Design and Synthesis of Haptens for Cadmium

The successful preparation of cadmium haptens is essential for preparing specific antibodies, which are promising analytical tools for rapid and sensitive determination of metal ions in the environment. Creative Biolabs is leading in the field of haptens design and synthesis; we can provide the best-fit cadmium haptens for our customers all over the world.

Contamination of Cadmium

Most heavy metals are classified as persistent pollutants in the environment; among them, cadmium is a toxic environmental element that affects adversely and poses a significant threat to human health. The presence of cadmium in water, air, soil, and food induces a series of environmental problems and exposes human health to potential risks. Depending on the various sources of exposure and ingestion, a high accumulation of cadmium is primarily in the kidneys and ultimately leads to kidney failure. Cadmium exposure can also cause acute damages to the gastrointestinal tract and respiratory tract, and chronically affect the kidney and lung. Cadmium, like other heavy metals that have a biological half-life exceeds 10 years once accumulated in the human body. In addition, low-level chronic exposure of cadmium can contribute to an increased risk of cancer; thus, cadmium has been classified as a carcinogen. Therefore, the immunoassays to rapidly, sensitive, and reliable monitor cadmium residues have attracted extensive attention.

Cadmium-chelate Complexes as Haptens

Immunoassays need the development of high-affinity antibodies against cadmium, which involve the preparation and identification of applicable cadmium haptens. Cadmium cannot induce immunoreactions directly because of their low molecular weight. Therefore, cadmium should be combined with bifunctional chelators to form cadmium-chelator complexes and be used as haptens, and then they are coupled to carrier proteins to prepare immunogenic antigens. For example, the cadmium-ethylene diamine tetraacetic acid (EDTA) complex have been produced in previous studies, which is the first essential step for preparing antibodies against cadmium ions. Based on the production of antibodies against cadmium, sensitive, and accurate immunoassays for quantitative detection of cadmium have been successfully established.

Molecular structure of metal-chelator-protein complex. Fig.1 Molecular structure of metal-chelator-protein complex. (Xi, 2012)

Design and Synthesis of Haptens for Cadmium

The key to immunoassay development is based on the successful preparation of specific antibodies against the cadmium pollutants. The design and synthesis of suitable and high-quality cadmium haptens are the prerequisites for the detection of cadmium with low detection limits and a full working range. Cadmium, like most other simple metal ions, is too small to elicit an immune response of their low molecular weight. However, under appropriate conditions, such as metal-chelator complexes, which can be used as haptens, are made immunogenic by coupling to carrier proteins to increase the likelihood of inducing specific antibody responses.

Cadmium-chelator complexes are immunogenic and could elicit an immune response, and high molecular weight immunogens are constructed using bifunctional chelators. Creative Biolabs offers many standard kinds of chelators or bifunctional chelators for the preparation of antigens for heavy metal ions, such as EDTA, amino benzyl-EDTA, ITCBE, DOTA, and their derivatives. Then the metal-chelator complexes are covalently conjugated to carrier proteins, containing keyhole limpet hemocyanin (KLH), bovine serum albumin (BSA), and ovalbumin (OVA). Creative Biolabs can further characterize the quality and stability of antigens by several commonly used techniques, including ultraviolet spectrometry, Fourier transform infrared spectroscopy (FT-IR), SDS–PAGE electrophoresis, and graphite furnace atomic absorption spectrometry.

The main factors affecting antibody production are the structure of the cadmium-chelator complexes. Based on the advanced hapten design platform, Creative Biolabs offers the design and synthesis of haptens for cadmium service for our global customers. If you are interested in our service, please feel free to contact us for more details.


  1. Xi, T.; et al. Preparation and characterization of artificial antigens for cadmium and lead. Biological trace element research. 2012, 150(1-3): 411-417.
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