Nanobiotechnological improvements defined on the utilization of biological materials and principles have enormously partaken to revolutionize physical, chemical, and biological sciences. However, the exploration of plant nanobiotechnology is still in its outset. The search for novel tools to monitor plant biomolecules is an emerging issue for the nanobiotechnologists. Given this, a genetically encoded FRET-based nanobiosensor has been developed to monitor the popular plant cardiac glycoside – digoxin, which is used as the most common prescription drug for heart-related illnesses across the world. Digoxin is sourced from the leaves of the foxglove plant (Digitalis purpurea L.) and has a significant demand in the medical sector. Moreover, with the rising popularity of the herbal formulations in the global market, attention towards the authentication and quality control of the herbal drugs is important. Furthermore, digoxin has a very narrow therapeutic range, i.e., 0.6 nM - 2.6 nM. Therefore, strict monitoring of blood digoxin levels is necessary. Besides, previously used techniques for drug authentication and quantification of small-molecule drugs in blood samples are not the best choice available. The nanobiosensor is based on the FRET (Fluorescence Resonance Energy Transfer) mechanism, and it is constructed in such a way that it gives a changed FRET output in the presence of digoxin. Two fluorophores, enhanced cyan fluorescent protein (ECFP) and Venus, were attached on either end of the sensory domain - human nuclear receptor ROR-gamma (RORγt). The developed nanobiosensor was named as fluorescent indicator protein for digoxin, (FLIP-digoxin). The ligand binding affinity of FLIP-digoxin was calculated as 425 μM. Affinity mutants of the FLIP-digoxin were also generated to measure digoxin in wide concentration ranges. This sensor offers high-throughput qualitative analysis of digoxin in Digitalis preparations procured from local drug stores. It confirms the authenticity of the preparations through the detection of digoxin. The FLIP-1n was also able to monitor digoxin concentration in serum samples in lesser than 5 min. The nanobiosensor was found pH stable, digoxin-specific, non- interfered by the biological serum species and can perform high throughput screening of the Digitalis powder, infusion and tincture preparations.

以生物材料和原理的利用为基础的纳米生物技术改进极大地推动了物理、化学和生物科学的革命。然而，植物纳米生物技术的探索仍处于起步阶段。寻找监测植物生物分子的新工具是纳米生物技术专家面临的一个新兴问题。鉴于此，已经开发出一种基于基因编码的 FRET 纳米生物传感器来监测流行的植物强心苷——地高辛，地高辛被用作世界各地最常见的心脏相关疾病处方药。地高辛来自毛地黄植物 ( Digitalis purpurea)的叶子L.) 并且在医疗领域有很大的需求。此外，随着草药制剂在全球市场的日益普及，对草药的认证和质量控制的关注很重要。此外，地高辛的治疗范围很窄，即 0.6 nM - 2.6 nM。因此，有必要严格监测血液地高辛水平。此外，以前用于血液样本中小分子药物的药物鉴定和定量的技术并不是目前的最佳选择。纳米生物传感器基于 FRET（荧光共振能量转移）机制，其构造方式使得在存在地高辛的情况下会产生变化的 FRET 输出。两种荧光团，增强型青色荧光蛋白 (ECFP) 和 Venus，连接在感觉域的任一端 - 人核受体 ROR-γ（RORγt）。开发的纳米生物传感器被命名为地高辛的荧光指示蛋白（FLIP-地高辛）。FLIP-地高辛的配体结合亲和力计算为425 μM。还产生了 FLIP-地高辛的亲和突变体，以测量宽浓度范围内的地高辛。该传感器可对地高辛进行高通量定性分析从当地药店采购的洋地黄制剂。通过地高辛检测证实制剂的真实性。FLIP-1n 还能够在不到 5 分钟的时间内监测血清样品中的地高辛浓度。发现该纳米生物传感器 pH 稳定、地高辛特异性、不受生物血清种类的干扰，并且可以对洋地黄粉末、输液和酊剂制剂进行高通量筛选。