Overcoming drug delivery barriers

Editor’s Note: The following is a summary of one of the talks from the 2013 Nano-bio Symposium hosted by Johns Hopkins Institute for NanoBioTechnology held May 17. This summary was written by Randall Meyer, a doctoral candidate in the biomedical engineering and a member of the Cancer Nanotechnology Training Center. Look for other symposium summaries on the INBT blog.

Nanotechnology bears a multitude of possibilities to systematically and specifically treat many well-characterized and currently untreatable diseases.  Despite this, there exist multiple barriers to its development including challenges related to delivery in the human body.

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Justin Hanes, a professor of Chemical and Biomolecular Engineering at Johns Hopkins University, highlighted some of the exciting advances that his laboratory has developed to overcoming these challenges.  According to Hanes, one of the primary functions of nanobiotechnology is to enable a therapy to be delivered to a specific location and only remain there for as long as it is needed.  He likened this idea to applying weed poison to a rose garden.  You only want to apply a little bit of poison to a targeted area, not flood the whole garden.  Unfortunately conventional cancer chemotherapy is like flooding the garden, but only 1 percent of the drug reaches the tumor.  Hanes stated the goal of his work is to flip that so that all but 1 percent of the drug makes it to the site of delivery.

With that in mind, Hanes summarized two stories from his lab of ideas that are successfully being translated from bench to bedside.  One therapy involves the use of custom designed nanoparticles that are capable of penetrating the mucus layers of various human tissues to enable a controlled release of drug into the body.  The second therapy involves the use of injectable particles to the eye that inhibit blood vessel formation,  which is related to diseases such as macular degeneration.

These therapies are being developed by biotech companies launched by Hanes, GrayBug and Kala Pharmaceuticals.

INBT researchers use LEGO to study what happens inside lab-on-a-chip devices

Johns Hopkins engineers are using a popular children’s toy to help them visualize the behavior of particles, cells and molecules in environments too small to see with the naked eye. These researchers are arranging little LEGO pieces shaped like pegs to recreate microscopic activity taking place inside lab-on-a-chip devices at a scale they can more easily observe. These lab-on-a-chip devices, also known as microfluidic arrays, are commonly used to sort tiny samples by size, shape or composition, but the minuscule forces at work at such a small magnitude are difficult to measure. To solve this small problem, the Johns Hopkins engineers decided to think big.

Led by Joelle Frechette and German Drazer, both assistant professors of chemical and biomolecular engineering in the Whiting School of Engineering, the team used beads just a few millimeters in diameter, an aquarium filled with goopy glycerol and the LEGO pieces arranged on a LEGO board to unlock mysteries occurring at the micro- or nanoscale level. Their observations could offer clues on how to improve the design and fabrication of lab-on-a-chip technology. Their study concerning this technique was published in the August 14 issue of Physical Review Letters. Both Drazer and Frechette are affiliated faculty members of Johns Hopkins Institute for NanoBioTechnology.

The idea for this project comes from the concept of “dimensional analysis,” in which a process is studied at a different size and time scale while keeping the governing principles the same. [Read more...]