## 3 Materials and Methods
### Enzyme Ring-Opening Polymerization of \(\varepsilon\)-Caprolactone and Poly(ethylene glycol)  
The enzyme ring-opening polymerization (e-ROP) reactions of CL and PEG were carried out according to our previously described method with some modifications [76; 77; 78]. Before the reaction, CL, PEG, and CA were dried under a vacuum at room temperature for 1 h. Next, 0.05 mol CL was placed in a three-neck flask equipped with a stirrer and thermometer (under an argon atmosphere), and 20 mL of toluene was added. The mixture was stirred at 80.0 \({}^{\circ}\)C for 4 h. Next, an appropriate amount of PEG and CA (500 mg) was added to the mixture. Stirring was continued at 80.0 \({}^{\circ}\)C for 72 h under an argon atmosphere. After this time, the enzyme was filtered off. Toluene was removed by evaporation under reduced pressure at room temperature. Next, the cooled product was dissolved in DCM and extracted with cold methanol and distilled water.  
The structures of the synthesized copolymers were evaluated using \({}^{1}\)H and \({}^{13}\)C NMR techniques (Figures S1 and S2, Supplementary Materials). The spectra were recorded on an Agilent Technologies 400 MHz (Santa Clara, CA, USA) spectrometer. The IR spectra were measured from KBr pellets (PerkinElmer spectrometer, Great Britain) (Figure S3, Supplementary Materials).  
Spectroscopy data of obtained copolymers:  
The \({}^{1}\)H NMR (CDCl\({}_{3}\)): 1.40 ppm (-CO-CH\({}_{2}\)-CH\({}_{2}\)-CH\({}_{2}\)-CH\({}_{2}\)-CH\({}_{2}\)-O-), 1.64 ppm (-CO-CH\({}_{2}\)-CH\({}_{2}\)-CH\({}_{2}\)-CH\({}_{2}\)-CH\({}_{2}\)-O-), 2.30 ppm (-CO-CH\({}_{2}\)-CH\({}_{2}\)-CH\({}_{2}\)-CH\({}_{2}\)-CH\({}_{2}\)-O-), 3.63 ppm (-CH\({}_{2}\)-CH\({}_{2}\)-O-), 4.05 ppm (-CO-CH\({}_{2}\)-CH\({}_{2}\)-CH\({}_{2}\)-CH\({}_{2}\)-CH\({}_{2}\)-O-), 4.21 ppm (-CH\({}_{2}\)-CH\({}_{2}\)-O-), CH\({}_{2}\)-CH\({}_{2}\)-O-Cap-); the \({}^{13}\)C NMR (CDCl\({}_{3}\)): 24.62 ppm (-CO-CH\({}_{2}\)-CH\({}_{2}\)-CH\({}_{2}\)-CH\({}_{2}\)-CH\({}_{2}\)-O-), 25.57 ppm (-CO-CH\({}_{2}\)-CH\({}_{2}\)-CH\({}_{2}\)-CH\({}_{2}\)-CH\({}_{2}\)-O-), 28.39 ppm (-CO-CH\({}_{2}\)-CH\({}_{2}\)-CH\({}_{2}\)-CH\({}_{2}\)-O-), 32.36 ppm (-CO-CH\({}_{2}\)-CH\({}_{2}\)-CH\({}_{2}\)-CH\({}_{2}\)-OH-) end groups, 34.16 ppm (-CO-CH\({}_{2}\)-CH\({}_{2}\)-CH\({}_{2}\)-CH\({}_{2}\)-O-), 62.57 ppm (-CO-CH\({}_{2}\)-CH\({}_{2}\)-CH\({}_{2}\)-CH\({}_{2}\)-CH\({}_{2}\)-OH-) end groups, 63.49 ppm (-CH\({}_{2}\)-CH\({}_{2}\)-CH\({}_{2}\)-O-CH\({}_{2}\)-CH\({}_{2}\)-O-), 64.18 ppm (-CO-CH\({}_{2}\)-CH\({}_{2}\)-CH\({}_{2}\)-CH\({}_{2}\)-CH\({}_{2}\)-O-), (-CH\({}_{2}\)-CH\({}_{2}\)-OCH\({}_{2}\)-CH\({}_{2}\)-O-CO-), 70.60 ppm (-CH\({}_{2}\)-CH\({}_{2}\)-O-), 173.57 ppm (-CO-CH\({}_{2}\)-CH\({}_{2}\)-CH\({}_{2}\)-CH\({}_{2}\)-CH\({}_{2}\)-CH\({}_{2}\)-CH\({}_{2}\)-O-).  
FTIR (KBr, cm\({}^{-1}\)): 2941 (v\({}_{\rm as}\)CH\({}_{2}\)), 1722 (vC=O), 1236 (vC-O).  
The \(M_{\rm n}\) and \(D\) index values of the synthesized copolymers were determined using the GPC technique. The measurements were carried out on a Malvern Viscotek GPCMax TDA 305 (Malvern Panalytical, Malvern, UK) chromatograph equipped with a [PERSON] mixed-bed column ([PERSON], Mansfield, MA, USA). The mobile phase flow (DCM) was set to 1.0 mL/min, and the column temperature was set to 30 \({}^{\circ}\)C. The system was calibrated using polystyrene standards.