PUMCH and Tsinghua Develop Novel Protein Coating to Solve Ureteral Stent Encrustation and Infection

Peking Union Medical College Hospital (PUMCH) has achieved a significant breakthrough in urological medical devices through collaborative research with Tsinghua University. The team has developed an innovative protein coating technology using natural intrinsically disordered protein condensates, creating an intelligent hydrophilic protective membrane that effectively addresses the persistent clinical challenges of ureteral stent encrustation and infection.

Table of Contents

• The Clinical Challenge of Ureteral Stents
• Medical-Engineering Innovation: Natural Disordered Protein Condensates
• Mechanism of the Intelligent Hydrophilic Protective Membrane
• Clinical Significance and Research Value
• Research Team and Medical-Engineering Integration
• Future Prospects
• Sources

The Clinical Challenge of Ureteral Stents

Ureteral stents are essential medical devices used to maintain urinary tract patency in patients with ureteral obstruction, kidney stones, and post-surgical recovery. Globally, approximately 1.5 million ureteral stents are implanted annually, serving as a cornerstone of modern urological practice.

Despite their widespread use, conventional ureteral stents face significant clinical complications. Studies indicate that up to 80% of patients experience stent-related complications, with the following breakdown:

• Encrustation (30.2%): Mineral deposits form on the stent surface, leading to blockage and reduced patency
• Infection (10.1%): Bacterial colonization and biofilm formation increase the risk of urinary tract infections
• Displacement (5.6%): Stent migration from the intended position requiring re-intervention
• Restenosis (14.3%): Re-narrowing of the ureter after stent removal

These complications not only cause significant patient discomfort but also increase healthcare costs due to additional procedures, prolonged hospital stays, and antibiotic treatments. The development of a coating technology that can simultaneously address multiple complications has been a long-standing goal in the field.

Medical-Engineering Innovation: Natural Disordered Protein Condensates

The research team, led by experts from PUMCH’s Department of Urology and Tsinghua University’s Department of Chemistry, discovered that intrinsically disordered proteins (IDPs) offer unique properties ideal for medical device coatings.

FUS Protein’s Intrinsically Disordered Functional Region (IDPFUS)

The researchers focused on the FUS protein, specifically its intrinsically disordered functional region (IDPFUS). Unlike traditional proteins with fixed three-dimensional structures, IDPFUS exhibits the following characteristics:

• No fixed 3D structure: The protein chain remains flexible and dynamic, allowing for spontaneous molecular organization
• Spontaneous condensation: Under physiological conditions, IDPFUS naturally forms liquid-like condensates through phase separation
• Adaptive surface properties: The condensates create a hydrophilic, biocompatible interface

This natural phenomenon of protein condensate formation provides an elegant solution for creating uniform, stable coatings on medical device surfaces without the need for complex synthetic chemistry or harsh processing conditions.

Mechanism of the Intelligent Hydrophilic Protective Membrane

Polydopamine-Mediated Two-Step Covalent Grafting

The research team developed a polydopamine-mediated two-step covalent grafting technique to securely attach the protein condensates to the stent surface:

1. First step: Polydopamine is deposited onto the stent surface, creating an adhesive intermediate layer with abundant functional groups
2. Second step: IDPFUS condensates are covalently grafted to the polydopamine layer, forming a stable, uniform coating

Four Key Protective Mechanisms

The intelligent hydrophilic protective membrane provides comprehensive protection through four integrated mechanisms:

1. Hydrophilic Barrier Effect

   • Creates a highly hydrated surface that repels protein adhesion and bacterial attachment
   • Reduces friction during stent insertion and removal
   • Maintains surface properties throughout the implantation period

2. Anti-Encrustation Properties

   • Inhibits crystal nucleation and growth on the stent surface
   • Prevents calcium oxalate and calcium phosphate deposition
   • Significantly reduces the risk of stent blockage

3. Anti-Infection Capability

   • Resists bacterial adhesion and biofilm formation
   • Reduces the incidence of catheter-associated urinary tract infections (CAUTIs)
   • Potentially decreases antibiotic usage and related complications

4. Long-term Stability

   • Covalent bonding ensures coating durability throughout the typical stent indwelling period
   • Maintains protective function under dynamic urinary flow conditions
   • Resists degradation from urinary enzymes and pH fluctuations

Clinical Significance and Research Value

This breakthrough technology addresses multiple critical needs in urological care:

For Patients:

• Reduced stent-related complications and associated discomfort
• Fewer follow-up procedures and hospital visits
• Improved quality of life during stent indwelling period
• Lower risk of antibiotic-resistant infections

For Healthcare Systems:

• Decreased overall treatment costs due to fewer complications
• Reduced need for stent exchange procedures
• Lower antibiotic consumption and associated resistance development
• Shorter hospital stays and recovery times

The research demonstrates the potential of applying natural biomaterials to medical device engineering, opening new avenues for developing next-generation implantable devices with enhanced biocompatibility and functionality.

Research Team and Medical-Engineering Integration

This project exemplifies the successful integration of clinical medicine and engineering disciplines:

• PUMCH Department of Urology: Provided clinical insights, identified unmet needs, and contributed to experimental design and validation
• Tsinghua University Department of Chemistry: Brought expertise in protein chemistry, material science, and surface engineering

The collaboration demonstrates how medical-engineering partnerships can accelerate the translation of fundamental scientific discoveries into clinically applicable solutions. The team’s approach of using naturally occurring proteins as coating materials represents a paradigm shift from traditional synthetic polymer coatings.

Future Prospects

The research team has outlined several directions for continued development:

1. Clinical Trials: Designing and conducting multicenter clinical trials to validate safety and efficacy in human patients

2. Technology Optimization: Further refining coating parameters to maximize protective effects while ensuring manufacturing scalability

3. Expanded Applications: Investigating the potential application of the protein coating technology to other medical devices, such as catheters, guidewires, and other urological instruments

4. Technology Transfer and Commercialization: Working with industry partners to scale up production and bring the technology to market

5. Regulatory Approval: Pursuing regulatory clearance from the National Medical Products Administration (NMPA) and international regulatory bodies

Sources

1. PUMCH Urology Department Research Publications
2. Tsinghua University Department of Chemistry Research Archive
3. Clinical studies on ureteral stent complications
4. National Medical Products Administration guidelines