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Recently, the polyion complex (PIC) micelle has been suggested as a promising carrier system for peptide and proteins. However, its utilities are limited by its sensitivity to the environment such as dilution and ionic strength of the solution. In this study, to overcome these obstructions, PIC micelles prepared from an anionic block copolymer, poly(ethylene glycol)-poly(alpha,beta-aspartic acid), and a cationic protein, trypsin, were cross-linked with glutaraldehyde through the Schiff base formation. On the basis of a light scattering technique, the results revealed an efficient resistance of the cross-linked PIC micelle to a high salt concentration, which was a key parameter controlling the structure of the PIC micelles. Moreover, the stability of trypsin after cross-linking was remarkably improved. Evidently, as a bionanoreactor and/or bionanoreservoir, the PIC micelles entrapping protein molecules in the cross-linked core reveal an improved stability, allowing their wide application in the fields of biotechnology and pharmaceutical sciences.

Background The outbreak of 2019 coronavirus disease (COVID-19) could increase the risk of depression. However, epidemiological data on outbreak-associated depressive morbidity of female adolescents are not available. This study determines the incidence and correlates of depression among female adolescents aged 11–18 years during the COVID-19 outbreak in mainland China. Methods A large cross-sectional sample, nationwide online survey was conducted during the COVID-19 outbreak. Depression was assessed using the Center for Epidemiologic Studies Depression Scale (CES-D), and the correlative factors of depression were analyzed. Results In this study, 4805 female adolescents were enrolled with a median (range) age of 15 (11–18) years. Of them, 1899 (39.5%) suffered from depression with a CES-D score of > 15. The onset of depression was significantly related to age, grade, distant learning, attitude toward COVID-19, sleep duration, and physical exercise duration. Furthermore, participants aged 15–18 years (OR = 1.755, 95% CI: 1.550–1.987, p < 0.001), participating in distant learning (OR = 0.710, 95% CI: 0.564–0.894, p = 0.004), concerned about COVID-19 (OR = 0.414, 95% CI: 0.212–0.811, p = 0.010), with sleep duration/day of < 6 h (OR = 2.603, 95% CI: 1.946–3.483, p < 0.001),and with physical exercise duration/day < 30 min (OR = 1.641, 95% CI: 1.455–1.850, p < 0.001) represented to be independent factors for suffering from depression. Conclusion During the COVID-19 outbreak, depression was common among female adolescents. Older age, distant learning, concern about COVID-19, short sleep duration, and physical exercise duration represented the independent factors for suffering from depression.

Synthetic biology provides an opportunity for the construction and exploration of alternative solutions to biological problems - solutions different from those chosen by natural life. To this end, synthetic biologists have built new sensory systems, cellular memories, and alternative genetic codes. There is a growing interest in applying synthetic approaches to multicellular systems, especially in relation to multicellular self-organization. Here we describe a synthetic biological system that confers large-scale de novo patterning activity on 2-D and 3-D populations of mammalian cells. Instead of using the reaction-diffusion mechanisms common in real embryos, our system uses cadherin-mediated phase separation, inspired by the known phenomenon of cadherin-based sorting. An engineered self-organizing, large-scale patterning system requiring no prior spatial cue may be a significant step towards the construction of self-assembling synthetic tissues.

Scaling in membrane distillation (MD) is a key issue in desalination of concentrated saline water, where the interface property between the membrane and the feed become critical. In this paper, a new slippery mechanism was explored as an innovative concept to understand the scaling behavior in membrane distillation for a soluble salt, NaCl. The investigation was based on a novel design of a superhydrophobic polyvinylidene fluoride (PVDF) membrane with micro-pillar arrays (MP-PVDF) using a micromolding phase separation (µPS) method. The membrane showed a contact angle of 166.0 ± 2.3° and the sliding angle of 15.8 ± 3.3°. After CF4 plasma treatment, the resultant membrane (CF4-MP-PVDF) showed a reduced sliding angle of 3.0 o. In direct contact membrane distillation (DCMD), the CF4-MP-PVDF membrane illustrated excellent anti-scaling in concentrating saturated NaCl feed. Characterization of the used membranes showed that scaling due to NaCl crystals and possible membrane wetting occurred on the control PVDF and MP-PVDF membranes, but not on the CF4-MP-PVDF membrane. To understand this phenomenon, a "slippery" theory was introduced and correlated the sliding angle to the slippery surface of CF4-MP-PVDF and its anti-scaling property. This work provides a well-defined physical and theoretical platform for investigating scaling problems in membrane distillation and beyond.

To improve the stability of lysozyme-incorporated polyion complex (PIC) micelles in physiological condition, three types of hydrophobic groups, including phenyl (Phe), naphthyl (Nap), and pyrenyl (Py) terminal groups, were separately introduced to the omega-end of poly(ethylene glycol)-poly(alpha,beta-aspartic acid) block copolymers (PEG-P(Asp)). The goal was to enhance association forces between the enzyme, lysozyme, and PEG-P(Asp) carriers. Introduction of these hydrophobic groups significantly decreases micellar critical association concentration and increases the micellar tolerability against increasing NaCl concentrations. Particularly, PIC micelles formed from PEG-P(Asp) with Py groups was most stable against increasing NaCl concentrations up to 0.1 M. Significant deviation from a spherical shape for the micelles was also observed for the PEG-P(Asp)-Py system, consistent with an increased association number.

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To create a high-performance immunoassay system based on a nanosphere/antibody complex, pentaethylenehexamine-ended poly(ethylene glycol), N6-PEG comprising N6-PEG-5k (M(n) = 6000 g/mol) and N6-PEG-2k (M(n) = 2000 g/mol) was employed as a novel blocking agent to modify the surface of nanospheres. Both the antibody (antiferritin) and the N6-PEG were covalently bonded onto the nanospheres by the linkage of their amino groups with the activated carboxyl groups of those particles. The quantification of antiferritin and tethered N6-PEG polymer was carried out using the copper reduction/bicinchoninic acid reaction (the Micro BCA method). Dynamic-light-scattering (DLS) and electrophoretic mobility (mu(e)) measurements were performed to characterize the nanosphere/antiferritin/N6-PEG complex, which was prepared under various conditions. Simultaneously, the immune response of the complex obtained in this manner was measured by the turbidimetric monitoring method in phosphate buffer (10 mM, pH = 7.4). On the basis of all the results, the optimum conditions for preparing an acceptable nanosphere/antiferritin/N6-PEG complex were determined. Interestingly, compared to the blocking treatment with bovine serum albumin (BSA), which is a well-known blocking agent, surface modification with N6-PEG, especially that using a mixture of N6-PEG-5k and N6-PEG-2k, improved the performance (increased immune response yield and decreased detection limit) of the nanosphere/antiferritin complex to a remarkable degree in both phosphate buffer and 100% fetal bovine serum (FBS), thus significantly demonstrating the potential of the nanosphere/antibody/mixed-PEG complex as central to a high-performance immunoassay system.