Effect of protein concentrations of bovine serum albumin and 관-globulin on the frictional response of a cobalt-chromium femoral head.

Duong, Cong-Truyen,Lee, Jae-Hoon,Cho, Younho,Nam, Ju-Suk,Kim, Hyong-Nyun,Lee, Sang-Soo,Park, Seonghun Chapman and Hall ; Kluwer Academic Publishers 2012 Journal of materials science, Materials in medicin Vol.23 No.5

<P>The study aims to identify the concentration-dependent role of bovine serum albumin (BSA) and 관-globulin in the lubricating ability of a cobalt-chromium femoral head. The frictional coefficients of the cobalt-chromium femoral head decreased with increasing BSA concentrations from 10 to 40 mg/ml and showed statistical differences between any of the BSA concentration groups, except between the 30 and 40 mg/ml concentration groups. In 관-globulin, the frictional coefficients significantly decreased at concentrations of 2.5 and 5.0 mg/ml as compared with the PBS control group, but significant increases were observed at 7.5 and 12.5 mg/ml. These results suggest that the friction of the cobalt-chromium femoral head is dependent on the concentration of both BSA and 관-globulin. However, there is a maximum concentration for BSA to act as an effective boundary lubricant, while the lubricating ability of 관-globulin is most effective in the physiological concentration range within human synovial fluid.</P>

Effect of Tip Geometry of Atomic Force Microscope on Mechanical Responses of Bovine Articular Cartilage and Agarose Gel

Park, Seong-Hun,Duong, Cong-Truyen,Lee, Jae-Hoon,Lee, Sang-Soo,Son, Kwon 한국정밀공학회 2010 International Journal of Precision Engineering and Vol.11 No.1

The objective of this study is to investigate the effect of different Atomic Force Microscope (AFM) tip geometries (sharp-conical and spherical tips) on the microscale Young's modulus of bovine articular cartilage and agarose gel that is calculated by the method of the average point-wise modulus. The measurements of the microscale Young's moduli of 3% agarose gel under a conical AFM tip ($20.9{\pm}4.9\;kPa$) and under a spherical AFM tip ($17.5{\pm}3.0\;kPa$), averaged over an indentation depth of 600 nm, were comparable. However, the microscale Young's moduli of articular cartilage, as measured with a conical AFM tip ($116.9{\pm}62.9\;kPa$), were significantly higher than the corresponding values under a spherical AFM tip ($30.9{\pm}14.3\;kPa$). The results of the current study suggest that the AFM tip geometry affects the microscale measurements of the mechanical properties on the surfaces of biological materials. The findings of the study can help to elucidate more accurately the microscale mechanical properties on the surface layers of diverse biological materials including tissue-engineered cartilages with different material characteristics.

표면 윤활 물질에 의한 인공 고관절 코발트-크롬 대퇴골두의 마찰 및 윤활 반응

박성훈 ( Seong Hun Park ),( Duong Cong Truyen ),이재훈 ( Jae Hoon Lee ),조윤호 ( Youn Ho Cho ),박승재 ( Seung Jae Park ),박근민 ( Keun Min Park ),장준동 ( Jun Dong Chang ),이상수 ( Sang Soo Lee ) 대한고관절학회 2010 Hip and Pelvis Vol.22 No.3

목적: 인공 고관절에서 알부민의 경계윤활제로서의 영향을 나노 단위 수준에서 확인하기 위하여, 코발트-크롬 대퇴골두를 AFM (Atomic Force Microscope) 을 사용하여 마찰 관련 지표의 변화를 분석하였다. 대상 및 방법: 환자의 코발트-크롬 대퇴골 삽입물의 마모된 부위로부터 실험 모델을 제작하였다. 사용된 윤활제는 대조용액으로 PBS (Phosphate Buffered Saline)가 사용되었으며 실험용액으로는 우혈청 알부민(BSA: Bovine Serum Albumin)가 사용되었다. 결과: 마찰계수 (μ)는 실험군과 대조군 사이의 마찰계수가 통계적으로 유의하였다(10 mg/ml, 20 mg/ml, 30 mg/ml, 40 mg/ml BSA: P<0.001). 각 농도의 BSA 혼합 용액 사이에서도 통계적으로 유의한 마찰계수의 차이를 보였으며, 30 mg/ml와 40 mg/ml사이에서는 마찰계수의 차이가 유의하지 않았다. 결론: 코발트-크롬 대퇴골두의 표면에 흡착되어서 경계 윤활 작용의 효과를 극대화 시킬 수 있는 효과적인 단백질 농도가 존재한다. Purpose: This study aimed at investigating the role of albumin as a boundary lubricant in the lubrication of the Co-Cr femoral head of artificial hip implants by measuring the tribological parameters of the Co-Cr femoral head with Atomic Force Microscope (AFM) techniques. Materials and Methods: Samples were prepared from the main wear region of a Co-Cr femoral head from revision hip surgery. Two types of solutions were prepared as lubricants: PBS (Phosphate Buffered Saline) as a control solution and BSA (Bovine Serum Albumin) as a lubricant at concentrations of 10, 20, 30 and 40 mg/ml in PBS solution. Results: There were statistically significant differences in the frictional coefficients (μ) of a Co-Cr head between the PBS control and all the concentrations of BSA (10, 20, 30, 40 mg/ml) (P<0.001). Similarly, there were statistically significant differences for the μ between the BSA concentrations of 10, 20, 30 and 40 mg/m for all the cases except between the BSA of 30 and 40 mg/ml (P<0.01). Conclusion: There exists a maximum protein concentration of BSA to play a role as an effective boundary lubricant through adsorption on the surface of Co-Cr femoral head.

Role of hyaluronic acid and phospholipid in the lubrication of a cobalt-chromium head for total hip arthroplasty.

Park, Jong-Bong,Duong, Cong-Truyen,Chang, Ho-Geun,Sharma, Ashish R,Thompson, Mark S,Park, Sungchan,Kwak, Byung-Chan,Kim, Tae-Young,Lee, Sang-Soo,Park, Seonghun American Vacuum Society 2014 Biointerphases Vol.9 No.3

<P>The tribological performance of total hip arthroplasty has an important influence on its success rate. This study examined the concentration-dependent role of hyaluronic acid (HA) and phospholipid (dipalmitoylphosphatidylcholine, DPPC) in the boundary lubricating ability of retrieved cobalt-chromium femoral heads. The microscale frictional coefficients (μ) were measured by atomic force microscopy using a rectangular silicon cantilever integrated with sharp silicon tips. In the case of HA lubricant, the frictional coefficients decreased significantly at concentrations of 2.0 (0.16??0.03) and 3.5?mg/ml (0.11??0.01) while increased at 5.0?mg/ml (0.15??0.01), compared to that with phosphate buffer saline (0.25??0.03). The concentration-dependent lubrication behavior of DPPC was most effective when DPPC was in the physiological concentration range, showing μ?=?0.16??0.01 in polypropylene glycol, and 0.05??0.01, 0.02??0.01, and 0.03??0.01 at a DPPC concentration of 0.05, 0.2, and 3.0?mg/ml, respectively. Results obtained show significant differences between the DPPC concentration groups. Conclusively, the microscale frictional response of the retrieved CoCr femoral head has a significant dependence on the concentrations of HA and DPPC. Moreover, observed optimal concentration of HA and DPPC for effective lubrication is similar to that observed in normal human synovial fluid. Therefore, a retrieval of the synovia may be considered during total hip replacement surgeries in an effort for reduction of friction between head and liner of total hip replacement implants.</P>

Tribological changes in the articular cartilage of a human femoral head with avascular necrosis.

Seo, Eun-Min,Shrestha, Suman K,Duong, Cong-Truyen,Sharma, Ashish Ranjan,Kim, Tae-Woo,Vijayachandra, Ayyappan,Thompson, Mark S,Cho, Myung Guk,Park, Sungchan,Kim, Kwanghoon,Park, Seonghun,Lee, Sang-Soo American Vacuum Society 2015 Biointerphases Vol.10 No.2

<P>The present study evaluated the tribological properties of the articular cartilage surface of the human femoral head with postcollapse stage avascular necrosis (AVN) using atomic force microscopy. The cartilage surface in the postcollapse stage AVN of the femoral head was reported to resemble those of disuse conditions, which suggests that the damage could be reversible and offers the possibilities of success of head-sparing surgeries. By comparing the tribological properties of articular cartilage in AVN with that of osteoarthritis, the authors intended to understand the cartilage degeneration mechanism and reversibility of AVN. Human femoral heads with AVN were explanted from the hip replacement surgery of four patients (60-83 years old). Nine cylindrical cartilage samples (diameter, 5 mm and height, 0.5 mm) were sectioned from the weight-bearing areas of the femoral head with AVN, and the cartilage surface was classified according to the Outerbridge Classification System (AVN0, normal; AVN1, softening and swelling; and AVN2, partial thickness defect and fissuring). Tribological properties including surface roughness and frictional coefficients and histochemistry including Safranin O and lubricin staining were compared among the three groups. The mean surface roughness Rq values of AVN cartilage increased significantly with increasing Outerbridge stages: Rq = 137 26 nm in AVN0, Rq = 274 49 nm in AVN1, and Rq = 452 77 nm in AVN2. Significant differences in Rq were observed among different Outerbridge stages in all cases (p < 0.0001). The frictional coefficients (μ) also increased with increasing Outerbridge stages. The frictional coefficient values were μ = 0.115 0.034 in AVN0, μ = 0.143 0.025 in AVN1, and μ = 0.171 0.039 in AVN2. Similarly to the statistical analysis of surface roughness, significant statistical differences were detected between different Outerbridge stages in all cases (p < 0.05). Both surface roughness and frictional coefficient of cartilage, which were linearly correlated, increased with increasing Outerbridge stages in postcollapse AVN. The underlying mechanism of these results can be related to proteoglycan loss within the articular cartilage that is also observed in osteoarthritis. With regard to the tribological properties, the cartilage degeneration mechanism in AVN was similar to that of osteoarthritis without reversibility.</P>