Hailin Lu

Laser-textured surface storing a carbon dots/poly(ethylene glycol)/chitosan gel with slow-release lubrication effect

Arthroplasty presents wear problems because body fluid, as the only lubricant, has poor performance. However, normal lubricants become diluted by body fluid and then are absorbed by the human body. To prolong the lubricants effectiveness, this study prepared a carbon dots/poly(ethylene glycol)/chitosan (CDs/PEG/CS) composite gel, which, stored in laser textures, could slowly release the lubricant. Laser-textured surfaces can simultaneously store CDs/PEG/CS gel and wear debris. In this study, CDs, PEG and chitosan (CS), which have biocompatibility and biodegradability properties, can be used in the human body. CDs/PEG/CS gel was added to the laser textures and had excellent slow-release properties, which became better under pressure. Meanwhile, carbon dots (CDs) associated with poly(ethylene glycol) (PEG) via hydrogen bond formed an excellent lubricant, which led to the good lubrication effect. This study provides a new and green approach to enhance the tribological performance of artificial joints.

Laser textured Co-Cr-Mo alloy stored chitosan/poly(ethylene glycol) composite applied on artificial joints lubrication

Arthroplasty brings the wear problems because of body fluid has poor performance as lubricant. Lubricant which is used in artificial joints will rapidly degrade and be absorbed by human body after injecting. To prolong the lubricants effectiveness, this study prepared chitosan/poly(ethylene glycol) (CS/PEG) and textures to play a role in joint lubrication and wear protection. Chitosan (CS) and poly(ethylene glycol) which have biocompatibility and biodegradability properties can be used in human body. The tribological results shown that CS/PEG sol has excellent performance when this sol was composed by 2wt% CS and 30wt% PEG, the average friction coefficient below 0.016 under the condition of 30-90N load (pressure 4.2-12.6MPa). In this study, CS/PEG was added in the texture of artificial joints, then the surfaces of the CS/PEG formed gel via NaOH solidification effect. The CS/PEG gel film could prevent the CS/PEG sol from diluting in body fluid. Meanwhile, FT-IR, XRD, UV/vis and Raman spectra revealed that CS associated with PEG via hydrogen bond effect may form a particular structure, which leaded the good tribological performance. This study provides a new, simple and green approach to enhance tribological performances of artificial joints.

Biotribological application of poly(ε-caprolactone)-poly(ethylene glycol)-poly(ε-caprolactone) hydrogel as an efficient carrier with slow-release lubrication effect

Excessive wear debris in prosthesis tends to induce loosening, which is a major problem affecting the durability of long-serving implants. Although bionic synovial fluid can be used to improve the lubrication of artificial joints, the fluid is often absorbed easily by the tissues of human body. To enhance the effectiveness of bionic synovial fluid, poly(ε-caprolactone)-poly(ethylene glycol)-poly(ε-caprolactone) (PCEC) hydrogel was prepared as a carrier for the bovine serum albumin (BSA) in synovial fluid. It thus significantly reduces the loss rate of BSA. Experimental results show that the good sustainability and favorable release ability of hydrogel efficiently prevent the rapid outflowing of BSA. Experiments also reveal that the PCEC hydrogel inclines to form a particular structure with BSA and thus give BSA an excellent slow-release performance. Furthermore, friction and wear tests indicate that the released solution from the PCEC hydrogel possesses good lubricating properties. In general, the average friction coefficient of released solution is approximatively 77% lower than that of the normal phosphate-buffered solution. This study furnishes with an effective approach to prolong the lubricating duration of BSA in artificial prostheses.

Poly(ethylene glycol)/chitosan/sodium glycerophosphate gel replaced the joint capsule with slow-release lubricant after joint surgery

Abstract Body fluid is normally the only lubricant after joint replacement surgery, but wear problems have occurred because body fluid has poor lubrication ability. However, traditional lubricant would be diluted by body fluids and then absorbed by the human body. Therefore, an injectable gel with the ability to slow-release lubricant was designed to replace the joint capsule. The proposed gel, poly(ethylene glycol)/chitosan/sodium glycerophosphate (PEG/CS/GP) composite gel was then tested. The tribology results showed that the PEG/CS/GP gel had excellent slow-release properties, especially under pressure, and the PEG played an important role in improving the gel’s rheological and mechanical properties. Moreover, this study revealed that the release solution had a good lubrication effect because the PEG and GP could crosslink via the hydrogen bond effect.

Carbon dots intensified poly (ethylene glycol)/chitosan/sodium glycerophosphate hydrogel as artificial synovium tissue with slow-release lubricant

The ultra-high molecular weight polyethylene (UHMWPE) and metal artificial joint pair is limited by wear debris and short service life. Here we report the development of a hydrogel which exhibits lubricant release to intensify the lubrication effect of artificial joints.This study adopted an injectable method to prepare carbon dots/poly (ethylene glycol)/chitosan/sodium glycerophosphate (CDs/PEG/CS/GP) composite hydrogel, and the carbon dots were used to intensify the rheological and mechanical properties. In addition, the composite hydrogel had slow-release properties, and the release solution contained CDs, PEG and GP has excellent lubrication effect. At last, the MTT assay, LIVE/DEAD staining, H&E staining results and safety evaluation in BALC/c mice proved that the hydrogels had good biocompatibilility and were safety for application in vivo.

One-pot synthesis and lubricity of fluorescent carbon dots applied on PCL-PEG-PCL hydrogel

Abstract This work presents a method for one-pot synthesis of N-doped nanometer-size carbon dots, which can be assembled with thermosensitive poly(ε-caprolactone)-poly(ethylene glycol)-poly(ε-caprolactone) (PCL-PEG-PCL, PCEC) hydrogel to achieve slow-release lubricity. The typical property of this green production was studied by fourier transform infrared (FT-IR), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS) and transmission electron microscope (TEM). The photoluminescence of composite PCEC/CDs hydrogel and its released solutions were characterized by ultraviolet spectrum, and the rheological properties were tested by rotary rheometer. Tribological performance of the released solution from composite PCEC/CDs hydrogel was obtained to compare with PBS and pure CDs solution. The experimental results reveal that the CDs contain the chemical groups of N-H, C–OH/C–O–C and –COOH, etc. In addition, the diameter of the CDs is in the range of 6~8 nm. The phase transition behavior of PCEC/CDs hydrogel can be still kept and its viscoelasticity hydrogel is improved by approximatively 7%. Furthermore, friction coefficient of the released solution from composite PCEC/CDs hydrogel decreases by about 70% than that of PBS. Besides, the wear condition can be improved by a lubricating transfer film formed by released CDs. This novel strategy for slow-release application is valuable for drug delivery and bio-tribology.