Star-dots fluorescent nanoparticles for flow cytometry and biomedical imaging

Fluorescent nanoparticlesFNPare becoming increasingly popular in biomedical imaging and taggingCompared to molecule based fluorophoresFNP are typically brighter and more photostableThey can be functionalized with more than one tagging moleculeused for the tagging and tracing of specific moleculescellstissuesBrighter fluorescence facilitates more sensitive labelingand in many casesa lower limit of detectionIn flow cytometry it may open new limits of detecting low number of receptors on cells and exosomesNanoScience Solutions LLCNSSis developing exceptionally bright nanoporous silica FNPsuggested commercial nameStar dotsnanoporous silica FNPin which fluorescent dye molecules are physically encapsulated in a specific nano environment of cylindrical nanochannelsTo the best of our knowledgeStar dots are the brightest currently available FNPvetted by multiple PI s publications in high level journals and numerous citationsStar dots exhibit good colloidal stabilitymonths yearsno dye leakageno fast aggregation and negligible spectral change in different mediano blinkinglow photobleaching compared to freenon encapsulateddyeand the absence of non fluorescent particlesDue to close proximity of encapsulated dye molecules to each otherwhich allows the attainment of quantum coupling between dye moleculesdevelopment of particles with fluorescent spectra of almost arbitrary complexity is feasibleincluding multiple spectra that can be excited with the same wavelengthSuch particles are of big interest to various multiplexed assaysin particularto multi spectral flow cytometryPhysical encapsulationversus the currently used standard chemical bondingof existing fluorescent dyes allows the use of a large number of commercially available dyes with no modificationincluding hard to modify near infrared dyesHoweverdespite these advantagesStar dots cannot be used for biomedical applications as of yetThe critical missing part is functionalization of Star dots with tagging moleculesStandard ways of silica functionalization kill fluorescence of Star dotsThis STTR Phase I project willaddress this critical problem andtest the feasibility of using Star dots for multiplexing applicationsSpecificallywe proposeDemonstrate that feasibility of functionalizing Star dots with functionaltaggingmolecules while preserving Star dot high fluorescent brightnessCoating Star dots with protective moleculeslikepolyethylene glycolto decrease nonspecific interactions will also be exploredTest Star dots for multiplexing applicationsOur preliminary data demonstrate the development of multiplefluorescent spectra excited with one wavelengthbut only when using micron size particlesScaling downthe size of these particles to nanoscale is highly non trivial and always associated with high riskThe academic partner will deal with all characterizations of Star dotsThe small business partner has the experience of development of various Star dotsThe successful completion of Phase I will substantially decrease risk associated with the ambitious goal of introducing Star dots into the biomedical arenaCreation of newbrightstablenon toxic fluorescent markerswhichin many respectsare superior to the existing fluorescent nanoparticleswill provide a new tool to the biomedical community and facilitate research involving detectiontransportflow cytometry and the imaging of biochemical events within living cellstissuesIt will lay the groundwork for the development of commercial prototype productsPhase IIOne of the expected specific goals of Phase II will be the development of Star dots for flow cytometry together with our partnerssuch as Beckman Coulterone of the leaders in flow cytometrysee their letter of interestThe proposed ultrabright fluorescent silica nanoparticles will expand the horizons of biomedical research and diagnosticsimaging and sensing in terms of depth of tissue imagingdetection speedsensitivityin particular in flow cytometryin which it will allow single cell and exosome studiesIt is expected that Star dots having large number of different spectra will enhance multiplexing capabilityrequire smaller volume samplesadvance and accelerate novel vaccine and adjuvant discovery for HIVmalariatuberculosisand emerging infectious disease threats