{
    "protocol": "Free-radical polymerization of hydrogel precursors, which consist of monomers, crosslinkers, and initiators, is used for hydrogel preparation. After curing, incubate the hydrogel in excess deionized (DI) water for several hours to days, regularly replenishing the DI water, to remove unreacted monomers and initiators.To synthesize hydrophilic polymers with functional groups, cyanoacrylate monomers are used. These monomers diffuse into the hydrogel polymer network and polymerize through anionic polymerization, forming polycyanoacrylate chains within the network. This process involves topological entanglement with the existing hydrogel polymer matrix. It is essential to ensure that the thickness of the hydrogel coating is significantly greater than the diffusion depth of cyanoacrylates, which has been observed to reach approximately 10 micrometers, to maintain the integrity of the hydrogel during the bonding process."
}