Department of Chemical and Biological Engineering, Drexel University, Philadelphia, Pennsylvania 19104, USA.
Environ Sci Technol. 2010 Mar 1;44(5):1736-41. doi: 10.1021/es9033843.
The current method for detecting the waterborne parasite Giardia lamblia is tedious and requires a preconcentration step. We show for the first time a piezoelectric-excited millimeter-sized cantilever (PEMC) biosensor immobilized with a monoclonal antibody against G. lamblia that exhibits selective and sensitive detection of G. lamblia cysts in several water matrixes (buffer, tap, and river water) at a detection limit of 1-10 cysts/mL without a preconcentration step. The PEMC sensor is a resonance-based device that functions at a high-order mode near 1 MHz. The antibody-immobilized sensor was exposed to 1-10,000 G. lamblia cysts/mL samples in a flow arrangement. When the cysts bind to the antibody on the sensor, the resonant frequency of the cantilever sensor decreases and is recorded continuously. Positive confirmation of sensor detection responses was obtained by environmental scanning electron microscope of sensor surface after detection experiments. Higher sample flow rates (0.5-5.0 mL/min) gave higher sensor detection response. Detecting as few as 10 cysts per mL was achieved in all three water matrixes tested, and significant sensor response was obtained in 15 min. We also show the feasibility of analyzing at a low concentration of 1 cyst/mL in a one liter sample at a high flow rate of 5 mL/min.
目前检测水源寄生虫蓝氏贾第鞭毛虫的方法繁琐，需要进行预浓缩步骤。我们首次展示了一种基于压电激励的毫米级悬臂梁（PEMC）生物传感器，该传感器固定有针对 G. lamblia 的单克隆抗体，可在无需预浓缩步骤的情况下，在几种水基质（缓冲液、自来水和河水）中对 G. lamblia 包囊进行选择性和灵敏检测，检测限为 1-10 个包囊/mL。PEMC 传感器是一种基于共振的器件，工作在 1 MHz 附近的高阶模式。将抗体固定化的传感器暴露于 1-10,000 个 G. lamblia 包囊/mL 的样品中，采用流动布置。当包囊与传感器上的抗体结合时，悬臂传感器的共振频率会降低，并连续记录。通过检测实验后环境扫描电子显微镜观察传感器表面，对传感器检测响应进行了阳性确认。较高的样品流速（0.5-5.0 mL/min）会产生更高的传感器检测响应。在所有测试的三种水基质中，都能达到检测 10 个/mL 以下的包囊的能力，且在 15 分钟内即可获得显著的传感器响应。我们还展示了在 5.0 mL/min 的高流速下，在 1 升样品中以 1 个/mL 的低浓度进行分析的可行性。
