Rapid High-Resolution Visible-Light 3D Printing of Hydrogels via Nanocluster-Triggered Dual-Pathway Photoinitiation

Area of Science:

• Materials Science
• Biomedical Engineering
• Photochemistry

Background:

• Vat photopolymerization is crucial for biomedical applications but faces challenges in achieving high-speed and high-resolution hydrogel printing.
• Current UV-based methods (<420 nm) and some visible-light systems exhibit limitations like slow reaction times, oxygen sensitivity, and product discoloration.

Purpose of the Study:

• To address limitations in visible-light-driven hydrogel 3D printing by introducing a nanocluster-triggered dual-pathway photoinitiation system.
• To enhance printing speed, resolution, and product clarity for complex hydrogel structures.

Main Methods:

• Utilized silver (Ag) nanoclusters as photoinitiators for visible light (405-560 nm) vat photopolymerization.
• Investigated the dual-pathway photoinitiation mechanism involving Ag nanocluster photodegradation via interfacial Ag-S bond scission (Type-I) and proton abstraction (Type-II) from amino acids.
• Employed spectroscopic analysis to understand radical generation and photochemical pathways.

Main Results:

• Ag nanoclusters demonstrated superior initiation efficiency and improved printing resolution compared to traditional photoinitiators.
• The photodegradable nature of Ag nanoclusters resulted in optically clear hydrogel products.
• Identified dual radical generation pathways (Type-I and Type-II) contributing to high photoinitiation performance.

Conclusions:

• Nanocluster-triggered dual-pathway photoinitiation offers a promising solution for high-speed, high-resolution visible-light 3D printing of hydrogels.
• The findings provide new photochemical insights into nanocluster behavior and radical generation.
• This work encourages further exploration of nanocluster-based materials for advanced 3D printing applications.