Devices and methods for exposing a sensor to a cell culture or microbial population are disclosed. In one embodiment, a sensor well for use with a bioreactor vessel includes a sheath； a sensing element disposed on or in a portion of the sheath； a signal transmitter disposed within at least a portion of the sheath and configured to provide signals to and/or receive signals from the sensing element and provide signals to and/or receive signals from a sensor controller； a connector configured to attach the sensor well to a portion of a bioreactor vessel, the connector including an aperture through which the sheath can be deployed into the bioreactor vessel； and a collapsible bellows which houses the sheath when in an undeployed position, the bellows coupled to one end of the sheath, the bellows, the connector, and the sheath configured to form at least a portion of a hermetically sealable and sterilizable enclosure.
