This paper addresses the potential of self-made polyester-urethane filament as a candidate for Fused Filament Fabrication (FFF)-based 3D printing (3DP) in medical applications. Since the industry does not provide many ready-made solutions of medical-grade polyurethane filaments, we undertook research aimed at presenting the process of thermoplastic polyurethane (TPU) filament formation, detailed characteristics, and 3DP of specially designed elastic porous structures as candidates in cancellous tissue engineering. Additionally, we examined whether 3D printing affects the structure and thermal stability of the filament. According to the obtained results, the processing parameters leading to the formation of high-quality TPU filament (TPU_F) were captured. The results showed that TPU_F remains stable under the FFF 3DP conditions. The series of in vitro studies involving long- and short-term degradation (0.1 M phosphate-buffered saline (PBS); 5 M sodium hydroxide (NaOH)), cytotoxicity (ISO 10993:5) and bioactivity (simulated body fluid (SBF) incubation), showed that TPU printouts possessing degradability of long-term degradable tissue constructs, are biocompatible and susceptible to mineralization in terms of hydroxyapatite (HAp) formation during SBF exposure. The formation of HAp on the surface of the specially designed porous tissue structures (PTS) was confirmed by scanning electron microscope (SEM) and energy-dispersive X-ray spectroscopy (EDS) studies. The compression test of PTS showed that the samples were strengthened due to SBF exposure and deposited HAp on their surface. Moreover, the determined values of the tensile strength (~30 MPa), Young’s modulus (~0.2 GPa), and compression strength (~1.1 MPa) allowed pre-consideration of TPU_F for FFF 3DP of cancellous bone tissue structures.
The aim of the performed study was to fabricate an antibacterial and degradable scaffold that may be used in the field of skin regeneration. To reach the degradation criterion for the biocompatible polyurethane (PUR), obtained by using amorphous α,ω-dihydroxy(ethylene-butylene adipate) macrodiol (PEBA), was used and processed with so-called “fast-degradable” polymer polylactide (PLA) (5 or 10 wt %). To meet the antibacterial requirement obtained, hybrid PUR-PLA scaffolds (HPPS) were modified with ciprofloxacin (Cipro) (2 or 5 wt %) and the fluoroquinolone antibiotic inhibiting growth of bacteria, such as Pseudomonas aeruginosa, Escherichia coli, and Staphylococcus aureus, which are the main causes of wound infections. Performed studies showed that Cipro-modified HPPS, obtained by using 5% of PLA, possess suitable mechanical characteristics, morphology, degradation rates, and demanded antimicrobial properties to be further developed as potential scaffolds for skin tissue engineering.
This paper addresses the potential application of flexible thermoplastic polyurethane (TPU) and poly(lactic acid) (PLA) compositions as a material for the production of antibacterial wound dressings using the Fused Filament Fabrication (FFF) 3D printing method. On the market, there are medical-grade polyurethane filaments available, but few of them have properties required for the fabrication of wound dressings, such as flexibility and antibacterial effects. Thus, research aimed at the production, characterization and modification of filaments based on different TPU/PLA compositions was conducted. The combination of mechanical (tensile, hardness), structural (FTIR), microscopic (optical and SEM), degradation (2 M HCl, 5 M NaOH, and 0.1 M CoCl2 in 20% H2O2) and printability analysis allowed us to select the most promising composition for further antibacterial modification (COMP-7,5PLA). The thermal stability of the chosen antibiotic—amikacin—was tested using processing temperature and HPLC. Two routes were used for the antibacterial modification of the selected filament—post-processing modification (AMI-1) and modification during processing (AMI-2). The antibacterial activity and amikacin release profiles were studied. The postprocessing modification method turned out to be superior and suitable for wound dressing fabrication due to its proven antimicrobial activity against E. coli, P. fluorescens, S. aureus and S. epidermidis bacteria.
The skeleton is a crucial element of the motion system in the human body, whose main function is to support and protect the soft tissues. Furthermore, the elements of the skeleton act as a storage place for minerals and participate in the production of red blood cells. The bone tissue includes the craniomaxillofacial bones, ribs, and spine. There are abundant reports in the literature indicating that the amount of treatments related to bone fractures increases year by year. Nowadays, the regeneration of the bone tissue is performed by using autografts or allografts, but this treatment method possesses a few disadvantages. Therefore, new and promising methods of bone tissue regeneration are constantly being sought. They often include the implantation of tissue scaffolds, which exhibit proper mechanical and osteoconductive properties. In this paper, the preparation of polyurethane (PUR) scaffolds modified by gelatin as the reinforcing factor and hydroxyapatite as the bioactive agent was described. The unmodified and modified scaffolds were tested for their mechanical properties; morphological assessments using optical microscopy were also conducted, as was the ability for calcification using scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDX). Moreover, each type of scaffold was subjected to a degradation process in 5M NaOH and 2M HCl aqueous solutions. It was noticed that the best properties promoting the calcium phosphate deposition were obtained for scaffolds modified with 2% gelatin solution containing 5% of hydroxyapatite.
The aim of performed studies was to fabricate an antibacterial and degradable scaffold that may be used in the field of skin regeneration. To reach the degradation criterion the biocompatible polyurethane (PUR), obtained by using amorphous macrodiol α,ω-dihydroxy(ethylene-butylene adipate) macrodiol (PEBA), was used and processed with so-called “fast-degradable” polymer polylactide (PLA) (5 wt% or 10 wt%). To meet the antibacterial requirement obtained hybrid PUR-PLA scaffolds (HPPS) were modified with ciprofloxacin (Cipro) (2 wt% or 5 wt%), the fluoroquinolone antibiotic inhibiting growth of bacteria such as Pseudomonas aeruginosa, Escherichia Coli and Staphylococcus aureus, which are main cause of wound infections. Obtained unmodified and Cipro-modified HPPS were studied towards their chemical composition to detect presence or absence of characteristic functional groups of PUR, PLA and Cipro, and as well to indicate the participation of hydrogen bonds in the HPPS structure in dependence on PLA addition and ciprofloxacin modification. Mechanical properties were studied to determine the possible application of HPPS as a skin tissue scaffold. Scanning electron microscopy (SEM) was used to study morphology of unmodified and Cipro-modified HPPS and to performed elementary analysis by using energy-dispersive x-ray spectroscopy (EDX) of obtained materials. Finally, the microbiological tests were performed to indicate the antibacterial effect of Cipro-modified HPPS on S.aureus growth. Performed studies showed that Cipro-modified HPPS, obtained by using 5 % of PLA, possess suitable mechanical characteristic, morphology, degradation rate and demanded antimicrobial properties to be further developed as a potential scaffolds for skin tissue engineering.
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