Table 1.
Comparison of the recent head-mounted and fully implantable wireless μ-ILED optogenetic tools.
| Property | Head Mounted |
Fully Implantable |
|||
|---|---|---|---|---|---|
| Reference | Kim et al., 2013; McCall et al., 2013 | Jeong et al., 2015; McCall et al., 2017 | Park et al., 2015b | Park et al., 2015a, 2016; Noh et al., 2018 | Shin et al., 2017 |
| μ -ILED | GaN (50 μm × 50 μm × 6.45 μm) | InGaN (220 μm × 270 μm × 50 μm) | |||
| Probe (thickness) | PET (20 μm) | PET + PDMS (80 μm) | PI (~ 30 μm) | PDMS (80–700 μm) | PI (80–130 μm) |
| Encapsulation material (thickness) | SU 8 (2 μm) | SU 8 (2 μm) | SU 8 (2 μm) | Parylene C (6 μm) | Parylene C (5 μm) |
| Power | Wireless RF scavenging | LiPo batteries | Photovoltaic cells | RF capacitive coupling | Magnetic resonant coupling |
| Control (Frequency) | Far-field RF (910 MHz) | Infrared (38 kHz) | Far-field RF (1.6–2.5 GHz) | Far-field RF (1.8–3.2 GHz) | Near-field RF (13.56 MHz) |
| Range | ~1 m | ~2 m | ~0.2 m | ~0.2 m | ~0.1 m |
| Weight | 2 g | 1.8 g | 70 mg | ~16–220 mg | ~30 mg |
| SAR | 0.77 mW/cm2 | No impact | < 18 mW/kg | ~ 69 mW/kg | < 20 mW/kg |