Fabrication and Characterization of Zn Particle Incorporated Fibrous Scaffolds for Potential Application in Tissue Healing and Regeneration

Electrospun Polycaprolactone-Gelatin Fibrils Enabled 3D Hydrogel Microcapsules for Biomedical Applications

Microcapsules provide a microenvironment by improving the protection and delivery of cells and drugs to specific tissue areas, promoting cell integration and tissue regeneration. Effective microcapsules must not only be permeable for micronutrient diffusion but mechanically stable. Alginate hydrogel is one of the commonly used biomaterials for fabricating microcapsules due to its gel-forming ability and low toxicity. However, its mechanical instability, inertness, and excessive porosity have impeded its use. Embedding nanofibrils in the alginate hydrogel microcapsules improves their biological and mechanical properties. In this research, electrospun composite nanofibers of PCL-gelatin (PG) were first fabricated, characterized, and cryoground. The filtered and cryoground powder solution was mixed with the alginate solution and through electrospray, fabricated into microcapsules. Parameters such as flow rate, voltage, and hydrogel composition, which are critical in the electrostatic encapsulation process, were optimized. The microcapsules were further immersed in different solvent environments (DI water, complete media, and PBS), which were observed and compared for their morphology, size distribution, and mechanical stability properties. The average diameters of the PG nanofibers ranged between 0.2 and 2 μm, with an average porosity between 58 and 73%. The average size of the microcapsules varied between 300 and 900 μm, depending on the solvent environment. Overall, results showed an improved alginate 3D hydrogel network suitable for biomedical applications.

Enhanced Cell Proliferation, Migration, and Fibroblast Differentiation with Electrospun PCL-Zinc Scaffolds Coated with Fibroblast-Derived ECM

Despite tremendous improvement in the development of tissue-regenerating materials, a promising solution that provides an optimal environment remains to be accomplished. Here, we report a composite nanofiber biomaterial scaffold as a promising solution that closely mimics the extracellular matrix (ECM) to improve cell viability, proliferation, and migration. Initially, nanofiber composites of polycaprolactone (PCL) and zinc (Zn) metal were fabricated by using electrospinning. The resulting PCL-Zn (PZ) nanofibers effectively guided the growth of NIH3T3 fibroblasts for 7 days, forming a fibroblast cell sheet. The PZ fibers were decellularized to remove autologous and allogenic cellular antigens while leaving an intact ECM with structural and functional components. The resulting nanofiber PCL-Zn-ECM (PZE) showcased a natural ECM bonded to the surface, providing a bioactive element to the interconnected fibers. The reseeding of NIH3T3 fibroblasts demonstrated the scaffold's excellent capacity to direct and support cell proliferation. Furthermore, in vitro cytotoxicity analysis and morphological staining confer the scaffold's biocompatibility. The PZE scaffold presents a promising development in which these scaffolds can be further used for various regenerative medicine applications including wound healing.

Zein-Coated Zn Metal Particles-Incorporated Nanofibers: A Potent Fibrous Platform for Loading and Release of Zn Ions for Wound Healing Application

Metal particles incorporated into polymer matrices in various forms and geometries are attractive material platforms for promoting wound healing and preventing infections. However, the fate of these metal particles and their degraded products in the tissue environment are still unknown, as both can produce cytotoxic effects and promote unwanted wound reactions. In this study, we develop biodegradable fibrous biomaterials embedded with metal particles that have an immune activation functions. Initially, biodegradable zinc (Zn) nanoparticles were modified with zein (G), a protein derived from corn. The zein-coated zinc particles (Z-G) were then embedded in polycaprolactone (P) fibers at different weight ratios to create fibrous biomaterials via electrospinning, which were subsequently analyzed for potential wound healing applications. We performed multimodal evaluations of the fibrous scaffolds, examining physicochemical properties such as fiber morphology, mechanical strength, hydrophilicity, degradation, and release of zinc ions (Zn2+), as well as biological properties, including in vitro cell culture studies. We provide evidence that the integration of 2.4 wt % of Z-G particles in polycaprolactone (PCL) nanofibrous scaffolds improved its physicochemical and biological functions. The in vitro cellular response of the scaffolds was evaluated using a series of cytotoxicity assays and immunocytochemistry analyses with three different cell types: mouse-derived fibroblast cell lines (NIH/3T3), human dermal fibroblasts (HDFn), and human umbilical vein endothelial cells (HUVECs). The composite fibrous scaffold exhibited robust activation and proliferation of NIH/3T3 and HDFn cells, along with a significant angiogenic potential in HUVECs. Immunocytochemistry confirmed elevated expression of vimentin and α-smooth muscle actin (α-SMA), suggesting that NIH/3T3 and Haden cells were highly differentiated into myofibroblasts. Additionally, the increased expression of CD31 and VE-cadherin in HUVECs suggests that the scaffold supports tube formation, thereby enhancing neovascularization and promoting an effective immune response. Overall, our findings demonstrate the regenerative potential of the self-enhanced Zn hemostatic bioscaffolds, which deliver both Zn2+ ions and zein proteins to nourish cells. This capability not only modulates cellular activities but also contributes to tissue repair and remodeling, making the scaffolds suitable for wound repair and various bioengineering applications.

New Generation of Osteoinductive and Antimicrobial Polycaprolactone-Based Scaffolds in Bone Tissue Engineering: A Review

With respect to other fields, bone tissue engineering has significantly expanded in recent years, leading not only to relevant advances in biomedical applications but also to innovative perspectives. Polycaprolactone (PCL), produced in the beginning of the 1930s, is a biocompatible and biodegradable polymer. Due to its mechanical and physicochemical features, as well as being easily shapeable, PCL-based constructs can be produced with different shapes and degradation kinetics. Moreover, due to various development processes, PCL can be made as 3D scaffolds or fibres for bone tissue regeneration applications. This outstanding biopolymer is versatile because it can be modified by adding agents with antimicrobial properties, not only antibiotics/antifungals, but also metal ions or natural compounds. In addition, to ameliorate its osteoproliferative features, it can be blended with calcium phosphates. This review is an overview of the current state of our recent investigation into PCL modifications designed to impair microbial adhesive capability and, in parallel, to allow eukaryotic cell viability and integration, in comparison with previous reviews and excellent research papers. Our recent results demonstrated that the developed 3D constructs had a high interconnected porosity, and the addition of biphasic calcium phosphate improved human cell attachment and proliferation. The incorporation of alternative antimicrobials-for instance, silver and essential oils-at tuneable concentrations counteracted microbial growth and biofilm formation, without affecting eukaryotic cells' viability. Notably, this challenging research area needs the multidisciplinary work of material scientists, biologists, and orthopaedic surgeons to determine the most suitable modifications on biomaterials to design favourable 3D scaffolds based on PCL for the targeted healing of damaged bone tissue.

Bridging Nanomanufacturing and Artificial Intelligence-A Comprehensive Review

Nanomanufacturing and digital manufacturing (DM) are defining the forefront of the fourth industrial revolution-Industry 4.0-as enabling technologies for the processing of materials spanning several length scales. This review delineates the evolution of nanomaterials and nanomanufacturing in the digital age for applications in medicine, robotics, sensory technology, semiconductors, and consumer electronics. The incorporation of artificial intelligence (AI) tools to explore nanomaterial synthesis, optimize nanomanufacturing processes, and aid high-fidelity nanoscale characterization is discussed. This paper elaborates on different machine-learning and deep-learning algorithms for analyzing nanoscale images, designing nanomaterials, and nano quality assurance. The challenges associated with the application of machine- and deep-learning models to achieve robust and accurate predictions are outlined. The prospects of incorporating sophisticated AI algorithms such as reinforced learning, explainable artificial intelligence (XAI), big data analytics for material synthesis, manufacturing process innovation, and nanosystem integration are discussed.

3D Printing of Biodegradable Polymeric Microneedles for Transdermal Drug Delivery Applications

Microneedle (MN) technology is an optimal choice for the delivery of drugs via the transdermal route, with a minimally invasive procedure. MN applications are varied from drug delivery, cosmetics, tissue engineering, vaccine delivery, and disease diagnostics. The MN is a biomedical device that offers many advantages including but not limited to a painless experience, being time-effective, and real-time sensing. This research implements additive manufacturing (AM) technology to fabricate MN arrays for advanced therapeutic applications. Stereolithography (SLA) was used to fabricate six MN designs with three aspect ratios. The MN array included conical-shaped 100 needles (10 × 10 needle) in each array. The microneedles were characterized using optical and scanning electron microscopy to evaluate the dimensional accuracy. Further, mechanical and insertion tests were performed to analyze the mechanical strength and skin penetration capabilities of the polymeric MN. MNs with higher aspect ratios had higher deformation characteristics suitable for penetration to deeper levels beyond the stratum corneum. MNs with both 0.3 mm and 0.4 mm base diameters displayed consistent force-displacement behavior during a skin-equivalent penetration test. This research establishes guidelines for fabricating polymeric MN for high-accuracy and low-cost 3D printing.

The 3D Printing of Nanocomposites for Wearable Biosensors: Recent Advances, Challenges, and Prospects

Notably, 3D-printed flexible and wearable biosensors have immense potential to interact with the human body noninvasively for the real-time and continuous health monitoring of physiological parameters. This paper comprehensively reviews the progress in 3D-printed wearable biosensors. The review also explores the incorporation of nanocomposites in 3D printing for biosensors. A detailed analysis of various 3D printing processes for fabricating wearable biosensors is reported. Besides this, recent advances in various 3D-printed wearable biosensors platforms such as sweat sensors, glucose sensors, electrocardiography sensors, electroencephalography sensors, tactile sensors, wearable oximeters, tattoo sensors, and respiratory sensors are discussed. Furthermore, the challenges and prospects associated with 3D-printed wearable biosensors are presented. This review is an invaluable resource for engineers, researchers, and healthcare clinicians, providing insights into the advancements and capabilities of 3D printing in the wearable biosensor domain.