XTT assay for cytotoxicity assessment

We offer comprehensive test packages for verifying the quality of type II and type IIR face masks according to the EN 14683 standard. The tests included in the packages are required to label face masks with the CE marking. Medical face masks are divided into Types I and II according to their bacterial filtration efficiency. Type I masks are not intended for healthcare professionals, but for the public to prevent the spread of infectious diseases. Type II masks are further classified based on whether they are splash-resistant (Type IIR) or not (Type II). To comply with the European Standard EN 14683, Type II face masks must undergo the following quality tests: Bacterial filtration efficiency (BFE) - The ability of the face mask to filter the bacterium Staphylococcus aureus. The BFE is expressed as the percentage of colony-forming units (cfu) that have passed via aerosol through the facemask. If a face mask consists of two or more areas with different characteristics, these areas will be tested separately., Breathability (Differential pressure) - The amount of differential pressure required to draw air through a measured surface area at a constant flow rate., Microbial cleanliness (Bioburden) - The measurement of colony forming units per gram as per EN ISO 11737-1., Biocompatibility - The medical face mask manufacturer shall complete a biocompatibility evaluation according to ISO 10993-1 as a surface device with limited contact. The applicable toxicology testing regimen shall also be determined.. In addition to the above, Type IIR masks require the following test: Splash resistance - Performed according to ISO 22609, this test determines the ability of a face mask to resist penetration of splashes of liquid at different pressures.. The lower displayed price applies to the Type II mask test package, while the higher price also includes the splash resistance test required for Type IIR masks.

The MTT assay is a quantitative study to determine the potential biological reactivity of a mammalian cell culture in response to a medical device extract. It is one of the in vitro methods outlined in standard ISO 10993-5 for evaluating the cytotoxicity of medical devices. For the assay, the test item is extracted in cell culture medium, and the cells are grown in tissue culture plates and exposed to the test item extract. The plates are incubated, after which cell viability is assessed by measuring the conversion of the yellow MTT by the mitochondrial reductase enzymes into blue-violet insoluble formazan.  As only viable cells convert MTT into formazan, the number of viable cells correlates with the color intensity of the resulting cell culture, which is determined by photometric measurements. The medical device is considered non-cytotoxic if 70% or more of the cells are viable when compared to a control sample.

The NRU assay is a quantitative test to determine the potential biological reactivity of a mammalian cell culture in response to a medical device extract. It is described in Annex A of ISO 10993-5 and is one of the most commonly used methods for medical device cytotoxicity testing. The test item is extracted in cell culture medium, which is suitable for both polar and non-polar extracts. The cells are exposed to the extract, and their viability is assessed after staining with neutral red (NR) solution. The number of viable cells correlates with the color intensity determined by photometric measurements, as non-viable cells do not absorb NR. The medical device is considered non-cytotoxic if the percentage of viable cells is ≥ 70 % of the untreated control.

Cytotoxicity assessment is a crucial part of biocompatibility testing, which is performed to ensure that medical devices do not cause adverse reactions when in contact with the body. The assessment is required for practically all new medical devices to be approved in the EU (under the MDR) and the US (510(k) submission to the FDA). During cytotoxicity testing, the material's potential to damage or kill cells is assessed using in vitro methods. This involves exposing cultured cells to the material and observing any negative effects on cell health and viability. According to ISO 10993-5, cytotoxicity testing can be performed on an extract of the test material or the material itself, depending on the device type. The standard also lists several direct and indirect test methods. We can provide cytotoxicity tests using the methods listed below. Direct methods: Neutral red uptake (NRU) assay, MTT assay, XTT assay. Indirect methods: Filter diffusion, Agar diffusion. The displayed example price covers testing with the commonly used NRU method, performed under GLP. Please ask for a quote for your medical device.

MEM elution is a qualitative study to determine the cytotoxic properties of medical devices. It is often performed together with a quantitative test, such as the MTT or XTT assay. In the test, mammalian fibroblast cells are grown in a serum-supplemented minimum essential medium (MEM). Once the cells have been cultured, medical device extracts are introduced. After incubation, the overall health of the cells is visually observed under a light microscope and assigned a grade between 0 and 4, based on the extent of cellular damage. Grade 3 (moderate reactivity) or greater is considered a cytotoxic effect.

The purpose of cleaning validation studies is to show that reusable medical devices can be reprocessed effectively between uses so that patients are not exposed to pathogens. Depending on the device’s intended use and classification, appropriate reprocessing steps may include cleaning, disinfection, and/or sterilization. For cleaning validation more specifically, the testing procedure consists of three steps: Simulated contamination with artificial soils that accurately reflect clinically relevant soils, such as blood and other bodily fluids. , Cleaning (manual and/or automated), carefully following the manufacturer's instructions for parameters such as detergents, cleaning tools, water quality, and temperature. , Inspection, both visually and using quantitative methods relevant to the test soil (e.g., proteins, total organic carbon, or hemoglobin), to assess whether residual contaminants remain on the device.. Successful cleaning validation is often sufficient for non-critical reusable devices, such as blood pressure cuffs, monitors, and clutches. Semi-critical and critical devices will require further disinfection and/or sterilization validation studies, which we can also offer. The displayed example price covers a manual cleaning validation study with 6 reprocessing cycles and cleanability evaluations with visual inspection & protein content measurement. Test protocol formulation and reporting are also included.

We have various testing services available for ultrapure water. Pricing depends on the selected parameters and the number of samples. Please contact Measurlabs to get an offer. Note that we will provide suitable shipping containers based on the analyses that are ordered. Trace elements by ICP-MS For the determination of elemental impurities, we offer a basic 36-element and an extended 67-element package. The basic package includes the following 36 elements: Li, Be, B, Na, Mg, Al, K, Ca, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Ga, Ge, As, Sr, Zr, Nb, Mo, Ag, Cd, Sn, Sb, Ba, Ta, W, Pt, Au, Tl, Pb, and Bi. The extended analysis includes the following elements in addition to the basic package: Ce, Cs, Dy, Er, Eu, Gd, Hf, Ho, In, Ir, La, Lu, Hg, Nd, Os, Pd, Pr, Re, Rh, Rb, Ru, Sm, Sc, Se, Te, Tb, Th, Tm, U, Yb, and Y. Reporting limits depend on the element and specific sample matrix, but typically vary between 0.001 ppb and 0.6 ppb. For this analysis, samples must be delivered in Teflon containers. Hardness Hardness value can be calculated based on the ICP-MS results. Silicon and silica (Si, SiO2) Our service catalog includes the determination of total, dissolved, and colloidal silica (SiO2). Total silicon is analyzed using the ICP-OES technique, and dissolved silicon by UV-VIS (molybdenum heteropoly blue method). Colloidal silica is calculated as the difference between total silica and dissolved silica. Total organic and inorganic carbon (TOC and TIC) We offer TOC determination for ultrapure water samples with a 5 ppb quantification limit. For this analysis, samples must be delivered in certified 40 ml TOC vials. Total inorganic carbon (TIC) analysis can also be performed using a TOC analyzer. Anions by ion chromatography (IC) For anions, we have a basic package and a separate package for organic anions. The basic package includes the following anions: bromide(Br⁻), chloride (Cl⁻), fluoride (F⁻), nitrate (NO₃⁻), nitrite (NO₂⁻), phosphate (PO₄³⁻), and sulfate (SO₄²⁻). Analysis of organic anions includes: acetate, formate, glycolate, propionate, and butyrate. Reporting limits depend on the anion and sample matrix, but typically vary between 0.02 and 1 ppb for basic anions and are around 25 ppb for organic anions. For this analysis, samples must be delivered in HDPE bottles. Cations by ion chromatography (IC) The analysis package for cations includes the determination of the following cations: ammonium (NH4+), calcium (Ca2+), lithium (Li+), magnesium (Mg2+), potassium (K+), and sodium (Na+). Reporting limits typically vary between 2 ppb and 5 ppb. Samples must be delivered in HDPE bottles. PFAS compounds (24 compounds) Analysis includes PFOS, PFOA, PFNA, PFHxS, and 20 other selected PFAS compounds. The complete list of compounds can be provided upon request. The reporting limit is typically 1 ng/L. The sample must be delivered in a plastic PFAS-free bottle, preferably made from HDPE.

ISO 10993-23 is an internationally recognized standard for assessing the irritation potential of medical devices when they come into contact with skin, mucosal membranes, or subcutaneous tissues. Irritation tests performed according to the standard are commonly used to demonstrate compliance with EU MDR and FDA requirements. The appropriate testing approach is chosen based on the body contact site: Skin irritation tests evaluate whether a medical device or material causes localized skin irritation when it comes into direct contact with the skin. Testing can be conducted using in vivo or in vitro methods, depending on the device and the market area. , Intracutaneous reactivity tests apply to medical devices or materials that penetrate the skin or come into contact with deeper tissues. The goal is to determine whether extracts from such devices cause localized inflammatory responses in the dermis or subcutaneous layers.. The device itself is tested with a direct contact method, when possible. Alternatively, polar and non-polar solvents are used to prepare extracts that simulate potential leachables from the device. The displayed example price includes an in vivo direct skin irritation test performed under GLP. For a more accurate quote, do not hesitate to contact us with a description of your device and any additional requirements you may have for testing (e.g., market area, quality systems, in vivo vs. in vitro methods).

Standard ISO 22196 outlines a method for evaluating the antibacterial activity of plastics and other non-porous surfaces. The procedure involves inoculating the sample with a specified concentration of bacteria, typically Staphylococcus aureus or Escherichia coli, and incubating it under controlled conditions. After incubation, the number of viable bacteria on the test surface is compared to that on an untreated control surface. The difference is quantified as a logarithmic reduction, indicating the level of antibacterial activity. This method is widely recognized as reproducible and consistent, making it a reliable tool for assessing the efficacy of antibacterial treatments in industries such as healthcare, packaging, and consumer products. The lower end of the price range applies to testing with one bacterial strain, while the higher end includes analyses with both S. aureus and E. coli.

The ISO 11737-3 standard provides internationally recognized guidelines for bacterial endotoxin testing of medical devices. Tests described in the standard can be used to evaluate the pyrogenic potential of medical devices for batch release and to validate manufacturing, cleaning, and sterilization processes in terms of their capacity to prevent endotoxin contamination. The Limulus Amebocyte Lysate (LAL) test is the most common approach to endotoxin testing. ISO 11737-3 describes several LAL methods, including kinetic turbidimetric and chromogenic techniques. One routine LAL assay for one sample with a chromogenic method is included in the displayed example price. We can also offer custom bacterial endotoxin test packages, especially for large sample volumes. Please describe your testing needs using the form below to get a quote for your samples.