The Effect of Ions on the Optical Absorption Spectra of Aqueously Solvated Chromophores

In the condensed phase, ions often create heterogeneous local environments around a solute, which may impart chemical reactivity or perturbations to physico-chemical properties. Although the former has been the subject of some study, the latter - particularly as is pertains to optical absorption spectroscopy - is much less understood. In this work, the computed UV-Vis absorption spectrum is examined for the aqueously solvated chromophore anion of green fluorescent protein for different local ion configurations. The strong ability of water to screen the ions from the chromophore results in little change in excitation energy compared to a purely aqueous environment. However, upon forming a contact ion pair with a sodium ion at either of the two electronegative oxygen sites of the chromophore, there is a spectral shift to either higher or lower energies. Surprisingly, our analysis suggests that the cause of the spectral shift is dominated not by the electrostatic presence of the ion, but instead by ion disruption of the hydrogen bond network at the oxygen contact ion pair site.

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Silica-Based Nanoparticles for Protein Encapsulation and Delivery

Nanomaterials ◽

10.3390/nano8110886 ◽

2018 ◽

Vol 8 (11) ◽

pp. 886 ◽

Cited By ~ 3

Author(s):

Filippo Begarani ◽

Domenico Cassano ◽

Eleonora Margheritis ◽

Roberto Marotta ◽

Francesco Cardarelli ◽

...

Keyword(s):

Protein Delivery ◽

Fluorescent Protein ◽

Nanoparticle Synthesis ◽

Routine Practice ◽

Aqueous Environment ◽

Protein Encapsulation ◽

Test Protein ◽

Effective Delivery ◽

Green Fluorescent ◽

Acidic Organelles

Although conceptually obvious, the effective delivery of proteins in therapeutic applications is far from being a routine practice. The major limitation is the conservation of protein physicochemical identity during the transport to the target site. In this regard, nanoparticle-based systems offer new intriguing possibilities, provided that (i) the harsh and denaturating conditions typically used for nanoparticle synthesis are avoided or mitigated; and (ii) nanoparticle biocompatibility and degradation (for protein release) are optimized. Here, we tackle these issues by starting from a nanoparticle architecture already tested for small chemical compounds. In particular, silica-shielded liposomes are produced and loaded with a test protein (i.e., Green Fluorescent Protein) in an aqueous environment. We demonstrate promising results concerning protein encapsulation, protection during intracellular trafficking and final release triggered by nanoparticle degradations in acidic organelles. We believe this proof of principle may open new applications and developments for targeted and efficient protein delivery.

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Migration of Salmonella Enteritidis Phage Type 30 through Almond Hulls and Shells

Journal of Food Protection ◽

10.4315/0362-028x-71.2.397 ◽

2008 ◽

Vol 71 (2) ◽

pp. 397-401 ◽

Cited By ~ 29

Author(s):

MICHELLE D. DANYLUK ◽

MARIA T. BRANDL ◽

LINDA J. HARRIS

Keyword(s):

Green Fluorescent Protein ◽

Laser Scanning ◽

Salmonella Enteritidis ◽

Fluorescent Protein ◽

Phage Type ◽

Laser Scanning Microscopy ◽

Confocal Laser ◽

Aqueous Environment ◽

Serovar Typhimurium ◽

Green Fluorescent

The ability of Salmonella to migrate from an external aqueous environment through the almond hull and shell, and to colonize the kernel, was evaluated in two ways. First, the outer surface of shell halves from five varieties of almonds that differed in shell hardness were placed in contact with a suspension of Salmonella enterica serovar Enteritidis phage type 30 for 24hat24°C. Salmonella Enteritidis was isolated from the inside of these almond shells in 46 and 100% of the samples, by direct swabbing of the inner surface of the shell and by enrichment from the swab, respectively. These findings suggested that hardness of the shell is not a significant factor in the migration of the pathogen through that tissue. In addition, both motile and nonmotile strains of S. enterica serovar Typhimurium migrated through the almond shells to the same extent under the conditions of this assay, indicating that bacterial migration through the wet shell may be a passive process. Second, whole almonds (intact hull, shell, and kernel) were soaked for 24 to 72 h at 24°C in a suspension of Salmonella Enteritidis phage type 30 labeled with the green fluorescent protein. Green fluorescent protein–labeled Salmonella cells were observed on the outer and inner surfaces of both the almond hull and shell, and on the kernel, by confocal laser scanning microscopy. Our data provide direct evidence that wet conditions allow for Salmonella migration through the hull and shell and onto the almond kernel, thus providing a means by which almond kernels may become contaminated in the field.

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Sonochemically-induced spectral shift as a probe of green fluorescent protein release from nano capsules

RSC Advances ◽

10.1039/c3ra47915c ◽

2014 ◽

Vol 4 (20) ◽

pp. 10303-10309 ◽

Cited By ~ 1

Author(s):

Ulyana Shimanovich ◽

Anna Munder ◽

Nuno G. Azoia ◽

Artur Cavaco-Paulo ◽

Arie Gruzman ◽

...

Keyword(s):

Green Fluorescent Protein ◽

Fluorescent Protein ◽

Spectral Shift ◽

Protein Release ◽

Green Fluorescent

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Computational Nanochemistry Study of the Molecular Structure, Spectra and Chemical Reactivity Properties of the BFPF Green Fluorescent Protein Chromophore

Biosensors Nanotechnology ◽

10.1002/9781118773826.ch7 ◽

2014 ◽

pp. 199-238

Author(s):

Daniel Glossman-Mitnik

Keyword(s):

Molecular Structure ◽

Green Fluorescent Protein ◽

Fluorescent Protein ◽

Chemical Reactivity ◽

Green Fluorescent

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Linearisation of the effects of spectral shift and stretch in DOAS analysis

Atmospheric Measurement Techniques ◽

10.5194/amt-6-661-2013 ◽

2013 ◽

Vol 6 (3) ◽

pp. 661-675 ◽

Cited By ~ 14

Author(s):

S. Beirle ◽

H. Sihler ◽

T. Wagner

Keyword(s):

Optical Absorption ◽

Linear Equation ◽

Taylor Expansion ◽

Trace Gases ◽

Equation System ◽

Spectral Shift ◽

Optical Absorption Spectroscopy ◽

High Data ◽

Linear Equation System ◽

Data Rates

Abstract. Differential Optical Absorption Spectroscopy (DOAS) is a widely used method to quantify atmospheric trace gases from spectroscopic measurements. While DOAS can, in principal, be described by a linear equation system, usually nonlinearities occur, in particular as a consequence of spectral misalignments. Here we propose to linearise the effects of a spectral shift by including a "shift spectrum", which is the first term of a Taylor expansion, as pseudo-absorber in the DOAS fit. The effects of a spectral stretch are considered as additional wavelength-dependent shifts. Solving the DOAS equation system linearly has several advantages: the solution is unique, the algorithm is robust, and it is very fast. The latter might be particularly important for measurements with high data rates, like for upcoming satellite missions.

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Non-Covalent Associates of siRNAs and AuNPs Enveloped with Lipid Layer and Doped with Amphiphilic Peptide for Efficient siRNA Delivery

International Journal of Molecular Sciences ◽

10.3390/ijms19072096 ◽

2018 ◽

Vol 19 (7) ◽

pp. 2096 ◽

Cited By ~ 9

Author(s):

Julia Poletaeva ◽

Ilya Dovydenko ◽

Anna Epanchintseva ◽

Kseniya Korchagina ◽

Dmitrii Pyshnyi ◽

...

Keyword(s):

Rational Design ◽

Fluorescent Protein ◽

Transfection Efficiency ◽

Sirna Delivery ◽

Chemical Properties ◽

Specific Gene ◽

Delivery Vehicle ◽

Lipid Layer ◽

A Cell ◽

Green Fluorescent

Elaboration of non-viral vehicles for delivery of therapeutic nucleic acids, in particular siRNA, into a cell is an actively growing field. Gold nanoparticles (AuNPs) occupy a noticeable place in these studies, and various nanoconstructions containing AuNPs are reported. We aimed our work to the rational design of AuNPs-based siRNA delivery vehicle with enhanced transfection efficiency. We optimized the obtaining of non-covalent siRNAs-AuNPs cores: ionic strength, temperature and reaction time were determined. Formation of cores was confirmed using gel electrophoresis. Stable associates were prepared, and then enveloped into a lipid layer composed of phosphatidylcholine, phosphatidylethanolamine and novel pH-sensitive lipidoid. The constructions were modified with [Str-(RL)4G-NH2] peptide (the resulting construction). All intermediate and resulting nanoconstructions were analyzed by dynamic light scattering (DLS) and transmission electron microscopy (TEM) to control their physico-chemical properties. To examine the biological effect of the delivery vehicle, green fluorescent protein (GFP)-expressing human embryonic kidney (HEK) Phoenix cells were incubated with the resulting construction containing anti-GFP siRNA, with the siRNA effect being studied by flow cytometry and confocal microscopy. Transfection of the cells with the resulting construction reduced the GFP fluorescence as efficiently as Lipofectamin 3000. Thus, siRNA vehicle based on non-covalently bound siRNA-AuNP core and enveloped into a lipid layer provides efficient delivery of siRNA into a cell followed by specific gene silencing.

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Linearisation of the effects of spectral shift and stretch in DOAS analysis

Atmospheric Measurement Techniques Discussions ◽

10.5194/amtd-5-8369-2012 ◽

2012 ◽

Vol 5 (6) ◽

pp. 8369-8403

Author(s):

S. Beirle ◽

H. Sihler ◽

T. Wagner

Keyword(s):

Optical Absorption ◽

Linear Equation ◽

Taylor Expansion ◽

Trace Gases ◽

Equation System ◽

Spectral Shift ◽

Optical Absorption Spectroscopy ◽

High Data ◽

Linear Equation System ◽

Data Rates

Abstract. Differential Optical Absorption Spectroscopy (DOAS) is a widely used method to quantify atmospheric trace gases from spectroscopic measurements. While DOAS can in principal be described by a linear equation system, usually non-linearities occur, in particular as a consequence of spectral misalignments. Here we propose to linearise the effects of a spectral shift by including a "shift spectrum", which is the first term of a Taylor expansion, as pseudo-absorber in the DOAS fit. The effects of a spectral stretch are considered as additional wavelength-dependent shifts. Solving the DOAS equation system linearly has several advantages: the solution is unique, the algorithm is robust, and it is very fast. The latter might be particularly important for measurements with high data rates, like for upcoming satellite missions.

Download Full-text