Nayera Mohamed Ali El Ghoubary,  <br/><br/>
Pharmaceutical study of the photobiological and photothermal properties of sepia melanin nanoparticles / 
 دراسة صيدلانية للخواص الضوئية البيولوجية و الحرارية للجزيئات النانوية لميلانين الحبار / 
by Nayera Mohamed Ali El Ghoubary ; Supervisors Prof. Dr. Maha Fadel Mohamed, Prof. Doaa Ahmed Abdel Fadeel.  
 - 114 pages :  illustrations ;  25 cm. +   CD. 
<br/><br/>Thesis (Ph.D)-Cairo University, 2024. 
<br/><br/>Bibliography: pages 100-114.  
<br/><br/> Melanin is a natural photothermal biopolymer. It is considered the main chromophore for laser hair <br/>removal. The insolubility of melanin as an exogenous dye, in most solvents, limits its bioavailability and <br/>thus its clinical use. Melanin was extracted from a sepia ink sac and prepared as insoluble powdered sepia <br/>melanin (SM) which is identified by FTIR, 1H-NMR, thermogravimetric analysis (TGA), and scanning <br/>electron microscope (SEM). In our study, to overcome the solubility problems and increase the <br/>bioavailability of melanin for biomedical and cosmetic applications, SM was self-assembled using tween <br/>80 into dispersed nanoparticles (SM-NP-Tw). Moreover, natural sepia melanin was loaded in different <br/>delivery systems (spanlastics and transfersomes) to be delivered to the hair follicles. The prepared SM-NP-<br/>Tw were fully characterized. The photothermal performance of SM-NP-Tw was assessed. Dark and <br/>photocytotoxicity of SM-NP-Tw was studied on HepG2 cells using two wavelengths (660 nm and 820 nm). <br/>The insoluble powdered (SM) exhibited a spherical nanoparticle-like shape as revealed by scanning electron <br/>microscope and was soluble only in an alkaline aqueous solution. TGA of SM showed high resistance to <br/>thermal degradation indicating good thermal stability. The prepared SM-NP-Tw exhibited a spherical shape <br/>with mean sizes of 308±86 nm and a zeta potential of −25 mv. The cell viability decreased significantly <br/>upon increasing the concentration and upon radiation at 820 nm. The results of UV–Vis spectroscopy and <br/>the photothermal performance revealed that melanin can absorb light in a wide range of wavelengths <br/>including near the IR region; thus, it can emit sufficient heat to kill cells through the photoheat conversion <br/>effects. Melanin spanlastics and transfersomes were prepared and characterized. Transmission electron <br/>microscopy (TEM) showed the spherical shape of the prepared vesicles with average particle sizes 252 and <br/>262 nm and zeta potential of -22.5 and -35 mV for melanin spanlastics and melanin transfersomes, <br/>respectively. Histological examination of hair follicles and pilosebaceous glands for the irradiated and non-<br/>irradiated albino mice skin was studied after the application of the prepared formulations topically and <br/>subcutaneously. Qualitative statistical analysis was conducted and melanin transfersomes and melanin <br/>spanlastics showed significant damage to pilosebaceous glands and hair follicles with a p-value of 0.031 <br/>and 0.009 respectively. Sepia melanin nanoparticles self-assembled into tween-based nanostructures could <br/>be a promising natural platform for different applications including photothermal cancer therapy. As well, <br/>melanin nanoparticles loaded in transfersomes and spanlastics could be considered a promising approach <br/>for the laser removal of non-pigmented hair.   إن الهدف من هذه الرسالة هو تحضير الميلانين في أنواع مختلفة من موصلات الدواء. الميلانين هو بوليمر حيوي حراري ويعتبر الكروموفور الرئيسي لإزالة الشعر بالليزر. و لكن عدم قابلية ذوبان الميلانين كصبغة خارجية ، في معظم المذيبات ، يعد مشكلة كبيرة تحد من توافره البيولوجي وبالتالي استخدامه اكلينيكيا. تم استخراج الميلانين من الحبار وتحضيره كمسحوق غير قابل للذوبان (SM) و تمت دراسته. ولكى نتغلب على مشاكل الذوبان وزيادة التوافر البيولوجي للميلانين ، تم تحضيره  في جسيمات نانوية ، وتم تحميل الميلانين في موصلات دواء مختلفة ليتم توصيل الميلانين إلى بصيلات الشعر.تم دراسة الخواص الصيدلية للميلانين و تقييم الأداء الحراري الضوئي لها. أيضا تم دراسة سمية الميلانين على الخلايا السرطانية  فى المعمل في الظلام و فى وجود الضوء باستخدام جهاز ليزربطوليين موجيين (660 نانومتر و 820 نانومتر). 
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<br/><br/><br/>Text in English and abstract in Arabic & English. 
<br/><br/><label>Subjects--Topical Terms: </label><br/>Laser Sciences
<br/><br/><label>Subjects--Index Terms: </label>Melanin  melanin nanoparticles  cancer  laser  hair removal 
<br/><br/><label>Dewey Class. No.: </label>621.366