A novel design of microfluidic platform for metronomic combinatorial chemotherapy drug screening based on 3D tumor spheroid model

Microfluidics in High-Throughput Drug Screening: Organ-on-a-Chip and C. elegans-Based Innovations

The development of therapeutic interventions for diseases necessitates a crucial step known as drug screening, wherein potential substances with medicinal properties are rigorously evaluated. This process has undergone a transformative evolution, driven by the imperative need for more efficient, rapid, and high-throughput screening platforms. Among these, microfluidic systems have emerged as the epitome of efficiency, enabling the screening of drug candidates with unprecedented speed and minimal sample consumption. This review paper explores the cutting-edge landscape of microfluidic-based drug screening platforms, with a specific emphasis on two pioneering approaches: organ-on-a-chip and C. elegans-based chips. Organ-on-a-chip technology harnesses human-derived cells to recreate the physiological functions of human organs, offering an invaluable tool for assessing drug efficacy and toxicity. In parallel, C. elegans-based chips, boasting up to 60% genetic homology with humans and a remarkable affinity for microfluidic systems, have proven to be robust models for drug screening. Our comprehensive review endeavors to provide readers with a profound understanding of the fundamental principles, advantages, and challenges associated with these innovative drug screening platforms. We delve into the latest breakthroughs and practical applications in this burgeoning field, illuminating the pivotal role these platforms play in expediting drug discovery and development. Furthermore, we engage in a forward-looking discussion to delineate the future directions and untapped potential inherent in these transformative technologies. Through this review, we aim to contribute to the collective knowledge base in the realm of drug screening, providing valuable insights to researchers, clinicians, and stakeholders alike. We invite readers to embark on a journey into the realm of microfluidic-based drug screening platforms, fostering a deeper appreciation for their significance and promising avenues yet to be explored.

Local Microbubble Removal in Polydimethylsiloxane Microchannel by Balancing Negative and Atmospheric Pressures

Long-term experiments using organoids and tissues are crucial for drug development. Microfluidic devices have been regularly used in long-term experiments. However, microbubbles often form in these devices, and they may damage and starve cells. A method involving the application of negative pressure has been reported to remove microbubbles from microfluidic devices composed of polydimethylsiloxane; however, negative pressure affects the cells and tissues in microfluidic devices. In this study, a local microbubble removal method was developed using a microfluidic device with 0.5 mm thin polydimethylsiloxane sidewalls. The thin sidewalls counterbalanced the negative and atmospheric pressures, thereby localizing the negative pressure near the negatively pressurized chamber. Microbubbles were removed within 5 mm of the negatively pressurized chamber; however, those in an area 7 mm and more from the chamber were not removed. Using the local removal method, a long-term perfusion test was performed, and no contact was confirmed between the bubbles and the simulated tissue for 72 h.

Advanced lung organoids and lung-on-a-chip for cancer research and drug evaluation: a review

Lung cancer has become the primary cause of cancer-related deaths because of its high recurrence rate, ability to metastasise easily, and propensity to develop drug resistance. The wide-ranging heterogeneity of lung cancer subtypes increases the complexity of developing effective therapeutic interventions. Therefore, personalised diagnostic and treatment strategies are required to guide clinical practice. The advent of innovative three-dimensional (3D) culture systems such as organoid and organ-on-a-chip models provides opportunities to address these challenges and revolutionise lung cancer research and drug evaluation. In this review, we introduce the advancements in lung-related 3D culture systems, with a particular focus on lung organoids and lung-on-a-chip, and their latest contributions to lung cancer research and drug evaluation. These developments include various aspects, from authentic simulations and mechanistic enquiries into lung cancer to assessing chemotherapeutic agents and targeted therapeutic interventions. The new 3D culture system can mimic the pathological and physiological microenvironment of the lung, enabling it to supplement or replace existing two-dimensional culture models and animal experimental models and realize the potential for personalised lung cancer treatment.

Patient-derived organoids of lung cancer based on organoids-on-a-chip: enhancing clinical and translational applications

Lung cancer is one of the most common malignant tumors worldwide, with high morbidity and mortality due to significant individual characteristics and genetic heterogeneity. Personalized treatment is necessary to improve the overall survival rate of the patients. In recent years, the development of patient-derived organoids (PDOs) enables lung cancer diseases to be simulated in the real world, and closely reflects the pathophysiological characteristics of natural tumor occurrence and metastasis, highlighting their great potential in biomedical applications, translational medicine, and personalized treatment. However, the inherent defects of traditional organoids, such as poor stability, the tumor microenvironment with simple components and low throughput, limit their further clinical transformation and applications. In this review, we summarized the developments and applications of lung cancer PDOs and discussed the limitations of traditional PDOs in clinical transformation. Herein, we looked into the future and proposed that organoids-on-a-chip based on microfluidic technology are advantageous for personalized drug screening. In addition, combined with recent advances in lung cancer research, we explored the translational value and future development direction of organoids-on-a-chip in the precision treatment of lung cancer.

Therapeutic strategies for non-small cell lung cancer: Experimental models and emerging biomarkers to monitor drug efficacies

While new targeted therapies have considerably changed the treatment and prognosis of non-small cell lung cancer (NSCLC), they are frequently unsuccessful due to primary or acquired resistances. Chemoresistance is a complex process that combines cancer cell intrinsic mechanisms including molecular and genetic abnormalities, aberrant interactions within the tumor microenvironment, and the pharmacokinetic characteristics of each molecule. From a pharmacological point of view, two levers could improve the response to treatment: (i) developing tools to predict the response to chemo- and targeted therapies and (ii) gaining a better understanding of the influence of the tumor microenvironment. Both personalized medicine approaches require the identification of relevant experimental models and biomarkers to understand and fight against chemoresistance mechanisms. After describing the main therapies in NSCLC, the scope of this review will be to identify and to discuss relevant in vitro and ex vivo experimental models that are able to mimic tumors. In addition, the interests of these models in the predictive responses to proposed therapies will be discussed. Finally, this review will evaluate the involvement of novel secreted biomarkers such as tumor DNA or micro RNA in predicting responses to anti-tumor therapies.

An Integrated Pulsation-Free, Backflow-Free Micropump Using the Analog Waveform-Driven Braille Actuator

The widespread adoption of long-term organs-on-a-chip culture necessitates both active perfusions that mimic physiological flow conditions and minimization of the complexity of microfluidic system and fluid handling. In particular, flow in microtissue such as microvascular is free of pulsation and backflow. The refreshable Braille actuator-based integrated microfluidic system can be employed with simple microchannels and setups. However, due to high pulsatile flow and backflow, ordinary Braille-driven micropumps generate non-physiological flow conditions. We have described a simple method for creating steady flow employing Braille actuators driven with a high-voltage analog waveform, called “constant flow waveform”, without incorporating complicated structures into the microchannel or actuator. We determined the constant flow waveform by measuring volume change of microchannel caused by actuated Braille pins using a conventional fluorescent dye and microscope. Using the constant flow waveform, we demonstrated that a Braille-driven pump reduced pulsating flow by 79% and backflow by 63% compared to conventional Braille-driven pump. Furthermore, we demonstrated that a parallel pair of three-stranded pin pumps effectively eliminated backflow by driving two pumps with the constant flow waveform half-cycle shifted to each other. Moreover, by raising the driving frequency, we could increase the average flow rate to ~2× higher than previously reported flow rate of a typical Braille-driven micropump.

Microfluidic Biosensor-Based Devices for Rapid Diagnosis and Effective Anti-cancer Therapeutic Monitoring for Breast Cancer Metastasis

Breast cancer with unpredictable metastatic recurrence is the leading cause of cancer-related mortality. Early cancer detection and optimized therapy are the principal determining factors for increased survival rate. Worldwide, researchers and clinicians are in search of efficient strategies for the timely management of cancer progression. Efficient preclinical models provide information on cancer initiation, malignancy progression, relapse, and drug efficacy. The distinct histopathological features and clinical heterogeneity allows no single model to mimic breast tumor. However, engineering three-dimensional (3D) in vitro models incorporating cells and biophysical cues using a combination of organoid culture, 3D printing, and microfluidic technology could recapitulate the tumor microenvironment. These models serve to be preferable predictive models bridging the translational research gap in drug development. Microfluidic device is a cost-effective advanced in vitro model for cancer research, diagnosis, and drug assay under physiologically relevant conditions. Integrating a biosensor with microfluidics allows rapid real-time analytical validation to provide highly sensitive, specific, reproducible, and reliable outcomes. In this manner, the multi-system approach in identifying biomarkers associated with cancer facilitates early detection, therapeutic window optimization, and post-treatment evaluation.This chapter showcases the advancements related to in vitro breast cancer metastasis models focusing on microfluidic devices. The chapter aims to provide an overview of microfluidic biosensor-based devices for cancer detection and high-throughput chemotherapeutic drug screening.