Body Fluid Identification and Classification

Body Fluid Identification and Classification

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This webinar originally occurred on November 9, 2023
Duration: 1 hour


In the first installment of the R&D Webinar Series, Sarah Seashols-Williams, Ph.D., from Virginia Commonwealth University, will demonstrate the ability to classify body fluids using miRNA expression from DNA extracts with 92% accuracy, eliminating the need for RNA extraction, greatly reducing evidentiary sample consumption and processing time in forensic laboratories. 

Additionally, Samriddha Dutta from the University of California, Riverside, will present her work on developing a chemiresistive nanobiosensor array with single-walled carbon nanotubes on paper, enabling on-site identification of body fluids (blood, semen, saliva, urine, sweat) via protein biomarkers. This innovative system, with its high sensitivity and minimal sample requirements, holds significant promise for advancing forensic science and investigations.  

Detailed Learning Objectives

  1. Attendees will gain an understanding of the innovative chemiresistive nanobiosensor array technology using Single-Walled Carbon Nanotubes for on-site identification of multiple body fluids and the role of protein biomarkers in this process.
  2. Attendees will be briefed on miRNA detection as a means for body fluid classification and recognize that miRNA detection in DNA extracts is possible.
  3. Attendees will be able to describe why a quantitative classification of body fluid origin is preferable to traditional serological techniques. 


  • Sarah Seashols-Williams, Ph.D. | Associate Professor, Virginia Commonwealth University 
  • Samriddha Dutta, M.S. | Ph.D. Candidate, University of California, Riverside

Body Fluid Classification Using an miRNA Panel in DNA Extracts

Sarah Seashols-Williams, Ph.D., from Virginia Commonwealth University will present on Body Fluid Classification using an miRNA panel in DNA Extracts. Molecular-based approaches for biological source identification are of great interest in the forensic community because of a lack of sensitivity and specificity in current methods. MicroRNAs (miRNAs) have been the subject of many body fluid identification studies due to their robust nature and tissue specificity. However, their analysis requires a separate RNA extraction, requiring an additional step in the forensic analysis workflow.  

The purpose of this project was to build on previous work in which the team identified a panel of 8 miRNAs that can identify blood, semen, menstrual secretions, vaginal secretions, feces, urine, and saliva. As part of two previously NIJ-funded projects, a pilot study was conducted showing miRNAs are consistently detectable using several DNA extraction methods commonly utilized in the field for forensic casework. It was reported that the miRNA panel for forensic body fluid identification was evaluated using DNA extracts of semen, saliva, blood and menstrual secretions, and the results were largely concordant with those from samples deriving from RNA extracts.  

This project evaluated a larger sample set of DNA extracts and evaluated miRNA expression using the method previously validated for RNA extracts using RT-qPCR analysis of DNA extracts. A quantitative discriminant analysis (QDA) model was developed using these data and demonstrated an accuracy of 92% in body fluid classification. The validated QDA model is now available on a public website for testing by the research community. 

The panel of miRNA markers were shown to have a high specificity for identifying six biological fluids in DNA extracts using QDA and is a promising alternative to traditional serological tests for forensic casework. This is a simple RT-qPCR assay that uses only a small portion of the DNA extract to identify the body fluid(s) present in the evidence, with no additional sample use or personnel time in producing a separate RNA extract. 

Advanced Forensic Methods: Identifying Body Fluids at Crime Scenes

In her study, Advanced Forensic Methods: Identifying Body Fluids at Crime Scenes, Samriddha Dutta from the University of California, Riverside, aims to enhance forensic investigations by addressing the challenge of identifying body fluids at crime scenes. Dutta and her team are developing an innovative chemiresistive nanobiosensor array using Single-Walled Carbon Nanotubes (SWNT) on chromatography paper. This technology enables quantitative, selective, on-site identification of body fluids, namely blood, semen, saliva, urine, and sweat, through detection of their protein biomarkers using corresponding antibodies. The sensor array requires minimal sample volume, distributed efficiently through the built-in paper microfluidics.  

From literature, two sets of unique biomarker proteins have been identified for each targeted body fluid. Individual antibodies are immobilized on SWNTs, and specific antigen-antibody interactions near the SWNT-environment interface induce significant electrical responses, forming the basis for the sensor's output. To simplify and expedite multiplexed sensing, there has been further development of an all-in-one style water-based SWNT-Antibody Bioink, containing both the transducer (SWNT) and biological element (antibody) that can be drop-casted or printed on the substrate. Quantitative and selective detection of the proteins can be demonstrated with the very low limit of detection values obtained. Collectively, this biosensing platform is exhibiting promising potential for unprecedented point-of-crime scene investigations.

Funding for this Forensic Technology Center of Excellence webinar has been provided by the National Institute of Justice, Office of Justice Programs, U.S. Department of Justice.

The opinions, findings, and conclusions or recommendations expressed in this webinar are those of the presenter(s) and do not necessarily reflect those of the U.S. Department of Justice.

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