simple organic structures , organic / inorganic polymers , and other substrates have been made , all of which have at least one pyrrolidone moiety present , and found to exhibit low toxicity , low complement activation features and may be used to reduce protein interactions with drug conjugates while enhancing in vivo residency times for these conjugates when used as an injectable composition ; thus these compounds can be used as substitutes for peg in pegaylation . surprisingly , these compounds also exhibit unique intrinsic fluorescence or non - traditional fluorescence properties that currently cannot be explained by traditional photochemistry and fluorescence paradigms are described . these compounds have a variety of applications such as in cellular imaging , gene transfection , bio - diagnostics , biosensing , fluorescence directed surgical resections , drug delivery , forensics , environmental diagnostics , mineral / gemstone characterization , counterfeit goods detection , tracer studies related to liquid / water flow , oil field enhancements and diagnostics , prevention of photo - bleaching , and led display enhancements and others .