3D Printing for Implantable Medical Devices

3D Printing Approaches Overview:

3D printing (additive manufacturing) processes produce three-dimensional parts through addition of material in a layer by layer fashion. Resorbable materials may be 3D printed using a variety of approaches including fused filament fabrication (FFF), selective laser sintering (SLS), and resin-based methods such as stereolithography (SLA) and dynamic light processing (DLP).

FFF produces parts by melting a continuous thermoplastic filament via extrusion through a heated printer head. Although the most widely utilized 3D printing technology, FFF also exhibits the lowest resolution with most printers requiring minimum layers heights ~100 microns and maximum XY resolution ~250 microns. SLS creates parts by sintering powdered materials with a laser to near-melting temperatures which causes the powder particles to fuse together to form a solid structure. SLS exhibits medium printing resolution most printers requiring minimum layer heights ~60 microns and maximum XY resolution ~80 microns. SLA produces parts through a photopolymerization process where a UV laser is focused on a photopolymer vat. SLA exhibits the highest resolution of the described methods with a minimum layer height ~50 microns and maximum XY resolution ~50 microns. Bioresorbable 3D printing materials are available for FFF, SLS, and more recently SLA-based printing methods.

3D Printing Unlocks New Design Architectures for Tissue Scaffolds:

Traditional injection molded parts are limited to solid infill designs due to the requirement resin flowing throughout a mold. In contrast, 3D printing allows for complex infill geometries such as the gyroid and honeycomb patterns to alter both the mechanical properties and cellular infiltration into the device based on its intended use. Additionally, utilization of bioresorbable materials allows for the device to maintain mechanical strength while it is needed, and to degrade into constituents that may be metabolized or excreted once the healing process has sufficiently progressed.

Figure 1: A catalog of infill patterns are accessible via 3D printing that are not accessible via traditional injection molding approaches. These patterns include but are not limited to A) line, B) gyroid, C) octlet, D) concentric, E) tri-hexagon, and F) grid infill designs (Images from Xometry.com).

FFF 3D Printing versus Micro Injection Molding Bioresorbable Devices:

Micro-injection molding is a manufacturing process capable of producing parts between 0.1- 1 gram with tolerances ranging from 10-100 μm. As with traditional injection molding, design changes to the part mold may be prohibitively expensive with each mold costing ~$10,000 for low-volume/simple molds and up to $100,000 to high volume molds. Given the high barrier to entrance into injection molding, PMI’s FFF filament line of materials offers biomedical engineers the ability to iteratively test bioresorbable medical devices designs quickly and cost effectively. Additionally, PMI’s FFF filament materials are offered in standard 1.75 mm formats that are compatible with most open source FFF printers. For volumes applicable to many implantable medical devices, FFF printing is an economical alternative to injection that opens new design features to be imparted better suited for bioabsorbable implants.

Figure 2: Poly-Med offers a catalog of off-the-shelf bioabsorbable filaments for FFF 3D printing to be used in custom development projecs. Available materials include A) Dioxaprene® 100M, B) Strataprene® 5525, C) Lactoprene® 7415, and D) Lactoprene® 8812.

Poly-Med’s now offers Photoset® Resin for Photo-Polymerization 3D Printing Methods:

Poly-Med’s team of material scientists have developed first-in-class bioresorbable fast-degrading resins for photopolymerization 3D printing methods that include SLA, DLP, and two (2) photon polymerization. In contrast to the limited bioresorbable 3D printing resins currently available, Poly-Med’s Photoset® resin product line utilizes monomeric constituents that have used in medical devices for over forty (40) years and are anticipated to be biocompatible with the data collected to date. Additionally, Poly-Med’s material scientists can tune the Photoset® resin mechanical properties and degradation timeline to best meet a device’s requirements. 3D printing with Poly-Med’s Photoset® resin allows for unparalleled resolution when manufacturing bioresorbable medical implants that require small design features.

Figure 3: Example of model part printed with Poly-Med’s Photoset® bioabsorbable resin. The Photoset® resin is available in three (3) formulations with varying degradation profiles and tensile moduli.

Poly-Med’s 3D Printing Services:

In addition to supplying materials, Poly-Med also offers design engineering and 3D printing services for parts made of FFF and SLA materials. Whether a design is not in its final iteration and consultation is needed or if a part design has been finalized and prototypes are needed for testing, Poly-Med’s design engineering is available to provide requested services.

Figure 4: Poly-Med offer fully service 3D printing design, development, & manufacturing services for absorbable medical devices.

Poly-Med is a Vertically Integrated Bioresorbable Medical Device Manufacturing Partner:

Manufacturing bioabsorbable medical devices is hard. Controlling moisture levels and material degradation through the production cycle requires specialized equipment and process controls to ensure quality of finished devices. In contrast to other bioresorbable polymer manufacturers, Poly-Med produces polymer, is able to extrude this material to desired monofilament or multifilament formats, and is able process this material via warp knitting, weft knitting, or braiding processes to produce custom biomedical textiles. Beyond traditional textiles, we can process our bioresorbable polymers into non-woven formats via electrospinning via our state-of-the-art electrospinning facility. In addition to accessing Poly-Med’s more than thirty (30) years of experience manufacturing bioresorbable polymers, partnering with Poly-Med simplifies your bioresorbable medical device manufacturing supply chain. Contact us to today begin developing your custom bioresorbable medical device product line with a trusted partner for manufacturing advanced bioresorbable medical devices or purchase off-the-shelf high-performance bioresorbable polymers!

Figure 5: Poly-Med is a vertically integrated manufacturing partner from polymer synthesis of advanced bioresorbable materials, to polymer processing based on an applications requirements, to a finished medical device or construct. Poly-Med’s vertical integration results in our customers getting their product to market faster, and simplifying our customer’s supply chain upon commercial launch of a product.

Poly-Med, Inc. Welcomes Governor Henry McMaster

GREENVILLE, S.C., October 13th, 2021 — Governor Henry McMaster visited with state leaders and the executive leadership team of Poly-Med, Inc.’s at its newest facility located just outside of Greenville, SC last week.  Governor McMaster’s visit was aimed at taking stock of the ever-growing biomedical industry and Poly-Med’s growing presence in the medical device industry right here in the Upstate.

In 2019, Poly-Med, Inc., the leader in bioresorbable materials and medical device development, opened a state of the art development and production facility doubling their footprint in the Upstate.  The new facility greatly expands PMI’s capabilities to offer medical device development for  medical-grade electrospinning, extrusion, additive manufacturing, and technical textile processes in a certified ISO Class 8 environment. 

Governor McMaster was encouraged by the growth of the company and the technological advancements that Poly-Med has achieved in recent years of utilizing resorbable materials to expand medical device and implant functionality.  The Governor and many others at the state level are encouraging manufacturing investment in the life sciences and biomedical industries within the State. During his visit, the Governor toured Poly-Med’s facility and evaluated its innovative technologies used to produce implants that act as a natural scaffold in the body to replace damaged or diseased tissues.

Poly-Med’s President, David Shalaby, stated “Poly-Med is a solutions’ driven organization that is working on the next class of medical devices.  The expansion of our facilities demonstrates Poly-Med’s dedication to build an infrastructure for custom medical device development within South Carolina. Our focus within the specialty resorbable material field continues our long history of designing and delivering first in class products. We look forward to growing our presence in South Carolina to support our clients in their medical device design and resorbable implant needs that improve the quality of life for patients.” 

The expansion of Poly-Med’s facilities is an investment in the ever-growing life sciences community in the Southeast, particularly in South Carolina. South Carolina is home to a $12+ Billion industry with over 700 dedicated life science firms. To learn more about Poly-Med or the opening of the new facility, please contact Poly-Med.

About Poly-Med, Inc.

For the past 28 years, Poly-Med has developed first in class innovative medical implants that improve the quality of life for patients.  Poly-Med’s mission is to drive innovation in the biomedical industries that positively impact human health. 

Outreach Contact: Joey Thames

864-760-2104 joey.thames@poly-med.com

Analytical Testing for Bioabsorbable Polymer Medical Devices: In-Vitro Degradation Studies

Bioabsorbable polymers were first introduced in the 1960s and have gained traction in the use of medical devices due to their ability to be safely resorbed; thus, leading to a reduction in complications typically observed with the long-term use of foreign material in the human body. These materials are unique in that they can be tailored to a specific application or intended use through various processing techniques to alter their material and physical properties, as well as their degradation profiles. These processing techniques range from different manufacturing processes and sterilization methods to the inclusion of additives during the synthesis of the polymer or during the manufacturing process. Throughout literature, it is noted that these processing techniques can drastically alter the bioresorbable polymers’ properties and degradation profiles; thus, it is imperative that the material and physical properties of the material be captured in a physiologically relevant environment through custom in vitro degradation studies.

At Poly-Med, Inc., we offer a variety of services to characterize the properties and degradation profiles of bioabsorbable medical-grade polymers, components, and devices. These services range from creating custom biomedical solutions to performing analytical evaluations. Poly-Med’s expertise in bioabsorbable polymer analytical evaluations has allowed us to become leaders in performing custom in vitro degradation studies in simulated and controlled environments. Utilizing ASTM standards, primarily ASTM F1635 (Standard Test Method for In Vitro Degradation Testing of Hydrolytically Degradable Polymer Resins and Fabricated Forms for Surgical Implants), the degradation rates and changes in material and physical properties can be characterized to provide an understanding of how the polymer will behave in a physiologically relevant environment. Most importantly, we are able to characterize the molecular weight, strength retention, and mass loss profiles over a designated period of time to construct the degradation profiles.

PMI’s medical-grade bioabsorbable polyester-based polymers typically demonstrate strength loss prior to exhibiting complete mass loss, as depicted in Figure 1. Initially, when these types of implants are placed in an in vitro environment, the implant will interact with the surrounding water molecules leading to water absorption and penetration in the implant itself. While this process is complex, these water molecules will penetrate the implant, which will lead to the polymer chains undergoing hydrolytic degradation cleaving into smaller and smaller chains. Material properties, as well as material processing (e.g., annealing procedures, implant dimensions, etc.), can influence degradation behavior, including monomer content, molecular weight, hydrophilicity, crystallinity, phase microstructure, and thermal properties.

Figure 1: Representative degradation profile observed of bioabsorbable polyester-based polymers.

As PMI’s polyester-based polymers undergo bulk erosion, degradation initially occurs within the amorphous microdomains of the polymer (Figure 2). As the degradation process ensues, the implant will lose its molecular weight, which leads to a loss in the material’s strength. This will ultimately lead to the complete mass loss of the polymer over time, as the implant remains exposed to the in vitro environment.

Figure 2: Representative bulk erosion profile observed of bioabsorbable polyester-based polymers

As each implant displays different strength retention and mass loss profiles, in vitro degradation studies provide the ability to accurately characterize the polymer material’s response in a physiological in situ environment; as well as provide an understanding of the effects of various manufacturing processes on the materials’ strength retention and mass loss profiles.

As degradation profiles for these polymers can range from days to years, it can be necessary to characterize the material’s degradation profile along with material and physical properties at an accelerated rate. This can be accomplished by performing in vitro degradation studies at an increased temperature of 50°C compared to the standard temperature of 37°C. By elevating the study’s temperature, the strength retention and mass loss profiles are able to be evaluated and characterized in a shorter duration than compared to the real-time monitoring performed at 37°C.  When degrading at elevated temperatures, a specific polymer’s thermal properties (i.e., glass transition temperature and melting temperature) should be assessed as these properties can significantly alter degradation behavior. Despite providing a quicker timeframe in capturing the degradation profile, in vitro degradation studies should always be conducted at 37°C to ensure an accurate representation of the real-time response under physiological conditions. As degradable polymers are evaluated for new implantable devices, continuous improvement in the standardization for characterizing degradation behavior is essential. Though ASTM F1635 continues to be the go-to guide for researchers, considerations for accelerated in vitro testing and theoretical modeling may assist in establishing a more robust methodology when evaluating bioabsorbable implants for human use.

Contact us today to set up your custom in vitro degradation study!

Bioabsorbable Polymers: Poly-Med Chairs Workshop on the Use of Absorbable Polymers for Medical Devices

In late January, Poly-Med, Inc.’s Chief Technology Officer, Dr. Scott Taylor, organized and chaired a two-day virtual workshop on the use of absorbable polymers for medical devices sponsored by ASTM Committee F04 on Medical and Surgical Materials and Devices.  The ASTM International defines and sets global standards across industries; these standards are used to improve product quality, enhance health and safety, strengthen market access and trade, and build consumer confidence. Standardization is an important factor in the medical field, and being able to lead this committee gives us the platform to influence and help set the optimal standards. Poly-Med contributes using its experience with the development of medical-grade polymers, scaffolds, and devices for use in medical devices and components.

The workshop had three main areas of discussion: 1) Polymer – Device Characterization 2) Novel Polymers and Processes, and 3) Clinical / Regulatory considerations for absorbable polymers for medical devices. As absorbable polymers are designed to degrade in the body, Polymer – Device Characterization is of paramount importance in understanding the mechanism of degradation and the resulting impact on the device, as well as the impact on the surrounding environment. Industry leaders from Johnson and Johnson led this session with the discussion and presentation of in vitro models to elucidate the role of simulated use and its effect on device performance and functionality during the degradation period. When designing such models, researchers have progressed from conducting simplistic experiments (phosphate-buffered saline, body temperature (37°C), gentle agitation), to physiological relevant models that replicate not only internal conditions but use cases and physiological loading specific to the implantation environment. Speakers in this session also provided insight into human factors and how external factors from the user, could alter the outcome of device characterization. Human factor training in device deployment and tissue placement can vary based on surgical training. As we have learned firsthand at Poly-Med, simulated use models and studies lay the foundation for understanding how a material will behave in the body and provides insight into key stages of device performance and eventual resorption.

The second session, “Novel Polymers and Processes,” focused on the two emerging processing technologies of electrospinning and additive manufacturing. Electrospinning is an established methodology that can create fibrous scaffolds that closely align with native tissue topography and mechanics, as wells as size-scale. Electrospinning is a highly tunable, versatile, and commercially successful technology that is based on consistency and scalability. The use of electrospun materials has been catapulted by the ever-expanding cell therapy markets ($11 billion in global financing in 2020). Moreover, the use of these electrospun implants acts not only as delivery and retention vehicles but also as an immuno-protective membrane. By mimicking size-scale and having a high level of porosity, cellular populations can grow on these materials and allow the release of cellular-based materials and chemicals to stimulate a biological response. Additional research is continuing to understand the specific attributes of fiber quality, size, and consistency, as well as their effects on positive clinical outcomes.

Additive manufacturing, with a focus on digital light processing, is another emerging platform that aims to provide patient-specific implants with geometries and properties for peak performance by overcoming the limitations of current manufacturing processes. With digital light processing, though significant enhancements have been made regarding machine and software solutions, material solutions are quite limited. To date, material solutions are limited based on the desired mechanical properties, as digital light processing is more suited for the printing of precise parts rather than load bearing parts. Furthermore, current photoinitiators are cytotoxic due to the high quantities required for curing of the printed parts, and initial evaluations of biocompatible photoinitiators have suffered from uncontrollable swelling when placed in an in situ environment. Desirable traits of such polymer systems include not only long-term manufacturability, but also the thorough characterization of these systems through in vitro models and the complete understanding of the breakdown of products and eventual clearance from the body. At Poly-Med, we continue to perform research into this area and are dedicated to expanding the development of absorbable polymer systems that can benefit device development and human health.         

The final session of the conference presented cases of clinical translation of absorbable devices as well as the regulatory considerations for future absorbable device development. Case examples of absorbable devices spanned uses from wound care and neurological tissue repair to stenting technologies. In each of the presented clinical cases, the importance of implant design and material selection was heralded as being of top importance for successful patient outcomes. With absorbables designed to degrade, a thorough understanding of the implant performance at the clinical level was instrumental in the surgical training and education required for the adoption of absorbables. The final speaker of this session, from the FDA, presented the regulatory challenges facing absorbables. Challenges with these materials stem from their dynamic nature, unique handling control, and processing parameters required of these materials. One specific area of discussion was the evaluation of polymer molecular weight and the use of inherent viscosity in place of molecular weight characterization by gel permeation chromatography (GPC). GPC analysis includes the characterization of molecular weight (both average and number) along with polydispersity. Such information may prove vital in understanding the degradation mechanisms of absorbable materials, though the final result may be the same – a resorbed medical implant.

In summary of the workshop, Dr. Scott Taylor concluded the following: “across the globe the use of absorbable polymers in medical devices continues to grow at an exponential pace. The industry is seeing a resurgence in not only the need for devices to degrade over time to limit patient complications, but also the emerging fields of regenerative medicine and tissue engineering. This committee will continue to define the standards for such devices to ensure consistent quality and establishment of unifying standards for future absorbable material use in the medical fields.” For more information contact us here.

Dr. Shalaby honored with InnoVision Award – The Dr. Charles Townes Individual Achievement Award 2020

In November 2020, Poly-Med’s founder, Dr. Shalaby W. Shalaby, was awarded the Dr. Charles Townes Individual Lifetime Achievement Award. This awardhonors an individual who has exhibited a sustained commitment to the advancement of technology and the community through his/her technology-oriented and innovative contributions. Such contributions may be business, civic, and/or educational in nature and must benefit the state of South Carolina (SC).

InnoVision describes its awards program as the only one of its kind, calling it “a grassroots, volunteer led non-profit made-up of businesses, organizations, universities, and individuals dedicated to finding innovation and technology in products, services, and education from across the state, and recognizing and honoring peers for achievements in their respective fields.”

At Poly-Med, our roots and humble beginnings have always been a significant part of who we are and who we aspire to be. With the nomination and selection of Dr. Shalaby as the recipient of this award, this award honors Dr. Shalaby as an individual who has exhibited a sustained commitment to the advancement of technology and the community through his/her technology-oriented and innovative contributions. 

In 1990, Dr. Shalaby came to the Upstate of SC to become a bioengineering professor at Clemson University; a post he was offered based on his pioneering work in the field of antibiotic delivery systems, bioadhesives, and bioabsorbable polymers. He was a prolific writer of successful federal grants, which provided research experience and financial support to scores of Clemson University graduate students. In 1993, he founded Poly-Med, Inc. in the Clemson Research Park, where he built two state-of-the-art R&D and manufacturing facilities, which served as a training ground for life science students at Clemson University. 

In the twenty years Dr. Shalaby called the Upstate home, he brought honor and distinction to the Clemson University institution and numerous graduate students, who had the privilege to have him as a mentor. Additionally, South Carolina served as a place where he demonstrated that innovation could flourish. Decades before there was talk of creating a “knowledge economy” in the state, Dr. Shalaby was a living spirit of innovation, entrepreneurship, and job creation in his work at Clemson University and Poly-Med. While he had numerous opportunities to have his company acquired by giants in the life science industry, he chose to remain in the Upstate. He cherished the relationships and close ties with Clemson University and the opportunities of providing young, innovative minds hands-on experience in a real-world lab setting and the ability to create real-world life science breakthroughs.

Dr. Shalaby’s legacy of innovation will continue far into the future due to his impact on the lives he touched. His family and the Poly-Med team continue to mature and commercialize his ideas into the next generation of medical device innovations.  

More about the Innovision Awards

InnoVision Awards, established in 1999, is South Carolina’s premier organization dedicated to the advancement of innovation and technology. InnoVision is the only program of its kind – a volunteer-led non-profit organization comprised of public and private partners from businesses, organizations, universities, along with individuals dedicated to discovering innovation and technology in products, services, and education from across the state of South Carolina.  InnoVision seeks to recognize and honor peers for their achievements in their respective fields and the award is a  mark of distinction for outstanding leadership, innovation, and technological excellence. 

Advanced Absorbable Materials for Combination Medical Devices

Polymeric drug delivery systems have undergone significant development in the last two decades. Polymeric drug delivery has defined as a formulation or a device that enables the introduction of a therapeutic substance into the body.  Biodegradable and resorbable polymers make this possible choice for lot of new drug delivery systems.

Challenges of drug administration:

Administration of a therapeutic requires optimization of dosing regimens to maximize therapeutic benefits while minimizing unwanted side effects to patients. This optimization is governed by four (4) basic pharmacokinetic principles: 1) absorption, 2) distribution, 3) metabolism, and 4) excretion. For any given active pharmaceutical ingredient (API), a number of considerations must be taken into account when designing dosage regimens which include: 1) routes of administrations, 2) site of therapeutic action, 3) the necessity of maintenance doses to ensure long-term therapeutic benefit, and 4) size of the therapeutic window.

Controlled release drug delivery systems:  

Controlled release drug delivery systems have the potential to augment both the bioavailability and distribution profile of a given API. These systems have the ability to deliver APIs at a constant rate over long periods of time, resulting in decreased fluctuations in drug concentrations outside of a given APIs’ therapeutic window. In turn, this can decrease the dosing frequency for a given API and ultimately lead to increased patient compliance. The controlled release of APIs formulated for oral dosing is well-established through the use of complexation resins and coated reservoir systems. In contrast, non-oral controlled release drug delivery systems have historically been more challenging.

Parental drug delivery (e.g., intramuscular, intravenous, and subcutaneous administrations) is required for a number of APIs due to factors that include low bioavailability and a low tolerance for the chemical environments of the stomach and/or GI tract. Recent advances in excipient drug delivery techniques for parental administration have improved the ability to control a given API’s systemic delivery rate.

Figure 1: Theoretical plasma drug concentration versus time curves for traditional oral dosing and controlled drug release systems.

Electrospun materials:

Bioresorbable electrospun materials are an ideal excipient system given their ability to release APIs in a controlled manner over days rather than minutes/hours. These materials are also optimal due to their ability to act as a scaffold for large quantities and a variety of APIs while maintaining their biological activity. Bioresorbable electrospun materials can be degraded via natural metabolic processes and do not require surgical removal post-implantation.

Electrospinning is a process of manufacturing non-woven fibrous materials where a high voltage is applied to a probe connected to a polymer solution (which may contain an API). Once a sufficient amount of charge has accumulated to break the surface tension of the solution, a cone will form that allows for a liquid stream of polymer to be ejected at a continuous rate towards a spool. This material is then collected on the spool and can be used for downstream processing. Fibers produced via electrospinning exhibit diameters on the submicron scale (µm), causing these materials to have high surface area to volume ratios. Electrospun materials have successfully been produced for biomedical purposes ranging from controlled-release orally-dosed APIs, to wound healing applications.

Figure 2: Poly-Med’s advanced absorbable materials can be electrospun into nanofiber sheets (Panels A and B) that may be incorporated with an active pharmaceutical ingredient (API) of interest.

Case study of successful preclinical long-term drug delivery strategy: Cisplatin

Various strategies have been developed for increasing the therapeutic benefits of certain APIs while decreasing their toxicity. Cisplatin is a highly toxic chemotherapeutic agent commonly used to treat a variety of different cancers. Cisplatin induces cell-death by causing non-specific DNA crosslinks to occur in not only cancer cells, but also healthy cells. This, in turn, causes both on-target regression of tumor cells, and several unwanted side effects that include nausea, kidney damage, nerve damage, heart failure, and hearing loss. IV administration of cisplatin results in high initial plasma drug levels which rapidly decrease with a half-life of roughly thirty (30) minutes. These plasma concentrations are contrasted with low tumor penetration, which limits the potential overall benefit of the therapeutic intervention. An ideal administration regimen of cisplatin would increase the tumor concentration of the API to maximize chemotherapeutic effects while simultaneously decreasing the plasma drug concentration to decrease unwanted side effects.

Preclinical studies by Shikanov, et al., 2011 illustrate this point. Using a bioresorbable polymer to control the delivery of cisplatin, the study was able to significantly improve therapeutic outcomes in a mouse model of bladder cancer while decreasing systemic exposure to the drug.

Remarkably, administration of cisplatin with the bioresorbable polymer directly into the tumor resulted in a five (5)-fold increase in the maximum tolerated dose (MTD) compared to systemic administration. In addition to increased tolerance of cisplatin, significant improvements in therapeutic outcomes and API distribution were observed. Local tumor injection of the bioresorbable excipient system resulted in 80% of subjects remaining disease-free for forty (40) days (i.e., the remainder of the study). This is in stark contrast to standard systemic administration of cisplatin which resulted in exponential tumor mass growth after seven (7) days. In line with the observed therapeutic benefits, local tumor administration of the bioresorbable excipient system resulted in drug levels at the site of administration over five-hundred (500) times higher than levels observed with systemic administration. Additionally, reverse trends were observed in systemic exposure where local tumor administration of the bioresorbable excipient system resulted in an eighty (80)-fold decrease in plasma drug levels compared to systemic administration. Together, this highlights the potential for polymer/API excipient systems to maximize exposure to the desired site of action, while simultaneously limiting systemic exposure to APIs and potentially decreasing side effects.

Absorbable polymers offered by Poly-Med, Inc. as excipients for drug delivery:

Poly-Med, Inc. (PMI), the leader in bioresorbable materials and medical device development, is vertically integrated with design, development, and manufacturing capabilities. PMI has a growing opportunity for providing materials for drug delivery via PMI’s unique Viscoprene® technology.  Electrospun materials are generated using a combination of the Viscoprene® polymer that forms a base depot for drug delivery with additional polymeric diluents/APIs. Once combined, this drug delivery system can be injected through a standard Luer-Lok needle and syringe to be administered into the desired anatomical location. Additionally, PMI offers a catalog of Viscoprene® polymers, which allows for tailoring of the release properties of the API to meet the necessary clinical treatment schedule.

Figure 3: Poly-Med’s Viscoprene® polymer excipient forms a depot in aqueous solution and is ideal for long-term delivery of APIs.

Poly-Med is a Vertically Integrated Bioresorbable Medical Device Manufacturing Partner:

Manufacturing bioabsorbable medical devices is hard. Controlling moisture levels and material degradation through the production cycle requires specialized equipment and process controls to ensure quality of finished devices. In contrast to other bioresorbable polymer manufacturers, Poly-Med produces polymer, is able to extrude this material to desired monofilament or multifilament formats, and is able process this material via warp knitting, weft knitting, or braiding processes to produce custom biomedical textiles. Beyond traditional textiles, we can process our bioresorbable polymers into non-woven formats via electrospinning via our state-of-the-art electrospinning facility. In addition to accessing Poly-Med’s more than thirty (30) years of experience manufacturing bioresorbable polymers, partnering with Poly-Med simplifies your bioresorbable medical device manufacturing supply chain. Contact us to today begin developing your custom bioresorbable medical device product line with a trusted partner for manufacturing advanced bioresorbable medical devices or purchase off-the-shelf high-performance bioresorbable polymers.

Figure 4: Poly-Med is a vertically integrated manufacturing partner from polymer synthesis of advanced bioresorbable materials, to polymer processing based on an applications requirements, to a finished medical device or construct. Poly-Med’s vertical integration results in our customers getting their product to market faster, and simplifying our customer’s supply chain upon commercial launch of a product.

Bioresorbable Polymer Composites as Implantable Medical Devices

As the emergence of tissue engineering and regenerative medicine fields continue to take off, Poly-Med, Inc. has long been a partner and proponent in innovative scaffold design.  With the ability to be a one-stop-shop for implantable scaffold and device development from polymer to product, Poly-Med has been able to build upon its research expertise and was recently awarded a patent by the US Patent office for its scaffold technology.  United States Patent # 10,004,833 titled “Absorbable Permeability-Modulated Barrier Composites and Applications Thereof” highlights the manufacture of a multilayered constructs comprised of varying materials for use as a scaffold in a variety of indications.  

The invention deals with an absorbable permeability modulated barrier composite that is fabricated from a multi-layered structure forming a composite to better mimic natural tissue properties.  One of the major benefits with composites is that multiple structures of different physico-chemical materials can be adjoined and form a singular construct with unique properties.  Within the invention, the composite material is constructed from a base layer that is a flexible film combined with additional reinforcement from a textile structure, and microfibrous layer using Poly-Med’s proprietary electrospinning processes.  The physico-chemically distinct layers provide unique properties whereby varying morphologies and chemistries can elicit different biological responses when implanted in the body.  With the microfibrous coating, the fibers are able to better replicate the topography of the native extacellular tissue structure.  The microfibrous layer can vary in both fiber properties (size) and thickness to provide a soft layer that can be readily infiltrated with a patient’s native cells.  Applications of this technology can range from general surgery use, neurological use, bladder replacement, musculoskeletal tissues, among others.     

As with all of Poly-Med’s technologies, the ability to tailor polymer chemistry and material selection is a key aspect of designing the right scaffold.  Poly-Med polymers are medical grade and can be uniquely tailored based on their exact composition, segmentation, and molecular properties.   With this technology (and others) varying medical-grade polymers from Glycoprene®, Lactoprene®, and Dioxaprene® offer another lever to pull in the design of scaffolds. To learn more about this exciting technology or other technologies available at Poly-Med, contact us at sales@poly-med.com.

Bioresorbable Polymer Films as Degradable Barriers

At Poly-Med (PMI), we pride ourselves in being a “one-stop shop”, providing medical grade materials and processing services at our facilities. PMI is a trusted leader in the production of bioresorbable polymers suitable for our client’s needs. We have a variety of polymers that covers a wide range of physical and mechanical properties. Additionally, PMI is an expert on the processing of bioresorbable polymers via extrusion, technical textiles, electrospinning, as well as additive manufacturing processes.  

One of the key components Poly-Med specializes in is film production by either solvent processing or melt-extrusion.  Films have been extensively used as implantable medical devices as barrier applications in general surgery, wound care, and dental products.  Solvent processing of films is used for highly specialized products where heat sensitive materials can also be incorporated.  Solvent processing is able to incorporate multiple materials, layers within the final film construct, and care is often used in the full characterization of solvent processed films to ensure all residuals are removed to an acceptable level.  

Despite the advantages of solvent processing, melt-extrusion is a more industry standard for creation of film substrates.  Melt-extrusion involves the process of melting and metering polymer through a die to achieve the desired thickness and width dimensions upon quenching. Based on the material properties, downstream equipment such as roller systems are put in place to process the film appropriately.  Key components of the film extrusion lines are polymer feeders, extruder with a proper screw design screw, filtration system, die, quenching equipment, roller assembly, winder, and measurement equipment.

Film extrusion field is divided into two (2) categories: 1) cast, or flat film extrusion and 2) blown film. For the flat film extrusion, a die is used to direct the flow of melted polymer into a dimension controlled film. Several aspects need to be considered when setting the die gap distance such as polymer swelling, collector, and desired dimensions. It is critical to ensure constant and uniform flow of the polymer across the area of the die. The downstream equipment such as roller systems are used to ensure that the final product meets the client’s specifications. Typical film specification includes dimensions, texture, uniformity, and material molecular weight among others. Specifications must be clearly defined based on the final product functionality. 

At PMI, our engineers work diligently to identify the balance between process and final product characteristics.  Based on the polymer’s properties and product specifications, process parameters are developed to ensure the constant flow of the polymer and proper quenching of the final product. This ensures that the material is stable to either be used as the final component or be processed based on the client’s needs.

PMI specializes in contract manufacturing of components using medical grade polymers. With PMI’s vertically integrated structure, our diverse team of experts supports our clients from the initial phases of device conception and prototype development to manufacturing by providing in-house device development, project management, quality assurance, and analytical testing. Following process validations and regulatory clearance, PMI provides manufacturing services, inspection plans with validated test methods, packaging, and schedule deliveries to our clients worldwide. Our PMI team is committed to providing high quality products at a reasonable cost through constant process improvement to production lines. Connect with PMI today to hear more about our product offerings and design, development, and analytical capabilities! If you are interested in hearing more about how Poly- Med can help advance your idea and medical product conception, please contact us here.

Medical-grade electrospinning for tissue engineering and regenerative medicine: a new tool for biomedical textiles

As the global medical device field continues to expand (currently >$330 Billion), a paradigm shift has focused on the creation of resorbable medical devices.  This movement has been driven by the desire of final device manufacturers to replace current non-degradable implants along with the application and creation of resorbable devices (and scaffolds) in the emerging fields of tissue engineering and regenerative medicine.  The fields of tissue engineering and regenerative medicine seek to replace and repair damaged tissues with a temporary (resorbable) scaffold that can allow new tissues to form within the body.  Resorbable polymers that can degrade into natural metabolites (e.g. H2O and CO2) can create this temporary scaffold and support structure through a variety of manufacturing processes.  

Beyond traditional manufacturing methodologies, processes that can produce implants that closely mimic the native properties within our tissues (skin, ligament, bone, cartilage, blood vessels) are on the forefront of improving medical device design.  By having medical devices that can replicate the appropriate architecture of the tissues they are meant to replace, innate healing mechanisms including cellular growth, development, and maturation can occur accelerating the healing process and forming new tissues. Of the manufacturing tools available at Poly-Med, Inc., electrospinning enables the use of a wide variety of resorbable materials allowing for different physical, mechanical, and degradation rates to be achieved through a unique fiber formation process.  

Electrospinning is an electrostatic fiber fabrication method, which uses electric force to draw a charged extension of a polymer solution into fiber diameters on a submicron scale. Using strong electric fields to generate submicron fibrous scaffolds, electrospinning has the capability to be used in a variety of indications ranging from fibrous coatings on implants to entire stand-alone devices or constructs.  

Fibrous materials created by electrospinning are comprised of a plurality of fibers resulting from an infinite number of fiber-fiber contacts and layers upon layers of fibers.  Engineering criteria for electrospun products revolve around fiber size, pore size, fiber orientation, intermixed fiber populations, and layered constructs comprised of different types of fibers and materials.  Based on these criteria, standard surgical mesh specifications including basis weight (areal density), thickness, and mechanical properties can easily be tuned and measured.  

Beyond control of the physical dimensions of an electrospun mesh, electrospun devices also allow for the easy incorporation of medical grade additives or active pharmaceutical ingredients (APIs).  As electrospinning does not typically require elevated temperatures, sensitive materials like APIs can easily be incorporated into the bulk fiber during the electrospinning process.  Besides inclusion of APIs inside fibers, physical adsorption is also possible as constructs often exhibit very high surface area to volume ratios.  Electrospun products can have varied porosities greater than seventy (70) percent!  

At Poly-Med, we specialize in novel processing of biomaterials and know first-hand what it takes to manufacture electrospun medical products on a commercial scale.  Beyond standard engineering practices of equipment qualification and process validation, we have been able to establish our own standards for tight manufacturing and process controls to allow highly capable medical grade electrospinning processes for desired outcomes and high quality products.

To summarize, medical-grade electrospinning provides an innovative tool for medical device development and has shown great promise in enabling new and exciting products.  With the ability to provide industrial scale electrospinning services, PMI can help you develop your next medical device! Contact us to learn how our electrospinning expertise can help you advance your next bioresorable medical device!

Biomedical Textile Spotlight: Braiding Bioresorbables

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 bioresorbable 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!