Journal of biomedical materials research. Part B, Applied biomaterials最新文献

Urethral stricture is the narrowing of the urethra caused by the growth of aberrant tissue after an injury. Actual post-operative treatment requires the placement of a Foley catheter for external urinary drainage after surgery. However, it requires a second intervention for removal, and the contact with the external environment and non-biodegradable composition even aggravates urinary tract infections (UTIs) in 7.12% of patients. Thus, we developed a completely biodegradable intraurethral device (BID) as an alternative to catheterization. BID is a continuous-walled hollow tubular stent with outer wall corrugations composed of poly(d,l-lactide-co-ε-caprolactone) copolymer synthesized by ring-opening polymerization, using a bismuth-based catalyst. Complying with EU Medical Device Regulation 2017/745, BID was manufactured by injection molding following ISO 13485 and irradiated by e-beam, according to ISO 11137 and 11737. Physico-chemical characterization was evaluated following ISO 10993, showing a scalable synthetic procedure with reproducible composition, high molecular weight, adequate thermal properties, and metal content below its cytotoxic level. Scanning electron microscopic analysis confirmed consistent dimensions and no detrimental effect in the device after irradiation. Additionally, hydrolytic degradation studies (static and dynamic) showed complete degradation of BID after 90 days, obtained by the tailored composition of the synthesized copolymer and aligned with the tissue regeneration process. Mechanical properties confirmed a consistent tubular shape up to 28 days and no migration of the device even at a maximum urine flow of 1500 mL/min thanks to the tailored corrugated design of BID. These findings position BID as a promising alternative in post-operative urethral stricture management, addressing critical limitations of current practices. Hopefully, our BID might provide a biodegradable solution, minimizing UTIs and migration, and eliminating the current second intervention for catheter removal.

Periprosthetic joint infection (PJI) is a devastating complication of total joint arthroplasty, often necessitating two-stage revision surgery with antibiotic-loaded bone cement (ALBC) spacers, which cannot maintain therapeutic local antibiotic concentrations over time. This study evaluated the long-term stability, antimicrobial efficacy, and biocompatibility of an alternative material, submicron gentamicin sulfate-loaded ultrahigh molecular weight polyethylene (SM-GS/UHMWPE), in vitro and in vivo by using a subcutaneous rat model. SM-GS/UHMWPE implants containing 6 wt% and 10 wt% gentamicin sulfate (GS) were fabricated and tested in vitro and simultaneously in vivo by subcutaneous implantation in rats for 4, 8, and 26 weeks. Gentamicin stability was assessed using nuclear magnetic resonance (NMR) spectroscopy and liquid chromatography-mass spectrometry (LC–MS/MS). Antimicrobial efficacy against Staphylococcus aureus was determined via bacterial culture assays. Mechanical integrity was evaluated using tensile testing in vitro. Systemic toxicity was assessed through liver and kidney function markers, and histological analysis of kidney and skin tissues was performed. NMR and LC–MS/MS confirmed that gentamicin remained chemically stable over 26 weeks in vivo and in vitro. Antimicrobial testing showed sustained bacterial inhibition, with implants containing 10% GS achieving a 3.5-log reduction in bacterial counts for 6 months. Mechanical testing demonstrated minimal changes in tensile properties over time. Serum biochemical markers remained within normal ranges, and histological evaluation showed no significant inflammation or tissue damage. Gentamicin elution profiles indicated sustained release, maintaining intraarticular levels above 100 times the minimum inhibitory concentration (MIC) of S. aureus for 6 months. SM-GS/UHMWPE implants demonstrated prolonged antibiotic release while maintaining mechanical integrity, antimicrobial efficacy, and biocompatibility. These findings support the potential use of SM-GS/UHMWPE as a next-generation antibiotic-eluting spacer for PJI treatment, offering an alternative to ALBC for sustained drug release and reduced systemic toxicity risks.

Poly(ε-caprolactone) (PCL) is a biodegradable polyester known for its low melting point and high flexibility, making it ideal for various medical device applications. In this study, we introduce a conductive nanocarbon black-blended PCL as a reinforced ink for fabricating flexible and degradable piezoresistive bioelectrodes. This approach enables the creation of a piezoresistive bioelectrode optimized for precise biomechanical sensing. The bioelectrode exhibits exceptional mechanoelectrical stability under high tension (> 350%), repeated drawing (> 40%, 100 cycles), long-term bending (> 7000 cycles), extrusion (> 10,000 cycles), and torsion (> 90°). When assembled into flexible piezoresistive sensors, the sensor achieves a high sensitivity (2.66 kPa⁻¹ in the range of 0–3 kPa), along with excellent repeatability and durability (10,000 cycles at 5 N). The sensor has promising applications in human health monitoring, including finger, wrist, and elbow activity tracking, as well as knee joint space sensing for guiding precise surgical operations.

Chronic wounds, often complicated by microbial growth and insufficient regeneration, pose a significant challenge. To address these issues, we developed a hydrogel dressing made from natural polymers, tragacanth gum (TG) and chitosan (CS), incorporated synthesized copper oxide nanoparticles (CuO NPs) to promote wound healing and inhibit microorganisms at the wound site. We synthesized CuO NPs using a reduction method with pomegranate peel extract and analyzed their characteristics. The TG/CS hydrogel was then prepared and loaded with the synthesized NPs, followed by relevant physicochemical analysis. The hydrogel's degradation rate and antibacterial activity were determined, and its effects on cell migration and viability in skin fibroblasts were evaluated using suitable methods. The synthesized CuO NPs showed nanometer dimensions (about 30–50 nm) with a consistent spherical morphology, and compositional analysis confirmed the presence of their constituent elements. The TG/CS hydrogel incorporating CuO NPs displayed a smooth and uniform appearance with a porous structure featuring interconnected micrometer-sized pores. Infrared spectroscopy confirmed the functional groups of the hydrogel components and the presence of the NPs. Moreover, this hydrogel demonstrated high liquid absorption, porosity, and stable degradation over several days. It significantly inhibited the growth of both Gram-positive and Gram-negative bacteria. The hydrogel containing 10 wt% CuO NPs stimulated fibroblast cell growth and, most importantly, accelerated wound healing by inducing cell migration and filling the scratch gap within 48 h. Overall, the natural TG/CS hydrogel containing CuO NPs has a high potential to expedite wound healing as a multifunctional wound dressing.

Tissue engineering is a new alternative for the recovery from bone injuries. Nanomaterials are often combined with scaffolds to improve structure, bioactivity, stability, adhesion, and compatibility. Carbon dots (CDs), which are fluorescent carbon nanomaterials with diameters of less than 10 nm, are powerful allies. In this study, we aimed to develop chitosan-gelatin/hydroxyapatite scaffolds and CDs for use in bone tissue engineering. First, we developed two types of CDs based on gelatin and heat-treated them at 200°C for 3 h (CDA) or 4 h (CDB). Both systems were characterized, and CDA exhibited better quantum yield and cytotoxic behavior. Therefore, we selected CDA for the scaffolds. Scaffolds without (CG/HA) and with CDA (CG/HA/CDA) displayed suitable porosities and degradation rates. Based on in vitro tests, we observed that the CD-containing scaffolds presented an excellent cell adhesion rate (94–100%), an indirect cytotoxicity viability of approximately 75%, and a direct cytotoxicity viability of at least 100% at all analyzed times (p < 0.05). Furthermore, alkaline phosphatase (ALP) expression suggested the formation of more mature osteoblasts in CG/HA/CDA. Its association with CDA promotes bioactivity, stability, cell adhesion, and compatibility. We also highlighted the ability of CG/HA/CDA to emit fluorescence for monitoring cell growth during tissue regeneration. These results demonstrated that CDA is highly biocompatible and supports cell growth, which can induce bone tissue regeneration and help treat bone diseases.

Preventing bacterial infections on Ti-based medical products is crucial, driving the need for durable antibacterial surfaces with enhanced mechanical strength and photocatalytic activity. This study introduces an anodization process for fabricating a hard barrier-type TiO₂ layer on a Ti substrate with visible-light-responsive photocatalytic activity. The core technology involves using an electrolyte comprising nitrate and ethylene glycol maintained at a high temperature to improve the layer hardness and photocatalytic performance. The layer characteristics, including thickness, crystallinity, and density, sensitively varied with increasing electrolyte temperature. For instance, raising the temperature to 100°C increased the layer thickness and density. By contrast, the thickness decreased beyond 100°C, leading to the deterioration of photocatalytic performance. Using ethylene glycol containing 100 mM nitrate maintained around 100°C was appropriate for maximizing layer hardness and photocatalytic performance. The resulting monolithic TiO₂ layer exhibited a hardness of ~450 HV, approximately twice that of the Ti substrate. Moreover, it effectively reduced the number of living Escherichia coli to ~4/100 under ultraviolet (UV) light and ~4/10 under visible light after 4 h of illumination. These results provide a guideline for obtaining a semi-permanent antibacterial medium through anodization.