TABLE II.
Overview of longevity of the surface layers based on the current surface layer stability study.
| Sample namea | Unaltered, lifetime (UL) | Functional, lifetime (FL) | Method of evaluation | Cause of degradation |
|---|---|---|---|---|
| h-PLGAp | 3 days | >21 days | DLS (UL and FL) | Hydrolysis |
| h-PLGAf | 1 day | >14 days | F At. % from XPS (UL) AFM and XPS (FL) | Hydrolysis and de-wetting |
| a-PCLf | 14 days | >21 days | XPS and CA (UL), C/O ratio from XPS (FL) | Unknown |
| s-PCLf | <3 days | <3 days | XPS and CA (UL and FL) | Mohr's salt |
| a-PCLd | 14 days | >21 days | XPS and CA (UL), C/O ratio from XPS (FL) | Unknown |
| s-PCLd | <3 days | <3 days | XPS and CA (UL and FL) | Mohr's salt |
| h-PCLs | 14 days in water, >21 days in PBS | >21 days | XPS (UL), F/C ratio from XPS (FL) | Hydrolysis |
| L-PCLs | >14 days | >21 days | XPS (UL), N/C ratio from XPS (FL) | Unknown |
a
Prefix denotes modification and subscript the substrate, i.e., prehydrolyzed samples are denoted “h-” prefix, AEMA grafted samples are denoted “a-” prefix, SPA grafted samples are denoted “s-” prefix, L-lysine(Boc)-grafted samples are denoted “L-” prefix, particle substrates are given a “p” subscript, film substrates are given “f” subscript, disk substrates are given “d” subscript, and scaffolds are given “s” subscript.