NUS Optofluidic 3D Micro Nano-Printing Breakthrough: Beyond Polymers in Nature

Revolutionizing Microscale Fabrication: NUS-MPI Collaboration Unveils Optofluidic Technique

The National University of Singapore (NUS) has made headlines in the world of advanced manufacturing with a groundbreaking publication in Nature on January 28, 2026. Titled "Optofluidic three-dimensional microfabrication and nanofabrication," the paper introduces a novel method that shatters the material constraints of traditional 3D printing technologies. Led by NUS Assistant Professor Mingchao Zhang alongside experts from the Max Planck Institute for Intelligent Systems (MPI-IS), this innovation enables the precise assembly of nanoparticles into complex three-dimensional (3D) structures using metals, ceramics, semiconductors, and more—far beyond the polymer limitations that have long plagued the field.

This development positions Singapore's higher education institutions at the forefront of materials science and engineering, promising transformative impacts on microrobotics, microfluidics, and beyond. For researchers and engineers, it means access to a versatile "toolbox" of materials for crafting tiny devices with tailored properties.

Overcoming the Polymer Bottleneck in 3D Micro and Nanofabrication

Conventional 3D micro- and nanofabrication techniques, such as two-photon polymerization (2PP), have excelled in creating intricate polymer-based structures at scales smaller than a human hair. However, these methods are severely limited to photosensitive polymers, restricting applications that demand diverse material properties like electrical conductivity, magnetism, or catalytic activity.

Imagine trying to sculpt detailed models using only one type of modeling clay—functional but inflexible. The NUS-MPI team's optofluidic approach changes this by harnessing light-induced fluid dynamics to assemble nanoparticles from virtually any material dispersion. This universality opens doors to multifunctional microstructures previously deemed science fiction.

The Science Behind Optofluidic Assembly: A Step-by-Step Breakdown

At its core, the technique combines precision laser control with fluid mechanics. Here's how it unfolds:

• Template Fabrication: A hollow polymer micromold—shaped like a cube, sphere, or even a croissant—is printed using 2PP lithography on a glass substrate. This template has a single small opening for particle entry.
• Immersion: The template is submerged in a liquid dispersion containing micro- or nanoparticles (e.g., 150 nm to 1 µm SiO₂ spheres).
• Laser Activation: A femtosecond laser (780 nm wavelength) targets a point near the opening, creating a localized hotspot up to 2,293 K. This generates thermal gradients driving convective flows via buoyancy and Marangoni effects.
• Particle Propulsion: Optofluidic flows (speeds up to several mm/s) propel up to 10⁵ particles per minute into the template, where they self-assemble based on DLVO (Derjaguin-Landau-Verwey-Overbeek) interactions balanced against hydrodynamic drag.
• Post-Processing: Oxygen plasma or solvents dissolve the polymer scaffold, yielding a free-standing structure stabilized by van der Waals forces. Optional annealing enhances bonding.

This process achieves assembly rates of 700 µm³/s with nanoscale resolution, tunable via laser power, scan speed, ionic strength, and surfactants.

NUS Researchers Driving the Innovation

Mingchao Zhang, Assistant Professor in NUS's Department of Materials Science and Engineering, serves as co-corresponding author, emphasizing his pivotal role in conceptualizing optofluidic interactions for confined 3D assembly. "The key idea is to manipulate optofluidic interactions precisely, guiding 3D assembly of various micro- or nanoparticles," Zhang noted. Shervin Bagheri, also from NUS Materials Science and Engineering, contributed to the interdisciplinary expertise blending fluid dynamics and materials.

First author Xianglong Lyu (formerly MPI-IS) and MPI-IS Director Metin Sitti round out the team, with Sitti hailing the method as overcoming 2PP's limitations for "tiny 3D objects from almost any material." This collaboration underscores NUS's growing global stature in cutting-edge research.Explore research positions at leading universities like NUS.

Showcasing the Technique: From Microcubes to Multimodal Microrobots

The paper demonstrates stunning versatility:

• Homogeneous Structures: SiO₂ microcubes, dangling croissants with 3D curved surfaces, helical threads (320 nm pitch), and even microscopic letters (855 nm height).
• Heterogeneous Assemblies: Site-selective integration of different materials, like separate 'P' and 'I' letters spaced 10 µm apart.
• Microfluidic Valves: Porous 3D channels sieve particles by size (e.g., separating 100 nm from 500 nm PLGA nanoparticles) in seconds via capillary action.
• Microrobots: L-shaped bots combining Fe₃O₄ (magnetic tumbling at 10 mT), TiO₂-Au (UV-driven propulsion), and Pt (catalytic in H₂O₂), enabling multimodal locomotion.

SEM images reveal flawless packing, with efficiencies boosted by surfactants like CTAB.

Applications Transforming Industries from Medicine to Robotics

In medicine, these microvalves could enable lab-on-a-chip diagnostics, sorting biomolecules or cells with pinpoint accuracy. Robotics benefits from hybrid microrobots navigating tight spaces—think swarms for targeted drug delivery or environmental sensing.

Microphotonics, catalysis, and energy devices stand to gain from materials like Au nanoparticles for plasmonics or WO₃ for photochromics. For Singapore's precision manufacturing ecosystem, this aligns with national priorities in advanced materials, potentially accelerating commercialization through NUS's AM.NUS Centre.Craft a standout CV for materials engineering roles.

Singapore's Higher Education Edge: NUS in Global Materials Innovation

NUS continues to lead Singapore's research landscape, building on prior feats like CHARM3D for self-healing electronics and nature-inspired alloys. This optofluidic breakthrough elevates the Department of Materials Science and Engineering, attracting top talent amid Asia's tech boom. With government backing via A*STAR and NRF grants, such innovations bolster Singapore's Smart Nation vision, fostering spin-offs in medtech and semiconductors.

Stakeholders praise the work: Industry partners eye scalable production, while academics highlight its pedagogical value for training next-gen engineers.Discover university opportunities in Singapore.

Advantages Over Existing Methods and Scalability Challenges

• Material Versatility: Unlike 2PP (polymers only), supports metals, oxides, quantum dots.
• Speed and Precision: 10⁵ particles/min vs. slow polymerization; nanoscale features via flow control.
• Multi-Material: Sequential rinsing enables layering without interference.
• Stability: Van der Waals + annealing yields robust, free-standing parts.

Challenges include optimizing for larger volumes and mitigating clogging via template design. Yet, simulations validate scalability.

Future Horizons: From Lab to Real-World Deployment

Looking ahead, the team envisions hybrid systems integrating optofluidics with other printing modalities for mass production. In Singapore, partnerships with local firms could yield prototypes within years, impacting healthcare robotics and sustainable manufacturing. Metin Sitti envisions "new frontiers for multifunctional micro-robots and micro-scale technology."

For aspiring researchers, NUS exemplifies how interdisciplinary collaboration drives impact—perfect for those eyeing PhDs or postdocs in nanofab.Browse postdoc openings in higher ed research.

Career Pathways in Singapore's Nanofab Boom

This publication spotlights opportunities in materials science at NUS and peers like NTU. Roles in R&D, from research assistants to faculty, demand skills in laser optics, colloid science, and simulation.Find research assistant jobs. Platforms like Rate My Professor offer insights into mentors like Prof. Zhang.

With Singapore's RIE2025 plan investing billions, now's the time to upskill via higher ed career advice.

Photo by Daniele Levis Pelusi on Unsplash

Why This Matters for Global Higher Education

NUS's feat reaffirms Asia's rise in STEM, inspiring universities worldwide. It equips students with tools for tomorrow's challenges, from climate-adaptive materials to AI-integrated devices. Stay ahead by exploring university jobs and higher ed jobs in this dynamic field.