Rapid Fabrication of Patterned Gels via Microchannel-Conformal Frontal Polymerization.

From the perspective of both fundamental and applied science, it is extremely advisable to develop a facile and feasible strategy for fabricating gels with defined structures. Herein, the authors report the rapid synthesis of patterned gels by conducting frontal polymerization (FP) at millimeter-scale (2 mm), where a series of microchannels, including linear-, parallel-, divergent-, snakelike-, circular- and concentric circular channels, were used. They have investigated the effect of various factors (monomer mass ratio, channel size, initiator concentration, and solvent content) on FP at millimeter-scale, along with the propagating rule of the front during FP in these microchannels. In addition, we developed a new microfluidic-assisted FP (MFP) strategy by combining the FP and microfluidic technique. Interestingly, the MFP can realize the production of hollow-structured gel in a rapid and continuous fashion, which have never been reported. Our work not only offers an effective pathway towards patterned gels by the microchannel-conformal FP, but also gives new insight into the continuous production of hollow-structured materials. Such a method will be beneficial for fabricating vessel and scaffold materials in a flexible, easy-to-perform, time and energy saving way.

Phosphorylation-regulated crosslinking of gold nanoparticles: a new strategy for colorimetric detection of protein kinase activity.

Accurate and rapid detection of protein kinase activities is of great significance because protein kinases play important regulatory roles in many vital biological processes. Herein, we wish to report a facile colorimetric protein kinase assay based on the phosphorylation-tuned crosslinking of gold nanoparticles (GNPs) by using protein kinase A (PKA) as a proof-of-concept target. In this new strategy, a biotinylated peptide (biotin-LRRASLG) is used as the PKA-specific substrate. When mixed with streptavidin-functionalized GNPs (STV-GNPs), the positively charged biotin-peptide will combine with different GNPs both through the specific STV-biotin binding and through electrostatic interactions, which will lead to the crosslinking and coagulation of GNPs. In contrast, under the catalysis of PKA, the biotin-peptide will be phosphorylated at the serine residue and its net charge will be obviously altered, which may significantly weaken the electrostatic interaction between the phosphopeptide and GNPs and thus effectively prevent the STV-GNPs from crosslinking and settlement. Therefore, by viewing the color changes of the GNPs, the PKA activity can be easily detected by the naked eye.

Rapid Preparation of Superabsorbent Self-Healing Hydrogels by Frontal Polymerization.

Hydrogels have received increasing interest owing to their excellent physicochemical properties and wide applications. In this paper, we report the rapid fabrication of new hydrogels possessing a super water swelling capacity and self-healing ability using a fast, energy-efficient, and convenient method of frontal polymerization (FP). Self-sustained copolymerization of acrylamide (AM), 3-[Dimethyl-[2-(2-methylprop-2-enoyloxy)ethyl]azaniumyl]propane-1-sulfonate (SBMA), and acrylic acid (AA) within 10 min via FP yielded highly transparent and stretchable poly(AM-co-SBMA-co-AA) hydrogels. Thermogravimetric analysis and Fourier transform infrared spectroscopy confirmed the successful fabrication of poly(AM-co-SBMA-co-AA) hydrogels with a single copolymer composition without branched polymers. The effect of monomer ratio on FP features as well as porous morphology, swelling behavior, and self-healing performance of the hydrogels were systematically investigated, showing that the properties of the hydrogels could be tuned by adjusting the chemical composition. The resulting hydrogels were superabsorbent and sensitive to pH, exhibiting a high swelling ratio of up to 11,802% in water and 13,588% in an alkaline environment. The rheological data revealed a stable gel network. These hydrogels also had a favorable self-healing ability with a healing efficiency of up to 95%. This work contributes a simple and efficient method for the rapid preparation of superabsorbent and self-healing hydrogels.

Rapid Synthesis of Robust Antibacterial and Biodegradable Hydrogels via Frontal Polymerization.

Chitosan (CS) is widely used in biomedical hydrogels due to their similarity to extracellular matrix. However, the preparation method of CS-based hydrogel suffers the drawbacks of tedious operation, time-consuming and energy consumption. Thus, there is an urgent need to develop a rapid synthesis pathway towards hydrogels. In this work, we used a modified CS as a cross-linking agent and acrylic acid (AA) as monomer to prepare a hydrogel through frontal polymerization (FP), which facilitates a facile and rapid method achieved in several minutes. The occurrence of pure FP was confirmed via the frontal velocity and temperature profile measurement. In addition, the as-prepared hydrogel shows excellent mechanical strength up to 1.76 MPa, and the Young's modulus (ranging from 0.16 to 0.56 MPa) is comparable to human skin. The degradation mechanism is revealed by the micro-IR images through the distribution of the functional groups, which is attributed to the breakage of the ether bond. Moreover, the hydrogel exhibits excellent degradability, biocompatibility and antibacterial properties, offering great potentials in tissue engineering. We believe this work not only offers a facile and rapid FP method to fabricate a robust degradable hydrogel, but also provides an effective pathway for the investigation of the degradation mechanism at the chemical bond analysis level.

Quantum Dots-Loaded Self-Healing Gels for Versatile Fluorescent Assembly.

From the perspective of applied science, methods that allow the simple construction of versatile quantum dots (QDs)-loaded gels are highly desirable. In this work, we report the self-healing assembly methods for various fluorescent QDs-loaded gels. Firstly, we employed horizontal frontal polymerization (FP) to fabricate self-healing gels within several minutes using a rapid and energy-saving means of preparation. The as-prepared gels showed pH sensitivity, satisfactory mechanical properties and excellent self-healing properties and the healing efficiency reached 90%. The integration of the QDs with the gels allowed the generation of fluorescent composites, which were successfully applied to an LED device. In addition, by using the self-healing QDs-loaded gels as building blocks, the self-healing assembly method was used to construct complex structures with different fluorescence, which could then be used for sensing and encoding. This work offers a new perspective on constructing various fluorescent assemblies by self-healing assembly, and it might stimulate the future application of self-healing gels in a self-healing assembly fashion.

MOF-Based Photonic Crystal Film toward Separation of Organic Dyes.

Metal-organic framework (MOF)-directed photonic structure materials have inspired great attention for extended and enhanced functions. However, the direct construction of photonic crystals (PCs) with MOF particles as building blocks still remains a challenge. Herein, we designed and synthesized monodisperse polyamidoamine (PAMAM) dendrimer-modified zeolitic imidazolate framework (ZIF-8) particles (PAMAM@ZIF-8) via a postsynthetic method, rendering ZIF-8 with hydrophilicity. It was found that the PAMAM@ZIF-8 particles could directly assemble into a uniform photonic structure and effectively suppressed the coffee-ring effect, forming homogeneous PC films with different structural colors. A PC pattern with angle-dependent colors was also achieved, which might have potential applications in the field of anticounterfeiting printing. More importantly, by taking advantages of a membrane separation-assisted assembly process, a colorful and robust PC film was accomplished on the surface of reduced graphene oxide (rGO). The hierarchal PAMAM@ZIF-8/rGO film demonstrates a superior separation ability toward organic dye solutions, which enriches the function of PC materials. This work gives a new insight into the fabrication of MOF-based functional PC materials, which will extend the application of PCs in the high selective and effective separation field.

Value of the albumin-bilirubin score in the evaluation of hepatitis B virus-related acute-on-chronic liver failure, liver cirrhosis, and hepatocellular carcinoma.

The aim of the present study was to investigate the value of the albumin-bilirubin (ALBI) score in the assessment of the disease conditions of hepatitis B virus (HBV)-related acute-on-chronic liver failure (HBV-ACLF), HBV-related liver cirrhosis (HBV-LC) and HBV-related hepatocellular carcinoma (HBV-HCC). A total of 395 patients with HBV-ACLF, HBV-LC, or HBV-HCC were retrospectively studied. The ALBI, Child-Turcotte-Pugh (CTP), and Model for End-Stage Liver Disease (MELD) scores of the patients were calculated, and the relationships between the ALBI score and the CTP and MELD scores were investigated. Furthermore, the ALBI grading was tested for the evaluation of the severity and stages of HBV-ACLF, HBV-LC, and HBV-HCC, especially when classifying the clinical stages of HBV-ACLF. The mean ALBI scores of the HBV-ACLF, HBV-LC, and HBV-HCC patients were -1.17±0.55, -1.76±0.66 and -2.59±0.62, respectively; the mean CTP scores were 10.70±1.81, 8.19±1.25 and 5.81±1.22, respectively; and the mean MELD scores were 19.93±7.44, 11.10±4.39 and 7.01±3.22, respectively. The ALBI scores were positively correlated with the CTP and MELD scores. The mean ALBI score and the frequency of grade 3 disease were higher in HBV-ACLF patients than in patients with HBV-LC or HBV-HCC. A later HBV-ACLF stage resulted in a higher frequency of ALBI grades of 3. In conclusion, ALBI scores exhibited parallel tendencies to the CTP and MELD scores in HBV-ACLF, HBV-LC, and HBV-HCC patients; thus, ALBI grading may be a simple but applicable method for the evaluation of the functional status of patients with HBV-related end-stage liver diseases.

Quantum-dot-embedded ionomer-derived films with ordered honeycomb structures via breath figures.

A new approach for fabricating a series of multi-functional honeycomb-patterned films was successfully achieved using ionomers via breath figures.