Lonini Luca, Accoto Dino, Petroni Silvia, Guglielmelli Eugenio
University Campus Bio-Medico, Via Longoni 83 00155 Rome, Italy.
J Biochem Biophys Methods. 2008 Apr 24;70(6):1180-4. doi: 10.1016/j.jbbm.2007.05.003. Epub 2007 May 23.
The rapid and precise delivery of small volumes of bio-fluids (from picoliters to nanoliters) is a key feature of modern bioanalytical assays. Commercial ink-jet printers are low-cost systems which enable the dispensing of tiny droplets at a rate which may exceed 10(4) Hz per nozzle. Currently, the main ejection technologies are piezoelectric and bubble-jet. We adapted two commercial printers, respectively a piezoelectric and a bubble-jet one, for the deposition of immunoglobulins into an ELISA plate. The objective was to perform a comparative evaluation of the two classes of ink-jet technologies in terms of required hardware modifications and possible damage on the dispensed molecules. The hardware of the two printers was modified to dispense an enzyme conjugate solution, containing polyclonal rabbit anti-human IgG labelled with HRP in 7 wells of an ELISA plate. Moreover, the ELISA assay was used to assess the functional activity of the biomolecules after ejection. ELISA is a common and well-assessed technique to detect the presence of particular antigens or antibodies in a sample. We employed an ELISA diagnostic kit for the qualitative screening of anti-ENA antibodies to verify the ability of the dispensed immunoglobulins to bind the primary antibodies in the wells. Experimental tests showed that the dispensing of immunoglobulins using the piezoelectric printer does not cause any detectable difference on the outcome of the ELISA test if compared to manual dispensing using micropipettes. On the contrary, the thermal printhead was not able to reliably dispense the bio-fluid, which may mean that a surfactant is required to modify the wetting properties of the liquid.
精确快速地输送小体积生物流体（从皮升至纳升）是现代生物分析检测的一项关键特性。商用喷墨打印机是低成本系统，能够以每个喷嘴可能超过10⁴赫兹的速率喷出微小液滴。目前，主要的喷射技术是压电式和气泡式。我们对两台商用打印机（一台压电式和一台气泡式）进行了改装，用于将免疫球蛋白沉积到酶联免疫吸附测定（ELISA）板中。目的是就所需的硬件改装以及对喷出分子可能造成的损害，对这两类喷墨技术进行比较评估。对两台打印机的硬件进行了改装，以便在ELISA板的7个孔中喷出含有用辣根过氧化物酶（HRP）标记的兔抗人IgG多克隆抗体的酶结合物溶液。此外，ELISA检测用于评估喷出后生物分子的功能活性。ELISA是一种用于检测样品中特定抗原或抗体存在的常用且经过充分评估的技术。我们使用ELISA诊断试剂盒对抗可提取核抗原（ENA）抗体进行定性筛查，以验证喷出的免疫球蛋白与孔中一抗结合的能力。实验测试表明，与使用微量移液器手动加样相比，使用压电式打印机喷出免疫球蛋白不会对ELISA检测结果造成任何可检测到的差异。相反，热敏打印头无法可靠地喷出生物流体，这可能意味着需要一种表面活性剂来改变液体的润湿性。
