Understanding the interaction of graphene oxide (GO) with a lipid membrane is important for the development of tissue engineering and to advance graphene-based biology. In an effort to understand the GO-lipid membrane interaction, appropriate characterisation of GO structure was determined by using X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR) and a field emission scanning electron microscope (FESEM). In this study, the lipids 1,2-dipalmitoyl-sn-glycero-3phosphocholine (DPPC) and 1,2-dioleoyl-sn-glycero-3-phosphocholine (DOPC) were used to produce a lipid vesicle with a conventional gentle hydration method and observed under transmission electron microscopy (TEM). Lipid vesicle-GO interactions were also investigated using dynamic light scattering (DLS) (Malvern Zeta) and TEM by focusing on the effect of the surface charge interactions and localisation of GO on the surface of the vesicle membrane. It was observed that the surface charge of the vesicles increased as the GO nanoparticle concentration increased, but for the low saturation lipid the surface charge remained high as the nanoparticle concentration increased. The localisation and positioning of the GO nanoparticles in the lipid vesicles were confirmed with TEM analysis.

In this research, hydroxyapatite (HA) nano-size powder was synthesized using wet chemical precipitation technique under atmospheric pressure where calcium hydroxide (Ca(OH) 2 ) and ortho-phosphoric acid (H 3 PO 4 ) were used as precursors. Distilled water was used as a diluting media for the reaction and sodium hydroxide (NaOH) was used to control the initial pH. The initial pH values, reaction temperature and calcined temperature play an important role in the morphology on HA as well as the phase formation and degree of crystallinity. Nano HA powder has been studied at different initial pH value which is between 9.00 to 11.00, reaction temperature from 80 °C to 100 °C and calcined temperature at 700 °C to 800 °C. The optimum initial pH value was found at pH 10.00, reaction temperature at 100 °C and calcined temperature was at 800 °C. The crystallographic properties were evaluated by X-ray diffraction (XRD), Fourier Transform Infrared (FTIR) and Field Emission Scanning Microscope (FESEM). The Design Expert version 9.0.2 with statistical and graphical analysis of the result, by using analysis of variance (ANOVA) was applied to optimize variable in the process of synthesis of HA. Based on analysis of variance (ANOVA) that has been perform, calcined temperature was to be influential variables on mass of HA with value of probability less than 0.05. Keywords: hydroxyapatite, chemical precipitation, crystallinity, morphology, optimization AbstrakDalam kajian ini, nanozarah hidroksiapatit (HA) dihasilkan melalui kaedah pemendakan di bawah tekanan atmosfera di mana kalsium hidroksida (Ca(OH) 2 ) dan asid orto fosforik (H 3 PO 4 ) merupakan larutan asas bagi penyediaan HA. Air suling digunakan sebagai agen pelarut dalam menyediakan larutan asas bagi proses pemendakan ini. Larutan natrium hidroksida di gunakan bagi mengawal nilai pH. Nilai pH, suhu tindak balas dan suhu relau merupakan faktor penting dalam pencirian dan penghabluran nanozarah HA. Nanozarah HA disediakan pada nilai pH antara 9.00 hingga 11.00, suhu tindak balas 80 °C hingga 100 °C dan suhu relau pada 700 °C hingga 800 °C. Pencirian nanozarah HA di uji menggunakan X-ray Difractometer (XRD), Inframerah Transformasi Fourier (FTIR), dan Mikroskop Pengimbas Pancaran Medan (FESEM). Perisian Design-Expert 9.0.2 digunakan untuk menganalisis data dan pengoptimuman penghasilan mendakan HA. Berdasarkan analisis varian (ANOVA) yang dilakukan, suhu relau merupakan pemboleh ubah yang mempengaruhi berat HA dengan nilai kemungkinan kurang dari 0.05.Kata kunci: hikdroksiapatit, mendakan bahan kimia, penghabluran, pencirian, pengoptimuman IntroductionTissue disease and defect, and bone disease are serious health condition that can affect the life for those who suffer on it. Since last four decades, various revolution has been introduced in order to make improvement of the uses of