BCL6 confers resistance to HDAC inhibitors in DLBCL.

Diffuse large B-cell lymphoma (DLBCL) is an aggressive non-Hodgkin lymphoma with limited response to chemotherapy. Histone acetylation is reduced in DLBCL. Chidamide, a histone deacetylase inhibitor, shows promise in lymphomas but needs further investigation for DLBCL. Our study indicated that chidamide effectively suppresses DLBCL both in vitro and in vivo. High-throughput RNA sequencing analysis provided comprehensive evidence that chidamide markedly influences crucial signaling pathways in DLBCL, including the MAPK, MYC and p53 pathway. Additionally, we observed substantial variability in the sensitivity of DLBCL cells to chidamide, and identified that elevated expression of BCL6 might confer resistance to chidamide in DLBCL. Moreover, our investigations revealed that BCL6 inhibited chidamide-induced histone acetylation by recruiting histone deacetylase (HDACs), leading to drug resistance in DLBCL cells. Furthermore, we found that lenalidomide targeted BCL6 degradation through the ubiquitination pathway and restore the sensitivity of drug-resistant DLBCL to chidamide. Collectively, these findings provided valuable insights into the global impact of chidamide on DLBCL and highlight the potential of targeting HDACs as a therapeutic strategy for DLBCL. Identifying BCL6 as a biomarker for predicting the response to chidamide and the combination therapy with BCL6 inhibition has the potential to lead to more personalized and effective treatments for DLBCL patients.

Design of U-shaped peptides with long-lasting antifouling efficacy: Toward a feasible electrochemical aptasensor for robust detection in human serum.

BACKGROUND: Developing biosensors with antifouling properties is essential for accurately detecting low-concentration biomarkers in complex biological matrix, which is imperative for effective disease diagnosis and treatment. Herein, an antifouling electrochemical aptasensor qualifying for probing targets in human serum was explored based on newly-devised peptides that could form inverted U-shaped structures with long-term stability. RESULTS: The inverted U-shaped peptides (U-Pep) with two terminals of thiol groups grafted onto the Au-modified electrode showcase superior antifouling properties in terms of high stability against enzymatic hydrolysis and long acting against biofouling in actual biofluids. The construction of the outlined antifouling electrochemical aptasensor just involved the fabrication of Au-deposited poly(3,4 ethylenedioxythiophene) (Au/PEDOT) modified electrode, followed by one-step co-incubation in the peptides and the aptamer probes with the Au/PEDOT electrode. Taking a typical biomarker of alpha-fetoprotein (AFP) for detection, this elegant antifouling aptasenor demonstrated a nice response for probing the target AFP with a low detection limit of 0.27 pg/mL and a wide linear scope of 1.0 pg/mL to 1.0 µg/mL, and furthermore qualified for assaying of AFP in human serum samples with satisfactory accuracy and feasibility. SIGNIFICANCE: This engineering strategy of U-Pep with long-lasting antifouling efficacy opens a new horizon for high-performance antifouling biosensors suitable for detection in complex bifluids, and it could spark more inspiration for a follow-up exploration of other featured antifouling biomaterials.

Heat shock protein 90 and prolyl hydroxylase 2 co-regulate hypoxia-inducible factor-1α expression in porcine small intestinal epithelial cells under heat stress.

Heat stress (HS) poses a substantial threat to animal growth and development, resulting in declining performance and economic losses. The intestinal system is susceptible to HS and undergoes intestinal hyperthermia and pathological hypoxia. Hypoxia-inducible factor-1α (HIF-1α), a key player in cellular hypoxic adaptation, is influenced by prolyl-4-hydroxylase 2 (PHD2) and heat shock protein 90 (HSP90). However, the comprehensive regulation of HIF-1α in the HS intestine remains unclear. This study aims to explore the impact of HS on pig intestinal mucosa and the regulatory mechanism of HIF-1α. Twenty-four Congjiang Xiang pigs were divided into the control and five HS-treated groups (6, 12, 24, 48, and 72 h). Ambient temperature and humidity were maintained in a thermally-neutral state (temperature-humidity index (THI) < 74) in the control group, whereas the HS group experienced moderate HS (78 < THI <84). Histological examination revealed villus exfoliation after 12 h of HS in the duodenum, jejunum, and ileum, with increasing damage as HS duration extended. The villus height to crypt depth ratio (V/C) decreased and goblet cell number increased with prolonged HS. Quantitative real-time PCR, Western blot, and immunohistochemistry analysis indicated increased expression of HIF-1α and HSP90 in the small intestine with prolonged HS, whereas PHD2 expression decreased. Further investigation in IPEC-J2 cells subjected to HS revealed that overexpressing PHD2 increased PHD2 mRNA and protein expression, while it decreases HIF-1α. Conversely, interfering with HSP90 expression substantially decreased both HSP90 and HIF-1α mRNA and protein levels. These results suggest that HS induces intestinal hypoxia with concomitant small intestinal mucosal damage. The expression of HIF-1α in HS-treated intestinal epithelial cells may be co-regulated by HSP90 and PHD2 and is possibly linked to intestinal hyperthermia and hypoxia.

Atherosclerosis is associated with plasma Aß levels in non-hypertension patients.

BACKGROUND: Growing evidence indicated that to develop of atherosclerosis observed more often by people with Alzheimer's disease (AD), but the underlying mechanism is not fully clarified. Considering that amyloid-ß (Aß) deposition in the brain is the key pathophysiology of AD and plasma Aß is closely relate to Aß deposition in the brain, in the present study, we investigated the relationships between atherosclerosis and plasma Aß levels. METHODS: This was a population based cross-sectional study. Patients with high risk of atherosclerosis from Qubao Village, Xi'an were underwent carotid ultrasound for assessment of atherosclerosis. Venous blood was collected on empty stomach in the morning and plasma Aß1-40 and Aß1-42 levels were measured using ELISA. Multivariate logistic regression analysis was performed to investigate the relationships between carotid atherosclerosis (CAS) and plasma Aß levels. RESULTS: Among 344 patients with high risk of atherosclerosis, 251(73.0%) had CAS. In the univariate analysis, the plasma Aß levels had no significant differences between CAS group and non-CAS group (Aß1-40: 53.07 ± 9.24 pg/ml vs. 51.67 ± 9.11pg/ml, p = 0.211; Aß1-42: 40.10 ± 5.57 pg/ml vs. 40.70 pg/ml ± 6.37pg/ml, p = 0.285). Multivariate logistic analysis showed that plasma Aß levels were not associated with CAS (Aß1-40: OR = 1.019, 95%CI: 0.985-1.054, p = 0.270;Aß1-42: OR = 1.028, 95%CI: 0.980-1.079, p = 0.256) in the total study population. After stratified by hypertension, CAS was associated with plasma Aß1-40 positively (OR = 1.063, 95%CI: 1.007-1.122, p = 0.028) in the non-hypertension group, but not in hypertensive group. When the plasma Aß concentrations were classified into four groups according to its quartile, the highest level of plasma Aß1-40 group was associated with CAS significantly (OR = 4.465, 95%CI: 1.024-19.474, p = 0.046). CONCLUSION: Among patients with high risk of atherosclerosis, CAS was associated with higher plasma Aß1-40 level in non-hypertension group, but not in hypertension group. These indicated that atherosclerosis is associated with plasma Aß level, but the relationship may be confounded by hypertension.

Intelligent Cell Profiling and Precision Release: Multimolecular Marker-Activated Transmembrane DNA Computing Nanosystem.

Accurate classification of tumor cells is of importance for cancer diagnosis and further therapy. In this study, we develop multimolecular marker-activated transmembrane DNA computing systems (MTD). Employing the cell membrane as a native gate, the MTD system enables direct signal output following simple spatial events of "transmembrane" and "in-cell target encounter", bypassing the need of multistep signal conversion. The MTD system comprises two intelligent nanorobots capable of independently sensing three molecular markers (MUC1, EpCAM, and miR-21), resulting in comprehensive analysis. Our AND-AND logic-gated system (MTDAND-AND) demonstrates exceptional specificity, allowing targeted release of drug-DNA specifically in MCF-7 cells. Furthermore, the transformed OR-AND logic-gated system (MTDOR-AND) exhibits broader adaptability, facilitating the release of drug-DNA in three positive cancer cell lines (MCF-7, HeLa, and HepG2). Importantly, MTDAND-AND and MTDOR-AND, while possessing distinct personalized therapeutic potential, share the ability of outputting three imaging signals without any intermediate conversion steps. This feature ensures precise classification cross diverse cells (MCF-7, HeLa, HepG2, and MCF-10A), even in mixed populations. This study provides a straightforward yet effective solution to augment the versatility and precision of DNA computing systems, advancing their potential applications in biomedical diagnostic and therapeutic research.

Discovery of gefitinib-1,2,3-triazole derivatives against lung cancer via inducing apoptosis and inhibiting the colony formation.

A series of 20 novel gefitinib derivatives incorporating the 1,2,3-triazole moiety were designed and synthesized. The synthesized compounds were evaluated for their potential anticancer activity against EGFR wild-type human non-small cell lung cancer cells (NCI-H1299, A549) and human lung adenocarcinoma cells (NCI-H1437) as non-small cell lung cancer. In comparison to gefitinib, Initial biological assessments revealed that several compounds exhibited potent anti-proliferative activity against these cancer cell lines. Notably, compounds 7a and 7j demonstrated the most pronounced effects, with an IC50 value of 3.94 ± 0.17 µmol L-1 (NCI-H1299), 3.16 ± 0.11 µmol L-1 (A549), and 1.83 ± 0.13 µmol L-1 (NCI-H1437) for 7a, and an IC50 value of 3.84 ± 0.22 µmol L-1 (NCI-H1299), 3.86 ± 0.38 µmol L-1 (A549), and 1.69 ± 0.25 µmol L-1 (NCI-H1437) for 7j. These two compounds could inhibit the colony formation and migration ability of H1299 cells, and induce apoptosis in H1299 cells. Acute toxicity experiments on mice demonstrated that compound 7a exhibited low toxicity in mice. Based on these results, it is proposed that 7a and 7j could potentially be developed as novel drugs for the treatment of lung cancer.

Enhanced split-type photoelectrochemical aptasensor incorporating a robust antifouling coating derived from four-armed polyethylene glycol.

Antifouling biosensors capable of preventing protein nonspecific adhesion in real human bodily fluids are highly sought-after for precise disease diagnosis and treatment. In this context, an enhanced split-type photoelectrochemical (PEC) aptasensor was developed incorporating a four-armed polyethylene glycol (4A-PEG) to construct a robust antifouling coating, enabling accurate and sensitive bioanalysis. The split-type PEC system involved the photoelectrode and the biocathode, effectively separating signal converter with biorecogniton events. Specifically, the TiO2 electrode underwent sequential modification with ZnIn2S4 (ZIS) and polydopamine (PDA) to form the PDA/ZIS/TiO2 photoelectrode. The cathode substrate was synthesized as a hybrid of N-doped graphene loaded with Pt nanoparticles (NG-Pt), and subsequently modified with 4A-PEG to establish a robust antifouling coating. Following the anchoring of probe DNA (pDNA) on the 4A-PEG-grafted antifouling coating, the biocathode for model target of cancer antigen 125 (CA125) was obtained. Leveraging pronounced photocurrent output of the photoelectrode and commendable antifouling characteristics of the biocathode, the split-type PEC aptasensor showcased exceptional detection performances with high sensitivity, good selectivity, antifouling ability, and potential feasibility.

Click Conjugation of Zwitterionic Peptide with DNA Strand: An Efficient Antifouling Strategy for Versatile Photoelectrochemical Aptasensor.

Advanced antifouling biosensors have garnered considerable attention for their potential for precise and sensitive analysis in complex human bodily fluids. Herein, a pioneering approach was utilized to establish a robust and versatile photoelectrochemical aptasensor by conjugating a zwitterionic peptide with a DNA strand. Specifically, the branched zwitterionic peptide (BZP) was efficiently linked to complementary DNA (cDNA) through a click reaction, forming the BZP-cDNA conjugate. This intriguing conjugate exploited the BZP domain to create an antifouling biointerface, while the cDNA component facilitated subsequent hybridization with probe DNA (pDNA). To advance the development of the aptasensor, an upgraded PDA/HOF-101/ZnO ternary photoelectrode was designed as the signal converter for the modification of the BZP-cDNA conjugate, while a bipyridinium (MCEPy) molecule with strong electron-withdrawing properties was labeled at the front end of the pDNA to form the pDNA-MCEPy signal probe. Targeting the model of mucin-1, a remarkable enhancement in the photocurrent signal was achieved through exonuclease-I-aided target recycling. Such an engineered zwitterionic peptide-DNA conjugate surpasses the limitations imposed by conventional peptide-based sensing modes, exhibiting unique advantages such as versatility in design and capability for signal amplification.

Robust Electrochemical Biosensors Based on Antifouling Peptide Nanoparticles for Protein Quantification in Complex Biofluids.

Peptides with distinct physiochemical properties and biocompatibility hold significant promise across diverse domains including antifouling biosensors. However, the stability of natural antifouling peptides in physiological conditions poses significant challenges to their viability for sustained practical applications. Herein, a unique antifouling peptide FFFGGGEKEKEKEK was designed and self-assembled to form peptide nanoparticles (PNPs), which possessed enhanced stability against enzymatic hydrolysis in biological fluids. The PNP-coated interfaces exhibited superior stability and antifouling properties in preventing adsorption of nonspecific materials, such as proteins and cells in biological samples. Moreover, a highly sensitive and ultralow fouling electrochemical biosensor was developed through the immobilization of the PNPs and specific aptamers onto the polyaniline nanowire-modified electrode, achieving the biomarker carcinoembryonic antigen detection in complex biofluids with reliable accuracy. This research not only addresses the challenge of the poor proteolytic resistance observed in natural peptides but also introduces a universal strategy for constructing ultralow fouling sensing devices.

Highly Light-Harvesting MOF-on-MOF Heterostructure: Cascading Functionality to Flexible Photogating of Organic Photoelectrochemical Transistor and Bienzyme Cascade Detection.

Recently, organic photoelectrochemical transistor (OPECT) bioanalysis has become a prominent technique for the high-performance detection of biomolecules. However, as a sensitive index of the OPECT, the dynamic regulation transconductance (gm) is still severely deficient. Herein, this work reports a new photosensitive metal-organic framework (MOF-on-MOF) heterostructure for the effective modulation of maximum gm and natural bienzyme interfacing toward choline detection. Specifically, the bidentate ligand MOF (b-MOF) was assembled onto the UiO-66 MOF (u-MOF) by a modular assembly method, which could facilitate the charge separation and generate enhanced photocurrents and offer a biophilic environment for the immobilization of choline oxidase (ChOx) and horseradish peroxidase (HRP) through hydrogen-bonded bridges. The transconductance of the OPECT could be flexibly altered by increased light intensity to maximal value at zero gate bias, and sensitive choline detection was achieved with a detection limit of 0.2 µM. This work reveals the potential of MOF-on-MOF heterostructures for futuristic optobioelectronics.

Principle and Application of Ultraviolet Crosslinking Immunoprecipitation Technology / 生物化学与生物物理进展

The UV cross-linking immunoprecipitation (CLIP) technique was first established in 2003. Sequences of target RNAs and binding sites of specific RNA-binding proteins (RBPs) were identified within the entire transcriptome by UV cross-linking, immunoprecipitation, reverse transcription, and subsequent high-throughput sequencing. Over the last 20 years, CLIP has been continuously modified and improved. Advanced operability and accuracy have extended its application category. Currently, the widely used CLIP technologies include high-throughput sequencing with crosslinking-immunoprecipitation (HITS-CLIP), photoactivatable-ribonucleoside-enhanced CLIP (PAR-CLIP), individual nucleotide resolution CLIP (iCLIP), enhanced CLIP (eCLIP), infrared-CLIP (irCLIP), etc. HITS-CLIP combines high-throughput sequencing with UV cross-linking immunoprecipitation. The 254 nm UV cross-linking and RNAase digestion steps allow the technology to capture transient intracellular RBP-RNA interactions. However, there are limitations in the efficiency of UV cross-linking, with low resolution and high intrinsic background noise. For PAR-CLIP, photoactivatable ribonucleoside was incorporated into RNA molecules, and RBP cross-linked with RNA by 365 nm UV light to improve cross-linking efficiency and resolution. Cross-linking mediated single-base mutations provide more accurate binding site information and reduce interference from background sequences. Long-term alternative nucleotide incorporation, on the other hand, can be cytotoxic and may skew experimental results. iCLIP can identify RBP-RNA cross-linking sites at the single nucleotide level through cDNA circularization and subsequent re-linearization steps, but it has more experimental procedures, and partial cDNAs lost in the circularization step are inevitable. eCLIP discards the radioisotope labeling procedure and reduces RNA loss by ligating adaptors in two separate steps, greatly improving the library-building efficiency, and reducing bias associated with PCR amplification; however, the efficiency of immunoprecipitation cannot be visually assessed at the early stage of the experiment. The irCLIP technique replaces radioisotopes with infrared dyes and greatly reduces the initial number of cells required for the experiment; however, an infrared imaging scanner is essential for the irCLIP application. To address more particular scientific issues, derivative CLIP-related techniques such as PAPERCLIP, cTag-PAPERCLIP, hiCLIP, and tiCLIP have also been developed in recent years. In practice, the aforementioned CLIP approaches have their advantages and disadvantages. When deciding on a technical strategy, we should take into account our experimental objectives and conditions, such as whether we need to precisely define the RNA site for binding to RBP; whether we have the necessary experimental conditions for working with radioisotopes or performing infrared imaging; the amount of initial sample size, and so on. In addition, the CLIP technique has a relatively large number of procedures and can be divided into several successive experimental modules. We can try to combine modules from different mainstream CLIP technologies to meet our experimental requirements, which also gives us more opportunities to improve and refine them and to build more targeted derivative CLIP technologies according to our research objectives.

Comparative analysis of the efficacy of RAPN and LPN in treating tumors in isolated kidney / 中华泌尿外科杂志

Objective:To compare the outcomes of robot-assisted laparoscopic partial nephrectomy (RAPN) and laparoscopic partial nephrectomy (LPN) in the treatment of tumors in isolated kidney, and analyze the factors influencing postoperative renal function and long-term survival in patients.Methods:A retrospective analysis was conducted on clinical data of 67 patients with tumors in isolated kidney who underwent surgery at the Chinese PLA General Hospital from November 2010 to January 2022. There were 48 males and 19 females, with an average age of (58.6±10.1) years old. The patients were divided into RAPN group (43 cases) and LPN group (24 cases) based on the surgical approach. The RAPN group had a higher R.E.N.A.L. score than the LPN group [(8.7±1.5) vs. (7.9±1.7), P=0.042]. There were no statistically significant differences between the two groups in terms of age [(57.4±10.2) years old vs. (60.9±9.8) years old, P=0.185], body mass index (BMI) [(25.7±3.5) kg/m 2 vs. (25.1±3.6) kg/m 2, P=0.518], and preoperative serum creatinine [(102.9±31.6) μmol/L vs. (102.3±22.4) μmol/L, P=0.930]. Twelve cases underwent hypothermic treatment during surgery, with 9 cases(20.9%) in the RAPN group and 3 cases(12.5%) in the LPN group( P=0.596). Surgical time, intraoperative warm ischemia time, intraoperative blood loss, postoperative fasting time, perioperative complication rate, postoperative serum creatinine, and other indicators were compared between the two groups. Multiple linear regression analysis was used to identify factors affecting postoperative serum creatinine. Kaplan-Meier curves were employed to analyze patient prognosis, and log-rank tests were performed to compare the differences between the two groups. Multiple Cox regression analysis was used to identify factors influencing patient prognosis. Results:All surgeries were completed successfully with negative pathological margins. There were no statistically significant differences between the RAPN and LPN groups in terms of surgical time [(136.6±47.6) min vs. (125.3±34.4) min, P=0.311], intraoperative ischemia time [23.0 (16.0, 30.0) min vs. 19.0 (13.5, 27.5) min, P =0.260], intraoperative blood loss [50.0 (50.0, 100.0) ml vs. 50.0 (22.5, 100.0) ml, P=0.247], postoperative hospital stay [(6.6±3.5) days vs. (7.7±4.2) days, P=0.244], time to drain removal [4(3, 5) days vs. 5(3, 6) days, P =0.175], postoperative fasting time [(2.1±0.7) days vs. (2.2±1.0) days, P=0.729], perioperative complication rate [18.6% (8/43) vs. 16.7% (4/24), P=1.000], postoperative serum creatinine [145.2 (128.3, 191.3) μmol/L vs. 157.8 (136.2, 196.3) μmol/L, P =0.229], and pathological staging [T 1a/T 1b/T 2a/T 3a/T 4 stage: 32/7/1/3/0 case vs. 17/5/0/1/1 case, P=0.804]. Kaplan-Meier survival curves showed that the total survival rates at 1, 3, and 5 years after surgery were 94.7%, 84.9%, and 84.9% for the RAPN group, and 100.0%, 95.5%, and 95.5% for the LPN group, with no statistically significant difference in the log-rank test ( P=0.116). Excluding 10 patients with preoperative tumor metastasis (7 in the RAPN group and 3 in the LPN group), the progression-free survival rates at 1, 3, and 5 years after surgery were 84.8%, 81.1%, and 81.1% for the RAPN group, and 100.0%, 95.0%, and 90.0% for the LPN group, with no statistically significant difference in the log-rank test ( P =0.142). Multiple linear regression analysis showed that the use of hypothermic treatment during surgery significantly reduced postoperative serum creatinine ( B=-72.191, P=0.048). Multiple Cox regression analysis revealed that BMI ( HR=0.743, P=0.044), pathological T stage ( HR=4.235, P=0.018), and preoperative metastasis ( HR=18.829, P=0.035) were independent factors affecting patient overall survival time. A smaller BMI, higher pathological stage, and preoperative metastasis were associated with poorer prognosis. Conclusions:Despite the higher R. E.N.A.L. score and greater surgical difficulty in the RAPN group, RAPN achieved similar perioperative and prognostic results as the LPN, indicating RAPN advantages in treating tumors in isolated kidney. Appropriate intraoperative hypothermic treatment can better protect postoperative renal function. BMI, pathological T stage, and preoperative metastasis are independent factors affecting overall survival time.

An anti-fouling wearable molecular imprinting sensor based on semi-interpenetrating network hydrogel for the detection of tryptophan in sweat.

The challenge of heavy biofouling in complex sweat environments limits the potential of electrochemical sweat sensors for noninvasive physiological assessment. In this study, a novel semi-interpenetrating hydrogel of PSBMA/PEDOT:PSS was engineered by interlacing PEDOT:PSS conductive polymer with zwitterionic PSBMA network. This versatile hydrogel served as the foundation for developing an anti-fouling wearable molecular imprinting sensor capable of sensitive and robust detection of tryptophan (Trp) in complex sweat. The incorporation of PEDOT:PSS conductive polymer into the semi-interpenetrating hydrogel introduced diverse physical crosslinks, including hydrogen bonding, electrostatic interactions, and chain entanglement. This incorporation considerably boosted the hydrogel's mechanical robustness and imparted commendable self-healing property. At the same time, the synergistic coupling between the well-balanced charge of the zwitterionic network and the high conductivity of the PEDOT:PSS polymer facilitated efficient charge transfer. The formation of the desired molecular imprinting membrane of semi-interpenetrating hydrogel was triggered by self-polymerization of dopamine (DA) in the presence of Trp. The designed biosensor demonstrated good sensitivity, selectivity and stability in detecting the target Trp. Notably, it also exhibited exceptional anti-fouling abilities, allowing for accurate Trp detection in complex real sweat samples, yielding results comparable to commercial enzyme-linked immunoassay (ELISA).

Target-triggered cascade signal amplification in nanochannels: An ingenious strategy for ultrasensitive photoelectrochemical DNA bioanalysis.

Artificial solid-state nanochannels have aroused intense interests in biosensors and bioelectronics because of their special architectures. Herein, we pioneered an ingenious approach of target-triggered cascade signal amplification in porous anodic aluminum oxide (AAO) nanochannels for ultrasensitive photoelectrochemical (PEC) DNA bioanalysis. In the design, AAO nanochannels were modified initially with capture DNA (cDNA) and then incorporated with a photoelectrode, yielding the desired architecture of highly ordered nanoarrays on top of the signal transducer. For target DNA (tDNA) probing, exonuclease III (Exo-III) mediated target recycling (ETR) was first activated to generate plenty of output DNA (oDNA) fragments. After oDNA and the conjugate of Au-labeled probe DNA (Au-pDNA) were anchored within the nanochannels via DNA hybridization, in-situ synthesis of Ag shells on tethered Au nanoparticles was conducted. The resulting large-sized Au@Ag core-shell nanostructure within the nanochannels would cause conspicuous blocking effect to hinder the transportation of electrons accessing the photoelectrode. Since the signal inhibition was directly related to tDNA concentration, an innovative nanochannels PEC DNA assay was exploited and qualified for ultrasensitive detection. The anti-interference ability of this platform was also emphasized by the split AAO membrane for biological incubation without participation of the photoelectrode. This featured nanochannels PEC strategy with cascade amplification launched a novel detecting platform for trace levels of DNA, and it could spark more inspiration for a follow-up exploration of other smart nanochannels PEC bioassays.

Engineered Branching Peptide as Dual-Functional Antifouling and Recognition Probe: Toward a Dual-Photoelectrode Protein Biosensor with High Accuracy.

The building of practical biosensors that have anti-interference abilities against biofouling of nonspecific proteins and biooxidation of reducing agents in actual biological matrixes remains a great challenge. Herein, a robust photoelectrochemical (PEC) biosensor capable of accurate detection in human serum was pioneered through the integration of a new engineered branching peptide (EBP) into a synergetic dual-photoelectrode system. The synergetic dual-photoelectrode system involved the tandem connection of a C3N4/TiO2 photoanode and a AuPt/PANI photocathode, while the EBP as a dual-functional antifouling and recognition probe featured an inverted Y-shaped configuration with one recognition backbone and two antifouling branches. Such an EBP enables a simple procedure for electrode modification and an enhanced antifouling nature compared to a regular linear peptide (LP), as theoretically supported by the results from molecular dynamics simulations. The as-developed PEC biosensor had a higher photocurrent response and a good antioxidation property inherited from the photoanode and photocathode, respectively. Targeting the model protein biomarker of cardiac troponin I (cTnI), this biosensor achieved good performances in terms of high sensitivity, specificity, and anti-interference.

Allosteric probe-triggered isothermal amplification to activate CRISPR/Cas12a for sensitive electrochemiluminescence detection of Salmonella.

We report an electrochemiluminescence (ECL) sensor for Salmonella detection based on allosteric probe as a bio-recognition element and CRISPR/Cas12a as a signal amplification strategy. In the presence of Salmonella, the structure switching occurs on allosteric probes, resulting in their hybridization with primers to trigger isothermal amplification. Salmonella is then released to initiate the next reaction cycle accompanying by generating a large amount of dsDNA, which are subsequently recognized by CRISPR-gRNA for activating the trans-cleavage activity of Cas12a. Furthermore, the activated Cas12a can indiscriminately cut the ssDNA which is bound to the electrode, enabling the release of the ECL emitter porphyrinic Zr metal - organic framework (MOF, PCN-224) and exhibiting a decreased ECL signal accordingly. The linear range is 50 CFU·mL-1-5 × 106 CFU·mL-1 and the detection limit is calculated to be 37 CFU·mL-1. This method sensitively detects Salmonella in different types of real samples, indicating it is a promising strategy for Salmonella detection.

Synergistic Incorporation of Two ssDNA Activators Enhances the Trans-Cleavage of CRISPR/Cas12a.

CRISPR/Cas12a has been believed to be powerful in molecular detection and diagnostics due to its amplified trans-cleavage feature. However, the activating specificity and multiple activation mechanisms of the Cas12a system are yet to be elucidated fully. Herein, a "synergistic activator effect" is discovered, which supports an activation mechanism that a synergistic incorporation of two short ssDNA activators can promote the trans-cleavage of CRISPR/Cas12a, while either of them is too short to work independently. As a proof-of-concept example, the synergistic activator-triggered CRISPR/Cas12a system has been successfully harnessed in the AND logic operation and the discrimination of single-nucleotide variants, requiring no signal conversion elements or other amplified enzymes. Moreover, a single-nucleotide specificity has been achieved for the detection of single-nucleotide variants by pre-introducing a synthetic mismatch between crRNA and the "helper" activator. The finding of "synergistic activator effect" not only provides deeper insight into CRISPR/Cas12a but also may facilitate its expanded application and power the exploration of the undiscovered properties of other CRISPR/Cas systems.

Compute-and-Release Logic-Gated DNA Cascade Circuit for Accurate Cancer Cell Imaging.

Accurate identification of cancer cells is an essential prerequisite for cancer diagnosis and subsequent effective curative interventions. The logic-gate-assisted cancer imaging system that allows a comparison of expression levels between biomarkers, rather than just reading biomarkers as inputs, returns a more comprehensive logical output, improving its accuracy for cell identification. To fulfill this key criterion, we develop a compute-and-release logic-gated double-amplified DNA cascade circuit. This novel system, CAR-CHA-HCR, consists of a compute-and-release (CAR) logic gate, a double-amplified DNA cascade circuit (termed CHA-HCR), and a MnO2 nanocarrier. CAR-CHA-HCR, a novel adaptive logic system, is designed to logically output the fluorescence signals after computing the expression levels of intracellular miR-21 and miR-892b. Only when miR-21 is present and its expression level is above the threshold CmiR-21 > CmiR-892b, the CAR-CHA-HCR circuit performs a compute-and-release operation on free miR-21, thereby outputting enhanced fluorescence signals to accurately image positive cells. It is capable of comparing the relative concentrations of two biomarkers while sensing them, thus allowing accurate identification of positive cancer cells, even in mixed cell populations. Such an intelligent system provides an avenue for highly accurate cancer imaging and is potentially envisioned to perform more complex tasks in biomedical studies.

A protein enzyme-free strategy for fluorescence detection of single nucleotide polymorphisms using asymmetric MNAzymes.

To establish protein enzyme-free and simple approach for sensitive detection of single nucleotide polymorphisms (SNPs), the nucleic acid amplification reactions were developed to reduce the dependence on protein enzymes (polymerase, endonuclease, ligase). These methods, while enabling highly amplified analysis for the short sequences, cannot be generalized to long genomic sequences. Herein, we develop a protein enzyme-free and general SNPs assay based on asymmetric MNAzyme probes. The multi-arm probe (MNAzyme-9M-13) with two asymmetric recognition arms, containing a short (9 nt) and a long (13 nt) arm, is designed to detect EGFR T790 M mutation (MT). Owing to the excellent selectivity of short recognition arm, MNAzyme-9M-13 probe can efficiently avoid interferences from wild-type target (WT) and various single-base mutations. Through a one-pot mixing, MNAzyme-9M-13 probe enables the sensitive detection of MT, without protein enzyme or multi-step operation. The calculated detection limit for MT is 0.59 nM and 0.83%. Moreover, this asymmetric MNAzyme strategy can be applied for SNPs detection in long genomic sequences as well as short microRNAs (miRNAs) only by changing the low-cost unlabeled recognition arms. Therefore, along with simple operation, low-cost, protein enzyme-free and strong versatility, our asymmetric MNAzyme strategy provides a novel solution for SNPs detection and genes analysis.

Design and simulation analysis of surgical micro-instrument based on flexible cable actuation / 医疗卫生装备

Objective To design a surgical micro-instrument based on flexible cable actuation and perform simulation analysis to eliminate the influences of the traditional surgical instruments on the precise operation of minimally invasive surgical procedures.Methods Firstly,the configuration design of the surgical micro-instrument was implemented based on the elastic element and flexible cable actuation,and the layout of the flexible cable was determined to optimize the flexible cable transmission mode.Secondly,the forward and inverse kinematic model of the surgical micro-instrument was constructed based on D-H method and then validated using MATLAB,and the workspace and singular shapes of the surgical micro-instrument were analysed.Finally,multi-case kinetic simulation analysis of the surgical micro-instrument was performed in conjunction with soft-tissue mechanical response,and sensitivity analysis of the effect of instrument-tissue interaction forces on joint driving torque was carried out.Results The surgical micro-instrument developed gained advantages in the accuracy of the forward and inverse kinematic model,the workspace and singular shapes for meeting surgical requirements and the sensitivity of joint driving torque for instrument-tissue interaction forces.Conclusion The surgical micro-instrument designed keeps the flexible cable in a tension state so as to satisfy the requirements for precision manipulation during actual minimally invasive surgery.