Offer no. 29/14

A new bisbithienyl conducting polymer, molecularly imprinted with proteins, particularly with human serum albumin, its preparation and applications

  • Summary:

    A new conducting bisbithiopene polymer molecularly imprinted with human serum albumin (HSA) was fabricated. It was deposited as a few tenth nanometer-tick film on a gold electrode surface by potentiodynamic electropolymerization. The functional monomers used, vis., 2,2'-bithiophen-5-carboxylic acid and p-bis(2,2'-bithien-5-yl)methyl alanine were covalently attached to HSA before the polymerization. The 5,5',5''-tris[(2,2-bithien-5-yl)methane] was used as the crosslinking monomer. This polymer film served as the recognition element in an electrochemical chemosensor for selective detection and/or determination of HSA in urine and blood.

  • Inventors:
    Maciej Cieplak, Katarzyna Szwabińska, Chandra Bikram KC, Paweł Borowicz, Krzysztof Noworyta, Francis D'Souza, Włodzimierz Kutner
  • Advantages / Innovative aspects:
    • Electrochemical sensors used for determination of human serum albumin are attractive alternatives to conventional methods based on colorimetric or fluorescence HSA detrminations.
    • Molecularly imprinted polymers (MIPs) may serve as recognition components of the chemosensors, and they can provide analytical information comparable to that provided by immunosensors, remining free of their drawbacks. The MIP-based chemosensors are more durable, simpler in fabrication, and cheaper than the immunosensors.
    • Electrochemical sensors, including those based on molecularly imprinted polymers, are significantly more sensitive, selective and, moreover, they reveal higher detectability than conventional analytical methods of detection of human serum albumin.
    • The use of semi-covalent imprinting resulted in formation of very well-defined molecular cavities in the polymer ensuring high selectivity of the chemosensor.
    • Detectability of the MIP-HSA chemosensor is sufficient to determine HSA in urine and blood samples.
    • Advantageously, the chemosensor is insensitive to the low molecular-weight inteferences present in the urine and blood samples. Moreover, it is highly selective with respect to three representative proteins accompanying HSA.
  • Keywords:
    chemosensor, moleculary imprinted polymer, semi-covalent imprinting, conducting polymer, electropolymerization, human serum albumin, albuminouria diagnosis, hipoalbuminemia diagnosis, medical diagnosis, medical analysis, analitical chemistry
  • Field:
  • Usage:

    Human serum albumin (HSA) is mainly responsible for transport of several human body inherent important substances and xenobiotics including hormones, fatty acids, and drugs. Moreover, it maintains oncotic pressure and prevents photodegradation of folic acid. A low level of HSA in plasma (hypoalbuminemia) indicates liver failure, cirrhosis, and chronic hepatitis. Moreover, the HSA concentration can serve as an indicator of a coronary heart disease and multiple myeloma. Its moderate concentration, i.e., 30 to 300 ľg/mL, in urea is indicative of microalbuminuria and, at higher concentrations, of albuminuria, both caused by kidney damage, most often resulting from diabetes or hypertension. Therefore, HSA determination is so much important for clinical analysis. Colorimetry is the most commonly used method of HSA determination. It relies on Bromocresol Green binding. However, it suffers from serious disadvantages. Most importantly, the HSA concentration is often overestimated with this method because equilibrium of the HSA reaction with this dye is not reached and, therefore, the analytical signal is time dependent. Apparently, this signal is rising fast all the time during the HSA determination. Moreover, Bromocresol Green may also react with other proteins present. Furthermore, fluorescence spectroscopy, often used for determination of HSA, is generally inadequate with respect to selectivity and stability. This is because fluorescence of other proteins present in biological samples can easily interfere the HSA emission. Only quite recently, the first, based on the Pittsburgh Green II dye, fluorescence protocol of HSA determination was developed affording the time independent response to HSA. Moreover, a label-free impedimetric HSA immunosensor based on silicon nitride was fabricated. However, it revealed disadvantages typical of immunosensors. That is, its fabrication was rather complicated and expensive. Besides, stability of anti-HSA antibodies used was quite limited. Moreover, this immunosensor could operate as a disposable device only because its sensitivity dropped as much as by 40% when HSA was extracted from its recognizing film after the first use. The heiren devised chemosensor allows for fast and selective electrochemical HSA determination without the nesesity of labeling this protein. It is easy to fabricate and, moreover, it is a reusable device. Hence, this chemosensor may find its use in clinical analysis. Moreover, the method of semi-covalent imprinting of HSA developed heiren may be easely extended to produce chemosensors for selective determination of other proteins.

  • State of the progress:
    stage of research
  • Intellectual property rights:
    Patent in Poland
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