TY - JOUR

T1 - Intracellular Oxygen Sensors Based on Block Copolymer Micelles Loaded With Phosphorescent Ir(III) and Pt(II) Complexes

AU - Елистратова, Анастасия Алексеевна

AU - Жарская, Нина Александровна

AU - Кузнецов, Кирилл Максимович

AU - Соломатина, Анастасия Игоревна

AU - Шакирова, Юлия Равилевна

AU - Критченков, Илья Сергеевич

AU - Туник, Сергей Павлович

AU - Челушкин, Павел Сергеевич

PY - 2026/2/1

Y1 - 2026/2/1

N2 - Polymer micelles are established nanocarriers for hydrophobic molecules, but their use as hosts for sensors of physiological parameters remains underexplored. This work investigates the incorporation of phosphorescent transition metal complexes into block copolymer micelles and examines how composition and structure affect micellar stability and photophysical properties. The study also evaluates their potential as a novel class of oxygen nanosensors with lifetime-based response. Micelles are prepared from block copolymers of poly(ethylene glycol) (PEG) with diverse hydrophobic blocks: polystyrene (PS35-b-PEG115), poly(methyl methacrylate) (PMMA55-b-PEG95), polybutadiene (PBd90-b-PEG115), polydimethylsiloxane (PDMS15-b-PEG115), and polycaprolactone (PCL45-b-PEG115). Six phosphorescent complexes, including three Pt(II) and three Ir(III) species, serve as payloads. Screening of “complex@block copolymer” pairs based on sedimentation stability, phosphorescence decay, and oxygen sensitivity identifies Ir3@PCL45-b-PEG115 loaded with 2 wt.% of Ir3 as the optimal biosensing system. For this system, loading efficiency, size distribution, cross-sensitivity to environmental parameters, Stern–Volmer plots, and MTT cytotoxicity are assessed. Confocal microscopy and phosphorescence lifetime imaging microscopy (PLIM) demonstrate efficient internalization into CHO-K1 and HeLa cells. The sensor shows distinct lifetime responses under hypoxic, normoxic, and intermediate oxygenation, enabling quantitative intracellular oxygen sensing with pO2 resolution of 35–40 mm Hg in both cell monolayers and suspensions.

AB - Polymer micelles are established nanocarriers for hydrophobic molecules, but their use as hosts for sensors of physiological parameters remains underexplored. This work investigates the incorporation of phosphorescent transition metal complexes into block copolymer micelles and examines how composition and structure affect micellar stability and photophysical properties. The study also evaluates their potential as a novel class of oxygen nanosensors with lifetime-based response. Micelles are prepared from block copolymers of poly(ethylene glycol) (PEG) with diverse hydrophobic blocks: polystyrene (PS35-b-PEG115), poly(methyl methacrylate) (PMMA55-b-PEG95), polybutadiene (PBd90-b-PEG115), polydimethylsiloxane (PDMS15-b-PEG115), and polycaprolactone (PCL45-b-PEG115). Six phosphorescent complexes, including three Pt(II) and three Ir(III) species, serve as payloads. Screening of “complex@block copolymer” pairs based on sedimentation stability, phosphorescence decay, and oxygen sensitivity identifies Ir3@PCL45-b-PEG115 loaded with 2 wt.% of Ir3 as the optimal biosensing system. For this system, loading efficiency, size distribution, cross-sensitivity to environmental parameters, Stern–Volmer plots, and MTT cytotoxicity are assessed. Confocal microscopy and phosphorescence lifetime imaging microscopy (PLIM) demonstrate efficient internalization into CHO-K1 and HeLa cells. The sensor shows distinct lifetime responses under hypoxic, normoxic, and intermediate oxygenation, enabling quantitative intracellular oxygen sensing with pO2 resolution of 35–40 mm Hg in both cell monolayers and suspensions.

KW - PLIM

KW - bioimaging

KW - oxygen sensing

KW - phosphorescence

KW - polymer micelles

UR - https://www.mendeley.com/catalogue/3d0d5e0c-8cd4-3262-bb2e-c69e6c2db035/

U2 - 10.1002/pol.20250859

DO - 10.1002/pol.20250859

M3 - Article

VL - 64

SP - 666

EP - 681

JO - Journal of Polymer Science

JF - Journal of Polymer Science

SN - 2642-4150

IS - 3

ER -