Perylene-Tagged Polycaprolactone Block Copolymers and Their Enzyme-Biodegradable Fluorescent Nanoassemblies for Intracellular Bio-imaging in Cancer Cells

Abstract

The present investigation reports enzyme-biodegradable perylenebisimide (PBI)-tagged polycaprolactone (PCL) block copolymers, and their aqueous nanoassemblies were employed as probes for intracellular bio-imaging in cancer cells. Bishydroxyl functionalized PBI initiator was tailor-made, and it was employed as initiator for the ring opening polymerization (ROP) methodology to make PBI-tagged tert-butyl ester-substituted polycaprolactone (PBI-BPCL x ) block copolymers. The deprotection of these copolymers yielded carboxylic acid-substituted PBI-CPCL x amphiphilic block copolymers. The carboxylic blocks were self-assembled to produce stable red-fluorescent nanoparticles of <150 nm in size in aqueous medium with fluorescent quantum yield of ϕ = 0.25–0.30 suitable for bio-imaging application. In vitro studies confirmed that the aliphatic polyester backbone in the PBI-CPCL x polymer nanoparticles was readily biodegradable by lysosomal enzymes under physiological conditions. Dynamic light scattering, gel permeation chromatography, photophysical studies, and MALDI-TOF-MS analysis provided evidence of the enzymatic biodegradation. Cytotoxicity studies revealed that the PBI-CPCL x nanoparticles were highly biocompatible toward both cervical cancer and breast cancer cell lines up to a concentration of 100 μg/mL. Confocal microscopy analysis confirmed the uptake and accumulation of red-fluorescent PBI-CPCL x polymer nanoparticles in the perinuclear environment of the cells. The present approach puts forward a PBI-PCL block copolymer design as enzyme-responsive red-fluorescent nanoprobes for bio-imaging in cancer and normal cells.

Fluorescent ABC‐Triblock Polymer Nanocarrier for Cisplatin Delivery to Cancer Cells

“…The emission spectrum recorded at an absorption maximum of 495 nm exhibited a maximum at 540 nm showing characteristic emission of PBI chromophore. The fluorescence quantum yield (QY) of the ABC triblock copolymer and the ABC triblock Pt-prodrug were determined in THF and water, respectively using N,N'bis(hexylheptyl)perylene-3,4,9,10-bis(dicarbiximide) [31] as standard in chloroform. The QY of the ABC triblock copolymer in THF and water was measured to be 0.90 and 0.31, respectively and that of ABC triblock Pt-prodrug in water was measured to be 0.25.…”

“…The t-butyl ester substituted caprolactone (monomer 1) and hydroxyl functionalized fluorescent PBI initiator were synthesized following the reported procedure. [31] The PEG substituted ɛ-caprolactone monomer (monomer 2) was synthesized following the steps as shown in Scheme 1. 1,4-Cyclohexanediol was reacted with t-butyl acrylate by Michael addition reaction to produce monosubstituted alcohol which was subsequently oxidized into ketone with PCC (compound 1).…”

“…Among the known π-Conjugated polymers, polymers based on perylene bisimide (PBI) are widely employed imaging tools for biomedical applications owing to its high quantum yield. [30,31] Further, literature reports on perylene-based polymers and supramolecular assemblies have exhibited the biocompatibility of PBI for in vitro as well as in vivo applications. [32] With very few exceptions, most of the above-mentioned cisplatin delivery nanocarriers were predominately built on the non-biodegradable polymer or scaffold platform; as a consequence, the fate of the polymer nanocarriers after Pt-drug delivery, their degradation pathways and clearance under physiological conditions are not very clearly established for their long-term impact in the biomedical field.…”

Preparation of poly (ε‐caprolactone) as a gel electrolyte fordye‐sensitizedsolar cells

“…Poly (ε-caprolactone) (PCL) is a hydrophobic biopolymer, which shows good biodegradability, biocompatibility, environmentally friendly, and drug permeability. [36][37][38] PCL acts as a wide range of catalysts toward ring-opening polymerization (ROP) of ε-caprolactone (CL) that has the flexibility to ease in synthetic polymers at low cost. 39,40 Synthetic polymers have excellent solubility in common organic solvents and, mostly combined with copolymers result in good crystallization behaviors, and the morphology is achieved to increase the flexibility of the resulting biomaterial.…”

Near infrared absorption/emission perylenebisimide fluorophores with geometry relaxation-induced large Stokes shift

“…Recently, perylenebisimide (PBI) and its derivatives have been widely applied to the areas of uorescence probe and intracellular uorescence imaging image, [1][2][3][4][5] organic photovoltaic devices, [6][7][8][9][10][11][12] charge transporting materials, [13][14][15][16][17][18] luminescent materials [19][20][21][22][23][24] and triplet photosensitizers [25][26][27][28][29][30][31][32] due to its excellent luminous performance, photo-stability and electronic transmission capacity. Traditional PBI dyes always show the strong absorption in visible region and with small Stokes shi (generally less than 60 nm).…”