Infrared spectroscopy, known for its effectiveness in the quantitative and qualitative analysis of molecules and materials, has been extensively employed across multiple industries for years.^1,2

Its ability to sensitively detect the frequencies of chemical bonds has made it a very powerful tool for the analysis of different species, including heterogeneous bioorganic molecules and materials. However, more recent developments in infrared absorption nanoimaging and atomic force microscopy infrared (AFM-IR) have revolutionized the technique, transforming it into a method with the high spatial resolution of AFM but with the chemical identification capabilities of infrared spectroscopy.³

Image Credit: Ken stocker/Shutterstock.com

One of the key breakthroughs in AFM-IR was the development of instrumentation with sufficiently high signal-to-noise that a single protein molecule could be detected with off-resonant, lower power, and short pulses (ORS-nanoIR).⁵ Many protein disorders are caused by the incorrect folding of proteins; thus, the protein structure can be used both as a diagnostic tool and as a template and inspiration for the development of therapeutics. In particular, ORS-nanoIR is sensitive to the secondary structure of proteins, which is important for predicting higher orders of structure and identifying polypeptide sequences and their structures, which strongly influence protein folding behavior.

Considering its omnipresence across the industry, Instrumentation and Nanoscience has been selected as one of the main tracks at this year’s Pittcon. Over five eventful days, Pittcon 2024 will be host to thought leaders in this field, offering insights into the latest developments and applications. This article will delve into these topics further, highlighting the significance and potential of these groundbreaking techniques.

Drug Design and Surface Science

One key application of AFM-IR is identifying the interaction fingerprint between small molecules and their targets or surface behaviors.⁶ These molecule-target interactions are crucial in determining the effectiveness of therapeutics, making such studies vital for new drug development and understanding the roles of proteins in diseases.

AFM-IR is also being used as a surface-sensitive technique for a variety of functional materials, including model membranes, protein self-assemblies, and perovskites.⁷ The technique’s nanoscale imaging resolution is critical for assessing the functionality of these materials and identifying which nanoscale structures yield optimal properties. For instance, in the case of perovskites, efficient light absorption is a crucial factor for photovoltaic applications. For halide-perovskites, AFM-IR has been used to map the distribution of the halides in the perovskite material, which can be challenging to do with many techniques, but as AFM-IR can be performed at a number of wavelengths, area maps can be constructed to contrast halide-rich and poor areas in the image.⁷

At Pittcon 2024, an entire session will be dedicated to developments in nanoscale IR spectroscopy. This session⁸ will explore key techniques such as AFM-IR as well as related methods like enhanced Raman approaches. One of the key speakers will be Professor Francesco Simone Ruggeri, who has pioneered the development of nanoscale imaging techniques to the single molecule level for the characterization of both biomolecules and advanced materials. In particular, his group has been focusing on the molecular processes associated with protein folding and other processes and how they can malfunction in the case of neurodegenerative diseases.

The team has made a number of breakthroughs in the application of nanoscale imaging techniques to study problems such as the interactions between an aggregation inhibitor with amyloid proteins, which is one possible approach to the development of therapeutics for diseases such as Parkinson's and Alzheimer's.⁹

This session is set to offer new insight into the latest applications of infrared-based nanoscale imaging in the field of biomedical research, providing enhanced insights into protein structures and their significant implications for treating complex diseases.

Related Methods

There are also a number of related techniques that can be combined to offer more powerful and detailed analyses, such as electrochemical tip-enhanced Raman spectroscopy (EC-TERS) and electrochemical surface-enhanced Raman spectroscopy (EC-SERS). Both of these methods employ enhancement techniques to amplify weak Raman signals, thereby improving spectral acquisition times.

A new approach, called EC-Tip-SERS, combines surface and tip enhancement effects to generate even larger Raman signals for measurement to boost the sensitivity of the technique.¹⁰ This combination is particularly valuable for monitoring electrochemical processes, as it allows for selective interface probing in cells. However, challenges arise when electrolytes are not used with the necessary plasmonic materials, and achieving high spatial resolution can be difficult when numerous Raman active species are in close proximity, causing their signals to overlap.

Overall, Raman spectroscopy and its many variants are being used in a large number of fields and are highly interdisciplinary techniques. Enhancement methods, like EC-TERS, are incredibly important developments in pushing Raman spectroscopy for the detection of single molecules and low concentrations of species, meaning the quantitative and qualitative analysis powers of Raman spectroscopy can be unlocked for studying a greater number of scientific problems.

In a session titled ‘Enhanced Raman Approaches for Understanding Electrochemical Reactivity: Temporal and Spatial Resolution,’ ¹¹ Emmanuel Maisonhaute will introduce the new method, EC-Tip-SERS, presenting some of the latest developments in that direction.

An Industry Focus

In addition to experts across the sector, Pittcon will also be host to longtime leaders in electron microscopy, such as Hamamatsu and JEOL USA. Hamamatsu has a renowned reputation for high-sensitivity infrared detectors, and JEOL USA excels in the production of high-quality electron microscopy infrastructure—both of which are key factors in the development of successful instrumentation.

This fusion of cutting-edge microscopy and sensitive detection technologies is key to achieving the effectiveness and reliability associated with AFM-IR techniques. Company representatives will be on hand at the exposition, exhibiting some of the most recent developments in instrumentation and providing answers to any inquiries you might have.

Instrumentation & Nanoscience at Pittcon

This year’s events are scheduled to begin at 8:30 a.m. on February 24^th, serving as a platform for showcasing significant scientific breakthroughs. Pittcon 2024 will feature a dedicated track on Instrumentation & Nanoscience, offering a variety of sessions on the subject tailored for everyone from researchers to the general public. In addition to the main presentations, the event will also include various short courses and interactive sessions.

To register or preview the upcoming talks, sessions, and short courses, you can visit the Pittcon website.¹² There, the Session Gallery provides an overview of the events planned for the week.

References and Further Reading

1. Rohman, A., Windarsih, A., Lukitaningsih, E., Rafi, M., Betania, K., & Fadzillah, N. A. (2019). The use of FTIR and Raman spectroscopy in combination with chemometrics for analysis of biomolecules in biomedical fluids: A review. Biomedical Spectroscopy and Imaging, 8(3–4), 55–71. https://doi.org/10.3233/bsi-200189
2. Bakeev, K. A. (Ed.). (2010). Process analytical technology: spectroscopic tools and implementation strategies for the chemical and pharmaceutical industries. John Wiley & Sons.
3. Dazzi, A., & Prater, C. B. (2017). AFM-IR: Technology and applications in nanoscale infrared spectroscopy and chemical imaging. Chemical Reviews, 117(7), 5146–5173. https://doi.org/10.1021/acs.chemrev.6b00448
4. V. D. dos Santos, A. C., Hondl, N., Ramos-Garcia, V., Kuligowski, J., Lendl, B., & Ramer, G. (2023). AFM-IR for Nanoscale Chemical Characterization in Life Sciences: Recent Developments and Future Directions. ACS Measurement Science Au. https://doi.org/10.1021/acsmeasuresciau.3c00010
5. Ruggeri, F. S., Mannini, B., Schmid, R., Vendruscolo, M., & Knowles, T. P. J. (2020). Single molecule secondary structure determination of proteins through infrared absorption nanospectroscopy. Nature Communications, 11(1), 1–9. https://doi.org/10.1038/s41467-020-16728-1
6. Zhang, J., Khanal, D., & Banaszak Holl, M. M. (2023). Applications of AFM-IR for drug delivery vector characterization: infrared, thermal, and mechanical characterization at the nanoscale. Advanced Drug Delivery Reviews, 192, 114646. https://doi.org/10.1016/j.addr.2022.114646
7. Gross, E. (2019). Challenges and opportunities in IR nanospectroscopy measurements of energy materials. Nano Research, 12(9), 2200–2210. https://doi.org/10.1007/s12274-019-2402-z
8. Nano-chemical Imaging and Spectroscopy towards the Single-molecule Level Attend networking events and meet the right people with the LabSci by Pittcon event app. Available at: https://labscievents.pittcon.org/event/pittcon-2024/planning/UGxhbm5pbmdfMTY2NzkwNw== (Accessed: 12 December 2023).
9. Ruggeri, F. S., Habchi, J., Chia, S., Horne, R. I., Vendruscolo, M., & Knowles, T. P. J. (2021). Infrared nanospectroscopy reveals the molecular interaction fingerprint of an aggregation inhibitor with single Aβ42 oligomers. Nature Communications, 12(1). https://doi.org/10.1038/s41467-020-20782-0
10. Zeng, Z. C., Huang, S. C., Wu, D. Y., Meng, L. Y., Li, M. H., Huang, T. X., Zhong, J. H., Wang, X., Yang, Z. L., & Ren, B. (2015). Electrochemical Tip-Enhanced Raman Spectroscopy. Journal of the American Chemical Society, 137(37), 11928–11931. https://doi.org/10.1021/jacs.5b08143
11. Enhanced Raman approaches for understanding electrochemical reactivity: temporal and spatial resolution. (no date) Attend networking events and meet the right people with the LabSci by Pittcon event app. Available at: https://labscievents.pittcon.org/event/pittcon-2024/planning/UGxhbm5pbmdfMTY2ODAyNg== (Accessed: 12 December 2023).
12. Home (2023) Pittcon Conference + Expo. Available at: https://pittcon.org/ (Accessed: 12 December 2023).

This information has been sourced, reviewed, and adapted from materials provided by Pittcon.

For more information on this source, please visit Pittcon.