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1.
J Appl Microbiol ; 135(5)2024 May 01.
Article in English | MEDLINE | ID: mdl-38658191

ABSTRACT

AIMS: The research aimed to optimize the ultrasound-assisted extraction of secondary metabolites and the antibacterial activity of the plant species Geranium robertianum. The phytochemical profiles of the optimized extracts, as well as their antibacterial and synergistic activity with an antibiotic and their potential mechanisms of action and cytotoxicity, were examined. METHODS AND RESULTS: Response Surface Methodology was used to optimize extraction conditions. Optimized ethanol and acetone extracts were tested via microdilution, checkerboard, time-kill kinetics, and cell membrane permeability methods. The extracts displayed broad antibacterial activity with minimum inhibitory concentrations ranging from 1.25 to 20 mg ml-1. In addition, the extract synergistically reacted with gentamicin against gentamicin-resistant strains of Escherichia coli and Staphylococcus aureus, enhancing the efficacy of the antibiotic up to 32-fold. The extracts demonstrated strain-dependent bactericidal activity in a 24-h time interval. They increase the permeability of the cell membrane, thus disrupting its normal functioning. The cytotoxic concentration (CC50) on human keratinocytes was 1771.24 ± 5.78 µg ml-1 for ethanol extract, and 958.01 ± 6.14 µg ml-1 for acetone extract. Kaempferol, ellagic acid, quercetin, and rutin were recognized as the main components in both extracts. CONCLUSIONS: The findings of this study indicate that the extracts of G. robertianum can be considered as potential natural antibacterial agents in the control of microorganisms.


Subject(s)
Anti-Bacterial Agents , Escherichia coli , Geranium , Microbial Sensitivity Tests , Plant Extracts , Staphylococcus aureus , Anti-Bacterial Agents/pharmacology , Geranium/chemistry , Plant Extracts/pharmacology , Staphylococcus aureus/drug effects , Humans , Escherichia coli/drug effects , Gentamicins/pharmacology , Keratinocytes/drug effects
2.
RSC Adv ; 14(7): 4591-4606, 2024 Jan 31.
Article in English | MEDLINE | ID: mdl-38318620

ABSTRACT

This research explores the synthesis, characterization, and biological activities of silver nanoparticles (AgNPs) derived from acetone (AgNPs-acetone) and aqueous (AgNPs-H2O) extracts of Agrimonia eupatoria. The nanoparticles exhibit isometric morphology and uniform size distribution, as elucidated through Transmission Electron Microscopy (TEM) and high-resolution TEM (HRTEM) analyses. The utilization of Scanning Transmission Microscopy (STEM) with High-Angle Annular Dark-Field (HAADF) imaging and energy dispersive spectrometry (EDS) confirms the crystalline nature of AgNPs. Fourier Transform Infrared (FTIR) analysis reveals identical functional groups in the plant extracts and their corresponding AgNPs, suggesting the involvement of phytochemicals in the reduction of silver ions. Spectrophotometric monitoring of the synthesis process, influenced by various parameters, provides insights into the kinetics and optimal conditions for AgNP formation. The antioxidant activities of the plant extracts and synthesized AgNPs are evaluated through DPPH and ABTS methods, highlighting AgNPs-acetone as a potent antioxidant. Third-instar larvae exposed to the extracts have differential effects on DNA damage, with the acetone extract demonstrating antigenotoxic properties. Similarly, biosynthesized AgNPs-acetone displays antigenotoxic effects against EMS-induced DNA damage. The genotoxic effect of water extract and AgNPs-acetone was dose-dependent. Hemolytic potential is assessed on rat erythrocytes, revealing that low concentrations of AgNPs-acetone and AgNPs-H2O had a nontoxic effect on erythrocytes. Cytotoxicity assays demonstrate time-dependent and dose-dependent effects, with AgNPs-acetone exhibiting superior cytotoxicity. Proapoptotic activity is confirmed through apoptosis induction, emphasizing the potential therapeutic applications of AgNPs. The antimicrobial activity of AgNPs reveals concentration-dependent effects. AgNPs-H2O display better antibacterial activity, while antifungal activities are comparable between the two nanoparticle types.

4.
Antioxidants (Basel) ; 12(12)2023 Dec 01.
Article in English | MEDLINE | ID: mdl-38136190

ABSTRACT

In this study, green synthesis of two derivatives of coumarin-hydroxybenzohydrazide, (E)-2,4-dioxo-3-(1-(2-(2,3,4-trihydroxybenzoyl)hydrazyl)ethylidene)-chroman-7-yl acetate (C-HB1), and (E)-2,4-dioxo-3-(1-(2-(3,4,5-trihydroxybenzoyl)hydrazyl)ethylidene)chroman-7-yl acetate (C-HB2) is reported. Using vinegar and ethanol as a catalyst and solvent, the reactions were carried out between 3-acetyl-4-hydroxy-coumarin acetate and corresponding trihydroxybenzoyl hydrazide. The antioxidant potential of these compounds was investigated using the DPPH and ABTS assays, as well as the FRAP test. The obtained results reveal that even at very low concentrations, these compounds show excellent radical scavenging potential. The IC50 values for C-HB1 and C-HB2 in relation to the DPPH radical are 6.4 and 2.5 µM, respectively, while they are 4.5 and 2.0 µM in relation to the ABTS radical. These compounds have antioxidant activity that is comparable to well-known antioxidants such as gallic acid, NDGA, and trolox. These results are in good correlation with theoretical parameters describing these reactions. Moreover, it was found that inhibition of DPPH● follows HAT, while inactivation of ABTS+● follows SET-PT and HAT mechanisms. Additionally, coumarin-hydroxybenzohydrazide derivatives induced moderate cytotoxic activity and show significant potential to modulate redox status in HCT-116 colorectal cancer cells. The cytotoxicity was achieved via their prooxidative activity and ability to induce oxidative stress in cancer cells by increasing O2˙- concentrations, indicated by increased MDA and GSH levels. Thus, ROS manipulation can be a potential target for cancer therapies by coumarins, as cancer cells possess an altered redox balance in comparison to normal cells. According to the ADMET analysis, the compounds investigated show good pharmacokinetic and toxicological profiles similar to vitamin C and gallic acid, which makes them good candidates for application in various fields of industry and medicine.

5.
Int J Gynecol Cancer ; 33(9): 1394-1401, 2023 09 04.
Article in English | MEDLINE | ID: mdl-37541686

ABSTRACT

OBJECTIVES: MicroRNAs (miRNAs) have emerged as biomarkers that showed strong diagnostic potential in various diseases, including cancer. This study aimed to estimate the expression and diagnostic potential of miRNAs (miR-200a, miR-21, miR-210, miR-126, and miR-130a) in endometrial cancer samples. The DICER1 and AGO2 genes were also analysed. METHODS: The expression of miRNAs, DICER1, and AGO2 was quantified using the quantitative real-time PCR method in 40 tissue samples with early-stage endometrial cancer and 16 normal controls. RESULTS: All tested miRNAs showed significantly higher expression in endometrial cancer compared with the control group, while DICER1 was significantly downregulated. The expression levels of miR-200a, miR-21, and miR-210 were negatively correlated with DICER1 expression. Individually, miR-200a, miR-21, miR-210, and DICER1 showed the best diagnostic performance in distinguishing patients with endometrial cancer from normal controls, whereas a combination of all biomarkers resulted in an even higher area under the curve. CONCLUSIONS: Our study showed that a panel of selected biomarkers (miR-200a, miR-21, miR-210, miR-126, miR-130a, DICER1, and AGO2) may be candidates for the detection of early-stage endometrial cancer.


Subject(s)
Endometrial Neoplasms , MicroRNAs , Female , Humans , MicroRNAs/genetics , MicroRNAs/metabolism , Endometrial Neoplasms/diagnosis , Endometrial Neoplasms/genetics , Endometrial Neoplasms/metabolism , Endometrium/metabolism , Biomarkers, Tumor/genetics , Biomarkers, Tumor/metabolism , Ribonuclease III/genetics , Ribonuclease III/metabolism , DEAD-box RNA Helicases/genetics , DEAD-box RNA Helicases/metabolism
6.
Eur J Pharmacol ; 939: 175456, 2023 Jan 15.
Article in English | MEDLINE | ID: mdl-36528070

ABSTRACT

Breast cancer as most often women's cancer is the second cause of mortality worldwide. Research interest increased in testing non-standard drugs to suppress breast cancer progression and become significant supplements in anticancer therapy. The anti-obesity drug Orlistat showed significant ability for modulation of cancer cell metabolism via antiproliferative, proapoptotic, antiangiogenic, antimetastatic, and hypolipidemic effects. The anticancer potential of Orlistat was evaluated by cytotoxicity (MTT assay), type of cell death (AO/EB double staining), determination of redox status parameters (superoxide, hydrogen peroxide, lipid peroxidation, reduced glutathione), and total lipid levels with colorimetric methods, as well on angiogenesis-related (VEGF, MMP-9, CXCR4/CXCL12) and fatty acid synthesis-related (ACLY, ACC, FASN) parameters on gene and protein levels (immunocytochemistry and qPCR). Based on obtained results Orlistat induces significant cytotoxic, proapoptotic, and anti-angiogenic effects in MDA-MB-231, MDA-MB-468 and MCF-7 breast cancer cells, without significant cytotoxic effects on normal MRC-5 cells. It decreased total lipid levels and changed redox status parameters and cancer cell metabolism via suppression of genes and proteins involved and fatty acid synthesis. Based on showed, Orlistat may be an important supplement in antiangiogenic therapy against breast cancer with no side effects on normal cells, making it a good candidate for future clinical trials.


Subject(s)
Breast Neoplasms , Lactones , Female , Humans , Orlistat/pharmacology , Orlistat/therapeutic use , Lactones/pharmacology , Breast Neoplasms/pathology , Cell Line, Tumor , Fatty Acids/metabolism , Lipids , Apoptosis , Cell Proliferation
7.
J Pharm Sci ; 111(12): 3215-3223, 2022 12.
Article in English | MEDLINE | ID: mdl-36162493

ABSTRACT

Due to their promising effects, gold(III) complexes recently drew increasing attention in the design of new metal-based anticancer therapeutics. Two gold(III) complexes, square-planar [Au(DPP)Cl2]+ - Complex 1 and distorted square-pyramidal [Au(DMP)Cl3] - Complex 2 (where DPP=4,7-diphenyl-1,10-phenanthroline and DMP=2,9-dimethyl-1,10-phenanthroline) were previously synthetized, described and approved as complexes with pronounced cytotoxic effects on colorectal HCT-116 and breast MDA-MB-231 cancer cells. This study investigated the type of cell death by AO/EB double staining, and identification of possible targets responsible for their cytotoxicity, monitored by immunofluorescence and qPCR methods. Both complexes induced apoptosis in all applied concentrations. In the HCT-116 cells apoptosis was activated by external apoptotic pathway, via increase of Fas receptor protein expression and Caspase 8 gene expression. Also, the mitochondrial pathway was triggered by affecting the Bcl-2 members of regulatory proteins and increased caspase 9 protein expression. In MDA-MB-231 cells, apoptosis was initiated from the mitochondria, due to disbalance between expressions of pro- and anti-apoptotic Bcl-2 family members and caspase 9 activation. Complex 1 shows better activity compared to Complex 2, which is in accordance with its structural characteristics. The results deal weighty data about proapoptotic activity of gold(III) complexes and highlighted potential targets for cancer therapy.


Subject(s)
Breast Neoplasms , Colorectal Neoplasms , Humans , Female , Phenanthrolines/pharmacology , Phenanthrolines/chemistry , Caspase 9/pharmacology , Gold/pharmacology , Gold/chemistry , Breast Neoplasms/drug therapy , Cell Line, Tumor , Apoptosis , Proto-Oncogene Proteins c-bcl-2/pharmacology , Ligands , Colorectal Neoplasms/drug therapy
8.
Article in English | MEDLINE | ID: mdl-36142096

ABSTRACT

Enterobacteriaceae are widely present in many environments related to humans, including the human body and the food that they consume, from both plant or animal origin. Hence, they are considered relevant members of the gastrointestinal tract microbiota. On the other hand, these bacteria are also recognized as putative pathogens, able to impair human health and, in food, they are considered indicators for the microbiological quality and hygiene status of a production process. Nevertheless, beneficial properties have also been associated with Enterobacteriaceae, such as the ability to synthesize peptides and proteins, which can have a role in the structure of microbial communities. Among these antimicrobial molecules, those with higher molecular mass are called colicins, while those with lower molecular mass are named microcins. In recent years, some studies show an emphasis on molecules that can help control the development of pathogens. However, not enough data are available on this subject, especially related to microcins. Hence, this review gathers and summarizes current knowledge on colicins and microcins, potential usage in the treatment of pathogen-associated diseases and cancer, as well as putative applications in food biotechnology.


Subject(s)
Anti-Infective Agents , Colicins , Animals , Bacteriocins , Colicins/chemistry , Colicins/metabolism , Colicins/pharmacology , Enterobacteriaceae , Humans , Peptides
9.
Eur J Pharmacol ; 910: 174466, 2021 Nov 05.
Article in English | MEDLINE | ID: mdl-34481879

ABSTRACT

This study evaluated the potential of antitumor activity of snake venom from Vipera ammodytes and L-amino acid oxidase from Crotalus adamanteus on different colorectal cancer cell lines through determination of cytotoxic activity by MTT assay, pro-apoptotic activity by acridine orange/ethidium bromide staining, and concentrations of redox status parameters (superoxide, reduced glutathione, lipid peroxidation) by colorimetric methods. The expression of genes involved in the biotransformation process and metabolite efflux was determined by qPCR method, while protein expression of glutathione synthetase and P-glycoprotein were analysed by immunocytochemistry. The analysis of cell death shows that snake venom dominantly leads cells to necrosis. Induction of apoptosis by L-amino acid oxidase was in correlation with oxidative disbalance in cancer cells. Gene expression profile of membrane transporters and CYP genes were different in each cell line and in correlation with their sensitivity of treatment. Our results show that L-amino acid oxidase from snake venom is a potent cytotoxic substance with pronounced pro-apoptotic activity. The inhibition of P-glycoprotein suggests that L-amino acid oxidase is a good substance for furter research of antitumor effect, with unexpressed potential for occurrence of drug resistance in vitro.


Subject(s)
Biological Products/pharmacology , Colonic Neoplasms/drug therapy , L-Amino Acid Oxidase/pharmacology , Viper Venoms/enzymology , Animals , Apoptosis/drug effects , Biological Products/isolation & purification , Biological Products/therapeutic use , Biotransformation/drug effects , Biotransformation/genetics , Cell Line, Tumor , Colonic Neoplasms/genetics , Colonic Neoplasms/pathology , Crotalus , Drug Screening Assays, Antitumor , Gene Expression Regulation, Neoplastic/drug effects , Humans , L-Amino Acid Oxidase/isolation & purification , L-Amino Acid Oxidase/therapeutic use
10.
Article in English | MEDLINE | ID: mdl-32265044

ABSTRACT

A large number of species belonging to the genus Teucrium are used in pharmacy and traditional medicine for the treatment of different diseases. This study aimed to evaluate the polyphenolic composition as well as genotoxic and cytotoxic effects of methanolic extracts from T. arduini and T. flavum, two native species found in Montenegro. We determined the total phenolic and flavonoid contents of these plants using spectrophotometric methods; the qualitative content of polyphenolic compounds was investigated by high-performance liquid chromatography (HPLC). Genotoxicity in cultured human lymphocytes was measured in the cytokinesis-block micronucleus assay (CBMN) and comet assay in the range between 125 and 1000 µg/mL. Cytotoxicity was assessed by the MTT viability assay in normal human MRC-5 fibroblasts and MDA-MB-231 breast carcinoma cells. The content of total phenolics and flavonoids in T. arduini extract was higher than in T. flavum (200.35 mg GA/g vs. 171.08 mg GA/g; 96.32 mg RU/g vs. 78.14 mg RU/g). The polyphenolic composition of both extracts was qualitatively similar and eight phenol compounds were identified. The most commonly present phenol was caffeic acid and among four flavonoids, the most common was quercetin. Both plant extracts were genotoxic in both the CBMN and comet assays at concentrations of 250, 500 and 1000 µg/mL. After 72 h of exposure, the extracts of T. arduini and T. flavum were found to induce cytotoxicity in MRC-5 fibroblasts but not in MDA-MB-231 breast cancer cells. The results suggest that the constituents of both plant species are genotoxic and cytotoxic, therefore these extracts warrant additional evaluation to be safely applied in humans.


Subject(s)
Flavonoids/toxicity , Mutagens/toxicity , Polyphenols/toxicity , Teucrium/chemistry , Cell Line , Cell Line, Tumor , Cell Survival/drug effects , Comet Assay , Dose-Response Relationship, Drug , Epithelial Cells/drug effects , Epithelial Cells/pathology , Fibroblasts/cytology , Fibroblasts/drug effects , Flavonoids/isolation & purification , Humans , Methanol/chemistry , Micronucleus Tests , Montenegro , Mutagens/isolation & purification , Organ Specificity , Plant Extracts/chemistry , Plants, Medicinal , Polyphenols/isolation & purification , Solvents/chemistry
11.
Anim Biotechnol ; 31(3): 195-202, 2020 Jun.
Article in English | MEDLINE | ID: mdl-30795724

ABSTRACT

Insect silk has been widely studied for its application in regenerative medicine. However, the data about Plodia interpunctella silk as a biomaterial and its anticancer properties are insufficient. Thus, the aim of this study was to investigate native silk as a substrate for growing normal human fibroblasts MRC-5, and test potential cytotoxic effects of the two silk extracts (with DMSO and Trypsin for sericin isolation) on HCT-116 colorectal carcinoma cells and MRC-5 fibroblasts as a control. Fifth-instar larval silk, collected for 15 and 30 days, was used for testing of proliferation and adhesion of MRC-5, 24 h and 72 h after seeding. Light- and fluorescence-microscope showed cell adhesion and spread on silk, as well as enhanced number of cells after 72 compared to 24 h and nonsignificant percentage of apoptotic cells on the silk. Although insoluble, P. interpunctella silk showed remarkable cytotoxic activity on HCT-116 cells, without significant cytotoxity on normal fibroblasts after 24 h and weak effects after 72 h. This study provides significant information about P. interpunctella silk as a potential biomaterial and shows the presence of some active constituents with anticancer properties, thus pointing to the possibility for exploitation of this worldwide pest insect in biomedical application.


Subject(s)
Antineoplastic Agents , Biocompatible Materials , Silk , Animals , Antineoplastic Agents/chemistry , Antineoplastic Agents/pharmacology , Apoptosis/drug effects , Biocompatible Materials/chemistry , Biocompatible Materials/pharmacology , Cell Adhesion/drug effects , Cell Line , Cell Survival/drug effects , Fibroblasts/cytology , Fibroblasts/drug effects , HCT116 Cells , Humans , Moths , Sericins , Silk/chemistry , Silk/pharmacology
12.
J Ethnopharmacol ; 240: 111951, 2019 Aug 10.
Article in English | MEDLINE | ID: mdl-31085226

ABSTRACT

ETHNOPHARMACOLOGICAL RELEVANCE: Teucrum chamaedrys L. is one of the known medicinal plants, useful for treatment of various health problems, especially digestive. In this study, we investigated methanol, ethyl-acetate and acetone extracts of T. chamaedrys in respect to their anticancer properties in SW480 colorectal cancer cells. MATERIALS AND METHODS: Cytotoxicity and proapoptotic potential were assessed by MTT cell viability assay and AO/EB double staining. Molecular mechanisms of induced apoptosis were determined by monitoring Fas receptor protein expression through immunofluorescence, Caspase 8 and 9 activity, as well as concentrations of O2.- spectrophotometrically. Additionally, mRNA expression of biotransformation enzymes (CYP1A1, CYP1B1, GSTP1) and membrane transporters (MRP1 and MRP2) involved in drug resistance were investigated by qPCR method. Qualitative analysis of individual phenolic compounds was performed by reversed phase HPLC-MS analysis. RESULTS: Methanol extract shows the best cytotoxicity and selectivity compared to ethyl-acetate and acetone extracts, mainly causing apoptosis of SW480 cells, without affecting normal HaCaT keratinocytes. The increased expression of Fas receptor protein and caspase 8 activity indicate that the death receptor-mediated pathway plays a crucial role in the observed apoptosis. The increased caspase 9 activity and O2.- concentration suggest that mitochondria are also involved in the apoptosis. T. chamaedrys methanol extract inhibits mRNA expression of CYP1A1, CYP1B1, GSTP1, MRP1 and MRP2 in SW480 cells. CONCLUSIONS: Induction of apoptosis and inhibition of CYP1A1, CYP1B1, GSTP1, MRP1 and MRP2 mRNA expression implies that T. chamaedrys can serve as a valuable source of bioactive compounds as dietary supplements or selective anticancer agents, with the ability to induce apoptosis and modulate drug resistance in colorectal cancer cells.


Subject(s)
Antineoplastic Agents, Phytogenic/pharmacology , Plant Extracts/pharmacology , Teucrium , Apoptosis/drug effects , Biotransformation/drug effects , Cell Line , Cell Survival/drug effects , Colorectal Neoplasms/drug therapy , Colorectal Neoplasms/genetics , Colorectal Neoplasms/metabolism , Cytochrome P-450 CYP1A1/genetics , Cytochrome P-450 CYP1B1/genetics , Flowers , Gene Expression Regulation, Neoplastic/drug effects , Glutathione S-Transferase pi/genetics , Humans , Multidrug Resistance-Associated Protein 2 , Multidrug Resistance-Associated Proteins/genetics
13.
Bioelectrochemistry ; 2016 Oct 22.
Article in English | MEDLINE | ID: mdl-28029459

ABSTRACT

PURPOSE: To study the effects of electroporation on different cell lines. MATERIAL: The effects of electroporation on human breast cancer (MDA-MB-231), human colon cancer (SW-480 and HCT-116), human fibroblast cell line (MRC-5), primary human aortic smooth muscle cells (hAoSMC) and human umbilical vein endothelial cells (HUVEC) were studied. Real-time technology was used for cell viability monitoring. Acridine orange/ethidium bromide assay was applied for cell death type determination. A numerical model of electroporation has been proposed. RESULTS: Electroporation induced inhibition of cell viability on dose (voltage) dependent way. The electroporation treatment 375-437.5Vcm-1 caused irreversible electroporation of cancer cells and reversible electroporation of healthy cells. The application of lower voltage rating (250Vcm-1) led to apoptosis as the predominant type of cell death, whereas the use of higher voltage (500Vcm-1) mainly caused necrosis. CONCLUSION: Electroporation represents a promising method in cancer treatment. Different cancer cell lines had different response to the identical electroporation treatment. Electroporation 375-437.5Vcm-1 selectively caused permanent damage of cancer cells (SW-480), while healthy cells (MRC-5, hAoSM and HUVEC) recovered after 72h. The type of cell death is dependent of electroporation conditions. The proposed numerical model is useful for the analysis of phenomena related to electroporation treatment.

14.
Anal Chem ; 88(17): 8385-9, 2016 09 06.
Article in English | MEDLINE | ID: mdl-27529794

ABSTRACT

Slow off-rate modified aptamers (SOMAmers) are attractive protein recognition reagents due to their high binding affinities, stable chemical structures, easy production, and established selection process. Here, biotinylated SOMAmer reagents were incorporated into single molecule array (Simoa)-based assays in place of traditional detection antibodies for six cytokine targets. Optimization and validation were conducted for TNF-α as a demonstration using a capture antibody/detection-SOMAmer detection scheme to highlight the performance of this approach. The optimized assay has a broad dynamic range (>4 log10 units) and an ultralow detection limit of 0.67 fM (0.012 pg/mL). These results show comparable sensitivity to our antibody pair-based Simoa assays, and tens to thousands-fold enhancement in sensitivity compared with conventional ELISAs. High recovery percentages were observed in a spike-recovery test using human sera, demonstrating the feasibility of this novel Simoa assay in detecting TNF-α in clinically relevant samples. Detection SOMAmers were also used to detect other cytokines, such as IFN-γ, IL-1ß, IL-2, IL-6, and IL-10, in human samples. Although not yet demonstrated, in principle it should be possible to eventually replace both the capture and detector antibodies with corresponding SOMAmer pairs in sandwich immunoassays. The combination of the ultrasensitive Simoa platform with the higher reliability of SOMAmer binding reagents will greatly benefit both biomarker discovery and disease diagnostic fields.


Subject(s)
Aptamers, Nucleotide/chemistry , Cytokines/blood , Indicators and Reagents/chemistry , Antibodies/immunology , Cytokines/immunology , Enzyme-Linked Immunosorbent Assay , Humans , Kinetics
15.
Anal Chem ; 88(12): 6585-92, 2016 06 21.
Article in English | MEDLINE | ID: mdl-27213503

ABSTRACT

The combination of enzymes, as recognition elements for specific analytes, and of electrogenerated chemiluminescence (ECL) as a readout method has proven to be a valuable strategy for sensitive and specific analytical detection. However, ECL is intrinsically a 2D process which could potentially limit the analysis of inhomogeneous samples. Here, we show how a bulk ECL signal, generated by thousands of carbon microbeads remotely addressed via bipolar electrochemistry, are implemented as a powerful tool for the concomitant ECL sensing and imaging of two enzymatic substrates. We selected two enzymes (glucose dehydrogenase and choline oxidase) that react with their respective model substrates and produce in situ chemical species (ß-nicotinamide adenine dinucleotide (NADH) and H2O2) acting as coreactants for the ECL emission of different luminophores ([Ru(bpy)3](2+) at λ = 620 nm and luminol at λ = 425 nm, respectively). Both enzymes are spatially separated in the same capillary. We demonstrate thus the simultaneous quantitative determination of both glucose and choline over a wide concentration range. The originality of this remote approach is to provide a global chemical view through one single ECL image of inhomogeneous samples such as a biochemical concentration gradient in a capillary configuration. Finally, we report the first proof-of-concept of dual biosensing based on this bulk ECL method for the simultaneous imaging of both enzymatic analytes at distinct wavelengths.


Subject(s)
Biosensing Techniques/methods , Choline/analysis , Glucose/analysis , Luminescent Measurements/methods , Alcohol Oxidoreductases/chemistry , Glucose 1-Dehydrogenase/chemistry , Luminol/chemistry , Models, Molecular
16.
Analyst ; 140(18): 6277-82, 2015 Sep 21.
Article in English | MEDLINE | ID: mdl-26270328

ABSTRACT

Concentrations of cytokines in bodily fluids reflect the physiological or pathological state of the patient and can be used for prognosis, disease diagnosis or for monitoring therapeutic efficacy. However, in the bodily fluids of healthy or sub-healthy individuals, many cytokines are present at concentrations that are near or below the detection limits of current methods. Here we selected antibody pairs to be employed in the single molecule array (Simoa) assay for ten cytokines including GM-CSF, TNF-α, IFN-γ, IL-1ß, IL-2, IL-4, IL-5, IL-6, IL-7, and IL-10. The limits of detection (LODs) obtained were as low as 90 aM-6 fM. These assays allow detection of cytokines in healthy human serum samples at levels significantly below the detection limits of conventional ELISA assays. We provide detailed antibody pair information as well as the concentration profiles of ten cytokines in healthy human serum to serve as reference data for further ultrasensitive immunoassay development and future clinical applications.


Subject(s)
Antibodies/immunology , Blood Chemical Analysis/instrumentation , Cytokines/blood , Immunoassay/instrumentation , Cytokines/immunology , Humans , Limit of Detection
17.
J Am Chem Soc ; 136(39): 13709-14, 2014 Oct 01.
Article in English | MEDLINE | ID: mdl-25198059

ABSTRACT

The delivery of exogenous agents can enable noninvasive disease monitoring, but existing low-dose approaches require complex infrastructure. In this paper, we describe a microdose-scale injectable formulation of nanoparticles that interrogate the activity of thrombin, a key regulator of clotting, and produce urinary reporters of disease state. We establish a customized single molecule detection assay that enables urinary discrimination of thromboembolic disease in mice using doses of the nanoparticulate diagnostic agents that fall under regulatory guidelines for "microdosing."


Subject(s)
Nanoparticles , Thrombin , Venous Thromboembolism/diagnosis , Animals , Biomarkers/urine , Dose-Response Relationship, Drug , Female , Mice , Nanoparticles/administration & dosage , Nanoparticles/chemistry , Thrombin/administration & dosage , Thrombin/chemistry
18.
Chem Commun (Camb) ; 47(32): 9125-7, 2011 Aug 28.
Article in English | MEDLINE | ID: mdl-21738936

ABSTRACT

Photoinitiated polymerisation is efficiently and rapidly carried out to immobilise ultrathin electrochemiluminescent redox hydrogel films. Microscale patterns are fabricated on an electrode surface by a simple photolithographic procedure and revealed by ECL imaging.


Subject(s)
Methylgalactosides/chemistry , Electrochemical Techniques , Luminescence , Oxidation-Reduction , Photochemical Processes , Polymerization , Surface Properties
19.
Bioelectrochemistry ; 82(1): 63-8, 2011 Aug.
Article in English | MEDLINE | ID: mdl-21733762

ABSTRACT

In this work, we report a new sensing approach based on electrogenerated chemiluminescence (ECL) in an electrodeposited redox hydrogel using glucose dehydrogenase as a model system. The ECL-hydrogel films were electrodeposited by potential cycling of a PBS solution containing [poly(4-vinylpyridine)Ru(2,2'-bipyridine)(2)Cl(-)](+/2+). The film was easily prepared in a rapid, reproducible and well-controlled one-step procedure. The deposited hydrogel film is permeable to water-soluble chemicals and biochemicals, like enzyme substrates and coenzymes. Electrochemistry and ECL of NADH were studied at the level of the hydrogel film. Results indicate that ECL emission occurs at a relatively low anodic potential compared to the classical Ru(bipy)(3)(2+) complex. This is an important advantage since the measurements performed with the ECL hydrogel are thus less sensitive to interfering species. An ECL oxidative-reductive mechanism is presented for the ECL-hydrogel. Then we showed that the intensity of the ECL of NADH produced by the enzymatic activity varies with the enzyme substrate concentration. Such sensing approach combines enzymatic selectivity with the ECL advantages at low oxidation potential.


Subject(s)
Electrochemical Techniques/methods , Glucose 1-Dehydrogenase/metabolism , Glucose/analysis , Hydrogel, Polyethylene Glycol Dimethacrylate/chemistry , Luminescent Measurements/methods , NAD/metabolism , Thermoplasma/enzymology , Glucose/metabolism , Luminescence , Oxidation-Reduction , Sensitivity and Specificity
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