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To be successfully implemented as drug carriers, efficient loading of drugs into exosomes is crucial, and a deeper understanding of the loading mechanism remains to be solved. This study introduces surface-enhanced Raman scattering (SERS) to monitor drug loading efficacy at the single vesicle level. By enhancing the Raman signal, SERS overcomes limitations in Raman spectroscopy. A gold nanopyramids array-based SERS substrate assesses exosome heterogeneity in drug-loading capabilities with the help of single-layer graphene for precise quantification. This research advances targeted drug delivery by presenting a more efficient method of evaluating drug-loading efficiency into individual exosomes through SERS-based monitoring. Furthermore, the study explores leveraging osmotic pressure variations, enhancing the efficiency of drug loading into exosomes.<\/jats:p>","DOI":"10.3390\/bios15030141","type":"journal-article","created":{"date-parts":[[2025,2,24]],"date-time":"2025-02-24T05:36:47Z","timestamp":1740375407000},"page":"141","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":11,"title":["On the Feasibility of SERS-Based Monitoring of Drug Loading Efficiency in Exosomes for Targeted Delivery"],"prefix":"10.3390","volume":"15","author":[{"ORCID":"https:\/\/orcid.org\/0000-0002-9670-1033","authenticated-orcid":false,"given":"Jun","family":"Liu","sequence":"first","affiliation":[{"name":"Department of Materials Science and Engineering, University of California Los Angeles, Los Angeles, CA 90095, USA"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Siddharth","family":"Srivastava","sequence":"additional","affiliation":[{"name":"Department of Materials Science and Engineering, University of California Los Angeles, Los Angeles, CA 90095, USA"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Tieyi","family":"Li","sequence":"additional","affiliation":[{"name":"Department of Materials Science and Engineering, University of California Los Angeles, Los Angeles, CA 90095, USA"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Faycal","family":"Moujane","sequence":"additional","affiliation":[{"name":"Cornea Division, Stein Eye Institute, University of California Los Angeles, Los Angeles, CA 90095, USA"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"John Y.","family":"Lee","sequence":"additional","affiliation":[{"name":"Cornea Division, Stein Eye Institute, University of California Los Angeles, Los Angeles, CA 90095, USA"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Yiqing","family":"Chen","sequence":"additional","affiliation":[{"name":"Department of Bioengineering, University of California Riverside, Riverside, CA 92521, USA"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-9366-6204","authenticated-orcid":false,"given":"Huinan","family":"Liu","sequence":"additional","affiliation":[{"name":"Department of Bioengineering, University of California Riverside, Riverside, CA 92521, USA"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Sophie X.","family":"Deng","sequence":"additional","affiliation":[{"name":"Cornea Division, Stein Eye Institute, University of California Los Angeles, Los Angeles, CA 90095, USA"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-0971-4280","authenticated-orcid":false,"given":"Ya-Hong","family":"Xie","sequence":"additional","affiliation":[{"name":"Department of Materials Science and Engineering, University of California Los Angeles, Los Angeles, CA 90095, USA"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1968","published-online":{"date-parts":[[2025,2,23]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"7","DOI":"10.3322\/caac.21708","article-title":"Cancer statistics, 2022","volume":"72","author":"Siegel","year":"2022","journal-title":"CA Cancer J. 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