No abstract

A facile approach to prepare CdSe/ZnS quantum dot-encapsulated chitosan hybrid nanospheres (CS-QD) is developed by utilizing ethanol-aided counterion complexation in aqueous solution. The obtained CS-QD hybrid nanospheres have not only the loading space provided by the chitosan spherical matrix for loading multiply QDs but also unique fluorescent properties provided by the encapsulated QDs. Moreover, these hybrid nanospheres possess good biocompatibility and optical stability in physiological environment. It is demonstrated that CS-QD hybrid nanospheres can be internalized by tumor cells and hence act as labeling agent in cell imaging by optical microscopy. In addition, CS-QD hybrid nanospheres can be used for imaging of tumor in tumor-bearing mice via intratumoral administration and can accumulate at tumor site via the blood circulation based on intravenous injection. Thus, on the one hand, chitosan nanospheres provide the protection in both colloidal and optical stability arising from QDs and offer biocompatibility. On the other hand, the encapsulated QDs light up polymer nanospheres and display the fate of polymer nanospheres in cells and bodies.

An ultra-high relaxivity of MRI contrast agent was fabricated by controlling the clustering of iron oxide nanoparticles confined in a hydrophilic polymer.

The proposed experiment can help students to understand the factors involved in the stability of gold nanoparticles (Au NPs) by exploring the adsorption interaction between Au NPs and various substances. The students in this study found that the surface plasmon resonance band of Au NP solutions underwent a red shift (i.e., from 520 to 650 nm) because of NaCl-induced aggregation caused by the elimination of the repulsive electrostatic force. In addition, a sufficient amount of bovine serum albumin molecules (29.4 nM) adsorbed on the surface of Au NPs (1.8 nM) through electrostatic interactions provides steric barriers that hinder electrolyte-induced aggregation. This experiment was performed in the fall 2014 semester to improve the recognition of nanoscale science and engineering concepts of undergraduates.

We present here a facile strategy for constructing Dextran-poly(3-acrylamidophenylboronic acid) (Dextran-PAPBA) nanoparticles (NPs) through a radical polymerization of the monomer 3-acrylamidophenylboronic acid (APBA) bound by dextran via a boronic acid-diol reaction in aqueous solution. The synthesized Dextran-PAPBA NPs are stable in a wide pH range. Their size and composition are tunable by varying the feeding molar ratio of the glucopyranoside unit in dextran to APBA. Additionally, the NPs have good biocompatibility and cell membrane penetrability, as demonstrated by in vitro experiments. Doxorubicin was encapsulated in the NPs and exhibited a sustained and strongly pH-dependent release profile that would greatly favor the in vivo drug delivery performance of the NPs. The facility of this strategy together with the tunable boron content and outstanding drug release and cellular membrane crossing performance of the produced NPs should greatly boost their applications in boron neutron capture therapy (BNCT) and chemotherapy for cancer treatment.