Synthesis, Characterization of Low Molecular Weight Chitosan Selenium Nanoparticles and Its Effect on DSS-Induced Ulcerative Colitis in Mice.

Selenium nanoparticles have attracted extensive attention due to their good bioavailability and activity. In the present study, a new form of selenium nanoparticle (Low molecular weight chitosan selenium nanoparticles (LCS-SeNPs)) were synthesized in a system of sodium selenite and acetic acid. The size, element state, morphology and elementary composition of LCS-SeNPs were characterized by using various spectroscopic and microscopic measurements. The protection of LCS-SeNPs against dextran sulfate sodium (DSS)-induced intestinal barrier dysfunction and the inherent mechanisms of this process were investigated. The results showed that LCS-SeNPs, with an average diameter of 198 nm, zero-valent and orange-red relatively uniform spherical particles were prepared. LCS-SeNPs were mainly composed of C, N, O and Se elements, of which Se accounted for 39.03% of the four elements C, N, O and Se. LCS-SeNPs reduced colon injury and inflammation symptoms and improved intestinal barrier dysfunction. LCS-SeNPs significantly reduced serum and colonic inflammatory cytokines TNF-α and IL-6 levels. Moreover, LCS-SeNPs remarkably increased antioxidant enzyme GSH-Px levels in serum and colonic tissue. Further studies on inflammatory pathways showed that LCS-SeNPs alleviated DSS-induced colitis through the NF-κB signaling pathway, and relieved inflammatory associated oxidative stress through the Nrf2 signaling pathway. Our findings suggested that LCS-SeNPs are a promising selenium species with potential applications in the treatment of oxidative stress related inflammatory intestinal diseases.

[Evaluating fatigue resistance effect of health food by near-infrared tissue oximeter].

Currently, chronic fatigue syndrome (CFS) seriously affects people's normal living and work. In the present paper, the physiological parameters, such as tissue oxygenation saturation and heart rate, were used to evaluate the subjects' fatigue degree, and the fatigue resistance capsule and coffee were taken as a measure to adjust the fatigue. Human tissue oxygen saturation (rSO2) can be monitored noninvasively and in real time by near infrared spectroscopy (NIRS) based on spatially-resolved spectroscopy. Aiming at those brainworkers who need to work in an office for a long time; two static experiments were designed to evaluate the fatigue degree of the subjects who either take the fatigue resistance capsules/coffee or not. The rSO2 and heart rate (HR) of the subjects in the experiment group and contrast group were measured respectively for fatigue evaluation. This work particularly analyzed the changes in rSO2 in these two groups. The results show that the rSO2 of subjects in the experiment group evidently increased compared to that in the contrast group when the subjects took the fatigue resistance capsule or coffee, thereby show that the health food can reduce the fatigue to a certain extent.

[Optimally designing the probe of the near infrared oximeter to detect human tissue oxygen saturation non-invasively].

Human tissue oxygen saturation (rSO2) can be monitored non-invasively and in real time by near infrared spectroscopy (NIRS) based on spatially-resolved spectroscopy. To expand the clinical applications of the NIRS oximeter developed by our group based on the above principle, the accuracy of rSO2 must be ensured and enhanced as far as possible. In the present paper, the influences of the probe configuration, especially the distance between the detectors and the wavelength discreteness of the light source, on the accuracy of rSO2 were discussed. The results indicate that (1) to obtain rSOz accurately, two detectors need to be used, where the distance between them should be in the range of 5-20 mm and they should be both at least 20 mm apart from the light source; (2) there can be significant error in rSO2 (> 10%) induced by the discreteness of the two emission wavelengths especially the shorter one of the light source, so the real emission wavelengths must be accurately measured and the corresponding extinction coefficients of deoxygenated and oxygenated hemoglobin (Hb and HbO2) must be used in order to avoid this error. The above conclusions can be the guidance to optimally design the probe, which has been achieved in our NIRS oximeter.

Electrowetting of the blood droplet on the hydrophobic film of the EWOD chips.

Electrowetting-on-dielectric (EWOD) is a new method for handling droplets on the microfluidic chips. A most promising application for EWOD chips is the clinical diagnostics on human physiological fluids. This paper uses pure blood of rabbit as the experimental sample to test the wettability of the fluorocarbon polymer (p-C:F) hydrophobic layer of the EWOD chips. The contact angle variation of the blood droplet is observed, which provides the possibility of pure blood driven on the chips of p-C:F film. Forty multiple magnification images of the blood droplet are acquired by delicate experiments and the contact angles are calculated based on image processing technology. The electrowetting of the blood droplets on the EWOD chips is analyzed and the experimental results are in good agreement with the theoretical calculation.