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Three dimensional (3D) bioprinting using photocrosslinkable hydrogels has gained considerable attention due to its versatility in various applications, including tissue engineering and drug delivery. Egg White (EW) is an organic biomaterial with excellent potential in tissue engineering. It provides abundant proteins, along with biocompatibility, bioactivity, adjustable mechanical properties, and intrinsic antiviral and antibacterial features. Here, a photocrosslinkable hydrogel derived from EW is developed through methacryloyl modification, resulting in Egg White methacryloyl (EWMA). Upon exposure to UV light, synthesized EWMA becomes crosslinked, creating hydrogels with remarkable bioactivity. These hydrogels offer adjustable mechanical and physical properties compatible with most current bioprinters. The EWMA hydrogels closely resemble the native extracellular matrix (ECM) due to cell‐binding and matrix metalloproteinase‐responsive motifs inherent in EW. In addition, EWMA promotes cell growth and proliferation in 3D cultures. It facilitates endothelialization when investigated with human umbilical vein endothelial cells (HUVECs), making it an attractive replacement for engineering hemocompatible vascular grafts and biomedical implants. In summary, the EWMA matrix enables the biofabrication of various living constructs. This breakthrough enhances the development of physiologically relevant 3D in vitro models and opens many opportunities in regenerative medicine. [ABSTRACT FROM AUTHOR]

Polyvinylidene fluoride (PVDF) electrospun scaffolds have recently been developed for cardiac tissue engineering applications thanks to their piezoelectricity. However, PVDFs' hydrophobic nature requires modifications by incorporating natural polymers. In this study, we focussed on the hybrid electrospinning of PVDF and gelatine and the further introduction of graphene oxide nanoparticles to investigate either hydrophilicity or piezoelectricity enhancement and its impact on mouse embryonic cardiomyocytes. The results revealed a nanofibre diameter of 379 ± 73 nm for the PVDF/gelatine/graphene oxide (PVDF-GO-CG) platform, providing excellent tensile strength. Additionally, hydrophilicity was improved by gelatine and GO incorporation compared with pure PVDF. Cellular studies also showed an elongated morphology of cardiomyocytes, similar to the myocardial tissue, as well as high viability and non-toxicity in the PVDF-GO-CG scaffold according to the average survival rate. Furthermore, the expression of connexin 43 and troponin T genes underwent an increment of 41 and 35% in the PVDF-GO-CG compared with the PVDF-CG sample. This study proves the applicability of the PVDF-GO-CG scaffold as an alternative substrate for developing engineered cardiac tissues by providing an environment to re-establish their synchronised communications. [ABSTRACT FROM AUTHOR]

Iron oxide nanoparticles (Fe2O3-NPs) were synthesized using Oscillatoria limnetica extract as strong reducing and capping agents. The synthesized iron oxide nanoparticles IONPs were characterized by UV-visible spectroscopy, Fourier transform infrared (FTIR), X-ray diffractive analysis (XRD), scanning electron microscope (SEM), and Energy dispersive X-ray spectroscopy (EDX). IONPs synthesis was confirmed by UV-visible spectroscopy by observing the peak at 471 nm. Furthermore, different in vitro biological assays, which showed important therapeutic potentials, were performed. Antimicrobial assay of biosynthesized IONPs was performed against four different Gram-positive and Gram-negative bacterial strains. E. coli was found to be the least suspected strain (MIC: 35 µg/mL), and B. subtilis was found to be the most suspected strain (MIC: 14 µg/mL). The maximum antifungal assay was observed for Aspergillus versicolor (MIC: 27 µg mL). The cytotoxic assay of IONPs was also studied using a brine shrimp cytotoxicity assay, and LD50 value was reported as 47 µg/mL. In toxicological evaluation, IONPs was found to be biologically compatible to human RBCs (IC50: >200 µg/mL). The antioxidant assay, DPPH 2,2-diphenyl-1-picrylhydrazyly was recorded at 73% for IONPs. In conclusion, IONPs revealed great biological potential and can be further recommended for in vitro and in vivo therapeutic purposes. [ABSTRACT FROM AUTHOR]

Microneedles (MNs) have been developed as minimally invasive tools for diagnostic and therapeutic applications. However, in recent years, there has been an increasing interest in developing smart multifunctional MN devices to provide automated and closed‐loop systems for body fluid extraction, biosensing, and drug delivery in a stimuli‐responsive manner. Although this technology is still in its infancy and far from being translated into the clinic, preclinical trials have shown some promise for the broad applications of multifunctional MN devices. The main challenge facing the fabrication of smart MN patches is the integration of multiple modules, such as drug carriers, highly sensitive biosensors, and data analyzers in one miniaturized MN device. Researchers have shown the feasibility of creating smart MNs by integrating stimuli‐responsive biomaterials and advanced microscale technologies, such as microsensors and microfluidic systems, to precisely control the transportation of biofluids and drugs throughout the system. These multifunctional MN devices can be envisioned in two distinct strategies. The first type includes individual drug delivery and biosensing MN units with a microfluidic system and a digital analyzer responsible for fluid transportation and communication between these two modules. The second type relies on smart biomaterials that can function as drug deliverers and biosensors by releasing drugs in a stimuli‐responsive manner. These smart biomaterials can undergo structural changes when exposed to external stimuli, such as pH and ionic changes, mimicking the biological systems. Studies have demonstrated a high potential of hydrogel‐based MN devices for a wide variety of biomedical applications, such as drug and cell delivery, as well as interstitial fluid extraction. Biodegradable hydrogels have also been advantageous for fabricating multifunctional MNs due to their high loading capacity and biocompatibility with the drug of choice. Here, we first review a set of MN devices that can be employed either for biosensing or delivery of multiple target molecules and compare them to the conventional and more simple systems, which are mainly designed for single‐molecule sensing or delivery. Subsequently, we expand our insight into advanced MN systems with multiple competencies, such as body fluid extraction, biosensing, and drug delivery at the point of care. The improvement of biomaterials knowledge and biofabrication techniques will allow us to efficiently tune the next generation of smart MNs and provide a realistic platform for more effective personalized therapeutics. [ABSTRACT FROM AUTHOR]

The crosstalk between osteoblasts and endothelial cells is critical for bone vascularization and regeneration. Here, we used a coaxial 3D bioprinting method to directly print an osteon‐like structure by depositing angiogenic and osteogenic bioinks from the core and shell regions of the coaxial nozzle, respectively. The bioinks were made up of gelatin, gelatin methacryloyl (GelMA), alginate, and hydroxyapatite (HAp) nanoparticles and were loaded with human umbilical vascular endothelial cells (HUVECs) and osteoblasts (MC3T3) in the core and shell regions, respectively. Conventional monoaxial 3D bioprinting was used as a control method, where the hydrogels, HAp nanoparticles, MC3T3 cells, and HUVECs were all mixed in one bioink and printed from the core nozzle. As a result, the bioprinted scaffolds were composed of cell‐laden fibers with either a core‐shell or homogenous structure, providing a non‐contact (indirect) or contact (direct) co‐culture of MC3T3 cells and HUVECs, respectively. Both structures supported the 3D culture of HUVECs and osteoblasts over a long period. The scaffolds also supported the expression of osteogenic and angiogenic factors. However, the gene expression was significantly higher for the core‐shell structure than the homogeneous structure due to the well‐defined distribution of osteoblasts and endothelial cells and the formation of vessel‐like structures in the co‐culture system. Our results indicated that the coaxial bioprinting technique, with the ability to create a non‐contact co‐culture of cells, can provide a more efficient bioprinting strategy for printing highly vascularized and bioactive bone structures. [ABSTRACT FROM AUTHOR]

The integration of robotic systems into bioprinters can facilitate the construction of high-resolution and complex tissue structures via digitally controlled robotic arms equipped with different types of printheads.17 Each of the printing components can be individually employed to fabricate different parts of tissue constructs, which can subsequently be assembled to create multi-functional heterogeneous structures. Three-dimensional (3D) bioprinting is an emerging additive manufacturing technique that has shown potential for fabricating complex biologically active constructs by exerting control over the positioning of cells and biomaterials using computer-aided systems. Harvesting cells from their native environments and manipulating them using bioprinters can expose cells to high levels of stress and change their gene-expression profiles.1 In addition, some cells may die or migrate out of the bioprinted constructs after implantation. Also, the inclusion of stimuli-responsive and AI components in bioinks can control the in vivo functionality of bioprinted tissues after implantation and pave the way toward constructing biomimetic and functional tissue constructs. [Extracted from the article]

[Display omitted] • Biofilm tolerance to antibiotics has led to the search for new alternatives. • Polysaccharide nanoparticles can be extracted from corn. • Cationized polysaccharide nanoparticles strongly interact with bacterial cells. • Cationized polysaccharide nanoparticles can inhibit biofilm formation. • Polysaccharide nanoparticles provide an environment-friendly strategy for treating biofilm formation. Biofilm tolerance to antibiotics has led to the search for new alternatives in treating biofilms. The use of metallic nanoparticles has been a suggested strategy against biofilms, but their potential environmental toxicity and high cost of synthesizing have limited their applications. In this study, we investigate the potential of polysaccharidic phytoglycogen nanoparticles extracted from corn, in treating cyanobacterial biofilms, which are the source of toxins and pollution in aquatic environments. Our results revealed that the surface of cyanobacterial cells was dominated by the negatively charged functional groups such as carboxylic and phosphoric groups. The native phytoglycogen (PhX) nanoparticles were dominated with non-charged groups, such as hydroxyl groups, and the cationized phytoglycogen (PhXC) nanoparticles showed positively charged surfaces due to the presence of quaternary ammonium cations. Our results indicated that, as opposed to PhX, PhXC strongly inhibited biofilm formation when dispersed in the culture medium. PhXC also eradicated the already grown cyanobacterial biofilms. The antibiofilm properties of PhXC were attributed to its strong electrostatic interactions with the cyanobacterial cells, which could inhibit cell/cell and cell/substrate interactions and nutrient exchange with the media. This class of antibacterial polysaccharide nanoparticles may provide a novel cost-effective and environment-friendly strategy for treating biofilm formation by a broad spectrum of bacteria. [ABSTRACT FROM AUTHOR]

Polyvinylidene fluoride (PVDF) electrospun scaffolds have recently been developed for cardiac tissue engineering applications thanks to their piezoelectricity. However, PVDFs' hydrophobic nature requires modifications by incorporating natural polymers. In this study, we focussed on the hybrid electrospinning of PVDF and gelatine and the further introduction of graphene oxide nanoparticles to investigate either hydrophilicity or piezoelectricity enhancement and its impact on mouse embryonic cardiomyocytes. The results revealed a nanofibre diameter of 379 ± 73 nm for the PVDF/gelatine/graphene oxide (PVDF-GO-CG) platform, providing excellent tensile strength. Additionally, hydrophilicity was improved by gelatine and GO incorporation compared with pure PVDF. Cellular studies also showed an elongated morphology of cardiomyocytes, similar to the myocardial tissue, as well as high viability and non-toxicity in the PVDF-GO-CG scaffold according to the average survival rate. Furthermore, the expression of connexin 43 and troponin T genes underwent an increment of 41 and 35% in the PVDF-GO-CG compared with the PVDF-CG sample. This study proves the applicability of the PVDF-GO-CG scaffold as an alternative substrate for developing engineered cardiac tissues by providing an environment to re-establish their synchronised communications.

Blood loss by hemorrhaging wounds accounts for over one-third of ∼5 million trauma fatalities worldwide every year. If not controlled in a timely manner, exsanguination can take lives within a few minutes. Developing new biomaterials that are easy to use by non-expert patients and promote rapid blood coagulation is an unmet medical need. Here, biocompatible, and biodegradable microneedle arrays (MNAs) based on gelatin methacryloyl (GelMA) biomaterial hybridized with silicate nanoplatelets (SNs) are developed for hemorrhage control. The SNs render the MNAs hemostatic, while the needle-shaped structure increases the contact area with blood, synergistically accelerating the clotting time from 11.5 min to 1.3 min in vitro . The engineered MNAs reduce bleeding by ∼92% compared with the untreated injury group in a rat liver bleeding model. SN-containing MNAs outperform the hemostatic effect of needle-free patches and a commercial hemostat in vivo via combining micro- and nanoengineered features. Furthermore, the tissue adhesive properties and mechanical interlocking support the suitability of MNAs for wound closure applications. These hemostatic MNAs may enable rapid hemorrhage control, particularly for patients in developing countries or remote areas with limited or no immediate access to hospitals., Competing Interests: The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (© 2022 The Authors.)

Tissue reconstruction requires the utilization of multiple biomaterials and cell types to replicate the delicate and complex structure of native tissues. Various three-dimensional (3D) bioprinting techniques have been developed to fabricate customized tissue structures; however, there are still significant challenges, such as vascularization, mechanical stability of printed constructs, and fabrication of gradient structures to be addressed for the creation of biomimetic and complex tissue constructs. One approach to address these challenges is to develop multimaterial 3D bioprinting techniques that can integrate various types of biomaterials and bioprinting capabilities towards the fabrication of more complex structures. Notable examples include multi-nozzle, coaxial, and microfluidics-assisted multimaterial 3D bioprinting techniques. More advanced multimaterial 3D printing techniques are emerging, and new areas in this niche technology are rapidly evolving. In this review, we briefly introduce the basics of individual 3D bioprinting techniques and then discuss the multimaterial 3D printing techniques that can be developed based on combination of these techniques for the engineering of complex and biomimetic tissue constructs. We also discuss the perspectives and future directions to develop state-of-the-art multimaterial 3D bioprinting techniques for engineering tissues and organs., (© 2021 IOP Publishing Ltd.)