(569g) Immuno-Liposome Nanoparticle Microarray for Detection of Circulating Tumor Cells

Immuno-Liposome Nanoparticle Microarray for Detection of
Circulating Tumor Cells

Kwang Joo Kwak^1,2, Bo Yu¹, Yun
Wu¹, Xinmei Wang¹, David J. Vanderah³, and L.
James Lee^1,2*

¹NSF Nanoscale Science and Engineering Center for Affordable Nanoengineering of Polymeric Biomedical Device (NSEC-CANPBD)

²Department of Chemical and Biomolecular
Engineering

³Biomolecular Structure and Function Group
at the Center for Advanced Research in Biotechnology (CARB), National Institute
of Standards and Technology (NIST), Rockville, Maryland 20850

The Ohio State University, Columbus, Ohio 43210

*Contact author-
E-mail: lee.31@osu.edu

Using circulating tumor cells (CTCs) in
blood as a biomarker for early cancer detection has gained a great deal of
attention in the medical field lately because such ?liquid biopsy' approach is
non-invasive and simple. Although
a number of devices have been developed for separating and characterizing CTCs
[1], including the commercially available and FDA approved CellSearch^TM
system (Veridex, Warren, NJ), it is very difficult to produce repeatable quantitative results because
of their extreme rarity, i.e. ~5 CTCs among more than 5 billions blood cells in
1 ml blood sample. Recently,
a group of researchers at Harvard Medical School developed microfluidic devices,
i.e. ?CTC chip', mediated by the interaction of CTCs and microposts [2] or CTCs
and chip surface [3] coated with antibody against epithelial cell adhesion molecule (EpCAM) under controlled laminar-flow
conditions [2]. Their approach was able to yield recovery rates of >65%
spiked cancer cells in phosphate buffered saline (PBS) at 100 cells ml^-1.
Although impressive, this result is still far away from the sensitivity
(>90% recovery rate at <10 CTCs ml^-1) required for clinic use.

In ths work, we show a novel immuno-liposome nanoparticles (ILNs)
array design with improved sensitivity and specificity of CTCs isolation comparing
to the conventional antibody approaches. Recent advances in biomimetic lipid
membranes provide opportunities to develop applications such as cellular
recognition. Novel tethered bilayer liposome nanoparticles (tBLNs) that can be
conjugated on a planar surface through a self-assembled monolayer (SAM) of a thiolipid and modified with EpCAM or therapeutic targeting antibodies are our basic
design. The antibody conjugated ILNs with a diameter around 100 nm were
tethered onto the chip surface through the post-insertion and/or biotin-avidin
linking to form an array with each site around 5-15 µm diameter. The remaining
chip surface was covered by PEG to prevent non-specific cell binding. In
comparison, a similar array made of the same antibody and PEG coating without any liposome nanoparticles was also prepared. Using the mixture of two cell lines and pre-treated 1
ml human blood sample with ?spiked' MCF-7 breast cancer cell line as model
systems, the experimental results showed that our ILN array performed better
than the antibody array and other cell separation methods. Our new approach has
potential for many important biomedical applications such as prognosis of
cancer patients and monitoring targeted therapy.

References

[1] Budd G. T., Mol.
Pharm. 6(5), 1307-1310 (2009).

[2] Nagrath S, et
al. Isolation of rare circulating tumor cells in cancer patients by microchip
technology. Nature. 450: 1235 (2007).

[3] Stott S., et al.
PNAS 107(43), 18392?18397 (2010).