## 3 Results  
**Study 1. Assess effect of PEMF on FLS wound closure in a 2D injury model. **  
A scratch assay using a monolayer of bovine FLS was used to determine if PEMF stimulation could promote cell migration and wound closure in vitro. FLS migration rates were calculated by measuring cell coverage into the defect space at defined time points following initial cruciform injury (Figure 5A-H). Compared to untreated controls, a gradual improvement in cell migration was observed in FLS treated with PEMF stimulation with a significant increase in wound closure percentage at 24 h (\(p\) = 0.0319) and 48 h (\(p\) = 0.0007) following injury (Figure 5I). At the 24 h timepoint, FLS exposed to PEMF exhibited increased wound closure with a percent difference of 23% compared to controls. The percent difference in wound closure remained consistent at 48 h following injury with a 20% increase in PEMF treated groups. **Study 2. Evaluate the effect of DC EF stimulation on FLS migration within a collagen hydrogel matrix via galvanotaxis. ** \begin{table}
\begin{tabular}{c c c} \hline
**Gene** & **FWD Primer Sequence** & **REV Primer Sequence** \\ \hline GAPDH & GTC ATC ATC TCT GCA CCT TCT G & GGA GGC ATT GCT GAC AAT CT \\ \hline COL10A1 & CTG CCC GAG GAC TTT GTA A & GGG TAA GCT TTG GAG AGG ATA \\ \hline COL2A1 & GGC CTC TCT GCT TCT TGT AA & CTA GAG TGA CTG GGA TTG GAA AG \\ \hline COL1A2 & TCC AAGA GCTC TAG GAA GAA & CTT GGT TAG GGT CAA TCC AGT AG \\ \hline COL11A2 & CCT GGA TGA GGA AGT CT TGA G & CTT CTG GTC ACA GGA TTC GTA G \\ \hline ACAN & CCT CAG GGT TTC CTG ACA TTA G & GCT CAG TCA CGC CAG ATA TT \\ \hline COL3A1 & TGG TAT TCC TGG GCG AAA TG & CCA CCA GTA GGA CAT GAT TCA C \\ \hline COL1A1 & CAG ACT GGC AAC CTC AAG AA & TAG GTG ACG CTG TAG GTG AA \\ \hline COL4A1 & CAC GGC TAC TCT TTG CTC TAC & GAA GGG CAT GGT ACT GAA CTT \\ \hline \end{tabular}
\end{table} 
Table 1: qPCR Primer Sequences for cartilage and synovium markers. ACAN: Aggrecan, COL1: collagen type I, COL2: collagen type II, COL3: collagen type III, COL4: collagen type IV, COL5: collagen type V, COL10: collagen type X, COL11: collagen type XI, GAPDHH (housekeeping gene). Figure 5: Representative images from in vitro wound healing assay demonstrating FLS migration into the cell-free region (blue) for (**A–D**) control and (**E–H**) PEMF treated samples (Scale bar = 100 \(\upmu\)m). (**I**) Quantified percent wound closure of control and PEMF exposed FLS at 12, 24, and 48 h following initial cruciform injury (\(n\) = 6 per treatment condition). Following 3 h of DC EF application, photomicrograph analysis of the FLS-seeded collagen hydrogels revealed a significant increase of 79% in overall migration speed (2.5 \(\upmu\)m/h) compared to untreated controls (1.4 \(\upmu\)m/h) (Figure 6A; \(p<0.001\)). A 3.6-fold increase in average incremental migration speed was observed in FLS under DC EF stimulation (6.9 \(\upmu\)m/h) compared to controls (1.9 \(\upmu\)m/h) following each 10 min acquisition interval (Figure 6B; \(p<0.001\)). Directed velocity of FLS migration within the hydrogels toward the cathode was significantly higher with galvanotaxis EF stimulation versus controls (1.9 and 0.5 \(\upmu\)m/h, respectively) (Figure 6C; \(p<0.001\)). Monitoring the path of each individual cell revealed that the mean FLS migration angle was 46\({}^{\circ}\) for the DC EF exposed hydrogels compared to 156\({}^{\circ}\) for the untreated control group (Figure 7). **Study 3. Apply DC EFs via galvanotaxis to synovium explants in order to evaluate migration of synovial repair cells within a 3D cartilage defect model. **  
Figure 6: Effect of DC EFs on (**A**) overall speed, (**B**) incremental speed, and (**C**) directed velocity of bovine FLS within a 3D collagen hydrogel (* \(p<0.001\)). Parameters were determined by following the path of individual cells for both CTL (\(n=20\) cells) and EF treated (\(n=24\) cells) groups. Figure 7: Individual migration paths for (**A**) CTL (\(n=20\)) and (**B**) EF (\(n=24\)) treated FLS within the 3D collagen gel.