Bioactivity modification helps Polymethylmethacrylate (PMMA) bone cement to reinforce its interfacial adhesion to bone tissues through the chemical bonding of apatite. Since Si-OH groups combined with Ca2+ ions have succeeded in inducing apatite formation, more combinations of functional groups and active ions are being explored. In this study, Bis[2-(methacryloyloxy)ethyl] phosphate (B2meP) containing phosphate (=PO4H) groups and Ca(CH3COO)2 supplying Ca2+ ion were adopted to investigate the feasibility of equipping PMMA bone cement with apatite-forming ability in vitro, more effects under designed contents on setting behavior, injectability, contact angle, cytotoxicity and mechanical strength were also investigated. Results showed B2meP copolymerized with MMA and became one section of PMMA chains, surface = PO4H groups and released Ca2+ ions pushed spherical apatite individuals nucleating and agglomerating into layer horizontally, Increasing B2meP content lowered the contact angle and the peak temperature, enhanced the cell viability of MC3T3-E1, but prolonged apatite forming period. Injectability rates performed a similar trend to setting time. Lower adding content and deposited apatite layer contributed to reduce the strength loss in soaking. Taking biological performance and other properties into balance, cement added with B2meP of 10 wt% in MMA and Ca(CH3COO)2 of 20 wt% in PMMA performed better.
A novel IPN hydrogel scaffold is prepared by freeze-drying method, in which konjac galactomannan (KGM) and gelatin are physically crosslinked respectively. This scaffold is thermostable, and the structure of this scaffold is analysed by scanning electron microscope, Fourier transform infrared spectrum, and X-ray diffraction method. The FT-IR results show that hydrogen bonds are formed between KGM and gelatin molecules, which hinder the formation of their respective crosslinking. This is consistent with the XRD results that the crystallinity gets lower in the IPN gels compared with pure gelatin and KGM gels. The morphologies of freezedried hydrogels are observed by SEM and the mechanical properties of the scaffolds are tested to analyse the relationship between the structures and properties. Although this novel IPN hydrogel is physical gel, it shows rubber-like performance as chemical gels. And it is nontoxic, so it can be used as the scaffold for cartilage tissue engineering that embedded in human bodies.
Due to higher molecular density, lower ionization potential, and a better self-healing property compared with gases, liquid targets have been used for laser-induced terahertz generation for many years. In this work, a liquid target used for terahertz radiation is embedded with silver nanoparticles (Ag NPs), which makes the material have both the fluidity of liquids and conductivity of metals. Meanwhile, the experimental setup is easier to implement than that of liquid metals. Polyvinyl alcohol (PVA) is used as a stabilizing agent to avoid precipitation formation. It is observed that the power of 0.5 THz radiation from the Ag NP suspension is five times stronger than that from liquid water in identical experimental conditions. In addition, the reusability of the material is investigated using multiple excitations. UV–visible spectroscopy and TEM imaging are carried out to analyze the target material after each excitation. As a result, quasispherical Ag NP suspensions show good reusability for several excitations and only a decrease in particle concentration is observed. By contrast, the chain-like Ag NP suspension shows poor stability due to PVA damage caused by intense laser pulses, so it cannot be used in a recyclable manner.
17 April 2024 in Journal of Materials Research and Technology