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Harmful algal blooms (HABs) are common disastrous ecological anomalies in coastal waters. An effective algae monitoring approach is important for natural disaster warning and environmental governance. However, conducting rapid and sensitive detection of multiple algae is still challenging. Here, we designed an ultrasensitive, rapid and portable double-layer microfluidic biochip for the simultaneous quantitative detection of six species of algae. Specific DNA probes based on the 18S ribosomal DNA (18S rDNA) gene fragments of HABs were designed and labeled with the fluorescent molecule cyanine-3 (Cy3). The biochip had multiple graphene oxide (GO) nanosheets-based reaction units, in which GO nanosheets were applied to transfer target DNA to the fluorescence signal through a photoluminescence detection system. The entire detection process of multiple algae was completed within 45 min with the linear range of fluorescence recovery of 0.1 fM-100 nM, and the detection limit reached 108 aM. The proposed approach has a simple detection process and high detection performance and is feasible to conduct accurate detection with matched portable detection equipment. It will have promising applications in marine natural disaster monitoring and environmental care.

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Secreted proteins provide abundant functional information on living cells and can be used as important tumor diagnostic markers, of which profiling at the single-cell level is helpful for accurate tumor cell classification. Currently, achieving living single-cell multi-index, high-sensitivity, and quantitative secretion biomarker profiling remains a great challenge. Here, a high-throughput living single-cell multi-index secreted biomarker profiling platform is proposed, combined with machine learning, to achieve accurate tumor cell classification. A single-cell culture microfluidic chip with self-assembled graphene oxide quantum dots (GOQDs) enables high-activity single-cell culture, ensuring normal secretion of biomarkers and high-throughput single-cell separation, providing sufficient statistical data for machine learning. At the same time, the antibody barcode chip with self-assembled GOQDs performs multi-index, highly sensitive, and quantitative detection of secreted biomarkers, in which each cell culture chamber covers a whole barcode array. Importantly, by combining the K-means strategy with machine learning, thousands of single tumor cell secretion data are analyzed, enabling tumor cell classification with a recognition accuracy of 95.0%. In addition, further profiling of the grouping results reveals the unique secretion characteristics of subgroups. This work provides an intelligent platform for high-throughput living single-cell multiple secretion biomarker profiling, which has broad implications for cancer investigation and biomedical research.

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Biomarkers play an important role in disease diagnosis and prognosis, which demand reliable, sensitive, rapid, and economic detection platform to conduct simultaneous multiple-biomarkers analysis in serum or body liquid. Here, we developed a universal biosensing platform through integrating the advantages of unique nanostructure and biochemistry properties of graphene oxide quantum dots and high throughput and low cost of microfluidic chip for reliable and simultaneous detection of multiple cancer antigen and antibody biomarkers. The performance of the proposed biosensing platform is validated through the representative cancer biomarkers including carcino-embryonic antigen (CEA), carbohydrate antigen 125 (CA125), α-fetoprotein (AFP), carbohydrate antigen 199 (CA199) and carbohydrate antigen 153 (CA153). It has a large linear quantification detection regime of 5-6 orders of magnitude and an ultralow detection limit of 1 pg/mL or 0.01 U/mL. Moreover, the proposed biosensing chip is capable of conducting 5-20 kinds of biomarkers from at least 60 persons simultaneously in 40 min with only 2 µL serum of each patient, which essentially reduces the detection cost and time to at least 1/60 of current popular methods. Clinical breast cancer and healthy samples detection results indicated its promising perspective in practical applications including cancer early diagnosis, prognosis, and disease pathogenesis study.

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Non-invasive early diagnosis is of great significance in disease pathologic development and subsequent medical treatments, and microRNA (miRNA) detection has attracted critical attention in early cancer screening and diagnosis. High-throughput, sensitive, economic, and fast miRNA sensing platforms are necessary to realize the low-concentration miRNA detection in clinical diagnosis and biological studies. Here, we developed an attomolar-level ultrasensitive, rapid, and multiple-miRNA simultaneous detection platform enabled by nanomaterial locally assembled microfluidic biochips. This platform presents a large linear detection regime of 1 aM-10 nM, an ultralow detection limit of 0.146 aM with no amplification, a short detection time of 35 min with multiplex miRNA sensing capability, and a small sample volume consumption of 2 µL. The detection results of five miRNAs in real samples from breast cancer patients and healthy humans indicate its excellent capacity for practical applications in early cancer diagnosis. The proposed ultrasensitive, rapid, and multiple-miRNA detection microfluidic biochip platform is a universal miRNA detection approach and an important and valuable tool in early cancer screening and diagnosis as well as biological studies.

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The recent outbreak of coronavirus disease 2019 (COVID-19) is highly infectious, which threatens human health and has received increasing attention. So far, there is no specific drug or vaccine for COVID-19. Therefore, it is urgent to establish a rapid and sensitive early diagnosis platform, which is of great significance for physical separation of infected persons after rapid diagnosis. Here, we propose a colorimetric/SERS/fluorescence triple-mode biosensor based on AuNPs for the fast selective detection of viral RNA in 40 min. AuNPs with average size of 17 nm were synthesized, and colorimetric, surface enhanced Raman scattering (SERS), and fluorescence signals of sensors are simultaneously detected based on their basic aggregation property and affinity energy to different bio-molecules. The sensor achieves a limit detection of femtomole level in all triple modes, which is 160 fM in absorbance mode, 259 fM in fluorescence mode, and 395 fM in SERS mode. The triple-mode signals of the sensor are verified with each other to make the experimental results more accurate, and the capacity to recognize single-base mismatch in each working mode minimizes the false negative/positive reading of SARS-CoV-2. The proposed sensing platform provides a new way for the fast, sensitive, and selective detection of COVID-19 and other diseases.

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BACKGROUND: Abdominal pregnancy is a rare type of ectopic pregnancy. We describe here a case of ectopic pregnancy implanted under the surface of the diaphragm, presenting the particular features of imaging findings from ultrasound, computed tomography (CT) and magnetic resonance imaging (MRI). CASE SUMMARY: A 30-year-old woman presented with complaint of intermittent abdominal pain, that had begun 5 d earlier. She had no current or abnormal vaginal bleeding, and her serum human chorionic gonadotropin level (13372.08 IU/L) indicated pregnancy. Vaginal ultrasound showed a mixed echogenic mass in the right ovary. CT (plain) scan showed a curved high density mass beneath the subhepatic space. MRI scan showed a curved mixed signal, with restricted diffusion beneath the subhepatic space. Abdominal ultrasound demonstrated a mixed echogenic mass in the right lobe of the liver near the apex of the diaphragm, with a visible yolk sac and germ cell region with a bud. Subsequent laparoscopy visualized a dark red mass under the right diaphragm, which was resected completely. Histopathological examination of the resected mass confirmed an ectopic pregnancy. The recovery was swift and uneventful, and the patient was discharged to home. CONCLUSION: Ectopic pregnancy should be in the differential diagnostic workup (via multiple imaging modalities) of childbearing woman with unexplained abdominal pain.

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Gene detection has important applications in biology, biomedical engineering, clinical, environmental, and marine fields. Rapid, sensitive, and selective recognition of specific genes is essential in practical applications. In this study, we describe a facile and sensitive DNA sensing platform for specific and quantitative detection of Heterosigma akashiwo, which is one of the causative agents of red tides. Fast and sensitive detection is achieved by using chemically synthesized graphene oxide (GO) nanosheets. Probe DNA is designed according to the specific DNA fragments of harmful algae and labeled with fluorescent molecules FAM (fluorescein-based dye). GO nanosheet solution is made, in which the strong interaction between FAM-labeled probe and GO nanosheets keeps them in close proximity, facilitating the fluorescence quenching of the fluorophore by GO nanosheets. In the presence of a complementary target DNA, the FAM-labeled DNA probe and the target DNA hybridize and desorb from the surface of GO nanosheets, resulting in restoration of fluorophore fluorescence. The concentration of target DNA fragments is analyzed by the fluorescence intensity at ~ 520 nm with emission wavelength of 480 nm. The sensitive detecting platform achieved stable measurement of 1 pM specific genes from Heterosigma akashiwo. Our GO nanosheet-based DNA-sensing platform performs fast and sensitive detection of trace amount of DNA, and enables quantitative recognition of harmful algae, which has promising applications in real-time monitoring in the marine environment of red tide generative dynamics, allowing effective control, particularly in relation to marine aquaculture.

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Saxitoxin (STX) is one of the most important marine toxins which affects the safety of domestic water. Rapid, sensitive and selective recognition of STX is crucial in environment monitoring. Here, we demonstrate a facile and ultrasensitive colorimetric sensor based on gold nanoparticles (Au NPs) and aptamer (Au NPs-aptamer biosensor) for specific and quantitative detection of STX. The aptamer reacts specifically with STX, resulting in the aggregation of Au NPs and the color change of the Au NP solution. The lowest detection concentration of the colorimetric sensor is 10 fM (3 fg mL-1), and a good linear relationship (R 2 = 0.9852) between the absorbance ratio and STX concentrations (10 fM to 0.1 µM) indicates that our Au NPs-aptamer biosensor can be used for quantitative sensing of STX. The detection time of STX is 30 minutes, and the sensor is successfully applied in the specific detection of STX in seawater. The Au NP-aptamer biosensor shows great potential in practical applications to monitor environmental pollution, marine aquaculture pollution, and seafood safety.

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Due to the antibacterial resistance crisis, developing new antibacterials is of particular interest. In this study, we combined the antifungal drug amphotericin B with 50,520 different small molecule compounds obtained from the Chinese National Compound Library in an attempt to improve its efficacy against Candida albicans persister cells. To systematically study the antifungal effect of each compound, we utilized custom-designed high-throughput microfluidic chips. Our microfluidic chips contained microchannels ranging from 3 µm to 5 µm in width to allow Candida albicans cells to line up one-by-one to facilitate fluorescence-microscope viewing. After screening, we were left with 10 small molecule compounds that improved the antifungal effects of amphotericin B more than 30% against Candida albicans persister cells.

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