4th EucheMs chemistry congress

Poster Session 2
s1252
chem. Listy 106, s257–s1425 (2012)
Poster session 2 - Nanochemistry, Nanotechnology
P - 0 7 7 9
CheMiCAL ModifiCAtion And StruCturAL
ChArACterizAtion of ti6AL4v ALLoy
SurfACeS
A. rodríGuez-CAno 1 , r. BABiAno 2 , P. CintAS 2 ,
M. L. GonzáLez-MArtín 3
1 Universidad de Extremadura. Centro de Investigación
Biomédica en Red en Bioingeniería Biomateriales y
Nanomedicina (CIBER-BBN), Química Orgánica e
Inorgánica, Badajoz, Spain
2 Universidad de Extremadura, Química Orgánica e Inorgánica,
Badajoz, Spain
3 Universidad de Extremadura. Centro de Investigación
Biomédica en Red en Bioingeniería Biomateriales y
Nanomedicina (CIBER-BBN), Física Aplicada, Badajoz, Spain
Titanium-based medical implants are employed worldwide
in bone repair. The success of this sort of regenerative medicine
depends critically on appropriate chemical functionalization of
the titanium surface that facilitates osseointegration, while
decreasing bacterial adhesion and biofilm formation caused by
quorum sensing mechanisms [1] . A common strategy involves the
creation of siloxane chains attached to the metal surface and
ending in halogen or amino functional groups, which further react
with an organic partner that enhances the biocompatibility [2] .
We report herein a robust amination of Ti6Al4V, an alloy
of broad use in medical prostheses, via reaction with
(3-aminopropyl)trimethoxysilane. The resulting polysiloxane
network had a maximum coverage of amino groups, which
underwent coupling with reactive organic molecules affording
thin films on the alloy. Thus, alkyl and aryl isocyanates reacted
smoothly to give the corresponding ureas. On the other hand,
reaction with cinnamaldehyde gave rise to a more labile imino
linkage, which can break under acidic conditions, thereby
releasing this bioactive aldehyde.
Structural characterization of these chemically-modified
surfaces was accomplished by FTIR-ATR, XPS, and SEM
analyses. Amino group densities were monitored through
ninhydrin assays. Controlled liberation of cinnamaldehyde was
also checked by UV-Vis spectrophotometry and results were
compared with those obtained via XPS. Studies aimed at
evaluating cell proliferation as well as resistance to bacterial
adhesion and growth are currently under way.
Acknowledgments. This work was supported by grants from the
Ministry of Science and Innovation (MAT2009-14695-C04-01
and CTQ2010-18938), Gobierno de Extremadura (Ayudas a
Grupos Consolidados: GR10049 and GR10149) and FEDER
(Fondo Europeo de Desarrollo Regional, Una Manera de
Hacer Europa). One of us (ARC) thanks the Ministry for a
scholarship (BES-2010-033417).
references:
1. Amara N, Krom BP, Kaufmann GF, Meijler MM. Chem
Rev 2011, 111, 195-208.
2. Silverman BM, Wieghaus KA, Schwartz J. Langmuir
2005, 21, 225-228.
Keywords: surface chemistry; material science; titanium;
alloys; self-assembly;
4 th EucheMs chemistry congress
P - 0 7 8 0
PorPhyrin BindinG And SeLf-AGGreGAtion
MediAted By A PoLyeLeCtroLyte MAtrix
A. roMeo 1 , M. A. CAStriCiAno 2 ,
L. MonSu SCoLAro 1
1 University of Messina, Inorganic Analytical and Physical
Chemistry, Messina, Italy
2 ISMN, CNR, Messina, Italy
Non-covalent self-assembly is an ubiquitous process in
biology and it represents an effective tool in order to access to a
large variety of structures with sizes spanning from nano- to
mesoscopic scale showing different architectures and
functionalities. Supramolecular species containing porphyrins are
interesting from a fundamental viewpoint as they offer the
possibility of mimicking photosynthetic centers and of accessing
to supramolecular devices. In this respect, charged biopolymers,
e.g. DNA, RNA, polypeptides and even filamentous
bacteriophages [1] have been exploited to organize oppositely
charged porphyrins in tailored assemblies. In this framework, the
employment of simple polyelectrolyte templates allows to reduce
the number of interaction modes of the porphyrin on the scaffold
so affording i) to a larger stability in the formation of porphyrin
aggregates in solution, as well as in the solid state and ii) to a
better assessing of the interaction mechanism between the
polymer scaffold and the chromophores. [2] Poly(sodium
vinylsulfonate) (PVS), completely dissociated from its gegen ion
in aqueous solution, represents an efficient and versatile highly
charged polyanion template for binding various cationic species
exclusively through Electrostatic Self-Assembly. Here we report
on the interaction of this polymer with the tetracationic
water soluble meso-tetrakis(N-methylpyridinium-4-yl)porphine
(TMpyP) and some its metal derivatives (Cu(II), Zn(II), Mn(III),
Au(III)) under different experimental conditions. We present
evidence that, depending on pH, the high electrostatic field of
PVS stabilizes the diprotonated form of the free base porphyrin
at unusual pH values and causes the formation of H-type
aggregates.
references:
1. L. M. Scolaro, M. A. Castriciano, A. Romeo, N. Micali,
N. Angelini, C. Lo Passo, F. Felici, J. Am. Chem. Soc.,
2006, 128, 7446.
2. L. M. Scolaro, A. Romeo, A. Terracina, Chem. Commun.,
1997, 1451.
Keywords: porphyrin; aggregation; supramolecular chemistry;
polyelectrolyte; spectroscopic investigation;
AUGUst 26–30, 2012, PrAGUE, cZEcH rEPUbLIc