Macromolecular Amphiphiles Polymer Synthesis Diblock Copolymers Triblock Copolymers Dendron Copolymers Bio-Inspired Hybrid Materials Mesoporous Materials High-Temperature Ceramics Hybrids from Nanoparticles Mesoporous Metals Thin Films Fuel Cell Materials Functional Core-Shell Silica Particles Fluorescent C Dot Particles Probes for Nanobiotechnology Laboratories on Particles Nanophotonic Materials Complex Polymeric Materials Mobile Hydrogels Complex Fluids filler
image
Research Areas of Interest Links
grouphoto

Silica Nanoparticles as Biological Probes

The core-shell architecture of the C dot is ideally suited to the development of multifunctional probes for biology.

In collaboration with the Baird Group here at Cornell, we have demonstrated antibody-mediated labeling with Rat Basophilic Leukemia Mast Cells using the FCeRI cell surface receptor for IgE as shown below.

Confocal Microscopy

In addition to labeling, we have developed a class of sensor particles based on the core-shell C Dot architecture, known as C Dot sensors.

These particles use the core dye as an internal reference, allowing quantitative concentration measurements to be performed.

By placing the sensor dye in the surface shell, the maximum possible surface area is exposed for interaction with the environment

Core-shell sensors
Sensors in cells
We have demonstrated ratiometric pH sensing in RBL cells using a FITC/TRITC labeled particle, as shown in the confocal images at left. The individual reference and sensor signals were collected, compared for each pixel and analyzed to yield the false-spectrum image at right showing the pH in various intracellular vesicles in a mast cell.

References:

J. Choi, A. Burns, R. Williams, Z. Zhou, A. Flesken-Nikitin, W. Zipfel, U. Wiesner, A. Niktin. "Core-shell silica nanoparticles as fluorescent labels for nanomedicine" Journal of Biomedical Optics, 12(6) (2007) 064007-(1-11)

A. Burns H. Ow, U. Wiesner. "Fluorescent core-shell silica nanoparticles: towards 'Lab on a particle' architectures for nanobiotechnology" Chemical Society Reviews, 35, 2006, 1028-1042

A. Burns, P. Sengupta, T. Zedayko, B. Baird, U. Wiesner. "Core-Shell Fluorescent Silica Nanoparticles for Chemical Sensing: Towards Single Particle Laboratories" Small, 2(6) 2006, 723-726

E. Herz, A. Burns, S. Lee, P. Sengupta, D. Bonner, H. Ow, C. Liddell, B. Baird, U. Wiesner. " Fluorescent core-shell silica nanoparticles: an alternative radiative materials platform", Proceedings of the SPIE Vol. 6096: Colloidal Quantum Dots for Biomedical Applications, 2006, 1-12

H. Ow, D. Larson, M. Srivastava, B. Baird, W. Webb, U. Wiesner,"Bright and Stable Core-Shell Fluorescent Silica Nanoparticles", Nano Letters 5(1), 2005, 113-117

All images and text Copyright 2008

Wiesner Research Group - Cornell University

In vivo probes for Nanomedicine:

Further, we have begun to study the biodistribution and biocompatibility of these nanoparticles in living systems. This work has shown the particles to be non-toxic in mice, and we have demonstrated in vivo imaging of the particles both in the bloodsteram as well as within cells.

The images at right show 30nm particles in the bloodstream via multiphoton microscpy (top, red), and spontaneously endocytosed by mouse prostate carcinoma cells via TAT cell-penetrating peptides conjugated to the particle surface (bottom, red).