Irreversibly Softened IV Needles

Intravenous (IV) injection is a commonly used method for treating patients around the world because it works quickly and allows treatment to be delivered continuously by injecting the drug directly into the blood vessel. However, medical IV needles are made of hard materials such as stainless steel or plastic, which are mechanically incompatible with the body’s soft biological tissue and can cause serious problems in healthcare settings, ranging from minor tissue damage at the injection site to severe inflammation.

The structure and flexibility of rigid medical intravenous infusion equipment also leads to the unethical reuse of needles to reduce the cost of injections, leading to the spread of deadly blood-borne infections such as human immunodeficiency virus (HIV) and hepatitis B/C viruses . Additionally, accidental needle stick injuries occur frequently in healthcare settings around the world and are a viable source of such infections, with intravenous needles being the most likely vectors for infectious disease. For these reasons, and following a significant increase in the number of deadly infectious diseases, the World Health Organization (WHO) launched a policy on safe injection practices in 2015, encouraging the development and use of “smart” syringes with features that prevent reuse due to medical sharps Worldwide diseases caused by related problems.

The Korea Advanced Institute of Science and Technology announced on the 13th that Professor Jae-Woong Jeong of the School of Electrical Engineering and his research team successfully developed a phase-converting, adaptive and non-reusable (P-CARE) needle with variable stiffness, which can improve patient health and ensure The safety of medical personnel is ensured through integrated joint research with another team led by Professor Zheng Yuanyi of the Graduate School of Medicine.

The new technology is expected to allow patients to move without worrying about pain at the injection site, as it reduces the risk of damage to blood vessel walls when patients receive intravenous drugs. This is achieved through the needle’s adjustable stiffness feature, which will allow it to become soft and elastic due to increased temperature when inserted into the body to accommodate the movement of the thin-walled vein. It is also expected to prevent blood-borne disease infections caused by accidental needlestick injuries or unethical reuse of syringes, because the deformed needle remains permanently soft even after being retracted from the injection site.

Karen-Christian Agno, a doctoral researcher in the School of Electrical Engineering, and Dr. Keungmo Yang in the Graduate School of Medicine participated as co-first authors. The research results were published in Nature Biomedical Engineering October 30th. (Paper title: Temperature-responsive intravenous needle that irreversibly softens upon insertion)

< 图 1. 一次性可变硬度静脉针。 (a) P-CARE 针的主要特征的概念图，其机械性能可通过体温改变，(b) 常用静脉通路装置和 P-CARE 针的照片，(c) 常见静脉通路的性能设备和 P-CARE 针 >

“We developed this special needle using advanced materials and micro/nano engineering technology, which can solve many global problems associated with conventional medical needles used in healthcare around the world,” said Dr. Jae-Woong Jeong, associate professor of electrical engineering at KAIST , is also the study’s lead senior author.

The softened IV needle created by the research team is made from liquid metal gallium, forming a hollow mechanical needle frame encapsulated in an ultra-soft silicone material. In the solid state, gallium is hard enough to penetrate soft biological tissue. However, gallium melts when exposed to body temperature during insertion, turning it into a pliable state like the surrounding tissue, allowing for stable drug delivery without damaging blood vessels. Once used, due to the supercooling phenomenon of gallium, the needle remains soft even at room temperature, fundamentally preventing needle stick accidents and reuse problems.

The biocompatibility of the softened intravenous needle was verified through in vivo mouse studies. Studies have shown that implanted needles cause significantly less inflammation than similarly sized standard IV devices made of metal needles or plastic catheters. The study also confirmed that the new needle was able to deliver the drug as reliably as commercial injection needles.

< 照片1.随体温软化的P-CARE针的照片。 >

The researchers also demonstrated the possibility of integrating a custom ultrathin temperature sensor with a softened intravenous needle to measure temperature in the field to further improve patient health. A single component of the sensing needle device can be used to monitor core body temperature and even detect fluid leakage on-site when used in-dwelling, without the need for additional medical tools or procedures, providing better health care services for patients.

The researchers believe this transformative IV needle could open up new opportunities for a wide range of applications, particularly in clinical settings where other medical needles and sharp medical tools can be redesigned to reduce muscle tissue damage during indwelling use. According to a 2018 World Health Organization report, an estimated 16 billion medical injections are performed worldwide each year, but not all needles are properly disposed of, so softened IV needles may become even more valuable in this day and age.

< 图 2. P-CARE 针的生物相容性测试：H&E 染色组织学图像（左侧虚线框内的区域在右侧放大视图中提供）、TUNEL 染色（绿色）、细胞核 DAPI 染色（蓝色） ）以及来自不同器官的肌肉组织的共染色（TUNEL 和 DAPI）。 >

< 图 3. 与温度传感器集成的 P-CARE 针的温度监测功能的潜在用途的概念图。 >

(a) Schematic diagram of intravenous drug injection into the abdomen of laboratory mice (b) Changes in body temperature during drug injection (c) Conceptual diagram of normal intravenous drug injection (top) and fluid leakage (bottom) (d) Normal injection of drugs and fluids Body temperature comparison during leakage: When liquid leakage occurs due to incorrect insertion, a sudden drop in temperature is detected.

This work was supported by a grant from the National Research Foundation of Korea (NRF) funded by the Ministry of Science and ICT.