{"id":566704,"date":"2025-11-14T17:08:45","date_gmt":"2025-11-14T20:08:45","guid":{"rendered":"https:\/\/revistapesquisa.fapesp.br\/?p=566704"},"modified":"2025-11-14T17:08:45","modified_gmt":"2025-11-14T20:08:45","slug":"scientists-develop-innovative-models-of-prosthetics-and-exoskeletons","status":"publish","type":"post","link":"https:\/\/revistapesquisa.fapesp.br\/en\/scientists-develop-innovative-models-of-prosthetics-and-exoskeletons\/","title":{"rendered":"Scientists develop innovative models of prosthetics and exoskeletons"},"content":{"rendered":"
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L\u00e9o Ramos Chaves\u2009\/\u2009Revista Pesquisa FAPESP<\/span>A below-the-knee prosthesis made from bamboo fibers and castor bean resinL\u00e9o Ramos Chaves\u2009\/\u2009Revista Pesquisa FAPESP<\/span><\/p><\/div>\n

A cost-effective prosthetic leg made from bamboo fibers and castor oil resin is close to becoming a market-ready product. The device\u2014designed for below-the-knee amputees\u2014should cost significantly less than conventional models made from imported carbon fiber and epoxy resin, such as those currently provided by Brazil\u2019s National Healthcare System (SUS). Developed at S\u00e3o Paulo State University (UNESP), the prosthetic has been patented through the university\u2019s innovation agency (AUIN), and negotiations with a prospective manufacturer are well advanced.<\/p>\n

\u201cWe believe we can sell the bamboo version for under R$2,000, depending on production scale and capacity,\u201d says Jo\u00e3o Victor Gomes dos Santos, the product designer heading the project. \u201cThat\u2019s about a third the cost of a typical carbon fiber prosthesis purchased by the SUS.\u201d Santos, who holds undergraduate and graduate degrees from UNESP\u2019s School of Architecture, Arts, Communication, and Design (FAAC) in Bauru, says bamboo\u2019s mechanical strength is comparable to that of carbon fiber, but with the added benefits of being inexpensive and abundant in Brazil.<\/p>\n

A locally made, affordable prosthesis could help shorten the long wait many SUS patients face, Santos believes. \u201cToday, someone who loses a limb might wait a year or longer for a prosthetic,\u201d he says. In 2022 alone, Brazil\u2019s public health system performed 31,190 lower-limb amputations\u2014about 85 every day, according to the Brazilian Society of Angiology and Vascular Surgery.<\/p>\n

To make the bamboo-reinforced composite, fibers are extracted from the plant\u2019s outer layer\u2014close to the rind\u2014and bonded with castor-based resin, Santos explains. \u201cBesides being eco-friendly, recyclable, and cheaper than synthetic fibers, natural-fiber-reinforced polymer composites may be better suited to certain applications,\u201d Santos and colleagues wrote in the book Design, artefato e sistema sustent\u00e1vel<\/em> (Sustainable design, devices and systems; Blucher, 2018). These composites are highly versatile: they can be engineered for particular applications and molded into complex shapes that are hard to produce using conventional materials.<\/p>\n

In another paper presented at the 6th<\/sup> International Conference on Integrity-Reliability-Failure in Portugal in 2018, the team used computer modeling to show that the bamboo prosthesis could safely support users weighing up to 100 kilograms.<\/p>\n

Assistive technologies
\n<\/strong>Santos\u2019s bamboo prosthesis project is among those selected for funding by a new Multidisciplinary Center for Development of Assistive Technology (CMDTA)\u2014one of two Science for Development Centers (CCDs) launched by FAPESP in 2024 to develop innovative technology for people with physical disabilities. The second CCD, the Center for Assistive Technologies for Daily Living (CTecvida), is based at the University of S\u00e3o Paulo (USP).<\/p>\n

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L\u00e9o Ramos Chaves\u2009\/\u2009Revista Pesquisa FAPESP<\/span>A researcher working on a below-the-knee prosthesis developed at UNESPL\u00e9o Ramos Chaves\u2009\/\u2009Revista Pesquisa FAPESP<\/span><\/p><\/div>\n

CMDTA, hosted at UNESP\u2019s Bauru campus, brings together 42 researchers from 17 laboratories across UNESP, USP, the Federal University of S\u00e3o Carlos (UFSCar), and the Federal University of ABC (UFABC). The center also collaborates with local institutions such as Sorri-Bauru, a specialized rehabilitation center; the Association of Parents and Friends of Exceptional Children (APAE); and Hospital Amaral Carvalho, with locations in Bauru and Ja\u00fa (SP).<\/p>\n

\u201cResearchers often work in silos, each focused on their own project,\u201d says physicist Carlos Roberto Grandini of UNESP\u2019s Bauru School of Sciences, who heads CMDTA. \u201cThrough this center, we\u2019re collaborating across disciplines to drive innovation.\u201d<\/p>\n

The bamboo prosthesis project is an example of the kind of collaboration Grandini envisions. Developed in UNESP\u2019s Ergonomics and Interfaces Laboratory, the project will use CMDTA funding to produce prototypes, which will be tested with patients at Sorri-Bauru.<\/p>\n

Several CMDTA-funded projects are currently underway across affiliated labs. One is further developing a transradial prosthesis\u2014for below-the-elbow amputees\u2014created as part of product designer Bruno Borges Silva\u2019s master\u2019s research. Developed within a co-design process where end-users helped create the final product, the prosthesis was built using a rapid prototyping technique combining digital modeling with 3D printing. The device features a myoelectric system in which sensors detect electrical signals from the user\u2019s muscles, capturing their intent to move. These signals are transmitted via Bluetooth, enabling the prosthesis to carry out tasks like gripping a cup or opening a package.<\/p>\n

\u201cThe sensors pick up electrical signals from muscle activity just above the residual limb\u2014on the user\u2019s upper arm, in this case,\u201d explains Lu\u00eds Carlos Paschoarelli, a professor of design at FAAC-UNESP. \u201cTheoretically, we could read signals straight from the brain,\u201d he adds, \u201cbut that would take significantly more research and investment.\u201d The sensors and Bluetooth system are embedded as an assembly within the prosthesis, Paschoarelli explains.<\/p>\n

Co-design, Paschoarelli adds, is an innovative strategy for developing assistive technologies and helps improve user acceptance of prosthetic devices. In a 2020 paper in the journal Educa\u00e7\u00e3o Gr\u00e1fica<\/em>, he explored how the visual design of assistive devices can affect the self-esteem of people with disabilities. \u201cA customized prosthetic not only improves function\u2014it also meets the user\u2019s aesthetic expectations, which helps reduce device rejection or abandonment,\u201d he notes.<\/p>\n

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Bruno Borges da Silva\u2009\/\u2009Unesp<\/span>A prototype transradial prosthesis designed for individuals with below-the-elbow arm amputationsBruno Borges da Silva\u2009\/\u2009Unesp<\/span><\/p><\/div>\n

He believes cross-disciplinary collaboration will help advance his project\u2014especially when it comes to identifying better materials for prosthetics and other assistive devices. The team\u2019s first prototype was made with polylactic acid (PLA), a biodegradable thermoplastic made from natural materials. \u201cPLA prints beautifully with 3D printers,\u201d he says, \u201cbut turned out to be too heavy for everyday use.\u201d<\/p>\n

Mechanical knees and new challenges
\n<\/strong>Another CMDTA-funded project is a monocentric mechanical knee\u2014one with a single pivot point\u2014that offers functionality not available in prosthetics currently provided by the SUS. One innovative feature is a mechanism that allows users to bend the knee while walking\u2014a feature absent in traditional models, which keep the joint locked straight during walking.<\/p>\n

The prototype includes a user-operated lock, letting users choose between a fully extended or flexed knee. \u201cThis is a feature typically only available in high-end prosthetic knees made for athletes,\u201d says physical therapist Guilherme Eleut\u00e9rio Alcalde, one of the project\u2019s co-creators.<\/p>\n

The device also features a spring-based shock absorber, which softens impacts during walking and helps reduce stump pain. \u201cCombined, these systems deliver more comfort, a smoother gait, and greater walking speed,\u201d Alcalde explains.<\/p>\n

In a 2024 master\u2019s thesis, Marcelo Alves de Macedo, one of the project\u2019s co-creators, compared seniors using traditional prosthetics to those fitted with the new UNESP-designed model over a six-month trial. The results were promising: users of the new prototype expended less energy during walking, increasing overall locomotion efficiency. Gait symmetry also improved, which is crucial for lowering fall and injury risks. Participants using the new model also reported less effort and pain when performing everyday tasks.<\/p>\n

Carlos Roberto Grandini, who is leading the project, says one strategy for improving quality while keeping costs comparable to conventional models is selecting more cost-effective materials. The standard-issue mechanical knees provided by the SUS are made entirely from stainless steel. The UNESP prototype combines stainless steel with polypropylene, a cheaper alternative. A next-generation version made from a titanium alloy is also in development. The exact composition of the alloy is being kept confidential until a patent application is filed. \u201cWe expect our prosthesis to offer outstanding cost-benefit,\u201d says CMDTA director Carlos Roberto Grandini.<\/p>\n

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L\u00e9o Ramos Chaves\u2009\/\u2009Revista Pesquisa FAPESP<\/span>Students at UNESP\u2019s Elasticity and Biomaterials Lab performing mechanical tests on a biomedical alloy used in a monocentric prosthetic kneeL\u00e9o Ramos Chaves\u2009\/\u2009Revista Pesquisa FAPESP<\/span><\/p><\/div>\n

The biggest challenge in designing a knee-flexing prosthesis, notes physical therapist Rafael Oliveira, who built the prototype, is replicating the size of a natural knee joint while integrating all the necessary technology to ensure a safe, balanced gait. \u201cGait control depends mainly on the shock absorption and resistance system to allow proper flexion and extension of the knee,\u201d Oliveira explains. \u201cBut every user has different needs, which makes designing a one-size-fits-all mechanical knee particularly challenging.\u201d<\/p>\n

As with other research fields, a major challenge for Brazil\u2019s assistive tech developers is going from prototype to mass production. One issue is the limited capabilities of the few prosthetics manufacturers in Brazil. \u201cThe sector is dominated by micro and small manufacturers,\u201d says Amanda Amorim Rodrigues, an economist with the Health Technology Innovation Lab at UNIFESP\u2019s S\u00e3o Paulo School of Medicine.<\/p>\n

Rodrigues coauthored a 2024 study in Jornal Brasileiro de Economia da Sa\u00fade<\/em> exploring the market potential for assistive technologies in Brazil. In it, she links the limited supply of products to the lack of incentives and funding for R&D and manufacturing in the country.<\/p>\n

\u201cSadly, Brazilian-made assistive technology is still quite limited,\u201d says Linamara Rizzo Battistella, a physiatrist and director of the Physical Therapy and Rehabilitation Institute (IMREA) at the USP School of Medicine\u2019s teaching hospital, and a former state secretary for disability rights.<\/p>\n

Battistella believes Brazil has strong innovation hubs and the capabilities to produce and deliver the assistive technologies patients require. At the same time, she sees Brazil\u2019s public healthcare system, with its significant purchasing power, as a major opportunity for domestic suppliers. \u201cAnd yet we\u2019re still heavily dependent on imports, both for raw materials and components,\u201d she notes.<\/p>\n

According to Battistella, Brazilian research centers need to collaborate more closely with industry, so that innovation and development at local labs can become market-ready products offered through the SUS. \u201cRight now, there\u2019s not enough conversation between the public sector and private companies,\u201d Battistella adds.<\/p>\n

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L\u00e9o Ramos Chaves\u2009\/\u2009Revista Pesquisa FAPESP<\/span>A researcher at USP\u2019s Polytechnic School working on a robotic lower-limb exoskeletonL\u00e9o Ramos Chaves\u2009\/\u2009Revista Pesquisa FAPESP<\/span><\/p><\/div>\n

Meeting real-world needs
\n<\/strong>Bridging this divide is one of the core goals of CTecvida, based at USP. \u201cWe hope to bring together the right players to make competitive, high-quality assistive tech a reality,\u201d says Arturo Forner-Cordero, an engineer who heads the Biomechatronics Lab at USP\u2019s Polytechnic School (POLI).<\/p>\n

CTecvida\u2019s partners include USP\u2019s S\u00e3o Carlos School of Engineering (EESC-USP), the Institute for Technological Research (IPT), the S\u00e3o Paulo State Office for Disability Rights, the inclusion-focused Instituto Mara Gabrilli, and the startup Voltta Fitness. \u201cWe\u2019re working to develop technology that truly meets user needs,\u201d says Forner-Cordero. \u201cAnd we want to bring in manufacturers who can deliver these innovations to the market.\u201d<\/p>\n

CTecvida\u2019s current projects at POLI and EESC include two robotic exoskeletons for the lower limbs, designed for people with mobility impairments due to stroke, Parkinson\u2019s disease, or spinal cord injuries. Unlike traditional exoskeletons developed in Europe and the US\u2014large systems that perform all movement for the user\u2014the Brazilian models are compact and designed to combine the user\u2019s effort with mechanical assistance. The key is smart software that interprets the user\u2019s intent to move and activates the system to assist as needed (see<\/em> Pesquisa FAPESP issue no. 301<\/em><\/a>).<\/p>\n

The CTecvida team is now developing modular exoskeletons so users can buy just the components they need\u2014whether that\u2019s support at the knee, ankle, or both\u2014rather than a one-size-fits-all device.<\/p>\n

Key to this strategy, says Forner-Cordero, is making sure these modules are interoperable\u2014so components can be mixed and matched across exoskeletons from different manufacturers. To make that happen, the team plans to establish industry-wide standards and technical specifications for the modular parts, ensuring plug-and-play compatibility across brands. Forner-Cordero outlined safety and design requirements for modular exoskeleton systems in papers presented at the 6th<\/sup> IEEE International Conference on Biomedical Robotics and Biomechatronics back in 2016. More recently, test results from the exoskeleton project were published in IEEE Transactions on Medical Robotics and Bionics.<\/p>\n

CTecvida is also developing modular wheelchairs designed to improve comfort at a competitive cost. The project is being led by the Lightweight Structures Lab at IPT\u2019s Advanced Materials Unit (LEL-UNMA) in S\u00e3o Jos\u00e9 dos Campos, in collaboration with IMREA. This project has been structured into three phases.<\/p>\n

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Leandro Aparecido da Silva Albino\u2009\/\u2009IPT<\/span>A modular wheelchair designed at IPT in S\u00e3o Jos\u00e9 dos CamposLeandro Aparecido da Silva Albino\u2009\/\u2009IPT<\/span><\/p><\/div>\n

The first, currently underway, is designing a conventional wheelchair that uses more ergonomic materials\u2014yet remains affordable and priced in line with SUS procurement standards. This will include replacing standard polymer components like the seat, backrest, and armrest with anatomically contoured parts made from thermoformable foams\u2014composite polymer materials reinforced with natural or synthetic fibers. \u201cThese materials conform to body shape and significantly improve comfort,\u201d says Alessandro Guimar\u00e3es, an industrial engineer and LEL\u2019s technical lead.<\/p>\n

But switching to more advanced materials can raise costs. To work around this, the team is using structural modeling to analyze stress points so only the most critical areas use premium materials, while others are built with cost-saving alternatives. \u201cWe\u2019ll reserve the best materials for where they matter most and use more affordable ones elsewhere,\u201d Guimar\u00e3es explains.<\/p>\n

In phase two, the LEL team plans to design a modular wheelchair frame that can accept different parts as the patient\u2019s condition evolves. A single frame could accommodate a growing child over time, helping families cut costs,\u201d Guimar\u00e3es adds. In the final phase, the wheelchair will be integrated with the modular exoskeletons from POLI and EESC, enabling users to switch between sitting and standing devices on their own. \u201cUsers will be able to don their exoskeletons while seated, stand up to move, and then sit back down to remove the device\u2014all on their own,\u201d Forner-Cordero envisions.<\/p>\n

The story above was published with the title “Affordable assistive products<\/strong>” in issue in issue 350 of april\/2025.<\/p>\n

Projects<\/strong>
\n1.<\/strong> Multidisciplinary Center for the Development of Assistive Technology (CMDTA) (n\u00ba 24\/01132-2<\/a>); Grant Mechanism<\/strong> Science Centers for Development (CCD); Principal Investigator<\/strong> Carlos Roberto Grandini (UNESP); Investment<\/strong> R$3,483,566.25.
\n2.<\/strong> Assistive Technologies Center for Activities in Daily Life (n\u00ba 24\/01120-4<\/a>); Grant Mechanism<\/strong> Science Centers for Development (CCD); Principal Investigator<\/strong> Arturo Forner-Cordero (USP); Investment<\/strong> R$4,317,141.84.<\/p>\n

Scientific articles<\/strong>
\nSANTOS, J. V. C. et al.<\/em> Numerical analysis of a composite leg prosthesis<\/a>. Irf-2018 Proceedings of the 6th International Conference on Integrity-reliability-failure<\/strong>. pp. 77\u201384. 2018.
\nPORSANI, R. N. & PASCHOARELLI, L. C. Emo\u00e7\u00e3o e est\u00e9tica: An\u00e1lise de inv\u00f3lucros customiz\u00e1veis de pr\u00f3teses transtibiais por meio da ferramenta GEW<\/a>. Educa\u00e7\u00e3o Gr\u00e1fica<\/strong>. Vol. 24, no. 3, pp. 386\u2013402. Dec. 2020.
\nRODRIGUES, A. A. et al.<\/em> Perspectiva econ\u00f4mica do mercado de inova\u00e7\u00e3o em tecnologia assistiva: Cen\u00e1rio nacional e proje\u00e7\u00f5es mundiais<\/a>. Jornal Brasileiro de Economia da Sa\u00fade<\/strong>. Vol. 16 , no. 1, pp. 65\u20139. Apr. 2024.
\nSOUZA, R. S. et al.<\/em> Modular exoskeleton design: Requirement engineering with KAOS<\/a>. 2016 6th IEEE International Conference on Biomedical Robotics and Biomechatronics<\/strong>. pp. 978\u201383. July 2016.
\nSOUIT, C. et al<\/em>. Design of a lower limb exoskeleton for experimental research on gait control<\/a>. 2016 6th IEEE International Conference on Biomedical Robotics and Biomechatronics<\/strong>. pp. 1098\u2013103. 2016.
\nPARIK-AMERICANO, P. et al<\/em>. Lower limb exoskeleton during gait and posture: Objective and subjective assessment procedures with minimal instrumentation<\/a>. IEEE Transactions on Medical Robotics and Bionics<\/strong>. Vol. 5, no. 4, pp. 1025\u201336. 2023.<\/p>\n

Master’s dissertation<\/strong>
\nMACEDO, M. A. O efeito de um novo prot\u00f3tipo de pr\u00f3tese externa de joelho monoc\u00eantrico em a\u00e7o inoxid\u00e1vel e polipropileno na marcha e capacidade funcional de idosos amputados transfemoral<\/a>. Unesp. 2024.<\/p>\n

Book<\/strong>
\nARRUDA, A. J. V. et al<\/em>. Design, Artefato e Sistema Sustent\u00e1vel.<\/a> Blucher<\/strong>. 2018.<\/p>\n","protected":false},"excerpt":{"rendered":"Prototype devices created by new research centers in search of greater cost-benefit","protected":false},"author":538,"featured_media":0,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"_acf_changed":false,"_exactmetrics_skip_tracking":false,"_exactmetrics_sitenote_active":false,"_exactmetrics_sitenote_note":"","_exactmetrics_sitenote_category":0,"footnotes":""},"categories":[169],"tags":[228,243,2413],"coauthors":[1346],"class_list":["post-566704","post","type-post","status-publish","format-standard","hentry","category-technology","tag-engineering","tag-innovation","tag-technology"],"acf":[],"_links":{"self":[{"href":"https:\/\/revistapesquisa.fapesp.br\/en\/wp-json\/wp\/v2\/posts\/566704","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/revistapesquisa.fapesp.br\/en\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/revistapesquisa.fapesp.br\/en\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/revistapesquisa.fapesp.br\/en\/wp-json\/wp\/v2\/users\/538"}],"replies":[{"embeddable":true,"href":"https:\/\/revistapesquisa.fapesp.br\/en\/wp-json\/wp\/v2\/comments?post=566704"}],"version-history":[{"count":3,"href":"https:\/\/revistapesquisa.fapesp.br\/en\/wp-json\/wp\/v2\/posts\/566704\/revisions"}],"predecessor-version":[{"id":566766,"href":"https:\/\/revistapesquisa.fapesp.br\/en\/wp-json\/wp\/v2\/posts\/566704\/revisions\/566766"}],"wp:attachment":[{"href":"https:\/\/revistapesquisa.fapesp.br\/en\/wp-json\/wp\/v2\/media?parent=566704"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/revistapesquisa.fapesp.br\/en\/wp-json\/wp\/v2\/categories?post=566704"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/revistapesquisa.fapesp.br\/en\/wp-json\/wp\/v2\/tags?post=566704"},{"taxonomy":"author","embeddable":true,"href":"https:\/\/revistapesquisa.fapesp.br\/en\/wp-json\/wp\/v2\/coauthors?post=566704"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}