Intangible assets

3 Months Ended

Mar. 31, 2013

Intangible assets [Abstract]

Intangible assets

4. Intangible assets

At March 31, 2013 and December 31, 2012, intangible assets and intangible assets net of amortization were comprised of the following:

	March 31, 2013 (unaudited)			December 31, 2012
Intangible assets	$	25,702,909		$	25,702,909
Accumulated amortization		(5,858,690	)		(5,216,117	)
Intangible assets, net	$	19,844,219		$	20,486,792

BioTime amortizes its intangible assets over an estimated period of 10 years on a straight line basis.  BioTime recognized $642,573 and $535,737 in amortization expense of intangible assets during the three months ended March 31, 2013 and 2012, respectively.