Bioimaging: An Industry guide to Clinical Spectroscopy

Introduction

As biomedical research focused on personalized therapy continues to grow, molecular spectroscopy also continues to expand, with the hope that this growth will contribute to the development of new diagnostics and novel therapies for hard-to-treat diseases.

This will be especially discussed during Professor Jeremy Nicholson’s Wallace H. Coulter lecture at Pittcon 2018. Here, Prof Nicholson will describe his passion to achieve more efficient and effective healthcare solutions in the 21st century by using analytical science in precision medicine.

Pittcon 2018 are also pleased to announce that Dr Stefan Hell, Director at the Max Planck Institute for Biophysical Chemistry in Göttingen and Director at the Max Planck Institute for Medical Research in Heidelberg, will be presenting this year’s plenary lecture – “Optical Microscopy: The Resolution Revolution”. In this talk, Dr Hell will discuss how to overcome the resolution-limiting role of diffraction in order to image living cells and tissues at the nanoscale.

Molecular Spectrometry and Its Insight into Human Disease

Human proteins play integral roles in cellular processes involved in health, and gaining insight into the proteins’ presence, structure, function, and variance is essential for understanding disease. Subsequently, the direct insight gained with imaging spectrometry plays an indirect role in advancing the state of patient care via developing targeted therapies that improve quality of life and survival.

Proteomic research involving imaging mass spectrometry is aimed at helping to identify gene expression and complexity while allowing for identification of proteoforms produced by post-translational functions. Measurement of proteomes shows potential for translational applications, considering that most normal and modified cellular processes depend upon protein expression and regulation.

Professor Xiaowei Zhuang of Harvard, awardee of the Pittsburgh Analytical Chemistry Award Symposium, will be discussing the level at which we are now able to study biology using bioimaging techniques, in his presentation titled “Illuminating Biology at the Nanoscale and Systems Scale by Imaging”.

In biomedical clinical research, measurements using broad quantitative imaging mass spectrometry can help identify peptides and proteins that vary in number among patients receiving either intervention or control. A benefit of this strategy is the unbiased ability to identify and characterize an entire proteome in one measurement. Additionally, tandem mass spectrometry may be helpful for obtaining additional information about unknown peptides in bottom-up mass spectrometry biomedical studies.

Unfortunately, many challenges exist with current spectroscopy applications, including isomeric indistinguishability and inadequate throughput of measurements. Additionally, some tissue analytical techniques can take considerable time spent in the lab, especially when investigators are performing multi-target monitoring of samples. Also, due to the extensive number of extractions necessary for capturing small molecules in complex environments and biofluid samples, a need exists for analytical sampling techniques that can be rapidly performed without sacrificing quality of molecule characterization and quantification.

At Pittcon in Orlando, Florida, February 26-March 1, 2018, numerous talks and exhibitions will be given on the latest biomedical analytical spectroscopy techniques available for cancer as well as other specific biomedical identification strategies. This article will discuss some of the speakers and company exhibitors, and how their latest technologies have created new solutions to some of the greatest spectroscopy challenges commonly experienced in the lab.

Pittcon Tracks

Bioanalytical & Life Science
Biological molecules and xenobiotics (drugs, toxins) and their metabolites; study of biological systems; biosensors; forensic science and toxicology
Cannabis & Psychedelic
Identification, quantitative measurement, extraction, and quality assurance of cannabis-based and psychedelic products
Environment & Energy
Environmental detection and monitoring; energy production and storage; sustainability, climate, and green chemistry; food science/safety and agriculture
Instrumentation & Nanoscience
Instrumentation, detection, and sensors; laboratory information systems, data analysis, and artificial intelligence; characterization and processing of nanomaterials; art and archeology
Pharmaceutical & Biologic
Evaluating chemical composition and properties/activities of medicinal drugs and biologics; high-throughput screening and process control; drug discovery and design; personal care and consumer products
Professional Development
Leadership and power/soft skills; career navigation, DEI (diversity, equity and inclusion), communication, and entrepreneurship; education and teaching and more

Chapter 1 – Spectroscopy in the Biomedical Industry

The use of molecular spectroscopy in the biomedical industry has expanded in recent years, partially driven by the emergence of low-cost, compact, and portable systems that have enabled faster and greater depth in molecular analyses. Investigators are currently using spectrometers in biomedical research to examine antioxidants, carcinogenic tumors, the pathways involved in cardiovascular disease, bone tissue, compounds associated with neurological deficits, and viruses.

As medical research focused on personalized therapy continues to grow in relation to the evolutionary speed of analytical technology, molecular spectroscopy will expand and may contribute to the development of new therapies for numerous hard-to-treat diseases.

Raman Spectroscopy

In Raman spectroscopy, both structural and chemical data of a studied substance are provided to help researchers obtain greater detail about the analyzed material. Using this strategy, investigators are able to detect and identify unknown compounds from unique Raman spectra fingerprints.

At Pittcon 2018, Paul Champion will be discussing a study which describes the use of Raman spectroscopy for the study of hemoglobin and the related vibrational mode-specific relaxation processes directly following photoexcitation. Additionally, Champion will discuss the role of the time-dependent line shape function for extracting mode-specific vibrational temperatures from Raman resonance data. This talk will also highlight the main factors involved in temperature dependence of resonance Raman scattering.

Also at Pittcon 2018, X Sunney Xie, one of the worlds foremost figure in Raman, will be presenting a talk titled “Single Cell Genomics: When Stochasticity Meets Precision”, as part of the Pittsburgh Analytical Chemisty Award Symposium.

Many Raman imaging systems, like the RA802 Pharmaceutical Analyser by Renishaw, are compact benchtop instruments that are used primarily for analyses in the clinical space.

Raman instruments with a high spectral resolution across the Raman range provides greater chemical specificity, therefore facilitating enhanced differentiation between numerous compounds and materials. Typically, investigators comparing materials to their Raman spectra may ultimately have the ability to differentiate materials of similar polymorphic forms derived from the same chemical. Promising research areas for applying the Raman approach include cell biology, pharmacology, and tissue engineering. Some Raman microscopes, like the DXR Raman microscope offered by ThermoFisher Scientific, are able to provide 2-micron depth resolution and a high level of sensitivity and repeatability for medical use. Both Renishaw and Thermo Fisher will be available at Pittcon 2018 to talk about their Raman technology.

In addition, using Raman spectroscopy allows analyzation of changes in various spectrum details, such as the position, width, and height of Raman bands. This enables researchers to identify the proportion of material, layer thickness, temperature, and variation in stress state or crystallinity.

The portability, compactness, and high-resolution of handheld systems may help improve efficiency in obtaining direct findings of materials. B&W Tek, another exhibitor at Pittcon 2018, provides handheld and portable Raman spectrometers, such as the NanoRam® and i-Raman®, with accompanying analytical software suited for operators at multiple levels of technological experience.

Imaging Mass Spectrometry

Imaging mass spectrometry is a relatively new spectroscopy approach which offers in-depth observation, monitoring, and detection of molecular processes within the tissue spatial domains. Thus, the use of this technology has practical benefits in both biology and medical research. Imaging mass spectrometry quantifies tissue molecules without having to rely on target-specific antibodies or other reagents.

Richard Caprioli will be discussing the application of mass spectrometry in the study of biology and medicine at Pittcon 2018. Specifically, Caprioli will highlight the utility of using imaging mass spectrometry for detecting and monitoring molecular processes found in tissues’ spatial domains for medical and biological study and will describe how recent advances in sample preparation and instrument performance have enabled higher spatial resolution imaging (1-10 microns) at higher speeds. Additionally, the talk will discuss the use of the Bruker 15T solariX FTICR MS for small animal research, particularly as it pertains to imaging tissues for potential identification of compounds associated with disease.

This technology directly measures molecular compounds in tissues without the use of target-specific reagents such as antibodies, is applicable to a wide variety of analytes, and can provide spatial resolutions below the single cell level.

Also, imaging mass spectrometry can be applied to several different types of analytes. Ionization methods used in imaging spectroscopy applications include matrix assisted laser desorption/ionization (MALDI), desorption electrospray ionization (DESI), and Fourier-transform ion cyclotron resonance (FTICR). According to the literature, MALDI imaging mass spectrometry is perhaps the most applicable and effective for imaging biological and medical samples.

MALDI

MALDI offers the ability to directly monitor lipids, proteins, peptides, and metabolites found in tissues. The MALDI Biotyper from Bruker represents one of the MALDI imaging systems which aid in the taxonomical classification of yeasts, bacteria, and fungi through fingerprinting methods. This Bruker system is one of the many spectroscopy instruments Bruker will be showcasing at Pittcon 2018.

Ion Mobility Spectrometry

The use of ion mobility spectrometry is an additional analytical technique used in clinical research for the separation and characterization of ionized molecules found in the gas phase. Overall, ion mobility spectrometry can enhance workflows for imaging mass spectrometry and improve efficiency of studies which require evaluation of specific molecules.

At Pittcon 2018, Erin Baker will provide an overview on the study of biofluids as well as environmental samples using an automated solid phase extraction method before ion mobility spectrometry. Using this method, researchers may minimize ionization suppression, detect exogenous and endogenous metabolites, and remove salts more efficiently. In addition, Baker will discuss how ion mobility separations as well as mass spectrometry may improve isomeric distinguishability by providing high throughput analyses.

Bruker’s RAID instruments are ion-specific spectrometry tools that may offer utility for some clinical applications. Additionally, the SYNAPT and Vion instruments from Waters offer ion mobility separations necessary for a range of study types, including for the biomedical field.

References


Chapter 2 – Molecules and Materials in Bioimaging and Biomonitoring

Bioimaging of enzymes, nanoparticles, and cells may play an integral role in the development of new, more effective, and targeted therapies for disease. At Pittcon 2018, investigators in the field of bioimaging will be presenting their cutting-edge research, highlighting the advantages of using various bioimaging modalities for improving disease identification and patient care.

Imaging Molecules

Direct imaging of molecules, specifically metals, features important relevance to biological research. Numerous metals are essential for life, often playing roles in protein synthesis and the transcription and translation of nucleic acids. Gaining a deeper understanding of how these metals work in the body relies on high-quality bioimaging analysis. Fluorescent probes, for example, are often used for the detection, identification, and study of transition metals and their signaling actions in biological systems.

At this year’s Pittcon, Christopher Chang of the University of California, Berkeley, will be presenting key research on activity-based sensing (ABS) strategies for interpreting signaling of transition metals. A focal point of his research—ABS—is centered primarily on using chemical reactivity in lieu of standard “lock-and-key molecular recognition” for modifying biological molecules and systems.

In his presentation, Chang will demonstrate how an ABS approach can be used to discover new chemical signals in sulfur, carbon species, reactive oxygen, and transition metals. The findings of his research is aimed at helping other researchers in uncovering the biological functions of a variety of molecules.

Imaging Nanoparticles

Observations of natural phenomenon has helped researchers understand how nanoparticles can be modified to produce complex intracellular structures featuring diverse biological functions. One study, using in vivo whole animal and ex vivo super resolution fluorescence imaging, examined the construction of nanostructures from nanoparticles in tumors under enzyme control.

Considering that enzymes play pivotal roles in catalyzing numerous biological reactions within the body, imaging research of how enzymes and nanoparticles interact in cancer represents an important step for understanding carcinoma development and progression. Additional research has examined the use of nanoparticles as acting as enzyme-directed morphological transformations in response to specific stimuli, notably targeted therapies. The investigators of this research suggest that modification of nanoparticle responses to disease-related enzymes may provide clinical utility for therapeutic delivery as well as disease detection.

Liquid Cell TEM

Recently, there has been a surge of interest in liquid cell transmission electron microscopy (TEM) for imaging seemingly invisible materials through liquids. Liquid cell TEM facilitates in situ imaging of precipitation using high-quality spatial resolution and has been applied to physics, chemistry, and materials science research. Recent studies have utilized liquid cell TEM for evaluating the growth, arrangement, tracking, and manipulation of nanoparticles.

There has been a growth of interest in using nanomaterials as medical and diagnostic carriers in a variety of disease states. Typically, nanoparticles are the most heavily used nanomaterials in biological study as they are small enough to be injected directly into the bloodstream while still being large enough to act as effective targeted carriers.

Imaging these nanoparticles and the therapies they carry is an essential step in understanding targeted therapy, which may ultimately translate into improved medical care for individuals with a myriad of health issues. Microspectroscopy systems, such as the Thermo Scientific™ Nicolet™ or Thermo Scientific™ DXR™ systems are an excellent candidate for nanoparticle research. Additionally, these imaging platforms hold utility for detecting unknown materials via a single point measurement and/or spatial spectroscopy.

During Pittcon 2018, Nathan Gianneschi of Northeastern University will present research regarding the use of a multimodal imaging platform for use in the study of targeted therapeutics and molecular diagnostics.

Specifically, Gianneschi and colleagues will explain how they went about preparing highly functionalized polymer scaffolds and their subsequent production of these scaffolds as in vivo probes. In targeted therapy, the goal is to gather drugs or probes at the disease site in substantial quantities “relative to other locations in the body.” An important area of Gianneschi et al’s research is the utility of in vivo probes as an imaging platform as well as drug carriers in targeted therapy.

Physical Imaging

In a talk at Pittcon 2018, Cesar Castro of the Massachusetts General Hospital will describe his research regarding the utility of smartphone technology for the rapid identification of cancer using marker-specific microbeads. In his talk “Highlighting Cancers Through Shadows and Smartphones,” Castro will also explain how he and his colleagues produced a 2-step labeling system that can streamline preparation of reagents via removal of antibody modification.

Castro will discuss the development of the Digital Diffraction Diagnosis System (D3) device, which attaches to a smartphone. Simply, the device offers an imaging module and LED light which produces and records high-resolution pictures using the camera from the individual’s mobile phone. Overall, the D3 device has a larger field of view than standard microscopy systems and can record data on >100,000 cells using a prick of blood or tissue sample. The preliminary data presented by Castro demonstrates higher diagnostic accuracy than some other tests currently being offered.

During his talk, Castro will also discuss the importance of smartphone technology in cancer screening and care in rural or resource-limited communities. The synergistic role of future technology with holographic approaches, such as wearable sensors and deep learning, will also be discussed as it relates to medical care.

References


Chapter 3 – Bioanalytical techniques in diagnostics

Numerous bioanalytical techniques have been introduced in recent years for the identification of analytes as well as for diagnostic purposes. Due to the high sensitivity of detection, it is recently common to see Raman molecular imaging being developed for clinical uses, such as for endoscopy and in intraoperative imaging for the guidance of surgical resection. At Pittcon 2018, researchers experienced in Raman spectroscopy and diffuse resonance Raman spectroscopy (DRRS) will be discussing how they use these platforms for a variety of diagnostic and quantitative analyses.

Raman Spectroscopy for the Clinical Field

Raman spectroscopy holds important value or the biomedical space, with applications ranging from in vitro biofluid assays and pharmaceutical study to breast cancer diagnosis based on chemical composition. One study has shown that Raman spectroscopy may even be helpful for the rapid identification of ricin, a naturally derived toxin that can produce potential harm and even death to exposed individuals. Thus, Raman spectroscopy has the potential to save lives if used early.

Richard Dluhy, PhD, from the University of Alabama at Birmingham, will be presenting a talk at Pittcon 2018 on the utilization of Raman spectroscopy for the biochemical characterization of stored red blood cells (RBCs) used for transfusion. In his talk, Dr. Dluhy will outline how Raman spectroscopy can streamline the process of assessing RBCs for quality prior to transfusion, thus avoiding the often time-consuming process associated with standard methods. Doing so, according to Dr. Dluhy, may ultimately improve therapeutic efficacy and reduce transfusion-related toxicity. In addition, Dr. Dluhy will discuss a recent study which aimed to develop DRRS for rapidly obtaining depth-sensitive Raman spectra for RBC screening.

The Role of DRRS

At Pittcon 2018, DRRS will be another topic introduced, and researchers will discuss its application to a variety of scientific fields. The use of DRRS in bioanalytical techniques is important for researchers wishing to obtain depth-sensitive Raman spectra in a timely and less-invasive manner compared with typical strategies. Contrary to excitation via near-infrared wavelengths, the use of DRRS requires up to 10-fold less power and time for acquiring a similar signal-to-noise ratio.

Instead of using a focused beam, DRRS relies on illumination via a diffuse beam, thereby decreasing photon density and providing greater penetration of the sample. In an effort to augment detection of diffuse photons, DRRS includes additional pixels from a charged coupled device detector that align with the pixels in the optical line of the micro-spectrometer.

Some research suggests that DRRS amplified by surface-enhanced Raman scattering nanoparticles may provide high sensitivity and rapid acquisition time for in vivo and in situ detection of heme proteins, carotenoids, and multiplexed nanoparticles. Additionally, DRRS may enable mapping of a larger sample area in small animal models than other commonly used microscopy platforms.

ThermoFisher’s DXR2 and DXR2xi Raman imaging microscopes, for example, are helpful for analytical experiments measuring multi-layer composites while providing real-time on-screen data acquisition. Renishaw’s RA802 Pharmaceutical Analyser, a benchtop Raman imaging system, provides API/excipient domain statistics and analyzation of sample preparation specifically for pharmaceutical study and development. Horiba’s XploRA ONE™ and LabRAM, which provides advanced confocal 2D and 3D imaging for micro and macro measurements, represents some of the additional available DRRS solutions for the pharma and biomedical fields.

References


Chapter 4 – The Future of Clinical Tissue Analysis

The use of live Raman imaging strategies continues to play a central role in the drug discovery process as well as the biomedical analysis of in vitro and in vivo tissue samples. Advanced Raman scattering modalities, such as stimulated Raman scattering microscopy (SRSM), has facilitated faster detection and imaging analyses in biomedical research. Using SRSM, a tool highlighted at Pittcon 2018, researchers can generate real-time, three-dimensional imaging of tissue samples with a greater degree of sensitivity and specificity than conventional imaging tools.

Emerging Raman Spectroscopy Modalities for Tissue Analysis

Although today’s researchers have an armamentarium of tools at their disposal analyzing for tissues in their native environment, certain challenges still exist with these modalities. Vibrational spectroscopies, such as Raman spectroscopy, may provide greater potential than conventional fluorescence microscopy for label-free visualization of biological structures. For live cell imaging, Raman spectroscopy is perhaps the most suitable analytical tool. With Raman spectroscopy, one fixed laser wavelength is used to create inelastic scattering of the vibrational Raman active modes within the analyzed sample.

SRSM

Raman scattering, a non-destructive and non-invasive technique, uses low-energy laser irradiation. In the quantum particle interpretation of Raman scattering, light (photon) comes into direct contact with the molecule and scatters. Signals of SRSM are produced via the alignment of the pump and Stokes beams. Investigators are able to achieve three-dimensional imaging of a sample by raster scanning the laser focus and moving this focus into the studied sample.

SRSM is a type of nonlinear Raman imaging that holds promising utility in biomedical analysis. Compared with spontaneous Raman spectroscopy, which is prone to poor resolution, slow data acquisition, and sensitivity issues, SRSM provides faster data acquisition rates and greater sensitivity for analysis. Using SRSM, researchers are able to achieve the same quality of traditional Raman microscopy imaging without the limitations associated with speed and spatial resolution. This emerging imaging application enables biomedical researchers to investigate specific molecular vibrational modes and may help in the engineering of human tissue.

A presenter at Pittcon 2018, Rohit Bhargava of the University of Illinois at Urbana-Champaign, will discuss high-resolution tissue imaging using SRSM. During this talk, Dr. Bhargava will present specific examples of SRSM applications for the categorization and identification of tissues found in patients with prostate cancer. Also, he will provide an overview of how SRSM can be used to provide high-quality monitoring of the changes found in epithelial tumor cells during prostate cancer analysis.

Zev Gartner, associate professor in the Department of Pharmaceutical Chemistry at the University of California-San Francisco, will also provide an overview of his lab team’s efforts in building in vivo-like human tissues with the utilization of new technological advancements in tissue imaging and engineering at Pittcon 2018. During his talk, Dr. Gartner will discuss the application of engineered tissues in medicine and drug screening, the factors associated with human tissues’ underlying mechanisms of self-organization, and will also highlight the key challenges and solutions for building three-dimensional tissue structures for biomedical applications. One of the solutions for engineering these human-like tissues that will be emphasized during the event is the use of Raman spectroscopy.

Overall, SRSM imaging can be produced from various tissue environments, providing high-quality resolution that can be applied in preclinical study applications. Additionally, SRSM can be used in the analysis of cellular drug distribution throughout cells and tissue. Another application of SRSM is for the evaluation and mapping of in vivo lipid oxidation and cholesterol storage, thereby helping researchers identify early predictors of disease (eg, atherosclerosis and diabetes) as well as aid in the development of novel therapies.

References

  • Gartner ZJ, Bertozzi CR. Programmed assembly of 3-dimensional microtissues with defined cellular connectivity. Proc Natl Acad Sci U S A. 2009;106(12):4606-4610
  • Liu JS, Farlow JT, Paulson AK, Labarge MA, Gartner ZJ. Programmed cell-to-cell variability in Ras activity triggers emergent behaviors during mammary epithelial morphogenesis. Cell Rep. 2012;2(5):1461-1470
  • Tipping WJ, Lee M, Serrels A, Brunton VG, Hulme AN. Stimulated Raman scattering microscopy: an emerging tool for drug discovery. Chem Soc Rev. 2016;45(8):2075-2089
  • BW TEK. Theory of Raman Scattering. http://bwtek.com/raman-theory-of-raman-scattering/
  • Ozeki Y, Umemura W, Otsuka Y, et al. High-speed molecular spectral imaging of tissue with stimulated Raman scattering. Nature Photonics. 2012;6:845-851

Conclusion

Spectroscopy is an imaging modality that has wide-reaching applications in biomedical research and clinical practice. Biomedical spectroscopy can assist research studies aimed toward examining and engineering new tissue structures for patients with limiting diseases or disorders.

Previous challenges with spectroscopy applications were often associated with resolution, data acquisition time, and throughput limitations. Modalities such as matrix-assisted laser desorption/ionization imaging (MALDI) can be challenging when trying to identify protein biomarkers in complex solutions. Despite this challenge, standardization protocols as well as technological advancements in MALDI platforms have provided practical solutions for researchers. Recent advancements in Raman vibrational coherence spectroscopy and ion mobility spectroscopy techniques have also facilitated greater and more rapid discovery capabilities in biomedical research.

At Pittcon 2018, Bruker, Waters, Thermo Fisher Scientific, Gerstel, Horiba, Lumex etc will present their latest bioanalytical technologies, all of which have been engineered to reduce time in the lab while improving the quality of molecule identification. Each exhibitor will be on hand to discuss their latest technology, the research behind it, and the many applications these tools have in the clinical environment. Technologies such as Raman spectrometers for biomedical analyses, microspectrometers for nanoparticle bioimaging and biomonitoring for bioanalytical diagnostics will be presented at Pittcon 2018.

Advancements in spectroscopy technology have enabled researchers to identify and characterize molecules of all sizes and weights using relatively simple, low-cost strategies. Several speakers from various biomedical research fields will be in attendance at Pittcon 2018 and will be discussing how they utilize this new technology in the field of cancer diagnostics, drug assays, and more.