A sensor that may be used to detect the presence, amount, and/or concentration of an analyte in a medium within an animal. The sensor may include a sensor housing, an indicator element embedded within and/or covering at least a portion of the sensor housing, and a membrane over the indicator element. The membrane may reduce indicator element deterioration by preventing immune cells, such as white blood cells, from contacting the indicator element, substantially prevent transmission of light of at least a specified wavelength or range of wavelengths through the membrane, and/or permit the analyte to pass through to the indicator element. The membrane may be an opaque diffusion membrane. The sensor may include a foil. The foil may block light and/or reduce indicator element deterioration. The membrane may reduce oxidation of the indicator element.本發明係關於可用於偵測動物體內之介質中之待測物之存在、量及/或濃度之感測器。該感測器可包括感測器外殼、包埋於該感測器外殼之至少一部分內及/或覆蓋其之指示元件及於該指示元件上之膜。該膜可藉由防止諸如白血球等免疫細胞接觸該指示元件來減少指示元件劣化，實質上防止至少指定波長或波長範圍之光透射穿過該膜，及/或容許該待測物穿過到達該指示元件。該膜可為不透明擴散膜。該感測器可包括一層。該層可阻斷光及/或減少指示元件劣化。該膜可減少該指示元件之氧化。
