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Keywords:

  • layer-by-layer assembly;
  • microencapsulation;
  • microreactors;
  • polymerization;
  • polyelectrolytes

Graphical Abstract

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A novel microcapsule-based approach to perform a high number of individual polymerase chain reactions (PCR) is demonstrated. Temperature-stable microcapsules with a permeable capsule wall are constructed by matrix-assisted layer-by-layer encapsulation. During the PCR, low molecular dNTPs are supplied externally and diffuse through the permeable capsule wall into the interior, while high molecular weight PCR product are accumulated within the microcapsule. Microcapsules do not exchange templates or primers during PCR cycles and represent individual reaction compartments.

Abstract

A novel approach to perform a high number of individual polymerase chain reactions (PCR) in microcapsule reaction compartments, termed “Microcapsule-PCR” was developed. Temperature stable microcapsules with a selective permeable capsule wall were constructed by matrix-assisted layer-by-layer (LbL) Encapsulation technique. During the PCR, small molecular weight building blocks – nucleotides (dNTPs) were supplied externally and diffuse through the permeable capsule wall into the interior, while the resulted high molecular weight PCR products were accumulated within the microcapsule. Microcapsules (∼110.8 µm average diameter) filled with a PCR reaction mixture were constructed by an emulsion technique having a 2% agarose core and a capsule formed by LbL coating with poly(allylamine-hydrochloride) and poly(4-styrene-sulfonate). An encapsulation efficiency of 47% (measured for primer-FITC (22 bases)) and 98% PCR efficiency was achieved. Microcapsules formed by eight layers of polyelectrolyte and subjected to PCR cycling (up to 95 °C) demonstrated good temperature stability without any significantly changes in DNA retention yield and microcapsule morphology. A multiplex Microcapsule-PCR experiment demonstrated that microcapsules are individual compartment and do not exchange templates or primers between microcapsules during PCR cycling.