Exclusive recognition of sarcosine in water and urine by a cavitand-functionalized silicon surface

Abstract

A supramolecular approach for the specific detection of sarcosine, recently linked to the occurrence of aggressive prostate cancer forms, has been developed. A hybrid active surface was prepared by the covalent anchoring on Si substrates of a tetraphosphonate cavitand as supramolecular receptor and it was proven able to recognize sarcosine from its nonmethylated precursor, glycine, in water and urine. The entire complexation process has been investigated in the solid state, in solution, and at the solid-liquid interface to determine and weight all the factors responsible of the observed specificity. The final outcome is a Si-based active surface capable of binding exclusively sarcosine. The complete selectivity of the cavitand-decorated surface under these stringent conditions represents a critical step forward in the use of these materials for the specific detection of sarcosine and related metabolites in biological fluids. molecular recognition | phosphonate cavitand

Many Simple Molecular Cavitands Are Intrinsically Porous (Zero-Dimensional Pore) Materials

“…[72][73][74][75][76][77][78] Hundreds of synthetic derivatives are known, including dimeric caged forms known as (hemi)carcerands. 79-81 These molecules have been developed, primarily, for exploitation of the rich molecular recognition chemistry exhibited by their shape-persistent concave cavities.…”

Hierarchical Self‐Assembly of Luminescent EuIII Complexes on Silicon

“…Diagnostic upfield shifts of the guest signals were observed, as expected for hosted species that experience the shielding effect of the cavity. [17] In particular, the signals of the N-CH 3 moiety moved over 3 ppm upfield to δ = -0.53 ppm; other resonances attributed to the sarcosine moiety as well as to the phenanthroline unit were also shifted. The 31 P resonance of the four P=O groups moved downfield by almost 5 ppm (from δ = 5.9 to 10.8 ppm; Figure S2 in the Supporting Information).…”

“…towards a sarcosine unit [17] connected to a phenanthroline ligand (1), followed by the coordination of 1 with the europium β-diketonate complex 2 used as the luminescent probe. The related nonluminescent and diamagnetic yttrium β-diketonate 3 was chosen as the reference compound for the NMR spectroscopic characterization in solution and for photophysical control experiments on the surface.…”

“…The design of the connecting ligand was determined by the following experimental observations: (i) the high association constant of sarcosine with tetraphosphonate cavitands, [17] and (ii) the well-known ability of phenanthroline [18,19] to serve as a strong bidentate ligand and efficient sensitizer for Eu III -β-diketonates.…”

Solid-state molecular recognition for supramolecular sensing

“…Phosphonate cavitands are well-known for their ability to complex positively charged species and neutral molecules by a synergistic combination of weak interactions. [2] We have recently demonstrated [3] that a silicon surface decorated with phosphonate cavitands can selectively recognize sarcosine (whose presence in urine is linked with an aggressive form of prostate cancer) from other non-methylated amino acids in biological fluids. The same ability is currently being exploited for the molecular recognition of carboxylic acids of social interest (see Fig.…”