Luminescent Difluoroboron β-Diketonate PLA–PEG Nanoparticle

Abstract

Luminescent difluoroboron β-diketonate poly(lactic acid) (BFbdkPLA) materials serve as biological imaging agents. In this study, dye structures were modified to achieve emission colors that span the visible region with potential for multiplexing applications. Four dyes with varying π-conjugation (phenyl, naphthyl) and donor groups (-OMe, -NMe) were coupled to PLLA-PEG block copolymers (∼11 kDa) by a postpolymerization Mitsunobu reaction. The resulting dye-polymer conjugates were fabricated as nanoparticles (∼55 nm diameter) to produce nanomaterials with a range of emission colors (420-640 nm). For increased stability, dye-PLLA-PEG conjugates were also blended with dye-free PDLA-PEG to form stereocomplex nanoparticles of smaller size (∼45 nm diameter). The decreased dye loading in the stereoblocks blue-shifted the emission, generating a broader range of fluorescence colors (410-620 nm). Tumor accumulation was confirmed in a murine model through biodistribution studies with a red emitting dimethyl amino-substituted dye-polymer analogue. The synthesis, optical properties, oxygen-sensing capabilities, and stability of these block copolymer nanoparticles are presented.

A Perspective on Polylactic Acid-Based Polymers Use for Nanoparticles Synthesis and Applications

“…Kerr et al (2017) synthesized dye-PLLA-conjugates using Difluoroboron β-Diketonates as dyes, which were subsequently employed to obtain nanoparticles (average diameter 55 nm) for imaging purposes. In order to improve stability, the authors added PDLA-PEG to promote stereocomplexation.…”

Meta‐Dimethoxy‐Substituted Difluoroboron Dibenzoylmethane Poly(Lactic Acid) Nanoparticles for Luminescence Anisotropy

“…Nanoparticles were prepared as previously described . From less polar to highly polar, 1,4‐dioxane, THF, acetone, dimethylformamide (DMF), and acetonitrile solvents were chosen to dissolve the polymer, then were precipitated into water while stirring to form nano‐droplets.…”

Methoxy‐Substituted Difluoroboron Benzoylacetonate Complexes with Color‐Tunable Phosphorescence

“…Bright fluorescence (F), accessible room‐temperature phosphorescence (RTP),, and thermally‐activated delayed fluorescence (TADF) are all desirable features for fluorophores as bioprobes, sensors and devices. Difluoroboron β‐diketonate (BF 2 bdk) dyes are a rare example that shows all of these properties that are controllable through molecular design . Furthermore, a single BF 2 bdk dye can be used for many applications.…”