Surface-enhanced Raman spectroscopy: bottlenecks and future directions

Abstract

In this feature article, we discuss in detail developmental bottleneck issues in Raman spectroscopy in its early stages and surface-enhanced Raman spectroscopy (SERS) in the past four decades. We divide SERS research into two different directions with different targets. Fundamental research is extending the limits of SERS to single-molecule, sub-nanometer resolution and femtosecond processes. In contrast, practical research is expanding the range of applications with the aim of providing versatile analytical tools for surface, materials, life, environmental, forensic and food sciences and also commercial instruments for use in daily life. In the second direction there have continually been many complex bottlenecks to be overcome. We attempt to enumerate the key issues in detail and also describe the achievements made to overcome the bottlenecks. In the last, but not least important part, we discuss the remaining bottlenecks and possible strategies for overcoming them to enable SERS to be an even more powerful and versatile technique.

Raman photostability of off-resonant gap-enhanced Raman tags

“…[1][2][3][4][5][6][7] With the unique ngerprint spectral feature, SERS nanoprobes, namely, metallic nanoparticles together with molecules as Raman reporters, have been extensively investigated for the biomedical applications including biosensing and bioimaging similar to the uorescent nanoprobes. [8][9][10][11][12][13][14] In contrast to uorophores, SERS nanoprobes exhibit a much larger multiplexing capability due to the narrow spectral linewidth. In addition, SERS nanoprobes show better stability than uorophores since uorophores easily suffer the photobleaching issue caused by modication of covalent bonds or non-specic reactions between the uorophores and surrounding molecules upon singlet statetriplet state transition, 15,16 which is especially problematic in time-lapse microscopy.…”

SERS background imaging – A versatile tool towards more reliable SERS analytics

“…The most remarkable property of surface-enhanced Raman scattering (SERS) is probably its capability to enhance the Raman effect up to the level of single molecular detection 1,2 . Nevertheless, SERS did not yet achieve a breakthrough on the commercial market or even high impact in applied analytical research 3 . This is due to its challenging reproducibility and reliability, taking effect especially in highly sensitive so-called hot spot-based SERS measurements [3][4][5][6][7][8] .…”

“…The SERS effect is a complex process based on a three-body interaction of photons, molecules and nanostructures 3 . These nanostructures, in the following named SERS substrate, play a special role as they not only act as a signal ampli er but also must enable adsorption of or at least close contact to the analyte, as the enhancement decreases exponentially with distance 3 . Highest electromagnetic enhancement -the main contributor of the SERS effect -is only obtained in localised optical near-elds, the so-called 'hot spots' appearing in interparticle nanogaps (< 10 nm) formed e.g.…”

Двухволновая Лазерная Стереолитография Для Создания ИК Сенсоров Для Поверхностно-Усиленной Спектроскопии-=sup=-*-=/Sup=-

“…Это явление обусловлено адсорбцией молекул на поверхности металлов, связанной с сильными межмолекулярными взаимодействиями, обусловленными эффектом Рамана [2] и плазмонными эффектами [3]. Недавние разработки в области спектроскопии гигантского комбинационного рассеяния позволили значительно повысить чувствительность измерений и обнаружить новые явления [4,5]. Также поверхностно усиленное ИК поглощение (SEIRA), открытое в 1980 г.…”