TECHNOLOGY FOCUS - MECHANICAL ENGINEERING - Preferred Components: The porous material is at least a portion of a wall (105), cover, floor, filter, window, or tube of the bioreactor. The gas-permeable porous material is further selectively permeable to photoradiation, visible radiation, UV radiation, cells, organisms, and/or cellular components. The porous material may be transparent. It may also be hydrophobic. The porous material is a sterile barrier. It is in fluid communication with a gas within the bioreactor. The porous material is at least partially in a form of a panel, a monolith (155), a cylindrical vessel, a cylindrical tube, and/or a hemisphere. The porous material has a pore size of 500 nm. It comprises pores having a diameter greater than 0.5 nm. A structural component of the bioreactor comprises the gas-permeable porous material. Structural components and/or functional components provide a mechanism for sanitization and/or sterilization, contamination prevention, monoseptic holding or processing, culture agitation or circulation, temperature detection and/or temperature control, gas delivery and/or gas removal, dissolved gas detection and/or control, pH detection and/or control, photoradiation delivery, photoradiation detection and/or quantification, reorientation of a portion of the bioreactor relative to a photoradiation source, liquid delivery and/or removal, nutrient detection and/or delivery, waste removal, cell and organism delivery and/or removal, gas harvesting, or product harvesting.    TECHNOLOGY FOCUS - ORGANIC CHEMISTRY - Preferred Materials: The porous material may be permeable to acetylene, ethane, ethylene, ethylene oxide, formaldehyde, methane, methyl chloride, gaseous fluorocarbons, or volatile organic molecules.    TECHNOLOGY FOCUS - CERAMICS AND GLASS - Preferred Materials: The porous material is an aerogel or a silica aerogel. It is made by a sol-gel process.    TECHNOLOGY FOCUS - INORGANIC CHEMISTRY - Preferred Materials: The porous material may be permeable to air, ammonia, argon, bromine, carbon dioxide (CO2), carbon monoxide (CO), chlorine, helium, hydrogen, hydrogen chloride, hydrogen cyanide (HCN), hydrogen iodide, hydrogen sulfide, nitric oxide (NO), nitrogen, nitrous oxide (N2O), oxygen, or sulfur dioxide.    TECHNOLOGY FOCUS - BIOLOGY - Preferred Cells: The cell is a bacterial, animal, plant, fungal, algal, or mammalian cell.