Evaluation of two-phase sample transport upon ablation of gelatin as a proxy for soft biological matrices using nanosecond laser ablation - inductively coupled plasma - mass spectrometry.

BACKGROUND: Recent papers on LA-ICP-MS have reported that certain elements are transported in particulate form, others in gaseous form and still others in a combination of both upon ablation of C-based materials. These two phases display different transport behaviour characteristics, potentially causing smearing in elemental maps, and could be processed differently in the ICP which raises concerns as to accuracy of quantification and emphasizes the need for matrix-matching of external standards. This work aims at a better understanding of two-phase sample transport by evaluating the peak profile changes observed upon varying parameters such as laser energy density and wavelength. RESULTS: It is demonstrated that upon ablation of gelatin, elements are transported predominantly in particulate phase, but already at low laser energy density, a significant fraction of some elements is transported in the gaseous phase, which is even more expressed at higher energy density. This behaviour is element-specific since the ratio of the signal intensity for the analyte element transported in gas phase to the total signal intensity was 0 % for 23Na, 43 % for 66Zn and as high as 95 % for 13C using a 193 nm laser. The results also suggest an effect of the laser wavelength, as all elements show either the same or higher amount of gas phase formation upon ablating with 213 nm versus 193 nm. It was even established that elements that fully occur in particulate form upon ablation using 193 nm laser radiation are partly converted into gaseous phase when using 213 nm. SIGNIFICANCE: This work provides a thorough investigation of the underexposed phenomenon of two-phase sample transport upon ablation of biological samples upon via LA-ICP-MS. It is shown that for some elements a fraction of the ablated material is converted and transported in the gas phase, which can lead to significant smearing effects. As such, it is important to evaluate element-specific peak profiles on beforehand and, if necessary, adapt instrument settings and slow down data acquisition.

CO2-Driven Nebulization of pH-Sensitive Supramolecular Polymers for Intraperitoneal Hydrogel Formation and the Treatment of Peritoneal Metastasis.

Because peritoneal metastasis (PM) from ovarian cancer is characterized by non-specific symptoms, it is often diagnosed at advanced stages. Pressurized intraperitoneal aerosol chemotherapy (PIPAC) can be considered a promising drug delivery method for unresectable PM. Currently, the efficacy of intraperitoneal (IP) drug delivery is limited by the off-label use of IV chemotherapeutic solutions, which are rapidly cleared from the IP cavity. Hence, this research aimed to improve PM treatment by evaluating a nanoparticle-loaded, pH-switchable supramolecular polymer hydrogel as a controlled release drug delivery system that can be IP nebulized. Moreover, a multidirectional nozzle was developed to allow nebulization of viscous materials such as hydrogels and to reach an even IP gel deposition. We demonstrated that acidification of the nebulized hydrogelator solution by carbon dioxide, used to inflate the IP cavity during laparoscopic surgery, stimulated the in situ gelation, which prolonged the IP hydrogel retention. In vitro experiments indicated that paclitaxel nanocrystals were gradually released from the hydrogel depot formed, which sustained the cytotoxicity of the formulation for 10 days. Finally, after aerosolization of this material in a xenograft model of PM, tumor progression could successfully be delayed, while the overall survival time was significantly increased compared to non-treated animals.

The Efficacy of Nanoparticle Delivery to Hypoxic Solid Tumors by ciRGD Co-Administration Depends on Neuropilin-1 and Neutrophil Levels.

The ability to improve nanoparticle delivery to solid tumors is an actively studied domain, where various mechanisms are looked into. In previous work, the authors have looked into nanoparticle size, tumor vessel normalization, and disintegration, and here it is aimed to continue this work by performing an in-depth mechanistic study on the use of ciRGD peptide co-administration. Using a multiparametric approach, it is observed that ciRGD can improve nanoparticle delivery to the tumor itself, but also to tumor cells specifically better than vessel normalization strategies. The effect depends on the level of tumor perfusion, hypoxia, neutrophil levels, and vessel permeability. This work shows that upon characterizing tumors for these parameters, conditions can be selected that can optimally benefit from ciRGD co-administration as a means to improve NP delivery to solid tumors.

The influence of physiological and lifestyle factors on essential mineral element isotopic compositions in the human body: implications for the design of isotope metallomics research.

In the last 20 years, the application of high-precision isotopic analysis of essential mineral elements (Mg, K, Ca, Fe, Cu, and Zn) to biomedicine (sometimes referred to as isotope metallomics) has revealed that their stable isotopic compositions are altered by the metal dysregulation that is fundamental to the pathogenesis of many cancers and other diseases. Despite many published works showing the diagnostic and prognostic potential of this approach, a number of factors that may influence the stable isotopic composition of these essential mineral elements in healthy individuals remain unstudied. In this perspective article, we summarize the available evidence from trophic level studies, animal models, and ancient and modern humans, relating to physiological and lifestyle factors that appear likely (there is evidence indicating their influence) or unlikely (there is evidence indicating their lack of influence) to require controlling for when investigating variations in essential mineral element isotopic compositions in human subjects. We also discuss factors that require additional data to properly assess. There is evidence that sex, menopausal status, age, diet, vitamin and metal supplementation, genetic variation, and obesity influence the isotopic composition of at least one essential mineral element in the human body. The task of investigating potential influences on essential mineral element isotopic compositions in the human body is sizeable, but presents an exciting research opportunity, with each incremental advance helping to improve the quality of research output in the context of isotope metallomics.

Gold nanoparticle delivery to solid tumors: a multiparametric study on particle size and the tumor microenvironment.

Nanoparticle (NP) delivery to solid tumors remains an actively studied field, where several recent studies have shed new insights into the underlying mechanisms and the still overall poor efficacy. In the present study, Au NPs of different sizes were used as model systems to address this topic, where delivery of the systemically administered NPs to the tumor as a whole or to tumor cells specifically was examined in view of a broad range of tumor-associated parameters. Using non-invasive imaging combined with histology, immunohistochemistry, single-cell spatial RNA expression and image-based single cell cytometry revealed a size-dependent complex interaction of multiple parameters that promoted tumor and tumor-cell specific NP delivery. Interestingly, the data show that most NPs are sequestered by tumor-associated macrophages and cancer-associated fibroblasts, while only few NPs reach the actual tumor cells. While perfusion is important, leaky blood vessels were found not to promote NP delivery, but rather that delivery efficacy correlated with the maturity level of tumor-associated blood vessels. In line with recent studies, we found that the presence of specialized endothelial cells, expressing high levels of CD276 and Plvap promoted both tumor delivery and tumor cell-specific delivery of NPs. This study identifies several parameters that can be used to determine the suitability of NP delivery to the tumor region or to tumor cells specifically, and enables personalized approaches for maximal delivery of nanoformulations to the targeted tumor.

Quantitative mapping of mercury and selenium in mushroom fruit bodies with laser ablation-inductively coupled plasma-mass spectrometry.

This work describes the development of a novel method for quantitative mapping of Hg and Se in mushroom fruit body tissues with laser ablation coupled to inductively coupled plasma-mass spectrometry (LA-ICP-MS). Different parameters of the protocol for preparation of the standards used for quantification via external calibration were assessed, e.g., the dissolution temperature of gelatin standards and the addition of chitosan and L-cysteine as additives to the gelatin-based calibration droplets to better match the sample matrix. While chitosan was not suited for this purpose, the presence of L-cysteine considerably improved the figures of merit of the calibration, leading to limits of detection of 0.006 and 0.3 µg g-1 for Hg and Se, respectively, at a pixel size of 20 × 20 µm. Further, an in-house reference material, ideally suited for the validation of the method for application to mushroom samples, was successfully prepared from a paste of Boletus edulis. The newly developed method was used to investigate the distribution of Hg and Se in tissue sections of five porcini mushroom individuals of three different species (Boletus edulis, Boletus aereus, and Boletus pinophilus) and one sample of a parasol mushroom (Macrolepiota procera). For one sample, additional areas were ablated at higher spatial resolution, with a laser spot size down to 5 µm, which allows a detailed investigation of the spatial distribution of Hg and Se in mushrooms.

What can we learn from studying plastic debris in the Sea Scheldt estuary?

The Sea Scheldt estuary has been suggested to be a significant pathway for transfer of plastic debris to the North Sea. We have studied 12,801 plastic items that were collected in the Sea Scheldt estuary (Belgium) during 3 sampling campaigns (in spring, summer, and autumn) using a technique called anchor netting. The investigation results indicated that the abundance of plastic debris in the Scheldt River was on average 1.6 × 10-3 items per m3 with an average weight of 0.38 × 10-3 g per m3. Foils were the most abundant form, accounting for >88 % of the samples, followed by fragments for 11 % of the samples and filaments, making up for <1 % of the plastic debris. FTIR spectroscopy of 7 % of the total number of plastic debris items collected in the Sea Scheldt estuary (n = 883) revealed that polypropylene (PP), polyethylene (PE), and polystyrene (PS) originating from disposable packaging materials were the most abundant types of polymers. A limited number of plastic debris items (n = 100) were selected for non-destructive screening of their mineral element composition using micro-X-ray fluorescence spectrometry (µXRF). The corresponding results revealed that S, Ca, Si, P, Al, and Fe were the predominant mineral elements. These elements originate from flame retardants, mineral fillers, and commonly used catalysts for plastic production. Finally, machine learning algorithms were deployed to test a new concept for forensic identification of the different plastic entities based on the most important elements present using a limited subset of PP (n = 36) and PE (n = 35) plastic entities.

Photothermal nanofibres enable safe engineering of therapeutic cells.

Nanoparticle-sensitized photoporation is an upcoming approach for the intracellular delivery of biologics, combining high efficiency and throughput with excellent cell viability. However, as it relies on close contact between nanoparticles and cells, its translation towards clinical applications is hampered by safety and regulatory concerns. Here we show that light-sensitive iron oxide nanoparticles embedded in biocompatible electrospun nanofibres induce membrane permeabilization by photothermal effects without direct cellular contact with the nanoparticles. The photothermal nanofibres have been successfully used to deliver effector molecules, including CRISPR-Cas9 ribonucleoprotein complexes and short interfering RNA, to adherent and suspension cells, including embryonic stem cells and hard-to-transfect T cells, without affecting cell proliferation or phenotype. In vivo experiments furthermore demonstrated successful tumour regression in mice treated with chimeric antibody receptor T cells in which the expression of programmed cell death protein 1 (PD1) is downregulated after nanofibre photoporation with short interfering RNA to PD1. In conclusion, cell membrane permeabilization with photothermal nanofibres is a promising concept towards the safe and more efficient production of engineered cells for therapeutic applications, including stem cell or adoptive T cell therapy.

Single-event tandem ICP-mass spectrometry for the quantification of chemotherapeutic drug-derived Pt and endogenous elements in individual human cells.

Single cell - tandem ICP-mass spectrometry (SC-ICP-MS/MS) was used for the determination of the absolute amount of Pt (coming from exposure to various concentration levels of cisplatin as a chemotherapeutic drug) and five endogenous elements (P, S, Fe, Cu and Zn) in individual human cells of three different types - Raji, Jurkat and Y79. Optimum conditions were obtained by using a sample introduction unit transporting cell suspension containing approx. 5 × 104 cells per mL at a flow rate of 10 µL min-1 to a nebulizer with narrow internal diameter (250 µm i.d.), mounted onto a total consumption spray chamber. Interference-free conditions were obtained in tandem MS mode (i) for P and S by pressurizing the collision/reaction cell (CRC) with O2 and monitoring the PO+ and SO + reaction product ions and (ii) for Fe by pressurizing the CRC with NH3 and monitoring the Fe(NH3)2+ reaction product ion. The quantification approach was validated by comparison of the absolute amounts of the target elements (in fg per cell) as obtained using SC-ICP-MS/MS with those obtained after acid digestion of approx. 2 × 106 cells and subsequent solution ICP-MS/MS analysis ("bulk" analysis). A higher Pt cell content was observed upon increasing the concentration of the cisplatin solution the cells were exposed to during 24 h. The Pt mass per cell (fg) increased linearly as a function of the cisplatin concentration, but a higher Pt uptake was found in the case of Jurkat cells compared to the other cell types. A cell viability assay showed a lack of chemosensitivity to cisplatin below 200 µM for the Raji and Y79 cell line, but an IC50 value of 11.1 ± 1.3 µM for Jurkat cells. This difference in chemo-responsiveness between the different cell types supported the difference in Pt uptake as indicated via SC-ICP-MS analysis. The increasing level of Pt did not have a marked effect on the contents of the endogenous elements monitored in Raji and Y79 cells, but a decrease in the P and S cell content upon increasing cisplatin treatment was observed for Jurkat cells. This can most likely be attributed to stress induced by the chemotherapeutic treatment in cells showing chemosensitivity towards cisplatin. The results also indicate differences in the absolute amount of endogenous element per cell between different cell types, suggesting the potential of SC-ICP-MS as a "metallo-fingerprinting" tool.

Bubble Forming Films for Spatial Selective Cell Killing.

Photodynamic and photothermal cell killing at the surface of tissues finds applications in medicine. However, a lack of control over heat dissipation following a treatment with light might damage surrounding tissues. A new strategy to kill cells at the surface of tissues is reported. Polymeric films are designed in which iron oxide nanoparticles are embedded as photosensitizers. Irradiation of the films with pulsed laser light generates water vapor bubbles at the surface of the films. It is found that "bubble-films" can kill cells in close proximity to the films due to mechanical forces which arise when the bubbles collapse. Local irradiation of bubble-films allows for spatial selective single cell killing. As nanosurgery becomes attractive in ophthalmology to remove superficial tumors, bubble-films are applied on the cornea and it is found that irradiation of the bubble-films allows spatial and selective killing of corneal cells. As i) the photosensitizer is embedded in the films, which reduces its uptake by cells and spreading into tissues and ii) the bubble-films can be removed from the tissue after laser treatment, while iii) a low laser fluence is sufficient to generate vapor bubbles, it is foreseen that bubble-films might become promising for safe resection of superficial tumors.

Distinct EH domains of the endocytic TPLATE complex confer lipid and protein binding.

Clathrin-mediated endocytosis (CME) is the gatekeeper of the plasma membrane. In contrast to animals and yeasts, CME in plants depends on the TPLATE complex (TPC), an evolutionary ancient adaptor complex. However, the mechanistic contribution of the individual TPC subunits to plant CME remains elusive. In this study, we used a multidisciplinary approach to elucidate the structural and functional roles of the evolutionary conserved N-terminal Eps15 homology (EH) domains of the TPC subunit AtEH1/Pan1. By integrating high-resolution structural information obtained by X-ray crystallography and NMR spectroscopy with all-atom molecular dynamics simulations, we provide structural insight into the function of both EH domains. Both domains bind phosphatidic acid with a different strength, and only the second domain binds phosphatidylinositol 4,5-bisphosphate. Unbiased peptidome profiling by mass-spectrometry revealed that the first EH domain preferentially interacts with the double N-terminal NPF motif of a previously unidentified TPC interactor, the integral membrane protein Secretory Carrier Membrane Protein 5 (SCAMP5). Furthermore, we show that AtEH/Pan1 proteins control the internalization of SCAMP5 via this double NPF peptide interaction motif. Collectively, our structural and functional studies reveal distinct but complementary roles of the EH domains of AtEH/Pan1 in plant CME and connect the internalization of SCAMP5 to the TPLATE complex.

Cytosolic delivery of gadolinium via photoporation enables improved in vivo magnetic resonance imaging of cancer cells.

Longitudinal in vivo monitoring of transplanted cells is crucial to perform cancer research or to assess the treatment outcome of cell-based therapies. While several bio-imaging techniques can be used, magnetic resonance imaging (MRI) clearly stands out in terms of high spatial resolution and excellent soft-tissue contrast. However, MRI suffers from low sensitivity, requiring cells to be labeled with high concentrations of contrast agents. An interesting option is to label cells with clinically approved gadolinium chelates which generate a hyperintense MR signal. However, spontaneous uptake of the label via pinocytosis results in its endosomal sequestration, leading to quenching of the T1-weighted relaxation. To avoid this quenching effect, delivery of gadolinium chelates directly into the cytosol via electroporation or hypotonic cell swelling have been proposed. However, these methods are also accompanied by several drawbacks such as a high cytotoxicity, and changes in gene expression and phenotype. Here, we demonstrate that nanoparticle-sensitized laser induced photoporation forms an attractive alternative to efficiently deliver the contrast agent gadobutrol into the cytosol of both HeLa and SK-OV-3 IP1 cells. After intracellular delivery by photoporation the quenching effect is clearly avoided, leading to a strong increase in the hyperintense T1-weighted MR signal. Moreover, when compared to nucleofection as a state-of-the-art electroporation platform, photoporation has much less impact on cell viability, which is extremely important for reliable cell tracking studies. Additional experiments confirm that photoporation does not induce any change in the long-term viability or the migratory capacity of the cells. Finally, we show that gadolinium 'labeled' SK-OV-3 IP1 cells can be imaged in vivo by MRI with high soft-tissue contrast and spatial resolution, revealing indications of potential tumor invasion or angiogenesis.

Inter-comparison of stable iron, copper and zinc isotopic compositions in six reference materials of biological origin.

There is a lack of certified reference materials with an organic matrix for which metal isotope ratios have been certified. Here, we have determined the iron, copper and zinc stable isotopic compositions for six reference materials of biological origin with diverse matrices, i.e. BCR-380R (whole milk), BCR-383 (beans), ERM-CE464 (tuna fish), SRM-1577c (bovine liver), DORM-4 (fish protein) and TORT-3 (lobster hepatopancreas) in three different labs. The concentrations for six major and sixteen trace elements, spanning almost four orders of magnitude, were also measured and the results obtained show an excellent agreement with certified values, demonstrating that the dissolution step was quantitative for all the standards. By taking literature data into account, 39 possible pair-wise comparisons of mean iron, copper and zinc isotopic values (δ values) could be made. Results of Tukey multiple comparisons of means yielded 11 significantly different pairs. Most of these differences are of the same order of magnitude as the estimated mean expanded uncertainties (U, k = 2) (±0.10‰, ±0.05‰, and ±0.05‰ for the δ56Fe, δ65Cu and δ66Zn values, respectively). The present inter-comparison study finally proposes nineteen new preferred values for the Cu, Zn and Fe isotopic compositions of six reference materials of biological origin.

Quantification of uranium, plutonium, neodymium and gadolinium for the characterization of spent nuclear fuel using isotope dilution HPIC-SF-ICP-MS.

A method was developed for the determination of the nuclide-specific concentrations of U, Pu, Nd and Gd in two types of spent nuclear fuel (UOx and Gd-enriched). High-performance ion chromatography (HPIC) was used to separate the target elements from one another while sector-field inductively coupled plasma-mass spectrometry (SF-ICP-MS) was used for their determination relying on isotope dilution for calibration. In order to obtain the best possible precision for these isotope ratios extracted from the transient HPIC-SF-ICP-MS signals, the SF-ICP-MS data acquisition parameters were optimized and the most suitable method for calculating the isotope ratios from the transient signals was identified. The point-by-point (PbP), linear regression slope (LRS) and peak area integration (PAI) approaches were compared in the latter context. It was found that data acquisition in the flat centre of the spectral flat top peak using a mass window of 25%, a dwell time of 10 ms and 20 samples per peak, while using PAI for isotope ratio calculation, gave the best precision on the isotope ratios extracted from the HPIC-SF-ICP-MS transient signals. These parameters were used in the determination of the nuclide-specific mass fractions of Pu, Nd and Gd in two types of spent nuclear fuel using isotope dilution HPIC-SF-ICP-MS. For U, which was present at a higher concentration, the element fraction was collected and analyzed off-line after dilution. For the other target elements, an online approach was used. An uncertainty budget estimation was made using the bottom-up approach for the resulting mass fractions, and the accuracy and precision obtained when using isotope dilution HPIC-SF-ICP-MS were compared with those obtained with the routinely used techniques, isotope dilution TIMS & alpha spectrometry (an ISO 17025 accredited method).

Cu and Zn isotope ratio variations in plasma for survival prediction in hematological malignancy cases.

We have examined potential changes in the isotopic compositions of Fe, Cu and Zn (using multi-collector inductively coupled plasma-mass spectrometry) and the corresponding concentrations (using inductively coupled plasma-atomic emission spectrometry) in plasma from hematological malignancy (HM) patients and assessed their prognostic capability. Together with clinical laboratory test values, data were examined in view of a 5-years survival prediction. Plasma Cu and Zn isotope ratios and their concentrations were significantly different in HM patients compared to matched controls (P < 0.05). Both δ65Cu and δ66Zn values showed significant mortality hazard ratios (HRs) in HM. The group of patients with decreased δ65Cu and increased δ66Zn values showed significantly poorer survival from the early phase (HR 3.9; P = 0.001), forming a unique cohort not identified based on laboratory test values. Well-known prognostic factors for HM, such as the creatinine level, and anemia-related values were highly correlated with the δ66Zn value (P < 0.05). Time-dependent ROC curves based on the δ65Cu or δ66Zn value were similar to that based on the creatinine concentration (a well-known prognostic factor in HM), indicating that δ65Cu or δ66Zn values are useful for prognosis of HM. Variations in stable isotope ratios of essential mineral elements have thus been shown to reflect alterations in their homeostasis due to physiological changes in malignancies with higher sensitivity than concentrations do.

Feasibility of Mechanical Extrusion to Coat Nanoparticles with Extracellular Vesicle Membranes.

Biomimetic functionalization to confer stealth and targeting properties to nanoparticles is a field of intense study. Extracellular vesicles (EV), sub-micron delivery vehicles for intercellular communication, have unique characteristics for drug delivery. We investigated the top-down functionalization of gold nanoparticles with extracellular vesicle membranes, including both lipids and associated membrane proteins, through mechanical extrusion. EV surface-exposed membrane proteins were confirmed to help avoid unwanted elimination by macrophages, while improving autologous uptake. EV membrane morphology, protein composition and orientation were found to be unaffected by mechanical extrusion. We implemented complementary EV characterization methods, including transmission- and immune-electron microscopy, and nanoparticle tracking analysis, to verify membrane coating, size and zeta potential of the EV membrane-cloaked nanoparticles. While successful EV membrane coating of the gold nanoparticles resulted in lower macrophage uptake, low yield was found to be a significant downside of the extrusion approach. Our data incentivize more research to leverage EV membrane biomimicking as a unique drug delivery approach in the near future.

Method development for on-line species-specific sulfur isotopic analysis by means of capillary electrophoresis/multicollector ICP-mass spectrometry.

In this work, a method for species-specific isotopic analysis of sulfur via capillary electrophoresis hyphenated on-line with multicollector ICP-MS (CE/MC-ICP-MS) was developed. Correction for the mass bias caused by instrumental mass discrimination was realized via external correction with multiple-injection sample-standard bracketing. By comparing the isotope ratio measurement results obtained using the newly developed on-line CE/MC-ICP-MS method with those obtained via traditional MC-ICP-MS measurement after analyte/matrix separation by anion exchange chromatography for isotopic reference materials and an in-house bracketing standard, the most suitable data evaluation method could be identified. The repeatability for the sulfate-δ34S value (calculated from 18 measurements of a standard conducted over seven measurement sessions) was 0.57‰ (2SD) and thereby only twice that obtained with off-line measurements (0.30‰, n = 68). As a proof of concept for analysis of samples with a real matrix, the determination of the sulfur isotopic composition of naturally present sulfate was performed for different river systems. The CE/MC-ICP-MS results thus obtained agreed with the corresponding off-line MC-ICP-MS results within the 2SD ranges, and the repeatability of consecutive δ34S measurements (n = 3) was between 0.3‰ and 1.3‰ (2SD). Finally, the isotopic analysis of two different S-species in a river water sample spiked with 2-pyridinesulfonic acid (PSA) was also accomplished. Graphical abstract The CE/MC-ICP-MS method developed allows for species-specific S isotopic analysis in samples containing multiple species. Mass bias is corrected for by multiple-injection sample-standard bracketing, while the repeatability (2SD) of the resulting 34δ-values is <1‰.

Synergy between Intraperitoneal Aerosolization (PIPAC) and Cancer Nanomedicine: Cisplatin-Loaded Polyarginine-Hyaluronic Acid Nanocarriers Efficiently Eradicate Peritoneal Metastasis of Advanced Human Ovarian Cancer.

Intra-abdominal dissemination of peritoneal nodules, a condition known as peritoneal carcinomatosis (PC), is typically diagnosed in ovarian cancer patients at the advanced stages. The current treatment of PC consists of perioperative systemic chemotherapy and cytoreductive surgery, followed by intra-abdominal flushing with solutions of chemotherapeutics such as cisplatin and oxaliplatin. In this study, we developed cisplatin-loaded polyarginine-hyaluronic acid nanoscale particles (Cis-pARG-HA NPs) with high colloidal stability, marked drug loading efficiency, unimpaired biological activity, and tumor-targeting ability. Injected Cis-pARG-HA NPs showed enhanced antitumor activity in a rat model of PC, compared to injection of the free cisplatin drug. The activity of Cis-pARG-HA NPs could even be further improved when administered by an intra-abdominal aerosol therapy, referred to as pressurized intraperitoneal aerosol chemotherapy (PIPAC). PIPAC is hypothesized to ensure a more homogeneous drug distribution together with a deeper drug penetration into peritoneal tumor nodules within the abdominal cavity. Using fluorescent pARG-HA NPs, this enhanced nanoparticle deposit on tumors could indeed be observed in regions opposite the aerosolization nozzle. Therefore, this study demonstrates that nanoparticles carrying chemotherapeutics can be synergistically combined with the PIPAC technique for IP therapy of disseminated advanced ovarian tumors, while this synergistic effect was not observed for the administration of free cisplatin.

Enhancement of Biomimetic Enzymatic Mineralization of Gellan Gum Polysaccharide Hydrogels by Plant-Derived Gallotannins.

Mineralization of hydrogel biomaterials with calcium phosphate (CaP) is considered advantageous for bone regeneration. Mineralization can be both induced by the enzyme alkaline phosphatase (ALP) and promoted by calcium-binding biomolecules, such as plant-derived polyphenols. In this study, ALP-loaded gellan gum (GG) hydrogels were enriched with gallotannins, a subclass of polyphenols. Five preparations were compared, namely three tannic acids of differing molecular weight (MW), pentagalloyl glucose (PGG), and a gallotannin-rich extract from mango kernel (Mangifera indica L.). Certain gallotannin preparations promoted mineralization to a greater degree than others. The various gallotannin preparations bound differently to ALP and influenced the size of aggregates of ALP, which may be related to ability to promote mineralization. Human osteoblast-like Saos-2 cells grew in eluate from mineralized hydrogels. Gallotannin incorporation impeded cell growth on hydrogels and did not impart antibacterial activity. In conclusion, gallotannin incorporation aided mineralization but reduced cytocompatibility.