Nanotechnology as a Versatile Tool for 19F-MRI Agent’s Formulation: A Glimpse into the Use of Perfluorinated and Fluorinated Compounds in Nanoparticles

Abstract

Simultaneously being a non-radiative and non-invasive technique makes magnetic resonance imaging (MRI) one of the highly sought imaging techniques for the early diagnosis and treatment of diseases. Despite more than four decades of research on finding a suitable imaging agent from fluorine for clinical applications, it still lingers as a challenge to get the regulatory approval compared to its hydrogen counterpart. The pertinent hurdle is the simultaneous intrinsic hydrophobicity and lipophobicity of fluorine and its derivatives that make them insoluble in any liquids, strongly limiting their application in areas such as targeted delivery. A blossoming technique to circumvent the unfavorable physicochemical characteristics of perfluorocarbon compounds (PFCs) and guarantee a high local concentration of fluorine in the desired body part is to encapsulate them in nanosystems. In this review, we will be emphasizing different types of nanocarrier systems studied to encapsulate various PFCs and fluorinated compounds, headway to be applied as a contrast agent (CA) in fluorine-19 MRI (19F MRI). We would also scrutinize, especially from studies over the last decade, the different types of PFCs and their specific applications and limitations concerning the nanoparticle (NP) system used to encapsulate them. A critical evaluation for future opportunities would be speculated.

Fluorinated Human Serum Albumin as Potential 19F Magnetic Resonance Imaging Probe

“…Recently, 19 F electron nuclear double resonance (ENDOR) spectroscopy was evaluated for distance measurement between a spin probe and a fluorine label [ 31 , 32 , 33 ]. Fluorine-based tracer construction can be engineered to contain polymers [ 34 , 35 ] and nanoparticles [ 29 , 30 , 35 , 36 , 37 , 38 ] for cancer [ 35 , 39 , 40 ], Alzheimer’s disease, amyloid-β [ 41 , 42 , 43 ], neuro disorders [ 44 ], inflammation [ 45 ], and other various pathological conditions [ 26 ]. Improvements in 19 F MRI equipment combined with the development of novel, sensitive probes will decrease the global disease burden.…”

Shortwave Infrared Fluorofluorophores for Multicolor In Vivo Imaging**

“…We expect the F 68 Chrom5 and F 68 Chrom7 fluorofluorophores will continue to advance our knowledge of PFC nanomaterials in vivo as well as be applied to emerging applications of PFCs such as in vivo mechanical force measurements [18] and droplet-based sensors. [63]…”

“…Notable results from the paired PFC nanoemulsion experiments include 1) 300 nm emulsions display significant localization in the spleen over the liver and 2) altering the surfactant from the traditional poly(ethylene glycol) to poly(methyl‐2‐oxazoline) results in decreased liver accumulation. We expect the F 68 Chrom5 and F 68 Chrom7 fluorofluorophores will continue to advance our knowledge of PFC nanomaterials in vivo as well as be applied to emerging applications of PFCs such as in vivo mechanical force measurements [18] and droplet‐based sensors [63] …”

Shortwave infrared fluorofluorophores for multicolor in vivo imaging

“…We expect the F68Chrom5 and F68Chrom7 fluorofluorophores will continue to advance our knowledge of PFC nanomaterials in vivo as well as be applied to emerging applications of PFCs such as in vivo mechanical force measurements [18] and droplet-based sensors. [58]…”