BioMagnetic Solutions

CELLSEARCH® The Tools that fueled the new world of Circulating Tumor Cells by Paul A. Liberti, PhD CEO, CSO – BioMagnetic Solutions

The Tools and Individuals that Fueled the New World of Circulating Tumor Cells

In 1975, Gullino and Butler at the National Cancer Institute (NCI) made perhaps the first definitive measurements of tumor cells shedding into peripheral blood.  The significance of that seminal work did not reach its potential until nearly 30+ years later, primarily because the tools that could move it forward did not exist.  Those tools are embodied in the CELLSEARCH® system for detecting and characterizing Circulating Tumor Cells, a product of Veridex, a Johnson & Johnson Division now part of Janssen Diagnostics/Janssen Oncology.  The genesis of CELLSEARCH® that geminated the world wide interest in Circulating Tumor Cells [CTCs] is worth recording.

In the late 1980s, at Immunicon in Philadelphia, we were doing collaboration with Temple University hematologist Dr. Ken Mangan on purging B Lymphoma cells from marrow and blood.  At Immunicon, we were using a magnetic separation system I had developed that was based on highly magnetic liquids (tagged with Mabs) that I had patented in concert with an ultra-high gradient magnetic device with two of my scientists, Youzhou Wang & Weixing Tang.  We were labeling a B cell line, spiking cells into blood and seeing  (by PCR) how effectively we could retrieve them.  As we kept lowering the spike level, we did some calculations using Poisson statistics and realized that we would effectively have to analyze the entire product of separation to determine with any accuracy if any cells were left.  Accordingly, we began looking at what we were purging rather than what might be left in the sample.  To our great surprise, we found that we could repeatedly retrieve labeled cells that were spiked at the level of 1 or 2 cells per […]

By |November 22nd, 2013|BioMagnetic Solutions|0 Comments

Nano particles vs. Micro beads by Paul A. Liberti, PhD CEO & CSO BioMagnetic Solutions

Nano particles vs. Micro beads

In the mid-1980s, John Kemshead and John Ugelstad came to visit me at Thomas Jefferson Medical College in Philadelphia where I had just founded Immunicon.  Kemshead, a close friend and colleague from our days together in Mill Hill**, was working at The Imperial Cancer Fund.  Ugelstad, a Norwegian chemist had recently invented a process to produce uniform polymer micro-beads and had developed an ingenious method to load them up with magnetite crystals rendering them highly magnetic.  John and John had been collaborating for some time with Kemshead ‘teaching’ Ugelstad (his words) what surfaces were required to be compatible with biological systems and what kind of receptors (primarily MAbs) needed to be attached.  They had finally reached a point in their collaboration where they had usable beads and with them John Kemshead had just performed the first tumor (neuroblastomas) cell depletion of bone marrow. Kemshead went on to treat numerous pediatric neuroblastoma patients by marrow depletion in combination with timed chemotherapy.

The mutual interest in magnetic separation technology was based on a project we would be doing at Immunicon involving the removal of immune complexes from patients with Rheumatoid Arthritis with the goal being a new treatment approach.  I was in need of one or more separation systems.  Also I had been working on a colloidal magnetic nanoparticle that Immunicon had acquired from a Jefferson colleague, Charlie Owen.  Owen had developed a method of taking protein along with Fe+2 and Fe+3 salts solution, co-precipitating them with base and resuspending the co-precipitate with mild sonication rendering them colloidal (100-115 nm nanoparticles).  [Those weakly magnetic materials were the forerunners of the highly magnetic ferrofluids I later on developed at Immunicon.]

The four of us spent an […]

By |October 29th, 2013|BioMagnetic Solutions|0 Comments