Biofabrication of 3D adipose tissue via assembly of composite stem cell spheroids containing adipo-inductive dual-signal delivery nanofibers

Reconstruction of large 3D tissues based on assembly of micro-sized multi-cellular spheroids has gained attention in tissue engineering. However, formation of 3D adipose tissue from spheroids has been challenging due to the limited adhesion capability and restricted cell mobility of adipocytes in culture media. In this study, we addressed this problem by developing adipo-inductive nanofibers enabling dual delivery of indomethacin and insulin. These nanofibers were introduced into composite spheroids comprising human adipose-derived stem cells (hADSCs). This approach led to a significant enhancement in the formation of uniform lipid droplets, as evidenced by the significantly increased Oil red O-stained area in spheroids incorporating indomethacin and insulin dual delivery nanofibers (56.9 ± 4.6%) compared to the control (15.6 ± 3.5%) with significantly greater gene expression associated with adipogenesis (C/EBPA, PPARG, FABP4, and adiponectin) of hADSCs. Furthermore, we investigated the influence of culture media on the migration and merging of spheroids and observed significant decrease in migration and merging of spheroids in adipogenic differentiation media. Conversely, the presence of adipo-inductive nanofibers promoted spheroid fusion, allowing the formation of macroscopic 3D adipose tissue in the absence of adipogenic supplements while facilitating homogeneous adipogenesis of hADSCs. The approach described here holds promise for the generation of 3D adipose tissue constructs by scaffold-free assembly of stem cell spheroids with potential applications in clinical and organ models.

Application of Noggin-Coated Electrospun Scaffold in Corneal Wound Healing

Purpose

The objective of this study is to develop and characterize electrospun corneal bandage infused with Noggin protein and evaluate its therapeutic potential in the treatment of superficial nonhealing corneal ulceration.

Methods

Electrospun nanofibrous scaffolds were created with different blend ratios of polycaprolactone and gelatin and coated with different concentrations of Noggin protein. Morphologic, mechanical, degradation, and surface chemistry of the developed scaffold was assessed. Biocompatibility of the developed scaffold with corneal epithelial cells was evaluated by looking at cell viability, proliferation, and immunostaining. In vitro wound healing in the presence of Noggin-coated scaffold was evaluated by measuring wound closure rate after scratch.

Results

Uniform nanofibrous scaffolds coated with Noggin were constructed through optimization of electrospinning parameters and demonstrated mechanical properties better than or similar to commercially available contact lenses used in corneal wound healing. In the presence of Noggin-coated scaffold, corneal epithelial cells showed higher proliferation and wound-healing rate.

Conclusions

This Noggin-coated electrospun scaffold represents a step toward, expanding treatment options for patients with indolent corneal ulcers.

Translational Relevance

In this study, the feasibility of Noggin-coated electrospun scaffold as a therapeutic for indolent corneal ulcer was evaluated. This study also provides a better perspective for understanding electrospun scaffolds as a tunable platform to infuse topical therapeutics and use as a corneal bandage.

Electrospun Carbon Nanotube-Based Scaffolds Exhibit High Conductivity and Cytocompatibility for Tissue Engineering Applications

Carbon nanotubes (CNTs) are known for their excellent conductive properties. Here, we present two novel methods, "sandwich" (sCNT) and dual deposition (DD CNT), for incorporating CNTs into electrospun polycaprolactone (PCL) and gelatin scaffolds to increase their conductance. Based on CNT percentage, the DD CNT scaffolds contain significantly higher quantities of CNTs than the sCNT scaffolds. The inclusion of CNTs increased the electrical conductance of scaffolds from 0.0 ± 0.00 kS (non-CNT) to 0.54 ± 0.10 kS (sCNT) and 5.22 ± 0.49 kS (DD CNT) when measured parallel to CNT arrays and to 0.25 ± 0.003 kS (sCNT) and 2.85 ± 1.12 (DD CNT) when measured orthogonally to CNT arrays. The inclusion of CNTs increased fiber diameter and pore size, promoting cellular migration into the scaffolds. CNT inclusion also decreased the degradation rate and increased hydrophobicity of scaffolds. Additionally, CNT inclusion increased Young's modulus and failure load of scaffolds, increasing their mechanical robustness. Murine fibroblasts were maintained on the scaffolds for 30 days, demonstrating high cytocompatibility. The increased conductivity and high cytocompatibility of the CNT-incorporated scaffolds make them appropriate candidates for future use in cardiac and neural tissue engineering.

Applications of electrospun scaffolds with enlarged pores in tissue engineering

Despite electrospinning has multiple advantages over other methods such as creating materials with superfine fiber diameter, high specific surface area, and good mechanical properties, the pore diameter of scaffolds prepared...

Preparation of Lutein-Loaded PVA/Sodium Alginate Nanofibers and Investigation of Its Release Behavior

This investigation aims to study the characteristics and release properties of lutein-loaded polyvinyl alcohol/sodium alginate (PVA/SA) nanofibers prepared by electrospinning. In order to increase PVA/SA nanofibers' water-resistant ability for potential biomedical applications, the electrospun PVA/SA nanofibers were cross-linked with a mixture of glutaraldehyde and saturated boric acid solution at room temperature. The nanofibers were characterized using scanning electron microscopy (SEM) and X-ray diffractometer (XRD). Disintegration time and contact angle measurements testified the hydrophilicity change of the nanofibers before and after cross-linking. The lutein release from the nanofibers after cross-linking was measured by an ultraviolet absorption spectrophotometer, which showed sustained release up to 48 h and followed anomalous (non-Fickian) release mechanism as indicated by diffusion exponent value obtained from the Korsmeyer-Peppas equation. The results indicated that the prepared lutein-loaded PVA/SA nanofibers have great potential as a controlled release system.

Electrospun Nanofibers for Label-Free Sensor Applications

Electrospinning is a simple, low-cost and versatile method for fabricating submicron and nano size fibers. Due to their large surface area, high aspect ratio and porous structure, electrospun nanofibers can be employed in wide range of applications. Biomedical, environmental, protective clothing and sensors are just few. The latter has attracted a great deal of attention, because for biosensor application, nanofibers have several advantages over traditional sensors, including a high surface-to-volume ratio and ease of functionalization. This review provides a short overview of several electrospun nanofibers applications, with an emphasis on biosensor applications. With respect to this area, focus is placed on label-free sensors, pertaining to both recent advances and fundamental research. Here, label-free sensor properties of sensitivity, selectivity, and detection are critically evaluated. Current challenges in this area and prospective future work is also discussed.