4D Printing of Shape Memory Polymers: From Macro to Micro

A novel and versatile shape memory ink system allowing 4D printing with light at the macroscale as well as the microscale is presented. Digital light processing (DLP) and direct laser writing (DLW) are selected as suitable 3D printing technologies to cover both regimes. First, a system based on monofunctional isobornyl acrylate and two crosslinkers consisting of a soft and a hard diacrylate is identified and proven to be compatible with both printing techniques. Employing DLP, a large variety of structures exhibiting distinct complexity is printed. These structures range from simple frames to more demanding 3D geometries such as double platform structures, infinity rings, or cubic grids. The shape memory effect is demonstrated for all the 3D geometries. Excellent shape fixity as well as recovery and repeatability is shown. Furthermore, the formulation is adapted for fast 4D printing at the microscale using DLW. Importantly, the 4D printed microstructures display remarkable shape memory properties. The possibility of trapping and releasing microobjects, such as microspheres, is ultimately demonstrated by designing, smart box-like 4D microstructures that can be thermally actuated—evidencing the versatility and potential of the reported system

Impact of Aspirin Intake on Postoperative Survival after Primary Pancreatic Resection of Pancreatic Ductal Adenocarcinoma—A Single-Center Evaluation

(1) Background: The intake of aspirin (ASS) has been demonstrated to have a relevant impact on the pathogenesis, incidence and outcome in different solid gastrointestinal tumors. However, data on the effect of ASS on the short-term outcome and the long-term survival in patients with pancreatic carcinoma are still limited. (2) Methods: A total of 213 patients who underwent primary resection of PDAC at the University Hospital of Erlangen from January 2000 to December 2018 were included in this retrospective single-center study in total. Patients were stratified according to the aspirin intake into three groups: continuous aspirin intake (cASS), perioperatively interrupted aspirin intake (iASS) and no aspirin intake (no ASS) at the timepoint of surgery. The postoperative outcome as well as long-term survival were compared between the groups. (3) Results: There were no differences regarding postoperative morbidity (iASS: 54% vs. cASS: 53% vs. no ASS: 64%, p = 0.448) and in-hospital mortality (iASS: 4% vs. cASS: 10% vs. no ASS: 3%, p = 0.198) between the groups. The overall survival (OS) and disease-free survival (DFS) did not differ in the groups when comparing the ASS-intake status (OS: iASS 17.8 months vs. cASS 19.6 months vs. no ASS 21.6 months, p = 0.489; DFS: iASS 14.0 months vs. cASS 18.3 months vs. no ASS 14.7 months, p = 0.957). Multivariate analysis revealed that age (hazard ratio (HR) 2.2, p < 0.001), lymph node-positive status (HR 2.0, p < 0.001), R status 1 or 2 (HR 2.8, p < 0.001) and differentiation with a grading of 3 (HR 1.7, p = 0.005) were significant independent prognostic factors regarding the OS. Moreover, age (HR 1.5, p = 0.040), lymph node-positive status (HR 1.8, p = 0.002) and high-grade (G3) carcinomas (HR 1.5, p = 0.037) could be identified as independent prognostic parameters for DFS. (4) Conclusions: In patients undergoing primary surgery for curative resection of pancreatic carcinoma, the perioperative intake of ASS had no significant impact on postoperative outcome, overall and disease-free survival

Covalent Adaptable Microstructures via Combining Two‐Photon Laser Printing and Alkoxyamine Chemistry: Toward Living 3D Microstructures

Manufacturing programmable materials, whose mechanical properties can be adapted on demand, is highly desired for their application in areas ranging from robotics, to biomedicine, or microfluidics. Herein, the inclusion of dynamic and living bonds, such as alkoxyamines, in a printable formulation suitable for two-photon 3D laser printing is exploited. On one hand, taking advantage of the dynamic covalent character of alkoxyamines, the nitroxide exchange reaction is investigated. As a consequence, a reduction of the Young´s Modulus by 50%, is measured by nanoindentation. On the other hand, due to its “living” characteristic, the chain extension becomes possible via nitroxide mediated polymerization. In particular, living nitroxide mediated polymerization of styrene results not only in a dramatic increase of the volume (≈8 times) of the 3D printed microstructure but also an increase of the Young\u27s Modulus by two orders of magnitude (from 14 MPa to 2.7 GPa), while maintaining the shape including fine structural details. Thus, the approach introduces a new dimension by enabling to create microstructures with dynamically tunable size and mechanical properties

Exosomal ROR1 in peritoneal fluid identifies peritoneal disseminated PDAC and is associated with poor survival

BackgroundPancreatic ductal adenocarcinoma (PDAC) is one of the deadliest forms of cancer and peritoneal dissemination is one major cause for this poor prognosis. Exosomes have emerged as promising biomarkers for gastrointestinal cancers and can be found in all kinds of bodily fluids, also in peritoneal fluid (PF). This is a unique sample due to its closeness to gastrointestinal malignancies. The receptor tyrosine kinase-like orphan receptor 1 (ROR1) has been identified as a potential biomarker in human cancers and represents a promising target for an immunotherapy approach, which could be considered for future treatment strategies. Here we prospectively analyzed the exosomal surface protein ROR1 (exo-ROR1) in PF in localized PDAC patients (PER-) on the one hand and peritoneal disseminated tumor stages (PER+) on the other hand followed by the correlation of exo-ROR1 with clinical-pathological parameters.MethodsExosomes were isolated from PF and plasma samples of non-cancerous (NC) (n = 15), chronic pancreatitis (CP) (n = 4), localized PDAC (PER-) (n = 18) and peritoneal disseminated PDAC (PER+) (n = 9) patients and the surface protein ROR1 was detected via FACS analysis. Additionally, soluble ROR1 in PF was analyzed. ROR1 expression in tissue was investigated using western blots (WB), qPCR, and immunohistochemistry (IHC). Exosome isolation was proven by Nano Tracking Analysis (NTA), WB, Transmission electron microscopy (TEM), and BCA protein assay. The results were correlated with clinical data and survival analysis was performed.ResultsPDAC (PER+) patients have the highest exo-ROR1 values in PF and can be discriminated from NC (p &lt;0.0001), PDAC (PER-) (p &lt;0.0001), and CP (p = 0.0112). PDAC (PER-) can be discriminated from NC (p = 0.0003). In plasma, exo-ROR1 is not able to distinguish between the groups. While there is no expression of ROR1 in the exocrine pancreatic tissue, PDAC and peritoneal metastasis show expression of ROR1. High exo-ROR1 expression in PF is associated with lower overall survival (p = 0.0482).ConclusionWith exo-ROR1 in PF we found a promising diagnostic and prognostic biomarker possibly discriminating between NC, PDAC (PER-) and PDAC (PER+) and might shed light on future diagnostic and therapeutic concepts in PDAC

Metalfiber based 3-dimensional electrical current collectors for ultra-thick battery electrodes

The development of innovative technologies often requires fundamental new materials properties of individual components. In the present work, metastable metal fibers with unique mechanical and thermodynamic properties as well as crystallographic characteristics were linked to form mechanically stable, elastic 3-dimensional networks without changing the geometry, physical and thermodynamic properties of the fibers. The metal fiber networks have been used in lithium-ion battery technology as 3-dimensional current collectors, fundamentally improving battery technology. Worldwide there is an urgent need for improved battery technologies which are more ecological and economical. The metal fibers produced by a Melt spinning process are based on a copper silicon alloy. The basic physical and thermodynamic properties as well as the crystallographic state of the metal fibers were first quantified. The metal fibers had a length of several centimeters, a width of 10-100 micrometers, and a thickness of 2-10 micrometers. The mechanical properties were quantified as a function of metal fiber dimension, crystallographic and thermodynamic state. In particular, the thermodynamic metastable phase was shown to be instrumental for linking the metal fibers. During the metal fiber fabrication process, the molten metal is cooled and solidified within a few milliseconds. As a result, the crystalline structure at room temperature is not in a thermodynamic equilibrium, the stored energy of which was determined. A permanent linkage of the metal fibers was successfully implemented by cold and warm sintering of the fibers without affecting the basic geometry and partly the physical as well as thermodynamic properties of the fibers. Low activation of atomic diffusion by means of mechanically built-up pressure or temperature resulted in a linkage preferentially at the contact points between fibers. The reason for this is the crystallographic energy stored in the fibers during quenching of the molten metal. The 3-dimensional metal fiber networks were investigated in terms of their suitability as electrical current conductors in lithium-ion batteries. In particular, this work focused on improving the mechanical and electrical properties of lithium-ion batteries, which are the basis for a variety of processes in batteries. In principle, the 3-dimensional metal fiber networks enabled the fabrication of functional super-thick battery electrodes, which have a significantly increased surface capacitance of greater than 8 mAh cm-1

Impact of Patient Age on Postoperative Short-Term and Long-Term Outcome after Pancreatic Resection of Pancreatic Ductal Adenocarcinoma

(1) Purpose: to evaluate the impact of age on postoperative short-term and long-term outcomes in patients undergoing curative pancreatic resection for PDAC. (2) Methods: This retrospective single-center study comprised 213 patients who had undergone primary resection of PDAC from January 2000 to December 2018 at the University Hospital of Erlangen, Germany. Patients were stratified according the age into two groups: younger (&le;70 years) and older (&gt;70 years) patients. Postoperative outcome and long-term survival were compared between the groups. (3) Results: There were no significant differences regarding inhospital morbidity (58% vs. 67%, p = 0.255) or inhospital mortality (2% vs. 7%, p = 0.073) between the two groups. The median overall survival (OS) and disease-free survival (DFS) were significantly shorter in elderly patients (OS: 29.2 vs. 17.1 months, p &lt; 0.001, respectively; DFS: 14.9 vs. 10.4 months, p = 0.034). Multivariate analysis revealed that age was a significant independent prognostic predictor for OS and DFS (HR 2.23, 95% CI 1.58&ndash;3.15; p &lt; 0.001 for OS and HR 1.62, 95% CI 1.17&ndash;2.24; p = 0.004 for DFS). (4) Conclusion: patient age significantly influenced overall and disease-free survival in patients with PDAC undergoing primary resection in curative intent

Somatic Copy-Number Alterations in Plasma Circulating Tumor DNA from Advanced EGFR-Mutated Lung Adenocarcinoma Patients

Background: To assess the clinical relevance of genome-wide somatic copy-number alterations (SCNAs) in plasma circulating tumor DNA (ctDNA) from advanced epidermal growth factor receptor (EGFR)-mutated lung adenocarcinoma patients. Methods: We included 43 patients with advanced EGFR T790M-positive lung adenocarcinoma who were treated with osimertinib after progression under previous EGFR-TKI therapy. We performed genomic profiling of ctDNA in plasma samples from each patient obtained pre-osimertinib and after patients developed resistance to osimertinib. SCNAs were detected by shallow whole-genome plasma sequencing and EGFR mutations were assessed by droplet digital PCR. Results: SCNAs in resistance-related genes (rrSCNAs) were detected in 10 out of 31 (32%) evaluable patients before start of osimertinib. The presence of rrSCNAs in plasma before the initiation of osimertinib therapy was associated with a lower response rate to osimertinib (50% versus 81%, p = 0.08) and was an independent predictor for shorter progression-free survival (adjusted HR 3.33, 95% CI 1.37–8.10, p = 0.008) and overall survival (adjusted HR 2.54, 95% CI 1.09–5.92, p = 0.03). Conclusions: Genomic profiling of plasma ctDNA is clinically relevant and affects the efficacy and clinical outcome of osimertinib. Our approach enables the comprehensive assessment of SCNAs in plasma samples of lung adenocarcinoma patients and may help to guide genotype-specific therapeutic strategies in the future