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Leopoldo Sitia,1,* Paola Saccomandi,2,* Leonardo Bianchi,2 Marta Sevieri,1 Cristina Sottani,3 Raffaele Allevi,1 Elena Grignani,3 Serena Mazzucchelli,1 Fabio Corsi1,4 1Department of Biomedical and Clinical Sciences, Università degli studi di Milano, Milan, Italy; 2Department of Mechanical Engineering, Politecnico di Milano, Milan, Italy; 3Environmental Research Center, Istituti Clinici Scientifici Maugeri IRCCS, Pavia, Italy; 4Istituti Clinici Scientifici Maugeri IRCCS, Pavia, Italy*These authors contributed equally to this workCorrespondence: Serena Mazzucchelli, Department of Biomedical and Clinical Sciences, Università degli studi di Milano, via G.B. Grassi 74, Milan, 20157, Italy, Email serena.mazzucchelli@unimi.it Fabio Corsi, Istituti Clinici Scientifici Maugeri IRCCS, via S. Maugeri 10, Pavia, 27100, Italy, Email fabio.corsi@unimi.itIntroduction: Photodynamic Therapy (PDT) is a promising, minimally invasive treatment for cancer with high immunostimulatory potential, no reported drug resistance, and reduced side effects. Indocyanine Green (ICG) has been used as a photosensitizer (PS) for PDT, although its poor stability and low tumor-target specificity strongly limit its efficacy. To overcome these limitations, ICG can be formulated as a tumor-targeting nanoparticle (NP).Methods: We nanoformulated ICG into recombinant heavy-ferritin nanocages (HFn-ICG). HFn has a specific interaction with transferrin receptor 1 (TfR1), which is overexpressed in most tumors, thus increasing HFn tumor tropism. First, we tested the properties of HFn-ICG as a PS upon irradiation with a continuous-wave diode laser. Then, we evaluated PDT efficacy in two breast cancer (BC) cell lines with different TfR1 expression levels. Finally, we measured the levels of intracellular endogenous heavy ferritin (H-Fn) after PDT treatment. In fact, it is known that cells undergoing ROS-induced autophagy, as in PDT, tend to increase their ferritin levels as a defence mechanism. By measuring intracellular H-Fn, we verified whether this interplay between internalized HFn and endogenous H-Fn could be used to maximize HFn uptake and PDT efficacy.Results: We previously demonstrated that HFn-ICG stabilized ICG molecules and increased their delivery to the target site in vitro and in vivo for fluorescence guided surgery. Here, with the aim of using HFn-ICG for PDT, we showed that HFn-ICG improved treatment efficacy in BC cells, depending on their TfR1 expression. Our data revealed that endogenous H-Fn levels were increased after PDT treatment, suggesting that this defence reaction against oxidative stress could be used to enhance HFn-ICG uptake in cells, increasing treatment efficacy.Conclusion: The strong PDT efficacy and peculiar Trojan horse-like mechanism, that we revealed for the first time in literature, confirmed the promising application of HFn-ICG in PDT. Keywords: heavy-ferritin nanocages, indocyanine green, photodynamic therapy, breast cancer, tumor-targeted nanoparticles

Marta Truffi,1 Marta Sevieri,2 Lucia Morelli,3 Matteo Monieri,2 Serena Mazzucchelli,2 Luca Sorrentino,2 Raffaele Allevi,2 Arianna Bonizzi,2 Pietro Zerbi,2 Beatrice Marchini,2 Erika Longhi,2 Gianluca Matteo Sampietro,4 Francesco Colombo,4 Davide Prosperi,3 Miriam Colombo,3 Fabio Corsi2,5 1Nanomedicine and Molecular Imaging Laboratory, Istituti Clinici Scientifici Maugeri IRCCS, Pavia 27100, Italy; 2Department of Biomedical and Clinical Sciences “Luigi Sacco, Università degli studi di Milano, Milano, 20157, Italy; 3NanoBioLab, Department of Biotechnology and Biosciences, Università degli studi di Milano-Bicocca, Milano, 20126, Italy; 4IBD Surgery Unit, ASST Fatebenefratelli Sacco - Ospedale “Luigi Sacco” Polo Universitario, Milano, 20157, Italy; 5Surgery Department, Breast Unit, Istituti Clinici Scientifici Maugeri IRCCS, Pavia, 27100, ItalyCorrespondence: Fabio CorsiSurgery Department, Breast Unit, Istituti Clinici Scientifici Maugeri IRCCS, via Maugeri 4, Pavia 27100, ItalyTel +39 02 5031 9850Fax +39 02 5031 9846Email fabio.corsi@icsmaugeri.itPurpose: Assessment of inflammatory bowel disease (IBD) currently relies on aspecific clinical signs of bowel inflammation. Specific imaging of the diseased bowel regions is still lacking. Here, we investigate mucosal addressin cell adhesion molecule 1 (MAdCAM-1) as a reliable and specific endothelial target for engineered nanoparticles delivering imaging agents to obtain an exact mapping of diseased bowel foci.Materials and Methods: We generated a nanodevice composed of PLGA-PEG coupled with anti-MAdCAM-1 antibody half-chains and loaded with quantum dots (P@QD-MdC NPs). Bowel localization and systemic biodistribution of the nanoconjugate were analyzed upon injection in a murine model of chronic IBD obtained through repeated administration of dextran sulfate sodium salt. Specificity for diseased bowel regions was also assessed ex vivo in human specimens from patients with IBD. Potential for development as contrast agent in magnetic resonance imaging was assessed by preliminary study on animal model.Results: Synthesized nanoparticles revealed good stability and monodispersity. Molecular targeting properties were analyzed in vitro in a cell culture model. Upon intravenous injection, P@QD-MdC NPs were localized in the bowel of colitic mice, with enhanced accumulation at 24 h post-injection compared to untargeted nanoparticles (p< 0.05). Nanoparticles injection did not induce histologic lesions in non-target organs. Ex vivo exposure of human bowel specimens to P@QD-MdC NPs revealed specific recognition of the diseased regions vs uninvolved tracts (p< 0.0001). After loading with appropriate contrast agent, the nanoparticles enabled localized contrast enhancement of bowel mucosa in the rectum of treated mice.Conclusion: P@QD-MdC NPs efficiently detected bowel inflammation foci, accurately following the expression pattern of MAdCAM-1. Fine-tuning of this nanoconjugate with appropriate imaging agents offers a promising non-invasive tool for specific IBD diagnosis.Keywords: polymeric nanoparticles, inflamed bowel, adhesion molecule, targeted imaging

Lucia Salvioni,1 Elisabetta Galbiati,1 Veronica Collico,1 Giulia Alessio,1 Svetlana Avvakumova,1 Fabio Corsi,2,3 Paolo Tortora,1 Davide Prosperi,1 Miriam Colombo1 1Nanobiolab, Department of Biotechnology and Bioscience, University of Milano-Bicocca, 2Biological and Clinical Science Department, University of Milan, Milano, 3Surgery Department, Breast Unit, IRCCS S Maugeri Foundation, Pavia, Italy Background: The discovery of new solutions with antibacterial activity as efficient and safe alternatives to common preservatives (such as parabens) and to combat emerging infections and drug-resistant bacterial pathogens is highly expected in cosmetics and pharmaceutics. Colloidal silver nanoparticles (NPs) are attracting interest as novel effective antimicrobial agents for the prevention of several infectious diseases.Methods: Water-soluble, negatively charged silver nanoparticles (AgNPs) were synthesized by reduction with citric and tannic acid and characterized by transmission electron microscopy, dynamic light scattering, zeta potential, differential centrifuge sedimentation, and ultraviolet–visible spectroscopy. AgNPs were tested with model Gram-negative and Gram-positive bacteria in comparison to two different kinds of commercially available AgNPs.Results: In this work, AgNPs with higher antibacterial activity compared to the commercially available colloidal silver solutions were prepared and investigated. Bacteria were plated and the antibacterial activity was tested at the same concentration of silver ions in all samples. The AgNPs did not show any significant reduction in the antibacterial activity for an acceptable time period. In addition, AgNPs were transferred to organic phase and retained their antibacterial efficacy in both aqueous and nonaqueous media and exhibited no toxicity in eukaryotic cells.Conclusion: We developed AgNPs with a 20 nm diameter and negative zeta potential with powerful antibacterial activity and low toxicity compared to currently available colloidal silver, suitable for cosmetic preservatives and pharmaceutical preparations administrable to humans and/or animals as needed. Keywords: silver nanoparticles, antibacterial activity, long-term effect, nanoparticle toxicity, phase transfer

Two Hamamatsu Photonics silicon photomultipliers (SiPM) with same cell size 50×50 µm2 and different sensitive area (1×1 mm2 vs. 3×3 mm2) have been characterized in charge and time by means of a 409 nm pico-laser. The time resolution was studied for the detection of few photoelectrons. The results obtained are relevant for the employment of SiPM in ring imaging Cherenkov detectors (RICH).

Breast cancer treatment has deeply changed in the last decades, since clinical and oncological cure cannot be achieved without patient's satisfaction in term of aesthetic outcomes. Several methods have been proposed to objectively assess these results. However, Italian breast centers have not yet agreed on measurable, reproducible and validated aesthetic outcome indicators to monitor their performance. The study was designed and conducted by Senonetwork, a not-for-profit association of Italian breast centers. Ten breast centers were selected based on specific eligibility criteria. This multicentre observational prospective study recruited 6515 patients with diagnosis of in situ or invasive breast cancer who underwent breast surgery in the years 2013–2016. Thirteen indicators of aesthetic results and of related quality of care were analyzed. Data collection and analysis were conducted using a common study database. On average, seven out of ten centers were able to collect data on the proposed indicators with a proportion of missing values < 25%. By expert consensus based on study results, some seven indicators have been defined as "mandatory" while the remaining six have been defined as "recommended" because they require further refinement before they can be proposed for monitoring aesthetic outcomes or because there are doubts on the feasibility of data collection. The minimum standard is reached for 5 of 13 indicators. This finding and the wide range between centers reveal that there is ample room for improvement. From the present study useful measurable aesthetic parameters have emerged, leading to the definition of target objectives that breast centers can use for benchmarking and improvement of quality of care. [ABSTRACT FROM AUTHOR]