Increasing the Strength of the Micro-bubble by Encapsulating with Silica

Öz

From the past to the present, comprehensive research has been conducted to develop effective and stable contrast agents within the body for various medical applications. Particularly, microbubbles (MBs) that exhibit high contrast capabilities during medical ultrasound imaging have garnered attention. These MBs deform when the gas core is compressed and when they interact with blood in the capillaries under ultrasound exposure. The deformation of MBs, characterized by the contraction-expansion movements of the MBs shell, has made them a widely used contrast agent. The core and shell structure of MBs significantly influence their stability and, consequently, their effectiveness. Studies in the literature have shown that MBs with gas cores having different Q values are encapsulated with materials such as lipids, proteins, polymers, and surfactants. These encapsulated MBs are expected to possess structural stability, effective particle size, and high contrast simultaneously to be suitable for medical ultrasound imaging. In this study, previously unexplored n-pentane (C5) and perfluoropropane (C3H8), were encapsulated within silica (SiO2) using the sol-gel method to obtain stable MBs ranging in size from 1 to 5 micrometers for use as contrast agents. It was determined that the optimal surfactant concentration for SiO2-C5 was 10% by weight and increasing the ammonia catalyst resulted in a decrease in the average hydrodynamic particle size. The SiO2-C5 systems, as ideally determined, maintained their stability for 7 days in emulsion and 10 minutes in contact with air. For the SiO2-C3H8 systems, it was observed that increasing the core structure amount resulted in a decrease in the average hydrodynamic particle size. These systems maintained their stability for up to 15 days in emulsion and 15 minutes when exposed to air.

Anahtar Kelimeler

• Contrast agent
• Micro bubble
• Micro capsule
• Silica

Mikro-Kabarcığın Silika ile Kapsüllenerek Mukavemetinin Artırılması

Öz

Geçmişten günümüze çeşitli tıbbi uygulamalarda kullanılmak üzere, vücut içinde etkin ve stabil kontrast ajanlarının geliştirilmesi için kapsamlı araştırmalar yapılmıştır. Özellikle tıbbi ultrason görüntüleme esnasında yüksek kontrast sağlayabilme yetenekleri ile dikkat çeken mikro-kabarcıklar (MBs), gaz çekirdeklerinin sıkıştırılması ve kanın ultrasonla etkileşimi sonucu deforme olarak, MBs’ nin kabuğundaki büzülme-genleşme hareketleri ile yaygın bir kontrast ajanı olarak kullanılmaktadır. MBs’ nin kabarcıkların çekirdek ve kapsül yapısı, kabarcığın stabilitesini ve bununla beraber etkinlik süresine etki etmektedir. Literatürdeki çalışmalar, farklı Q değerlerine sahip gaz çekirdek yapılı MBs’ nin lipit, protein, polimer ve sürfaktan gibi malzemelerle kapsüllendiğini göstermektedir. Bu kapsülasyon malzemeleri ile oluşturulan MBs’ nin ise tıbbi ultrasonik görüntülemede kullanılabilmesi için yeterli yapısal stabiliteye, etkin parçacık boyutuna ve yüksek kontrasta aynı anda sahip olması beklenmektedir. Bu araştırmada ise daha önce literatürde çalışılmamış olan n-pentan (C5) ve perfloropropan (C3H8) gazlarının sol-jel yöntemiyle silika (SiO2) kapsülasyonu yapılarak, 1-5 mikrometre arasında stabil MK elde edilmesi ve kontrast ajanı olarak kullanılması hedeflenmiştir. SiO2-C5 için en uygun sürfaktan miktarının ağırlıkça %10 olduğu belirlenmiş olup, amonyak katalizörünün artırılması ile ortalama hidrodinamik partikül boyutunun ise azaldığı gözlemlenmiştir. İdeal olarak belirlenen SiO2-C5 sistemleri, emülsiyon içinde 7 gün, hava ile etkileşiminde ise 10 dakika boyunca stabilitesini koruduğu görülmüştür. SiO2-C3H8 sistemleri için, çekirdek yapı miktarının arttırılması ile ortalama hidrodinamik parçacık boyutunun azaldığı, 15 güne kadar emülsiyon içinde, 15 dakika hava ile etkileşimi sonrasında stabilitesini koruduğu görülmüştür.

Anahtar Kelimeler

• Kontrast ajanı
• Mikro kabarcık
• Mikro Kapsül
• Silika
• Sol-Jel

Destekleyen Kurum

Bu araştırmayı FYL-2021-5550 proje numarası ile destekleyen Akdeniz Üniversitesi Bilimsel Araştırma Projeleri Koordinasyon Birimine teşekkür ederiz.

Etik Beyan

Çalışma tüm etik standartlara uygundur.

Teşekkür

Akdeniz Üniversitesi personeline ve yönetimine bu çalışmadaki yardımları ve destekleri için içtenlikle teşekkür ederiz.

Kaynakça

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