Next, we were interested to study the reversibility and reusability of the covalent cargo reagent for live-cell imaging. We conjugated a magnetic bead to our covalent cargo that was designed to form bonds with the cell membrane such that the bonds are stimulated by pH. The magnetic beads were essential to isolate the cargo reagent, both from excess cargo that was not conjugated to cells at 0.1 mg/mL concentration during initial conjugation (unconjugated magnetic cargo), as well as, after the cell-surface bond disruption and recovery of the cell conjugated cargo reagent by pH stimulation (pH recovered magnetic cargo), as shown in the schematic representation in Figure . Covalent cargo conjugated Jurkat T cells were treated with PBS at pH 5.5 to disrupt surface conjugation, observed after 30 minutes of incubation, as evident from no green fluorescence on the cell surface. Next, the mixture of T cells and pH-stimulated unconjugated magnetic cargo reagents were recovered using magnetic isolation from the supernatant.