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. Author manuscript; available in PMC: 2019 Jul 1.
Published in final edited form as: J Colloid Interface Sci. 2018 Feb 20;521:261–279. doi: 10.1016/j.jcis.2018.02.053

Figure 15.

Figure 15

Optimization of material for a heparin-responsive catheter. (A) Methylene blue in agarose was not stable with more than 40% methylene blue release in PBS after 40 min. The addition of nanoparticles for an integration reduced this release to less than 10%. (B) Photoacoustic images of methylene blue loaded on as-made silica nanoparticles (SSNP; βˆ’23 mV) and methylene blue loaded on thiol-coated silica nanoparticles (SSNP-SH; βˆ’15 mV). Both were treated with PBS and heparin (Hep) but only the thiol-coated nanoparticles were responsive to heparin. The lower ΞΆ-potential facilitated the photoacoustic signal increase. (C) Methylene blue-loaded SSNP-SH treated with heparin offers significantly more signal than SSNP-SH treated with PBS or SSNP. (D) The nanoparticle/agar material was treated with PBS or 10 U/mL heparin and imaged at 680 nm for 9 min with no decrease in signal. Reproduced with permission from Ref32. Copyright (2016) American Chemical Society.