Influence of Carboxyl Group Ratios on the Design of Breast Cancer Targeting Bimodal MR/NIR-II Imaging Probe from PLGA@Gd-DOTA@PEG Micelles Conjugating Herceptin

We developed a small MRI/NIR-II probeto target HER2(tetanucleotide)breast cancer cells. The probe is composed of PLGA-b-PEG micelles encapsulated NIR-II, and Gd-DOTA is conjugated at theborder of PLGA/PEG. Herceptin was then conjugated to carboxyl residuesof PLGA-b-PEG chains. We examined the influence ofcarboxyl group ratios on the probe property stability and Herceptinconcentration and the binding affinity to HER2(+) cells correspondingto the -COOH ratios. The binding assays demonstrated that theoptimal surface ratio of -COOH is 5%, which is less affectedby fluorescence reduction and which exhibited the highest antigen-capturingactivity.

Automated summary

We developed a small MRI/NIR-II probe for HER2 breast cancer cells. The probe contains PLGA-b-PEG micelles encapsulated with NIR-II and Gd-DOTA conjugated at the border of PLGA/PEG. Herceptin is then conjugated to carboxyl residues of PLGA-b-PEG chains. Through binding assays, we found that the optimal surface ratio of -COOH is 5% for stable probe properties and high antigen-capturing activity.