Table 2.
The wavenumbers (cm−1) associated with the respective functional groups as confirmed by FTIR [31,32,33,35,36,37,38,39].
| Functional Group | Wavenumber (cm−1) | Interpretation |
|---|---|---|
| O-H | 3297.30 | Hydroxyl groups in phenolic compounds |
| C-H | 2918.90 | Methyl and methylene groups of lipids |
| C=O | 1789.10 | Carbonyl groups |
| C=C | 1674.00 | Alkene groups |
| N-H | 1595.40 | Amide groups in proteins or peptides |
| C-O-C | 1258.00 | Ester and ether linkages |
| O-H | 3268.69 | Incorporation of phenolic compounds from GBE |
| C-H | 2915.90, 2859.87 | Aliphatic chains in sphingomyelin and cholesterol |
| C=O | 1788.67 | Hydrogen bonding, successful encapsulation |
| C-O | 1251.53 | Presence of esters and ethers from GBE |
| N-H | 3094.28 | Conjugation of PLL to SLNPs |
| C-H | 2912.68 | Aliphatic chains in lipids and PLL |
| C=O | 1742.15 | Conjugation of PLL to GBE |
| C-N | 1305.66 | Amine groups from PLL |
| O-H | 3353.03 | Hydration of lipid components |
| N-H | 3148.81, 3090.19 | Presence of sphingomyelin within SLNPs |
| C-H | 2903.17 | Aliphatic chains in cholesterol and sphingomyelin |
| C=O | 1744.75 | Ester groups in the SLNP matrix |
| N-H | 3096.43 | Interaction between PLL and the lipid matrix |
| C=O | 1742.01 | Electrostatic interactions between lipids and PLL |