Cell up-take control of gold nanoparticles functionalized with a thermoresponsive polymer

Abstract

Surface decoration of gold nanoparticles with thermoresponsive polymers endows a temperature tunable colloidal system switchable for enhanced intracellular up-take. Gold nanoparticles (AuNP, 18 ± 11 nm-diameter) produced by laser ablation synthesis in liquid solution were surface coated with thermoresponsive thiol terminated poly-N-isopropylacrylamide-co-acrylamide co-polymer possessing a lower critical solution temperature (LCST) at 37 °C. Under selected conditions about 3800 polymer chains were conjugated per particle. The polymer coated nanoparticles were found to display thermosensitive properties, as in solution they exhibited reversible aggregation/deaggregation above and below the LCST, respectively. Cell culture studies showed that the polymer decorated AuNP were located into human breast adenocarcinoma MCF7 cells treated at 40 °C (12000 AuNP/cell) with more than 80-fold greater up-take compared to cells treated at 34 °C with the same particles (140 AuN/cell). This difference is attributable to a ‘switching’ of the polymer coating to a globule state at 37 °C and an increased hydrophobicity of the particles with a simultaneous loss of the ‘stealth’ properties of the polymer coating. By contrast, cell up-take of uncoated AuNP (about 6000 AuNP/cell) did not depend on the incubation temperature. These data show that good control of the AuNP cell up-take can be obtained with the new polymer-gold nanoconjugates, and suggest that these systems might find use for targeting cells in vitro by a small temperature change or in vivo in body sites, such as inflamed or tumour tissues, where a temperature variation is already present

On Biodecorated Gold Nanoparticles Distributed within Tissues and Cells

“…The interaction of unstable nanoparticles with biomolecules probably leads to the particle agglomeration and their concentration in the liver. Similar nonfunctionalized 18-nm AuNPs and the particles coated also with polyacrylamide displayed no cytotoxicity to human breast adenocarcinoma cells [11]. No cytotoxic effect was also reported for smaller 10-nm unmodified AuNPs towards dendritic cells by Villiers et al [12].…”

Sex selection of sperm in farm animals: status report and developmental prospects

“…Such effects can be nicely exemplified when comparing, for instance, the influence of ligands on internalisation. While primary ligand-free AuNPs entered the cells by an unknown non-endosomal uptake mechanism (Salmaso et al 2009, AuNPs with ordered arrangements of hydrophilic and hydrophobic functional groups were internalised by membrane wrapping (Verma et al 2008), and AuNP with citrate ligands underwent endocytosis (Shukla et al 2000).…”

Immobilization of biomolecules on the surface of inorganic nanoparticles for biomedical applications

“…This aggregation strongly increased the scattering of light, with a color different from that scattered from the original Apt-AuNPs and cell organelles. Salmaso et al [31] reported on AuNPs that were surface-coated with thermoresponsive thiol-terminated poly-N-isopropylacrylamide-co-acrylamide copolymer. The cell uptake of polymer-coated AuNPs can be temperature-controlled; this opens new perspectives for in vivo testing aimed at thermally controlled targeting of tumors or inflamed tissues.…”

“…Here, we review a few immobilization processes and show the reaction paths for a better understanding of biomolecule immobilization systems. [31] 3.1.1 Synthesis of PNIPAm-co-Am-SH. PNIPAm-co-Am-COOH (97.3 mg, 16.2 µmol) was dissolved in 0.75 ml of anhydrous DMSO and N-hydroxysuccinimide (HOSu) (19.7 mg, 171 µmol) and dicyclohexylcarbodiimide (DCC) (29 mg, 140.7 µmol) were added (figure 1).…”