Preparation, characterization, and binding profile of molecularly imprinted hydrogels for the peptide hepcidin

Surface plasmon resonance based on molecularly imprinted nanoparticles for the picomolar detection of the iron regulating hormone Hepcidin-25

BACKGROUND

Molecularly imprinted polymer (MIP) technique is a powerful mean to produce tailor made synthetic recognition sites. Here precipitation polymerization was exploited to produce a library of MIP nanoparticles (NPs) targeting the N terminus of the hormone Hepcidin-25, whose serum levels correlate with iron dis-metabolisms and doping. Biotinylated MIP NPs were immobilized to NeutrAvidin™ SPR sensor chip. The response of the MIP NP sensor to Hepcidin-25 was studied.

FINDINGS

Morphological analysis showed MIP NPs of 20-50 nm; MIP NP exhibited high affinity and selectivity for the target analyte: low nanomolar Kds for the interaction NP/Hepcidin-25, but none for the NP/non regulative Hepcidin-20. The MIP NP were integrated as recognition element in SPR allowing the detection of Hepcidin-25 in 3 min. Linearity was observed with the logarithm of Hepcidin-25 concentration in the range 7.2-720 pM. LOD was 5 pM. The response for Hepcidin-20 was limited. Hepcidin-25 determination in real serum samples spiked with known analyte concentrations was also attempted.

CONCLUSION

The integration of MIP NP to SPR allowed the determination of Hepcidin-25 at picomolar concentrations in short times outperforming the actual state of art. Optimization is still needed for real sample measurements in view of future clinical applications.

Molecular imprinting science and technology: a survey of the literature for the years 2004-2011

Herein, we present a survey of the literature covering the development of molecular imprinting science and technology over the years 2004-2011. In total, 3779 references to the original papers, reviews, edited volumes and monographs from this period are included, along with recently identified uncited materials from prior to 2004, which were omitted in the first instalment of this series covering the years 1930-2003. In the presentation of the assembled references, a section presenting reviews and monographs covering the area is followed by sections describing fundamental aspects of molecular imprinting including the development of novel polymer formats. Thereafter, literature describing efforts to apply these polymeric materials to a range of application areas is presented. Current trends and areas of rapid development are discussed.

Functional characterization of fluorescent hepcidin

Hepcidin is a peptide hormone that regulates homeostasis in iron metabolism. It binds to the sole known cellular iron exporter ferroportin (Fpn), triggers its internalization, and thereby modulates the efflux of iron from cells. This functional property has been adopted in this study to assess the bioactivity and potency of a range of novel fluorescent hepcidin analogues. Hepcidin was selectively labeled with 6-carboxyfluorescein (CF) and 6-carboxytetramethylrhodamine (TMR) using Fmoc solid phase peptide chemistry. Internalization of Fpn by hepcidin was assessed by high-content microscopic analysis. Both K18- and M21K-labeled hepcidin with TMR and CF exhibited measurable potency when tested in cultured MDCK and T47D cells expressing human ferroportin. The bioactivity of the labeled hepcidin varies with the type of fluorophore and site of attachment of the fluorophores on the hepcidin molecule.

Molecularly imprinted polymers in drug delivery: state of art and future perspectives

INTRODUCTION

Molecularly imprinted polymers (MIPs) are synthetic receptors, characterized by a high selectivity for the selected template. Among the different applications of MIPs, their use as controlled/sustained drug delivery devices has been extensively explored, even though the optimization of such devices needs to be performed before they are applied in clinical practice.

AREAS COVERED

Within drug delivery, one of the most promising fields is the possibility to modulate the drug release profile in response to a specific external stimulus; MIPs represent potentially suitable vehicles, because of the possibility to insert a stimuli-responsive co-monomer in their structure. This review discusses recent advances in the use of external stimuli to modulate drug release, as well as the synthetic strategies devoted to increase the water compatibility of these systems, which is a base requirement for their application in biomedicine.

EXPERT OPINION

Although it is easy to imagine imprinted polymers for biomedical applications, several aspects have to be further investigated, such as the in vivo studies, efficiency and biocompatibility. However, we think that in the next few years it will possible to see unprecedented progress in the preparation of such systems and the translational application of these intelligent structures in medicine.