2.MICRO AND NANO TECHNOLOGY IN MEDICINE
Micro and nanotechnology have significant applications in the biomedical area, such as drug delivery, gene therapy, novel drug synthesis, imaging, etc. In diagnostics and treatment of many disorders, micro-electro-mechanical systems (MEMS) and biocompatible electronic devices have great potentials. MEMS are formed by integration of mechanical elements, sensors, actuators and electronics on a common silicon wafer with microelectronics and micromachining technologies. Sensors collect information from the environment by measuring mechanical, thermal, biological, chemical, optical or magnetic parameters; electronics process these information and actuators respond by moving, positioning, regulating, pumping or filtering. Therefore a desired response occurs against the stresses and environment is controlled by the system.Use of nano devices in imaging is another important area especially in the detection of tumor cells. In principle, nanoparticles injected into the body detect cancer cells and bind to them. They behave as contrast agents making
the malignant area visible so that the anatomical contours of the cancer lesion can be defined. For this purpose iron- oxide nanoparticles whose surfaces were modified by amines were prepared by Shieh et al (2005) and a fast and prolonged inverse contrast effect was shown in the liver in vivo that lasted for more than 1 week. Medical applications of metallic nanoparticles were studied by different groups. For example Dua et al (2005) constructed a non- toxic, biomimetic interface for immobilization of living cells by mixing colloidal gold nanoparticles in carbon paste and studied its electrochemical exogenous effect on cell viability. Pal et al (2005) prepared gold nanoparticles in the presence of a biopolymer, sodium alginate by UV photoactivation. Carrara et al (2005)
prepared nanocom- posite materials of poly(o-anisidine) containing titanium dioxide nanoparticles, carbon black and multi-walled carbon nanotubes for biosensor applications. The synthe- sized materials were deposited in thin
films in order to investigate their impedance characteristics. Lee et al (2005) prepared ultrafine poly(acrylonitrile) (PAN) fibers containing silver nanoparticles. Silver ions in a PAN solution were reduced to produce Ag
nanoparticles and the resulting solution was electrospun into ultrafine PAN fibers. Morishita et al (2005) associated HVJ-E (hemagglutinating virus of Japan- envelope) with magnetic nanoparticles so that they can
potentially enhance its transfection efficiency in the presence of a magnetic force. It was reported that, heparin coated maghemite nano particles enhanced the transfection efficiency in the analysis of direct injection into the
mouse liver. They proposed that the systemcould potentially help overcome fundamental limitations to gene therapy in vivo.
Source:
Nanomaterials and Nanosystems for Biomedical Applications
NESRIN HASIRCI
Middle East Technical University, Faculty of Arts and Sciences, Department of Chemistry, Ankara 06531, Turkey
สมัครสมาชิก:
ส่งความคิดเห็น (Atom)
ไม่มีความคิดเห็น:
แสดงความคิดเห็น