Impact of Chitosan Molecular Weight and Attached
Non-Interactive Chains on the Formation of αLactalbumin Nanogel Particles
Juan Du, Young-Hee Cho, Ryan Murphy, and Owen Griffith Jones
50
α-lac
a-lac
CH113
HMW-CH
CH113-PEG
HMW-CH-PEG
CH8.9-PEG
LMW-CH-PEG
CH8.9
LMW-CH
CH76-PEG
MMW-CH-PEG
CH76
MMW-CH
40
ζ-potential (mV)
30
20
10
0
3
4
5
6
7
8
-10
-20
-30
pH
Figure S1. ζ-Potential of α-lactalbumin, chitosan (CH), or chitosan-graft-PEG (CH-PEG) as a function of solution pH.
1
a 240
CH76PEG
2
Intensity
190
5
10
140
90
40
3.7
3.9
4.1
4.3
4.5
4.3
4.5
pH
b
100
2
Intensity
80
CH76
5
10
60
40
20
0
3.7
3.9
4.1
pH
Figure S2. Intensity of scattered light at 90 degree scattering angle for mixtures of α-lactalbumin and (a)
CH76PEG or (b) CH76 at different r-value as a function of solution pH.
2
30
Turbidity (100 - %T)
25
20
15
10
5
0
CH113
CH113PEG
CH76
CH76PEG
CH8.9
Chitosan Type (MW, covalent-attachment)
r=
10
5
CH8.9PEG
2
Figure S3. Effect of r-value on turbidity of α-lac complexes heated at pH 4.8 for mixtures with CH113, CH76,
CH8.9, CH113PEG, CH76PEG, or CH8.9PEG.
3
200
rH
150
100
50
CH113
CH76
CH8.9
4
6
8
0
2
10
r
200
rH
150
100
50
CH113PEG
CH76PEG
CH8.9PEG
0
2
4
6
8
10
r
Figure S4 Effect of r-value on hydrodynamic radii of detected colloids within heated mixtures of αlactalbumin and (a) CH or (b) CH-PEG of different molecular weight at pH 4.8.
4
a
D2O
3,4,5,6
Ac
2
b
D2O
Ac
12,13
3,4,5,6
16
2
8,9
Figure S5. 1D Proton NMR spectra of (a) CH113 and (b) CH113PEG in 8% DCl/D2O (v/v) at concentrations of 5
mg/mL. Schematics of the representative chemical structures and peak assignments are given on the right.
5
Table S1. Turbidity of heated α-lac/CH76PEG mixtures at different pH and r-value 1 day after preparation
and 14 days after preparation.
Day 1
Day 14
100-T%
100-T%
4.3
1.37
0
4.8
5.59
2.95
5
5.3
10.26
6.67
5.8
15.67
10.26
4.3
1.60
0
4.8
3.39
1.37
2
5.3
6.46
2.50
5.8
7.53
3.62
Table S1 shows that turbidity of heated mixtures decreased ~30%–60% after 2 weeks of storage
(data at pH 4.3 was below noise threshold), possibly due to sedimentation of the largest nanogels in the
suspensions and/or separation of dust or bubbles from sample tubes during storage. However, the general
trend of turbidity between samples remained identical. This implied that mixtures with higher turbidity
on day 1 possessed nanogels of larger average size and/or number compared to sample mixtures of lower
turbidity, and this relation persisted following storage so that the same sample mixtures possessed
nanogels of larger average size and/or number after 2 weeks.
r
pH
6