Advertisement

Microchimica Acta

, 187:150 | Cite as

Carbon dots with pH-responsive fluorescence: a review on synthesis and cell biological applications

  • Hamide Ehtesabi
  • Zahra Hallaji
  • Shima Najafi Nobar
  • Zeinab BagheriEmail author
Review Article
  • 105 Downloads

Abstract

This review summarizes state of the art synthesis and applications of carbon dots (CDs) with pH-responsive fluorescence. Following an introduction, the first section covers methods for the preparation of pH-responsive CDs, with subsections on general methods for preparing CDs (by hydrothermal, solvothermal, electrochemical, microwave, laser ablation, pyrolysis or chemical oxidation polymerization methods), and on precursors for synthesis. This is followed by a section on the mechanisms of pH-responsivity (by creating new functional groups, change of energy levels, protonation and deprotonation, aggregation, or by introduction shells). Several Tables are presented that give an overview of the wealth of methods and materials. A final section covers applications of carbon dots (CDs) with pH-responsive fluorescence for sensing, drug delivery, and imaging. The conclusion summarizes the current status, addresses challenges, and gives an outlook on potential future trends.

Graphical abstract

The synthesis and biological applications of carbon dots(CDs) with pH-responsive fluorescence are summarized. Precursors and methods for preparation of pH-responsive CDs, mechanisms of pH-responsivity, and biological applications of CDs with pH-responsive fluorescence for sensing, drug delivery, and imaging are discussed.

Keywords

Carbon dots pH-responsive fluorescence Hydrothermal synthesis pH-responsive mechanism pH sensing Drug delivery Imaging agent 

Notes

References

  1. 1.
    Han J, Burgess K (2009) Fluorescent indicators for intracellular pH. Chem Rev 110(5):2709–2728Google Scholar
  2. 2.
    Kurkdjian A, Guern J (1989) Intracellular pH: measurement and importance in cell activity. Annu Rev Plant Biol 40(1):271–303Google Scholar
  3. 3.
    Arandian A, Bagheri Z, Ehtesabi H, Najafi Nobar S, Aminoroaya N, Samimi A, Latifi H (2019) Optical imaging approaches to monitor static and dynamic cell-on-Chip platforms: a tutorial review. Small 15:1900737Google Scholar
  4. 4.
    Cohen JS, Motiei M, Carmi S, Shiperto D, Yefet O, Ringel I (2004) Determination of intracellular pH and compartmentation using diffusion-weighted NMR spectroscopy with pH-sensitive indicators. Magnetic Resonance in Medicine: An Official Journal of the International Society for Magnetic Resonance in Medicine 51(5):900–903Google Scholar
  5. 5.
    Wray S (1988) Smooth muscle intracellular pH: measurement, regulation, and function. Am J Phys Cell Phys 254(2):C213–C225Google Scholar
  6. 6.
    Izutsu K, Yamamoto H (1996) Response of an iridium oxide pH-sensor in nonaqueous solutions. Comparison with other pH-sensors. Anal Sci 12(6):905–909Google Scholar
  7. 7.
    Frant M (1995) How to measure pH in mixed and nonaqueous solutions. Today’s Chemist at Work 4:39Google Scholar
  8. 8.
    Ma B, Xu M, Zeng F, Huang L, Wu S (2011) Micelle nanoparticles for FRET-based ratiometric sensing of mercury ions in water, biological fluids and living cells. Nanotechnology 22(6):065501PubMedGoogle Scholar
  9. 9.
    Di W, Shirahata N, Zeng H, Sakka Y (2010) Fluorescent sensing of colloidal CePO4: Tb nanorods for rapid, ultrasensitive and selective detection of vitamin C. Nanotechnology 21(36):365501PubMedGoogle Scholar
  10. 10.
    Negi DP, Chanu TI (2008) Surface-modified CdS nanoparticles as a fluorescent probe for the selective detection of cysteine. Nanotechnology 19(46):465503PubMedGoogle Scholar
  11. 11.
    Kim HN, Ren WX, Kim JS, Yoon J (2012) Fluorescent and colorimetric sensors for detection of lead, cadmium, and mercury ions. Chem Soc Rev 41(8):3210–3244PubMedGoogle Scholar
  12. 12.
    Yu C, Zeng F, Luo M, Wu S (2012) A silica nanoparticle-based sensor for selective fluorescent detection of homocysteine via interaction differences between thiols and particle-surface-bound polymers. Nanotechnology 23(30):305503PubMedGoogle Scholar
  13. 13.
    Ma B, Wu S, Zeng F, Luo Y, Zhao J, Tong Z (2010) Nanosized diblock copolymer micelles as a scaffold for constructing a ratiometric fluorescent sensor for metal ion detection in aqueous media. Nanotechnology 21(19):195501PubMedGoogle Scholar
  14. 14.
    Wang J, Moore J, Laulhe S, Nantz M, Achilefu S, Kang KA (2012) Fluorophore–gold nanoparticle complex for sensitive optical biosensing and imaging. Nanotechnology 23(9):095501PubMedGoogle Scholar
  15. 15.
    Zhu H, Zhang W, Zhang K, Wang S (2012) Dual-emission of a fluorescent graphene oxide–quantum dot nanohybrid for sensitive and selective visual sensor applications based on ratiometric fluorescence. Nanotechnology 23(31):315502PubMedGoogle Scholar
  16. 16.
    Narayanan A, Varnavski O, Mongin O, Majoral J-P, Blanchard-Desce M, Goodson Iii T (2008) Detection of TNT using a sensitive two-photon organic dendrimer for remote sensing. Nanotechnology 19(11):115502Google Scholar
  17. 17.
    Stich MI, Fischer LH, Wolfbeis OS (2010) Multiple fluorescent chemical sensing and imaging. Chem Soc Rev 39(8):3102–3114PubMedGoogle Scholar
  18. 18.
    Zhu H, Fan J, Xu Q, Li H, Wang J, Gao P, Peng X (2012) Imaging of lysosomal pH changes with a fluorescent sensor containing a novel lysosome-locating group. Chem Commun 48(96):11766–11768Google Scholar
  19. 19.
    Schutting S, Borisov SM, Klimant I (2013) Diketo-pyrrolo-pyrrole dyes as new colorimetric and fluorescent pH indicators for optical carbon dioxide sensors. Anal Chem 85(6):3271–3279PubMedGoogle Scholar
  20. 20.
    Pina-Luis G, Martínez-Quiroz M, Ochoa-Teran A, Santacruz-Ortega H, Mendez-Valenzuela E (2013) New dual emission fluorescent sensor for pH and Pb (II) based on bis (napfthalimide) derivative. J Lumin 134:729–738Google Scholar
  21. 21.
    Fan L, Fu Y-J, Liu Q-L, Lu D-T, Dong C, Shuang S-M (2012) Novel far-visible and near-infrared pH probes based on styrylcyanine for imaging intracellular pH in live cells. Chem Commun 48(91):11202–11204Google Scholar
  22. 22.
    Burgstaller S, Bischof H, Gensch T, Stryeck S, Gottschalk B, Ramadani-Muja J, Eroglu E, Rost R, Balfanz S, Baumann A (2019) pH-lemon, a fluorescent protein-based pH reporter for acidic compartments. ACS sensors 4(4):883–891PubMedPubMedCentralGoogle Scholar
  23. 23.
    Miesenböck G, De Angelis DA, Rothman JE (1998) Visualizing secretion and synaptic transmission with pH-sensitive green fluorescent proteins. Nature 394(6689):192PubMedGoogle Scholar
  24. 24.
    Shen Y, Rosendale M, Campbell RE, Perrais D (2014) pHuji, a pH-sensitive red fluorescent protein for imaging of exo-and endocytosis. J Cell Biol 207(3):419–432PubMedPubMedCentralGoogle Scholar
  25. 25.
    Esposito A, Gralle M, Dani MAC, Lange D, Wouters FS (2008) pHlameleons: a family of FRET-based protein sensors for quantitative pH imaging. Biochemistry 47(49):13115–13126PubMedGoogle Scholar
  26. 26.
    Kremers G-J, Goedhart J, van Munster EB, Gadella TW (2006) Cyan and yellow super fluorescent proteins with improved brightness, protein folding, and FRET Förster radius. Biochemistry 45(21):6570–6580PubMedGoogle Scholar
  27. 27.
    Shangguan J, He D, He X, Wang K, Xu F, Liu J, Tang J, Yang X, Huang J (2016) Label-free carbon-dots-based ratiometric fluorescence pH nanoprobes for intracellular pH sensing. Anal Chem 88(15):7837–7843PubMedGoogle Scholar
  28. 28.
    Du F, Ming Y, Zeng F, Yu C, Wu S (2013) A low cytotoxic and ratiometric fluorescent nanosensor based on carbon-dots for intracellular pH sensing and mapping. Nanotechnology 24(36):365101PubMedGoogle Scholar
  29. 29.
    Wang H, Di J, Sun Y, Fu J, Wei Z, Matsui H, Alonso A, Zhou S (2015) Biocompatible PEG-chitosan@ carbon dots hybrid nanogels for two-photon fluorescence imaging, near-infrared light/pH dual-responsive drug carrier, and synergistic therapy. Adv Funct Mater 25(34):5537–5547Google Scholar
  30. 30.
    Kong B, Zhu A, Ding C, Zhao X, Li B, Tian Y (2012) Carbon dot-based inorganic–organic nanosystem for two-photon imaging and biosensing of pH variation in living cells and tissues. Adv Mater 24(43):5844–5848PubMedGoogle Scholar
  31. 31.
    Shi W, Li X, Ma H (2012) A tunable ratiometric pH sensor based on carbon nanodots for the quantitative measurement of the intracellular pH of whole cells. Angew Chem Int Ed 51(26):6432–6435Google Scholar
  32. 32.
    Chang MMF, Ginjom IR, Ngu-Schwemlein M, Ng SM (2016) Synthesis of yellow fluorescent carbon dots and their application to the determination of chromium (III) with selectivity improved by pH tuning. Microchim Acta 183(6):1899–1907Google Scholar
  33. 33.
    Kalaiyarasan G, Joseph J (2017) Determination of vitamin B12 via pH-dependent quenching of the fluorescence of nitrogen doped carbon quantum dots. Microchim Acta 184(10):3883–3891Google Scholar
  34. 34.
    Ehtesabi H, Ahadian M, Taghikhani V (2014) Investigation of diffusion and deposition of TiO2 nanoparticles in sandstone rocks for EOR application. In: 76th EAGE Conference and Exhibition 2014Google Scholar
  35. 35.
    Ehtesabi H, Bagheri Z, Avini MY (2019) Application of three-dimensional Graphene hydrogels for removal of Ofloxacin from aqueous solutions. Environmental nanotechnology, monitoring & management:100274Google Scholar
  36. 36.
    Ehtesabi H, Bagheri Z, Eskandari F, Ahadian MM (2018) Molecular interaction between three-dimensional graphene aerogel and enzyme solution: effect on enzyme structure and function. J Mol Liq 265:565–571Google Scholar
  37. 37.
    Pirsaheb M, Mohammadi S, Salimi A, Payandeh M (2019) Functionalized fluorescent carbon nanostructures for targeted imaging of cancer cells: a review. Microchim Acta 186(4):231Google Scholar
  38. 38.
    Hamide Ehtesabi, Shabnam Roshani, Zeinab Bagheri, Mohammad Yaghoubi-Avini, (2019) Carbon dots—Sodium alginate hydrogel: A novel tetracycline fluorescent sensor and adsorber. Journal of Environmental Chemical Engineering 7(5):103419Google Scholar
  39. 39.
    Tomasulo M, Yildiz I, Raymo FM (2006) pH-sensitive quantum dots. J Phys Chem B 110(9):3853–3855PubMedGoogle Scholar
  40. 40.
    Hardman R (2005) A toxicologic review of quantum dots: toxicity depends on physicochemical and environmental factors. Environ Health Perspect 114(2):165–172PubMedCentralGoogle Scholar
  41. 41.
    Chen N, He Y, Su Y, Li X, Huang Q, Wang H, Zhang X, Tai R, Fan C (2012) The cytotoxicity of cadmium-based quantum dots. Biomaterials 33(5):1238–1244PubMedGoogle Scholar
  42. 42.
    Bagheri Z, Ehtesabi H, Rahmandoust M, Ahadian MM, Hallaji Z, Eskandari F, Jokar E (2017) New insight into the concept of carbonization degree in synthesis of carbon dots to achieve facile smartphone based sensing platform. Sci Rep 7(1):11013PubMedPubMedCentralGoogle Scholar
  43. 43.
    Barati A, Shamsipur M, Abdollahi H (2016) Carbon dots with strong excitation-dependent fluorescence changes towards pH. Application as nanosensors for a broad range of pH Analytica chimica acta 931:25–33PubMedGoogle Scholar
  44. 44.
    Liu W, Li C, Sun X, Pan W, Wang J (2017) Carbon-dot-based ratiometric fluorescent pH sensor for the detections of very weak acids assisted by auxiliary reagents that contribute to the release of protons. Sensors Actuators B Chem 244:441–449Google Scholar
  45. 45.
    Qu S, Chen H, Zheng X, Cao J, Liu X (2013) Ratiometric fluorescent nanosensor based on water soluble carbon nanodots with multiple sensing capacities. Nanoscale 5(12):5514–5518PubMedGoogle Scholar
  46. 46.
    Xu H, Yan L, Nguyen V, Yu Y, Xu Y (2017) One-step synthesis of nitrogen-doped carbon nanodots for ratiometric pH sensing by femtosecond laser ablation method. Appl Surf Sci 414:238–243Google Scholar
  47. 47.
    Sun Y, Wang X, Wang C, Tong D, Wu Q, Jiang K, Jiang Y, Wang C, Yang M (2018) Red emitting and highly stable carbon dots with dual response to pH values and ferric ions. Microchim Acta 185(1):83Google Scholar
  48. 48.
    Dutta Choudhury S, Chethodil JM, Gharat PM, Pal H (2017) pH-elicited luminescence functionalities of carbon dots: mechanistic insights. The journal of physical chemistry letters 8(7):1389–1395PubMedGoogle Scholar
  49. 49.
    Liu Y, Zhou Q (2017) Sensitive pH probe developed with water-soluble fluorescent carbon dots from chocolate by one-step hydrothermal method. Int J Environ Anal Chem 97(12):1119–1131Google Scholar
  50. 50.
    Jin X, Sun X, Chen G, Ding L, Li Y, Liu Z, Wang Z, Pan W, Hu C, Wang J (2015) pH-sensitive carbon dots for the visualization of regulation of intracellular pH inside living pathogenic fungal cells. Carbon 81:388–395Google Scholar
  51. 51.
    Doroodmand MM, Askari M (2017) Synthesis of a novel nitrogen-doped carbon dot by microwave-assisted carbonization method and its applications as selective probes for optical ph (acidity) sensing in aqueous/nonaqueous media, determination of nitrate/nitrite, and optical recognition of nox gas. Anal Chim Acta 968:74–84PubMedGoogle Scholar
  52. 52.
    Yang M, Li B, Zhong K, Lu Y (2018) Photoluminescence properties of N-doped carbon dots prepared in different solvents and applications in pH sensing. J Mater Sci 53(4):2424–2433Google Scholar
  53. 53.
    Song Z, Quan F, Xu Y, Liu M, Cui L, Liu J (2016) Multifunctional N, S co-doped carbon quantum dots with pH-and thermo-dependent switchable fluorescent properties and highly selective detection of glutathione. Carbon 104:169–178Google Scholar
  54. 54.
    Ding Y-Y, Gong X-J, Liu Y, Lu W-J, Gao Y-F, Xian M, Shuang S-M, Dong C (2018) Facile preparation of bright orange fluorescent carbon dots and the constructed biosensing platform for the detection of pH in living cells. Talanta 189:8–15PubMedGoogle Scholar
  55. 55.
    He Y, Li Z, Jia Q, Shi B, Zhang H, Wei L, Yu M (2017) Ratiometric fluorescent detection of acidic pH in lysosome with carbon nanodots. Chin Chem Lett 28(10):1969–1974Google Scholar
  56. 56.
    Wang C, Xu Z, Zhang C (2015) Polyethyleneimine-functionalized fluorescent carbon dots: water stability, pH sensing, and cellular imaging. ChemNanoMat 1(2):122–127Google Scholar
  57. 57.
    Fan Z, Zhou S, Garcia C, Fan L, Zhou J (2017) pH-responsive fluorescent graphene quantum dots for fluorescence-guided cancer surgery and diagnosis. Nanoscale 9(15):4928–4933PubMedPubMedCentralGoogle Scholar
  58. 58.
    Zhang C, Cui Y, Song L, Liu X, Hu Z (2016) Microwave assisted one-pot synthesis of graphene quantum dots as highly sensitive fluorescent probes for detection of iron ions and pH value. Talanta 150:54–60PubMedGoogle Scholar
  59. 59.
    Yuan F, Ding L, Li Y, Li X, Fan L, Zhou S, Fang D, Yang S (2015) Multicolor fluorescent graphene quantum dots colorimetrically responsive to all-pH and a wide temperature range. Nanoscale 7(27):11727–11733PubMedGoogle Scholar
  60. 60.
    Sarkar N, Sahoo G, Das R, Prusty G, Swain SK (2017) Carbon quantum dot tailored calcium alginate hydrogel for pH responsive controlled delivery of vancomycin. Eur J Pharm Sci 109:359–371PubMedGoogle Scholar
  61. 61.
    Wu ZL, Gao MX, Wang TT, Wan XY, Zheng LL, Huang CZ (2014) A general quantitative pH sensor developed with dicyandiamide N-doped high quantum yield graphene quantum dots. Nanoscale 6(7):3868–3874PubMedGoogle Scholar
  62. 62.
    Shirani MP, Rezaei B, Khayamian T, Dinari M, Shamili FH, Ramezani M, Alibolandi M (2018) Ingenious pH-sensitive etoposide loaded folic acid decorated mesoporous silica-carbon dot with carboxymethyl-βcyclodextrin gatekeeper for targeted drug delivery and imaging. Mater Sci Eng C 92:892–901Google Scholar
  63. 63.
    Jiao J, Liu C, Li X, Liu J, Di D, Zhang Y, Zhao Q, Wang S (2016) Fluorescent carbon dot modified mesoporous silica nanocarriers for redox-responsive controlled drug delivery and bioimaging. J Colloid Interface Sci 483:343–352PubMedGoogle Scholar
  64. 64.
    Sawant V, Bamane S, Kanase D, Patil S, Ghosh J (2016) Encapsulation of curcumin over carbon dot coated TiO 2 nanoparticles for pH sensitive enhancement of anticancer and anti-psoriatic potential. RSC Adv 6(71):66745–66755Google Scholar
  65. 65.
    Mao Y, Bao Y, Yan L, Li G, Li F, Han D, Zhang X, Niu L (2013) pH-switched luminescence and sensing properties of a carbon dot–polyaniline composite. RSC Adv 3(16):5475–5482Google Scholar
  66. 66.
    Ahmad K, Gogoi SK, Begum R, Sk MP, Paul A, Chattopadhyay A (2017) An interactive quantum dot and carbon dot conjugate for pH-sensitive and ratiometric Cu2+ sensing. ChemPhysChem 18(6):610–616PubMedGoogle Scholar
  67. 67.
    Wang L, Chen Y (2018) Lanthanide doped carbon dots as a fluorescence chromaticity-based pH probe. Microchim Acta 185(10):489Google Scholar
  68. 68.
    Tuerhong M, Yang X, Xue-Bo Y (2017) Review on carbon dots and their applications. Chin J Anal Chem 45(1):139–150Google Scholar
  69. 69.
    Yao B, Huang H, Liu Y, Kang Z (2019) Carbon dots: a small conundrum. Trends in Chemistry 1:235–246Google Scholar
  70. 70.
    Sharma V, Tiwari P, Mobin SM (2017) Sustainable carbon-dots: recent advances in green carbon dots for sensing and bioimaging. J Mater Chem B 5(45):8904–8924Google Scholar
  71. 71.
    Shi B, Zhang L, Lan C, Zhao J, Su Y, Zhao S (2015) One-pot green synthesis of oxygen-rich nitrogen-doped graphene quantum dots and their potential application in pH-sensitive photoluminescence and detection of mercury (II) ions. Talanta 142:131–139PubMedGoogle Scholar
  72. 72.
    Li B, Ma H, Zhang B, Qian J, Cao T, Feng H, Li W, Dong Y, Qin W (2019) Dually emitting carbon dots as fluorescent probes for ratiometric fluorescent sensing of pH values, mercury (II), chloride and Cr (VI) via different mechanisms. Microchim Acta 186(6):341Google Scholar
  73. 73.
    Wang Q, Yang H, Zhang Q, Ge H, Zhang S, Wang Z, Ji X (2019) Strong acid-assisted preparation of green-emissive carbon dots for fluorometric imaging of pH variation in living cells. Microchim Acta 186(7):468Google Scholar
  74. 74.
    Shi L, Li Y, Li X, Zhao B, Wen X, Zhang G, Dong C, Shuang S (2016) Controllable synthesis of green and blue fluorescent carbon nanodots for pH and Cu2+ sensing in living cells. Biosens Bioelectron 77:598–602PubMedGoogle Scholar
  75. 75.
    Zetan Fan, Shixin Zhou, Cesar Garcia, Louzhen Fan, Jiangbing Zhou, (2017) pH-Responsive fluorescent graphene quantum dots for fluorescence-guided cancer surgery and diagnosis. Nanoscale 9(15):4928-4933Google Scholar
  76. 76.
    Safavi A, Ahmadi R, Mohammadpour Z, Zhou J (2016) Fluorescent pH nanosensor based on carbon nanodots for monitoring minor intracellular pH changes. RSC Adv 6(106):104657–104664Google Scholar
  77. 77.
    Li M, Chen T, Gooding JJ, Liu J (2019) Review of carbon and graphene quantum dots for sensing. ACS sensors 4(7):1732–1748PubMedGoogle Scholar
  78. 79.
    Basu N, Mandal D (2019) Time-resolved photoluminescence of pH-sensitive carbon dots. Carbon 144:500–508Google Scholar
  79. 78.
    Liu X, Yang C, Zheng B, Dai J, Yan L, Zhuang Z, Du J, Guo Y, Xiao D (2018) Green anhydrous synthesis of hydrophilic carbon dots on large-scale and their application for broad fluorescent pH sensing. Sensors Actuators B Chem 255:572–579Google Scholar
  80. 81.
    Kochmann S, Hirsch T, Wolfbeis OS (2012) The pH dependence of the total fluorescence of graphite oxide. J Fluoresc 22(3):849–855PubMedGoogle Scholar
  81. 80.
    Chen J-L, Yan X-P (2011) Ionic strength and pH reversible response of visible and near-infrared fluorescence of graphene oxide nanosheets for monitoring the extracellular pH. Chem Commun 47(11):3135–3137Google Scholar
  82. 82.
    Minati L, Speranza G, Bernagozzi I, Torrengo S, Toniutti L, Rossi B, Ferrari M, Chiasera A (2010) Investigation on the electronic and optical properties of short oxidized multiwalled carbon nanotubes. J Phys Chem C 114(25):11068–11073Google Scholar
  83. 83.
    Strano MS, Huffman CB, Moore VC, O’Connell MJ, Haroz EH, Hubbard J, Miller M, Rialon K, Kittrell C, Ramesh S, Hauge RH, Smalley RE (2003) J. Phys. Chem. B 107:6979Google Scholar
  84. 84.
    Galande C, Mohite AD, Naumov AV, Gao W, Ci L, Ajayan A, Gao H, Srivastava A, Weisman RB, Ajayan PM (2011) Quasi-molecular fluorescence from graphene oxide. Sci Rep 1:85PubMedPubMedCentralGoogle Scholar
  85. 85.
    Jin SH, Kim DH, Jun GH, Hong SH, Jeon S (2013) Tuning the photoluminescence of graphene quantum dots through the charge transfer effect of functional groups. ACS Nano 7(2):1239–1245PubMedGoogle Scholar
  86. 86.
    Yao C, Xu Y, Xia Z (2018) A carbon dot-encapsulated UiO-type metal organic framework as a multifunctional fluorescent sensor for temperature, metal ion and pH detection. J Mater Chem C 6(16):4396–4399Google Scholar
  87. 87.
    Wang Y, Lu L, Peng H, Xu J, Wang F, Qi R, Xu Z, Zhang W (2016) Multi-doped carbon dots with ratiometric pH sensing properties for monitoring enzyme catalytic reactions. Chem Commun 52(59):9247–9250Google Scholar
  88. 88.
    Khan S, Gupta A, Verma NC, Nandi CK (2015) Time-resolved emission reveals ensemble of emissive states as the origin of multicolor fluorescence in carbon dots. Nano Lett 15(12):8300–8305PubMedGoogle Scholar
  89. 89.
    Hao Y, Gan Z, Zhu X, Li T, Wu X, Chu PK (2015) Emission from trions in carbon quantum dots. J Phys Chem C 119(6):2956–2962Google Scholar
  90. 90.
    Hu Y, Yang J, Tian J, Jia L, Yu J-S (2014) Waste frying oil as a precursor for one-step synthesis of sulfur-doped carbon dots with pH-sensitive photoluminescence. Carbon 77:775–782Google Scholar
  91. 91.
    Park CH, Yang H, Lee J, Cho H-H, Kim D, Lee DC, Kim BJ (2015) Multicolor emitting block copolymer-integrated graphene quantum dots for colorimetric, simultaneous sensing of temperature, pH, and metal ions. Chem Mater 27(15):5288–5294Google Scholar
  92. 92.
    Kong W, Wu H, Ye Z, Li R, Xu T, Zhang B (2014) Optical properties of pH-sensitive carbon-dots with different modifications. J Lumin 148:238–242Google Scholar
  93. 93.
    Zheng C, An X, Gong J (2015) Novel pH sensitive N-doped carbon dots with both long fluorescence lifetime and high quantum yield. RSC Adv 5(41):32319–32322Google Scholar
  94. 94.
    Omidi M, Yadegari A, Tayebi L (2017) Wound dressing application of pH-sensitive carbon dots/chitosan hydrogel. RSC Adv 7(18):10638–10649Google Scholar
  95. 95.
    Qian Z, Ma J, Shan X, Feng H, Shao L, Chen J (2014) Highly luminescent N-doped carbon quantum dots as an effective multifunctional fluorescence sensing platform. Chem Eur J 20(8):2254–2263PubMedGoogle Scholar
  96. 96.
    Nie H, Li M, Li Q, Liang S, Tan Y, Sheng L, Shi W, Zhang SX-A (2014) Carbon dots with continuously tunable full-color emission and their application in ratiometric pH sensing. Chem Mater 26(10):3104–3112Google Scholar
  97. 97.
    Shen C, Sun Y, Wang J, Lu Y (2014) Facile route to highly photoluminescent carbon nanodots for ion detection, pH sensors and bioimaging. Nanoscale 6(15):9139–9147PubMedGoogle Scholar
  98. 98.
    Chowdhuri AR, Singh T, Ghosh SK, Sahu SK (2016) Carbon dots embedded magnetic nanoparticles@ chitosan@ metal organic framework as a nanoprobe for pH sensitive targeted anticancer drug delivery. ACS Appl Mater Interfaces 8(26):16573–16583PubMedGoogle Scholar
  99. 99.
    Qiu J, Zhang R, Li J, Sang Y, Tang W, Gil PR, Liu H (2015) Fluorescent graphene quantum dots as traceable, pH-sensitive drug delivery systems. Int J Nanomedicine 10:6709PubMedPubMedCentralGoogle Scholar
  100. 100.
    Choi CA, Lee JE, Mazrad ZAI, Kim YK, In I, Jeong JH, Park SY (2018) Dual-responsive carbon dot for pH/redox-triggered fluorescence imaging with controllable Photothermal ablation therapy of Cancer. ChemMedChem 13(14):1459–1468PubMedGoogle Scholar
  101. 101.
    Feng T, Ai X, Ong H, Zhao Y (2016) Dual-responsive carbon dots for tumor extracellular microenvironment triggered targeting and enhanced anticancer drug delivery. ACS Appl Mater Interfaces 8(29):18732–18740PubMedGoogle Scholar
  102. 102.
    Wang H, Sun Y, Yi J, Fu J, Di J, del Carmen AA, Zhou S (2015) Fluorescent porous carbon nanocapsules for two-photon imaging, NIR/pH dual-responsive drug carrier, and photothermal therapy. Biomaterials 53:117–126PubMedGoogle Scholar
  103. 103.
    Zuo P, Lu X, Sun Z, Guo Y, He H (2016) A review on syntheses, properties, characterization and bioanalytical applications of fluorescent carbon dots. Microchim Acta 183(2):519–542Google Scholar
  104. 104.
    Bagheri Z, Ehtesabi H, Hallaji Z, Latifi H, Behroodi E (2018) Investigation the cytotoxicity and photo-induced toxicity of carbon dot on yeast cell. Ecotoxicol Environ Saf 161:245–250PubMedGoogle Scholar

Copyright information

© Springer-Verlag GmbH Austria, part of Springer Nature 2020

Authors and Affiliations

  1. 1.Faculty of Life Sciences and BiotechnologyShahid Beheshti University G.CTehranIran
  2. 2.Faculty of Biological SciencesTarbiat Modares UniversityTehranIran
  3. 3.Faculty of Mechanical EngineeringK. N. Toosi University of TechnologyTehranIran

Personalised recommendations