scientificprotocols authored over 7 years ago
Authors: Nadja C. Bigall & Wolfgang J. Parak
In this protocol, a facile procedure for the transfer of quantum dots or different nanoparticles from organic synthesis into aqueous solution is described. Therefore, in the first step, poly(isobutylene maleic anhydride) is modified with hydrophobic side chains via amide bond formation. In the second step, this polymer is mixed with the nanoparticles and wrapped around them. The idea is let the side chains of the polymer intercalate with the inorganic ligands of the nanoparticles, and that the backbone of the polymer which is multifold charges due to the carboxylic groups leads to excellent water solubility. The nanoparticles are finally soluble in buffer solution and cleaned by gel electrophoresis or size exclusion chromatography. Additional functionalization of these nanoobjects is possible via amide bond formation.
Tetrahydrofurane (anhydrous), chloroform (anhydrous), poly(isobutylene- alt -maleic anhydride) (Mw ~ 6000 g mol-1, Aldrich, which corresponds to about 39 monomer units per polymer), dodecylamine (Sigma), methoxy-PEG-amine (Mw=5000 g mol-1 from Rapp Polymere or Mw=750 g mol-1 from Fluka) biotin-PEG-amine Mw= 5000 g mol-1 from Rapp Polymere or Mw= 720 g mol-1 from Sigma, aminophenyl β-D-galactopyranoside (Sigma) and fluorescein amine (Aldrich), are used without further purification.
Size exclusion chromatography is conducted on an Agilent 1100 HPLC system with a Sephacryl S-300 HR column. Therefore, the mobile phase chosen is 150 mM NaCl in 50 mM sodium borate at pH 9.0
I. Design of the polymer
II. Polymer coating of the nanoparticles
Design of an Amphiphilic Polymer for Nanoparticle Coating and Functionalization. Cheng-An J. Lin, Ralph A. Sperling, Jimmy K. Li, Ting-Ya Yang, Pei-Yun Li, Marco Zanella, Walter H. Chang, and Wolfgang J. Parak. Small 4 (3) 334 - 341 03/03/2008 doi:10.1002/smll.200700654
Nadja C. Bigall & Wolfgang J. Parak, Fachbereich Physik, Philipps-Universtität Marburg, Renthof 7, 35037 Marburg, Germany and Philipps-Universtität Marburg,Technological Platform "Semiconductor Nanocrystals"
Correspondence to: Nadja C. Bigall ([email protected]) Wolfgang J. Parak ([email protected])
Source: Protocol Exchange (2012) doi:10.1038/protex.2012.043. Originally published online 28 August 2012.