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1.
ACS Meas Sci Au ; 4(1): 81-91, 2024 Feb 21.
Article in English | MEDLINE | ID: mdl-38404497

ABSTRACT

This research delves into the development and optimization of MXene nanosheet-based paper electrodes, emphasizing their adaptability in green electronics and diverse applications. Xuan paper, a cellulose-based material, was identified as an ideal substrate for its mechanical attributes and capacity to accommodate MXene, further yielding outstanding electrical conductivity. The MXene paper electrode demonstrated consistent performance under various conditions, showing its potential in the field of wearable electronics and medical devices. Notably, its impressive electrothermal capabilities and environmentally conscious decomposition mechanism make it a promising candidate for future green electronic applications. Overall, this study underscores the electrode's harmonization of performance and environmental sustainability, paving the way for its integration into futuristic electronic solutions.

2.
Biosensors (Basel) ; 13(7)2023 Jun 30.
Article in English | MEDLINE | ID: mdl-37504094

ABSTRACT

Bacteria are similar to social organisms that engage in critical interactions with one another, forming spatially structured communities. Despite extensive research on the composition, structure, and communication of bacteria, the mechanisms behind their interactions and biofilm formation are not yet fully understood. To address this issue, scanning probe techniques such as atomic force microscopy (AFM), scanning electrochemical microscopy (SECM), scanning electrochemical cell microscopy (SECCM), and scanning ion-conductance microscopy (SICM) have been utilized to analyze bacteria. This review article focuses on summarizing the use of electrochemical scanning probes for investigating bacteria, including analysis of electroactive metabolites, enzymes, oxygen consumption, ion concentrations, pH values, biofilms, and quorum sensing molecules to provide a better understanding of bacterial interactions and communication. SECM has been combined with other techniques, such as AFM, inverted optical microscopy, SICM, and fluorescence microscopy. This allows a comprehensive study of the surfaces of bacteria while also providing more information on their metabolic activity. In general, the use of scanning probes for the detection of bacteria has shown great promise and has the potential to provide a powerful tool for the study of bacterial physiology and the detection of bacterial infections.


Subject(s)
Biofilms , Quorum Sensing , Microscopy, Atomic Force/methods , Microscopy, Fluorescence , Bacteria/chemistry , Ions
3.
J Plast Reconstr Aesthet Surg ; 82: 12-20, 2023 07.
Article in English | MEDLINE | ID: mdl-37148805

ABSTRACT

BACKGROUND: Craniofacial bones are the most commonly involved site of Langerhans cell histiocytosis (LCH). The main purpose of this study was to clarify the relation between subsites of craniofacial bone and clinical presentation, treatment modalities, outcomes, and permanent consequences (PCs) in patients with LCH. METHODS: Forty-four patients diagnosed with LCH involving the craniofacial region presenting at a single medical center during 2001-2019 were collected and divided into four groups: single system with unifocal bone lesion (SS-LCH, UFB); single system with multifocal bone lesions (SS-LCH, MFB); multisystem without risk organ involvement (MS-LCH, RO-); and multisystem with risk organ involvement (MS-LCH, RO+). Data including demographics, clinical presentation, treatments, outcomes, and the development of PC were retrospectively reviewed. RESULTS: Temporal bone (66.7% versus 7.7%, p = 0.001), occipital bone (44.4% versus 7.7%, p = 0.022), and sphenoid bone (33.3% versus 3.8%, p = 0.041) involvement were more common in SS-LCH, MFB than they were in SS-LCH, UFB. No difference of reactivation rate was noted among the four groups. The most common PC is diabetes insipidus (DI), reported in 9 of the 16 (56.25%) patients with PC. The single system group was reported with the lowest incidence of DI (7.7%, p = 0.035). The reactivation rate was also higher in patients with PC (33.3% versus 4.0%, p = 0.021) or DI (62.5% versus 3.1%, p < 0.001). CONCLUSION: An increased risk of multifocal or multisystem lesions was associated with temporal bone, occipital bone, sphenoid bone, maxillary bone, eye, ear, and oral involvement, which may indicate poor outcomes. Longer follow-up may be indicated if there is the presence of PC or DI due to the high risk of reactivation. Therefore, multidisciplinary evaluation and treatment according to risk stratification are vital for patients diagnosed with LCH involving the craniofacial region.


Subject(s)
Histiocytosis, Langerhans-Cell , Humans , Retrospective Studies , Histiocytosis, Langerhans-Cell/therapy , Histiocytosis, Langerhans-Cell/complications , Histiocytosis, Langerhans-Cell/diagnosis , Temporal Bone
4.
Gynecol Minim Invasive Ther ; 12(1): 51-54, 2023.
Article in English | MEDLINE | ID: mdl-37025437

ABSTRACT

When obstructive lesions from the uterus or ovaries are suspected, patients with hydronephrosis are usually referred to a gynecologist. Here, a case of suspected endometriosis-related hydroureteronephrosis is reported. A 43-year-old woman with hydronephrosis was found to have a left distal periureteral tumor on the computerized tomography scan. Before the operation, the hydroureteronephrosis was suspected caused by the obstruction of ureter, related with ureteral endometriosis; however, the postoperative pathology revealed the diagnosis of retroperitoneal well-differentiated liposarcoma. When female patients have hydronephrosis, gynecologic causes should be considered. Both benign and malignant causes are needed to include when making differential diagnosis. Therefore, robot-assisted surgery is a feasible option because of its lower morbidity rate and more precise dissection of soft tissue than laparotomy in both benign and malignant retroperitoneal tumors.

5.
Nanotechnology ; 34(16)2023 Feb 06.
Article in English | MEDLINE | ID: mdl-36657162

ABSTRACT

Staphylococcus aureus (S. aureus)forms biofilm that causes periprosthetic joint infections and osteomyelitis (OM) which are the intractable health problems in clinics. The silver-containing nanoparticles (AgNPs) are antibacterial nanomaterials with less cytotoxicity than the classic Ag compounds. Likewise, gold nanoparticles (AuNPs) have also been demonstrated as excellent nanomaterials for medical applications. Previous studies have showed that both AgNPs and AuNPs have anti-microbial or anti-inflammatory properties. We have developed a novel green chemistry that could generate the AuAg nanocomposites, through the reduction of tannic acid (TNA). The bioactivity of the nanocomposites was investigated inS. aureusbiofilm-exposed human osteoblast cells (hFOB1.19). The current synthesis method is a simple, low-cost, eco-friendly, and green chemistry approach. Our results showed that the AuAg nanocomposites were biocompatible with low cell toxicity, and did not induce cell apoptosis nor necrosis in hFOB1.19 cells. Moreover, AuAg nanocomposites could effectively inhibited the accumulation of reactive oxygen species (ROS) in mitochondria and in rest of cellular compartments after exposing to bacterial biofilm (by reducing 0.78, 0.77-fold in the cell and mitochondria, respectively). AuAg nanocomposites also suppressed ROS-triggered inflammatory protein expression via MAPKs and Akt pathways. The current data suggest that AuAg nanocomposites have the potential to be a good therapeutic agent in treating inflammation in bacteria-infected bone diseases.


Subject(s)
Metal Nanoparticles , Nanocomposites , Humans , Gold/pharmacology , Metal Nanoparticles/chemistry , Staphylococcus aureus , Reactive Oxygen Species/metabolism , Anti-Bacterial Agents/pharmacology , Anti-Bacterial Agents/chemistry , Bacteria , Nanocomposites/chemistry , Biofilms , Inflammation/drug therapy , Microbial Sensitivity Tests
6.
ACS Omega ; 7(46): 42233-42241, 2022 Nov 22.
Article in English | MEDLINE | ID: mdl-36440160

ABSTRACT

In this work, we develop a wireless sensor-integrated face mask using Au@SnO2 nanoparticle-modified conductive fibers based on augmented reality (AR) technology. AR technology enables the overlay of real objects and environments with virtual 3D objects and allows virtual interactions with real objects to create desired meanings. With the help of the AR system, the size of the mask could be precisely estimated and then manufactured using 3D printing technology. The body temperature sensor and respiratory sensor were integrated into the mask so that vital parameters of the human body could be continuously monitored without removing the personal protective equipment. Furthermore, the outer part of the mask consists of conductive fabric modified with Au@SnO2 core-shell nanoparticle additives, which enhanced the filtration efficiency of airborne aerosols. A significant improvement in the filtration efficiency of particulate matter 2.5 was observed after applying an external voltage to the conductive textiles. A smartwatch with a heart rate sensor was paired with the mask to display sensor data on the mask through wireless transmission. Therefore, this sensor-integrated mask system with AR technology provides the first line of defense to combat global threats from pathogens and air pollutants.

7.
Biomacromolecules ; 23(7): 2814-2826, 2022 07 11.
Article in English | MEDLINE | ID: mdl-35438970

ABSTRACT

With the advancements in tissue engineering and three-dimensional (3D) bioprinting, physiologically relevant three-dimensional structures with suitable mechanical and bioactive properties that mimic the biological tissue can be designed and fabricated. However, the available bioinks are less than demanded. In this research, the readily available biomass sources, keratin and glycol chitosan, were selected to develop a UV-curable hydrogel that is feasible for the 3D bioprinting process. Keratin methacrylate and glycol chitosan methacrylate were synthesized, and a hybrid bioink was created by combining this protein-polysaccharide cross-linked hydrogel. While human hair keratin could provide biological functions, the other composition, glycol chitosan, could further enhance the mechanical strength of the construct. The mechanical properties, degradation profile, swelling behavior, cell viability, and proliferation were investigated with various ratios of keratin methacrylate to glycol chitosan methacrylate. The composition of 2% (w/v) keratin methacrylate and 2% (w/v) chitosan methacrylate showed a significantly higher cell number and swelling percentage than other compositions and was designated as the bioink for 3D printing afterward. The feasibility of stem cell loading in the selected formula was examined with an extrusion-based bioprinter. The cells and spheroids can be successfully printed with the synthesized bioink into a specific shape and cultured. This work provides a potential option for bioinks and delivers insights into personalization research on stem cell-laden biofabricated hydrogels in the future.


Subject(s)
Bioprinting , Chitosan , Bioprinting/methods , Humans , Hydrogels/chemistry , Keratins , Methacrylates , Printing, Three-Dimensional , Stem Cells , Tissue Engineering/methods , Tissue Scaffolds/chemistry
8.
J Hazard Mater ; 432: 128658, 2022 06 15.
Article in English | MEDLINE | ID: mdl-35290896

ABSTRACT

Considering the chemical complexity and toxicity data gaps of environmental mixtures, most studies evaluate the chemical risk individually. However, humans are usually exposed to a cocktail of chemicals in real life. Mixture health assessment remains to be a research area having significant knowledge gaps. Characterization of chemical composition and bioactivity/toxicity are the two critical aspects of mixture health assessments. This review seeks to introduce the recent progress and tools for the chemical and biological characterization of environmental mixtures. The state-of-the-art techniques include the sampling, extraction, rapid detection methods, and the in vitro, in vivo, and in silico approaches to generate the toxicity data of an environmental mixture. Application of these novel methods, or new approach methodologies (NAMs), has increased the throughput of generating chemical and toxicity data for mixtures and thus refined the mixture health assessment. Combined with computational methods, the chemical and biological information would shed light on identifying the bioactive/toxic components in an environmental mixture.


Subject(s)
Risk Assessment , Humans , Risk Assessment/methods
9.
ACS Meas Sci Au ; 2(6): 576-583, 2022 Dec 21.
Article in English | MEDLINE | ID: mdl-36785775

ABSTRACT

Scanning electrochemical microscopy (SECM) is one of the scanning probe techniques that has attracted considerable attention because of its ability to interrogate surface morphology or electrochemical reactivity. However, the quality of SECM images generally depends on the sizes of the electrodes and many uncontrollable factors. Furthermore, manipulating fragile glass ultramicroelectrodes and blurred images sometimes frustrate researchers. To overcome the challenges of modern SECM, we developed novel soft gold probes and then established the AI-assisted methodology for image fusion. A novel gold microelectrode probe with high softness was developed to scan fragile samples. The distribution of EGFR (protein biomarker) in oral cancer was investigated. Then, we fused the optical microscopic and SECM images to enhance the image quality using Matlab software. However, thousands of fused images were generated by changing the parameters for image fusion, which is annoying for researchers. Thus, a deep learning model was built to select the best-fused images according to the contrast and clarity of the fused images. Therefore, the quality of the SECM images was improved using a novel soft probe and combining the image fusion technique. In the future, a new scanning probe with AI-assisted fused SECM image processing may be interpreted more preciously and contribute to the early detection of cancers.

10.
Polymers (Basel) ; 13(24)2021 Dec 13.
Article in English | MEDLINE | ID: mdl-34960904

ABSTRACT

Lung cancer has the highest global mortality rate of any cancer. Although targeted therapeutic drugs are commercially available, the common drug resistance and insensitivity to cisplatin-based chemotherapy, a common clinical treatment for lung cancer, have prompted active research on alternative lung cancer therapies and methods for mitigating cisplatin-related complications. In this study, we investigated the effect of WSG, a glucose-rich, water soluble polysaccharide derived from Ganoderma lucidum, on cisplatin-based treatment for lung cancer. Murine Lewis lung carcinoma (LLC1) cells were injected into C57BL/6 mice subcutaneously and through the tail vein. The combined administration of WSG and cisplatin effectively inhibited tumor growth and the formation of metastatic nodules in the lung tissue of the mice. Moreover, WSG increased the survival rate of mice receiving cisplatin. Co-treatment with WSG and cisplatin induced a synergistic inhibitory effect on the growth of lung cancer cells, enhancing the apoptotic responses mediated by cisplatin. WSG also reduced the cytotoxic effect of cisplatin in both macrophages and normal lung fibroblasts. Our findings suggest that WSG can increase the therapeutic effectiveness of cisplatin. In clinical settings, WSG may be used as an adjuvant or supplementary agent.

11.
Molecules ; 26(18)2021 Sep 08.
Article in English | MEDLINE | ID: mdl-34576940

ABSTRACT

Harvesting salinity gradient energy, also known as "osmotic energy" or "blue energy", generated from the free energy mixing of seawater and fresh river water provides a renewable and sustainable alternative for circumventing the recent upsurge in global energy consumption. The osmotic pressure resulting from mixing water streams with different salinities can be converted into electrical energy driven by a potential difference or ionic gradients. Reversed-electrodialysis (RED) has become more prominent among the conventional membrane-based separation methodologies due to its higher energy efficiency and lesser susceptibility to membrane fouling than pressure-retarded osmosis (PRO). However, the ion-exchange membranes used for RED systems often encounter limitations while adapting to a real-world system due to their limited pore sizes and internal resistance. The worldwide demand for clean energy production has reinvigorated the interest in salinity gradient energy conversion. In addition to the large energy conversion devices, the miniaturized devices used for powering a portable or wearable micro-device have attracted much attention. This review provides insights into developing miniaturized salinity gradient energy harvesting devices and recent advances in the membranes designed for optimized osmotic power extraction. Furthermore, we present various applications utilizing the salinity gradient energy conversion.

12.
JACS Au ; 1(5): 598-611, 2021 May 24.
Article in English | MEDLINE | ID: mdl-34056635

ABSTRACT

Skin problems are often overlooked due to a lack of robust and patient-friendly monitoring tools. Herein, we report a rapid, noninvasive, and high-throughput analytical chemical methodology, aiming at real-time monitoring of skin conditions and early detection of skin disorders. Within this methodology, adhesive sampling and laser desorption ionization mass spectrometry are coordinated to record skin surface molecular mass in minutes. Automated result interpretation is achieved by data learning, using similarity scoring and machine learning algorithms. Feasibility of the methodology has been demonstrated after testing a total of 117 healthy, benign-disordered, or malignant-disordered skins. Remarkably, skin malignancy, using melanoma as a proof of concept, was detected with 100% accuracy already at early stages when the lesions were submillimeter-sized, far beyond the detection limit of most existing noninvasive diagnosis tools. Moreover, the malignancy development over time has also been monitored successfully, showing the potential to predict skin disorder progression. Capable of detecting skin alterations at the molecular level in a nonsurgical and time-saving manner, this analytical chemistry platform is promising to build personalized skin care.

13.
Biosens Bioelectron ; 168: 112429, 2020 Nov 15.
Article in English | MEDLINE | ID: mdl-32942183

ABSTRACT

Advances in nanoarchitectonics enable a wide variety of nanostructured electrodes with tunable shapes and surface for constructing sensitive biosensors. Herein we demonstrate the fabrication of a mesoporous gold (Au) biosensor for the specific and sensitive detection of miRNA in a relatively simple and portable manner. The electrocatalytic activity of the mesoporous Au electrode (MPGE) towards the redox reaction of Fe(CN)6]3-/4- expansively examined. Leveraging the electrocatalytic activity and signal enhancement capacity of the MPGE, an ultrasensitive and specific electrochemical sensor was developed for the detection of microRNA (miRNA). The target miRNA from spiked samples is selectively isolated and purified using magnetic bead-capture probe followed by the direct adsorption on the MPGE through direct affinity interaction between miRNA and mesoporous Au surface. The MPGE-bound miRNA is then quantified by differential pulse voltammetry (DPV) using [Fe(CN)6]4-/3- redox system (Faradaic current decrease with reference to the bare MPGE). This method evades the cumbersome PCR (polymerase chain reaction) and enzymatic amplification steps. This is a single-step assay building which can detect a wide dynamic linear range (100 aM to 1 nM) of miRNA with an ultra-low limit detection of 100 aM and present high translational potentiality for the development of high-performance detection tools for clinics.


Subject(s)
Biosensing Techniques , MicroRNAs , Nanostructures , Electrochemical Techniques , Electrodes , Gold , Limit of Detection
14.
Anal Chem ; 91(20): 12900-12908, 2019 10 15.
Article in English | MEDLINE | ID: mdl-31529964

ABSTRACT

A noninvasive electrochemical melanoma detection approach based on using adhesive tapes for collecting and fixing cells from a suspicious skin area and transferring the cells into a scanning electrochemical microscope (SECM) is presented. The adhesive layer collects the cells reproducibly and keeps them well adhered on the tape during experiments in an electrolyte solution. A melanoma biomarker, here the intracellular enzyme tyrosinase (TYR), was imaged on the tape-collected cells without further cell lysing using antibodies that were labeled with horseradish peroxidase (HRP). The HRP labels catalyzed the oxidation of a dissolved redox-active species, which was detected at a soft microelectrode, gently brushed in contact mode over the tape. The melanoma biomarker was first detected on tape-stripped samples with murine melanoma cells of different concentrations. Thereafter, increasing levels of TYR were recorded in cells that were collected from the skin of melanoma mouse models representing three different stages of tumor growth. Additionally, SECM results of tape-stripped different human melanoma cell lines were confirmed by previous studies based on traditionally fixed and permeabilized cells.


Subject(s)
Adhesives/chemistry , Biomarkers, Tumor/metabolism , Melanoma, Experimental/diagnosis , Microscopy, Electrochemical, Scanning/methods , Skin Neoplasms/diagnosis , Animals , Antibodies, Monoclonal/immunology , Antibodies, Monoclonal/metabolism , Catalysis , Horseradish Peroxidase/metabolism , Humans , Melanoma, Experimental/immunology , Melanoma, Experimental/metabolism , Mice , Monophenol Monooxygenase/metabolism , Oxidation-Reduction , Skin Neoplasms/immunology , Skin Neoplasms/metabolism , Tumor Cells, Cultured
15.
Chem Sci ; 9(20): 4546-4554, 2018 May 28.
Article in English | MEDLINE | ID: mdl-29899947

ABSTRACT

The technological and experimental progress in electrochemical imaging of biological specimens is discussed with a view on potential applications for skin cancer diagnostics, reproductive medicine and microbial testing. The electrochemical analysis of single cell activity inside cell cultures, 3D cellular aggregates and microtissues is based on the selective detection of electroactive species involved in biological functions. Electrochemical imaging strategies, based on nano/micrometric probes scanning over the sample and sensor array chips, respectively, can be made sensitive and selective without being affected by optical interference as many other microscopy techniques. The recent developments in microfabrication, electronics and cell culturing/tissue engineering have evolved in affordable and fast-sampling electrochemical imaging platforms. We believe that the topics discussed herein demonstrate the applicability of electrochemical imaging devices in many areas related to cellular functions.

16.
J Nurs Manag ; 26(2): 227-237, 2018 Mar.
Article in English | MEDLINE | ID: mdl-28960600

ABSTRACT

AIMS: Develop the patient-centred innovation questionnaire for hospital nurses and establish its validity and reliability. BACKGROUND: Patient-centred care has been adopted by health care managers in their efforts to improve health care quality. It is regarded as a core concept for developing innovation. METHODS: A cross-sectional study was employed to collect data from hospital nurses in Taiwan. This study was divided into two stages: pilot study and main study. In the main study, 596 valid responses were collected. This study adopted reliability analysis, exploratory factor analysis, confirmatory factor analysis and selected nurse innovation scale as a criterion to test criterion-related validity. RESULTS: Five-dimension patient-centred innovation questionnaire was proposed: access and practicability, co-ordination and communication, sharing power and responsibility, care continuity, family and person focus. Each dimension demonstrated a reliability of 0.89-0.98. All dimensions had acceptable convergent and discriminate validity. The patient-centred innovation questionnaire and nurse innovation scale exhibited a significantly positive correlation. CONCLUSIONS: Patient-centred innovation questionnaire not only had a good theoretical basis but also had sufficient reliability and construct validity, and criterion-related validity. IMPLICATIONS FOR NURSING MANAGEMENT: Patient-centred innovation questionnaire could give a measure for evaluating the implementation of patient-centred care and could be used as a management tool during the process of nurse innovation.


Subject(s)
Nurses/psychology , Patient-Centered Care/methods , Psychometrics/instrumentation , Psychometrics/standards , Adult , Cross-Sectional Studies , Data Interpretation, Statistical , Female , Humans , Male , Middle Aged , Nurses/statistics & numerical data , Organizational Innovation , Patient-Centered Care/standards , Patient-Centered Care/statistics & numerical data , Pilot Projects , Psychometrics/statistics & numerical data , Reproducibility of Results , Surveys and Questionnaires , Taiwan
17.
Angew Chem Int Ed Engl ; 56(52): 16498-16502, 2017 12 22.
Article in English | MEDLINE | ID: mdl-29083542

ABSTRACT

Monitoring biomarkers and injected theranostic nanomaterials in tissues and organs plays a pivotal role in numerous medical applications ranging from cancer diagnostics to drug delivery. Scanning electrochemical microscopy has been demonstrated as a powerful tool to create highly resolved maps of the distributions of relevant biomolecules in cells and tissues without suffering from the optical interferences of conventional microscopy. We demonstrate for the first time the application of soft microelectrodes brushing in contact mode over large and thick tissues as well as organs that were immersed in an electrolyte solution. Amperometric currents were recorded based on the local flux of redox-active species locally and specifically generated by the biomarkers and nanomaterials to create maps of the biodistribution of graphene oxide nanoribbons in mouse livers, prognostic protein biomarkers in human melanoma and redox-active proteins in mouse heart.


Subject(s)
Biomarkers/metabolism , Electrochemical Techniques/methods , Nanostructures/chemistry , Animals , Biomarkers/analysis , Drug Carriers/chemistry , Graphite/chemistry , Humans , Magnetite Nanoparticles/chemistry , Microscopy, Confocal , Myocardium/metabolism , Myocardium/pathology , Nanotubes, Carbon/chemistry , Oxidation-Reduction , Polyethylene Glycols/chemistry , Radiopharmaceuticals/chemistry , Radiopharmaceuticals/metabolism , Ruthenium Compounds/chemistry , Single Photon Emission Computed Tomography Computed Tomography , Tissue Distribution
18.
Anal Chem ; 89(11): 5983-5990, 2017 06 06.
Article in English | MEDLINE | ID: mdl-28452215

ABSTRACT

We have realized the direct ionization of samples from wells of microtiter plates under atmospheric conditions for mass spectrometry analysis without any liquid delivery system or any additional interface. The microtiter plate is a commercially available 384-well plate without any modification, working as a container and an emitter for electrostatic spray ionization of analytes. The approach provides high throughput for the large batches of reactions and both the qualitative and quantitative analysis of a single compound or mixture. The limits of detection in small drug molecules, peptides, and proteins are similar in comparison with standard direct infusion electrospray ionization. The analysis time per well is only seconds. These analytical merits benefit many microtiter plate-based studies, such as combinatorial chemistry and high throughput screening in enzyme assay or drug metabolism. Herein, we illustrate the application in enzyme assay using tyrosine oxidation catalyzed by tyrosinase in the presence or absence of inhibitors. The potential application in drug development is also demonstrated with cytochrome P450-catalyzed metabolic reactions of two drugs in microtiter plates followed with direct ESTASI-MS/MS-based characterization of the metabolism products.


Subject(s)
Microarray Analysis/methods , Spectrometry, Mass, Electrospray Ionization/methods , Drug Development , Drug Evaluation, Preclinical , Enzyme Assays , Monophenol Monooxygenase/metabolism , Pharmaceutical Preparations/metabolism
19.
Anal Chem ; 88(23): 11436-11443, 2016 12 06.
Article in English | MEDLINE | ID: mdl-27934094

ABSTRACT

Scanning electrochemical microscopy (SECM) has been widely used for the electrochemical imaging of dynamic topographical and metabolic changes in alive adherent mammalian cells. However, extracting intracellular information by SECM is challenging, since it requires redox species to travel in and out the lipid cell membrane. Herein, we present cell fixation and permeabilization approaches as an alternative tool for visualizing cell properties by SECM. With this aim, adherent cells were analyzed in the SECM feedback mode in three different conditions: (i) alive; (ii) fixed, and (iii) fixed and permeabilized. The fixation was carried out with formaldehyde and does not damage lipid membranes. Therefore, this strategy can be used for the SECM investigation of cell topography or the passive transport of the redox mediator into the cells. Additional permeabilization of the cell membrane after fixation enables the analysis of the intracellular content through the coupling of SECM with immunoassay strategies for the detection of specific biomarkers. The latter was successfully applied as an easy and fast screening approach to detect the expression of the melanoma-associated marker tyrosinase in adherent melanoma cell lines corresponding to different cancer progression stages using the SECM substrate generation-tip collection mode. The present approach is simple, fast, and reliable and can open new ways to analyze cell cultures with electrochemically based scanning probe techniques.


Subject(s)
Biomarkers, Tumor/analysis , Immunoassay , Microscopy, Electrochemical, Scanning , Monophenol Monooxygenase/analysis , Biomarkers, Tumor/metabolism , Cell Survival , Formaldehyde/chemistry , Humans , Hydrophobic and Hydrophilic Interactions , Monophenol Monooxygenase/metabolism , Oxidation-Reduction , Tumor Cells, Cultured
20.
Angew Chem Int Ed Engl ; 55(11): 3813-6, 2016 Mar 07.
Article in English | MEDLINE | ID: mdl-26849473

ABSTRACT

Although tremendous progress has been made in the diagnosis of melanoma, the identification of different stages of malignancy in a reliable way remains challenging. Current strategies rely on optical monitoring of the concentration and spatial distribution of specific biomarkers. State-of-the-art optical methods can be affected by background-color interference and autofluorescence. We overcame these shortcomings by employing scanning electrochemical microscopy (SECM) to map the prognostic indicator tyrosinase (TyR) in non-metastatic and metastatic melanoma tissues by using soft-stylus microelectrodes. Electrochemical readout of the TyR distribution was enabled by adapting an immunochemical method. SECM can overcome the limitations of optical methods and opens unprecedented possibilities for improved diagnosis and understanding of the spatial distribution of TyR in different melanoma stages.


Subject(s)
Melanoma/enzymology , Microscopy, Electron, Scanning/methods , Monophenol Monooxygenase/metabolism , Humans , Melanoma/pathology , Neoplasm Metastasis
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