Open reduction and Kirschner wire fixation method using a cylindrical block of unidirectional porous β-tricalcium phosphate for tongue-shaped calcaneal fracture: Report of three cases

Background

The artificial bone grafts are performed on the defect after reduction of the calcaneal fracture. Generally, it is an artificial bone graft with an implant, and there are a few reports of an artificial bone graft without an implant.

Cases

We report three cases (42-year-old male, 67-year-old male, 21-year-old female) of a tongue-shaped calcaneal fracture treated using a cylindrical unidirectional porous β-tricalcium phosphate artificial bone (Affinos®, Kurare co Ltd., Hyougo, Japan) to surgically repair bone defects after reduction. The bone defect is often observed when fracture is reduced in calcaneal fracture. There were significant bone defects, which were then fixed using Affinos® (forming a cylindrical shape block; diameter 10 mm x height 20 mm) to support the bone fragment, an artificial β-tricalcium phosphate bone with a porosity of 57 % (pore size 25-300 μm), characterized by a novel unidirectional porous structure. Postoperative early rehabilitation started with partial load from 5 weeks after surgery and was full weight bearing at 9 weeks after surgery. There was no correction loss and good bone fusion was obtained. By 12 months postoperatively, patients were able to be walking without pain and absorption and bone fusion around the artificial bone were observed maintaining the morphology immediately after reduction. The result was a good clinical result of one excellent (92 points) and two good (81 and 84 points) 1 year after surgery in the postoperative AOFAS Ankle-Hindfoot Scale.

Conclusion

Affinos® has a frost-like structure, which endows it with good tissue invasive properties because of the capillary effect. Moreover, it has excellent osteoconduction capability. In these 3 cases, Affinos® showed good strength, affinity, absorption, and bone substitution in a tongue-shaped calcaneal fracture. Further prospective studies are required to confirm our findings.

Fluorescent Nanodiamond-Gold Hybrid Particles for Multimodal Optical and Electron Microscopy Cellular Imaging

There is a continuous demand for imaging probes offering excellent performance in various microscopy techniques for comprehensive investigations of cellular processes by more than one technique. Fluorescent nanodiamond-gold nanoparticles (FND-Au) constitute a new class of "all-in-one" hybrid particles providing unique features for multimodal cellular imaging including optical imaging, electron microscopy, and, and potentially even quantum sensing. Confocal and optical coherence microscopy of the FND-Au allow fast investigations inside living cells via emission, scattering, and photothermal imaging techniques because the FND emission is not quenched by AuNPs. In electron microscopy, transmission electron microscopy (TEM) and scanning transmission electron microscopy (STEM) analysis of FND-Au reveals greatly enhanced contrast due to the gold particles as well as an extraordinary flickering behavior in three-dimensional cellular environments originating from the nanodiamonds. The unique multimodal imaging characteristics of FND-Au enable detailed studies inside cells ranging from statistical distributions at the entire cellular level (micrometers) down to the tracking of individual particles in subcellular organelles (nanometers). Herein, the processes of endosomal membrane uptake and release of FNDs were elucidated for the first time by the imaging of individual FND-Au hybrid nanoparticles with single-particle resolution. Their convenient preparation, the availability of various surface groups, their flexible detection modalities, and their single-particle contrast in combination with the capability for endosomal penetration and low cytotoxicity make FND-Au unique candidates for multimodal optical-electronic imaging applications with great potential for emerging techniques, such as quantum sensing inside living cells.

Prevention of catheter infection using a biodegradable tissue adhesive composed of human serum albumin and disuccinimidyl tartrate

A new material was prepared to reduce catheter infection composed of a flocked silicone sheet (AmTiO2NP-F) with TiO2 nanoparticle–immobilized poly(ethylene terephthalate) fibers modified with surface amino groups. This system was used in conjunction with a tissue adhesive composed of disuccinimidyl tartrate and human serum albumin. At a fixed disuccinimidyl tartrate content of 0.2 mmol in human serum albumin solution, AmTiO2NP-F bonded well with collagen-based casing (a model material for skin), with bond strength increasing to a maximum of 38 w/v% human serum albumin. The adhesive bonded AmTiO2NP-F to subcutaneous tissue in mice, and infiltration of the tissue into the AmTiO2NP-F further increased the bond strength for long-term insertions. The material was degraded within 7 days of implantation, and tissue reaction was mild, while infection was completely prevented. These results indicate that the combined use of AmTiO2NP-F and disuccinimidyl tartrate-A for implanted catheters can significantly alleviate the associated risk of infection.

Enhanced bonding strength of hydrophobically modified gelatin films on wet blood vessels

The bonding behavior between hydrophobically modified alkaline-treated gelatin (hm-AlGltn) films and porcine blood vessels was evaluated under wet conditions. Hexanoyl (Hx: C₆), decanoyl (Dec: C₁₀), and stearyl (Ste: C₁₈) chlorides were introduced into the amino groups of AlGltn to obtain HxAlGltn, DecAlGltn, and SteAlGltn, respectively, with various modification percentages. The hm-AlGltn was fabricated into films and thermally crosslinked to obtain water-insoluble films (t-hm-AlGltn). The 42% modified t-HxAlGltn (t-42HxAlGltn) possessed higher wettability than the 38% modified t-DecAlGltn (t-38DecAlGltn) and the 44% modified t-SteAlGltn (t-44SteAlGltn) films, and the t-42HxAlGltn film showed a high bonding strength with the blood vessel compared with all the hm-AlGltn films. Histological observations indicated that t-42HxAlGltn and t-38DecAlGltn remained on the blood vessel even after the bonding strength measurements. From cell culture experiments, the t-42HxAlGltn films showed significant cell adhesion compared to other films. These findings indicate that the Hx group easily interpenetrated the surface of blood vessels and effectively enhanced the bonding strength between the films and the tissue.

In vitro evaluation of tissue adhesives composed of hydrophobically modified gelatins and disuccinimidyl tartrate

The effect of the hydrophobic group content in gelatin on the bonding strength of novel tissue-penetrating tissue adhesives was evaluated. The hydrophobic groups introduced into gelatin were the saturated hexanoyl, palmitoyl, and stearoyl groups, and the unsaturated oleoyl group. A collagen casing was employed as an adherend to model soft tissue for the in vitro determination of bonding strength of tissue adhesives composed of various hydrophobically modified gelatins and disuccinimidyl tartrate. The adhesive composed of stearoyl-modified gelatin (7.4% stearoyl; 10Ste) and disuccinimidyl tartrate showed the highest bonding strength. The bonding strength of the adhesives decreased as the degree of substitution of the hydrophobic groups increased. Cell culture experiments demonstrated that fluorescein isothiocyanate-labeled 10Ste was integrated onto the surface of smooth muscle cells and showed no cytotoxicity. These results suggest that 10Ste interacted with the hydrophobic domains of collagen casings, such as hydrophobic amino acid residues and cell membranes. Therefore, 10Ste-disuccinimidyl tartrate is a promising adhesive for use in aortic dissection.

Adhesive properties and biocompatibility of tissue adhesives composed of various hydrophobically modified gelatins and disuccinimidyl tartrate

Adhesives comprising hydrophobically modified gelatin and disuccinimidyl tartrate were prepared with the aim of developing novel tissue adhesives with tissue-penetrating capability and biocompatibility. The hydrophobic groups employed were hexanoyl (Hx; C6), palmitoyl (Pam; C16), stearoyl (Ste; C18), and oleoyl (Ole; C18 unsaturated) groups. The bonding strength of the resulting tissue adhesives against fresh arterial media increased with increasing chain length of the saturated hydrocarbon up to C18 (Ste) when the degree of substitution of hydrocarbons in the hydrophobically modified gelatin molecule was 10% (10Ste) with a fixed succinimidyl group:amino group ratio of 1:1. The 10Ole–disuccinimidyl tartrate adhesive showed slightly lower bonding strength compared with 10Ste–disuccinimidyl tartrate adhesive. In contrast, the use of hydrophobically modified gelatin with a high substitution ratio (50%) showed lower bonding strength compared with the original gelatin. The peeling strength of 10Ste–disuccinimidyl tartrate and 10Ole–disuccinimidyl tartrate adhesives was similar and high compared with other adhesives. Based on the quantitative determination of biocompatibility, using nuclear factor-kappa B/luciferase transgenic mice (BALB/C-Tg (NF-κB-RE-luc)-Xen), the level of inflammation associated with 10Ste–disuccinimidyl tartrate adhesive was quite low compared with commercial aldehyde-based adhesive. From these results, 10Ste–disuccinimidyl tartrate adhesive possesses excellent biocompatibility as well as high bonding/peeling strength and, therefore, has potential use in clinical applications.

Enhanced bonding strength of a novel tissue adhesive consisting of cholesteryl group-modified gelatin and disuccinimidyl tartarate

The bonding strength and biocompatibility of a novel tissue adhesive consisting of cholesteryl group-modified gelatin and disuccinimidyl tartarate was evaluated. The approach was based on hydrophobically-modified gelatin to enhance the penetration of an adhesive into tissue. Disuccinimidyl tartarate was used to cross-link the cholesteryl group-modified gelatin. The cholesteryl group-modified gelatin was prepared by partially converting the gelatin amino groups with cholesteryl chloroformate. The bonding strength was evaluated by mixing cholesteryl group-modified gelatin and unmodified gelatin with the fixed amino groups/active ester groups of disuccinimidyl tartarate. The bonding strength of the resulting tissue adhesive was 1.7 times greater than the commercial aldehyde-based adhesive. The level of inflammation transcription factor, nuclear factor-kappa B, of the new tissue adhesive was significantly lower compared to the aldehyde-based adhesive after subcutaneous implantation. These results indicate that hydrophobic groups, such as cholesteryl, enhance tissue penetration as well as increase the bonding strength of tissue adhesive without a negative effect on the biocompatibility.

Enhanced tissue penetration-induced high bonding strength of a novel tissue adhesive composed of cholesteryl group-modified gelatin and disuccinimidyl tartarate

The aim of this study was to evaluate the effect of cholesteryl group content on the bonding strength of a novel tissue adhesive composed of cholesteryl group-modified geletin (CholGltn) and disuccinimidyl tartarate (DST). The bonding strength of this tissue adhesive with fresh arterial media reached a maximum at a CholGltn content of 70% in the CholGltn/gelatin (Gltn) mixture, which then decreased with increasing CholGltn content with a fixed succinimidyl group:amino group ratio of 1:1. The maximum bonding strength obtained was 6-fold higher compared with that of the original Gltn. Furthermore, maximum peeling strength was also obtained at a CholGltn content of 70% in the CholGltn/Gltn mixture and at a similar succinimidyl group:amino group ratio. The highest peeling strength was 8-fold higher compared with Gltn and 6-fold higher compared with commercial aldehyde-based adhesive. After exposure of FITC-labeled Gltn or CholGltn to aortic smooth muscle cells (SMCs), which are abundant in arterial media, CholGltn integrated effectively with the surface of SMCs. This indicated that FITC-labeled CholGltn anchors into the cell membrane of SMCs. From these results, it was demonstrated that tissue adhesive composed of a CholGltn/Gltn mixture and DST showed improved penetration into arterial media compared with adhesive composed of Gltn and DST. This behavior supports the suggestion that the hydrophobic cholesteryl group in Gltn contributes to the enhanced bonding/peeling strength. This novel tissue adhesive may become a useful material in the clinical field for the treatment of aortic dissection.