Rapid 3D bioprinting of a multicellular model recapitulating pterygium microenvironment.

Pterygium is an ocular surface disorder with high prevalence that can lead to vision impairment. As a pathological outgrowth of conjunctiva, pterygium involves neovascularization and chronic inflammation. Here, we developed a 3D multicellular in vitro pterygium model using a digital light processing (DLP)-based 3D bioprinting platform with human conjunctival stem cells (hCjSCs).

Compensating the cell-induced light scattering effect in light-based bioprinting using deep learning.

Digital light processing (DLP)-based three-dimensional (3D) printing technology has the advantages of speed and precision comparing with other 3D printing technologies like extrusion-based 3D printing. Therefore, it is a promising biomaterial fabrication technique for tissue engineering and regenerative medicine. When printing cell-laden biomaterials, one challenge of DLP-based bioprinting is the light scattering effect of the cells in the bioink, and therefore induce unpredictable effects on the photopolymerization process.

Bioprinting of dual ECM scaffolds encapsulating limbal stem/progenitor cells in active and quiescent statuses.

Limbal stem cell deficiency and corneal disorders are among the top global threats for human vision. Emerging therapies that integrate stem cell transplantation with engineered hydrogel scaffolds for biological and mechanical support are becoming a rising trend in the field. However, methods for high-throughput fabrication of hydrogel scaffolds, as well as knowledge of the interaction between limbal stem/progenitor cells (LSCs) and the surrounding extracellular matrix (ECM) are still much needed.

Rapid 3D Bioprinting of Glioblastoma Model Mimicking Native Biophysical Heterogeneity.

Glioblastoma multiforme (GBM) is the most lethal primary brain tumor characterized by high cellular and molecular heterogeneity, hypervascularization, and innate drug resistance. Cellular components and extracellular matrix (ECM) are the two primary sources of heterogeneity in GBM. Here, biomimetic tri-regional GBM models with tumor regions, acellular ECM regions, and an endothelial region with regional stiffnesses patterned corresponding to the GBM stroma, pathological or normal brain parenchyma, and brain capillaries, are developed.

Rapid bioprinting of conjunctival stem cell micro-constructs for subconjunctival ocular injection.

Ocular surface diseases including conjunctival disorders are multifactorial progressive conditions that can severely affect vision and quality of life. In recent years, stem cell therapies based on conjunctival stem cells (CjSCs) have become a potential solution for treating ocular surface diseases. However, neither an efficient culture of CjSCs nor the development of a minimally invasive ocular surface CjSC transplantation therapy has been reported.

3D printing of a biocompatible double network elastomer with digital control of mechanical properties.

The majority of 3D-printed biodegradable biomaterials are brittle, limiting their potential application to compliant tissues. Poly (glycerol sebacate) acrylate (PGSA) is a synthetic biodegradable and biocompatible elastomer, compatible with light-based 3D printing. In this work we employed digital-light-processing (DLP)-based 3D printing to create a complex PGSA network structure.

High-fidelity 3D Printing using Flashing Photopolymerization.

Photopolymerization-based 3D printing has emerged as a promising technique to fabricate 3D structures. However, during the printing process, polymerized materials such as hydrogels often become highly light-scattering, thus perturbing incident light distribution and thereby deteriorating the final print resolution. To overcome this scattering-induced resolution deterioration, we developed a novel method termed flashing photopolymerization (FPP).

A sequential 3D bioprinting and orthogonal bioconjugation approach for precision tissue engineering.

Recent advances in 3D bioprinting have transformed the tissue engineering landscape by enabling the controlled placement of cells, biomaterials, and bioactive agents for the biofabrication of living tissues and organs. However, the application of 3D bioprinting is limited by the availability of cytocompatible and printable biomaterials that recapitulate properties of native tissues. Here, we developed an integrated 3D projection bioprinting and orthogonal photoconjugation platform for precision tissue engineering of tailored microenvironments.

Three-dimensional bioprinted glioblastoma microenvironments model cellular dependencies and immune interactions.

Brain tumors are dynamic complex ecosystems with multiple cell types. To model the brain tumor microenvironment in a reproducible and scalable system, we developed a rapid three-dimensional (3D) bioprinting method to construct clinically relevant biomimetic tissue models. In recurrent glioblastoma, macrophages/microglia prominently contribute to the tumor mass.

Photopolymerizable Biomaterials and Light-Based 3D Printing Strategies for Biomedical Applications.

Since the advent of additive manufacturing, known commonly as 3D printing, this technology has revolutionized the biofabrication landscape and driven numerous pivotal advancements in tissue engineering and regenerative medicine. Many 3D printing methods were developed in short course after Charles Hull first introduced the power of stereolithography to the world. However, materials development was not met with the same enthusiasm and remained the bottleneck in the field for some time.

Rapid continuous 3D printing of customizable peripheral nerve guidance conduits.

Engineered nerve guidance conduits (NGCs) have been demonstrated for repairing peripheral nerve injuries. However, there remains a need for an advanced biofabrication system to build NGCs with complex architectures, tunable material properties, and customizable geometrical control. Here, a rapid continuous 3D-printing platform was developed to print customizable NGCs with unprecedented resolution, speed, flexibility, and scalability.

X-ray characterization of mesophases of human telomeric G-quadruplexes and other DNA analogues.

Observed in the folds of guanine-rich oligonucleotides, non-canonical G-quadruplex structures are based on G-quartets formed by hydrogen bonding and cation-coordination of guanosines. In dilute 5'-guanosine monophosphate (GMP) solutions, G-quartets form by the self-assembly of four GMP nucleotides. We use x-ray diffraction to characterize the columnar liquid-crystalline mesophases in concentrated solutions of various model G-quadruplexes.

Optical properties and electronic transitions of DNA oligonucleotides as a function of composition and stacking sequence.

The role of base pair composition and stacking sequence in the optical properties and electronic transitions of DNA is of fundamental interest. We present and compare the optical properties of DNA oligonucleotides (AT)10, (AT)5(GC)5, and (AT-GC)5 using both ab initio methods and UV-vis molar absorbance measurements. Our data indicate a strong dependence of both the position and intensity of UV absorbance features on oligonucleotide composition and stacking sequence.