Surface modification of UHMWPE/fabric composite membrane via self-polymerized polydopamine followed by mPEG-NH2 immobilization

Current State-of-the-Art in Membrane Formation from Ultra-High Molecular Weight Polyethylene

One of the materials that attracts attention as a potential material for membrane formation is ultrahigh molecular weight polyethylene (UHMWPE). One potential material for membrane formation is ultrahigh molecular weight polyethylene (UHMWPE). The present review summarizes the results of studies carried out over the last 30 years in the field of preparation, modification and structure and property control of membranes made from ultrahigh molecular weight polyethylene. The review also presents a classification of the methods of membrane formation from this polymer and analyzes the conventional (based on the analysis of incomplete phase diagrams) and alternative (based on the analysis of phase diagrams supplemented by a boundary line reflecting the polymer swelling degree dependence on temperature) physicochemical concepts of the thermally induced phase separation (TIPS) method used to prepare UHMWPE membranes. It also considers the main ways to control the structure and properties of UHMWPE membranes obtained by TIPS and the original variations of this method. This review discusses the current challenges in UHMWPE membrane formation, such as the preparation of a homogeneous solution and membrane shrinkage. Finally, the article speculates about the modification and application of UHMWPE membranes and further development prospects. Thus, this paper summarizes the achievements in all aspects of UHMWPE membrane studies.

Functional Ultra-High Molecular Weight Polyethylene Composites for Ligament Reconstructions and Their Targeted Applications in the Restoration of the Anterior Cruciate Ligament

The selection of biomaterials as biomedical implants is a significant challenge. Ultra-high molecular weight polyethylene (UHMWPE) and composites of such kind have been extensively used in medical implants, notably in the bearings of the hip, knee, and other joint prostheses, owing to its biocompatibility and high wear resistance. For the Anterior Cruciate Ligament (ACL) graft, synthetic UHMWPE is an ideal candidate due to its biocompatibility and extremely high tensile strength. However, significant problems are observed in UHMWPE based implants, such as wear debris and oxidative degradation. To resolve the issue of wear and to enhance the life of UHMWPE as an implant, in recent years, this field has witnessed numerous innovative methodologies such as biofunctionalization or high temperature melting of UHMWPE to enhance its toughness and strength. The surface functionalization/modification/treatment of UHMWPE is very challenging as it requires optimizing many variables, such as surface tension and wettability, active functional groups on the surface, irradiation, and protein immobilization to successfully improve the mechanical properties of UHMWPE and reduce or eliminate the wear or osteolysis of the UHMWPE implant. Despite these difficulties, several surface roughening, functionalization, and irradiation processing technologies have been developed and applied in the recent past. The basic research and direct industrial applications of such material improvement technology are very significant, as evidenced by the significant number of published papers and patents. However, the available literature on research methodology and techniques related to material property enhancement and protection from wear of UHMWPE is disseminated, and there is a lack of a comprehensive source for the research community to access information on the subject matter. Here we provide an overview of recent developments and core challenges in the surface modification/functionalization/irradiation of UHMWPE and apply these findings to the case study of UHMWPE for ACL repair.

Development and assessment of biologically compatible anterior cruciate ligament using braided ultra-high molecular weight polyethylene

In this study, a ultra-high molecular weight polyethylene (UHMWPE) braided structure was surface modified with low temperature plasma and was coated with cationized gelatin and hyaluronic acid to improve its biocompatibility for the reconstruction of an anterior cruciate ligament (ACL). The ligament was studied for its various mechanical properties. Surface modifications were studied through FESEM. Biological compatibility of the ligament was assessed in accordance to ISO 10993 standard. Tensile strength of the UHMWPE reconstructed ligament ranges between 2628 and 5937 N; maximum tensile strength was attained in 1600 denier 2/2 pattern of triple braided structure along with higher strain at failure of 36.1%. In 1600 denier 2/2 pattern of triple braid structure, the linear stiffness was found to be high at 375 N/mm. Among the developed materials, four braided structures namely as 800 denier 2/2 pattern of double braids and triple braids, 1600 denier 1/1 pattern of double braid and 2/2 pattern of triple braid were found to be mechanically suitable. Specifically, the 1600 denier 2/2 pattern of triple braid having higher mechanical properties was selected for coating. The results of in-vitro cytotoxicity and genotoxicity confirmed the extract of ACL to non-toxic and non-mutant. Furthermore, in-vivo analysis of the extract and the coated ACL graft proved the ligament to be non-irritant, non-sensitizer and also found to promote new tissue formation around the graft. Based on the results, the CG and HA coated ACL graft were concluded to be biocompatible and having considerable potential as an alternate for autograft/allograft.

Multifunctional Polydopamine Particles as a Thermal Stability Modifier to Prepare Antifouling Melt Blend Composite Membranes

This study reports a novel, multifunctional, and easily obtained modifier to support the rapid advancements in the field of filtration. Polydopamine (PDA) particles (PDAPs) have been reported as a filler for constructing polymer composites, but because of their poor thermal stability, the use of PDAPs in high-temperature blend melt systems to construct antifouling membranes was rare. In this paper, high-thermal-stability methoxy polyethylene glycol amine (mPEG-NH₂)-functionalized PDA nanoparticles (mPDAPs) were first used as a modifier in high-temperature blend melt polymer composites to construct antifouling composite membranes. First, high-thermal-stability mPDAPs with an average diameter of about 390 nm were prepared by immobilized mPEG-NH₂ on the PDAP surface, then melt blend mPDAPs with ultrahigh-molecular-weight polyethylene/liquid paraffin (LP) solution and thermally reduced phase separation (TIPS) to construct antifouling membranes. A combination of properties including mechanical properties, filtration efficiency, and antifouling properties of hybrid composite membranes was investigated and demonstrated that mPDAPs were an efficient modifier for high-temperature melt blending systems. The aim of this study was to provide an effective approach to improve the membrane filtration performance by bulk hybrid modification of multifunctional nanoparticles.