Dual-crosslinked alginate hydrogels with a high Ca²⁺ content were successfully prepared, which extended their properties, and showed potential application as a skin strain sensor.

Over the decades, widespread advances have been achieved on nanochannels, including nanochannel-based DNA sequencing, single-molecule detection, smart sensors, and energy transfer and storage. However, most interest has been focused on the contribution from the functional elements (FEs) at the inner wall (IW) of nanochannels, whereas little attention has been paid to the contribution from the FEs at the nanochannels’ outer surface (OS). Herein, we achieve explicit partition of FE_OS and FE_IW based on accurate regional-modification of OS and IW. The FE_IW are served for ionic gating, and the chosen FE_OS (hydrophobic or charged) are served for blocking interference molecules into the nanochannels, decreasing the false signals for the ionic gating in complex environments. Furthermore, we define a composite factor, areas of a radar map, to evaluate the FE_OS performance for blocking interference molecules.