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The elemental characteristics of the fluorine atom tell us that replacing an alkyl chain by a perfluoroalkyl or polyfluorinated chain in a molecule or polymer is consequential. A brief reminder about perfluoroalkyl chains, fluorocarbons and fluorosurfactants is provided. The outstanding, otherwise unattainable physicochemical properties and combinations thereof of poly and perfluoroalkyl substances (PFASs) are outlined, including extreme hydrophobic and lipophobic character; thermal and chemical stability in extreme conditions; remarkable aptitude to self-assemble into sturdy thin repellent protecting films; unique spreading, dispersing, emulsifying, anti-adhesive and levelling, dielectric, piezoelectric and optical properties, leading to numerous industrial and technical uses and consumer products. It was eventually discovered, however, that PFASs with seven or more carbon-long perfluoroalkyl chains had disseminated in air, water, soil and biota worldwide, are persistent in the environment and bioaccumulative in animals and humans, raising serious health and environmental concerns. Further use of long-chain PFASs is environmentally not sustainable. Most leading manufacturers have turned to shorter four to six carbon perfluoroalkyl chain products that are not considered bioaccumulative. However, many of the key performances of PFASs decrease sharply when fluorinated chains become shorter. Fluorosurfactants become less effective and less efficient, provide lesser barrier film stability, etc. On the other hand, they remain as persistent in the environment as their longer chain homologues. Surprisingly little data (with considerable discrepancies) is accessible on the physicochemical properties of the PFASs under examination, a situation that requires consideration and rectification. Such data are needed for understanding the environmental and in vivo behaviour of PFASs. They should help determine which, for which uses, and to what extent, PFASs are environmentally sustainable. [ABSTRACT FROM AUTHOR]

Long-chain perfluoroalkylated acids are persistent in the environment, leading to ubiquitous exposure of biota. They have been listed as very persistent, very bioaccumulative and toxic by Public Health Authorities. Their production and use have been regulated in most western countries but their production has increased in other geographical area. Animal studies show highly diverse and complex, product-, species- and gender-dependent pharmacodynamics and toxicity profiles. Human epidemiologic studies unveiled liver, developmental and other adverse health effects, while further effects remain inconclusive. Alternative short-chain products are technically much less performing. Alternative long-chain processing aids have not been proven environmentally advantageous. Risk assessment is difficult and highly uncertain. Little breakthrough products or technologies have yet emerged that can match the feats of fluorinated surfactants and fluorinated polymers. Radical, disruptive new solutions are needed. Meanwhile, more reasonable, more selective use of these compounds appears indispensable in order to reduce exposure while preserving their societal benefits and without penalizing developing countries. Progress in the risk management of per- and polyfluorinated substances is, however, impeded by considerable knowledge and information gaps, and will demand sustained multidisciplinary efforts. [ABSTRACT FROM AUTHOR]

Abstract: This overview covers recent literature on fluorinated amphiphiles and self-assemblies of biomedical interest. It includes 1) “standard” perfluoroalkylated surfactants, 2) (perfluoroalkyl)alkyl diblock amphiphiles, 3) amphiphilic biomimetics bearing multiple CF3 groups, and 4) the environmental issues raised by perfluorooctanoic acid, perfluorooctane sulfonate and related compounds. [Copyright &y& Elsevier]

Fluorocarbon gases have been key to the recent development of several commercial injectable microbubble products that serve as contrast agents for ultrasound imaging. Microbubble-specific imaging is obtained by using harmonic and pulse inversion techniques. Controlled bubble destruction and monitoring of their re-entry into tissues provide unique tools for blood flow and tissue perfusion studies. Contrast echosonography allows assessment of structural and functional cardiovascular abnormalities and solid organ lesions, including tumors. New microbubble agents that target specific tissues, allowing molecular imaging of thrombi, atherosclerotic plaques, inflammation area and angiogenesis related to tumor growth, are being investigated. Microbubbles also have potential as therapeutic tools, and as targeted and ultrasound-triggered drug and gene delivery systems. [Copyright &y& Elsevier]

Fluorinated components useful for organizing space at the molecular, nanometer and micrometer scales include perfluorocarbons, perfluoroalkylated surfactants and perfluoroalkyl/alkyl diblock amphiphiles. Perfluoroalkyl moieties, being lipophobic as well as highly hydrophobic, add a new dimension to the hydrophobic segregation effect. Fluorinated amphiphiles, therefore, have an enhanced tendency to self-assemble in various media into stable, highly organized fluorinated colloids, thus generating organized nanometer-size fluorous phases, i.e. fluorous domains with at least one dimension in the nanometer range. Such fluorous nanophases are found in variously shaped micelles, Langmuir films, and bilayer membranes, as in vesicles, tubules and other molecular self-assemblies. Micron-size fluorous phases are present in diverse colloids that comprise liquid, solid and gaseous perfluorocarbons, such as in emulsions, microemulsions, multiple emulsions, microbubbles, gels and dispersions. Continuous or dispersed fluorous, hydrocarbonous and aqueous phases can be present simultaneously. Research on colloidal systems involving highly fluorinated components and destined for biomedical uses (injectable O2 carriers, contrast agents, drug delivery systems and other devices) has generated a wealth of data. These data are analyzed here from the perspective of the formation, structure and behavior of fluorous nano- and microphases in colloidal systems. Fluorocarbons and fluorinated amphiphiles allow the formulation of an array of multicomponent, multiphase compartmented colloidal systems and nano-objects with various architectures, differential solubility and diffusibility characteristics, and other properties, and exclusion zones that have potential as microreservoirs, microreactors and templates useful for reaction, morphology and functionality control well beyond their initial biomedical purpose. [Copyright &y& Elsevier]

A phase III clinical study of a perfluorooctyl bromide emulsion demonstrated reduction and avoidance of donor blood transfusion in surgery. Novel fluorocarbon-in-water emulsions are being investigated, including emulsions highly stabilized by fluorocarbon–hydrocarbon diblocks and targeted emulsions for molecular imaging, diagnosis and drug delivery. Reverse water-in-fluorocarbon emulsions and microemulsions that have potential for pulmonary drug delivery are also being studied. Microemulsions with highly fluorinated components are being actively investigated, with applications in polymerization technology and as research tools. [Copyright &y& Elsevier]