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Department of Veterinary Medicine

Cambridge Veterinary School

The Department of Veterinary Medicine is pioneering a new approach to its cellular analysis research facilities provision, based on providing complimentary techniques suited to cellular analysis, along-side hands-on, dedicated expertise, rather than a suite of standalone instruments. I lead the cellular imaging and analysis research facilities, bringing help and expertise in fluorescence imaging techniques, including microscopy, imaging flow cytometry and conventional cytometry to the department, in the form of training and support for the use of facility equipment, full service and project runs and consultancy on quantitative imaging and flow cytometry projects and data analysis.

This relatively new and alternative approach is borne from the experience of researchers, understanding the complexity of modern advances in imaging techniques and instrumentation. Alongside the benefit and sometimes necessity of utilizing advanced complimentary techniques in parallel, in order to achieve the most accurate and insightful data.

Cellular Imaging and Analysis Facility | Department of Veterinary Medicine Research Facilities (

I am especially passionate about the use of imaging techniques for quantitative deep profiling of cells and internal cellular processes, to advance our understanding of cellular mechanisms in health and disease, and for the development of novel therapeutics and technologies. My own research interests include investigating how nano and sub-micron sized particles influence cellular immune responses, as well as the development of modern cell culture techniques to address sustainability and food security challenges, utilizing conventional and imaging flow cytometry as key techniques.


I am a Cellular Immunologist specialised in primary cell culture and analysis. My PhD focused on dietary microparticles and adaptive immunity, this naturally progressed into research contributiing to the understanding of how some particulate food additive and excipients interact with immune cells. Hand in hand with contributing to advances in quantitative techniques with the use of advanced cellular analysis and machine learning platforms. My studies have resulted in 2 patents for which I am an inventor.
I now lead the Cellular Imaging and Analysis Research Facilities at the Department of Veterinary Medicine. I regularly advise on multiple, diversely funded projects requiring cellular analyses whilst continuing to pursue my own research interests. These include investigating the effects of environmental particulate exposures and exploiting the use of advanced cellular techniques to address sustainability and food security challenges.


Key publications: 
Google Scholar List of Publications ‪Rachel E. Hewitt‬ - ‪Google Scholar‬

Editorial: Modulation of the immune system by nanoparticles. Hewitt RE, De Marzi MC, Ng KW. Front Immunol. 2023 Apr 11;14:1190966. doi: 10.3389/fimmu.2023.1190966.Label-Free

Identification of Persistent Particles in Association with Primary Immune Cells by Imaging Flow Cytometry. Vis B, Powell JJ, Hewitt RE. Methods Mol Biol. 2023;2635:135-148. doi: 10.1007/978-1-0716-3020-4_8.

Formulation of Metal-Organic Framework-Based Drug Carriers by Controlled Coordination of Methoxy PEG Phosphate: Boosting Colloidal Stability and Redispersibility. Chen X, Zhuang Y, Rampal N, Hewitt R, Divitini G, O'Keefe CA, Liu X, Whitaker DJ, Wills JW, Jugdaohsingh R, Powell JJ, Yu H, Grey CP, Scherman OA, Fairen-Jimenez D. J Am Chem Soc. 2021 Sep 1;143(34):13557-13572. doi: 10.1021/jacs.1c03943.

Small and dangerous? Potential toxicity mechanisms of common exposure particles and nanoparticles. Hewitt RE, Chappell HF, Powell JJ. Curr Opin Toxicol. 2020 Feb;19:93-98. doi: 10.1016/j.cotox.2020.01.006.

Ultrasmall silica nanoparticles directly ligate the T cell receptor complex. Vis B, Hewitt RE, Monie TP, Fairbairn C, Turner SD, Kinrade SD, Powell JJ. Proc Natl Acad Sci U S A. 2020 Jan 7;117(1):285-291. doi: 10.1021/acsnano.8b03363

Imaging flow cytometry methods for quantitative analysis of label-free crystalline silica particle interactions with immune cells. Vis B, Powell JJ, Hewitt RE. AIMS Biophys. 2020;7(3):144-166. doi: 10.3934/biophy.2020012

Non-Functionalized Ultrasmall Silica Nanoparticles Directly and Size-Selectively Activate T Cells. Vis B, Hewitt RE, Faria N, Bastos C, Chappell H, Pele L, Jugdaohsingh R, Kinrade SD, Powell JJ. ACS Nano. 2018 Nov 27;12(11):10843-10854. doi: 10.1021/acsnano.8b03363.

Imaging flow cytometry assays for quantifying pigment grade titanium dioxide particle internalization and interactions with immune cells in whole blood. Hewitt RE, Vis B, Pele LC, Faria N, Powell JJ. Cytometry A. 2017 Oct;91(10):1009-1020. doi: 10.1002/cyto.a.23245

Reduction of T-Helper Cell Responses to Recall Antigen Mediated by Codelivery with Peptidoglycan via the Intestinal Nanomineral-Antigen Pathway. Hewitt RE, Robertson J, Haas CT, Pele LC, Powell JJ. Front Immunol. 2017 Mar 17;8:284. doi: 10.3389/fimmu.2017.00284

Synthetic mimetics of the endogenous gastrointestinal nanomineral: Silent constructs that trap macromolecules for intracellular delivery. Pele LC, Haas CT, Hewitt RE, Robertson J, Skepper J, Brown A, Hernandez-Garrido JC, Midgley PA, Faria N, Chappell H, Powell JJ. Nanomedicine. 2017 Feb;13(2):619-630. doi: 10.1016/j.nano.2016.07.008

An endogenous nanomineral chaperones luminal antigen and peptidoglycan to intestinal immune cells. Powell JJ, Thomas-McKay E, Thoree V, Robertson J, Hewitt RE, Skepper JN, Brown A, Hernandez-Garrido JC, Midgley PA, Gomez-Morilla I, Grime GW, Kirkby KJ, Mabbott NA, Donaldson DS, Williams IR, Rios D, Girardin SE, Haas CT, Bruggraber SF, Laman JD, Tanriver Y, Lombardi G, Lechler R, Thompson RP, Pele LC. Nat Nanotechnol. 2015 Apr;10(4):361-9. doi: 10.1038/nnano.2015.19

Immuno-inhibitory PD-L1 can be induced by a peptidoglycan/NOD2 mediated pathway in primary monocytic cells and is deficient in Crohn's patients with homozygous NOD2 mutations. Hewitt RE, Pele LC, Tremelling M, Metz A, Parkes M, Powell JJ. Clin Immunol. 2012 May;143(2):162-9. doi: 10.1016/j.clim.2012.01.016

MHC class I molecules with Superenhanced CD8 binding properties bypass the requirement for cognate TCR recognition and nonspecifically activate CTLs. Wooldridge L, Clement M, Lissina A, Edwards ES, Ladell K, Ekeruche J, Hewitt RE, Laugel B, Gostick E, Cole DK, Debets R, Berrevoets C, Miles JJ, Burrows SR, Price DA, Sewell AK. J Immunol. 2010 Apr 1;184(7):3357-66. doi: 10.4049/jimmunol.0902398


Senior Research Associate
Cellular Imaging & Analysis Research Facility Manager
Available for consultancy


Local Affiliations: 
Person keywords: 
Cellular Immunology
Fluorescence Imaging
Biosciences and Biotechnology Research Council
BSAVA Petsavers
Innovate UK