Semipermeable ultrathin polymer membranes

A method of fabricating a semipermeable polymer membrane, comprising:

• providing a mold having a patterned array of nanoholes femtosecond laser ablated in a surface of said mold;
• applying a first polymer solution onto said mold surface whereby said first polymer solution infiltrates said nanoholes;
• drying said first polymer solution to form a negative replica of said mold, said replica having a first surface, a second surface opposite the first surface, and a plurality of freestanding nanoneedles extending a nanoneedle height from said first surface;
• removing said replica from said mold;
• coating said first replica surface with a second polymer solution, whereby said first replica surface is covered with a layer of said second polymer solution having a thickness less than said nanoneedle height such that said nanoneedles extend through said layer;
• drying said second polymer solution to form a porous polymer film;
• and
• dissolving said replica in a solvent to release said film from said replica.

A microfluidic device for studying cell biology in vitro, comprising:

• a first microfluidic layer having an upper surface, a lower surface, an apical chamber defined in said lower surface, and an aperture extending from said upper surface to said apical chamber, said aperture in fluid communication with said apical chamber;
• a second microfluidic layer having an upper surface, a lower surface, and at least one basal chamber defined in said upper surface;
• and
• an optically transparent, biocompatible polymer nanofilm having an upper surface, a lower surface, a surface area to thickness ratio of at least 1,000,000:1, and an ordered array of micrometric pores defined through said film;
• wherein the upper surface of said film contacts the lower surface of said first microfluidic layer, the lower surface of said film contacts the upper surface of said second microfluidic layer, and said apical chamber is in fluid communication with said basal chamber through said pores.