One aspect of the present invention relates to a silicon nanoporous membrane for oxygenating blood. The nanoporous membrane includes a first major surface, a second major surface, and a plurality of pores extending between the first and second major surfaces. The first major surface is for contacting a gas. The second major surface is for contacting blood and is oppositely disposed from said first major surface. The first and second major surfaces define a membrane thickness. Each of the pores is defined by a length, a width, and a height. Each of the pores is separated by a uniform interpore distance.