TABLE I.
In vivo mechanical and material properties of brain tissue
| Punch Type | 100 μm Ø flat punch |
200 μm Ø flat punch |
200 μm Ø sharp |
||||
|---|---|---|---|---|---|---|---|
| Insertion Rate | 822 μm/s | 104 μm/s | 11 μm/s | 822 μm/s | 104 μm/s | 11 μm/s | 822 μm/s |
|
Fmax bulb (μN) |
732.4±244.1 (n = 9) |
323.3±67.1 (n = 4) |
427.0±74.9 (n = 6) |
1609.0±174.1 (n = 3) |
1091.1±62.8 (n = 2) |
1024.3±124.1 (n = 3) |
790.8±10.1 (n = 3) |
|
Fmax cortex (μN) |
833.7±55.1 (n = 6) |
564.4±58.7 (n = 4) |
519.4±52.7 (n = 7) |
2481.7±193.1 (n = 2) |
1700.9±142.4 (n = 3) |
1270.8±105.2 (n = 3) |
1358.6±107.7 (n = 3) |
| Fcrit bulb * (μN) | 605.0±70.9 (n = 9) |
201.5±60.0 (n = 4) |
317.9±105.2 (n = 6) |
1344.6±293.9 (n = 3) |
794.8±38.9 (n = 2) |
590.2±31.4 (n = 3) |
----- |
|
Fcrit cortex * (kPa) |
464.0±63.6 (n = 6) |
321.0±55.0 (n = 4) |
328.0±68.2 (n = 7) |
1092.6±166.2 (n = 2) |
1235.8±227.9 (n = 3) |
1174.9±104.8 (n = 3) |
----- |
|
E bulb (kPa) |
13.0±3.6 (n = 9) |
5.5±1.1 (n = 4) |
5.2±0.9 (n = 6) |
10.4±1.8 (n = 3) |
4.6±0.2 (n = 2) |
3.4±0.8 (n = 3) |
----- |
|
E cortex (kPa) |
10.5±0.9 (n = 6) |
6.1±0.3 (n = 4) |
4.9±0.7 (n = 7) |
7.4±0.7 (n = 2) |
5.4±0.8 (n = 3) |
5.2±0.2 (n = 3) |
----- |
| ΔFf/Δδ bulb (μN/mm) |
191.9±43.7 (n = 3) |
58.2±23.6 (n = 2) |
172.7±68.8 (n = 3) |
168.2±10.2 (n = 3) |
154.1±22.6 (n = 2) |
461.4±143.7 (n = 2) |
194.3±8.9 (n = 3) |
| ΔFf/Δδ cortex (μN/mm) |
213.9±38.9 (n = 3) |
279.3±28.3 (n = 3) |
300.8±110.8 (n = 3) |
269.7±65.4 (n = 3) |
473.2±37.2 (n = 3) |
721.0±250.4 (n = 3) |
556.3±77.9 (n = 3) |
| ΔFcut/Δδ bulb (μN/mm) |
----- | ----- | ----- | ----- | ----- | ----- | 349.4±23.4 (n = 3) |
| ΔFcut/Δδ cortex (μN/mm) |
----- | ----- | ----- | ----- | ----- | ----- | 321.8±43.0 (n = 3) |
Average values and standard errors are presented. (Ø = diameter, bulb = olfactory bulb, cortex = cerebral cortex, Fmax = maximum force, E = tissue modulus, Fcrit = force at which probe penetrates the tissue, ΔFf/Δδ = rate of change frictional force with respect to penetration depth, and ΔFcut/Δδ = rate of change of cutting force of the tissue with respect to penetration depth).
*
Not included in statistical analysis