a. Schematic of TBI-ABN, which releases a cleaved peptide (c-Peptide) biomarker after cleavage of the peptide substrate by calpain-1. b. In vitro cleavage kinetics of free peptide (left) and peptide and VT750 conjugated to PEG to form TBI-ABN (right), incubated with human calpain-1 (n = 3 technical replicates, mean ± SD). c. Michaelis-Menten curves derived from the maximal velocities of cleavage (n = 3 technical replicates, mean ± SD). d. Dynamic range of free peptide and TBI-ABN on a sandwich ELISA, with α-FAM as the capture antibody and streptavidin-HRP as the detection molecule. (n = 3 technical replicates, mean ± SD, dashed line denotes the limit of detection (LOD)).