Liver on a chip? Maybe someday, say researchers
Cell-holding scaffolds for the project are made of laser-machined polymers (polycarbonate, polyethylene terephthalate, and polyimide). Extremely small channels and pores in the polymer scaffolds are micromachined using highly precise UV excimer lasers custom designed by J P Sercel Associates (JPSA) in Hollis, N.H.
The UV laser micromachining application was developed in JPSA's Applications Laboratory. " Excimer laser micromachining is ideal for this application for a variety of reasons," says Jeffrey P. Sercel, president. "Short-wavelength UV laser energy is ideal for clean cutting, drilling, and shaping polymer and other materials that are difficult to micromachine using other technologies. Although an etching process can be used, such as reactive ion etching, UV-laser technology allows processing of materials such as polycarbonate and polycyclo-olefins that offer favorable characteristics for biomedical applications."
In process, very fine and measured amounts of material are removed as a plasma plume by photoablation with each laser pulse, leaving a cleanly sculpted pore, channel, or feature.
The large size of the UV excimer laser beam allows it to be separated into multiple beamlets through near-field imaging techniques, so multiple pores, for example, can be simultaneously bored with each laser pulse. Imaging techniques also allow submicron resolution so that nano features can be effectively controlled and shaped. Manufacturing specifications require JPSA to micromachine scaffold thickness of 250 mm and channel depth of 200 mm, with pore depth of 50 mm.
The concept of the Liver Chip was developed by a team led by Linda Griffith, professor, mechanical engineering and biological engineering, and Karel Domansky, research scientist. The Liver Chip represents a perfect example of systems biology as a model for human disease and as a tool in early drug discovery and development. Primary cells from the liver are introduced into the new technology to support development of the 3D structures of a functioning liver.
The chip is made with tiny channels that provide simulated blood flow. These channels supply the cells with the correct nutrients and hormones to promote growth of tissue architecture and function. The chip's creators are also working with industry to develop the liver chip as a tool for drug discovery and development, including drug metabolism and toxicology, simulating the liver regulation network in the lab as a model for human disease. Each year thousands of liver transplants are required but the supply does not always meet the demand. Research facilitated by the liver chip will promote a better understanding of liver health, provide insight into disease prevention and reduce the need for liver transplants.