Browsing by Author "Mynttinen, Elsi"

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  • Differentiation of Human Mesenchymal Stem Cells into Dopaminergic Neurons on Brain Electrode Materials
    (2016-08-24) Mynttinen, Elsi
     Sähkötekniikan korkeakoulu | Master's thesis
    Mesenchymal stem cells (MSCs) are multipotent cells that can differentiate into various cell types depending on their environment, but cannot undergo neurogenesis in normal conditions. In contrast, with the appropriate chemical and mechanical stimuli, these cells can be guided towards the neuronal lineage in vitro. Moreover, the generated neurons can be further directed into a dopaminergic (DA) subgroup. This process, however, requires optimal growth conditions, as well as suitable substrates for controlling the cell fate. In this thesis work, human MSCs (hMSCs) were differentiated into DA neurons on four different carbon-based materials and the differentiation process with and without differentiation factors was assessed by following markers related to neurogenesis. The substrate materials were tetrahedral amorphous carbon (ta-C), ta-C coated with poly-D-lysine (PDL), ta-C coated with carbon nanodiamonds (vox) and vox functionalized with brain-derived neurotrophic factor (BDNF). The differentiation medium was a cocktail of BDNF, sonic hedgehog (Shh) and fibroblast growth factors (FGF2 and FGF8). The expressions of glial fibrillary acidic protein (GFAP), nestin, neuron-specific enolase (NSE) and thyrosine hydroxylase (TH) were tracked by immunofluorescence staining and quantitative real-time polymerase chain reaction (RT-qPCR). The results showed the ability of the differentiation medium to induce neuron-like morphology in the cells cultured for 12 days on all material types. In addition, the marker profiles revealed a positive effect of the nanostructures on the MSC differentiation, while PDL coating was found unfavorable for MSCs. Furthermore, the results also indicate that the differentiation process had not been fully completed by the day 12, implying a need for a longer period in culture. These experiments demonstrate various challenges related to developing an efficient protocol for DA differentiation from hMSCs, the most important being the optimization of the combined mechanical and chemical stimuli. Nevertheless, the use of MSCs holds great promise for therapeutic approaches in several medical conditions including spinal cord injuries and neurodegenerative disorders such as Parkinson’s disease.
  • Electrochemical Detection of Oxycodone and Its Main Metabolites with Nafion-Coated Single-Walled Carbon Nanotube Electrodes
    (2020-05-15) Mynttinen, Elsi; Wester, Niklas; Lilius, Tuomas; Kalso, Eija; Mikladal, Bjørn; Varjos, Ilkka; Sainio, Sami; Jiang, Hua; Kauppinen, Esko; Koskinen, Jari; Laurila, Tomi
     A1 Alkuperäisartikkeli tieteellisessä aikakauslehdessä
    Oxycodone is a strong opioid frequently used as an analgesic. Although proven efficacious in the management of moderate to severe acute pain and cancer pain, use of oxycodone imposes a risk of adverse effects such as addiction, overdose, and death. Fast and accurate determination of oxycodone blood concentration would enable personalized dosing and monitoring of the analgesic as well as quick diagnostics of possible overdose in emergency care. However, in addition to the parent drug, several metabolites are always present in the blood after a dose of oxycodone, and to date, there is no electrochemical data available on any of these metabolites. In this paper, a single-walled carbon nanotube (SWCNT) electrode and a Nafion-coated SWCNT electrode were used, for the first time, to study the electrochemical behavior of oxycodone and its two main metabolites, noroxycodone and oxymorphone. Both electrode types could selectively detect oxycodone in the presence of noroxycodone and oxymorphone. However, we have previously shown that addition of a Nafion coating on top of the SWCNT electrode is essential for direct measurements in complex biological matrices. Thus, the Nafion/SWCNT electrode was further characterized and used for measuring clinically relevant concentrations of oxycodone in buffer solution. The limit of detection for oxycodone with the Nafion/SWCNT sensor was 85 nM, and the linear range was 0.5–10 μM in buffer solution. This study shows that the fabricated Nafion/SWCNT sensor has potential to be applied in clinical concentration measurements.
  • Integrating Carbon Nanomaterials with Metals for Bio-sensing Applications
    (2019-01-01) Sainio, Sami; Leppänen, Elli; Mynttinen, Elsi; Palomäki, Tommi; Wester, Niklas; Etula, Jarkko; Isoaho, Noora; Peltola, Emilia; Koehne, Jessica; Meyyappan, M.; Koskinen, Jari; Laurila, Tomi
     A1 Alkuperäisartikkeli tieteellisessä aikakauslehdessä
    Age structure in most developed countries is changing fast as the average lifespan is increasing significantly, calling for solutions to provide improved treatments for age-related neurological diseases and disorders. In order to address these problems, a reliable way of recording information about neurotransmitters from in vitro and in vivo applications is needed to better understand neurological diseases and disorders as well as currently used treatments. Likewise, recent developments in medicine, especially with the opioid crisis, are demanding a swift move to personalized medicine to administer patient needs rather than population-wide averages. In order to enable the so-called personalized medicine, it is necessary to be able to do measurements in vivo and in real time. These actions require sensitive and selective detection of different analytes from very demanding environments. Current state-of-the-art materials are unable to provide sensitive and selective detection of neurotransmitters as well as the required time resolution needed for drug molecules at a reasonable cost. To meet these challenges, we have utilized different metals to grow carbon nanomaterials and applied them for sensing applications showing that there are clear differences in their electrochemical properties based on the selected catalyst metal. Additionally, we have combined atomistic simulations to support optimizing materials for experiments and to gain further understanding of the atomistic level reactions between different analytes and the sensor surface. With carbon nanostructures grown from Ni and Al + Co + Fe hybrid, we can detect dopamine, ascorbic acid, and uric acid simultaneously. On the other hand, nanostructures grown from platinum provide a feasible platform for detection of H2O2 making them suitable candidates for enzymatic biosensors for detection of glutamate, for example. Tetrahedral amorphous carbon electrodes have an ability to detect morphine, paracetamol, tramadol, and O-desmethyltramadol. With carbon nanomaterial-based sensors, it is possible to reach metal-like properties in sensing applications using only a fraction of the metal as seed for the material growth. We have also seen that by using nanodiamonds as growth catalyst for carbon nanofibers, it is not possible to detect dopamine and ascorbic acid simultaneously, although the morphology of the resulting nanofibers is similar to the ones grown using Ni. This further indicates the importance of the metal selection for specific applications. However, Ni as a continuous layer or as separate islands does not provide adequate performance. Thus, it appears that metal nanoparticles combined with fiber-like morphology are needed for optimized sensor performance for neurotransmitter detection. This opens up a new research approach of application-specific nanomaterials, where carefully selected metals are integrated with carbon nanomaterials to match the needs of the sensing application in question.
  • Kationisten polymeerien antibakteeriset sovellukset
    (2013-12-20) Mynttinen, Elsi
     Sähkötekniikan korkeakoulu | Bachelor's thesis
  • Nafion-ohutkalvojen rakenne ja ominaisuudet
    (2019-09-01) Tommila, Timo
     Sähkötekniikan korkeakoulu | Bachelor's thesis
  • Opioidien sähkökemiallinen havaitseminen biologisista näytteistä
    (2017-09-26) Hoffström, Jaakko
     Sähkötekniikan korkeakoulu | Bachelor's thesis
  • Perm-selective membranes in the electrochemical detection of analgesics
    (2017-08-31) Leinonen, Milja
     Sähkötekniikan korkeakoulu | Bachelor's thesis
  • Simultaneous Detection of Morphine and Codeine in the Presence of Ascorbic Acid and Uric Acid and in Human Plasma at Nafion Single-Walled Carbon Nanotube Thin-Film Electrode
    (2019-01-01) Wester, Niklas; Mynttinen, Elsi; Etula, Jarkko; Lilius, Tuomas; Kalso, Eija; Kauppinen, Esko I.; Laurila, Tomi; Koskinen, Jari
     A1 Alkuperäisartikkeli tieteellisessä aikakauslehdessä
    In clinical settings, the dosing and differential diagnosis of the poisoning of morphine (MO) and codeine (CO) is challenging due to interindividual variations in metabolism. However, direct electrochemical detection of these analytes from biological matrices is inherently challenging due to interference from large concentrations of anions, such as ascorbic acid (AA) and uric acid (UA), as well as fouling of the electrode by proteins. In this work, a disposable Nafion-coated single-walled carbon nanotube network (SWCNT) electrode was developed. We show facile electron transfer and efficient charge separation between the interfering anions and positively charged MO and CO, as well as significantly reduced matrix effect in human plasma. The Nafion coating alters the voltammetric response of MO and CO, enabling simultaneous detection. With this SWCNT/Nafion electrode, two linear ranges of 0.05-1 and 1-10 μM were found for MO and one linear range of 0.1-50 μM for CO. Moreover, the selective and simultaneous detection of MO and CO was achieved in large excess of AA and UA, as well as, for the first time, in unprocessed human plasma. The favorable properties of this electrode enabled measurements in plasma with only mild dilution and without the precipitation of proteins.
  • Simultaneous electrochemical detection of tramadol and O-desmethyltramadol with Nafion-coated tetrahedral amorphous carbon electrode
    (2019-02-01) Mynttinen, Elsi; Wester, Niklas; Lilius, Tuomas; Kalso, Eija; Koskinen, Jari; Laurila, Tomi
     A1 Alkuperäisartikkeli tieteellisessä aikakauslehdessä
    Tramadol (TR) is a member of the opioid family and is widely used for pain treatment in clinical patient care. The analgesic effect of tramadol is induced primarily by its main metabolite O-desmethyltramadol (ODMT). Due to inter-individual differences in the TR metabolism to ODMT, the responses to TR vary highly between patients. Thus, a fast and selective method for simultaneous detection of TR and ODMT would increase the patient safety and pain treatment efficacy. In this study, a tetrahedral amorphous carbon (ta-C) electrode coated with a thin dip-coated recast Nafion membrane was fabricated for selective electrochemical determination of TR and ODMT. With this Nafion/ta-C electrode, simultaneous detection of TR and ODMT was achieved with linear ranges of 1–12.5 μM and 1–15 μM, respectively. The limits of detection were 131 nM for TR and 209 nM for ODMT. Both analytes were also measured in the presence of several common interferents, demonstrating the high selectivity of the fabricated electrode. In addition, the effect of pH on the peak potential was studied to observe the electrochemical behavior of the analytes at the electrode. Finally, clinically relevant concentrations of TR and ODMT were simultaneously detected from diluted human plasma to assess the applicability of the electrode in real samples. The fabricated Nafion/ta-C electrode was found successful in the simultaneous electrochemical detection of TR and ODMT in both buffer solution and in human plasma.
  • Single-Walled Carbon Nanotube Network Electrodes for the Detection of Fentanyl Citrate
    (2020-02-28) Wester, Niklas; Mynttinen, Elsi; Etula, Jarkko; Lilius, Tuomas; Kalso, Eija; Mikladal, Bjørn F.; Zhang, Qiang; Jiang, Hua; Sainio, Sami; Nordlund, Dennis; Kauppinen, Esko I.; Laurila, Tomi; Koskinen, Jari
     A1 Alkuperäisartikkeli tieteellisessä aikakauslehdessä
    We prepare disposable single-walled carbon nanotube network electrodes for the detection of the potent opioid fentanyl, currently a leading cause for opioid overdose deaths in the USA. We show repeatable dry transfer of single-walled carbon nanotube (SWCNT) networks to produce robust electrodes. This process directly produces highly conductive SWCNT electrodes without the need for any further modifications required for conventional carbon electrodes. The realized electrode showed low background currents combined with spontaneous enrichment of fentanyl, resulting in a high signal-to-noise ratio. With this electrode, a detection limit of 11 nM and a linear range of 0.01-1 μM were found for fentanyl. In addition, selectivity is demonstrated in the presence of several common interferents.
  • Tramadolin ja oksikodonin sähkökemiallinen mittaaminen ja metabolia ihmiskehossa
    (2018-08-29) Leikas, Antti
     Sähkötekniikan korkeakoulu | Bachelor's thesis