Deposition of Biocompatible Polymers by 3D Printing (FDM) on Titanium Alloy

Nowadays, the replacement of a hip joint is a standard surgical procedure. However, researchers have continuingly been trying to upgrade endoprostheses and make them more similar to natural joints. The use of 3D printing could be helpful in such cases, since 3D-printed elements could mimic the natural lubrication mechanism of the meniscus. In this paper, we propose a method to deposit plastics directly on titanium alloy using 3D printing (FDM). This procedure allows one to obtain endoprostheses that are more similar to natural joints, easier to manufacture and have fewer components. During the research, biocompatible polymers suitable for 3D FDM printing were used, namely polylactide (PLA) and polyamide (PA). The research included tensile and shear tests of metal–polymer bonds, friction coefficient measurements and microscopic observations. The friction coefficient measurements revealed that only PA was promising for endoprostheses (the friction coefficient for PLA was too high). The strength tests and microscopic observations showed that PLA and PA deposition by 3D FDM printing directly on Ti6Al4V titanium alloy is possible; however, the achieved bonding strength and repeatability of the process were unsatisfactory. Nevertheless, the benefits arising from application of this method mean that it is worthwhile to continue working on this issue.

Systematic Investigation of Biocompatible Cationic Polymeric Nucleic Acid Carriers for Immunotherapy of Hepatocellular Carcinoma

Hepatocellular carcinoma (HCC) is the third-largest cause of cancer death worldwide, while immunotherapy is rapidly being developed to fight HCC with great potential. Nucleic acid drugs are the most important modulators in HCC immunotherapy. To boost the efficacy of therapeutics and amplify the efficiency of genetic materials, biocompatible polymers are commonly used. However, under the strong need of a summary for current developments of biocompatible polymeric nucleic acid carriers for immunotherapy of HCC, there is rare review article specific to this topic to our best knowledge. In this article, we will discuss the current progress of immunotherapy for HCC, biocompatible cationic polymers (BCPs) as nucleic acid carriers used (or potential) to fight HCC, the roles of biocompatible polymeric carriers for nucleic acid delivery, and nucleic acid delivery by biocompatible polymers for immunotherapy. At the end, we will conclude the review and discuss future perspectives. This article discusses biocompatible polymeric nucleic acid carriers for immunotherapy of HCC from multidiscipline perspectives and provides a new insight in this domain. We believe this review will be interesting to polymer chemists, pharmacists, clinic doctors, and PhD students in related disciplines.

Al2O3 Preforms Infiltrated with Poly(methyl methacrylate) for Dental Prosthesis Manufacturing

The combination of biocompatible polymers and ceramics shows great promise in the development of composites with suitable mechanical properties for dental applications. In an attempt to further expand this research line, Al2O3 commercial powders (Vitro-ceram, Alglass, In-ceram) were sintered at 1400 °C for 2 h and infiltrated with poly(methyl methacrylate) for potential use in dental prostheses. The infiltration was performed using a homemade apparatus under a pressure of 7 bar for 6 and 12 h. The microstructure (studied using a scanning electron microscope), Archimedes density, 3-point bending flexural strength and Vickers hardness of the prepared composites were assessed and quantitatively compared. In general, microstructural analyses showed ceramic- and polymer-based interpenetrating network in all materials. The preforms infiltrated for 12 h showed superior properties; among them, the Vitro-ceram-based composite also demonstrated a near-zero open porosity and optimum mechanical characteristics. Specifically, its density, strength and hardness were 2.6 ± 0.07 g/cm3, 119.3 ± 5.0 MPa and 1055.1 ± 111.0 HV, respectively, passing the acceptance criteria of ISO 6872 and making it suitable for consideration as a metal-free structure for dental crowns and fixed partial prostheses until three anterior units.

Graphene based nanocomplexes can be rationally modified with a variety of functional compounds to improve therapeutic effectiveness including gene therapy

Graphene-family nanomaterials (GFNs)-based nanocomplexes have been hailed as a rising star in the field of nanomaterials. GFNs can be rationally modified with a variety of functional chemicals to improve therapeutic effectiveness. The active targeted drug delivery of GFNs is facilitated by conjugating with particular targeting ligands. A phototherapy method combining GFNs and PSs that may cause the formation of ROS with the help of NIR light irradiation, for example, has been shown to be effective in PTT. GFNs can cause cellular injuries such as cytoskeletal disorders, organelle dysfunction, protein corona damage, and damage to biological macromolecules after being absorbed into the human body. To decrease the toxicity of GFNs, biocompatible polymers such as peptides, PEG, hyperbranched polyglycerol, -cyclodextrin, and a variety of polysaccharides have been used. When combined with successful treatment methods, GFNs have the potential to be used in a range of clinical applications in biomedicine, including biosensing, bioimaging, tissue engineering, and medication delivery. However, success in translating GFNs-based nanocomplexes from the bench to the bedside remains a long way off.

Nanocomposites based on biocompatible polymers and graphene oxide for antibacterial coatings

Recently, antibacterial coatings based on graphene oxide (GO) nanocomposites have attracted many studies around the world. The use of polymers as the matrices of GO nanofillers in the nanocomposites has been explored to produce efficient coatings against bacteria. One of the most prospective applications is the incorporation of GO into biocompatible polymers, which can produce antibacterial coatings. Here, recent progresses on the antibacterial coatings of nanocomposites based on biocompatible polymers and GO are reviewed. The effect of GO filler concentrations, biocide materials, and biocompatibility are discussed to find the most efficient antibacterial activity and biocompatibility of nanocomposites. Among biocompatible polymers, chitosan (Cs), poly vinyl alcohol (PVA), and poly lactic acid (PLA) are the most popular matrices used for the nanocomposites. This review also elaborates challenges in the use of other biocompatible polymers. Future works on biocompatible antibacterial coatings should be conducted by considering the concentration of GO nanofillers or adding other materials such as essential oils to suppress the toxicity toward functional cells.

Chain End Effect for Intermediate Water Formation of Poly(2-methoxyethyl acrylate)

Intermediate water (IW), which is formed not only biocompatible polymers represented by poly(2-methoxyethyl acrylate) (PMEA) but also biomacromolecules, has a key role to display biocompatibility of synthetic polymers. In this paper, we demonstrated comparative experiments between the well-defined linear and cyclic PMEA using differential scanning calorimetry (DSC) and atomic force microscope (AFM) techniques to clarify chain end effect for IW formation toward establishment of guideline of biomaterials.