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1.
ACS Sens ; 6(11): 4225-4233, 2021 Nov 26.
Artigo em Inglês | MEDLINE | ID: mdl-34709795

RESUMO

Adenosine triphosphate (ATP) acts as the main energy source for growth and development in organisms, and the disorder reflects the mitochondrial damage to a large extent. Therefore, an efficient tool for the evaluation of the ATP metabolic level is important to track mitochondrial health, providing an additional perspective for an in-depth long-term study on living activities. Herein, a twisted intramolecular charge transfer (TICT) framework is utilized to build up a sensitive receptor, Mito-VP, with a negligible background to target mitochondrial ATP metabolism by monitoring the phosphate ion (Pi) level upon ATP hydrolysis under the overall consideration of the structural and functional features of mitochondria. The responsive fluorescence could be lighted on under the dual control of Pi and local microviscosity, and the two steps of ATP hydrolysis could be captured through fluorescence. In addition to the well-behaved mitochondrial targeting, the energy metabolism at cellular and organism levels has been clarified via mitosis and zebrafish development, respectively.

2.
J Hazard Mater ; 416: 125988, 2021 08 15.
Artigo em Inglês | MEDLINE | ID: mdl-34492885

RESUMO

It is important to develop highly-active photoelectrochemical (PEC) materials and use novel sensing strategy for constructing high-PEC-performance sensors with multiplex detection abilities, owing to the simultaneous presence of multiple antibiotic residues in food. Herein, a bias-potential-based PEC aptasensor was prepared for the trace detection of dual antibiotic analytes, enrofloxacin (ENR) and ciprofloxacin (CIP), which often coexist in milk samples. Here, two materials were developed with excellent PEC performance: three-dimensional nitrogen-doped graphene-loaded copper indium disulfide (CuInS2/3DNG) and Bi3+-doped black anatase titania nanoparticles decorated with reduced graphene oxide (Bi3+/B-TiO2/rGO). By applying different bias potentials to the two materials near one ITO electrode, the cathodic current generated by CuInS2/3DNH and the anodic current generated by Bi3+/B-TiO2/rGO could be clearly distinguished without interfering with each other. Then, ENR and CIP aptamers were respectively modified onto the surface of CuInS2/3DNH and Bi3+/B-TiO2/rGO to construct a PEC aptasensor for the sensitive detection of ENR and CIP. Under optimal conditions, the proposed aptasensor exhibited wide linear ranges of ENR (0.01-10000 ng/mL) and CIP (0.01-1000 ng/mL), and relatively low detection limits of 3.3 pg/mL to ENR and CIP (S/N = 3). The aptasensor was successfully applied to the detection of ENR and CIP in milk samples.


Assuntos
Aptâmeros de Nucleotídeos , Técnicas Biossensoriais , Grafite , Animais , Ciprofloxacina , Técnicas Eletroquímicas , Enrofloxacina , Limite de Detecção , Leite
3.
Anal Chem ; 93(32): 11337-11345, 2021 08 17.
Artigo em Inglês | MEDLINE | ID: mdl-34353021

RESUMO

Alzheimer's disease (AD) has become a global threat to the elderly health with a short survival time after diagnosis. Due to the asymptomatic stage during the early development, patients are usually diagnosed at the middle or late stage. Therefore, an efficient tool for AD early diagnosis deserves considerable attention, which could make a significant contribution to the treatment intervention. A fluorescent probe has been widely applied for detecting and visualizing species of interest in vitro and in vivo, and the proper reaction between the probe and analytes is responsible for the fluorescence change to provide a lighting-on or ratiometric responsive pattern with satisfactory sensing behavior. In this work, we report the first attempt to build up an AND-logic probe P2 for AD accuracy diagnosis taking butyrylcholinesterase (BChE) and reactive oxygen species (ROSs) as dual targets. Upon the co-stimulation by these two factors through enzymatic hydrolysis and redox reaction, the NIR emission could be readily turned on. This AND sensing pattern avoided the false-positive response effectively, and other diseases sharing one biomarker could hardly induce a NIR fluorescence response. The sensing assay has also been confirmed to be feasible in vitro and in vivo with good sensibility and selectivity. It is worth mentioning that the probe structure has been optimized in terms of the linkage length. This study shows that probe P2 with a connecting arm of medium length (one methylene, n = 1) has superior sensing performance, promising to provide a reference for the relative structure design.


Assuntos
Doença de Alzheimer , Corantes Fluorescentes , Idoso , Doença de Alzheimer/diagnóstico , Biomarcadores , Butirilcolinesterase , Humanos , Lógica
4.
Anal Chem ; 93(30): 10679-10687, 2021 08 03.
Artigo em Inglês | MEDLINE | ID: mdl-34288646

RESUMO

Herein, an electrochemiluminescence (ECL) microRNA biosensor based on anti-fouling magnetic beads (MBs) and two signal amplification strategies was developed. The newly designed anti-fouling dendritic peptide was wrapped on the surfaces of MBs to make them resistant to nonspecific adsorption of biomolecules in complex biological samples so as to realize accurate and selective target recognition. One of the amplification strategies was achieved through nucleic acid cycle amplification based on the DNAzyme on the surfaces of MBs. Then, the output DNA generated by the nucleic acid cycle amplification program stimulated the hybrid chain reaction (HCR) process on the modified electrode surface to generate the other amplification of the ECL response. Titanium dioxide nanoneedles (TiO2 NNs), as a co-reaction accelerator of the Ru(bpy)2(cpaphen)2+ and tripropylamine (TPrA) system, were wrapped with the electrodeposited polyaniline (PANI) on the electrode surface to enhance the ECL intensity of Ru(bpy)2(cpaphen)2+. The conducting polymer PANI can not only immobilize the TiO2 NNs but also improve the conductivity of the modified electrodes. The biosensor exhibited ultra-high sensitivity and excellent selectivity toward the detection of miRNA 21, with a detection limit of 0.13 fM. More importantly, with the anti-fouling MBs as a unique separation tool, this ECL biosensor was capable of assaying targets in complex biological media such as serum and cell lysate.


Assuntos
Incrustação Biológica , Técnicas Biossensoriais , MicroRNAs , Incrustação Biológica/prevenção & controle , Técnicas Eletroquímicas , Medições Luminescentes , Fenômenos Magnéticos
5.
Org Lett ; 23(15): 5782-5786, 2021 08 06.
Artigo em Inglês | MEDLINE | ID: mdl-34270896

RESUMO

Alstoscholarisine K, an indole alkaloid with eight chiral carbons and featuring a novel 6/5/6/6/6/6/6/5 octacyclic architecture, was found to be specific to the gall-infected leaves of Alstonia scholaris. Its structure was elucidated by spectroscopy, computational analysis, and single-crystal X-ray diffraction. The unusual highly fused cage-like pyrrolo[1,2-a]pyrimidine structure with an additional -C4N unit is possibly derived from a combination of monoterpenoid indole and polyamine pathways. The fascinating compound exhibited significant antibacterial bioactivities by targeting cell membranes.


Assuntos
Alstonia/química , Antibacterianos/farmacologia , Anti-Infecciosos/farmacologia , Alcaloides Indólicos/química , Alcaloides Indólicos/farmacologia , Monoterpenos/farmacologia , Antibacterianos/química , Antibacterianos/isolamento & purificação , Anti-Infecciosos/química , Anti-Infecciosos/isolamento & purificação , Cristalografia por Raios X , Alcaloides Indólicos/isolamento & purificação , Espectroscopia de Ressonância Magnética , Estrutura Molecular , Monoterpenos/química , Monoterpenos/isolamento & purificação , Folhas de Planta/química
6.
ACS Appl Mater Interfaces ; 13(28): 32837-32844, 2021 Jul 21.
Artigo em Inglês | MEDLINE | ID: mdl-34236165

RESUMO

Exosomes, which can transfer and deliver information about the original cell, are considered to be ideal candidates for early cancer diagnosis and evaluation of therapeutic efficacy due to their high abundance and stability. However, the highly expressed proteins on the surface of exosomes are usually associated with a variety of cancers; it is difficult to distinguish them by a single marker. Herein, a controlled self-assembly of gold nanorod (AuNR) arrays was prepared to construct a surface-enhanced Raman spectroscopy (SERS) sensor for the specific detection of exosomes secreted by SK-Br-3 cells based on a designed colocalization-dependent system (Co-DNA-Locker) and ratiometric strategy. After the exosomes are captured in the sensing array by the EpCAM aptamer modified on the surface of AuNRs, the DNA logic process occurs because the other two proteins, CD63 and HER2, are expressed simultaneously on the surface of exosomes secreted by SK-Br-3 cells, and the SERS signal intensity of the Rhodamine 6G (R6G) tagged on the terminal of DNA TE increased with an increase in the concentration of the exosomes, while the SERS signal intensity of Cy5 linked on the terminal of the EpCAM aptamer, which acts as an internal standard, remains stable. The AuNRs are uniformly arranged in a hexagonal shape, and the dense "hot spots" produce "hot surfaces," which greatly improve the sensitivity and uniformity of detection. In the presence of target exosomes, the DNA colocalization three-signal input switch and the ratiometric strategy realize the specific and accurate detection of exosomes. This sensing strategy achieves a wide detection range (1.0 × 104-5.0 × 106 particles/mL) and a lower detection limit (5.3 × 103 particles/mL), without using any signal amplification mechanism, demonstrating promising applications in health care monitoring and clinical diagnostics.


Assuntos
Aptâmeros de Nucleotídeos/química , DNA/química , Exossomos , Nanotubos/química , Aptâmeros de Nucleotídeos/genética , Aptâmeros de Nucleotídeos/metabolismo , Técnicas Biossensoriais/métodos , Carbocianinas/química , Linhagem Celular Tumoral , DNA/genética , DNA/metabolismo , Exossomos/química , Exossomos/metabolismo , Corantes Fluorescentes/química , Ouro/química , Células HEK293 , Humanos , Limite de Detecção , Hibridização de Ácido Nucleico , Receptor ErbB-2/metabolismo , Rodaminas/química , Análise Espectral Raman/métodos , Tetraspanina 30/metabolismo
7.
Mikrochim Acta ; 188(8): 253, 2021 07 14.
Artigo em Inglês | MEDLINE | ID: mdl-34263415

RESUMO

MicroRNA-21 is an important biomarker of tumor early prediction and metastasis, and its accurate detection is of great significance for tumor diagnosis and treatment. It will be a meaningful work to combine the detection of RNA with chemotherapy and photothermal therapy on the same composite material. Herein, we designed a multifunctional nanocomposite based on gold nanorods (AuNRs), making use of microRNA-triggered drug release and near-infrared photothermal effect, which has been developed for cancer therapy and microRNA-21detection. Firstly, the AuNRs with photothermal effect were synthesized as carriers for drug delivery. Then the surface of gold nanorods was modified by functional DNA chains to provide an efficient site for doxorubicin (DOX) loading. Finally, folic acid was introduced to achieve the targeted treatment of MCF-7 cells. The microRNA competed with the double-stranded DNA, resulting in the release of DOX and the recovery of fluorescence signal located at 595 nm with an excitation of 488 nm effectively. The nano-biosensor could not only achieve dual-function of diagnosis and treatment of cancer cells, but also accomplish the detection of microRNA in tumor cells. It showed a high selectivity for microRNA-21 determination with a limit of detection (LOD) of 2.1 nM from the linear relationship from 1.0 × 10-5 M to 5.0 × 10-7 M. This scheme provides an outstanding strategy for cell imaging, treatment, and detection, which serves as a promising candidate in the field of biomedical research.

8.
ACS Appl Mater Interfaces ; 13(17): 20388-20396, 2021 May 05.
Artigo em Inglês | MEDLINE | ID: mdl-33878863

RESUMO

A universal strategy for the construction of ratiometric antifouling electrochemical biosensors was developed based on multifunctional peptides and 2D nanomaterial MXene loaded with gold nanoparticles (AuNPs) and methylene blue (MB). The nanocomposite of MXene loaded with AuNPs and MB (MXene-Au-MB) exhibited excellent conductivity, where the AuNPs were able to capture biomolecules containing sulfhydryl terminus, and the MB molecules were used to generate electrochemical signal. The MXene-Au-MB was fixed on the electrode surface by Nafion, and the anchored peptide captured the electrochemical signal probe carboxyl-modified ferrocene (Fc) to construct an electrochemical biosensor. The multifunctional peptide containing the anchoring, antifouling, and recognizing sequences endowed the sensing surface not only the assaying function but also the capability to resist nonspecific adsorption from complex samples. In the biosensing system, with the increase in the target concentration, the electrochemical signal of MB remained constant, whereas the electrochemical signal of Fc gradually decreased, and the ratiometric detection strategy greatly improved the accuracy of the biosensor. In the presence of a model target prostate-specific antigen (PSA), the recognizing sequence was recognized and cleaved, and the ratiometric signal of Fc and MB indicated the concentration of PSA accurately and sensitively, with a detection range from 5 pg/mL to 10 ng/mL and a limit of detection of 0.83 pg/mL. Electrochemical biosensors based on the MXene-Au-MB and multifunctional peptides possessed high selectivity, accuracy, and sensitivity even in real complex biological samples because of the excellent antifouling ability of the peptide. More importantly, the assaying of other targets can be easily realized with a similar biosensing strategy by changing the recognition sequence of the multifunctional peptide, and the detection of thrombin (TB) has also been achieved in this work.


Assuntos
Técnicas Biossensoriais/instrumentação , Técnicas Eletroquímicas/métodos , Ouro/química , Nanopartículas Metálicas/química , Azul de Metileno/química , Peptídeos/química , Microscopia Eletrônica de Varredura , Espectrometria por Raios X , Difração de Raios X
9.
Nat Prod Res ; : 1-7, 2021 Apr 28.
Artigo em Inglês | MEDLINE | ID: mdl-33908330

RESUMO

A new alkaloid 14-hydroxygelseziridine (1), along with four known oxindoles (2-5), was isolated and characterized from the well-known toxic medicine Gelsemium elegans. Their structures were elucidated by means of spectroscopic techniques and quantum chemistry calculations. Structurally, new compound 1 has a three membered oxygen ring at N-4/C-20. All compounds were tested for osteoclast (MOC-1) inhibitory activity in vitro. Compound 2 exhibited the selective osteoclast inhibitory activity. Flow cytometry revealed that the apoptosis of osteoclasts induced by 2. Furthermore, the PCR bioassay suggested that compound 2 may activate the apoptotic pathway of osteoclasts by reducing the expression of IL-6 and c-Jun, and increasing caspase 9. This work provided the evidence for the rationality as the traditional treatment for bone related diseases of G. elegans, and shed a new light on its further research.

10.
Anal Chem ; 93(14): 5963-5971, 2021 04 13.
Artigo em Inglês | MEDLINE | ID: mdl-33797892

RESUMO

Biofouling caused by the accumulation of biomolecules on sensing surfaces is one of the major problems and challenges to realize the practical application of electrochemical biosensors, and an effective way to counter this problem is the construction of antifouling biosensors. Herein, an antifouling electrochemical biosensor was constructed based on electropolymerized polyaniline (PANI) nanowires and newly designed peptides for the detection of the COVID-19 N-gene. The inverted Y-shaped peptides were designed with excellent antifouling properties and two anchoring branches, and their antifouling performances against proteins and complex biological media were investigated using different approaches. Based on the biotin-streptavidin affinity system, biotin-labeled probes specific to the N-gene (nucleocapsid phosphoprotein) of COVID-19 were immobilized onto the peptide-coated PANI nanowires, forming a highly sensitive and antifouling electrochemical sensing interface for the detection of COVID-19 nucleic acid. The antifouling genosensor demonstrated a wide linear range (10-14 to 10-9 M) and an exceptional low detection limit (3.5 fM). The remarkable performance of the genosensor derives from the high peak current of PANI, which is chosen as the sensing signal, and the extraordinary antifouling properties of designed peptides, which guarantee accurate detection in complex systems. These crucial features represent essential elements for future rapid and decentralized clinical testing.


Assuntos
Técnicas Biossensoriais , Técnicas Eletroquímicas , RNA Viral/isolamento & purificação , SARS-CoV-2/genética , Humanos , Sondas Moleculares , Peptídeos
11.
Anal Chim Acta ; 1154: 338295, 2021 Apr 15.
Artigo em Inglês | MEDLINE | ID: mdl-33736817

RESUMO

A unique electrochemical sensor was constructed based on designed peptide hydrogels loaded with ciprofloxacin and gold nanoparticles, which exhibited excellent biocompatibility, antibacterial capability and electrochemical catalytic property. The peptide hydrogel was prepared base on the self-assembly of a designed short peptide sequence of Phe-Glu-Lys-Phe (FEKF) with the N-terminal modified with a fluorene methoxycarbonyl (Fmoc) group. The peptide hydrogel possessed nanofibrous network structure and exhibited good shear-thinning behavior and excellent biocompatibility, and it can be easily doped with gold nanoparticles and the antibiotic drug ciprofloxacin. The loaded antibacterial drug offered remarkable antibacterial activity of the hydrogel, while the loaded gold nanoparticles rendered the hydrogel excellent electrochemical catalytic capability towards the detection of a typical neurotransmitter dopamine. The combination of the antibacterial property and the electrochemical catalytic ability within a peptide hydrogel ensured the development of sensitive and antibacterial electrochemical sensors, and this strategy was expected to promote the construction of implantable sensors without infection.


Assuntos
Hidrogéis , Nanopartículas Metálicas , Antibacterianos/farmacologia , Ouro , Peptídeos
12.
J Hazard Mater ; 414: 125539, 2021 07 15.
Artigo em Inglês | MEDLINE | ID: mdl-33667805

RESUMO

Sensitive detection of streptomycin (STR) has attracted increasing attention worldwide because of the relationship between food security and human health. In this paper, Bi4VO8Br/Ti3C2 nanohybrids were obtained by one-pot solvent hydrothermal method. It was modified on ITO electrode, and STR aptamer was acted as the recognition element. With excellent photoelectrochemical (PEC) performance of Bi4VO8Br/Ti3C2 nanohybrids, an "on-off-on" PEC aptasensor for STR detection was effectively developed. Compared with pure Bi4VO8Br, the photocurrent intensity of as-prepared Bi4VO8Br/Ti3C2 nanohybrids was about 9 times higher, which ascribed to the highly conductive of Ti3C2, driving the photogenerated electrons transferred to the ITO electrode rapidly, so that the recombination of photogenerated electron and hole pairs was inhibited viably. Furthermore, the constructed "on-off-on" PEC aptasensor accomplished STR detection with high sensitivity, excellent specificity and distinguished repeatability in honey. The photocurrent increased with the increment of STR concentration with the linear range from1 nM to 1000 nM, and the detection limit of 0.3 nM (S/N = 3). Compared with the national standard method (SN/T 1925-2007), the as-constructed PEC sensor showed the consistent results.


Assuntos
Aptâmeros de Nucleotídeos , Técnicas Biossensoriais , Técnicas Eletroquímicas , Humanos , Limite de Detecção , Estreptomicina , Titânio
13.
ACS Appl Mater Interfaces ; 13(9): 10674-10688, 2021 Mar 10.
Artigo em Inglês | MEDLINE | ID: mdl-33621058

RESUMO

Cyclodextrins (CDs), as pharmaceutical excipients with excellent biocompatibility, non-immunogenicity, and low toxicity in vivo, are widely used to carry drugs by forming inclusion complexes for improving the solubility and stability of drugs. However, the limited space of CDs' lipophilic central cavity affects the loading of many drugs, especially with larger molecules. In this study, ß-CDs were modified by acetonization to improve the affinity for the chemotherapy drug doxorubicin (DOX), and doxorubicin-adsorbing acetalated ß-CDs (Ac-CD:DOX) self-assembled to nanoparticles, followed by coating with the amphiphilic zinc phthalocyanine photosensitizer ZnPc-(PEG)5 for antitumor therapy. The final product ZnPc-(PEG)5:Ac-CD:DOX was demonstrated to have excellent stability and pH-sensitive drug release characteristics. The cell viability and apoptosis assay showed synergistic cytotoxic effects of chemotherapy and phototherapy. The mechanism of cytotoxicity was analyzed in terms of intracellular reactive oxygen species, mitochondrial membrane potential, and subcellular localization. More importantly, in vivo experiments indicated that ZnPc-(PEG)5:Ac-CD:DOX possessed significant tumor targeting, prominent antitumor activity, and less side effects. Our strategy expands the application of CDs as drug carriers and provides new insights into the development of CD chemistry.


Assuntos
Antineoplásicos/uso terapêutico , Doxorrubicina/uso terapêutico , Portadores de Fármacos/uso terapêutico , Nanopartículas/uso terapêutico , Neoplasias/tratamento farmacológico , Animais , Antineoplásicos/química , Apoptose/efeitos dos fármacos , Doxorrubicina/química , Portadores de Fármacos/síntese química , Portadores de Fármacos/efeitos da radiação , Liberação Controlada de Fármacos , Sinergismo Farmacológico , Células Hep G2 , Humanos , Concentração de Íons de Hidrogênio , Indóis/síntese química , Indóis/efeitos da radiação , Indóis/uso terapêutico , Luz , Masculino , Potencial da Membrana Mitocondrial/efeitos dos fármacos , Camundongos , Mitocôndrias/efeitos dos fármacos , Nanopartículas/química , Nanopartículas/efeitos da radiação , Compostos Organometálicos/síntese química , Compostos Organometálicos/efeitos da radiação , Compostos Organometálicos/uso terapêutico , Fármacos Fotossensibilizantes/química , Fármacos Fotossensibilizantes/efeitos da radiação , Fármacos Fotossensibilizantes/uso terapêutico , Espécies Reativas de Oxigênio/metabolismo , beta-Ciclodextrinas/síntese química , beta-Ciclodextrinas/efeitos da radiação , beta-Ciclodextrinas/uso terapêutico
14.
ACS Sens ; 6(3): 1138-1146, 2021 03 26.
Artigo em Inglês | MEDLINE | ID: mdl-33503372

RESUMO

Butyrylcholinesterase (BChE) is an essential human cholinesterase relevant to liver conditions and neurodegenerative diseases, which makes it a pivotal biomarker of health. It therefore remains challenging and highly desired to elaborate efficient chemical tools for BChE with simple operations and satisfactory working performance. In this work, a background-free detection strategy was built by virtue of the judicious coupling of a specific BChE-enzymatic reaction and in situ cyclization. High sensitivity with a low limit of detection (LOD) of 0.075 µg/mL could be readily achieved from the blank background and the as-produced emissive indicators, and the specific reaction site contributed to the high selectivity over other bio-species even acetylcholinesterase (AChE). In addition to the multifaceted spectral experiments to verify the sensing mechanism, this work assumed comprehensive studies on the application. The bio-investigation ranged from cells to an organism, declaring a noteworthy prospect in disease diagnosis, especially for Alzheimer's disease (AD), a common neurodegenerative disease with over-expressed BChE. Moreover, its excellent work for inhibition efficacy elucidation was also proved with the accuracy IC50 of tacrine for BChE (8.6 nM), giving rise to an expanded application for trace pesticide determination.


Assuntos
Doenças Neurodegenerativas , Resíduos de Praguicidas , Acetilcolinesterase , Butirilcolinesterase , Inibidores da Colinesterase , Humanos
15.
Talanta ; 221: 121554, 2021 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-33076110

RESUMO

An increased content of reactive oxygen species (ROS) is a primary feature of tumor cells. When the new homeostasis established by cancer cells with a high ROS level is destroyed, this leads to oxidative stress and apoptosis. In this study, a composite nanosystem was designed in which the DNA structure with the functions of miRNA detection and drug delivery is connected to CeO2 nanoclusters that exhibit enzyme-like activity to enable them to load drugs together. In addition, based on the concept of sequential catalysis, we used CeO2 to decompose H2O2 into O2 with low cytotoxicity, which provides raw materials for the photodynamic therapy (PDT) of the Cy5 fluorescent group modified on the DNA. Subsequently, this is transformed into highly cytotoxic free radicals (OH), and we used PDT to further stimulate the therapeutic ability of doxorubicin (DOX) to improve its effectiveness in killing cancer cells. This composite nanosystem can perform fluorescence detection for miRNA-21 in vitro, intracellular fluorescence imaging, and PDT treatment, and can enhance the effect of DOX.


Assuntos
MicroRNAs , Fotoquimioterapia , Cério , DNA/genética , Doxorrubicina/farmacologia , Células HEK293 , Células Hep G2 , Humanos , Peróxido de Hidrogênio , MicroRNAs/genética , Espécies Reativas de Oxigênio
16.
Anal Chim Acta ; 1141: 206-213, 2021 Jan 02.
Artigo em Inglês | MEDLINE | ID: mdl-33248653

RESUMO

Herein, a dual-selective recognition and multi-enhanced surface-enhanced Raman scattering (SERS)-fluorescence dual mode detection platform is designed for the detection of circulating tumor cells (CTCs). The gold nanoflowers (AuNFs) substrate was synthesized and the CTCs were captured on the surface area of AuNFs/ITO substrate by aptamers modified. At the same time, the novel nanoprobe was designed, anti-EpCAM (AE) and trigger DNA were modified onto the surface of gold nanostars (AuNSs) through a PEG linker. The novel nanoprobe identified CTCs through the specific recognition reaction between AE and the cell epithelial adhesion molecule of the CTCs. The dual-recognition cellular mechanism of the aptamers and AE improves selectivity. Then, the complementary sequence (CS) hybridize with aptamers to release the captured CTCs into the culture medium. The number of CTCs released was detected by SERS and fluorescence. The limit of SERS detection was 5 cells/mL with a linear relationship from 5 to 200 cells/mL. The limit of fluorescence detection was 10 cells/mL with a linear relationship from 10 to 200 cells/mL. Thus, the developed CTCs detection platform demonstrates promising applications for clinical diagnosis.


Assuntos
Nanoestruturas , Células Neoplásicas Circulantes , Contagem de Células , Ouro , Humanos , Análise Espectral Raman
17.
J Hazard Mater ; 406: 124749, 2021 03 15.
Artigo em Inglês | MEDLINE | ID: mdl-33333380

RESUMO

Developing effective analytical method for sulfadimethoxine (SDM) detection is highly desirable and vitally crucial for protecting environment safety and human health. Herein, a highly selective and sensitive photoelectrochemical (PEC) aptasensor for accurate detection of SDM was proposed, which employed zinc phthalocyanine/graphitic carbon nitride (ZnPc/CN) nanocomposite as photosensitive material. The ZnPc/CN nanocomposite was constructed by modification of CN nanosheet with visible/near-infrared light responsive photosensitizer ZnPc. The introduction of ZnPc into CN exhibited amplified PEC response, which was 5.7 and 18.3 times than pure ZnPc and CN, attributed to the enhanced light harvesting ability and improved photoelectric conversion efficiency of such nanocomposite. By using ZnPc/CN and sulfadimethoxine (SDM) aptamer as PEC response material and specific probe, a PEC aptasensor was established for SDM detection. The aptamer was connected to the surface of chitosan/ZnPc/CN/ITO through the formation of phosphoramidate bonds between the amino group of the chitosan and phosphate group of the aptamer at 5' end. The fabricated aptasensor displayed good detection linearity of 0.1 ~ 300 nM and low detection limit of 0.03 nM (S/N = 3) under optimized conditions, and the potential applicability of the PEC aptasensor was confirmed by detecting SDM in milk powder samples.

18.
Anal Chem ; 92(24): 16221-16228, 2020 12 15.
Artigo em Inglês | MEDLINE | ID: mdl-33210902

RESUMO

Homocysteine (Hcy) is one of the important biomarkers of clinical diagnosis, which is closely related to the occurrence and development of many diseases. Current analysis methods have difficulties in detecting Hcy in cells and living organisms. As a powerful technique, fluorescence methods combined the laser confocal imaging technology can achieve real-time visual tracking in cells and in vivo. Herein, we establish a conjugated copolymer-based fluorescence nanosensor (DPA-PFNP-Cu(II)) using the connected 2,7-dibromofluorene and 4,7-bis (2-bromothiophen-5-yl)-2-1-3-benzothiadiazole as the main chain. The competitive coordination between Hcy and Cu(II) allows the fluorescence of the polymer off to on. Finally, the nanosensor is applied for in situ imaging of Hcy levels in the kidney and liver of diabetic mice and is found that Hcy levels were positively correlated with the degree of diabetes. Notably, the depth of tissue penetration of the nanosensor enables Hcy detection of the liver and kidney through in vivo imaging without damage. Two-photon imaging and in vivo imaging achieve consistent results, which correct each other, improving the accuracy of the test result. The present works provide a new imaging technique for studying the occurrence and development of diabetes and screening of new drugs for treatment at the living level.


Assuntos
Diabetes Mellitus Experimental/metabolismo , Corantes Fluorescentes/metabolismo , Homocisteína/metabolismo , Rim/metabolismo , Fígado/metabolismo , Imagem Molecular/métodos , Nanotecnologia/métodos , Animais , Cobre/química , Corantes Fluorescentes/química , Camundongos , Polímeros/química , Tiadiazóis/química
19.
Anal Chim Acta ; 1136: 134-140, 2020 Nov 01.
Artigo em Inglês | MEDLINE | ID: mdl-33081937

RESUMO

In this paper, an effective and accurate ratiometric electrochemiluminescence (ECL) system based on Au-luminol and CdS quantum dots (CdS QDs) as signal probes was constructed for detecting carcinoembryonic antigen (CEA). Polyaniline (PANI) and gold nanoparticles (AuNPs) strongly enhanced the electronic transfer efficiency and the specific area of the modified sensing surface, and improved the detection sensitivity. CdS QDs functionalized DNA strands functioned as cathode ECL emitters, and the aptamer of CEA modified with Au-luminol and quencher cyanine dye (Cy5) fluorophore functioned as anode ECL emitters. After the DNA capture probe combined with CEA aptamer, the negative potential ECL response of the CdS QDs was quenched because of electrochemiluminescence resonance energy transfer (ERET) between the Cy5 fluorophore and CdS QDs. However, the positive potential ECL response of Au-luminol can still be detected. The negative potential ECL response of CdS QDs was recovered, and the positive potential ECL response of Au-luminol decreased after CEA combined with its aptamer to take Cy5 and Au-luminol off the sensing interface. Additionally, the peptide provided effective anti-fouling performance in the detection of complex samples. The ratiometric ECL sensor with anti-fouling ability can sensitively determine the concentration of CEA in human serum.


Assuntos
Técnicas Biossensoriais , Nanopartículas Metálicas , Pontos Quânticos , Antígeno Carcinoembrionário , Técnicas Eletroquímicas , Ouro , Humanos , Limite de Detecção , Luminescência , Medições Luminescentes , Peptídeos
20.
Biochem Biophys Res Commun ; 533(4): 1309-1314, 2020 12 17.
Artigo em Inglês | MEDLINE | ID: mdl-33051059

RESUMO

Spatial learning and memory are typically assessed to evaluate hippocampus-dependent cognitive and memory functions in vivo. Protein phosphorylation and dephosphorylation by kinases and phosphatases play critical roles in spatial learning and memory. Here we report that the Wip1 phosphatase is essential for spatial learning, with knockout mice lacking Wip1 phosphatase exhibiting dysfunctional spatial cognition. Aberrant phosphorylation of the Wip1 substrates p38, ATM, and p53 were observed in the hippocampi of Wip1-/- mice, but only p38 inhibition reversed impairments in long-term potentiation in Wip1-knockout mice. p38 inhibition consistently ameliorated the spatial learning dysfunction caused by Wip1 deficiency. Our results demonstrate that deletion of Wip1 phosphatase impairs hippocampus-dependent spatial learning and memory, with aberrant downstream p38 phosphorylation involved in this process and providing a potential therapeutic target.


Assuntos
Memória , Proteína Fosfatase 2C/fisiologia , Aprendizagem Espacial , Animais , Hipocampo/enzimologia , Hipocampo/fisiologia , Potenciação de Longa Duração , Masculino , Camundongos Knockout , Teste do Labirinto Aquático de Morris , Fosforilação , Proteína Fosfatase 2C/genética , Proteínas Quinases p38 Ativadas por Mitógeno/antagonistas & inibidores , Proteínas Quinases p38 Ativadas por Mitógeno/metabolismo
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