uploaded soluton but ddnt undertstand how dilute number is equal to 2 and how did he find 26.2 and 23.8. can you show me calculaton please?

) Assume that you set-up an experiment by seeding Human Mesenchymal Stem Cells (hMSC) on the nanofibers. You have 3 groups and 4 characterization techniques after cell seeding. Experiments should be performed 3 times for the same analysis on the same sample. The concentration of the cells is 3x104 cells/cm2 and the volume of cell suspension in each NF is 50L. Each nanofiber is circular with diameter of 12mm. For cell seeding, cell suspension was homogenized carefully mixed 100 l of cells with 9.9 ml of PBS before counting. Then 50l of cells with 50 l of trypan blue were mixed. 75 cells were counted in 5 squares of a hemocytometer

a) Please set up an experiment by calculating (5pts)

i) total sample number

ii) total sample volume

iii) cell number in each sample

iv) cell number in total volme

b) What is the concentration of cells in original undiluted culture? (5pts)

c) How much cell suspension and medium should be mixed for each sample and total sample? (5pts)

ANSWER;

a)

i) Total sample number will be 36

(3 groups * 4 characterization = 12 sample; 3 time of each experiment = 12*3 = 36 samples)

ii) Total sample volume will be 1.8 ml or 1800 ul.

(36 NF*50ul = 1.8 ml)

iii) cell number in each sample= 3.93*10⁴ cells.

12 mm diameter =1.2 cm diameter or 0.6cm radious)

(area of each circular NF= pi*r² ; so, 22/7*0.6cm² = 1.13cm²)

3*10⁴ cells/cm²; so, 3*10⁴ cells* 1.13cm² = 3.93*10⁴ cells / sample or NF

iv) Cell number in total volume = 1.41*10⁶ cells.

(3.93*10⁴ cells / 50 ul * 1.8 ml = 1.41*10⁶ cells)

b) If we consider cell count of 75 in 5 squares of haemocytometer then,

75*2 (dillution factor)*10⁴ cells / ml

so, 1.5*10⁶ cells / ml will be the concentration in original undiluted culture.

* Note - As per my knowledge only four side squares of haemocytometer was considered for cell counting, not five squares. After counting the number of cells in four squares, average was calculated and multiplied with the dillution factor followed by multiplication with 10⁴.

c) Based on my calculation

For each sample, 26.2 ul cell suspension + 23.8 ul medium will be used. (Total 50 ul).

For total sample, 943.2 ul (26.2*36 ul) cell suspension + 856.8 ul (23.8*36 ul) medium will be used. (Total 1.8 ml)

3) Draw a cartoon that clearly shows how a colorimetric paper-based glucose biosensor works