Biomarkers are biological characteristics that can be observed or measured during disease conditions, and compared to the healthy state. Biomarkers have been used in medical history to study disease progression, to develop drugs, or to predict drug efficacy. However, in complex diseases such as in cancer, biomarkers vary tremendously among patients and disease stages. Cell surface receptors, proteins that are located at the cell surface and deliver external signals into the cell, are a significant group of easily-detectable biomarkers. Along with the detection of particular biomarkers related to a disease, extensive characterization of expression patterns is necessary to optimize their application. Therefore, we designed a technique to imprint or capture the expression pattern of these receptors on silver nanoparticles. We incorporated branched molecules that can simultaneously bind to the target receptors and the nanoparticle surface. To develop the technique, we used melanocortin receptor 1 (MC1R), a receptor present at high levels on the surface of melanoma cells, as a test system. We determined optimum binding of this molecule in an established melanoma cell line, WM-266-4. We also synthesized a labeled molecule that was used to estimate the number of MC1R proteins on these cells. These studies indicate that this might be a promising approach for developing sensitive and cost-effective tools to characterize cell surface receptors in studying complex diseases and cell mechanisms. / MS / Biomarkers are biological characteristics that can be observed or measured during disease conditions, and compared to the healthy state (e.g. grades of fever during infection). Biomarkers have been used in medical history to study disease progression, to develop drugs, or to predict drug efficacy. However, in complex diseases such as in cancer, biomarkers vary tremendously among patients and disease stages. Cell surface receptors, proteins that are located at the cell surface and deliver external signals into the cell, are a significant group of easily-detectable biomarkers. Along with the detection of particular biomarkers related to a disease, extensive characterization of expression patterns is necessary to optimize their application. Therefore, we designed a technique to imprint or capture the expression pattern of these receptors on silver nanoparticles. We incorporated branched molecules that can simultaneously bind to the target receptors and the nanoparticle surface. To develop the technique, we used melanocortin receptor 1 (MC1R), a receptor present at high levels on the surface of melanoma cells, as a test system. We determined optimum binding of this molecule in an established melanoma cell line, WM-266-4. We also synthesized a labeled molecule that was used to estimate the number of MC1R proteins on these cells. These studies indicate that this might be a promising approach for developing sensitive and cost-effective tools to characterize cell surface receptors in studying complex diseases and cell mechanisms.

Neutrophil activation is the most important initial immune defense against invading microbes in newborn infants. The reduced neutrophil migration and uncontrolled regulation of reactive oxygen species (ROS) production observed in neonates, could result in a diminished infectious response or in tissue damage. The aims were to study neutrophil chemotactic response towards IL-8 and fMLP in term neonates; to examine neutrophil receptor expression involved in adhesion, migration, phagocytosis and complement after stimulation with IL-8 and fMLP in term neonates; and to investigate neutrophil production of ROS, induced by PMA and E.coli, after preincubation with IL-8 and fMLP in term and preterm newborn infants. Comparisons were made to neutrophils from healthy adults. Chemotaxis was distinguished from randomly migrating neutrophils, and the neutrophil migration distance and the number of migrating neutrophils per distance was evaluated. Neutrophils were labeled with antibodies to cell surface antigens (CD11b, CD18, CD65, CD15S, CD162, CD44, CD35, CD88, CD181, CD182 and CD64) after stimulation with IL-8 and fMLP. After preincubation of neutrophils with fMLP or IL-8 and stimulation with PMA or E.coli, respiratory burst was detected. The same analyses were also made in preterm infants (median 25+3weeks GA; range 23+0–29+2) within 3 days postnatal age. Neutrophils from neonates exhibited different migratory and receptor responses to IL-8 and fMLP, with a diminished response towards IL-8 in term newborn infants in terms of reduced chemotaxis and modulation of receptors involved in adhesion, chemotaxis, complement and phagocytosis as compared to adults. fMLP reduced PMA- and E.coli-induced respiratory burst in neutrophils from term neonates and adults. The reduced respiratory burst by fMLP may be a mechanism for reducing the detrimental effects of uncontrolled inflammation. Although a similar burst reduction was observed in preterm infants born >25 weeks GA with fMLP, a diminished neutrophil respiratory burst modulation in very preterm infants cannot be excluded and requires further studies at different gestational and postnatal ages.