Post-surgical chemotherapy in pancreatic cancer has notorious side effects due to the high dose required. Multiple devices have been designed to tackle this aspect and achieve a delayed drug release. This study aimed to explore the controlled and sustained local delivery of a reduced drug dose from an irinotecan-loaded electrospun nanofiber membrane (named TARTESSUS) that can be placed on the patients' tissue after tumor resection surgery. The drug delivery system formulation was made of polycaprolactone (PCL). The mechanical properties and the release kinetics of the drug were adjusted by the electrospinning parameters and by the polymer ratio between 10 w.t.% and 14 w.t.% of PCL in formic acid:acetic acid:chloroform (47.5:47.5:5). The irinotecan release analysis was performed and three different release periods were obtained, depending on the concentration of the polymer in the dissolution. The TARTESSUS device was tested in 2D and 3D cell cultures and it demonstrated a decrease in cell viability in 2D culture between 72 h and day 7 from the start of treatment. In 3D culture, a decrease in viability was seen between 72 h, day 7 (p < 0.001), day 10 (p < 0.001), 14 (p < 0.001), and day 17 (p = 0.003) as well as a decrease in proliferation between 72 h and day 10 (p = 0.030) and a reduction in spheroid size during days 10 (p = 0.001), 14 (p < 0.001), and 17 (p < 0.001). In conclusion, TARTESSUS showed a successful encapsulation of a chemotherapeutic drug and a sustained and delayed release with an adjustable releasing period to optimize the therapeutic effect in pancreatic cancer treatment.

Mimicking the diffusion that drugs suffer through different body tissues before reaching their target is a challenge. In this work, a versatile membrane-based microfluidic platform was developed to allow for the identification of drugs that would keep their cytotoxic properties after diffusing through such a barrier. As an application case, this paper reports on a microfluidic device capable of mimicking the diffusion that free or encapsulated anticancer drugs would suffer in the intestine before reaching the bloodstream. It not only presents the successful fabrication results for the platform but also demonstrates the significant effect that the analyzed drugs have over the viability of osteosarcoma cells. This intestine-like microfluidic platform works as a tool to allow for the identification of drugs whose cytotoxic performance remains effective enough once they enter the bloodstream. Therefore, it allows for the prediction of the best treatment available for each patient in the battle against cancer.

The use of lipid nanoparticles as biodegradable shells for controlled drug delivery shows promise as a more effective and targeted tumor treatment than traditional treatment methods. Although the combination of target therapy with nanotechnology created new hope for cancer treatment, methodological issues during in vitro validation of nanovehicles slowed their application. In the current work, the effect of methotrexate (MTX) encapsulated in different matrices was evaluated in a dynamic microfluidic platform. Effects on the viability of osteosarcoma cells in the presence of recirculation of cell media, free MTX and two types of blank and drug-containing nanoparticles were successfully assessed in different tumor-mimicking microenvironments. Encapsulated MTX was more effective than the equal dose free drug treatment, as cell death significantly increased under the recirculation of both types of drug-loaded nanoparticles in all concentrations. In fact, MTX-nanoparticles reduced cell population 50 times more than the free drug when 150-µM drug dose was recirculated. Moreover, when compared to the equivalent free drug dose recirculation, cell number was reduced 60 and 100 points more under recirculation of each nanoparticle with a 15-µM drug concentration. Thus, the results obtained with the microfluidic model present MTX-lipid nanoparticles as a promising and more effective therapy for pediatric osteosarcoma treatment than current treatment options. © 2021 by the authors. Licens

Limitations in effectiveness and the invasive nature of current cancer treatment options emphasize the need for further clinical advancements. Among other approaches, targeted hyperthermia is as a new strategy aimed at targeting cancerous cells to improve the efficacy of radiotherapy or cytotoxic drugs. However, the testing of magnetic vehicles has mainly focused on the use of nanoparticles. In this work, Fe77B10Si10C3 glass-coated amorphous magnetic microwires were assessed for the first time as magnetic vehicles with high potential for the localized heating of osteosarcoma cells by means of an AC magnetic field. The results from the in vitro assays performed inside a microfluidic device demonstrated the ability of these magnetic microwires to induce malignant cell death. Exposing the system to different magnetic fields for less than 1 h provoked a reduction up to 89% of the osteosarcoma cell population, whereas healthy myoblastoma cells remained nearly unaffected. The proposed technology demonstrates in vitro the effectiveness of these microwires as vehicles for targeted magnetic hyperthermia.

Highly migratory cancer cells often lead to metastasis and recurrence and are responsible for the high mortality rates in many cancers despite aggressive treatment. Recently, the migratory behavior of patient-derived glioblastoma multiforme cells on microtracks has shown potential in predicting the likelihood of recurrence, while at the same time, antimetastasis drugs have been developed which require simple yet relevant high-throughput screening systems. However, robust in vitro platforms which can reliably seed single cells and measure their migration while mimicking the physiological tumor microenvironment have not been demonstrated. In this study, we demonstrate a microfluidic device which hydrodynamically seeds single cancer cells onto stamped or femtosecond laser ablated polystyrene microtracks, promoting 1D migratory behavior due to the cells' tendency to follow topographical cues. Using time-lapse microscopy, we found that single U87 glioblastoma multiforme cells migrated more slowly on laser ablated microtracks compared to stamped microtracks of equal width and spacing (p < 0.05) and exhibited greater directional persistence on both 1D patterns compared to flat polystyrene (p < 0.05). Single-cell morphologies also differed significantly between flat and 1D patterns, with cells on 1D substrates exhibiting higher aspect ratios and less circularity (p < 0.05). This microfluidic platform could lead to automated quantification of single-cell migratory behavior due to the high predictability of hydrodynamic seeding and guided 1D migration, an important step to realizing the potential of microfluidic migration assays for drug screening and individualized medicine. Published under license by AIP Publishing.

Development of new targeted therapies is a challenge in the battle against cancer. Although a variety of treatments is currently available, there is no technique for rapidly evaluating the response of cancer patients to the drug. In this work, a microfluidic platform for the real-time simultaneous analysis of the success rate of different nanoparticle based chemotherapeutic drugs is presented. Based on a previous planar chamber and a reported sensitivity enhancing strategy, linear and cross shape microstructures were integrated into the chamber dome of the microfluidic polydimethylsiloxane and glass platform in order to provide a higher fluid mixing and treatment-cell interaction. Several methotrexate (MTX) based treatments (free MTX, MTX loaded Lecithin-PVA nanoparticles, MTX loaded Lecithin-Tween 80 nanoparticles) as well as their respective controls (cell media and both blank nanoparticles) were recirculated through the microchamber over an osteosarcoma cell monolayer. These nanovehicles reduced cell population to less than 20% (LEC-PVA nanoparticles) and 2.3% (LEC-Tween nanoparticles), demonstrating that nanoparticles are a promising target therapy for cancer treatment. Moreover, microstructured platforms demonstrated a higher efficacy in the drug-screening process: due to the liquid folding a higher amount of nanoparticles was internalized by the cells and, therefore, results were observed faster. In fact, the time required to reduce cell viability to the half was nearly a 75% faster. Furthermore, this microfluidic platform offers the capability to test up to five different drugs simultaneously, making it a powerful tool to evaluate the effect of multiple drugs and determine the most effective and personalized treatment.

Microfluidic devices are becoming mainstream tools to recapitulate in vitro the behavior of cells and tissues. In this study, we use microfluidic devices filled with hydrogels of mixed collagen-Matrigel composition to study the migration of lung cancer cells under different cancer invasion microenvironments. We present the design of the microfluidic device, characterize the hydrogels morphologically and mechanically and use quantitative image analysis to measure the migration of H1299 lung adenocarcinoma cancer cells in different experimental conditions. Our results show the plasticity of lung cancer cell migration, which turns from mesenchymal in collagen only matrices, to lobopodial in collagen-Matrigel matrices that approximate the interface between a disrupted basement membrane and the underlying connective tissue. Our quantification of migration speed confirms a biphasic role of Matrigel. At low concentration, Matrigel facilitates migration, most probably by providing a supportive and growth factor retaining environment. At high concentration, Matrigel slows down migration, possibly due excessive attachment. Finally, we show that antibody-based integrin blockade promotes a change in migration phenotype from mesenchymal or lobopodial to amoeboid and analyze the effect of this change in migration dynamics, in regards to the structure of the matrix. In summary, we describe and characterize a robust microfluidic platform and a set of software tools that can be used to study lung cancer cell migration under different microenvironments and experimental conditions. This platform could be used in future studies, thus benefitting from the advantages introduced by microfluidic devices: precise control of the environment, excellent optical properties, parallelization for high throughput studies and efficient use of therapeutic drugs.

Cancer is a leading cause of mortality in the world, with osteosarcoma being one of the most common types among children between 1 and 14 years old. Current treatments including preoperative chemotherapy, surgery and postoperative chemotherapy produce several side effects with limited effectiveness. The use of lipid nanoparticles as biodegradable shells for controlled drug delivery shows promise as a more effective and targeted tumor treatment. However, in vitro validation of these vehicles is limited due to fluid stagnation in current techniques, in which nanoparticles sediment onto the bottom of the wells killing the cells by asphyxiation. In the current series of experiments, results obtained with methotrexate-lipid nanoparticles under dynamic assay conditions are presented as a promising alternative to current free drug based therapies. Effects on the viability of the U-2 OS osteosarcoma cell line of recirculation of cell media, free methotrexate and blank and methotrexate containing lipid nanoparticles in a 11 mu M concentration were successfully assessed. In addition, several designs for the microfluidic platform used were simulated using COMSOL-Multiphysics, optimized devices were fabricated using soft-lithography and simulated parameters were experimentally validated. Nanoparticles did not sediment to the bottom of the platform, demonstrating the effectiveness of the proposed system. Moreover, encapsulated methotrexate was the most effective treatment, as after 72 h the cell population was reduced nearly 40% while under free methotrexate circulation the cell population doubled. Overall, these results indicate that methotrexate-lipid nanoparticles are a promising targeted therapy for osteosarcoma treatment.

Bacterial biofilms led to numerous problems in a wide variety of sectors as the medical environment, the food and water industry, or the naval sector. Completely developed biofilms are nearly impossible to eliminate due to the high antibiotic resistance these complex systems present. The lack of evidential indicators of their presence at the first stages of development makes antimicrobial treatments late and inadequate. Therefore, it is necessary to find new methods for the early detection of biofilm development in order to improve the efficiency of treatments by exposing bacterial cells before encapsulation in the extracellular matrix. For this purpose, this paper presents a real-time analysis of bacterial adhesion and biofilm growth by means of electrochemical measurements. Cyclic voltammetry and differential pulse voltammetry were performed with thin-film interdigitated microelectrode-based sensors. More sensitive and selective measurements were obtained with the second technique. Bacterial adhesion was detected 1 h after the initial inoculum, and three different redox centers were identified on bacterial surfaces. Finally, bacterial biofilm growth phases (lag, exponential, and stationary) were identified through the electrochemical measurements.

A surface sensor has been developed in order to record the cortical activity in animal models for neuro-science research. The device is made of gold on Cyclic Olefin Polymer (COP) and Cyclic Olefin Copolymer (COC) soft polymers using microsystems technology. The resulting system is flexible, customizable, bio-compatible, and fulfills reproducibility standards during the manufacturing process. Impedances are in the range of 100k Omega, thus making the system suitable for recording field potentials on the cortical surface. This paper explains the implementation process together with the implantation procedures and the results obtained in behaving rats. Results show that COP-based sensors are preferable to COC due to their higher flexibility and ease of manipulation. The versatility of COP polymers offers the possibility to adapt the electrode array to the cortical surface thus increasing surface of contact with the brain tissue. To validate the current approach, 8-contact sensors were implanted bilaterally over the motor cortices of awake, free moving rats. Cortical activity was evaluated on free moving animals and under the effect of different drugs. The quality and features of the recordings was in accordance with that of the current state of art systems thus demonstrating the feasibility of using COP-based systems for electrophysiological recordings in experimental investigation.

In this chapter we discuss the cell-free layer (CFL) developed adjacent to the wall of microgeometries containing complex features representative of the microcirculation, such as contractions, expansions, bifurcations and confluences. The microchannels with the different geometries were made of polydimethylsiloxane (PDMS) and we use optical techniques to evaluate the cell-free layer for red blood cells (RBCs) suspensions with different hematocrit (Hct). The images are captured using a high-speed video microscopy system and the thickness of the cell-free layer was measured using both manual and automatic image analysis techniques. The results show that in in vitro microcirculation, the hematocrit and the geometrical configuration have a major impact on the CFL thickness. In particular, the thickness of the cell-free layer increases as the fluid flows through a contraction¿expansion sequence and that this increase is enhanced for lower hematocrit. In contrast, the flow rates tested in these studies did not show a clear influence on the CFL thickness.

Iron oxide nanoparticles were developed using solvothermal synthesis and suspended in a physiological fluid constituted by erythrocytes in order to perform studies of flow behaviour in glass microchannels. The main purpose of this work was to study the influence of different iron oxide nanoparticles and magnetic fields in the plasma layer thickness and also the influence of the magnetic field in the area composed of nanoparticles attracted to the wall of the microchannel. The results obtained show that nanoparticles with magnetic characteristics promote the thinning of the plasma layer, in contrast to the behaviour observed with nanoparticles without magnetic characteristics. It was also observed upon application of magnetic fields with different intensities, the plasma layer tend to disappear in some areas depending on the type of particles. Moreover, the area of nanoparticles attracted to the microchannel wall increases with the increase of the magnetic field intensity.