5 research outputs found
DrugāDrug Interactions within Protein Cavities Probed by TripletāTriplet Energy Transfer
A new direct and
noninvasive methodology based on transient absorption
spectroscopy has been developed to probe the feasibility of drugādrug
interactions within a common protein binding site. The simultaneous
presence of (<i>R</i>)-cinacalcet (CIN) and (<i>S</i>)-propranolol (PPN) within human or bovine Ī±<sub>1</sub>-acid
glycoproteins (AAGs) is revealed by detection of <sup>3</sup>CIN*
as the only transient species after laser flash photolysis of CIN/PPN/AAG
mixtures at 308 nm. This is the result of tripletātriplet energy
transfer from <sup>3</sup>PPN* to CIN, which requires close contact
between the two drugs within the same biological compartment. Similar
results are obtained with nabumetone and CIN as donor/acceptor partners.
This new methodology can, in principle, be extended to a variety of
drug/drug/biomolecule combinations
Photophysical Probes To Assess the Potential of Cholic Acid Aggregates as Drug Carriers
The two enantiomers of the nonsteroidal antiinflammatory
drug naproxen
and of its methyl ester have been selected as representative probes
with markedly different hydrophobicity to assess the potential of
cholic acid aggregates as drug carriers by means of photophysical
techniques. The different distribution of the probes between bulk
solution and aggregates has been assessed by quenching of their singlet
and triplet excited states by iodide and nitrite anions, respectively.
This straightforward photophysical methodology can, in principle,
be extended to a variety of drugs containing a photoactive chromophore
Fundamental Insights into the Reductive Covalent Cross-Linking of Single-Walled Carbon Nanotubes
Single-walled
carbon nanotubes (SWCNT) have been covalently cross-linked
via a reductive functionalization pathway, utilizing negatively charged
carbon nanotubides (KC<sub>4</sub>). We have compared the use of difunctional
linkers acting as molecular pillars between the nanotubes, namely, <i>p</i>-diiodobenzene, <i>p</i>-diiodobiphenyl, benzene-4,4ā²-bisĀ(diazonium),
and 1,1ā²-biphenyl-4,4ā²-bisĀ(diazonium) salts as electrophiles.
We have employed statistical Raman spectroscopy (SRS), a forefront
characterization tool consisting of thermogravimetric analysis coupled
with gas chromatography and mass spectrometry (TG-GC-MS) and aberration-corrected
high-resolution transmission electron microscopy imaging series at
80 kV to unambiguously demonstrate the covalent binding of the molecular
linkers. The present study shows that the SWCNT functionalization
using iodide derivatives leads to the best results in terms of bulk
functionalization homogeneity (<i>H</i><sub>bulk</sub>)
and degree of addition. Phenylene linkers yield the highest degree
of functionalization, whereas biphenylene units induce a higher surface
area with an increase in the thermal stability and an improved electrochemical
performance in the oxygen reduction reaction (ORR). This work illustrates
the importance of molecular engineering in the design of novel functional
materials and provides important insights into the understanding of
basic principles of reductive cross-linking of carbon nanotubes
Fundamental Insights into the Reductive Covalent Cross-Linking of Single-Walled Carbon Nanotubes
Single-walled
carbon nanotubes (SWCNT) have been covalently cross-linked
via a reductive functionalization pathway, utilizing negatively charged
carbon nanotubides (KC<sub>4</sub>). We have compared the use of difunctional
linkers acting as molecular pillars between the nanotubes, namely, <i>p</i>-diiodobenzene, <i>p</i>-diiodobiphenyl, benzene-4,4ā²-bisĀ(diazonium),
and 1,1ā²-biphenyl-4,4ā²-bisĀ(diazonium) salts as electrophiles.
We have employed statistical Raman spectroscopy (SRS), a forefront
characterization tool consisting of thermogravimetric analysis coupled
with gas chromatography and mass spectrometry (TG-GC-MS) and aberration-corrected
high-resolution transmission electron microscopy imaging series at
80 kV to unambiguously demonstrate the covalent binding of the molecular
linkers. The present study shows that the SWCNT functionalization
using iodide derivatives leads to the best results in terms of bulk
functionalization homogeneity (<i>H</i><sub>bulk</sub>)
and degree of addition. Phenylene linkers yield the highest degree
of functionalization, whereas biphenylene units induce a higher surface
area with an increase in the thermal stability and an improved electrochemical
performance in the oxygen reduction reaction (ORR). This work illustrates
the importance of molecular engineering in the design of novel functional
materials and provides important insights into the understanding of
basic principles of reductive cross-linking of carbon nanotubes
Fundamental Insights into the Reductive Covalent Cross-Linking of Single-Walled Carbon Nanotubes
Single-walled
carbon nanotubes (SWCNT) have been covalently cross-linked
via a reductive functionalization pathway, utilizing negatively charged
carbon nanotubides (KC<sub>4</sub>). We have compared the use of difunctional
linkers acting as molecular pillars between the nanotubes, namely, <i>p</i>-diiodobenzene, <i>p</i>-diiodobiphenyl, benzene-4,4ā²-bisĀ(diazonium),
and 1,1ā²-biphenyl-4,4ā²-bisĀ(diazonium) salts as electrophiles.
We have employed statistical Raman spectroscopy (SRS), a forefront
characterization tool consisting of thermogravimetric analysis coupled
with gas chromatography and mass spectrometry (TG-GC-MS) and aberration-corrected
high-resolution transmission electron microscopy imaging series at
80 kV to unambiguously demonstrate the covalent binding of the molecular
linkers. The present study shows that the SWCNT functionalization
using iodide derivatives leads to the best results in terms of bulk
functionalization homogeneity (<i>H</i><sub>bulk</sub>)
and degree of addition. Phenylene linkers yield the highest degree
of functionalization, whereas biphenylene units induce a higher surface
area with an increase in the thermal stability and an improved electrochemical
performance in the oxygen reduction reaction (ORR). This work illustrates
the importance of molecular engineering in the design of novel functional
materials and provides important insights into the understanding of
basic principles of reductive cross-linking of carbon nanotubes