Controlled Dye Aggregation in Sodium Dodecylsulfate-Stabilized Poly(methylmethacrylate) Nanoparticles as Fluorescent Imaging Probes

Abstract

Polymer nanoparticles are used extensively in biomedical applications. Poly(methylmethacrylate) (PMMA) nanoparticles obtained via nanoprecipitation were unstable and flocculate or precipitate from solution within a few hours. A simple method to improve the stability of the particles using surfactants at low concentrations was carried out to produce PMMA nanoparticles with long-term stability in water (>6 months). The increased stability was attributed to the incorporation of surfactants inside the polymer particles during nanoprecipitation. The same methodology was also adopted to encapsulate a highly fluorescent hydrophobic perylene tetraester inside the polymer nanoparticles with good stability in water. Because of the presence of the anionic sodium dodecyl sulfate, the particles showed a negative zeta potential of −34.7 mV and an average size of 150 nm. Similarly, the dye-encapsulated polymer nanoparticles showed a zeta potential of −35.1 mV and an average particle size of 180 nm. By varying the concentration of encapsulated dyes inside the polymer nanoparticles, dye aggregation could be controlled, and the fluorescence profiles of the nanoparticles were altered. To understand the uptake and toxicity of the polymer nanoparticles, baby hamster kidney cells were chosen as a model system. The polymer nanoparticles were taken up by the cells within 3 h and were nontoxic at concentrations as high as 100 ppm. The confocal micrographs of the cells revealed localized fluorescence from the polymer nanoparticles around the nucleus in the cytoplasm without the penetration of the nuclear envelope.

Understanding the interactions of poly(methyl methacrylate) and poly(vinyl chloride) nanoparticles with BHK-21 cell line

“…The absorption maxima of the NPs were at 445 nm and 470 nm, and emission maximum was at 550 nm, respectively, which is identical to the solution spectrum of the dye 29 . From the absorbance and emission spectra, spectral inversion or bathochromic shift characteristic of dye aggregation in the NPs was not observed 28 , indicating homogenous distribution of dye inside the polymer NPs. The order of mixing of organic polymer solution with water has an impact on the NP size distribution.…”

“…For the current investigation, we are interested in exploring the uptake and translocation of NPs of two most common polymers, PVC and PMMA and investigated the induced cellular biochemical changes using baby hamster kidney cells (BHK—21) as a model. For easy tracking purpose, fluorescent perylene dye incorporated NPs were prepared from these two polymers using the nanoprecipitation method 28 and fully characterized. Both mechanisms of intake of the luminescent polymer NPs and biochemical changes occurring inside the cells are discussed in detail.…”

Modular Synthesis and Structure–Property Correlation of Pyrene – Rylene Dyes for Cellular Imaging

“…Nanoprecipitation is a kinetically controlled process where parameters such as concentration, temperature, addition rate and presence of stabilizer influence the formation of stable particle . Sodium dodecyl sulfate (SDS, 10 mg), and the appropriate pyrene compound (10 mg) were dissolved in tetrahydrofuran (50 mL).…”

“…Solar cell acceptors based on perylene bisimide coupled with pyrene demonstrated promising power conversion efficiency, which was due to the broad absorption and π‐electron delocalization leading to effective charge transport , . Also, the previous findings from our group demonstrated that perylene tetraester (PTE) based dyes are non‐toxic towards mammalian cells and could be used in bioimaging applications due to their intense fluorescence emission and high photochemical stability …”

Dye‐Loaded Nanoemulsions: Biomimetic Fluorescent Nanocarriers for Bioimaging and Nanomedicine

“…The simplest approach uses optical spectroscopy, where the dye aggregation or leakage can lead to changes in the absorption and emission wavelengths. [151][152][153][154] One of the most powerful methods to study particle integrity is Forster resonance energy transfer (FRET). Since short donor-acceptor distances are required for the efficient FRET (2-10 nm), one should achieve mm concentrations of dyes to realize FRET inside the nanodroplets.…”