Biomedical Engineering Reference
In-Depth Information
of mesoporous carbon in adsorption of small hydrophobic biomolecule was similarly observed for
vitamin E (tocopherol) adsorption, as reported by Vinu et al. [86,87].
The interaction between mesoporous materials and small biomaterials has been utilized for
various purposes. Yang and coworkers used mesoporous silica SBA-15 modifi ed with a hydrophobic
g roup (oct adecyl cha in) as a st ationa r y phase in h igh-per for ma nce l liquid ch romatog raphy ( H PLC) for
the separation of biomolecules [88]. Small biomolecules such as cysteine, glutathione, 6-thiopurine,
and dopamine were successfully separated with better resolution than that observed for a commercial
column under the same condition. Vallet-Regi and coworkers reported the entrapment and release
of ibuprofen, an anti-infl ammatory drug using mesoporous silica MCM-41 supports [89]. When the
drug-loaded MCM-41 was immersed in a simulated body fl uid, ibuprofen was released from the
MCM-41 supports. Stimuli-activated DDS function was reported by Fujiwara and coworkers who
prepared MCM-41 functionalized by a photoactive coumarin derivative that is known to reversibly
dimerize upon photoirradiation [90,91]. Irradiation by UV light (
310 nm) dimerized the coumarin,
enabling it to stably store the guest cholestane. The dimerized coumarin was effi ciently cleaved upon
irradiation by another UV light at around 250 nm, and the trapped coumarin was released.
Supramolecular assemblies of small biomolecules are sometimes expected to express high
functions seen in large biopolymers. For example, well-designed assemblies of amino acids and
peptides can be regarded as a protein mimic. Therefore, preparation of nanohybrids of peptide
assemblies and mesoporous materials would lead to fabrication of protein mimic with a rigid
inorganic framework. According to this concept, the mesoporous materials confi ning the pep-
tide segments in a highly organized mesopore nanospace were developed by Ariga and coworkers
and were named as Proteosilica (Figure 12.13A) [92,93]. Amphiphilic peptides, which have polar
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FIGURE 12.13
(A) Conceptual illustration of Proteosilica. (B) HRTEM image of Proteosilica fi lm: (a) low
magnifi cation and (b) high magnifi cation.
