Efficacy and Safety of Prolonged Dual Antiplatelet Therapy after Percutaneous Coronary Intervention in Acute Coronary Syndrome Patients.

Objective: It remains controversial whether to extend the course of dual antiplatelet therapy (DAPT) after percutaneous coronary intervention (PCI). We conducted a study to investigate the benefits and risks of applying DAPT for different durations after PCI in acute coronary syndromes (ACS) patients in China. What's more, we explored the efficacy of extended DAPT regimen based on ticagrelor. Methods: This single-center prospective cohort study used data obtained from the PHARM-ACS Patient Registration Database. We included all patients who were discharged between April and December 2018. All patients had at least 18 months of follow-up. Patients were divided into two groups according to the duration of DAPT: a 1-year group and a >1-year group. Potential bias between the two groups was adjusted for by propensity score matching using logistic regression. The primary outcomes were major adverse cardiovascular and cerebrovascular events (MACCE), defined as a composite of death, myocardial infarction, and stroke occurring from 12 months after discharge to follow-up visit. The safety endpoint was any significant bleeding event (BARC ≥ 2). Results: Of 3,205 patients enrolled, 2,201 (68.67%) had DAPT prolonged beyond one year. A total of 2,000 patients were successfully propensity score-matched; patients who received DAPT > 1-year (n = 1000), compared with DAPT = 1-year patients (n = 1000), had a similar risk of MACCE (adjusted HR 0.23, 95% CI 0.05-1.10) and significant bleeding events (adjusted HR 0.63, 95% CI 0.32-1.24). The DAPT > 1-year group had a higher risk of revascularization (adjusted HR 3.36, 95% CI 1.64-6.87). Conclusion: Prolonged DAPT may not be of sufficient benefit to ACS patients within 12-18 months after the index PCI to offset the increased risk of significant bleeding events.

Chaperone Copolymer Assisted G-Quadruplex-Based Signal Amplification Assay for Highly Sensitive Detection of VEGF.

Vascular endothelial growth factor (VEGF) is a critical biomarker in the angiogenesis of several cancers. Nowadays, novel approaches to rapid, sensitive, and reliable VEGF detection are urgently required for early cancer diagnosis. Cationic comb-type copolymer, poly(L-lysine)-graft-dextran (PLL-g-Dex) accelerates DNA hybridization and chain exchange reaction while stabilizing the DNA assembly structure. In this work, we examined the chaperone activity of PLL-g-Dex to assist G-quadruplex-based fluorescent DNA biosensors for sensitive detection of VEGF. This convenient and effective strategy is based on chitosan hydrogel, c-myc, Thioflavin T (ThT), VEGF aptamer, and its partially complementary strand. The results show that chaperone copolymer PLL-g-Dex significantly promotes the accumulation of G-quadruplex and assembles into G-wires, allowing an effective signal amplification. Using this method, the detection limit of VEGF was as low as 23 pM, better than many previous works on aptamer-based VEGF detection. This chaperone copolymer-assisted signal amplification strategy has potential applications in the highly sensitive detection of target proteins, even including viruses.

Signal-On Fluorescence Biosensor for Highly Sensitive Detection of miRNA-21 Based on DNAzyme Assisted Double-Hairpin Molecular Beacon.

Although miRNAs exist in small quantities in the human body, they are closely related to the abnormal expression of genes in diseases such as tumors. Therefore, sensitive detection of miRNAs is very important for the prevention and treatment of various tumors and major diseases. The purpose of this study is to develop a label-free sensing strategy based on the co-action of double-hairpin molecular beacons and deoxyribozymes (DNAzymes) for highly sensitive detection of miRNA-21. The target miRNA-21 promotes the assembly of DNAzyme with a complete catalytic core region. At the presence of Mg2+, DNAzyme cuts a substrate into short chains, which open the double hairpin molecular beacon, and then form G-quadruplexs at both ends, specifically binding more ThT to generate a amplified fluorescent signal. The cut substrate will be replaced by the uncut ones in the next stage, increasing the concentration of reactants, and thus further improving the fluorescence intensity. This DNAzyme assisted double hairpin molecular beacon has a certain degree of discrimination for substances with single base mismatches, and the detection limit of miRNA-21 is 0.13 pM, lower than that of the many other analysis. Further, this detection has good selectivity and sensitivity in serum. Therefore, this strategy provides a simple, fast and low-cost platform for the sensitive detection of miRNA-21, having potential applications in early cancer diagnosis.

Ticagrelor vs. Clopidogrel in Older Patients With Acute Coronary Syndrome Undergoing Percutaneous Coronary Intervention: Insights From a Real-World Registry.

Background and Objectives: It is unclear whether more potent P2Y12 inhibitors are of benefit to older patients who are at high risk for both ischemia and bleeding. We conducted an observational study to compare the clinical outcomes of clopidogrel and ticagrelor uses in older patients with an acute coronary syndrome (ACS). Methods: Older patients (aged ≥65 years) with ACS who underwent percutaneous coronary intervention (PCI) were divided into clopidogrel-treated and ticagrelor-treated groups. The primary observational endpoint was the occurrence of net adverse clinical and cerebral events (NACCEs) during a 12-month period, which is defined as the composite endpoint of all-cause death, myocardial infarction (MI), stroke, stent thrombosis, urgent coronary revascularization, and clinically significant bleeding. The secondary endpoints were clinically significant bleeding and major adverse clinical and cerebral events (MACCEs). Results: This study included a total of 2,611 patients. Of them, 1,636 received clopidogrel and 975 received ticagrelor. Between patients receiving clopidogrel and those receiving ticagrelor, no significant differences were noted in NACCE (8.4 vs. 9.7%, respectively; adjusted hazard ratio [HR], 0.86; 95% confidence interval [CI], 0.66-1.12) or MACCE (7.1 vs. 7.0%, respectively; adjusted HR, 1.13; 95% CI, 0.83-1.55) during the 12-month follow-up period. In contrast, the occurrence of clinically significant bleeding was significantly less in clopidogrel-treated patients compared with that in ticagrelor-treated patients (27, 1.7%, vs. 31, 3.2%, respectively; adjusted HR, 0.42; 95% CI, 0.25-0.69). Stratified analyses revealed no significant association between age (≥75 years vs. <75 years) and treatment condition in terms of primary or secondary endpoints. Conclusion: This study showed that clopidogrel and ticagrelor had comparable net clinical benefits in patients with ACS aged ≥65 years. Additionally, clopidogrel was associated with a significantly lower risk of major bleeding than ticagrelor without an increase in ischemic risk. These findings suggest that clopidogrel is an effective alternative to the more potent P2Y12 inhibitor ticagrelor in older patients.

Metformin and the risk of neurodegenerative diseases in patients with diabetes: A meta-analysis of population-based cohort studies.

AIMS: The association between metformin use and neurodegenerative disease (ND) onset remains controversial. In this systematic review and meta-analysis, we aimed to determine the relationship between metformin use and ND risk based on data from population-based cohort studies. METHODS: Articles were systematically searched in PubMed, EMBASE and Cochrane Library databases. Pooled relative risks (RRs) with 95% CIs were obtained using a random-effects model. Subgroup analyses, sensitivity analyses and meta-regression were performed to identify the sources of heterogeneity and strengthen the results. RESULTS: Twelve population-based cohort studies involving 194,792 participants (94,462 metformin users and 100,330 metformin non-users) were eligible for inclusion in this meta-analysis. The pooled RR of NDs reached 0.77 (95% CI 0.67-0.88) when comparing metformin users with non-users. The effects were more prominent in long-term metformin users (≥4 years) (RR 0.29, 95% CI 0.13-0.44) and studies from Asian countries (RR 0.69, 95% CI 0.64-0.74). The effect estimates were stable when stratified by subtypes of NDs, study designs, and control definitions (p for interaction >0.05). Meta-regression did not identify the coefficients as the sources of heterogeneity (all p > 0.05). CONCLUSIONS: This systematic review and meta-analysis found that metformin use, especially long-term use, was associated with lower ND risk. However, because there was substantial heterogeneity among studies, high-quality randomized controlled trials are still needed to confirm this finding.

Clopidogrel versus Ticagrelor in CYP2C19 Loss-of-Function Allele Noncarriers: A Real-World Study in China.

OBJECTIVE: This article compares the clinical outcomes of clopidogrel and ticagrelor in patients with acute coronary syndrome (ACS) without cytochrome P450 (CYP)2C19 loss-of-function (LOF) alleles and investigates whether clopidogrel could be an alternative P2Y12 inhibitor without increasing the risk of ischemic events. METHODS: Patients were divided into the clopidogrel-treated group and the ticagrelor-treated group. Inverse probability of treatment weighting (IPTW) calculated by propensity scores was used to adjust confounding covariates. The primary outcome was major adverse cardiovascular or cerebrovascular events (MACCEs) within 12 months. The secondary outcomes were MACCEs plus unstable angina, and clinically significant bleeding events. RESULTS: Finally, 2,199 patients were included. Of them, 1,606 were treated with clopidogrel, and 593 were treated with ticagrelor. The mean age of the original cohort was 59.92 ± 9.81 years. During the 12-month follow-up period, MACCEs occurred in 89 patients (4.0%). No significant differences were observed in MACCEs (IPTW-adjusted hazard ratio [HR], 0.87; 95% confidence interval [CI], 0.65-1.18), MACCEs plus unstable angina (IPTW-adjusted HR, 1.20; 95% CI, 0.91-1.59), or clinically significant bleeding events (IPTW-adjusted HR, 0.81; 95% CI, 0.53-1.23) between the clopidogrel- and ticagrelor-treated groups. CONCLUSION: In patients with ACS without CYP2C19 LOF alleles, clopidogrel was not associated with a higher risk of MACCEs when compared with ticagrelor. The main findings of this study support use of clopidogrel in CYP2C19 LOF noncarriers as an alternative P2Y12 inhibitor, which may reduce medical expenses and adverse reactions caused by more potent P2Y12 inhibitors in these patients.

A DNA Electrochemical Sensor via Terminal Protection of Small-Molecule-Linked DNA for Highly Sensitive Protein Detection.

The qualitative and quantitative determination of marker protein is of great significance in the life sciences and in medicine. Here, we developed an electrochemical DNA biosensor for protein detection based on DNA self-assembly and the terminal protecting effects of small-molecule-linked DNA. This strategy is demonstrated using the small molecule biotin and its receptor protein streptavidin (SA). We immobilized DNA with a designed structure and sequence on the surface of the gold electrode, and we named it M1-Biotin DNA. M1-Biotin DNA selectively combines with SA to generate M1-Biotin-SA DNA and protects M1-Biotin DNA from digestion by EXO III; therefore, M1-Biotin DNA remains intact on the electrode surface. M1-Biotin-SA DNA was modified with methylene blue (MB); the MB reporter molecule is located near the surface of the gold electrode, which generates a substantial electrochemical signal during the detection of SA. Through this strategy, we can exploit the presence or absence of an electrochemical signal to provide qualitative target protein determination as well as the strength of the electrochemical signal to quantitatively analyze the target protein concentration. This strategy has been proven to be used for the quantitative analysis of the interaction between biotin and streptavidin (SA). Under optimal conditions, the detection limit of the proposed biosensor is as low as 18.8 pM, and the linear range is from 0.5 nM to 5 µM, showing high sensitivity. The detection ability of this DNA biosensor in complex serum samples has also been studied. At the same time, we detected the folate receptor (FR) to confirm that this strategy can be used to detect other proteins. Therefore, this electrochemical DNA biosensor provides a sensitive, low-cost, and fast target protein detection platform, which may provide a reliable and powerful tool for early disease diagnosis.

MiRNA Detection Using a Rolling Circle Amplification and RNA-Cutting Allosteric Deoxyribozyme Dual Signal Amplification Strategy.

A microRNA (miRNA) detection platform composed of a rolling circle amplification (RCA) system and an allosteric deoxyribozyme system is proposed, which can detect miRNA-21 rapidly and efficiently. Padlock probe hybridization with the target miRNA is achieved through complementary base pairing and the padlock probe forms a closed circular template under the action of ligase; this circular template results in RCA. In the presence of DNA polymerase, RCA proceeds and a long chain with numerous repeating units is formed. In the presence of single-stranded DNA (H1 and H2), multi-component nucleic acid enzymes (MNAzymes) are formed that have the ability to cleave substrates. Finally, substrates containing fluorescent and quenching groups and magnesium ions are added to the system to activate the MNAzyme and the substrate cleavage reaction, thus achieving fluorescence intensity amplification. The RCA-MNAzyme system has dual signal amplification and presents a sensing platform that demonstrates broad prospects in the analysis and detection of nucleic acids.

Personalized Antiplatelet Therapy Based on CYP2C19 Genotypes in Chinese ACS Patients Undergoing PCI: A Randomized Controlled Trial.

Background: The clinical benefits of cytochrome P450 (CYP) 2C19 genotype-guided antiplatelet therapy in Asians remain unclear. In this study, we aimed to investigate the clinical outcomes of pharmacogenomic antiplatelet therapy in Chinese patients. Methods: Patients with acute coronary syndrome planning to undergo percutaneous coronary intervention were eligible for this study and were randomly divided into a genotype-guided treatment (GT) group and routine treatment (RT) group, with a ratio of 2:1. Patients in the GT group underwent CYP2C19 genotyping (*2 and *3 alleles), and the results were considered in selecting P2Y12 receptor inhibitors. Patients in the RT group were treated with P2Y12 receptor inhibitors according to their clinical characteristics. The primary endpoint was a composite of major adverse cardiovascular or cerebrovascular events (MACCE). The secondary endpoint was significant bleeding events. Results: Finally, 301 patients were enrolled; 75.1% were men and the mean age was 59.7 ± 9.8 years. In total, 281 patients completed the follow-up procedure. The primary endpoint occurred in 16 patients, 6 patients in the GT group and 10 in the RT group. The GT group showed lower MACCE rates than the RT group (6/189 vs. 10/92, 3.2 vs. 10.9%, hazard ratio: 0.281, 95% confidence interval: 0.102-0.773, P = 0.009). There was no statistically difference in significant bleeding events between the GT and RT groups (4.2 vs. 3.3%, hazard ratio: 1.315, 95% confidence interval: 0.349-4.956, P = 0.685). Conclusion: Personalized antiplatelet therapy that is based on CYP2C19 genotypes could decrease MACCE within a 12-month period in Chinese patients with acute coronary syndrome undergoing percutaneous coronary intervention. Clinical Trial Registration: http://www.chictr.org.cn, identifier: ChiCTR2000034352.

Tryptanthrin Regulates Vascular Smooth Muscle Cell Phenotypic Switching in Atherosclerosis by AMP-Activated Protein Kinase/Acetyl-CoA Carboxylase Signaling Pathway.

ABSTRACT: Atherosclerosis (AS) is one of the most severe cardiovascular diseases involved in the phenotypic switching of vascular smooth muscle cells (VSMCs). Tryptanthrin is a natural product with broad biological activities. However, the effect of tryptanthrin on atherosclerotic progression is unclear. The aim of this study was to determine the role of tryptanthrin in AS and explore the potential mechanism. In vitro, primary VSMCs were stimulated with platelet-derived growth factor-BB (PDGF) to induce cell dedifferentiation. Treatment with tryptanthrin (5 µM or 10 µM) suppressed the proliferation and recovered the contractility of VSMCs in the presence of PDGF. The contractile proteins (α-smooth muscle actin, calponin, and SM22α) were increased, and the synthetic protein vimentin was decreased by tryptanthrin in PDGF-induced VSMCs. ApoE-/- mice fed with high-fat diet were used as an in vivo model of AS. Similarly, gavage administration of tryptanthrin (50 mg/kg or 100 mg/kg) attenuated VSMC phenotypic changes from a contractile to a synthetic state in aortic tissues of AS mice. The serum lipid level, atherosclerotic plaque formation, and arterial intimal hyperplasia were attenuated by tryptanthrin. Furthermore, tryptanthrin increased the expression levels of phosphorylated AMP-activated protein kinase (AMPK) and acetyl-CoA carboxylase (ACC) both in vitro and in vivo. Administration of compound C, an AMPK inhibitor, reversed the inhibitory effect of tryptanthrin on VSMC dedifferentiation in vitro. Thus, we demonstrate that tryptanthrin protects against AS progression through the inhibition of VSMC switching from a contractile to a pathological synthetic phenotype by the activation of AMPK/ACC pathway. It provides novel insights into AS prevention and treatment.

Convallatoxin Promotes M2 Macrophage Polarization to Attenuate Atherosclerosis Through PPARγ-Integrin αvß5 Signaling Pathway.

INTRODUCTION: As the primary immune cells, macrophages play a key role in atherosclerotic progression. M2 macrophage polarization has been reported to promote tissue repair and attenuate plaque formation upon the expression of anti-inflammatory factors. Convallatoxin (CNT) is a natural cardiac glycoside with anti-inflammatory pharmacological properties. However, whether CNT protects against atherosclerosis (AS) and underlying mechanisms is unknown. This work was designed to explore the potential effects of CNT on atherosclerosis. METHODS: In this study, Apolipoprotein E deficiency (ApoE-/-) mice fed with high-fat diet were established, and CNT (50 or 100 µg/kg) were intragastrically administrated for 12 weeks every day. In vitro, RAW264.7 macrophages stimulated with ox-LDL were treated with CNT (50 or 100 nM) for 24 h. The specific PPARγ antagonist, GW9662, was used to block the PPARγ signaling pathway in vitro. Then, the atherosclerotic lesions, macrophage polarization markers, inflammatory cytokines and PPARγ signaling pathway were examined in further examinations. RESULTS: Our results showed that the atherosclerotic lesions were reduced by CNT, as demonstrated by the downregulation of serum lipid level and aortic plaque area in AS mice. Furthermore, we found that CNT treatment promoted the expression of M2 macrophage markers (Arg1, Mrc1, Retnla and Chi3l3), and decreased the levels of pro-inflammatory cytokines (IL-6 and TNF-α), accompanied by the increase of anti-inflammatory factor (IL-10) in aortic vessels of AS mice. In ox-LDL-induced RAW264.7 cells, CNT administration also facilitated macrophages polarizing towards M2 subtype and inhibited inflammatory responses. Furthermore, both the in vivo and in vitro experiments showed CNT could increase the expression of PPARγ, Integrin αv and Integrin ß5, and GW9662 could block CNT-induced M2 macrophage polarization. CONCLUSION: Taken together, these data suggest that CNT may promote M2 macrophage polarization to exert an anti-atherosclerotic effect, partially through activating PPARγ-Integrin αvß5 signaling pathway.

DNAzyme-Based Target-Triggered Rolling-Circle Amplification for High Sensitivity Detection of microRNAs.

MicroRNAs regulate and control the growth and development of cells and can play the role of oncogenes and tumor suppressor genes, which are involved in the occurrence and development of cancers. In this study, DNA fragments obtained by target-induced rolling-circle amplification were constructed to complement with self-cleaving deoxyribozyme (DNAzyme) and release fluorescence biomolecules. This sensing approach can affect multiple signal amplification permitting fluorescence detection of microRNAs at the pmol L-1 level hence affording a simple, highly sensitive, and selective low cost detection platform.

Impact of Implementing CYP2C19 Genotype-Guided Antiplatelet Therapy on P2Y12 Inhibitor Selection and Clinical Outcomes in Acute Coronary Syndrome Patients After Percutaneous Coronary Intervention: A Real-World Study in China.

Background: CYP2C19 loss-of-function (LOF) alleles reduce the effectiveness of clopidogrel in patients undergoing percutaneous coronary intervention for acute coronary syndrome. However, the clinical impact of implementing CYP2C19 gene-guided pharmacotherapy is unclear, especially among the Chinese population. The purpose of this study was to evaluate P2Y12 receptor inhibitor selection and clinical outcomes upon implementation of CYP2C19 genotype-guided pharmacotherapy in current clinical practice. Methods: This was a single-center observational cohort study. Adult percutaneous coronary intervention patients who received CYP2C19 genetic testing (*2, *3, *17 alleles) were included. Ticagrelor was recommended for patients with a LOF allele. Factors related to P2Y12 inhibitor selection were determined by logistic regression. The primary endpoint was major cardiac or cerebrovascular adverse events (MACCE) within 12 months. MACCE and clinically significant bleeding events (BARC ≥2) in the LOF-clopidogrel group, non-LOF-clopidogrel group, and non-LOF-ticagrelor group were compared with those in the LOF-ticagrelor group. The inverse probability of treatment weighting (IPTW) was adjusted in a Cox regression analysis to eliminate confounding factors. Results: Among 1,361 patients, 826 (60.7%) had a LOF allele. Patients with a LOF allele were more likely to be prescribed ticagrelor (multivariate-adjusted OR 1.349; 95% CI 1.040 to 1.751; p = 0.024). The MACCE rate was higher in the LOF-clopidogrel group than in the LOF-ticagrelor group (7.8 vs. 4.0%; log-rank p = 0.029; IPTW-adjusted HR 2.138; 95% CI 1.300-3.515). Compared with the LOF-ticagrelor group, the non-LOF-clopidogrel group showed no significant difference in MACCE rate (5.8 vs. 4.0%; log-rank p = 0.272; IPTW-adjusted HR 1.531; 95% CI 0.864-2.714). Among the patients treated with ticagrelor, there was no significant difference in the MACCE rate between the LOF group and non-LOF group (4.3 vs. 4.0%; log-rank p = 0.846; IPTW-adjusted HR 1.184; 95% CI 0.582-2.410). There was no significant difference in the incidence of clinically significant bleeding events among the four groups. Conclusion: This study confirms that efficiently returned CYP2C19 genotype results did partially guide cardiologists to prescribe ticagrelor for patients with a LOF allele, and that clopidogrel had a higher risk of MACCE than ticagrelor in these patients, which provides support for the implementation of CYP2C19 gene-guided antiplatelet therapy in clinical practice.

Detection and identification of the oxidizing species generated from the physiologically important Fenton-like reaction of iron(II)-citrate with hydrogen peroxide.

The Fenton-like reaction of iron(II)-citrate with hydrogen peroxide is physiologically important because it is associated with the oxidative stress and pathological processes induced by the redox-active iron pool in vivo. However, the oxidizing species generated from this reaction at neutral pH has not been convincingly identified because two extremely unstable and hard-to-differentiate species, the hydroxyl radical (•OH) and iron(IV) (ferryl) species, can be produced. Identifying this species is essential for understanding the reaction mechanism. Although there were few data that reported the detection of •OH from this reaction by using the EPR and fluorescence techniques, most of these data were obtained without the necessary assessment with a •OH scavenger. Furthermore, these two techniques may not be able to differentiate the •OH and iron(IV) species. Thus, these reported data cannot lead to a convincing conclusion that the •OH, not the iron(IV) species, was generated. Therefore, in the study reported herein, we carried out systematic investigations first by using the EPR and fluorescence techniques combined with a •OH scavenger to detect the oxidizing species generated from this Fenton-like reaction. Then we utilized NMR spectroscopy and for the first time obtained convincing evidence to demonstrate that this oxidizing species is the •OH rather than iron(IV) species. We also determined the second-order rate constant of the reaction, 3.6 × 103 M-1s-1 (pH7.0, 25 °C), by using the stopped-flow spectrophotometry. On the basis of these findings, a scheme is proposed for the mechanism of this physiologically important Fenton-like reaction.

Novel detection platform for insulin based on dual-cycle signal amplification by Exonuclease III.

A novel detection platform based on Exonuclease III dual-cycle signal amplification with graphene oxide as quenching agent and DNA labelling as recognition element has been developed for the fluorometric determination of insulin. Specific DNA sequences were cut by Exo III to control the fluorescence recovery of the system. Fluorescence intensity analysis was carried out by fluorescence spectrophotometer to obtain the fluorescence intensity corresponding to different concentrations of insulin. When insulin is added to the system, insulin binds to the adaptor and the fluorescence is quenched, whereas in the absence of insulin the fluorescence is restored. The sensor platform achieved multiple signal amplification affording rapid and sensitive detection of insulin with a detection range of 0.048-2.15 U/ml. The methodology is rapid, sensitive, of low cost and convenient to perform and has potential for routine screening of insulin in blood, and also has prospects for the detection of other proteins and biomolecules.

Fluorescent DNA Biosensor for Single-Base Mismatch Detection Assisted by Cationic Comb-Type Copolymer.

Simple and rapid detection of DNA single base mismatch or point mutation is of great significance for the diagnosis, treatment, and detection of single nucleotide polymorphism (SNP) in genetic diseases. Homogeneous mutation assays with fast hybridization kinetics and amplified discrimination signals facilitate the automatic detection. Herein we report a quick and cost-effective assay for SNP analysis with a fluorescent single-labeled DNA probe. This convenient strategy is based on the efficient quenching effect and the preferential binding of graphene oxide (GO) to ssDNA over dsDNA. Further, a cationic comb-type copolymer (CCC), poly(l-lysine)-graft-dextran (PLL-g-Dex), significantly accelerates DNA hybridization and strand-exchange reaction, amplifying the effective distinction of the kinetic barrier between a perfect matched DNA and a mismatched DNA. Moreover, in vitro experiments indicate that RAW 264.7 cells cultured on PLL-g-Dex exhibits excellent survival and proliferation ability, which makes this mismatch detection strategy highly sensitive and practical.

A Label-Free Fluorescent DNA Machine for Sensitive Cyclic Amplification Detection of ATP.

In this study, a target recycled amplification, background signal suppression, label-free fluorescent, enzyme-free deoxyribonucleic acid (DNA) machine was developed for the detection of adenosine triphosphate (ATP) in human urine. ATP and DNA fuel strands (FS) were found to trigger the operation of the DNA machine and lead to the cyclic multiplexing of ATP and the release of single stranded (SS) DNA. Double-stranded DNA (dsDNA) was formed on graphene oxide (GO) from the combination of SS DNA and complementary strands (CS'). These double strands then detached from the surface of the GO and in the process interacted with PicoGreen dye resulting in amplifying fluorescence intensity. The results revealed that the detection range of the DNA machine is from 100 to 600 nM (R² = 0.99108) with a limit of detection (LOD) of 127.9 pM. A DNA machine circuit and AND-NOT-AND-OR logic gates were successfully constructed, and the strategy was used to detect ATP in human urine. With the advantage of target recycling amplification and GO suppressing background signal without fluorescent label and enzyme, this developed strategy has great potential for sensitive detection of different proteins and small molecules.

Chaperone Copolymer-Assisted Aptamer-Patterned DNA Hydrogels for Triggering Spatiotemporal Release of Protein.

In this paper, a DNA hydrogel with low DNA concentration, short sticky end, and good mechanical strength was simply prepared via one-pot self-assembly from two kinds of DNA building block (X- and L-shaped DNA units) chaperoned by a cationic comb-type copolymer (CCC). The gelling process was completed under physiological conditions within 1 min, and the reversible sol-gel phase transition was achieved at room temperature through the continuous addition of CCC and an anionic polymer poly(sodium vinylsulfonate). Moreover, aptamer was successfully patterned into the hydrogel system via click chemistry. Upon the addition of complementary sequences (CSs) of aptamer, the aptamer was hybridized with CSs, leading to the fast dissociation of protein from aptamer with an adjustable release rate in specific regions at prospective times. The hydrogel with excellent cytocompatibility was successfully applied to human serum, a complex matrix. The aptamer-patterned DNA hydrogel is a potential candidate for controlled protein delivery.