Thick Gel Research Articles

Assessment of Pudding Formulations Using Lyophilized Apricot, Plum, and Plum–Apricot Powders: Texture, Bioactivity, and Sensory Quality

The food sector is constantly responding to consumers’ increased demands concerning healthy nutrition and beneficial ingredients. This study presented the development of three pudding alterations using lyophilized fruit (apricots, plum–apricots, and plums) powders. The same concentrations of fruit powder fully substituted the sugar in each formulation. The results showed that each new formulation formed a thick gel consistency and had full water-holding capacity at 24 h of storage. The color differed according to the established CIE-lab data. The lightness varied from 42.57 ± 1.97 (pudding formulation using plum powder) to 81.91 ± 1.18 (control sample). The total soluble solids and titratable acidity showed that the control sample was different from each new formulation. The water activity was similar in all studied samples varying from 0.978 ± 0.003 to 0.989 ± 0.001, and the plum and plum–apricot formulations had a pH near the control samples, at 6.54 and 7.23, respectively. The antioxidant activity, total polyphenol content, and total flavonoid content were also evaluated. The ABTS assay revealed the highest results compared to the other three applied methods. The sensory evaluation showed that it is necessary to further improve the recipes for better consumer perception.

Fundamental investigation on a new methodology to fabricate thin ion gel membranes for CO2 separation

A new method for fabricating thin ion gel membranes is proposed in this study. A precursor solution of a hydrophobic tough ion gel composed of an interpenetrating polymer network (IPN) and 80 wt% ionic liquid (IL) was spin coated onto a water-soluble sacrificial layer (poly(sodium 4-styrenesulfonate) (PSS-Na)) and a thin ion gel membrane was obtained after dissolving the sacrificial layer in IL-saturated water. Subsequently, the thin ion gel membrane was transferred onto a porous support membrane for obtaining a thin-film composite (TFC) membrane. The TFC membranes showed the same CO2 permeability as the thick ion gel membrane prepared using the same ion gel precursor solution, which indicates that the thin ion gel layer on the TFC membrane was defect free and contained the desired amount of IL. The TFC membrane with 9.3-μm-thick ion gel layer displayed the CO2 permeance of 98.2 GPU and CO2/N2 permselectivity of 31. This CO2 permeation performance was maintained for at least 200 h, indicating the good long-term stability of the prepared thin ion gel layer. The proposed method for forming a thin ion gel layer can be applied to other ion gels with different ILs.

Microvascular Engineering for the Development of a Nonembedded Liver Sinusoid with a Lumen: When Endothelial Cells Do Not Lose Their Edge.

Microvascular engineering seeks to exploit known cell-cell and cell-matrix interactions in the context of vasculogenesis to restore homeostasis or disease development of reliable capillary models in vitro. However, current systems generally focus on recapitulating microvessels embedded in thick gels of extracellular matrix, overlooking the significance of discontinuous capillaries, which play a vital role in tissue-blood exchanges particularly in organs like the liver. In this work, we introduce a novel method to stimulate the spontaneous organization of endothelial cells into nonembedded microvessels. By creating an anisotropic micropattern at the edge of a development-like matrix dome using Marangoni flow, we achieved a long, nonrandom orientation of endothelial cells, laying a premise for stable lumenized microvessels. Our findings revealed a distinctive morphogenetic process leading to mature lumenized capillaries, demonstrated with both murine and human immortalized liver sinusoidal endothelial cell lines (LSECs). The progression of cell migration, proliferation, and polarization was clearly guided by the pattern, initiating the formation of a multicellular cord that caused a deformation spanning extensive regions and generated a wave-like folding of the gel, hinged at a laminin-depleted zone, enveloping the cord with gel proteins. This event marked the onset of lumenogenesis, regulated by the gradual apico-basal polarization of the wrapped cells, leading to the maturation of vessel tight junctions, matrix remodeling, and ultimately the formation of a lumen─recapitulating the development of vessels in vivo. Furthermore, we demonstrate that the process strongly relies on the initial gel edge topography, while the geometry of the vessels can be tuned from a curved to a straight structure. We believe that our facile engineering method, guiding an autonomous self-organization of vessels without the need for supporting cells or complex prefabricated scaffolds, holds promise for future integration into microphysiological systems featuring discontinuous, fenestrated capillaries.

A 96-Well Polyacrylamide Gel for Electrophoresis and Western Blotting.

Western blotting is a stalwart technique for analyzing specific proteins and/or their post-translational modifications. However, it remains challenging to accommodate more than ~10 samples per experiment without substantial departure from trusted, established protocols involving accessible instrumentation. Here, we describe a 96-sample western blot that conforms to standard 96-well plate dimensional constraints and has little operational deviation from standard western blotting. The main differences are that (i) submerged polyacrylamide gel electrophoresis is operated horizontally (similar to agarose gels) as opposed to vertically, and (ii) a 6 mm thick gel is used, with 2 mm most relevant for membrane transfer (vs ~1 mm typical). Results demonstrate both wet and semi-dry transfer are compatible with this gel thickness. The major tradeoff is reduced molecular weight resolution, due primarily to less available migration distance per sample. We demonstrate proof-of-principle using gels loaded with molecular weight ladder, recombinant protein, and cell lysates. We expect the 96-well western blot will increase reproducibility, efficiency (cost and time ~8-fold), and capacity for biological characterization relative to established western blots.

Indenting a thick gel with a solid spherical inclusion

A spherical inclusion is embedded in a soft gel block. A vertical force is applied on the gel surface by means of a spherical indenter. The loading axis is not aligned with the inclusion but placed at a horizontal offset displacement from the inclusion. The measurement of indentation force and inclusion trajectory are compared to the computational results from two-dimensional (2D) Finite Element Analysis (FEA) simulations. A discernible instability emerges when the indentation reaches a critical depth, in accordance with the Southwell instability theory. The three-dimensional (3D) trajectory shows distinct features that were previously not captured by the 2D FEA simulations.

Use of ultrasound gel to mitigate risks of skin burns from non-actively cooled mic rowave applicators

The purpose of this study is to investigate the potential of using ultrasound gel to mitigate the risks of skin burn at the insertion site during microwave ablation (MWA) using non-actively cooled applicators. Ex vivo experiments in porcine tissue were conducted using two identical MWA systems. Five MWA scenarios were tested at different applicator insertion depths with an ultrasound gel layer applied at the applicator insertion sites: 8 cm insertion depth with and without 4 cm thick gel, 10 cm insertion depth with and without 2 cm thick gel, and 12 cm insertion depth without gel (reference). In all experiments, temperature elevations at the applicator insertion site on the tissue surface were recorded using thermal sensors in all experiments during 10-min MWA. The application of ultrasound gel and increasing applicator insertion depths resulted in measurable reductions in temperature elevations at the applicator insertion sites. For an insertion depth of 8 cm, the temperature elevations were 39.9 ± 4.7°C and 23.2±6.5°C without and with gel, respectively (P < 0.001). For an insertion depth of 10 cm, the temperature elevations were 20.8 ± 1.5°C and 14.4 ± 1.5°C without and with gel, respectively (P < 0.001). The maximal temperature elevations corresponding to an 8 cm insertion depth with gel were comparable with those corresponding to a 10 cm insertion depth without gel. Similarly, the maximal temperature elevations (12.2 ± 1.8°C) corresponding to 12 cm insertion depth without gel were comparable to those corresponding to 10 cm insertion depth with gel. Applying ultrasound gel at the applicator insertion site can significantly reduce temperature elevations at the tissue surface during MWA procedures.

GUAR GUM IN THERAPEUTICS: A SUCCINCT EXPLORATION

Guar gum, extracted from the seeds of Cyamopsis tetragonolobus, has gained prominence for its unique properties, forming a thick gel in water and releasing fatty acids through fermentation. Originating in Pakistan and India, it found industrial significance in the US during the 1940s. The galactomannan in guar's endosperm, a polysaccharide of d-mannose and d-galactose, imparts rapid solubility, pH stability, and biodegradability. Beyond its industrial applications, guar gum exhibits a myriad of health benefits. Delving into the botanical symphony of guar seeds reveals a poetic composition, and enzymatic exploration unravels the whimsical ballet of galactose side groups. Guar gum transcends its botanical origins to become a dietary sage, influencing serum cholesterol levels and aiding in weight management. Its journey through the digestive system orchestrates nuanced reductions in blood glucose and insulin, showcasing its potential for diabetes assistance.The manufacturing process involves splitting, hydration, and various treatments, resulting in guar gum's characteristics as a thickening agent with tasteless and odorless properties. Stability studies affirm its consistent performance over time, and its safety for target species, consumers, and the environment is established. Exploring guar gum's therapeutic applications reveals its potential in wound healing, inflammatory bowel disease treatment, and as a preventive measure against ulcers. Its role as a dietary fiber extends to managing irritable bowel syndrome symptoms, reducing blood sugar and cholesterol levels, promoting weight loss, and aiding in regular bowel movements. The article recommends a daily intake of 28g for adult women and 36g for men, achievable through the consumption of guar gum. Clinical studies demonstrate its positive impact on duodenal ulcers, providing relief, increasing satiety, and preventing symptoms. With its multifaceted applications, guar gum emerges as a fascinating substance intertwining chemistry, medicine, and industry.

Towards improved antifouling: Exploring xanthan gum hydrogel coatings

This study explored xanthan gum hydrogel coatings as an approach to more environmental friendly fouling control strategies. Xanthan gum served as a filler in a conventional rosin/acrylic coating matrix, leading to the formation of a 150 μm thick gel layer on the coating surface upon seawater exposure. While biocide-free xanthan hydrogel coatings did not have significant antifouling capabilities, a synergistic effect between hydrogel and cuprous oxide was observed. During field tests at the CoaST Maritime Test Center (CMTC), it was found that the cuprous oxide concentration could be reduced by at least 50 wt% for the hydrogel coating without compromising the antifouling performance. Two possible causes were identified. First, the hydrogel coating could maintain a higher release rate over a prolonged period and second, the hydrogel was able to accumulate Cu2+, increasing retention time on the surface, creating a hostile environment. A synergistic enhancement in gel strength, yield point, and flow point was observed when xanthan was combined with konjac mannan. While promising for static applications, the rheological assessments of the different gels highlighted challenges for the application in dynamic settings like moving ships.

Immunoblot Analysis from Single Cells Using Milo™ Single-Cell Western Platform.

In this new era of precision medicine, characterization of single-cell subpopulations to better understand disease etiology is paramount. It is thus an opportune time to explore techniques that allow molecular analysis of single cells and to better understand the basis of pathogenesis of diseases like cancer. Single-cell western blotting is one such method that allows analysis of single cells at the protein level. In contrast to traditional western blotting, which relies heavily on bulk analysis of lysates generated from tissues and is often indicative of the population average, this technique allows analysis of lysates from single-cell subpopulations thereby providing a glimpse into cell heterogeneity. The method entails the use of a chip containing 30μm thick photoactivated polyacrylamide gel spotted with nearly 6400 microwells. Single cells loaded on the chip are captured in the microwells by passive gravity and are then lysed and electrophoresed using the MILO™ single-cell western platform. This method forgoes the use of transfer of proteins on a PVDF and a nitrocellulose membrane, as performed in traditional western blotting, and all other steps including probing of primary and fluorescent secondary antibodies against the protein of interest are performed directly on the chip. The proteins of interest can then be visualized by scanning a chip with the use of a microarray scanner. The entire procedure can be performed in as less as 4-6h, and thus this method provides several advantages over traditional western blotting.

Ultrasoft silicone gels with tunable refractive index for traction force microscopy.

We formulate and characterize silicone gels near the gelation threshold with tunable refractive index, 1.4 < n < 1.49, and small viscoelastic moduli, G'∼1 Pa, for use in traction force microscopy. The near-critical gels have low-frequency storage plateau moduli between 50 Pa and 1 Pa, with loss moduli that are more than fifty times lower at low frequencies. The gels are linearly elastic up to strains of at least 50%. The refractive index of the gel is tuned to eliminate spherical aberrations during confocal imaging thereby minimizing signal loss when imaging through thick gel substrates. We also develop an index-matched colloidal particle, stabilized by a silicone brush, that can be dispersed throughout the gel. These particles can be used to determine the deformation of the gel. The combination of mechanical and optical properties of these near-critical gels extends the lower limit of stresses that can be measured with traction force microscopy to single mPa values, while minimizing optical aberrations.

Electrode laminated with ion-selective blocking layer for use in vanadium redox flow batteries

2 μm thick meta-polybenzimidazole (PBI) films effectively block permeation of vanadium ions in vanadium redox flow batteries, but are usually reinforced with supports to guarantee mechanical stability. Here, we eliminate the use of an additional support by laminating a 2 μm thick 10-wt% dibromoxylene crosslinked PBI layer directly on carbon paper. The total area specific resistance (ASR) of the two PBI films is 156.8 mΩ cm2 in 1.5 M V4+/3 M sulfuric acid solution, 26 % lower than that of Nafion 211. VRFB cells are made by assembling a membrane between two PBI-laminated carbon paper electrodes. These electrodes simplify membrane selection, because high selectivity is not anymore required, and chemical stability of the membranes against VO2+ is less crucial. An example cell is made with a 70 μm thick Gel PBI membrane. Membrane and PBI layers exhibit an ASR of 177.8 mΩ cm2 in 1.5 M V4+/3 M sulfuric acid solution, 18 % lower than that of Nafion 211. The selectivity of proton over vanadium ion is 4.2 × 1014 S s m−3, 9 times better than that of Nafion 211. In a VRFB, a stable energy efficiency of 87.6 % at 75 mA cm−2 compared to 82.3 % for Nafion 211 is obtained.

Durability, Microstructure, and Optimization of High-Strength Geopolymer Concrete Incorporating Construction and Demolition Waste

The incorporation of construction and demolition (C&amp;D) waste in concrete production has gained great importance toward sustainability, especially in geopolymer concrete. In this study, ground granulated blast-furnace slag (GGBFS) and fine aggregate of normal geopolymer concrete were partially replaced by clay brick powder (CBP) and fine clay brick (FCB) derived from C&amp;D waste, respectively, aiming to produce high-strength geopolymer concrete (HSGC). Fly ash (FA) was also used as a partial replacement for GGBFS in normal geopolymer concrete. Twenty HSGC mixtures were designed using the response surface methodology with three variables, including CBP (0–25%), FA (0–25%), and FCB (0–50%). The performance of the proposed HSGC mixtures was assessed by measuring several mechanical and durability properties. In addition, a variety of physicochemical methods, including X-ray fluorescence spectroscopy, X-ray diffraction, and scanning electron microscopy, were used to examine the mineralogical and microstructural characteristics of the control and the developed mixtures. The findings revealed that the compressive, splitting tensile, and flexural strengths of the HSGC made with C&amp;D waste ranged from 38.0 to 70.3 MPa, 4.1 to 8.2 MPa, and 5.2 to 10.0 MPa, respectively. The results also indicated that the incorporation of FA is an essential parameter to eliminate the negative impacts of C&amp;D waste addition on concrete workability. The optimal proportions for the HSGC were 5% for CBP, 5% for FA, and 40% for FCB, which were determined to generate the optimized HSGC with the highest mechanical performance, according to the verified models and optimization findings. The physicochemical analyses showed that the thick amorphous geopolymeric gel predominated the nonporous structure of the optimized HSGC, which had good mechanical characteristics. Furthermore, the anti-carbonation performance and freezing resistance of the optimal HSGC increased by 17.7% and 14.6%, respectively, while the apparent porosity decreased by 8.4%.

The Effect of Variations in HPMC and Carbopol Bases on The Physical Stability of Okra (Abelmoschus esculentus L.) Fruit Gel Formulations

Okra fruit (Abelmoschus esculentus L.) is a vegetable that is often used as medicine. Okra fruit contains flavonoids which are antioxidants. Gel formulation with a concentration of 5%, and various combinations of HPMC and carbopol bases. This research aims to determine the physical stability of gel preparations and the effect of variations in the concentration of gelling ingredients in the preparations. The gel formulation consists of 4 formulas, namely F0, F1, F2, and F3. Physical stability tests include organoleptic tests (odor, color and texture), homogeneity, pH, spreadability, stickiness, viscosity and synergy. Tests were carried out for 14 days of storage, namely on days 1, 3, 5, 7, and 14 at room temperature (25℃). The observation results showed that in the organoleptic test there was no change in color, odor and texture in the gel preparation during 14 days of storage. The four gel formulas are homogeneous and there is no synergy. Variations in the combination of HPMC and carbopol bases affect the physical properties of the gel, including pH, viscosity, spreadability and adhesion. HPMC and Carbopol affect the pH of the preparation, the higher the Carbopol content and the lower the HPMC content, the more acidic it is. Carbopol and HPMC affect the values of spreadability, viscosity and adhesion because the higher the concentration of carbopol and HPMC produces a thick gel preparation so that the spreadability decreases, viscosity increases and adhesion also increases.

Clinical Application of Individualized 3D-Printed Chest Wall Conformal Device in IMRT for Post-Mastectomy Breast Cancer.

Background Breast cancer is the most common malignant tumour in women. Radical mastectomy with postoperative radiotherapy is now the standard treatment for locally advanced breast cancer. Intensity-modulated radiotherapy (IMRT) has now been developed, which employs linear accelerators to deliver precise radiation to a tumour while minimizing the dose to surrounding normal tissue. It significantly improves the efficacy of breast cancer treatment. However, there are still some flaws that must be addressed. Objective To assess the clinical application of the three-dimensional (3D)-printed chest wall conformal device for breast cancer patients who need to be treated by chest wall intensity modulated radiotherapy (IMRT) after radical mastectomy. Methods The 24 patients were divided into three groups. During a computed tomography (CT) scan, patients in the study group were fixed by a 3D-printed chest wall conformal device, nothing in control group A, and a traditional 1-cm thick silica gel compensatory pad on the chest wall in control group B. The parameters of mean Dmax, Dmean, D2%, D50%, D98%, the conformity index (CI), and the homogeneity index (HI) of the planning target volume (PTV) are compared. Results The study group had the best dose uniformity (HI = 0.092) and the highest conformation (CI = 0.97), the worst in control group A (HI = 0.304, CI = 0.84). The mean Dmax, Dmean, and D2% of the study group were lower than control groups A and B (p<0.05). The mean D50% was higher than control group B (p<0.05), while the mean D98% was higher than control groups A and B (p<0.05). The mean Dmax, Dmean, D2%, and HI of control group A were higher than control group B (p<0.05), whereas the mean D98% and CI were lower than control group B (p<0.05). Conclusion By improving the efficacy of postoperative radiotherapy for breast cancer, using 3D-printed chest wall conformal devices may greatly improve the accuracy of repeating position fixation, increase the dose on the skin surface of the chest wall, optimise the dose distribution of the target area, and thus further reduce tumour recurrence and prolong patients' survival.

The Physical, Sensory, and Microbial Qualities of Broth Gels Enclosing Food Cubes and Their Changes during Cold Storage

Due to their unusual textural properties and semblance, gel foods have been welcomed by consumers. In this study, we designed a novel gel food, that is, broth jellies that enclosed particular food dices (shrimp, chicken, and potatoes). Briefly, various ratios of gelling molecules (gelatin and κ-carrageenan) were added to chicken broth, the food dices were placed in the center of the gels, and their characteristics and stabilities were verified during cold storage (4 °C) for 14 days. As a result, the mix of κ-carrageenan and gelatin led to the formation of firm cross-junctions with an elevated hardness compared to gelatin singular gel. In contrast, the gelatin sole gel showed different sensory attributes, such as a high chewiness and meltiness. The thick gel barriers of the products fairly increased the stability of the inner food ingredients. By blocking the loss of moisture, the texture and sensory traits were well preserved; moreover, the gelling molecules greatly impeded microbial decay by decreasing the water activity due to their strong water-binding capacity. In conclusion, the mix ratio of gelatin and κ-carrageenan affected the gel characteristics by shifting the gel matrices, and the gel barriers improved the food quality and inner food preservability.

Antioxidant serum gel formulation with a combination of secretome from mesenchymal stem cells and rosemary oil

Rosemary Oil (Rosmarinus officinalis) contains carnosic acid, carnosol, and rosmarinic acid, which are sources of active antioxidants. The Secretome of MSC has growth factors such as antioxidants that protect HDFs. This study aimed to obtain a gel formulation from secretome combinates with Rosemary Oil and test its effect as an antioxidant. The gel formulation contains Rosemary Oil as an antioxidant, propylene glycol as humectants, Carbomer 940 as a gelling agent, triethanolamine as an alkalizing agent, DMDM Hydantoin as preservative, and aquadest. The evaluation tests of gel preparations include organoleptic tests, homogeneity, viscosity, pH, dispersion, syneresis, and stability. Antioxidant activity test using DPPH method (1.1-Diphenyl-2 Picrylhydrazil). The results show the gel was in the form of a thick gel, cloudy white and yellowish, having a characteristic smell like rosemary plants. It also has ease of use, is homogeneous, has a cooling sensation, and has good solubility during washing. The gel has an average pH value of 6.39; viscosity <30,000 cp; the average dispersion value is 5.71 cm. Rosemary Oil gel preparations provide antioxidant activity, indicated by the IC50 value. Gel preparations with 5% secretome with 2.5% rosemary oil had an antioxidant activity with an IC50 value of 11.4501 μg/ml. Based on these results, it can be concluded that the Secretome with rosemary oil gel formulations were proven to have an antioxidant effect and showed an increase in antioxidant activity in the formula added with Secretome (P <0.05)

Optimizing phenol-modified hyaluronic acid for designing shape-maintaining biofabricated hydrogel scaffolds in soft tissue engineering

In this study, we developed a well-printable biomaterial ink for 3D printing of shape-maintaining hydrogel scaffolds. The hydrogel base comprised tyramine-modified hyaluronic acid (HA-Tyr) and gelatin methacrylate (GelMA) and was dually cross-linked. Using the Box-Behnken design, we explored how varying the ink composition affected fiber formation and shape preservation. By adjusting the polymer ratios, we produced a stable hydrogel with varying responses, from a viscous liquid to a thick gel, and optimized 3D scaffolds that were structurally stable both during and after printing, offering precision and flexibility. Our ink exhibited shear-thinning behavior and high swelling capacity, as well as ECM-like characteristics and biocompatibility, making it an ideal candidate for soft tissues matrices with storage modulus of around 300 Pa. Animal trials and CAM assays confirmed its biocompatibility and integration with host tissue.

Influence of 3-aminopropyltriethoxysilane/tetraethylorthosilicate mixture pretreatment on the microstructure and corrosion resistance of zeolite coating

ABSTRACT The influence of silane pretreatment with five different volume ratios (100/0, 75/25, 50/50, 25/75, and 0/100) of 3-aminopropyltriethoxysilane (APTES)/tetraethylorthosilicate (TEOS) on microstructure and corrosion resistance of the hydrothermal synthesized zeolite coatings on the H13 steel substrates was investigated. The surface of the zeolite coatings on the 100/0, 75/25, and 50/50 mixture of the APTES/TEOS pretreated substrates was composed of intergrown rectangular particles. Additionally, pores were observed. A 25/75 mixture of APTES/TEOS pretreatment smoothed the edges and angles of zeolite particles with gel-like materials filled in the pores. In pure TEOS pretreatment, microcracks, and much gel-like materials were observed on the zeolite coating. The electrochemical test revealed that the zeolite coating on a 50/50 mixture of the APTES/TEOS pretreated substrate exhibited the highest corrosion resistance in 3.5 wt-% NaCl solution. This was because a 50/50 mixture of APTES/TEOS pretreatment advantageously promoted development of a dense and thick gel layer, which enhanced the intergrowth of zeolite particles.

Clinical Study and Toxicity Tests of Disclosing Agent Aloe Vera Gel

Disclosing agents function to visualize and identify dental plaque on the tooth surface, making it very useful for viewing transparent bacterial plaque for the purposes of oral hygiene instruction, evaluation and research. Aloe vera (Aloe vera) has a unique texture because it is in the form of a gel which has anti-inflammatory, wound healing, antibacterial and anticancer properties. Aloe vera can be developed as a disclosing agent. Clinical trials and toxicity tests can be the basis for the clinical use of aloe vera gel. The purpose of this study was to determine the ability of aloe vera gel as a disclosing agent based on clinical trials and toxicity tests. The research method is by carrying out sample preparation, extraction, gel preparation, clinical trials on human test subjects, and toxicity tests with the BSLT method. Data were analyzed descriptively, linear regression. The test results showed that the average plaque score in formula I (thick gel) was 3.62, while the average plaque score in formula II (less viscous gel) was 2.58. This shows that the more viscous aloe vera gel formula is better than the less viscous aloe vera gel. Based on the test, it is known that the average LC50 value is 2596.88 µg/ml. According to the literature, if the LC50 value is above 1000 µg/ml then the sample does not have a toxic effect.&#x0D; &#x0D;

Tissue-Like 3D Standard and Protocols for Microscope Quality Management.

This article outlines a global study conducted by the Association of Biomedical Resource Facilities (ABRF) Light Microscopy Research Group (LMRG). The results present a novel 3D tissue-like biologically relevant standard sample that is affordable and straightforward to prepare. Detailed sample preparation, instrument-specific image acquisition protocols and image analysis methods are presented and made available to the community. The standard consists of sub-resolution and large well characterized relative intensity fluorescence microspheres embedded in a 120 µm thick 3D gel with a refractive index of 1.365. The standard allows the evaluation of several properties as a function of depth. These include the following: 1) microscope resolution with automated analysis of the point-spread function (PSF), 2) automated signal-to-noise ratio analysis, 3) calibration and correction of fluorescence intensity loss, and 4) quantitative relative intensity. Results demonstrate expected refractive index mismatch dependent losses in intensity and resolution with depth, but the relative intensities of different objects at similar depths are maintained. This is a robust standard showing reproducible results across laboratories, microscope manufacturers and objective lens types (e.g., magnification, immersion medium). Thus, these tools will be valuable for the global community to benchmark fluorescence microscopes and will contribute to improved scientific rigor and reproducibility.