In vitro utilization of ferromagnetic nanoparticles in hemodialysis therapy

Abstract

The in vitro utilization of biocompatible ferromagnetic nanoparticles (BFNs) inhemodialysis (HD), routinely used today for the treatment of end stage renal disease(ESRD), is introduced in this work. The proposed strategy is termed magnetically assistedhemodialysis (MAHD) and it aims to become a more efficient development ofconventional HD. The method is based on the production of biocompatible ferromagneticnanoparticles–targeted binding substances conjugates (BFNs–TBSs Cs) constructed ofBFNs and specifically designed TBSs that should have high affinity and binding capacityfor target toxic substances (TTSs) which must be removed from the ESRD patientsubjected to HD. Antibodies or even specific proteins could serve as the TBS ofthe desired BFNs–TBSs Cs. The BFNs–TBSs Cs should be administered to thepatient timely prior to the MAHD session so as to bind with the desired TTSsduring their free circulation in the vascular network. Eventually, the completeBFNs–TBSs–TTSs structure can be selectively removed during the MAHD session bymeans of an external inhomogeneous magnetic field that is applied either at thedialyzer or at other collection point(s) along the blood circulation line of the dialysismachine. The advantages of MAHD over conventional HD regarding the patient’scomfort and overall health status are discussed in detail among practical issues.To examine this proposition we employedFe3O4 and bovine serum albumin (BSA) as the BFN and the TBS constituents respectively, sincethey are both highly biocompatible. By means of x-ray diffraction, atomic forcemicroscopy, circular dichroism spectropolarimetry, UV–vis spectrophotometry,SQUID magnetometry, and nuclear magnetic resonance we evaluated (i) thestructural/morphological characteristics, (ii) the magnetic retraction efficiency,and most importantly (iii) the toxin binding affinity and capacity of both bareFe3O4 BFNsand Fe3O4–BSA Cs by performing in vitro experiments on specific TTSs. Homocysteine and p-cresolwere chosen as representative TTSs and were investigated in great detail. Theresults obtained prove the in vitro applicability of the proposed MAHD method.Corrections were made to this article on 6 November 2007 (see figure 10 caption and lines 10 and 11 of page 11). The corrected electronic version is identical to the print version.