{"id":1685,"date":"2020-12-16T03:46:53","date_gmt":"2020-12-16T08:46:53","guid":{"rendered":"http:\/\/www.bocsci.com\/blog\/?p=1685"},"modified":"2020-12-27T21:01:57","modified_gmt":"2020-12-28T02:01:57","slug":"magnetic-beads-mbs-for-hyperthermia","status":"publish","type":"post","link":"https:\/\/www.bocsci.com\/blog\/magnetic-beads-mbs-for-hyperthermia\/","title":{"rendered":"Magnetic Beads (MBs) for Hyperthermia"},"content":{"rendered":"

Conventional treatments, like surgery, irradiation, chemotherapy, or combinations of them, are often compromised\u00a0by systemic toxicity due to\u00a0lack of\u00a0tumor specificity. Hyperthermia is a promising approach to treat\u00a0cancer\u00a0because cancer\u00a0cells are susceptible to heat, and when\u00a0raising the\u00a0temperature to 43 \u00b0C for 30 mins or more, the apoptosis of cancer cells can be triggered. One of the technical problems\u00a0in hyperthermia is to realize a uniform heating,\u00a0that is, only the tumor site is heated to the required temperature and other areas are not damaged. This problem can be\u00a0tackled by using magnetic beads (MBs)<\/a>, which can be accumulated\u00a0only in the tumor region and then heated by external\u00a0AC magnetic field.<\/p>\n

C<\/b><\/strong>ategories of Hyperthermia<\/b><\/strong><\/p>\n

According to the treated region, hyperthermia can be classified into three types:<\/p>\n

\"\"<\/a><\/p>\n

The first type of hyperthermia is always achieved by using thermal chambers or blankets.\u00a0As regards to the partial hyperthermia, which is often applied to treat locally advanced cancer by perfusion or microwaves.The local hyperthermia\u00a0is mainly used for smaller organs.<\/p>\n

Heat Generation <\/b><\/strong>M<\/b><\/strong>echanisms of Magnetic Hyperthermia <\/b><\/strong><\/p>\n

As well know, the interaction of electromagnetic fields and\u00a0substance generally leads to the generation of heat. Magnetic hyperthermia utilizes\u00a0the heat generated by the exposure of magnetic beads to an AC magnetic field. The amount of heat generated\u00a0per unit\u00a0volume can be\u00a0calculated by the following equation:<\/p>\n

\"\"<\/a><\/p>\n

where\u00a0\u03bc<\/b><\/strong>0<\/b><\/sub><\/strong>\u00a0is the permeability of free space,\u00a0f <\/b><\/strong>is the frequency, H <\/b><\/strong>is the amplitude. From this equation, we can conclude that the calculation principle\u00a0of heat\u00a0largely depends on the characteristics of the electromagnetic field, including\u00a0frequency and amplitude, as well as the matter properties. However, this formula ignores other possible mechanisms for magnetically inductive heating, such as eddy current heating and ferromagnetic resonance, which are of minor relevance\u00a0in the present context. The MBs used for hyperthermia normally exhibits poor electroconductivity and are much too small to incorporate eddy current loop. Ferromagnetic resonance effects may become\u00a0relevant,\u00a0but it only make sense\u00a0at frequencies far beyond the general frequency.<\/p>\n

P<\/b><\/strong>arameters Affecting the Heat<\/b><\/strong><\/b><\/p>\n\n\n\n\n\n\n\n
Extrinsic parameters<\/b><\/strong><\/td>\nIntrinsic parameters<\/b><\/strong><\/td>\n<\/tr>\n
Magnetic field amplitude<\/td>\nParticle anisotropy<\/td>\n<\/tr>\n
Magnetic field frequency<\/td>\nnature of the surface coating<\/td>\n<\/tr>\n
Viscosity of the fluid<\/td>\nMBs concentration<\/td>\n<\/tr>\n
<\/td>\nSize & surface effects of MBs<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n

Basic Requisites of magnetic beads (MBs)<\/a> for Hyperthermia <\/b><\/strong><\/p>\n