Silkothane is a hybrid of silk fibroin and polyurethane that Dialybrid uses to build a vascular access graft for hemodialysis. On September 22, 2026, the Italian company announced a €15 million Series A and the first implant in a patient.
What did Dialybrid announce on September 22, 2026?
The round was led by new investor XGEN Venture, with CDP Venture Capital participating through its Rilancio Fund. The money funds clinical development of the Silkothane Arteriovenous Graft and preclinical work on the same material in other vascular applications. The first patient was implanted by Matteo Tozzi, head of vascular surgery at ASST Sette Laghi and professor at Insubria University in Varese, who coordinates the study.
| Item | Detail |
|---|---|
| Round | Series A, €15 million |
| Investors | XGEN Venture (lead), CDP Venture Capital via the Rilancio Fund |
| Trial design | first-in-human, open-label, single-arm |
| Planned enrolment | 18 adults |
| Sites | 4, all in Italy |
| Follow-up | up to 60 months |
| Interim analyses | 6, 12 and 24 months |
| Patients implanted at announcement | 1 |
| Next public presentation | LSI Europe ’26, Barcelona, September 29, 2026 |
Source: Dialybrid press release, September 22, 2026.
Why is vascular access the weak point of hemodialysis?
Under the KDOQI guidelines cited by the company, the ideal access delivers enough flow for the prescribed dialysis, is easy to cannulate, lasts, and causes few complications. A native arteriovenous fistula is more durable but must mature before use. A synthetic graft gets patients onto dialysis sooner but lasts less and carries a higher infection risk. Long fistula maturation goes hand in hand with high catheter use.
Conventional grafts are prone to intimal hyperplasia, stenosis, thrombosis and infection. The narrowing typically forms at the venous anastomosis or in the outflow vein just beyond it.
How should the “60% fail within a year” figure be read?
The release says about 60% of grafts and 40% of fistulas fail in the first year. Both figures match the loss of primary patency reported in the meta-analyses, meaning the time an access stays open with no intervention. They do not measure abandonment. Secondary, or cumulative, patency runs until the access is abandoned and is not interrupted by the surgical or radiological procedures used to keep it open or restore it.
| Access | 1-year primary patency | 1-year secondary patency | Source |
|---|---|---|---|
| Native AV fistula | 64% | 79% | Bylsma et al., EJVES, 2017 |
| ePTFE graft | 41% | 70% | 2020 meta-analysis reported by Riber et al., Frontiers in Cardiovascular Medicine, 2024 |
The fistula meta-analysis pooled 318 studies and 62,712 accesses. It found that only 26% of fistulas were mature at six months, 21% were abandoned without ever being used, and not every fistula reported as patent could be confirmed as usable for dialysis. The 2020 graft meta-analysis put 12-month primary patency at 41% and secondary patency at 70%. Open is not the same as working, and the distinction will matter when Silkothane data arrive.
Several authors of the fistula meta-analysis list Humacyte as their affiliation, and Humacyte is developing a bioengineered vessel for dialysis access. That does not make the figures wrong, but readers should know it.
How does a silk-polyurethane graft work?
In Silkothane, silk fibroin is the biocompatible, resorbable component that supports the body’s own tissue remodelling. Polyurethane is elastic, does not resorb, and provides durability and long-term stability. The graft has three layers and is semi-resorbable, integrating gradually into the patient’s body. The goal is to combine the early cannulation of synthetic grafts with the long-term patency of native fistulas.
The material is electrospun using a proprietary process that, according to the company, allows mechanical properties to be tuned precisely. In electrospinning, a polymer solution is pushed through a needle connected to a high-voltage supply. The electric field overcomes surface tension, forms a jet and deposits very fine fibres on a grounded collector. To make a tube, the fibre layers are spun onto a cylindrical mandrel.
A research project called SILKELASTOGRAFT, run by Politecnico di Milano’s biomechanics group, Bioengineering Laboratories and the Mario Negri institute, used Silkothane to pursue a dialysis graft whose compliance matches the patient’s own vessels. Compliance is how much a vessel wall stretches under blood pressure.
What did the animal study show?
In a 2020 proof-of-concept study in Advanced Healthcare Materials, grafts were implanted between the common carotid artery and the external jugular vein of nine sheep, examined at 30, 60 and 90 days, three animals per group. There were no graft-related complications. Eight of nine animals had patent grafts with no intervention at examination, and the single thrombosis was attributed to surgery.
Tissue analysis found inflammation and a pseudointima inside the graft, mainly at the venous end, although the narrowing never impaired function. Endothelial cells had begun to line the surface. The venous end is where human grafts usually narrow, and 90 days cannot show how that layer evolves.
The limits are plain: nine animals, 90 days at most, and company-linked authors. The paper discloses that two authors were Bioengineering Laboratories employees, one also a shareholder, and two were consultants to the company.
What can an 18-patient first-in-human trial prove?
A first-in-human study checks that a device can be implanted and used safely. It is not designed to show that it beats existing options. Dialybrid’s study is open-label and single-arm, with no comparison group, and will measure safety and performance. The release does not name primary endpoints or inclusion criteria.
Tozzi said he was very satisfied with how easily the graft was implanted in the first patient. If it works as intended, he said, it could offer faster cannulation than fistulas and longer durability than grafts on the market. That is one surgeon’s impression of one case, plus a hypothesis. The outcomes that matter are time to first dialysis through the graft, patency, infections, and the number of procedures needed to keep it open.
Tozzi also led the first-in-human study of aXess, a graft made by Xeltis, a Dutch company based in Eindhoven. In 20 patients at six European sites, all grafts were patent at six months, with 80% primary and 100% secondary patency, one thrombosis, no infections and four re-interventions. Encouraging, but in twenty people, at six months, with no head-to-head comparison. Xeltis then moved to a pivotal trial that in 2023 was enrolling up to 110 patients at up to 25 sites in nine EU countries.
Where does Silkothane sit in the race to fix dialysis access?
| Approach | Example | Status | Source |
|---|---|---|---|
| Synthetic graft | ePTFE, current standard | 41% primary and 70% secondary patency at 12 months | 2020 meta-analysis via Frontiers, 2024 |
| Graft built around endogenous tissue restoration | Xeltis aXess | first-in-human in 20 patients; pivotal trial under way in 2023 | J Vasc Access, 2024; Endovascular Today, 2023 |
| Bioengineered human acellular vessel | Humacyte ATEV (Symvess) | US-approved for extremity vascular trauma; dialysis filing planned for November 2026 | Endovascular Today, September 15, 2026 |
| Semi-resorbable silk-polyurethane graft | Dialybrid Silkothane | first patient implanted, 18 planned | Dialybrid, September 22, 2026 |
Symvess is approved in the US for adults with extremity arterial injury who need urgent revascularisation when a vein graft is not feasible. Humacyte expects to file for dialysis access as a second indication in November 2026. Its V007 Phase 3 trial in dialysis access enrolled 242 patients. The four approaches differ in design, patient populations and endpoints, so their figures cannot be compared directly.
Why is Italy an unusual test bed?
Italy uses few arteriovenous grafts. The Italian Society of Nephrology’s vascular access study group put them at 1% to 5% of accesses, reflecting a different approach from other countries. It reserved grafts for patients without usable superficial veins, for repairing a fistula, or as an alternative to a tunnelled catheter when life expectancy justifies it. That consensus dates from 2012. Registry data for 2023 put Italy’s dialysis prevalence at 771 patients per million inhabitants.
The whole first-in-human study runs in Italian centres, backed by two Italian investors. Dialybrid was founded in August 2020 by Francesco Greco, who set up Bioengineering Laboratories in 2001 and sold it to the Delta Med group in 2018. Its products build on BEL’s research. Its first €300,000 came from a co-investment by BEL and LIFTT, an investment company set up by the Compagnia di San Paolo foundation and Politecnico di Torino. For comparison, the PRIMA retinal implant reached CE marking after a multicentre study of 38 patients at 17 European sites published in the New England Journal of Medicine. Any CE route for Silkothane runs through the same EU medical device rules.
FAQ
What is Silkothane?
A patented hybrid of silk fibroin and polyurethane, made by electrospinning. The fibroin resorbs and supports tissue remodelling; the polyurethane stays and provides stability.
Can the Dialybrid graft be used today?
No. It is in a first-in-human study planned for 18 patients at four Italian sites and has yet to complete its route to regulatory approval.
How is a graft different from a fistula?
A fistula joins a patient’s own artery and vein; it lasts longer but must mature. A graft can be used sooner but lasts less and carries a higher infection risk.
Who funded Dialybrid?
XGEN Venture led the €15 million Series A, with CDP Venture Capital through its Rilancio Fund.
When will human results be available?
The protocol includes interim analyses at 6, 12 and 24 months and follow-up of up to 60 months. No dates have been given.
Sources
- Dialybrid press release via GlobeNewswire, September 22, 2026
- Forbes Italia, September 22, 2026
- LIFTT press release on Dialybrid, August 4, 2020
- European Commission, CORDIS, project no. 833936 (SAG)
- Politecnico di Milano, SILKELASTOGRAFT project site
- Riboldi et al., Advanced Healthcare Materials, September 2020
- Bylsma et al., European Journal of Vascular and Endovascular Surgery, October 2017
- Riber et al., Frontiers in Cardiovascular Medicine, February 2024
- Tozzi et al., The Journal of Vascular Access, online February 2024 (aXess-FIH)
- Endovascular Today, May 5, 2023 and September 15, 2026
- Humacyte, full-year 2024 results (March 28, 2025) and Q2 2025 results
- Tazza et al., The Journal of Vascular Access, 2012 (Italian Society of Nephrology)
- Giornale Italiano di Nefrologia, 9th GPDP-SIN census, August 2025 (RIDT 2023 data)
- INT News, PRIMA retinal implant, July 27, 2026
