Fast and Ultrasensitive Visual Detection of Exosomes in Body Fluids for Point-of-Care Disease Diagnosis

Fast detection of low-concentration exosomes in body fluids is of great significance in understanding the pathogenesis and disease diagnosis but is quite a challenging work due to the complex matrix, tedious pretreatment, and relatively poor sensitivity without the aid of instruments. In this work, by simply using a filter membrane to enrich the exosomes at low concentrations and the use of CuS nanoparticles as labels, Nanjing Medical University researchers were able to detect exosomes at concentrations as low as 2 × 10³ particles/μL in a complex matrix by the naked eye. Due to its high sensitivity, specificity, and simplicity, it can be used for the diagnosis of direct prostate cancer via a 5 mL urine sample within 2 h without the use of any instrument. This method can also be applicable for the detection of other biological nanoparticles, such as viruses, at low concentrations in a complex matrix, offering a promising candidate for point-of-care disease diagnosis with low cost.