food and environment safety assessment.

An ATMND/SGI based three-way junction ratiometric fluorescent probe for rapid and sensitive detection of bleomycin.

In this work, we developed a rapid and sensitive label-free ratiometric fluorescent (FL) probe for the detection of bleomycin (BLM). The probe consists of a DNA sequence (D6) and two fluorophore groups, 2-amino-5,6,7-trimethyl-1,8-naphthalene (ATMND) and SYBR Green I (SGI). The D6 sequence could be folded into a three-way junction structure containing a C-C mismatch position in the junction pocket. The unique "Y" structure not only could entrap ATMND in the mismatch pocket with high affinity, leading to FL quenching at 408 nm, but also embed SGI in the grooves of the double-stranded portion, resulting in FL enhancement at 530 nm. In the presence of BLM-Fe(II), the "Y" structure of D6 was destroyed due to the specific cleavage of the BLM recognition site, the 5'-GT-3' site in D6. This caused the release of ATMND and SGI and thus the ratiometric signal change of FL enhancement by ATMND and FL quenching by SGI. Under optimal conditions, the ratiometric probe exhibited a linear correlation between the intensity ratio of F408/F530 and the concentration of BLM in the range of 0.5-1000 nM, with a detection limit of 0.2 nM. In addition, the probe was applied to detect BLM in human serum samples with satisfactory results, indicating its good clinical application potential.

An Ultraswelling Microneedle Device for Facile and Efficient Drug Loading and Transdermal Delivery.

The advancement and extensive demand for transdermal therapies can benefit from a safe, and efficient and user-friendly transdermal technology with broad applicability in delivering various hydrophilic drugs. Here the design and proof of concept applications of an ultraswelling microneedle device that enables the facile and efficient loading and transdermal delivery of hydrophilic drugs with different molecular weights is reported. The device consists of a super-hydrophilic hydrogel microneedle array and a resin base substrate. Using a special micromolding technique that involves hydrated crosslinking and cryogenic-demolding, the microneedle part displays a rapid swelling ratio of ≈3800%, enabling the loading of drugs up to 500 kDa in molecular weight. The drug loading process using the device just involves incubating the microneedle part in a drug solution for 1 min, followed by 15 min of drying. The microneedles can easily penetrate the skin under press and detach from the base substrate under shear, thereby releasing the payload. Administration of desired therapeutic agents using the device outperformed conventional administration methods in mitigating psoriasis and eliciting immunity. This biocompatible device, capable of withstanding ethylene oxide sterilization, can enhance the efficacy and accessibility of transdermal therapies in research institutes, hospitals, and even home settings.

An Aptamer-Based Nanoflow Cytometry Method for the Molecular Detection and Classification of Ovarian Cancers through Profiling of Tumor Markers on Small Extracellular Vesicles.

Molecular profiling of protein markers on small extracellular vesicles (sEVs) is a promising strategy for the precise detection and classification of ovarian cancers. However, this strategy is challenging owing to the lack of simple and practical detection methods. In this work, using an aptamer-based nanoflow cytometry (nFCM) detection strategy, a simple and rapid method for the molecular profiling of multiple protein markers on sEVs was developed. The protein markers can be easily labeled with aptamer probes and then rapidly profiled by nFCM. Seven cancer-associated protein markers, including CA125, STIP1, CD24, EpCAM, EGFR, MUC1, and HER2, on plasma sEVs were profiled for the molecular detection and classification of ovarian cancers. Profiling these seven protein markers enabled the precise detection of ovarian cancer with a high accuracy of 94.2 %. In addition, combined with machine learning algorithms, such as linear discriminant analysis (LDA) and random forest (RF), the molecular classifications of ovarian cancer cell lines and subtypes were achieved with overall accuracies of 82.9 % and 55.4 %, respectively. Therefore, this simple, rapid, and non-invasive method exhibited considerable potential for the auxiliary diagnosis and molecular classification of ovarian cancers in clinical practice.

Ratiometric fluorescence determination of alkaline phosphatase activity based on carbon dots and Ce3+-crosslinked copper nanoclusters.

A new ratiometric fluorescent probe for efficient determination of ALP was developed. The probe was constructed by combining Ce3+-crosslinked copper nanoclusters (Ce3+-CuNCs) which exhibit the aggregation-induced emission (AIE) feature with carbon dots (CDs). The introduction of phosphate (Pi) induced the generation of CePO4 precipitation, resulting in significant decrease of fluorescence emission of CuNCs at 634 nm. At the same time, the fluorescence of CDs at 455 nm was obviously enhanced, thus generating ratiometric fluorescence response. Based on the fact that the hydrolysis of pyrophosphate (PPi) by ALP can produce Pi, the CD/Ce3+-CuNCs ratiometric probe was successfully used to determine ALP. A good linear relationship between the ratiometric value of F455/F634 and ALP concentrations ranging from 0.2 to 80 U·L- 1 was obtained, with a low detection limit of 0.1 U·L- 1. The ratiometric responses of the probe resulted in the visible fluorescence color change from orange red to blue with the increase of ALP concentration. The smartphone-based RGB recognition of the fluorescent sample images was used for ALP quantitative determination. A novel ratiometric fluorescent system based on Ce3+-CuNCs with AIE feature and CDs were constructed for efficient detection of ALP.

Responsive calcium-derived nanoassemblies induce mitochondrial disorder to promote tumor calcification.

Physiological calcification of the treated tumor area is considered to be a predictor of good prognosis. Promoting tumor calcification by inducing mitochondrial metabolic disorder and destroying calcium equilibrium has a potential inhibitory effect on tumor proliferation. Here, by promoting calcification by inducing mitochondrial dysfunction combined with triggering a surge of reactive oxygen species, we construct a bioresponsive calcification initiator, termed CaP-AA, using CaHPO4 covalently doped l-ascorbic acid. CaHPO4 releases Ca2+ within the cytoplasm of tumor cells to trigger calcium overload. Meanwhile, exogenous l-ascorbic acid indirectly enhances metabolic balance disruption via pro-oxidant effects. Such Ca2+ overload increases the likelihood of tumor calcification in vivo for tumor inhibition by perturbing mitochondrial homeostasis. The introduction of responsive calcium sources that would, in turn, trigger intratumoral calcification mediated by perturbing mitochondrial homeostasis would be an effective regulatory strategy for tumor therapy.

A Rapidly Dissolvable Microneedle Patch with Tip-Accumulated Antigens for Efficient Transdermal Vaccination.

Dissolvable microneedles (DMNs) are an attractive alternative for vaccine delivery due to their user-friendly, skin-targeted, and minimally invasive features. However, vaccine waste and inaccurate dosage remain significant issues faced by DMNs, as the skin's elasticity makes it difficult to insert MNs completely. Here, a simple and reliable fabrication method are introduced based on two-casting micromolding with centrifugal drying to create a rapidly DMN patch made of hyaluronic acid. Ovalbumin (OVA), as the model antigens, is concentrated in the tip parts of the DMNs (60% of the needle height) to prevent antigen waste caused by skin elasticity. The time and temperature of the initial centrifugal drying significantly affect antigen distribution within the needle tips, with lower temperature facilitating antigen accumulation. The resulting DMN patch is able to penetrate the skin with enough mechanical strength and quickly release antigens into the skin tissue within 3 min. The in vivo study demonstrates that immunization of OVA with DMNs outperforms conventional vaccination routes, including subcutaneous and intramuscular injections, in eliciting both humoral and cellular immunity. This biocompatible DMN patch offers a promising and effective strategy for efficient and safe vaccination.

A Cu2+ triggered reversible photochromic system: the structure photochromic response relationship study and potential applications.

Fifteen rhodamine B hydrazide hydrazone (RhBHH) derivatives (compounds a-o) with various substituent groups at different position and their photochromic property triggered by Cu2+ were studied to illustrate the structure photochromic response relationship (SPRR). Three of them (compounds f-h) with a para-position hydroxyl group and two meta-position halogen substituents display Cu2+-triggered photochromic which is significantly different from the previous reports. It was found that halogen atoms, which were generally considered to have no remarkable regulation effect, exhibited great influences on the photochromic behaviour of RhBHH derivatives. Detail photochromic properties of the developed photochromic system were revealed by using compound g as the model substrate, and only Cu2+ displayed high selective trigger effect. Good reversible photochromic phenomenon was observed after stimulated with visible light irradiation and dark (or heat) bleaching consecutively. Furthermore, this photochromic system could be used in the preparation of photochromic glass, special security ink, molecular logic gate and two-dimensional code for security information storage.

Promoting sensitive colorimetric detection of hydroquinone and Hg2+ via ZIF-8 dispersion enhanced oxidase-mimicking activity of MnO2 nanozyme.

Reducing the agglomeration and improving the dispersibility in water of two-dimensional (2D) nanozymes is one of the effective ways to improve their enzyme-like activity. In this work, we propose a method by constructing zeolitic imidazolate framework-8 (ZIF-8)-dispersed 2D manganese-based nanozymes to achieve the specific regulated improvement of oxidase-mimicking activity. By in-situ growth of manganese oxides nanosheets of MnO2(1), MnO2(2) and Mn3O4 on the surface of ZIF-8, the corresponding nanocomposites of ZIF-8 @MnO2(1), ZIF-8 @MnO2(2), and ZIF-8 @Mn3O4 were prepared at room temperature. The Michaelis-Menton constant measurements indicated that ZIF-8 @MnO2(1) exhibits best substrate affinity and fastest reaction rate for 3,3',5,5'-tetramethylbenzidine (TMB). The ZIF-8 @MnO2(1)-TMB system was exploited to detection of trace hydroquinone (HQ) based on the reducibility of phenolic hydroxyl groups. In addition, by employing the fact that the cysteine (Cys) with the excellent antioxidant capacity can bind the Hg2+ based on the formation of "S-Hg2+" bonds, the ZIF-8 @MnO2(1)-TMB-Cys system was applied to detection of Hg2+ with high sensitivity and selectivity. Our findings not only provide a better understanding of the relationship between dispersion of nanozyme and enzyme-like activity, but also provide a general method for the detection of environmental pollutants using nanozymes.