RESEARCH ARTICLE Fluorescence‐based logic gate for sensing of Ca 2+ and F - ions using PVP crowned chrysene nanoparticles in aqueous medium Prasad G. Mahajan | G.B. Kolekar | Shivajirao R. Patil Fluorescence Spectroscopy Laboratory, Department of Chemistry, Shivaji University Kolhapur, Maharashtra, India Correspondence Shivajirao R. Patil, Fluorescence Spectroscopy Laboratory, Department of Chemistry, Shivaji University Kolhapur, Maharashtra 416004, India. Email: srp_fsl@rediffmail.com Funding information University Grants Commission (UGC), New Delhi, India; Department of Science and Technology (DST), New Delhi, India Abstract Polyvinyl pyrrolidone (PVP) crowned chrysene nanoparticles (CHYNPs) were prepared by using a reprecipitation method. Dynamic light scattering (DLS) and scanning electron microscope (SEM) studies indicate that the monodispersed spherical nanoparticles bear a negative charge on their surfaces. The bathochromic spectral shift in the UV–visible and fluorescence spectrum of CHYNPs from chrysene (CHY) in acetone solution supports the J‐ type aggregation of nanoparticles. The aggregation‐induced enhanced emission of CHYNPs at 486 and 522 nm decreases by increasing the concentration of the Ca 2+ ion solution. It can display an ON–OFF type fluorescence response with high selectivity towards Ca 2+ ions aqueous medium. Furthermore, the in situ generated PVP–CHYNPs–Ca 2+ ensemble could recover the quenched fluorescence upon the addition of fluoride anions resulting in an OFF–ON type sensor. The present method has a correlation coefficient R 2 = 0.988 with a detection limit of 1.22 μg/mL for Ca 2+ in the aqueous medium. The fluorescence changes of PVP crowned CHYNPs upon the addition of Ca 2+ and F - can be utilized as an INHIBIT logic gate at the molecular level, using Ca 2+ and F - chemical inputs and the fluorescence intensity signal as output. KEYWORDS Ca 2+ ion, chrysene nanoparticles, F - ion, logic gates, OFF–ON fluorescence sensing 1 | INTRODUCTION The development of fluorescence‐based nanosensor for detection of cations and anions has attracted great research interest due to the important role played by ions in the wide range of environmental, clin- ical and biological systems. [1–5] To date, several reports are available that describe the detection of metal ions at trace levels using conven- tional analytical methods such as inductively coupled plasma atomic emission/mass spectroscopy (ICP‐AES/ICP‐MS), atomic absorption spectrometry (AAS), electrochemical methods, surface plasmon reso- nance detectors, quantum‐dot‐based assays. [6–11] These methods are fails to produce selectivity with high sensitivity, a tedious sample preparation method, are time consuming, demand skilled operatives and have a need for highly sophisticated/expensive instrumentation. Besides these methods, detection of cations and anions by a fluores- cent readout has attracted great attention in light of the advantages of fluorescence sensing, including easy operation, selectivity, high sensitivity, simplicity, high degree of specificity and low detection limit. Fluorescent organic nanoparticles (FONs)‐based sensors have become an increasing growing research area in the field of quantitative analyt- ical chemistry due to their sensitivity and selective behavior towards a particular analyte. Recently, FONs have been reported for the selective and sensitive detection of toxic and essential metal ions from aqueous media. [12–16] Several methods are available for the preparation of FONs viz. microemulsion, laser ablation, reprecipitation and ultrasonication. [17–20] However amongst these methods, the reprecipitation method is widely preferred due to its advantages over other methods such as simple and easy handling, cost–effectiveness and much eco‐friendly characteristics. [20] Additives in the form of ions, low‐molecular‐weight molecules such as surfactants, and neutral or charged polymers (polyelectrolytes) can be used sometimes in the preparation of FONs to stabilize and control the growth of particle formation process desirably. The use of ionic surfactant for the Abbreviations: AAS, atomic absorption spectrometry; AIEE, aggregation induced enhanced emission; CHY, chrysene; CHYNPS, chrysene nanoparticles; DLS, dynamic light scattering; DST, Department of Science and Technology; FON, fluorescent organic nanoparticles; PVP, polyvinyl pyrrolidone; SEM, scanning electron microscope; TCSPC, time correlated single photon counting; UGC, University Grants Commission. Received: 25 June 2016 Revised: 21 October 2016 Accepted: 3 November 2016 DOI 10.1002/bio.3262 Luminescence 2017; 1–10 Copyright © 2017 John Wiley & Sons, Ltd. wileyonlinelibrary.com/journal/bio 1