A mesothelin microsensor based on an embedded thionine electronic medium within an imprinted polymer on an acupuncture needle electrode.

An electrochemical microsensor for mesothelin (MSLN) based on an acupuncture needle (AN) was constructed in this work. To prepare the microsensor, MSLN was self-assembled on 4-mercaptophenylboronic acid (4-MPBA) by an interaction force between the external cis-diol and phenylboronic acid. This was followed by the gradual electropolymerization of thionine (TH) and eriochrome black T (EBT) around the anchored protein. The thickness of the surface imprinted layers influenced the sensing performance and needed to be smaller than the height of the anchored protein. The polymerized EBT was not electrically active, but the polymerized TH provided a significant electrochemical signal. Therefore, electron transfer smoothly proceeded through the eluted nanocavities. The imprinted nanocavities were highly selective toward MSLN, and the rebinding of insulating proteins reduced the electrochemical signal of the embedded pTH. The functionalized interface was characterized by SEM and electrochemical methods, and the preparation conditions were studied. After optimization, the sensor showed a linear response in the range of 0.1 to 1000 ng mL-1 with a detection limit of 10 pg mL-1, indicating good performance compared with other reported methods. This microsensor also showed high sensitivity and stability, which can be attributed to the fine complementation of the imprinted organic nanocavities. The sensitivity of this sensor was related to the nanocavities used for electron transport around the AuNPs. In the future, microsensors that can directly provide electrochemical signals are expected to play important roles especially on AN matrices.

Endothelial Cell Migration on Poly(ε-caprolactone) Nanofibers Coated with a Nanohybrid Shish-Kebab Structure Mimicking Collagen Fibrils.

Regulating cell migration dynamics is of significance in tissue engineering and regenerative medicine. A 3D scaffold was created to provide various topographies based on a poly(ε-caprolactone) (PCL) self-induced nanohybrid shish-kebab structure, which consisted of aligned PCL nanofibers and spaced PCL crystal lamellae grown on the fibers. Electrospinning was applied followed by self-induced crystallization. The results resembled natural collagen fibrils in an extracellular matrix. This variable microstructure enabled control of cell adhesion and migration. The kebab size was controlled by initial PCL concentrations. The geometry of cells seeded on the fibers was less elongated, but the adhesion was more polarized with a higher nuclear shape index and faster migration speed. These results could aid in rapid endothelialization in tissue engineering.

Structure and properties of chlorogenic acid-loaded polylactide fiber prepared by melt spinning.

Polylactide/chlorogenic acid (PLA/CGA) blends with different weight ratios were prepared by melt mixing, and corresponding PLA/CGA fibers were produced via a two-step melt spinning process. For PLA/CGA blends, CGA was distributed uniformly in the PLA matrix. The intermolecular interactions between CGA and PLA existed. The viscosity of PLA/CGA blends was much lower than that of neat PLA. With the increase of CGA content, the viscosity of PLA/CGA blends decreased. As the CGA content increased, the crystallinity of both PLA/CGA blends and fibers decreased. In addition, the tensile strength of PLA/CGA fibers was slightly lower than that of neat PLA fiber. For PLA/CGA fibers, the 6-fold drawn PLA/CGA fiber with 3 % CGA owned the highest tensile strength of 420 MPa. The ultraviolet (UV) resistance of PLA/CGA fibers were enhanced significantly by the introduction of CGA. When the CGA content was not <3 %, the UV transmittance of PLA/CGA fibers was <8 %. Moreover, PLA/CGA fibers exhibited good antioxidant properties. PLA/CGA fibers with 10 % CGA owned the highest antioxidant rate of >90 %. In addition, the 6-fold drawn PLA/CGA fiber with 10 % CGA presented excellent release performance with a 7-day cumulative CGA release rate of 19 %.

Melt-spun polylactide/ethylene vinyl alcohol copolymer fiber.

Polylactide/ethylene vinyl alcohol copolymer (PLA/EVOH) blends and fibers with different weight ratios were prepared by melt blending, and two-step melt spinning, respectively. PLA and EVOH in PLA/EVOH blends were immiscible. When EVOH content was ≤60 %, EVOH with the average diameter of about 3 µm was dispersed in PLA matrix uniformly. The dual continuous phases could be observed in PLA/EVOH blend with 70 wt% EVOH. When the EVOH content was ≥80 %, the spherical PLA phase with the diameter of 0.25 to 1 µm was dispersed in EVOH matrix. The introduction of EVOH as nucleating agent could promote the crystallization of PLA. Both PLA and EVOH components in PLA/EVOH blends formed individual crystal phases. The viscosity of PLA/EVOH blend with 5 % EVOH was lower than that of neat PLA. The viscosity of PLA/EVOH blends with the EVOH content of ≥10 % was much higher than that of neat PLA, which showed obvious shear thinning behavior. With the increase of EVOH content, the shear thinning behavior became obvious and the critical shear rate decreased gradually. The drawn PLA/EVOH fibers with the tensile strength of ≥16 cN/tex exhibited good mechanical properties. In addition, the introduction of EVOH could improve the hydrophilicity of PLA fibers.

Structure and properties of polylactic acid/butenediol vinyl alcohol copolymer blend fibers.

Polylactic acid/butenediol vinyl alcohol copolymer (PLA/BVOH) blends with different weight ratios were prepared by melt mixing. PLA and BVOH in PLA/BVOH blends were immiscible while the weak interaction between PLA and BVOH existed. The introduction of BVOH facilitated the crystallization of PLA. Moreover, the crystallization of PLA hindered the crystallization of BVOH. Due to introduction of BVOH, PLA/BVOH blends exhibited shear thinning characteristic except that PLA/BVOH blends with 5-10 % BVOH showed similar rheological property to neat PLA. With the increase of BVOH content, the contact angle of PLA/BVOH blends decreased from 79.75° to 67.33° at 120 s. The hydrophilicity of PLA/BVOH blends was improved. In addition, PLA/BVOH fibers with 5-40 % BVOH and PLA/BVOH/rutin fibers with 3 % rutin were manufactured by melt spinning. The effect of BVOH on the mechanical property of PLA/BVOH fibers was small. However, BVOH improved significantly the rutin release rate and antioxidant properties of PLA/BVOH/rutin fibers.

Synthesis of biomass hyperbranched polyamide resin from cellulose and citric acid for wood adhesive.

Traditional wood adhesives have the problems of excessive dependence on fossil resources and environmental pollution. Cellulose, a renewable biomass resource with a low price and huge output, provides a basis for preparing biomass wood adhesives. In this study, a new type of polyamide resin was prepared by modifying microcrystalline cellulose and reacting with natural citric acid. Specifically, toluenesulfonyl cellulose (TS) was synthesized, and functional amino cellulose (AC) was prepared by a nucleophilic substitution reaction with hyperbranched polyamide (HP). Then cellulose-based hyperbranched polyamide resin (CHP) was prepared by polycondensation with citric acid. The structure of CHP resin was investigated by FTIR, XPS, 13C NMR and GPC, and plywood was prepared to study its mechanical properties. Due to the formation of hyperbranched cross-linked network structure inside the resin, the prepared plywood has excellent properties. The dry shear strength reaches 2.24 MPa, and the strength reaches 1.25 and 1.31 MPa after soaking in water at 63 °C and 93 °C for 3 h. The resin in this study has a simple preparation process and excellent performance, which provides a solid foundation for developing high-performance cellulose-based wood adhesives.

Smart photochromic materials based on polylactic acid.

The smart photochromic materials based on polylactic acid (PLA) were prepared by melt-blending and hot-pressing, in which photochromic microcapsules (PM) were used as a functional additive, and poly(vinyl acetate) (PVAc) was introduced into the photochromic PLA blends for the first time to improve their properties. The crystallization and melting behavior, morphology, and photochromic performance of PLA/PVAc/PM blends were characterized by differential scanning calorimetry (DSC), scanning electron microscopy (SEM), and spectrophotometer, respectively. The results showed that PVAc significantly improved the photochromic properties of PLA/PM blends. Under 30 s UV irradiation, the blends reached a value of ΔE that could be recognized in 3 s by human eyes. This discriminative ΔE value could be maintained for at least 3 min after removal from UV irradiation. Meanwhile, the blend had outstanding photochromic durability and recyclability. Compared to ΔE for 0.5 h of continuous light irradiation, ΔE for 8 h of continuous light irradiation decreased by only about 1, to 14.1. In 25 cycles of 3 s UV irradiation, the values of ΔE for the first and 25th irradiation were 11.4 and 11.6, respectively. The blend showed different photochromic responses to different light intensities. The ΔE values of 8.6, 14.6, 14.6, and 18.4 for irradiation at 600, 800, 1000, and 1200 W/m2 of solar intensity, respectively.