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Hydroxyapatite (HAp)-coated bone implants are frequently used for orthopaedic or dental implants since they offer high biocompatibility and osteoconductivity. Yet, problems such as infections, e.g. periprosthetic joint infections, occur when implanting foreign material into the body. In this study, HAp coatings were produced via high-velocity suspension flame spraying (HVSFS). This method allows for the production of thin coatings. We investigated the effects of different gas parameters on the coating properties and on the biocompatibility, which was tested on the human osteosarcoma cell line MG63. Furthermore, Copper (Cu) was added to achieve antibacterial properties which were evaluated against standard microorganisms using the airborne assay. Three gas parameter groups (low, medium, and high) with different Cu additions (0 wt.%, 1 wt.% and 1.5 wt.%) were evaluated. Our findings show that porosity as well as hardness can be controlled through gas parameters. Furthermore, we showed that it is possible to add Cu through external injection. The Cu content in the coating as well as the release varies with different gas parameters. Both antibacterial efficacy as well as biocompatibility are affected by the Cu content. We could significantly reduce the amount of colony-forming units (CFU) in all coatings for E. coli, CFU for S. aureus was reduced by adding 1.5 wt.% of Cu to the coating. The biocompatibility testing showed a cytotoxicity threshold at a Cu-release of 14.3 mg/L in 120 hours. Based on our findings, we suggest medium gas parameters for HVSFS and the addition of 1 wt.% Cu to the coating. With these parameters, a reasonable antibacterial effect can be achieved while maintaining sufficient biocompatibility.

Bone tissue engineering aims to harness materials to develop functional bone tissue to heal ‘critical-sized’ bone defects. This study examined a robust, coated poly(caprolactone) trimethacrylate (PCL-TMA) 3D-printable scaffold designed to augment bone formation. Following optimisation of the coatings, three bioactive coatings were examined, i) elastin-like polypeptide (ELP), ii) poly(ethyl acrylate) (PEA), fibronectin (FN) and bone morphogenetic protein-2 (BMP-2) applied sequentially (PEA/FN/BMP-2) and iii) both ELP and PEA/FN/BMP-2 coatings applied concurrently. The scaffold material was robust and showed biodegradability. The coatings demonstrated a significant ( p  < 0.05) osteogenic response in vitro in alkaline phosphatase gene upregulation and alkaline phosphatase production. The PCL-TMA scaffold and coatings supported angiogenesis and displayed excellent biocompatibility following evaluation on the chorioallantoic membrane assay. No significant ( p  < 0.05) heterotopic bone formed on the scaffolds within a murine subcutaneous implantation model, compared to the positive control of BMP-2 loaded collagen sponge following examination by micro-computed tomography or histology. The current studies demonstrate a range of innovative coated scaffold constructs with in vitro efficacy and clearly illustrate the importance of an appropriate in vivo environment to validate in vitro functionality prior to scale up and preclinical application.

This paper presents the surface treatment results of titanium, veterinary bone wedges. The functional coating is composed of a porous oxide layer (formed by a plasma electrolytic oxidation process) and a polymer poly(sebacic anhydride) (PSBA) layer loaded with amoxicillin (formed by dip coatings). The coatings were porous and composed of Ca (4.16%-6.54%) and P (7.64%-9.89% determined by scanning electron microscopy with EDX) in the upper part of the implant. The titanium bone wedges were hydrophilic (54° water contact angle) and rough (surface area (Sa):1.16 μm) The surface tension determined using diiodomethane was 68.6 ± 2.0° for the anodized implant and was similar for hybrid coatings: 60.7 ± 2.2°. 12.87 ± 0.91 µg/mL of amoxicillin was released from the implants during the first 30 min after immersion in the phosphate-buffered saline (PBS) solution. This concentration was enough to inhibit the Staphylococcus aureus ATCC 25923, and Staphylococcus epidermidis ATCC12228 growth. The obtained inhibition zones were between 27.3 ± 2.1 mm–30.7 ± 0.6 mm when implant extract after 1 h or 4 h immersion in PBS was collected. Various implant biocompatibility analyses were performed under in vivo conditions, including pyrogen test (3 rabbits), intracutaneous reactivity (3 rabbits, 5 places by side), acute systemic toxicity (20 house mice), and local lymph node assay (LLNA) (20 house mice). The extracts from implants were collected in polar and non-polar solutions, and the tests were conducted according to ISO 10993 standards. The results from the in vivo tests showed, that the implant’s extracts are not toxic (mass body change below 5%), not sensitizing (SI < 1.6), and do not show the pyrogen effect (changes in the temperature 0.15ºC). The biocompatibility tests were performed in a certificated laboratory with a good laboratory practice certificate after all the necessary permissions.

Background Radiation-induced skin injury (RSI) is a common complication of radiation therapy, that severely reduces the quality of life of patients, and there is currently no gold standard for treatment. Placental mesenchymal stem cells (PMSCs) have emerged as a promising therapeutic approach due to their regenerative and anti-inflammatory properties, and biomaterials can serve as cell scaffolds to prolong cell survival time. This study is the first to evaluate the safety and efficacy of the a topical application of PMSCs-embedded alginate hydrogel (PMSCs gel) in cancer patients suffering from RSI. Materials and methods This study was a double-blind, randomized, placebo-controlled phase II clinical trial conducted at Yunnan Cancer Hospital (Chinese Clinical Trial Registry, Approval Number: ChiCTR2400094739) involving participants with grade II or higher radiation-induced skin injuries. The participants were randomly assigned to either the PMSCs gel treatment group or the placebo control group and treated topically for six consecutive days. The primary outcomes included skin injury grade, pain assessment and wound healing rate, whereas the secondary outcomes focused on biomarker changes and quality of life assessments. Statistical analyses were performed using intention-to-treat (ITT) principles. Results This study included 66 patients, 23 males, and 43 females, with a mean radiation-induced skin injury area of 779 mm 2 . Compared with the placebo control group, the PMSCs gel treatment group presented a faster overall recovery rate compared to the placebo control group, with statistically significant daily improvements from Day 1 to Day 6. Although there was no significant difference in the full healing rates between the groups, the PMSCs gel treatment significantly prevented further wound expansion from Day 2 to Day 6. Moreover, overall pain relief was greater in the PMSCs gel treatment group than in the control group. Conclusions Our study has demonstrated for the first time that PMSCs hydrogel have significant potential for accelerating the repair of radiation-induced skin damage and reducing skin pain. Trial registration This retrospectively registered Chinese Clinical Trial Registry identifier: ChiCTR2400094739 ( https://www.chictr.org.cn/bin/project/edit?pid=250420 ).

Titanium alloys, especially Ti Al V, are widely used in orthopedic and dental implants. Additive manufacturing has emerged as an innovative fabrication technique for titanium implants, gradually replacing traditional machining methods. A notable feature of additively manufactured medical devices is their considerable surface heterogeneity and roughness. Coating these materials to achieve physical and chemical uniformity is essential for enhancing biocompatibility. This study evaluates the combined effect of surface roughness (ranging from sub-micrometer to micrometer scale) and three nanometer-thick polyelectrolyte multilayer coatings on protein adsorption, as well as the adhesion and proliferation of normal human osteoblasts. The adhesion of human osteoblasts to various substrates (either uncoated or coated) was quantified using a lactate dehydrogenase assay and scanning electron microscopy. The surface density of adsorbed human serum albumin was analyzed by the Bradford assay. Application of polyelectrolyte multilayer coatings significantly increased the hydrophilicity of titanium substrates without altering their sub-micrometer and micrometer roughness or topography. The coatings rich in reactive amino groups were found to enhance the adsorption of human serum albumin and promote the adhesion of osteoblasts. The chemical composition of the surface, particularly the presence of free primary amino groups, significantly affects cellular behavior in machined, sand-blasted, and additively manufactured titanium materials, while the impact of surface roughness appears secondary. No correlation was observed between surface hydrophilicity and protein adsorption or cell attachment.

Background Infection is one of the main reasons for failure of orthopedic implants. Antibacterial coatings may prevent bacterial adhesion and biofilm formation, according to various preclinical studies. The aim of the present study is to report the first clinical trial on an antibiotic-loaded fast-resorbable hydrogel coating (Defensive Antibacterial Coating, DAC ® ) to prevent surgical site infection, in patients undergoing internal osteosynthesis for closed fractures. Materials and methods In this multicenter randomized controlled prospective study, a total of 256 patients in five European orthopedic centers who were scheduled to receive osteosynthesis for a closed fracture, were randomly assigned to receive antibiotic-loaded DAC or to a control group (without coating). Pre- and postoperative assessment of laboratory tests, wound healing, clinical scores and X-rays were performed at fixed time intervals. Results Overall, 253 patients were available with a mean follow-up of 18.1 ± 4.5 months (range 12–30). On average, wound healing, clinical scores, laboratory tests and radiographic findings did not show any significant difference between the two groups. Six surgical site infections (4.6%) were observed in the control group compared to none in the treated group ( P  < 0.03). No local or systemic side-effects related to the DAC hydrogel product were observed and no detectable interference with bone healing was noted. Conclusions The use of a fast-resorbable antibiotic-loaded hydrogel implant coating provides a reduced rate of post-surgical site infections after internal osteosynthesis for closed fractures, without any detectable adverse event or side-effects. Level of evidence 2.

Drug-coated balloon (DCB) technology was developed as an alternative treatment for obstructive coronary artery disease (CAD) and in-stent restenosis (ISR). Management of coronary ISR is clinically challenging and frequently encountered in practice. The Agent DCB uses an inactive excipient to effectively deliver a targeted, therapeutic dose of paclitaxel to the vessel wall. AGENT IDE is a prospective, multicenter, randomized controlled trial to evaluate superiority of the Agent DCB to balloon angioplasty in treating patients with ISR. A total of 480 patients with ISR of a previously treated lesion length <26 mm and reference vessel diameter >2.0 mm to ≤4.0 mm will be initially randomized. Subjects presenting with recent myocardial infarction (MI), complex lesions, or thrombus in the target vessel will be excluded. An adaptive group sequential design with one formal interim analysis for sample size re-estimation will be conducted, and the sample size may be increased to a maximum of 600 subjects. The primary endpoint is the rate of 12-month target lesion failure (TLF; composite of any ischemia-driven revascularization of the target lesion (TLR), target vessel related MI, or cardiac death) and will be tested for superiority in the test arm against the control. Functional status and general health-related quality of life will be measured by changes in the EQ-5D scores. Subjects will be followed for 5 years following the index procedure. This study will prospectively evaluate the safety and efficacy of Agent DCB in patients treated for coronary ISR.

Titanium alloy (Ti6Al4V) is one of the most prominent biomaterials for bone contact because of its ability to bear mechanical loading and resist corrosion. The success of Ti6Al4V implants depends on bone formation on the implant surface. Hence, implant coatings which promote adhesion, proliferation and differentiation of bone-forming cells are desirable. One coating strategy is by adsorption of biomacromolecules. In this study, Ti6Al4V substrates produced by additive manufacturing (AM) were coated with whey protein isolate (WPI) fibrils, obtained at pH 2, and heparin or tinzaparin (a low molecular weight heparin LMWH) in order to improve the proliferation and differentiation of bone-forming cells. WPI fibrils proved to be an excellent support for the growth of human bone marrow stromal cells (hBMSC). Indeed, WPI fibrils were resistant to sterilization and were stable during storage. This WPI-heparin-enriched coating, especially the LMWH, enhanced the differentiation of hBMSC by increasing tissue non-specific alkaline phosphatase (TNAP) activity. Finally, the coating increased the hydrophilicity of the material. The results confirmed that WPI fibrils are an excellent biomaterial which can be used for biomedical coatings, as they are easily modifiable and resistant to heat treatments. Indeed, the already known positive effect on osteogenic integration of WPI-only coated substrates has been further enhanced by a simple adsorption procedure.

Regeneration of critical bone defects requires the use of biomaterials. The incorporation of osteoinductive agents, such as bone morphogenetic proteins (BMPs), improves bone formation. This study aimed to compare the efficacy of rhBMP-2 in combination with different materials for bone regeneration in critical-sized rat calvarial defects. This was an experimental animal study using 30 rats. In each rat, two 5-mm critical-size defects were made in the calvaria (60 bone defects in total) using a trephine. All rats were randomized to one of the six groups: control (C), autograft + rhBMP-2 (A), absorbable collagen sponge + rhBMP-2 (ACS), β-tricalcium phosphate + rhBMP-2 (B-TCP), bovine xenograft + rhBMP-2 (B), and hydroxyapatite + rhBMP-2 (HA). The outcome was assessed after 4 and 8 weeks using histological description and the histological bone healing scale. Statistical analysis was performed using the Kruskal-Wallis and Mann–Whitney U tests, with a p-value set at 0.05. The average bone healing scores per group were as follows: C group, 12.5; A group, 26.5; ACS group, 18.8; B-TCP group, 26.2; HA group, 20.9; and B group, 20.9. The C group showed a significant difference between weeks 4 and 8 (p=0.032). Among the 4-week groups, the C group showed a significant difference compared to A (p=0.001), ACS (p=0.017), and B-TCP (p=0.005) groups. The 8-week experimental group did not show any significant differences between the groups. The 5-mm critical size defect in rat calvaria requires the use of bone biomaterials to heal at 4 and 8 weeks. rhBMP-2, as applied in this study, showed no difference in new bone formation when combined with bovine, B-TCP, or HA biomaterials.

Brain organoids are invaluable tools for pathophysiological studies or drug screening, but there are still challenges to overcome in making them more reproducible and relevant. Recent advances in three-dimensional (3D) bioprinting of human neural organoids is an emerging approach that may overcome the limitations of self-organized organoids. It requires the development of optimal hydrogels, and a wealth of research has improved our knowledge about biomaterials both in terms of their intrinsic properties and their relevance on 3D culture of brain cells and tissue. Although biomaterials are rarely biologically neutral, few articles have reviewed their roles on neural cells. We here review the current knowledge on unmodified biomaterials amenable to support 3D bioprinting of neural organoids with a particular interest in their impact on cell homeostasis. Alginate is a particularly suitable bioink base for cell encapsulation. Gelatine is a valuable helper agent for 3D bioprinting due to its viscosity. Collagen, fibrin, hyaluronic acid and laminin provide biological support to adhesion, motility, differentiation or synaptogenesis and optimize the 3D culture of neural cells. Optimization of specialized hydrogels to direct differentiation of stem cells together with an increased resolution in phenotype analysis will further extend the spectrum of possible bioprinted brain disease models.