Department of Pharmaceutical Chemistry, H. R. Patel Institute of Pharmaceutical Education and Research, Shirpur 425405, Maharashtra, India.
ACS Biomater Sci Eng. 2022 Feb 14;8(2):470-483. doi: 10.1021/acsbiomaterials.1c01087. Epub 2021 Dec 30.
The diagnosis of tumor biomarkers is an attentive approach for the early detection and treatment of cancer. However, a cost-effective, simple, rapid, selective, and sensitive method is a basic prerequisite for diagnostic research. Herein, we present a novel fluorescence-based label-free sensing strategy for the sensitive and selective detection of carcinoembryonic antigen (CEA) using poly-l-lysine (PLL)-functionalized graphene quantum dots (GQDs). The GQDs were synthesized using a greener method by employing carbonized peanut shell (PNS) waste as a carbon source, and functionalization was accomplished using PLL (PLL-GQDs). The fluorescence stability of the PLL-GQDs was tested in a variety of solvent systems and pH solutions. When compared to nonfunctionalized GQDs (PNS-GQDs), prepared PLL-GQDs demonstrated increased fluorescence lifetime, high quantum yield, excellent photostability, biocompatibility, and greater cellular uptake. The PLL-GQDs with abundant surface amine and carboxylic groups showed selective interactions with an activated CEA antibody (CEA-Ab), resulting in the quenching of fluorescence signals. Because of the strong bioaffinity of CEA to the CEA-Ab, the antibody was unwrapped, resulting in the formation of an antibody-antigen complex and the recovery of fluorescence. As a result of this relationship, a turn "on-off-on" sensing mechanism with a strong response to CEA concentration (0.01 ng mL to 100 μg mL) and a detection limit of 1.19 pg mL was demonstrated. Furthermore, the fabricated CEA immunosensor (CEA-Ab@PLL-GQDs) performed admirably in real sample analysis, with an average recovery of 98.32%. The cellular uptake performance of PLL-GQDs was also demonstrated in the A427 cell lines, exhibiting a greater cellular uptake potential than PNS-GQDs. The cellular bioimaging study demonstrates that PLL-GQDs can be used for additional therapeutic and biological applications.
肿瘤标志物的诊断是癌症早期检测和治疗的一种细致方法。然而，一种具有成本效益、简单、快速、选择性和敏感性的方法是诊断研究的基本前提。在这里，我们提出了一种使用聚赖氨酸（PLL）功能化石墨烯量子点（GQDs）的新型基于荧光的无标记传感策略，用于灵敏和选择性地检测癌胚抗原（CEA）。GQDs 通过使用碳化花生壳（PNS）废物作为碳源的更环保方法合成，并使用 PLL（PLL-GQDs）进行功能化。在各种溶剂系统和 pH 溶液中测试了 PLL-GQDs 的荧光稳定性。与未功能化的 GQDs（PNS-GQDs）相比，制备的 PLL-GQDs 表现出增加的荧光寿命、高量子产率、优异的光稳定性、生物相容性和更高的细胞摄取率。具有丰富表面胺和羧酸基团的 PLL-GQDs 与激活的 CEA 抗体（CEA-Ab）表现出选择性相互作用，导致荧光信号猝灭。由于 CEA 与 CEA-Ab 之间具有很强的生物亲和力，抗体被解开，导致形成抗体-抗原复合物并恢复荧光。由于这种关系，展示了一种对 CEA 浓度（0.01 ng mL 至 100 μg mL）具有强响应且检测限为 1.19 pg mL 的“开-关-开”传感机制。此外，所构建的 CEA 免疫传感器（CEA-Ab@PLL-GQDs）在实际样品分析中表现出色，平均回收率为 98.32%。还在 A427 细胞系中证明了 PLL-GQDs 的细胞摄取性能，表现出比 PNS-GQDs 更高的细胞摄取潜力。细胞生物成像研究表明，PLL-GQDs 可用于额外的治疗和生物应用。
