Direct electrical detection of hybridization at DNA-modified silicon surfaces

Wet chemical routes to the assembly of organic monolayers on silicon surfaces via the formation of Si–C bonds: surface preparation, passivation and functionalization

“…[31][32][33][34] Silicon-carbon linked monolayers on silicon substrates are expected to complement and/or extend the applications of the currently most relevant technological material 35 toward the development of atomic scale devices, [36][37][38] diverse molecular devices, [39][40][41][42][43][44][45][46][47][48] and well-defined sensing interfaces. [49][50][51][52][53] The following sections are intended as an up-to-date presentation of the topic of molecular layers on non-oxidized silicon surfaces. Particular emphasis is put on outlining the strategies toward the goal of chemically well-defined structures.…”

“…12 and 13, attachment of thiol-modified DNA to the Si(100) surface could be achieved on tert-butoxycarbonyl-protected amine-terminated surfaces (t-BOC protected 1-aminodec-1-ene) after SAM deprotection, and by using a suitable (water soluble) heterobifunctional cross-linker molecule (sulfosuccinimidyl 4-(N-maleimidomethyl) cyclohexane-1-carboxylate, SSMCC). Further applications of aminodecane-modified silicon surfaces, 53,207 alternative protection/ deprotection strategies 86,208 and novel cross-linker molecules (i.e. N-succinimidyl 3-maleimidopropionate, SMP 111 and diluted glutaraldehyde/sodium cyanoborohydride solutions 207 ) have been also reported (Fig.…”

“…Despite not being of major concern in most of the biosensing applications so far published, [50][51][52][53]210,231 the outcome of a multi-step strategy, such as any of those discussed above, is potentially affected by one, or more, of the following shortcomings: (a) cross-reactivity of o-functionalized 1-alkene (or 1-alkyne) molecules with the hydride-terminated silicon surface leading to ambiguous reaction products (e.g. silylester formation 33,214 ); (b) use of poorly controlled activation procedures (e.g.…”

“…changes in the band-bending) and alter the conductivity of the substrate. 53,207 This molecular gate 129 approach has stimulated vast research, 43,63,64,129,278 but despite encouraging recent reports, 279 at present the development of real-world molecular electronics, such as high density memories, 40,41 remain a long-term target. Serious practical obstacles toward the fabrication of a real device still exist.…”

Electrochemical Sensors

“…186 N-and p-type silicon surfaces were chemically modified with amino groups and covalently linked with thiol-modified oligonucleotides probes. The hybridization of target complementary oligonucleotides sequence in the sample solution with the probes resulted in significant changes in both real and imaginary components of the electrical impedance, while exposure to DNA with non-complementary sequences generated negligible responses.…”