Biosensor
• Fall 2018, seven week (half-semester) project in a team of three.
• Performed enzyme reactions in cuvette for spectrophotometry testing.
• Designed and 3D printed the casing for all circuitry and photometry components.
• Modified existing Arduino code to measure Beta-galactosidase reactions.
• Identified alternative applications for blood plasma to detect atherosclerosis.
I worked in a team of three to design and create a spectrophotometer capable of testing concentrations of enzymatic reactions. Essentially, a cuvette containing a given solution is placed between an LED and photoresistor in a self-designed 3D printed container. The latter measures the amount of light passing through the substance in the cuvette, showing the concentration of the substance being analyzed and sending this data to a computer via Arduino and breadboard, which are also contained in their own 3D printed structure.
This section explains the science behind the experiment and the chemicals being inspected. For our project, we chose the Beta-galactosidase reaction which is a simple enzyme-substrate reaction. The enzyme B-galactosidase has an active site that breaks down a molecule known as ONPG when it is bound to the active site. This process occurs in a solution of water because this molecule is used in the hydrolysis of ONPG. The product of this reaction is the creation of ONP which is visibly yellow. The device monitors the B-galactosidase reaction through the use of a photoresistor. A blue LED is on one end of the cuvette, and a photoresistor on the other. Blue light is emitted into the sample of the ONPG and B-gal reaction, represented by the product ONP's yellow hue, because it absorbs this specific wavelength of light most efficiently. The fraction of light transmitted through the sample is measured by a photoresistor that sends data through the breadboard and Arduino to be converted into readable text. The breadboard contains the circuitry in order to achieve this. There is a resistor that measures the voltage drop from the electricity of the photoresistor, which is sent to the ports of the Arduino. The second resistor pictured is so the LED doesn't burn out (rated at 330Ω). The Arduino then computes the signal and sends it to the computer in the form of text to be read by the custom coded Arduino IDE program. These transmittance values can then be used to calculate the absorbance of the sample, which in turn can be used to measure the concentration of ONP in the solution.
To modify this device, I targeted a reaction involving cholesterol as opposed to B-galactosidase. An excess of cholesterol creates plaque, which can build up in one's arteries. Atherosclerosis occurs when plaque build up obstructs blood flow, which can cause coronary artery disease, heart disease, and even fatal heart attacks. To help counteract this, early signs of atherosclerosis can potentially be identified and reversed by measuring the amount of cholesterol in a sample of blood plasma. A combination of reactions beginning with cholesterol esterase (pictured above) leads to a product of red quinoneimine dye and water. Thus, the same process with the ONP reaction can be performed with a green instead of blue LED, as green light absorbs the red dye's wavelength of light most efficiently. The concentration of cholesterol in a sample of one's blood plasma can then be determined by the amount of green light passing through the red solution.
• Performed enzyme reactions in cuvette for spectrophotometry testing.
• Designed and 3D printed the casing for all circuitry and photometry components.
• Modified existing Arduino code to measure Beta-galactosidase reactions.
• Identified alternative applications for blood plasma to detect atherosclerosis.
I worked in a team of three to design and create a spectrophotometer capable of testing concentrations of enzymatic reactions. Essentially, a cuvette containing a given solution is placed between an LED and photoresistor in a self-designed 3D printed container. The latter measures the amount of light passing through the substance in the cuvette, showing the concentration of the substance being analyzed and sending this data to a computer via Arduino and breadboard, which are also contained in their own 3D printed structure.
This section explains the science behind the experiment and the chemicals being inspected. For our project, we chose the Beta-galactosidase reaction which is a simple enzyme-substrate reaction. The enzyme B-galactosidase has an active site that breaks down a molecule known as ONPG when it is bound to the active site. This process occurs in a solution of water because this molecule is used in the hydrolysis of ONPG. The product of this reaction is the creation of ONP which is visibly yellow. The device monitors the B-galactosidase reaction through the use of a photoresistor. A blue LED is on one end of the cuvette, and a photoresistor on the other. Blue light is emitted into the sample of the ONPG and B-gal reaction, represented by the product ONP's yellow hue, because it absorbs this specific wavelength of light most efficiently. The fraction of light transmitted through the sample is measured by a photoresistor that sends data through the breadboard and Arduino to be converted into readable text. The breadboard contains the circuitry in order to achieve this. There is a resistor that measures the voltage drop from the electricity of the photoresistor, which is sent to the ports of the Arduino. The second resistor pictured is so the LED doesn't burn out (rated at 330Ω). The Arduino then computes the signal and sends it to the computer in the form of text to be read by the custom coded Arduino IDE program. These transmittance values can then be used to calculate the absorbance of the sample, which in turn can be used to measure the concentration of ONP in the solution.
To modify this device, I targeted a reaction involving cholesterol as opposed to B-galactosidase. An excess of cholesterol creates plaque, which can build up in one's arteries. Atherosclerosis occurs when plaque build up obstructs blood flow, which can cause coronary artery disease, heart disease, and even fatal heart attacks. To help counteract this, early signs of atherosclerosis can potentially be identified and reversed by measuring the amount of cholesterol in a sample of blood plasma. A combination of reactions beginning with cholesterol esterase (pictured above) leads to a product of red quinoneimine dye and water. Thus, the same process with the ONP reaction can be performed with a green instead of blue LED, as green light absorbs the red dye's wavelength of light most efficiently. The concentration of cholesterol in a sample of one's blood plasma can then be determined by the amount of green light passing through the red solution.
