Design and Synthesis of Class-specific Haptens for Organophosphorus Insecticides

With more than 10 years of experience in antibody development, Creative Biolabs has specific expertise in the design and synthesis of small molecule haptens. Based on our advanced technology platforms, we provide comprehensive services for the design and synthesis of small molecule haptens and can perform almost any type of chemistry synthesis you need.

Overview of Organophosphorus (OPs)

Insecticides play an important role in improving the quantity and quality of crops. However, due to the widespread use and high toxicity of pesticides, people are increasingly concerned about pesticide residues in food and the environment. OPs insecticides are highly toxic pesticides with broad-spectrum insecticidal activity and relatively low stability. They have been widely reported in food and environmental samples. Therefore, the monitoring of OPs residues is of great significance not only for protecting human health, but also for international trade and regulatory control.

Immunoassay is one of the most promising strategies for detecting OPs. The sensitivity of an immunoassay for low molecular weight compound is related to the quality of the excellent antibodies and antigens. OPs is a low molecular weight compound (hapten) that cannot produce antibodies when used alone. Therefore, it is necessary to design an appropriate hapten to improve the sensitivity of the immunoassay. Chemical synthesis methods can be used to prepare haptens and couple them to carrier proteins for use as candidate compounds. The best antigen is selected by immunoassay and other methods.

Synthesis of Haptens for OPs

The current trend in pesticide immunoassays is the development of class-specific immunoassays or multi-analyte assays in which multiple targets can be measured in one test. An effective strategy for class-specific immunoassays is to design and synthesize generic haptens, and then prepare class-specific antibodies. The synthesis of class-specific haptens is an important step in the development of OPs immunoassay methods. Most OPs share a common structure: O, O-diethyl or O, O-dimethyl phosphorothioate. Based on the common structure of OPs insecticides (O, O-dimethyl phosphorothioate), three haptens with different spacer arms were synthesized. The synthetic pathway of these haptens is shown in Fig.1. Monoclonal antibodies against generic hapten, O, O-diethyl O-(5-carboxy-2 fluorophenyl) phosphorothioate, have been produced for the determination of OPs insecticides in a class-specific manner. These monoclonal antibodies showed desirable characteristics that can be used for class-specific assays, such as broad specificity and high sensitivity.

Chemical structures of haptens for OPs. Fig.1 Chemical structures of haptens for OPs. (Liang, 2008)

Our Service for Haptens Design and Synthesis

In order to develop a class-specific immunoassay method for O, O -dimethyl OPs insecticides, including malathion, dimethoate, phenthoate, phosmet, methidathion, fenitrothion, methyl parathion and fenthion, Creative Biolabs offers dozens of hapten design and chemical synthesis services to generate immunogens capable of producing antibodies. Our haptens are designed according to O, O-dimethyl phosphorothioate as the generic structure of OPs insecticides. We conduct multiple studies to determine the length of the spacer arm (4-carbon and 6-carbon), because the structure of the protein conjugate may be affected by the length of the spacer arm. All compounds are identified by MS, IR and P-NMR and verification of the protein conjugates is measured by the UV-Vis spectrum. For multi-residue detection of OPs insecticides, the design of generic haptens is similar to that used in earlier reports (Fig.2). However, the structure of generic hapten is introduced by a phenyl group, which is beneficial for the production of the antibody.

The chemical structure of the generic haptens. Fig.2 The chemical structure of the generic haptens. (Liu, 2012)

Why Choose Us?

  • Design and optimization of the synthetic route
  • Process research, development and optimization
  • Small - and large-scale synthesis of small molecule haptens
  • Advanced small molecule synthetic and analytical platform
  • Expert project management
  • Cost-effectiveness and high efficiency

If you want to know more, please feel free tocontact us.

References

  1. Liang, Y.; et al. Synthesis of three haptens for the class-specific immunoassay of O, O-dimethyl organophosphorus pesticides and effect of hapten heterology on immunoassay sensitivity. Analytica chimica acta. 2008, 615(2): 174-183.
  2. Liu, B.; et al. Production of the class-specific antibody and development of direct competitive ELISA for multi-residue detection of organophosphorus pesticides. Food and agricultural immunology. 2012, 23(2): 157-168.
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