Development and clinical validation of a microfluidic-based platform for CTC enrichment and downstream molecular analysis.

Background: Although many CTC isolation and detection methods can provide information on cancer cell counts, downstream gene and protein analysis remain incomplete. Therefore, it is crucial to develop a technology that can provide comprehensive information on both the number and profile of CTC. Methods: In this study, we developed a novel microfluidics-based CTC separation and enrichment platform that provided detailed information about CTC. Results: This platform exhibits exceptional functionality, achieving high rates of CTC recovery (87.1%) and purification (∼4 log depletion of WBCs), as well as accurate detection (95.10%), providing intact and viable CTCs for downstream analysis. This platform enables successful separation and enrichment of CTCs from a 4 mL whole-blood sample within 15 minutes. Additionally, CTC subtypes, selected protein expression levels on the CTC surface, and target mutations in selected genes can be directly analyzed for clinical utility using immunofluorescence and real-time polymerase chain reaction, and the detected PD-L1 expression in CTCs is consistent with immunohistochemical assay results. Conclusion: The microfluidic-based CTC enrichment platform and downstream molecular analysis together provide a possible alternative to tissue biopsy for precision cancer management, especially for patients whose tissue biopsies are unavailable.

Effect of 40 Hz light flicker on behaviors of adult C57BL/6J mice.

40 Hz light flicker can activate multiple brain regions of wild-type mice. However, there are no systematic studies on the behavioral effects of 40 Hz light flicker on wild-type mice. Adult wild-type C57BL/6J mice were treated with 40 Hz light flicker (200 lx, 40 Hz, 1 h/day for 3 weeks) to evaluate its effects on several behaviors, including mood, locomotor activity, memory, social interaction, mechanical pain, and sense of smell. In the open field test, the elevated zero-maze test, forced swimming test, and tail suspension test, 40 Hz mice showed no anxiety and depression-like behaviors. In the rotarod test, no differences were found between the anti-fatigue ability and motor coordination ability. In memory-related tests, 40 Hz mice showed the short-term cognitive enhancement in the novel object recognition test. Interestingly, 40 Hz mice showed no enhanced the long-term memory performance in the contextual fear conditioning test, and tone-cued fear conditioning test. Besides, 40 Hz mice increased their exploration of social cues that were unfamiliar to them and differed significantly from their own experiences. In terms of sensory abilities, 40 Hz mice had unchanged pain sensitivity in the von Frey fiber test and significant enhancement in the olfactory ability in the food-seeking test. In conclusion, this 40 Hz light stimulation paradigm has high safety and can improve the specific behavioral ability, which provides a theoretical basis for the future use of 40 Hz light flicker as a disease prevention or treatment method.

Characterization of the trophic transfer and fate of methylmercury in the food web of Zhalong Wetland, Northeastern China.

The transfer and fate of methylmercury (MeHg) in typical components, such as sediment, sediment-inhabiting animals, pelagic fish, and three large waterfowls, namely, red-crowned crane (Grus japonensis), mallard (Anas platyrhynchos), and oriental stork (Ciconia boyciana), of the ecosystem in China's Zhalong Wetland were examined using equivalence-based mass balance model. The biomagnification degree of MeHg increased on the species at the high trophic level of the system. Hence, elevated MeHg concentration (3.2 µg g-1, dry weight) was detected in the endangered G. japonensis. The accumulation of the organometal generally followed the decreasing order of oriental stork (carnivore) > mallard (omnivore) > red-crowned crane (omnivore). The predicted results of MeHg at each node of the food web were generally in accordance with the measured values (F = 0.09, P = 0.78), implying that the model is suitable for the prediction of MeHg fate in the inland aquatic system. According to the model, the respiration for the species at low trophic strata was the key input source of MeHg, but ingestion played an important role for MeHg intake in the species at the high trophic position in the food web. Metabolism was a crucial pathway of MeHg loss for the top predators in the ecosystem.

Regeneration of cortical tissue from brain injury by implantation of defined molecular gradient of semaphorin 3A.

Despite great efforts in the exploration of therapeutic strategies for treating brain injuries, it is still challenging to regenerate neural tissues and to restore the lost function within an injured brain. In this report, we employed a tissue engineering approach to regenerate cortical tissue from brain injury by implantation of defined semaphorin 3A (Sema3A) gradient packaged in a hydrogel based device. Over a thirty-day recovery period, the implanted Sema3A gradient was sufficient to induce substantial migration of neural progenitor cells to the hydrogel and to promote differentiation of these cells for neuroregeneration at the injury site. As revealed by molecular characterization and RNA transcriptome analysis, the regenerated tissues induced by Sema3A gradient exhibited significant similarity to normal cortical tissues. Many genes associated with neuronal migration and stem cell differentiation were significantly up-regulated. In addition, our result suggested a crosstalk between Sema3A and Wnt/ß-catenin pathways in course of induced brain regeneration. This study demonstrated an innovative strategy to regenerate brain tissue after traumatic injury by controlling the in vivo chemotactic environment with unprecedented sophistication, and also resolved new insights about Sema3A's role in adult neurogenesis.

Core-Shell-Shell Upconversion Nanoparticles with Enhanced Emission for Wireless Optogenetic Inhibition.

Recent advances in upconversion technology have enabled optogenetic neural stimulation using remotely applied optical signals, but limited success has been demonstrated for neural inhibition by using this method, primarily due to the much higher optical power and more red-shifted excitation spectrum that are required to work with the appropriate inhibitory opsin proteins. To overcome these limitations, core-shell-shell upconversion nanoparticles (UCNPs) with a hexagonal phase are synthesized to optimize the doping contents of ytterbium ions (Yb3+) and to mitigate Yb-associated concentration quenching. Such UCNPs' emission contains an almost three-fold enhanced peak around 540-570 nm, matching the excitation spectrum of a commonly used inhibitory opsin protein, halorhodopsin. The enhanced UCNPs are utilized as optical transducers to develop a fully implantable upconversion-based device for in vivo tetherless optogenetic inhibition, which is actuated by near-infrared (NIR) light irradiation without any electronics. When the device is implanted into targeted sites deep in the rat brain, the electrical activity of the neurons is reliably inhibited with NIR irradiation and restores to normal level upon switching off the NIR light. The system is further used to perform tetherless unilateral inhibition of the secondary motor cortex in behaving mice, achieving control of their motor functions. This study provides an important and useful supplement to the upconversion-based optogenetic toolset, which is beneficial for both basic and translational neuroscience investigations.

Tetherless near-infrared control of brain activity in behaving animals using fully implantable upconversion microdevices.

Many nanomaterials can be used as sensors or transducers in biomedical research and they form the essential components of transformative novel biotechnologies. In this study, we present an all-optical method for tetherless remote control of neural activity using fully implantable micro-devices based on upconversion technology. Upconversion nanoparticles (UCNPs) were used as transducers to convert near-infrared (NIR) energy to visible light in order to stimulate neurons expressing different opsin proteins. In our setup, UCNPs were packaged in a glass micro-optrode to form an implantable device with superb long-term biocompatibility. We showed that remotely applied NIR illumination is able to reliably trigger spiking activity in rat brains. In combination with a robotic laser projection system, the upconversion-based tetherless neural stimulation technique was implemented to modulate brain activity in various regions, including the striatum, ventral tegmental area, and visual cortex. Using this system, we were able to achieve behavioral conditioning in freely moving animals. Notably, our microscale device was at least one order of magnitude smaller in size (∼100 µm in diameter) and two orders of magnitude lighter in weight (less than 1 mg) than existing wireless optogenetic devices based on light-emitting diodes. This feature allows simultaneous implantation of multiple UCNP-optrodes to achieve modulation of brain function to control complex animal behavior. We believe that this technology not only represents a novel practical application of upconversion nanomaterials, but also opens up new possibilities for remote control of neural activity in the brains of behaving animals.