ACS Biomaterials Science & Engineering最新文献

Diamond-like carbon (DLC) wear debris, which is often composed of different types of structures, is generated from DLC-modified artificial joints in the human body, and its biocompatibility evaluation is especially important to prevent wear-debris-induced implant failure. Here, RAW 264.7 macrophages (inflammatory-reaction assay) and primary mouse osteoblasts (osteoblastogenesis assay) were employed to investigate the toxicity of DLC wear particles (DWPs) by evaluation of cell viability and morphology, enzyme-linked immunosorbent assays, and quantitative reverse-transcription polymerase chain reaction (PCR). Relevant histopathological analysis of rat joints was also performed in vivo. We found that DWPs with a relatively high sp²/sp³ ratio (graphite-phase tendency) manifested a higher cytotoxicity and significant inhibition of osteoblastogenesis. DWPs with a relatively low sp²/sp³ ratio (diamond-phase tendency) showed good biocompatibility in vivo. The DWPs exhibiting a low sp2/sp3 ratio demonstrated reduced secretion of TNF-α and IL-6, along with increased secretion of TIMP-1, resulting in the downregulation of MMP-2 and MMP-9 and upregulation of interleukin-10 (IL-10), thereby attenuating the inflammatory response. Moreover, coculturing osteoblasts with DWPs exhibiting a low sp²/sp³ ratio resulted in an elevated OPG/RANKL ratio and increased expression of OPG mRNA. Because of the absence of electrostatic repulsion, DWPs with a relatively low sp²/sp³ ratio enhanced bovine serum albumin adsorption, which favored cellular activities. Cytotoxicity assessment of DWPs can help establish an evaluation system for particle-related joint disease and can facilitate the clinical application of DLC-coated prostheses.

In bone tissue engineering, biological scaffolds are designed with structural and functional properties that closely resemble the extracellular environment, aiming to establish a microenvironment conducive to osteogenesis. Macrophages hold significant potential for promoting osteogenesis and modulating the biological behavior of tumor cells. Multiple coculture experiments of macrophages and osteoblasts have demonstrated that macrophage polarization significantly impacts osteogenesis. Therefore, exploring bone biomaterials that can modulate macrophage polarization holds great clinical significance. In this study, heparin was modified with maleimide and was used as a raw material to form a hydrogel with 4-am-PEG-SH. The compound was used to polarize macrophages and promote osteogenesis after combining with interleukin 4 (IL-4) by taking advantage of the electronegativity of heparin. The results revealed overexpressed M2 macrophage-related phenotypic genes and cocultivation with MC3T3-E1 cells demonstrated the osteogenesis-promoting effect of the loaded IL-4 heparin hydrogel. Previous research reported that hydrogel loaded with IL-4 can be used as a biomaterial for osteogenesis promotion. Heparin materials used in this paper are derived from clinically anticoagulant drugs and feature a simple operation. The synthesized hydrogel effectively binds cytokines, regulates macrophages to induce osteogenesis and has many potential clinical applications.

Chondrosarcoma (CHS), also known as malignant cartilage tumors, is the second most common bone cancer after osteosarcoma. This tumor is particularly chemo- and radioresistant, and the only therapeutic alternative is surgery with wide margins. The tumor immune microenvironment reveals an infiltration of tumor-associated macrophages (TAMs) sometimes approaching 50% of the tumor mass, mainly differentiated into M2-like phenotype and correlated with poor prognosis and metastasis. Thus, macrophage-targeting therapies could have an interest in the management of CHS. To evaluate these strategies, we propose here the development of a three-dimensional (3D) tumoroid co-culture model between two human CHS cell lines (JJ012 and CH2879) and a human leukemia monocytic cell line (THP-1) in a methylcellulose matrix. These two models were compared to the in vivo xenograft models in terms of macrophage phenotypes, proteoglycans, MMP-9, and COX-2 expression. Finally, mifamurtide, an immunomodulator acting on TAMs, was evaluated on the most in vitro relevant model: 3D co-culture CH2879 model. Our results showed that it is now possible to develop 3D models that very accurately mimic what is found in vivo with the possibility of evaluating treatments specific to a tumor cell component.

Drug delivery advances rely on using nano- and microsized carriers to transfer therapeutic molecules, although challenges persist in increasing the availability of new and even approved pharmaceutical products. Particle shape, a critical determinant in how these carriers distribute within the body after administration, raises opportunities of using, for instance, micrometer-sized nonspherical particles for vascular targeting and thereby creating new prospects for precise drug delivery to specific targeted areas. The versatility of polycrystalline silicon microfabrication allows for significant variation in the size and shape of microchips, and so, in the current work, photolithography was employed to create differently shaped polysilicon microchips, including cuboids, cubes, bars, and cylinders, to explore the influence of particle shape on cellular interactions. These microchips with different shapes and lateral dimensions, accounting for surface areas in the range of ca. 15 to 120 μm² and corresponding total volumes of 0.4 to 27 μm³, serve as ideal models for investigating their interactions with macrophages with diameters of ca. 20 μm. Side-scattering imaging flow cytometry was employed for studying the interaction of label-free prepared microchips with RAW 264.7 macrophages. Using a dose of 3 microchips per cell, results show that cuboids exhibit the highest cellular association (ca. 25%) and uptake (ca. 20%), suggesting their potential as efficient carriers for targeted drug delivery to macrophages. Conversely, similarly sized cylinders and bar-shaped microchips exhibit lower uptakes of about 8% and about 6%, respectively, indicating potential benefits in evading macrophage recognition. On average, 1-1.5 microchips were internalized, and ca. 1 microchip was surface-bound per cell, with cuboids showing the higher values overall. Macrophages respond to microchips by increasing their metabolic activity and releasing low levels of intracellular enzymes, indicating reduced toxicity. Interestingly, increasing the particle dose enhances macrophage metabolic activity without significantly affecting enzyme release.

In osteoarthritis (OA), degradation of cartilage pericellular matrix (PCM), the proteoglycan-rich immediate cell microniche, is a leading event of disease initiation. This study demonstrated that biomimetic proteoglycans (BPGs) can diffuse into human cartilage from both normal and osteoarthritic donors and are preferentially localized within the PCM. Applying immunofluorescence (IF)-guided AFM nanomechanical mapping, we show that this localization of BPGs increases the PCM micromodulus of both normal and OA specimens. These results illustrate the capability of BPGs to integrate with degenerative tissues and support the translational potential of BPGs for treating human OA and other diseases associated with proteoglycan degradation.

Analysis of biomarkers in living cells is crucial for deciphering the dynamics of cells as well as for precise diagnosis of diseases. DNA biosensors employ DNA sequences as probes to offer insights into living cells, and drive progress in disease diagnosis and drug development. In this review, we present recent advances in DNA biosensors for detecting biomarkers in living cells. The basic structural components of DNA biosensors and the signal output method are presented. The strategies of DNA biosensors crossing the cell membrane are also described, including coincubation, nanocarriers, and nanoelectroporation techniques. Based on biomarker categorization, we detail recent applications of DNA biosensors for detecting small molecules, RNAs, proteins, and integrated targets in living cells. Furthermore, the future development directions of DNA biosensors are summarized to encourage further research in this growing field.

The increasing cost of high-volume cultures and dependence on serum and growth factor supplementation limit the affordability of mesenchymal stromal cell (MSC) therapies. This has spurred interest in developing strategies that support adherent cell expansion while reducing raw material costs. Culture surfaces coated with sulfated glycosaminoglycans (GAGs), specifically heparan sulfate (HS), are an alternative to prolong growth factor retention in cell cultures. Unlike heparin, recombinant HS (rHS) offers strong binding affinity for multiple growth factors and extracellular matrix components, such as collagen I, without undesirable anticoagulant effects or xenobiotic health risks. The potential of rHS as a factor reservoir in MSC cultures remains underexplored. This study investigated the impact of rHS on the growth and anti-inflammatory properties of undifferentiated bone marrow MSCs in both planar and microcarrier-based cultures. It was hypothesized that rHS would enable MSC growth with minimal growth factor supplementation in a sulfation level-dependent manner. Cell culture surfaces were assembled via the layer-by-layer (LbL) method, combining alternating collagen I (COL) and rHS. These bilayers support cell adhesion and enable the incorporation of distinct sulfation levels on the culture surface. Examination of pro-mitogenic FGF and immunostimulatory IFN-γ release dynamics confirmed prolonged availability and sulfate level dependencies. Sulfated surfaces supported cell growth in low serum (2% FBS) and serum-free (SF) media at levels equivalent to standard culture conditions. Cell growth on rHS-coated surfaces in SF was comparable to that on heparin-coated surfaces and commercial surface-coated microcarriers in low serum. These growth benefits were observed in both planar and microcarrier (μCs) cultures. Additionally, rHS surfaces reduced β-galactosidase expression relative to uncoated surfaces, delaying cell senescence. Multivariate analysis of cytokines in conditioned media indicated that rHS-containing surfaces enhanced cytokine levels relative to uncoated surfaces during IFN-γ stimulation and correlated with decreased pro-inflammatory macrophage activity. Overall, utilizing highly sulfated rHS with COL reduces the need for exogenous growth factors and effectively supports MSC growth and anti-inflammatory potency on planar and microcarrier surfaces under minimal factor supplementation.

Statins are among the most widely used drugs for the inhibition of cholesterol biosynthesis, prevention of cardiovascular diseases, and treatment of hypercholesterolemia. Additionally, statins also exhibit cholesterol-independent benefits in various diseases, including neuroprotective properties in Alzheimer's disease, anti-inflammatory effects in coronary artery disease, and antiproliferative activities in cancer, which likely result from the statins' interaction and alteration of lipid bilayers. However, the membrane-modulatory effects of statins and the mechanisms by which statins alter lipid bilayers remain poorly understood. In this work, we explore the membrane-modulating effects of statins on model lipid bilayers and live cells. Through the use of fluorescence lifetime imaging microscopy (FLIM) combined with viscosity-sensitive environmental probes, we demonstrate that hydrophobic, but not hydrophilic, statins are capable of changing the microviscosity and lipid order in model and live cell membranes. Furthermore, we show that hydrophobic simvastatin is capable of forming nanoscale cholesterol-rich domains and homogenizing the cholesterol concentrations in lipid bilayers. Our results provide a mechanistic framework for understanding the bimodal effects of simvastatin on the lipid order and the lateral organization of cholesterol in lipid bilayers. Finally, we demonstrate that simvastatin temporarily decreases the microviscosity of live cell plasma membranes, making them more permeable and increasing the level of intracellular chemotherapeutic drug accumulation.

Bladder tissue engineering offers significant potential for repairing defects resulting from congenital and acquired conditions. However, the effectiveness of engineered grafts is often constrained by insufficient vascularization and neural regeneration. This study utilized four primary biomaterials─gelatin methacryloyl (GelMA), chitin nanocrystals (ChiNC), titanium carbide (MXene), and adipose-derived stem cells (ADSC)─to formulate two types of bioinks, GCM0.2 and GCM0.2-ADSC, in specified proportions. These bioinks were 3D printed onto bladder acellular matrix (BAM) patches to create BAM-GCM0.2 and BAM-GCM0.2-ADSC patches. The BAM-GCM0.2-ADSC patches underwent electrical stimulation to yield GCM0.2-ADSC-ES bladder patches. Employed for the repair of rat bladder defects, these patches were evaluated against a Control group, which underwent partial cystectomy followed by direct suturing. Our findings indicate that the inclusion of ADSC and electrical stimulation significantly enhances the regeneration of rat bladder smooth muscle (from [24.052 ± 2.782] % to [57.380 ± 4.017] %), blood vessels (from [5.326 ± 0.703] % to [12.723 ± 1.440] %), and nerves (from [0.227 ± 0.017] % to [1.369 ± 0.218] %). This research underscores the superior bladder repair capabilities of the GCM0.2-ADSC-ES patch and opens new pathways for bladder defect repair.

Over the past few decades, poly(methyl methacrylate) (PMMA) based bone cement has been clinically used extensively in orthopedics for arthroplasty and kyphoplasty, due to its biocompatibility and excellent primary fixation to the host bone. In this focused review, we discuss the use of various fillers and secondary chemical moieties to improve the bioactivity and the physicochemical properties. The viscosity of the PMMA blend formulations and working time are crucial to achieving intimate contact with the osseous tissue, which is highly sensitive to organic or inorganic fillers. Hydroxyapatite as a reinforcement resulted in compromised mechanical properties of the modified cement. The possible mechanisms of the additive- or filler-dependent strengthening or weakening of the PMMA blend are critically reviewed. The addition of layered double hydroxides with surface functionalization appears to be a promising approach to enhance the bonding of filler with the PMMA matrix. Such an approach consequently improves the mechanical properties, owing to enhanced dispersion as well as contributions from crack bridging. Finally, the use of emerging alternatives, such as nanoparticles, and the use of natural biomolecules were highlighted to improve bioactivity and antibacterial properties.