Spatial Order of Functional Modules Enabling Diverse Intracellular Performance of Fluorescent Probes

Spatiotemporally Controllable Covalent Bonding of RNA for Multi-Protein Interference

Many diseases are associated with genetic mutation and expression of mutated proteins, such as cancers. Therapeutic approaches that selectively target the synthesis process of multiple proteins show greater potential compared to single-protein approaches in oncological diseases. However, conventional agents to regulate the synthesis of multiple protein still suffer from poor spatiotemporal selectivity and stability. Here, a new method using a dye-peptide conjugate, PRFK, for multi-protein interference with spatiotemporal selectivity and reliable stability, is reported. By using the peptide sequence that targets tumor cells, PRFK can be efficiently taken up, followed by specific binding to the KDELR (KDEL receptor) protein located in the endoplasmic reticulum (ER). The dye generates 1O2 under light irradiation, enabling photodynamic therapy. This process converts the furan group into a cytidine-reactive intermediate, which covalently binds to mRNA, thereby blocking protein synthesis. Upon treating 4T1 cells, the proteomics data show alterations in apoptosis, ferroptosis, proliferation, migration, invasion, and immune infiltration, suggesting that multi-protein interference leads to the disruption of cellular physiological activities, ultimately achieving tumor treatment. This study presents a multi-protein interference probe with the potential for protein interference within various subcellular organelles in the future.

A spermine-responsive supramolecular chemotherapy system constructed from a water-soluble pillar[5]arene and a diphenylanthracene-containing amphiphile for precise chemotherapy

Stimuli-responsive supramolecular chemotherapy, particularly in response to cancer biomarkers, has emerged as a promising strategy to overcome the limitations associated with traditional chemotherapy. Spermine (SPM) is known to be overexpressed in certain cancers. In this study, we introduced a novel supramolecular chemotherapy system triggered by SPM. The system featured pyridine salts of a diphenylanthracene derivative (PyEn) and a complementary water-soluble pillar[5]arene (WP5C5) with long alkyl chains. The diphenylanthracene unit of PyEn is effectively encapsulated within the long alkyl chains of WP5C5, resulting in a substantial reduction in the cytotoxicity of PyEn towards normal cells. The therapeutic effect of PyEn is selectively triggered intracellularly through SPM, leading to the endosomal release of PyEn and concurrent in situ cytotoxicity. This supramolecular chemotherapy system exhibits notable tumor inhibition against SPM-overexpressed cancers with reduced side effects on normal tissues. The supramolecular strategy for intracellular activation provides a novel tool with potential applications in chemotherapeutic interventions, offering enhanced selectivity and reduced cytotoxicity to normal cells.

Detection of Unfolded Cellular Proteins Using Nanochannel Arrays with Probe-Functionalized Outer Surfaces

Nanochannel technology has emerged as a powerful tool for label-free and highly sensitive detection of protein folding/unfolding status. However, utilizing the inner walls of a nanochannel array may cause multiple events even for proteins with the same conformation, posing challenges for accurate identification. Herein, we present a platform to detect unfolded proteins through electrical and optical signals using nanochannel arrays with outer-surface probes. The detection principle relies on the specific binding between the maleimide groups in outer-surface probes and the protein cysteine thiols that induce changes in the ionic current and fluorescence intensity responses of the nanochannel array. By taking advantage of this mechanism, the platform has the ability to differentiate folded and unfolded state of proteins based on the exposure of a single cysteine thiol group. The integration of these two signals enhances the reliability and sensitivity of the identification of unfolded protein states and enables the distinction between normal cells and Huntington's disease mutant cells. This study provides an effective approach for the precise analysis of proteins with distinct conformations and holds promise for facilitating the diagnoses of protein conformation-related diseases.

A Peptide-Conjugated Probe with Cleavage-Induced Morphological Change for Treatment on Tumor Cell Membrane

Despite the promising advancements of in situ forming nanoassembly for the inhibition of tumor growth and metastasis, the lack of sufficient triggering sites and hardly controlling the forming position restrict their further developments. Herein, a smart transformable peptide-conjugated probe (DMFA) with enzyme cleavage-induced morphological change is designed for treatment on the tumor cell membrane. Specifically, after self-assembling into nanoparticles and anchoring on the cell membrane with sufficient interaction sites rapidly and stably, DMFA will be efficiently cleaved into α-helix forming part (DP) and β-sheet forming part (LFA) by overexpressed matrix metalloproteinase-2. Thus, the promoted Ca2+ influx by DP-induced cell membrane breakage and decreased Na+ /K+ -ATPase activity by LFA-assembled nanofibers wrapping the cells can inhibit PI3K-Akt signaling pathway, leading to the inhibition of tumor cell growth and metastasis. This peptide-conjugated probe undergoes in situ morphological transformation on the cell membrane, exhibiting great potential in tumor therapy.

Platelet membrane camouflaged AIEgen-mediated photodynamic therapy improves the effectiveness of anti-PD-L1 immunotherapy in large-burden tumors

Although immunotherapy has achieved recent clinical success in antitumor therapy, it is less effective for solid tumors with large burdens. To overcome this challenge, herein, we report a new strategy based on platelet membrane-camouflaged aggregation-induced emission (AIE) luminogen (Plt-M@P) combined with the anti-programmed death ligand 1 (anti-PD-L1) for tumoral photodynamic-immunotherapy. Plt-M@P is prepared by using poly lactic-co-glycolic acid (PLGA)/PF3-PPh3 complex as a nanocore, and then by co-extrusion with platelet membranes. PF3-PPh3 is an AIE-active conjugated polyelectrolyte with photosensitizing capability for photodynamic therapy (PDT). Plt-M@P exhibits superior tumor targeting capacity in vivo. When applied in small tumor-bearing (~40 mm3) mice, Plt-M@P-mediated PDT significantly inhibits tumor growth. In tumor models with large burdens (~200 mm3), using Plt-M@P-mediated PDT or anti-PD-L1 alone is less effective, but the combination of both is effective in inhibiting tumor growth. Importantly, this combination therapy has good biocompatibility, as demonstrated by the absence of damage to the major organs, especially the reproductive system. In conclusion, we show that Plt-M@P-mediated PDT can improve anti-PD-L1 immunotherapy by enhancing antitumor effects, providing a promising strategy for the treatment of tumors with large burdens.

Modular Peptide Probe for Protein Analysis

The analysis and regulation of proteins are of great significance for the development of disease diagnosis and treatment. However, complicated analytical environment and complex protein structure severely limit the accuracy of their analysis results. Nowadays, ascribing to the editability and bioactivity of peptides, peptide-based probes could meet the requirements of good selectivity and high affinity to overcome the challenges. In this review, we summarize the advances in the use of modular peptide probes for proteins analysis. It focuses on how to design and optimize the structure of probes, as well as their performance. Then, the strategies and application to improve the analysis result of modular peptide probes are introduced. Finally, we also discuss current challenge and provide some ideas for the future direction for modular peptide probes, hoping to accelerate their clinical transformation.

Regulating the Membrane Affinity of Multi-module Probes to Address the Trade-off between Anchoring and Internalization

Cell membrane transport is the first and crucial step for bioprobes to realize the diagnosis, imaging, and therapy in cells. However, during this transport, there is a trade-off between anchoring and internalization steps, which will seriously affect the membrane transport efficiency. In the past, because the interaction between probes and cell membrane is constant, this challenge is hard to solve. Here, we proposed a strategy to regulate the membrane affinity of multi-module probes that enabled probe to have strong affinity during cell membrane anchoring and weak affinity during internalization. Specifically, a multi-module probe defined as LK-M-NA was constructed, which consisted of three main parts, membrane-anchoring α-helix peptide (LK), anchoring regulator (M), and therapeutic module (NA). With the α-helix module, LK-M-NA was able to rapidly anchor on the cell membrane and the binding energy was -1450.90 kcal/mol. However, after pericellular cleavage by the highly active matrix metalloproteinase-2 , LK could be removed due to the breakage of M and the binding energy reduced to -869.95 kcal/mol. Thus, the internalization restriction caused by high affinity was relieved. Owing to the alterable affinity, the membrane transport efficiency of LK-M-NA increased to 14.58%, well addressing the trade-off problem.

Aggregation-Induced Emission Luminogens for Enhanced Photodynamic Therapy: From Organelle Targeting to Tumor Targeting

Photodynamic therapy (PDT) has attracted much attention in the field of anticancer treatment. However, PDT has to face challenges, such as aggregation caused by quenching of reactive oxygen species (ROS), and short 1O2 lifetime, which lead to unsatisfactory therapeutic effect. Aggregation-induced emission luminogen (AIEgens)-based photosensitizers (PSs) showed enhanced ROS generation upon aggregation, which showed great potential for hypoxic tumor treatment with enhanced PDT effect. In this review, we summarized the design strategies and applications of AIEgen-based PSs with improved PDT efficacy since 2019. Firstly, we introduce the research background and some basic knowledge in the related field. Secondly, the recent approaches of AIEgen-based PSs for enhanced PDT are summarized in two categories: (1) organelle-targeting PSs that could cause direct damage to organelles to enhance PDT effects, and (2) PSs with tumor-targeting abilities to selectively suppress tumor growth and reduce side effects. Finally, current challenges and future opportunities are discussed. We hope this review can offer new insights and inspirations for the development of AIEgen-based PSs for better PDT effect.

Activating Innate Immunity by a STING Signal Amplifier for Local and Systemic Immunotherapy

The number of patients who benefit from acquired immunotherapy is limited. Stimulator of interferon genes (STING) signal activation is a significant component to enhance innate immunity, which has been used to realize broad-spectrum immunotherapy. Here, M@P@HA nanoparticles, as a STING signal amplifier, are constructed to enhance innate immunotherapy. Briefly, when M@P@HA was targeted into tumor cells, the nanoparticles decomposed with Mn²⁺ and activated the release of protoporphyrin (PpIX). Under light irradiation, the generated reactive oxygen species disrupt the cellular redox homeostasis to lead cytoplasm leakage of damaged mitochondrial double-stranded (ds) DNA, which is the initiator of the STING signal. Simultaneously, Mn²⁺ as the immunoregulator could significantly increase the activity of related protein of a STING signal, such as cyclic GMP-AMP synthase (cGAS) and STING, to further amplify the STING signal of tumor cells. Subsequently, the STING signal of tumor-associated macrophages (TAM) is also activated by capturing dsDNA and Mn²⁺ that escaped from tumor cells, so as to enhance innate immunity. It is found that, by amplifying the STING signal of tumor tissue, M@P@HA could not only activate innate immunity but also cascade to activate CD8⁺ T cell infiltration even in a tumor with low immunogenicity.

AIEgen-Peptide Bioprobes for the Imaging of Organelles

Organelles are important subsystems of cells. The damage and inactivation of organelles are closely related to the occurrence of diseases. Organelles’ functional activity can be observed by fluorescence molecular tools. Nowadays, a series of aggregation-induced emission (AIE) bioprobes with organelles-targeting ability have emerged, showing great potential in visualizing the interactions between probes and different organelles. Among them, AIE luminogen (AIEgen)-based peptide bioprobes have attracted more and more attention from researchers due to their good biocompatibility and photostability and abundant diversity. In this review, we summarize the progress of AIEgen-peptide bioprobes in targeting organelles, including the cell membrane, nucleus, mitochondria, lysosomes and endoplasmic reticulum, in recent years. The structural characteristics and biological applications of these bioprobes are discussed, and the development prospect of this field is forecasted. It is hoped that this review will provide guidance for the development of AIEgen-peptide bioprobes at the organelles level and provide a reference for related biomedical research.

Programmable design and self assembly of peptide conjugated AIEgens for biomedical applications

Aggregation-induced emission luminogens (AIEgens) possess enhanced fluorescence in highly aggregated states, thus enabling AIEgens as a promising module for highly emissive fluorescence biomaterials. So far, AIEgens-based nanomaterials and their hybrids have been reported for biomedical applications. Benefiting from the intrinsic biocompatibility and biofunction-editing properties of peptides, peptide-AIEgens hybrid biomaterials reveal unlimited possibilities including target capacity, specificity, stimuli-responsiveness, self-assembly, controllable structural transformation, etc.. In the last two decades, peptide-AIEgens hybrid nanomaterials with a unique design concept in aggregated states have achieved various biomedical applications such as biosensing, bioimaging, imaging-guided surgery, drug delivery and therapy. More recently, programmable design of peptide-AIEgens for in situ self-assembly provides a unique strategy for constructing intelligent entities with defined biological functions. In this review, we summarize the basic design principle of programmable peptide-AIEgens, structure-effect relationship and their unusual biomedical effects. Finally, an outlook and perspective toward future challenges and developments of peptide-AIEgens nanomaterials are concluded.

Endocytosis Pathway Self-Regulation for Precise Image-Guided Therapy through an Enzyme-Responsive Modular Peptide Probe

Before arriving at the intracellular destinations, probes might be trapped in the lysosomes, reducing the amount of cargos, which compromises the therapeutic outcomes. The current methods are based on the fact that probes enter the lysosomes and then escape from them, which do not fundamentally solve the degradation by lysosomal hydrolases. Here, an enzyme-responsive modular peptide probe named PKP that can be divided into two parts, Pal-part and KP-part, by matrix metalloproteinase-2 (MMP-2) overexpressed in tumor microenvironments is designed. Pal-part quickly enters the cells and forms nanofibers in the lysosomes, decreasing protein phosphatase 2A (PP2A), which transforms the endocytic pathway of KP-part from clathrin-mediated endocytosis (CME) into caveolae-mediated endocytosis (CvME) and allows KP-part to directly reach the mitochondria sites without passing through the lysosomes. Finally, through self-regulating intracellular delivery pathways, the mitochondrial delivery efficiency of KP-part is greatly improved, leading to an optimized image-guided therapeutic efficiency. Furthermore, this system also shows great potential for the delivery of siRNA and doxorubicin to achieve precise cancer image-guided therapy, which is expected to significantly expand its application and facilitate the development of personalized therapy.

Insight into the spatial interaction of D-π-A bridge derived cyanines and nitroreductase for fluorescent cancer hypoxia detection

Nitroreductase (NTR) detection in tumor is critical because NTR level is correlated with hypoxia degree and cancer prognosis. With the feature of high sensitivity and selectivity, fluorescence organic probes for NTR detection exhibited a promising future for tumor hypoxia detection. However, the discovery and design of such probes have been impeded due to the lack of the understanding of spatial match and mismatch of these probes with NTR. Here, we have developed two new nitrophenyl-functionalized trimethincyanine (Cy3) probes with para- or meta- positions of nitro-group in phenyl ring. Para-nitrophenyl substituted Cy3 (pNP-Cy3) exhibited a remarkable response to NTR (20-fold fluorescence enhancement) with good selectivity and sensitivity. Experimental and theoretical analysis verified that the substituent position of nitro group on phenyl ring of dyes altered the spatial arrangement of nitro-substituent group, thereby modulated the spatial match and mismatch between Cy3 dyes and binding domain of NTR, and consequently led to a different fluorescent turn-on response. In tumor-bearing mice model, hypoxia status of A549 xenografted tumor of mice was successfully delineated by using pNP-Cy3. These results may provide a clue for designing new cyanine-derived NTR probe to monitor NTR-overexpressed hypoxia cancer cells.

Deep Downregulation of PD-L1 by Caged Peptide-Conjugated AIEgen/miR-140 Nanoparticles for Enhanced Immunotherapy

Downregulating programmed cell death ligand 1(PD-L1) protein levels in tumor cells is an effective way to achieve immune system activation for oncology treatment, but current strategies are inadequate. Here, we design a caged peptide-AIEgen probe (GCP) to self-assemble with miR-140 forming GCP/miR-140 nanoparticles. After entering tumor cells, GCP/miR-140 disassembles in the presence of Cathepsin B (CB) and releases caged GO203 peptide, miR-140 and PyTPA. Peptide decages in the highly reductive intracellular environment and binds to mucin 1 (MUC1), thereby downregulating the expression of PD-L1. Meanwhile, miR-140 reduces PD-L1 expression by targeting downregulation of PD-L1 mRNA. Under the action of PyTPA-mediated photodynamic therapy (PDT), tumor-associated antigens are released, triggering immune cell attack on tumor cells. This multiple mechanism-based strategy of deeply downregulating PD-L1 in tumor cells activates the immune system and thus achieves effective immunotherapy.

Precisely Detecting the Telomerase Activities by an AIEgen Probe with Dual Signal Outputs after Cell-Cycle Synchronization

By maintaining the telomere lengths, telomerase can make the tumor cells avoid the apoptosis, thus, achieving the cell immortalization. In the past, a series of telomerase detection systems have been developed through utilizing the unique characteristic of telomerase extended primer. However, fluctuation of telomerase activity, along with the cell cycle progression, leads to ambiguous detection results. Here, we reported a dual signal output detection strategy based on cell-cycle synchronization for precisely detecting telomerase activities by using a new AIEgen probe SSNB. Experimental and simulating calculation results demonstrated that positively charged SSNB could interact with DNA through the electrostatic interaction and π-π interaction, as well as the hydrogen bonds. The aggregation of SSNB caused by the extended template strand primer (TP) could be observed in tumor cells, thus, indicating the telomerase activity in various cell lines. Furthermore, after cell cycle synchronization, it was found that the telomerase activity in the S phase was the highest, no matter from the fluorescence intensity or the ROS generation situation. Dual signal outputs of SSNB verified the significance and necessity of cell-cycle synchronization detection for telomerase activity. This strategy could open a new window for the biotargets of which activity is variational in time dimension.

The fast-growing field of photo-driven theranostics based on aggregation-induced emission

Photo-driven theranostics, also known as phototheranostics, relying on the diverse excited-state energy conversions of theranostic agents upon photoexcitation represents a significant branch of theranostics, which ingeniously integrate diagnostic imaging and therapeutic interventions into a single formulation. The combined merits of photoexcitation and theranostics endow photo-driven theranostics with numerous superior features. The applications of aggregation-induced emission luminogens (AIEgens), a particular category of fluorophores, in the field of photo-driven theranostics have been intensively studied by virtue of their versatile advantageous merits of favorable biocompatibility, tuneable photophysical properties, unique aggregation-enhanced theranostic (AET) features, ideal AET-favored on-site activation ability and ready construction of one-for-all multimodal theranostics. This review summarised the significant achievements of photo-driven theranostics based on AIEgens, which were detailedly elaborated and classified by their diverse theranostic modalities into three groups: fluorescence imaging-guided photodynamic therapy, photoacoustic imaging-guided photothermal therapy, and multi-modality theranostics. Particularly, the tremendous advantages and individual design strategies of AIEgens in pursuit of high-performance photosensitizing output, high photothermal conversion and multimodal function capability by adjusting the excited-state energy dissipation pathways are emphasized in each section. In addition to highlighting AIEgens as promising templates for modulating energy dissipation in the application of photo-driven theranostics, current challenges and opportunities in this field are also discussed.

Molecular dynamics simulation-guided toehold mediated strand displacement probe for single-nucleotide variants detection

Single nucleotide variant (SNV) has become an emerging biomarker for various diseases such as cancers and infectious diseases. Toehold-mediated strand displacement (TMSD), the core reaction of DNA nanotechnology, has been widely leveraged to identify SNVs. However, inappropriate choice of mismatch location results in poor discrimination ability. Here, we comprehensively investigate the effect of mismatch location on TMSD kinetics by molecular dynamic simulation tool oxDNA through umbrella sampling and forward flux sampling disclosing that mismatches at the border of the toehold and branch migration domain yield the lowest TMSD reaction rate. Nine disease-related SNVs (SARS-CoV-2-D614G, EGFR-L858R, EGFR-T790M, KRAS-G12R, etc.) were tested experimentally showing a good agreement with simulation. The best choice of mismatch location enables high discrimination factor with a median of 124 for SNV and wild type. Coupling with a probe-sink system, a low variant allele frequency of 0.1% was detected with 3 S/N. We successfully used the probes to detect SNVs with high confidence in the PCR clones of constructed plasmids. This work provides mechanistic insights into TMSD process at the single-nucleotide level and can be a guidance for the design of TMSD system with fine-tuning kinetics for various applications in biosensors and nanotechnology.

High-Performance Near-Infrared Aggregation-Induced Emission Luminogen with Mitophagy Regulating Capability for Multimodal Cancer Theranostics

The construction of intelligent near-infrared (NIR) fluorophores for high specificity to cancer cells and application in multiple therapeutic modalities is crucial for precise cancer diagnostic and therapy. In this study, an aggregation-induced emission-active NIR fluorophore (TACQ) with mitophagy-modulating activity was synthesized and developed for mitochondrial targeting multimodal cancer theranostics. The strengthened push-pull interaction extended the emission of TACQ into the NIR-II region (>1000 nm). Further, the rotor structure and twisted molecular conformation enables nanoaggregates of TACQ to balance the radiative and nonradiative decays to simultaneously exhibit bright NIR emission, high photothermal conversion efficiency (55%), and efficient generation of reactive oxygen species. The lipocationic property of TACQ allows it to selectively accumulate in the mitochondria of cancer cells. TACQ can induce mitophagy and block mitophagic flux facilitating cancer cell apoptosis. Both in vitro and in vivo evaluations revealed that TACQ is an efficient theranostic agent for NIR fluorescence and photothermal imaging-guided synergistic chemo-photothermal and photodynamic therapy.

Tunning Intermolecular Interaction of Peptide-Conjugated AIEgen in Nano-Confined Space for Quantitative Detection of Tumor Marker Secreted from Cells

Determining the expression level of biomarkers is crucial for disease diagnosis. However, the low abundance of biomarkers in the early stage makes the detection extremely difficult by traditional aggregation-induced emission (AIE)-based fluorescent probes. Here, by tuning the intermolecular interaction, a two steps-based MP/NPs-SLIPS sensing system is designed for ultrasensitive detection of the tumor marker matrix metalloproteinase-2 (MMP-2). During the sensing process, aggregation of AIE residual could be intensified through the electrostatic absorption by negatively charged nanoparticles (NPs), as well as the confined space formed by the self-assembly of NPs to photonic crystals (PCs) on slippery lubricant-infused porous substrates (SLIPS). The fluorescent signals obviously increased with a strengthened aggregation degree, which contributes to improved sensitivity. Thus, the limit of detection is decreased to 3.7 ng/mL for MP/NPs-SLIPS sensing system, which could be used for detecting the MMP-2 secreted by tumor cells directly. This strategy also demonstrated its potential applications as high-throughput detection devices and will be of significance for the ultrasensitive analysis of biomarkers.

Cationization to boost both type I and type II ROS generation for photodynamic therapy

The pursuing of photosensitizers (PSs) with efficient reactive oxygen species (ROS) especially type I ROS generation in aggregate is always in high demand for photodynamic therapy (PDT) and photoimmunotherapy but remains to be a big challenge. Herein, we report a cationization molecular engineering strategy to boost both singlet oxygen and radical generation for PDT. Cationization could convert the neutral donor-acceptor (D-A) typed molecules with the dicyanoisophorone-triphenylamine core (DTPAN, DTPAPy) to their A-D-A' typed cationic counterparts (DTPANPF₆ and DTPAPyPF₆). Our experiment and simulation results reveal that such cationization could enhance the aggregation-induced emission (AIE) feature, promote the intersystem crossing (ISC) processes, and increase the charge transfer and separation ability, all of which work collaboratively to promote the efficient generation of ROS especially hydroxyl and superoxide radicals in aggregates. Moreover, these cationic AIE PSs also possess specific cancer cell mitochondrial targeting capability, which could further promote the PDT efficacy both in vitro and in vivo. Therefore, we expect this delicate molecular design represents an attractive paradigm to guide the design of type I AIE PSs for the further development of PDT.

AIEgen-Based Lifetime-Probes for Precise Furin Quantification and Identification of Cell Subtypes

Biochemical sensing probes based on aggregation-induced-emission luminogens (AIEgens) are widely used in biological imaging and therapy, chemical sensing, and material sciences. However, it is still a great challenge to quantify the targets through fluorescence intensity of AIEgen probes due to their undesirable aggregations. Here, a PyTPA-ZGO probe with three lifetime signals for precise quantification of furin is constructed: the lifetime signal 1 and signal 2 comes from AIEgen PyTPA-P (τ_Pn ) and inorganic nanoparticles Zn₂ GeO₄ :Mn²⁺ -NH₂ (τ_Zn ), respectively, while the lifetime signal 3 is marked as the composite dual-lifetime signal (CDLS_n , C D L S n = τ Z n τ P n ). In contrast, the fluorescence intensity signal of PyTPA-P shows defectively quantitative performance. Furthermore, it is found that the CDLS_n exhibits higher significant differences than the two other lifetime signals (τ_Pn and τ_Zn ) thanks to its wide range between the maximum and minimum signal values and small standard deviation. Therefore, CDLS_n is further used to accurately identify cell subtypes based on the specific concentration of furin in each subtype. The lifetime criterion can realize precise quantification, and it should be a promising direction of AIEgen-based quantitative analysis in the future.

Solid-State Nanochannel with Multiple Signal Outputs for Furin Detection Based on the Biocompatible Condensation Reaction

Utilizing ionic current and fluorescent dual-signal-output nanochannels to achieve the detection of specific target species has received much attention. The introduction of an optical signal could not only improve the selectivity of the detection systems, but also make it possible to observe the reduction of the ionic current that originated from stimulus-triggered nanochannel changes. However, the resolution of an optical signal can only verify issues of the presence or absence and cannot precisely analyze the detailed chemical structural changes within nanochannels. Here, we employed a biocompatible condensation reaction between 2-cyanobenzothiazole (CBT) and d-cysteine, and synthesized molecules PCTC that can be polymerized by cutting off short peptide sequences in the presence of furin to realize the detection of furin with multiple signal outputs. Through the introduction of a UV light-sensitive DNA sequence to the capture probes (CPs) inside the nanochannels, the blocking of the nanochannels can be confirmed to the formed oligomers by mass spectrometry analysis.