*2.7. Statistical Analysis*

GraphPad Prism 7.0 (GraphPad Software, La Jolla, CA, USA) and Origin Pro Software were used in the analysis. Whenever applicable, data were described as means ± standard deviations, and significant values were determined using the analysis of variance (ANOVA) test.

#### **3. Results and Discussion**

#### *3.1. Peptide Conjugation Design*

The antimicrobial HDP IDR1018 was chosen for this study due to its promise as a therapeutic agent [38]. The well-known properties of IDR1018, including its ease and cost of synthesis as a linear peptide with 12 amino acid residues, as well as easily accessible sites for modifications, make it an excellent candidate for testing new modification approaches [17,19,38]. The original IDR1018 peptide sequence (Table 1) was modified by the addition of either PEG6 or a glucose moiety (GlcNAc) at the N-terminus to generate new derivatives, namely PEG6-IDR1018 and Glc-IDR1018, respectively. In PEG6-IDR1018, the PEG was attached to the amine terminus of the amino acid, valine, while in the glycosylation strategy, the GlcNAc was introduced into the peptide through O-linked glycosylation in an additional threonine residue. The resulting peptide conjugates are described in Table 1 while the chemical structures are shown in Scheme 1.

**Scheme 1.** IDR1018 conjugates, (**a**) the antimicrobial HDP IDR1018, (**b**) the pegylated derivative PEG6-IDR1018, where a carboxylated PEG chain was attached to the N-terminal of the peptide and (**c**) the glycosylated derivative, Glc-IDR1018, where N-acetyl glucosamine (GlcNAc) was attached to the hydroxyl (-OH) group of the amino acid threonine (T).
