YUHONG GROUP - Knowledge of stainless steel medical syringes

Stainless steel medical syringe is a widely used instrument in the medical field, and its core material is medical grade stainless steel (such as austenitic stainless steel or martensitic stainless steel such as 304, 316L). The following is a detailed description of its features, uses and technical details:

I. Core features
1. Excellent corrosion resistance
- Adding chromium (Cr), nickel (Ni), molybdenum (Mo) and other alloying elements to form a passivation film to resist corrosion from body fluids and disinfectants (e.g., alcohol, ethylene oxide), avoiding the precipitation of metal ions.
- 316L stainless steel because of the molybdenum content, more resistant to chloride corrosion, suitable for long-term implantation or high osmotic solution contact scenarios.
2. High strength and rigidity
- Martensitic stainless steel (e.g. 420) is quenched and tempered to a hardness of 50-60 HRC, ensuring that the syringe is not easily bent or broken during puncture.
- Wall thickness can be precisely controlled to less than 0.1mm, taking into account the strength of the hollow structure and the consistency of the inner diameter.
3. Biocompatibility certification
- Comply with ISO 9626 (medical syringe standard) and ISO 10993 biocompatibility test (cytotoxicity, sensitisation, haemolysis, etc.) to ensure safe contact with human tissue.
4. Precision processing technology
- Laser cutting or mechanical drawing process is adopted, and the tip of the needle adopts three-pronged or five-bevelled grinding technology (e.g. Terumo's Pencil Point design), which reduces puncture resistance and tissue damage.
- The internal lumen is mirror-polished (Ra ≤ 0.2μm) to reduce the risk of drug residue and bacterial adhesion.
5. Sterilisation adaptability
- Resistant to autoclaving (121℃-135℃), gamma irradiation or EO sterilisation, supporting reuse (subject to local regulations, most countries are restricted to single-use).

II. Main uses
1. Clinical treatment
- Injection: subcutaneous, intramuscular, intravenous injection (such as insulin pen needles, vaccine syringes).
- Blood collection: vacuum blood collection tube with needle (21-23G), to achieve low haemolysis sampling.
- Infusion: indwelling needle catheter (e.g. Y-needle) with infusion pump for precise drug delivery.
- Anaesthesia: Epidural anaesthesia needle (Tuohy needle) with side hole design for easy catheter introduction.
2. Minimally invasive surgery
- Biopsy Needle: e.g. Tru-Core Bone Biopsy Needle, hollow structure for obtaining tissue samples.
- Interventional catheter guidewire: Used as a conduit for vascular interventions (e.g. Seldinger technique).
- Radiofrequency ablation electrodes: Stainless steel needles are used as electrode carriers to deliver high-frequency currents.
3. Laboratory and Pharmaceutical
- Chromatography: HPLC feeding needle, resistant to organic solvent corrosion (e.g. acetonitrile, methanol).
- Cell culture: micro-sampling needles (e.g. Hamilton products), precision up to μL level.
- Drug filling: aseptic filling needles, in line with GMP clean room requirements.
4. Special Scenarios
- Veterinary medicine: large calibre syringes (e.g. 16G) designed for animal blood vessel size.
- Aesthetic field: Microneedle roller (0.5mm needle length) for transdermal drug delivery or collagen induction.

III. Technology development trend
- Material upgrading: titanium nitride coated syringes (reducing puncture friction by 30%), Nitinol superelastic needles (suitable for curved vessels).
- Intelligent: Integrated pressure sensor needle (real-time monitoring of puncture resistance), or navigation syringe combined with ultrasound probe.
- Eco-friendly design: removable needle holder design for easy sorting and recycling of stainless steel parts to reduce medical waste pollution.