Uptake and toxicity of polystyrene micro/nanoplastics in gastric cells: Effects of particle size and surface functionalization

Toxicity of micro or nanoplastics (MP/NP) in aquatic life is well-documented, however, information about the consequences of exposure to these particles in terrestrial species is scarce. This study was used to evaluate the uptake and/or toxicity of polystyrene MP/NP in human gastric cells, comparing doses, particle sizes (50, 100, 200, 500, 1000 or 5000 nm) and surface functionalization (aminated, carboxylated or non-functionalized). In general, the uptake of 50 nm particles was significantly higher than 1000 nm particles. Among the 50 nm particles, the aminated particles were more avidly taken up by the cells and were cytotoxic at a lower concentration (≥ 7.5 μg/mL) compared to same sized carboxylated or non-functionalized particles (≥ 50 μg/mL). High toxicity of 50 nm aminated particles corresponded well with significantly high rates of apoptosis-necrosis induced by these particles in 4 h (29.2% of total cells) compared to all other particles (≤ 16.8%). The trend of apoptosis-necrosis induction by aminated particles in 4 h was 50 > 5000 > 1000 > 500 > 200 > 100 nm. The 50 nm carboxylated or non-functionalized particles also induced higher levels of apoptosis-necrosis in the cells compared to 100, 1000 and 5000 nm particles with same surface functionalization but longer exposure (24 h) to 50 nm carboxylated or non-functionalized particles significantly (p<0.0001) increased apoptosis-necrosis in the cells. The study demonstrated that the toxicity of MP/NP to gastric cells was dependent on particle size, dose surface functionalization and exposure period.

Dendrimer evolution timeline: Ground-breaking progress in cancer treatment

Dendrimers holds potential in abating restrictions of other available treatments through the development of functionalized particles for targeted treatment. By developing functionalized particles for targeted treatment, dendrimers have the ability to reduce the limitations of other available therapies. Dendrimers have many advantages over other nanoparticles, making them perfect candidates for more efficient and targeted drug delivery. Dendrimers have the ability to deliver vast quantities of drugs to particular locations. They can also be used to monitor the progress of the procedure, giving them a theranostic capability that has never been seen before. Dendrimers show their potential applicability for effective cancer treatment for the near future. These article highlights the evolution timeline of dendrimers and various related aspects of the past four decades. These also involve the basic structure and information of dendrimers along with the current and future perspective. As a result, it is important to study dendrimers in order to keep up with recent developments.

Effect of different silica coatings on the toxicity of upconversion nanoparticles on RAW 264.7 macrophage cells

Upconversion nanoparticles (UCNPs), consisting of NaYF4 doped with 18% Yb and 2% Er, were coated with microporous silica shells with thickness values of 7 ± 2 and 21 ± 3 nm. Subsequently, the negatively charged particles were functionalized with N-(6-aminohexyl)-3-aminopropyltrimethoxysilane (AHAPS), which provide a positive charge to the nanoparticle surface. Inductively coupled plasma optical emission spectrometry (ICP-OES) measurements revealed that, over the course of 24h, particles with thicker shells release fewer lanthanide ions than particles with thinner shells. However, even a 21 ± 3 nm thick silica layer does not entirely block the disintegration process of the UCNPs. 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assays and cell cytometry measurements performed on macrophages (RAW 264.7 cells) indicate that cells treated with amino-functionalized particles with a thicker silica shell have a higher viability than those incubated with UCNPs with a thinner silica shell, even if more particles with a thicker shell are taken up. This effect is less significant for negatively charged particles. Cell cycle analyses with amino-functionalized particles also confirm that thicker silica shells reduce cytotoxicity. Thus, growing silica shells to a sufficient thickness is a simple approach to minimize the cytotoxicity of UCNPs.

Environmental exposure enhances the internalization of microplastic particles into cells

Microplastic particles ubiquitously found in the environment are ingested by a huge variety of organisms. Subsequently, microplastic particles can translocate from the gastrointestinal tract into the tissues likely by cellular internalization. The reason for cellular internalization is unknown, since this has only been shown for specifically surface-functionalized particles. We show that environmentally exposed microplastic particles were internalized significantly more often than pristine microplastic particles into macrophages. We identified biomolecules forming an eco-corona on the surface of microplastic particles, suggesting that environmental exposure promotes the cellular internalization of microplastics. Our findings further indicate that cellular internalization is a key route by which microplastic particles translocate into tissues, where they may cause toxicological effects that have implications for the environment and human health.

Effect of Different Silica Coatings on the Toxicity of upconversion nanoparticles on RAW 264.7 macrophage cells

Upconversion nanoparticles (UCNP) consisting of NaYF₄ doped with 18% Yb and 2% Er were coated with microporous silica shells of 7±2 nm and 21±3 nm thickness. Subsequently, the initially negatively charged particles were optionally functionalized with N-(6-aminohexyl)-aminopropyltrimethoxysilane (AHAPS), providing a positive charge onto the nanoparticle surface. Inductively coupled plasma optical emission spectrometry (ICP-OES) measurements revealed that the particles with the thicker shells release fewer lanthanide ions in 24 h than particles with a thinner shell but that even a 21±3 nm thick silica layer does not entirely block the disintegration process of the UCNP. MTT tests and cell cytometry measurements with macrophages (RAW 264.7 cells) indicate that the cells treated with amino-functionalized particles with a thicker silica shell have higher viability than those incubated with UCNP with a thinner silica shell even if more particles with a thicker shell are taken up. This effect is less significant for negatively charged particles. A cell cycle analysis with amino-functionalized particles also confirms that a thicker silica shell reduces the cytotoxicity. Thus, growing silica shells of sufficient thickness is a simple approach to minimize the cytotoxicity of UCNP.

Millimetric particles functionalized with biocide to improve biofouling control in RO system

&lt;p&gt;Biofouling is responsible for more than 45% of all membrane fouling associated problems and is highly relevant for the performance of Reverse Osmosis systems (RO). Biofouling has a tremendous negative impact on the quality and quantity of permeate water and is responsible for high operational and maintenance costs associated with such systems. Current strategies targeting biofilm control on membrane systems often include the overuse of disinfectants which most of the time fail to effectively prevent biofouling build-up, can lead to the formation of dangerous disinfection by-products and represents high amounts of discharged biocides.&lt;/p&gt; &lt;p&gt;&amp;#160;&lt;/p&gt; &lt;p&gt;The present work aims to study how millimetric (1-3 mm length) alumina particles, functionalized with a well-known quaternary ammonium compound biocide (benzalkonium chloride) and immobilized into a Particle Biocide Bed Reactor can effectively contribute to mitigate biofilm formation in membrane systems. For that, the functionalized particles were chemically characterized, and their antimicrobial activity was assessed in batch and recirculation assays and quantified in terms of Culturability and Propidium Iodide (PI) uptake. Special attention has been given to biocides&amp;#8217;s (free and immobilized) mechanism of action and potential biocide release was evaluated by High Performance Liquid Chromatography (HPLC) measurements.&lt;/p&gt; &lt;p&gt;&amp;#160;&lt;/p&gt; &lt;p&gt;The preliminary experiments indicate that the immobilized biocide (equivalent biocide concentration of 3 g/L) has an antimicrobial activity against Pseudomonas fluorescens (initial concentration 10&lt;sup&gt;8&lt;/sup&gt; CFU/mL) by reducing 4 logs after 30 min and 8 logs after 1 h. On the other hand, the control assays (functionalized particles in water with no bacteria), also shows a biocide release between 0.8 and 1% to the bulk water after 30 min, both in batch and in the Particle Bed Reactor with recirculation experiments. No significant biocide increase is observed in the bulk liquid studies for two weeks.&amp;#160;Nonetheless, some changes in the functionalization approach are being made to improve the biocidal anchoring to the particle.&lt;/p&gt;

Purification of sialoglycoproteins from bovine milk using serotonin-functionalized magnetic particles and their application against influenza A virus

Serotonin-functionalized particles were used to isolate sialoglycoproteins, which have the ability to inhibit the attachment of IAV mimics to MDCK cells.