Modified polymer nanospheres – characterization and their anti-amyloid activity to insulin amyloid aggregation

Abstract Polylactic acid-based nanoparticles are promising materials due to their tunable properties that are connected to surface modification. We have prepared polylactic acid nanospheres (PLA) with a non-magnetic phase (PLA loaded with various bovine serum albumin (BSA) concentrations) and magnetic phase (PLA loaded with magnetite nanoparticles coated with different amount of BSA (MFBSA)). The morphology, physico-chemical, magnetic and anti-amyloid properties were characterized by several biophysical methods. The amount of BSA used for PLA nanospheres or MFBSA modification played an important role in controlling the hydrodynamic size and zeta potential. In addition, magnetite loaded PLA nanospheres and MFBSA were all superparamagnetic. The potential of modified PLA nanospheres compared to MFBSA and 'naked' PLA to inhibit insulin amyloid fibrillation and destroy mature insulin fibrils was studied in vitro for samples with BSA/Fe3O4 weight ratio of 0.5. Destroying potential of samples was size–dependent, with the smallest MFBSA0.5 having the most significant effect. The strongest inhibitory effect on insulin fibrillation showed PLA-MFBSA0.5, slightly smaller than BSA modified PLA nanospheres.