title: Gold nanostars coated with neutral and charged polyethylene glycols: A comparative study of in-vitro biocompatibility and of their interaction with SH-SY5Y neuroblastoma cells.
abstract: Gold nanostars (GNS) have been coated with four different polyethylene glycols (PEGs) equipped with a -SH function for grafting on the gold surface. These PEGs have different chain lengths with average MW=2000, 3000, 5000 and average number of -O-CH2-CH2 - units 44, 66, and 111, respectively. Two are neutral and two are terminated with -COOH and -NH2 functions, thus bearing negative and positive charges at physiological pH, thanks to the formation of carboxylate and ammonium groups. The negative charge of the GNS coated with PEG carboxylate has also been exploited to further coat the GNS with the PAH (polyallylamine hydrochloride) cationic polymer. Vitality tests have been carried out on SH-SY5Y cells treated with the five differently coated GNS for 4, 24, and 48 h, at Au concentrations ranging from 1.25 to 100 μg/mL. The same tests have been repeated with the pure PEGs and PAH. Excellent biocompatibility was found for all PEGs, independently on charge and chain length, both for coated GNS and for the pure polymers. On the contrary, poor biocompatibility was found for PAH overcoated GNS and for pure PAH, although the latter only at high concentrations. Exploiting the two-photon luminescence of GNS, we have found by confocal laser scanning microscopy that when GNS are coated with PEGs they do not enter SH-SY5Y cells, while when overcoated with PAH they massively penetrate into the cytoplasm. This causes cell death by dramatically changing cell morphology, as demonstrated also by atomic force microscopy.
authors.affiliation: Dipartimento di Chimica, Università di Pavia, Viale Taramelli, 12, 27100 Pavia, Italy. Electronic address: piersandro.pallavicini@unipv.it.
authors.forename: Piersandro
authors.initials: P
authors.lastname: Pallavicini
authors.affiliation: Dipartimento di Chimica, Università di Pavia, Viale Taramelli, 12, 27100 Pavia, Italy.
authors.forename: Elisa
authors.initials: E
authors.lastname: Cabrini
authors.affiliation: Dipartimento di Scienze e Tecnologie Biologiche, Chimiche e Farmaceutiche (STEBICEF), Università di Palermo, Via Archirafi, 32, 90123 Palermo, Italy.
authors.forename: Gennara
authors.initials: G
authors.lastname: Cavallaro
authors.affiliation: Dipartimento di Fisica "G. Occhialini", Università Milano Bicocca, Piazza della Scienza, 3, 20126 Milano, Italy.
authors.forename: Giuseppe
authors.initials: G
authors.lastname: Chirico
authors.affiliation: Dipartimento di Fisica "G. Occhialini", Università Milano Bicocca, Piazza della Scienza, 3, 20126 Milano, Italy.
authors.forename: Maddalena
authors.initials: M
authors.lastname: Collini
authors.affiliation: Dipartimento di Fisica "G. Occhialini", Università Milano Bicocca, Piazza della Scienza, 3, 20126 Milano, Italy.
authors.forename: Laura
authors.initials: L
authors.lastname: D'Alfonso
authors.affiliation: Dipartimento di Chimica, Università di Pavia, Viale Taramelli, 12, 27100 Pavia, Italy.
authors.forename: Giacomo
authors.initials: G
authors.lastname: Dacarro
authors.affiliation: Dipartimento di Chimica, Università di Pavia, Viale Taramelli, 12, 27100 Pavia, Italy.
authors.forename: Alice
authors.initials: A
authors.lastname: Donà
authors.affiliation: Dipartmento di Scienze del Farmaco, Università di Pavia, Viale Taramelli, 12, 27100 Pavia, Italy.
authors.forename: Nicoletta
authors.initials: N
authors.lastname: Marchesi
authors.affiliation: Dipartimento di Chimica, Università di Pavia, Viale Taramelli, 12, 27100 Pavia, Italy.
authors.forename: Chiara
authors.initials: C
authors.lastname: Milanese
authors.affiliation: Dipartmento di Scienze del Farmaco, Università di Pavia, Viale Taramelli, 12, 27100 Pavia, Italy.
authors.forename: Alessia
authors.initials: A
authors.lastname: Pascale
authors.affiliation: Dipartimento di Fisica "G. Occhialini", Università Milano Bicocca, Piazza della Scienza, 3, 20126 Milano, Italy.
authors.forename: Laura
authors.initials: L
authors.lastname: Sironi
authors.affiliation: Dipartimento di Chimica, Università di Pavia, Viale Taramelli, 12, 27100 Pavia, Italy.
authors.forename: Angelo
authors.initials: A
authors.lastname: Taglietti
mesh_terms: D045744:Cell Line, Tumor; D002470:Cell Survival / Q000187:drug effects; D006046:Gold / Q000737:chemistry*; D006801:Humans; D053768:Metal Nanoparticles / Q000737:chemistry; D046529:Microscopy, Electron, Transmission; D015394:Molecular Structure; D009447:Neuroblastoma / Q000188:drug therapy; D011092:Polyethylene Glycols / Q000737:chemistry / Q000494:pharmacology* / Q000627:therapeutic use
chemical_list: D011092:Polyethylene Glycols; D006046:Gold
keywords: Biocompatibility; Endocytosis; Gold nanostars; Nanomedicine; Polyethylene glycol; Two-photon luminescence