Ablation Catheter

Ablation Catheter Manufacturers Race to the Micro

Smaller. Lighter. Innovative.

When talking to medical device designers about their product requirements, they often use these terms to explain their work. Of these, smaller has become an obsession for next-generation catheter designs.

The ability to micro-mold plastics and access tiny electronics are important for making things smaller. But fluid dispensing systems are actually leading the way for the next generation of ablation catheter technology.

Industry Drivers

Medical device manufacturers have good reasons for making their products smaller. Smaller devices require less space for storage and transportation.

Perhaps more importantly, micro technology promises lower costs through less intrusive and invasive procedures. This means there is less time necessary for recovery, therefore reduced hospital stays.

Less invasive surgical procedures offer many benefits, including:

• Less surgery trauma

• Lower post operation risks

• Fewer patient clinical visits

The push towards micro in the medical device industry is also a significant economic opportunity. In 2019, the global market reached a value of $20.5 billion, and experts expect it to grow to over $44 billion by 2030.

As the industry is moving towards smaller devices, ablation catheter manufacturers are leading the way in their use of micro dispensing technology.

What is an Ablation Catheter?

Catheter ablation is a minimally invasive treatment for fast heartbeats, whose medical term is cardiac arrhythmia. A catheter is a thin tube inserted through a blood vessel to the patient’s heart. Ablation is a technique used to strategically destroy abnormal tissue and restore proper function to the heart.

Ablation is a technique used to strategically destroy abnormal tissue and restore proper function to the heart.

Fluid Characteristics for Micro Dispensing

The variety of fluids and fluid viscosities that can be micro-dispensed spans a considerable range, encompassing:

• Adhesives

• Epoxies

• Ester

• Flux

• Greases

• Lacquers

• Oils

• Silicones

• Solder paste

• Weak acids

• Weak alkalis

There are many formulations of fluids from varied suppliers, each specially formulated for different application techniques.

First, and foremost, the fluid to be dispensed must readily flow through the dispensing heads. Viscosity is the resistance of a fluid to flow and is one of the primary rheologic properties used to determine if a fluid is dispensable.

Then, once the fluid reaches the substrate, it must have the ability to restructure and recover to keep it from spreading and contaminating the other components on the substrate.

The property of the fluid that allows the material to return to its original viscosity is part of the thixotropy of the fluid – the condition of the fluid becoming less viscous when subjected to an applied stress.

Understanding the thixotropy of fluids to be dispensed is a critical component in successful micro-dispensing.

Other properties of the fluid rheology that must be considered for micro-dispensing include:

• Density and weight

• Whether or not it has abrasive fillers

• Whether it is safe to dispense or combustible

The fluid properties can also be modified by the dispensing process being used. Heating of the air within the dispensing system can change the viscosity of the fluid, as can the fluid pressure and line speed.

The way the fluid is stored also influences its rheology. Is it kept in cold storage? How is it warmed? The properties of a fluid change as temperatures change, and as it expires.

Specifying different fluids and determining the best dispensing parameters for a specific application are important factors for implementing a successful micro-dispensing process.

Micro-Dispensing Trends for Catheter Technologies

Today’s catheters designs are pushing the boundaries of material and manufacturing capabilities. A modern catheter, once 2 mm in diameter, is now 1 mm in diameter or smaller.

These are catheters that can deliver pacemakers into the body. In addition, they can offer stenting, valving, suturing, and pacing properties. These smaller sized devices benefit from being placed close to the area in the body where they work best.

To make micro engineered catheters work, manufacturers focus on capability, scalability, sustainability. They use rapid prototyping and micro molding technologies.

The key to a micro catheter is thin walls. Subassembly design plays a role, too. Making it all fit together is critical.

The dispensed microdots are 300 – 400 microns in diameter, which is roughly the thickness of five to six human hairs. To achieve these tiny deposit sizes, sophisticated fluid dispensing technologies are necessary.

Fluid Dispensing Solutions

Ablation catheter manufacturing relies on extremely precise fabrication technology. Fluid jetting solutions, such as the PICO® family of fluid jetting equipment adds value to precision catheter manufacturing.

PICO Jetting Systems for Ablation Catheter Production

The PICO Pµlse® XP jet valve and PICO® Toµch™ XP controller are ideal for ablation catheter manufacturing because they provide extreme precision and repeatability with a unique self-regulating calibration for improved valve-to-valve jetting performance.

Specifically, the micro deposit capability — as small as 0.5 nL — applied precisely at up to 1000Hz continuously enables organizations to get the precise control required for advanced medical device manufacturing. These capabilities, coupled with micron (µm) level stroke adjustment, are ideal for sophisticated non-contact applications like advanced cardiac catheter manufacturing.

The PICO Pµlse XP provides very accurate jet dispensing for applications like ablation catheter manufacturing that require consistency and extremely accurate fluid placement.

Contact Valve Solutions for Catheter Production

Needle valves are an essential tool for putting fine dispensing fluid lines and dots onto substrates. Ablation catheter manufacturing frequently requires microdots as small as 150 µm (0.15 mm) (0.006") diameter. The xQR41 MicroDot™ valves enable dispensing in tight spaces at more complex angles.

These contact valves are different from non-contact valves like PICO jet dispensing systems because they must come in contact with the dispensing surface to apply a fluid. This makes them slower than jetting systems, but not less reliable or accurate.

xQR41 MicroDot valves enable dispensing in tight spaces at more complex angle

For applications requiring deposits down to the fractions of a microliter, the 741MD MicroDot valves offer pneumatical operation and control. For the right manufacturing application, catheter fabricators select this solution because it dispenses consistent microdots as small as 0.18 mm (0.007”) diameter, it is unaffected by entrapped air in fluids, and offers drip-free shutoff.

Ideal for micro spraying needs, the 787MS MicroSpray valves are a popular choice for ablation catheter manufacturers. That’s because small gauge standard spray valves can apply a precise, uniform spray pattern up to 30% smaller than standard spray valves. The valve makes spray patterns as small as 3.3 mm (0.13”) and as great as 19 mm (0.75”) in diameter.

Likewise, the 781Mini Spray valves also provides the kind of precision required for ablation catheter manufacturing. The spray valve provides spray control in patterns as narrow as 1 mm (0.04”) wide. It offers uniform spray patterns, better accuracy and edge definition.

The 787MS MicroSpray makes fluid spray patterns as small as 3.3 mm (0.13”) and as great as 19 mm (0.75”) in diameter.

Hand-Held Fluid Dispensing Solutions for Catheter Production

Automating the precise movements necessary to build an advanced ablation catheter is oftentimes impossible. Many highly skilled people perform the extremely precise movements necessary on these small workpieces.

To apply dispensing fluids manually, the UltimusPlus™ is a popular solution. The UltimusPlus I-II dispensers provide a simplified setup and operation with advanced touchscreen control of dispensing parameters.

Nordson EFD handheld fluid dispensing solutions enable operators to perform the intricate and precise movements necessary to build sophisticated ablation catheters.

To meet the need for fine lines and dots, manufacturers use 33 ga Optimum Chamfered Tips. The chamfered tips are ideal for dispensing between delicate surfaces or making exact, repeatable micro-deposits.

In the 33-ga size, the tips are capable of consistently making a 0.10 mm / 0.004" line of dispensed fluids. When paired with the Optimum syringe barrels, the product offers the purity, contamination-free, and static-free performance necessary for medical device manufacturing.

Micro Dispensing Production Challenges

As engineers find success with new ablation catheter designs, other areas of the life sciences industry are looking to mirror those triumphs. It's common to see smaller implantable devices for managing heart rhythm, pain, and blood pressure.

What they share with ablation catheter manufacturing is the ongoing challenge to make ever smaller fluid deposits. For these innovative applications, the requirement is for nanoliter and smaller deposit sizes. This is a significant change in manufacturing, moving from microliters to nanoliters, with deposit sizes specifically at 4 nanoliters.

Dispense tips in the 32 or 33 ga size enable manufacturers to reliably deposit fluids for applications that require micro dispensing, with a stainless-steel ceramic microdot dispense tips available in a 37 ga size for tight tolerance micro-dispensing.

Jetting offers new manufacturing opportunities, but proven contact fluid dispensing remains a viable and popular manufacturing option. Contact dispensing uses surface tension properties to make repeatable and accurate deposits.

In its most basic form, contact dispensing releases a dot of fluid that forms a tiny droplet at the end of the tip. Surface tension keeps the dot in a consistent shape, and the dot is released on the substrate by contact.

While this is a proven and popular approach, it does have limitations. One reason is that the surface tension of each fluid affects the size of droplets. Also, the substrate’s characteristics impact droplet size. Additionally, contact dispensing requires that manufacturers are extremely precise on the Z placement of the X, Y, Z axis.

For designs that require fine lines and dots, jetting can provide an excellent manufacturing solution. Jetting eliminates assembly fluid surface tension challenges. Since jetting supplies the application force, there is no surface tension.

The Future of Micro Dispensing

The era of micro dispensing has begun. Who, how, and what segments of the life sciences industry choose to leverage this fluid dispensing technology is still to be determined, however.

The bigger picture for manufacturing medical devices like catheters is clearer, though. As global demand continues to grow, more efficient manufacturing solutions are necessary. Automated systems need micro fluid dispensing capabilities to keep up with demand.

Micro applications require more repeatable processes with faster cycle times.

Specific to ablation catheter manufacturing, successful future micro technology fabrication requires bonding electrodes, and making strategic positioning of solder pastes. Using epoxy paste to protect electronic parts and handling them can be a difficult task that needs to be addressed. Catheter makers need reliable solutions to put micro amounts of fluid onto a surface repeatedly.

Conclusion

The race to the micro is here, and it is only accelerating. Companies like Nordson EFD have developed technology to help industries like ablation catheters succeed by making fluid deposits smaller. They need to keep making deposits even smaller.

There is a strong effort to make smaller, more specialized catheters. Advances in jetting technology will make minimally invasive specialty catheters possible. In the future, precise technologies for dispensing small lines and dots at the micron level will be crucial. These technologies will determine future outcomes.