3D Bioplotter Research Papers

The lack of an effective printable ink preparation method and the usual mechanically weak performance obstruct the functional 3D printing hydrogel exploitation and application. Herein, we propose a gentle pre-cross-linking strategy to enable a loosely cross-linked cellulose network for simultaneously achieving favorable printability and a strong hydrogel network via mediating the cellulose self-assembly. A small amount of epichlorohydrin is applied to (i) slightly pre-cross-link the cellulose chains for forming the percolating network to regulate the rheological properties and (ii) form the loosely cross-linked points to mediate the cellulose chains’ self-assembly for achieving superior mechanical properties. The fabrication of the complex…

Cellulose nanocrystals (CNCs), a type of natural photonic crystal, have been used to develop various optical materials owing to their chiral nematic organization, renewability, sustainability, and abundance. However, scaling up the production of CNC-based photonic materials remains challenging because of their long self-assembly time, inevitable assembly defects, static optical properties, and brittle nature. To address these drawbacks, the current study introduces flexible photonic hydrogels with chromatic patterns that are 3D printed using CNC-based inks. These viscoelastic inks were composed of photopolymerizable monomers and CNCs that harbored high aspect ratios. The luminance and color difference of the patterns in the photonic…

Intensively studied 3D printing technology is frequently hindered by the effective printable ink preparation method. Herein, we propose an elegant and gentle solvent consumption strategy to slowly disrupt the thermodynamic stability of the biopolymer (polysaccharide: cellulose, chitin, and chitosan) solution to slightly induce the molecule chains to in situ self-assemble into nanostructures for regulating the rheological properties, eventually achieving the acceptable printability. The polysaccharides are dissolved in the alkali/urea solvent. The weak Lewis acid fumed silica (as solvent mediator) is used to (i) slowly and partially consume the alkali/urea solvent to induce the polysaccharide chains to self-assemble into nanofibers to…

Bone defects remain a major threat to human health and bone tissue regeneration has become a prominent clinical demand worldwide. The combination of microRNA (miRNA) therapy with 3D printed scaffolds has always posed a challenge. It can mimic physiological bone healing processes, in which a biodegradable scaffold is gradually replaced by neo-tissue, and the sustained release of miRNA plays a vital role in creating an optimal osteogenic microenvironment, thus achieving promising bone repair outcomes. However, the balance between two key factors – scaffold degradation behavior and miRNA release profile – on osteogenesis and bone formation is still poorly understood. Herein,…

Inspired by stimuli-tailored dynamic processes that spatiotemporally create structural and functional diversity in biology, a new hierarchical patterning strategy is proposed to induce the emergence of complex multidimensional structures via dynamic sacrificial printing of stimuli-responsive hydrogels. Using thermally responsive gelatin (Gel) and pH-responsive chitosan (Chit) as proof-of-concept materials, we demonstrate that the initially printed sacrificial material (Gel/Chit-H+ hydrogel with a single gelatin network) can be converted dynamically into non-sacrificial material (Gel/Chit-H+–Citr hydrogel with gelatin and an electrostatic citrate–chitosan dual network) under stimulus cues (citrate ions). Complex hierarchical structures and functions can be created by controlling either the printing patterns of…

Hydrogel scaffolds are attractive for tissue defect repair and reorganization because of their human tissue-like characteristics. However, most hydrogels offer limited cell growth and tissue formation ability due to their submicron- or nano-sized gel networks, which restrict the supply of oxygen, nutrients and inhibit the proliferation and differentiation of encapsulated cells. In recent years, 3D printed hydrogels have shown great potential to overcome this problem by introducing macro-pores within scaffolds. In this study, we fabricated a macroporous hydrogel scaffold through horseradish peroxidase (HRP)-mediated crosslinking of silk fibroin (SF) and tyramine-substituted gelatin (GT) by extrusion-based low-temperature 3D printing. Through physicochemical characterization,…

Biology uses various cross-linking mechanisms to tailor material properties, and this is inspiring technological efforts to couple independent cross-linking mechanisms to create hydrogels with complex mechanical properties. Here, it is reported that a hydrogel formed from a single polysaccharide can be triggered to reversibly switch cross-linking mechanisms and switch between elastic and viscoelastic properties. Specifically, the pH-responsive self-assembling aminopolysaccharide chitosan is used. Under acidic conditions, chitosan is polycationic and can be electrostatically cross-linked by sodium dodecyl sulfate (SDS) micelles to confer viscoelastic and self-healing properties. Under basic conditions, chitosan becomes neutral, the electrostatic SDS–chitosan interactions are no longer operative, and…

Gelatin/Alginate hydrogels were engineered for bioplotting in tissue engineering. One major drawback of hydrogel scaffolds is the lack of adequate mechanical properties. In this study, using a bioplotter, we constructed the scaffolds with different pore architectures by deposition of gelatin/alginate hydrogels layer-by-layer. The scaffolds with different crosslinking degree were obtained by post-crosslinking methods. Their physicochemical properties, as well as cell viability, were assessed. Different crosslinking methods had little influence on scaffold architecture, porosity, pore size and distribution. By contrast, the water absorption ability, degradation rate and mechanical properties of the scaffolds were dramatically affected by treatment with various concentrations of…