Shape fidelity and sterility assessment of 3D printed polycaprolactone and hydroxyapatite scaffolds

AbstractPolycaprolactone (PCL) and hydroxyapatite (HA) composite are widely used in tissue engineering (TE). They are fit to being processed with three-dimensional (3D) printing technique to create scaffolds with verifiable porosity. The current challenge is to guarantee the reliability and reproducibility of 3D printed scaffolds and to create sterile scaffolds which can be used for in vitro cell cultures. In this context it is important for successful cell culture, to have a protocol in order to evaluate the sterility of the printed scaffolds. We proposed a systematic approach to sterilise 90%PCL-10%HA pellets using a 3D bioprinter before starting the printing process. We evaluated the printability of PCL-HA composite and the shape fidelity of scaffolds printed with and without sterilised pellets varying infill pattern, and the sterility of 3D printed scaffolds following the method established by the United States Pharmacopoeia. Finally, the thermal analyses supported by the Fourier Transform Infrared Spectroscopy were useful to verify the stability of the sterilisation process in the PCL solid state with and without HA. The results show that the use of the 3D printer, according to the proposed protocol, allows to obtain sterile 3D PCL-HA scaffolds suitable for TE applications such as bone or cartilage repair

Understanding the potentiality of accelerator based-boron neutron capture therapy for osteosarcoma: Dosimetry assessment based on the reported clinical experience

Background: Osteosarcoma is the most frequent primary malignant bone tumour, and its incidence is higher in children and adolescents, for whom it represents more than 10% of solid cancers. Despite the introduction of adjuvant and neo-adjuvant chemotherapy that markedly increased the success rate in the treatment, aggressive surgery is still needed and a considerable percentage of patients do not survive due to recurrences or early metastases. Boron Neutron Capture Therapy (BNCT), an experimental radiotherapy, was investigated as a treatment that could allow a less aggressive surgery by killing infiltrated tumour cells in the surrounding healthy tissues. BNCT requires an intense neutron beam to ensure irradiation times of the order of 1h. In Italy, a Radio Frequency Quadrupole (RFQ) proton accelerator has been designed and constructed for BNCT, and a suitable neutron spectrum was tailored by means of Monte Carlo calculations. This paper explores the feasibility of BNCT to treat osteosarcoma using this neutron source based on accelerator. Methods: The therapeutic efficacy of BNCT was analysed evaluating the dose distribution obtained in a clinical case of femur osteosarcoma. Mixed field dosimetry was assessed with two different formalisms whose parameters were specifically derived from radiobiological experiments involving in vitro UMR-106 osteosarcoma cell survival assays and boron concentration assessments in an animal model of osteosarcoma. A clinical case of skull osteosarcoma treated with BNCT in Japan was re-evaluated from the point of view of dose calculation and used as a reference for comparison. Results: The results in the case of femur osteosarcoma show that the RFQ beam would ensure a suitable tumour dose painting in a total irradiation time of less than an hour. Comparing the dosimetry between the analysed case and the treated patient in Japan it turns out that doses obtained in the femur tumour are at least as good as the ones delivered in the skull osteosarcoma. The same is concluded when the comparison is carried out taking into account osteosarcoma irradiations with photon radiation therapy. Conclusions: The possibility to apply BNCT to osteosarcoma would allow a multimodal treatment consisting in neo-adjuvant chemotherapy, high-LET selective radiation treatment and a more conservative surgery.Fil: Bortolussi, Silva. University of Pavia; ItaliaFil: Postuma, Ian. University of Pavia; ItaliaFil: Protti, Nicoletta. University of Pavia; ItaliaFil: Provenzano, Lucas. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Comisión Nacional de Energía Atómica; ArgentinaFil: Ferrari, Cinzia. University of Pavia; ItaliaFil: Cansolino, Laura. University of Pavia; ItaliaFil: Dionigi, Paolo. University of Pavia; ItaliaFil: Galasso, Olimpio. University of Catanzaro; ItaliaFil: Gasparini, Giorgio. University of Catanzaro; ItaliaFil: Altieri, Saverio. University of Pavia; ItaliaFil: Miyatake, Shin Ichi. Osaka Medical College; JapónFil: González, Sara Josefina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Comisión Nacional de Energía Atómica; Argentin

Potential applications of nanocellulose-containing materials in the biomedical field

Because of its high biocompatibility, bio-degradability, low-cost and easy availability, cellulose finds application in disparate areas of research. Here we focus our attention on the most recent and attractive potential applications of cellulose in the biomedical field. We first describe the chemical/structural composition of cellulose fibers, the cellulose sources/features and cellulose chemical modifications employed to improve its properties. We then move to the description of cellulose potential applications in biomedicine. In this field, cellulose is most considered in recent research in the form of nano-sized particle, i.e., nanofiber cellulose (NFC) or cellulose nanocrystal (CNC). NFC is obtained from cellulose via chemical and mechanical methods. CNC can be obtained from macroscopic or microscopic forms of cellulose following strong acid hydrolysis. NFC and CNC are used for several reasons including the mechanical properties, the extended surface area and the low toxicity. Here we present some potential applications of nano-sized cellulose in the fields of wound healing, bone-cartilage regeneration, dental application and different human diseases including cancer. To witness the close proximity of nano-sized cellulose to the practical biomedical use, examples of recent clinical trials are also reported. Altogether, the described examples strongly support the enormous application potential of nano-sized cellulose in the biomedical field

Lithium halide filled carbon nanocapsules: Paving the way towards lithium neutron capture therapy (LiNCT)

Neutron capture therapy (NCT) is a form of radiotherapy that exploits the potential of some specific isotopes to capture thermal neutrons and subsequently yield high linear energy transfer (LET) particles, suitable for cancer treatment. Recently, relevant technological improvements have been made in terms of accelerators as suitable neutron sources for NCT at hospitals. However, low selective delivery of current drugs to cancer cells remains as the main challenge for successful clinical application of NCT. This work presents an innovative and previously unexplored approach for the design of nanotherapeutic NCT agents. Herein, a new concept based on carbon nanomaterials that seal 6Li active NCT nuclides is investigated. The 6Li active species are located in the inner cavity of the nanocarrier (carbon nanohorns or carbon nanotubes) and therefore, completely protected from the biological environment, avoiding toxicity and degradation. After encapsulation of the active cargo, the external surface of the nanocarrier is modified for improved biocompatibility. The developed 6Li-filled carbon nanohorns offered the possibility to explore 6Li compounds as active NCT agents by delivering therapeutic doses to cancer cells. We envisage that nanoencapsulation of 6Li can trigger the successful development and implementation of Lithium Neutron Cancer Therapy (LiNCT).G. T. acknowledges funding from ERC Consolidator Grant NEST (725743). G.G. gratefully acknowledges the funding by the Portuguese Science Foundation (FCT) for Programme Stimulus of Scientific Employment – Individual Support (CEECIND/01913/2017), financial support of project CARBONCT (2022.03596.PTDC), TEMA UIDB/00481/2020 and UIDP/00481/2020; and CENTRO-01-0145-FEDER-022083 - Centro Portugal Regional Operational Programme (Centro2020), under the PORTUGAL 2020 Partnership Agreement, through the European Regional Development Fund. In addition, support through the project IF/00894/2015 and within the scope of the project CICECO-Aveiro Institute of Materials, UIDB/50011/2020, UIDP/50011/2020 & LA/P/0006/2020, financed by national funds through the FCT/MEC (PIDDAC) is gratefully acknowledged. We acknowledge funding by INFN (CSN5)-project ENTER_BNCT. ICMAB and ICN2 acknowledge financial support from the Spanish Ministry of Economy and Competitiveness (Spain), through the “Severo Ochoa” Programme for Centres of Excellence in R&D (CEX2019-000917-S and CEX2021-001214-S respectively). ICN2 is supported by CERCA programme. We acknowledge funding from Generalitat de Catalunya (2021-SGR-00439, 2017 SGR 327). M.Ll. has carried out this work in the framework of the Doctoral Degree Program in Materials Science of the Universitat Autònoma de Barcelona. We acknowledge fruitful discussions with Manuel Altabas and support with the XPS analysis by Guillaume Sauthier.With funding from the Spanish government through the ‘Severo Ochoa Centre of Excellence’ accreditation (CEX2019-000917-S).Peer reviewe

Rational design of gold nanoparticles functionalized with carboranes for application in Boron Neutron Capture Therapy

In this paper we propose a bottom-up approach to obtain new boron carriers built with ortho-carborane functionalized gold nanoparticles (GNPs) for applications in Boron Neutron Capture Therapy. The interaction between carboranes and the gold surface was assured by one or two SH-groups directly linked to the boron atoms of the B10C2 cage. This allowed obtaining stable, non toxic systems, though optimal biological performance was hampered by low solubility in aqueous media. To improve cell uptake, the hydrophilic character of carborane functionalized GNPs was enhanced by further coverage with an appropriately tailored diblock copolymer (PEO-b-PCL). This polymer also contained pendant carboranes to provide anchoring to the pre-functionalized GNPs. In vitro tests, carried out on osteosarcoma cells, showed that the final vectors possessed excellent biocompatibility joint to the capacity of concentrating boron atoms in the target, which is encouraging evidenced to pursue applications in vivo

Characterization of a Bioink Combining Extracellular Matrix-like Hydrogel with Osteosarcoma Cells: Preliminary Results

Three-dimensional (3D) bioprinting allows the production of artificial 3D cellular microenvironments thanks to the controlled spatial deposition of bioinks. Proper bioink characterization is required to achieve the essential characteristics of printability and biocompatibility for 3D bioprinting. In this work, a protocol to standardize the experimental characterization of a new bioink is proposed. A functionalized hydrogel based on gelatin and chitosan was used. The protocol was divided into three steps: pre-printing, 3D bioprinting, and post-printing. For the pre-printing step, the hydrogel formulation and its repeatability were evaluated. For the 3D-bioprinting step, the hydrogel-printability performance was assessed through qualitative and quantitative tests. Finally, for the post-printing step, the hydrogel biocompatibility was investigated using UMR-106 cells. The hydrogel was suitable for printing grids with good resolution from 4 h after the cross-linker addition. To guarantee a constant printing pressure, it was necessary to set the extruder to 37 °C. Furthermore, the hydrogel was shown to be a valid biomaterial for the UMR-106 cells’ growth. However, fragmentation of the constructs appeared after 14 days, probably due to the negative osteosarcoma-cell interference. The protocol that we describe here denotes a strong approach to bioink characterization to improve standardization for future biomaterial screening and development

Boron concentration measurements by alpha spectrometry and quantitative neutron autoradiography in cells and tissues treated with different boronated formulations and administration protocols

The possibility to measure boron concentration with high precision in tissues that will be irradiated represents a fundamental step for a safe and effective BNCT treatment. In Pavia, two techniques have been used for this purpose, a quantitative method based on charged particles spectrometry and a boron biodistribution imaging based on neutron autoradiography. A quantitative method to determine boron concentration by neutron autoradiography has been recentlyset-up and calibrated for the measurement of biological samples, both solid and liquid, in the frame of the feasibility study of BNCT. Thist echnique was calibrated and the obtained results were cross checked with those of α spectrometry,inorderto validatethem. The comparisons were performed using tissues taken from animals treated with different boron administration protocols. Subsequently the quantitative neutron autoradiography was employed to measure osteosarcoma cell samples treated with BPA and with new boronated formulations

An improved neutron autoradiography set-up for 10B concentration measurements in biological samples

tAim: Boron Neutron Capture Therapy (BNCT) is a binary hadrontherapy which exploits theneutron capture reaction in boron, together with a selective uptake of boronated substancesby the neoplastic tissue. There is increasing evidence that future improvements in clinicalBNCT will be triggered by the discovery of new boronated compounds, with higher selectivityfor the tumor with respect to clinically used sodium borocaptate (BSH) and boronopheny-lalanine (BPA).Background: Therefore, a10B quantification technique for biological samples is needed inorder to evaluate the performance of new boronated formulations.Materials and methods: This article describes an improved neutron autoradiography set-upemploying radiation sensitive films where the latent tracks are made visible by properetching conditions.Results: Calibration curves for both liquid and tissue samples were obtained.Conclusions: The obtained calibration curves were adopted to set-up a mechanism to pointout boron concentration in the whole sample

An improved neutron autoradiography set-up for B concentration measurements in biological samples

AimBoron Neutron Capture Therapy (BNCT) is a binary hadrontherapy which exploits the neutron capture reaction in boron, together with a selective uptake of boronated substances by the neoplastic tissue. There is increasing evidence that future improvements in clinical BNCT will be triggered by the discovery of new boronated compounds, with higher selectivity for the tumor with respect to clinically used sodium borocaptate (BSH) and boronophenylalanine (BPA).BackgroundTherefore, a 10B quantification technique for biological samples is needed in order to evaluate the performance of new boronated formulations.Materials and methodsThis article describes an improved neutron autoradiography set-up employing radiation sensitive films where the latent tracks are made visible by proper etching conditions.ResultsCalibration curves for both liquid and tissue samples were obtained.ConclusionsThe obtained calibration curves were adopted to set-up a mechanism to point out boron concentration in the whole sample