Fig. 5

(a) Size distribution graphs of (i) FL-cHy-NPs and (ii) HK-cHy-NPs showing the average diameter of the NPs and polydispersity index (PDI). The inset figure shows the visual appearance of the colloidal solution of the same cHy-NPs before (1) and after (2) crosslinking. (b) Figures showing TEM images of developed cHy-NPs confirm their spherical shape and intact integrity (i) TEM Image of the FL-cHy-NPs (scale 500 nm) and inset; enlarged NP. (ii) TEM image of the HK-cHy-NPs (scale 500 nm) and inset; enlarged NP. (c) The stability of synthesized FL-cHy-NPs and HK-cHy-NPs in the colloidal solution stored at 4° C: (i) the average size and (ii) PDI values of the cHy-NPs at 0, 7, 21, 36 and 60 days of storage. The means of each sample were compared using one-way ANOVA and using Dunnett multiple comparison post hoc test with a family-wise alpha threshold confidence level of 0.05 (95% confidence interval). Here, all the values are showing no difference (ns; p > 0.05) with each other suggesting the stability of the cHy-NPs at different time points. (d) Effect of various cryoprotectants on the size and PDI of the NP formulations after lyophilization. The graphs are showing effect of cryoprotectants on the (i) size of FL-cHy-NPs, (ii) PDI values of FL-cHy-NPs, (iii) size of HK-cHy-NPs, and (iv) PDI value of HK-cHy-NPs. The data were analyzed using two-way ANOVA and the group sample means were compared with the blank sample (non-lyophilized) by Dunnett’s multiple comparison post-hoc test. The family-wise alpha threshold confidence level was adjusted to 0.05 (95% confidence interval) during the analysis. Here, all the values are showing no difference (p = ns > 0.05) with each other suggesting the optimal concentration of the respective cryoprotectant to stabilize the NP preparation (size and PDI).