Applied Phycology and Biotechnology Division, CSIR - Central Salt and Marine Chemicals Research Institute, Gijubhai Badheka Marg, Bhavnagar 364002, Gujarat, India; Academy of Scientific and Innovative Research (AcSIR), Ghaziabad 201002, Uttar Pradesh, India.
Inorganic Materials and Catalysis Division, CSIR - Central Salt and Marine Chemicals Research Institute, Gijubhai Badheka Marg, Bhavnagar 364002, Gujarat, India; Academy of Scientific and Innovative Research (AcSIR), Ghaziabad 201002, Uttar Pradesh, India.
Int J Biol Macromol. 2021 Aug 31;185:644-653. doi: 10.1016/j.ijbiomac.2021.06.201. Epub 2021 Jul 2.
Highly specific graphene-DNA interactions have been at the forefront of graphene-based sensor design for various analytes, including DNA itself. However, in addition to its detection, DNA also needs to be characterized according to its size and concentration in a sample, which is an additional analytical step. Designing a highly sensitive and selective DNA sensing and characterization platform is, thus, of great interest. The present study demonstrates that a bio-derived, naturally fluorescent protein C-phycoerythrin (CPE) - graphene oxide (GO) bio-composite can be used to detect dsDNA in nanomolar quantities efficiently via fluorescent "turn off/on" mechanism. Interaction with GO temporarily quenches CPE fluorescence in a dose-dependent manner. Analytical characterization indicates an indirect charge transfer with a corresponding loss of crystalline GO structure. The fluorescence is regained with the addition of DNA, while other biomolecules do not pose any hinderance in the detection process. The extent of regain is DNA length dependent, and the corresponding calibration curve successfully quantifies the size of an unknown DNA. The incubation time for detection is ~3-5 min. The bio-composite platform also works successfully in a complex biomolecule matrix and cell lysate. However, the presence of serum albumin poses a hinderance in the serum sample. Particle size analysis proves that CPE displacement from GO surface by the incoming DNA is the reason for the 'turn on' response, and that the sensing process is exclusive to dsDNA. This new platform could be an exciting and rapid DNA sensing and characterization tool.
高度特异的石墨烯-DNA 相互作用一直是基于石墨烯的各种分析物传感器设计的前沿，包括 DNA 本身。然而，除了检测之外，还需要根据其大小和在样品中的浓度对 DNA 进行特征描述，这是一个额外的分析步骤。因此，设计一个高灵敏度和选择性的 DNA 传感和特征描述平台非常重要。本研究表明，生物衍生的天然荧光蛋白藻红蛋白（CPE）-氧化石墨烯（GO）生物复合材料可通过荧光“关闭/打开”机制有效地检测纳摩尔数量的 dsDNA。与 GO 的相互作用以剂量依赖性方式暂时猝灭 CPE 荧光。分析特性表明存在间接电荷转移，相应地丧失了结晶 GO 结构。加入 DNA 后荧光恢复，而其他生物分子在检测过程中不会造成任何阻碍。恢复的程度与 DNA 长度有关，相应的校准曲线成功地定量了未知 DNA 的大小。检测的孵育时间约为 3-5 分钟。该生物复合材料平台在复杂的生物分子基质和细胞裂解物中也能成功工作。然而，血清白蛋白的存在对血清样本构成了阻碍。颗粒大小分析证明，进入的 DNA 将 CPE 从 GO 表面置换是“打开”响应的原因，并且传感过程是 dsDNA 特有的。这个新平台可能是一个令人兴奋和快速的 DNA 传感和特征描述工具。
