Electrochemical anodization of titanium produces uniform titania nanotube tops
"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.
When the pore size is smaller than the molecule itself, the molecule does not exit through the pore.
No medication is delivered.
When the pore size is sufficiently large that molecules freely diffuse through the membrane, the rate of delivery decreases as the concentration equilibrates.
Medication is delivered at an uneven rate, potentially creating unnecessary side effects and limiting efficacy.
When the pore size matches that of the molecule, constrained diffusion produces constant-rate release even as the concentration equilibrates across the membrane.
Medication is delivered at an even rate that eliminates concentration variability, potentially minimizing side effects and maximizing efficacy of treatment.
Burst Release of Molecules Much Smaller Than the Pore
NanoPortal-enabled Constant Release From Size-Matched Pores
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