The present disclosure features, inter alia, a cyclic multifunctional linker, including at least two cleavable moieties； at least two connecting chains connected to the at least two cleavable moieties to provide a cyclic structure； and at least two linking groups, each linking group being bonded at one end to a connecting chain and being located between two cleavable moieties, and each linking group having a second end configured to bond to crosslinkable moieties. In the cyclic multifunctional linker, each connecting chain has at least two ends, and at least two of the connecting chains are each connected at each end to a cleavable moiety.
