Sample preparation from complex matrixes with minute DNA content could highly benefit from the miniaturization of solid phase extraction (SPE) based devices due to an increased surface area-to-volume ratio. However, the adaptation of "bench-top" based protocols for DNA purification to miniaturized devices is not as straightforward as it might seem, and several issues need to be considered. A careful evaluation of DNA extraction and purification protocols needs to be performed, taking into account the complexity of such samples, and in order to facilitate the integration with the subsequent step, normally DNA amplification. In this work a washable and reusable miniaturized device for DNA purification based on microscale solid phase extraction (μSPE), containing a commercial disposable silica membrane as the solid phase for DNA capture, was developed. The DNA purification protocol was firstly optimized by testing a set of different conditions, including buffer composition in all three steps of analysis and incubation during the elution step, with the objective of increasing the DNA yield and facilitating the integration in a miniaturized setting. This protocol was then tested with olive oil samples, including a pretreatment step also developed and optimized in this work. DNA analysis of olive oil samples is of high interest for the detection of fraudulent adulteration with oil from other seeds and for cultivar identification. The results were compared with the commercial NucleoSpin® Food kit regarding efficiency and purity of the DNA extract, by estimating the DNA yield and evaluating the absorbance ratios A260/280 and A260/230. The miniaturized DNA purification device showed better performance than the commercial kit tested, making this method a very promising sample preparation approach for olive oil and other samples with minute DNA content.

中文翻译：

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在可清洗和可重复使用的微型设备上从橄榄油中高效提取和纯化 DNA

由于表面积与体积比的增加，基于固相萃取 (SPE) 的设备的小型化可以极大地受益于 DNA 含量极低的复杂基质的样品制备。然而，将基于“台式”的 DNA 纯化协议应用于小型化设备并不像看起来那么简单，需要考虑几个问题。需要对 DNA 提取和纯化方案进行仔细评估，考虑到此类样品的复杂性，并为了促进与后续步骤的整合，通常是 DNA 扩增。在这项工作中，一种基于微型固相萃取 (μSPE) 的可清洗和可重复使用的小型 DNA 纯化装置，包含商业一次性硅胶膜作为 DNA 捕获的固相，已开发。DNA 纯化方案首先通过测试一组不同的条件进行优化，包括洗脱步骤中所有三个分析和孵育步骤中的缓冲液组成，目的是提高 DNA 产量并促进小型化环境中的整合。然后用橄榄油样品测试该方案，包括在这项工作中开发和优化的预处理步骤。橄榄油样品的 DNA 分析对于检测来自其他种子的油的欺诈性掺假和品种鉴定具有重要意义。通过估计 DNA 产量和评估吸光度比 A260/280 和 A260/230，将结果与商业 NucleoSpin® Food 试剂盒在 DNA 提取物的效率和纯度方面进行比较。