Nanogold-based materials in medicine: from their origins to their future.

The properties of gold-based materials have been explored for centuries in several research fields, including medicine. Multiple published production methods for gold nanoparticles (AuNPs) have shown that the physicochemical and optical properties of AuNPs depend on the production method used. These different AuNP properties have allowed exploration of their usefulness in countless distinct biomedical applications over the last few years. Here we present an extensive overview of the most commonly used AuNP production methods, the resulting distinct properties of the AuNPs and the potential application of these AuNPs in diagnostic and therapeutic approaches in biomedicine

A Step Forward in Breast Cancer Research: Gold Nanoparticles as Photothermal Therapy Enhancers

Gold nanoparticles (AuNPs) have been widely used and characterized for multiple biomedical applications, including the enhancement of photothermal therapy (PTT). AuNPs present a particular plasmon resonance band and are able to convert the absorbed optical radiation into heat, which validates their use in PTT. Several production methods have already been proposed for the synthesis of AuNPs, allowing to optimize the particles' morphology, size and optical properties. However, the production methods commonly used are frequently associated with the use of toxic reagents such as Cetyltrimethylammonium bromide, which presents some concerns for clinical applications. Herein, it is proposed a novel AuNPs' core synthesis method using tetrachloroauric acid and a mixture of reducing agents, later on coated with a combination of hyaluronic and oleic acids. The coating here represents a potential improvement of AuNPs biocompatibility, biodegradability and lifetime, while simultaneously potentiating the attachment towards specific ligands, such as the CD44 receptor, to develop more localized and highly selective tools. The produced functionalized nanoparticles were characterized by Dynamic Light Scattering, Microscopy Techniques and Spectroscopy, showing diameter sizes under 350 nm, polydispersity index smaller than 0.4 and enhanced absorbance in the Near Infrared (NIR, 650 to 900 nm) range. Moreover, the AuNPs safety and efficacy were preliminarily assessed in vitro using breast cancer cell lines. No toxicity was observed by MTT assay, both in breast cancer cell lines, and red blood cells. The irradiation process was proved to be safe; however, when combined with the AuNPs administration, it resulted in a significant reduction of cell viability for some of the breast cell lines tested. Thus, the results highlight the potential of the proposed system for some type of tumors, even though further tests are required to better understand the mechanisms behind the obtained results

The Role of Rosmarinic Acid on the Bioproduction of Gold Nanoparticles as Part of a Photothermal Approach for Breast Cancer Treatment.

Breast cancer is a high-burden malignancy for society, whose impact boosts a continuous search for novel diagnostic and therapeutic tools. Among the recent therapeutic approaches, photothermal therapy (PTT), which causes tumor cell death by hyperthermia after being irradiated with a light source, represents a high-potential strategy. Furthermore, the effectiveness of PTT can be improved by combining near infrared (NIR) irradiation with gold nanoparticles (AuNPs) as photothermal enhancers. Herein, an alternative synthetic method using rosmarinic acid (RA) for synthesizing AuNPs is reported. The RA concentration was varied and its impact on the AuNPs physicochemical and optical features was assessed. Results showed that RA concentration plays an active role on AuNPs features, allowing the optimization of mean size and maximum absorbance peak. Moreover, the synthetic method explored here allowed us to obtain negatively charged AuNPs with sizes favoring the local particle accumulation at tumor site and maximum absorbance peaks within the NIR region. In addition, AuNPs were safe both in vitro and in vivo. In conclusion, the synthesized AuNPs present favorable properties to be applied as part of a PTT system combining AuNPs with a NIR laser for the treatment of breast cancer

Functionalized polyester-based materials as UV curable adhesives

UV curable adhesives offer major advantages in comparison to other polymeric based adhesive systems, such as fast-curing rate and control of the polymerization heat evolution, being ideal for application on damaged tissues. Herein, functionalized polymers were prepared by modifying polycaprolactone diol (PCL) with an isocyanate-functional unsaturated acrylic ester, Laromer® 9000, using two different proportions. These functionalized materials were chemically/physically characterized and, after the addition of a biocompatible photoinitiator (Irgacure® 2959), were crosslinked by UV light irradiation. Such procedure allows the obtention of flexible transparent films. Films’ properties such as swelling, hydrolytic degradation, thermal stability, surface energy and adhesive capacity were evaluated. Furthermore, to assess the applicability of the films in biomedical applications, their haemocompatibility and biocompatibility were determined using human dermal fibroblasts as model.info:eu-repo/semantics/acceptedVersio

O Valor Prognóstico do Ponto Ótimo Cardiorrespiratório após Prova de Esforço Cardiorrespiratória Submáxima na Insuficiência Cardíaca

Introduction: Peak oxygen consumption (pVO2) is a key parameter for assessing the prognosis of heart failure with reduced ejection fraction (HFrEF). However, it is less reliable when the cardiopulmonary exercise test (CPET) is not maximal. Objective: To compare the prognostic power of various exercise parameters in submaximal CPET. Methods: Adult patients with HFrEF undergoing CPET in a tertiary center were prospectively assessed. Submaximal CPET was defined as a respiratory exchange ratio ≤1.10. Patients were followed for one year for the primary endpoint of cardiac death and urgent heart transplantation (HT). Various CPET parameters were analyzed as potential predictors of the combined endpoint and their prognostic power (area under the curve [AUC]) was compared using the Hanley-McNeil test. Results: CPET was performed in 442 HFrEF patients (mean age 56±12 years, 80% male), of whom 290 (66%) had a submaximal CPET. Seventeen patients (6%) reached the primary endpoint. The cardiorespiratory optimal point (COP) had the highest AUC value (0.989, p<0.001), and significantly higher prognostic power than other tested parameters, with pVO2 presenting an AUC of 0.753 (p=0.001). COP ≥36 had significantly lower survival free of HT during follow-up (p<0.001) and presented a sensitivity of 100% and a specificity of 89% for the primary endpoint. Conclusion: COP had the highest prognostic power of all parameters analyzed in a submaximal CPET. This parameter can help stratify HFrEF patients who are physiologically unable to reach a maximal level of exercise.info:eu-repo/semantics/publishedVersio

N-(5-Amino-9H-benzo[a]phenoxazin-9-ylidene)propan-1-aminium chlorides as antifungal agents and NIR fluorescence probes

The search for benzo[a]phenoxazines, Nile Blue derivatives, with high antifungal activity and cell labelling capacity based on our previously published works in this type of compounds, led us to the design of compounds with specific substituents in the polycyclic system. Thus, in the present work, four new benzo[a]phenoxazinium chlorides, possessing at the 5-position amino or (3-aminopropyl) amino groups and at the 9-position propylamino or dipropylamino groups, were synthesized. Another analogue, with (3-aminopropyl) amino group at 5-position, ethyl amino group at 9-position and a methyl group at 10-position of the polycyclic system was also synthesized for comparison in the studies performed. Fundamental photophysics (absorption and fluorescent emission) was carried out in absolute ethanol, water, and other aqueous solutions of different pH values, relevant for the potential biological applications of these compounds. The antiproliferative activity of the synthesized benzo[a]phenoxazinium chlorides was determined using Saccharomyces cerevisiae PYCC 4072 and the microdilution method described for antifungal susceptibility tests in yeast. All compounds revealed antifungal activity, being the most active the one possessing an amino group at 5-position and an aminopropyl group at 9-position. The potential as fluorescent probes were evaluated by fluorescence microscopy, using S. cerevisae as a model system of eukaryotic cells, and it was found that the benzo[a]phenoxazinium chlorides stained the cells with preferential accumulation that seems to appear at the vacuolar membrane and/or the perinuclear membrane of the endoplasmatic reticulum.Thanks are due to Fundação para a Ciência e Tecnologia (FCT) and FEDER (European Fund for Regional Development)-COMPETE-QRENEU for financial support through the research centres CQ/UM (UID/QUI/0686/2019 and UIDB/00686/2020) and CBMA (PEst-OE/BIA/UI4050/2019 and UID/BIA/04050/2020), as well as a PhD grant to J. C. F. (SFRH/BD/133207/2017). The NMR spectrometer Bruker Avance III 400 is part of the National NMR Network (PTNMR) and is partially supported by Infrastructure Project No. 022161 (co-financed by FEDER through COMPETE 2020, POCI and PORL and FCT through PIDDAC)

Gold nanoparticles as a part of a photothermal therapy system.

Introduction Photothermal therapy (PTT) is attracting increased attention for the treatment of superficial localized tumors, relying on the induction of local hyperthermia of tumor cells upon their irradiation with light beams1. PTT efficacy depends, however, on the heat generated and, on the depth reached by the light. Some strategies to improve PTT efficacy includes the use of the near infrared (NIR, 650 to 900 nm) radiation to enhance the penetration depth of the light, combined with gold nanoparticles (AuNPs) to enhance the photothermal effect2. Experimental Methods Core AuNPs were synthesized by a novel method using tetrachloroauric acid and a mixture of reducing agents, and subsequently coated with a combination of hyaluronic and oleic acids, for improving the NPs biocompatibility, biodegradability, and lifetime. This coating also promotes the binding of specific cell receptors of the tumor cells. The particles were physico-chemically characterized, and in vitro and in vivo tests were carried out in breast cancer models to assess their safety and efficacy, when applied alone or combined with NIR irradiation3. Results and Discussion AuNPs presented a predominant spherical morphology with sizes under 350 nm, polydispersity index lower than 0.4 and enhanced absorbance in the NIR. The particles showed no toxicity in vitro and promising efficacy in vivo when administering the NPs in situ and later irradiating them externally. Histopathological analysis of tumors treated with both AuNPs and laser irradiation showed the presence of necrosis in most of the tumors and no effect or practically absence in healthy surrounding cells, which are very encouraging outcomes. Conclusion The results are promising, however, there is still room for improving the system, namely by reducing even more the invasiveness of the treatment through the combined use of aerogels structures. Aerogel’s unique properties4 make them ideal candidates to minimize the exposure of healthy tissues to laser radiation, acting as light and thermal insulators, as well as to incorporate the nanoparticles into their skeletal structure and thus potentiating a topical application of the particles. For these reasons, some exploratory methods were carried to produce and design aerogels structures for PTT applications

New Nile blue derivatives as NIR fluorescent probes and antifungal agents

The synthesis of four new Nile Blue derivatives with hydrogen, propyl and/or aminopropyl groups as substituents of the amines of 5- and 9-positions is described. Photophysical properties were evaluated in acidified ethanol and aqueous solution at physiological pH. Antifungal activity is also studied through the obtention of MIC values.Thanks are due to Fundação para a Ciência e Tecnologia (FCT) and FEDER (European Fund for Regional Development)-COMPETE-QRENEU for financial support through the Chemistry Research Centre of the University of Minho (Ref. UID/QUI/00686/2013 and UID/QUI/0686/2016), CBMA (PEst OE/BIA/UI4050/2014) and a PhD grant to J.C.F. (SFRH/BD/133207/2017). The NMR spectrometer Bruker Avance III 400 is part of the National NMR Network (PTNMR) and are partially supported by Infrastructure Project No 022161 (co-financed by FEDER through COMPETE 2020, POCI and PORL and FCT through PIDDAC)

A chromatographic network for the purification of detergent-solubilized six-transmembrane epithelial antigen of the prostate 1 from Komagataella pastoris mini-bioreactor lysates

Funding Information: The authors acknowledge the support from FEDER funds through the POCI-COMPETE 2020–Operational Programme Competitiveness and Internationalisation in Axis I–Strengthening Research, Technological Development and Innovation (Project POCI-01-0145-FEDER-007491), Jorge Barroca-Ferreira's and Ana M. Gonçalves's individual PhD Fellowships (SFRH/BD/130068/2017 and SFRH/BD/147519/2019, respectively), and Luís A. Passarinha's sabbatical fellowship (SFRH/BSAB/150376/2019) from FCT–Fundação para a Ciência e Tecnologia. This work was also supported by the Health Sciences Research Centre CICS-UBI (UIDB/00709/2020 and UIDP/00709/2020), the Applied Molecular Biosciences Unit UCIBIO (UIDB/04378/2020 and UIDP/04378/2020) and the Associate Laboratory Institute for Health and Bioeconomy–i4HB (project LA/P/0140/2020) which are financed by National Funds from FCT/MCTES. Publisher Copyright: © 2022The Six-Transmembrane Epithelial Antigen of the Prostate 1 (STEAP1) is an integral membrane protein involved in cellular communications, in the stimulation of cell proliferation by increasing Reactive Oxygen Species levels, and in the transmembrane-electron transport and reduction of extracellular metal-ion complexes. The STEAP1 is particularly over-expressed in prostate cancer, in contrast with non-tumoral tissues and vital organs, contributing to tumor progression and aggressiveness. However, the current understanding of STEAP1 lacks experimental data on the respective molecular mechanisms, structural determinants, and chemical modifications. This scenario highlights the relevance of exploring the biosynthesis of STEAP1 and its purification for further bio-interaction and structural characterization studies. In this work, recombinant hexahistidine-tagged human STEAP1 (rhSTEAP1-His6) was expressed in Komagataella pastoris (K. pastoris) mini-bioreactor methanol-induced cultures and successfully solubilized with Nonidet P-40 (NP-40) and n-Decyl-β-D-Maltopyranoside (DM) detergents. The fraction capacity of Phenyl-, Butyl-, and Octyl-Sepharose hydrophobic matrices were evaluated by manipulating the ionic strength of binding and elution steps. Alternatively, immobilized metal affinity chromatography packed with nickel or cobalt were also studied in the isolation of rhSTEAP1-His6 from lysate extracts. Overall, the Phenyl-Sepharose and Nickel-based resins provided the desired selectivity for rhSTEAP1-His6 capture from NP-40 and DM detergent-solubilized K. pastoris extracts, respectively. After a polishing step using the anion-exchanger Q-Sepharose, a highly pure, fully solubilized, and immunoreactive 35 kDa rhSTEAP1-His6 fraction was obtained. Altogether, the established reproducible strategy for the purification of rhSTEAP1-His6 paves the way to gather additional insights on structural, thermal, and environmental stability characterization significantly contributing for the elucidation of the functional role and oncogenic behavior of the STEAP1 in prostate cancer microenvironment.publishersversionpublishe