Multibranched Linear DNA-Controlled Assembly of Silver Nanoclusters and Their Applications in Aptamer-Based Cell Recognition

The Advancing Role of Nanocomposites in Cancer Diagnosis and Treatment

The relentless pursuit of effective cancer diagnosis and treatment strategies has led to the rapidly expanding field of nanotechnology, with a specific focus on nanocomposites. Nanocomposites, a combination of nanomaterials with diverse properties, have emerged as versatile tools in oncology, offering multifunctional platforms for targeted delivery, imaging, and therapeutic interventions. Nanocomposites exhibit great potential for early detection and accurate imaging in cancer diagnosis. Integrating various imaging modalities, such as magnetic resonance imaging (MRI), computed tomography (CT), and fluorescence imaging, into nanocomposites enables the development of contrast agents with enhanced sensitivity and specificity. Moreover, functionalizing nanocomposites with targeting ligands ensures selective accumulation in tumor tissues, facilitating precise imaging and diagnostic accuracy. On the therapeutic front, nanocomposites have revolutionized cancer treatment by overcoming traditional challenges associated with drug delivery. The controlled release of therapeutic agents from nanocomposite carriers enhances drug bioavailability, reduces systemic toxicity, and improves overall treatment efficacy. Additionally, the integration of stimuli-responsive components within nanocomposites enables site-specific drug release triggered by the unique microenvironment of the tumor. Despite the remarkable progress in the field, challenges such as biocompatibility, scalability, and long-term safety profiles remain. This article provides a comprehensive overview of recent developments, challenges, and prospects, emphasizing the transformative potential of nanocomposites in revolutionizing the landscape of cancer diagnostics and therapeutics. In Conclusion, integrating nanocomposites in cancer diagnosis and treatment heralds a new era for precision medicine.

DNA framework signal amplification platform-based high-throughput systemic immune monitoring

Systemic immune monitoring is a crucial clinical tool for disease early diagnosis, prognosis and treatment planning by quantitative analysis of immune cells. However, conventional immune monitoring using flow cytometry faces huge challenges in large-scale sample testing, especially in mass health screenings, because of time-consuming, technical-sensitive and high-cost features. However, the lack of high-performance detection platforms hinders the development of high-throughput immune monitoring technology. To address this bottleneck, we constructed a generally applicable DNA framework signal amplification platform (DSAP) based on post-systematic evolution of ligands by exponential enrichment and DNA tetrahedral framework-structured probe design to achieve high-sensitive detection for diverse immune cells, including CD4+, CD8+ T-lymphocytes, and monocytes (down to 1/100 μl). Based on this advanced detection platform, we present a novel high-throughput immune-cell phenotyping system, DSAP, achieving 30-min one-step immune-cell phenotyping without cell washing and subset analysis and showing comparable accuracy with flow cytometry while significantly reducing detection time and cost. As a proof-of-concept, DSAP demonstrates excellent diagnostic accuracy in immunodeficiency staging for 107 HIV patients (AUC > 0.97) within 30 min, which can be applied in HIV infection monitoring and screening. Therefore, we initially introduced promising DSAP to achieve high-throughput immune monitoring and open robust routes for point-of-care device development.

Asymmetric Hairpins DNA Encapsulated Silver Nanoclusters for In Situ Fluorescence Imaging of Fusion Gene Isoforms in Bone Marrow

Rapid and accurate imaging of the BCR/ABL fusion gene isoforms (e.g., e13a2, e14a2 and co-expression type) of chronic myeloid leukemia (CML) is of vital importance to first-line drug selection, but there is no assay that meets clinical needs (e.g., clinical kits > 18 h without isoforms information). Herein, an in situ imaging platform is developed for the rapid and accurate detection of CML fusion gene isoforms using asymmetric sequence-enhanced hairpins DNA encapsulated silver nanoclusters (ADHA) and catalyzed hairpin assembly (CHA). The specific detection of e13a2 and e14a2 fusion gene isoforms with detection limits of 19.2 am (11.558 copies µL-1 ) and 32.56 am (19.601 copies µL-1 ) in one-pot is achieved. The feasibility of the developed assay for real-world applications are demonstrated by one-step fluorescence imaging (40 min) of e13a2, e14a2 and co-expression type in bone marrow quantitatively (International Standard: 15.66%-168.878%) and further validated by cDNA-sequencing. This work suggests that the developed imaging platform holds great potential for rapid identification of the fusion gene isoforms and isoform related treatment monitoring.

A cell-surface-anchored DNA probe coupled with hybridization chain reaction enzyme-free dual signal amplification for sensitive electrochemical detection of the cellular microenvironment

The cellular microenvironment plays key roles in regulating physiological processes. However, it is still a challenge to detect it with quantification. Here, a simple, biocompatible, and universal strategy based on cell surface-anchored specific DNAzymes and hybridization chain reaction enzyme-free signal amplification for cellular microenvironment electrochemical detection is presented. In this strategy, the cell could be captured on the surface of the electrode via aptamer-target recognition. On the other hand, the DNAzyme hybridized with the substrate strand as a metal ion probe was anchored on the surface of the cell. In the presence of metal ions, the substrate strand could be cleaved into two fragments by the DNAzyme and released from the cell surface. Then, the DNA modified gold nanoparticles (AuNPs) could be captured on the electrode. Subsequently, an alternative hybridization reaction of two hairpin probes was triggered by the carried initiators forming nicked double helices. For signal readout, hemin could be inserted into the double-helix DNA long chain via electrostatic interaction, which could electro-reduce hydrogen peroxide to generate an electrochemical signal. Based on the intrinsic advantages of DNAzymes, including rapid kinetics, high sensitivity, and high selectivity, and the signal amplification strategy, this method should be able to monitor and semi-quantify target metal ions in the cellular microenvironment. Furthermore, this method shows potential for various targets by employing different DNA probes in the cellular microenvironment, providing a platform for bioanalysis.

Dual-channel fluorescence detection of antibiotic resistance genes based on DNA-templated silver nanoclusters

The aqueous environment is an ideal site for the generation and transmission of antibiotic resistance genes (ARGs), and has become a sink for multiple ARGs. Detection of multiple ARGs in one-pot by a simple method is essential to control the spread of antibiotic resistance. Herein, we developed a novel fluorescence sensing strategy based on chameleon DNA-templated silver nanoclusters (AgNCs) to achieve simultaneous detection of two ARGs (tet-A and sul-1). A DNA fluorescent probe with AgNCs stabilized at both termini and another DNA probe carried enhancer sequences were designed. The hybridization of the target ARGs and probes can form an infinitely extended linear DNA structure containing multi-branched AgNCs beacons, and the chameleon AgNCs approach the fluorescence enhancer sequence, thereby realizing the transduction and amplification of green and red fluorescence signals. Through this strategy, we successfully achieved highly specific detection of two ARGs with the LOD of 0.45 nM for tet-A and 0.32 nM for sul-1. In addition, the strategy still had good applicability in the detection of actual samples containing complex components. In this study, fluorescent DNA-AgNCs were applied to the rapid, enzyme-free and reliable detection of ARGs for the first time. The excellent performance of the simultaneous detection of two ARGs displayed that this method can be used to simultaneously analyze different types of ARGs, indicating its great potential in rapid screening and quantitative detection of ARGs in various environmental medias.

Recent Advances in Aptamer-Based Sensors for Sensitive Detection of Neurotransmitters

In recent years, there has been an increased demand for highly sensitive and selective biosensors for neurotransmitters, owing to advancements in science and technology. Real-time sensing is crucial for effective prevention of neurological and cardiovascular diseases. In this review, we summarise the latest progress in aptamer-based biosensor technology, which offers the aforementioned advantages. Our focus is on various biomaterials utilised to ensure the optimal performance and high selectivity of aptamer-based biosensors. Overall, this review aims to further aptamer-based biosensor technology.

Revealing the effects of ligands of silver nanoclusters on the interactions between them and ctDNA: Abstraction to visualization

Silver nanoclusters (AgNCs) have been widely applied in the field of biology, drug therapy and cell imaging in the last decade. In order to study the biosafety of AgNCs, GSH-AgNCs and DHLA-AgNCs were synthesized using glutathione (GSH) and dihydrolipoic acid (DHLA) as ligands, and their interactions with calf thymus DNA (ctDNA) from abstraction to visualization were studied. The results of spectroscopy, viscometry and molecular docking demonstrated that GSH-AgNCs mainly bound to ctDNA in a groove mode, while DHLA-AgNCs were both groove and intercalation binding. Fluorescence experiments suggested that the quenching mechanism of both AgNCs to the emission of ctDNA-probe were both in static mode, and thermodynamic parameters demonstrated that the main forces between GSH-AgNCs and ctDNA were hydrogen bonds and van der Waals forces, while hydrogen bonds and hydrophobic forces contributed to the binding of DHLA-AgNCs to ctDNA. The binding strength demonstrated that DHLA-AgNCs bound to ctDNA more strongly than that of GSH-AgNCs. The results of circular dichroism (CD) spectroscopy reflected small effects of both AgNCs on the structure of ctDNA. This study will support the theoretical foundation for the biosafety of AgNCs and have a guiding significance for the preparation and application of AgNCs.

Dual Lewis Acid- and Base-Responsive Terpyridine-Based Hydrogel: Programmable and Spatiotemporal Regulation of Fluorescence for Chemical-Based Information Security

A huge amount of data inundated in our daily life; there is an ever-increasing need to develop a new strategy of information encryption-decryption-erasing. Herein, a polymeric DCTpy/PAM hydrogel has been fabricated to store information via controllable Eu³⁺/Zn²⁺ ionoprinting for hierarchical and multidimensional information decryption. Eu³⁺ and Zn²⁺ have a competition and dynamic interaction toward DCTpy under NH₃ stimuli in the polymeric DCTpy/PAM hydrogel network. The Eu(III)/Zn(II)@DCTpy/PAM hydrogel exhibits light red fluorescence of Eu³⁺ due to the antenna effect. Upon the addition of NH₃, dissociation of the Eu³⁺-DCTpy complex takes place, and the Zn(II)/DCTpy/NH₃ complex is formed with both ICT (intramolecular charge-transfer) and PET (photo-induced electron-transfer) process characteristics that exhibits yellow emission color. Subsequently, HCl can quench the fluorescence of the resulting hydrogel. By integrating transparency, adhesiveness, and programmable stimuli responsiveness of the hydrogel blocks in to one system, complex, multistage, and time-controlled information storage-encryption-decryption-erasing in sequence with multidimensions is illustrated via the molecule diffusion method. This work provides a novel and representative strategy in fabricating information encryption-decryption-erasing materials with high capacity and complexity by a simple terpyridine-based hydrogel.

A versatile and convenient tool for regulation of DNA strand displacement and post-modification on pre-fabricated DNA nanodevices

Toehold-mediated strand displacement and its regulatory tools are fundamental for DNA nanotechnology. However, current regulatory tools all need to change the original sequence of reactants, making the regulation inconvenient and cumbersome. More importantly, the booming development of DNA nanotechnology will soon promote the production of packaged and batched devices or circuits with specified functions. Regarding standardized, packaged DNA nanodevices, access to personalized post-modification will greatly help users, whereas none of the current regulatory tools can provide such access, which has greatly constrained DNA nanodevices from becoming more powerful and practical. Herein, we developed a novel regulation tool named Cap which has two basic functions of subtle regulation of the reaction rate and erasability. Based on these functions, we further developed three advanced functions. Through integration of all functions of Cap and its distinct advantage of working independently, we finally realized personalized tailor-made post-modification on pre-fabricated DNA circuits. A pre-fabricated dual-output DNA circuit was successfully transformed into an equal-output circuit, a signal-antagonist circuit and a covariant circuit according to our requirements. Taken together, Cap is easy to design and generalizable for all strand displacement-based DNA nanodevices. We believe the Cap tool will be widely used in regulating reaction networks and personalized tailor-made post-modification of DNA nanodevices.

Multi pathogenic microorganisms determination using DNA composites-encapsulated DNA silver nanocluster/graphene oxide-based system through rolling cycle amplification

A multi pathogenic microorganisms determination method is reported using DNA composites encapsulated DNA silver nanocluster (AgNCs)/graphene oxide (GO)-based system through rolling cycle (RCA) amplification. Firstly, two different RCA-based DNA composites are assembled, coupled with thousands of DNA-stabilized AgNCs probe and ssDNA aptamer specific for two pathogen bacteria targets. GO was then introduced into the system to capture ssDNA aptamer of DNA composites and as a selective fluorescence quencher of DNA/AgNCs. Upon recognizing the target bacteria, ssDNA aptamer part would combine with bacteria and release from the surface of GO. Thus, DNA/AgNCs of RCA-based DNA composites can generate strong fluorescence signal. With the fluorescent report of RCADNA-AgNCs/530 and RCADNA-AgNCs/625, the assay successfully detect Escherichia coli and Staphylococcus aureus at concentrations as low as 38 CFU/mL, and a highly selective and efficient sensing platform was achieved. Therefore, this RCA/DNA-AgNCs/GO-based platform shows excellent application in multi pathogenic microorganisms determination and potential clinic therapy.