Sains Malaysiana 47(6)(2018): 1235–1240

http://dx.doi.org/10.17576/jsm-2018-4706-19

Effect of Gamma Irradiation on the Physical Stability of DPPC Liposomes

(Kesan Sinaran Gama ke atas Kestabilan Fizikal Liposom DPPC)

LIYANA MOHD ALI NAPIA¹, IRMAN ABDUL RAHMAN^1,2*, MOHD YUSOF HAMZAH³,

FAIZAL MOHAMED^1,2, HUR MUNAWAR KABIR MOHD¹, INTAN SYAKEELA AHMAD BASTAMAM¹, SHAMELLIA SHARIN¹, NORSYAHIDAH MOHD HIDZIR^1,2

& SHAHIDAN RADIMAN^1,2

¹School of Applied Physics, Faculty of Science and Technology, Universiti Kebangsaan Malaysia 43600 UKM Bangi, Selangor Darul Ehsan, Malaysia

²Nuclear Technology Research Center, School of Applied Physics, Faculty of Science and Technology Universiti Kebangsaan Malaysia 43600 UKM Bangi, Selangor Darul Ehsan

Malaysia

³Nanotechnology Laboratory Radiation Technology Division, Agensi Nuklear Malaysia

43000 Kajang, Selangor Darul Ehsan, Malaysia

Received: 15 September 2016/Accepted: 17 March 2017

ABSTRACT

Unilamellar liposomes composed of dipalmitoylphosphatidylcholine (DPPC) were prepared by the reverse-phase evaporation method and extrusion through a polycarbonate membrane filter. Liposomes at 0.7 mg/mL lipid concentration in deionized water were exposed to gamma irradiation at a dose in the range 0.5 to 25 kGy. Gamma irradiation of liposomes resulted in the degradation of DPPC lipids into free fatty acids, lysophosphatidylcholine and 1,2-palmitoyl-phosphatidic acid (DPPA). The effect of gamma irradiation towards the physical stability of liposomes was investigated by means of dynamic light scattering (DLS), transmission electron microscopy (TEM) and zeta potential analysis. From the DLS analysis, no significant changes were observed in the hydrodynamic size of liposomes. TEM images indicate that the liposomes surface became smoother and rounder as higher irradiation doses were applied. Zeta potential analysis showed that gamma irradiation of DPPC liposomes at radiation doses as low as 0.5 kGy resulted in a drastic rise in the magnitude of the zeta potential. The results also demonstrate that gamma irradiation of liposomes suspension enhanced the overall stability of liposomes. Hence, it can be concluded that gamma irradiation on DPPC liposomes may potentially produce liposomes with higher stability.

Keywords: Dipalmitoylphosphatidylcholine (DPPC); gamma irradiation; physical stability; zeta potential

ABSTRAK

Liposom unilamela yang terbentuk daripada lipid dipalmitoilfosfatidilkolina (DPPC) telah dihasilkan menggunakan kaedah penyejatan fasa-berbalik dan penerobosan menerusi turas membran polikarbonat. Ampaian liposom dengan kepekatan lipid 0.7 mg/mL di dalam air ternyah ion dipancarkan sinaran gama pada dos 0.5 hingga 25 kGy. Penyinaran gama ke atas liposom menyebabkan degradasi lipid DPPC kepada asid lemak bebas, lisofosfatidilkolina dan 1,2-palmitoil-asid fosfatidik (DPPA). Kesan penyinaran gama terhadap kestabilan fizikal liposom dikaji menggunakan analisis penyerakan cahaya dinamik (DLS), mikroskop elektron transmisi (TEM) dan penganalisis keupayaan zeta. Daripada analisis DLS, tiada perubahan pada saiz liposom dapat dikenal pasti. Imej TEM menunjukkan bahawa permukaan liposom semakin licin dan semakin membulat apabila semakin tinggi dos penyinaran dikenakan ke atas liposom. Analisis keupayaan zeta mendedahkan bahawa penyinaran gama ke atas liposom DPPC pada dos serendah 0.5 kGy menyebabkan peningkatan drastik terhadap magnitud keupayaan zeta. Hasil analisis ini juga menunjukkan bahawa penyinaran gama ke atas ampaian liposom berupaya untuk meningkatkan kestabilan liposom. Oleh itu, penyinaran gama ke atas liposom DPPC boleh menghasilkan liposom yang berkestabilan tinggi.

Kata kunci: Dipalmitoilfosfatidilkolina (DPPC); kestabilan fizikal; keupayaan zet; penyinaran gama

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*Corresponding author; email: irman@ukm.edu.my