3D printing soluble solids via PISA

Abstract

Polymer-Induced Self Assembly (PISA) is a technique that often involves the use of a macro-chain transfer agent (macro-CTA) polymerized through reversible addition-fragmentation chain transfer (RAFT), which is then chain extended...

PISA Printing Microneedles with Controllable Aqueous Dissolution Kinetics

“…The goals of this study were 3-fold: first, to assess the ability to create high-resolution objects using the PISA printing method; second, to confirm that these objects are not cross-linked and can dissolve in suitable solvents; and third, to create resin mixtures that print well in organic solvents such as isopropanol but can also dissolve at controlled rates under physiological conditions. In our previous PISA printing study, we found that the use of macro-CTAs with multiple RAFT CTAs is crucial for achieving the mechanical strength necessary to PISA print objects with a DLP printer . We hypothesize that the mechanical stability of the printed objects arises from a combination of interparticle bridging and knotting among the soluble corona-stabilizing segments (Figure A,B).…”

“…In our previous PISA printing study, we found that the use of macro-CTAs with multiple RAFT CTAs is crucial for achieving the mechanical strength necessary to PISA print objects with a DLP printer. 17 We hypothesize that the mechanical stability of the printed objects arises from a combination of interparticle bridging and knotting among the soluble corona-stabilizing segments (Figure 1A,B). To prepare macro-CTAs with multiple covalently bound CTAs, we first homopolymerized a RAFT transmer to produce a highly branched polymer.…”

“…15,16 We recently reported the development of RAFT polymerization-induced self-assembly (RAFT PISA) printing, which allows parts to be 3D printed without the need for multifunctional cross-linking monomers. 17 This methodology yields parts that are stabilized by physical rather than chemical cross-links. Similar to conventional PISA, PISA printing employs a RAFT macrochain transfer agent (macro-CTA) that is chain extended with a monomer that phase separates during block copolymer formation.…”

“…Digital light processing (DLP) 3D printers are known for high resolution and have been used extensively in biomedical engineering, particularly in the fabrication of microfluidic devices. − However, these traditional methods often lack precise control over polymer architecture, a limitation addressed by reversible deactivation radical polymerization (RDRP) techniques. − Reversible addition–fragmentation chain transfer (RAFT) polymerization, a subset of RDRP, has gained attention for its applications in 3D printing. Boyer et al demonstrated the use of RAFT for 3D and 4D prints, achieving rapid polymerization and build speeds. − Other researchers have similarly applied RAFT-based photopolymerization in DLP printing, offering improvements in mechanical properties and glass transition temperatures. − RAFT techniques also enhance thermomechanical properties and allow for postmodification capabilities that are not feasible with traditional methods. , We recently reported the development of RAFT polymerization-induced self-assembly (RAFT PISA) printing, which allows parts to be 3D printed without the need for multifunctional cross-linking monomers . This methodology yields parts that are stabilized by physical rather than chemical cross-links.…”

PISA printing from CTA functionalized polymer scaffolds

“…Our initial work on RAFT PISA printing utilized a difunctional poly(ethylene glycol) (PEG) macro-CTA, chain extended with diacetone acrylamide (DAAm) in water, and 3D printed via DLP using lithium phenyl-2,4,6-trimethylbenzoylphosphinate (LAP) as a photo-initiator and phenol red as a photoabsorber. 29 In this study, we observed the dissolution behavior of DAAm PISA frogs in N , N -dimethylformamide (DMF), noting that those without N ′ N -methylene bisacrylamide (MBAc) crosslinker dissolved completely, indicating the presence of physical crosslinks. Building on this foundation, our second PISA printing study aimed to develop formulations capable of dissolving in physiological fluids with controlled kinetics.…”