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A new sensor to detect bloodborne biomarkers is in development. The sensor uses enzymes immobilized on the surface of a flat strip (0.1cm X2cm) of polymer material to collect the biomarkers for increased detection. The enzymes rapidly convert the biomarkers into a secondary product that can be detected more easily. In an experiment, you collect blood from a patient that contains the biomarker and gently flow it over the sensor material at a velocity of 2 cm min". The flow is parallel to the long axis of the strip and the temperature is maintained at 37°C.

If the diffusivity of the biomarker in blood was determined to be 5.87 X 10^6 cm^2/s, what is the mass transfer coefficient for this process?

Your data indicates that 0.023 milligrams of biomarker were collected in 1 hour. Based on this measurement, what is the biomarker concentration in the blood?

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Related questions

You are designing a medical device to collect

Carcinoembryonic Antigen (CEA, MW = 180,000 g

mol^-1), a tumor marker, from patients in order to create a personalized cancer vaccine. In this medical device, the cellular components of the blood are removed from the plasma. The plasma then flows into an extraction chamber. Within this chamber, the fluid flow divides into 48,000 10-cm long tubes with an inside diameter of 175 um. The surface of each tube is coated with a material that very rapidly adsorbs CEA. Plasma containing 6.1 ug m1^-1 of CEA flows into the chamber at 125 ml min^-1. Assume that the fluids are at body temperature (37°C). The viscosity and density of water at 37°C are 0.691 cP and 0.993 g/ cm^3, respectively.

A) Estimate the diffusivity of CEA within the extraction chamber?

A new implantable drug delivery device is being developed in your lab. The device prototype is a very thin strip (0.1mm × 1mm × 15mm) of polymer coated on both sides with 22 milligrams of solid drug particles. To test the drug delivery profile, you

"implant the device by suspending it in a homogenous model fluid that has following

properties: viscosity = 0.0018 Pa.s, density = 1.32 g

cm^-3, temperature = 37°C. The diffusivity of the drug is estimated to be 2.113×10^-6 cm^2/S.

After 15 minutes, what do you expect the concentration of the drug to be at 1 mm from the device?

Do Enzymes Physically Attach to Their Substrates?
 
When scientists first began to examine the chemical activities of organisms, no one knew that biochemical reactions were catalyzed by enzymes. The first enzyme was discovered in 1833 by French chemist Anselme Payen. He was studying how beer is made from barley: First, barley is pressed and gently heated so its starches break down into simple two-sugar units; then yeasts convert these units into ethanol. Payen found that the initial breakdown requires a chemical factor that is not alive and that does not seem to be used up during the process-a catalyst. He called this first enzyme diastase (we call it amylase today).
 
Did this catalyst operate at a distance, increasing the reaction rate all around it, much as raising the temperature of nearby molecules might do? Or did it use physical contact, actually attaching to the molecules whose reaction it catalyzed (its "substrate")?
 
The answer was discovered in 1903 by French chemist Victor Henri. He saw that the hypothesis that an enzyme physically binds to its substrate makes a clear and testable prediction: In a solution of substrate and enzyme, there must be a maximum reaction rate. When all the enzyme molecules are working full tilt, the reaction simply cannot go any faster, no matter how much more substrate you add to the solution. To test this prediction. Henri carried out the experiment whose results you see in the graph, measuring the reaction rate (V) of diastase at different substrate concentrations (S).
 
Analysis
1. Making Inferences As S increases, does V increase? If so, in what manner-steadily, or by smaller and smaller amounts? Is there a maximum reaction rate?
2. Drawing Conclusions Does this result provide support for the hypothesis that an enzyme binds physically to its substrate? Explain. If the hypothesis were incorrect, what would you expect the graph to look like?
3. Further Analysis If the smaller amounts by which V increases are strictly the result of fewer unoccupied enzymes being available at higher values of S, then the curve in Henri's experiment should show a pure exponential decline in V-mathematically, meaning a reciprocal plot (1/V versus 1/S) should be a straight line. If some other factor is also at work that reacts differently to substrate concentration, then the reciprocal plot would curve upward or downward. Fill in the reciprocal values in the table to the right, and then plot the values on the lower graph (1/S on the x axis and 1/V on the y axis). Is a reciprocal plot of Henri's data a straight line?

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