A bioreactor chamber assembly comprising: at least a base and a cap configured to be coupled together to define a chamber body having a wall that defines an internal chamber to accommodate a biological sample; characterised in that: the base and cap each comprising a plurality of respective interengaging flanges (113, 123) to allow the base and cap to be releasably coupled and locked together axially relative to a longitudinal axis bisecting the base and cap by rotation of at least one of the base and cap about the longitudinal axis; the base and cap each further comprising a respective sealing surface (116M, 126M) that may be drawn and mated together axially via an interference fit arrangement by said rotation to provide a fluid tight seal when the base and cap are locked together axially; a liquid inlet to allow a liquid to flow into the internal chamber; a liquid outlet to allow a liquid to flow out from the internal chamber and being separate to the liquid inlet; a gas inlet to allow a gas to flow into the internal chamber; and a gas outlet (103 OUT) to allow a gas to flow out from the internal chamber and being separate to the gas inlet; wherein the liquid inlet and outlet are positioned at an axial height lower than an axial height of the gas inlet and outlet relative to a longitudinal axis of the chamber assembly extending through the base and cap such that a gas-liquid interface may be created within the internal chamber between the liquid and the gas; wherein the liquid inlet and outlet are positioned at substantially the same axial height at the chamber wall to assist maintaining the axial position of the gas-liquid interface; the chamber assembly further comprising at least one sample support mount provided at a region of the chamber wall to mount the biological sample at a position relative to the longitudinal axial such that the biological sample is maintainable in contact with the gas-liquid interface. at least a base and a cap configured to be coupled together to define a chamber body having a wall that defines an internal chamber to accommodate a biological sample; characterised in that: the base and cap each comprising a plurality of respective interengaging flanges (113, 123) to allow the base and cap to be releasably coupled and locked together axially relative to a longitudinal axis bisecting the base and cap by rotation of at least one of the base and cap about the longitudinal axis; the base and cap each further comprising a respective sealing surface (116M, 126M) that may be drawn and mated together axially via an interference fit arrangement by said rotation to provide a fluid tight seal when the base and cap are locked together axially; a liquid inlet to allow a liquid to flow into the internal chamber; a liquid outlet to allow a liquid to flow out from the internal chamber and being separate to the liquid inlet; a gas inlet to allow a gas to flow into the internal chamber; and a gas outlet (103 OUT) to allow a gas to flow out from the internal chamber and being separate to the gas inlet; wherein the liquid inlet and outlet are positioned at an axial height lower than an axial height of the gas inlet and outlet relative to a longitudinal axis of the chamber assembly extending through the base and cap such that a gas-liquid interface may be created within the internal chamber between the liquid and the gas; wherein the liquid inlet and outlet are positioned at substantially the same axial height at the chamber wall to assist maintaining the axial position of the gas-liquid interface; the chamber assembly further comprising at least one sample support mount provided at a region of the chamber wall to mount the biological sample at a position relative to the longitudinal axial such that the biological sample is maintainable in contact with the gas-liquid interface. the base and cap each comprising a plurality of respective interengaging flanges (113, 123) to allow the base and cap to be releasably coupled and locked together axially relative to a longitudinal axis bisecting the base and cap by rotation of at least one of the base and cap about the longitudinal axis; the base and cap each further comprising a respective sealing surface (116M, 126M) that may be drawn and mated together axially via an interference fit arrangement by said rotation to provide a fluid tight seal when the base and cap are locked together axially; a liquid inlet to allow a liquid to flow into the internal chamber; a liquid outlet to allow a liquid to flow out from the internal chamber and being separate to the liquid inlet; a gas inlet to allow a gas to flow into the internal chamber; and a gas outlet (103 OUT) to allow a gas to flow out from the internal chamber and being separate to the gas inlet; wherein the liquid inlet and outlet are positioned at an axial height lower than an axial height of the gas inlet and outlet relative to a longitudinal axis of the chamber assembly extending through the base and cap such that a gas-liquid interface may be created within the internal chamber between the liquid and the gas; wherein the liquid inlet and outlet are positioned at substantially the same axial height at the chamber wall to assist maintaining the axial position of the gas-liquid interface; the chamber assembly further comprising at least one sample support mount provided at a region of the chamber wall to mount the biological sample at a position relative to the longitudinal axial such that the biological sample is maintainable in contact with the gas-liquid interface.