SU-8 based pyrolytic carbon for the electrochemical detection of dopamine

Peltola, Emilia; Heikkinen, Joonas J.; Sovanto, Katariina; Sainio, Sami; Aarva, Anja; Franssila, Sami; Jokinen, Ville; Laurila, Tomi

doi:10.1039/c7tb02469j

Cited by 33 publications

(45 citation statements)

References 54 publications

(61 reference statements)

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“…Both OEFs and LOEFs show a linear relationship with the square root of the scan rate up to 900 mV s −1 indicating that the conductivity of the pyrolytic carbon does not limit electrochemical processes at higher scan rates (Figure b). Moreover, oxygen plasma treatment has been reported to increase the electron transport resistance of pyrolytic carbon, however on the LOEFs, we did not observe any significant widening of Δ E p with oxygen plasma treatment (before plasma: 81.3 ± 3 vs 80.3 ± 3 mV after plasma at 50 mV s −1 ). The LOEFs demonstrate quasi‐reversible reaction kinetics indicated by the widening of Δ E p with scan rate from 80 mV at 25 mV s −1 to 117 mV at 900 mV s −1 (Figure S2c,d, Supporting Information).…”

Section: Resultscontrasting

confidence: 69%

Leaky Optoelectrical Fiber for Optogenetic Stimulation and Electrochemical Detection of Dopamine Exocytosis from Human Dopaminergic Neurons

et al. 2019

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In Parkinson's disease, the degeneration of dopaminergic neurons in substantia nigra leads to a decrease in the physiological levels of dopamine in striatum. The existing dopaminergic therapies effectively alleviate the symptoms, albeit they do not revert the disease progression and result in significant adverse effects. Transplanting dopaminergic neurons derived from stem cells could restore dopamine levels without additional motor complications. However, the transplanted cells disperse in vivo and it is not possible to stimulate them on demand to modulate dopamine release to prevent dyskinesia. In order to address these issues, this paper presents a multifunctional leaky optoelectrical fiber for potential neuromodulation and as a cell substrate for application in combined optogenetic stem cell therapy. Pyrolytic carbon coated optical fibers are laser ablated to pattern micro‐optical windows to permit light leakage over a large area. The pyrolytic carbon acts as an excellent electrode for the electrochemical detection of dopamine. Human neural stem cells are genetically modified to express the light sensitive opsin channelrhodopsin‐2 and are differentiated into dopaminergic neurons on the leaky optoelectrical fiber. Finally, light leaking from the micro‐optical windows is used to stimulate the dopaminergic neurons resulting in the release of dopamine that is detected in real‐time using chronoamperometry.

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Section: Resultscontrasting

confidence: 69%

Leaky Optoelectrical Fiber for Optogenetic Stimulation and Electrochemical Detection of Dopamine Exocytosis from Human Dopaminergic Neurons

et al. 2019

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“…Sample fabrication details are provided as supplementary material and the more detailed description of the a-C deposition process can be found from 8 , for ta-C and ND from 19 , and that of PyC from 29 . Amorphous carbon (a-C) films with varying oxygen or hydrogen content were deposited by closed-field unbalanced magnetron sputtering.…”

Section: Substrate Fabricationmentioning

confidence: 99%

“…Thus, there are more reactants near the electrode than there would be without adsorption. Indeed, on PyC the DA reaction kinetics is both diffusion and adsorption defined 29 . 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 Furthermore, the large drop in I po by the 2 nd cycle (2 nd cycle 63% of the 1 st on PyC, while it remains > 70% on other tested electrode materials) with hardly any effect on E po (4 mV for PyC) indicate a formation of a (probably thin) layer on the surface during the first cycle.…”

Section: Electrochemistrymentioning

confidence: 99%

Electrochemical Fouling of Dopamine and Recovery of Carbon Electrodes

et al. 2017

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A significant problem with implantable sensors is electrode fouling, which has been proposed as the main reason for biosensor failures in vivo. Electrochemical fouling is typical for dopamine (DA) as its oxidation products are very reactive and the resulting polydopamine has a robust adhesion capability to virtually all types of surfaces. The degree of DA fouling of different carbon electrodes with different terminations was determined using cyclic voltammetry (CV) and scanning electrochemical microscopy (SECM) approach curves and imaging. The rate of electron transfer kinetics at the fouled electrode surface was determined from SECM approach curves, allowing a comparison of insulating film thickness for the different terminations. SECM imaging allowed the determination of different morphologies, such as continuous layers or islands, of insulating material. We show that heterogeneous modification of carbon electrodes with carboxyl-amine functionalities offers protection against formation of an insulating polydopamine layer, while retaining the ability to detect DA. The benefits of the heterogeneous termination are proposed to be due to the electrostatic repulsion between amino-functionalities and DA. Furthermore, we show that the conductivity of the surfaces as well as the response toward DA was recovered close to the original performance level after cleaning the surfaces for 10-20 cycles in HSO on all materials but pyrolytic carbon (PyC). The recovery capacity of the PyC electrode was lower, possibly due to stronger adsorption of DA on the surface.

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“…Furthermore, by building carbon hybrid nanomaterials, e.g., by combining ta-C and ND, detection of concentrations down to 100 nM DA is possible. Also, by utilizing surface oxidizing treatments such as nitric acid treatments [18], improvements in the sensitivity have been achieved [5,7,20,22]. Despite all these efforts, the ability to selectively detect DA and AA has not been reached using only metal-free (or very low metal concentration) carbonbased nanomaterials.…”

Section: Electrochemical Detection Of Neurotransmittersmentioning

confidence: 99%

Integrating Carbon Nanomaterials with Metals for Bio-sensing Applications

et al. 2019

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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.

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SU-8 based pyrolytic carbon for the electrochemical detection of dopamine

Abstract: Here we investigated the electrochemical properties and dopamine (DA) detection capability of SU-8 photoresist based pyrolytic carbon (PyC) as well as its biocompatibility with neural cells.

Cited by 33 publications

References 54 publications

Leaky Optoelectrical Fiber for Optogenetic Stimulation and Electrochemical Detection of Dopamine Exocytosis from Human Dopaminergic Neurons

Leaky Optoelectrical Fiber for Optogenetic Stimulation and Electrochemical Detection of Dopamine Exocytosis from Human Dopaminergic Neurons

Electrochemical Fouling of Dopamine and Recovery of Carbon Electrodes

Integrating Carbon Nanomaterials with Metals for Bio-sensing Applications

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