Researchers headed by a team at the California Institute of Technology developed an ultrasound-guided 3D printing technique that could make it possible to fabricate medical implants in vivo and deliver tailored therapies to tissues deep inside the body—all without invasive surgery. The researchers say the imaging-guided deep tissue in vivo sound printing (DISP) platform utilizes low-temperature–sensitive liposomes (LTSLs) as carriers for cross-linking agents, enabling precise, controlled in situ fabrication of biomaterials within deep tissues.
Reporting on their development in Science “Imaging-guided deep tissue in vivo sound printing”, first author Elham Davoodi, PhD, and senior, corresponding author Wei Gao, PhD, described proof of concept studies demonstrating in vivo printing within the bladders and muscles of mice, and rabbits, respectively. Gas vesicle (GV)–based ultrasound imaging integrated into the printing platform enabled real-time monitoring of the printing process and precise positioning. In their paper, the authors concluded, “DISP’s ability to print conductive, drug-loaded, cell-laden, and bioadhesive biomaterials demonstrates its versatility for diverse biomedical applications.”
Three-dimensional (3D) bioprinting technologies offer significant promise to modern medicine by enabling the creation of customized implants, intricate medical devices, and engineered tissues, tailored to individual patients, the authors wrote. “However, the implantation of these constructs often requires invasive surgeries, limiting their utility for minimally invasive treatments.”
While in vivo bioprinting—“3D printing” tissue directly within the body—offers a less invasive alternative, it has been limited by challenges such as poor tissue penetration depth, a narrow range of biocompatible bioinks, and the need for printing systems that operate at high resolution with precise, real-time control. “Although near-infrared (NIR) light has been explored as a biosafe energy source for in vivo printing, its applications remain restricted to subcutaneous tissues due to limited light penetration,” the team continued.
To address these barriers, Davoodi and colleagues developed a novel imaging-guided platform, imaging-guided DISP, which uses focused ultrasound and ultrasound-responsive bioinks to precisely fabricate biomaterials directly within the body. These bioinks, or US-inks, combine biopolymers, imaging contrast agents, and temperature-sensitive liposomes carrying crosslinking agents and can be delivered to targeted tissue sites deep within the body via injection or catheter. “US-inks are composed of biopolymers, cross-linking agent-encapsulated LTSLs, and GVs that act as ultrasound imaging contrast agents,” the team further explained. “These bioinks are delivered to the target sites through injection or catheters and are located using an ultrasound imaging setup integrated into a 3D printing platform.”
A focused ultrasound (FUS) transducer, guided by automated positioning and a predefined digital blueprint, triggers localized low-temperature heating (slightly above body temperature) that releases the crosslinker, initiating immediate in situ gel formation. “Localized heating induced by FUS triggers the release of cross-linking agent from the LTSLs, enabling immediate in situ cross-linking of the US-ink.” The bioinks and their resulting gels can be tailored for various functions, including conductivity, localized drug delivery, and tissue adhesion, as well as real-time imaging capabilities.
Davoodi and colleagues validated the DISP technology by successfully printing drug-loaded and functional biomaterials near cancerous sites in a mouse bladder and also deep within rabbit muscle tissue, demonstrating potential applications for drug delivery, tissue regeneration, and bioelectronics. “We validated DISP by successfully printing near diseased areas in the mouse bladder and deep within rabbit leg muscles in vivo, demonstrating its potential for localized drug delivery and tissue replacement,” the team stated.
Further biocompatibility tests revealed no signs of tissue damage or inflammation, and the body cleared unpolymerized US-ink within a week, illustrating the platform’s safety. “The DISP technology offers a versatile platform for printing a wide range of functional biomaterials, unlocking applications in bioelectronics, drug delivery, tissue engineering, wound sealing, and beyond,” the team stated. “By enabling precise control over material properties and spatial resolution, DISP is ideal for creating functional structures and patterns directly within living tissues.”
In a related perspective, Xiao Kuang, PhD, at the University of Wisconsin-Madison, wrote, “Although Davoodi et al. advanced ultrasound 3D printing toward clinical translation, additional refinements are needed to implement the technology for clinical use … A detailed relationship between process conditions, the structure of the printed material, and the resulting properties must be elucidated through careful testing.”
The post In Vivo Bioprinting Shows Promise for 3D Printed Implants Without Surgery appeared first on GEN - Genetic Engineering and Biotechnology News.
Reporting on their development in Science “Imaging-guided deep tissue in vivo sound printing”, first author Elham Davoodi, PhD, and senior, corresponding author Wei Gao, PhD, described proof of concept studies demonstrating in vivo printing within the bladders and muscles of mice, and rabbits, respectively. Gas vesicle (GV)–based ultrasound imaging integrated into the printing platform enabled real-time monitoring of the printing process and precise positioning. In their paper, the authors concluded, “DISP’s ability to print conductive, drug-loaded, cell-laden, and bioadhesive biomaterials demonstrates its versatility for diverse biomedical applications.”
Three-dimensional (3D) bioprinting technologies offer significant promise to modern medicine by enabling the creation of customized implants, intricate medical devices, and engineered tissues, tailored to individual patients, the authors wrote. “However, the implantation of these constructs often requires invasive surgeries, limiting their utility for minimally invasive treatments.”
While in vivo bioprinting—“3D printing” tissue directly within the body—offers a less invasive alternative, it has been limited by challenges such as poor tissue penetration depth, a narrow range of biocompatible bioinks, and the need for printing systems that operate at high resolution with precise, real-time control. “Although near-infrared (NIR) light has been explored as a biosafe energy source for in vivo printing, its applications remain restricted to subcutaneous tissues due to limited light penetration,” the team continued.
To address these barriers, Davoodi and colleagues developed a novel imaging-guided platform, imaging-guided DISP, which uses focused ultrasound and ultrasound-responsive bioinks to precisely fabricate biomaterials directly within the body. These bioinks, or US-inks, combine biopolymers, imaging contrast agents, and temperature-sensitive liposomes carrying crosslinking agents and can be delivered to targeted tissue sites deep within the body via injection or catheter. “US-inks are composed of biopolymers, cross-linking agent-encapsulated LTSLs, and GVs that act as ultrasound imaging contrast agents,” the team further explained. “These bioinks are delivered to the target sites through injection or catheters and are located using an ultrasound imaging setup integrated into a 3D printing platform.”
A focused ultrasound (FUS) transducer, guided by automated positioning and a predefined digital blueprint, triggers localized low-temperature heating (slightly above body temperature) that releases the crosslinker, initiating immediate in situ gel formation. “Localized heating induced by FUS triggers the release of cross-linking agent from the LTSLs, enabling immediate in situ cross-linking of the US-ink.” The bioinks and their resulting gels can be tailored for various functions, including conductivity, localized drug delivery, and tissue adhesion, as well as real-time imaging capabilities.
Davoodi and colleagues validated the DISP technology by successfully printing drug-loaded and functional biomaterials near cancerous sites in a mouse bladder and also deep within rabbit muscle tissue, demonstrating potential applications for drug delivery, tissue regeneration, and bioelectronics. “We validated DISP by successfully printing near diseased areas in the mouse bladder and deep within rabbit leg muscles in vivo, demonstrating its potential for localized drug delivery and tissue replacement,” the team stated.
Further biocompatibility tests revealed no signs of tissue damage or inflammation, and the body cleared unpolymerized US-ink within a week, illustrating the platform’s safety. “The DISP technology offers a versatile platform for printing a wide range of functional biomaterials, unlocking applications in bioelectronics, drug delivery, tissue engineering, wound sealing, and beyond,” the team stated. “By enabling precise control over material properties and spatial resolution, DISP is ideal for creating functional structures and patterns directly within living tissues.”
In a related perspective, Xiao Kuang, PhD, at the University of Wisconsin-Madison, wrote, “Although Davoodi et al. advanced ultrasound 3D printing toward clinical translation, additional refinements are needed to implement the technology for clinical use … A detailed relationship between process conditions, the structure of the printed material, and the resulting properties must be elucidated through careful testing.”
The post In Vivo Bioprinting Shows Promise for 3D Printed Implants Without Surgery appeared first on GEN - Genetic Engineering and Biotechnology News.