Molecular Imprinting Technique for Specific Protein Recognition
The research field of diagnostic systems focuses on the development of novel, innovative substrates with specific protein recognition structures for use in proteomic separation, identification and characterization. Various substrates with different chemical and mechanical properties are suitable as carrier materials for protein detection. The specific information for protein recognition can be transferred into the substrates using molecular imprinting techniques.
The focus of this research is the development, preparation and characterization of a tailored hydrogel matrix for different model proteins. Polyacrylamide gels (PAG) and gels made of polyethylene glycol-acrylamide copolymers (PEGA) and N, N'-methylenebisacrylamide, for instance, can also be modified by acrylate-functionalized hyaluronic acids, dextrans and alginates and used as a protein capture matrix. Modular protein biochips, for use in different diagnostic methods, can be built from these photo-chemically crosslinkable layers.
Another research focus is the development and characterization of molecularly imprinted hydrogel beads as a capture matrix for specific protein recognition. Already, hydrogel nanoparticles are of great practical relevance for diagnostic methods based on protein-protein interactions. The current standard method in clinical diagnostics for the quantitative determination of the blood sugar value in diabetes treatment is carried out on the basis of a particle-based assay, for example. Here, the aim is to develop molecularly shaped capture beads that could later be used in diagnostic procedures, such as an immuno-turbidimetric assay to determine the HbA1c value.
A third research focus is on molecularly shaped Ormocer/Sol gels as a capture matrix in affinity chromatography. Affinity chromatography is one of the most powerful biotechnological separation methods. It is based on the specific recognition of a protein by an antibody or, in the case of enzymes, on the specific affinity of an enzyme to its substrate, an inhibitor or a co-factor. It is already used today to isolate analytes from solutions or mixtures of different substances. The hormone Pregnant Mare Serum Gonadotropin (PMSG), for example, which is found in the blood serum of pregnant mares, is purified and isolated by affinity chromatography. However, the columns which are commonly used are relatively expensive and can only be used in a limited number of cycles. Molecularly shaped Ormocer/Sol gels would be more stable against external influences and would enable a high number of cycles without loss of affinity when reused. Molecular imprinting of larger biomolecules, especially proteins, leads to a significant improvement in existing biotechnological processes. It also establishes new possibilities in biotechnology with regard to effective isolation and cleaning of highly active components and new drugs.
A diagnostic system for the early detection of peri-implantitis inflammation of dental implants has been developed and integrated into a chewing gum. This was a result of an EU-funded project ("STEP", FP7-SME, project no.: 314911) with 7 cooperating partners from 4 European countries.
Inflammatory processes in the oral cavity are often recognized too late and, therefore, may cause the loss of the implant. Responding to inflammation, the body's immune system activates enzymes (MMPs, matrix metalloproteinases) which are responsible for the progressive destruction of tissue.
The chewing gum test, which we have developed, is based on the recognition of these MMPs by a sensitive peptide. The peptide chain contains a carrier molecule with Donatonium, which is cleaved and released by the enzyme. Donatonium has a very bitter taste, which is immediately felt when the chewing gum is chewed. For the coupling of the denatonium to the sensitive peptide, the bitter substance was modified by the introduction of a carboxyl group without the bitter taste being lost. When the patient feels a bitter taste while chewing the gum coupled with the detection system, this is an alarm signal for him to visit a dentist as soon as possible. The principle of using the tongue as a constantly available detector can also be applied to early detection of other diseases in oral cavities.
