Rapid Sonochemically-Assisted Green Synthesis Of Highly Stable And Biocompatible Platinum Nanoparticles As Novel Contrast Agent For Computed Tomography
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Date
2021-05
Authors
Jameel, Mahmood Subhi
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Publisher
Universiti Sains Malaysia
Abstract
Platinum nanoparticles (Pt NPs) have some intrinsic properties, including good resistance to corrosion, chemical attacks, high surface area to volume ratio and hold massive potential to be strong contenders for CT imaging contrast agent due to their advantages of high X-ray absorption. However, the synthesis methods of Pt NPs as a contrast agent for CT imaging require elaborate preparation, use of hazardous and expensive chemicals and modified Pt NPs using different chemical materials (inorganic and organic) to improve their stability and biocompatibility. Herein, a simple and facile plant-directed preparation of Pt NPs was achieved to improve the Hounsfield (HU) values for CT imaging. A highly-stable, biocompatible and ultrasmall Pt NPs with a mean core size of 5 ±1.5 nm was obtained through one step, one-pot, user-friendly, and straightforward method using Prosopis farcta fruits extract (P. farcta) as reducing agent and stabilizer using a sonochemical synthesis. A Vibra-Cell ultrasonic solid horn with a ½ inch tip size, 20 kHz frequency, 750 watts power output and 40% amplitude was used in the sonochemical synthesis of Pt NPs. The formation of amorphous or crystalline Pt NPs is attributed to the sonication's cavitation microbubbles' rapid heating/cooling cycles. The purity, uniformity and crystallinity of Pt NPs synthesized by the sonochemical method were better than those obtained from the conventional (reduction) method. The Pt NPs also exhibited smaller particle size with higher colloidal stability and uniform hydrodynamic size. The results confirmed that the sonochemical method's irradiation power enhances the crystalline properties of nanoparticles and hinders their agglomeration, evident by a zeta potential value of −38.9 mV. The high stability and biocompatibility of the Pt NPs can be attributed to the organic compounds contained in the P. farcta extract. The organic compound-conjugated Pt NPs are also identified (Oxirane, 2,3-dimethyl-, trans-, Oxirane, 2.3-dimethyl-, cis-, acetic acid, diisooctyl phthalate, phthalic acid, and di[2-propylpentyI]ester). The high energy produced by ultrasound irradiation is believed to have facilitated a ligand interaction between the P. farcta extract and the Pt NPs despite the short duration (30 minutes) of synthesis. Results showed that the cell viability of the synthesized Pt NPs is unaffected (nontoxic) at relatively high concentrations (150 μg mL-1). The X-ray attenuation of the as-synthesised NPs was 70% higher than Omnipaque (a popular iodine-based CT contrast agent currently used in the clinic), HU value of as-synthesized Pt NPs was 246 at 7.2 mg mL-1, while HU value of Omnipaque was 178 at 7.2 mg mL-1. This work gives new insights into plants' use to prepare novel contrast agents in future molecular imaging, thereby making it a promising method for synthesizing Pt NPs relevant for medical applications.
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Physics