In week 2, our group did a deeper research on characteristics of tumor cells and previous research projects on early diagnosis of cancer. Some characteristics of cancer cells that can be taken advantage of in diagnosis are: 

1.  Enhanced Permeability and Retention. This is the ability to absorb and retain particles in the body; healthy cells don't absorb as many particles as tumor cells. 
2.  Producing Proteins that can be detected in the blood (like Prostate-specific antigen produced by prostate gland)
3.  Many kinds of cells shed microvesicles into blood, but the amount by tumor cells is substantial.
4.  The presence of particular genes related to cancer in fluids produced from the body.

We also brainstormed on different methods that can be used to diagnose early cancer. Here are the top three of strategies:

1:Using magnetic field to attract induced cancer cell-binding magnetic nanoparticles and extracting them with a syringe 

Figure 1: A drawing of extracting tumor cells from an arm vessel using a magnet, magnetic nanoparticles and a syringe 

Merits of this strategy: 

• Moderate related risks
• Moderate invasiveness
• Nanoparticles which bind to cancer cells have  been made
• Magnetic field strength can be easily regulated to avoid collapse of the vessels
• Magnetic field strength and suction strength to do the job can be determined by designing and testing.
• Increased chance of detecting cancer at an early stage

2. Continuous extraction of blood flow, with immediate filtering (dialysis)

Figure 2: A drawing of extracting tumor cells by filtering them outside the body

Merits of this strategy:

• Remove the need for balancing magnetic strength and suction strength with the blood stream
• Dialysis operation have been designed, it would be the manipulation of an existing system to meet our need

3. Centrifugation of blood extracted to separate tumor cell-bound nanoparticles. This would require a lot of blood.

Figure 3: A drawing of centrifugation to remove tumor-bound nanoparticles.

Merits of this strategy:

• It would provide enough cells to test to determine whether the cells are cancerous.
• Drawing the blood from the body to test it outside is easier than extracting the blood using syringe, since there is no need to balance the suction pressure with blood pressure.

We also brainstormed on functional requirements and specifications for our design. The table below shows them.

Table 1: Functional requirements and parameters to check if they are met.

Functional Requirements	Design Parameters
List of independent functions that the design is to accomplish	Specific way to know that the FR has been met (typically numerical)
Attract Nanoparticles in the Bloodstream	There must be more nanoparticles at the attractive force application site than remain circulating in the bloodstream model.
Shape Must Provide Optimal Magnetic Field	The shape of the grouping of nanoparticles, due to the attractive force, must be circular. Strength of magnetic field is less than suction force of needle used for extraction.
Material Must be Compatible with the Magnetic Material in the Nanoparticles	Movement towards the magnet is observed when the magnetic nanoparticles are placed within 1 cm of the device.
The Device Must be Easily Manipulated and Proportional to Medical Requirements	Device diameter, should be a little bit larger than that of the target blood vessel( blood vessel in the arm surface)- for instance, Median antebrachial vein.