One-Step Surface Functionalized Hydrophilic Polypropylene Meshes for Hernia Repair Using Bio-Inspired Polydopamine

Tissue engineered multifunctional chitosan-modified polypropylene hernia mesh loaded with bioactive phyto-extracts

Surface modified tissue engineered polypropylene / PP hernia meshes were fabricated by incorporating Bacterial cellulose / BC and chitosan / CS and phytochemical extracts. Under current practice, hernia and other traumatic injuries to the abdominal organs are clinically treated with surgical meshes. Often the foreign body reaction and infections result in relapse in patients which dictates additional reparative surgical procedures and pain. To improve the outcome of clinical restorative procedures new biomaterials with improved characteristics are required. The functionalized meshes were physically and chemically characterized using SEM, mechanical testing, FTIR and XRD. The antimicrobial activity was qualitatively and quantitatively tested using E. coli and S. aureus strains of bacteria. In vitro biocompatibility and wound healing effect of the modified meshes were performed using NIH3T3 fibroblast cell lines. Furthermore, tissue engineering potential of the meshes was evaluated using confocal fluorescent microscopy. In vivo implantation of the meshes was performed in male wistar rats for 21 days. Therefore, PP meshes with sustained drug delivery system augmented with anti-inflammatory and anti-microbial characteristics were developed. The coatings hereby not only increased the tensile strength of meshes but also prevented the modified meshes from causing infection. Current study resulted in CS-BC bioactive PP meshes loaded with phytochemicals which showed anti-inflammatory, antibacterial and wound healing potential. These meshes can be valuable to lessen the post-surgical complications of implanted PP mesh and thus reduce rejection and recurrence.

Polydopamine Blending Increases Human Cell Proliferation in Gelatin-Xanthan Gum 3D-Printed Hydrogel

BACKGROUND

Gelatin-xanthan gum (Gel-Xnt) hydrogel has been previously modified to improve its printability; now, to increase its ability for use as cell-laden 3D scaffolds (bioink), polydopamine (PDA), a biocompatible, antibacterial, adhesive, and antioxidant mussel-inspired biopolymer, has been added (1-3% v/v) to hydrogel.

METHODS

Control (CT) and PDA-blended hydrogels were used to print 1 cm2 grids. The hydrogels' printability, moisture, swelling, hydrolysis, and porosity were tested after glutaraldehyde (GTA) crosslinking, while biocompatibility was tested using primary human-derived skin fibroblasts and spontaneously immortalized human keratinocytes (HaCaT). Keratinocyte or fibroblast suspension (100 µL, 2.5 × 105 cells) was combined with an uncrosslinked CT and PDA blended hydrogel to fabricate cylinders (0.5 cm high, 1 cm wide). These cylinders were then cross-linked and incubated for 1, 3, 7, 14, and 21 days. The presence of cells within various hydrogels was assessed using optical microscopy.

RESULTS AND DISCUSSION

PDA blending did not modify the hydrogel printability or physiochemical characteristics, suggesting that PDA did not interfere with GTA crosslinking. On the other hand, PDA presence strongly accelerated and increased both fibroblast and keratinocyte growth inside. This effect seemed to be linked to the adhesive abilities of PDA, which improve cell adhesion and, in turn, proliferation.

CONCLUSIONS

The simple PDA blending method described could help in obtaining a new bioink for the development of innovative 3D-printed wound dressings.

Polydopamine-Functionalized Bacterial Cellulose as Hydrogel Scaffolds for Skin Tissue Engineering

Bacterial cellulose (BC) is a natural polysaccharide polymer hydrogel produced sustainably by the strain Gluconacetobacter hansenii under static conditions. Due to their biocompatibility, easy functionalization, and necessary physicochemical and mechanical properties, BC nanocomposites are attracting interest in therapeutic applications. In this study, we functionalized BC hydrogel with polydopamine (PDA) without toxic crosslinkers and used it in skin tissue engineering. The BC nanofibers in the hydrogel had a thickness of 77.8 ± 20.3 nm, and they could be used to produce hydrophilic, adhesive, and cytocompatible composite biomaterials for skin tissue engineering applications using PDA. Characterization techniques, namely Fourier-transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM), and Raman spectroscopy, were performed to investigate the formation of polydopamine on the BC nanofibers. The XRD peaks for BC occur at 2θ = 14.65°, 16.69°, and 22.39°, which correspond to the planes of (100), (010), and (110) of cellulose type Iα. Raman spectroscopy confirmed the formation of PDA, as indicated by the presence of bands corresponding to the vibration of aromatic rings and aliphatic C-C and C-O stretching at 1336 and 1567 cm-1, respectively. FTIR confirmed the presence of peaks corresponding to PDA and BC in the BC/PDA hydrogel scaffolds at 3673, 3348, 2900, and 1052 cm-1, indicating the successful interaction of PDA with BC nanofibers, which was further corroborated by the SEM images. The tensile strength, swelling ratio, degradation, and surface wettability characteristics of the composite BC biomaterials were also investigated. The BC/PDA hydrogels with PDA-functionalized BC nanofibers demonstrated excellent tensile strength and water-wetting ability while maintaining the stability of the BC fibers. The enhanced cytocompatibility of the BC/PDA hydrogels was studied using the PrestoBlue assay. Culturing murine NIH/3T3 fibroblasts on BC/PDA hydrogels showed higher metabolic activity and enhanced proliferation. Additionally, it improved cell viability when using BC/PDA hydrogels. Thus, these BC/PDA composite biomaterials can be used as biocompatible natural alternatives to synthetic substitutes for skin tissue engineering and wound-dressing applications.

Facile mussel-inspired polydopamine-coated 3D-printed bioreactors for continuous flow biocatalysis

Enantiopure alcohol production by a flow system of 3D-printed bioreactor with immobilized Geotrichum candidum acetophenone reductase (GcAPRD).

Polydopamine-Inspired Surface Modification of Polypropylene Hernia Mesh Devices via Cold Oxygen Plasma: Antibacterial and Drug Release Properties

Mesh infection is a major complication of hernia surgery after polypropylene (PP) mesh implantation. Modifying the PP mesh with antibacterial drugs is an effective way to reduce the chance of infection, but the hydrophobic characteristic of PP fibers has obstructed the drug adhesion. Therefore, to prepare antimicrobial PP mesh with a stable drug coating layer and to slow the drug release property during the hernia repair process has a great practical meaning. In this work, PP meshes were coated by bio-inspired polydopamine (PDA), which can load and release levofloxacin. PP meshes were activated with cold oxygen plasma and then plasma activated PP fibers were coated with PDA. The PDA coated meshes were further soaked in levofloxacin. The levofloxacin loaded PP meshes demonstrate excellent antimicrobial properties for 6 days and the drug release has lasted for at least 24 h. Moreover, a control PP mesh sample without plasma treatment was also prepared, after coating with PDA and loading levofloxacin. The antimicrobial property was sustained only for two days. The maximum inhibition zone of PDA coated meshes with and without plasma treatment was 12.5 and 9 mm, respectively. On all accounts, the modification strategy can facilely lead to long-term property of infection prevention.