## 3 Results and Discussion  
In the first phase of the present work, we designed a set of sulfur-functionalized derivatives of d-glucose, C-glucose **1** and L-glutamine (Figure 3) in order to have the suitable compounds for the preparation of the corresponding gold nanoparticles (Figure 4) [54; 64]. The role of the d-glucose derivative O-(5\({}^{\prime}\)-thiopethyl)-\(\beta\)-D-glucopyranoside (compound **3**, **Glc5 SH**), synthesized following a well-established protocol [65; 66], was to improve the water dispersibility of the nanoparticles, since compound **1** showed low water solubility (approximately 0.5 mg/mL). Furthermore, **Glc5 SH** was also selected as an \"inner component\" [51; 66]. It should be noted that while ligands **2**, **4** and **5** have a long and amphiphilic linker to impart flexibility and assist in the water dispersibility of the final AuNPs, **Glc5 SH** has a short and hydrophobic linker to ensure the rigidity of the nanoparticle and allow the above-mentioned ligands to protrude from the gold surface. **Glc5 SH** should thus assist the multivalent effect of the other thiol-ending ligands, rather than interfering with their biological effects, since SGLT1-mediated anti-inflammatory effects are observed only with huge amounts of orally administered d-glucose. Firstly, we designed the synthetic route of the derivatives considering the attachment of a suitable spacer/linker bearing a terminal thiol group. This linker ensured the correct spatial separation between the core of the gold nanoparticle and the \"active component\" (C-glucose **1** or L-glutamine), which is necessary for the interaction of the bioactive molecules with the target receptor. The linker that we chose was composed  
Figure 4: General structure of the designed nanoparticles: AuNPs decorated with the “active components” C-glucose **2** and/or L-Gln **4** or **5**. The density of the “active components” can be modulated by varying their molar equivalents with respect to the “inner component” (**Glc5 SH**). Figure 3: Sulfur-functionalized ligands for the preparation of the AuNPs. of a tri(ethyleneglycol) (TEG) chain and a five-carbon atom (C\({}_{5}\)) spacer. Ethylene glycol polymers are extensively used in the pharmaceutical industry for their low toxicity, excellent solubility in aqueous media, resistance to non-specific protein adsorption and potential limited immunogenic and allergenic effects [67; 68]. PEGylation is an important and emerging aspect in the drug delivery field; the conjugation of PEG to drugs has a positive impact on the pharmacokinetic and pharmacodynamic profile of the molecule to which it is conjugated. Moreover, polyethylene glycol (PEG) represents an inert polymer and is not metabolized. From a synthetic point of view, the insertion of a PEG chain on small molecules or drugs as well as biomacromolecules is now a relatively simple chemical transformation owing to numerous differently functionalized and commercially available PEG chains, and thanks to the development, over the last few decades, of many chemical (bio)orthogonal ligation strategies. For example, in a previous work, we developed a synthetic strategy to obtain heterobifunctionalized (poly)ethylene glycol chains for use as chemical tools in the modification of bioactive molecules and bio(macro)molecules [69]. The monofunctionalization of the triethyleneglycol linker with a pentenyl chain allowed for the introduction of a terminal double bond, which was exploited for the insertion of a sulfur-containing group, through a thiol-ene coupling (TEC) reaction [70]. Several synthetic procedures allow for the conversion of a terminal alkene into a thioether linkage, for example, using a Michael addition reaction between a thiol compound and a \(\alpha\),\(\beta\)-unsaturated carbonyl compound or exploiting a radical mechanism, as in the case of AIBN-catalyzed reactions. We decided to rely on a radical photoinitiator, called 2,2-dimethoxy-2-acetophenone (DPAP), which allows the thiol-ene reaction to occur in a faster and simpler fashion.