Biomedical Textile Spotlight: Braiding Bioresorbables

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At Poly-Med, Inc., we focus on the design, development, and manufacturing of polymeric bioresorbable medical components, devices, and excipients. Our in-house vertically integrated system sets us apart from other competitors and makes us the LEADER OF BIORESORBABLES. We offer a wide variety of integrated solutions, including textile manufacturing of medical-grade braids. With our vertically integrated system, we are able to modify the polymer and yarn that are used to create the technical braid, and then alter the post-processing steps of the braid to yield the desired strength and mechanical parameters.

A common braided medical device is the absorbable suture; these sutures provide temporary support of a wound until the tissue is able to withstand normal physiological stresses. Over time, hydrolysis of the suture leads to the absorption of the implant coupled with the loss of mechanical strength followed by mass loss of the suture. Sutures can be manufactured through braiding, which produces intricate constructs that are created through the intertwining of multiple filaments or yarns forming a singular construct. Producing braided medical devices, such as sutures, is a well-established technique that allows for the structure and mechanical behaviors to be tailored to a targeted application. By changing the braiding pattern and process settings such as pick count, parameters such as strength, kink resistance, and torsion control, can be adjusted to modify the material’s performance.

One of the benefits of our vertical integration system is the ability to oversee the process from polymer through finished device. With our known catalog of polymers (https://www.poly-med.com/solutions/medical-polymers/), we have the ability to easily modify construct properties (strength and mass retention profiles) based on known chemistries. Additionally, we are able to perform custom extrusions to generate varying deniers, filament count, and tenacity.  Multifilaments are often used in braided sutures due to their excellent flexibility, handling properties, and greater knot strength compared to monofilaments. Additionally, coatings can be applied to braids to reduce surface roughness and tissue drag.  The manufacturing process of braiding is an ideal technique to develop bioresorbable sutures due to PMI’s ability to tailor braiding properties to meet the specific needs of medical applications. Contact us today to learn how we can help you with your next braided medical device!

Workhorse Polymers for Bioresorbable Device Development: Max-Prene® 955 and Dioxaprene® 100M

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Continuing the evolution of the bioresorbable medical device market has led to significant growth of the implantable device industry. When considering a bioabsorbable polymer to use for your specific device, many criteria should be considered based on the design requirements and desired functionality of the device’s intended use. Two (2) workhorse polymers that have endured the demand of multiple devices would be our Max-Prene® 955 and Dioxaprene® 100M. These polyester-based polymers have demonstrated their ability to support the need for the most demanding applications through their unique material properties.

Max-Prene® 955 is a fast-degrading, high strength, high stiffness polymer mainly comprised of glycolide with minor segments of  L-lactide. Attributable to its high glycolide content, Max-Prene® 955 allows for a faster crystallization than other glycolide/lactide copolymers, and permits improved processing (faster crystallizing time, higher modulus, and increased degradation profile). Our Max-Prene® 955 polymer typically exhibits strength loss in one to four weeks with complete mass loss occurring in approximately six (6) months (depending on processing format and anatomical location). The Max-Prene® 955 polymer can be processed for a variety of applications, including extruded articles, fiber extrusion (e.g., suture such as Vicryl®), textiles, molded applications, and 3D Printing.

Beyond Max-Prene® 955, Poly-Med offers its Dioxaprene® 100M (PDO linear homopolymer) that can also be processed into a variety of formats similar to applications listed above. Dioxaprene® 100M polymer has a lower initial modulus compared to Max-Prene® 955 and is best utilized for applications looking for extended strength retention, coupled with increased flexibility. PDO based-polymers, (e.g., PDS® II sutures), maintain strength for 4 – 6 weeks with complete mass loss occurring in approximately nine (9) months (depending on processing format and anatomical location).

When selecting a polymer to best fit your device’s need, consider one of the two workhorse polymers (Max-Prene® 955 or Dioxaprene® 100M), which continues to drive innovation in the bioresorbable medical device industry and contact us today to learn more!

Expectations of Working with Poly-Med, Inc.

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Poly-Med is the leader in bioresorbable polymers and customer solutions. We are a vertically integrated company that, thanks to our design and development approach, can design, develop, and manufacture absorbable medical textiles and custom components, providing an adaptable approach to customer needs for any medical application.

To support our development approach and provide support to our vertical integration business structure, Poly-Med, Inc. offers full in-house analytics. We have a vast array of in-house testing equipment that provide a quick and efficient turnaround on the assessment of our clients’ bioresorbable product properties.

There is more to Poly-Med than providing unparalleled expertise and an efficient, structured approach to custom solutions.

At Poly-Med, we try to always go beyond what is expected. All relationships, including and especially those with clients, involve expectations, and conflicts tend to occur when expectations are not met. Our goals are to make excellent impressions and exceed our clients’ basic expectations. We do so by being proactive, dependable, and understanding the importance of keeping commitments. Our clients trust us because they know we will properly develop and follow through on their strategies and support their product and their vision. In addition, we continuously deliver consistency: consistent quality, consistent results, consistent product.

In summary, you can expect:

– Unparalleled expertise
– Dependability
– Reliability
– Collaboration
– Responsiveness
– And, most importantly, we deliver the results.

If you are interested in developing a bioresorbable medical device and want a partner with experience, Contact us for more information!

AP Soliani Ph.D.

Standard Specifications for Surgical Mesh: A Review of FDA Guidance on Surgical Mesh Design

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On March 2, 1999, the U.S. Food and Drug Administration released a guidance document entitled Guidance for the Preparation of a Premarket Notification Application for a Surgical Mesh. Now in 2018, nearly 20 years later, it is still easy to become overwhelmed with everything required to prepare a new device for submission to the FDA. Guidance documents such as this one provide recommendations for the starting points of testing new devices and help alleviate some of the guesswork around what is required and what isn’t. Fortunately, partnering with a company like Poly-Med, with over 25 years of experience in bioresorbable materials and textiles, can help further navigate these waters.

This particular guidance document covers submission guidelines for surgical meshes in a wide variety of applications where a mesh product would be used to reinforce weakened soft tissue. These include area applications in abdominal wall repair (hernia repair), suture line/staple line reinforcement, muscle flap reinforcement, gastric banding, breast reconstruction, pelvic organ prolapse, and many more. For many of these applications, the current market trend is moving toward bioresorbable solutions, providing mechanical support throughout the healing process without permanent synthetic materials in the body. Poly-Med is the leader in bioresorbable textiles and has developed bioresorbable mesh products on the market for a wide variety of applications.

The FDA’s primary interest in any device review can usually be summarized in two words: safety and efficacy. Not surprisingly at all, the guidance document first focuses on the product being safe for human use. Likewise, this is usually a best first-step to consider in product development as future product development will all hinge on the materials as being safe for implantation. With this in this focus, the FDA requires the submission to include description of all material components in the device. This includes at minimum the sources/supplier and purity. To satisfy this requirement, material suppliers can provide reference to device master files (MAF), Certificate of Analysis (CoA), and Safety Data Sheets (SDS) with materials, all of which are noted to help simplify the review process. When considering the materials, special attention should be paid to any materials, reagents, or processing aids which are considered to be potentially cytotoxic, carcinogenic, or immunogenic. Additional testing may be required for any of these materials which are used to air in processing and may remain as residuals in the final material.

The next step in safety of an implantable device is consideration of sterilization. Applications are suggested to specify the method, validations, sterility assurance level (SAL, recommended SAL of 10-6), method for monitoring sterility, and packaging used to maintain sterility. Poly-Med uses several trusted partners with experience in sterilization to coordinate offering these services to our clients. Dependent on the type of material used and the desired processing plan, bioresorbable meshes can be sterilized using irradiation, ethylene oxide, or new emerging technologies such as nitrogen dioxide1.

While many of our materials are used in devices on the market and have proven biocompatibility, it is recommended that biocompatibility testing be conducted on final manufactured, sterilized, and packaged devices, as all can influence the final reaction in the body. While some provisions are allowed for products using the exact same material specifications as another similar device on the market, the guidance generally recommends that applications include testing in accordance to ISO-10993 for Cytotoxicity, Sensitization, Irritation or Intracutaneous Reactivity, Systemic Toxicity (acute), Genotoxicity, Implantation with histology of the surrounding tissue, Hemolysis, and Pyrogenicity. Given that most bioresorbable materials will leave some mass within the body for greater than 30 days, the FDA further recommends testing for Subchronic Toxicity and Chronic Toxicity. These tests should generally be conducted according to relevant USP Class VI and ASTM standards.

When using bioresorbable materials, part of the efficacy claim of a surgical mesh is its ability to degrade over time. In alignment with this guidance, Poly-Med often performs degradation studies for each device developed, being sure to take into account material selection, processing methods, as well as sterilization. Poly-Med is fully capable of conducting in-house in vitro degradation studies in both real and accelerated environments. Accelerated time points are used to quickly identify appropriate time points for a real time study and then evaluate device functionality and specifications at pre-determined time points. For surgical mesh devices, common strength loss tests are dependent on the application, and often include tensile strength, burst strength, suture pull-out strength, and tear resistance.

Though expiration dating is required for all surgical meshes, the need is especially apparent with bioresorbable materials. Many of these materials degrade with exposure to moisture, light, and/or heat, so packaging and sterilization methods can play a critical role in the ultimate shelf-life of the product. This guidance allows for expiration dating to be continuously updated over time without the need for a new 510k submission under the scope of Good Manufacturing Practice (GMP). This allows products to quickly enter the market and then slowly increase the expiration dates of new production as the real-time stability study continues.

If you are interested in developing a bioresorbable surgical mesh and want a partner with experience, Contact us for more information!

Andrew Hargett, M.S.

1 Lambert, B., et al. (2011). AAPS PharmSciTech, 12(4), pp. 1116-1126. doi: 10.1208/s12249-011-9644-8
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3225553/

Creating Structure Out of Chaos: Standardization for Fiber-Based Devices

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Poly-Med had the recent opportunity to present at an ASTM Workshop on the Characterization of Fiber-based Scaffolds and Devices in Manchester, NH at the Advanced Regenerative Manufacturing Institute (ARMI) https://www.armiusa.org/. The workshop was organized by ASTM International (http://www.astm.org), the National Institute of Standards and Technology (NIST) https://www.nist.gov/, and hosted by ARMI. The workshop featured seminar discussions from academia, clinicians, and included industrial spotlights on emerging technologies and application of fiber-based scaffolds and the promise they offer for regenerative medicine and medical device applications. Attendees of the workshop were able to discuss how fiber-based scaffolds are able to mimic the mechanics, architecture, and functionality of native tissues, while providing a temporary replacement for new cellular and tissue growth. A key focus of the event was the development of fiber-based scaffold characterization techniques to ensure consistency across facilities and uniformity in construct description and categorization.

Poly-Med presented on the importance of accurate and timely measures of critical release criteria for fiber-based scaffolds. Such criteria are required to ensure that high quality, safe, effective, and consistently reliable products are provided to clinicians. Poly-Med’s extensive work on fiber-based scaffolds and device examples spanned the use of technical textiles (warp knit, weft knit, and braided constructs), as well as the innovative technologies of electrospinning and additive manufacturing. Key areas of interest at this workshop included, image-based analysis approaches reviewing periodicity, porosity (void space), and diffusivity of fiber-based constructs. Method development and release testing were discussed along with batch-to-batch variations and the importance of establishing robust specifications that can be accurately, and reproducibly, measured.

Fiber-based scaffolding continues to be an ideal platform for tissue scaffolds and medical devices, yet still requires superior characterization to be fully utilized across emerging medical therapies. If you are interested in converting your lab-based scaffold into a robust medical device, be sure to contact Poly-Med to learn about our fiber-based methods (https://poly-med.com/solutions/medical-fibers-textiles and our in-house electrospinning capabilities (https://poly-med.com/solutions/regenerative-scaffolding/).

Seth McCullen, Ph.D.

Heat Setting and the Impact on Medical Textiles

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If you’ve ever woken up late for an important job interview or meeting, you’ve probably thrown on some clothes and looked in the mirror with horror at all of the wrinkles staring back at you. While ironing clothes is certainly not one of my favorite chores, something about the heat and steam can totally change the outfit’s look. In medical textiles, this process of heat setting is equally important…and not just to look good in the operating room!

At Poly-Med, Inc., we synthesize very unique polymers for extrusion into fibers/yarns and ultimately for knitting into specialized medical textiles. Though the material coming off of the knitting machine looks somewhat finished, the process to manufacture a useful product is often far from done. One such post-processing technique we use is known as heat setting. Though our materials are medical grade and bioresorbable, the core chemistry at work with heat setting our advanced textiles is the same as with ironing common clothing materials.

The long, polymeric chains in both synthetic clothing and our bioresorbable polymers are able to “stick” together to produce fibers by means of intermolecular forces, namely hydrogen bonds. When exposed to moisture, pressure, and/or temperature, these intermolecular bonds can break, shift, and realign to produce unwanted creases. Even without the externally added forces, internal stresses are introduced throughout processing, such as from the twisting of yarn during spinning or the bending of the yarn during knitting to produce the pattern.

To work around this and remove the internal stresses, the fabric can be heated above the Glass Transition Temperature (Tg), where amorphous regions of the polymer can easily slide around. This temperature is below the Melting Temperature (Tm) and thus does not result in a phase change of the fabric, but merely provides enough energy to break down the intermolecular forces in the amorphous region which previously formed into now undesirable positions. As the material cools back down, the intermolecular forces can stabilize into stress-free conditions for whatever configuration the fabric is currently held in. For clothing with a heavy iron on top of it, the result tends to ‘press’ out the wrinkles and flatten the fabric between the flat ironing board and iron.

It is here, in the actual processing methods, that differences arise for our unique materials. In clothing, a particularly pesky wrinkle can be conquered with the addition of steam and a little elbow grease. The addition of water easily penetrates the amorphous regions of the fibers and acts as a plasticizer or lubricant between the polymeric chains, effectively reducing the material’s Tg to allow the amorphous regions more freedom to move. When the material hydrolytically degrades, as with our bioresorbable polymers, the addition of steam isn’t such a great idea. We instead use dry heat, forced air, and even vacuum chambers to apply heat to the fabric and still avoid degradation or strength loss. Heat Setting by these means further allows us to use custom fixtures and presses to hold the fabric in place as it cools, producing flat as well as 3D fabric forms. While this does make the medical textiles look great, the process often improves function as well, improving handle-ability for downstream processing and end-use, allowing the construct to conform to a unique shape, providing dimensional stability, and also increasing temperature resistance.

Though bioresorbable polymers pose a few unique challenges for heat setting, Poly-Med is very experienced in unique solutions for both small and large scale projects. If you are interested in post-processing of medical textiles or you are working on a medical device and are interested in learning more about bioresorbable polymers, Contact us at sales@poly-med.com to learn how we can advance your idea.

Andrew Hargett, M.S.

Design Considerations for Biomedical Textiles: Fiber vs. Yarn

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When terms like “yarn”, “fiber”, and “filament” are used, you might, at first, think that these terms are synonymous. In this blog, we’re going to disentangle the definitions, comb through the types, and dispel the looming cloud of uncertainty, so that you may weave the terms into your sentences with expertise.

When it comes to textiles, there is some additional nuance in the terminology, of which you might not be aware. Fibers, are threadlike strands of material that are significantly longer than they are wide, with an aspect ratio of 100:1. Fibers come in both synthetic and natural forms, ranging from polyesters to silk to cellulose (cotton). Fibers can also be divided up into filament and staple fibers. Filaments are continuous long lengths of fibers (measured in yards or meters) and staple fibers are short lengths (measured in inches). Filament fibers can come in two different forms – monofilament and multifilament – and are produced by extruding polymer through a spinneret to form either a single-strand or multiple-strand filament, respectively.

Yarns are multi-filament meaning they are comprised of a plurality of individual filaments that form a bundle. Yarns are measured in the common textile vernacular of denier, which can be defined as linear density or (mass (g)/9,000 m). Fibers are singular filaments in nature, comprised of a lone solid filament. The choice between using a monofilament or multifilament depends on the target application. For example, a monofilament will have decreased surface area and will be more rigid, compared to a similarly-sized multifilament. Multifilament-based meshes have superior drapability, and a noticeably softer texture, over monofilament-based meshes. Furthermore, your application may need to alter the filament’s denier (linear density) or tenacity (tensile strength), which we can tailor using our variety of polymers or by varying process parameters.

If you are looking to use an extruded bioresorbable fiber or textile in your next medical product, contact us at sales@poly-med.com for more information.

James Turner, Ph.D.

Poly-Med, Inc. Celebrates 25 Years of Innovation in South Carolina

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Poly-Med, Inc., one of the first biotech companies creating bioresorbable polymers for use in medical and pharmaceutical devices is celebrating an important milestone in their history this year; 25 Years of Innovation in South Carolina.

Poly-Med, Inc. was founded by Dr. Shalaby W. Shalaby, considered one of the forefathers of the bioresorbable polymer industry. He was one of the lead inventors for several bioresorbable products that we still use today, notably, the Vicryl®suture.

Dr. Shalaby came to South Carolina in 1990 to teach and conduct research at Clemson University. He launched Poly-Med, Inc. in 1993, as a means to translate his research into medical therapies, as well as to mentor, teach, and sponsor former and current students’ continuing education.

Today, under Dave Shalaby, Dr. Shalaby’s son, Poly-Med, Inc. creates first-in-class transformative bioresorbable medical devices and pharmaceutical products, which have improved millions of patient’s lives. Poly-Med, a once small startup, has been built into a sustainable technology company that attracts and retains the best engineers, scientists, and collaborators from around the world. Dr. Shalaby had a vision when he started Poly-Med, Inc. in South Carolina. He enabled many employees to gain experience, share ideas, in a collaborative effort, and help lay the foundation for the next generation of bioresorbable polymers and medical devices. Under Dave Shalaby’s, leadership, Poly-Med, Inc. has been taken to the next level, and continues to support and improve on the things his father held dear, the application of research,  education, and fostering innovation..

“The work we do at Poly-Med is meaningful in so many ways. As a researcher, we have a chance to work with the most advanced materials and technologies. As a product developer, we work to create first-of-their-kind products to help solve unmet needs. As a collaborator, we get to work with people and companies around the world in a way that we could not have ever imagined. This is how we continue to grow the history of Poly-Med – taking chances, identifying (sometimes hidden) talent, and building new ideas into a meaningful reality.” – Scott Taylor, CTO.

Through continued improvement in personal and professional growth, Poly-Med, Inc. employees are ready and excited to further advance and innovate in the medtech and biotech industries and continue making strides to improve patient quality of life through the devices they manufacture.

Resorbable Ligation Device Elicits Successful Preliminary Results

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Poly-Med, Inc. (PMI) is thrilled to share the success of the LigaTie®, a device designed and developed by Resorbable Devices AB in Uppsala, Sweden that utilizes one of Poly-Med’s Glycoprene® polymers. The LigaTie® device was developed by Dr. Odd Viking Höglund (http://bit.ly/innovator-LigaTie) and addresses challenges associated with ligation during surgical procedures. The device is utilized to restrict blood flow, prevent blood loss, and prevent air leaks, when used on lungs or airways. PMI supports Resorbable Devices AB in the material development of a novel, flexible, fast degrading, absorbable polymer that has been able to meet the demanding specifications of the LigaTie® device. The current product scope initially focuses on veterinary applications, and Resorbable Devices AB has seen great success with clinical results to date.

The LigaTie® has been successful in the following veterinary procedures: in vivo canine neutering, ligation of ovarian pedicles 1, 2 and spermatic cords,3 ex vivo cholecystectomies (removal of gallbladder) to seal the cystic duct,4 ex vivo sealing of lung tissue at lung biopsies,5 in vivo lung lobectomy in dogs with lung cancer,6 and a video-assisted thoracoscopic lung lobectomy (removal of lung lobe).7 The LigaTie® design is based on the concept of a cable tie, and the design allows for ligation of a single artery. The device is a flexible, unidirectional, self-locking, loop device produced from one of PMI’s Glycoprene® absorbable materials (https://poly-med.com/services/implantable-grade-polymers-catalogue/).

Permanent surgical sutures, and other non-absorbable devices (i.e., clips, cable ties, staples), may be used for ligation applications, but threaten to cause negative tissue responses, such as infection, inflammation, or chronic granulomas/scar tissue formation. On the other hand, the LigaTie® exhibits the following benefits due to the novel design and material choice: good tissue grip, easy and minimally invasive placement, which results in a reduction in surgery time (compared to suture ligation), standardized and secure locking mechanism, minimal inflammatory reactions, and acceptable responses for the mechanical performance-to-resorption profile. The preliminary results for the LigaTie® device are extremely promising and truly offer an innovative product for tissue ligation to prevent hemorrhage or leakage of air.

PMI is excited to support companies working to address challenges in the biomedical engineering and biotechnology fields. With PMI’s vertically integrated structure, they are capable of assisting clients take their ideas from exploration and investigation to final manufacturing and market, through in-house material development, analytical testing, product development, and project management. Connect with PMI today to hear more about our material offerings and design, development, and analytical capabilities! If you are interested in hearing more about how Poly- Med can help advance your idea or product, please reach out to us at sales@poly-med.com.

Brittany Banik, Ph.D.
Account Manager
Business Development, Poly-Med, Inc.

1 Höglund, O., et al. (2013). 27(8), pp.961-6. doi: 10.1177/0885328211431018.
2 Da Mota Costa, M., et al. (2016). BMC Res Notes, 9(245), pp. 1-6. doi: 10.1186/s13104-016-2042-2.
3 Höglund, O., et al. (2014). BMC Res Notes, 7(825), pp. 1-7. doi: 10.1186/1756-0500-7-825.
4 Tepper, S., et al. (2017). Can J Vet Res, 81(3), pp. 223-7. PMID: 28725113.
5 Nylund, A. et al. (Accepted). Vet Surg. Evaluation of a resorbable self-locking ligation device for performing peripheral lung biopsies in a caprine cadaveric model.
6 Ishigaki et al. (2017). Presentation at ACVS Surgery Summit. doi 10.1111/vsu.12710.
7 Guedes, R., et al. (2018). Surg Innov., 25(2), pp. 158-164. doi: 10.1177/1553350617751293. Link to video.

The Poly-Med Approach to Medical Device Product Development

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Leading a medical device product development project is always exciting, especially when you are in the resorbable polymer space! One of the most significant milestones is the Design Verification and Validation stage, which requires clinical evaluation.

Answering probing questions is imperative for any medical device product that is being developed, but it becomes even more significant, and challenging, for a novel, marketable, and resorbable device/component. In fact, Poly-Med, being the leader in resorbable materials, understands the importance of this milestone for a clinical trial, and as such, has become the pioneer in developing resorbable components and devices that can perform (at a minimum) like their non-resorbable counterparts, while ensuring the novel device meets unmet market needs.

Poly-Med’s approach to a successful clinical trial, is to set up the design inputs, while planning for verification and validation testing. The biggest challenge for a clinical trial coming up for any device, including resorbables, is having design inputs that will ensure your designed medical device meets the intended uses, as well as the user needs, while still ensuring your processes can meet rigorous design inputs.

Some of the most common items that can be overlooked during the development of a medical device, that are critical for the clinical trials, really fall into the following categories:

– Unclear definition of user needs for the resorbable device

– Not capturing all performance, functional, regulatory, and safety requirements that are required due to the use of a resorbable material

– Ensuring your acceptance criteria (or final device specifications) meet the user need and performance of the device

In addition, without the resources, processes, design inputs, and plan, product development can become an iterative process, which ultimately, will cause scope, time, and going over budget. In summary, the critical task is developing new (scalable, efficient) processes that will allow you to meet your functional design inputs, while still meeting your milestones and budget.

Here is what makes Poly-Med successful during a medical device product development project:

– Resources: Design Verification testing. Without a good plan, things can swirl out of control. Planning for enough resources to keep testing under control, to ensure meeting your other milestones, is critical.

– A Design Verification Plan: Having a strong plan will ensure meeting your milestones and avoiding scope creep. Hence, why it is ideal to start thinking about how you would do Design Verification as you are defining your Design Inputs – this will aid with having a strong, successful Design Verification plan.

– A Good Team: Work ethic is the most important attribute the individuals at Poly-Med have. This allows the teams to create solutions efficiently and fast.

– A Strong Quality Team: Poly-Med’s quality team always ensures the device/component is meeting your Design Controls, which are critical for the success of the project.

If you are interested in learning how Poly-Med can take your idea and translate it into a first-in-class resorbable medical device contact us!

Anna Paola Soliani, Ph.D.
Key Account Manager