CHARACTERIZATION OF BIOCOMPATIBLE POLYMERS AS SCAFFOLD MATERIAL TO MIMIC THE SMALL INTESTINAL IN VITRO MICROENVIRONMENT

The small intestinal environment is one of the most important sites in the body where interactions between host and microbes take place. However, to this day this remains understudied, and this is where innovative in vitro models for the small intestinal ecosystem come in. We aim to recreate the small intestinal microenvironment with relevant physiological parameters inside of a bioreactor using state-of-the art techniques and assess how this model compares to the in vivo situation. As a first step, we screened for potential biocompatible materials that can be used as a scaffold for small intestinal epithelial cells, which should allow cell attachment, migration and mechanical support, as well as enable diffusion of vital cell nutrients and expressed products. We characterized two materials, methacrylamide-modified gelatin (gel-MOD) and electrospun silk fibroin (SF). Two types of small intestinal epithelial cells (Caco-2 and LS174T) were seeded together in a 90:10 ratio on gel-MOD patches. The cell viability was then monitored with over a period of 14 days using resazurin as a marker. Afterwards, cell morphology was examined using confocal microscopy. In addition, the diffusion of different-sized molecules (lucifer yellow, dextran 4kDa, dextran 10kDa)through gel-MOD and SF membranes was tested in a diffusion cell set-up. From this, the apparent permeability coefficient (Papp) was calculated. Results indicated that (I) the intestinal grew confluently on the gel-MOD patches and remained attached to the patches over a period of 14 days; (2) both gel-MOD and SF show adequate diffusion of the compounds and give physiologically relevant Papp values. Two materials (Methacrylamide-modified gelatin (gel-MOD) and Electrospun silk fibroin (SF)) were identified as suitable scaffold materials. In the future, this will be applied in a 3D-context. We will introduce the 3 essential key-players (epithelial cells, immune cells and microbial community) into an in vitro model using either gel-MOD or SF as a scaffold material for the epithelial cells and study the interaction by looking at cell differentiation, permeability and gene expression

The small intestine: dining table of host-microbiota meetings

International audienceAbstract Growing evidence suggests the importance of the small intestinal bacteria in the diet-host-microbiota dialogue in various facets of health and disease. Yet, this body site is still poorly explored and its ecology and mechanisms of interaction with the host are just starting to be unraveled. In this review, we describe the current knowledge on the small intestinal ecology, its composition and diversity, and how the intestinal bacteria in homeostatic conditions participate in nutrient digestion and absorption. We illustrate the importance of a controlled bacterial density and of the preservation of absorptive surface for the host's nutritional status. In particular, we discuss these aspects of the small intestinal environment in the framework of two disease conditions, namely small intestinal bacterial overgrowth (SIBO) and short bowel syndrome (SBS). We also detail in vivo, ex vivo and in vitro models developed to simulate the small intestinal environment, some applied for (diet-)host-bacteria interaction studies. Lastly, we highlight recent technological, medical and scientific advances applicable to investigate this complex and yet understudied body environment to broaden our knowledge in support of further progress in the medical practice, and to proceed towards the integration of the (small)intestinal bacteria in personalized therapeutic approaches

Characterisation of two wood-waste and coffee bean husk biochars for the removal of micropollutants from water

The inclusion of bioaugmented low-cost biochar in current wastewater treatment technologies is a promising way to enhance the removal and degradation of emerging contaminants. In this paper, the properties of two wood waste biochars (wood waste mix - AB, and date palm fiber wood - PDF), and coffee bean husks (COF), produced at four temperatures (350, 450, 500, 550 degrees C) were compared, and investigated in the presence of Geobacter sulfurreducens or a mixed freshwater stream bacterial culture to understand their potential for the adsorption and biotransformation of two types of pesticides (thiacloprid, pirimicarb), and two pharmaceuticals (ibuprofen, diclofenac). Biochar yield was similar for all three biochars and ranged between 30 and 35%. The ash content of PDF and COF was significantly higher than AB. pH and electrical conductivity (EC) were initially high for COF (pH: 7.4-8; EC: 3-4.27 mS/cm) and PDF (pH: 7.7-10.1; EC: 4-6.24 mS/cm) after 24 h, but stabilized at neutral pH and <0.5 mS/cm EC after additional washes. COF and AB did not leach high concentrations of chloride (<10 mg/L), nitrate (<1 mg/L), nor sulphate (<76 mg/L), this in contrast to date palm fiber wood (PDF) with 1760 mg/L Cl- (550 degrees C), and 846 mg/L sulphate (350 degrees C). Lower pyrolysis temperatures reduced leachable anions. The biochars were highly (ultra)microporous with little meso- and macroporosity. The adsorption experiments showed that AB and COF biochars were both suited to sorb more than 90% of the initially spiked 10 ppm pirimicarb, AB removed 50.2% of the initial diclofenac concentration compared to only 5% for the no-biochar control, and both biochars could remove about 55% of the initially spiked thiacloprid, and 40% of the ibuprofen. In the presence of a mixed culture, on average 30% more thiacloprid and ibuprofen was removed from the supernatant by AB and COF than the sterile control. This work shows that selected wood-waste feedstocks and low pyrolysis temperature can produce environmentally-safe biochars that have suitable characteristics to sorb emergent pollutants from water. These materials could be further studied in multi-pollution sorption/competition experiments, and in larger environmental wastewater treatment systems

DataSheet1_Characterisation of Two Wood-Waste and Coffee Bean Husk Biochars for the Removal of Micropollutants from Water.docx

The inclusion of bioaugmented low-cost biochar in current wastewater treatment technologies is a promising way to enhance the removal and degradation of emerging contaminants. In this paper, the properties of two wood waste biochars (wood waste mix - AB, and date palm fiber wood - PDF), and coffee bean husks (COF), produced at four temperatures (350, 450, 500, 550°C) were compared, and investigated in the presence of Geobacter sulfurreducens or a mixed freshwater stream bacterial culture to understand their potential for the adsorption and biotransformation of two types of pesticides (thiacloprid, pirimicarb), and two pharmaceuticals (ibuprofen, diclofenac). Biochar yield was similar for all three biochars and ranged between 30 and 35%. The ash content of PDF and COF was significantly higher than AB. pH and electrical conductivity (EC) were initially high for COF (pH: 7.4–8; EC: 3–4.27 mS/cm) and PDF (pH: 7.7–10.1; EC: 4–6.24 mS/cm) after 24 h, but stabilized at neutral pH and − (550°C), and 846 mg/L sulphate (350°C). Lower pyrolysis temperatures reduced leachable anions. The biochars were highly (ultra)microporous with little meso- and macroporosity. The adsorption experiments showed that AB and COF biochars were both suited to sorb more than 90% of the initially spiked 10 ppm pirimicarb, AB removed 50.2% of the initial diclofenac concentration compared to only 5% for the no-biochar control, and both biochars could remove about 55% of the initially spiked thiacloprid, and 40% of the ibuprofen. In the presence of a mixed culture, on average 30% more thiacloprid and ibuprofen was removed from the supernatant by AB and COF than the sterile control. This work shows that selected wood-waste feedstocks and low pyrolysis temperature can produce environmentally-safe biochars that have suitable characteristics to sorb emergent pollutants from water. These materials could be further studied in multi-pollution sorption/competition experiments, and in larger environmental wastewater treatment systems.</p