There has been much

recent activity directed toward engineering devices powered by biological

structures from the molecular to the tissue level. Since individual molecular

motors provide only miniscule amounts of work, the actions of millions or more

must be harnessed in parallel to result in significant activity in the

macroscopic world. The prospects of exploiting natural massively parallel motor

assemblies, such as muscle cells, are very attractive since the production,

organization, and manipulation of the motors from nanometer to millimeter length

scales are coordinated by complex biological molecular machinery refined over

millions of years of natural selection. Engineering muscle cells onto microchips

is an initial but critical step towards fabricating autonomous intelligent

hybrid micromachines since cells have extremely elaborate ways of

self-sustainment, regulation and assembly.

The use of mature

muscle tissues from animals on these devices is impractical and inefficient, as

the tissues must be dissected and incorporated into each device by hand with

crude interfaces between the biological tissues and inorganic materials.

Integration of muscle with microfabricated structures would be optimally

achieved through self-assembling muscle cells on MEMS. However, the unique anisotropic,

structural, and contractile characteristics of muscle bundles complicate the

construction of muscle-powered MEMS structures. Specifically, there exist three

interrelated outstanding problems: 1) to spatially and selectively direct the

growth and maturation of cells on microfabricated substrates, 2) to control the

tight binding of differentiated muscle bundles with the surrounding mechanical

structures, and 3) while maintaining the tight binding in specified locations,

enable the cells and the resultant hybrid structure freedom to

move.

To address these

problems, we have devised a novel system for the creation of self-assembled

muscle-powered microdevices through the manipulation of material interfaces and

phase. Two types of devices will be presented to illuminate the potential of

this fabrication system. One type allows us to characterize in situ the

mechanical properties of the muscle. The mechanical properties of the neonatal

ventricular myocytes 1-3-day-old Sprague-Dawley rats (NRVMs), such as

substrate-induced stress (2-2.5 kPa) and Young’s Modulus (~40 kPa), have been

measured in a direct way. Another has resulted in the first self-assembled

microrobots which move autonomously in response to the contraction of muscle

bundles. Hybrid microrobots with the size of 160 μm can move at speeds of

10-50μm/s for more than 4 hours.

A wide range of

MEMS devices, electronic circuits, and patternable materials can be seamlessly

integrated with a variety of cell types via our established system. The union of

top-down MEMS fabricated structures with those synthesized, organized, and

maintained by the bottom-up processes of biology could create devices with

properties unattainable by either alone.

席建忠，1992-1996年于北京理工大学攻读化工专业，1997-2000年于清华大学攻读分子细胞生物，2000-2002年在康奈尔大学攻读生物工程专业，2001年底随同导师转往加州大学洛杉矶分校（英文缩写为UCLA），主要攻读生物力学、生物材料与组织工程专业，副修分子与细胞生物工程专业，2004年取得生物医学工程博士学位，同时还获得UCLA生物医学工程系年度唯一的优秀博士毕业生称号。2005年3月获得中国教育部2004年国家优秀自费留学生奖。在美国求学期间曾参加过十多次国际学术会议，并做过多次学术报告。2005年7月，他成为北大工学院第一位“优秀青年人才引进计划”的特聘学者。