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Microfluidics for Biosensing and Diagnostics
Efforts to miniaturize sensing and diagnostic devices and to integrate multiple functions into one device have caused massive growth in the field of microfluidics and this integration is now recognized as an important feature of most new diagnostic approaches. These approaches have and continue to change the field of biosensing and diagnostics. In this Special Issue, we present a small collection of works describing microfluidics with applications in biosensing and diagnostics
Non-covalent interactions in organotin(IV) derivatives of 5,7-ditertbutyl- and 5,7-diphenyl-1,2,4-triazolo[1,5-a]pyrimidine as recognition motifs in crystalline self- assembly and their in vitro antistaphylococcal activity
Non-covalent interactions are known to play a key role in biological compounds due to their
stabilization of the tertiary and quaternary structure of proteins [1]. Ligands similar to purine rings,
such as triazolo pyrimidine ones, are very versatile in their interactions with metals and can act as
model systems for natural bio-inorganic compounds [2]. A considerable series (twelve novel
compounds are reported) of 5,7-ditertbutyl-1,2,4-triazolo[1,5-a]pyrimidine (dbtp) and 5,7-diphenyl-
1,2,4-triazolo[1,5-a]pyrimidine (dptp) were synthesized and investigated by FT-IR and 119Sn
M\uf6ssbauer in the solid state and by 1H and 13C NMR spectroscopy, in solution [3]. The X-ray
crystal and molecular structures of Et2SnCl2(dbtp)2 and Ph2SnCl2(EtOH)2(dptp)2 were described, in
this latter pyrimidine molecules are not directly bound to the metal center but strictly H-bonded,
through N(3), to the -OH group of the ethanol moieties. The network of hydrogen bonding and
aromatic interactions involving pyrimidine and phenyl
rings in both complexes drives their self-assembly. Noncovalent
interactions involving aromatic rings are key
processes in both chemical and biological recognition,
contributing to overall complex stability and forming
recognition motifs. It is noteworthy that in
Ph2SnCl2(EtOH)2(dptp)2 \u3c0\u2013\u3c0 stacking interactions between
pairs of antiparallel triazolopyrimidine rings mimick basepair
interactions physiologically occurring in DNA (Fig.1).
M\uf6ssbauer spectra suggest for Et2SnCl2(dbtp)2 a
distorted octahedral structure, with C-Sn-C bond angles
lower than 180\ub0. The estimated angle for Et2SnCl2(dbtp)2
is virtually identical to that determined by X-ray diffraction. Ph2SnCl2(EtOH)2(dptp)2 is
characterized by an essentially linear C-Sn-C fragment according to the X-ray all-trans structure.
The compounds were screened for their in vitro antibacterial activity on a group of reference
staphylococcal strains susceptible or resistant to methicillin and against two reference Gramnegative
pathogens [4] . We tested the biological activity of all the specimen against a group of
staphylococcal reference strains (S. aureus ATCC 25923, S. aureus ATCC 29213, methicillin
resistant S. aureus 43866 and S. epidermidis RP62A) along with Gram-negative pathogens (P.
aeruginosa ATCC9027 and E. coli ATCC25922). Ph2SnCl2(EtOH)2(dptp)2 showed good
antibacterial activity with a MIC value of 5 \u3bcg mL-1 against S. aureus ATCC29213 and also
resulted active against methicillin resistant S. epidermidis RP62A