Novel Lipid Nanoparticles Stable and Efficient for mRNA Transfection to Antigen-Presenting Cells.

mRNA vaccines have emerged as a pivotal tool in combating COVID-19, offering an advanced approach to immunization. A key challenge with these vaccines is their need for extremely-low-temperature storage, which affects their stability and shelf life. Our research addresses this issue by enhancing the stability of mRNA vaccines through a novel cationic lipid, O,O'-dimyristyl-N-lysyl aspartate (DMKD). DMKD effectively binds with mRNA, improving vaccine stability. We also integrated phosphatidylserine (PS) into the formulation to boost immune response by promoting the uptake of these nanoparticles by immune cells. Our findings reveal that DMKD-PS nanoparticles maintain structural integrity under long-term refrigeration and effectively protect mRNA. When tested, these nanoparticles containing green fluorescent protein (GFP) mRNA outperformed other commercial lipid nanoparticles in protein expression, both in immune cells (RAW 264.7 mouse macrophage) and non-immune cells (CT26 mouse colorectal carcinoma cells). Importantly, in vivo studies show that DMKD-PS nanoparticles are safely eliminated from the body within 48 h. The results suggest that DMKD-PS nanoparticles present a promising alternative for mRNA vaccine delivery, enhancing both the stability and effectiveness of these vaccines.

Usefulness of Prosthesis Made of Antibiotic-Loaded Acrylic Cement as an Alternative Implant in Older Patients With Medical Problems and Periprosthetic Hip Infections: A 2- to 10-Year Follow-Up Study.

BACKGROUND: The purpose of this study was to compare the clinical outcomes after 2-stage revision with those following single-stage revision in patients who developed periprosthetic joint infection after primary hip arthroplasty. METHODS: Between January 2004 and January 2013, we retrospectively reviewed patients who developed periprosthetic joint infection after primary hip arthroplasty and who underwent surgery for placement of a prosthesis made of antibiotic-loaded acrylic cement (PROSTALAC). Patients were divided into 2 groups based on the stages of revision. Group A was made up of patients who had undergone 2-stage revision using PROSTALAC as an interim prosthesis. Group B was made up of patients who had been compelled to undergo single-stage revision using PROSTALAC as an alternative implant because of older age and/or medical problems. Clinical outcomes were evaluated using a visual analog scale to score pain by calculating the Harris Hip Score and by determining the patient's walking ability. RESULTS: There were 20 patients in group A and 19 patients in group B. The mean follow-up period after final surgery was 68.8 months (range, 24-114 months). The infection resolution rate after initial PROSTALAC placement was 92.3%, and the final resolution rate was 94.9%. The visual analog scale and Harris Hip Score of group A were significantly better than those of group B. However, no significant difference in walking ability was found between the 2 groups. CONCLUSION: Although the clinical outcomes in patients with PROSTALAC implants were not as good as those who underwent 2-stage revision, PROSTALAC can be a useful alternative implant in selected patients who are debilitated because of older age and/or who have critical medical problems.

Fabrication of atelocollagen-coated bioabsorbable suture and the evaluation of its regenerative efficacy in Achilles tendon healing using a rat experimental model.

Recently, the incidence of Achilles tendon ruptures (ATRs) has become more common, and repair surgery using a bioabsorbable suture is generally preferred, particularly in the case of healthy patients. Sutures composed of poly(lactic-co-glycolic acid) (PLGA) are commonly used in ATR surgeries. Nevertheless, owing to the inherent limitations of PLGA, novel bioabsorbable sutures that can accelerate Achilles tendon healing are sought. Recently, several studies have demonstrated the beneficial effects of atelocollagen on tendon healing. In this study, poly(3,4-dihydroxy-L-phenylalanine) (pDOPA), a hydrophilic biomimetic material, was used to modify the hydrophobic surface of a PLGA suture (Vicryl, VC) for the stable coating of atelocollagen on its surface. The main objective was to fabricate an atelocollagen-coated VC suture and evaluate its performance in the healing of Achilles tendon using a rat model of open repair for ATR. Structural analyses of the surface-modified suture indicated that the collagen was successfully coated on the VC/pDOPA suture. Postoperative in vivo biomechanical analysis, histological evaluation, ultrastructural/morphological analyses, and western blotting confirmed that the tendons in the VC/pDOPA/Col group exhibit superior healing than those in the VC and VC/pDOPA groups after 1 and 6 weeks following the surgery. The this study suggests that atelocollagen-coated PLGA/pDOPA sutures are preferable for future medical applications, especially in the repair of ATR.

Waste sludge derived adsorbents for arsenate removal from water.

Aqueous arsenate [As(V)] was removed using an aluminum-based adsorbent (ABA) and coal mine drainage sludge coated polyurethane (CMDS-PU) prepared using alum and coal mine sludge, respectively. Their As(V) removal efficiencies were compared with each other and granular ferric hydroxide (GFH). The mineralogy and surface chemistry of materials were determined using wavelength dispersive X-ray fluorescence (WD XRF) and Fourier transform infrared spectroscopy (FTIR), respectively. The angle-resolved X-ray photoelectron spectroscopy (AR-XPS) studies confirmed As(V) retention on the adsorbent surfaces. The adsorption kinetics data were fitted to pseudo second-order rate equation. The faster As(V) uptake kinetics of GFH and ABA (GFH > ABA > CMDS-PU) were attributed to their large pore volume and mesoporous nature. Langmuir adsorption capacities of 22, 31 and 10 mg/g, were achieved for GFH, ABA and CMDS-PU, respectively. As(V) adsorption on GFH, ABA and CMDS-PU was endothermic. GFH and ABA were efficient over a wide pH range (3-10). In column studies, GFH, ABA, and CMDS-PU successfully treated 23625, 842, and 158 bed volumes (BVs) and 2094, 6400, and 17 BVs of As(V)-contaminated water with 9.5 and 27 EBCT, respectively (at pH = 6.0, Asi = 600 µg/L). The GFH and ABA have a potential to be used at large-scale aqueous phase As(V) remediation.

Wiring microbial biofilms to the electrode by osmium redox polymer for the performance enhancement of microbial fuel cells.

An osmium redox polymer, PAA-PVI-[Os(4,4'-dimethyl-2,2'-bipyridine)2Cl]+/2+ that has been used in enzymatic fuel cells and microbial sensors, was applied for the first time to the anode of single-chamber microbial fuel cells with the mixed culture inoculum aiming at enhancing performance. Functioning as a molecular wire connecting the biofilm to the anode, power density increased from 1479 mW m(-2) without modification to 2355 mW m(-2) after modification of the anode. Evidence from cyclic voltammetry showed that the catalytic activity of an anodic biofilm was greatly enhanced in the presence of an osmium redox polymer, indicating that electrons were more efficiently transferred to the anode via co-immobilized osmium complex tethered to wiring polymer chains at the potential range of -0.3 V-+0.1 V (vs. SCE). The optimum amount of the redox polymer was determined to be 0.163 mg cm(-2).

Biofunctionalized ceramic with self-assembled networks of nanochannels.

Nature designs circulatory systems with hierarchically organized networks of gradually tapered channels ranging from micrometer to nanometer in diameter. In most hard tissues in biological systems, fluid, gases, nutrients and wastes are constantly exchanged through such networks. Here, we developed a biologically inspired, hierarchically organized structure in ceramic to achieve effective permeation with minimum void region, using fabrication methods that create a long-range, highly interconnected nanochannel system in a ceramic biomaterial. This design of a synthetic model-material was implemented through a novel pressurized sintering process formulated to induce a gradual tapering in channel diameter based on pressure-dependent polymer agglomeration. The resulting system allows long-range, efficient transport of fluid and nutrients into sites and interfaces that conventional fluid conduction cannot reach without external force. We demonstrate the ability of mammalian bone-forming cells placed at the distal transport termination of the nanochannel system to proliferate in a manner dependent solely upon the supply of media by the self-powering nanochannels. This approach mimics the significant contribution that nanochannel transport plays in maintaining living hard tissues by providing nutrient supply that facilitates cell growth and differentiation, and thereby makes the ceramic composite "alive".

Fabrication of biofunctional stents with endothelial progenitor cell specificity for vascular re-endothelialization.

Endothelial progenitor cells (EPCs) have been identified as a crucial factor for re-endothelialization after stenting, resulting in the prevention of stent thrombosis and neointimal hyperplasia. Because EPCs can be introduced by antibody-antigen interactions, the suitable choice of antibody and the biocompatible surface modification technology including antibody immobilization are essential for developing an EPC-capturing stent. In this study, we fabricated a biofunctional stent with EPC specificity by grafting a hydrophilic polymer and consecutively immobilizing the antibody against vascular endothelial cadherin (VE-cadherin) which is one of the specific EPC surface markers. The surface of a stainless steel stent was sequentially modified by acid-treatment, silanization and covalent attachment of polymers not only to improve biocompatibility but also to introduce functional groups on the stent surface. The surface-modified stent immobilized anti-VE-cadherin antibodies, and the EPCs were remarkably captured whereas THP-1s, human acute monocytic leukemia cells, were not adsorbed on the stent. Furthermore, we confirmed that the recruited EPCs developed the endothelial cell layers on the antibody-conjugated stent. These positive in vitro results will encourage the extensive application of biofunctional surface modification technology for a variety of medical devices.

Comparison of endothelialization and neointimal formation with stents coated with antibodies against CD34 and vascular endothelial-cadherin.

Vascular endothelial-cadherin (VE-cadherin) is exclusively expressed on the late endothelial progenitor cells (EPC). Therefore, VE-cadherin could be an ideal target surface molecule to capture circulating late EPC. In the present study, we evaluated whether anti-VE-cadherin antibody-coated stents (VE-cad stents) might accelerate endothelial recovery and reduce neointimal formation more than anti-CD34 antibody-coated stents (CD34 stents) through the superior ability to capture the late EPC. The stainless steel stents were coated with anti-human VE-cadherin antibodies or anti-human CD34 antibodies under the same condition. In vitro, VE-cad stents showed higher number of adhering EPC (823.6 ± 182.2 versus 379.2 ± 137.2 cells per HPF, p < 0.001). VE-cad stents also demonstrated better specific capturing of cells with endothelial lineage markers than CD34 stents did in flow cytometric analysis. VE-cad stents showed more effective re-endothelialization after 1 h, 24 h, and 3 days in vivo. At 42 days, VE-cad stents demonstrated significantly smaller neointima area (0.92 ± 0.38 versus 1.24 ± 0.41 mm(2), p = 0.002) and significantly lower PCNA positive cells in neointima (1684.8 ± 658.8/mm(2) versus 2681.7 ± 375.1/mm(2), p = 0.008), compared with CD34 stents. In conclusion, VE-cad stents captured EPC and endothelial cells more selectively in vitro, accelerated re-endothelialization over stents, and reduced neointimal formation in vivo, compared with CD34 stents.

The surface modification of stainless steel and the correlation between the surface properties and protein adsorption.

Protein adsorption on a biomaterial surface is of great importance as it usually induces unfavorable biological cascades, with the result that much surface modification research has had to be performed in an effort to prevent this. In this study, we developed surface modification methods for stainless steel, which is a representative metal for biomedical device. The stainless steels were first smoothened to different extents by electropolishing, in order to obtain a rough or smooth surface. On these two kinds of substrates, we introduced epoxide groups to the metal surface by silanization with 3-glycidoxypropyltrimethoxysilane (GPTS). Then, various polymers such as poly(ethylene glycol) (PEG), poly(tetrahydrofuran glycol) (PTG), poly(propylene glycol) (PPG) and poly(dimethylsiloxane) (PDMS) were grafted on the silanized stainless steels. Each surface modification step was confirmed by various analytical methods. Contact angle measurement revealed that the surface hydrophilicity was controllable by polymer grafting. Root-mean-square (RMS) data of atomic force microscopy showed that surface roughness was dramatically changed by electropolishing. Based on these results, the correlation between surface properties and protein adsorption was investigated. In the protein adsorption study, we observed that all of the polymer-grafted stainless steels exhibited lower protein adsorption, when compared with bare stainless steel. Moreover, a hydrophilic and smooth surface was found to be the best of choice for decreasing the protein adsorption.

Mechanical and chemical protection of a wired enzyme oxygen cathode by a cubic phase lyotropic liquid crystal.

When implanted in animals, enzyme-containing battery electrodes, biofuel cell electrodes, and biosensors are often damaged by components of the biological environment. An O2 cathode, superior to the classical platinum cathode, which would be implanted, as part of a caseless physiological pH miniature Zn-O2 battery or as part of a caseless and membraneless miniature glucose-O2 biofuel cell, is rapidly damaged by serum urate at its operating potential. The cathode is made by electrically connecting, or wiring, reaction centers of bilirubin oxidase to carbon with an electron-conducting redox hydrogel. In the physiological pH 7.3 electrolyte battery or biofuel cell, the O2 cathode should operate at, or positive of, 0.3 V (Ag/AgCl), where the urate anion, a common serum component, is electrooxidized. Because an unidentified urate electrooxidation intermediate, formed in the presence of O2, damages the wired bilirubin oxidase electrocatalyst, urate must be excluded from the cathode. Unlike O2, which permeates through both the lipid and the aqueous interconnected networks of cubic-phase lyotropic liquid crystals, urate permeates only through their continuous three-dimensional aqueous channel networks. The aqueous channels have well-defined diameters of approximately 5 nm in the monoolein/water cubic-phase liquid crystal. Through tailoring the wall charge of the aqueous channels, the anion/cation permeability ratio can be modulated. Thus, doping the monoolein of the monoolein/water liquid crystal with 1,2-dioleoyl-sn-glycero-3-phosphate makes the aqueous channel walls anionic and reduces the urate permeation in the liquid crystal. As a result, the ratio of the urate electrooxidation current to the O2 electroreduction current is reduced from 1:3 to 1:100 for 5-mm O2 cathodes rotating at 1000 rpm. Doping with 1,2-dioleoyl-sn-glycero-3-phosphate also increases the shear strength of the cubic-phase monoolein/water lyotropic liquid crystal. While the undoped liquid crystal is promptly damaged at the 0.1 N m-2 average shear stress generated by rotating the 5-mm-diameter disk cathode at 1000 rpm in a physiological aqueous solution, the 10 mol % 1,2-dioleoyl-sn-glycero-3-phosphate-doped film remains intact. The mechanical strengthening of the lyotropic liquid crystal by the two-tailed 1,2-dioleoyl-sn-glycero-3-phosphate is attributed to cross-linking hydrophobic bonds (i.e., bonds resulting of the increase in entropy upon the freeing of the translation and rotation of multiple water molecules), which is analogous to the strengthening of polymer-based plastic materials by cross-linking through covalent bonds.