Fluorescence and Photosensitizing Behavior of N-(p-Phenoxyphenyl)methacrylamide and Its Polymer

A novel acrylic monomer bearing aromatic ethereality group N-(p -phenoxy-phenyl) methacrylamide(MAPOA) was synthesized and polymerized. The fluorescence spectra of MAPOA and its polymer were studied, showing that the polymer displays a stronger fluorescence than its monomer at the same chromophore concentration. The fluorescence of P(MAPOA) was quenched by adding electron deficiency monomers such as MMA, AN etc .. It is another example of showing the 'fluorescence structural self-quenching effect' as we reported previously, from which it is demonstrated again that this phenomenon is not an accidental one but a common effect for acrylic monomers bearing electon-donating chromophores. The photopolymerization of AN sensitized by MAPOA and P(MAPOA) was studied. The kinetic equation of the polymerization was obtained and represented as follows: R _p∝ 0.38 × 0.78 , R _p∝ 0.33 × 0.71 The overall activation energies were determined to be E_ a =24\^22 kJ/mol(MAPOA) and E_ a =26\^31 kJ/mol respectively. The fluorescence analysis of the resulted P(AN) showed that the sensitizer also entered into the P(AN) chains. A mechanism of the formation of a charge transfer complex and free radical initiation was suggested for the photopolymerization of AN sensitized by MAPOA and P(MAPOA).

Comb-like Poly(N-(2-hydroxypropyl) methacrylamide) Doxorubicin Conjugates: The Influence of Polymer Architecture and Composition on the Biological Properties

The synthesis and structure-property correlation of poly（N-（2-hydroxypropyl） methacrylamide） （PHPMA） conjugates with various architectures including random, block, branched or star-like structures and compositions have been thoroughly explored. However, related synthesis and structure-property data are still lacking for comb-like PHPMA. In this work, we report the synthesis of comb-like PHPMA copolymer-doxorubicin （DOX） conjugates with different backbone/side-chain lengths and location of drug moieties. Well-defined comb-like PHPMA-DOX conjugates are obtained via the combination of controlled radical polymerization and fractional precipitation techniques. The influences of structural factors on the biological properties such as cellular uptake, blood circulation and tumor accumulation have been investigated. Long blood circulation and efficient tumor accumulation can be achieved by proper control of the comb number, length and location of drug moieties. These facile comb-like structures possess great potentials in future theranostics for brachytherapy or surgical navigation.

Enhanced Adhesion of Mussel-inspired Adhesive through Manipulating Contents of Dopamine Methacrylamide and Molecular Weight of Polymer

The aim of this study is to investigate the effect of the contents of modified 3, 4-dihydroxyphenyl-L-alanine （DOPA）, named as do- pamine methacrylamide （DMA）, on the adhesion of mussel-inspired adhesives in air and water. A series of adhesives, p（DMA-co-MEA）, were synthesized by copolymerized DMA and methoxy ethylacrylate （MEA） with the content of DMA from 2 mol.% to 10 mol.%. Results of IH NMR show that the contents of DMA in all adhesives are near to the theory ratios of DMA in the staring reagents. Adhesives with more than 5 mol.% of DMA appear adhesion, while adhesives with 2 mol. % and 3 mol. % of DMA show almost no adhesion in air and water. Adhesive with 7 mol.% of DMA has the highest molecular weight and adhesion either in air or in water in all adhesives. Adhesion of adhesive is synergistically influenced by the content of DMA, molecular weight and elastic modulus of adhesive. It is because that higher content of DMA would provide more DOPA, which leads to the coordination bond between DOPA and metal ions. It is feasible to develop the mussel-inspired adhesive through incorporating DMA into polymers, which will have potential application in the clinic.

3D printing of personalized polylactic acid scaffold laden with GelMA/autologous auricle cartilage to promote ear reconstruction

At present,the clinical reconstruction of the auricle usually adopts the strategy of taking autologous costal cartilage.This method has great trauma to patients,poor plasticity and inaccurate shaping.Three-dimensional(3D)printing technology has made a great breakthrough in the clinical application of orthopedic implants.This study explored the combination of 3D printing and tissue engineering to precisely reconstruct the auricle.First,a polylactic acid(PLA)polymer scaffold with a precisely customized patient appearance was fabricated,and then auricle cartilage fragments were loaded into the 3D-printed porous PLA scaffold to promote auricle reconstruction.In vitro,gelatin methacrylamide(GelMA)hydrogels loaded with different sizes of rabbit ear cartilage fragments were studied to assess the regenerative activity of various autologous cartilage fragments.In vivo,rat ear cartilage fragments were placed in an accurately designed porous PLA polymer ear scaffold to promote auricle reconstruction.The results indicated that the chondrocytes in the cartilage fragments could maintain the morphological phenotype in vitro.After three months of implantation observation,it was conducive to promoting the subsequent regeneration of cartilage in vivo.The autologous cartilage fragments combined with 3D printing technology show promising potential in auricle reconstruction.