Poly Methyl Methacrylate Nanoparticles Research Articles

Facile way of preparing PMMA@TiO2@SiO2 (P@T@S) composite microspheres with high haze and light transmittance for diffusion film

AbstractIn recent years, optical diffusion film materials with high transmittance and high haze have been widely reported, while there is relatively rare research on their functionalization and practical application especially in real scenario. In this work, optical diffusion films using polymethyl methacrylate (PMMA)@TiO2@SiO2 (P@T@S) composite microspheres were fabricated, which exhibited sufficiently high light transmittance and haze. The binding mode of PMMA microspheres and nanoparticles suggested that PMMA microspheres with a positive surface potential combined with nanoparticles with a negative surface potential through electrostatic attraction to achieve mutual binding. The prepared P@T@S composite microspheres showed better heat and swelling resistance than those of PMMA microspheres. The P@T@S diffusion film, whose excellent light diffusion effect was clearly demonstrated, exhibited the best optical performance among all optical diffusion films prepared. After passing through the P@T@S diffusion film, the laser light was not only uniform but also bright. The findings from this work can provide some insight into further research on optical diffusion films applied in optoelectronic device areas.

Conversion of PET Bottle Waste into a Terephthalic Acid-Based Metal-Organic Framework for Removing Plastic Nanoparticles from Water

Micro- and nanoparticles of plastic waste are considered emerging pollutants with significant environmental and health impacts at high concentrations or prolonged exposure time. Here we report the synthesis and characterization of a known metal-organic framework (MOF) using terephthalic acid (TPA) recovered from the hydrolysis of polyethylene terephthalate (PET) bottle waste. This approach adds value to the existing large amounts of bottle waste in the environment. Fully characterized zinc-TPA MOF (MOF-5) was used for the extraction and removal of engineered polyvinyl chloride (PVC) and polymethylmethacrylate (PMMA) nanoparticles from water with a high efficiency of 97% and 95%, respectively. Kinetic and isotherm models for the adsorption of polymer nanoparticles (PNPs) on the MOF surface were investigated to understand the mechanism. The Qmax for PVC and PMMA NPs were recorded as 56.65 mg/g and 33.32 mg/g, respectively. MOF-5 was characterized before and after adsorption of PNPs on the surface of MOF-5 using a range of techniques. After adsorption, the MOF-5 was successfully regenerated and reused for the adsorption and removal of PNPs, showing consistent results for five adsorption cycles with a removal rate of 83–85%. MOF-5 was characterized before and after adsorption of PNPs on the surface using a range of techniques. The MOF-5 with PNPs on the surface was successfully regenerated and reused for the adsorption and removal of polymer nanoparticles, showing consistent results for five extraction cycles. As a proof of concept, MOF-5 was also used to remove plastic particles from commercially available body scrub gel solutions. Such methods and materials are needed to mitigate the health hazards caused by emerging micro- and nanoplastic pollutants in the environment.

Encapsulating carbon dots in polymethyl methacrylate nanoparticles toward improved solid-state fluorescence quantum yield

In this paper, we prepare carbon dots (CDs) through hydrothermal method, and then the CDs are encapsulated in polymethyl methacrylate (PMMA) nanoparticles through the suspension polymerization of MMA nanodroplets, obtaining a CD/PMMA nanocomposite with a CD concentration of 0.3 wt%. The CDs of the nanocomposite are confined in the PMMA nanoparticles, so there is no excessive resonance energy transfer or direct π-π interaction among the CDs in different nanoparticles, weakening the aggregation caused quenching compared with conventional CD/PMMA composite fabricated by directly blending the CDs with bulk PMMA. Consequently, the quantum yield (QY) of this CD/PMMA nanocomposite is higher than that of the conventional CD/PMMA composite, and even very close to that of the dilute CD solution. This study may provide a universal method to prepare CD/polymer solid-state fluorescent materials with higher QYs compared with conventional CD/polymer composites prepared through direct blending CDs with bulk polymers.

Enhancing energy transport in Homann stagnation-point flow over a spiraling disk with ternary hybrid nanofluids

The incorporation of nanoparticles is highly desirable due to their capability to enhance thermal conductivity, which promotes efficient heat dissipation, enhances the performance and reliability of heat-generating/absorption systems. This study investigates the effects of three types of nanoparticles, magnetic field, stretching and rotation of disk on the Homann stagnation point flow. The gold, polystyrene, and polymethylmethacrylate nanoparticles are drenched in ethanol to make a ternary hybrid nanofluid. The governing equations are transformed via similarity transformations, and the resulting system is solved numerically by using the finite difference method. The effects of the nanoparticle's concentration, stretching-rotation of surface, and magnetic field on the velocity, temperature, skin friction, and Nusselt number are analyzed. The mechanism contributes to augment the thermal conductivity of the fluid, resulting in an elevation in temperature and a reduction in velocity. Stretching of the surface promotes the acceleration of fluid particles, leading to higher velocities. On the other hand, the decline in temperature is due to the stretching-induced expansion of the fluid, which reduces the thermal energy. The study provides valuable insights into the complex interactions between nanoparticles, stretching, rotation, and magnetic field on the flow properties and may have practical implications in the design and optimization of nanofluid-based systems for various applications.

Poly(Methylqinjgtebie Methacrylate) Nanoparticles-Based HIF-1α Carrier Reduces Epithelial Cell Activation and Adhesion Molecule Expression in Atopic Dermatitis

Atopic dermatitis (AD) is a skin disease. This study established a mouse AD model to investigate the impact of PMMA (Poly(methyl methacrylate)) nanoparticles (PMMANPs) on epithelial cells. Nice (n = 30) receiving no intervention were taken as a healthy group, while the other animals (n = 30) were placed in the model group and sensitized with 2,4-Dinitrochlorobenzene (DNCB) acetone solution to establish the AD model. Skin epithelial cells on the backs of mice were assigned into blank control group, negative control group, PMMA group, Hypoxia-Inducible Factor (HIF)-1α group, and PMMA + HIF-1α group, followed by analysis of epithelial cell density by toluidine blue staining, HIF-1α, ICAM-1 (Intercellular Adhesion Molecule 1) and VCAM-1 (Vascular cell adhesion molecule-1) expressions. The back skin of mice in the model group appeared with edema, erythema, and desquamation, with increased number of scratches and pathological changes such as skin keratinization, inflammatory cell infiltration, and epidermal thickening, indicating successful establishment of the AD model. In comparison, the epithelial cell density of the PMMA group, HIF-1α group, and PMMA+HIF-1α group (10.08±0.32, 10.50±0.34, 7.52±0.28) decreased significantly (P <0.05), with lowest density in the PMMA+HIF-1α group. Importantly, treatment with HIF-1α, PMMANPs, and HIF-1α-loaded PMMANPs greatly elevated HIF-1α levels (3.25±0.08, 3.69±0.07, 4.46±0.10) while decreased ICAM-1 and VCAM-1 levels (794.02±56.27, 788.36±49.38, 744.64±36.40). Furthermore, combined treatment obtained highest HIF-1α expression and lowest ICAM-1 and VCAM-1 level (P <0.05) expressions. Collectively, the PMMANPs carrying HIF-1α VCAM-1 exerted protective role in the recovery of AD, and these findings suggest that, the HIF-1α can be used as a target gene for AD treatment.

Synthesis of ferrofluid DAA-Glu COF@Aminated alginate/Psyllium hydrogel nanocomposite for effective removal of polymethyl methacrylate nanoparticles and silver quantum dots pollutants

BackgroundPolymethyl methacrylate (PMMA) is widely used in biomedical applications. It exhibits slow degradation rates and thus is categorized as a potential hazardous pollutant. Similarly, silver quantum dots (Ag-QDs) have been recently listed as common pollutants based on their recent industrial applications. The aim is to design a novel nanocomposite via the combination of ferrofluids, covalent organic frameworks and Aminated alginate/Psyllium hydrogel as effective multifunctional nanocomposite for removal of PMMA nanoparticles (NPs) and Ag-QDs from water. MethodsDeveloped nanocomposite was fully identified from FTIR studies, electron microscopy, XRD and XPS. The removal process was optimized via detailed optimization of several parameters such as pH, shaking time (kinetic studies), nanocomposite dosage, pollutant concentration, temperature (thermodynamic studies) and ionic strength. Finally, the produced hybrid Ag-QDs@nanosorbent was examined as sustainable nanocatalyst for reducing Nitroxynil drug (NIX), a common hazardous pollutant Significant Findings98.02% and 96.36% removal efficiencies were achieved for PMMA NPs and Ag-QDs, respectively through process optimization.Kinetic studies revealed a complex heterogeneous chemisorption process that was interpreted by several kinetic models. Process spontaneity was confirmed from the thermodynamic studies. Process applicability in real water treatment of spiked samples with PMMA NPs and Ag-QDs as the target pollutants was accomplished. Finally, Ag-QDs@nanosorbent showed promising results as nanocatalyst for the pseudo-first order reduction of NIX with k=1.319 min−1.

A photonic hydrogel for health self-monitoring of solid-state electrolytes in zinc-air batteries

The solid-state electrolyte is one of the critical components of flexible zinc-air batteries, directly determining its discharge performance via water content. However, the health monitoring of solid-state electrolytes has long been neglected in practical applications due to the unique “half-open” structure of zinc-air batteries. Here, we first report a solid-state electrolyte health monitoring strategy based on photonic metamaterials. The double-network (DN) hydrogels formed by polyacrylamide (PAM) and sodium alginate (SA) were combined with photonic crystals (PhCs) self-assembled from polymethyl methacrylate (PMMA) nanoparticles to monitor the water content of solid-state electrolytes. The results demonstrate that the dehydration of solid-state electrolytes leads to the shrinkage of the gel volume and the structural color changes (blue shift) of PhCs, real-time monitoring the health of PAM-SA electrolyte and reflecting ionic conductivity of the electrolyte via optical signals. Moreover, a flexible zinc-air battery with the electrolyte of 275 mS cm–1 exhibits high charging-discharging efficiency (>80%), and the battery can work at the low temperature of -20 ℃. This work provides a strategy for the self-monitoring of solid-state batteries.

Understanding the biological impact of organic pollutants absorbed by nanoplastics

Many organisms are consuming food contaminated with micro- and nanoparticles of plastics, some of which absorb persistent organic pollutants (POPs) from the environment and acting as carrier vectors for increasing the bioavailability in living organisms. We recently reported that polymethylmethacrylate (PMMA) nanoparticles at low concentrations are not toxic to animal models tested. In this study, the toxicity of diphenylamine (DPA) incorporated PMMA nanoparticles are assessed using barnacle larvae as a model organism. The absorption capacity of DPA from water for commercially available virgin PMMA microparticles is relatively low (0.14 wt%) during a 48 h period, which did not induce exposure toxicity to barnacle nauplii. Thus, PMMA nanoparticles encapsulated with high concentrations of DPA (DPA-enc-PMMA) were prepared through a reported precipitation method to achieve 40% loading of DPA inside the particles. Toxicity of DPA-enc-PMMA nanoparticles were tested using freshly spawned acorn barnacle nauplii. The observed mortality of nauplii from DPA-enc-PMMA exposure was compared to the values obtained from pure DPA exposure in water. The mortality among the exposed acorn barnacle nauplii did not exceed 50% even at a high concentration of DPA inside the PMMA nanoparticles. The results suggest that the slow release of pollutants from polymer nanoparticles may not induce significant toxicity to the organism living in a dynamic environment. The impact of long-term exposure of DPA absorbed plastic nanoparticles need to be investigated in the future.

Evaluating shear in perfusion rotary lobe pump using nanoparticle aggregates and computational fluid dynamics.

Perfusion cell culture technology has gained a lot of interest in recent years in the biopharmaceutical industry. One common application is N-1 perfusion which is used to intensify fed batch production processes and increase facility output. Upon running our perfusion process for the first time at manufacturing scale, unexpected cell damage was observed. Reducing the recirculation pump speed resulted in improvements in cell viability which implied the impact of pump shear stress on cell viability. In this study, we used polymethyl methacrylate (PMMA) nanoparticles to determine the shear stress inside two different sized rotary lobe pumps used in N-1 perfusion. The results were used to validate a computational fluid dynamics (CFD) model to predict the maximum shear under different operating conditions of the pump. The CFD model identified the radial and mesh clearance zones as regions that experience the maximum shear stress inside the pump. The model was then used to evaluate the impact of different geometry modifications in the pump lobes, and it predicted a 17% reduction in the maximum shear stress by increasing the mesh and radial clearances by 0.08mm and 0.13mm, respectively. The study indicates that CFD can be a useful tool to predict shear stress inside rotary pumps. The results can be used to optimize the pump operating conditions or even customize the pump geometry to save time and cost of process scaling to manufacturing without compromising the preset operating conditions or critical scale-up parameters.

Effects of nanoplastics on zebrafish embryo-larval stages: A case study with polystyrene (PS) and polymethylmethacrylate (PMMA) particles

Plastic production has been rising consistently in the last 30 years and with it, the presence of plastic particles in the environment. A decrease in size often increases the bioavailability and reactivity of the particles. In this study the impact of polystyrene (PS; 22 nm) and polymethylmethacrylate (PMMA; 32 nm) nanoparticles on zebrafish embryo-larval stages was assessed by studying mortality, hatching, morphological features, and biochemical endpoints (associated with neurotransmission, antioxidant status and oxidative damage, and energy metabolism) after 96 h exposure, and swimming behavior after 120 h exposure. Organisms exposed to PMMA nanoparticles exhibited higher mortality and pericardial edema than those exposed to PS nanoparticles but displayed less effects on swimming behavior. Biochemical endpoints were altered to a higher degree in organisms exposed to PS nanoparticles (acetylcholinesterase, glutathione S-transferase and catalase activities) but higher peroxidative damage was found after exposure to lower concentrations of PMMA nanoparticles. Both types of nanoparticles affected energy metabolism with higher levels of glycogen found in animals exposed to PS nanoparticles. The use of integrated biomarker response index confirmed that PS nanoparticles had a higher impact on biochemical endpoints of zebrafish.

A comparative investigation of toxicity of three polymer nanoparticles on acorn barnacle (Amphibalanus amphitrite)

Pollution from plastic waste is increasingly prevalent in the environment and beginning to generate significant adverse impact on the health of living organisms. In this study, we investigate the toxicity of polymer nanoparticles exposed to Acorn Barnacle (Amphibalanus amphitrite) nauplii, as an animal model. Highly stable aqueous dispersion of luminescent nanoparticles from three common polymers: polymethylmethacrylate (PMMA), polystyrene (PS), and polyvinylchloride (PVC), were prepared via nanoprecipitation and fully characterised. Exposure studies of these polymer particles to freshly spawned barnacle nauplii were performed within a concentration range from 1 to 25 mg/L under laboratory-controlled conditions. The exposure to PMMA and PS nanoparticles did not show detrimental toxicity and did not cause sufficient mortality to compute a LC50 value. However, PVC nanoparticles were significantly toxic with a mortality rate of up to 99% at 25 mg/L, and the calculated LC50 value for PVC nanoparticles was 7.66 ± 0.03 mg/L, 95% CI. Interestingly, PVC nanoparticle aggregates were observed to adhere to the naupliar carapace and appendages at higher concentrations and could not be easily removed by washings. To explore the possibility of chemical toxicity of polymer nanoparticles, analysis of the polymer powders which was used to prepare the nanoparticles was conducted. The presence of low molecular weight oligomers such as dimers, trimers and tetramers were observed in all polymer samples. The chemical nature and concentration of such compounds are likely responsible for the observed toxicity to the barnacle nauplii. Overall, our study shows that care should be exercised in generalising the findings of exposure studies performed using one type of plastic particles, as the use of different plastic particles may elicit different responses inside a living organism.

Effect of Polymer Nano- and Microparticles on Calcium Carbonate Crystallization.

Molecular and macromolecular templates are known to affect the shape, size, and polymorph selectivity on the biomineralization of calcium carbonate (CaCO3). Micro- and nanoparticles of common polymers present in the environment are beginning to show toxicity in living organisms. In this study, the role of plastic nanoparticles in the biomineralization of CaCO3 is explored to understand the ecological impact of plastic pollution. As a model study, luminescent poly(methyl methacrylate) nanoparticles (PMMA-NPs) were prepared using the nanoprecipitation method, fully characterized, and used for the mineralization experiments to understand their influence on nucleation, morphology, and polymorph selectivity of CaCO3 crystals. The PMMA-NPs induced calcite crystal nucleation with spherical morphologies at high concentrations. Microplastic particles collected from a commercial face scrub were also used for CaCO3 nucleation to observe the nucleation of calcite crystals on the particle surface. Microscopic, spectroscopic, and X-ray diffraction data were used to characterize and identify the nucleated crystals. The data presented in this paper add more information on the impact of microplastics on the marine environment.

Shirasu porous glass membrane processed uniform-sized Fe3O4-embedded polymethylmethacrylate nanoparticles and their tunable rheological response under magnetic field

We fabricated Fe3O4-polymethylmethacrylate (PMMA) magnetic composite nanoparticles using the Shirasu porous glass membrane process and investigated the magneto-responsive magnetorheological (MR) response of them under various applied magnetic fields when dispersed in silicone oil. The morphology and structure of the particles were observed through transmission electron microscopy, Fourier Transform-infrared spectroscopy, and X-ray diffraction. In addition, a typical MR behavior was confirmed when the MR fluid of the Fe3O4-PMMA nanoparticles was evaluated by a rotation rheometer under applied magnetic fields. The synthesized Fe3O4-PMMA magnetic composite nanoparticles exhibited a promising potential for application in a wide range of MR application prospects owing to its appropriate size, lower density, and better sedimentation stability.

Controlled soap-free emulsion polymerization stability using a novel cationic azo radical initiator with chloride or triflate counter anion

In our previous work, we developed a novel cationic azo radical initiator, 2,2′-azobis-[2-(1,3-dimethyl-4,5-dihydro-1H-imidazol-3-ium-2-yl)]propane triflate (ADIP) to prepare cationic and hydrophilic polymer particles for incorporation into cells. To apply this cationic radical initiator to hydrophobic polymer particles for a broader range of industrial applications, we attempted to synthesize polymethylmethacrylate (PMMA) latex via surfactant-free emulsion polymerization (SFEP). However, we found that the synthesized emulsion coagulated and contained a wide-size distribution of the particles, resulting in the failure of stable emulsion polymerization. In this study, we have successfully synthesized cationic PMMA particles with a narrow size distribution without any coagulation using ADIP-Cl which is an ADIP derivative in which the triflate counter anion was replaced with chloride. Compared to other halides and polyatomic anions, the triflate anion caused a significant aggregation of the PMMA particles. Furthermore, we confirmed that ADIP-Cl can be also applicable for the size-controlled synthesis of PMMA nanoparticles with sub-100 nm size in an acetone-water mixture. We envision that polymer particles prepared by ADIP-Cl via SFEP can contribute to the design of various functional materials.

Effect of Curcumin Coated with Polymethyl Methacrylate Nanoparticles on Lung Cancer Cells

Lung cancer is a malignant tumor with an extremely high incidence and mortality rate in clinical practice and its pathogenesis remains unclear at present. Currently, the methods for treating this disease have relatively high limitations. However, with the gradual maturity and application of nanotechnology, a number of studies have pointed out that polymethyl methacrylate nanoparticles (PMMA-NPs) encapsulated with curcumin (Cur) possibly becomes a new and effective scheme for treating lung cancer. First of all, Cur-PMMA-NPs were prepared. Their sizes were determined by characterization techniques, and their effects on lung cancer cells A549 were detected by Cell proliferation experiment and flow cytometry. The expression of apoptosis-related proteins in the cells was detected by Western blotting. The results showed that polyacrylic acid (PAA)-Cur-PMMA-NPs had a particle size of (215.00±6.00) nm. The drug loading rate and the encapsulation rate of nanospheres were remarkably higher than those of free Cur (P < 0.05). After the intervention of PAA-Cur-PMMA-NPs in the cells, the cell proliferation and the Bcl-2 expression reduced, while the apoptotic rate and the expression of Bax, Caspase-3, and Caspase-9 increased (P < 0.05). Accordingly, Cur-PMMA-NPs can inhibit lung cancer cells from growth and induce their apoptosis, so they are expected to become an effective intervention measure to improve the therapeutic effect on lung cancer in the future.

A Nanostructured Microfluidic Artificial Olfaction for Organic Vapors Recognition

Selective and sensitive detection of volatile organic compounds (VOCs) is of great importance in applications involving monitoring of hazardous chemicals or non-invasive diagnosis. Here, polymethyl methacrylate nanoparticles with acetone recognition sites are synthesized and integrated into a 3D-printed microfluidic platform to enhance the selectivity of the device. The proposed microfluidic-based olfaction system includes two parylene C-coated microchannels, with or without polymer nanoparticles. The two channels are exposed to 200, 400, 800, 2000, and 4000 ppm of VOCs (methanol, ethanol, acetone, acetonitrile, butanone, and toluene), and sensor responses are compared using a 2D feature extraction method. Compared to current microfluidic-based olfaction systems, responses observed between coated and uncoated channels showed an increased recognition capability among VOCs (especially with respect to acetone), indicating the potential of this approach to increase and fine-tune the selectivity of microfluidic gas sensors.

Morphology stability of polymethylmethacrylate nanospheres formed in water–acetone dispersion medium

The aim of this study is to develop a manufacturing technique of polymethylmethacrylate (PMMA) nanospheres to produce a more stable opal template. Water–acetone mixture was used as a dispersion medium to synthesize a PMMA opal structure. Morphology features, IR vibrational spectra and glass transition temperatures of the PMMA nanospheres formed in the water–acetone dispersion medium (nanospheres A) have been studied comparing with the same prepared in distilled water solution without acetone (nanospheres B). A dependence of a shrinkage degree of the nanoparticles on the acetone volume has been investigated. It has been revealed that under an electron beam action the shrinkage degree of the nanospheres A is in the range of 7–16% while the shrinkage of the nanospheres B is 18–25% at the same conditions. The nanospheres A are less flexible and soft as compared to the nanospheres B. Additionally, an ability of the PMMA nanoparticles fabricated in the water–acetone dispersion medium to form the ordered opal structures is demonstrated to be the similar to the nanospheres B.

PMMA-BN composites incorporated with Au nanoparticle fabricated by laser ablation

As a class of layered materials, two dimensional (2D) materials have attracted great attention all around the world due to their inherent use for next generation nano technology devices. We can see 2D materials including carbon in our daily life and at many places, for instance, graphite, diamond and so on. New study is also being conducted to produce new functional materials by combining 2D material and polymer. Hexagonal boron nitride (h-BN) which is one kind of 2D material is dispersed in Poly methyl methacrylate (PMMA) or poly styrene (PS). The composite material of h-BN coated with polymer shows an improvement in the properties such as the higher thermal conductivity and higher mechanical strength. In this study, the composite material of PMMA, h-BN and gold nanoparticles has been synthesized. Boron nitride nano-structures were prepared by nanosecond laser ablation in acetone and was carried out at room temperature with laser ablation time of 120 min. The PMMA films were made by PMMA granules dissolved in acetone solvent and then mix with h-BN and gold colloid solution. The prepared composite films were characterized by scanning electron microscopy (SEM), and UV-vis spectroscopy. Such type of unique 2D nano-composite materials make their mark for the future exploitation in electronics and nanocomposite-related applications.

Synthesis and characterization of poly(methyl methacrylate)-boehmite nanocomposites by direct microemulsion polymerization combined with the in-situ sol-gel method

Polymethyl methacrylate - boehmite nanocomposites (PMMA-x-BNCs; where x = 10.0 and 20.0 wt % of PMMA nanoparticles in the latexes) were synthesized by a procedure in two steps. Firstly, polymethyl methacrylate nanoparticles (PMMA-NPs) were prepared either without or with the addition of divinyl benzene as cross-linking agent by semicontinue-direct microemulsion polymerization. Secondly, PMMA-NPs were added to aluminum sec-butoxide solution to obtain PMMA-x-BNCs, by the in-situ sol-gel preparation method. The PMMA-x-BNCs samples were annealed at 300 °C for 4 h and characterized by X-ray diffraction (XRD), electron transmission microscopy (TEM), scanning electron microscopy (SEM), differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), N2 physisorption, Fourier-transform infrared spectroscopy (FTIR), Raman spectroscopy, X-ray photoelectron spectroscopy (XPS), ultraviolet–visible (UV–Vis) and photoluminescence (PL) spectroscopies. The PMMA-x-BNCs nanocomposites, mainly those containing cross-linked PMMA-NPs showed enhanced absorption of UV and visible light. The band gap energy (Eg) of PMMA-x-BNCs decreased to a level comparable to that of a semiconductor material. The carbon residues and the remaining carbonyl group of PMMA after the annealing process promoted the improvement of the specific surface area, the decrease in the Eg and the inhibition of the recombination rate of electron-hole pairs.

Core–shell poly-methyl methacrylate nanoparticles covalently functionalized with a non-symmetric porphyrin for anticancer photodynamic therapy

Photodynamic therapy (PDT) is an anticancer modality that exploits singlet oxygen and other reactive oxygen species, that are formed by selective irradiation of photosensitive molecules, to kill cancer cells. Most photosensitizers (PS) are hydrophobic and poorly soluble in water and several nanoplatforms have been established to achieve a more efficient delivery. Moreover, the covalent binding of the PS to nanoparticles could in principle reduce unwanted bleaching of the PS, while preserving its photodynamic activity. In this study we report the synthesis of a novel non-symmetrical diaryl-porphyrin suitably modified with a polymerizable pendant, that was used for the preparation of core-shell poly-methyl methacrylate nanoparticles covalently loaded with the diaryl-porphyrin (PMMA@PorVa). Particles, which were prepared with two different porphyrin loadings, are spherical in shape and with a narrow hydrodynamic diameter around 70 nm and a positive zeta potential. Their photo-toxicity was tested against the human colon carcinoma cell line HCT116 and the human ovarian adenocarcinoma cell line SKOV3. PMMA@PorVa were able to inhibit tumor cells proliferation similarly to the free porphyrin, thus confirming that the covalent attachment of the PS to PMMA nanoparticles allows to preserve PS photodynamic activity and in vitro efficacy. Flow cytometric analysis of apoptotic cells demonstrates that, especially in SKOV3 cells, the free diaryl-porphyrin is more effective in inducing apoptosis.