Biodegradable nano-probes for the detection of molecular retinal biomarkers of diabetes

Abstract

Purpose : Early detection of diabetic retinopathy before structural injury could allow treatment before irreversible damage occurs. Our laboratory established the first and currently only existing in vivo technology for visualization of specific molecules on the vascular endothelium. This approach identified VEGFR-2 as a candidate biomarker of diabetes in the retina. Here we introduce bio-compatible nano-probes using FDA-approved components for future clinical development.

Methods : To target VEGFR-2, nano-probes (NPs) were generated using poly(lactic-co-glycolic acid) (PLGA), conjugated with polyethylene glycol (PEG). The fluorophore rhodamine 123 was encapsulated in the PLGA-PEG backbone. The nano-probes were functionalized using a peptide with binding affinity to the human VEGFR-2. Nucleic magnetic resonance was used to confirm the chemical composition after each conjugation step. Nano-probe morphology was examined in electron microscopy. The zeta potential of the nano-probe was measured to confirm the net charge.

Results : The characterization of NPs showed a mean diameter of 230±3.1 nm, a mean zeta potential of -38.3±2.17 mV, and an 83% encapsulation efficiency. Peptide conjugation was confirmed in nuclear magnetic resonance (NMR). Adhesion of the NPs to immobilized recombinant human VEGFR-2 protein was studied in video microscopy under dynamic flow conditions.

Conclusions : We introduce the design and pre-clinical characterization of nano-probes from safe and non-toxic components. Our preliminary results show that our targeted NPs provide a quantifiable signal detectable through fundus imaging. This work is a foundation for future clinical diagnosis of subtle molecular abnormalities associated with diabetes complications in the retina.

This abstract was presented at the 2019 ARVO Annual Meeting, held in Vancouver, Canada, April 28 - May 2, 2019.