3D Printing Tiny Structures Inside Living Cells

Researchers have, for the first time, developed a method to 3D-print microscopic structures directly inside living human cells by injecting a biocompatible photoresin and using two-photon polymerization with a laser to solidify it into detailed shapes like barcodes, geometric forms, and even a tiny 10-micrometer elephant; many of the cells not only survived this process but continued to live and divide, passing the embedded structure to daughter cells.

This early proof-of-concept breakthrough could pave the way for entirely new intracellular bioengineering tools and applications, such as tracking cells with internal barcodes, probing cellular mechanics, creating microscopic machines or sensors inside cells, and eventually enabling advanced capabilities like targeted drug delivery or engineered biological functions beyond what is possible with current techniques.

More information:

https://www.discovermagazine.com/a-3d-printed-elephant-inside-a-living-cell-signals-a-bioengineering-breakthrough-48730

Realistic Human Hand 3D-Printed from a Single Material

Researchers at the University of Texas at Austin, working with Sandia National Laboratories, have developed a novel 3D printing method called CRAFT (Crystallinity Regulation in Additive Fabrication of Thermoplastics) that lets a single inexpensive material be tuned at the pixel level to produce different mechanical and optical properties within one object. By precisely controlling light intensity during printing, CRAFT can make parts of an object hard and transparent while adjacent regions stay soft and flexible, mimicking the variety of textures found in real human tissues like skin, ligaments, tendons and bone.

Using this technique with a standard affordable 3D printer, the team successfully printed a realistic model of a human hand from one feedstock that captures these varying properties without needing multiple materials. This innovation could have significant practical applications, especially in medical training and education. Because traditional cadavers are costly, ethically complex to source, and don’t reflect the feel of real human tissue, CRAFT-printed models could offer a cheaper, more realistic alternative for students to practice on. Beyond medical use, the process may also be applied to making bioinspired materials for things like impact-absorbing gear or soundproofing.

More information:

https://interestingengineering.com/science/us-researchers-3d-print-realistic-human-hand

Knitting Machine Functions like a 3D Printer

A new prototype of a knitting machine creates solid, knitted shapes, adding stitches in any direction – forward, backward and diagonal – so users can construct a wide variety of shapes and add stiffness to different parts of the object.

Unlike traditional knitting, which yields a 2D sheet of stitches, this proof-of-concept machine – developed by researchers at Cornell and Carnegie Mellon University – functions more like a 3D printer, building up solid shapes with horizontal layers of stitches.

More information:

https://news.cornell.edu/stories/2025/11/knitting-machine-makes-solid-3d-objects

Gradient 3D Printed Designs

A new open-source software is shaking up the way engineers design and print multi-material objects. Created in the Matter Assembly Computation Lab, the tool enables engineers to design spatially varying multi-material objects with remarkable ease and precision.

The project reflects a growing interest in computational approaches that merge coding with design. The software allows users to combine complex mathematical functions and assign them as materials to different regions of a 3D object.

More information:

https://interestingengineering.com/innovation/openvcad-multi-material-3d-design

3D-printed tissue Mimics Real Organs

Surgeons and doctors often rely on artificial models to practice delicate procedures. Researchers at the University of Minnesota Twin Cities have developed a new 3D printing technique that creates lifelike human tissue structures. Their work could reshape surgical training by offering models that look, feel, and respond more like real human tissue.

The Minnesota team found a way to control the shape and size of microscopic patterns inside the printed material. Those patterns directly influence the strength and stretchiness of the tissues, giving them realistic mechanical properties. They also built a mathematical formula to predict how the tissues behave under stress.

More information:

https://interestingengineering.com/innovation/3d-printed-human-tissue-surgery-training

3D Printing Strings Together Dynamic Objects

While cable-driven mechanisms can create real-time motion to make an object bend, twist, or fold, they can be complicated and time-consuming to assemble by hand. To automate the process, researchers from MIT’s Computer Science and Artificial Intelligence Laboratory (CSAIL) have developed an all-in-one 3D printing approach called Xstrings. Part design tool, part fabrication method, Xstrings can embed all the pieces together and produce a cable-driven device, saving time when assembling bionic robots, creating art installations, or working on dynamic fashion designs.

Researchers used Xstrings to print a range of colorful and unique objects that included a red walking lizard robot, a purple wall sculpture that can open and close like a peacock’s tail, a white tentacle that curls around items, and a white claw that can ball up into a fist to grab objects. To fabricate these eye-catching mechanisms, Xstrings allows users to fully customize their designs in a software program, sending them to a multi-material 3D printer to bring that creation to life. You can automatically print all the device’s parts in their desired locations in one step, including the cables running through it and the joints that enable its intended motion.

More information:

https://news.mit.edu/2025/xstrings-3d-printing-strings-together-dynamic-objects-0318