17β-estradiol (17β-E2) plays a critical role in regulating reproduction in human, there is therefore an urgent need to detect it sensitively and precisely in a cost-effective and easy method. In this paper, a label-free integrated microfluidic paper-based analytical device was developed for highly sensitive electrochemical detection of 17β-E2. The microfluidic channel of the paper-based sensor was fabricated with wax printing and the three electrodes, including working, counter and reference electrode were screen-printed. Multi-walled carbon nanotubes (MWCNTs)/ thionine (THI)/ gold nanoparticles (AuNPs) Nano composites were synthesized and coated on screen-printed working electrode (SPWE) for the immobilization of anti-E2. In this electro-chemical system of paper-based immunoassay, THI molecules serving as an electrochemical mediator while MWCNTs and AuNPs, due to their excellent electrical conductivities, could accelerate electron transfer for the signal amplification. Experimental results revealed that the immunoassay is able to detect 17β-E2 as low as 10 pg mL-1, with a linear range from 0.01 to 100 ng mL-1. This microfluidic paper-based immunosensor would provide a new platform for low cost, sensitive, specific, and point-of-care diagnosis of 17β-E2.

Doxorubicin (DOX) is the most clinically important antibiotic in cancer treatment, but its severe cardiotoxicity and other side effects limit its clinical use. Therefore, monitoring DOX concentrations during therapy is essential to improve efficacy and reduce adverse effects. Here, we fabricated a sensitive electrochemical aptasensor for DOX detection. The sensor used gold wire as the working electrode and was modified with reduced graphene oxide (rGO)/gold nanoparticles (AuNPs) to improve the sensitivity. An aptamer was used as the recognition element for the DOX. The 5′ end of the aptamer was modified with a thiol group, and thus immobilized to the AuNPs, and the 3′ end was modified with methylene blue, which acts as the electron mediator. The combination between the aptamer and DOX would produce a binding-induced conformation, which changes the electron transfer rate, yielding a current change that correlates with the concentration of DOX. The aptasensor exhibited good linearity in the DOX concentration range of 0.3 μM to 6 μM, with a detection limit of 0.1 μM. In addition, the aptasensor was used for DOX detection in real samples and results, and showed good recovery. The proposed electrochemical aptasensor will provide a sensitive, fast, simple, and reliable new platform for detecting DOX.

Depression is a common and severely debilitating neuropsychiatric disorder. Multiple studies indicate a strong correlation between the occurrence of immunological inflammation and the presence of depression. The basolateral amygdala (BLA) is crucial in the cognitive and physiological processing and control of emotion. However, due to the lack of detection tools, the neural activity of the BLA during depression is not well understood. In this study, a microelectrode array (MEA) based on the shape and anatomical location of the BLA in the brain was designed and manufactured. Rats were injected with lipopolysaccharide (LPS) for 7 consecutive days to induce depressive behavior. We used the MEA to detect neural activity in the BLA before modeling, during modeling, and after LPS administration on 7 consecutive days. The results showed that after LPS treatment, the spike firing of neurons in the BLA region of rats gradually became more intense, and the local field potential power also increased progressively. Further analysis revealed that after LPS administration, the spike firing of BLA neurons was predominantly in the theta rhythm, with obvious periodic firing characteristics appearing after the 7 d of LPS administration, and the relative power of the local field potential in the theta band also significantly increased. In summary, our results suggest that the enhanced activity of BLA neurons in the theta band is related to the depressive state of rats, providing valuable guidance for research into the neural mechanisms of depression.

Peripheral blood leukocytes (PBLs) are the main source of DNA in blood samples. A common protocol is to store buffy coat specimens for future DNA isolation, and such samples may remain in frozen storage for years. However, the currently available methods to maintain buffy coat specimens can be optimized for better quality and cost efficiency. Seventeen donors (aged 24-34 years) were enrolled in this study. Initially, five centrifugal speeds were chosen to examine the distribution of PBLs in the cell layer; the buffy coat was then harvested to evaluate the cell quantity and viability after storing at 4°C for various times. Finally, the buffy coat was isolated, snap frozen, and kept at -80°C for 1 hour, 1 week, or 4 weeks until the DNA was extracted. Agarose gel electrophoresis and multiplex PCR were used to verify DNA integrity and amplifiability. There was a linear positive correlation between the amount of fresh PBLs and the DNA yield. At least 70% of PBLs were collected in the uppermost 40% of the cellular material when the centrifugal force was over 800 g compared to 400 g. Storing blood at 4°C for no more than 24 hours did not have an effect on the amount of PBLs or their viability. In addition, the amount of extracted DNA was decreased in the frozen buffy coat that was stored for more than 7 days, though the DNA quality was acceptable. DNA should be extracted from fresh buffy coat samples as soon as possible after collection, especially for very important samples. Retaining the upper 40% of the cell pack of blood instead of whole blood could improve the storage efficiency of biobanking such samples. Our study provides a recommended option for blood collection and processing protocols in biobanking.