Francesco Tessarolo

Steam composition, defined as the fraction of non-condensable gases (NCGs) in the steam, is an essential parameter to ensure the efficacy and reliability of the steam sterilisation process. Standard EN 285:2015 + A1:2021 defines an operative method for measuring NCG fraction (NCG%) in the steriliser steam pipes, but lacks specifications about the process profile, timing and volume of condensate, and environmental conditions. This study aimed to quantify the effects of this lack of specifications on NCG% measured values to enable a more effective and informative testing procedure. Sterilisation processes, with different profiles and load amounts, were run in a medium-sized steam steriliser. NCGs and steam condensate volumes were measured every 30 s using the standard method, and NCG% values were calculated at different time points and condensate volumes. NCG% variations associated with environmental temperature and pressure were theoretically estimated. NCG% values and test outcomes showed dependence on the process profile, load, condensate collection timing and volume. Environmental conditions had a non-negligible impact on measurements. Overall, NCG measurement variability impacted standard method reliability to qualify the steriliser and to estimate steam composition in the steriliser chamber. Real-time quantitative monitoring of steam composition during every production process is advocated to improve steam sterilisation efficacy and quality.

Collagen structure derangement is a hallmark of several diseases in different types of tissue. Extraction of quantitative markers of collagen organization from nonlinear microscopy images can help early disease detection, but it can be affected by the presence of image noise. This study introduced and validated a novel methodology for a robust quantification of collagen fiber direction, dispersion, and degree of anisotropy (DA) from collagen images, based on the reinforcement of the gradient structure tensor computation with a mixed noise model. The method was validated on a synthetic image dataset, generated by a vector field-based fiber generator algorithm, assessing its capability to distinguish different fiber organization levels and its robustness against increasing levels of image noise. The method showed an accurate estimation of fiber angle direction with errors < 2 deg for a signal-to-noise ratio (SNR) down to 5, and a slight underestimation of angle variability in the presence of fiber scales smaller than the tensor radius. Local and global DA were able to distinguish different degrees of fiber organization even at high noise level (SNR=5), with small accuracy errors for the local (<0.04) and global (<0.06) DA at realistic patterns. Proof-of-concept application of the method to human cardiac samples suggested its potential in distinguishing different collagen organization levels in real tissues. The method may represent a useful tool for the investigation of collagen structural remodeling in a variety of fibrosis-related pathological conditions. Future studies should address the method tuning to specific tissues, diseases, and clinical problems.

Steam sterilization is widely used to process heat-resistant instruments in hospital settings. The presence of non-condensing gases (NCGs) in the steam may severely impact heat transfer and process efficacy. However, the current practice does not include routine NCG monitoring in the sterilizer chamber. This study evaluates the capability of a novel sensor to detect and quantify NCGs in the sterilizer chamber under different conditions occurring in the field. A commercially available steam sterilizer was equipped with the NCG sensor, and a range of sterilization processes were run. NCGs in the sterilizer chamber were obtained by inadequate vacuum during conditioning, or by introducing controlled air volumes during the conditioning or the exposure phase using different access points. Tests were performed with or without load into the chamber. NCG measurements were analysed by mixed-effects models. The sensor provided reproducible measurements of NCGs resulting from ineffective conditioning (marginal R² = 0.88) or introduced during the conditioning (marginal R² = 0.97) and exposure phase (marginal R² = 0.96), with negligible effects of access points or load amounts. The availability of a quantitative measure of steam composition, added to time and temperature, represents a relevant advancement in real-time monitoring of every sterilization process, toward the full-parametric release of steam sterilized loads.

Venous blood collection systems (VBCSs) are combinations of in-vitro diagnostics and medical devices, usually available as integrated set. However, purchasing and using a combination of devices from different sets is considered by clinical laboratories as an option to achieve specific sampling tasks or reduce costs. This systematic review aimed to retrieve available evidence regarding safety, efficacy, and economic aspects of VBCSs, focusing on differences between integrated and combined systems. The literature review was carried out in PubMed. Cited documents and resources made available by scientific organisations were also screened. Extracted evidence was clustered according to Quality/Efficacy/Performance, Safety, and Costs/Procurement domains and discussed in the current European regulatory framework. Twenty documents published between 2010 and 2021 were included. There was no evidence to suggest equivalence between combined and integrated VBCSs in terms of safety and efficacy. Scientific society’s consensus documents and product standards report that combined VBCS can impact operators’ and patients’ safety. Analytical performances and overall efficacy of combined VBCSs are not guaranteed without whole system validation and verification. EU regulatory framework clearly allocates responsibilities for the validation and verification of an integrated VBCS, but not for combined VBCSs, lacking information about the management of product nonconformities and post-market surveillance. Laboratory validation of combined VBCS demands risk-benefit and cost-benefit analyses, a non-negligible organisational and economic burden, and investment in knowledge acquisition. Implications in terms of laboratory responsibility and legal liability should be part of a comprehensive assessment of safety, efficacy, and cost carried out during device procurement.

Implant therapy is a common treatment option in dentistry and orthopedics, but its application is often associated with an increased risk of microbial contamination of the implant surfaces that cause bone tissue impairment. This study aims to develop two silver-enriched platelet-rich plasma (PRP) multifunctional scaffolds active at the same time in preventing implant-associated infections and stimulating bone regeneration. Commercial silver lactate (L) and newly synthesized silver deoxycholate:β-Cyclodextrin (B), were studied in vitro. Initially, the antimicrobial activity of the two silver soluble forms and the PRP enriched with the two silver forms has been studied on microbial planktonic cells. At the same time, the biocompatibility of silver-enriched PRPs has been assessed by an MTT test on human primary osteoblasts (hOBs). Afterwards, an investigation was conducted to evaluate the activity of selected concentrations and forms of silver-enriched PRPs in inhibiting microbial biofilm formation and stimulating hOB differentiation. PRP-L (0.3 µg/mm²) and PRP-B (0.2 µg/mm²) counteract Staphylococcus aureus, Staphylococcus epidermidis and Candida albicans planktonic cell growth and biofilm formation, preserving hOB viability without interfering with their differentiation capability. Overall, the results obtained suggest that L- and B-enriched PRPs represent a promising preventive strategy against biofilm-related implant infections and demonstrate a new silver formulation that, together with increasing fibrin binding protecting silver in truncated cone-shaped cyclic oligosaccharides, achieved comparable inhibitory results on prokaryotic cells at a lower concentration.

During the COVID‐19 pandemic, the use of polypropylene fleece‐based personal protection equipment (PPE) increased significantly to over ten million tons. Typically, most PPEs are discarded after a single use, to prevent self‐infection of users and spread of infectious agents. However, in order to minimize plastic waste without compromising the protective properties of PPE, it is crucial to explore new reusable or longer‐lived materials. Here, a visible light‐activatable antimicrobial photodynamic dye coating for PPEs is presented. In this context, coating with thiomorpholino‐methylene blue (TMB), derived from methylene blue by introducing two thiomorpholine units, is found to show high antibacterial activity. TMB is integrated into rotary printing suspension, a commercial nitrocellulose‐based printing matrix. The concentration of TMB in adhesive is optimized, and found that 5% TMB is suitable for coating PPE, for reducing the number of Gram‐positive and ‐negative bacteria by 99.99% after 6 h of white light irradiation. Bacterial filtration efficiency and breathability tested according to EN 14683, confirmed that TMB coating does not affect the filter performance. Thus, this antimicrobial photodynamic dye coating technique offers a promising solution for a safer and extended use of PPE, and reduction of plastic waste generated by PPEs.

Objetivo: analisar as características de barreira física e biológica de campos de algodão, que são utilizados como sistema de barreira estéril, após múltiplos usos e processamentos na prática clínica. Método: estudo longitudinal observacional de acompanhamento e de avaliação de tecido 100% algodão que foi utilizado como sistema de barreira estéril em um hospital de médio porte. Amostras foram coletadas antes do uso (após três lavagens) e com três, seis, nove, 12 e 15 meses de uso e avaliadas quanto ao número, à espessura e à integridade dos fios, peso, absorção de água e penetração úmida de micro-organismos. Resultados: após 85 lavagens, o número de fios permaneceu inalterado, porém aumentaram-se as fibras desfiadas e o volume de água absorvido. O teste microbiológico utilizando metodologia padrão alemão obteve resultado negativo; já o de penetração de úmida de micro-organismos não apresentou mudanças significativas ao longo do tempo, embora uma fração das células microbianas tenham passado pelas amostras de dupla camada. Conclusão: as propriedades físicas do tecido 100% algodão, utilizado como sistema de barreira estéril, alteraram com usos/processamentos; entretanto essas não interferiram significativamente nos resultados obtidos pelos testes realizados na barreira microbiológica até 85 lavagens.

Objective: to analyze the physical and biological barrier characteristics of cotton fields used as a sterile barrier system after multiple use and processing cycles in the clinical practice. Method: an observational and longitudinal study to monitor and evaluate 100% cotton fabric used as a sterile barrier system in a medium-sized hospital. Samples were collected before use (after three washes) and at three, six, nine, 12 and 15 months of use and evaluated for the number, thickness and integrity of threads, weight, water absorption and wet penetration by microorganisms. Results: after 85 washes, the number of threads remained unchanged, and the shredded fibers and the water volume absorbed were increased. The microbiological test using the German standard methodology obtained a negative result and wet penetration by microorganisms did not show significant changes over time, although a percentage of the microbial cells passed through the double-layer samples. Conclusion: the physical properties of 100% cotton used as a sterile barrier system changed with use/processing cycles; however, these alterations did not significantly interfere with the results obtained by the tests performed on the microbiological barrier up to 85 washes.