Nanoimplant for precise drug delivery

An implant has been developed for targeted delivery and long-term release of drugs

Oleg Lischuk, N+1

American scientists have developed a universal implant for the long-term release of drugs at a given point in the body, for example, in a tumor. The device is described in the Journal of Biomedical Nanotechnology (Hood et al., Nanochannel Implants for Minimally-Invasive Insertion and Intratumoral Delivery).

Cancer chemotherapy drugs are highly toxic and have many systemic side effects. In addition to the undesirable effect on the entire body, this limits their doses, which is why the concentration of the drug in the tumor may be insufficient. In addition, chemotherapy requires regular hospitalizations. Therefore, many research teams are looking for ways to target drug delivery. Most experimental methods involve direct infusion of drugs into the tumor, binding of drugs with biodegradable polymers or nanoparticles. Their main disadvantages are the difficulty of ensuring a uniform concentration of the drug for a long time or the use of unsafe materials.

Employees of the Houston Methodist Research Institute and the University of Texas have developed an implantable drug delivery system that regulates their release itself. It is a three–millimeter cylindrical capsule made of stainless steel or polyesteresterketone, filled with 2.5-3 microliters of the drug solution. On one side it is sealed with silicone, and on the other there is a silicon membrane with about five thousand 20-nanometer channels. Such a diameter is only slightly larger than the size of drug molecules and ensures their gradual diffusion with decreasing concentration in the capsule area.

The implant and its nanochannels
Here and below are drawings from an article in the Journal of Biomedical Nanotechnology

The device is inserted into the tumor tissue using a thick hollow needle (trocar). The use of metal or polymer for the shell depends on the intended methods of examination: steel is clearly visible during radiography and computed tomography, and polyesteresterketone is compatible with MRI.

Method of introduction and device of the system

The system was tested in vitro and on mice with artificially induced tumors. In the experiments, the chemotherapy drug doxorubicin, antitumor monoclonal antibodies OX86 and FGK45, immunoglobulin associated with a fluorescent dye, and gadopentetic acid, a contrast agent for MRI, were used. Observations have shown that the implant provides a uniform release of drugs for several days to two weeks, without creating significant concentrations of the drug throughout the body.

Doxorubicin release schedule

According to one of the authors of the work Lyle Hood, larger versions of the device can be used for long-term (up to a year) therapy of HIV infection and autoimmune diseases. Currently, the developers are working on a 3D-printed version of the system, which self-decomposes after the release of the drug.

Previously, it was proposed to use nanomycelles, thermoregulated and magnetically sensitive bacteria, diatoms, magnetic "carpets" and polymer nanoparticles coated with platelet membranes for targeted drug delivery.

Portal "Eternal youth" http://vechnayamolodost.ru  05.12.2016