A CRISPR mediated point-of-care assay for the detection of mucosal calprotectin in an animal model of ulcerative colitis

Inflammatory bowel disease (IBD) is a chronic disorder associated with inflammation in the gastrointestinal tract, leading to a range of debilitating symptoms. Fecal calprotectin is an established biomarker for ulcerative colitis (UC), one of the main IBD diseases, which provides indications of the presence and severity of inflammation in the digestive tract. Enzyme-Linked Immunosorbent Assay (ELISA) as a gold standard approach for fecal calprotectin detection is time-consuming and impractical in point-of-care settings. Moreover, obtaining fecal samples from patients is challenging and inhibits longitudinal monitoring. To overcome these limitations, we designed a new approach for detecting calprotectin which leverages clustered regularly interspaced short palindromic repeats (CRISPR)/Cas technology. We successfully developed a portable tube-based CRISPR/Cas assay for point-of-care testing of calprotectin. This assay showed a detection range from 1-10000 ng/mL (over 4 log units), using both fluorescent and colorimetric analytical techniques. The established assay was further validated through measurements in mucosal samples obtained in an anesthetised preclinical rodent model of UC, with 2-3 times higher calprotectin concentration detected in UC rat samples compared to that of healthy control animals. This point-of-care test may provide a rapid, precise, and user-friendly approach for the diagnosis and monitoring of IBD through mucosal sample testing. ### Competing Interest Statement The authors have declared no competing interest. ### Funding Statement This study is supported by a UNSW SHARP fund and UNSW Mental Health & Addiction Theme Seed Funding. ### Author Declarations I confirm all relevant ethical guidelines have been followed, and any necessary IRB and/or ethics committee approvals have been obtained. Yes I confirm that all necessary patient/participant consent has been obtained and the appropriate institutional forms have been archived, and that any patient/participant/sample identifiers included were not known to anyone (e.g., hospital staff, patients or participants themselves) outside the research group so cannot be used to identify individuals. Yes I understand that all clinical trials and any other prospective interventional studies must be registered with an ICMJE-approved registry, such as [ClinicalTrials.gov][1]. I confirm that any such study reported in the manuscript has been registered and the trial registration ID is provided (note: if posting a prospective study registered retrospectively, please provide a statement in the trial ID field explaining why the study was not registered in advance). Yes I have followed all appropriate research reporting guidelines, such as any relevant EQUATOR Network research reporting checklist(s) and other pertinent material, if applicable. Yes All data produced in the present work are contained in the manuscript [1]: http://ClinicalTrials.gov