Incorporating functionalized polyethylene glycol lipids into reprecipitated conjugated polymernanoparticles for bioconjugation and targeted labeling of cells

Abstract

We report a simple and rapid method to prepare extremely bright, functionalized, stable, and biocompatible conjugated polymer nanoparticles incorporating functionalized polyethylene glycol (PEG) lipids by reprecipitation. These new nanoparticles retain the fundamental spectroscopic properties of conjugated polymer nanoparticles prepared without PEG lipid, but demonstrate greater hydrophilicity and quantum yield compared to unmodified conjugated polymer nanoparticles. The sizes of these hybrid nanoparticles, as determined by TEM, were 21–26 nm. Notably, these nanoparticles were prepared with several PEG lipid functional end groups and the biotin and carboxy moieties can be easily bioconjugated. We have demonstrated the availability of these end groups for functionalization using the interaction of biotin PEG lipid conjugated polymer nanoparticles with streptavidin. Biotinylated PEG lipid conjugated polymer nanoparticles bound streptavidin-linked magnetic beads, while carboxy and methoxy PEG lipid modified nanoparticles did not. Similarly, biotinylated PEG lipid conjugated polymer nanoparticles bound streptavidin-coated glass slides and could be visualized as diffraction-limited spots, while nanoparticles without PEG lipid or with non-biotin PEG lipid end groups were not bound. To demonstrate that nanoparticle functionalization could be used for targeted labeling of specific cellular proteins, biotinylated PEG lipid conjugated polymer nanoparticles were bound to biotinylated anti-CD16/32 antibodies on J774A.1 cell surface receptors, using streptavidin as a linker in a sandwich format. These data demonstrate the utility of these new nanoparticles for fluorescence based imaging and sensing.

Highly Fluorescent Semiconducting Polymer Dots for Biology and Medicine

“…[40–44] There have been significant efforts to create versatile semiconducting polymer nanoparticles (a small subset of which are Pdots), tune their properties and functions, and improve their performance for biomedical studies. The research efforts include exploring new preparation methods, [45,46,69,70,72] investigating nanoparticle formation mechanisms, [120,121] probing nanoparticle photophysics, [47,49,54,122,123] characterizing the fluorescence performance, [48,51,56,58] tuning the emission color, [47,49,71,89] engineering the particle surface, [56–58,64–66,98,102] encapsulating inorganic materials, [96,97,99,104,105] developing nanoparticle sensors, [52,59,60,62,74,77] imaging cellular structures, [56,57,63–66] and in vivo targeting in small animals. [58,72] …”

“…[40–44] For biological applications in particular, nanoparticles composed of semiconducting polymers can exist in many different forms having important functional implications. For example, semiconducting polymer nanoparticles can be prepared from hydrophobic semiconducting polymers, [45–80] polyelectrolytes, or hydrophilic polymers, [81–88] as self-assembled nanoparticles from amphiphilic polymers, [89–93] as hydrophobic semiconducting polymer-loaded poly(D, L-lactide- co -glycolide) (PLGA) particles, [94–97] as phospholipid-encapsulated or PEG-capped hydrophobic polymer nanoparticles, [98–102] and as semiconducting polymer-coated inorganic nanoparticles. [103–105] Among these nanoparticles, the fluorescence, colloidal stability, and functional performance are highly dependent on their particle size, composition, internal structure, and surface properties.…”

Lipid-Based Drug Delivery Systems in Cancer Therapy: What Is Available and What Is Yet to Come

“…Apart from the incorporation of cytotoxic chemotherapeutic agents into LPNs as a single or combinatorial drug transport system with/without active targeting, LPNs have been used for the delivery of genes Zhong et al, 2010), siRNA (Shi et al, 2011;Hasan et al, 2012;Yang et al, 2012a), and diagnostic imaging agents (Kandel et al, 2011;Mieszawska et al, 2012). The development of nanoparticle drug delivery systems, such as lipid-based nanoparticles, and particularly liposomes, has emerged as a promising strategy for the treatment of cancer.…”

The relative brightness of PEG lipid-conjugated polymer nanoparticles as fluid-phase markers in live cells

“…In addition, the nanoparticle surface can be coated with specific external shell materials like polyethylene glycol (PEG) lipid[8–11], amphiphilic block copolymer[9], or silica[12] to increase nanoparticle solubility and stability in aqueous environments and provide functional groups for targeting to cell surface specific receptors and active delivery to specific cellular locations[11, 13, 14]. However, some nanoparticles result in cellular toxicity, which can arise from either core nanoparticle or the external shell composition[15–17].…”