Specord 205 st

UV–VIS spectrophotometry (Specord 205 ST, Analytic Jena AG, Jena, Germany) was used for determination of the content of TT, DBCO, and amine groups. The molar absorption coefficient of ε(TT) = 10,300 L mol⁻¹ cm⁻¹ (λ_max = 305 nm) in methanol was used for determination of TT groups in the polymer precursors before hydrolysis (P1) or aminolysis (P5). In the case of DBCO groups, ε(DBCO) = 13,000 L mol⁻¹ cm⁻¹ (λ_max = 292 nm) in methanol was employed. The content of amine groups in polymer precursors P2, P4, and polymer-cluster conjugate POL6 was determined using a modified TNBSA assay as published earlier [37 (link)]. For P2 and POL6, the solution was prepared in borate buffer (0.1 M Na₂B₄O₇·10H₂O, pH 9.3) at the concentration of 2 mg mL⁻¹. An aliquot of 100 μL of this solution was mixed with borate buffer (875 μL) and 0.03 M solution of TNBSA in water (25 μL). The molar absorption coefficient ε (NH₂) = 17,200 L mol⁻¹ cm⁻¹ (λ_max = 500 nm) was used, and the absorbance was measured after 90 min of incubation. In the case of P4, a similar evaluation method was employed, but the sample was dissolved in a mixture of borate buffer and DMSO (9/1) due to the hydrophobic character of cholesterol moieties [30 (link)].

UV/visible absorption spectra were recorded on a spectrophotometer (Specord 205 ST, Analytic Jena AG, Germany). Garlicnin B1 was dissolved in acetonitrile/acetone/DMSO (6:3:1) at the concentration of 3 mg/mL, and the absorption spectra were recorded from 200 nm to 800 nm.