Electrochemical anodization of titanium produces uniform titania nanotube tops

The Goldilocks Effect

"This porridge is too hot!" Goldilocks exclaimed.
"This porridge is too cold," Goldilocks said.
"Ahhh, this porridge is just right," Goldilocks said happily.

Under standard diffusion conditions, the more drug there is inside the reservoir, the faster it comes out, leading to falling release rates over time. On the other hand, in NanoPortal implants, nanotube pore sizes are similar in size to the drug molecules themselves, and thus the motion of drug molecules is dominated by interactions with the nanotube surface, creating conditions wherein the diffusion of drug molecules may not depend on the amount of drug in the reservoir. This can result in constant release rates over time.

The Pore Is Too Small

No Molecules Can Escape

  • Zero Release

    When the pore size is smaller than the molecule itself, the molecule does not exit through the pore.

  • Poor Delivery Profile

    No medication is delivered.

The Pore is Too Big

Molecules Exit Too Fast Too Soon

  • Burst Release

    When the pore size is sufficiently large that molecules freely diffuse through the membrane, the rate of delivery decreases as the concentration equilibrates.

  • Typical delivery profile of current treatments

    Medication is delivered at an uneven rate, potentially creating unnecessary side effects and limiting efficacy.

The Pore is “Just Right”

Molecules Leave at an Even Pace

  • Constant Release

    When the pore size matches that of the molecule, constrained diffusion produces constant-rate release even as the concentration equilibrates across the membrane.

  • Optimal delivery profile

    Medication is delivered at an even rate that eliminates concentration variability, potentially minimizing side effects and maximizing efficacy of treatment.

Visualize the Molecular Release

A Tale Of Two Pores

Burst Release of Molecules Much Smaller Than the Pore

NanoPortal-enabled Constant Release From Size-Matched Pores

Tunable pore size makes drug delivery “just right”

NanoPortal incorporates a proprietary technique that enables nanometer-scale tuning to achieve pore sizes as small or large as necessary to produce constant release.

Scanning electron microscope image of NanoPortal membrane with 10nm pores

Scanning electron microscope image of NanoPortal membrane with 25nm pores

Scanning electron microscope image of NanoPortal membrane with 40nm pores