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Ghosh G, Roy DS, Ghosh R, Mukherjee D, Biswas S, Roy L, Chattopadhyay A, Das R, Pal SK. Excited-State Dynamics of a Photoacid: A Potential Probe for Recognizing Transition from Lamellar to Nonlamellar Inverted Structures of Liposome based Nanocarriers. Chemphyschem 2024; 25:e202300635. [PMID: 37936318 DOI: 10.1002/cphc.202300635] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2023] [Revised: 11/04/2023] [Accepted: 11/07/2023] [Indexed: 11/09/2023]
Abstract
Liposomes of a cationic lipid dioctadecyldimethylammonium bromide (DODAB) are efficient nanocarriers of nucleic acids. Incorporation of a neutral lipid monoolein (MO) in excess (xMO >0.5) changes the lamellar organization of DODAB liposomes into non-lamellar inverted structures of DODAB/MO liposomes facilitating nucleic acid delivery to cells. Photoexcitation of 8-hydroxypyrene-1,3,6-trisulfonic acid (HPTS), a photoacid, initiates an excited state proton transfer (ESPT) reaction in its protonated form (ROH*) generating the deprotonated anionic form (RO- *). The fluorescence intensity ratio (IROH* /IRO-* ) of these two forms is governed by the ESPT dynamics, and increases with increasing MO content (xMO ) in the cationic liposomes of DODAB. Transition from lamellar organization of DODAB liposomes into non-lamellar inverted structures of DODAB/MO liposomes, due to incorporation of MO (xMO ~0.7), is manifested by a significant increase of ESPT time (τPT ) and the time constant of wobbling motion (τW ) of HPTS. Thus, the lamellar organizations of DODAB or DODAB-rich (xMO 0.2) liposomes and the non-lamellar organizations of MO-rich (xMO ~0.7) liposomes are recognized by significantly different excited state dynamics of the photoacid.
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Affiliation(s)
- Gourab Ghosh
- Dept. of Chemistry, West Bengal State University, Barasat, Kolkata, 700126, India
| | - Debanjana Singha Roy
- Dept. of Chemistry, West Bengal State University, Barasat, Kolkata, 700126, India
- Department of Chemical, Biological & Macromolecular Sciences, S. N. Bose National Centre for Basic Sciences, Block JD, Sector III, Salt Lake, Kolkata, India
| | - Ria Ghosh
- Technical Research Centre, S. N. Bose National Centre for Basic Sciences, Kolkata, India
| | - Dipanjan Mukherjee
- Department of Chemical, Biological & Macromolecular Sciences, S. N. Bose National Centre for Basic Sciences, Block JD, Sector III, Salt Lake, Kolkata, India
| | - Suman Biswas
- Dept. of Chemistry, West Bengal State University, Barasat, Kolkata, 700126, India
| | - Lopamudra Roy
- Department of Applied Optics and Photonics, University of Calcutta, 92, Acharya Prafulla Chandra Rd, Kolkata, 700009, India
| | - Arpita Chattopadhyay
- Department of Basic science and humanities, Techno International New Town, Rajarhat, Kolkata, 700156
| | - Ranjan Das
- Dept. of Chemistry, West Bengal State University, Barasat, Kolkata, 700126, India
| | - Samir Kumar Pal
- Department of Chemical, Biological & Macromolecular Sciences, S. N. Bose National Centre for Basic Sciences, Block JD, Sector III, Salt Lake, Kolkata, India
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Leier J, Michenfelder NC, Unterreiner AN, Olzmann M. Indications for an intermolecular photo-induced excited-state proton transfer of p-nitrophenol in water. Mol Phys 2021. [DOI: 10.1080/00268976.2021.1975051] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
Affiliation(s)
- Julia Leier
- Institut für Physikalische Chemie, Karlsruher Institut für Technologie (KIT), Karlsruhe, Germany
| | - Nadine C. Michenfelder
- Institut für Physikalische Chemie, Karlsruher Institut für Technologie (KIT), Karlsruhe, Germany
| | - Andreas-Neil Unterreiner
- Institut für Physikalische Chemie, Karlsruher Institut für Technologie (KIT), Karlsruhe, Germany
| | - Matthias Olzmann
- Institut für Physikalische Chemie, Karlsruher Institut für Technologie (KIT), Karlsruhe, Germany
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Liu ZY, Hu JW, Huang TH, Chen KY, Chou PT. Excited-state intramolecular proton transfer in the kinetic-control regime. Phys Chem Chem Phys 2020; 22:22271-22278. [PMID: 33001109 DOI: 10.1039/d0cp03408h] [Citation(s) in RCA: 30] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
A new series of molecules bearing a 2,11-dihydro-1H-cyclopenta[de]indeno[1,2-b]quinoline (CPIQ) chromophore with the N-HN type of intramolecular hydrogen bond are strategically designed and synthesized, among which CPIQ-OH, CPIQ-NHAc and CPIQ-NHTs in solution exhibit a single emission band with an anomalously large Stokes shift, whereas CPIQ-NH2 and CPIQ-NHMe show apparent dual-emission property. This, in combination with time-resolved spectroscopy and the computational approach, leads us to conclude that CPIQ-OH, CPIQ-NHAc and CPIQ-NHTs undergo ultrafast, highly exergonic excited-state intramolecular proton transfer (ESIPT), while a finite rate of ESIPT is observed for CPIQ-NH2 and CPIQ-NHMe with a time constant of 117 ps and 39 ps, respectively, in acetonitrile at room-temperature. Further temperature-dependent studies deduce an appreciable ESIPT barrier for CPIQ-NH2 and CPIQ-NHMe. Different from most of the barrier associated ESIPT molecules that are commonly in the thermodynamic-control regime, i.e. found in the thermal pre-equilibrium between excited normal and proton-transfer tautomer states, CPIQ-NH2 and CPIQ-NHMe cases are in the kinetic-control regime where ESIPT is irreversible with a significant barrier. The barrier is able to be tuned by the electronic properties of the -R group in the NR-H proton donor site, resulting in ratiometric fluorescence for normal versus tautomer emission.
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Affiliation(s)
- Zong-Ying Liu
- Department of Chemistry, National Taiwan University, Taipei, 10617 Taiwan, Republic of China.
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Affiliation(s)
- Nadav Amdursky
- Schulich Faculty of ChemistryTechnion – Israel Institute of Technology Haifa 3200003 Israel
| | - Yiyang Lin
- State Key Laboratory of Organic-Inorganic Composites Beijing Laboratory of Biomedical MaterialsBeijing University of Chemical Technology Beijing 100029 China
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Exploring fast proton transfer events associated with lateral proton diffusion on the surface of membranes. Proc Natl Acad Sci U S A 2019; 116:2443-2451. [PMID: 30679274 DOI: 10.1073/pnas.1812351116] [Citation(s) in RCA: 39] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Proton diffusion (PD) across biological membranes is a fundamental process in many biological systems, and much experimental and theoretical effort has been employed for deciphering it. Here, we report on a spectroscopic probe, which can be tightly tethered to the membrane, for following fast (nanosecond) proton transfer events on the surface of membranes. Our probe is composed of a photoacid that serves as our light-induced proton source for the initiation of the PD process. We use our probe to follow PD, and its pH dependence, on the surface of lipid vesicles composed of a zwitterionic headgroup, a negative headgroup, a headgroup that is composed only from the negative phosphate group, or a positive headgroup without the phosphate group. We reveal that the PD kinetic parameters are highly sensitive to the nature of the lipid headgroup, ranging from a fast lateral diffusion at some membranes to the escape of protons from surface to bulk (and vice versa) at others. By referring to existing theoretical models for membrane PD, we found that while some of our results confirm the quasi-equilibrium model, other results are in line with the nonequilibrium model.
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Krishnakumar P, Kar R, Maity DK. Microhydration of 2-Naphthol at Ground, First Excited Triplet, and First Excited Singlet States: A Case Study on Photo Acids. J Phys Chem A 2018; 122:929-936. [PMID: 29320857 DOI: 10.1021/acs.jpca.7b09579] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Molecular interactions of 2-naphthol (nap) with water molecules are studied at the ground, first excited triplet and first excited singlet states, applying DFT and TD-DFT methods. The minimum energy structure of hydrated clusters of 2-naphthol up to four water molecules are selected from several possible input geometries. It is observed that the minimum energy conformer of the tetra-hydrate of 2-naphthol has proton transfer occurring from nap to solvent water molecules, in its first excited singlet state. This is however not observed in case of its ground or first excited triplet state. It is consistent with the fact that the pKa of nap in the first excited singlet state is very much lower compared to the ground and first excited triplet state. This is also reflected in the O-H potential energy profile of tetrahydrate of nap, obtained by performing a rigid potential energy scan of the dissociating O-H bond of nap at ground, first excited triplet and first excited singlet states. Frequency of O-H stretching vibration of 2-napthol and its hydrated clusters in the ground (S0) as well as in the first excited singlet (S1) state are calculated and compared with the available experimental data. The performance of macroscopic solvation model is also examined in the ground and these excited states.
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Affiliation(s)
- Parvathi Krishnakumar
- Homi Bhabha National Institute , Training School Complex, Anushaktinagar, Mumbai-400094, India.,Bhabha Atomic Research Centre , Mumbai-400085, India
| | - Rahul Kar
- Department of Chemistry, Dibrugarh University , Dibrugarh-786004, Assam, India
| | - Dilip Kumar Maity
- Homi Bhabha National Institute , Training School Complex, Anushaktinagar, Mumbai-400094, India.,Bhabha Atomic Research Centre , Mumbai-400085, India
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Amdursky N, Rashid MH, Stevens MM, Yarovsky I. Exploring the binding sites and proton diffusion on insulin amyloid fibril surfaces by naphthol-based photoacid fluorescence and molecular simulations. Sci Rep 2017; 7:6245. [PMID: 28740173 PMCID: PMC5524688 DOI: 10.1038/s41598-017-06030-4] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2017] [Accepted: 06/09/2017] [Indexed: 11/18/2022] Open
Abstract
The diffusion of protons along biological surfaces and the interaction of biological structures with water are fundamental areas of interest in biology and chemistry. Here, we examine the surface of insulin amyloid fibrils and follow the binding of small molecules (photoacids) that differ according to the number and location of their sulfonic groups. We use transient fluorescence combined with a spherically-symmetric diffusion theory to show that the binding mode of different photoacids determines the efficiency of proton dissociation from the photoacid and the dimensionality of the proton’s diffusion. We use molecular dynamics simulations to examine the binding mode and mechanism of the photoacids and its influence on the unique kinetic rates and diffusion properties of the photoacid’s dissociated proton, where we also suggest a proton transfer process between one of the photoacids to proximal histidine residues. We show that the photoacids can be used as fluorescent markers for following the progression of amyloidogenic processes. The detailed characterisation of different binding modes to the surface of amyloid fibrils paves the way for better understanding of the binding mechanism of small molecules to amyloid fibrils.
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Affiliation(s)
- Nadav Amdursky
- Department of Materials, Department of Bioengineering and Institute of Biomedical Engineering, Imperial College London, London, SW7 2AZ, United Kingdom. .,Schulich Faculty of Chemistry, Technion - Israel Institute of Technology, Haifa, 3200003, Israel.
| | - M Harunur Rashid
- School of Engineering, RMIT University, Melbourne, Victoria, 3001, Australia
| | - Molly M Stevens
- Department of Materials, Department of Bioengineering and Institute of Biomedical Engineering, Imperial College London, London, SW7 2AZ, United Kingdom
| | - Irene Yarovsky
- School of Engineering, RMIT University, Melbourne, Victoria, 3001, Australia.
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Amdursky N. Photoacids as a new fluorescence tool for tracking structural transitions of proteins: following the concentration-induced transition of bovine serum albumin. Phys Chem Chem Phys 2016; 17:32023-32. [PMID: 26573990 DOI: 10.1039/c5cp05548b] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Spectroscopy-based techniques for assessing structural transitions of proteins follow either an intramolecular chromophore, as in absorption-based circular dichroism (CD) or fluorescence-based tryptophan emission, or an intermolecular chromophore such as fluorescent probes. Here a new fluorescent probe method to probe the structural transition of proteins by photoacids is presented, which has a fundamentally different photo-physical origin to that of common fluorescent probes. Photoacids are molecules that release a proton upon photo-excitation. By following the steady-state and time-resolved emission of the protonated and de-protonated species of the photoacid we probe the environment of its binding site in bovine serum albumin (BSA) in a wide range of weight concentrations (0.001-8%). We found a unique concentration-induced structural transition of BSA at pH2 and at concentrations of >0.75%, which involves the exposure of its hydrophobic core to the solution. We confirm our results with the common tryptophan emission method, and show that the use of photoacids can result in a much more sensitive tool. We also show that common fluorescent probes and the CD methodologies have fundamental restrictions that limit their use in a concentration-dependent study. The use of photoacids is facile and requires only a fluorospectrometer (and preferably, but not mandatorily, a time-resolution emission system). The photoacid can be either non-covalently (as in this study) or covalently attached to the molecule, and can be readily employed to follow the local environment of numerous (bio-)systems.
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Affiliation(s)
- Nadav Amdursky
- Departments of Materials and Bioengineering, Imperial College London, London, SW7 2AZ, UK.
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Amdursky N, Wang X, Meredith P, Bradley DDC, Stevens MM. Long-Range Proton Conduction across Free-Standing Serum Albumin Mats. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2016; 28:2692-8. [PMID: 26840865 PMCID: PMC4862025 DOI: 10.1002/adma.201505337] [Citation(s) in RCA: 46] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/30/2015] [Revised: 11/28/2015] [Indexed: 05/26/2023]
Abstract
Free-standing serum-albumin mats can transport protons over millimetre length-scales. The results of photoinduced proton transfer and voltage-driven proton-conductivity measurements, together with temperature-dependent and isotope-effect studies, suggest that oxo-amino-acids of the protein serum albumin play a major role in the translocation of protons via an "over-the-barrier" hopping mechanism. The use of proton-conducting protein mats opens new possibilities for bioelectronic interfaces.
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Affiliation(s)
- Nadav Amdursky
- Departments of Materials, Bioengineering and Institute of Biomedical Engineering, Imperial College London, London, SW7 2AZ, UK
| | - Xuhua Wang
- Department of Physics and Centre for Plastic Electronics, Imperial College London, London, SW7 2AZ, UK
| | - Paul Meredith
- Centre for Organic Photonics and Electronics, School of Mathematics and Physics, University of Queensland, Brisbane, Queensland, 4072, Australia
| | - Donal D C Bradley
- Department of Physics and Centre for Plastic Electronics, Imperial College London, London, SW7 2AZ, UK
| | - Molly M Stevens
- Departments of Materials, Bioengineering and Institute of Biomedical Engineering, Imperial College London, London, SW7 2AZ, UK
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Simkovitch R, Huppert D. Excited-State Proton Transfer in Resveratrol and Proposed Mechanism for Plant Resistance to Fungal Infection. J Phys Chem B 2015; 119:11684-94. [PMID: 26247232 DOI: 10.1021/acs.jpcb.5b06440] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Steady-state and time-resolved fluorescence techniques were employed to study the photophysics and photochemistry of trans-resveratrol. trans-Resveratrol is found in large quantities in fungi-infected grapevine-leaf tissue and plays a direct role in the resistance to plant disease. We found that trans-resveratrol in liquid solution undergoes a trans-cis isomerization process in the excited state at a rate that depends partially on the solvent viscosity, as was found in previous studies on trans-stilbene. The hydroxyl groups of the phenol moieties in resveratrol are weak photoacids. In water and methanol solutions containing weak bases such as acetate, a proton is transferred to the base within the lifetime of the excited state. When resveratrol is adsorbed on cellulose (also a component of the plant's cell wall), the cis-trans process is slow and the lifetime of the excited state increases from several tens of picoseconds in ethanol to about 1.5 ns. Excited-state proton transfer occurs when resveratrol is adsorbed on cellulose and acetate ions are in close proximity to the phenol moieties. We propose that proton transfer from excited resveratrol to the fungus acid-sensing chemoreceptor is one of the plant's resistance mechanisms to fungal infection.
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Affiliation(s)
- Ron Simkovitch
- Raymond and Beverly Sackler Faculty of Exact Sciences, School of Chemistry, Tel Aviv University , Tel Aviv 69978, Israel
| | - Dan Huppert
- Raymond and Beverly Sackler Faculty of Exact Sciences, School of Chemistry, Tel Aviv University , Tel Aviv 69978, Israel
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Yang M. Effects of Coulombic Interaction in Diffusion-influenced Reversible Proton Transfer Kinetics of Photoexcited Acids. B KOREAN CHEM SOC 2015. [DOI: 10.1002/bkcs.10385] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Affiliation(s)
- Mino Yang
- Department of Chemistry; Chungbuk National University; Cheongju 361-763 Korea
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Simkovitch R, Huppert D. Excited-State Proton Transfer of Weak Photoacids Adsorbed on Biomaterials: Proton Transfer on Starch. J Phys Chem B 2015; 119:9795-804. [DOI: 10.1021/acs.jpcb.5b04510] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Ron Simkovitch
- Raymond and Beverly Sackler
Faculty of Exact Sciences, School of Chemistry, Tel Aviv University, Tel Aviv 69978, Israel
| | - Dan Huppert
- Raymond and Beverly Sackler
Faculty of Exact Sciences, School of Chemistry, Tel Aviv University, Tel Aviv 69978, Israel
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Simkovitch R, Huppert D. Excited-state proton transfer of weak photoacids adsorbed on biomaterials: 8-hydroxy-1,3,6-pyrenetrisulfonate on chitin and cellulose. J Phys Chem A 2015; 119:1973-82. [PMID: 25692323 DOI: 10.1021/acs.jpca.5b01398] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Time-resolved and steady-state florescence measurements were used to study the photoprotolytic process of an adsorbed photoacid on cellulose and chitin. For that purpose we used the 8-hydroxy-1,3,6-pyrenetrisulfonate (HPTS) photoacid which transfers a proton to water with a time constant of 100 ps, but is incapable of doing so in methanol or ethanol. We found that both biopolymers accept a proton from the electronically excited acidic ROH form of HPTS. The excited-state proton-transfer (ESPT) rate of HPTS adsorbed on chitin is greater than that on cellulose by a factor of 5. The ESPT on chitin also occurs in the presence of methanol or ethanol, but at a slower rate. The transferred protons can recombine efficiently with the conjugate excited base, the RO(-) form of HPTS.
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Affiliation(s)
- Ron Simkovitch
- Raymond and Beverly Sackler Faculty of Exact Sciences, School of Chemistry, Tel Aviv University , Tel Aviv 69978, Israel
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