Blood vessel-on-a-chip models aim at reproducing vascular functions. However, very few efficient methods have been designed to address the need for biological replicates in medium- to high-throughput screenings. Here, vessels-on-chip were designed in polydimethylsiloxane-glass chips using the viscous finger patterning technique which was adapted to create channels with various internal diameters inside a collagen solution and to simultaneously seed cells. This method was refined to create blood vessels composed of two concentric, distinct, and closely appositioned layers of human endothelial and perivascular cells arranged around a hollow lumen. These approaches allowed the formation of structurally correct blood vessels-on-chips which were constituted of either only endothelial cells or of both cell types in order to distinguish the vascular barrier reactivity to drugs in the presence or not of perivascular cells. The established vessels showed a tight vascular barrier, as assessed by immunostaining of the adherens junctions, and were reactive to the natural vasopermeant thrombin and to inflammatory cytokines. The presence of perivascular cells markedly increased the tightness of the vascular barrier and lowered its response to thrombin. The design allowed us to simultaneously challenge in real-time several tens of 3D-reconstituted, multicellular blood vessels in a standard multiwell plate format suitable for high-throughput drug screening.

Background: Drug incompatibility is defined as a physical-chemical reaction between two or more injectable drugs and that results mainly in precipitation or insolubility. Several strategies for reducing incompatibilities have been implemented empirically in intensive care units. However, these strategies have never been compared directly (and particularly in terms of the particulate load and drug mass flow rate) under standardized conditions. The objective of the present in vitro study was to evaluate the impact of various strategies for preventing incompatibility between simultaneously infused vancomycin and piperacillin/tazobactam. Methods: An in-line filter, a dilute vancomycin solution (5 mg/mL), and an alternative saline administration line were evaluated separately. The infusion line outlet was connected to a dynamic particle counter. The antibiotic concentration was measured in an HPLC-UV assay. Result: The use of an in-line filter and an alternative saline administration route did not significantly reduce the particulate load caused by vancomycin-piperacillin/tazobactam incompatibility. Dilution of the vancomycin solution was associated with a significantly lower particulate load and maintenance of the vancomycin mass flow rate. Discussion: It is important to systematically compare the efficacy of strategies for preventing drug incompatibility. The use of diluted vancomycin solution gave the best results in the case of vancomycin-piperacillin/tazobactam incompatibility.

Background Extracellular matrix (ECM) is a three-dimensional (3D) structure found around cells in the tissues of many organisms. It is composed mainly of fibrous proteins, such as collagen and elastin, and adhesive glycoproteins, such as fibronectin and laminin—as well as proteoglycans, such as hyaluronic acid. The ECM performs several essential functions, including structural support of tissues, regulation of cell communication, adhesion, migration, and differentiation by providing biochemical and biomechanical cues to the cells. Pancreatic β-cells have been previously shown to be responsive to the surrounding mechanical stress, impacting their insulin-secreting function. Purpose We aimed to derive a physiologically relevant in vitro model of pancreatic tissue by using an innovative synthesised porous ECM that mimics the native tissue microenvironment and mechanical properties. Methods Here we performed mechanical, physico-chemical and functional characterisation of a synthetic hydrogel ECM, composed of hyaluronic acid cross-linked with collagen types I and VI and modified with fibronectin. The hydrogel was used as a 3D cell culture scaffold for the MIN6 insulinoma cell line. Cell proliferation, viability, gene expression, and insulin secretion in response to glucose stimulus were assessed and contrasted with classic monolayer culture. Results The biomaterial exhibited a shear modulus of 815.37 kPa and a distinctive viscoelastic response. MIN6 cells showed a higher proliferation and viability rates and maintained insulin secretion in response to glucose stimulus and β-cell identity gene expression when cultured in the 3D hydrogel compared to monolayer culture. Conclusion Our study demonstrated the potential of this biomimetic hydrogel scaffold as an innovative matrix enabling better in vitro models to study disease physiopathology.

Introduction: Drug incompatibilities are among the most common medication errors in intensive care units. A precipitate can form and block the catheter or cause an adverse event in the patient. Intensive care units have implemented various strategies for limiting the occurrence of these incompatibilities, which have already been studied in vitro under standardized conditions. The objective of the present in vitro study was to continue these assessments by determining the impact of the infusion line geometry and the drugs’ position in the infusion set-up on the prevention of vancomycin–piperacillin/tazobactam incompatibility. Methods: Infusion lines with a different common volume, a multilumen medical infusion device, a dilute vancomycin solution, and separate infusions of incompatible drugs were evaluated separately. The infusion line outlet was connected to a dynamic particle counter. Results: Reducing the common volume, using multilumen medical devices, or spacing out the two incompatible drugs on the infusion line did not prevent the occurrence of a significant particulate load. Only dilution of the vancomycin solution was associated with a significantly lower particulate load and the absence of drug incompatibility. Conclusions: Our results show that under specific conditions, it is possible to reduce particulate contamination considerably.

Metastatic cancer cells and immune cells spread throughout the body via the bloodstream, reaching target sites for immune clearance or establishing secondary tumors in distant organs. As they move from blood circulation to a targeted organ, cells adhere to activated endothelium and then extravasate through it into a tissue-rich environment. The molecular mechanisms that drive the extravasation of immune and cancer cells are not yet fully understood. Most importantly, the phenotypic state identity of the disseminated cancer cells has yet to be characterized. While various sealed microfluidic devices have been developed to study extravasation, few, if any, allow for the efficient collection of extravasated cells. To address this limitation, we designed a biomimetic microfluidic device comprising a network of 3D blood capillaries and a customizable collecting chamber, separated by a porous membrane. Our device enables (i) real-time monitoring of cell extravasation through the endothelium via live imaging and (ii) the collection of disseminated cells for subsequent molecular characterization. We validated the functional properties of the 3D endothelial layer under shear stress and inflammation induction. After injecting promyeloblast cells and metastatic cancer cells into the lumen of the capillary network, we observed cell rolling and extravasation under continuous flow conditions. Finally, we collected extravasated cancer cells for gene expression profiling by real time–quantitative polymerase chain reaction. Overall, our novel microfluidic device reconstitutes a functional 3D blood vessel network, allowing real-time observation of extravasation and the collection of disseminated cells for further characterization.

Metabolic labeling techniques allow the incorporation of bioorthogonal reporters into glycans, enabling the targeted bioconjugation of molecular dyes within cells through click and bioorthogonal chemistry. Metabolic oligosaccharide engineering (MOE) has attracted considerable interest due to the essential role of glycosylation in numerous biological processes that involve molecular recognition and its impact on pathologies ranging from cancer to genetic disorders to viral and bacterial infections. Although MOE is better known for the detection of cell surface glycoconjugates, it is also a very important methodology for the study of intracellular glycans in physiological and pathological contexts. Such studies greatly benefit from high spatial resolution. However, super-resolution microscopy is not readily available in most laboratories and poses challenges for daily implementation. Expansion microscopy is a recent alternative that enhances the resolution of microscopy by physically enlarging biological specimens labeled with fluorescent markers. By embedding the sample in a swellable gel and causing it to expand isotropically through chemical treatment, subcellular structures can be visualized with enhanced precision and resolution without the need for super-resolution techniques. In this work, we illustrate the capacity of expansion microscopy to visualize intracellular sialylated glycans through the combined use of MOE and click chemistry. Specifically, we propose a procedure for bioorthogonal labeling and expansion microscopy that employs a reporter targeting sialylation, which may be associated with immunofluorescence for co-localization studies. This protocol enables localization studies of sialoconjugate biosynthesis, intracellular trafficking, and recycling.