[seminar] S. Yitzchaik, 22.2. (četvrtak) 14h (c.t.), seminar ZTF-a

[Anđelo Samsarov]

                 SEMINAR  TEORIJSKE  FIZIKE


    (Zajednički seminari Fizičkog odsjeka PMF-a te Zavoda za teorijsku
     fiziku i Zavoda za eksperimentalnu fiziku IRB-a)

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      Conformationally Adaptive Biosensors


      S. Yitzchaik
      Institute of Chemistry and the Center for Nanoscience and
      Nanotechnology,
      the Hebrew University of Jerusalem



    Datum:  četvrtak, 22. veljače 2018.
    Vrijeme: 14 sati c.t.
    Mjesto: IRB, predavaona III krila


   Sažetak:

     In this contribution we’ll exemplified the usefulness of label  
free electrochemical biosensors that utilizes proteins and peptides  
conformational changes for improved biosensing. Molecular recognition  
events accompanied with conformational alternation are prone to  
undergo collective structural change when assembled in monolayers.  
This phenomenon is demonstrated for ions, small molecules and proteins  
biosensing. A case study for neurodegenerative disease will be  
described in depth.
Zinc and copper are essential metal ions for numerous biological  
processes. Their levels are tightly maintained in all body organs.  
Impairment of the Zn2+ to Cu2+ ratio in serum was found to correlate  
with many disease states, including immunological and inflammatory  
disorders. Oxytocin (OT) is a neuropeptide, and its activity is  
modulated by zinc and copper ion binding. Harnessing the intrinsic  
properties of OT is one of the attractive ways to develop valuable  
metal ion sensors. In this talk, we report an OT-based metal ion  
sensor prepared by immobilizing the neuropeptide onto a glassy carbon  
electrode. The developed impedimetric biosensor was ultrasensitive to  
Zn2+ and Cu2+ ions at physiological pH and not to other biologically  
relevant ions. Interestingly, the electrochemical impedance signal of  
two hemicircle systems was recorded after the attachment of OT to the  
surface. These two semicircles suggest two capacitive regions that  
result from two different domains in the OT monolayer. Moreover, the  
change in the charge-transfer resistance of either Zn2+ or Cu2+ was  
not similar in response to binding. This suggests that the  
metal-dependent conformational changes of OT can be translated to  
distinct impedimetric data. Selective masking of Zn2+ and Cu2+ was  
used to allow for the simultaneous determination of zinc to copper  
ions ratio by the OT sensor. The OT sensor was able to distinguish  
between healthy control and multiple sclerosis patients diluted sera  
samples by determining the Zn/Cu ratio similar to the state-of-the-art  
techniques. The OT sensor presented herein is likely to have numerous  
applications in biomedical research and pave the way to other types of  
neuropeptide-derived sensors.






Voditelj seminara: Anđelo Samsarov (asamsarov at irb.hr)

http://thphys.irb.hr/Seminar/list.htm
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