Engineering in vitro vascular microsystems.

Blood vessels are hierarchical microchannels that transport nutrients and oxygen to different tissues and organs, while also eliminating metabolic waste from the body. Disorders of the vascular system impact both physiological and pathological processes. Conventional animal vascular models are complex, high-cost, time-consuming, and low-validity, which have limited the exploration of effective in vitro vascular microsystems.

A closed-loop modular multiorgan-on-chips platform for self-sustaining and tightly controlled oxygenation.

To mimic physiological microenvironments in organ-on-a-chip systems, physiologically relevant parameters are required to precisely access drug metabolism. Oxygen level is a critical microenvironmental parameter to maintain cellular or tissue functions and modulate their behaviors. Current organ-on-a-chip setups are oftentimes subjected to the ambient incubator oxygen level at 21%, which is higher than most if not all physiological oxygen concentrations.

Thiophene donor for NIR-II fluorescence imaging-guided photothermal/photodynamic/chemo combination therapy.

Organic fluorophores/photosensitizers have been widely used in biological imaging and photodynamic and photothermal combination therapy in the first near-infrared (NIR-I) window. However, their applications in the second near-infrared (NIR-II) window are still limited primarily due to low fluorescence quantum yields (QYs). Here, a boron dipyrromethene (BDP) is created as a molecularly engineered thiophene donor unit with high QYs to the redshift.

Symbiotic Photosynthetic Oxygenation within 3D-Bioprinted Vascularized Tissues.

In this study, we present the photosynthetic oxygen (O) supply to mammalian cells within a volumetric extracellular matrix-like construct, whereby a three-dimensional (3D)-bioprinted fugitive pattern encapsulating unicellular green algae, (), served as a natural photosynthetic O-generator. The presence of bioprinted enhanced the viability and functionality of mammalian cells while reducing the hypoxic conditions within the tissues. We were able to subsequently endothelialize the hollow perfusable microchannels formed after enzymatic removal of the bioprinted -laden patterns from the matrices following the initial oxygenation period, to obtain biologically relevant vascularized mammalian tissue constructs.

Bioprinted Injectable Hierarchically Porous Gelatin Methacryloyl Hydrogel Constructs with Shape-Memory Properties.

Direct injection of cell-laden hydrogels shows high potentials in tissue regeneration for translational therapy. The traditional cell-laden hydrogels are often used as bulk space fillers to tissue defects after injection, likely limiting their structural controllability. On the other hand, patterned cell-laden hydrogel constructs often necessitate invasive surgical procedures.

Near-Infrared-II Nanoparticles for Cancer Imaging of Immune Checkpoint Programmed Death-Ligand 1 and Photodynamic/Immune Therapy.

Development of second near-infrared (NIR-II) nanoparticles (NPs) with high biocompatibility, low toxicity, and high singlet oxygen quantum yield (Φ) to prevent tumor recurrence is highly desirable in molecular imaging and photodynamic/immune combination therapy. Here, theranostic photosensitizer BODIPY (BDP)-I-N-anti-PD-L1 NPs were developed by encapsulating the photosensitizer BDP-I-N with amphipathic poly(styrene--chloromethylstyrene)--poly(ethylene glycol) nanocarriers through self-assembly functionalization with programmed cell death-ligand 1 (PD-L1) monoclonal antibody. These NPs exhibit highly intensive luminescence in the NIR-II window (1000-1700 nm) to real-time imaging of immune checkpoint PD-L1, high singlet oxygen quantum yield (Φ = 73%), and an eliminating effect of primary cancers.

A Tumor-on-a-Chip System with Bioprinted Blood and Lymphatic Vessel Pair.

Current anti-tumor drug screening strategies are insufficiently portrayed lacking true perfusion and draining microcirculation systems, which may post significant limitation in reproducing the transport kinetics of cancer therapeutics explicitly. Herein, we report the fabrication of an improved tumor model consisting of bioprinted hollow blood vessel and lymphatic vessel pair, hosted in a three-dimensional (3D) tumor microenvironment-mimetic hydrogel matrix, termed as the tumor-on-a-chip with bioprinted blood and lymphatic vessel pair (TOC-BBL). The bioprinted blood vessel was perfusable channel with opening on both ends while the bioprinted lymphatic vessel was blinded on one end, both of which were embedded in a hydrogel tumor mass, with vessel permeability individually tunable through optimization of the composition of the bioinks.

A miniaturized optical tomography platform for volumetric imaging of engineered living systems.

Volumetric optical microscopy approaches that enable acquisition of three-dimensional (3D) information from a biological sample are attractive for numerous non-invasive imaging applications. The unprecedented structural details that these techniques provide have helped in our understanding of different aspects of architecture of cells, tissues, and organ systems as they occur in their natural states. Nonetheless, the instrumentation for most of these techniques is sophisticated, bulky, and costly, and is less affordable to most laboratory settings.

Tacrolimus- and Nerve Growth Factor-Treated Allografts for Neural Tissue Regeneration.

Treatment of injured peripheral nerves, especially long-distance nerve defects, remains a significant challenge in regenerative medicine due to complex biological conditions and a lack of biomaterials for effective nerve reconstruction. Without proper treatment, nerve injury leads to motor and sensory dysfunction. Here, we have developed an efficacious nerve allograft treated with a dual drug containing acrolimus and nerve growth factor to bridge the nerve gap and achieve rapid neural tissue recovery without immunological rejection.

Aqueous Two-Phase Emulsion Bioink-Enabled 3D Bioprinting of Porous Hydrogels.

3D bioprinting technology provides programmable and customizable platforms to engineer cell-laden constructs mimicking human tissues for a wide range of biomedical applications. However, the encapsulated cells are often restricted in spreading and proliferation by dense biomaterial networks from gelation of bioinks. Herein, a cell-benign approach is reported to directly bioprint porous-structured hydrogel constructs by using an aqueous two-phase emulsion bioink.

A bilayered nanoshell for durable protection of single yeast cells against multiple, simultaneous hostile stimuli.

Single cell surface engineering provides the most efficient, non-genetic strategy to enhance cell stability. However, it remains a huge challenge to improve cell stability in complex artificial environments. Here, a soft biohybrid interfacial layer is fabricated on individual living-cell surfaces by their exposure to a suspension of gold nanoparticles and l-cysteine to form a protecting functional layer to which porous silica layers were bound yielding pores with a diameter of 3.

A stable, reusable, and highly active photosynthetic bioreactor by bio-interfacing an individual cyanobacterium with a mesoporous bilayer nanoshell.

An individual cyanobacterium cell is interfaced with a nanoporous biohybrid layer within a mesoporous silica layer. The bio-interface acts as an egg membrane for cell protection and growth of outer shell. The resulting bilayer shell provides efficient functions to create a single cell photosynthetic bioreactor with high stability, reusability, and activity.

"Self-repairing" nanoshell for cell protection.

Self-repair is nature's way of protecting living organisms. However, most single cells are inherently less capable of self-repairing, which greatly limits their wide applications. Here, we present a self-assembly approach to create a nanoshell around the cell surface using nanoporous biohybrid aggregates.

Amino acid-based biohybrids for nano-shellization of individual desulfurizing bacteria.

Amino acid-based biohybrids have been developed to self-assemble on the surface of desulfurizing bacteria to form nanothin and nanoporous shells. The shells not only endow the encapsulated cells with reusability, but also offer platforms to incorporate titania and magnetic nanoparticles to improve the desulfurizing activity and the separation efficiency.