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ZnO Nanostructure-Based Intracellular Sensor.

Asif MH, Danielsson B, Willander M - Sensors (Basel) (2015)

Bottom Line: Recently ZnO has attracted much interest because of its usefulness for intracellular measurements of biochemical species by using its semiconducting, electrochemical, catalytic properties and for being biosafe and biocompatible.The sensors in this study were used to detect real-time changes of metal ions and glucose across human fat cells and frog cells using changes in the electrochemical potential at the interface of the intracellular micro-environment.Such devices are helpful in explaining various intracellular processes involving ions and glucose.

View Article: PubMed Central - PubMed

Affiliation: Department of Physics, COMSATS Institute of Information Technology, Lahore 54000, Pakistan. asifhassan@ciitlahore.edu.pk.

ABSTRACT
Recently ZnO has attracted much interest because of its usefulness for intracellular measurements of biochemical species by using its semiconducting, electrochemical, catalytic properties and for being biosafe and biocompatible. ZnO thus has a wide range of applications in optoelectronics, intracellular nanosensors, transducers, energy conversion and medical sciences. This review relates specifically to intracellular electrochemical (glucose and free metal ion) biosensors based on functionalized zinc oxide nanowires/nanorods. For intracellular measurements, the ZnO nanowires/nanorods were grown on the tip of a borosilicate glass capillary (0.7 µm in diameter) and functionalized with membranes or enzymes to produce intracellular selective metal ion or glucose sensors. Successful intracellular measurements were carried out using ZnO nanowires/nanorods grown on small tips for glucose and free metal ions using two types of cells, human fat cells and frog oocytes. The sensors in this study were used to detect real-time changes of metal ions and glucose across human fat cells and frog cells using changes in the electrochemical potential at the interface of the intracellular micro-environment. Such devices are helpful in explaining various intracellular processes involving ions and glucose.

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Related in: MedlinePlus

Representative K+ current recordings and the corresponding I(V) curves measured electrophysiological in Kv channel expressing Xenopus oocytes. (A) Shows data for control oocytes and (B–D) for oocytes injected with indicated test solution. The holding potential was set to −80 mV and test pulses ranging from −80 to + 50 mV. The current generated by stepping to 0 mV is marked in red in each recording [26].
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sensors-15-11787-f011: Representative K+ current recordings and the corresponding I(V) curves measured electrophysiological in Kv channel expressing Xenopus oocytes. (A) Shows data for control oocytes and (B–D) for oocytes injected with indicated test solution. The holding potential was set to −80 mV and test pulses ranging from −80 to + 50 mV. The current generated by stepping to 0 mV is marked in red in each recording [26].

Mentions: To evaluate the accuracy of potentiometric data, the intracellular K+ concentration was measured with both electrophysiological and potentiometric methods on the same oocyte. Two-electrode voltage clamp measurements of K+ currents were performed as previously described [29]. The holding potential was set to −80 mV and the currents achieved by stepping to potentials between −80 and +50 mV for 100 ms in 5 mV increments. The amplifier capacitance and leakage compensation was used. Each oocyte was then immediately transferred for potentiometric measurements (oocytes bathed in 100 mM KCl solution).ll oocytes were measured both electrophysiologically and potentiometrically within 25 min after test solution injection. The [K+]i was tested electrophysiologically to be stable for at least 25 min after 1M KCl injection [26]. The concentration determined with the two methods gave almost the same results (Figure 11).


ZnO Nanostructure-Based Intracellular Sensor.

Asif MH, Danielsson B, Willander M - Sensors (Basel) (2015)

Representative K+ current recordings and the corresponding I(V) curves measured electrophysiological in Kv channel expressing Xenopus oocytes. (A) Shows data for control oocytes and (B–D) for oocytes injected with indicated test solution. The holding potential was set to −80 mV and test pulses ranging from −80 to + 50 mV. The current generated by stepping to 0 mV is marked in red in each recording [26].
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4481971&req=5

sensors-15-11787-f011: Representative K+ current recordings and the corresponding I(V) curves measured electrophysiological in Kv channel expressing Xenopus oocytes. (A) Shows data for control oocytes and (B–D) for oocytes injected with indicated test solution. The holding potential was set to −80 mV and test pulses ranging from −80 to + 50 mV. The current generated by stepping to 0 mV is marked in red in each recording [26].
Mentions: To evaluate the accuracy of potentiometric data, the intracellular K+ concentration was measured with both electrophysiological and potentiometric methods on the same oocyte. Two-electrode voltage clamp measurements of K+ currents were performed as previously described [29]. The holding potential was set to −80 mV and the currents achieved by stepping to potentials between −80 and +50 mV for 100 ms in 5 mV increments. The amplifier capacitance and leakage compensation was used. Each oocyte was then immediately transferred for potentiometric measurements (oocytes bathed in 100 mM KCl solution).ll oocytes were measured both electrophysiologically and potentiometrically within 25 min after test solution injection. The [K+]i was tested electrophysiologically to be stable for at least 25 min after 1M KCl injection [26]. The concentration determined with the two methods gave almost the same results (Figure 11).

Bottom Line: Recently ZnO has attracted much interest because of its usefulness for intracellular measurements of biochemical species by using its semiconducting, electrochemical, catalytic properties and for being biosafe and biocompatible.The sensors in this study were used to detect real-time changes of metal ions and glucose across human fat cells and frog cells using changes in the electrochemical potential at the interface of the intracellular micro-environment.Such devices are helpful in explaining various intracellular processes involving ions and glucose.

View Article: PubMed Central - PubMed

Affiliation: Department of Physics, COMSATS Institute of Information Technology, Lahore 54000, Pakistan. asifhassan@ciitlahore.edu.pk.

ABSTRACT
Recently ZnO has attracted much interest because of its usefulness for intracellular measurements of biochemical species by using its semiconducting, electrochemical, catalytic properties and for being biosafe and biocompatible. ZnO thus has a wide range of applications in optoelectronics, intracellular nanosensors, transducers, energy conversion and medical sciences. This review relates specifically to intracellular electrochemical (glucose and free metal ion) biosensors based on functionalized zinc oxide nanowires/nanorods. For intracellular measurements, the ZnO nanowires/nanorods were grown on the tip of a borosilicate glass capillary (0.7 µm in diameter) and functionalized with membranes or enzymes to produce intracellular selective metal ion or glucose sensors. Successful intracellular measurements were carried out using ZnO nanowires/nanorods grown on small tips for glucose and free metal ions using two types of cells, human fat cells and frog oocytes. The sensors in this study were used to detect real-time changes of metal ions and glucose across human fat cells and frog cells using changes in the electrochemical potential at the interface of the intracellular micro-environment. Such devices are helpful in explaining various intracellular processes involving ions and glucose.

Show MeSH
Related in: MedlinePlus