Traditionally, bone implants used in surgeries have been made from various materials such as metals, donor bones, or, more recently, 3D-printed materials. The conventional approach necessitates careful pre-surgical planning, where implants must be customized and manufactured before a patient’s surgery. However, in cases involving complex or irregular bone fractures, this preparatory phase can be a significant challenge. In contrast, the new method allows for the direct creation of customizable bone scaffolds tailored to the specific anatomy of the patient, right at the site of injury, eliminating the need for any preoperative fabrication.

Jung Seung Lee, an associate professor of biomedical engineering at Sungkyunkwan University and a co-author of the study, highlights the advantages of this technology. “Our proposed technology offers a distinct approach by developing an in situ printing system that enables real-time fabrication and application. This innovative method allows for highly accurate anatomical matching, particularly beneficial during surgeries involving irregular or complex defects,” he stated. This real-time capability not only simplifies the process for surgeons but also enhances the overall quality of care patients receive during critical procedures.

The filament material powering this device contains two crucial components: hydroxyapatite (HA), a naturally occurring mineral component found in bone, known for promoting healing, and polycaprolactone (PCL), a biocompatible thermoplastic. PCL can be liquefied at temperatures as low as 60°C, allowing it to flow and conform seamlessly to the irregular shapes of fractured bone while remaining cool enough to prevent thermal injury to surrounding tissues during application. By modifying the proportion of HA to PCL in the filament, the research team can customize the strength and hardness of the grafts to match the varied anatomical requirements presented in patients.

The surgeon’s ability to manipulate the device manually grants them unprecedented control during the printing process. This capability ensures that the grafts can be accurately placed in precise orientations, directions, and depths according to the unique characteristics of the patient’s injury. Lee noted that the entire printing process could be completed in a matter of minutes, significantly reducing overall operative times. This efficiency becomes critical in surgical environments, where time limitations often dictate the quality of care in emergency situations.

One of the common pitfalls of surgical implants is the heightened risk of postoperative infections. Acknowledging this concern, the researchers ingeniously included two powerful antibacterial agents, vancomycin and gentamicin, into the filament material used for 3D printing the grafts. Experiments conducted both in petri dishes and liquid mediums have shown promising results, with the filament scaffolds effectively inhibiting the growth of notorious bacteria such as E. coli and Staphylococcus aureus. Notably, the release of these drugs is sustained, allowing them to diffuse directly to the surgical site over several weeks, thereby reducing the patient’s risk of infection without the drawbacks associated with systemic antibiotic use.

This localized delivery system is poised to bring significant clinical advantages. By minimizing the side effects and mitigating the risk of developing antibiotic resistance associated with broader systemic treatments, this innovative approach enables targeted protection against infections. Lee emphasizes the implications this could have for patients undergoing surgeries involving implants, where infection rates are a primary concern.

To demonstrate the efficacy of this technology, the research team conducted proof-of-concept tests on rabbits with severe femoral bone fractures. Remarkably, within 12 weeks of surgery, the results indicated no signs of infection or tissue necrosis. The implants demonstrated substantial bone regeneration compared to traditional bone cement, a common material utilized for addressing similar injuries in clinical settings.

The integrated scaffold is designed to carry out two functions: biological integration with the surrounding bone tissue and gradual degradation over time. Specifically, it is crafted to be substituted by newly formed bone as healing progresses. Lee and his team observed that in comparisons with previous grafts, their printed scaffolds yielded superior outcomes in essential structural metrics such as bone surface area and cortical thickness, correlating to improved healing and integration outcomes.

On the horizon, the research team plans to enhance the antibacterial properties of their 3D-printed scaffolds further and prepare for human clinical trials. Lee encapsulates the future vision succinctly: “For clinical adoption, our approach will first necessitate the development of standardized manufacturing protocols, validated sterilization procedures, and preclinical studies conducted in larger animal models to satisfy regulatory requirements.” If these benchmarks can be met successfully, the team is optimistic that this technology will transform bone repair practices directly within the operating room.

The innovative device represents a significant leap forward in medical technology, promising to alter how bone injuries are treated in real-time during surgical operations. As this research progresses and human trials commence, the potential for widespread clinical application could lead to higher success rates in bone repair, ultimately improving the quality of life for countless patients recovering from traumatic injuries.

This remarkable development serves as a true testament to the evolving landscape of biomedical engineering and the impact that interdisciplinary collaboration can have on improving patient outcomes in modern medicine.

Subject of Research: Animals
Article Title: In situ printing of biodegradable implant for healing critical-sized bone defect
News Publication Date: 5-Sep-2025
Web References: http://www.cell.com/device/home
References: 10.1016/j.device.2025.100873
Image Credits: Jeon et al. / Device

Keywords

Biomedical engineering, Additive manufacturing, Bone fractures, Traumatic injury, Bones, Medical technology, Regenerative medicine

The microneedle patch, which utilizes microneedles engineered to penetrate the top layers of skin, collects interstitial fluid – the fluid that surrounds cells in the dermal and epidermal layers. This interstitial fluid contains a wealth of biomarkers that correspond to those typically found in blood samples. Michael Daniele, a professor at NC State and a lead author of the study, emphasizes that utilizing interstitial fluid can streamline the biomarker testing process by eliminating the complexities associated with blood sample preparation.

During their proof-of-concept experiments, the researchers tested the patch on synthetic skin, demonstrating its ability to collect significant amounts of biomarkers within just 15 minutes. Moreover, the patch has been shown to store these samples for up to 24 hours, making it a versatile tool for patients and healthcare providers alike. An important biomarker monitored during testing was cortisol, a hormone that fluctuates with stress levels. The convenience of multiple readings without the pain and inconvenience of blood draws could revolutionize how individuals manage their stress and overall health.

The microneedle patch is made up of four distinct layers: a visible polymer housing, a gel layer, a paper layer for absorption, and the microneedles themselves. Designed to be completely passive, the patch harnesses the properties of the materials used to facilitate fluid transfer. The microneedles contain a material that swells upon contact with interstitial fluid, allowing the fluid to be drawn through the needle and into the paper layer. As the paper becomes saturated, it interfaces with the gel on the opposite side, which contains high concentrations of glycerol. This creates an osmotic pressure differential that facilitates further fluid movement, ultimately enhancing sample collection efficiency.

Dr. Daniele explains that the sample collected in the paper strip can be easily accessed for analysis once the patch is removed, further simplifying testing procedures. The researchers are not only leveraging this technology for cortisol tracking but also envision its application for a broader range of biomarkers found in interstitial fluid. The prospect of easy, pain-free monitoring opens significant avenues for conditions that require frequent testing and evaluation.

Additionally, the microneedle patch can be produced using affordable materials that are readily accessible, making the technology potentially cost-effective compared to traditional blood sample collection methods. Daniele notes, “The highest cost of the patches would be manufacturing the microneedles, but we think the price would be competitive with the costs associated with blood testing.” The elimination of needles, vials, and the need for trained professionals to draw blood presents a strong case for the widespread adoption of this innovative testing method.

The current phase of research includes human testing, with researchers ambitiously developing electronic devices capable of analyzing the samples collected by the microneedle patches. Thus far, a device has been successfully created to read cortisol levels directly from the patch’s paper strip, and efforts are underway to develop technologies for evaluating other biomarkers as well. The future holds promising potential for partnerships within the diagnostic industry to broaden the applications of this technology.

This self-powered microneedle patch represents a significant leap forward in health monitoring technology—a field that has often been stifled by reliance on invasive techniques. By providing a non-invasive alternative that is both efficient and accessible, this innovation could cater to an extensive range of health applications including stress management, chronic disease monitoring, and preventive healthcare measures.

While this technology is still in its infancy, the potential impact on personal health management could be profound. As researchers continue to refine the microneedle patch and explore its capabilities, it paves the way for a future where health monitoring is both comfortable and continuous, fostering an era of smarter, patient-centered healthcare solutions. This approach aligns with the future direction of medical technology, which increasingly emphasizes minimally invasive procedures aimed at enhancing patient comfort and accessibility.

The implications of this technology stretch beyond mere convenience; as health literacy and personal health monitoring become increasingly valued in contemporary society, the microneedle patch can empower individuals to take charge of their health by providing them with the ability to track important biometrics in a seamless fashion. This newfound autonomy could help trigger widespread changes in preventive healthcare and enhance overall public health outcomes over time.

As researchers in this field look for industry partners to bring their innovation to market, the global health community is poised to benefit from advancements like this, which can facilitate timely interventions and informed health decisions. The microneedle patch signifies a move toward the integration of technology in personal health, making monitoring easier and more attainable than ever before.

With continued support from funding agencies and a focus on exploration and development, the researchers at NC State are setting the stage for a technological revolution in health monitoring, one that could reshape our understanding of wellness and disease management. As they engage in human trials and refine the technology for broader applications, the microneedle patch holds the promise of a future where health monitoring can be performed effortlessly, delivering insights that can change lives.

This innovative research has been documented in the open-access paper titled “Design and Characterization of a Self-Powered Microneedle Microfluidic System for Interstitial Fluid Sampling,” published in the journal Lab on a Chip. The collaborative efforts of the researchers, combined with their entrepreneurial aspirations, suggest a future rich with potential for transformative health technologies that enhance the way we monitor and manage health.

Subject of Research: The development and testing of a self-powered microneedle patch for biomarker monitoring through interstitial fluid sampling.
Article Title: Design and Characterization of a Self-Powered Microneedle Microfluidic System for Interstitial Fluid Sampling
News Publication Date: August 1, 2025
Web References: Lab on a Chip Article
References: Not applicable
Image Credits: Michael Daniele, NC State University

Keywords

Non-invasive monitoring, microneedle patch, biomarkers, interstitial fluid, healthcare innovation, cortisol monitoring, chronic disease management, patient-centered technology.