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Conventional tumor culture models include two-dimensional tumor cell cultures and xenograft models. The former has disadvantages including lack of tumor heterogeneity and poor clinical relevance, while the latter are limited by the slow growth, low engraftment successful rate, and high cost. In recent years, in vitro three-dimensional (3D) tumor models have emerged as the tool to better recapitulate the spatial structure and the in vivo environment of tumors. In addition, they preserve the pathological and genetic features of tumor cells and reflect the complex intracellular and extracellular interactions of tumors, which have become a powerful tool for investigating the tumor mechanism, drug screening, and personalized cancer treatment. 3D tumor model technologies such as spheroids, organoids, and microfluidic devices are maturing. Application of new technologies such as co-culture, 3D bioprinting, and air-liquid interface has further improved the clinical relevance of the models. Some models recapitulate the tumor microenvironment, and some can even reconstitute endogenous immune components and microvasculature. In recent years, some scholars have combined xenograft models with organoid technology to develop matched in vivo/in vitro model biobanks, giving full play to the advantages of the two technologies, and providing an ideal research platform for individualized precision therapy for specific molecular targets in certain subtypes of tumors. So far, the above technologies have been widely applied in the field of colorectal cancer research. Our research team is currently studying upon the application of patient-derived tumor cell-like clusters, a self-assembly 3D tumor model, in guiding the selection of postoperative chemotherapy regimens for colorectal cancer. A high modeling success rate and satisfactory results in the drug screening experiments have been achieved. There is no doubt that with the advancement of related technologies, 3D tumor models will play an increasingly important role in the research and clinical practice of colorectal cancer. [ABSTRACT FROM AUTHOR]

New platforms are enabling radiochemistry to be carried out in tiny, microliter-scale volumes, and this capability has enormous benefits for the production of radiopharmaceuticals. These droplet-based technologies can achieve comparable or better yields compared to conventional methods, but with vastly reduced reagent consumption, shorter synthesis time, higher molar activity (even for low activity batches), faster purification, and ultra-compact system size. We review here the state of the art of this emerging direction, summarize the radiotracers and prosthetic groups that have been synthesized in droplet format, describe recent achievements in scaling up activity levels, and discuss advantages and limitations and the future outlook of these innovative devices. [ABSTRACT FROM AUTHOR]

Highlights • A fibre-optic sensing architecture for digital microfluidic devices is introduced and developed. • Multiple microdroplets can be sensed along row and column fibre-optic cables. • The fibre-optic sensing architecture is shown to be scalable through model and experimental results. Abstract This work introduces a fibre-optic sensing architecture for digital microfluidic devices. The fibre-optic sensing architecture relies on a change in the total internal reflection angle to detect the presence of microdroplets in contact with fibre-optic cables through lowered optical transmission. The architecture uses m parallel column fibre-optic cables orthogonally overlapped with n parallel row fibre-optic cables to provide the Cartesian coordinates of multiple microdroplets. This creates m × n microdroplet sensing positions, for high localization, with only m + n measurement points, for practical implementation. The contact times of advancing and receding microdroplets are measured using an experimental configuration of the architecture. These contact times are found to be within the acceptable time limitations for high-speed operation of the digital microfluidic device. Ultimately, the fibre-optic sensing architecture is experimentally demonstrated as a three by three architecture for the localization of multiple microdroplets. [ABSTRACT FROM AUTHOR]

Recently, the unique capability of three-dimensional (3D) printing strategy for patterning micro-sized features with complex 3D architectures in a single process has caught an ever increasing interest within the domain of lab-on-a-chip devices. In this review, the latest advances in the constucting development of 3D microfluidic devices with 3D printing technologies in analytical application were summed up. To begin with, the attractive properties of 3D printing technologies were described. Then, the principles of three mainly printing technologies were introduced in detail. The stimulating progress related to applications of 3D printed lab-on-a-chip devices was subsequently dealt with. Finally, the challenges and opportunities in regard to numerous aspects of 3D printing microfluidic system were discussed. It is believed that higher resolution, more user-frinendly operation endows 3D printed lab-on-a-chip devices with great potential academic and commercial value in on-site environmental monitoring, food safety, and other point-of-care assay. [ABSTRACT FROM AUTHOR]

Lab-on-a-chip devices have now-a-days become an important aspect of analytical/bioanalytical chemistry having wide range of applications including clinical diagnosis, drug screening, cell biology, environmental monitoring, food safety analysis etc. Conventional lab-on-a-chip devices generally employ chemicals that are not environmentally friendly and were commonly fabricated on hard plastic platform which are non-degradable and hence ignore the importance of green analytical chemistry. In today's scenario, it is highly imperative to protect our environment by using less toxic and environmentally friendly chemicals/solvents and biocompatible platforms. Accordingly, the present article comprehensively reviews on the various green aspects of lab-on-a-chip devices for analytical processes which aim at fabricating environmentally friendly and cost-effective downsized devices so that the risk factor at the user's end upon longer exposure as well as to the environment can be reduced. The decisive factors for the accomplishment of green aspects of lab-on-a-chip devices including sample preparation using lab-on-a-chip systems to minimize the amount of sample/solvents to few microliters only, substitution of harmful solvents with green alternatives, minimal waste generation or proper treatment of waste and biodegradable and biocompatible platforms for fabricating lab-on-a-chip devices have been discussed in details. Additionally, the challenges that may hinder their commercialization are also critically discussed. • Greenness of Lab on chip devices for analytical processes are highlighted. • Recent advances in development of green Lab on chip technologies are presented. • Analytical applications of green Lab on chip devices are summarized. • Challenges in commercialization of green Lab on chip devices are discussed. [ABSTRACT FROM AUTHOR]

Purpose: We aim to fabricate a thermoplastic poly(methylmethacrylate) (PMMA) Lab-on-a-Chip device to perform continuous-flow polymerase chain reactions (PCRs) for rapid molecular detection of foodborne pathogen bacteria. Methods: A miniaturized plastic device was fabricated by utilizing PMMA substrates mediated by poly(dimethylsiloxane) interfacial coating, enabling bonding under mild conditions, and thus avoiding the deformation or collapse of microchannels. Surface characterizations were carried out and bond strength was measured. The feasibility of the Lab-on-a-Chip device for performing on-chip PCR utilizing a lab-made, portable dual heater was evaluated. The results were compared with those obtained using a commercially available thermal cycler. Results: A PMMA Lab-on-a-Chip device was designed and fabricated for conducting PCR using foodborne pathogens as sample targets. A robust bond was established between the PMMA substrates, which is essential for performing miniaturized PCR on plastic. The feasibility of on-chip PCR was evaluated using Escherichia coli O157:H7 and Cronobacter condimenti, two worldwide foodborne pathogens, and the target amplicons were successfully amplified within 25 minutes. Conclusions: In this study, we present a novel design of a low-cost and high-throughput thermoplastic PMMA Lab-on-a-Chip device for conducting microscale PCR, and we enable rapid molecular diagnoses of two important foodborne pathogens in minute resolution using this device. In this regard, the introduced highly portable system design has the potential to enable PCR investigations of many diseases quickly and accurately. [ABSTRACT FROM AUTHOR]

Introduction: Nowadays, on-a-chip capillary electrophoresis is a routine method for the detection of PCR fragments. The Agilent 2100 Bioanalyzer was one of the first commercial devices in this field. Our project was designed to study the characteristics of Agilent DNA 1000 kit in PCR fragment analysis as a part of circulating tumour cell (CTC) detection technique. Despite the common use of this kit a complex analysis of the results from a long-term project is still missing. Materials and methods: A commercially available Agilent DNA 1000 kit was used as a final step in the CTC detection (AdnaTest) for the determination of the presence of PCR fragments generated by Multiplex PCR. Data from 30 prostate cancer patients obtained during two years of research were analyzed to determine the trueness and precision of the PCR fragment size determination. Additional experiments were performed to demonstrate the precision (repeatability, reproducibility) and robustness of PCR fragment concentration determination. Results: The trueness and precision of the size determination was below 3% and 2% respectively. The repeatability of the concentration determination was below 15%. The difference in concentration determination increases when Multiplex-PCR/storage step is added between the two measurements of one sample. Conclusions: The characteristics established in our study are in concordance with the manufacturer's specifications established for a ladder as a sample. However, the concentration determination may vary depending on chip preparation, sample storage and concentration. The 15% variation of concentration determination repeatability was shown to be partly proportional and can be suppressed by proper normalization. [ABSTRACT FROM AUTHOR]

We report the fabrication of truly rectangular buried microchannels of record lengths in fused silica, using a novel femtosecond laser irradiation geometry, at 1030 nm, followed by chemical etching in hot KOH alone. As the result of a judicious choice of the laser parameters and writing geometry, an effective chemical etching rate of 500 μm per hour in the laser irradiated region is achieved, competing with the traditional and hazardous HF based etching, and faster than all earlier reports with KOH. This has resulted in the longest reported (6 mm) rectangular, microchannels, in a record etching time of 6 h. Linear and Cross microchannels have been fabricated with mean surface roughness less than 200 nm of the sidewalls. These results have been validated using an optical microscope, SEM and AFM imaging. The use of fused silica, the much eased safety concerns with KOH, the simplicity of our method, together with the enhanced ability to image from the top surface of smooth, rectangular, buried micro-channels, will motivate microfluidics for Optofluidic lab-on-chip applications, especially for biomedical diagnostics. • HF-free, safe etching using hot KOH alone. • Effective etching rate of 500 μm/h, fastest reported till date. • Great reduction in the channel fabrication time (Laser writing time). • Channel width from 50 μm to 500 μm, all in 6 h. • Mean side wall surface roughness <200 nm. • Validation using Optical imaging, SEM and AFM. [ABSTRACT FROM AUTHOR]

We present the construction of the lab-on-a-chip (LOC) system, a state-of-the-art technology that uses polymer materials (i.e., poly[dimethylsiloxane]) for the miniaturization of conventional laboratory apparatuses, and show the potential use of these microfuidic devices in clinical applications. In particular, we introduce the independent unit components of the LOC system and demonstrate how each component can be functionally integrated into one monolithic system for the realization of a LOC system. In specific, we demonstrate microscale polymerase chain reaction with the use of a single heater, a microscale sample injection device with a disposable plastic syringe and a strategy for device assembly under environmentally mild conditions assisted by surface modification techniques. In this way, we endeavor to construct a totally integrated, disposable microfuidic system operated by a single mode, the pressure, which can be applied on-site with enhanced device portability and disposability and with simple and rapid operation for medical and clinical diagnoses, potentially extending its application to urodynamic studies in molecular level. [ABSTRACT FROM AUTHOR]

Abstract: This article reviews recent developments on magnetoresistive detection of magnetic beads or nanoparticles by nanoscale sized sensors. Sensors are analyzed from an experimental and a numerical point of view in respect to their capability to either localize the position of a single magnetic particle or to detect the number of particles in a certain range. Guidelines are shown up on how to extend single sensors to sensor arrays with very high spatial resolution and how to modify the sensor shape in order to provide long distance measurements. Further, sensors in biological lab-on-a-chip environments are discussed. The magnetic ratchet and a gravitation based microfluidic component are reviewed as important tools to position and, therefore, detect biological components in continuous-flow devices. [ABSTRACT FROM AUTHOR]

Thermal optofluidics is an emerging field that promises to create numerous research and application opportunities in biophysics, biochemistry, and clinical biology. Innovation in plasmonic optics has led to the development of various invaluable tools in the fields of biosensing and microfluidic manipulation. The optothermal effect originates from light–matter interactions during photon–phonon conversion, which can lead to micro‐ or nanoscale inhomogeneities in the thermal distribution. This further induces a series of hydrodynamic phenomena such as natural convection, Marangoni convection, thermophoresis, the electrolyte Seebeck effect, depletion forces, and interfacial effects in colloidal particles. Light–matter interactions are particularly important for three aspects of microfluidics, namely the motion of colloidal particles, fluidic actuation, and biochemical reactions. This review first systematically elucidates the role of both nanoscale plasmonic thermal generation and heat‐induced fluidic motion in optofluidic microsystems. Then, recent state‐of‐the‐art thermal optofluidic applications of the above‐listed three aspects are presented. The paper aims to provide an insightful reference for future research in optofluidic biochemical systems. [ABSTRACT FROM AUTHOR]