Advances in three-dimensional tumor models for colorectal cancer / 中华肿瘤杂志

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.

Point-of-care testing in the diagnosis of infectious diseases / 中华检验医学杂志

Rapid diagnosis is important for the prevention and control of infectious disease.Point-of-care testing (POCT) technology is simple,mobile,rapid,sensitive and accurate.In recent years,POCT has been widely used in the detection of infectious agents.This article reviews the development of POCT in the diagnosis of infectious diseases,focusing on immuno-chromatographic technology,microfluidic chip technology and loop-mediated isothermal amplification (LAMP) technology.

Design and application of a batch-reactor microfluidic device for synthesis of 18F PET tracers / 中华核医学与分子影像杂志

Objective To develop an automated control system of batch-reactor microfluidic device for the synthesis of PET tracers and to use it for the preparation of 18F-fluorodeoxyglucose (FDG).Methods The 18F microreactor was composed of polydimethylsiloxane (PDMS) microfluidic chip and customized glass microvessel integrated with stainless capillary tube as heater or cooler.PDMS chip was fabricated by silkscreen printing technology.The hardware control of digital and analog quantity of synthesizer was completed by organic integration programmable logic controller (PLC),micro air valve,temperature sensor,com pressed air source,direct current stabilized voltage source and vacuum pumps.The interface was designed using Kingyiew software.Thin-layer chromatography (TLC) was applied to measure the 18F-labeling yield and the radiochemical purity of 18F-FDG.Kryptofix (K2.2.2) content,residual acetonitrile content,traits,a septic and bacterial endotoxins levels were also tested.Results The size of the microfluidic device was 10 cm× 10 cm×15 cm.The size of the automated control system was similar to the desktop chassis.The amount of precursor used in the single synthesis of 18F-FDG was 2.5 mg.The radiochemical purity of 18F-FDG was higher than 95％,the labeling yield was (92.4± 1.4) ％ and the 18 F-FDG yield was (35.6± 5.6) ％ (decay corrected).The 18F-FDG product was clear and colorless,and the pH value was 6.2±0.4.The K2.2.2 con tent was less than 50 μg/g.The residual acetonitrile content was (12.8±2.6) μg/g.Both aseptic and bacte rial endotoxins tests were negative.Conclusions A batch-mode microfluidic device is developed and successfully applied to prepare 18F-FDG.It has the advantages of high integration,small size,less consumption of labeling precursor and easy programming.

Research progress on the radio-synthesis of PET probes in microfluidic chips / 中华核医学与分子影像杂志

Radio-synthesis of PET tracers in microfluidic chip system for imaging research could fa-cilitate synthesis and screening of radiotracer. Moreover, modular and multi-functional microfluidic chip syn-thesis system could realize the combination of functional modules, synthetic automation, system integration and improvement of radiochemical protection. In this review, research progress in microfluidic chip system for radio-synthesis of PET tracers has been summarized.

Fabrication of Polymerase Chain Reaction Plastic Lab-on-a-Chip Device for Rapid Molecular Diagnoses / 대한배뇨장애요실금학회지

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.

Saliva as a diagnostic tool

Salivary diagnostics is an emerging field that has progressed through several important developments in the past decade, including the publication of the human salivary proteome and the infusion of federal funds to integrate nanotechnologies and microfluidic engineering concepts into developing compact point-of-care devices for rapid analysis of this secretion. In this article, we discuss some of these developments and their relevance to the prognosis, diagnosis and management of periodontitis, as an oral target, and cardiovascular disease, as a systemic example for the potential of these biodiagnostics. Our findings suggest that several biomarkers are associated with distinct biological stages of these diseases and demonstrate promise as practical biomarkers in identifying and managing periodontal disease, and acute myocardial infarction. The majority of these studies have progressed through biomarker discovery, with the identified molecules requiring more robust clinical studies to enable substantive validation for disease diagnosis. It is predicted that with continued advances in this field the use of a combination of biomarkers in multiplex panels is likely to yield accurate screening tools for these diagnoses in the near future

Recent Progress in Lab-on-a-Chip Technology and Its Potential Application to Clinical Diagnoses / 대한배뇨장애요실금학회지

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 microfluidic 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 microfluidic 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.