van der Maaden, Koen published the artcileFluorescent Nanoparticle Adhesion Assay: a Novel Method for Surface pKa Determination of Self-Assembled Monolayers on Silicon Surfaces, Related Products of chlorides-buliding-blocks, the publication is Langmuir (2012), 28(7), 3403-3411, database is CAplus and MEDLINE.
Since the computer industry enables one to generate smaller and smaller structures, silicon surface chem. is becoming increasingly important for (bio-)anal. and biol. applications. For controlling the binding of charged biomacromols. such as DNA and proteins on modified silicon surfaces, the surface pKa is an important factor. Here the authors present a fluorescent nanoparticle adhesion assay as a novel method to determine the surface pKa of silicon surfaces modified with weak acids or bases. This method is based upon electrostatic interactions between the modified silicon surface and fluorescent nanoparticles with an opposite charge. Silicon slides were modified with 3-aminopropyltriethoxysilane (APTES) and were further derivatized with succinic anhydride. Layer thickness of these surfaces was determined by ellipsometry. After incubating the surfaces with an amine-reactive fluorescent dye, fluorescence microscopy revealed that the silicon surfaces were successfully modified with amine- and carboxyl-groups. Two surface pKa values were found for APTES surfaces by the fluorescent nanoparticle adhesion assay. The 1st surface pKa (6.55 ± 0.73) was comparable with the surface pKa obtained by contact angle titration (7.3 ± 0.8), and the 2nd surface pKa (9.94 ± 0.19) was only found by using the fluorescent nanoparticle adhesion assay. The surface pKa of the carboxyl-modified surface by the fluorescent nanoparticle adhesion assay (4.37 ± 0.59) did not significantly differ from that found by contact angle titration (5.7 ± 1.4). In conclusion, the authors have developed a novel method to determine the surface pKa of modified silicon surfaces: the fluorescent nanoparticle adhesion assay. This method may provide a useful tool for designing pH-dependent electrostatic protein and particle binding/release and to design surfaces with a pH-dependent surface charge for (bio-)anal. lab-on-a-chip devices or drug delivery purposes.
Langmuir published new progress about 6249-56-5. 6249-56-5 belongs to chlorides-buliding-blocks, auxiliary class Phase Transfer Catalyst,Inhibitor,Natural product, name is 3-Carboxy-N,N,N-trimethylpropan-1-aminium chloride, and the molecular formula is C23H28N2O4, Related Products of chlorides-buliding-blocks.
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