Drop-Carrier Particles for Digital Assays

UC Case No. 2017-533

SUMMARY

UCLA researchers in the Department of Bioengineering have developed a drop-carrier particle for single cell or single molecule assays.

BACKGROUND

Single­-molecule or single­-cell digital assays (e.g. digital PCR, digital LAMP, digital ELISA, drop­Seq) require fractionating or compartmentalizing a large volume to such a level that each smaller fractionated volume contains either one or zero entity of interest (i.e. DNA, protein, etc.). It is critical that each compartment is uniform in volume to allow reactions to proceed with comparable properties in each partition. The main approaches to create these uniform compartments rely on creating monodisperse emulsions of drops using microfluidics. However, there are disadvantages to microfluidic approaches such as high cost for instruments, pumps, and chips to produce these compartmentalized droplets.

INNOVATION

UCLA researchers led by Prof. Dino Di Carlo have developed a new low-cost multi­-material particle that acts as a shuttle or carrier for a desired drop for digital assays. Each particle has a hydrophilic core for substrate or analyte binding, surrounded by a hydrophobic exterior. These types of dual-material particles can be designed with 3D shapes such that they can encapsulate, support, and stabilize water drops in the interior of the particles while being suspended in an oil phase to prevent coalescence of drops needed for digital assays.

POTENTIAL APPLICATIONS

• Digital PCR
• Digital LAMP
• Digital ELISA
• Drop-Sequencing
• Point-of-care diagnostics device

ADVANTAGES

• Only method to create a compartmentalized volume surrounded by one or two particles that have a hydrophilic internal region, and hydrophobic/fluorophilic outer region
• Drop carrier particles can be easily mixed with small volume aqueous samples without complex protocols or instruments and moved between phases and solutions using gravitational or magnetic forces
• Particles can also be made of materials that enable storage of reagents or magnetic properties (e.g. hydrogels or other polymers)