Grantee Research Project Results
Final Report: Development of a Novel Virus Capture System Using Positively Charged Silica Matrix
EPA Contract Number: EPD05037Title: Development of a Novel Virus Capture System Using Positively Charged Silica Matrix
Investigators: Hsu, Fu-Chih
Small Business: Scientific Methods, Inc.
EPA Contact: Richards, April
Phase: I
Project Period: March 1, 2005 through August 31, 2005
Project Amount: $69,930
RFA: Small Business Innovation Research (SBIR) - Phase I (2005) RFA Text | Recipients Lists
Research Category: Small Business Innovation Research (SBIR) , Watersheds , SBIR - Water and Wastewater
Description:
The goal of this research project was to develop an electropositive silica matrix functionalized with chemical groups for the efficient capture and release of viruses in water. Different functionalized silica beads were synthesized and tested not only for virus capture, but also to study the efficiency of virus elution from the bead-virus complexes. An optimized surfactant-based elution buffer was developed to facilitate release of viruses from the capture surface by testing different types of surfactants that alter the bead surface charge. Defined buffer components also were evaluated to optimize virus dissociation from functionalized bead surfaces. At the conclusion of the project, prototype beads and buffers were used to recover viruses from large volumes of tap water.
Summary/Accomplishments (Outputs/Outcomes):
Scientific Methods, Inc., developed functionalized silica particles with positively charged surfaces that were employed to capture and recover viruses seeded into water samples. Virus capture on the functionalized silica surface occurs on the basis of specific molecular interactions including electrostatic attraction and hydrogen bonding between the positively charged functionalized groups and the negatively charged viral particles. Optimized elution buffers containing soluble proteins or defined eluants (amino acids plus surfactant) were developed to recover captured viruses from the silica matrix. Scientific Methods, Inc., found that short-chain functional groups exhibit highly efficient virus capture, but the efficiency of release was relatively low. Conversely, silica particles functionalized with long-chain surface groups can both capture and release viruses efficiently. By carefully tuning the chain length and the density of functionalization on the silica surface, capture efficiencies approaching 100 percent can be achieved. The zeta potentials of the functionalized silica particles were analyzed and used for monitoring the extent of functionalization and the charge behavior of the functionalized silica surfaces. Overall recoveries of viruses from silica beads ranged from 13 to 80 percent when 20-40 L volumes of water were seeded with viruses and an alkaline elution buffer containing soluble protein or amino acids was employed. Because the traditional methods for detecting viruses are cumbersome, time-consuming, and costly, the development of a class of functionalized silica material that can rapidly and efficiently concentrate viruses from water offers the possibility of improved detection methods for waterborne pathogens.
Conclusions:
The functionalized silica beads have demonstrated several advantages for virus concentration. The material can be produced at reasonable cost and is easy to use. The functionalized beads can be packed into a variety of filter formats to accommodate different applications such as analytic recovery of viruses from water or point-of-use treatment for production of drinking water. Moreover, the small volumes of eluant (less than 75 mL) produced from 40 L sample volumes make it possible to move directly to a diagnostic assay without having to employ cumbersome and time-consuming concentration techniques (e.g., organic flocculation). During this Phase I research project, Scientific Methods, Inc., identified specific functionalization materials and procedures that can be used to capture viruses across a range of contamination levels and under a broad pH range (3-9). In addition, silica bead preparations have been identified that are capable of binding viruses irreversibly, suggesting the potential for use as point-of-use treatment products.
Supplemental Keywords:
virus capture system, positively charged silica matrix, silica beads, drinking water, tap water, functionalized silica beads, virus concentration, point-of-use water treatment, waterborne pathogens, filtration, groundwater, zeta potential, positively charged filter, EPA, small business, SBIR,, RFA, Scientific Discipline, Water, POLLUTANTS/TOXICS, Environmental Chemistry, Drinking Water, Microorganisms, Environmental Engineering, CCL, viruses, adenoviruses, calciviruses, community water system, echoviruses, silica matrix, water disinfection, drinking water contaminants, drinking water treatment, silicate sorbent, electrostatic attraction virus captureSBIR Phase II:
Development of a Novel Virus Capture System Using Positively Charged Silica MatrixThe perspectives, information and conclusions conveyed in research project abstracts, progress reports, final reports, journal abstracts and journal publications convey the viewpoints of the principal investigator and may not represent the views and policies of ORD and EPA. Conclusions drawn by the principal investigators have not been reviewed by the Agency.