1.1

Raman for Life

The Perseverance Rover is the 5th rover that NASA has sent to Mars, landing and commencing its mission in February 2021, to much public acclaim.²⁵ Onboard are an array of 7 instruments designed to perform unprecedented scientific experiments on the surface of Mars, one of which is a UV Raman spectrometer built into SHERLOC (Scanning Habitable Environments with Raman and Luminescence for Organics and Chemicals)²⁶. Raman spectroscopy plays a key role in this mission due to its capability to identify molecules and materials. The Perseverance Rover and other such efforts for interplanetary research are a topic widely covered in the media and hold a strong presence and recall with children and youth. This is due to its interdisciplinary origins, its ground-breaking research and fascination with the unknown, and the potential for the discovery of life on other planets. Recent media coverage of The Perseverance Rover spread widely across the modern world due to social media influences and cultural impact, making it a “hot topic” in both the scientific community and public interest ²⁷ It thus offers a particularly suitable vehicle through which the underpinning “real science” behind the rover and its mission may be conveyed in a digestible way to the public. This provided the impetus and contextual groundwork for development of the R4L Rover, a remote-operated model version of the perseverance Mars rover, with a functional and demonstrable Raman spectrometer on board.

Among other areas Raman spectroscopy is being especially used in medical research with applications ranging from disease diagnosis²⁸ to characterising bacterial pathogens²⁹ to the development of novel drugs. Chemometric information provided by Raman spectroscopy affords rich information about biological material at the cellular and tissue scale, perfectly suited for medical applications. With minimal requirements for sample preparation to carry out characterisation, these technologies are conducive for in vivo and/or label-free applications^30,31. Raman active bonds associated with biological moieties such as lipids and proteins have been utilised for label free, microscopy of tissues using the so-called technique of Coherent Anti-Stokes Raman Scattering (CARS)³². A repertoire of techniques based on Raman technologies have facilitated a wide range of clinical analysis for highly efficient signal measurements (SERS)³³, interrogation at depth (SORS)³⁴, and so on. The prominence and relevance of such applications will motivate the public’s education of Raman spectroscopic technologies. Under the overarching theme of “Raman For Life” a device referred to as “Dr Raman” was developed to showcase the capacity and efficacy of Raman spectroscopy for characterising biological samples. Here a functional small footprint portable Raman spectrometer was demonstrated to be able to identify between models of simple cellular structures, indistinguishable by eye. This served to convey, in an accessible way, the role Raman spectroscopy is poised to play in clinical and life science research.

1.2

Raman Spectroscopy

Raman Spectroscopy is an optical technique that probes the molecular structure of a sample by interacting with the vibrational modes of its constituent chemical structure.^{35 36} This is facilitated by spontaneous Raman scattering, an inelastic interaction between light and the target material. The statistically dominant interaction between an incident photon and molecules of a certain dimension is defined by elastic Rayleigh scattering, which sees no change in photon energy before and after the interaction (Figure 1). However, in spontaneous Raman scattering there is a frequency shift between the incident and emitted photon equal to the energy associated with a molecular vibration. If the emitted photon has a lower frequency, this is known as a Stokes shift, caused by a transfer of energy to the molecular vibration. In an anti-Stokes shift, the molecule exists initially in an excited vibrational state, and during the interaction transfers energy to the photon, observed as an increase in frequency of the exiting photon. ³² Shifts in frequency are characteristic of molecular vibrations (bonds or phonons) and as such collecting a spectrum of these interactions allows a chemical “fingerprint” to be obtained for the sample being examined.

Figure 1:

Raman Vs Rayleigh Scattering Diagrams. On the left we have the two forms of Raman Scattering: Stokes and Anti-Stokes and on the right, we have the energy transition for Rayleigh Scattering

To produce a Raman spectrum of a material a sample is excited using a laser, able to produce many photon interactions, which is necessary as the nature of spontaneous Raman spectroscopy is statistically dependant on the number of interactions.³⁷ This will interact with all the different molecules within the material simultaneously, when an interaction matches a vibrational state within the molecule, photons at a shifted wavelength are observed. To detect these, scattered light is passed through a Rayleigh filter that removes the photons at the laser wavelength in a spectrometer. In the spectrometer the light further passes through a diffraction grating and is separated depending on its wavelength.³⁸ After the light is split it can be spread across a detector, which allows us to see which of scattered wavelengths have the highest intensity. The wavelengths that are detected with the highest peak intensity will relate to the most common vibrational modes within the molecule, which reveals information about its molecular structure. Raman spectral intensities are most commonly plotted against wavenumber (cm^-1) as it scales linearly with Energy.³⁶ Figure 2 shows an example of a Raman spectrum of Ethanol, which shows different peak intensities at different wavenumbers. From these peaks we can deduce certain information about the material, for example we call the region between 2800 – 3200 cm^-1 the high frequency region as it’s caused by the different vibrational modes of the C-H bonds in Ethanol.³⁹ The spectral region between 200 – 2000 cm^-1 is often referred to as the fingerprint region. There is a large store of spectral information that can be compared to analyse the chemical structure of a material.³⁶ Raman Spectroscopy is the technique of focus in this outreach project.

Figure 2:

Raman Spectrum of Ethanol: John Wiley & Sons, Inc. SpectraBase; SpectraBase Compound ID = Kn46yonbl3b SpectraBase Spectrum ID = 64WcXAR1x1s https://spectrabase.com/spectrum/64WcXAR1x1s (accessed 15/07/2022)

1.3

Activity Theme and Structure

An interactive narrative was developed to flow through the activities presented in the outreach event. Four activities were developed, each with learning objectives that developed and consolidated participants’ knowledge. The first two activities presented simple tasks to teach the base principles needed to understand Raman spectroscopy, referred to as “Acoustic Raman” and “Rainbow in a Box”. Acoustic Raman introduced the concept of molecular vibrations through the analogue of acoustic vibration, resonance effects through demonstrating the coherent amplification of sound, and observing vibrations to interpret the hidden contents of a material, an analogue for spectroscopic analysis. Rainbow in a Box introduced light-matter interactions and the spectroscopy concepts of light as a spectrum of intensities at observed wavelengths.

These introductory activities laid the groundwork for the Dr Raman and R4L activities, allowing introduction of increasingly complex topics, as well as highlighting the multidisciplinary applications of the technology. The story and thematic approach to this activity was that the participants were training to join a multi-disciplinary team of scientists, tasked with spectroscopic analysis on the surface of Mars. During this process a “training card” displayed the knowledge progression which encouraged the learning process for the more complex Dr Raman and R4L activities. Participants could take away the training card with them after completing all the stages. Thus, participants were able to exercise their development of knowledge from abstract concepts to application in multidisciplinary spheres, allowing career envisioning and recognising the interplay between various facets of STEM research. In developing a cohesive series of fun and engaging activities these would serve to improve the knowledge retention of all those involved.

2.1

Dr Raman

The theme of this stage of the demonstration is the clinical applications of Raman spectroscopy, by this stage the participants have learnt the basics of light interactions and the concept of resonance. Building on this we describe how those base principles come together in Raman spectroscopy and how the technique is then used in a clinical practice.

Dr Raman is an interactive medical simulation device that uses a working Raman spectrometer to display the Raman spectrum of “dummy” or model cells. These “dummy” cells are made of different polymer materials that give different Raman spectra. The participants were directed to change from sample to sample and determine which of the dummy cells are “sick” based on a pre-designed figure sheet. The key learning objectivises are that healthy and non-healthy cells will give distinct signals that allow us to diagnose diseases. This basic concept links the technology to a real world application.

2.1.1

Design

Dr Raman represents the clinical science aspect of Raman spectroscopy. Dr Raman was initially designed using computer aided design (CAD), with an initial structure as seen in figure 3a. A laser is incident on the target “cells” through an optical fibre from outside the case. A rotating plate allows for automatic rotation of the samples through the system. The light source illuminates the sample, and a secondary fibre feeds the detection signals to the spectrometer, via a targeting head. The system is controlled using a laptop that runs a set of commands to control the laser, detector, and the motion of the samples in the system. The signal is then processed and displayed on a screen for the participants to view as the samples are rotated.

Figure 3:

a) CAD design of Dr Raman created in Fusion 360, showing optical fibre placement, and moving platform. b) Photo of the internal wiring of the final version of Dr Raman. c) The display photo of Dr Raman with the laser illumination activated

2.2

Raman 4 Life Rover

The Raman for Life Rover (R4L) is a remote-controlled Mars Rover model based on the Perseverance Rover and previous Mars exploration devices. It had an approximate scale factor of ¼ the size of the real Rover and had a functioning Raman spectrometer with a built-in laser that allows it to take spectra remotely. It also has a functioning endoscopic camera for target location. The device was controlled with a game pad controller to allow people of all abilities to use the device.

This activity was designed to bring together all the previous learning objectives and convey how the same underpinning technology was developed for clinical science and interplanetary exploration. The participants were directed to guide R4L to a designated target, and when at the target the Rover would take a spectrum which would be processed and displayed on a screen. The participants would then be tasked with matching the spectra to those generated from standards and handed out on a set of premade sheets. During the demonstration we discussed the technology behind the Mars Rover, the model’s development and the science relating to Raman spectroscopy.

2.2.1

Design, 3D Printing and Construction

Initial designs were created by researching previous Rover designs and choosing what made the Rover look so specific. We decided to base the axle system on the rocker-bogie design that NASA (National Aeronautics and Space Administration) developed in 1988.^{40 41} A central body fixed at a single pivot point would use suspension to stay horizontal but allow the wheels to move independently while keeping the main body level. Finally, we wanted a head that could pivot in multiple angles to better position for spectra acquisition as this head would house the Raman spectrometer/laser device.

Initially we started to model individual components using Fusion 360⁴², each component would make up part of the overall structure. An initial design can be seen in figure 4 (a,b) in comparison to the constructed version in figure 4 (c) that shows how all the parts were gradually improved and redesigned as the construction of R4L began.

Figure 4:

a,b) Side and angled view of the 3D model of R4L in an early stage, the individual components were modelled separately and then combined in the software. c) A photo taken of the final version of R4L taken as part of the promotion for the event

Most of the components for R4L were printed using 3D printing technology using PLA (Polylactic acid) as the base material used in the Ender Pro 3.0⁴³ fused deposition modelling (FDM) printer⁴⁴ (creating the white components that can be seen in figure 4). A stereolithography (SLA) printer using a monomer that is polymerised layer-by-layer to produce the blue and clear components in figure 4.

The other main construction material was panelled poly(methyl methacrylate) (PMMA), that was used for the main side pieces as well as the long arm extensions. This was cut using a CO₂ laser cutter, with designs and sketches created using fusion 360. The axel was made using carbon fibre tubing to give it a great strength to weight ratio. Multiple prototype stages for each component led to the working model seen in figure 4.

2.3

Overall Activity Layout

Figure 5 shows how we set out the activity to best fit the theme. We wanted people to start at Acoustic Raman as part of their “basic training” stage, before moving onto Rainbow in a Box. Then they would move to “Medical training” with “Dr Raman”, before finally heading to the “R4L” zone and seeing the Rover in action. Supporting posters were displayed on boards behind the demonstrators to further help inform the participants, and handout versions were also available.

Figure 5:

Concept map for the layout of the activity, including the individual activities, display board placement, monitor placement and demonstration positions.

2.4

Supporting Activities

2.5

Evaluation and Feedback Method

To assess how the event engaged with the public we produced two feedback methods for participants to complete, after they had experienced all the demonstrations. The first was a formal feedback survey with a set of questions aimed at gauging how the participants enjoyed, but also what they learnt, from the event.

The first set of feedback was a survey that consisted of 7 questions, starting with basic information about the participant, gender, age, and their previous attendance at science festivals. The remainder of the questions covered topics such as: Which activity they did; What they liked the best; How relevant the topics were to their daily lives and Engagement ratings for each activity.

The second feedback method was qualitative written feedback, in which participants would stick responses onto a whiteboard below some prompts. The main prompt was “What did you learn about today?”, which had two subcategories relating to human health and space exploration. This method allowed people of all ages to fill out a response easily as well as giving us direct feedback on the day.

3.1

Southampton Science and Engineering Festival (SOTSEF 2022)

SOTSEF 2022 was on the 7^th of May at Highfield Campus at the University of Southampton, the event had many activities both from research groups within the university as well as outside organisations. Around 2000 people were registered as attending the event. The From Mars to Human event was placed in one of the main activity halls, we had approximately 400 people engage with the activity on the day, with many more viewing, or partially participating in some or most of the activities.

The volunteer demonstrators running and organising the event found the day to be great fun and highly engaging from their point of view. The engagement and feedback and enthusiasm that we received directly was massively supportive and positive towards the activity. Volunteer feedback focused on the way that the participants were really learning and retaining the information that we were teaching. We found that people engaged with the R4L Rover and Dr Raman the most, but many people completed all parts of the activity as part of the “theme and training program”. The feedback form was completed by 31 people, while 28 people gave written feedback on the question display board. Some photos from the day are shown at Figure 6.

Figure 6:

Multiple shots from SOTSEF 2022 including the rover in demonstration and demonstrators in costume.

3.2

Evaluation Data

We received a wide variety of participants and visitors during the full day at SOTSEF 2022, but the event was tailored towards families with children of varying ages. As can be seen in figure 7b over half of our feedback came from children aged 5-10, with majority of the feedback coming from those under 20s. The activity was designed to engage with as many participants as possible, so the science was simplified by the demonstrators depending on the participants they were interacting with. Figure 7c shows what seems to be a slight male leaning in the participant pool who completed the evaluation form, but this did not fully represent what we saw on the day in terms of overall activity Engagement. Figure 7a shows a large proportion of the participants had never been to a science festival before, with the age range seen in 7b this is potentially due to the impact of the COVID pandemic and the lack of in person events. Thus for much of the younger audience this was often their first event of this type.

Figure 7:

Questionnaire responses a) Have you been to a science festival before? [Yes, No, I don’t know] b) Age? [5-10, 15-20, 25-30, 40-60 60 +] c) Gender? [Open Answer]

We analysed which activities had the most engagement, relevance to daily life and the participants favourite demonstration. It was found that the R4L Rover activity was liked the most, however it had a lower ‘hands on’ engagement score than Dr Raman (See Figure 8). The feedback shows that Dr Raman had the most relevance to people’s daily lives, a trend towards the public being more informed on clinical science since the start of the pandemic.^{20, 44 21} The two supporting activities, rainbow in a box and acoustic Raman scored lower when it came to feedback, but the majority of the responses were positive or at least neutral. This positive response was mirrored by the written feedback (see figure 10).

Figure 8:

With a rating of 1-5: a) What activity did you like the most? b) How relevant was each activity to your daily life? c) What was the best hands-on engagement activity

Figure 9:

a) Describe how clear and engaging the presenters were in explaining the activity? [Very Good, Good, Neutral, Poor, Very Poor, Don’t Know]; b) Did the Mars to Humans activity inspire you to attend another science festival in the future? [Yes, No, I don’t know]; c) What do you think of the way the presenters described the activity? [Very Good, Good, Neutral, Poor, Very Poor, Don’t Know]

Figure 10:

Written Feedback from SOTSEF 2022

As well as engagement and relevance in the topics, we aimed to evaluate the demonstrators and the content that was being taught. As seen in figure 9, entirely positive responses of good or very good were returned for the questions: “ How clear and engaging were the presenters?” and “How well was each scientific idea described?”. This shows a great merit of success for the activities as their descriptions were simple enough, while also being interesting to keep the participants engagement throughout. Dr Raman and R4L had a much higher ratio of very good to good responses, displaying how the activities with more visual and hands-on components had a better response from participants. To measure the success of the event we also asked if this activity had inspired people to attend future science outreach events and festivals. Almost all responses were positive in confirming that they would be interested in future events, the only few outlier results were due to participant uncertainty and confirms the success of the aim in inspiring people who attended the event.

3.3

Feedback conclusions

The evaluation set out to give us an idea of the success and impact of the event and to help us develop the project further. The evaluation survey showed overwhelmingly positive responses to the outreach activity at SOTSEF 2022, with almost all responses reporting great engagement with the topics. We also met the aim of inspiring people, evidence of this being the positive responses to the survey or from the number of written comments responding to the event’s scientific topics. Most of the positive responses were directed towards Dr Raman and R4L, most likely resulting from there topics being more relatable to everyday life as well as their exciting demonstration components. This did not overshadow the other parts of “From Mars to Humans”, instead it showed that the warmup activities could do with some further improvement to increase participant enjoyment and engagement, perhaps focusing future events towards the more popular activities.

3.4

Future Development of “From Mars to Humans”

After a successful flagship event at SOTSEF 2022 we have confirmed that the outreach project ‘From Mars to Humans’ works as a model for future outreach events. We aim to complete further outreach events across the UK developing the project further and really honing the teaching objectives that the project is founded upon. We also aim to produce a full development guide for R4L so that schools, universities, and other groups can recreate the project and equipment for their own purposes. Several upgrades are also planned for the equipment as well as the development of a Mk2 Rover. The new Rover will solve some issues with the original design such as improving the control scheme and allowing the participants to directly control the Rover.