{
    "protocol": "The article does not provide a specific experimental protocol for the synthesis of hydrophilic polymers with functional groups.Photocurable hydrogels are synthesized by chemically reacting biomaterials with methacrylic anhydride or acryloyl chloride to introduce functional groups such as MA or DA. The process involves using a photoactivatable radical initiator like lithium pheny (2,4,6-trimethylbenzoyl) phosphinate (LAP) under light exposure of a certain wavelength. The unsaturated double bonds of these photosensitive groups polymerize with each other to form a crosslinking network.To synthesize hydrophilic polymers with functional groups, the following steps should be followed: 1. Prepare GelMA by hydrating gelatin and functionalizing it with methacrylic anhydride (MA). 2. Calculate the mass of GelMA after curing (x) and the double bond conversion (DBC). 3. Determine the degree of functionalization (DoF) using the ratio of amino acids containing amino groups in gelatin and the substitution rate of MA group. 4. Calculate the average molecular weight (M_ave) of the basic unit in GelMA using the proportions and molecular weights of amino acids. 5. Measure the concentration of P element using inductively coupled plasma mass spectrometry (ICP-MS) to find the number of initiator residues (N_ini-res). 6. Finally, calculate the Average Crosslinking Steps (ACS) using the formula: ACS = 2 * (N_DB / N_ini-res) - 1, where N_DB is derived from the values provided. Ensure thorough mixing and proper handling of all reactants and reagents throughout the process.The synthesis of hydrophilic polymers with functional groups involves crosslinking a liquid substance, which can be achieved by using reagents such as GelMA. To analyze the degree of crosslinking, the double bond content (DBC) is calculated using NMR spectrometry before and after crosslinking. Degradation of the crosslinked hydrogel can be performed with collagenase to obtain a liquid for measurement. The integral areas of characteristic peaks of carbon–carbon double bond in NMR spectra before and after crosslinking are used to evaluate the DBC, which is then used to calculate the degree of crosslinking (DGC) using the formulas provided: DBC = (1 - (A(after) / A(before))) x 100% and DGC = DBC x EDBC x 100%.The synthesis of hydrophilic polymers with functional groups involves the utilization of GelMA as an example. The main chain of GelMA is a peptide chain wherein crosslinking occurs through the interconnection of MA groups on the side chains. The degree of crosslinking (DSC) can be calculated using the formula: DSC = (N_(crosslinked bond) / (N_(peptide bond) + N_(crosslinked bond))) × 100%. The calculation of N_(peptide bond)* is given by N_(peptide bond)* = (ACS + 1) * (1 / DoF), and N_(crosslinked bond)* is calculated as N_(crosslinked bond)* = ACS. The final DSC formula is DSC = (DoF * ACS) / ((DoF + 1) * ACS + 1) × 100%."
}