[en] Self-assembling bioinks offer the possibility to biofabricate with molecular precision, hierarchical control, and biofunctionality. For this to become a reality with widespread impact, it is essential to engineer these ink systems ensuring reproducibility and providing suitable standardization. We have reported a self-assembling bioink based on disorder-to-order transitions of an elastin-like recombinamer (ELR) to co-assemble with graphene oxide (GO). Here, we establish reproducible processes, optimize printing parameters for its use as a bioink, describe new advantages that the self-assembling bioink can provide, and demonstrate how to fabricate novel structures with physiological relevance. We fabricate capillary-like structures with resolutions down to ∼10 µm in diameter and ∼2 µm thick tube walls and use both experimental and finite element analysis to characterize the printing conditions, underlying interfacial diffusion-reaction mechanism of assembly, printing fidelity, and material porosity and permeability. We demonstrate the capacity to modulate the pore size and tune the permeability of the resulting structures with and without human umbilical vascular endothelial cells. Finally, the potential of the ELR-GO bioink to enable supramolecular fabrication of biomimetic structures was demonstrated by printing tubes exhibiting walls with progressively different structure and permeability. (paper)

[en] Highlights: • Biomimetic and mechanically stable nanocomposite fibrous scaffold was developed. • The fibrous scaffold promoted new bone formation in critical sized rabbit mandibular defect. • It also enhanced osseointegration with Ti dental implants, suggesting its usage for alveolar ridge augmentation. -- Abstract: Implant-supported dental prosthesis in patients with edentulism or those with reconstructed bone have long survival rate, but the success depends largely on the quality and quantity of the available bone at the recipient site. The usage of autograft is the gold standard treatment for vertical bone augmentation, but it has many limitations. In this study, we have developed a nanocomposite fibrous scaffold [silica coated nanoHA-gelatin reinforced with electrospun poly(L-lactic acid) (PLLA) nanoyarns] and evaluated its efficacy to promote osseointegration in rabbit mandibular defect in comparison to the scaffold without fibers and commercial nanoHA-collagen graft. For this, critical sized bilateral defect (10 mm length, 3 mm depth and 3 mm width) was created in rabbit mandible and dental implantation was done in two manners. In strategy 1, Ti dental implant was placed along with the scaffold and in strategy 2, the scaffold was implanted for 3 months to facilitate new bone formation followed by Ti dental implantation. In strategy 2, the fibrous scaffold could promote new bone formation and osseointegration in rabbit mandibular defect when compared to the scaffolds without fibers and commercial graft, but strategy 1 was not successful. These findings demonstrated that nanocomposite fibrous scaffold is a promising biomaterial to promote new bone formation and osseointegration in mandibular defect.

[en] Highlights: • The CHA used in the current study show poor biocompatibility. • The biocompatibility of CHA is improved by either coating with a layer of OCP or by adding BMP-2. • CHA modified by OCP coating with BMP-2 show improved biocompatibility and osteoinductive. -- Abstract: (1) To determine whether the biocompatibility of coralline hydroxyapatite (CHA) granules could be improved by using an octacalcium phosphate (OCP) coating layer, and/or functionalized with bone morphogenetic protein 2 (BMP-2), and (2) to investigate if BMP-2 incorporated into this coating is able to enhance its osteoinductive efficiency, in comparison to its surface-adsorbed delivery mode.

[en] Highlights: • A fiber composite material exhibits multimodal shear and tension micromechanics. • Gene expression of tenocytes is insensitive to fiber stiffness or YRGDS vs DGEA. • Tendon marker and collagen genes are insensitive to fiber environment under strain. • MMP3 and IL6 genes are sensitive to fiber stiffness and peptide under cyclic strain. • Healthy tenocytes rapidly respond to their environment by a catabolic response. We recently developed a fiber composite consisting of tenocytes seeded onto discontinuous fibers embedded within a hydrogel, designed to mimic physiological tendon micromechanics of tension and shear. This study examined if cell adhesion peptide (DGEA or YRGDS), fiber modulus (50 or 1300 kPa) and/or cyclic strain (5% strain, 1 Hz) influenced bovine tenocyte gene expression. Ten genes were analyzed and none were sensitive to peptide or fiber modulus in the absence of cyclic tensile strain. Genes associated with tendon (SCX and TNMD), collagens (COL1A1, COL3A1, COL11A1), and matrix remodelling (MMP1, MMP2, and TIMP3) were insensitive to cyclic strain. Contrarily, cyclic strain up-regulated IL6 by 30-fold and MMP3 by 10-fold in soft YRGDS fibers. IL6 expression in soft YRGDS fibers was 5.7 and 3.3-fold greater than in soft DGEA fibers and stiff RGD fibers, respectively, under cyclic strain. Our findings suggest that changes in the surrounding matrix can influence catabolic genes in tenocytes when cultured in a complex strain environment mimicking that of tendon, while having minimal effects on tendon and homeostatic genes.

[en] Three-dimensional (3D) printing shows potential for use as an advanced technology for forming biomimetic tissue and other complex structures. However, there are limits and restrictions on selection of conventional bioinks. Here we report the first 3D-printable platelet lysate (PLMA)-based hydrogel, which consists of platelet lysate from whole blood of humans that can simulate the 3D structure of tissues and can be formed into a crosslinked hydrogel layer-by-layer to build cell-laden hydrogel constructs through methacrylated photo-polymerization. Furthermore, it can be customized for use with various tissues by controlling the physical properties according to irradiation time and concentration. In particular, different cells can be mixed and printed, and the integrity of the 3D printed structure can maintain its shape after crosslinking. The bio-ink exhibits excellent cell diffusion and proliferation at low concentrations, which improves moldability and biocompatibility. The 3D-printable PLMA bioinks may constitute a new strategy to create customized microenvironments for the repair of various tissues in vivo using materials derived from the human body. (paper)

[en] The nano-particles are not limited to the domain of physics rather it is now days used for the applications in information technology and bio-informatics whereby the assorted streams can be integrated. In this research paper, the analysis of the nano-particles related to the brain waves are taken so that the predictions on the datasets can be done for effective discovery and identification of the brain related diseases. This manuscript is having focus on the usage of machine learning based approach for the predictive analysis of the brain related diseases and found that the need to integrate the information technology to biological domains are quite mandatory for the medical sciences. (paper)

[en] Highlights: • A review is presented on recent research on biological armours that can be mimicked using additive manufacturing. • Classification of the biomimetic armours according to the load condition. • Modified biomimicry design spiral for additive manufacturing is discussed. • The future prospects of bioinspired armour structures based on additive manufacturing are presented. Nature has a wide range of biological protection strategies that show resilience to impact loading. These strategies also serve a certain amount of flexibility that contribute to body movement and locomotion. Consequently, researchers have developed biomimetic engineering structures emulating natural strategies. However, biological entities are often complex and are difficult to replicate with conventional manufacturing technologies. Recent advances in additive manufacturing provide a pathway to emulate the hierarchical architectures of biological materials. In this review paper, we consider biological structures from marine and terrestrial animals that safeguard their body parts from external attack. We also discuss biological structures that are not employed for protective purposes but provide flexibility and have damage tolerant properties suitable for developing strong, tough and lightweight bioinspired armour. Mobility and protection strategies have been considered to enhance the development of bio-inspired designs. Moreover, we discuss how additive manufacturing can be incorporated in the biomimicry design process.

[en] Highlights: • Artificial intelligent skin has been developed by combining color-tunability and memory into a single light-emitting device. • Color-tunable behaviors are correlated so that past light-stimulation experiences can be remembered. • The devices have multiple responses to electrical and non-contact light stimulations. • The devices can easily change color over a wide range from red to green for better naked-eye perception. The ability to combine the color-tunability capability of natural organisms with a memory function in a single device is highly desired and holds promise for potential applications such as intelligent artificial skin and human-machine interfaces. In this work, we propose a universal strategy to realize color-tunable skin with the compound function of memory by ingeniously integrating a memristor interface into a flexible quantum-dot light-emitting device. The devices developed using this strategy have multiple responses to electrical and light stimulations and can easily change their color over a wide range from red to green. Moreover, these color-tunable devices can mimic the unique function of “once bitten, twice shy” to enhance self-protection, and their color tunability is consistent with the memory-forgetting curve proposed by psychologists.

[en] Current knowledge about cell-biomaterial interactions is often based on two-dimensional (2D) cell culture systems like protein-coated glass slides. However, such smooth surfaces cannot mimic the nanofibrous environment of the native extracellular matrix (ECM). It is therefore a major challenge to transfer the results from 2D surfaces to 3D protein scaffolds with biomimetic nanofiber architecture. To understand the influence of different protein topographies on the cell response we introduce a new process to fabricate binary collagen scaffolds of variable thickness with spatially controlled regions of nanofibrous and smooth topography. We used pH-induced self-assembly to prepare collagen nanofibers with diameters between 130 and 150 nm on glass surfaces, which were partly covered with a polymer mask. After cross-linking with glutaraldehyde, smooth collagen films were prepared on the remaining glass regions. Atomic force microscopy revealed a much lower surface roughness of smooth collagen compared to nanofibers. Subsequently, we studied the viability, morphology and migration of 3T3 fibroblasts on both collagen topographies. We found small, elongated fibroblasts with few, long filopodia on collagen nanofibers whereas large, flat fibroblasts with many short filopodia were observed on smooth collagen. Actin stress fibers on collagen nanofibers were substantially reduced in comparison to smooth collagen. Live cell tracking revealed that fibroblasts on thin nanofibrous collagen migrated faster than on smooth collagen. In summary, binary collagen scaffolds enabled us for the first time to study cell responses to topographical cues on a single protein scaffold. In future, it will be intriguing to transfer our patterning process to other proteins to study fundamental principles of topography-dependent cell recognition processes. (paper)

[en] Highlights: • Establishment of biomimetic mineralized matrix with controllable mechanic stiffness. • Exploration of relationship between stiffness and BMSCs spreading and differentiation in bone mimicking environment. • Stiffness regulates osteogenic differentiation through cytoskeleton mediated mechanical signaling transduction pathway. • Supplying a promising material platform for bone and for understanding the matrix mechanic cues on cell fate. Construction of biomimetic microenvironment is vital to understand the relationship between matrix mechanical cues and cell fate, as well as to explore potential tissue engineering scaffolds for clinical application. In this study, through the enzymatic mineralizable collagen hydrogel system, we established the biomimetic bone matrix which was capable of realizing mechanical regulation independent of mineralization by incorporation of phosphorylated molecules (vinylphosphonic acid, VAP). Then, based on the biomimetic mineralized matrix with same composition but significantly different mechanical stiffness, we further investigated the effect of matrix stiffness on osteogenic differentiation of bone marrow stromal cells (BMSCs). The results clearly demonstrated that biomimetic mineralized microenvironment with higher mechanical strength promoted osteogenic differentiation of BMSCs. Further mechanism analysis demonstrated that the mineralized hydrogel with higher stiffness promoted cytoskeletal assembly, which enhanced the expression and nuclear colocalization of YAP and RUNX2, thereby promoted the osteogenic differentiation of stem cells. This study supplies a promising material platform not only for bone tissue engineering but also for exploring the mechanism of biomimetic bone matrix mechanics on osteogenesis.