From waste to value: CELLS research among silk, sustainability and nanofibres

I started out as a mechanical engineer, but at a certain point I realised that “classical” mechanics was not what truly fascinated me. I felt the need to go beyond, to look at things more closely, to understand what happens at the nanometric scale. I was fascinated by the idea of entering matter, of exploring its smallest structures. 

In those very years, the nanoscale was beginning to find applications in bioengineering, and that perspective literally opened up a new world for me. I therefore chose to change direction and follow a bioengineering path. I completed my PhD here at Politecnico and, step by step, I stayed on. First as a postdoctoral researcher, then as a researcher, and finally as a professor. 

CELLS stands for Circular Economy Lab for Life Sciences. It is an acronym that I find beautiful. It is not directly related to cells, but cells, and life, are our target.
We do not culture cells: we develop materials that can be studied and used in other laboratories for cellular applications. We identify new materials that have applications in the life sciences. The idea is simple: identify waste materials and transform them into something new, functional, with a concrete application.

It is an interdepartmental laboratory. It originates from the Department of Electronics, Information and Bioengineering and also involves the Department of Chemistry, Materials and Chemical Engineering and the Department of Mechanical Engineering, which host part of the instrumentation and contribute to research activities. The initial funding, received from Fondazione Politecnico, leader of spoke 3 of the MUSA project within the framework of PNRR funding, was intended exclusively for the purchase of instrumentation, and this led us to build a truly shared model: we pooled expertise, equipment and spaces, creating a distributed infrastructure that integrates three different disciplinary areas. 

We have three “souls” that also identify three different phases of the processes carried out in the laboratory: Extract, in which we recover waste materials; Function, where we study their properties and confer new functionalities through chromatographs, systems for peptide synthesis and thermogravimetry; and finally Shape, in which, through electrospinning and 3D bioprinting and bioreactors for peptide synthesis, we give shape to the material.

Electrospinning is a technique used to produce very thin fibres starting from a polymer solution. A high electric voltage is applied between a syringe containing the (bio)polymer and a collector. The electric field “pulls” the liquid, forming a very fine jet that stretches in the air. During its path, the solvent evaporates and solid nanofibres of the initial (bio)polymer are deposited on the collector. 

The material is, for example, sericin, which is hydrophilic, that is, “water-friendly”; we obtain membranes that dissolve upon contact with moistened skin, contributing to a moisturising and smoothing effect. 

My decision to pursue research was driven by the challenge of transforming natural materials into high-performance structures. After specialising in electrospinning during my previous studies in the Czech Republic, I was looking for a laboratory where I could apply this expertise to concrete sustainability-related challenges. 

At CELLS, I found a context in which electrospinning is not just a technique, but a tool for giving new life to waste biopolymers. I saw the opportunity to use it as a bridge: to take a biological by-product and redesign it as a high value-added material. Joining Prof. Vesentini’s group allowed me to tackle this technical challenge in a strongly multidisciplinary environment. 

My typical day involves extremely precise preparation: calculating the exact concentrations of sericin and fibroin solutions and rigorously monitoring the stability of the Taylor cone at the tip of the needle.

It is a process that requires both technical intuition and systematic control. I spend a great deal of time precisely adjusting voltage and flow rate, not only to produce fibres, but to ensure reproducibility and material consistency. Between one electrospinning session and the next, I am often at the characterisation bench, analysing morphology and mechanical properties to ensure that our nanofibrous membranes meet the structural requirements demanded by potential applications. 

Silk is the material we are focusing on, but it is not the only one. Every industrial process that starts from natural raw materials generates waste, and in that waste there is often enormous potential. For example, with the KARATE project, we are recovering keratin from waste products (feathers) of the poultry industry or, within the RICH project, we are studying how to enhance the protein content of black soldier fly larvae. Recently we have been working on other by-products of natural origin, for example shrimp shells that contain chitosan, a sugar with very interesting biological and functional properties. Or lignin from the paper industry, which is usually compacted and burned. The idea we are working on is to combine sericin, chitosan and lignin, to which zein, a protein derived from maize and little used, can be added, to develop a new food film. 

The goal is ambitious: to create a compostable alternative to traditional plastic films.
If we were able to produce a film that, instead of ending up in plastic waste, could be disposed of in organic compost, it would be a radical change in the packaging sector. 

We will not solve the global plastic problem, but food packaging is an area where we can make a concrete contribution. 

Applications are growing and, for those working in the laboratory, they take on a personal meaning. 

I am currently focusing on optimising the electrospinning of sericin. What makes this project significant is its cross-sector applicability: we are developing solutions for high-end bioactive cosmetics, medical-grade wound dressings and functional and sustainable food packaging. Transforming a biological by-product into a sophisticated material capable of protecting a wound or improving skin health represents exactly the kind of circular science that motivates me.

Ritessere was a decisive step for us. In 2022 we obtained funding from Fondazione Cariplo within the call dedicated to the circular economy. 

The RITESSERE project (Silk Sericin Materials from Textile Industry By-Products) was created with a clear objective: to demonstrate that sericin, traditionally discarded as waste in silk textile production, can become the basis for a new generation of high technological value materials. The support received made it possible to consolidate the laboratory’s scientific infrastructure, strengthen collaboration between Politecnico di Milano, Università di Milano-Bicocca and CREA, and develop three concrete application lines: cosmetics, biomedical and sustainable packaging. Sericin-only patches were the first tangible result. 

Writing a project is one thing. Seeing the patches dissolve exactly as we had imagined is another. It was an enormous satisfaction. 

But the importance of RITESSERE goes beyond the single product: it marked the transition from an intuition to a structured circular research platform. It is not just about creating a new material. It is about rethinking the entire silk production cycle: recovering what is discarded and transforming it into something that re-enters the economic system with higher value. 

The travelling exhibition entitled “RITESSERE: a thread between tradition and innovation”, inaugurated in March 2025, has reached several Italian cities, including Concorezzo, Padua and in the future also Milan, bringing the exhibition to places where silk has effectively shaped the social and economic context (Concorezzo is still a relevant hub for ribbon manufacturing) and carrying with it the message of sustainability and circular economy linked to textile materials, involving schools and families. 

We wanted to show not only results and technologies, but also processes and raw materials: display cases with silkworms used in traditional and innovative ways, panels illustrating the processing stages and, above all, a collective installation. Set-ups like this are not just visually appealing pages, but allow the public to understand how scientific research is connected to history, the environment and communities. 

They are fundamental. The laboratory is designed so that students and PhD candidates can directly use the machines, experiment and learn. This creates expertise, but also responsibility and a sense of belonging. 

There is, however, another important aspect, and that is outreach. The first thing I do when they arrive in the laboratory is take them to outreach events such as the Festival of Engineering. I put them in front of children. It is not a detail, but a precise choice. Because when you see in a child’s eyes that they have understood what you have told them, you feel driven to go on and you realise that you are not only doing research, but contributing to building a different way of looking at the world. 

And perhaps this is precisely the deepest role of young people in CELLS: not only to produce data or publications, but to learn to see value where others see waste and to pass it on to others. 

And it is precisely in daily practice that this education takes on meaning. 

The more deeply I study biopolymers, the more fascinated I become by them, but at the same time they constantly challenge my hypotheses. There was a specific moment in the laboratory when I realised that, by slightly modifying the electrospinning parameters, I could completely change the way protein fibres self-assemble. It was almost surprising to realise that this “waste product” is actually a highly complex biological building block. The inexhaustible potential of the material and the technical obstacles I must overcome to master it are exactly what keep me committed to this path.

This experience has strengthened my identity as a bioengineer committed to sustainability. It has taught me to look at industrial processes not only for what they produce, but also for what they discard.
From a personal point of view, it has made me much more resilient. In research, one learns to consider “failed experiments” as necessary data. My goal for the future is to continue developing sustainable material platforms that demonstrate that it is not necessary to sacrifice performance for environmental responsibility. I want to help ensure that the results achieved in the laboratory reach the real world, transforming the very concept of “waste” into something that belongs to the past.

Yes, but with a well-defined role. Our contribution is scientific and technological: the laboratory provides advanced instrumentation and interdisciplinary expertise, from electron microscopy to structural analyses, helping companies better understand their materials, optimise them and validate them. 

What we offer is know-how and speed. I have understood that for a company it is essential to have quick answers: this is our value. 

In this sense, CELLS functions as a technology transfer platform, a place where academic research and the production world can meet, test ideas, reduce the risk of innovation and build sustainable solutions. 

We are not an industrial production centre, but an environment where ideas take shape and mature. Our task is to bring together expertise, tools and people, creating the conditions for virtuous solutions to emerge for the territory and for companies. 

The first thing that comes to mind is to go to Padua, to the Museo Esapolis. It is a museum dedicated to insects, accessed through corridors that contain collections of cocoons from different regions of Italy and from Lyon (another historically very important area in Europe for silk production) and that tell how deeply silk has been linked to human history, to the countryside and to the economy. 

I have been there several times, also with my family. Behind the museum there is the CREA sericulture laboratory, our partner in the RITESSERE project, which deals with the conservation of silkworm eggs and is a reference centre for sericulture throughout Italy. Extending our gaze beyond Italy, I would like to go to Japan, where I believe one can breathe silk in every form, from kimonos to small everyday objects. In Japan and China, one can also find cosmetic products made directly from the cocoon. 

And then there is history. Silk production arrived in the 6th century from the Byzantine East and in Italy spread especially in the South and in cities under Byzantine influence such as Catanzaro. In the 12th–13th centuries important Italian silk centres were established, first in Lucca and then in Venice and Genoa thanks to trade with the East. Then, between the 15th and 17th centuries, there was the great development of sericulture especially in Lombardy, Piedmont and Veneto, and Italy became one of the main European producers. 
Areas such as Val di Non or Trentino, today associated with apples, were once cultivated with mulberry trees: the economy revolved around silk. 

Among books, I would recommend two: Le vie italiane della seta, which tells the history of silk in Italy and helps to understand how much this material is intertwined with our culture. The second is Marcovaldo ovvero Le stagioni in città by Italo Calvino. It tells of the contrast between nature and the modern city, highlighting how industrial life makes a harmonious relationship between humans and the environment difficult and how only through a curious spirit can one aspire to a paradigm shift, perhaps a little like what we would like to do in CELLS. 

We warmly thank Professor Vesentini and Bioengineer Hejdová for their openness and for the genuine passion for research they conveyed during the interview. We will continue to follow with enthusiasm the progress of the laboratory and the new challenges that await it, confident that this thread of innovation will continue to weave important stories.