Emerging Sonodynamic Therapy-Based Nanomedicines for Cancer Immunotherapy

Cancer immunotherapy effect can be greatly enhanced by other methods to induce immunogenic cell death (ICD), which has profoundly affected immunotherapy as a highly efficient paradigm. However, these treatments have significant limitations, either by causing damage of the immune system or limited to superficial tumors. Sonodynamic therapy (SDT) can induce ICD to promote immunotherapy without affecting the immune system because of its excellent spatiotemporal selectivity and low side effects. Nevertheless, SDT is still limited by low reactive oxygen species yield and the complex tumor microenvironment. Recently, some emerging SDT-based nanomedicines have made numerous attractive and encouraging achievements in the field of cancer immunotherapy due to high immunotherapeutic efficiency. However, this cross-cutting field of research is still far from being widely explored due to huge professional barriers. Herein, the characteristics of the tumor immune microenvironment and the mechanisms of ICD are firstly systematically summarized. Subsequently, the therapeutic mechanism of SDT is fully summarized, and the advantages and limitations of SDT are discussed. The representative advances of SDT-based nanomedicines for cancer immunotherapy are further highlighted. Finally, the application prospects and challenges of SDT-based immunotherapy in future clinical translation are discussed.

Atomic Dispersion of Zn2+ on N-Doped Carbon Materials: From Non-Activity to High Activity for Catalyzing Luminol-H2O2 Chemiluminescence

Fe and Co single-atom catalysts (SACs) have been widely explored in many fields, while Zn SACs are still in their infancy stage. Herein, we unexpectedly found that atomically dispersed Zn²⁺ on N-doped carbon material (Zn-N-C) exhibited high catalytic activity on luminol-H₂O₂ chemiluminescence (CL) reaction. The Zn-N-C SACs were readily prepared through simple pyrolyzation of the cheap precursors (dopamine and ZnCl₂). The mechanism of Zn SAC-catalyzed CL reaction of luminol-H₂O₂ was investigated in detail. The activity of Zn SACs originated from the Zn-N sites in the Zn-N-C structure. The monoatomic dispersion makes Zn²⁺ catalytic performance change from no activity to high activity in luminol-H₂O₂ CL reaction. This study demonstrated the particularity of the monatomic metal catalyst over the conventional metal ion. This work provides the unprecedented perspective for design of new metal SACs in CL reaction.

Dioxetane Derivative Containing Carboxy Group as a Chemiluminophore-Introducing Reagent

Some types of dioxetanes are called chemiluminophores because they produce luminescence light without the use of enzymes. Here, we designed and synthesized a novel carboxy group-containing chemiluminophore derivative, which enabled the simple introduction of such a chemiluminophore to the molecule of interest. Furthermore, we demonstrate that the in vivo imaging system (IVIS imaging system) can recognize tagged chemicals, indicating that such a chemiluminophore could be employed as a tracer molecule for biological studies.

Combined Experimental and Theoretical Investigation into the Photophysical Properties of Halogenated Coelenteramide Analogs

Marine Coelenterazine is one of the most well-known chemi-/bioluminescent systems, and in which reaction the chemi-/bioluminophore (Coelenteramide) is generated and chemiexcited to singlet excited states (leading to light emission). Recent studies have shown that the bromination of compounds associated with the marine Coelenterazine system can provide them with new properties, such as anticancer activity and enhanced emission. Given this, our objective is to characterize the photophysical properties of a previously reported brominated Coelenteramide analog, by employing a combined experimental and theoretical approach. To better analyze the potential halogen effect, we have also synthesized and characterized, for the first time, two new fluorinated and chlorinated Coelenteramide analogs. These compounds show similar emission spectra in aqueous solution, but with different fluorescence quantum yields, in a trend that can be correlated with the heavy-atom effect (F > Cl > Br). A blue shift in emission in other solvents is also verified with the F−Cl−Br trend. More relevantly, the fluorescence quantum yield of the brominated analog is particularly sensitive to changes in solvent, which indicates that this compound has potential use as a microenvironment fluorescence probe. Theoretical calculations indicate that the observed excited state transitions result from local excitations involving the pyrazine ring. The obtained information should be useful for the further exploration of halogenated Coelenteramides and their luminescent properties.

Wireless electrochemical light emission in ultrathin 2D nanoconfinements

Spatial confinement of chemical reactions or physical effects may lead to original phenomena and new properties. Here, the generation of electrochemiluminescence (ECL) in confined free-standing 2D spaces, exemplified by surfactant-based air bubbles is reported. For this, the ultrathin walls of the bubbles (typically in the range of 100-700 nm) are chosen as a host where graphene sheets, acting as bipolar ECL-emitting electrodes, are trapped and dispersed. The proposed system demonstrates that the required potential for the generation of ECL is up to three orders of magnitude smaller compared to conventional systems, due to the nanoconfinement of the potential drop. This proof-of-concept study demonstrates the key advantages of a 2D environment, allowing a wireless activation of ECL at rather low potentials, compatible with (bio)analytical systems.

Organic persistent luminescence imaging for biomedical applications

Persistent luminescence is a unique visual phenomenon that occurs after cessation of excitation light irradiation or following oxidization of luminescent molecules. The energy stored within the molecule is released in a delayed manner, resulting in luminescence that can be maintained for seconds, minutes, hours, or even days. Organic persistent luminescence materials (OPLMs) are highly robust and their facile modification and assembly into biocompatible nanostructures makes them attractive tools for in vivo bioimaging, whilst offering an alternative to conventional fluorescence imaging materials for biomedical applications. In this review, we give attention to the existing limitations of each class of OPLM-based molecular bioimaging probes based on their luminescence mechanisms, and how recent research progress has driven efforts to circumvent their shortcomings. We discuss the multifunctionality-focused design strategies, and the broad biological application prospects of these molecular probes. Furthermore, we provide insights into the next generation of OPLMs being developed for bioimaging techniques.

A chemical timer approach to delayed chemiluminescence

Although the onset time of chemical reactions can be manipulated by mechanical, electrical, and optical methods, its chemical control remains highly challenging. Herein, we report a chemical timer approach for manipulating the emission onset time of chemiluminescence (CL) reactions. A mixture of Mn²⁺, NaHCO₃, and a luminol analog with H₂O₂ produced reactive oxygen species (ROS) radicals and other superoxo species (superoxide containing complex) with high efficiency, accompanied by strong and immediate CL emission. Surprisingly, the addition of thiourea postponed CL emission in a concentration-dependent manner. The delay was attributed to a slow-generation-scavenging mechanism, which was found to be generally applicable not only to various types of CL reagents and ROS radical scavengers but also to popular chromogenic reactions. The precise regulation of CL kinetics was further utilized in dynamic chemical coding with improved coding density and security. This approach provides a powerful platform for engineering chemical reaction kinetics using chemical timers, which is of application potential in bioassays, biosensors, CL microscopic imaging, microchips, array chips, and informatics.

Chemiluminescence in Combination with Organic Photosensitizers: Beyond the Light Penetration Depth Limit of Photodynamic Therapy

Photodynamic therapy (PDT) is a promising noninvasive medical technology that has been approved for the treatment of a variety of diseases, including bacterial and fungal infections, skin diseases, and several types of cancer. In recent decades, many photosensitizers have been developed and applied in PDT. However, PDT is still limited by light penetration depth, although many near-infrared photosensitizers have emerged. The chemiluminescence-mediated PDT (CL-PDT) system has recently received attention because it does not require an external light source to achieve targeted PDT. This review focuses on the rational design of organic CL-PDT systems. Specifically, PDT types, light wavelength, the chemiluminescence concept and principle, and the design of CL-PDT systems are introduced. Furthermore, chemiluminescent fraction examples, strategies for combining chemiluminescence with PDT, and current cellular and animal applications are highlighted. Finally, the current challenges and possible solutions to CL-PDT systems are discussed.

Development of lucigenin-N-hydroxyphthalimide chemiluminescence system and its application to sensitive detection of Co2

N-hydroxyphthalimide (NHPI) is an efficient organic catalyst and an important chemical raw material which can be used as an intermediate in organic synthesis of drugs and pesticides. In this study, NHPI has been used as a coreactant of lucigenin chemiluminescence (CL) for the first time. The CL of the developed system is significantly enhanced in the presence of Co²⁺. Therefore, we developed a novel lucigenin-NHPI CL method coupled with flow injection analysis for the sensitive, precise, and selective determination of Co²⁺. The linear range of this method is 1-1000 nM, and the detection limit is 67 pM (S/N = 3). In addition, this method has a good selectivity for Co²⁺. It has been applied to the detection of Co²⁺ in lake water, and the standard recovery rate is 95.9-103.2%, indicating that the method is feasible.

Can machine learning methods accurately predict the molar absorption coefficient of different classes of dyes?

In this article, we provide a convenient tool for all researchers to predict the value of the molar absorption coefficient for a wide number of dyes without any computer costs. The new model is based on RFR method (ALogPS, OEstate + Fragmentor + QNPR) and is able to predict the molar absorption coefficient with an accuracy (5-fold cross-validation RMSE) of 0.26 log unit. This accuracy was achieved due to the fact that the model was trained on data for more than 20,000 unique dye molecules. To our knowledge, this is the first model for predicting the molar absorption coefficient trained on such a large and diverse set of dyes. The model is available at https://ochem.eu/article/145413. We hope that the new model will allow researchers to predict dyes with practically significant spectral characteristics and verify existing experimental data.

An Activatable Near-Infrared Afterglow Theranostic Prodrug with Self-Sustainable Magnification Effect of Immunogenic Cell Death

Herein, we report an activatable near-infrared (NIR) afterglow theranostic prodrug that circumvents high background noise interference caused by external light excitation. The prodrug can release hydroxycamptothecin (HCPT) in response to the high intratumoral peroxynitrite level associated with immunogenic cell death (ICD), and synchronously activate afterglow signal to monitor the drug release process and cold-to-hot tumor transformation. The prodrug itself is an ICD inducer achieved by photodynamic therapy (PDT). PDT initiates ICD and recruits first-arrived neutrophils to secrete peroxynitrite to trigger HCPT release. Intriguingly, we demonstrate that HCPT can significantly amplify PDT-mediated ICD process. The prodrug thus shows a self-sustainable ICD magnification effect by establishing an "ICD-HCPT release-amplified ICD" cycling loop. In vivo studies demonstrate that the prodrug can eradicate existing tumors and prevent further tumor recurrence through antitumor immune response.

Meter-scale chemiluminescent carbon nanodot films for temperature imaging

Chemiluminescence (CL), as one class of luminescence driven by chemical reaction, exhibits obvious temperature-dependence in its light emission process. Herein, temperature-dependent CL emission of carbon nanodots (CDs) in the chemical reaction of peroxalate and hydrogen peroxide is demonstrated and temperature imaging based on the temperature-dependent CL has been established for the first time. In detail, the temperature-dependent CL emission of CDs in the chemical reaction of peroxalate and hydrogen peroxide is observed, and the linear relationship between the CL intensity and temperature is demonstrated in both the CL solution and film, enabling their applications in temperature sensing and imaging capabilities. The increase of the CL emission with temperature can be attributed to the accelerated electron exchange between the CDs and intermediate generated in the peroxalate system. Meter-scale chemiluminescent CD films have been constructed. The CL sensor based on the films presents a high spatial resolution of 0.4 mm and an outstanding sensitivity of 0.08 °C^-1, which is amongst the best values for the thermographic luminophores. With the unique temperature response and flexible properties, non-planar, meter-scale and sensitive palm temperature imaging has been achieved. These findings present new opportunities for designing CL-based temperature probes and thermography.

Optical sensing techniques for rapid detection of agrochemicals: Strategies, challenges, and perspectives

In recent years, the irrational use of agrochemicals has caused great harm to the environment and public health. Along with the rapid development of optical technology and nanotechnology, the research of optical sensing methods in agrochemical detection has been developed rapidly owing to its advantages of simplicity, fast response, and cost-effectiveness. In this review, the strategies of employing optical systems based on colorimetric sensor, fluorescence, chemiluminescence, terahertz spectroscopy, surface plasmon resonance, and surface-enhanced Raman spectroscopy for sensing agrochemicals were summarized. In addition, the challenges in the practical application of optical sensing technologies for agrochemical detection were discussed in-depth, and potential future trends and prospects of these techniques were addressed. A variety of nanomaterials have been developed for enhancing the sensitivity of optical sensing systems. The optical properties of nanomaterials are governed by their size, shape, and chemical structure. Although each optical sensing system holds its advantages, there are still many challenges that need to be overcome in practical applications. With the continuous developments in novel functional nanomaterials, sample preparation methods, and spectral processing algorithms, optical sensors are expected to have powerful potential for rapid testing of agrochemicals in the environment and foods.

Derivatization-free determination of carbonyl compounds using bifunctional chemiluminescence coreactant thiourea dioxide

Uniquely, thiourea dioxide not only can reduce carbonyl compounds but also generate an oxidant to trigger luminol chemiluminescence. Herein, derivatization-free carbonyl compound detection using bifunctional chemiluminescence coreactant thiourea dioxide has been developed for the first time with the second most crucial flavor benzaldehyde as a representative.

Small-Molecules as Chemiluminescent Probes to Detect Lipase Activity

The set-up of highly sensitive detection tools to evaluate lipase activity remains a central goal in different fields. In this context, we proposed new chemiluminescent 1,2-dioxetane luminophores, sharing an octanoyl triggerable group, to monitor lipase activity. We herein report the synthesis and both the evaluation of their luminescence emission profile and their enzyme-substrate specificity, generated by three different commercial lipases (Candida cylindracea, Pseudomonas fluorescens, and Mucor miehei) and one esterase (porcine liver esterase, PLE, as a literature control). Remarkably, the present study confirmed the applicability of these 1,2-dioxetane luminophores as (i) highly efficient, broad-range, chemiluminescent probes for the detection and the enzymatic activity evaluation of lipases and as (ii) promising candidates for the future development of both flash- and glow-type luminescence assays.

Rational Design of NIR-II AIEgens with Ultrahigh Quantum Yields for Photo- and Chemiluminescence Imaging

Fluorescence imaging in the second near-infrared window (NIR-II, 1000-1700 nm) using small-molecule dyes has high potential for clinical use. However, many NIR-II dyes suffer from the emission quenching effect and extremely low quantum yields (QYs) in the practical usage forms. The AIE strategy has been successfully utilized to develop NIR-II dyes with donor-acceptor (D-A) structures with acceptable QYs in the aggregate state, but there is still large room for QY improvement. Here, we rationally designed a NIR-II emissive dye named TPE-BBT and its derivative (TPEO-BBT) by changing the electron-donating triphenylamine unit to tetraphenylethylene (TPE). Their nanoparticles exhibited ultrahigh relative QYs of 31.5% and 23.9% in water, respectively. By using an integrating sphere, the absolute QY of TPE-BBT nanoparticles was measured to be 1.8% in water. Its crystals showed an absolute QY of 10.4%, which is the highest value among organic small molecules reported so far. The optimized D-A interaction and the higher rigidity of TPE-BBT in the aggregate state are believed to be the two key factors for its ultrahigh QY. Finally, we utilized TPE-BBT for NIR-II photoluminescence (PL) and chemiluminescence (CL) bioimaging through successive CL resonance energy transfer and Förster resonance energy transfer processes. The ultrahigh QY of TPE-BBT realized an excellent PL imaging quality in mouse blood vessels and an excellent CL imaging quality in the local arthrosis inflammation in mice with a high signal-to-background ratio of 130. Thus, the design strategy presented here brings new possibilities for the development of bright NIR-II dyes and NIR-II bioimaging technologies.

Membrane dual-targeting probes: A promising strategy for fluorescence-guided prostate cancer surgery and lymph node metastases detection

Fluorescence-guided surgery (FGS) with tumor-targeted imaging agents, particularly those using the near-infrared wavelength, has emerged as a real-time technique to highlight the tumor location and margins during a surgical procedure. For accurate visualization of prostate cancer (PCa) boundary and lymphatic metastasis, we developed a new approach involving an efficient self-quenched near-infrared fluorescence probe, Cy-KUE-OA, with dual PCa-membrane affinity. Cy-KUE-OA specifically targeted the prostate-specific membrane antigen (PSMA), anchored into the phospholipids of the cell membrane of PCa cells and consequently showed a strong Cy7-de-quenching effect. This dual-membrane-targeting probe allowed us to detect PSMA-expressing PCa cells both in vitro and in vivo and enabled clear visualization of the tumor boundary during fluorescence-guided laparoscopic surgery in PCa mouse models. Furthermore, the high PCa preference of Cy-KUE-OA was confirmed on surgically resected patient specimens of healthy tissues, PCa, and lymph node metastases. Taken together, our results serve as a bridge between preclinical and clinical research in FGS of PCa and lay a solid foundation for further clinical research.

Potassium Ferricyanide Oxidize Silicon Quantum Dots under Alkaline Condition to Produce Chemiluminescence for Uric Acid Detection in Human Urine

Potassium ferricyanide (K₃ [Fe (CN)₆ ]) could directly oxidize silicon quantum dots (Si QDs) to generate chemiluminescence (CL) under alkaline condition. It was noteworthy that in the Si QDs-K₃ [Fe (CN)₆ ]-NaOH CL system, the Si QDs worked as a new luminescent material. Besides, the signal intensity of this CL system could be weaken with the addition of uric acid (UA). Based on these, we exploited a new painless and convenient determination method of UA. This method only needed to filter and dilute the UA, without other pretreatment. The constructed system exhibited a linear relationship ranged from 0.50 to 4.50 mmol·L^-1 , with 0.24 mmol·L^-1 of detection limit, and this system had been successfully demonstrated the detection of UA in human urine. Meanwhile, this work had also broaden the application of the Si QDs in CL research.

Ultrasound triggered organic mechanoluminescence materials

Ultrasound induced organic mechanoluminescence materials have become one of the focal topics in wireless light sources since they exhibit high spatiotemporal resolution, biocompatibility and excellent tissue penetration depth. These properties promote great potential in ultrahigh sensitive bioimaging with no background noise and noninvasive nanodevices. Recent advances in chemistry, nanotechnology and biomedical research are revolutionizing ultrasound induced organic mechanoluminescence. Herein, we try to summarize some recent researches in ultrasound induced mechanoluminescence that use various materials design strategies based on the molecular conformational changes and cycloreversion reaction. Practical applications, like noninvasive bioimaging and noninvasive optogenetics, are also presented and prospected.

Fundamentals of Biosensors and Detection Methods

Biosensors have a great impact on our society to enhance the life quality, playing an important role in the development of Point-of-Care (POC) technologies for rapid diagnostics, and monitoring of disease progression. COVID-19 rapid antigen tests, home pregnancy tests, and glucose monitoring sensors represent three examples of successful biosensor POC devices. Biosensors have extensively been used in applications related to the control of diseases, food quality and safety, and environment quality. They can provide great specificity and portability at significantly reduced costs. In this chapter are described the fundamentals of biosensors including the working principles, general configurations, performance factors, and their classifications according to the type of bioreceptors and transducers. It is also briefly illustrated the general strategies applied to immobilize biorecognition elements on the transducer surface for the construction of biosensors. Moreover, the principal detection methods used in biosensors are described, giving special emphasis on optical, electrochemical, and mass-based methods. Finally, the challenges for biosensing in real applications are addressed at the end of this chapter.

Multifunctional Hybrid Hydrogel System Enhanced the Therapeutic Efficacy of Treatments for Postoperative Glioma

Glioma is the most lethal brain tumor with a poor prognosis, and a combination of multiple therapeutic strategies is critical for postoperative glioma treatment. Herein, a multifunctional hybrid hydrogel system (designated as CP&CL@RNP_PTX-Gel) was developed for local treatment of postoperative glioma. The system was composed of self-illuminating chlorin e6 (Ce6) conjugated with luminol molecule (CL)-loaded glioma-targeting paclitaxel prodrug nanoparticles and copper peroxide nanodots (CP NDs) coembedded into a three-dimensional thermosensitive hydroxypropyl chitin hydrogel frame. After injection of CP&CL@RNP_PTX-Gel into the cavity of postoperative glioma, the solution could be cross-linked into the gel as a drug reservoir under body temperature stimulation. Then, the sustained-released CP NDs decomposed into Cu²⁺ and H₂O₂ in the acidic microenvironment of the glioma cells to exert chemodynamic therapy (CDT). Meanwhile, Cu²⁺ could catalyze the self-luminescence of CL to induce photodynamic therapy (PDT) without external excitation light. Moreover, paclitaxel prodrug nanoparticles degraded into paclitaxel to restrain residual glioma cells in response to intracellular reduced glutathione (GSH). The in vitro and in vivo results showed that CP&CL@RNP_PTX-Gel had great potential as a multifunctional hybrid hydrogel system with remarkable therapeutic effects for postoperative glioma treatment via a combination of chemotherapy, CDT, and PDT.

Oxygen Vacancy-Dependent Chemiluminescence: A Facile Approach for Quantifying Oxygen Defects in ZnO

Defect engineering is an effective strategy to improve the catalytic activity of metal oxides, and quantitative characterization of surface defects is thus vital to the understanding and application of metal oxide catalysts. Herein, we found that ZnO nanoparticles with oxygen vacancy could trigger the luminol-H₂O₂ system to emit a strong chemiluminescence (CL), and the CL intensity was strongly dependent on the oxygen vacancy of the ZnO nanoparticles. The mechanism of this CL reaction was discussed by means of the electron-spin resonance spectrum, X-ray photoelectron spectrum (XPS), and CL spectrum. The oxygen vacancy-dependent CL was attributed to the ability of the oxygen vacancy to readily adsorb and further dissociate H₂O₂ into active ^•OH radicals. Taking advantage of this oxygen vacancy-dependent CL, we presented one method for quantifying the oxygen defects in ZnO. Compared with the current evaluation techniques (XPS and Raman spectroscopy), this CL method is rapid, low-cost, and easy to operate. This work introduces the CL technique into the field of material structure-property evaluation, and provides a new approach for exploring the defect function in ZnO defect engineering.

Luminescent Assay for the Screening of SARS-CoV-2 MPro Inhibitors

Since the outbreak of SARS‐CoV‐2 in December 2019 millions of infections have been reported globally. The viral chymotrypsin‐like main protease (M^Pro) exhibits a crucial role in viral replication and represents a relevant target for antiviral drug development. In order to screen potential M^Pro inhibitors we developed a luminescent assay using a peptide based probe containing a cleavage site specific for M^Pro. This assay was validated showing IC₅₀ values similar to those reported in the literature for known M^Pro inhibitors and can be used to screen new inhibitors.

Long-Lasting Chemiluminescence-Based POCT for Portable and Visual Pathogenic Detection and In Situ Inactivation

Bacterial infections seriously threaten human health and also bring huge financial burden. It is critical to construct multifunctional platforms for effectively inactivating bacteria right after point-of-care testing (POCT). Chemiluminescence (CL) bioassays are considered as powerful candidates for POCT as they are free from using an excitation light source, while the flash-type emission limits their further application. Herein, a CL system with long, persistent, and intensive intensity was constructed based on the peroxidase-like property of 4-mercaptophenylboronic acid (MPBA)-functionalized CuSe nanoprobes (CuSe_NPs@MPBA), which improved the detection accuracy and sensitivity. By further integrating a smartphone as an analyzer, quantitative POCT of bacteria was realized with high sensitivity. The limit of detection was as low as 1.25 and 1.01 cfu mL^-1 for Staphylococcus aureus and Escherichia coli detection, respectively. Specifically, bacteria can be eliminated with high efficiency due to excellent photothermal property of CuSe_NPs@MPBA. The developed multifunctional platform also has advantages of simple operation with low cost, suggesting its high potential for use in food safety, environment monitoring, and clinical applications.

CRISPR/Cas12a-Triggered Chemiluminescence Enhancement Biosensor for Sensitive Detection of Nucleic Acids by Introducing a Tyramide Signal Amplification Strategy

CRISPR-based biosensors have attracted increasing attention in accurate and sensitive nucleic acid detection. In this work, we report a CRISPR/Cas12a-triggered chemiluminescence enhancement biosensor for the ultrasensitive detection of nucleic acids by introducing tyramide signal amplification for the first time (termed CRICED). The hybrid chain DNA (crDNA) formed by NH₂-capture DNA (capDNA) and biotin-recognition DNA (recDNA) was preferentially attached to the magnetic beads (MBs), and the streptavidin-HRP was subsequently introduced to obtain MB@HRP-crDNA. In the presence of the DNA target, the activated CRISPR/Cas12a is capable of randomly cutting initiator DNA (intDNA) into vast short products, and thus the fractured intDNA could not trigger the toehold-mediated DNA-strand displacement reaction (TSDR) event with MB@HRP-crDNA. After the addition of tyramine-AP and H₂O₂, abundant HRP-tyramine-AP emerges through the covalent attachment of HRP-tyramine, exhibiting enhanced chemiluminescence (CL) signals or visual image readouts. By virtue of this biosensor, we achieved high sensitivity of synthetic DNA target and amplified DNA plasmid using recombinase polymerase amplification (RPA) as low as 17 pM and single-copy detection, respectively. Our proposed CRICED was further evaluated to test 20 HPV clinical samples, showing a superior sensitivity of 87.50% and specificity of 100.00%. Consequently, the CRICED platform could be an attractive means for ultrasensitive and imaging detection of nucleic acids and holds a promising strategy for the practical application of CRISPR-based diagnostics.

Multicharged cyclodextrin supramolecular assemblies

Multicharged cyclodextrin (CD) supramolecular assemblies, including those based on positively/negatively charged modified mono-6-deoxy-CDs, per-6-deoxy-CDs, and random 2,3,6-deoxy-CDs, as well as parent CDs binding positively/negatively charged guests, have been extensively applied in chemistry, materials science, medicine, biological science, catalysis, and other fields. In this review, we primarily focus on summarizing the recent advances in positively/negatively charged CDs and parent CDs encapsulating positively/negatively charged guests, especially the construction process of supramolecular assemblies and their applications. Compared with uncharged CDs, multicharged CDs display remarkably high antiviral and antibacterial activity as well as efficient protein fibrosis inhibition. Meanwhile, charged CDs can interact with oppositely charged dyes, drugs, polymers, and biomacromolecules to achieve effective encapsulation and aggregation. Consequently, multicharged CD supramolecular assemblies show great advantages in improving drug-delivery efficiency, the luminescence properties of materials, molecular recognition and imaging, and the toughness of supramolecular hydrogels, in addition to enabling the construction of multistimuli-responsive assemblies. These features are anticipated to not only promote the development of CD-based supramolecular chemistry but also contribute to the rapid exploitation of these assemblies in diverse interdisciplinary applications.

A peroxyoxalate chemiluminescence recovery system based on the interaction of N-doped graphene oxide nanosheets and an oligopeptide for ultra-sensitive and selective copper(II) ion detection

In this paper, a peroxyoxalate chemiluminescence (CL) recovery system based on the interaction of N-doped graphene oxide nanosheets (N-GONs) and an oligopeptide for copper(II) ion detection has been reported. N-GONs as an excellent CL enhancer are prepared by the hydrothermal method using citric acid and ammonia, and the morphology and structure are characterized in detail by TEM, XPS, FT-IR and UV/vis, etc. In the bis(2,4,6-trichlorophenyl)oxalate (TCPO) and hydrogen peroxide (TCPO + H₂O₂) CL reaction system, the addition of N-GONs gives a remarkable CL emission, which can be quenched by an oligopeptide composed of ten amino acid residues due to the interaction between the N-GON plane and the oligopeptide strand. While in the presence of copper(II) ion, the quenched CL is recovered gradually along with the addition of copper(II) ion in the system. Based on the above CL reactions, a TCPO + H₂O₂ + N-GONs + oligopeptide CL system is constructed, achieving an ultra-sensitive and selective detection of copper(II) ion in environmental water samples. The detection limit of this method is as low as 0.2 pmol L^-1, which is at least three orders of magnitude lower than other CL methods. The N-GONs and oligopeptide involved in the CL system are environmentally friendly, making it possess potential in the detection of copper(II) ion in environmental water samples.

Cationic AIEgen micelle-improved chemiluminescent H2O2 assay by integrating reactant approach and CRET

The enhancement of chemiluminescence (CL) intensity is significant in the development of chemiluminescent detection systems with improved sensitivity. In this study, a cationic surfactant with an intrinsic aggregation-induced emission emitter (AIEgen) has been applied to boost the CL signal of the horseradish peroxidase-luminol-H₂O₂ system. The formed cationic AIEgen micelles enhance the CL signal in two ways: the electrostatic attraction-mediated enrichment and approach of reactants and the high CRET efficiency between excited luminol radicals and AIEgen in the surfactant backbone. As a result, strong CL intensity is produced. Rapid and sensitive H₂O₂ detection is realized through the proposed cationic AIEgen micelle-containing chemiluminescent system with a limit of detection of 100 nM. The favourable selectivity over other possible interferents including metal ions and anions is due to the specific chemical reaction. Practical H₂O₂ analysis of thawing water samples with high accuracy using the proposed chemiluminescent platform is realized and is consistent with standard methods.

Development of a Coelenterazine Derivative with Enhanced Superoxide Anion-Triggered Chemiluminescence in Aqueous Solution

Superoxide anion is a reactive oxygen species (ROS) of biological interest. More specifically, it plays a role in intra- and intercellular signaling, besides being associated with conditions such as inflammation and cancer. Given this, efforts have been made by the research community to devise new sensing strategies for this ROS species. Among them, the chemiluminescent reaction of marine Coelenterazine has been employed as a sensitive and dynamic probing approach. Nevertheless, chemiluminescent reactions are typically associated with lower emissions in aqueous solutions. Herein, here we report the synthesis of a new Coelenterazine derivative with the potential for superoxide anion sensing. Namely, this novel compound is capable of chemiluminescence in a dose-dependent manner when triggered by this ROS species. More importantly, the light-emission intensities provided by this derivative were relevantly enhanced (intensities 2.13 × 101 to 1.11 × 104 times higher) in aqueous solutions at different pH conditions when compared to native Coelenterazine. The half-life of the chemiluminescent signal is also greatly increased for the derivative. Thus, a new chemiluminescence molecule with significant potential for superoxide anion sensing was discovered and reported for the first time.

Polymeric agents for activatable fluorescence, self-luminescence and photoacoustic imaging

Numerous polymeric agents have been widely applied in biology and medicine by virtue of the facile chemical modification, feasible nano-engineering approaches and fine-tuned pharmacokinetics. To endow polymeric imaging agents with ability to monitor and measure subtle molecular or cellular alterations at diseased sites, activatable polymeric probes that can elicit signal changes in response to biomolecular interactions or the analytes of interest have to be developed. Herein, this review aims to provide a systemic interpretation and summarization of the design methodology and imaging utility of recently emerged activatable polymeric probes. An introduction of activatable probes allowing for precise imaging and classification of polymeric imaging agents is reported first. Then, we give a detailed discussion of the contemporary design approaches toward activatable polymeric probes in diverse imaging modes for the detection of various stimuli and their imaging applications. Finally, current challenges and future advances are discussed and highlighted.

Conjugated Oligoelectrolytes for Long-Term Tumor Tracking with Incremental NIR-II Emission

The design and synthesis of the near-infrared (NIR)-II emissive conjugated oligoelectrolyte COE-BBT are reported. COE-BBT has a solubility in aqueous media greater than 50 mg mL^-1 , low toxicity, and a propensity to intercalate lipid bilayers, wherein it exhibits a higher emission quantum yield relative to aqueous media. Addition of COE-BBT to cells provides two emission channels, at ≈500 and ≈1020 nm, depending on the excitation wavelength, which facilitates in vitro confocal microscopy and in vivo animal imaging. The NIR-II emission of COE-BBT is used to track intracranial and subcutaneous tumor progression in mice. Of relevance is that the total NIR-II intensity increases over time. This phenomenon is attributed to a progressive attenuation of a COE-BBT self-quenching effect within the cells due to the expected dye dilution per cell as the tumor proliferates.