07:53:00 AM Thursday, 21 September 2017
Bahasa  English  Others   A-  A+   Change Default Theme Change Blue Theme Change Orange Theme   Narrow Normal Wide
 

GLOBAL TESTING AND CONSULTANCY FOR RUBBER (G-TACR)

BIOLOGICAL TESTING ON GLOVES

Tajul Anuar Yaakob


Natural rubber (NR) and synthetic gloves have been widely used for barrier protection against microorganisms and harmful chemicals. Biological laboratory is responsible to evaluate the quality and further effect of the gloves residue to immune body system due to several tests such as cytotoxicity, endotoxin and virus penetration test. However, they are not accredited to MS ISO/IEC 17025.

Cytotoxicity test

Cytotoxicity test use to determine viability of cell by determining the number of living and dead cells in the total cell. The decrease in cell viability (<50%) can indicate the toxic effects of compounds or suboptimal culture conditions. This test is performed in compliance with ISO 10993-05 using mouse fibroblast L-929 Cells (normal immortal cell). The cytotoxicity test by using microtiter tetrazolium (MTT) assays to measures the reducing potential of the cell using a colorimetric reaction. Viable cells will reduce the 3-(4, 5-Dimethyl-2-thiazolyl)-2, 5-diphenyl-2H-tetrazolium bromide; MTT reagent to a colored formazan (crystal blue) product (Figure 1a). Formazan crystalize will be observed by micro plate reader (Figure 1b).

Exposure of cultured cell by MTT reagent Colorimetric observation by micro plate reader
(a)(b)
Figure 1(a) Exposure of cultured cell by MTT reagent and 1(b) Colorimetric observation by micro plate reader


Endotoxin test

Biological laboratory also provided endotoxin test performed by using Limulus amebocyte lysate (LAL). Limulus amebocyte lysate (LAL) is an aqueous extract of blood cells (amoebocytes) from the horseshoe crab. LAL reacts with bacterial endotoxin or lipopolysaccharide (LPS), which is a membrane component of Gram negative bacteria. This reaction is the basis of the LAL test, which is used for the detection and quantification of bacterial endotoxins. Lipopolysaccharide (LPS) is the major component of the outer membrane of Gram-negative bacteria which is contributing greatly to the structural integrity of the bacteria, and protecting the membrane from certain kinds of chemical (Figure 2 (a) and (b)). Endotoxin was determined the toxic activity of LPS that is released by bacteria into the environment. It considered being a toxin kept "within" the bacterial cell and released only after destruction of the bacterial cell wall. Endotoxin can cause irritate of the skin, induce respiratory problems, fever, and shock. Previous study shows endotoxin was found to be a highly significant contaminant of some latex gloves. The highest levels of endotoxin were found in non-sterile examination gloves with a tendency towards powdered gloves containing more endotoxin and protein.

Structure of Gram negative bacterial Gram negative bacterial cell wall
(a)(b)
Figure 2 (a): Structure of Gram negative bacterial and 2(b) Gram negative bacterial cell wall
Virus penetration test

Virus penetration test

Virus penetration test is performed in compliance with ASTM Method F1671 which is a test for resistance of material used in protective clothing to penetration by blood-borne pathogens; FX174 bacteriophage by using penetration test equipment (Figure 2(a) and (b)). The bacteriophage has been utilized as surrogate virus for human pathogenic viruses which is five times smaller than HIV, non-pathogenic to humans, stable at different temperatures and pH levels. This method was adapted to assess the effectiveness of materials used in gloves for protecting the wearer using a surrogate microbe suspended in a body fluid stimulant under conditions of continuous contact. The virus penetration will be determined the amount of virus originally present in the glove that leak throughout the poor or hole of intact or defect gloves. The virus collection will be diluted and bioassay by utilizing bacteria; Escherichia coli C as the host. The inoculated bacteria with virus were transferred onto a petri dish containing agar. The plaque formed will be measured by using a colony counter. Plaque is a visible, clear area, which is theoretically the result of the infection and lysis of host cells by a single viable virus. Plague formed will be analyzed to determine the amount of virus leakage as the plaque forming unit (pfu).

Structure of Gram negative bacterial Gram negative bacterial cell wall
(a)(b)
Figure 3(a) settup of penetration test equipment and (b) dissemble of the penetration test cell

Structure of Gram negative bacterial Gram negative bacterial cell wall
(a)(b)
Figure 4 (a) Virus and bacteria will be transferred to petri dish coated by agar and (b) plaque formed will be count with the colony counter

Home          FAQ          Copyright           Privacy & Security Policy          Sitemap          RSS Feed RSS Feed          Support