Topic: Development of biomedical materials for cancer treatment and bone-repairing

Speaker: Dr. Masakazu Kawashita (Graduate School of Biomedical Engineering, Tohoku University, Japan)

Time: 9:10-10:30 am, 5th,Nov.

Venue: Room 468, Lee Hsun Building, IMR CAS

More details can be found at the lab homepage of Dr. Kawashita http://www.ecei.tohoku.ac.jp/kawashita/index_e.html

Abstract:

Ceramic microspheres for embolic radiotherapy or hyperthermia

Microspheres with diameter ranging from several tens micrometers to several hundred micrometers can embolize artery to cut off nutrition supply to cancer when they are injected to the artery by catheter (arterial embolization therapy). Furthermore, radio-embolization therapy can be achieved when the microspheres can emit beta-ray with relatively short half-life, and hypothermic embolization therapy under alternating magnetic field can be also expected when the microspheres contains magnetic materials such as magnetite. In this lecture, some microspheres for intra-arterial therapy are introduced [1, 2].

Bioactive titanium with antibacterial activity under visible light irradiation

Postoperative infection is a serious problem that occurs because of the growth of bacteria on the surface of metallic orthopedic implants. Therefore, it is desirable to develop antibacterial and biocompatible metallic implants in order to minimize the incidence of surgical site infection and thus minimize the need for implant replacement. It is expected that titanium oxide (TiO2) doped with some minor elements such as nitrogen can show antibacterial activity under visible light by visible-light induced photocatalytic activity and TiO2 with specific crystalline structure can bond to living bone. In this lecture, our recent challenges to obtain bioactive titanium with visible-light induced photocatalytic activity by surface chemical treatments are introduced [3, 4].

Research on mechanism of osteoconductivity of hydroxyapatite – discussion from perspective of protein adsorption

Osteoconductivity is the ability of biomaterials to support bone formation and chemically bond to bone. Hydroxyapatite (HAp) and alpha-type alumina (a-Al2O3) are typical osteoconductive and non-osteoconductive biomaterials, respectively. Post-implantation, the biomaterials are immediately coated with, and subsequently adsorb, layers of proteins from blood and tissue fluids. Importantly, all subsequent cellular responses are dependent on the implants’ ability to adsorb protein at early time points. However, a detailed mechanism of the osteoconductive process is not yet clear. In this lecture, our recent challenges to reveal the mechanism of osteoconductivity of HAp from a view point of protein adsorption [5, 6].

References

[1] M. Kawashita et al., “Preparation of ceramic microspheres for in situ radiotherapy of deep-seated cancer”, Biomaterials, 24, 2955-2963 (2003).

[2] M. Kawashita et al., “Preparation of ferrimagnetic magnetite microspheres for in situ hyperthermic treatment of cancer”, Biomaterials, 26, 2231-2238 (2005).

[3] M. Kawashita et al., “Effect of ammonia or nitric acid treatment on surface structure, in vitro apatite formation, and visible-light photocatalytic activity of bioactive titanium metal”, Colloids Surf. B, 111, 503-508 (2013).

[4] M. Kawashita et al., “In vitro apatite formation and visible-light photocatalytic activity of Ti metal subjected to chemical and thermal treatments”, Ceram. Int., 40, 12629-12636 (2014).

[5] M. Kawashita et al., “Adsorption characteristics of bovine serum albumin onto alumina with a specific crystalline structure”, J. Mater. Sci.: Mater. Med., 25, 453-459 (2014).

[6] M. Kawashita et al., “MC3T3-E1 and RAW264.7 cell response to hydroxyapatite and alpha-type alumina adsorbed with bovine serum albumin”, J. Biomed. Mater. Res., 102A, 1880-1886 (2014).