“…For a deeper comprehension of the biological implications of pH gradients, sensitive and focused pH monitoring devices for living cells are consequently crucial. Because of this, many strategies have appeared in which CDs are used to detect pH, including label-free CDs [ [469] , [470] , [471] , [472] , [473] ], nitrogen-doped CDs [ [474] , [475] , [476] , [477] , [478] , [479] , [480] ], amine-coated CDs [ [481] , [482] , [483] , [484] , [485] , [486] , [487] , [488] ], mesoporous silica-CDs [ [489] , [490] , [491] , [492] , [493] , [494] , [495] ], and CDs with other materials [ [496] , [497] , [498] , [499] , [500] , [501] , [502] , [503] , [504] , [505] ].…”