Porous Si improves the controlled release of medicines.
Video courtesy of the European Patent Office and Leigh Canham.
Micrometer particles are being filled and then used to delay or controll the release of drugs, highly porous films are being used as a scaffolding to grow skin for skin transplants, as well as new medical imaging applications to prove efficacy and success rates.
Loading Medicines into Silicon Particles
Building a bottle around a ship. A molecular or nanoparticle payload can be trapped by partial oxidation of the porous Si host layer. Oxidation produces a volume expansion (Si to SiO2) that shrinks the pores, locking the payload in place.
Anglin EJ, Cheng L, Freeman WR, Sailor MJ. Porous silicon in drug delivery devices and materials Adv Drug Deliv Rev. 2008;9:1266–1277
The human body is a wonderful and dynamic organism. As viruses, contaminates, or even medicines enter the body, defence mechanisms are triggered and unwanted intruders are battled or filtered out as quick as possible. This becomes difficult for the medicines that are trying to help fight against tumors, cysts and other abnormalities that have assimilated and become one with the body.
Tumors grow rapidly within the body building networks of blood vessels to feed their hunger while at the same time deforming the healthy tissues in its vicinity. Fortunately, because these blood vessels grow so quickly their walls are permeable and suseptible to nanotherapeutics. As drug-filled porous silicon carriers enter the body, a portion will be filtered out of the body, but a portion will be sucked in by the tumor. The delayed release of medicine ensures that the drug payload is actually released at its target.
This is an interesting study done showing the success of porous Silicon against cancer.
courtesy of Dr. Ester Segal at the Technion Israel Institue of Technology.
Zilony N., Tzur-Balter A., Segal E., Shefi O., Bombarding Cancer: Biolistic Delivery of therapeutics using Porous Si Carriers, Scientific Reports, doi:10.1038/srep02499 (2013).
Medicinal Release vs. Time
The link shows an interesting study over different therapuetics and their dissolution rate within the human body.
Depending on shape and porosity of the Silicon carriers. Medicinal release can be Extended to days, weeks, months or even a year.
For treatments or therapies that are difficult and/or need time before healing occurs. Porous Silicon can help to reduce hospital visits or the amount of painful treatments saving the patient and hospital time and cost.
courtesy of Dr. Alessandro Grattoni of the department of nanomedicine at the Houston Methodist Research Institute.
Fine D, Grattoni A, Goodall R, et al. Silicon micro- and nanofabrication for medicine. Adv Healthc Mater 2013; 2: 632–666
Bio-Compatible and Safe
Silicon, a GRAS (Generally Recognized as Safe) material, has proven to not only be non-toxic but when nanostructured is completely biocompatible with the human body and disolves within bodily fluids. This charachteristic is very interesting for controlling the release of medicinal drugs taken either topically, transdermally, or even orally.
Slow dissolution of porous siliicon within the human body enables prescriptions of non soluble medicines, thus opening up possibilities for a wider range of drugs to be administered. Exact doses or softer, dilute doses can then be used in a controlled manner, sustained over time as well as better targeted to prevent harm to healthy parts of the body. This helps conquer chronic diseases such as cardiovascular and diabetes, or even cancer while at the same time easing the situation for patients.