Cyclodextrin-Based Microcapsules as Bioreactors for ATP Biosynthesis

Abstract

A biomimetic energy converter was fabricated via the assembly of CF 0 F 1 -ATPase on lipid-coated hollow nanocapsules composed of α-cyclodextrins/ chitosan-graf t-poly(ethylene glycol) methacrylate. Upon entrapped GOD into these capsules, the addition of glucose could trigger proton-motive force and then drive the rotation of ATPase to synthesize ATP.L iving organisms make a series of metabolisms every moment. An organism that wants to maintain activities needs a continuous supply of energy: adenosine triphosphate (ATP). As the energy currency, ATP induces large conformational changes in molecules such as myosin, kinesin, and chaperonin. With inspiration from biology, biological and biomimetic devices that supply ATP as energy, such as molecular motors and artificial cell bioreactors, have been developed. 1−4 However, in motility and functionality assays reported on these devices, the issue of ATP regulation is usually sidestepped by supplying ATP externally into the buffer solution. Complications can occur as high concentrations of ATP, and the devices stop operation when all the ATP runs out. For the long-term operation of more complex molecular devices, continual supply of the right amount of ATP is required.The enzyme primarily responsible for the production of ATP is the F 1 F 0 -type ATPase, which synthesizes ATP from adenosine diphosphate (ADP) and inorganic phosphate (Pi) by utilizing proton gradients. 5 Several groups have been working on the reconstitution of ATPase in liposomes as biomimetic systems to carry out ATP biosynthesis. 6−8 Although they have excellent assay characteristics, the future applicability of liposomes is intrinsically limited due to chemical and mechanical weaknesses. In order to get more stable and robust biomimetic membranes, polymersome and lipid bilayercoated microcapsules have been developed replacing traditional liposomes very recently. 9−12 For instance, Choi et al. demonstrated that synthesized amphiphilic polymersomes can replace liposomes for ATP synthesis. However, the synthesis needs strict control, and the assembled vesicles were not sufficiently stable. Li et al. introduced microcapsules fabricated by the layer-by-layer (LBL) assembly technique into the biomimetic system design and fabricated a series of biomimetic energy converters via the assembly of ATPase on lipid-coated hollow microcapsules. However, this strategy requires a procedure to remove the core in order to create a hollow interior and needs multiple steps to produce the wall of the microcapsules.In our previous study, we reported that polymeric hollow spheres with semipermeability could be obtained directly by self-assembly of rod−coil copolymers/cyclodextrin (CD) complexes in analogy to the cell membrane. 13−18 In the present work, we utilized this self-assembly approach to design a new type of biomimetic capsules for ATP synthesis. This capsule comprised a self-assembled hollow sphere as the inner support and its absorbed lipid as the out layer. Furthermore, glucose oxidases (GODs) were ent...

Immobilization of Aspergillus terreus lipase in self-assembled hollow nanospheres for enantioselective hydrolysis of ketoprofen vinyl ester

“…The spheres were constructed of alginate-graft-poly(ethylene glycol) (Alg-g-PEG) and ␣-cyclodextrin (␣-CD) . Besides, bioreactors via the assembly of CF 0 F 1 -ATPase on lipid-coated hollow nanocapsules were produced by ␣-cyclodextrins/chitosan-graft-poly(ethylene glycol) methacrylate (Li et al, 2013). The Alg-g-PEG/␣-CD hollow sphere is an excellent carrier because it not only can "swallow" enzyme molecules but also shows semi-permeability keeping enzymes inside while permitting substrates and products to pass though.…”

Visible Thrombolysis Acceleration of a Nanomachine Powered by Light-Driving F0F1-ATPase Motor

“…Li et al entrapped glucose oxidases (GODs) into the cavity of polymeric hollow spheres of biomimetic nanocapsules, which can hydrolyze glucose in the suspension and produce proton gradient, thus supply power for ATPase. In comparison to our light-driven proton pump, this type of biomimetic capsule for ATP synthesis maybe a cheaper and better choice for the future study [ 31 ].…”

Light-Driven Biocatalysis in Liposomes and Polymersomes: Where Are We Now?

“…ATP is generated by F 0 F 1 -ATP synthases in living organisms in two ways: (1) oxidative phosphorylation and (2) photophosphorylation via light-induced proton gradients [116][117][118]. ATP synthases have been reported to be functionally reconstituted within artificial vesicles, e.g., liposomes [13][14][15]19,20,77,119], polymersomes [54,70,71], as well as within protein-or polymer-based microcapsules [120][121][122]. ATP synthesis was powered by the proton gradients generated by coupling with BR [12,14,54,70,71,77,119], PSII/PR [20], PSII [19], and artificial RC [15].…”