An electrokinetic study on a synthetic adsorbent of crystalline calcium silicate hydrate and its mechanism of endotoxin removal

ATR-FTIR study of lipopolysaccharides at mineral surfaces

“…Under these conditions LPS aggregate stability is apparently decreased by Ca 2+ binding to PO 4 − in the lipid A region. This is in agreement with previously published studies on rough LPS [9,24,53]. We postulate that Na-LPS aggregates interact with the ZnSe IRE, whereas Ca-LPS aggregate disruption results in LPS monomer interaction via hydrophobic mechanisms.…”

“…These results suggested that Ca 2+ ion bonding to LPS phosphate groups in the lipid A region resulted in disruption of LPS aggregates. Our data support the hypothesis of Wang et al that Ca 2+ may disrupt LPS aggregates causing reorientation on calcium silicate hydrate surfaces [9]. Therefore, the objective of this work was to examine the LPS aggregation and reorientation in the presence of surfaces with varying surface chemistry.…”

“…Additionally, LPS interaction with Ca 2+ results in aggregate reorientation and increased retention on all surfaces studied. LPS aggregates in NaCl solutions are stabilized via H-bonding between saccharide groups [23], whereas the formation of Ca-phosphate bonds in the lipid A region induce aggregate disruption [9] and favor reorientation on a solid surface. These effects are consistent with our previous findings, where Ca-LPS aggregates reoriented on a ZnSe IRE [11].…”

“…4. ATR-FTIR spectra of ser 10 LPS on GeO 2 as a function of pH (3,6,9) in (a) 10 mmol L −1 NaCl and (b) 10 mmol L −1 CaCl 2 . Decreased peak intensity with increased pH was observed, therefore the Y-axis scale is expanded to show spectra details (non-common scale).…”

“…Using attenuated total reflectance ATR-FTIR spectroscopy we probed the behavior of LPS in Na + (Na-LPS) and Ca 2+ (Ca-LPS) solutions (I = 10 mmol L −1 , pH 3,6,9) in contact with ZnSe, GeO 2 , ␣-Fe 2 O 3 , and ␣-Al 2 O 3 surfaces. These surfaces exhibit a range in surface functional group composition, surface charge properties and hydrophobicity (Table 1).…”