Hollow silica microspheres for buoyancy-assisted separation of infectious pathogens from stool.
Separation of cells and microorganisms from complex biological mixtures is a critical first step in many analytical applications ranging from clinical diagnostics to environmental monitoring for food and waterborne contaminants. Yet, existing techniques for cell separation are plagued by high reagent and/or instrumentation costs that limit their use in many remote or resource-poor settings, such as field clinics or developing countries. We developed an innovative approach to isolate infectious pathogens from biological fluids using buoyant hollow silica microspheres that function as "molecular buoys" for affinity-based target capture and separation by floatation. In this process, antibody functionalized glass microspheres are mixed with a complex biological sample, such as stool. When mixing is stopped, the target-bound, low-density microspheres float to the air/liquid surface, which simultaneously isolates and concentrates the target analytes from the sample matrix. The microspheres are highly tunable in terms of size, density, and surface functionality for targeting diverse analytes with separation times of ≤2min in viscous solutions. We have applied the molecular buoy technique for isolation of a protozoan parasite that causes diarrheal illness, Cryptosporidium, directly from stool with separation efficiencies over 90% and low non-specific binding. This low-cost method for phenotypic cell/pathogen separation from complex mixtures is expected to have widespread use in clinical diagnostics as well as basic research.
Materials Science, Engineering, and Commercialization Program, Texas State University, San Marcos, TX 78666, USA; Department of Biology, Texas State University, San Marcos, TX 78666, USA. Electronic address: sweigum@txstate.edu.
Shannon E
SE
Weigum
Materials Science, Engineering, and Commercialization Program, Texas State University, San Marcos, TX 78666, USA.
Lichen
L
Xiang
Department of Biology, Texas State University, San Marcos, TX 78666, USA.
Erica
E
Osta
Department of Biomedical Engineering, Duke University, Durham, NC 27708, USA; NSF Research Triangle Materials Research Science and Engineering Center, Durham, NC 27708, USA.
Linying
L
Li
Department of Biomedical Engineering, Duke University, Durham, NC 27708, USA; NSF Research Triangle Materials Research Science and Engineering Center, Durham, NC 27708, USA; Center for Biomedical Engineering, Department of Chemical and Biomedical Engineering, University of New Mexico, Albuquerque, NM 87131, USA.
Gabriel P
GP
López
D002469:Cell Separation / Q000295:instrumentation / Q000379:methods*; D003458:Cryptosporidium / Q000737:chemistry / Q000302:isolation & purification*; D005243:Feces / Q000737:chemistry* / Q000469:parasitology; D006801:Humans; D008863:Microspheres; D012822:Silicon Dioxide / Q000737:chemistry*
D012822:Silicon Dioxide
Analyte concentration and isolation; Bioseparation; Buoyancy cell separation; Glass microbubbles; Sample preparation