Flexible Toolbox of High-Precision Microfluidic Modules for Versatile Droplet-Based Applications.

Although the enormous potential of droplet-based microfluidics has been successfully demonstrated in the past two decades for medical, pharmaceutical, and academic applications, its inherent potential has not been fully exploited until now. Nevertheless, the cultivation of biological cells and 3D cell structures like spheroids and organoids, located in serially arranged droplets in micro-channels, has a range of benefits compared to established cultivation techniques based on, e.g., microplates and microchips. To exploit the enormous potential of the droplet-based cell cultivation technique, a number of basic functions have to be fulfilled. In this paper, we describe microfluidic modules to realize the following basic functions with high precision: (i) droplet generation, (ii) mixing of cell suspensions and cell culture media in the droplets, (iii) droplet content detection, and (iv) active fluid injection into serially arranged droplets. The robustness of the functionality of the Two-Fluid Probe is further investigated regarding its droplet generation using different flow rates. Advantages and disadvantages in comparison to chip-based solutions are discussed. New chip-based modules like the gradient, the piezo valve-based conditioning, the analysis, and the microscopy module are characterized in detail and their high-precision functionalities are demonstrated. These microfluidic modules are micro-machined, and as the surfaces of their micro-channels are plasma-treated, we are able to perform cell cultivation experiments using any kind of cell culture media, but without needing to use surfactants. This is even more considerable when droplets are used to investigate cell cultures like stem cells or cancer cells as cell suspensions, as 3D cell structures, or as tissue fragments over days or even weeks for versatile applications.

Intensive lipid-lowering therapy for early achievement of guideline-recommended LDL-cholesterol levels in patients with ST-elevation myocardial infarction ("Jena auf Ziel").

BACKGROUND AND AIMS: Currently, less than 20% of patients at very high-risk achieve ESC/EAS dyslipidemia guideline-recommended LDL-C target levels in Europe. "Jena auf Ziel-JaZ" is a prospective cohort study in which early combination therapy with atorvastatin 80 mg and ezetimibe 10 mg was initiated on admission in patients with ST-elevation myocardial infarction (STEMI) and lipid-lowering therapy was escalated during follow-up with bempedoic acid and PCSK9 inhibitors to achieve recommended LDL-C targets in all patients. Moreover, we evaluated side-effects of lipid-lowering therapy. METHODS: Patients admitted with STEMI at Jena University Hospital were started on atorvastatin 80 mg and ezetimibe 10 mg on admission. Patients were followed for EAS/ESC LDL-C target achievement during follow-up. RESULTS: A total of 85 consecutive patients were enrolled in the study. On discharge, 32.9% achieved LDL-C targets on atorvastatin 80 mg and ezetimibe 10 mg. After 4-6 weeks, 80% of all patients on atorvastatin 80 mg and ezetimibe started at the index event were on ESC/EAS LDL-C targets. In 20%, combined lipid-lowering therapy was escalated with either bempedoic acid or PCSK9 inhibitors. All patients achieved LDL-C levels of or below 55 mg/dL during follow-up on triple lipid-lowering therapy. Combined lipid-lowering therapy was well-tolerated with rare side effects. CONCLUSIONS: Early combination therapy with a high-intensity statin and ezetimibe and escalation of lipid-lowering therapy with either bempedoic acid or PCSK9 inhibitors gets potentially all patients with STEMI on recommended ESC/EAS LDL-C targets without significant side effects.

[Postoperative pain therapy after total knee arthroplasty : Is the local infiltration anesthesia the best therapy?] / Schmerz nach Knietotalendoprothese : Ist die lokale Infiltrationsanästhesie die beste Therapieoption?

BACKGROUND: Optimal perioperative pain management after total knee arthroplasty is necessary to promote mobilization and achieve early rehabilitation. The aim of this study was to determine whether local infiltration anesthesia (LIA) is the better postoperative pain therapy compared to a femoral nerve block (FNB) or a sciatic nerve block (SNB) using routine data. METHODS: Data from the acute pain registry "Qualitätsverbesserung in der postoperativen Schmerztherapie" (QUIPS) were analyzed. The endpoints included postoperative maximal pain, frequency of pain-related movement impairment, nausea, and number of patients requesting opioids postoperatively. The influence of regional anesthesia in addition to general anesthesia was analyzed in 5 groups. RESULTS: In total, the data of 8754 patients could be examined. It was found that the addition of LIA (ß = -0.087 p = 0.000) or FNB (ß = -0.137 p = 0.000) to general anesthesia is associated with a small but significant reduction of postoperative maximum pain. Between LIA, FNB, and SNB no relevant differences could be detected. DISCUSSION: The pain reduction achieved by adding LIA or FNB in patients after total knee arthroplasty is relatively small. Comparison of techniques is hindered as there exists no widely accepted standard for performing LIAs yet.

Parametric studies on droplet generation reproducibility for applications with biological relevant fluids.

Although the great potential of droplet based microfluidic technologies for routine applications in industry and academia has been successfully demonstrated over the past years, its inherent potential is not fully exploited till now. Especially regarding to the droplet generation reproducibility and stability, two pivotally important parameters for successful applications, there is still a need for improvement. This is even more considerable when droplets are created to investigate tissue fragments or cell cultures (e.g. suspended cells or 3D cell cultures) over days or even weeks. In this study we present microfluidic chips composed of a plasma coated polymer, which allow surfactants-free, highly reproducible and stable droplet generation from fluids like cell culture media. We demonstrate how different microfluidic designs and different flow rates (and flow rate ratios) affect the reproducibility of the droplet generation process and display the applicability for a wide variety of bio(techno)logically relevant media.

Generation of Cardiomyocytes in Pipe-Based Microbioreactor Under Segmented Flow.

BACKGROUND/AIMS: Embryonic stem (ES) cells have got a broad range differentiation potential. The differentiation is initiated via aggregation of non-differentiated ES cells into embryoid body (EB) capable of multi-lineage development. However experimental variables present in standard differentiation techniques lead to high EB heterogeneity, affecting development into the cells of desired lineage, and do not support the process automatization and scalability. METHODS: Here we present a novel pipe based microbioreactor (PBM) setup based on segmented flow, designed for spatial maintenance of temperature, nutrition supply, gas supply and sterility. RESULTS: We verified PBM feasibility for continuous process generating cardiac cells starting from single ES cell suspension followed by EB formation for up to 10 days. The ES cells used in the study were genetically modified for cardiac-specific EGFP expression allowing optical monitoring of cardiomyocytes while EBs remained within PBM for up to 10 days. Efficiency of cardiac cells formation within PBM was similar compared to a standard hanging drop based protocol. CONCLUSION: Our findings ensure further development of microfluidic bioreactor technology to enable robust cardiomyocytes production for needs of drug screening, tissue engineering and other applications.

A modular segmented-flow platform for 3D cell cultivation.

In vitro 3D cell cultivation is promised to equate tissue in vivo more realistically than 2D cell cultivation corresponding to cell-cell and cell-matrix interactions. Therefore, a scalable 3D cultivation platform was developed. This platform, called pipe-based bioreactors (pbb), is based on the segmented-flow technology: aqueous droplets are embedded in a water-immiscible carrier fluid. The droplet volumes range from 60 nL to 20 µL and are used as bioreactors lined up in a tubing like pearls on a string. The modular automated platform basically consists of several modules like a fluid management for a high throughput droplet generation for self-assembly or scaffold-based 3D cell cultivation, a storage module for incubation and storage, and an analysis module for monitoring cell aggregation and proliferation basing on microscopy or photometry. In this report, the self-assembly of murine embryonic stem cells (mESCs) to uniformly sized embryoid bodies (EBs), the cell proliferation, the cell viability as well as the influence on the cell differentiation to cardiomyocytes are described. The integration of a dosage module for medium exchange or agent addition will enable pbb as long-term 3D cell cultivation system for studying stem cell differentiation, e.g. cardiac myogenesis or for diagnostic and therapeutic testing in personalized medicine.