Skip to main content
SpringerLink
Log in

Hill-type pH probes

  • Trends
  • Published:
Analytical and Bioanalytical Chemistry Aims and scope Submit manuscript

Abstract

Sensitive detection of the minute and yet pathologically significant pH variation is important and in fact challenging for the conventional pH probes following the Henderson-Hasselbalch equation, i.e., HH-type probes. A paradigm shift to Hill-type pH probes is ongoing. Bestowed by their positive cooperative acid–base chemistry, their pH-responsive profile follows the Hill equation, which exhibits a narrower acid/base transition width than HH-type probes and warrants a higher detection sensitivity. A polymer-based Hill-type pH-responsive material was first developed. More recently, there emerged several distinct small-molecular approaches to achieve Hill-type pH-responsive profiles. They complement the polymer-based sensing materials in applications where membrane permeability is a concern. In this trends article, we rationalize the molecular origins of their positive cooperativity in pH sensing and highlight some interesting proof-of-concept applications. We also discussed future directions of this dynamic research area.

Graphical Abstract

This is a preview of subscription content, log in via an institution to check access.

Access this article

Log in via an institution

Price excludes VAT (USA)
Tax calculation will be finalised during checkout.

Instant access to the full article PDF.

Institutional subscriptions

Fig. 1

Copyright 2010 Springer Nature. C Two types of pH titration profiles with or without positive cooperativity in pH sensing. The classical Henderson-Hasselbalch type pH titration curve with two independent pKa’s (pKaHH1 and pKaHH2). Positive cooperativity in protonation leads to a Hill-type sigmoidal curve with only one independent pKa (pKaHill). Reprinted with permission from ref. [19]. Copyright 2018 American Chemical Society

Fig. 2

Copyright 2009 Royal Society of Chemistry. B Hill-type pH probes based on i-motifs with tunable transition midpoint via structural manipulation. Reprinted with permission from ref. [27]. Copyright 2011 John Wiley and Sons. C The design rationale of pH-activatable micellar nanoprobes and their pH titration curves. Reprinted with permission from ref. [33]. Copyright 2014 American Chemical Society. D Positive cooperative protonation of a metal–organic framework. Reprinted with permission from ref. [34]. Copyright 2021 American Chemical Society

Fig. 3

Copyright 2016, 2017 American Chemical Society. B Diagram of the equilibria of dianion (D), monoanion (M), and neutral (N) fluorescein congeners to achieve protonation cooperativity. X = C or Si for carbofluorescein and Si-fluorescein, respectively. C Chemical structure and pH sensing mechanism of NIR-OH-1 with its fluorescent emission spectra responding to pH changes. D Fluorescence images and relative fluorescence intensity of HeLa cells incubated with NIR-OH-1 and Mito-Tracker Green following CCCP stimulation. Intracellular pH calibration curve was obtained from images. Reprinted with permission from ref. [45]. Copyright 2021 John Wiley and Sons

Fig. 4

Copyright 2018 American Chemical Society. D Modulation of the pKa’s of PHX scaffold by tuning the substitution pattern of the dialkylamino group of the p-aminophenol moiety to yield PHN1-14. The structure-dependent pKa1 (pKa of the Hill-component) of PHN1-14. Reprinted with permission from ref. [48]. Copyright 2020 American Chemical Society. E The chemical structures of a focused library of Hill-type pH probes (Hilla-g). A correlation between the %Hill of Hilla-g and their mode of the Thorpe-Ingold dialkylations. Reprinted with permission from ref. [19]. Copyright 2021 American Chemical Society

Similar content being viewed by others

References

  1. Borisov SM, Wolfbeis OS. Optical biosensors. Chem Rev. 2008;108(2):423–61.

    CAS  PubMed  Google Scholar 

  2. Wang B, Anslyn EV. Chemosensors: principles, strategies, and applications. New Jersey: John Wiley & Sons; 2011.

  3. Knopf GK, Bassi AS. Smart biosensor technology. 2nd ed. Boca Raton: CRC press; 2018.

  4. Rong G, Corrie SR, Clark HA. In vivo biosensing: progress and perspectives. ACS sensors. 2017;2(3):327–38.

    CAS  PubMed  PubMed Central  Google Scholar 

  5. Germain ME, Knapp MJ. Optical explosives detection: from color changes to fluorescence turn-on. Chem Soc Rev. 2009;38(9):2543–55.

    CAS  PubMed  Google Scholar 

  6. Chen C, Tian R, Zeng Y, Chu C, Liu G. Activatable fluorescence probes for “turn-on” and ratiometric biosensing and bioimaging: from NIR-I to NIR-II. Bioconjug Chem. 2020;31(2):276–92.

    CAS  PubMed  Google Scholar 

  7. Haugland RP, Spence MTZ, Johnson ID, Basey A. The molecular probes handbook: a guide to fluorescent probes and labeling Technologies. Eugene: Life Technologies; 2010.

  8. Li J, Zhang M, Yang L, Han Y, Luo X, Qian X, et al. “Xanthene” is a premium bridging group for xanthenoid dyes. Chin Chem Lett. 2021;32(12):3865–9.

    CAS  Google Scholar 

  9. Shinkai S, Ikeda M, Sugasaki A, Takeuchi M. Positive allosteric systems designed on dynamic supramolecular scaffolds: toward switching and amplification of guest affinity and selectivity. Acc Chem Res. 2001;34(6):494–503.

    CAS  PubMed  Google Scholar 

  10. De Silva AP, Gunaratne HN, Gunnlaugsson T, Huxley AJ, McCoy CP, Rademacher JT, et al. Signaling recognition events with fluorescent sensors and switches. Chem Rev. 1997;97(5):1515–66.

    PubMed  Google Scholar 

  11. Hunter CA, Anderson HL. What is cooperativity? Angew Chem Int Ed. 2009;48(41):7488–99.

    CAS  Google Scholar 

  12. Levitzki A, Koshland DE Jr. Negative cooperativity in regulatory enzymes. Proc Natl Acad Sci USA. 1969;62(4):1121–8.

    CAS  PubMed  PubMed Central  Google Scholar 

  13. Ercolani G. Assessment of cooperativity in self-assembly. J Am Chem Soc. 2003;125(51):16097–103.

    CAS  PubMed  Google Scholar 

  14. Perutz MF, Wilkinson A, Paoli M, Dodson G. The stereochemical mechanism of the cooperative effects in hemoglobin revisited. Annu Rev Biophys Biomol Struct. 1998;27(1):1–34.

    CAS  PubMed  Google Scholar 

  15. Ng YK, Tajoddin NN, Scrosati PM, Konermann L. Mechanism of thermal protein aggregation: experiments and molecular dynamics simulations on the high-temperature behavior of myoglobin. J Phys Chem B. 2021;125(48):13099–110.

    CAS  PubMed  Google Scholar 

  16. Anslyn EV, Dougherty DA. Modern physical organic chemistry. Melville : University Science Books; 2006. p 219.

  17. Weiss JN. The Hill equation revisited: uses and misuses. FASEB J. 1997;11(11):835–41.

    CAS  PubMed  Google Scholar 

  18. Casey JR, Grinstein S, Orlowski J. Sensors and regulators of intracellular pH. Nat Rev Mol Cell Biol. 2010;11(1):50–61.

    CAS  PubMed  Google Scholar 

  19. Xiao Y, Huang Y, Zeng Z, Luo X, Qian X, Yang Y. Harnessing Thorpe-Ingold dialkylation to access high-Hill-percentage pH probes. J Org Chem. 2021;87(1):85–93.

    PubMed  Google Scholar 

  20. Roos A, Boron WF. Intracellular pH. Physiol Rev. 1981; 61(2):296–434

  21. Madshus IH. Regulation of intracellular pH in eukaryotic cells. Biochem J. 1988;250(1):1.

    CAS  PubMed  PubMed Central  Google Scholar 

  22. Kurkdjian A, Guern J. Intracellular pH: measurement and importance in cell activity. Ann Rev Plant Biol. 1989;40(1):271–303.

    CAS  Google Scholar 

  23. Vaughan-Jones RD, Spitzer KW, Swietach P. Intracellular pH regulation in heart. J Mol Cell Cardiol. 2009;46(3):318–31.

    CAS  PubMed  Google Scholar 

  24. Webb BA, Chimenti M, Jacobson MP, Barber DL. Dysregulated pH: a perfect storm for cancer progression. Nat Rev Cancer. 2011;11(9):671–7.

    CAS  PubMed  Google Scholar 

  25. Po HN, Senozan N. The Henderson-Hasselbalch equation: its history and limitations. J Chem Educ. 2001;78(11):1499.

    CAS  Google Scholar 

  26. Uchiyama S, Makino Y. Digital fluorescent pH sensors. Chem Commun. 2009;19:2646–8.

    Google Scholar 

  27. Zhou K, Wang Y, Huang X, Luby-Phelps K, Sumer BD, Gao J. Tunable, ultrasensitive pH-responsive nanoparticles targeting specific endocytic organelles in living cells. Angew Chem Int Ed. 2011;50(27):6109–14.

    CAS  Google Scholar 

  28. Zhou K, Liu H, Zhang S, Huang X, Wang Y, Huang G, et al. Multicolored pH-tunable and activatable fluorescence nanoplatform responsive to physiologic pH stimuli. J Am Chem Soc. 2012;134(18):7803–11.

    CAS  PubMed  PubMed Central  Google Scholar 

  29. Zhao T, Huang G, Li Y, Yang S, Ramezani S, Lin Z, et al. A transistor-like pH nanoprobe for tumour detection and image-guided surgery. Nat Biomed Eng. 2016;1(1):1–8.

    Google Scholar 

  30. Wang Z, Xia H, Chen B, Wang Y, Yin Q, Yan Y, et al. pH-amplified CRET nanoparticles for in vivo imaging of tumor metastatic lymph nodes. Angew Chem Int Ed. 2021;60(26):14512–20.

    CAS  Google Scholar 

  31. Ling D, Park W, Park S-J, Lu Y, Kim KS, Hackett MJ, et al. Multifunctional tumor pH-sensitive self-assembled nanoparticles for bimodal imaging and treatment of resistant heterogeneous tumors. J Am Chem Soc. 2014;136(15):5647–55.

    CAS  PubMed  Google Scholar 

  32. Yan C, Guo Z, Liu Y, Shi P, Tian H, Zhu W-H. A sequence-activated AND logic dual-channel fluorescent probe for tracking programmable drug release. Chem Sci. 2018;9(29):6176–82.

    CAS  PubMed  PubMed Central  Google Scholar 

  33. Nesterova IV, Nesterov EE. Rational design of highly responsive pH sensors based on DNA i-motif. J Am Chem Soc. 2014;136(25):8843–6.

    CAS  PubMed  Google Scholar 

  34. Yang S-L, Li G, Guo M-Y, Liu W-S, Bu R, Gao E-Q. Positive cooperative protonation of a metal–organic framework: pH-responsive fluorescence and proton conduction. J Am Chem Soc. 2021;143(23):8838–48.

    CAS  PubMed  Google Scholar 

  35. Nesterova IV, Briscoe JR, Nesterov EE. Rational control of folding cooperativity in DNA quadruplexes. J Am Chem Soc. 2015;137(35):11234–7.

    CAS  PubMed  Google Scholar 

  36. Ma W, La Yan, He X, Qing T, Lei Y, Qiao Z, et al. Hairpin-contained i-motif based fluorescent ratiometric probe for high-resolution and sensitive response of small pH variations. Anal Chem. 2018;90(3):1889–96.

    CAS  PubMed  Google Scholar 

  37. Yue X, Qiao Y, Gu D, Qi R, Zhao H, Yin Y, et al. DNA-based pH nanosensor with adjustable FRET responses to track lysosomes and pH fluctuations. Anal Chem. 2021;93(19):7250–7.

    CAS  PubMed  Google Scholar 

  38. Wang H, Di J, Sun Y, Fu J, Wei Z, Matsui H, et al. 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. 2015;25(34):5537–47.

    CAS  Google Scholar 

  39. Chao D, Chen J, Dong Q, Wu W, Qi D, Dong S. Ultrastable and ultrasensitive pH-switchable carbon dots with high quantum yield for water quality identification, glucose detection, and two starch-based solid-state fluorescence materials. Nano Res. 2020;13(11):3012–8.

    CAS  Google Scholar 

  40. Chang B, Li D, Ren Y, Qu C, Shi X, Liu R, et al. A phosphorescent probe for in vivo imaging in the second near-infrared window. Nat Biomed Eng. 2022;6(5):629–39.

    CAS  PubMed  Google Scholar 

  41. Ma J, Li X, Hu Z, Wang X, Zhang Y, Wang W, et al. pH-sensitive assembly/disassembly gold nanoparticles with the potential of tumor diagnosis and treatment. Science China Chem. 2019;62(1):105–17.

    CAS  Google Scholar 

  42. Grimm JB, Sung AJ, Legant WR, Hulamm P, Matlosz SM, Betzig E, et al. Carbofluoresceins and carborhodamines as scaffolds for high-contrast fluorogenic probes. ACS Chem Biol. 2013;8(6):1303–10.

    CAS  PubMed  PubMed Central  Google Scholar 

  43. Grimm JB, Gruber TD, Ortiz G, Brown TA, Lavis LD. Virginia Orange: a versatile, red-shifted fluorescein scaffold for single-and dual-input fluorogenic probes. Bioconj Chem. 2016;27(2):474–80.

    CAS  Google Scholar 

  44. Grimm JB, Brown TA, Tkachuk AN, Lavis LD. General synthetic method for Si-fluoresceins and Si-rhodamines. ACS Cent Sci. 2017;3(9):975–85.

    CAS  PubMed  PubMed Central  Google Scholar 

  45. Yuan J, Peng R, Cheng D, Zou LH, Yuan L. Revealing minor pH changes of mitochondria by a highly sensitive molecular fluorescent probe. Chem Asian J. 2021;16(4):342–7.

    CAS  PubMed  Google Scholar 

  46. Peng R, Yuan J, Cheng D, Ren T, Jin F, Yang R, et al. Evolving a unique red-emitting fluorophore with an optically tunable hydroxy group for imaging nitroreductase in cells, in tissues, and in vivo. Anal Chem. 2019;91(24):15974–81.

    CAS  PubMed  Google Scholar 

  47. Luo X, Yang H, Wang H, Ye Z, Zhou Z, Gu L, et al. Highly sensitive Hill-type small-molecule pH probe that recognizes the reversed pH gradient of cancer cells. Anal Chem. 2018;90(9):5803–9.

    CAS  PubMed  Google Scholar 

  48. Xiao Y, Hu F, Luo X, Zhao M, Sun Z, Qian X, et al. Modulating the pKa values of Hill-type pH probes for biorelevant acidic pH range. ACS Appl Bio Mater. 2020;4(3):2097–103.

    PubMed  Google Scholar 

  49. Lauwerends LJ, van Driel PB, de Jong RJB, Hardillo JA, Koljenovic S, Puppels G, et al. Real-time fluorescence imaging in intraoperative decision making for cancer surgery. Lancet Oncol. 2021;22(5):e186–95.

    CAS  PubMed  Google Scholar 

  50. Jung ME, Piizzi G. gem-Disubstituent effect: theoretical basis and synthetic applications. Chem Rev. 2005;105(5):1735–66.

    CAS  PubMed  Google Scholar 

  51. Xiao Y, Li Y, Hu F, Wang K, Mao Z-W, Luo X, et al. A nucleolus-targeting Hill-type pH probe. Sens Actuators B Chem. 2021;335:129712.

    CAS  Google Scholar 

  52. Hu F, Huang Y, Xiao Y, Li Y, Luo X, Qian X, et al. A dual-channel Hill-type small-molecule pH probe. Anal Methods. 2021;13(27):3012–6.

    CAS  PubMed  Google Scholar 

  53. Yan R, Luo X, Zhou J, Wang P, Yang Y, Qian X, et al. Biodegradable ion-selective nanosensors with p-diethylaminophenol functionalized rhodamine as chromoionophore for metal ions measurements. Sens Actuators B Chem. 2021;336:129672.

    CAS  Google Scholar 

  54. Lin Z, Hu F, He G, Yang Y, Liao Y, Luo X, et al. Highly photostable and pH−sensitive nanosensors. Chemosensors. 2022;10(9):354.

    CAS  Google Scholar 

Download references

Funding

The work is financially supported by the National Natural Science Foundation of China (No. 21908065, 22078098, 22278138).

Author information

Authors and Affiliations

  1. Shanghai Engineering Research Center of Molecular Therapeutics and New Drug Development, School of Chemistry and Molecular Engineering, East China Normal University, Dongchuan Road 500, Shanghai, 200241, China

    Shuhuai Shen, Xiao Luo & Xuhong Qian

  2. State Key Laboratory of Bioreactor Engineering, Shanghai Key Laboratory of Chemical Biology, School of Pharmacy, East China University of Science and Technology, Meilong Road 130, Shanghai, 200237, China

    Youjun Yang & Xuhong Qian

Authors
  1. Shuhuai Shen
    View author publications

    You can also search for this author in PubMed Google Scholar

  2. Youjun Yang
    View author publications

    You can also search for this author in PubMed Google Scholar

  3. Xiao Luo
    View author publications

    You can also search for this author in PubMed Google Scholar

  4. Xuhong Qian
    View author publications

    You can also search for this author in PubMed Google Scholar

Corresponding author

Correspondence to Xiao Luo.

Ethics declarations

Competing interests

The authors declare no competing interests.

Additional information

Publisher's note

Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.

Published in the topical collection Young Investigators in (Bio-)Analytical Chemistry 2023 with guest editors Zhi-Yuan Gu, Beatriz Jurado-Sánchez, Thomas H. Linz, Leandro Wang Hantao, Nongnoot Wongkaew, and Peng Wu.

Rights and permissions

Springer Nature or its licensor (e.g. a society or other partner) holds exclusive rights to this article under a publishing agreement with the author(s) or other rightsholder(s); author self-archiving of the accepted manuscript version of this article is solely governed by the terms of such publishing agreement and applicable law.

Reprints and permissions

About this article

Check for updates. Verify currency and authenticity via CrossMark

Cite this article

Shen, S., Yang, Y., Luo, X. et al. Hill-type pH probes. Anal Bioanal Chem 415, 3693–3702 (2023). https://doi.org/10.1007/s00216-023-04515-y

Download citation

  • Received:

  • Revised:

  • Accepted:

  • Published:

  • Issue Date:

  • DOI: https://doi.org/10.1007/s00216-023-04515-y

Keywords

Search

Navigation