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Ultra-sensitive detection of pharmaceuticals in water

至关重要的人类和动物健康,消耗量大制药物质在水生环境中的生物活性可对生态系统有害的影响无处不在。他们通过灵敏和快速检测方法是一个重大问题。从IPBS-图卢兹(CNRS / UNIVERSITE图卢兹III-保罗沙巴提耶)的一个小组已经表明,其为单个的DNA分子的高通量分析微阵列有效地检测DNA嵌入剂的存在。这项工作,发表在该杂志分析化学,水质的监控,以及活性分子的用于治疗癌症的筛查认定申请。


Medicines could soon enter the list of priority substances for aquatic environments with imposed quality standards. To support this evolution and allow regular monitoring of the quality of surface water in the future, sensitive, rapid, low-cost, transportable and even on-site tools must be developed. Biosensors combining nanotechnologies, for their capacity for miniaturization, with DNA, as a material of choice for biosensing, are promising solutions.

A large number of prescribed drugs exert their activity through their interaction with DNA by intercalation between its base pairs which blocks its transcription or replication. They are thus particularly relevant targets because of the genotoxic and/or cytotoxic risk they can present. The intercalation of a compound in DNA is accompanied by structural changes in the molecule such as an increase in the contour length of the DNA and possibly a change in its rigidity. The biochip developed and used by researchers in Dr. Salomé's team was designed to access such structural modifications in basic research. It consists of nanoparticles attached to the free end of DNA molecules immobilized, by their other end, on anchoring sites isolated and organized in a regular array on a support. Using videomicroscopy and image analysis, the amplitudes of motion of several hundreds of these nanoparticles can be measured in parallel over time. Combined with this Tethered Particle Motion technique, our biochip allows the conformational dynamics of single DNA molecules to be monitored at high speed and the detection of structural changes in DNA with high resolution. In parallel with studies of DNA biophysics, the researchers are exploring the potential of the method as a biosensor. They first demonstrated the feasibility of detecting DNA intercalators by this method by observing a dose-dependent response for fluorescent intercalators whose mechanical effects are established in the literature. Then they demonstrated that the method can be applied to the measurement of the concentration in natural water of doxorubicin, a therapeutic molecule used in the treatment of cancer, over a wide range of concentrations. Thus, the method allows the detection of intercalating agents provided that their interaction with DNA does not notably reduce its rigidity. The processes necessary for its implementation being of low-tech type, environmentally friendly, cost effective and miniaturizable make this method a promising tool for environmental analyzes. Furthermore, this method also finds applications in the field of screening for active molecules interacting with DNA.

Work continues towards the development of solutions for specific detection by integrating recognition molecules into our biochip for environmental but also diagnostic applications.

Scheme of the single DNA molecule biochip: a glass slide wears an array of submicrometric sized sites of anchor protein for immobilization by one end of DNA molecules linked to a nanoparticle by the other end.

Principle of the detection of an intercalator: the increase in effective length of the DNA molecule leads to an increase in the amplitude of motion of the nanoparticle DeltaA which is measured by videomicroscopy and image analysis.

Calibration curve:该信号,即在运动的幅度的变化,与嵌入剂在几个数量级的浓度增加而增加。
© Laurence Salomé

Reference

Single-molecule sensing of DNA intercalating drugs in water

Serres Sandra, Tardin Catherine and Salomé Laurence. Analytical Chemistry.2020 May 31. doi: 10.1021/acs.analchem.0c00184

更多的信息

  • Patent « Biopuces pour l’analyse de la dynamique de molécules d’acide nucléique » Plénat T., Salomé L., Tardin C., Thibault C., Trévisiol E., Vieu C. FR 1057031 déposé le 3/9/2010 ; EP 2 611 940 B1 déposé le 1/9/2011
  • Plénat T.*, Tardin C.*, Rousseau P. and Salomé L. (2012) High-throughput single-molecule analysis of DNA-protein interactions by Tethered Particle Motion Nucleic Acids Res 40(12) e89
  • Guilbaud S., Salomé L., Destainville N., Manghi M., Tardin C (2019) Dependence of DNA persistence length on ionic strength and ion type. Phys Rev Lett 122, 028102

Contacts

Researcher:

Laurence Salomé | Laurence.Salome@ipbs.fr | 05 61 17 59 39
IPBS-Toulouse, CNRS, Université Paul Sabatier
205, route de Narbonne BP 64182 31077 TOULOUSE cedex 4

Press:

Françoise Viala | communication@ipbs.fr | 06 01 26 52 59