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  1. Statement of Purpose: Orthopedic implants are important therapeutic devices for the management of a wide range of orthopedic conditions. However, bacterial infections of orthopedic implants remain a major problem, and not an uncommon one, leading to an increased rate of osteomyelitis, sepsis, implant failure and dysfunction, etc. Treating these infections is more challenging as the causative organism protects itself by the production of a biofilm over the implant’s surface (1). Infections start by the adhesion and colonization of pathogenic bacteria such as Staphylococcus aureus (SA), Staphylococcus epidermidis (SE), Escherichia coli (E. coli), Methicillin-Resistant Staphylococcus aureus (MRSA), and Multi-Drug Resistant Escherichia coli (MDR E. coli) on the implant’s surfaces. Specifically, Staphylococcus comprises up to two-thirds of all pathogens involved in orthopedic implant infections (2). However, bacterial surface adhesion is a complex process influenced by several factors such as chemical composition, hydrophobicity, magnetization, surface charge, and surface roughness of the implant (3). Considering the intimate association between bacteria and the implant surface, we measured the effect of stainless-steel surface properties on bacterial surface attachment and subsequent formation of biofilms controlling above mentioned factors. Method: The prominent bacteria responsible for orthopedic implant infections (SA, SE, E. coli, MRSA, and MDR E. coli) weremore »used in this study. We were able to control the grain size of medical grade 304 and 316L stainless steel without altering their chemical composition (grain size range= 20μm-200nm) (4). Grain size control affected the nano-topography of the material surfaces which was measured by an Atomic Force Microscope (AFM). Grain sizes, such as 0.2, 0.5, 1, 2, 3, 9, and 10 μm, were used both polished and non-polished. All the stainless-steel samples were cleaned by treating with acetone and ethanol under sonication. Triplicates of all polished and non-polished samples with different grain sizes were subjected to magnetization of DM, 0.1T, 0.5T, and 1T, before seeding them with the bacteria. Controls were used in the form of untreated samples. Bacterial were grown in Tryptic Soy Broth (TSB). An actively growing bacterial suspension was seeded onto the stainless-steel discs into 24-well micro-titer plates and kept for incubation. After 24 hours of incubation, the stainless-steel discs were washed with Phosphate Buffer Saline (PBS) to remove the plankton bacteria and allow the sessile bacteria in the biofilm to remain. The degree of development of the bacterial biofilms on the stainless-steel discs were measured using spectrophotometric analysis. For this, the bacterial biofilm was removed from the stainless steel by sonication. The formation of biofilms was also determined by performing a biofilm staining method using Safranin. Results: AFM results revealed a slight decrease in roughness by decreasing the grain size of the material. Moreover, the samples were segregated into two categories of polished and non-polished samples, in which polishing decreased roughness significantly. After careful analysis we found out that polished surfaces showed a higher degree for biofilm formation in comparison to the non-polished ones. We also observed that bacteria showed a higher rate for biofilm formation for the demagnetized samples, whereas 0.5T magnetization showed the least amount of biofilm formation. After 0.5T, there was no significant change in the rate of biofilm formation on the stainless-steel samples. Altogether, stainless steel samples containing 0.5 μm and less grainsize, and magnetized with 0.5 tesla and stronger magnets demonstrated the least degree of biofilm formation. Conclusion: In summary, the results demonstrate that controlling the grain size of medical grade stainless steel can control and mitigate bacterial responses on, and thus possibly infections of, orthopedic implants or other implantable devices. The research was funded by Komatsuseiki Kosakusho Co., Ltd (KSJ: Japan)« less
  2. INTRODUCTION: Orthopedic implants are important therapeutic devices for the management of a wide range of orthopedic conditions. However, bacterial infections of orthopedic implants remain a major problem, and not an uncommon one, leading to an increased rate of osteomyelitis, sepsis, implant failure and dysfunction, etc. Treating these infections is more challenging as the causative organism protects itself by the production of a biofilm over the implant’s surface (1). Infections start by the adhesion and colonization of pathogenic bacteria such as Staphylococcus aureus (SA), Staphylococcus epidermidis (SE), Escherichia coli (E. coli), Methicillin-Resistant Staphylococcus aureus (MRSA), and Multi-Drug Resistant Escherichia coli (MDR E. coli) on the implant’s surfaces. Specifically, Staphylococcus comprises up to two-thirds of all pathogens involved in orthopedic implant infections (2). However, bacterial surface adhesion is a complex process influenced by several factors such as chemical composition, hydrophobicity, magnetization, surface charge, and surface roughness of the implant (3). Considering the intimate association between bacteria and the implant surface, we measured the effect of stainless-steel surface properties on bacterial surface attachment and subsequent formation of biofilms controlling above mentioned factors. METHODS: The prominent bacteria responsible for orthopedic implant infections (SA, SE, E. coli, MRSA, and MDR E. coli) were used inmore »this study. We were able to control the grain size of medical grade 304 and 316L stainless steel without altering their chemical composition (grain size range= 20μm-200nm) (4). Grain size control affected the nano-topography of the material surfaces which was measured by an Atomic Force Microscope (AFM). Grain sizes, such as 0.2, 0.5, 1, 2, 3, 9, and 10 μm, were used both polished and non-polished. All the stainless-steel samples were cleaned by treating with acetone and ethanol under sonication. Triplicates of all polished and non-polished samples with different grain sizes were subjected to magnetization of DM, 0.1T, 0.5T, and 1T, before seeding them with the bacteria. Controls were used in the form of untreated samples. Bacterial were grown in Tryptic Soy Broth (TSB). An actively growing bacterial suspension was seeded onto the stainless-steel discs into 24-well micro-titer plates and kept for incubation. After 24 hours of incubation, the stainless-steel discs were washed with Phosphate Buffer Saline (PBS) to remove the plankton bacteria and allow the sessile bacteria in the biofilm to remain. The degree of development of the bacterial biofilms on the stainless-steel discs were measured using spectrophotometric analysis. For this, the bacterial biofilm was removed from the stainless steel by sonication. The formation of biofilms was also determined by performing a biofilm staining method using Safranin. RESULTS SECTION: AFM results revealed a slight decrease in roughness by decreasing the grain size of the material. Moreover, the samples were segregated into two categories of polished and non-polished samples, in which polishing decreased roughness significantly. After careful analysis we found out that polished surfaces showed a higher degree for biofilm formation in comparison to the non-polished ones. We also observed that bacteria showed a higher rate for biofilm formation for the demagnetized samples, whereas 0.5T magnetization showed the least amount of biofilm formation. After 0.5T, there was no significant change in the rate of biofilm formation on the stainless-steel samples. Altogether, stainless steel samples containing 0.5 μm and less grainsize, and magnetized with 0.5 tesla and stronger magnets demonstrated the least degree of biofilm formation. DISCUSSION: In summary, the results demonstrate that controlling the grain size of medical grade stainless steel can control and mitigate bacterial responses on, and thus possibly infections of, orthopedic implants or other implantable devices. The research was funded by Komatsuseiki Kosakusho Co., Ltd (KSJ: Japan) SIGNIFICANCE/CLINICAL RELEVANCE: Orthopedic implants that more than 70% of them are made of metals (i.e., stainless steel, titanium, and cobalt-chromium alloys) are failing through loosening and breakage due to their limited mechanical properties. On the other hand, the risk of infection for these implants and its financial burden on our society is undeniable. We have seen that our uniformly nanograined stainless steel shows improved mechanical properties (i.e., higher stiffness, hardness, fatigue) as compared to conventional stainless steel along with the reduction of biofilm formation on its surface. These promising results made us to peruse the development of nanograined titanium and cobalt-chromium alloys for resolving the complications of orthopedic implants.« less
  3. Musculoskeletal conditions such as low back pain, arthritis and other diseases of the joints affect millions of people around the world and are one the leading causes of disability (1). These diseases often require surgery, including total joint replacement in cases of deterioration of the natural joint (2). Serious concern regarding such procedure is the bacteria adhesion and proliferate on the surfaces of these orthopedic implants. Moreover, bacteria have shown the ability to generate resistance against drugs that once could kill them, hence, being more difficult or even impossible to eliminate them. These pathogens are the principal causative agents of two major types of infection in bone: septic arthritis and osteomyelitis, which involve the inflammatory destruction of joint and bone (3). Therefore, there is an unmet need to generate materials capable of showing reduced bacterial adhesion as well as bactericidal effect in order to avoid further health complications. nanoSUS Bio-Tech was founded based on a collaboration between Komatsuseiki Kosakusho Co., Ltd (KSJ:Japan) and Northeastern University (NEU) in 2019. KSJ has been developing ultra-fine-grained stainless steel since 2002 (4, 5). Using this technology, we are able to control the grain size without any changes in the chemical composition of commercially availablemore »FDA approved stainless steel. On the other hand, Thomas J. Webster’s lab has achieved the ability to decrease bacteria adhesion and growth with and without the use of antibiotics, for nanostructured surfaces. As an outcome of this collaboration, we were able to manufacture high strength ultra-fine-grained stainless steel with antimicrobial surface. The global orthopedic implants market was estimated at $45.90 billion in 2017 and is expected to reach at $66.63 billion by 2025, registering a CAGR of 4.7% from 2018 to 2025 (6), due to the growing demand by increasing geriatric population, rising incidence of spine illness and technological advancements in this field. Based on geography, North America accounted for nearly half of the total market revenue in 2017 and is anticipated to retain its top status till 2025. At the same time, the Asia-Pacific region would cite the fastest CAGR of 6.4% throughout the study period. Based on current market trends, companies such as Zimmer, Stryker, S&N, Depuy, J&J, and Medtronic are our target customers. Currently, we are expanding our network in the US by becoming member of Center for Disruptive Musculoskeletal Innovations (CDMI). Moreover, this project is funded through CDMI NSF program that will aid to expand the collaboration between KSJ and NEU. The company will be established by financing from KSJ, in Boston, MA. It will manage the collaborations between academia, marketing consultants and lawyers in the US, and directors and researchers in Japan and the US. We are expecting to start our sales from the beginning of 2021.« less
  4. Vertebral augmentation, which includes vertebroplasty and kyphoplasty, is a minimally invasive procedure to relieve the back pain caused by vertebral compression fracture (VCF) and osteoporosis-related fractures. Vertebroplasty involves the introduction of a percutaneous needle into the vertebral body followed by an image-guided injection of cement directly into the vertebra. The market size for Vertebroplasty is expected to increase from $910 million in 2019, to $1500 million in 2024 with a CAGR of 8.4%, due to the growing demand by increasing geriatric population, rising incidence of spine illness and technological advancements in this field [1]. NanoSUS Bio-Tech (USA) was found based on a collaboration between Komatsuseiki Kosakusho Co., Ltd (Japan) and Northeastern University (NEU) in 2019 [2]. This company manufactures high strength ultra-fine-grained stainless steel with antimicrobial surface. However, nanoSUS has been developing ultra-fine-grained stainless steel since 2002 [3, 4]. Using this technology, we are able to control grain size without any change in chemical composition of commercially available FDA approved stainless steel. We are able to form this stainless steel into a vertebroplasty needle using our precision machining techniques at Komatsuseiki Kosakusho Co., Ltd. We believe this product will reduce the healthcare expenses for patients suffering from VCF due tomore »its cost-effective manufacturing process and antimicrobial surface, which reduces iatrogenic infections and shortens hospitalization time. We are going to submit a funding proposal to Center for Disruptive Musculoskeletal Innovation (CDMI) that will aid to expand the collaboration between Komatsuseiki Kosakusho Co., Ltd and NEU. The company will be established by financing from Komatsuseiki Kosakusho Co., Ltd (Japan), in Boston, MA. It will manage the collaborations between academia, marketing consultants and lawyers in US, and directors and researchers in Japan.« less