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IRG 4: Carbon Based Sensors and Bio-Sensors


Develop gas conductivity-based and enzymatic sensing processes for air and water environments in collaboration with NASA ARC.

 

Sub-Theme A: Bio-Sensors

 

NASA Collaborator: Dr. Meyya Meyyappan

UPR: Carlos R. Cabrera and Kai Griebenow

 

 

Protein Chemical Glycosylation: A Stabilization Method for Biosensor Application

 

The goal of this project is an excellent match to the goals and objectives of NASA. Since lactate levels in blood are a long-established indicator for physical fitness in humans, our long-term goal is to develop a robust and stable LOx based biosensor for space missions.

 

Mayor problems of biosensors:

•           Lack of sensitivity

•           Lack of long term stability

 

A good strategy to overcome these problems in biosensor is to use carbon nanotube as principal matrix to attach the biomolecule. Some of these advantages are:

–        Improved the electron transfer reaction between protein and electrode

–        Decrease the overpotential and enhanced the sensitivity of the biosensor

–        Can be functionalized

The central hypothesis of the research is that covalent chemical modification of the enzyme with glycans will reduce conformational motions (dynamics) and increase its thermodynamic stability thus positively affecting long-term stability.

 

Sub-Theme B: Carbon-Based Sensors

Development of nano-metallic decorated single wall carbon nanotubes sensors for non-polar gas detection

This work is currently done at NASA-Ames Research Center by Enid Contes-de Jesus, CANM Graduate Student and GSRP Recipient, under the guidance and mentorship of Dr. Jing Li, NASA Collaborator.

 

Objectives:

  1. To test the sensors towards the detection of Cl2 from higher to lower concentrations .
    1. 20, 15, 10, 7, 5, 3 ppm
  2. To test the recovery of the sensors after the detection of Cl2.

 

Experimental Section and Results:

Objective #1: The base resistance was measured at 400ccm for different concentration of Cl2 using air as blending gas.

 

Results:

Our samples of Pt/SWCNTs were able to detect Cl2 at the different concentrations (20, 15, 10, 7, 5 ppm) under air. The same concentrations were also detected when going from lower to higher concentrations.  It is very important to remark that the detection of 3ppm was achieved even after previous exposure to higher concentrations (up to 20 ppm) and even when the sensor did not recover completely during the purging time (between the different concentrations). This test was repeated and the same results were obtained.