Chitin and chitosan in selected biomedical applications

Chitin (CT), the well-known natural biopolymer and chitosan (CS) (bio-based or “artificial polymer”) are non-toxic, biodegradable and biocompatible in nature. The advantages of these biomaterials are such that, they can be easily processed into different forms such as membranes, sponges, gels, scaffolds, microparticles, nanoparticles and nanofibers for a variety of biomedical applications such as drug delivery, gene therapy, tissue engineering and wound healing. Present review focuses on the diverse applications of CT and CS membranes and scaffolds for drug delivery, tissue engineering and targeted regenerative medicine. The chitinous scaffolds of marine sponges’ origin are discussed here for the first time. These CT based scaffolds obtained from Porifera possess remarkable and unique properties such as hydration, interconnected channels and diverse structural architecture. This review will provide a brief overview of CT and CS membranes and scaffolds toward different kinds of delivery applications such as anticancer drug delivery, osteogenic drug delivery, and growth factor delivery, because of their inimitable release behavior, degradation profile, mucoadhesive nature, etc. The review also provides an overview of the key features of CT and CS membranes and scaffolds such as their biodegradability, cytocompatibility and mechanical properties toward applications in tissue engineering and wound healing.     

Controlled accommodation of metal nanostructures within the matrices of polymer architectures through solution-based synthetic strategies

Controlled accommodation of metal nanostructures (MNSs) into the matrix of a well-defined polymer architecture offers an effective approach to achieve hierarchically structured nanocomposites with tunable synergistic properties to broaden application potentials in the emerging fields of energy, environmental science, and medicine. This review focuses on the recently developed zero-dimensional and one-dimensional MNSs@polymer hybrid nanostructures obtained by solution-based synthetic strategies. Progress in the controlled synthesis of those hybrid nanostructures in terms of the number (e.g., monomer, dimer and trimer), organization manner (e.g., linear alignment or confined assembly in certain domains), and spatial arrangement (e.g., in the core and shell) of the MNSs within the distinct polymer matrices are detailed. The synergistic properties and potential applications of those MNSs@polymer hybrids associated with their compositions and morphologies are also reviewed.     

纯化凹凸棒黏土与聚丙烯酸钠高吸水复合树脂的制备

采用反相悬浮聚合法制备了纯化凹士/聚丙烯酸钠高吸水复合树脂,使用傅立叶红外光谱仪研究了纯化凹土与丙烯酸的聚合情况,讨论了各种因素对复合材料吸蒸馏水、自来水和0.9%的盐水性能的影响.添加纯化凹土的吸水性能优于添加普通凹土的吸水性能.     

用于高强度聚焦超声热消融的PAA模块:模块的制作及声学参数的测量

目的研制一种透明的用于高强度聚焦超声热消融的PAA模块,并对其声学参数进行测量。方法观察模块浓度的不同所致颜色与透明度的变化,并对PAA模块的声学特性包括密度、声速及声衰减进行测量。结果(1)PAA模块为透明的琥珀色,蛋白浓度越高,颜色越深,透明度越低。(2)PAA模块的密度与水相近,为1.0250g/cm3至1.0617g/cm3。声速与模块浓度之间有明显的相关性。声衰减从0.125dB/cm至0.329dB/cm,随着模块密度与探头频率的增加而增加。结论PAA模块是一种较好的用于高强度聚焦超声热消融的均质仿体,实验结果有较好的重复性。     

PAA—PSF交联复合膜对有机物水溶液反渗透分离性能的研究

本文研究了ＰＡＡ－ＰＳＦ交联复合膜对有机醇，酸，胺，醛，酮，脂等水溶液的反渗透分离性能。结果表明，ＰＡＡ－ＰＳＦ交承复合膜对有机醇，胺和醛类水溶液有很很好的反渗透分离性能，对乙醇，乙胺和乙醛水溶液的截留率分别为６６．２％，５１％和８４％，且随分子量的增大，截留率不断上升。     

Characteristics of two types of stabilized nano zero-valent iron and transport in porous media

Nano-scale zero-valent iron (NZVI) has been shown to be suitable for remediating contaminated aquifers. However, they usually aggregate rapidly and result in a very limited migration distance that inhibits their usefulness. This study employed poly acrylic acid (PAA) and carboxymethyl cellulose (CMC) to synthesize two types of stabilized styles of NZVI with finer sizes (namely PNZVI and CNZVI). The mobility of stabilized NZVI was also demonstrated on the basis of transport in porous media. The results show that the PNZVI has a uniform particle size of 12 nm. However, tens of CNZVI particles with diameters of 1-3 nm were packed into secondary particles. Both the PNZVI and the CNZVI exhibited amorphous structures, and the stabilizer was bound to particle surfaces in the form of bidentate bridging via the carboxylic group, which could provide both electrostatic and steric repulsion to prevent particle aggregation. This study also proposes presumed stabilized configurations of PNZVI and CNZVI to reasonably illustrate their different dispersed suspension types. On the basis of the breakthrough curves and mass recovery, this study observed that the mobility of PNZVI in classic Ca²⁺ concentration of groundwater was superior to CNZVI. Nonetheless, the mobility of CNZVI would be decreased less significantly than PNZVI when encountering high Ca²⁺ concentrations (40 mM). Presumably, increasing the pore flow velocity would enhance the mobility of stabilized NZVI. Overall, the results of this study indicate that PNZVI has the potential to become an effective reactive material for in situ groundwater remediation.     

PAA、PLiAA和PNaAA涂膜结晶度对其表面性能的影响

采用辊涂的方式将聚丙烯酸（PAA）、聚丙烯酸锂（PLiAA）和聚丙烯酸钠（PNaAA）溶液涂覆在铝箔上，通过控制不同的烘干时间和温度以获得不同结晶度的涂膜。用x-射线衍射测定聚丙烯酸、聚丙烯酸锂和聚丙烯酸钠涂膜的表面结晶度，实验测定了涂膜的表面张力和水在涂膜表面的铺展速度常数。讨论了表面结晶度、表面张力、水铺展速度常数与涂膜表面亲水性之间的关系，结果表明具有高表面张力和结晶度的涂膜有利于亲水性的提高。     

PAA与Fenton试剂对污泥的减容效果

解决污泥问题的最好办法就是污泥减量.研究了两种强氧化剂过氧乙酸(PAA)和Fenton试剂对污泥的溶解特性.研究表明PAA与Fenton试剂对污泥都有一定的减容效果,相比而言,Fenton试剂对污泥的减容效果更为显著.PAA溶解污泥的极值时间为2 h,Fenton试剂溶解污泥的极值时间为0.5 h.在加入1 mol/L的NaOH,至污泥液pH=10的前提下,PAA和Fenton试剂对SS(suspend solid)的减少率分别高达65.4%,87.8%.     

Thermal Tb emission quenching in YAlO3 matrix embedded in porous anodic alumina

Terbium doped YAlO₃ composites were fabricated by the co-precipitation method in a porous anodic alumina (PAA) films grown on silicon at three different Tb concentrations: 0.23, 0.87 and 2.11 at.%. To investigate the emission thermal quenching for all samples, we measured the emission spectra as a function of temperature in the range from 10 up to 500 K at 266 and 488 nm excitation wavelengths. Based on obtained results we proposed the physical model explaining the mechanism of Tb³⁺ emission quenching in YAlO₃ composites deposited into PAA film.     

Benzoboroxole‐Functionalized Magnetic Core/Shell Microspheres for Highly Specific Enrichment of Glycoproteins under Physiological Conditions

Efficient enrichment of specific glycoproteins from complex biological samples is of great importance towards the discovery of disease biomarkers in biological systems. Recently, phenylboronic acid‐based functional materials have been widely used for enrichment of glycoproteins. However, such enrichment was mainly carried out under alkaline conditions, which is different to the status of glycoproteins in neutral physiological conditions and may cause some unpredictable degradation. In this study, on‐demand neutral enrichment of glycoproteins from crude biological samples is accomplished by utilizing the reversible interaction between the cis‐diols of glycoproteins and benzoboroxole‐functionalized magnetic composite microspheres (Fe₃O₄/PAA‐AOPB). The Fe₃O₄/PAA‐AOPB composite microspheres are deliberately designed and constructed with a high‐magnetic‐response magnetic supraparticle (MSP) core and a crosslinked poly(acrylic acid) (PAA) shell anchoring abundant benzoboroxole functional groups on the surface. These nanocomposites possessed many merits, such as large enrichment capacity (93.9 mg/g, protein/beads), low non‐specific adsorption, quick enrichment process (10 min) and magnetic separation speed (20 s), and high recovery efficiency. Furthermore, the as‐prepared Fe₃O₄/PAA‐AOPB microspheres display high selectivity to glycoproteins even in the E. coli lysate or fetal bovine serum, showing great potential in the identify of low‐abundance glycoproteins as biomarkers in real complex biological systems for clinical diagnoses.