multiple stimuli responsiveness types. To overcome biological barriers for in vivo
drug delivery, sophisticated drug carrier is often desired, which could show complex
stimuli responsiveness. Therefore, supramolecular vesicles might be useful DDSs to
achieve specific targeted delivery purposes.
Microfluidic method is of great importance for particle fabrication and sensing.
Host-guest interaction may become a useful protocol to “cross-link” microparticles
in a supramolecular manner for microfluidic fabrication. Zhang et al. reported
one-step fabrication of supramolecular microcapsules from microfluidic droplets
based on CB[8]-ternary complexation [31]. Naphthalene-modified polymer, methyl
viologen-modified AuNP, and CB[8] were processed by microfluidic fabrication. CB
[8] would instantly form ternary complex with naphthalene and methyl viologen to
form highly uniform microcapsules. These microcapsules were characterized with
various techniques. Hydrophobic and hydrophilic cargos could be encapsulated in
the microcapsule wall and cavity, respectively. Surface-enhanced Raman spectroscopy (SERS) was used to characterize AuNP encapsulated inside microcapsules. To
prepare microparticles or nanoparticles with highly uniform composition, size, and
good reproducibility, it is preferred to fabricate particles with continuous production.
Microfluidic and template (particle replication in non-wetting template, or PRINT,
etc.) methods are common protocols to achieve continuous production. This work
based on microfluidic production and CB[8]-ternary complex is an innovative
method to prepare microparticles for biomedical applications.
23.4.2 Inorganic/Composite Nanoparticles
Inorganic nanoparticles are prepared from metal or nonmetal precursors with controlled fabrication process to tune particle size and morphology. Gold, iron oxide,
and silica nanoparticles are among the most widely used inorganic nanoparticles. It
is relatively easier to control size and morphology for inorganic nanoparticles.
Importantly, inorganic nanoparticles often have interesting photo, thermal, magnetic
properties or porous characteristic for cargo loading. These characteristics render
inorganic nanoparticles major players in the field of drug delivery and bioimaging.
To take advantage of two or more types of materials, composite nanoparticles
have been used in biomedical applications. Composite nanomaterials are generally
composed of inorganic/inorganic and inorganic/polymeric nanoparticles. One of the
most representative types of composite nanomaterials is core-shell structured nanoparticles. Macrocyclic host molecules are of specific importance in the construction
of composite nanomaterials. Host molecules could be conveniently introduced to the
surface of nanoparticles for the purpose of modifying surface properties or as
gatekeepers to control the release of cargos.
Kim et al. used CB[7]-capped gold nanoparticles as a recognition-mediated
activation therapeutic system [32]. As shown in Fig. 14, hexanediamine-modified
gold nanoparticles (core size 2.5 Æ 0.4 nm) were capped with CB[7] by host-guest
interaction. These nanoparticles were nontoxic, which were readily taken up by
cells. TEM images confirmed that nanoparticles were internalized by cells and they
23 Stimuli-Responsive Self-Assembly Based on Macrocyclic Hosts and Biomedical. . .
623
drug delivery, sophisticated drug carrier is often desired, which could show complex
stimuli responsiveness. Therefore, supramolecular vesicles might be useful DDSs to
achieve specific targeted delivery purposes.
Microfluidic method is of great importance for particle fabrication and sensing.
Host-guest interaction may become a useful protocol to “cross-link” microparticles
in a supramolecular manner for microfluidic fabrication. Zhang et al. reported
one-step fabrication of supramolecular microcapsules from microfluidic droplets
based on CB[8]-ternary complexation [31]. Naphthalene-modified polymer, methyl
viologen-modified AuNP, and CB[8] were processed by microfluidic fabrication. CB
[8] would instantly form ternary complex with naphthalene and methyl viologen to
form highly uniform microcapsules. These microcapsules were characterized with
various techniques. Hydrophobic and hydrophilic cargos could be encapsulated in
the microcapsule wall and cavity, respectively. Surface-enhanced Raman spectroscopy (SERS) was used to characterize AuNP encapsulated inside microcapsules. To
prepare microparticles or nanoparticles with highly uniform composition, size, and
good reproducibility, it is preferred to fabricate particles with continuous production.
Microfluidic and template (particle replication in non-wetting template, or PRINT,
etc.) methods are common protocols to achieve continuous production. This work
based on microfluidic production and CB[8]-ternary complex is an innovative
method to prepare microparticles for biomedical applications.
23.4.2 Inorganic/Composite Nanoparticles
Inorganic nanoparticles are prepared from metal or nonmetal precursors with controlled fabrication process to tune particle size and morphology. Gold, iron oxide,
and silica nanoparticles are among the most widely used inorganic nanoparticles. It
is relatively easier to control size and morphology for inorganic nanoparticles.
Importantly, inorganic nanoparticles often have interesting photo, thermal, magnetic
properties or porous characteristic for cargo loading. These characteristics render
inorganic nanoparticles major players in the field of drug delivery and bioimaging.
To take advantage of two or more types of materials, composite nanoparticles
have been used in biomedical applications. Composite nanomaterials are generally
composed of inorganic/inorganic and inorganic/polymeric nanoparticles. One of the
most representative types of composite nanomaterials is core-shell structured nanoparticles. Macrocyclic host molecules are of specific importance in the construction
of composite nanomaterials. Host molecules could be conveniently introduced to the
surface of nanoparticles for the purpose of modifying surface properties or as
gatekeepers to control the release of cargos.
Kim et al. used CB[7]-capped gold nanoparticles as a recognition-mediated
activation therapeutic system [32]. As shown in Fig. 14, hexanediamine-modified
gold nanoparticles (core size 2.5 Æ 0.4 nm) were capped with CB[7] by host-guest
interaction. These nanoparticles were nontoxic, which were readily taken up by
cells. TEM images confirmed that nanoparticles were internalized by cells and they
23 Stimuli-Responsive Self-Assembly Based on Macrocyclic Hosts and Biomedical. . .
623