Abstract: Embodiments of the presently disclosed subject matter provide biomimetic cell culture substrates comprising highly tunable patterned polymer nanofiber matrices capable of modulating expression of critical self-renewal factors and markers of cell-cell interaction to maintain stemness of human mesenchymal stem cells in vitro. Embodiments of the presently-disclosed subject matter also provide scalable, highly repeatable methods of making biomimetic cell culture substrates by hot pressing thermoplastic polymer films into femtosecond laser-ablated nanopore molds to form patterned polymer nanofiber matrices on flat thermoplastic substrates.

Abstract: A semipermeable ultrathin polymer membrane comprises a substantially optically transparent polymer film having a surface area to thickness ratio of at least 1,000,000:1, and an array of precisely spatially ordered pores of a user-selected diameter defined therethrough. Such membranes can be fabricated by providing a mold having a patterned array of nanoholes femtosecond laser ablated in a surface thereof; applying a first polymer solution onto the mold surface so that the first polymer solution infiltrates the nanoholes; allowing the first polymer solution to dry and form a replica of the mold having a plurality of freestanding nanoneedles extending from a surface of the replica; removing the replica from the mold; coating the replica surface with a second polymer solution; drying the second polymer solution to form a porous polymer film; and dissolving the replica in a solvent to release the film from the replica as a semipermeable ultrathin polymer membrane.

Abstract: A method for modifying the wettability of a surface of an object can comprise forming on the surface of the object one or more arrays of nanofibers, wherein the one or more arrays of nanofibers includes nanofibers spaced along an X-axis and a Y-axis at the same or different intervals along either axis, the one or more arrays of nanofibers is integral with the object, and the nanofibers all have a base portion that is substantially normal to the surface. The intervals, diameter, and length of the nanofibers of the one or more arrays of nanofibers are selected so that the wettability of the surface for one or more predetermined liquids is increased or decreased relative to the wettability of the surface in the absence of the array of nanofibers.

Abstract: A tunable nanofiber filter device can include a filter housing defining an interior space, the housing having defined therein and inlet and an outlet, each in fluid communication with the interior space, and a plurality of filter laminas disposed within the interior space, each filter lamina including an upper surface, a lower surface, and an aperture defined therethrough. The plurality of filter laminas can be arranged in a stack wherein the opposing surfaces of adjacent filter laminas define a portion of an interlaminar flow space extending between the opposing surfaces. The flow space can be in fluid communication with the apertures of corresponding adjacent filter laminas to form a continuous flow passage extending through the lamina stack from the inlet to the outlet. An array nanofibers can extend into the flow passage from a portion of each filter lamina such that a fluid flowed through the flow passage flows across a portion of said array.