| Abstract
| - Fluorescent F-actin (red) and clathrin (green) images of cells incubated with BSA−APTMS−SPION for 24 h showing background levels of clathrin similar to that of control cells. A cell response similar to that of control cells is demonstrated with no adverse cell damage and no endocytosis.
- Immobilization of bovine serum albumin (BSA) on surface-modified superparamagneticiron oxide nanoparticles (SPION) has been performed by two different double-step immobilization approaches. The first approach consists of preparation of SPION by controlledchemical coprecipitation in the presence of BSA solution, whereas the second approachincludes preliminary surface modification of SPION with an amine group using a couplingagent of 3-aminepropyltrimethoxysilane (APTMS). Both procedures are followed by 1-ethyl-3-(3-dimethylaminepropyl) carbodiimide hydrochloride (EDC) activation with sequentialimmobilization of the layer of BSA. Additionally, an attempt to modify the surface of SPIONwith amine and carboxylic groups is undertaken by using l-aspartic acid (LAA). TEM showsthat the particle size varies in the range 10−15 nm and does not change significantly afterthe coating process. The presence of BSA and amine groups on the surface of SPION isconfirmed by FT-IR. Magnetic properties are investigated by VSM and results indicate thatthe superparamagnetic properties are retained for BSA-coated SPION while reducing thevalue of saturation magnetization (Ms). The binding capacity is estimated from thermogravimetric and chemical analyses. APTMS-coated SPION show higher BSA binding capacitycompared to that of coprecipitated SPION in the presence of BSA. In vitro tests have beenperformed after the functionalization of SPION with LAA and BSA. Human dermalfibroblasts are incubated with the surface-modified SPION for 6 and 24 h to observe cellbehavior, morphology, cytoskeletal organization, and interactions between cell and SPION.BSA-coated SPION incubated with cells demonstrated a cell response similar to that ofcontrol cells, with no adverse cell damage and no endocytosis, whereas LAA-coated SPIONshow partial endocytosis without cytoskeletal disorganization.
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