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1.
Chin Med J (Engl) ; 2020 Dec 02.
Artigo em Inglês | MEDLINE | ID: mdl-33273370

RESUMO

BACKGROUND: Patients with temporal lobe epilepsy (TLE) originating from different seizure onset zones had distinct electrophysiological characteristics and surgical outcomes. In this study, we aimed to investigate the relationship between the origin and prognosis of TLE, and the stereoelectroencephalography (SEEG) features. METHODS: Thirty patients with TLE, who underwent surgical treatment in our functional neurosurgery department from January 2016 to December 2017, were enrolled in this study. All patients underwent anterior temporal lobectomy after an invasive pre-operative evaluation with SEEG. Depending on the epileptic focus location, patients were divided into those with medial temporal lobe seizures (MTLS) and those with lateral temporal lobe seizures (LTLS). The Engel classification was used to evaluate operation effectiveness, and the Kaplan-Meier analysis was used to detect seizure-free duration. RESULTS: The mean follow-up time was 25.7 ±â€Š4.8 months. Effectiveness was 63.3% for Engel I (n = 19), 13.3% for Engel II, 3.3% for Engel III, and 20.0% for Engel IV. According to the SEEG, 60.0% (n = 18) had MTLS, and 40.0% (n = 12) had LTLS. Compared with the MTLS group, the operation age of those with LTLS was significantly greater (26.9 ±â€Š6.9 vs. 29.9 ±â€Š12.5 years, t = -0.840, P = 0.009) with longer epilepsy duration (11.9 ±â€Š6.0 vs. 17.9 ±â€Š12.1 years, t = -1.801, P = 0.038). Patients with MTLS had a longer time interval between ictal onset to seizure (67.3 ±â€Š59.1 s vs. 29.3 ±â€Š24.4 s, t = 2.017, P = 0.008). The most common SEEG ictal pattern was a sharp/spike-wave rhythm in the MTLS group (55.6%) and low-voltage fast activity in the LTLS group (58.3%). Compared with the LTLS group, patients with MTLS had a more favorable prognosis (41.7% vs. 77.8%, P = 0.049). Post-operative recurrence was more likely to occur within three months after the operation for both groups, and there appeared to be a stable long-term outcome. CONCLUSION: Patients with MTLS, who accounted for three-fifths of patients with TLE, showed a more favorable surgical outcome.

2.
Plant Dis ; 2020 Nov 24.
Artigo em Inglês | MEDLINE | ID: mdl-33231526

RESUMO

Sarcandra glabra is a species of Chloranthaceae family and this family grow in the southern part of China, Japan, and Southeastern Asia (Li et al. 2019). It is a kind of precious Chinese herbal medicine, which occupies an important position in traditional Chinese herbal medicine. It plays an effective role in the treatment of cancer, rheumatism, pneumonia, digestive tract inflammations, traumatic injuries and fractures, anti-virus, anti-bacterial, antioxidant, etc. (Li et al. 2019; Zheng et al. 2003; Zhou et al. 2013). Since June 2020, we discovered a serious leaf disease in the S. glabra planting base of Shibing County (108.12E 27.03N), in Guizhou Province, with an incidence rate of 60% and yield losses of 40%. Initially, the symptoms developed as small specks where spots were purple with a dark brown halo margin, and round or oval. In later stages, the spots gradually expanded and became dry, whole severe leaf loss. To identify the pathogen, we collected the diseased leaves from S. glabra fields in Shibing County. Small tissue pieces from the edges of lesions were disinfected in 75% ethyl alcohol for 30 s and 1% hypochlorite for 1 min, rinsed five times in sterile water, plated on potato dextrose agar (PDA), and incubated at 28°C in lighted incubator for 3 days. Fungal colonies were consistently isolated and transferred to PDA for morphological characterization (Fang et al. 2007). Pathogenicity tests of the novel isolate HGUP CSH-2 were conducted by spraying spore suspensions with a concentration of 1.6×108 conidia/ml on surface-disinfected (70% ethyl alcohol, 30 s) leaves, while sterile distilled water was used as the control. Plants with inoculated leaves (three per treatment) were placed in lighted growth chambers at 28°C for 5 days and watered as needed (Light to dark ratio 1:1, RH=90%). Symptoms on inoculated leaves were similar to those described previously in the field. The same pathogenic fungus was re-isolated from the infected leaves but not from the non-inoculated leaves. Colonies on PDA attaining 70 mm diam after 7 d at 28°C, with pale honey-colored, sparse aerial mycelia on the surface with black, gregarious conidiomata. Conidiogenous cell discrete or integrated, ampulliform, clavate or subcylindrical, hyaline, smooth-walled, wide at base. Conidia fusoid, ellipsoid, straight to slightly curved, 4-septate, slightly constricted at septa, 22.26-27.17×6.9-8.22 µm (av.±SD: 24.68±1.57×7.68±0.38 µm; n=30). According to the colony and conidia characteristics, the isolate was initially identified as Pestalotiopsis spp. (Liu et al. 2017). The pathogen was confirmed by amplification and sequencing of the internal transcribed spacer region (ITS) gene, the translation elongation factor-1 (TEF1) gene and the ß-tubulin (TUB2) gene (Liu et al. 2017) using ITS1/ITS4, Bt2a/T1 and EF1-526F/1567R primers, respectively. The sequences of the PCR products were deposited in GenBank with accession numbers MT919215 (ITS), MT939300 (TUB2) and MT939299 (TEF1). BLAST results of the obtained sequences of the ITS, TUB2 and TEF1 genes revealed 97.16% (479/493 nucleotides), 99.56% (675/678 nucleotides) and 99.89% (890/891 nucleotides) homology with those of Pestalotiopsis lushanensis in GenBank (MG726538, KY464157 and KX895223). Maximum Likelihood method was used for phylogenetic analysis. The result showed that HGUP CSH-2 was together with P. lushanensis with a support rate of 100%. According to the morphological characteristics and molecular phylogenetic analysis, the pathogen was identified as P. lushanensis. So far as we know, our research is the first report of brown leaf spot of S. glabra caused by P. lushanensis in China. Thus, identification of P. lushanensis for this disease is important for the advancement of effective prevention and control practises as future perspectives.

3.
Nanoscale ; 12(45): 22935-22944, 2020 Nov 26.
Artigo em Inglês | MEDLINE | ID: mdl-33180074

RESUMO

Layered transition-metal compounds with controllable magnetic behaviors provide many fascinating opportunities for the fabrication of high-performance magneto-electric and spintronic devices. The tuning of their electronic and magnetic properties is usually limited to the change of layer thickness, electrostatic doping, and the control of electric and magnetic fields. However, pressure has been rarely exploited as a control parameter for tailoring their magneto-electric properties. Here, we report a unique pressure-driven isostructural phase transition in layered CrCl3 accompanied by a simultaneous switching of magnetism from a ferromagnetic to an antiferromagnetic ordering. Our experiments, in combination with ab initio calculations, demonstrate that such a magnetic transition hinders the bandgap collapse under pressure, leading to an anomalous semiconductor-to-semiconductor transition. Our findings not only reveal the potential applications of this material in electronic and spintronic devices but also establish the basis for exploring unusual phase transitions in layered transition-metal compounds.

4.
Cell Death Dis ; 11(10): 912, 2020 Oct 24.
Artigo em Inglês | MEDLINE | ID: mdl-33099573

RESUMO

As important modulators in multiple physiological processes, microRNAs (miRNAs) have been reported in various malignant tumors, including breast cancer. The current study investigated the function of a new tumor suppressor microRNA, miR-488, and its molecular mechanism of metastasis in breast cancers. CCK8 and transwell assays revealed that the upregulated miR-488 level significantly inhibited the proliferation and migration of breast cancer cells. As a potential downstream gene, the mRNA and protein level of FSCN1 was suppressed by increased miR-488 and vice versa. Luciferase assay showed that miR-488 directly bind to the 3'UTR of FSCN1 and suppressed the translation process of FSCN1. The promoter region of miR-488 was directly bound by Notch3 and promoted the expression of miR-488 transcriptionally. Immunohistochemistry results revealed that in patients with breast cancer, the expression of Notch3 and were negatively correlated with the FSCN1 levels significantly. Therefore, the current finding predicted miR-488 as a tumor suppressor molecule in breast cancer, and demonstrated that Notch3/miR-488/FSCN1 axis is established and involved in regulating the metastasis of breast cancers, providing novel therapeutic targets for patients with breast cancers.

5.
Biosens Bioelectron ; 170: 112662, 2020 Dec 15.
Artigo em Inglês | MEDLINE | ID: mdl-33032198

RESUMO

Cancer cell enumeration and phenotyping can predict the prognosis and the therapy efficacy in patients, yet it remains challenging to detect the rare tumor cells. Herein, we report an octopus-inspired, bifunctional aptamer signal amplifier-based cytosensor (OApt-cytosensor) for sensitive cell analysis. By assembling high-affinity antibodies on an electrode surface, the target cells could be specifically captured and thus been sandwiched by the cell surface marker-specific DNA aptamers. These on-cell aptamers function as electrochemical signal amplifiers by base-selective electronic doping with methylene blue. Such a sandwich configuration enables highly sensitive cell detection down to 10 cells/mL (equal to ~1-2 cells at a sampling volume of 150 µL), even in a large excess of nontarget blood cells. This approach also reveals the cell-surface markers and tracks the cellular epithelial-to-mesenchymal transition induced by signaling regulators. Furthermore, the electron-doped aptamer shows remarkable cell fluorescent labeling that guides the release of the captured cells from electrode surface via electrochemistry. These features make OApt-cytosensor a promising tool in revealing the heterogeneous cancer cells and anticancer drug screening at the single-cell level.

6.
Infect Drug Resist ; 13: 2161-2170, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32753912

RESUMO

Purpose: Our study is a retrospective observational study conducted in one of the largest clinical centers of neurosurgery in China. We aimed to investigate the antimicrobial susceptibility patterns of the Enterobacteriaceae isolates responsible for nosocomial meningitis/encephalitis in post-neurosurgical patients. Meanwhile, we tried to evaluate the risk factors for mortality following Enterobacteriaceae meningitis/encephalitis. Patients and Methods: Medical data on clinical characteristics, antibiotic susceptibilities, and mortality were reviewed until patients' discharge or death in the hospital. Data for a total of 164 cerebrospinal fluid (CSF) infection cases due to Enterobacteriaceae after neurosurgery were collected between January 2014 and November 2019 in order to identify risk factors affecting the outcome. Kaplan-Meier survival analysis and multivariable Cox proportional hazard models were applied. Results: In this study, a total of 2416 neurosurgical meningitis/encephalitis cases were reported between 2014 and 2019. Enterobacteriaceae accounted for 7.3% (176/2416) of all the bacterial infections. Of them, 164 Enterobacteriaceae isolates were available to divide into two groups according to the final outcome of whether the patient died or survived. In total, 38 patients died (23.2%) and 126 patients survived (76.8%). The most frequent infecting species was Klebsiella pneumoniae (47.0%, 77/164). Fourteen-day and 30-day mortality rates were 7.9% (13/164) and 15.2% (25/164). Kaplan-Meier survival analysis revealed that the risk factors of Enterobacteriaceae meningitis/encephalitis that resulted in poor outcomes included comorbidities, Glasgow Coma Scale (GCS) score, sepsis, intensive care unit (ICU) admission, extended-spectrum beta-lactamase (ESBL)-producing Enterobacteriaceae, and ventilation. A GCS score of less than or equal to 8 (P=0.04, HR 2.562) was identified to be a significant risk factor for mortality according to the multivariable Cox proportional hazards model. Conclusion: In-hospital mortality caused by Enterobacteriaceae meningitis/encephalitis in neurosurgery was high. A GCS score of ≤8 was an independent risk factor for mortality following Enterobacteriaceae meningitis/encephalitis in post-neurosurgical patients.

7.
ACS Sens ; 5(8): 2514-2522, 2020 08 28.
Artigo em Inglês | MEDLINE | ID: mdl-32664724

RESUMO

MicroRNA (MiRNA)-based noninvasive diagnostics are hampered by the challenge in the quantification of circulating miRNAs using a general strategy. Here, we present a base-stacking effect-mediated ultrasensitive electrochemical miRNA sensor (BSee-miR) with a universal sandwich configuration. In the BSee-miR, a short DNA probe (10 nucleotides) self-assembled on a gold electrode surface could effectively capture the target miRNA synergizing with another sequence based on coaxial sandwich base-stacking, which rivals the fully complementary strength. Importantly, such a sandwich structure is flexible to incorporate signal amplification strategies (e.g., biotin-avidin) that are usually difficult to achieve in short sequence detection. Using this design, the BSee-miR achieves a broad dynamic range with a detection limit down to 7.5 fM. Furthermore, we found a high-curvature nanostructuring synergetic base-stacking effect that could improve the sensitivity of the BSee-miR by two orders of magnitude (79.3 aM). Our BSee-miR also has a single-base resolution to discriminate the highly homologous miRNAs. More importantly, this approach is universal and has been used to probe target miRNAs varying in sequences and secondary structures. Our ultrasensitive sensor could detect miRNA in cell lysates and human blood and distinguish cancer patients from normal individuals, promising a versatile tool to measure clinically relevant miRNAs for tumor diagnostics.

8.
Front Pharmacol ; 11: 924, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32636747

RESUMO

Nearly 70% of breast cancers express the estrogen receptor (ER) and are hormone-dependent for cell proliferation and survival. Anti-estrogen therapies with aromatase inhibitors (AIs), selective estrogen receptor modulators (SERMs) or selective estrogen receptor down regulators (SERDs) are the standard endocrine therapy approach for ER positive breast cancer patients. However, about 30% of patients receiving endocrine therapy will progress during the therapy or become endocrine resistance eventually. The intrinsic or acquired endocrine resistance has become a major obstacle for endocrine therapy. The mechanism of endocrine resistance is very complicated and recently emerging evidence indicates dysregulation of Notch signaling pathway contributes to endocrine resistance in breast cancer patients. The potential mechanisms include regulation of ER, promotion of cancer stem cell (CSC) phenotype and mesenchymal cell ratio, alteration of the local tumor microenvironment and cell cycle. This review will summarize the latest progress on the investigation of Notch signaling pathway in breast cancer endocrine resistance.

9.
Anal Chem ; 92(14): 9877-9886, 2020 07 21.
Artigo em Inglês | MEDLINE | ID: mdl-32551501

RESUMO

Exosome-associated liquid biopsies are hampered by challenges in the exosomal quantification and phenotyping. Here, we present a bioinspired exosome-activated DNA molecular machine (ExoADM) with multivalent cyclic amplification that enables highly sensitive detection and phenotyping of circulating exosomes. ExoADM harbors two (an exposed and a hidden) DNA toehold domains that actuate sequential branch migration and multivalent recycling in response to exosomal surface markers. Importantly, this self-powered ExoADM achieves a high sensitivity (33 particles/µL) and is compatible with another DNA nanomachine targeting different exosomal surface markers for dual-color phenotyping. Using this strategy, we can simultaneously track the dynamic changes of ExoPD-L1 and ExoCD63 expression induced by signaling molecules. Further, we found that their expression levels on circulating exosomes could well differentiate cancer patients from the normal individuals. More importantly, ExoPD-L1 levels could reflect the efficacy of different treatments and guide anti-PD-1 immunotherapy, suggesting the potential of ExoPD-L1 in clinical diagnosis and targeted therapy monitoring.

10.
Eur Respir J ; 56(1)2020 07.
Artigo em Inglês | MEDLINE | ID: mdl-32430428

RESUMO

BACKGROUND: The duration of viral shedding is central to the guidance of decisions about isolation precautions and antiviral treatment. However, studies regarding the risk factors associated with prolonged shedding of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and the impact of lopinavir/ritonavir (LPV/r) treatment on viral shedding remain scarce. METHODS: Data were collected from all SARS-CoV-2 infected patients who were admitted to isolation wards and had reverse transcription PCR conversion at the No. 3 People's Hospital of Hubei province, China, between 31 January and 9 March 2020. We compared clinical characteristics and SARS-CoV-2 RNA shedding between patients initiated with LPV/r treatment and those without. Logistic regression analysis was employed to evaluate the risk factors associated with prolonged viral shedding. RESULTS: Of 120 patients, the median age was 52 years, 54 (45%) were male and 78 (65%) received LPV/r treatment. The median duration of SARS-CoV-2 RNA detection from symptom onset was 23 days (interquartile range 18-32 days). Older age (OR 1.03, 95% CI 1.00-1.05; p=0.03) and the lack of LPV/r treatment (OR 2.42, 95% CI 1.10-5.36; p=0.029) were independent risk factors for prolonged SARS-CoV-2 RNA shedding. Patients who initiated LPV/r treatment within 10 days from symptom onset, but not initiated from day 11 onwards, had significantly shorter viral shedding duration compared with those without LPV/r treatment (median 19 days versus 28.5 days; log-rank p<0.001). CONCLUSION: Older age and the lack of LPV/r treatment were independently associated with prolonged SARS-CoV-2 RNA shedding in patients with coronavirus disease 2019 (COVID-19). Earlier administration of LPV/r treatment could shorten viral shedding duration.


Assuntos
Antivirais/uso terapêutico , Infecções por Coronavirus/tratamento farmacológico , Lopinavir/uso terapêutico , Pneumonia Viral/tratamento farmacológico , Ritonavir/uso terapêutico , Eliminação de Partículas Virais , Adulto , Fatores Etários , Idoso , Betacoronavirus , Estudos de Casos e Controles , Combinação de Medicamentos , Feminino , Hospitalização , Humanos , Masculino , Pessoa de Meia-Idade , Pandemias , Faringe/virologia , RNA Viral , Reação em Cadeia da Polimerase em Tempo Real , Estudos Retrospectivos , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Fatores de Tempo
11.
Front Cell Dev Biol ; 8: 160, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32300589

RESUMO

The maintenance of genomic stability is crucial for species survival, and its failure is closely associated with tumorigenesis. The Fanconi anemia (FA) pathway, involving 22 identified genes, plays a central role in repairing DNA interstrand cross-links. Importantly, a germline defect in any of these genes can cause Fanconi's anemia, a heterogeneous genetic disorder, characterized by congenital growth abnormalities, bone marrow failure, and predisposition to cancer. On the other hand, the breast cancer susceptibility genes, BRCA1 and BRCA2, also known as FANCS and FANCD1, respectively, are involved in the FA pathway; hence, researchers have studied the association between the FA pathway and cancer predisposition. Here, we mainly focused on and systematically reviewed the clinical and mechanistic implications of the predisposition of individuals with abnormalities in the FA pathway to cancer, especially breast cancer.

13.
Int J Cancer ; 147(2): 490-504, 2020 Jul 15.
Artigo em Inglês | MEDLINE | ID: mdl-32020593

RESUMO

Resistance to chemotherapy continues to be a critical issue in the clinical therapy of triple-negative breast cancer (TNBC). Epithelial-mesenchymal transition (EMT) is thought to contribute to chemoresistance in several cancer types, including breast cancer. Identification of the key signaling pathway that regulates the EMT program and contributes to chemoresistance in TNBC will provide a novel strategy to overcome chemoresistance in this subtype of cancer. Herein, we demonstrate that Notch1 positively associates with melanoma cell adhesion molecule (MCAM), a unique EMT activator, in TNBC tissue samples both at mRNA and protein levels. High expression of Notch1 and MCAM both predicts a poor survival in basal-like/TNBC patients, particularly in those treated with chemotherapy. The expression of Notch1 and MCAM in MDA-MB-231 cells gradually increases in a time-dependent manner when exposing to low dose cisplatin. Moreover, the expressions of Notch1 and MCAM in cisplatin-resistant MDA-MB-231 cells are significantly higher than wild-type counterparts. Notch1 promotes EMT and chemoresistance, as well as invasion and proliferation of TNBC cells via direct activating MCAM promoter. Inhibition of Notch1 significantly downregulates MCAM expression, resulting in the reversion of EMT and chemoresistance to cisplatin in TNBC cells. Our study reveals the regulatory mechanism of the Notch1 pathway and MCAM in TNBC and suggesting that targeting the Notch1/MCAM axis, in conjunction with conventional chemotherapies, might be a potential avenue to enhance the therapeutic efficacy for patients with TNBC.

14.
Anal Chem ; 92(5): 4006-4015, 2020 03 03.
Artigo em Inglês | MEDLINE | ID: mdl-32040907

RESUMO

Cancerous microvesicles (MVs), which are heterogeneous membrane-bound nanovesicles shed from the surfaces of cancer cells into the extracellular environment, have been widely recognized as promising "biofingerprints" for various cancers. High-performance identification of cancerous MVs plays a vital role in the early diagnosis of cancer, yet it is still technically challenging. Herein, we report a gold nanoparticle (AuNP)-decorated, dual-aptamer modified reduced graphene oxide (RGO) field-effect transistor (AAP-GFET) nanosensor for the label-free, specific, and sensitive quantification of HepG2 cell-derived MVs (HepG2-MVs). After GFET chips were fabricated, AuNPs were then decorated on the RGO surface. For specific capture and detection of HepG2-MVs, both sulfhydrylated HepG2 cell specific TLS11a aptamer (AptTLS11a) and epithelial cell adhesion molecule aptamer (AptEpCAM) were immobilized on the AuNP surface through an Au-S bond. This developed nanosensor delivered a broad linear dynamic range from 6 × 105 to 6 × 109 particles/mL and achieved a high sensitivity of 84 particles/µL for HepG2-MVs detection. Moreover, this AAP-GFET platform was able to distinguish HepG2-MVs from other liver cancer-related serum proteins (such as AFP and CEA) and MVs derived from human normal cells and other cancer cells of lung, pancreas, and prostate, suggesting its excellent method specificity. Compared with those modified with a single type of aptamer alone (AptTLS11a or AptEpCAM), such an AAP-GFET nanosensor showed greatly enhanced signals, suggesting that the dual-aptamer-based bio-nano interface was uniquely designed and could realize more sensitive quantification of HepG2-MVs. Using this platform to detect HepG2-MVs in clinical blood samples, we found that there were significant differences between healthy controls and hepatocellular carcinoma (HCC) patients, indicating its great potential in early HCC diagnosis.

15.
Int J Mol Sci ; 21(3)2020 Jan 21.
Artigo em Inglês | MEDLINE | ID: mdl-31973163

RESUMO

The transfer of genetic material from the mitochondria and plastid to the nucleus gives rise to nuclear integrants of mitochondrial DNA (NUMTs) and nuclear integrants of plastid DNA (NUPTs). This frequently occurring DNA transfer is ongoing and has important evolutionary implications. In this review, based on previous studies and the analysis of NUMT/NUPT insertions of more than 200 sequenced plant genomes, we analyzed and summarized the general features of NUMTs/NUPTs and highlighted the genetic consequence of organellar DNA insertions. The statistics of organellar DNA integrants among various plant genomes revealed that organellar DNA-derived sequence content is positively correlated with the nuclear genome size. After integration, the nuclear organellar DNA could undergo different fates, including elimination, mutation, rearrangement, fragmentation, and proliferation. The integrated organellar DNAs play important roles in increasing genetic diversity, promoting gene and genome evolution, and are involved in sex chromosome evolution in dioecious plants. The integrating mechanisms, involving non-homologous end joining at double-strand breaks were also discussed.


Assuntos
Núcleo Celular/genética , Evolução Molecular , Genoma de Planta , Plantas/genética , Plastídeos/genética , Proliferação de Células/genética , Reparo do DNA por Junção de Extremidades , DNA de Cloroplastos/genética , DNA Mitocondrial/genética , Tamanho do Genoma , Mitocôndrias/genética , Mutação , Cromossomos Sexuais
16.
ACS Sens ; 5(2): 362-369, 2020 02 28.
Artigo em Inglês | MEDLINE | ID: mdl-31933360

RESUMO

In this study, we report a gold nanoparticle (AuNP)-amplified surface acoustic wave (SAW) sensor for exosome detection with high sensitivity. The SAW chip was self-assembled with mercapto acetic acid to generate carboxylic groups via the Au-S bond. Anti-CD63 was then anchored onto the chip by pretreatment with 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride (EDC) and N-hydroxysuccinimide,1-hydroxypyrrolidine-2,5-dione (NHS). Due to the existence of a membrane protein, CD63, on the exosome surface, exosomes could be bound onto the antibody-immobilized SAW chip. To amplify the detection signal, both the biotin-conjugated epithelial cell adhesion molecule (EpCAM) antibody as a secondary antibody and AuNP-labeled streptavidin were applied onto the exosome-bound SAW chip, resulting in AuNP assembly on the chip through biotin-avidin recognition. The sensor was capable of detecting 1.1 × 103 particles/mL exosomes, which was about 2 orders of magnitude higher than those detected by the strategy without using signal amplification. The sensor also achieved a satisfactory specificity and could detect the low-abundance exosomes directly in blood samples from cancer patients with minimal disturbance. This makes the SAW sensor useful for early diagnosis of cancer.

17.
Anal Chem ; 92(2): 2136-2144, 2020 01 21.
Artigo em Inglês | MEDLINE | ID: mdl-31849210

RESUMO

It remains a technical challenge to accurately identify close species of herbal medicines, especially from adulterants, because of their highly identical phenotypes and chemical compositions. Here, we report a direct, sequencing-free, high-curvature nanostructuring-based electrochemical herb sensor (nanoE-herb sensor) to identify herbal species quickly and accurately using ITS2 barcodes. We engineer a nano-roughened carbon-supported gold nanostructuring array by photolithograph-free, one-step electrodeposition. The 3D fractal nanostructures exhibit a high deflection angle that largely enhances DNA hybridization efficiency, particularly for the midcomplementary hybridization, as compared to the 2D planar surface. More importantly, such a trans-scale array biointerface (including macroscale carbon and nanoscale gold branches) can overcome the detection barrier of slow diffusion of a long genomic sequence and inaccessibility of the sequestered variations in ITS2 secondary structures through the out-protruded 3D functional nanostructures. Our nanoE-herb sensor achieves a detection limit of 0.18 fM for the 64-mer fragment of saffron ITS2 barcode with midhybridization and shows superior specificity against even single-base mismatch. The sensor also precisely differentiates saffron from six other adulterants by directly detecting unpurified asymmetric PCR amplicons (∼500 bp) with ITS2 sequences, suggesting its great potential in the field identification of herbal medicinal species and pathogenic bacteria with specific DNA barcodes.

18.
Anal Chem ; 91(20): 13198-13205, 2019 10 15.
Artigo em Inglês | MEDLINE | ID: mdl-31553171

RESUMO

Exosomal microRNAs are essential in intercellular communications and disease progression, yet it remains challenging to quantify the expression level due to their small size and low abundance in blood. Here, we report a "sandwich" electrochemical exosomal microRNA sensor (SEEmiR) to detect target microRNA with high sensitivity and specificity. In SEEmiR, neutrally charged peptide nucleic acid (PNA) enables kinetically favorable hybridization with the microRNA target relative to negatively charged DNA, particularly in a short sequence (10 nt). More importantly, this property allows PNA to cooperate with a spherical nucleic acid (SNA) nanoprobe that heavily loads with oligonucleotide-adsorbed electroactive tags to enhance detection sensitivity and specificity. Such a PNA-microRNA-SNA sandwich construct is able to minimize the background noise via PNA, thereby maximizing the SNA-mediated signal amplification in electrostatic adsorption-based SEEmiR. The synergy between PNA and SNA makes the SEEmiR sensor able to achieve a broad dynamic range (from 100 aM to 1 nM) with a detection limit down to 49 aM (2 orders of magnitude lower than that without SNA) and capable of distinguishing a single-base mismatch. This ultrasensitive sensor provides label-free and enzyme-independent microRNA detection in cell lysates, unpurified tumor exosomal lysates, cancer patients' blood, and accurately differentiates the patients with breast cancer from the healthy ones, suggesting its potential as a promising tool in cancer diagnostics.


Assuntos
Técnicas Eletroquímicas/métodos , Exossomos/química , MicroRNAs/sangue , Ácidos Nucleicos Peptídicos/química , Linhagem Celular Tumoral , Ouro/química , Humanos , Limite de Detecção , Nanopartículas Metálicas/química , MicroRNAs/genética , Hibridização de Ácido Nucleico , Ácidos Nucleicos Peptídicos/genética
19.
Analyst ; 144(20): 6055-6063, 2019 Oct 07.
Artigo em Inglês | MEDLINE | ID: mdl-31517337

RESUMO

Unlike other extracellular vesicle (EV) subtypes such as exosomes, the lack of well-defined universal markers on the surface of microvesicles (MVs) has led to difficulty in the detection of the entire MV population. To design a universal MV detection method, we reported highly sensitive electrical detection of MVs using a reduced graphene oxide (RGO)-based field-effect transistor (FET) biosensor by the introduction of a membrane biotinylation strategy in this work. Biotinylated MVs (B-MVs) were obtained by supplying the culture medium with 1,2-distearoyl-sn-glycero-3-phosphoethanolamine-N-[biotinyl(polyethylene glycol)-2000] (DSPE-PEG-biotin) while cultivating the cells. Excellent biotinylation efficiency of MVs (92.6%) was then realized. A streptavidin (SA) probe was subsequently modified onto the channel surface of the as-fabricated RGO-based FET device, which was capable of specifically recognizing B-MVs due to the high affinity between SA and biotin in a 1 : 4 recognition format. The results showed that the RGO-based FET biosensor could detect B-MVs in a wide range from 105 particles per mL to 109 particles per mL with a low detection limit down to 20 particles per µL, which was the lowest value compared with other previously reported results. This platform also allowed distinguishing B-MVs from other unbiotinylated EV types such as MVs and exosomes, exhibiting excellent specificity. Moreover, this FET biosensor demonstrated the capability of detecting B-MVs derived from different cell lines including cancer cells and normal cells, indicating its versatility and potential applications in the biomedical field.


Assuntos
Técnicas Biossensoriais/métodos , Biotina/metabolismo , Micropartículas Derivadas de Células/metabolismo , Exossomos/metabolismo , Grafite/química , Neoplasias Hepáticas/metabolismo , Fígado/metabolismo , Biotinilação , Células Endoteliais da Veia Umbilical Humana , Humanos , Fosfatidiletanolaminas/química , Polietilenoglicóis/química , Estreptavidina/metabolismo , Transistores Eletrônicos
20.
Anal Chem ; 91(16): 10679-10686, 2019 08 20.
Artigo em Inglês | MEDLINE | ID: mdl-31331170

RESUMO

Exosomes are small membrane-bound nanovesicles with a size of 50-150 nm which contain many functional biomolecules, such as nucleic acids and proteins. Due to their high homology with parental generation, they are of great significance in clinical diagnosis. At present, the quantitative detection of low concentrations of cancer-derived exosomes present in biofluids is still a great challenge. In this study, we develop an electrical and label-free method to directly detect exosomes with high sensitivity based on a reduced graphene oxide (RGO) field effect transistor (FET) biosensor. An RGO FET biosensor modified with specific antibody CD63 in the sensing area was fabricated and was used for electrical and label-free quantification of exosomes. The method achieved a low limit of detection down to 33 particles/µL, which is lower than that of many other available methods. In addition, the FET biosensor was employed to detect exosomes in clinical serum samples, showing significant differences in detecting healthy people and prostate cancer (PCa) patients. Different from other technologies, this study provides a unique technology capable of directly quantifying exosomes without labeling, indicating its potential as a tool for early diagnosis of cancer.


Assuntos
Técnicas Biossensoriais , Exossomos/química , Grafite/química , Neoplasias da Próstata/diagnóstico por imagem , Humanos , Masculino , Oxirredução , Transistores Eletrônicos
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