“…Among them, hydrogels have been utilized for the development of wearable glucose sensors ( Elsherif et al., 2018 ; Zhang et al., 2020d ). The mechanisms of hydrogel based glucose sensors are mainly based on electrochemical sensing ( Guascito et al., 2011 ; Ren et al., 2006 ; Su et al., 2013 ; Vaddiraju et al., 2009 ; Wu and Yin, 2013 ; Zhai et al., 2013 ), optical sensing ( Mesch et al., 2015 ; Suri et al., 2003 ; Vilozny et al., 2011 ; Zhang et al., 2013 , 2014 ; Kim et al., 2016b ; Wu et al., 2019b ; Ying et al., 2020b ), sensing based on geometric change ( Cambre and Sumerlin, 2011 ; Hisamitsu et al., 1997 ; Kataoka et al., 1998 ; Kitano et al., 1991a , 1991b ), and electrical sensing ( Kajisa and Sakata, 2017 ; Shang et al., 2016 ). Some mechanisms such as geometric changes have been utilized to design the glucose-responsive wearable insulin patch for regulation of blood glucose ( Lee et al., 2017 ; Wang et al., 2020a ; Yu et al., 2020a ).…”