Supramolecularly Assembled Nanocomposites as Biomimetic Chloroplasts for Enhancement of Photophosphorylation.

Prototypes of natural biosystems provide opportunities for artificial biomimetic systems to break the limits of natural reactions and achieve output control. However, mimicking unique natural structures and ingenious functions remains a challenge. Now, multiple biochemical reactions were integrated into artificially designed compartments via molecular assembly. First, multicompartmental silica nanoparticles with hierarchical structures that mimic the chloroplasts were obtained by a templated synthesis. Then, photoacid generators and ATPase-liposomes were assembled inside and outside of silica compartments, respectively. Upon light illumination, protons produced by a photoacid generator in the confined space can drive the liposome-embedded enzyme ATPase towards ATP synthesis, which mimics the photophosphorylation process in vitro. The method enables fabrication of bioinspired nanoreactors for photobiocatalysis and provides insight for understanding sophisticated biochemical reactions.

Self-organization of honeycomb-like porous TiO2 films by means of the breath-figure method for surface modification of titanium implants.

This study describes a facile breath-figure method for the preparation of honeycomb-like porous TiO2 films with an organometallic small-molecule precursor. Multiple characterization techniques have been used to investigate the porous films and a mechanism for the formation process of porous TiO2 films through the breath-figure method is proposed. The pore size of the TiO2 films could be modulated by varying the experimental parameters, such as the concentration of titanium n-butoxide (TBT) solution, the content of cosolvent, and the air flow rate. In vitro cell-culture experiments indicate that NIH 3T3 fibroblast cells seeded on the honeycomb-like porous TiO2 films show good adhesion, spreading, and proliferation behaviors, which suggests that honeycomb-like porous TiO2 films are an attractive biomaterial for surface modification of titanium and its alloys implants in tissue engineering to enhance their biocompatibility and bioactivity.

Biotinylated lipid membrane patterns supported by proteins for the recognition of streptavidined polystyrene microspheres.

Human serum albumin (HSA) patterns constructed on glass substrate by the micro-contact printing (microCP) technique are fabricated to support phospholipids membranes functionalized with biotinylated lipid. The experiment results indicate that this kind of lipid membrane has been assembled on HSA patterns with good stability. And the streptavidin-coated PS microspheres can be deposited on such lipid patterns with high efficiency. In this way, it may create a route to change the biological interface in the fabrication of biosensor.

Supramolecular Assembly of Photosystem II and Adenosine Triphosphate Synthase in Artificially Designed Honeycomb Multilayers for Photophosphorylation.

Plant thylakoids have a typical stacking structure, which is the site of photosynthesis, including light-harvesting, water-splitting, and adenosine triphosphate (ATP) production. This stacking structure plays a key role in exchange of substances with extremely high efficiency and minimum energy consumption through photosynthesis. Herein we report an artificially designed honeycomb multilayer for photophosphorylation. To mimic the natural thylakoid stacking structure, the multilayered photosystem II (PSII)-ATP synthase-liposome system is fabricated via layer-by-layer (LbL) assembly, allowing the three-dimensional distributions of PSII and ATP synthase. Under light illumination, PSII splits water into protons and generates a proton gradient for ATP synthase to produce ATP. Moreover, it is found that the ATP production is extremely associated with the numbers of PSII layers. With such a multilayer structure assembled via LbL, one can better understand the mechanism of PSII and ATP synthase integrated in one system, mimicking the photosynthetic grana structure. On the other hand, such an assembled system can be considered to improve the photophosphorylation.

Rational assembly of a biointerfaced core@shell nanocomplex towards selective and highly efficient synergistic photothermal/photodynamic therapy.

To optimize synergistic cancer therapy, we rationally assemble an inorganic-organic nanocomplex using a folate-modified lipid bilayer spread on photosensitizer-entrapped mesoporous silica nanoparticle (MSN) coated gold nanorods (AuNRs). In this hybrid bioconjugate, the large specific surface area and pore size of AuNR@MSN guarantee a high loading capacity of small photosensitive molecules. The modification with selective mixed liposomes on the surface of AuNR@MSN enables faster cellular internalization and enhancement of endocytosis. Under one-time NIR two-photon illumination, AuNR-mediated hyperthermia can kill cancer cells directly. Meanwhile, the loaded photosensitizer, hypocrellin B, generates two kinds of reactive oxygen species (ROS) to induce cell apoptosis. Remarkably, hyperthermia can improve the yield of ROS. After intravenous injection of this bioconjugate into female BALB/c nude mice followed by laser irradiation (808 nm, 1.3 W cm(-2), 6 min), the tumor growth is suppressed completely. The tumors are not recurrent within the observation time (19 days), and the normal or main organs are not obviously pathological. Thus, such a simplified and selective cancer treatment, combining photothermal and photodynamic therapy in a synergistic manner, provides outstanding efficiency in vivo. This nanocomplex with well-defined core@shell nanostructures integrated with a two-photon technique holds great promise to improve cancer phototherapy with a high efficiency in the clinic.

Alginate-based microcapsules with a molecule recognition linker and photosensitizer for the combined cancer treatment.

A reactive template method was used to fabricate alginate-based hydrogel microcapsules. The uniform and well-dispersed hydrogel capsules have a high drug loading capacity. After they are coated by a folate-linked lipid mixture on the surface, the capsules possess higher cell uptake efficiency by the molecule recognition between folate and the folate-receptor overexpressed by the cancer cells. Moreover, in this bioconjugate, the lipid could remarkably reduce the release rate of hydrophilic doxorubicin from the hydrogel microcapsules and encapsulate the hydrophobic photosensitizer hypocrellin B. The biointerfaced capsules could be used as drug carriers for combined treatment against cancer cell proliferation in vitro; this was much more effective than chemotherapy or photodynamic therapy alone.

pH-responsive polysaccharide microcapsules through covalent bonding assembly.

Biocompatible and biodegradable microcapsules were fabricated by the covalent assembly of polysaccharides and their derivatives. The formation of Schiff's bases between polysaccharides and their derivatives enabled the microcapsules' autofluorescence properties and pH-responsivity. These polysaccharide microcapsules have great potential applications in biological tracing and drug delivery.