Abstract:In this work, hybrid bilayer lipid membrane (hBLM) was assembled on a mechanically polished metallurgical titanium plate. Hydrophobic molecular anchors needed for phospholipid overlayers were obtained by silanization of the Ti surface with octadecyltrichlorosilane (OTS). The formation of hBLM was accomplished by fusion of the multilamellar vesicles containing of 1, 2-dioleoyl-sn-glycero-3-phosphocholine (DOPC) and cholesterol (Chol) at molar % ratio 60/40. The fusion process was monitored in real-time by the d… Show more
“…After the silanization procedure, the values of contact angles increased to 105.13° ± 2.02° clearly demonstrating hydrophobic properties of the silanized Al surface. The obtained contact angle values of 105.13° ± 2.02° for the silanized Al surface are slightly higher than those obtained on OTS monolayer formed on mechanically polished Ti surface (102.27° ± 1.76°) 41 and lower than those obtained on OTS formed on FTO (119° ± 7°) 38 surface. However, the change of the wetting characteristics from hydrophilic to hydrophobic in all cases attests for the formation of the organic OTS monolayer on the surface, and consequently shows that functionalized metallurgical aluminum surface has sufficient surface free energy, needed for further immobilization of phospholipid layer 62 .…”
Section: Resultscontrasting
confidence: 55%
“…EIS, which is capable of detecting the dielectric properties of the surface, was applied for investigation of the hybrid bilayer formation on the metallurgical aluminum surface. Typically, the semi-circular shape of EI response in the complex capacitance plot is observed for ideally polarizable interfaces demonstrating nearly ideal capacitive behavior 26 , 34 , 41 , 68 . The approximate complex capacitance values can be obtained from the Cole–Cole plots by taking the radius of the semi-circle and multiplying it by two.…”
Section: Resultsmentioning
confidence: 99%
“…The difference in the capacitance values is an indication of void spaces (defects) in the SAM exposing the Al surface and, consequently, these defects increase the complex capacitance of the SAM 70 . Taking into account that OTS silanized mechanically polished titanium 41 and magnetron sputtered titanium 40 surfaces were successfully applied for the formation of hBLMs albeit exhibiting complex capacitance values above 1 µF cm −2 , the silanized metallurgical Al surface was also tested for the formation of bilayer lipid membranes via vesicle fusion. After immobilization of hBLMs, the complex capacitances decreased to 0.61 µF cm −2 ± 0.07 µF cm −2 (Fig.…”
Section: Resultsmentioning
confidence: 99%
“…Therefore, the magnitude of the literature clearly indicates metallurgical surfaces have extensive potential to be used as membrane-based biosensor platforms. Previously, we investigated metallurgical titanium surface for the phospholipid bilayer formation 41 , 42 , since titanium exhibits excellent biocompatibility, high chemical stability, and non-toxicity 47 . Nevertheless, preparation of metallurgical titanium surface e.g.…”
In this work we describe the functionalization of metallurgically polished aluminum surfaces yielding biomimetic electrodes suitable for probing protein/phospholipid interactions. The functionalization involves two simple steps: silanization of the aluminum and subsequent fusion of multilamellar vesicles which leads to the formation of a hybrid bilayer lipid membrane (hBLM). The vesicle fusion was followed in real-time by fast Fourier transform electrochemical impedance spectroscopy (FFT EIS). The impedance-derived complex capacitance of the hBLMs was approximately 0.61 µF cm−2, a value typical for intact phospholipid bilayers. We found that the hBLMs can be readily disrupted if exposed to > 400 nM solutions of the pore-forming peptide melittin. However, the presence of cholesterol at 40% (mol) in hBLMs exhibited an inhibitory effect on the membrane-damaging capacity of the peptide. The melittin-membrane interaction was concentration dependent decreasing with concentration. The hBLMs on Al surface can be regenerated multiple times, retaining their dielectric and functional properties essentially intact.
“…After the silanization procedure, the values of contact angles increased to 105.13° ± 2.02° clearly demonstrating hydrophobic properties of the silanized Al surface. The obtained contact angle values of 105.13° ± 2.02° for the silanized Al surface are slightly higher than those obtained on OTS monolayer formed on mechanically polished Ti surface (102.27° ± 1.76°) 41 and lower than those obtained on OTS formed on FTO (119° ± 7°) 38 surface. However, the change of the wetting characteristics from hydrophilic to hydrophobic in all cases attests for the formation of the organic OTS monolayer on the surface, and consequently shows that functionalized metallurgical aluminum surface has sufficient surface free energy, needed for further immobilization of phospholipid layer 62 .…”
Section: Resultscontrasting
confidence: 55%
“…EIS, which is capable of detecting the dielectric properties of the surface, was applied for investigation of the hybrid bilayer formation on the metallurgical aluminum surface. Typically, the semi-circular shape of EI response in the complex capacitance plot is observed for ideally polarizable interfaces demonstrating nearly ideal capacitive behavior 26 , 34 , 41 , 68 . The approximate complex capacitance values can be obtained from the Cole–Cole plots by taking the radius of the semi-circle and multiplying it by two.…”
Section: Resultsmentioning
confidence: 99%
“…The difference in the capacitance values is an indication of void spaces (defects) in the SAM exposing the Al surface and, consequently, these defects increase the complex capacitance of the SAM 70 . Taking into account that OTS silanized mechanically polished titanium 41 and magnetron sputtered titanium 40 surfaces were successfully applied for the formation of hBLMs albeit exhibiting complex capacitance values above 1 µF cm −2 , the silanized metallurgical Al surface was also tested for the formation of bilayer lipid membranes via vesicle fusion. After immobilization of hBLMs, the complex capacitances decreased to 0.61 µF cm −2 ± 0.07 µF cm −2 (Fig.…”
Section: Resultsmentioning
confidence: 99%
“…Therefore, the magnitude of the literature clearly indicates metallurgical surfaces have extensive potential to be used as membrane-based biosensor platforms. Previously, we investigated metallurgical titanium surface for the phospholipid bilayer formation 41 , 42 , since titanium exhibits excellent biocompatibility, high chemical stability, and non-toxicity 47 . Nevertheless, preparation of metallurgical titanium surface e.g.…”
In this work we describe the functionalization of metallurgically polished aluminum surfaces yielding biomimetic electrodes suitable for probing protein/phospholipid interactions. The functionalization involves two simple steps: silanization of the aluminum and subsequent fusion of multilamellar vesicles which leads to the formation of a hybrid bilayer lipid membrane (hBLM). The vesicle fusion was followed in real-time by fast Fourier transform electrochemical impedance spectroscopy (FFT EIS). The impedance-derived complex capacitance of the hBLMs was approximately 0.61 µF cm−2, a value typical for intact phospholipid bilayers. We found that the hBLMs can be readily disrupted if exposed to > 400 nM solutions of the pore-forming peptide melittin. However, the presence of cholesterol at 40% (mol) in hBLMs exhibited an inhibitory effect on the membrane-damaging capacity of the peptide. The melittin-membrane interaction was concentration dependent decreasing with concentration. The hBLMs on Al surface can be regenerated multiple times, retaining their dielectric and functional properties essentially intact.
“…Meanwhile, EIS is a non-destructive method, which is providing useful models on the effect of alternating current (AC) on the sample. EIS enables registering quantitative data, which determines properties of electrode/electrolyte boundary [2,[28][29][30][31]. However, conventional EIS-based technique has a problem because it represents only average response of a whole electrochemical system.…”
Scanning electrochemical microscopy (SECM), electrochemical impedance spectroscopy (EIS) and scanning electrochemical impedance microscopy (SEIM) were used to investigate electrochemical activity of active and inactivated yeast Saccharomyces cerevisiae cells. SEIM experiment was performed using a unique electrochemical impedance spectrometer with a fast Fourier transform (FFT‐EIS) function, which enabled simultaneously perturb/evaluate electrochemical system at 50 frequencies. This allowed very quick observing the differences between impedance spectra, which were taken every few seconds. Therefore, we were able to apply SEIM for relatively fast determination of electrochemical impedance dependence on the distance between ultramicroelectrode (UME) and surface modified by immobilized yeast cells. It was determined that electrochemical activity and ‘breathing’ (a consumption of dissolved oxygen) of yeast can be electrochemically observed when the distance between UME and surface of yeast cells is in the range from 0 μm to 25 μm. Therefore, 25 μm is the maximum distance suitable for efficient investigation of yeast cell activity when experiments are performed in FFT‐SEIM mode. Charge transfer resistance of active and inactivated yeast cells was determined using EIS. It was calculated that charge transfer resistance of active yeast cells is 1.5 times lower than that of inactivated yeast cells. Lipophilic vitamin K3 (Vit‐K3) and hydrophilic vitamin K1 (Vit‐K1) were mixtured and used as redox mediators for charge transfer from yeast cells.
In this work mixed hybrid phospholipid bilayers (mhBLM) were deposited on fluorine doped tin oxide (FTO) films. Two component silane‐based self‐assembled monolayers (SAMs) formed on FTO surface trigger vesicle fusion and formation of mhBLMs which are stable, can be easily regenerated, and therefore, used for multiple experiments. We found that certain chemical and physical conditions under which mixed SAMs are fabricated translate into functional properties of mhBLMs. In all cases we observed interaction of melittin with mhBLMs demonstrating biological relevance of these biomimetic surface constructs and their possible application in biosensors for toxin detection.
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