Photoresponsive prodrug-based liposomes for controllable release of the anticancer drug chlorambucil.

The on-demand delivery and release of chemotherapeutic drugs have attracted great attention, among which photoresponsive prodrug systems have shown specific advantages for effective cancer treatment due to their spatiotemporal control, non-invasive nature and easy operation. Unlike the traditional strategy of physical encapsulation of drugs in liposomes, we herein report a biomimetic and photoresponsive drug delivery system (DDS) based on a lipid prodrug liposomal formulation (LNC), which combines the features of the prodrug and nanomedicines, and can realize photocontrollable release of anticancer drugs. The lipid prodrug comprises three functional moieties: a single-arm phospholipid (Lyso PC), an -nitrobenzyl alcohol (NB) and chlorambucil (CBL).

Folding and Unfolding of a Fully Synthetic Transmembrane Receptor for ON/OFF Signal Transduction.

Signal transduction processes in living organisms are mainly transmitted through conformational changes in transmembrane protein receptors. So far, the development of signal transduction models induced by artificial simulation of conformational changes remains limited. We herein report a new artificial receptor that achieves controllable "ON/OFF" signal transduction through conformational changes between the folding and unfolding of a transmembrane foldamer moiety.

3D Embedded Printing of Complex Biological Structures with Supporting Bath of Pluronic F-127.

Biofabrication is crucial in contemporary tissue engineering. The primary challenge in biofabrication lies in achieving simultaneous replication of both external organ geometries and internal structures. Particularly for organs with high oxygen demand, the incorporation of a vascular network, which is usually intricate, is crucial to enhance tissue viability, which is still a difficulty in current biofabrication technology.

Extracellular Matrix-Mimetic Immunomodulatory Hydrogel for Accelerating Wound Healing.

Macrophages play a crucial role in the complete processes of tissue repair and regeneration, and the activation of M2 polarization is an effective approach to provide a pro-regenerative immune microenvironment. Natural extracellular matrix (ECM) has the capability to modulate macrophage activities via its molecular, physical, and mechanical properties. Inspired by this, an ECM-mimetic hydrogel strategy to modulate macrophages via its dynamic structural characteristics and bioactive cell adhesion sites is proposed.

sp. nov. (Teleostei: Nemacheilidae), a New Troglomorphic Loach from Guangxi, China.

A new species of the genus is described based on specimens from a karst cave in Andong Town, Xincheng County, Liuzhou City, Guangxi, China. sp. nov.

A rigid-axle-based molecular rotaxane channel facilitates K/Cl co-transport across a lipid membrane.

Inspired by the design criteria of heteroditopic receptors for ion-pair binding, we herein describe a new strategy to construct a rotaxane transporter (RR[2]) for K/Cl co-transport. The use of a rigid axle improves the transport activity with an EC value of 0.58 μM, presenting a significant step toward developing rotaxane artificial channels.

A Facile and Versatile Approach to Construct Photoactivated Peptide Hydrogels by Regulating Electrostatic Repulsion.

Short peptides that can respond to external stimuli have been considered as the preferred building blocks to construct hydrogels for biomedical applications. In particular, photoresponsive peptides that are capable of triggering the formation of hydrogels upon light irradiation allow the properties of hydrogels to be changed remotely by precise and localized actuation. Here, we used the photochemical reaction of the 2-nitrobenzyl ester group (NB) to develop a facile and versatile strategy for constructing photoactivated peptide hydrogels.

A Light-Driven Molecular Machine Controls K Channel Transport and Induces Cancer Cell Apoptosis.

The design of artificial ion channels with high activity, selectivity and gating function is challenging. Herein, we designed the light-driven motor molecule MC2, which provides new design criteria to overcome these challenges. MC2 forms a selective K channel through a single molecular transmembrane mechanism, and the light-driven rotary motion significantly accelerates ion transport, which endows the irradiated motor molecule with excellent cytotoxicity and cancer cell selectivity.

A system for artificial light signal transduction molecular translocation in a lipid membrane.

Light signal transduction pathways are the central components of mechanisms that regulate plant development, in which photoreceptors receive light and participate in light signal transduction. Chemical systems can be designed to mimic these biological processes that have potential applications in smart sensing, drug delivery and synthetic biology. Here, we synthesized a series of simple photoresponsive molecules for use as photoreceptors in artificial light signal transduction.

Highly Tough, Stretchable, and Enzymatically Degradable Hydrogels Modulated by Bioinspired Hydrophobic β-Sheet Peptides.

Peptide-based supramolecular hydrogels have attracted great attention due to their good biocompatibility and biodegradability and have become promising candidates for biomedical applications. The bottom-up self-assembly endows the peptides with a highly ordered secondary structure, which has proven to be an effective strategy to improve the mechanical properties of hydrogels through strong physical interactions and energy dissipation. Inspired by the excellent mechanical properties of spider-silk, which can be attributed to the rich β-sheet crystal formation by the hydrophobic peptide fragment, a hydrophobic peptide (HP) that can form a β-sheet assembly was designed and introduced into a poly(vinyl alcohol) (PVA) scaffold to improve mechanical properties of hydrogels by the cooperative intermolecular physical interactions.

Precise macroscopic supramolecular assembly of photopatterned hydrogels.

Here we demonstrate that a precise macroscopic supramolecular assembly (MSA) can be achieved using a surface photopatterning strategy. The electrostatic interaction of the photopatterned polyelectrolytes drives hydrogel cuboids to form a stable MSA on a millimeter scale and the spatial controllability of light enables the hydrogels to be assembled into complex supramolecular architectures.

formation of a biomimetic lipid membrane triggered by an aggregation-enhanced photoligation chemistry.

Nature or synthetic systems that can self-assemble into biomimetic membranes and form compartments in aqueous solution have received extensive attention. However, these systems often have the problems of requiring complex processes or lacking of control in simulating lipid synthesis and membrane formation of cells. This paper demonstrates a conceptually new strategy that uses a photoligation chemistry to convert nonmembrane molecules to yield liposomes.

A Synthetic Phospholipid Derivative Mediates Ion Transport Across Lipid Bilayers.

Inspired by the natural phospholipid structures for cell membrane, a synthetic phospholipid with an ion recognition group benzo-18-crown-6 (B18C6) moiety was prepared which has been demonstrated to be able to transport ions across the lipid bilayers. Fluorescent vesicle assay shows that has an excellent transport activity, and the EC value for K is 11.2 μM.

A Light-Operated Molecular Cable Car for Gated Ion Transport.

Inspired by the nontrivial and controlled movements of molecular machines, we report an azobenzene-based molecular shuttle PR2, which can perform light-gated ion transport across lipid membranes. The amphiphilicity and membrane-spanning molecular length enable PR2 to insert into the bilayer membrane and efficiently transport K (EC =4.1 μm) through the thermally driven stochastic shuttle motion of the crown ether ring along the axle.

Tag-Free Site-Specific BMP-2 Immobilization with Long-Acting Bioactivities via a Simple Sugar-Lectin Interaction.

The construction of a biomaterial matrix with biological properties is of great importance to developing functional materials for clinical use. However, the site-specific immobilization of growth factors to endow materials with bioactivities has been a challenge to date. Considering the wide existence of glycosylation in mammalian proteins or recombinant proteins, we establish a bioaffinity-based protein immobilization strategy (bioanchoring method) utilizing the native sugar-lectin interaction between concanavalin A (Con A) and the oligosaccharide chain on glycosylated bone morphogenetic protein-2 (GBMP-2).

Hyaluronic acid-based antibacterial hydrogels constructed by a hybrid crosslinking strategy for pacemaker pocket infection prevention.

In this study, we developed an injectable antibacterial hydrogel based on hyaluronic acid (HA) and chlorhexidine (CHX) for cardiovascular implantable electronic device (CIED) infection treatment. To balance stability and moldability, the HA scaffold was pre-crosslinked by 1,4-butanediol diglycidyl ether (BDDE) and then ground to form an HA microgel (CHA). Then, the antibacterial agent CHX was further crosslinked in the CHA microgel through electrostatic interactions between CHA and CHX to obtain hybrid crosslinked hydrogels (CHA/CHX).

Photo and Reduction Dual-Responsive Hydrogel for Regulating Cell Adhesion and Cell Sheet Harvest.

Regulating cell-surface interactions plays a key role for biomaterials and their applications in cell-based therapies. In this paper, we demonstrated a dual-responsive hydrogel platform to achieve phototriggered protein immobilization and reduction-induced protein release. By -nitrobenzyl photochemistry, including sequential aldehyde generation upon light irradiation and imine ligation with amine compounds, adhesive proteins can be effectively immobilized on the hydrogel with spatial and quantitative control, thus mediating cell adhesion in designed areas.

Phototriggered labeling and crosslinking by 2-nitrobenzyl alcohol derivatives with amine selectivity.

Here we report the use of 2-nitrobenzyl alcohol (NB) as a photoreactive group with amine selectivity and explore its applications for photoaffinity labeling and crosslinking of biomolecules. This work confirms that NB is an efficient photoreactive group and has great potential in drug discovery, chemical biology and protein engineering.

Light-responsive polymersomes with a charge-switch for targeted drug delivery.

Unlike the traditional block amphiphilic polymersomes, we herein report a lipid-like amphiphilic polymer that self-assembles into photo-responsive polymersomes for drug delivery. The introduction of a quaternary ammonium moiety not only provides a hydrophilic segment of the polymersomes, but also enables electrostatic adsorption with folic acid, thus achieving the targeting of cancer cells with overexpression of folate receptor. Upon light irradiation, the photocleavage reaction of the o-nitrobenzyl moiety disintegrates polymersomes by changing the polymer structure from cationic amphiphilic state to zwitterionic hydrophilic state, thus realizing photo-triggered drug release.

Helical supramolecular polymer nanotubes with wide lumen for glucose transport: towards the development of functional membrane-spanning channels.

The manipulation of strong noncovalent interactions provides a concise and versatile strategy for constructing highly ordered supramolecular structures. By using a shape-persistent building block consisting of phenanthroline derivatives and two quadruply hydrogen-bonding AADD moieties, a type of precise helical supramolecular polymer (HSP) nanotube has been developed. The helical conformation of the supramolecular polymers has been proved various techniques, showing significantly expanded topologies of supramolecular polymers.

Using MODIS Land Surface Temperatures for Permafrost Thermal Modeling in Beiluhe Basin on the Qinghai-Tibet Plateau.

It is essential to monitor the ground temperature over large areas to understand and predict the effects of climate change on permafrost due to its rapid warming on the Qinghai-Tibet Plateau (QTP). Land surface temperature (LST) is an important parameter for the energy budget of permafrost environments. Moderate Resolution Imaging Spectroradiometer (MODIS) LST products are especially valuable for detecting permafrost thermal dynamics across the QTP.

Visualizing RNA dynamics in live cells with bright and stable fluorescent RNAs.

Fluorescent RNAs (FRs), aptamers that bind and activate fluorescent dyes, have been used to image abundant cellular RNA species. However, limitations such as low brightness and limited availability of dye/aptamer combinations with different spectral characteristics have limited use of these tools in live mammalian cells and in vivo. Here, we develop Peppers, a series of monomeric, bright and stable FRs with a broad range of emission maxima spanning from cyan to red.

Moldable and Removable Wound Dressing Based on Dynamic Covalent Cross-Linking of Thiol-Aldehyde Addition.

The development of a moldable and removable gel technique for wound dressing is becoming highly desirable. Herein, we describe a facile method to generate an adaptable and dissolvable network of PEG-thiols and aldehyde groups in oxidized dextran. The dynamic covalent chemistry of the thiol-aldehyde addition reaction provides hydrogels with typical rheological behavior and thus endows the hydrogels with an excellent adaptability for the initial operation of wound coverage.

Photosensitive Hydrogel Creates Favorable Biologic Niches to Promote Spinal Cord Injury Repair.

Photochemistry is considered to be a promising strategy for hydrogels to mimic the complex and dynamic properties of natural extracellular matrix. However, it is seldom applied in 3D tissue engineering and regenerative medicine due to the attenuation of light. In this study, phenyl azide photchemistry and optical fiber technology are first used to localize adhesive protein on the inner surface of the nerve guidance conduit in a 3D hydrogel scaffold.