Microcontainers

P. Chekhonin, I. R. Nazarova, and V. A. Kabanov. 1992. A new class of drug carriers micelles of poly(oxyethylene)-poly(oxypropylene) block copolymers as microcontainers for drug targeting from blood in brain.J. Control. Rel22 141-158. 

Possible approaches for enhancing drug influx in the BBB include (i) modification of a drug chemical structure, (ii) drug solubilization in nano- or microcontainers, and (iii) transient increase of BBB permeability. 

Kabanov, A.V., et al. 1989. The neuroleptic activity of haloperidol increases after its solubilization in surfactant micelles. Micelles as microcontainers for drug targeting. FEBS Lett 258 343. 

Figure 15.10 Biocompatible microfabrication allows trapping of a single bacterium. (A, B) SEM images of a bovine serum albumin microcontainer. (C) SEM of a container after the entrance was plugged with a bacterium inside. (D) Sequence showing the container before (1) and immediately after (2) fabrication of a plug to trap the bacterium (arrow scale bar, 10 pirn.). Cell division eventually fills the trap with no loss of bacteria (3-6) (reprinted with permission from [17] 2007 American Chemical Society).

Fig. 5. Electron micrograph of a microcontainment oxygen sensor (source ICB)...

Kabanov A, Batrakova E, Melik-Nubai ov N, Fedoseev N, Doroduich T, Alakliov V, Cheklionin V,Nazai ovaI, Kabanov V (1992a) Anew class of dmg carriers Micelles of poly(oxyediilene)-poly(oxupropilene) block copolymers as microcontainers for drug tai gedng from blood ill brain. J Control Release 22 141—158. 

The SBH microparticles were encapsulated within polymer films by the LBL self-assembly of oppositively charged polyelectrolytes (PEI and PABA). The polymer nanofilms fabrication was performed using dichloromethane as a working media. IR-spectroscopy was applied to investigate the chemical interaction between the polyelectrolytes. For preparation of the microcontainers, SBH powder was dispersed in DCM. PABA and PEI were adsorbed sequentially onto the surface of SBH particles. Finally, SBH particles were coated with three double layers of PABA and PEI. 

The microcontainer technique is a recently developed method for 3D cultures (Weibezahn et al, 1994). In this patented system cells grow on the vertical walls until a multicellular layer is formed. The containers are then transferred into a vessel and perfused continuously. A controlled supply of growth media of different compositions on each side of the layer allows the culture of highly differentiating ceU types and hence the establishment of tissue-like models. The full range of applications for this technique remains to be determined and it may well provide some useful in vitro tissue models in the future. 

Whilst the use of standard tissue culture flasks in glass or plastic has provided much of the data on which our understanding of in vitro cell biology is based, a very wide range of novel culture formats are now available for the benefit of those in basic research and biotechnology. Some of these approaches, notably filterwell culture, are now fairly commonplace but others, such as microcontainers and the RWV system, remain to have their full potential identified. Recent developments in the area of 3D cell culture have been rapid. It is evident that there is still much to be learned about the way cell function is modulated in 3D cell-cell and cell-matrix interactions. 

SONOCHEMICAL PROCESSES OF THE MICROCONTAINERS ENGINEERED WITH STABILIZED SILVER NANOPARTICLES... 

Furthermore, porous CPs (e.g., polypyrrole, polyanUine) films have been used as host matrices for polyelectrolyte capsules developed from composite material, which can combine electric conductivity of the polymer with controlled permeability of polyelectrolyte shell to form controllable micro- and nanocontainers. A recent example was reported by D.G. Schchukin and his co-workers [21]. They introduced a novel application of polyelectrolyte microcapsules as microcontainers with a electrochemically reversible flux of redox-active materials into and out of the capsule volume. Incorporation of the capsules inside a polypyrrole (PPy) film resulted in a new composite electrode. This electrode combined the electrocatalytic and conducting properties of the PPy with the storage and release properties of the capsules, and if loaded with electrochemical fuels, this film possessed electrochemically controlled switching between open and closed states of the capsule shell. This approach could also be of practical interest for chemically rechargeable batteries or fuel cells operating on an absolutely new concept. However, in this case, PPy was just utilized as support for the polyelectrolyte microcapsules. 

Moreover, Shi and his group reported electrochemical deposition of PPy microcontainers onto soap bubbles associated with O2 gas released from the electrolysis of H2O in an aqueous solution of /3-naphthalenesulfonic acid (/3-NSA), camphorsulfonic acid (CSA), or poly(styrene sulfonic acid) (PSSA), which act both the surfactant and dopant [79-81]. Morphologies such as bowls, cups, and bottles could be controlled by electrochemical conditions (Figure 11.6). However, the microcontainers were randomly located on the electrode surface, which limited further applications, Shi and coworkers reported a linear arrangement of PPy microcontainers by self-assembly with gas bubbles acting as templates on a silicon electrode surface patterned by photolithography [82]. They found that capillary interactions between the gas bubbles and the polymer photoresist walls led the microcontainers to be arranged linearly. 

To obtain nanocontainers, Wei et al. employed micelles as soft templates to assist the polymerization [83]. Hollow conical nanostructures are produced by a slow polymerization process (Figure 11.8). Microcontainers could be produced in the open or closed state by changing the polymerization time. However, as far as we are aware, most of the reported actuators were based on bulk materials or synergistic properties of nanostmcture bundles instead of single nanostmcture. Wei et al. realized the manipulation of separated nanocontainers by an electrochemical approach to control of the state of the nanocontainer in situ . Studying the switching of single nanostmctured CPs will open potential... 

Figure 11.6 SEM images of polypyrrole microcontainers synthesized electrochemical ly using a soap bubble -assisted soft-template method. (Reprinted with permission from Chemical Communications, Electrochemical synthesis of novel polypyrrole microstructures by L. T. Qu and G. Q. Shi, 2003, 2, 206-207. Copyright (2003) Royal Society of Chemistry)...

Figure 11.7 SEM images of polypyrrole microcontainers formed by soft-template polymerization under different electropolymerization conditions. (Reprinted with permission from Advanced Eunctional Materials, Conducting-polymer microcontainers Controlled syntheses and potential applications by V. Bajpai, P. G. He and L M. Dai, 14, 2, 145-151. Copyright (2004) Wiley-VCH)...

Figure 11.9 Folding sequence of a 500 mm microcontainer with opposite hinge layer configurations. (Reprinted with permission from Small, Thin Film Stress Driven Self-Folding of Microstructured Container by T.G. Leong et al., 4, 10, 1605-1609. Copyright (2008) WUey-VCH)...

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