Winsteadqvist1372

In this work, we developed a facile end-functionalization method using hydroxylated coumarin to initiate the ring-opening polymerization of cyclic esters to synthesize a series of fluorescent biodegradable aliphatic polyesters with tailorable properties. The resulting fluorescent functionalized poly(l-lactide) (PLLA-COU), poly(ε-caprolactone) (PCL-COU) poly(δ-valerolactone) (PVL-COU) and poly(trimethylene carbonate) (PTMC-COU) were investigated to evaluate the dependence of fluorescence on the chemical structure and molecular weight of the materials. The differences in the electron withdrawing ability and the density of ester groups are responsible for the changes in the fluorescence quantum yield. https://www.selleckchem.com/products/jw74.html Then, two representative biodegradable materials, namely, PLLA-COU and PCL-COU, were used to prepare fluorescent paclitaxel-loaded microspheres. During in vitro drug release, the release rate of the PCL-COU microspheres is dramatically faster than that of the PLLA-COU microspheres due to the difference in the material nature and their surface morphologies, possibly achieving a tunable degradation and release rate for the drug carriers. Fluorescent functionalized polyester microspheres can retain their fluorescence properties and emit bright blue light for fluorescence tracing during the degradation process. Biological evaluations showed that both fluorescent polyesters are devoid of any significant toxicity and have good biocompatibility. The results demonstrated that the obtained fluorescent polyesters are promising for use in traceable and controlled drug delivery with tunable drug release.Developing efficient methods for the real-time detection of Zn2+ levels in biological systems is highly relevant to improving our understanding of the role of Zn2+ in the progression of Parkinson's disease (PD). In this work, a novel Schiff base based Zn2+ fluorescent probe (ZP) was designed, synthesized and systematically investigated. A significant turn-on effect on ZP upon the addition of Zn2+ was observed, accompanied by a blue-shift of the fluorescence spectra. ZP is sensitive to Zn2+ and has excellent selectivity against various biologically relevant cations, anions and amino acids. The sensing mechanism of ZP was studied by 1H NMR, MS, single crystal X-ray diffraction and theoretical calculations. The results showed that the response of ZP to Zn2+ was based on the chelation-hydrolysis-enhancement process. Upon bonding, Zn2+ hydrolyzes the Schiff base to an aldehyde precursor, the resulting aldehyde further coordinates to Zn2+ to form a more stable heterobimetallic complex leading to the emission enhancement and blue-shift. ZP was applied to imaging exogenous/endogenous Zn2+ in live HeLa cells. Furthermore, we successfully measured the Zn2+ levels using in vitro PD models, which provided a visualization method to better understand the relationship between Zn2+ levels and PD development.Photothermal therapy (PTT) has emerged as one of the promising methodologies for the treatment of cancer, and ideal photothermal agents need to be biodegradable and have strong optical absorbance in the near-infrared (NIR) optical window. Here, we report a new phthalocyanine molecule, 4OCSPC, which expands the absorbance edge to 850 nm. Under 808 nm NIR laser irradiation, 4OCSPC polymeric micelles showed robust photostability and a high photothermal conversion of 47.0%. Also, the 4OCSPC polymeric micelles exhibit a high in vivo PTT efficacy against 4T1 tumors in mice.The existence of nonspecific protein adsorption often results in significant challenges for microfluidic devices and laboratory cultureware used in biological experiments. Developing antifouling surfaces is thus increasingly desired by microfluidics engineers and biologists. Our previous studies have demonstrated that ionic hydrogen bonding between free ε-NH2 groups of the alkaline amino acids in proteins and surface negatively charged groups plays a critical role in strong adsorption of proteins onto the solid surfaces. Thus, the current work presents a facile and universal surface modification method based on self-assembly of oligopeptides with a sequence of Ala-Lys-Ala-Lys-Ala-Lys-Ala-Lys (AK-VIII) on poly(dimethylsiloxane) (PDMS) and polystyrene (PS) surfaces under physiological pH conditions. The results show that AK-VIII can self-organize into a compact amphipathic β-sheet-rich coating layer on the PDMS and PS surfaces with similar coverage, which largely minimizes nonspecific adsorption of proteins. In addition, we compared the performances of BSA and AK-VIII used as blocking reagents to evaluate their inhibitory effect on nonspecific adsorption of the antigen and detection antibody in carcinoembryonic antigen (CEA) enzyme-linked immunosorbent assay (ELISA). The results showed that AK-VIII exhibits better performance than BSA for diminishing nonspecific adsorption of the antigen and detection antibody, thus providing lower background noise, a lower detection limit, and a wider linear range in CEA assays. This study provides a novel and versatile alternative for developing antifouling coatings to address nonspecific protein adsorption on both PDMS-based engineering and PS-based biological materials.The low loading and poor cycling performance of sulfur cathodes are among the critical barriers restricting the practical application of lithium-sulfur (Li-S) batteries. The rational design of composites consisting of transition metals and conductive nanocarbon is considered an effective strategy to construct cathode materials for Li-S batteries with excellent cycling stability and rate capability. Herein, we propose a spray drying method to fabricate 3D pomegranate-like titanium nitride (TiN)@graphene composites as hosts for sulfur cathodes. The hollow spheres are coated with graphene layers to form a shell, serving as a highly efficient electrochemical reaction chamber and a reservoir for polysulfides. The TiN@graphene/S electrode exhibits an excellent capacity of 810 mA h g-1 after 200 cycles at 0.5C. The cathodes with high areal sulfur loadings of 2.8 and 3.6 mg cm-2 maintained remarkable capacities of 568 and 515 mA h g-1, respectively, after 500 cycles. The TiN hollow spheres not only accommodate the large volume expansion of sulfur but also improve the conversion of polysulfides during the discharge/charge process.