Quantum dot–peptide conjugates as energy transfer probes for sensing the proteolytic activity of matrix metalloproteinase-14

Z Jin, N Dridi, G Palui, V Palomo, JV Jokerst… - Analytical …, 2023 - ACS Publications
Analytical Chemistry, 2023ACS Publications
We detail the assembly and characterization of quantum dot (QD)− dye conjugates
constructed using a peptide bridge specifically designed to recognize and interact with a
breast cancer biomarker─ matrix metalloproteinase-14 (MMP-14). The assembled QD
conjugates are then used as optically addressable probes, relying on Förster resonance
energy transfer (FRET) interactions as a transduction mechanism to detect the activity of
MMP-14 in solution phase. The QDs were first coated with dithiolane poly (ethylene …
We detail the assembly and characterization of quantum dot (QD)−dye conjugates constructed using a peptide bridge specifically designed to recognize and interact with a breast cancer biomarker─matrix metalloproteinase-14 (MMP-14). The assembled QD conjugates are then used as optically addressable probes, relying on Förster resonance energy transfer (FRET) interactions as a transduction mechanism to detect the activity of MMP-14 in solution phase. The QDs were first coated with dithiolane poly(ethylene glycol) (PEG) bearing a carboxyl group that allows coupling via amide bond formation with different dye-labeled peptides. The analytical capability of the conjugates is enabled by correlating changes in the FRET efficiency with the conjugate valence and/or QD-to-dye separation distance, triggered and modulated by enzymatic proteolysis of surface-tethered peptides. The FRET probe exhibits great sensitivity to enzyme digestion with sub-nanomolar limit of detection. We further analyze the proteolysis data within the framework of the Michaelis–Menten model, which considers the fact that surface-attached peptides have a slower diffusion coefficient than free peptides. This results in reduced collision frequency and lower catalytic efficiency, kcat/KM. Our results suggest that our conjugate design is promising, effective, and potentially useful for in vivo analysis.
ACS Publications
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