This article describes mild methods to directly assemble, functionalize, and pattern monolayers of undecylenic acid on hydrogen-terminated Si(111). These monolayers were assembled under very mild conditions from a neat solution of undecylenic acid containing 0.1 mol % 4-(decanoate)-2,2,6,6-tetramethylpiperidinooxy at room temperature without the need for UV light. Because of these mild conditions, monolayers exposing carboxylic acids could be assembled in one step without the need to protect the acid prior to its assembly. The monolayers were extensively characterized by horizontal attenuated total reflection infrared spectroscopy, X-ray photoelectron spectroscopy (XPS), and contact angle goniometry. The monolayers bonded to the silicon surface preferentially through the olefin with no detectable bonds between the carboxylic acids and silicon. The crystallinity of the monolayer was studied by infrared spectroscopy through the antisymmetric--v(a)(CH(2))--and symmetric--v(s)(CH(2))--stretches for methylene. Because it is important for future applications to assemble functional surfaces, methods to react the acid-terminated monolayers with trifluoroacetic anhydride and triethylamine to yield a symmetric anhydride on the monolayer were studied. These anhydrides were reacted with a variety of milligram-quantity amines to yield amide-terminated surfaces. This method was general, and a variety of amines could be bonded to the monolayer. The stabilities of these monolayers upon exposure to ambient conditions and under a variety of solvents were described. Because patterned monolayers have found wide applications, we have developed methods to pattern 1-octadecylamine and poly(ethylenimine) on the micrometer scale using soft lithography. In addition, polymer brushes of polynorbornene with thicknesses from 32 to 150 nm were grown from monolayers patterned with the Grubbs' catalyst. The patterned surfaces were imaged by scanning electron microscopy, scanning probe microscopy, and ellipsometry to determine the thicknesses of the patterns and the fidelity of the method.
Objective To investigate the levels of matrix metalloproteinases (MMPs), myeloperoxidase (MPO) and tissue inhibitor of metalloproteinase-1 (TIMP-1) in tears of patients with Stevens-Johnson syndrome (SJS) and ocular cicatricial pemphigoid (OCP). Design Prospective non-interventional cohort study. Participants Four SJS patients (7 eyes), 19 OCP patients (37 eyes) and 20 post-phacoemulsification healthy controls (40 eyes). Methods Tear washes were collected from all patients and were analyzed for levels of MMP-2, -3, -7, -8, -9, -12, MPO and TIMP-1 using multi-analyte bead-based enzyme-linked immunosorbent assays (ELISA). Total MMP activity was determined using a fluorimetric assay. Correlation studies were performed between the various analytes within study groups. Main Outcome Measures Levels of MMP-2, -3, -7, -8, -9, -12, MPO and TIMP-1 (in ng/µg protein), total MMP activity (in relative fluorescent units/min/µg protein) in tears, MMP-8/TIMP-1, MMP-9/TIMP-1 ratios and the correlations between MMP-8 and MMP-9 and each MMP and MPO. Results MMP-8, MMP-9 and MPO levels were significantly elevated in SJS and OCP tears (SJS > OCP) when compared to controls. MMP activity was highest in SJS while OCP and controls showed lower and similar activities. TIMP-1 levels were decreased in SJS and OCP when compared to controls with OCP levels reaching significance. MMP-8/TIMP-1 and MMP-9/TIMP-1 ratios were markedly elevated in SJS and OCP tears (SJS > OCP) when compared to controls. Across all study groups, MMP-9 levels correlated strongly with MMP-8 and MPO levels and MMP-8 correlated with MPO but did not reach significance in SJS. There was no relationship between MMP-7 and MPO. Conclusions Since MMP-8 and MPO are produced by inflammatory cells, particularly neutrophils, the correlation data indicate that they may be the common source of elevated enzymes including MMP-9 in SJS and OCP tears. Elevated MMP/TIMP ratios and MMP activity suggest an imbalance in tear MMP regulation that may explain the predisposition of these patients to develop corneal melting and chronic complications associated with persistent inflammation. MPO in tears may be a sensitive and specific marker for the quantification of ocular inflammation.
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