3D Gel Research Articles

Reflected shear wave computed tomography for elasticity imaging of 3D cell cultures using a single-element transducer

Shear wave elasticity imaging (SWEI) has long been used to quantify tissue stiffness in clinical diagnoses. In comparison with conventional bulk-based measurement methods, SWEI offers the distinct advantage of nondestructive sampling, thereby enabling the spatiotemporal monitoring of stiffness variations. However, applying SWEI to assessing millimeter-scale three-dimensional (3D) cell environments has faced limitations despite its potential in mechanobiology, and the existing techniques are insufficient for imaging inhomogeneous media environments. In this study, we investigated a computed tomography technique specifically designed for reflected SWEI (called R-SWCT) by rotational scanning in a sample using a 20-MHz ultrasound single-element transducer. We focused on samples containing a single inclusion with higher stiffness than the surrounding medium, mimicking the situation of a tumor sphere embedded in a 3D gel. Our method reconstructs the stiffness distribution using a curve-fitting method, wherein coefficients of Gaussian curves are fitted to the wavefronts of simulated signals. This reconstruction method yielded coefficients that closely approximated the wavefronts obtained experimentally, with a maximum difference between the measured and predicted shear wave speeds of only 0.1 m/s for phantom samples and 0.2 m/s for cell samples. The system and methodologies proposed in this research have demonstrated the feasibility of employing R-SWCT to study the remodeling dynamics of a cell group within its surrounding matrix in an in vitro setting. This noninvasive method also facilitates an exploration of how irradiation dosage used in radiation therapy can induce temporal alterations in the shear wave speed in 3D cancer cell cultures.

Multi-layered Microfluidic Drug Screening Platform Enabling Simultaneous Generation of Linear and Logarithmic Concentration Gradients

Since many microfluidic devices have limited drug dose order of gradients and incorporate 2D cell culture, we here present a multi-layered platform with linear and logarithmic gradients with 3D-cell culturing chambers. By employing Hagen–Poiseuille flow resistance equation and the parallel electric schematics, we determined the appropriate channel dimensions to achieve the desired target concentrations (100%, 50%, 20%, 10%, 5%, 2%, 1%, 0%). To validate the gradient formation against theoretical values, we introduced a solution containing fluorescein into the microfluidic chip. Moreover, cell culturing chambers were spaced out laterally for every 9 mm, aligning with the dimensions with the standard plate reader, providing enhanced usability. Vertical layout of the chip minimized the lateral dimension required for housing various components while maintaining a favorable height for imaging. By preventing the need to use external tubing to connect concentration gradient generator and cell culturing chamber modules, our platform holds promise in facilitating the integration of microfluidics into drug evaluation processes. To demonstrate use of this flexible platform, we tested two chemotherapy drugs against human bladder cancer cells (T24) embedded in 3D fibrin gel and evaluated their cell viability and proliferation rate. IC50 values were extracted for cells exposed to varying doses of cisplatin, gemcitabine, and gemcitabine with a fixed cisplatin dose, confirming the enhanced apoptosis of the bladder cancer cells and the advantages of combination chemotherapy. This simple multi-layered device may accelerate screening of anti-cancer drugs for a specific cell type by extracting optimal dosage for two drugs.

Carboxymethyl chitosan and dialdehyde cellulose nanocrystal based injectable self-healing emulsion gel

The study aims to demonstrate a general method for producing emulsion gels with self-healing properties. Specifically, the self-healing emulsion gels were fabricated by crosslinking carboxymethyl chitosan (CMC) stabilized emulsion with dialdehyde cellulose nanocrystal (DACNC). The reversible imine bonds between primary amino groups from CMC and aldehyde groups from DACNC endow the emulsion gel with self-healing properties. The compressive strength of the emulsion gels was greatly increased from 37.43 kPa 83.7 kPa by encapsulating emulsion droplets (φ = 0 %–40 %.) in the gel matrix. Moreover, the emulsion gels exhibited much better self-healing and injectability ability compared to hydrogel because the emulsion droplets interacted with the 3D gel matrix, which were observed by cryo-SEM and CLSM. The emulsion droplets distributed in the gel matrix improved the mobility and interfacial contact area of CMC and DACNC. Water contact measurement confirmed that the CMC/DACNC self-healing emulsion gels showed a hydrophilic surface. The CMC/DACNC emulsion gels could maintain a good structural stability as the oil loss was <1 % after centrifugation. This research provides a method to keep the structural stability of emulsion gels by inducing self-healing ability and modified cellulose nanocrystals, which could extend the shelf life and application area of emulsion gels.

On the recycling of PVDF-reinforced graphite by using 3D gel printing

The recycling of polyvinylidene fluoride (PVDF) reinforced graphite through material extrusion (MEX) has been widely reported. But hitherto little has been reported on the recycling of PVDF-graphite composite using 3D gel printing. This study compares the sensing, dielectric, and mechanical properties of PVDF-reinforced graphite by 3D gel printing and the MEX (based on insertion loss (S21), return loss (S11), dielectric constant (εr), scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDS), differential scanning calorimeter (DSC), and X-ray diffraction (XRD) analysis). The study suggests that for recycled PVDF composite (with 50% graphite by wt.), 3D gel printing outsailed the MEX process as the peak load (PL), peak strength (PS), and εr were improved by 48.49%, 264%, and 65.37% respectively. As regards crystallinity (%) and Young’s modulus (E), a reduction of 13.11%, and 72.22% was noticed with 3D gel-printed components.

The impact of pressure-shift freezing on the three-dimensional network structure and properties of myofibrillar proteins in surimi gel derived from freshwater fish

Freezing treatment can prolong the shelf life of surimi products, but it will lead to deterioration of surimi gel quality. This study compared the effects of three different processing methods — non-freezing processing (control), conventional air freezing (CAF), and pressure-shift freezing (PSF) — on the three-dimensional (3D) network structure of grass carp surimi gel. After PSF treatment, the pores in the 3D gel network structure were denser compared to the control group which facilitates interaction of water and network structure. Furthermore, the ultraviolet and fluorescence spectral analysis indicated that PSF treatment mitigates the decline in stability of the tertiary structure of myofibrillar protein (MP) during freezing. The microstructure of MP showed that PSF treatment promotes the cross-linking of MP to form protein aggregates and then promotes the gelation of MP. Industrial relevancePSF can increase the commodity value of low-value freshwater fish products and has potential in the development of new products of surimi gels. This study reported a novel idea and theoretical basis for the application of PSF technology in the frozen food and aquatic product processing industry.

Clinical outcomes of self-glazed zirconia veneers produced by 3D gel deposition: a retrospective study

BackgroundSelf-glazed zirconia (SZ) restorations are made by a novel additive three-dimensional gel deposition approach, which are suitable for a straightforward completely digital workflow. SZ has recently been used as minimally invasive veneer, but its clinical outcomes have not been clarified yet. This study aimed to evaluate the preliminary clinical outcomes of SZ veneers compared with the widely used lithium disilicate glass–ceramic veneers made by either pressing (PG) or milling (MG) process.MethodsFifty-six patients treated with SZ, PG, and MG veneers by 2 specialists between June 2018 and October 2022 were identified. Patients were recalled for follow-up at least 1 year after restoration. Clinical outcomes were assessed by 2 independent evaluators according to the modified United States Public Health Service (USPHS) criteria. Overall patient satisfaction was assessed using visual analogue scale (VAS), and analyzed by one-way ANOVA. Chi-square test was applied to compare the difference in the success and survival rates among the 3 groups.ResultsA total of 51 patients restored with 45 SZ, 40 PG, and 41 MG veneers completed the study, with a patient dropout rate of 8.9%. Mean and standard deviation of follow-up period was 35.0 ± 14.7 months. All restorations performed well at baseline, except for 2 SZ veneers with mismatched color (rated Bravo). During follow-up, marginal discrepancy (rated Bravo) was found in 4 MG veneers and 1 PG veneer, and partially fractured (rated Charlie) was found in another 2 PG veneers. The survival rate of SZ, PG, and MG veneers was 100%, 95%, and 100%, with a success rate of 95.56%, 92.50%, and 90.24%, respectively, none of which were significantly different (p = 0.099 and 0.628, respectively). The mean VAS score of SZ, PG, and MG was 95.00 ± 1.57, 93.93 ± 2.40, and 94.89 ± 2.00 respectively, without significant difference (p > 0.05).ConclusionSZ veneers exhibited comparable preliminary clinical outcomes to PG and MG veneers, which could be considered as a feasible option for minimally invasive restorative treatment.

Gelation behaviour of Auricularia polytricha polysaccharides-whey protein isolate

The thermal gelling behaviour and formation mechanism of Auricularia polytricha polysaccharides-whey protein isolate (APP-WPI) gel was studied by moisture migration, conformation transformation and microstructure. Electrostatic repulsion between APP and WPI limited the rapid or random aggregation of WPI aggregate, leading to establishment of a more ordered structure. The conformation transformation from α-helix to β-sheet and strong hydrophobic interaction in WPI gelation process promoted the formation of stable three-dimension (3D) gel network, as proved by the increase in crystallinity and thermal stability. The composite gel had decreased T23 and PT23 values which indicated restricted water mobility within the gel resulting in dense water cavity via APP's high-water absorption. Furthermore, 0.25–1.00% APP concentration improved gel hardness, water holding capacity, storage modulus (G′) and loss modulus (G″) of WPI gel. This study demonstrated that APP played a vital role in regulating ideal physicochemical and structural characteristics of WPI-based gel products.

Dynamic light-responsive RhoA activity regulates mechanosensitive stem cell fate decision in 3D matrices

The behavior of stem cells is regulated by mechanical cues in their niche that continuously vary due to extracellular matrix (ECM) remodeling, pulsated mechanical stress exerted by blood flow, and/or cell migration. However, it is still unclear how dynamics of mechanical cues influence stem cell lineage commitment, especially in a 3D microenvironment where mechanosensing differs from that in a 2D microenvironment. In the present study, we investigated how temporally varying mechanical signaling regulates expression of the early growth response 1 gene (Egr1), which we recently discovered to be a 3D matrix-specific mediator of mechanosensitive neural stem cell (NSC) lineage commitment. Specifically, we temporally controlled the activity of Ras homolog family member A (RhoA), which is known to have a central role in mechanotransduction, using our previously developed Arabidopsis thaliana cryptochrome-2-based optoactivation system. Interestingly, pulsed RhoA activation induced Egr1 upregulation in stiff 3D gels only, whereas static light stimulation induced an increase in Egr1 expression across a wide range of 3D gel stiffnesses. Actin assembly inhibition limited Egr1 upregulation upon RhoA activation, implying that RhoA signaling requires an actin-involved process to upregulate Egr1. Consistently, static-light RhoA activation rather than pulsed-light activation restricted neurogenesis in soft gels. Our findings indicate that the dynamics of RhoA activation influence Egr1-mediated stem cell fate within 3D matrices in a matrix stiffness-dependent manner.

Abstract 1505: Unraveling diepafitaxis: Investigating ECM stiffness and microarchitecture in tumor spheroid migration

Abstract Background: Metastasis, accounting for up to 90% of cancer-related deaths, remains one of the least understood aspects of cancer progression. Recent research has shifted focus from solely biological hallmarks to the physical characteristics of cancer, such as the stiffness and microarchitecture of the extracellular matrix (ECM), which play pivotal roles in metastatic advancement. We previously introduced the concept of 'diepafitaxis' to describe a unique mechanism driving the interface-mediated tropism of tumor spheroids at matrix-surface boundaries. This phenomenon suggests that cancer cells preferentially migrate along a 2D 'interfacial' track formed by heterogeneous 3D ECM structures, facilitating invasion and dispersion. However, the exact mechanisms by which interfacial components, stiffness, and structural attributes influence cell movement remain debated. To investigate this, we have developed a microfluidic chip with a precisely controlled stiffness of the hydrogel matrix-matrix interface (MMI), aiming to shed light on specific diepafitatic behaviors. Method: We developed a polydimethylsiloxane (PDMS)-based microfluidic chip using a traditional photolithographic process. This chip features three channels, with the center channel designed to precisely control various MMI stiffness combinations: stiff vs soft (t-o), stiff vs stiff (t-t) and soft vs soft (o-o). MDA-MB-231 breast cancer spheroids (BCS), representing an in vitro tumor model, were embedded in the top gel. We observed the dynamic behavior of these cancer spheroids over a 24-h period using differential interference contrast (DIC) microscopy. Result: The study revealed that BCS exhibited more pronounced dispersion in a soft homogeneous ECM compared to a stiff ECM in 3D environments. Interestingly, when BCS were near an MMI, a stiffer MMI (t-t) significantly enhanced BCS invasiveness and single-cell migration, more so than t-o, and notably more than o-o. We previously described this phenomenon as '2.5D migration,' where cells migrate in a ventral 2D manner within a sandwiched 3D gel structure. This diepafitatic behavior was further analyzed for its response to gravitational effects and the influence of chemotaxis, induced by introducing VEGF on one side of the microfluidic channel. Conclusion: Conclusively, our study demonstrates that the stiffness and structure of the ECM, particularly at MMI, significantly influence the invasive behavior and migration patterns of BCS, underscoring the critical role of mechanical microenvironments in cancer metastasis. Citation Format: Hsiang-Pei Chen, Ya-Chu Tsai, Ting-Yuan Tu. Unraveling diepafitaxis: Investigating ECM stiffness and microarchitecture in tumor spheroid migration [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 1505.

3D Polymer Gel Dosimeters with iCBCT 3D Reading and polyGeVero-CT Software Package for Quality Assurance in Radiotherapy.

Dynamically evolving radiotherapy instruments require advancements in compatible 3D dosimetry systems. This paper reports on such tools for the coincidence test of the mechanical and radiation isocenter for a medical accelerator as part of the quality assurance in routine radiotherapy practice. Three-dimensional polymer gel dosimeters were used in combination with 3D reading by iterative cone beam computed tomography and 3D data processing using the polyGeVero-CT software package. Different polymer gel dosimeters were used with the following acronyms: VIP, PAGAT, MAGIC, and NIPAM. The same scheme was used for each dosimeter: (i) irradiation sensitivity test for the iterative cone beam computed tomography reading to determine the appropriate monitor unit for irradiation, and (ii) verification of the chosen irradiation conditions by a star-shot 2D irradiation of each 3D dosimeter in the direction of performing the test. This work concludes with the optimum monitor unit per beam for each selected 3D dosimeter, delivers schemes for quick and easy determination of the radiation isocenter and performing the coincidence test.

Mitochondrial metabolism sustains CD8+ T cell migration for an efficient infiltration into solid tumors

The ability of CD8+ T cells to infiltrate solid tumors and reach cancer cells is associated with improved patient survival and responses to immunotherapy. Thus, identifying the factors controlling T cell migration in tumors is critical, so that strategies to intervene on these targets can be developed. Although interstitial motility is a highly energy-demanding process, the metabolic requirements of CD8+ T cells migrating in a 3D environment remain unclear. Here, we demonstrate that the tricarboxylic acid (TCA) cycle is the main metabolic pathway sustaining human CD8+ T cell motility in 3D collagen gels and tumor slices while glycolysis plays a more minor role. Using pharmacological and genetic approaches, we report that CD8+ T cell migration depends on the mitochondrial oxidation of glucose and glutamine, but not fatty acids, and both ATP and ROS produced by mitochondria are required for T cells to migrate. Pharmacological interventions to increase mitochondrial activity improve CD8+ T cell intratumoral migration and CAR T cell recruitment into tumor islets leading to better control of tumor growth in human xenograft models. Our study highlights the rationale of targeting mitochondrial metabolism to enhance the migration and antitumor efficacy of CAR T cells in treating solid tumors.

Vascular System Inspired 3D Electrolyte Network for High Rate and High Mass Loading Graphene Supercapacitor

AbstractHigh charge rate and high mass loading ability are of practical importance for high power and high volumetric performance supercapacitors but are always challenged by tortuous and sluggish ion diffusion in thick electrodes. Here, inspired by the hepatic vascular system, hierarchical 3D electrolyte networks are proposed to facilitate ion diffusion across laminar graphene films, resulting in a 14‐fold improved ion diffusion coefficient, better rate ability, and high mass loading ability for graphene supercapacitors. Such design enables graphene electrodes with high capacitance up to 236 F g−1, packing densities of 0.67–0.78 g cm−3 depending on structures; and core stack with 10 mg cm−2 mass loading exhibits a high energy density of 45.4 Wh L−1, which is among the state‐of‐the‐art graphene supercapacitors. This study provides a comprehensive investigation of structure‐related capacitive properties, guiding electrode design for high‐rate and high‐mass‐loading graphene supercapacitors. Moreover, such design also benefits solid‐state graphene supercapacitors by forming 3D gel electrolyte structures, which enable higher capacitance and better mechanical robustness, showing potential for flexible energy storage.

Bio‐Inspired Camouflage Skin with Photonic Crystal Structure and Size‐Confinement Effect

AbstractCamouflage skin holds immense potential for a variety of advanced applications, such as artificial intelligence, soft robotics, and flexible/wearable electronics. Currently, most existing materials for constructing camouflage skin are mainly based on inorganic materials with an inverse opal scaffold, which significantly limits their further development because of the poor mechanical properties and environmental instability. Inspired by rana slvaticas, a new type of camouflage skin based on one‐dimentional (1D) photonic crystal (PC) gel is designed and synthesized, which combines the advantages of 1D PC structures with 3D flexible gels in a single skin device. Taking advantage of the unique structures, the resulting camouflage skins demonstrated attractive properties, including excellent mechanical performance, self‐adaptive camouflage capabilities, and long‐term stability in ambient conditions. Specifically, the camouflage skin can quickly recognize and match the background by modulating the optical signals of external stimuli. The synergistic effect of the glycerol, the dodecyl glycerol itaconate (DGI), and the nano‐space structures altogether contribute to the outstanding long‐term environmental stability of the camouflage skin. Overall, by combining the bio‐inspired concept and molecular engineering strategy, camouflage skin based on PC gels is synthesized, which greatly enriched the application and development in the smart skins field.

Self-Healing Hydrogel Containing Decellularized Liver Matrix and Endothelial Cell-Covered Hepatocyte Spheroids for Rescue of Injured Hepatocytes.

Liver fibrosis occurs in many chronic liver diseases, while severe fibrosis can lead to liver failure. A chitosan-phenol based self-healing hydrogel (CP) integrated with decellularized liver matrix (DLM) is proposed in this study as a 3D gel matrix to carry hepatocytes for possible therapy of liver fibrosis. To mimic the physiological liver microenvironment, DLM is extracted from pigs and mixed with CP hydrogel to generate DLM-CP self-healing hydrogel. Hepatocyte spheroids coated with endothelial cells (ECs) are fabricated using a customized method and embedded in the hydrogel. Hepatocytes injured by exposure to CCl4-containing medium are used as the in vitro toxin-mediated liver fibrosis model, where the EC-covered hepatocyte spheroids embedded in the hydrogel are co-cultured with the injured hepatocytes. The urea synthesis of the injured hepatocytes reaches 91% of the normal level after 7 days of co-culture, indicating that the hepatic function of injured hepatocytes is rescued by the hybrid spheroid-laden DLM-CP hydrogel. Moreover, the relative lactate dehydrogenase activity of the injured hepatocytes is decreased 49% by the hybrid spheroid-laden DLM-CP hydrogel after 7 days of co-culture, suggesting reduced damage in the injured hepatocytes. The combination of hepatocyte/EC hybrid spheroids and DLM-CP hydrogel presents a promising therapeutic strategy for hepatic fibrosis.

3D Traction Force Microscopy in Biological Gels: From Single Cells to Multicellular Spheroids.

Cell traction force plays a critical role in directing cellular functions, such as proliferation, migration, and differentiation. Current understanding of cell traction force is largely derived from 2D measurements where cells are plated on 2D substrates. However, 2D measurements do not recapitulate a vital aspect of living systems; that is, cells actively remodel their surrounding extracellular matrix (ECM), and the remodeled ECM, in return, can have a profound impact on cell phenotype and traction force generation. This reciprocal adaptivity of living systems is encoded in the material properties of biological gels. In this review, we summarize recent progress in measuring cell traction force for cells embedded within 3D biological gels, with an emphasis on cell-ECM cross talk. We also provide perspectives on tools and techniques that could be adapted to measure cell traction force in complex biochemical and biophysical environments.

Development and characterization of novel ultra-stable high internal phase Pickering emulsions gel: Interface structure, stabilization mechanism, and applications

While both protein-polysaccharide complexes and continuous phase gelation showed great potential for stabilizing high internal phase Pickering emulsions (HIPPEs), it is not known which strategies are more effective and adaptive. In this work, HIPPEs gel was prepared by Ca2+-induced continuous phase gelation of ovalbumin (OVA)-low methoxyl pectin (LMP) electrostatic complexes particles (OLECP)-stabilized HIPPEs. The microstructure, rheological properties, stability, and application of HIPPEs and HIPPEs gel were systematically investigated and compared at different LMP concentrations. The results showed that, compared to HIPPEs, continuous phase gelation effectively improved the viscoelasticity, water binding capacity, and hardness of HIPPEs gel due to its robust and developed interface architecture. CLSM and cryo-SEM observations revealed that OLECP interconnected with each other in the continuous phase to form an advanced network architecture in HIPPEs. Whereas, a firm gel network structure and a thick interfacial layer were found in HIPPEs gel. More importantly, with increasing pectin concentration, the cross-linking phenomenon of OLECP mainly at the interface, transformed into the gelation behavior of excess pectin molecules dominating in the continuous phase. LMP contributed to the formation of a finer 3D gel network structure and a firmer interfacial layer, providing a smaller oil droplet size and superior stability for HIPPEs gel. The photochemical stability of curcumin was increased from 16.1 ± 1.5 % to 93.7 ± 2.2 % after encapsulation in HIPPEs gel. In vitro digestion results testified that HIPPEs gel (10:15, w/w) can promote fat hydrolysis (from 32.35 ± 3.06 % to 45.52 ± 2.75 %) and enhance the bioaccessibility of curcumin (from 20.1 ± 1.5 % to 32.8 ± 2.6 %) compared to bulk oil. Besides, compared with HIPPEs, HIPPEs gel showed poor printability because of improper printing adaptability and liquidity. In a nutshell, our work provides valuable information for developing novel HIPPEs gels for various food applications.

Investigating mechanical and inflammatory pathological mechanisms in osteoarthritis using MSC-derived osteocyte-like cells in 3D.

Changes to bone physiology play a central role in the development of osteoarthritis with the mechanosensing osteocyte releasing factors that drive disease progression. This study developed a humanised in vitro model to detect osteocyte responses to either interleukin-6, a driver of degeneration and bone remodelling in animal and human joint injury, or mechanical loading, to mimic osteoarthritis stimuli in joints. Human MSC cells (Y201) were differentiated in 3-dimensional type I collagen gels in osteogenic media and osteocyte phenotype assessed by RTqPCR and immunostaining. Gels were subjected to a single pathophysiological load or stimulated with interleukin-6 with unloaded or unstimulated cells as controls. RNA was extracted 1-hour post-load and assessed by RNAseq. Markers of pain, bone remodelling, and inflammation were quantified by RT-qPCR and ELISA. Y201 cells embedded within 3D collagen gels assumed dendritic morphology and expressed mature osteocytes markers. Mechanical loading of the osteocyte model regulated 7564 genes (Padj p<0.05, 3026 down, 4538 up). 93% of the osteocyte transcriptome signature was expressed in the model with 38% of these genes mechanically regulated. Mechanically loaded osteocytes regulated 26% of gene ontology pathways linked to OA pain, 40% reflecting bone remodelling and 27% representing inflammation. Load regulated genes associated with osteopetrosis, osteoporosis and osteoarthritis. 42% of effector genes in a genome-wide association study meta-analysis were mechanically regulated by osteocytes with 10 genes representing potential druggable targets. Interleukin-6 stimulation of osteocytes at concentrations reported in human synovial fluids from patients with OA or following knee injury, regulated similar readouts to mechanical loading including markers of pain, bone remodelling, and inflammation. We have developed a reproducible model of human osteocyte like cells that express >90% of the genes in the osteocyte transcriptome signature. Mechanical loading and inflammatory stimulation regulated genes and proteins implicated in osteoarthritis symptoms of pain as well as inflammation and degeneration underlying disease progression. Nearly half of the genes classified as 'effectors' in GWAS were mechanically regulated in this model. This model will be useful in identifying new mechanisms underlying bone and joint pathologies and testing drugs targeting those mechanisms.

Fabrication and evaluation of some characteristics of the skin's dermis gel direction to application in regenerative medicine

Objective:The tight connection between the cell-extracellular matrix (ECM - Extracellular matrix) is the foundation of tissue development and repair. The extracellular framework simulates the biological properties of organism-based ECM. The ECM of the skin’s dermis is a natural material, containing ingredients ideal for creating products that help tissue heal. This study focuses on the production of gel products from human skin ECM. The skin ECM is gelled by dissolving in a pepsin enzyme solution.Method: 3D gel formation process using neutral enzyme solution and incubation under physiological conditions. Gel samples were evaluated for speed and formability. Additionally, the dermal gel preparation was evaluated for its effects on the survival and proliferation of human fibroblasts in vitro by toxicity testing and proliferation testing, for 10 days. Results: Direct and extract toxicity assessments showed that the ECM gel regimen was safe for fibroblast survival. At the same time, fibroblasts had proliferation properties after 10 days in culture conditions with gel extract.Conclusion: These results showed that the ECM gel product regimen has the ability to positively impact the biological properties of cells and has the potential for application in the field of regenerative medicine.

Improving the properties of TiC steel bonded cemented carbides by optimizing the slurry rheology, printing path and shape design of 3D gel printing

TiC steel bonded cemented carbide was modeled by an extrusion-based 3D gel printing(3DGP) method. The rheological behavior of slurry was studied to control the slurry extrusion and modeling. The effects of printing parameters, printing path and modeling complexity were researched to get a printed sample without defects. The results indicated that the slurry with a solid loading of 50 vol% (85 wt%) was prepared, and its viscosity change is very little during 24 h in case of a higher shear rate like a nozzle. The viscosity of the slurry decreases with increasing the extrusion pressure and nozzle diameter. The skewed pattern of filaments eliminated pores in printed samples in comparison with the rectangular pattern under the condition of straight lines of the printing path. Pores at the corners of a model can be eliminated by changing the printing path from concentric lines to zigzag lines or two sets of slanted parallel lines. The modeling complexity without a support structure can be revealed by printing tilt cylinders with different angles, and the local parts on a model with a tilt angle of <45° can be printed accurately without designing a support structure. Improving the 3DGP procedure based on these experiences, the TiC steel bonded cemented carbide samples had properties similar to those prepared by conventional powder metallurgy methods.

Enhancement of Chondrogenic Markers by Exosomes Derived from Cultured Human Synovial Fluid-Derived Cells: A Comparative Analysis of 2D and 3D Conditions.

The goal of this pilot study was to investigate the effects of exosomes derived from synovial fluid-derived cells (SFDCs) cultured under normoxic conditions in a two-dimensional (2D) monolayer or encapsulated within a three-dimensional (3D) matrix for chondrogenic differentiation in vitro and cartilage defect repair in vivo. Synovial fluid samples were obtained from three patients, and SFDCs were isolated and expanded either in a 2D monolayer culture or seeded within a transglutaminase cross-linked gelatin (Col-Tgel) to create a 3D gel culture. Exosomes derived from each environment were isolated and characterized. Then, their effects on cartilage-cell proliferation and chondrogenic differentiation were assessed using an in vitro organoid model, and their potential for enhancing cartilage repair was evaluated using a rat cartilage defect model. SFDCs obtained from different donors reached a state of senescence after four passages in 2D culture. However, transferring these cells to a 3D culture environment mitigated the senescence and improved cell viability. The 3D-cultured exosomes exhibited enhanced potency in promoting chondrogenic differentiation, as evidenced by the increased expression of chondrogenic genes and greater deposition of cartilage-specific extracellular matrix. Furthermore, the 3D-cultured exosomes demonstrated superior effectiveness in enhancing cartilage repair and exhibited better healing properties compared to exosomes derived from a 2D culture. The optimized 3D culture provided a more favorable environment for the proliferation of human synovial cells and the secretion of exosomes compared to the 2D culture. The 3D-cultured exosomes exhibited greater potential for promoting chondrogenic gene expression in vitro and demonstrated improved healing properties in repairing cartilage defects compared to exosomes derived from the 2D culture.