Y-Shaped Backbone-Rigidified DNA Tiles for the Construction of Supersized Nondeformable Tetrahedrons for Precise Cancer Therapies.

While engineered DNA nanoframeworks have been extensively exploited for delivery of diagnostic and therapeutic regents, DNA tiling-based DNA frameworks amenable to applications in living systems lag much behind. In this contribution, by developing a Y-shaped backbone-based DNA tiling technique, we assemble Y-shaped backbone-rigidified supersized DNA tetrahedrons (RDT) with 100% efficiency for precisely targeted tumor therapy. RDT displays unparalleled rigidness and unmatched resistance to nuclease degradation so that it almost does not deform under the force exerted by the atomic force microscopy tip, and the residual amount is not less than 90% upon incubating in biological media for 24 h, displaying at least 11.6 times enhanced degradation resistance. Without any targeting ligand, RDT enters the cancer cell in a targeted manner, and internalization specificity is up to 15.8. Moreover, 77% of RDT objects remain intact within living cells for 14 h. The drug loading content of RDT is improved by 4-8 times, and RDT almost 100% eliminates the unintended drug leakage in a stimulated physiological medium. Once systemically administrated into HeLa tumor-bearing mouse models, doxorubicin-loaded RDTs preferentially accumulate in tumor sites and efficiently suppress tumor growth without detectable off-target toxicity. The Y-DNA tiling technique offers invaluable insights into the development of structural DNA nanotechnology for precise medicine.

Type I/type III IFN and related factors regulate JEV infection and BBB endothelial integrity.

BACKGROUND: Japanese encephalitis virus (JEV) remains a predominant cause of Japanese encephalitis (JE) globally. Its infection is usually accompanied by disrupted blood‒brain barrier (BBB) integrity and central nervous system (CNS) inflammation in a poorly understood pathogenesis. Productive JEV infection in brain microvascular endothelial cells (BMECs) is considered the initial event of the virus in penetrating the BBB. Type I/III IFN and related factors have been described as negative regulators in CNS inflammation, whereas their role in JE remains ambiguous. METHODS: RNA-sequencing profiling (RNA-seq), real-time quantitative PCR, enzyme-linked immunosorbent assay, and Western blotting analysis were performed to analyze the gene and protein expression changes between mock- and JEV-infected hBMECs. Bioinformatic tools were used to cluster altered signaling pathway members during JEV infection. The shRNA-mediated immune factor-knockdown hBMECs and the in vitro transwell BBB model were utilized to explore the interrelation between immune factors, as well as between immune factors and BBB endothelial integrity. RESULTS: RNA-Seq data of JEV-infected hBMECs identified 417, 1256, and 2748 differentially expressed genes (DEGs) at 12, 36, and 72 h post-infection (hpi), respectively. The altered genes clustered into distinct pathways in gene ontology (GO) terms and KEGG pathway enrichment analysis, including host antiviral immune defense and endothelial cell leakage. Further investigation revealed that pattern-recognition receptors (PRRs, including TLR3, RIG-I, and MDA5) sensed JEV and initiated IRF/IFN signaling. IFNs triggered the expression of interferon-induced proteins with tetratricopeptide repeats (IFITs) via the JAK/STAT pathway. Distinct PRRs exert different functions in barrier homeostasis, while treatment with IFN (IFN-ß and IFN-λ1) in hBMECs stabilizes the endothelial barrier by alleviating exogenous destruction. Despite the complex interrelationship, IFITs are considered nonessential in the IFN-mediated maintenance of hBMEC barrier integrity. CONCLUSIONS: This research provided the first comprehensive description of the molecular mechanisms of host‒pathogen interplay in hBMECs responding to JEV invasion, in which type I/III IFN and related factors strongly correlated with regulating the hBMEC barrier and restricting JEV infection. This might help with developing an attractive therapeutic strategy in JE.

Electrocardiographic Characteristics of Ventricular Arrhythmias Originating from Different Areas Adjacent to the Mitral Annulus.

BACKGROUND: This study aimed to explore the electrocardiographic (ECG) characteristics of ventricular arrhythmias (VAs) arising from epicardial and endocardial areas adjacent to the mitral annulus (MA). METHODS: This study involved 283 patients with MA-VAs who received radiofrequency catheter ablation at the center. The ECG characteristics of these patients were analyzed retrospectively. RESULTS: The origin of MA-VAs was judged based on the ECG variables. Among all MA-VAs, intrinsicoid deflection time (IDT) > 77 ms or maximum deflection index (MDI) > 0.505 predicted the VAs arising from the epicardium (sensitivity of 70.20% and 73.51%, specificity of 94.70% and 82.58%, positive predictive value (PPV) of 93.81% and 82.84%, and negative predictive value (NPV) of 73.53% and 73.15%). Among all epicardial MA-VAs, the RV1/RV2 ratio > 0.87 predicted the VAs originating from the epicardial anteroseptal wall adjacent to the MA. It had a sensitivity, specificity, PPV, and NPV of 62.86%, 98.06%, 91.67%, and 88.60%, respectively. Among all endocardial MA-VAs, Q(q)R(r) morphology in lead V1 predicted the VAs arising from the endocardial septal wall adjacent to the MA. It had a sensitivity, specificity, PPV, and NPV of 92.98%, 100%, 100%, and 94.94%, respectively. Among all endocardial septal MA-VAs, a predominant positive wave in lead II and a predominant negative wave in lead III predicted the VAs arising from the endocardial midseptal portion adjacent to the MA. It had a sensitivity, specificity, PPV, and NPV of 86.04%, 100%, 100%, and 70.00%, respectively. CONCLUSION: the ECG characteristics of VAs from the different sites adjacent to the MA can enable judging the arrhythmia's origin and designing the ablation plan accordingly.

Contour integration deficits at high spatial frequencies in children treated for anisometropic amblyopia.

Purpose: This study was conducted to reexamine the question of whether children treated for anisometropic amblyopia have contour integration deficits. To do so, we used psychophysical methods that require global contour processing while minimizing the influence of low-level deficits: visibility, shape perception, and positional uncertainty. Methods: Thirteen children with anisometropic amblyopia (age: 10.1 ± 1.8 years) and thirteen visually normal children (age: 10.8 ± 2.0 years) participated in this study. The stimuli were closed figures made up of Gabor patches either in noise or on a blank field. The contrast thresholds to detect a circular contour on a blank field, as well as the thresholds of aspect ratio and contour element number to discriminate a circular or elliptical contour in noise, were measured at Gabor spatial frequencies of 1.5, 3, and 6 cpd for amblyopic eyes (AEs), fellow eyes (FEs), and normal control eyes. Visual acuities and contrast sensitivity functions for AEs and FEs and the Randot stereoacuity were measured before testing. Results: The AEs showed contrast deficits and degraded shape perception compared to the FEs at higher spatial frequencies (6 cpd). When the influence of abnormal contrast sensitivity and shape perception were minimized, the AEs showed contour integration deficits at spatial frequencies 3 and 6 cpd. These deficits were not related to basic losses in contrast sensitivity and acuity, stereoacuity, and visual crowding. Besides, no significant difference was found between the fellow eyes of the amblyopic children and the normal control eyes in the performance of contour integration. Conclusion: After eliminating or compensating for the low-level deficits, children treated for anisometropic amblyopia still show contour integration deficits, primarily at higher spatial frequencies, which might reflect the deficits in global processing caused by amblyopia. Contour integration deficits are likely independent of spatial vision deficits. Refractive correction and/or occlusion therapies may not be sufficient to fully restore contour integration deficits, which indicates the need for the development of clinical treatments to recover these deficits.

The impact of training on the inner-outer asymmetry in crowding.

Inner-outer asymmetry, where the outer flanker induces stronger crowding than the inner flanker, is a hallmark property of visual crowding. It is unclear the contribution of inner-outer asymmetry to the pattern of crowding errors (biased predominantly toward the flanker identities) and the role of training on crowding errors. In a typical radial crowding display, 20 observers were asked to report the orientation of a target Gabor (7.5° eccentricity) flanked by either an inner or outer Gabor along the horizontal meridian. The results showed that outer flanker conditions induced stronger crowding, accompanied by assimilative errors to the outer flanker for similar target/flanker elements. In contrast, the inner flanker condition exhibited weaker crowding, with no significant patterns of crowding errors. A population coding model showed that the flanker weights in the outer flanker condition were significantly higher than those in the inner flanker condition. Nine observers continued to train the outer flanker condition for four sessions. Training reduced inner-outer asymmetry and reduced flanker weights to the outer flanker. The learning effects were retained over 4 to 6 months. Individual differences in the appearance of crowding errors, the strength of inner-outer asymmetry, and the training effects were evident. Nevertheless, our findings indicate that different crowding mechanisms may be responsible for the asymmetric crowding effects induced by inner and outer flankers, with the outer flankers dominating the appearance more than the inner ones. Training reduces inner-outer asymmetry by reducing target/flanker confusion, and learning is persistent over months, suggesting that perceptual learning has the potential to improve visual performance by promoting neural plasticity.

Functional characterization and clinical implication of a novel epidemic carbapenem-resistant Acinetobacter baumannii genetic marker.

OBJECTIVES: The aim of the study was to evaluate the distribution and function of contact-dependent growth inhibition (CDI) systems associated with carbapenem-resistant Acinetobacter baumannii (CRAB) isolates. METHODS: Isolates were examined by multilocus sequence typing (MLST) and polymerase chain reaction (PCR) for the presence of CDI genes in CRAB and carbapenem-susceptible A. baumannii (CSAB) from patients with invasive disease in a medical center in Taiwan. Inter-bacterial competition assays were performed to characterize the in vitro function of the CDI system. RESULTS: A total of 89 (61.0%) CSAB and 57 (39.0%) CRAB isolates were collected and examined. ST787 (20/57; 35.1%) was the predominant sequence type among CRAB, followed by ST455 (10/57; 17.5%). More than half the CRAB (56.1%, 32/57) belonged to CC455 and more than one third (38.6%, 22/57) to CC92. A novel CDI system, cdiTYTH1, was found in 87.7% (50/57) of the CRAB but in only 1.1% (1/89) of the CSAB isolates (P<0.00001). The cdiTYTH1 was also identified in 94.4% (17/18) of previously genome-sequenced CRAB isolates and only one CSAB isolate from Taiwan. Two other previously reported CDI (cdi19606-1 and cdi19606-2) were not found in these isolates, except both were found in one CSAB. All six CRAB without cdiTYTH1 showed growth inhibition by a CSAB carrying cdiTYTH1 in vitro. All clinical CRAB isolates belonging to the predominant CC455 carried the newly identified cdiTYTH1. CONCLUSIONS: This CDI system was widespread in CRAB clinical isolates and appeared to be an epidemic genetic marker for CRAB in Taiwan. The cdiTYTH1 was functional in vitro in bacterial competition assay.

Wheel drive-based DNA sensing system for highly specific and rapid one-step detection of MiRNAs at the attomolar level.

With the use of DNA as building blocks, a variety of microRNA amplification-based sensing systems have been developed. Nevertheless, ultrasensitive, selective and rapid detection of microRNAs with a high signal-to-background ratio and point mutation discrimination ability remains a challenge. Herein, we propose a novel wheel drive-based DNA sensing system (NWDS) based on a self-assembled, self-quenched nanoprobe (SQP) to conduct highly specific and ultrasensitive one-step measurement of microRNAs. In this work, a signalling recognition DNA hairpin (DH) sequence with a self-complementary stem domain of 14 base pairs was used, which contained three functional regions, namely a recognition region for the target miRNA-21, a sticky region with 9 complementary nucleotides to the 3'terminus of a DNA wheel (DW) and a region for the hybridization with a quenching DNA primer (DP). The SQP was ingeniously self-assembled at room temperature by the DH and DP, which was capable of eliminating unwanted background signals. MiRNA-21 was employed as a target model to specifically activate the SQP, leading to specific hybridization between the HP and DW. With the assistance of a polymerase, an SQP-based wheel driving took place to induce hybridization/polymerization displacement cycles, initiating target recycling and DP displacement. As a result, a large amount of the newly formed hybrid SQP/DW accumulated to generate a substantially enhanced fluorescence signal. In this way, the newly proposed NWDS exhibits ultrasensitivity with a detection limit of 5.62 aM across a wide linear dynamic response range up to 200 nM, excellent selectivity with the capability to discriminate homologous miRNAs and one-base, two-base and three-base mismatched sequences, and an outstanding analytical performance in complex systems. In addition, the significant simultaneous advantages of one-step operation, rapid detection within 15 min and a high signal-to-background ratio of 26 offer a unique opportunity to promote the early diagnosis of cancer-related diseases and molecular biological analysis.

Differentiation Between Internal Carotid Artery Hypoplasia and Acquired Narrowing by Neurovascular Ultrasound: Case Series and Literature Review.

Uniformly narrowed internal carotid artery (ICA) without proximal steno-occlusion or parietal anomalies is often subject to misdiagnosis due to lack of awareness. We combined our experiences of 4 cases with 29 previously published cases to form a retrospective series including 18 cases of ICA hypoplasia and 15 cases of ICA acquired narrowing. The ultrasonic manifestations of ICA acquired narrowing and ICA hypoplasia are extremely similar, but narrowed ICA without intracranial occlusion or bottle-neck-sign highly indicates ICA hypoplasia, whereas moyamoya vessels favor ICA acquired narrowing, thus promoting the understanding of and discriminability between the two on neurovascular ultrasound.

Overcoming High Impedance in the Transitional Area of the Distal Great Cardiac Vein during Radiofrequency Catheter Ablation of Ventricular Arrhythmia.

(1) Background: Radiofrequency catheter ablation (RFCA) is an essential treatment for ventricular arrhythmia (VA). However, high impedance in the transitional area of the distal great cardiac vein (TAODGCV) often leads to ablation failure. This study aimed to explore the factors influencing impedance and identify effective ways to reduce impedance. (2) Methods: A total of 156 patients with VA arising from the TAODGCV received RFCA therapy at our center from October 2009 to August 2021 and were retrospectively analyzed. Local impedance variation during RFCA was monitored, recorded, and analyzed. (3) Results: The impedance increased from the proximal to distal portions of the TAODGCV and decreased by increasing the saline flow rate at the same site. To overcome high impedance, we implemented the following strategies: (1) Reset the upper limit impedance to 300 Ω and accelerate the saline flow rate to 60 mL/min (effective in 118 of 144 patients); (2) turn off the upper limit impedance (effective in eleven of 21 patients); (3) use high-flow-rate irrigation devices (effective in five of 15 patients); and (4) increase the upper limit temperature (effective in six of ten patients). (4) Conclusions: In the TAODGCV, local impedance is mainly influenced by the target site location and saline flow rate. We concluded several methods to overcome the high impedance and contribute to a successful ablation.

EGFR Activation Impairs Antiviral Activity of Interferon Signaling in Brain Microvascular Endothelial Cells During Japanese Encephalitis Virus Infection.

The establishment of Japanese encephalitis virus (JEV) infection in brain microvascular endothelial cells (BMECs) is thought to be a critical step to induce viral encephalitis with compromised blood-brain barrier (BBB), and the mechanisms involved in this process are not completely understood. In this study, we found that epidermal growth factor receptor (EGFR) is related to JEV escape from interferon-related host innate immunity based on a STRING analysis of JEV-infected primary human brain microvascular endothelial cells (hBMECs) and mouse brain. At the early phase of the infection processes, JEV induced the phosphorylation of EGFR. In JEV-infected hBMECs, a rapid internalization of EGFR that co-localizes with the endosomal marker EEA1 occurred. Using specific inhibitors to block EGFR, reduced production of viral particles was observed. Similar results were also found in an EGFR-KO hBMEC cell line. Even though the process of viral infection in attachment and entry was not noticeably influenced, the induction of IFNs in EGFR-KO hBMECs was significantly increased, which may account for the decreased viral production. Further investigation demonstrated that EGFR downstream cascade ERK, but not STAT3, was involved in the antiviral effect of IFNs, and a lowered viral yield was observed by utilizing the specific inhibitor of ERK. Taken together, the results revealed that JEV induces EGFR activation, leading to a suppression of interferon signaling and promotion of viral replication, which could provide a potential target for future therapies for the JEV infection.

IFIT2-depleted metastatic oral squamous cell carcinoma cells induce muscle atrophy and cancer cachexia in mice.

BACKGROUND: Interferon-induced protein with tetratricopeptide repeat 2 (IFIT2) is a reported metastasis suppressor in oral squamous cell carcinoma (OSCC). Metastases and cachexia may coexist. The effect of cancer metastasis on cancer cachexia is largely unknown. We aimed to address this gap in knowledge by characterizing the cachectic phenotype of an IFIT2-depleted metastatic OSCC mouse model. METHODS: Genetically engineered and xenograft tumour models were used to explore the effect of IFIT2-depleted metastatic OSCC on cancer cachexia. Muscle and organ weight changes, tumour burden, inflammatory cytokine profiles, body composition, food intake, serum albumin and C-reactive protein (CRP) levels, and survival were assessed. The activation of the IL6/p38 pathway in atrophied muscle was measured. RESULTS: IFIT2-depleted metastatic tumours caused marked body weight loss (-18.2% vs. initial body weight, P < 0.001) and a poor survival rate (P < 0.01). Skeletal muscles were markedly smaller in IFIT2-depleted metastatic tumour-bearing mice (quadriceps: -28.7%, gastrocnemius: -29.4%, and tibialis: -24.3%, all P < 0.001). Tumour-derived circulating granulocyte-macrophage colony-stimulating factor (+772.2-fold, P < 0.05), GROα (+1283.7-fold, P < 0.05), IL6 (+245.8-fold, P < 0.001), IL8 (+616.9-fold, P < 0.001), IL18 (+24-fold, P < 0.05), IP10 (+18.8-fold, P < 0.001), CCL2 (+439.2-fold, P < 0.001), CCL22 (+9.1-fold, P < 0.01) and tumour necrosis factor α (+196.8-fold, P < 0.05) were elevated in IFIT2-depleted metastatic tumour-bearing mice. Murine granulocyte colony-stimulating factor (+61.4-fold, P < 0.001) and IL6 (+110.9-fold, P < 0.01) levels were significantly increased in IFIT2-depleted metastatic tumour-bearing mice. Serum CRP level (+82.1%, P < 0.05) was significantly increased in cachectic shIFIT2 mice. Serum albumin level (-26.7%, P < 0.01) was significantly decreased in cachectic shIFIT2 mice. An assessment of body composition revealed decreased fat (-81%, P < 0.001) and lean tissue (-21.7%, P < 0.01), which was consistent with the reduced food intake (-19.3%, P < 0.05). Muscle loss was accompanied by a smaller muscle cross-sectional area (-23.3%, P < 0.05). Muscle atrophy of cachectic IFIT2-depleted metastatic tumour-bearing mice (i.v.-shIFIT2 group) was associated with elevated IL6 (+2.7-fold, P < 0.05), phospho-p38 (+2.8-fold, P < 0.05), and atrogin-1 levels (+2.3-fold, P < 0.05) in the skeletal muscle. Neutralization of IL6 rescued shIFIT2 conditioned medium-induced myotube atrophy (+24.6%, P < 0.01). CONCLUSIONS: Our results suggest that the development of shIFIT2 metastatic OSCC lesions promotes IL6 production and is accompanied by the loss of fat and lean tissue, anorexia, and muscle atrophy. This model is appropriate for the study of OSCC cachexia, especially in linking metastasis with cachexia.

Tumor-targeting [2]catenane-based grid-patterned periodic DNA monolayer array for in vivo theranostic application.

DNA nanotechnology is often used to build various nano-structures for signaling and/or drug delivery, but it essentially suffers from several major limitations, such as a large number of DNA strands and limited targeting ligands. Moreover, there is no report on in vivo two-dimensional DNA arrays because of various technical challenges. By cross-catenating two palindromic DNA rings, herein, we demonstrate a catenane-based grid-patterned periodic DNA monolayer array ([2]GDA) capable of preferentially accumulating in tumor tissues without any targeting ligands, with a thickness equal to the double-helical DNA monolayer (nearly 2 nm). The structural flexibility of [2]GDA enabled it to fold into a spherical object in solution, favoring cellular uptake. Thus, its cellular internalization activity was comparable with that of the commercial lipofectamine 3000. Moreover, [2]GDA retained the structural integrity over 24 h incubation in biological solutions, achieving a 360-fold improvement in in vivo stability. Significantly, anticancer drug-loaded [2]GDA exhibits desirable therapeutic efficacy in tumor-bearing animals without detectable side effects.

Modification of soy protein isolate by Maillard reaction and its application in microencapsulation of Limosilactobacillusreuteri.

Limosilactobacillusreuteri was encapsulated using Maillard-reaction-products (MRPs) of soy protein isolate (SPI) and α-lactose monohydrate by freeze-drying. The mixed solution of SPI and α-lactose monohydrate was placed in a water bath at 89°C for 160 min for Maillard reaction, and then freeze-dried to obtain MRPs. The effects of Maillard reaction on functional characteristics of MRPs and the properties of MRPs-microcapsules were studied. SDS-PAGE indicated that SPI subunit reacted with lactose to form a polymer, and the band of MRPs disappeared around the molecular weights of 33, 40, 63, and 100 kDa. Compared with SPI, the emulsion stability, emulsion activity, foaming capacity, foam stability, and gel strength of MRPs were increased by 259%, 55.71%, 82.32%, 58.53%, and 3266%, respectively. The results of Fourier transform infrared spectroscopy, circular dichroism spectroscopy, and scanning electron micrographs confirmed that the protein structure also changed significantly. Then, MRPs were used as wall material to prepare L. reuteri microcapsules. Physical properties and viable counts of L. reuteri during the simulated gastrointestinal digestion and storage period were determined. The particle size of MRPs-microcapsules (68 µm) was smaller than that of SPI-microcapsules (91 µm). The viable counts of L. reuteri in simulated gastrointestinal digestion and after storage for 30 days were improved. The modifications with Maillard reaction can improve emulsification, foaming, and gel strength of SPI, and MRPs could be used as a new type of wall material in the production of L. reuteri microcapsules.

siRNAs Targeting Mouse-Specific lncRNA AA388235 Induce Human Tumor Cell Pyroptosis/Apoptosis.

Species-specific lncRNAs significantly determine species-specific functions through various ways, such as epigenetic regulation. However, there has been no study focusing on the role of species-specific lncRNAs in other species yet. Here, we found that siRNAs targeting mouse-specific lncRNA AA388235 could significantly induce death of human tumor cells, although it has no effect on mouse tumor cells and normal human cells. The mechanism studies showed that these siRNAs could activate the response of human tumor cells to exogenous nucleic acids, induce pyroptosis and apoptosis in the presence of GSDME, but induce apoptosis in the absence of GSDME. They also significantly inhibited the growth of human tumor cells in vivo. 17 siRNAs were designed for seven more mouse-specific lncRNAs selected randomly, among which 12 siRNAs targeting five lncRNAs induced death in human tumor cell. Our study not only demonstrates that the siRNAs designed for knocking down mouse-specific lncRNA AA388235 can be potential tumor therapeutic drugs, but also suggests that non-human species-specific lncRNAs are a huge potential library that can be used to design siRNAs for tumor treatment. Large-scale screening based on this is promising.

Analysis of microbial community, physiochemical indices, and volatile compounds of Chinese te-flavor baijiu daqu produced in different seasons.

BACKGROUND: Chinese te-flavor baijiu (CTF), the most famous Chinese baijiu in Jiangxi province, China, is made from a unique daqu. Its characteristic style is closely related to the daqu used for fermentation. However, current studies on the effects of different production seasons on microbial communities, physicochemical indices, and volatile compounds in CTF daqu are very rare. RESULTS: The relationships of microbial communities, physicochemical indices, and volatile compounds in CTF daqu produced in summer (July and August) and autumn (September and October) were studied. The results of Illumina MiSeq sequencing indicated that there was greater bacterial diversity in the CTF daqu-7 (produced in July) and CTF daqu-8 (produced in August) and greater fungal diversity in the CTF daqu-9 (produced in September) and CTF daqu-10 (produced in October). The physicochemical indices of CTF daqu produced in different seasons were significantly different. It was determined that CTF daqu-9 had the highest esterification and liquefaction abilities. A total of 44 volatile compounds, including alcohols, esters, aldehydes, and ketones were identified in CTF daqu produced during different seasons. Among them, CTF daqu-9 had the greatest alcohol content. CONCLUSION: September (early autumn) is the best production period for CTF daqu. The results of the study provide a theoretical basis for the standardized and uniform production of Chinese baijiu. © 2021 Society of Chemical Industry.

The hierarchical assembly of a multi-level DNA ring-based nanostructure in a precise order and its application for screening tumor cells.

DNA nanotechnology can be used to precisely construct nanostructures of different shapes, sizes and surface chemistry, which is appreciated in a variety of areas such as biomaterials, nanodevices, disease diagnosis, imaging, and drug delivery. Enzymatic degradation resistance and cell-targeting capability are indispensable for the applications of DNA nanostructures in biological and biomedical fields, and is challenging to rationally design the desirable nanoscale DNA materials suitable for the clinical translation by the existing assembly methodologies. Herein, we present a simple and efficient method for the hierarchical assembly of a three-level DNA ring-based nanostructure (DNA h-Nanoring) in a precise order, where DNA compositions at the primary level, the second level and the third level are a single DNA ring, two-ring-hybridized duplex and uniform complex macro-cycle, respectively. Most as-assembled DNA h-Nanorings exhibit the regular two-dimensional cycle-shaped structure characterized by atomic force microscopy (AFM). The Nanoring exhibits a significantly enhanced resistance to enzymatic attack, such that it can remain intact in 10% fetal bovine serum (FBS) for 24 h, and even stably exist in the presence of nuclease at a high concentration. More importantly, it is very easy to modify the DNA h-Nanoring with functional moieties (e.g., targeting ligand aptamer) because there are many single-stranded fragments available for further hybridization. By combining with receptor-targeted Sgc8, the nanoring can be used to accomplish the cell imaging and criminate target CEM cells from control cells, demonstrating a potential platform for in vivo tumor imaging and targeted chemotherapeutics delivery.

Nucleic Acids Analysis.

Nucleic acids are natural biopolymers of nucleotides that store, encode, transmit and express genetic information, which play central roles in diverse cellular events and diseases in living things. The analysis of nucleic acids and nucleic acids-based analysis have been widely applied in biological studies, clinical diagnosis, environmental analysis, food safety and forensic analysis. During the past decades, the field of nucleic acids analysis has been rapidly advancing with many technological breakthroughs. In this review, we focus on the methods developed for analyzing nucleic acids, nucleic acids-based analysis, device for nucleic acids analysis, and applications of nucleic acids analysis. The representative strategies for the development of new nucleic acids analysis in this field are summarized, and key advantages and possible limitations are discussed. Finally, a brief perspective on existing challenges and further research development is provided.

Intracellular Nonenzymatic In Situ Growth of Three-Dimensional DNA Nanostructures for Imaging Specific Biomolecules in Living Cells.

Real-time in situ monitoring of low-abundance cancer biomarkers (e.g., miRNAs and proteins) in living cells by nonenzymatic assembly entirely from original DNA probes remains unexplored due to an extremely complex intracellular environment. Herein, a nonenzymatic palindrome-catalyzed DNA assembly (NEPA) technique is developed to execute the in situ imaging of intracellular miRNAs by assembling a three-dimensional nanoscale DNA spherical structure (NS) with low mobility from three free hairpin-type DNAs rather than from DNA intermediates based on the interaction of designed terminal palindromes. Target miRNA was detected down to 1.4 pM, and its family members were distinguished with almost 100% accuracy. The subcellular localization of NS products can be visualized in real time. The NEPA-based sensing strategy is also suitable for the intracellular in situ fluorescence imaging of cancer-related protein receptors, offering valuable insight into developing sensing protocols for understanding the biological function of vital biomolecules in disease pathogenesis and future therapeutic applications.

Facile construction of a ZIF-67/AgCl/Ag heterojunction via chemical etching and surface ion exchange strategy for enhanced visible light driven photocatalysis.

It is of great importance to design and fabricate heterojunction photocatalysts to improve photocatalytic performance. In this work, a novel ZIF-67/AgCl/Ag heterojunction photocatalyst was successfully synthesized by a facile chemical etching, deposition-precipitation, light-induced reduction approach. After chemical etching by a AgNO3 precursor, the crystal size of ZIF-67 decreased remarkably together with the replacement of Co2+ in the framework of ZIF-67 by Ag+ via surface ion exchange. As a result, optical and electrochemical measurements indicated that the separation efficiency of light-induced electrons and holes obviously increased due to the formation of a ZIF-67/AgCl/Ag heterojunction and the surface plasmon resonance of Ag0. Meanwhile, the corresponding kinetic rate constant of ZIF-67/AgCl/Ag was estimated to be 0.1615 min-1, which was 17, 7.76 and 2.67 times as high as that of individual ZIF-67, AgCl and ZIF-67/AgCl, respectively. The ZIF-67/AgCl/Ag photocatalyst also exhibited good stability and reusability in the process of photodegradation. This work demonstrated a high efficiency photocatalyst for providing new sights into the preparation of a highly efficient MOF-based heterojunction photocatalyst and its potential applications in water purification.