Fluorescence imaging enabled poly(lactide-co-glycolide)

Abstract

Fluorescent biomaterials have attracted significant research efforts in the past decades. Herein, we report a new series of biodegradable, fluorescence imaging-enabled copolymers, biodegradable photoluminescent poly(lactide-co-glycolide) (BPLP-co-PLGA). Photoluminescence characterization shows that BPLP-co-PLGA solutions, films and nanoparticles all exhibit strong, tunable and stable photoluminescence. By adjusting the molar ratios of L-lactide (LA)/glycolide (GA) and (LA+GA)/BPLP, full degradation of BPLP-co-PLGA can be achieved in 8-16 weeks. The fluorescence decay behavior of BPLP-co-PLGA can be used for non-invasive monitoring of material degradation. In vitro cytotoxicity and in vivo foreign body response evaluations demonstrate that BPLP-co-PLGA exhibits similar biocompatibility to poly(lactide-co-glycolide) (PLGA). The imaging-enabled BPLP-co-PLGA was fabricated into porous scaffolds whose degradation can be monitored through non-invasive imaging and nanoparticles that show theranostic potential demonstrated by fluorescent cellular labeling, imaging and sustained 5-fluorouracil delivery. The development of inherently fluorescent PLGA copolymers is expected to impact the use of already widely accepted PLGA polymers for applications where fluorescent properties are highly desired but limited by the conventional use of cytotoxic quantum dots and photobleaching organic dyes.

Statement of significance: This manuscript describes a novel strategy of conferring intrinsic photoluminescence to the widely used biodegradable polymers, poly(lactide-co-glycolide) without introducing any cytotoxic quantum dots or photo-bleaching organic dyes, which may greatly expand the applications of these polymers in where fluorescent properties are highly desired. Given the already significant impact generated by the use of PLGA and alike, this work contributes to fluorescence chemistry and new functional biomaterial design and will potentially generate significant impact on many fields of applications such as tissue engineering, molecular imaging and labeling, and drug delivery.

Keywords: Biodegradable; Bioimaging; Drug delivery; PLGA; Photoluminescence; Tissue engineering.