Isothermal microcalorimetry provides new insights into biofilm variability and dynamics.

The purpose of this study was to investigate a three-species in vitro biofilm with peri-implantitis-related bacteria for its variability and metabolic activity. Streptococcus sanguinis, Fusobacterium nucleatum, and Porphyromonas gingivalis were suspended in simulated body fluid containing 0.2% glucose to form biofilms on polished, protein-coated implant-grade titanium disks over 72 h using a flow chamber system.

Rapid detection of urinary tract pathogens using microcalorimetry: principle, technique and first results.

Unlabelled: What's known on the subject? and What does the study add? Microcalorimetry has been applied in several microbiological studies, but never in a clinical urological context. In addition, basic knowledge on the growth of urinary pathogens in urine is still scarce and data regarding the growth rate of many urinary pathogens in urine are still not available. The study demonstrates that this innovative application of microcalorimetry is useful in (i) investigating the growth of urinary pathogens in sterilized urine and (ii) as a rapid tool for diagnosis of urinary infection as well as for further identification of the causative infectious agent.

Acrylamide Polymer Double-Network Hydrogels: Candidate Cartilage Repair Materials with Cartilage-Like Dynamic Stiffness and Attractive Surgery-Related Attachment Mechanics.

Background: In focal repair of joint cartilage and meniscus, initial stiffness and strength of repairs are generally much less than surrounding tissue. This increases early failure potential. Secure primary fixation of the repair material is also a problem.

Use of an isothermal microcalorimetry assay to characterize microbial oxalotrophic activity.

Isothermal microcalorimetry (IMC) has been used in the past to monitor metabolic activities in living systems. A few studies have used it on ecological research. In this study, IMC was used to monitor oxalotrophic activity, a widespread bacterial metabolism found in the environment, and particularly in soils.

Closed ampoule isothermal microcalorimetry for continuous real-time detection and evaluation of cultured mammalian cell activity and responses.

Closed ampoule isothermal microcalorimetry (IMC) is a simple, powerful, nondestructive, and convenient technique that allows continuous, real-time detection and evaluation of cultured cell activity and responses. At a selected set temperature, IMC measures the heat flow between a sample and a heat sink and compares it to the heat-flow between a thermally inactive reference and the heat sink. Since heat flow rates are proportional to the rates of chemical reactions and changes of state, IMC provides a means for dynamically following these processes in any type of specimen - including ones containing cultured cells.

Engineering human cell-based, functionally integrated osteochondral grafts by biological bonding of engineered cartilage tissues to bony scaffolds.

In this study, we aimed at developing and validating a technique for the engineering of osteochondral grafts based on the biological bonding of a chondral layer with a bony scaffold by cell-laid extracellular matrix. Osteochondral composites were generated by combining collagen-based matrices (Chondro-Gide) containing human chondrocytes with devitalized spongiosa cylinders (Tutobone) using a fibrin gel (Tisseel). We demonstrate that separate pre-culture of the chondral layer for 3 days prior to the generation of the composite allows for (i) more efficient cartilaginous matrix accumulation than no pre-culture, as assessed histologically and biochemically, and (ii) superior biological bonding to the bony scaffold than 14 days of pre-culture, as assessed using a peel-off mechanical test, developed to measure integration of bilayered materials.

Use of isothermal microcalorimetry to monitor microbial activities.

Isothermal calorimetry measures the heat flow of biological processes, which is proportional to the rate at which a given chemical or physical process takes place. Modern isothermal microcalorimeters make measurements of less than a microwatt of heat flow possible. As a result, as few as 10 000-100 000 active bacterial cells in culture are sufficient to produce a real-time signal dynamically related to the number of cells present and their activity.

Microcalorimetry: a novel method for detection of microbial contamination in platelet products.

Background: Measuring heat from replicating microorganisms in culture may be a rapid, accurate, and simple screening method for platelets (PLTs). Microcalorimetry for detection of microorganisms in in vitro contaminated PLT products was evaluated.

Study Design And Methods: Staphylococcus epidermidis, Staphylococcus aureus, Streptococcus sanguinis, Escherichia coli, Propionibacterium acnes, and Candida albicans were inoculated in single-donor apheresis PLTs to achieve target concentrations of 10(5), 10(3), 10, or 1 colony-forming units (CFU) per mL of PLTs.

Use of hydrodynamic forces to engineer cartilaginous tissues resembling the non-uniform structure and function of meniscus.

The aim of this study was to demonstrate that differences in the local composition of bi-zonal fibrocartilaginous tissues result in different local biomechanical properties in compression and tension. Bovine articular chondrocytes were loaded into hyaluronan-based meshes (HYAFF-11) and cultured for 4 weeks in mixed flask, a rotary Cell Culture System (RCCS), or statically. Resulting tissues were assessed histologically, immunohistochemically, by scanning electron microscopy and mechanically in different regions.

Effects of scaffold composition and architecture on human nasal chondrocyte redifferentiation and cartilaginous matrix deposition.

We investigated whether the post-expansion redifferentiation and cartilage tissue formation capacity of adult human nasal chondrocytes can be regulated by controlled modifications of scaffold composition and architecture. As a model system, we used poly(ethylene glycol)-terephthalate-poly(butylene)-terephthalate block copolymer scaffolds from two compositions (low or high PEG content, resulting in different wettability) and two architectures (generated by compression molding or three-dimensional (3D) fiber deposition) with similar porosity and mechanical properties, but different interconnecting pore architectures. Scaffolds were seeded with expanded human chondrocytes and the resulting constructs assessed immunohistochemically, biochemically and at the mRNA expression level following up to 4 weeks of static culture.