Fluorescent Amphiphilic PEG‐Peptide‐PEG Triblock Conjugate Micelles for Cell Imaging

Abstract

A fluorescent amphiphilic poly(ethylene glycol)-peptide-fluorophore-peptide-poly(ethylene glycol) (PEG-Pep-F-Pep-PEG) triblock conjugate with a hydrophobic fluorophore moiety at the centre of the chain is synthesized by "grafting to" technique based on Schiff-base coupling chemistry. The conjugate is characterized by nuclear magnetic resonance (NMR), circular dichroism (CD), and fluorescence spectroscopy techniques. The aqueous solution of the triblock conjugate emits blue light and exhibits a fluorescence emission band at 430 nm. The amphiphilic conjugate molecules undergo self-assembly into micelles (D ≈ 15-20 nm) in aqueous solution as confirmed from transmission electron microscopy (TEM) and dynamic light scattering (DLS). The critical aggregation concentration is determined by pyrene fluorescence assay and is found to be 0.051 mg mL(-1) . The highly stable and low toxic fluorescent PEG-Pep-F-Pep-PEG conjugate micelles are used for imaging of HeLa cells.

Peptide‐poly(tert‐butyl methacrylate) conjugate into composite micelles in organic solvents versus peptide‐poly(methacrylic acid) conjugate into spherical and worm‐like micelles in water: Synthesis and self‐assembly

“…Fluorescence excitation spectra were recorded in a FluoroMax‐3 spectrophotometer of Horiba Jobin Yvon for the determination of critical aggregation concentration (CAC) of a representative sample, Peptide‐PMA‐I conjugate (see Table ) in aqueous solution following an earlier reported method . A series of aqueous solution of Peptide‐PMA‐I conjugate with concentrations ranging from 2 × 10 −4 to 1 mg/mL were first prepared from a stock solution containing 6 × 10 −7 M of pyrene in each vial.…”

“…Thus, in this work, we illustrate the synthesis of another kind of peptide–polymer conjugate comprising of a peptide of different sequences than the reported one, covalently attached with poly( tert ‐butyl methacrylate) (P t BMA) chain end by ATRP using as‐synthesized peptide‐initiator. The attachment of peptide segment with the growing polymer chain is confirmed from 1 H NMR, CD, and MALDI‐TOF MS analyses.…”

Concentration‐mediated multicolor fluorescence polymer carbon dots

“…The outer PEG shell provides dispersion stability toward polar solvents, such as water, methanol and acetone (Fig. S2), and we estimate that the inner PPG‐rich core might be critical for the fluorescence emission of P‐PDs . Aggregate formation in P‐PDs at high concentrations was investigated by monitoring the particle size distribution using DLS analysis (Fig.…”

Hierarchical nanostructures of tunable shapes through self-aggregation of POSS end-functional polymer and poly(ionic liquid) hybrids

“…The higher size of the nanospheres as measured from DLS than that measured from FESEM can be ascribed to the presence of highly solvated PVim layer. In general the size of the block copolymer micelle is usually much lower than 50 nm [42]. Thus, we may assume that the observed nanospheres are not the primary unit micelles of POSSPVim1 hybrid.…”

“…It is thus expected that the POSS-PVim in aqueous solution (pH 6) can form primary hybrid micelles, where, the PVim segment would constitute the outer layer and POSS crystalline aggregates at the core. We then investigated the micellization behavior and measured the critical aggregation concentration (CAC) of the formed hybrid micelles from POSS-PVim1 in water using pyrene as the fluorescent probe [42]. Pyrene exhibits two intense emission peaks at 375 nm (I 375 ) and 392 nm (I 392 ) in water, where I 392 is very much sensitive to the polarity of the environment.…”