Siti Sunarintyas

The Effect of Zirconia in Hydroxyapatite on Staphylococcus epidermidis Growth

Synthetic hydroxyapatite (HA) has been widely used and developed as the material for bone substitute in medical applications. The addition of zirconia is needed to improve the strength of hydroxyapatite as the bone substitute. One of the drawbacks in the use of biomedical materials is the occurrence of biomaterial-centred infections. The recent method of limiting the presence of microorganism on biomaterials is by providing biomaterial-bound metal-containing compositions. In this case, S. epidermidis is the most common infectious organism in biomedical-centred infection. Objective. This study was designed to evaluate the effect of zirconia concentrations in hydroxyapatite on the growth of S. epidermidis. Methods and Materials. The subjects of this study were twenty hydroxyapatite discs, divided into four groups in which one was the control and the other three were the treatment groups. Zirconia powder with the concentrations of 20%, 30%, and 40% was added into the three different treatment groups. Scanning electron microscope analysis was performed according to the hydroxyapatite and hydroxyapatite-zirconia specimens. All discs were immersed into S. epidermidis culture for 24 hours and later on they were soaked into a medium of PBS. The cultured medium was spread on mannitol salt agar. After incubation for 24 hours at 37°C , the number of colonies was measured with colony counter. Data obtained were analyzed using the ANOVA followed by the pairwise comparison. Result. The statistical analysis showed that different concentrations of zirconia powder significantly influenced the number of S. epidermidis colony (P < 0.05) . Conclusion. The addition of zirconia into hydroxyapatite affected the growth of S. epidermidis. Hydroxyapatite with 20% zirconia proved to be an effective concentration to inhibit the growth of S. epidermidis colony.

Evaluation of various alloys for stent on platelet aggregation activity

Nowadays coronary artheroslerotic disease becomes a primary health problem due to its high morbidity and mortality rate. Such disease is related to the poor coronary blood flow quality. Coronary stent implantation is widely accepted to overcome the problem. There are various alloys available for stent commercially by different prices. This study was aimed to evaluate the various alloys for stent on platelet aggregation activity. The materials used under reseach were stainless-steel of SS 316L (Otocompo, Sweden) and cobalt-chromium of CoCr L605 (Remanium Star, Germany). Twenty eights alloys (14 SS 316L and 14 CoCr L605) were shaped as discs with 10 mm diameter and 2 mm thickness respectively. Venous blood was drawn from medial cubiti vein from 14 subjects of healthy people with neither established atherosclerotic disease nor risk factors. The drawn blood from each subject further be divided into three parts: one part was left without any induction (control), the other two parts were contacted to SS 316L and CoCr L605 respectively. Platelet aggregation activity in all of the samples were then calculated and analyzed by Anova. The result showed the average of platelet aggregation activity in percentage (%) were 89.96±17.93 (control), 80.16±22.04 (CoCr L605), and 80.91±20.68 (SS 316L). The Anova showed p>0.05. In conclusion, stainless-steel of SS 316L and cobalt-chromium of CoCr L605 did not affect platelet aggregation activity on healthy subject; therefore, both of the alloys were potential to be used as material choices for stent devices. Further research is needed to evaluate the effect of both alloys on atherosclerotic patients.

The effect of sericin application over hydroxyapatite surface on osteoblast cells proliferation

Hydroxyapatite (HA) has been used clinically to treat bone defect. Modification of HA surface with respect to bone integration has been developed using treatments which have the potential to improve cells proliferation. Bombyx moris sericin, a polymer protein that has polar side groups, have been known to accelerate cells attachment and proliferation. The aim of this study was to investigate the effect of sericin application over HA surface on osteoblast cells proliferation. HA discs (10 mm in diameter, 3 mm thick) were sintered. Three concentration of sericin (0.01, 0.5, and 0.1%) were applied on HA surface. Water contact angle was measured to evaluate the hydrophilicity of the disc surface. The discs were then seeded with MC3T3E1 osteoblast cells for proliferation test. The data were analyzed by Anova and LSD. Contact angle measurement showed significant increases of the hydrophilicity on sericin-modified HA surface. The amount of cells proliferation on HA discs (1.40±0.26) was significantly difference (p&#60;0.05) with HA+sericin 0.01% (2.23±0.20), HA+sericin 0.5% (2.33±0.24), HA+sericin 0.1% (2.37±0.20). Variation of sericin concentrations applied over HA did not influence any significant difference on cells proliferation (p>0.05). The conclusion was sericin application over HA surface increased the amount of osteoblast cells proliferation. Concentration of sericin application over HA (0.01, 0.05, 0.1%) did not influence cells proliferation.

Bioadhesion of Biomaterials

Biomaterials are widely used in many kinds of medical devices. The biomaterials used can be metal, polymer, ceramic or composites. Bioadhesion will be occured when the medical device contact to biological surface. There are many conditions where bioadhesion is beneficial and vice versa. The implantation of medical devices in the human body is not without risk. It is reported that implantable medical devices are an ideal interface for microorganisms. There are infections caused mainly by bacteria originating in the body. Some aspects influence bioadhesion of implantable medical devices including surface topography, chemical interaction, mechanical interaction and physiological interactions are discussed. The understanding of such aspects hopefully governs medical practitioners in controlling the medical devices bioadhesion process, then optimizing the desirable bioadhesion and removing the undesirable interactions. To complete the discussion on bioadhesion of biomaterials, it is also described some methods of bioadhesion testing including surface roughness measurement, contact angle measurement, surface topography evaluation and biofilm formation testing. At last, a perspective related to biomaterials used as medical devices is presented.

Cytotoxicity of Cricula triphenestrata Cocoon Extract on Human Fibroblasts

Objectives. The aim of this paper was to evaluate the cytotoxicity of Indonesian silkworm cocoon extract of Cricula triphenestrata on human fibroblasts. Methods and Materials. The cocoon shells of the silkworm Cricula triphenestrata were degumming. The shells were mixed with an aqueous solution of 0.3% Na2CO3 at 98°C for 1 hour. The solution was then dialyzed in cellulose membranes against deionized water for 3 days. The cocoon shells extract powder was collected via rotary evaporation and dried under freeze dryer. Cell culture medium was exposed to Cricula triphenestrata cocoon extract (0.01–100 μg/mL) for 24 hours. The primary human gingival fibroblasts were exposed to the treated cell culture medium for 24 hours. Cytotoxicity evaluation was done by MTT method. The data were analyzed by one-way ANOVA. Result. The result revealed no significant cytotoxicity of Cricula triphenestrata cocoon extract against human fibroblasts at a concentration up to 100 μg/mL (P > 0.05). Conclusion. Cricula triphenestrata cocoon extract was not cytotoxic on human gingival fibroblast cells.