{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,7,20]],"date-time":"2026-07-20T07:04:33Z","timestamp":1784531073306,"version":"3.55.0"},"reference-count":27,"publisher":"MDPI AG","issue":"7","license":[{"start":{"date-parts":[[2026,7,18]],"date-time":"2026-07-18T00:00:00Z","timestamp":1784332800000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Biosensors"],"abstract":"<jats:p>Biolayer Interferometry (BLI) has traditionally been used for characterization of protein\u2013protein interactions (PPI) with proteins, such as antibodies and their antigens, through kinetic and quantitation assays. Limitations, for example in sensitivity and the availability of established assay formats, have restricted its adoption across other analytical applications. This article highlights three case studies which demonstrate the expansion of BLI into novel applications, spanning the areas of protein detection and viral vector characterization. The first case study details the use of a multi-step signal amplification assay to enable the detection of low abundant molecules, such as cytokines, at lower concentrations than can be detected using the standard one-step binding approach. Cytokines are sandwiched between biotinylated and HRP-conjugated antibodies, then dipped into 3-amino-9-ethylcarbazole (AEC) reagent, resulting in an enhancement of the cytokine detection sensitivity. The second case study uses BLI for the quantitation of mixed populations of a bispecific antibody (bsAb). Bridging and dual binding assay formats are evaluated for their assessment of bsAb antigen binding kinetics and ability to determine the ratio of correctly assembled bsAb within a sample. In the third case study, BLI detection principles are used to estimate the percentage full capsids in a mixed population of AAV particles. Collectively, these case studies demonstrate the versatility of Octet\u00ae BLI and highlight its potential to support an increasing range of analytical workflows beyond its traditional applications.<\/jats:p>","DOI":"10.3390\/bios16070390","type":"journal-article","created":{"date-parts":[[2026,7,20]],"date-time":"2026-07-20T06:09:09Z","timestamp":1784527749000},"page":"390","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":0,"title":["Expanding Biolayer Interferometry Applications: Enhanced Accuracy, Precision, and Sensitivity in Residual Biomolecule Detection and Quantitation of Bispecifics and AAV Viral Particles"],"prefix":"10.3390","volume":"16","author":[{"given":"Stuart","family":"Knowling","sequence":"first","affiliation":[{"name":"Sartorius Bioanalytical Instruments, 47661 Fremont Blvd, Fremont, CA 94538, USA"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Kirsty","family":"McBain","sequence":"additional","affiliation":[{"name":"Sartorius UK Ltd., Grantham Close, York Way, Royston SG8 5WY, UK"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"David","family":"Apiyo","sequence":"additional","affiliation":[{"name":"Sartorius Bioanalytical Instruments, 47661 Fremont Blvd, Fremont, CA 94538, USA"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1968","published-online":{"date-parts":[[2026,7,18]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"2352","DOI":"10.1021\/es052396q","article-title":"Detection of deoxynivalenol in foods and indoor air using an array biosensor","volume":"40","author":"Ngundi","year":"2006","journal-title":"Environ. Sci. Technol."},{"key":"ref_2","doi-asserted-by":"crossref","first-page":"688","DOI":"10.1080\/19440040903515934","article-title":"Rapid and advanced tools for mycotoxin analysis: A review","volume":"27","author":"Maragos","year":"2010","journal-title":"Food Addit. Contam. Part A Chem. Anal. Control Expo. Risk Assess."},{"key":"ref_3","doi-asserted-by":"crossref","first-page":"112777","DOI":"10.1016\/j.bios.2020.112777","article-title":"Developments in biosensors for CoV detection and future trends","volume":"173","author":"Antiochia","year":"2021","journal-title":"Biosens. Bioelectron."},{"key":"ref_4","doi-asserted-by":"crossref","first-page":"117741","DOI":"10.1016\/j.trac.2024.117741","article-title":"Biolayer interferometry and its applications in drug discovery and development","volume":"176","author":"Jug","year":"2024","journal-title":"TrAC Trends Anal. Chem."},{"key":"ref_5","doi-asserted-by":"crossref","first-page":"e00955","DOI":"10.1016\/j.btre.2026.e00955","article-title":"Comparative analysis of anti-MICA scFv affinities: Insights from three label-free biophysical methods and biological validation","volume":"50","author":"Fehring","year":"2026","journal-title":"Biotechnol. Rep."},{"key":"ref_6","unstructured":"(2023, March 30). Available online: https:\/\/www.ema.europa.eu\/en\/medicines\/human\/EPAR\/briumvi."},{"key":"ref_7","unstructured":"(2024, July 25). Available online: https:\/\/www.ema.europa.eu\/en\/medicines\/human\/EPAR\/tuznue."},{"key":"ref_8","doi-asserted-by":"crossref","unstructured":"Schasfoort, R.B.M. (2017). Handbook of Surface Resonance, Royal Society of Chemistry. [2nd ed.].","DOI":"10.1039\/9781788010283"},{"key":"ref_9","doi-asserted-by":"crossref","first-page":"239","DOI":"10.1016\/j.crimmu.2022.11.001","article-title":"An adaptable in vitro cytokine release assay (CRA): Susceptibility to cytokine storm in COVID-19 as a model","volume":"3","author":"Alam","year":"2022","journal-title":"Curr. Res. Immunol."},{"key":"ref_10","doi-asserted-by":"crossref","unstructured":"Ramesh, P., Shivde, R., Jaishankar, D., Saleiro, D., and Le Poole, I.C. (2021). A Palette of Cytokines to Measure Anti-Tumor Efficacy of T Cell-Based Therapeutics. Cancers, 13.","DOI":"10.3390\/cancers13040821"},{"key":"ref_11","doi-asserted-by":"crossref","first-page":"653","DOI":"10.4161\/mabs.21379","article-title":"Progress in overcoming the chain association issue in bispecific heterodimeric IgG antibodies","volume":"4","author":"Klein","year":"2012","journal-title":"mAbs"},{"key":"ref_12","doi-asserted-by":"crossref","first-page":"11187","DOI":"10.1073\/pnas.1019002108","article-title":"Immunoglobulin domain crossover as a generic approach for the production of bispecific IgG antibodies","volume":"108","author":"Schaefer","year":"2011","journal-title":"Proc. Natl. Acad. Sci. USA"},{"key":"ref_13","doi-asserted-by":"crossref","first-page":"2149053","DOI":"10.1080\/19420862.2022.2149053","article-title":"Kinetic analysis of ternary and binary binding modes of the bispecific antibody emicizumab","volume":"15","author":"Mak","year":"2023","journal-title":"mAbs"},{"key":"ref_14","doi-asserted-by":"crossref","first-page":"1233","DOI":"10.1158\/2159-8290.CD-21-1119","article-title":"Zenocutuzumab, a HER2xHER3 Bispecific Antibody, Is Effective Therapy for Tumors Driven by NRG1 Gene Rearrangements","volume":"12","author":"Schram","year":"2022","journal-title":"Cancer Discov."},{"key":"ref_15","unstructured":"FDA (2025, June 10). FDA Grants Accelerated Approval to Zenocutuzumab-Zbco for Non-Small Cell Lung Cancer and Pancreatic Adenocarcinoma, Available online: https:\/\/www.fda.gov\/drugs\/resources-information-approved-drugs\/fda-grants-accelerated-approval-zenocutuzumab-zbco-non-small-cell-lung-cancer-and-pancreatic."},{"key":"ref_16","doi-asserted-by":"crossref","first-page":"144","DOI":"10.1016\/j.jpba.2014.09.007","article-title":"Development and validation of a novel SPR-based assay principle for bispecific molecules","volume":"102","author":"Gassner","year":"2015","journal-title":"J. Pharm. Biomed. Anal."},{"key":"ref_17","doi-asserted-by":"crossref","first-page":"141","DOI":"10.1016\/j.jpba.2016.09.028","article-title":"SPR-based assays enable the full functional analysis of bispecific molecules","volume":"132","author":"Meschendoerfer","year":"2017","journal-title":"J. Pharm. Biomed. Anal."},{"key":"ref_18","doi-asserted-by":"crossref","first-page":"1231","DOI":"10.1080\/19420862.2017.1367074","article-title":"IgG cooperativity\u2014Is there allostery? Implications for antibody functions and therapeutic antibody development","volume":"9","author":"Yang","year":"2017","journal-title":"mAbs"},{"key":"ref_19","doi-asserted-by":"crossref","first-page":"58","DOI":"10.1080\/19420862.2018.1522178","article-title":"Antigen binding allosterically promotes Fc receptor recognition","volume":"11","author":"Zhao","year":"2019","journal-title":"mAbs"},{"key":"ref_20","doi-asserted-by":"crossref","first-page":"717","DOI":"10.1002\/jgm.1205","article-title":"Recent developments in adeno-associated virus vector technology","volume":"10","author":"Perabo","year":"2008","journal-title":"J. Gene Med."},{"key":"ref_21","first-page":"17","article-title":"Adeno-associated viral vectors as gene delivery vehicles","volume":"6","author":"Carter","year":"2000","journal-title":"Int. J. Mol. Med."},{"key":"ref_22","doi-asserted-by":"crossref","unstructured":"Issa, S.S., Shaimardanova, A.A., Solovyeva, V.V., and Rizvanov, A.A. (2023). Various AAV Serotypes and Their Applications in Gene Therapy: An Overview. Cells, 12.","DOI":"10.3390\/cells12050785"},{"key":"ref_23","doi-asserted-by":"crossref","first-page":"358","DOI":"10.1038\/s41573-019-0012-9","article-title":"Adeno-associated virus vector as a platform for gene therapy delivery","volume":"18","author":"Wang","year":"2019","journal-title":"Nat. Rev. Drug Discov."},{"key":"ref_24","unstructured":"(2026, June 24). Octet\u00ae BLI Technical Note\u2014AAV Empty\/Full Ratio Assessment Using the Octet\u00ae AAVX Biosensors. Available online: https:\/\/www.sartorius.com\/en\/products\/biolayer-interferometry\/bli-resources\/aav-empty-full-ratio."},{"key":"ref_25","doi-asserted-by":"crossref","first-page":"e202200380","DOI":"10.1002\/jbio.202200380","article-title":"Surface Plasmon Resonance based-optical biosensor: Emerging diagnostic tool for early detection of diseases","volume":"16","author":"Singh","year":"2023","journal-title":"J. Biophotonics"},{"key":"ref_26","doi-asserted-by":"crossref","first-page":"492","DOI":"10.1016\/j.talanta.2013.11.063","article-title":"Surface plasmon resonance immunoassay for the detection of the TNF\u03b1 biomarker in human serum","volume":"119","author":"Retolaza","year":"2014","journal-title":"Talanta"},{"key":"ref_27","unstructured":"(2026, February 02). Available online: https:\/\/www.thermofisher.com\/elisa\/product\/Human-TNF-alpha-ELISA-Kit\/KAC1751."}],"container-title":["Biosensors"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.mdpi.com\/2079-6374\/16\/7\/390\/pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2026,7,20]],"date-time":"2026-07-20T06:28:51Z","timestamp":1784528931000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.mdpi.com\/2079-6374\/16\/7\/390"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2026,7,18]]},"references-count":27,"journal-issue":{"issue":"7","published-online":{"date-parts":[[2026,7]]}},"alternative-id":["bios16070390"],"URL":"https:\/\/doi.org\/10.3390\/bios16070390","relation":{},"ISSN":["2079-6374"],"issn-type":[{"value":"2079-6374","type":"electronic"}],"subject":[],"published":{"date-parts":[[2026,7,18]]}}}