PLGA-based nanofibers with a biomimetic polynoradrenaline sheath for rapid in vivo sampling of tetrodotoxin and sulfonamides in pufferfish

Abstract

Nanomaterials have shown great potential for application in microextraction due to their distinguishing nanoscale architectures and superior physicochemical properties. Herein, novel poly(lactic-co-glycolic acid) (PLGA) solid-phase microextraction (SPME) fibers, which were incorporated with a self-assembled graphene oxide (GO)-coated γ-Al₂O₃ composite (Al₂O₃@GO), were fabricated on stainless steel wires via an electrospinning method. The as-spun nanofibers were further sheathed through the self-polymerization of noradrenaline (NA), an agonist found in oysters, to provide a compatible biointerface and antifouling capacity. Acting as the coating substrate of the as-prepared fibers, PLGA is known for its prominent biocompatibility and biodegradability, while the adsorptive Al₂O₃@GO particles helped to increase their loading capacity. The modified PLGA-based electrospun nanofibers exhibited much higher extraction efficiency compared with the thicker polydimethylsiloxane (PDMS) coatings (165 μm) and polyacrylate (PA) coatings (85 μm). Due to the fine biointerface of the PLGA-based nanofibers, a rapid extraction equilibrium was observed and sampling with the custom-made Al₂O₃@GO–PLGA@PNA fibers could be accomplished within 15 min. The fibers were then successfully employed for simultaneous in vivo sampling of tetrodotoxin (TTX) and sulfonamides (SAs) in the dorsal–epaxial muscle of living pufferfish (Takifugu obscurus), and satisfactory sensitivities with limits of detection (LODs) in the range of 0.52–2.30 ng g⁻¹ and comparable accuracies to the conventional liquid extraction (LE) method were achieved. In vivo sampling of target pharmaceuticals with the modified nanofibers showed their feasibility for further metabolomics and pharmacokinetics studies in biotissues.