A hyperbranched aliphatic polyether with hydroxyl end groups was produced from glycerol carbonate (4-hydroxymethyl-1,3-dioxolan-2-one)—the benign monomer obtained from renewable starting materials: glycerol and dimethyl carbonate. Anionic polymerization of glycerol carbonate, which proceeds with simultaneous decarboxylation, was performed using partially deprotonated trimethylolpropane (TMP) as an initiator. Pendant hydroxyl groups facilitate the ring-opening multibranching polymerization leading to a hyperbranched polyether. ¹³C NMR analysis of the polymerization products confirmed the presence of linear, dendritic, and terminal repeating units. MALDI-TOF mass spectrum analysis confirmed the presence of TMP and glycerol core containing branched structures as well as a relatively small amount of macromolecules with cyclic groups. The polymers were soluble in water, THF, methanol and DMSO.

Catalytic nanomaterials, widely used as substitutes of peroxidase, exhibit unique properties, which are unattainable for native enzymes. However, their activity is usually examined by means of substrates developed and methods standardized for horseradish peroxidase (HRP). The aim of the presented work was to determine the scope of usefulness of chromogenic substrates for gold nanoparticle (AuNP) activity studies under conditions which significantly extend beyond the activity range of a native HRP. The applicability of chromogens such as 3,3′5,5′-tetramethylbenzidine (TMB), o-phenylenediamine (OPD), 2,2′-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) beyond the typical range of pH, and for the samples of high concentration of hydrogen peroxide was examined. The conducted research confirmed the usefulness of ABTS and TMB in acidic media (pH 2.5–3.5). At the same time, potential interferences from chloride anion, unobservable for HRP-based assays, were indicated. Moreover, a number of potentially useful hints concerning relations of concentration of substrates and catalyst for aromatic amine oxidation (TMB and OPD) were proposed. By increasing the concentration of chromogens and thanks to assuring the relatively low conversion of the reaction, the stability of TMB and OPD oxidation product was improved even in acidic media. The comparative studies of H₂O₂ affinity to the surface of AuNPs in the presence of various hydrogen donors underlined the superiority of phenolic compounds over aromatic amines and ABTS in the case of the samples of relatively low H₂O₂ concentration. This work highlights some improvements in the methods of HRP-like activity characterization of NPs. It provides a critical analysis of the major challenges, which may emerge in a case of bioanalytical assays employing the catalytic nanoparticles as labels.