Table 2.
Summary of bacterial viscoelastic parameters measured by MBFS under SFTV
| Sample | PAO1 early biofilm | wapR early biofilm | PAO1 mature biofilm | wapR mature biofilm |
|---|---|---|---|---|
| Instantaneous elastic modulus E1 (Pa) | 1.7 × 105 ± 8 × 104 | 6.2 × 104 ± 1.9 × 104 | 3.51 × 104 ± 1 × 102 | 1.5 × 104 ± 7 × 103 |
| Fold difference | 1 | 0.37 | 0.21 | 0.086 |
| Delayed elastic modulus E2 (Pa) | 1.1 × 106 ± 1 × 105 | 6.1 × 105 ± 4.6 × 105 | 5.1 × 105 ± 4.3 × 105 | 2.1 × 105 ± 5 × 104 |
| Fold difference | 1 | 0.56 | 0.47 | 0.19 |
| Viscosity η (Pa·s) | 2.3 × 105 ± 1.1 × 105 | 2.1 × 105 ± 1.7 × 105 | 1.0 × 105 ± 9 × 104 | 6.7 × 104 ± 2.5 × 104 |
| Fold difference | 1 | 0.92 | 0.43 | 0.29 |
| Retardation time τ (s) | 0.20 ± 0.08 | 0.33 ± 0.03 | 0.18 ± 0.02 | 0.32 ± 0.04 |
| Fold difference | 1 | 1.60 | 0.89 | 1.55 |
Means and standard errors of data shown from two independent experiments for each sample. Data were derived from nonlinear regression fit of creep curves using the enhanced Voigt Standard Linear Solid equation (see Materials and Methods). Each experiment consists of 10 replicate force plots under standard load force (10 nN), contact time (1 s), and ramp velocity (2 μm/s) to derive 10 creep curves for data extraction. Fold difference shown is relative to PAO1 early biofilm.