A system for automated synthesis of particles, the particles containing at least one polyelectrolyte layer deposited onto a substrate core, the system comprising: a computer, a tangential flow filtration component, and a soluble reagent addition manifold component; the TFF component comprising a TFF loop and a permeate valve, wherein the TFF loop comprises: a TFF circulatory loop pump (18, 67), a particle reservoir containing substrate cores, a connecting means, and a TFF filter connected to the particle reservoir by the connecting means; the computer being arranged to control the permeate valve to selectively release permeate from the TFF filter; the soluble reagent addition manifold component including at least one soluble reagent (32, 34; 56, 58; 88, 89) and at least one reagent valve (31, 33, 35, 37, 44, 93, 95), wherein the soluble reagent (32, 34; 56, 58; 88, 89) includes a polyelectrolyte; the computer being arranged to control the at least one reagent valve (31, 33, 35, 37, 44, 93, 95) to deliver the at least one soluble reagent (32, 34; 56, 58; 88, 89) from the soluble reagent delivery manifold component to the TFF component to form a mixture with the substrate cores; characterised in that the soluble reagent delivery manifold component comprises a plurality of soluble reagents (32, 34; 56, 58; 88, 89) and a plurality of reagent valves (31, 33, 35, 37, 44, 93, 95), the reagents (32, 34; 56, 58; 88, 89) including oppositely charged polyelectrolytes; and the computer is arranged to control the permeate valve and the plurality of reagent valves (31, 33, 35, 37, 44, 93, 95) to perform automatic layer by layer formation of multilayered films containing a plurality of oppositely charged polyelectrolyte layers while the TFF circulatory loop pump (18, 67) recirculates the mixture through the TFF loop by performing: automated delivery of a defined volume of a first one of the soluble reagents (32, 34; 56, 58; 88, 89) to the tangential flow filtration component; mixing of the first soluble reagent (32, 34; 56, 58; 88, 89) with the substrate core particles for a defined time; eliminating of excess of the first soluble reagent (32, 34; 56, 58; 88, 89) by permeation for a defined volume; and delivering a defined volume of a second one of the soluble reagents (32, 34; 56, 58; 88, 89) having an opposite polarity to the polyelectrolyte in the first soluble reagent. a computer, a tangential flow filtration component, and a soluble reagent addition manifold component; the TFF component comprising a TFF loop and a permeate valve, wherein the TFF loop comprises: a TFF circulatory loop pump (18, 67), a particle reservoir containing substrate cores, a connecting means, and a TFF filter connected to the particle reservoir by the connecting means; a TFF circulatory loop pump (18, 67), a particle reservoir containing substrate cores, a connecting means, and a TFF filter connected to the particle reservoir by the connecting means; the computer being arranged to control the permeate valve to selectively release permeate from the TFF filter; the soluble reagent addition manifold component including at least one soluble reagent (32, 34; 56, 58; 88, 89) and at least one reagent valve (31, 33, 35, 37, 44, 93, 95), wherein the soluble reagent (32, 34; 56, 58; 88, 89) includes a polyelectrolyte; the computer being arranged to control the at least one reagent valve (31, 33, 35, 37, 44, 93, 95) to deliver the at least one soluble reagent (32, 34; 56, 58; 88, 89) from the soluble reagent delivery manifold component to the TFF component to form a mixture with the substrate cores; characterised in that the soluble reagent delivery manifold component comprises a plurality of soluble reagents (32, 34; 56, 58; 88, 89) and a plurality of reagent valves (31, 33, 35, 37, 44, 93, 95), the reagents (32, 34; 56, 58; 88, 89) including oppositely charged polyelectrolytes; and the computer is arranged to control the permeate valve and the plurality of reagent valves (31, 33, 35, 37, 44, 93, 95) to perform automatic layer by layer formation of multilayered films containing a plurality of oppositely charged polyelectrolyte layers while the TFF circulatory loop pump (18, 67) recirculates the mixture through the TFF loop by performing: automated delivery of a defined volume of a first one of the soluble reagents (32, 34; 56, 58; 88, 89) to the tangential flow filtration component; mixing of the first soluble reagent (32, 34; 56, 58; 88, 89) with the substrate core particles for a defined time; eliminating of excess of the first soluble reagent (32, 34; 56, 58; 88, 89) by permeation for a defined volume; and delivering a defined volume of a second one of the soluble reagents (32, 34; 56, 58; 88, 89) having an opposite polarity to the polyelectrolyte in the first soluble reagent. automated delivery of a defined volume of a first one of the soluble reagents (32, 34; 56, 58; 88, 89) to the tangential flow filtration component; mixing of the first soluble reagent (32, 34; 56, 58; 88, 89) with the substrate core particles for a defined time; eliminating of excess of the first soluble reagent (32, 34; 56, 58; 88, 89) by permeation for a defined volume; and delivering a defined volume of a second one of the soluble reagents (32, 34; 56, 58; 88, 89) having an opposite polarity to the polyelectrolyte in the first soluble reagent.