title: Thermosensitive nanospheres with a gold layer revealed as low-cytotoxic drug vehicles.
abstract: In this paper, the positive effect of a gold layer on cell viability is demonstrated by examining the results given by 3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4-sulfop henyl)-2H-tetrazolium (MTS) assay and two-color cell fluorescence viability (TCCV) assay. These cytotoxicity tests were performed with human cervical adenocarcinoma cells (HeLa cell line) and transformed African green monkey kidney fibroblast cells (Cos-7 cell line). To fabricate the nanostructures as drug vehicles, first, poly(l,l-lactide-co-ethylene glycol) (PLLA-PEG) and poly(N-isopropylacrylamide-co-D,D-lactide) (PNIPAAm-PDLA) were synthesized, and then two kinds of thermosensitive nanospheres comprising "shell-in-shell" structures without a gold layer (PLLA-PEG@PNIPAAm-PDLA) and with a gold layer (Au@PLLA-PEG@PNIPAAm-PDLA) were constructed by a modified double-emulsion method (MDEM). Both of them displayed a unique thermosensitive character exhibiting the lower critical solubility temperature (LCST) at 36.7 degrees C which was confirmed by UV-vis spectroscopy and differential scanning calorimetry (DSC). The release profiles of entrapped bovine serum albumin (BSA) were monitored at 22 and 37 degrees C, respectively, to reveal the thermal dependence on the release rate. In cell viability tests, both PLLA-PEG@PNIPAAm-PDLA and Au@PLLA-PEG@PNIPAAm-PDLA showed excellent cell viability, and furthermore, Au@PLLA-PEG@PNIPAAm-PDLA, particularly at high doses, exhibited more enhanced cell viability than PLLA-PEG@PNIPAAm-PDLA. This effect is mainly attributed to the gold layer which binds the protein molecules first and consequently facilitates transmembrane uptake of essential nutrients in the cell media, resulting in favorable cell proliferation.
authors.affiliation: Materials Chemistry Division, Royal Institute of Technology, Stockholm SE-100 44, Sweden.
authors.forename: Jian
authors.initials: J
authors.lastname: Qin
authors.forename: Yun Suk
authors.initials: YS
authors.lastname: Jo
authors.forename: Jong Eun
authors.initials: JE
authors.lastname: Ihm
authors.forename: Do Kyung
authors.initials: DK
authors.lastname: Kim
authors.forename: Mamoun
authors.initials: M
authors.lastname: Muhammed
mesh_terms: D000178:Acrylamides / Q000737:chemistry*; D000818:Animals; D000970:Antineoplastic Agents / Q000008:administration & dosage; D001692:Biological Transport / Q000187:drug effects; D019556:COS Cells / Q000187:drug effects; D002152:Calorimetry, Differential Scanning; D002470:Cell Survival / Q000187:drug effects; D002522:Chlorocebus aethiops; D004337:Drug Carriers / Q000737:chemistry*; D005260:Female; D006046:Gold / Q000737:chemistry*; D006367:HeLa Cells / Q000187:drug effects; D006801:Humans; D007773:Lactates / Q000737:chemistry*; D008297:Male; D011092:Polyethylene Glycols / Q000737:chemistry*; D012710:Serum Albumin, Bovine / Q000737:chemistry; D012995:Solubility; D013056:Spectrophotometry, Ultraviolet; D013696:Temperature; D013997:Time Factors; D002583:Uterine Cervical Neoplasms / Q000473:pathology
chemical_list: D000178:Acrylamides; D000970:Antineoplastic Agents; D004337:Drug Carriers; D007773:Lactates; C116493:poly(N-isopropylacrylamide-b-lactide); C088513:poly(lactic acid-ethylene glycol); D012710:Serum Albumin, Bovine; D011092:Polyethylene Glycols; D006046:Gold