Polymeric nanocapsules and nanospheres for encapsulation and long sustained release of hydrophobic cyanine-type photosensitizer

Study of PEG-b-PLA/Eudragit S100 Blends on the Nanoencapsulation of Indigo Carmine Dye and Application in Controlled Release

A nanocapsule shell of poly(ethylene glycol)-block-poly(d,l-lactic acid) (PEG-b-PLA) mixed with anionic Eudragit S100 (90/10% w/w) was previously used to entrap and define the self-assembly of indigo carmine (IC) within the hydrophilic cavity core. In the present work, binary blends were prepared by solution mixing at different PEG-b-PLA/Eudragit S100 ratios (namely, 100/0, 90/10, 75/25, and 50/50% w/w) to elucidate the role of the capsule shell in tuning the encapsulation of the anionic dye (i.e., IC). The results showed that the higher content of Eudragit S100 in the blend decreases the miscibility of the two polymers due to weak intermolecular interactions between PEG-b-PLA and Eudragit S100. Moreover, with an increase in the amount of Eudragit S100, a higher thermal stability was observed related to the mobility restriction of PEG-b-PLA chains imposed by Eudragit S100. Formulations containing 10 and 25% Eudragit S100 exhibited an optimal interplay of properties between the negative surface charge and the miscibility of the polymer blend. Therefore, the anionic character of the encapsulating agent provides sufficient accumulation of IC molecules in the nanocapsule core, leading to dye aggregates following the self-assembly. At the same time, the blending of the two polymers tunes the IC release properties in the initial stage, achieving slow and controlled release. These findings give important insights into the rational design of polymeric nanosystems containing organic dyes for biomedical applications.

Triple-layered platform utilizing electrospun nanofibers and 3D-printed sodium alginate-based hydrogel for effective topical treatment of rheumatoid arthritis

Rheumatoid arthritis (RA), an autoimmune disease impacting the joints, significantly diminishes the quality of life for patients. Conventional treatments predominantly rely on oral or injectable formulations, underscoring the crucial need for an effective topical remedy. The present study reports a novel triple-layered transdermal platform for efficient RA treatment. The patches are based on an electrospun/electrosprayed diclofenac (DIC)-conjugated polyvinyl alcohol (PVA) nanofibers/nanoparticles (NFs/NPs) composite layer sandwiched between an electrospun supporting layer of polycaprolactone (PCL) NFs, and a 3D-printed sodium alginate-based hydrogel (HG) layer incorporating sodium hyaluronate (HA) and rosuvastatin (ROS)-loaded core-shell lipid nanocapsules (LNCs). The ingeniously designed transdermal patches release the chemically conjugated DIC via skin-secreted esterases at the inflamed sites. The LNCs and patches were characterized using DLS, FTIR, DSC, and electron microscopy. ROS-loaded LNCs (<50 nm as per the TEM micrographs) were able to release about 97 % of ROS during 5 days. In-vitro and in-vivo evaluations definitively established the efficacy of the developed platform, showcasing a substantial reduction in IL-6 and TNF-α through sandwich ELISA measurements in cell culture and Rattus norvegicus plasma samples. Besides, the stained photomicrographs of the rats' ankle joints confirmed the alleviation of the RA symptoms via reducing cell infiltration with a preserved joint tissue structure.

Lipid-Based Nanoparticles for Drug/Gene Delivery: An Overview of the Production Techniques and Difficulties Encountered in Their Industrial Development

Over the past decade, the therapeutic potential of nanomaterials as novel drug delivery systems complementing conventional pharmacology has been widely acknowledged. Among these nanomaterials, lipid-based nanoparticles (LNPs) have shown remarkable pharmacological performance and promising therapeutic outcomes, thus gaining substantial interest in preclinical and clinical research. In this review, we introduce the main types of LNPs used in drug formulations such as liposomes, nanoemulsions, solid lipid nanoparticles, nanostructured lipid carriers, and lipid polymer hybrid nanoparticles, focusing on their main physicochemical properties and therapeutic potential. We discuss computational studies and modeling techniques to enhance the understanding of how LNPs interact with therapeutic cargo and to predict the potential effectiveness of such interactions in therapeutic applications. We also analyze the benefits and drawbacks of various LNP production techniques such as nanoprecipitation, emulsification, evaporation, thin film hydration, microfluidic-based methods, and an impingement jet mixer. Additionally, we discuss the major challenges associated with industrial development, including stability and sterilization, storage, regulatory compliance, reproducibility, and quality control. Overcoming these challenges and facilitating regulatory compliance represent the key steps toward LNP's successful commercialization and translation into clinical settings.

Polymeric and Composite Carriers of Protein and Non-Protein Biomolecules for Application in Bone Tissue Engineering

Conventional intake of drugs and active substances is most often based on oral intake of an appropriate dose to achieve the desired effect in the affected area or source of pain. In this case, controlling their distribution in the body is difficult, as the substance also reaches other tissues. This phenomenon results in the occurrence of side effects and the need to increase the concentration of the therapeutic substance to ensure it has the desired effect. The scientific field of tissue engineering proposes a solution to this problem, which creates the possibility of designing intelligent systems for delivering active substances precisely to the site of disease conversion. The following review discusses significant current research strategies as well as examples of polymeric and composite carriers for protein and non-protein biomolecules designed for bone tissue regeneration.

Exploring the potential of intranasally administered naturally occurring quercetin loaded into polymeric nanocapsules as a novel platform for the treatment of anxiety

Anxiety is one of the most prevalent forms of psychopathology that affects millions worldwide. It gained more importance under the pandemic status that resulted in higher anxiety prevalence. Anxiolytic drugs such as benzodiazepines have an unfavorable risk/benefit ratio resulting in a shift toward active ingredients with better safety profile such as the naturally occurring quercetin (QRC). The delivery of QRC is hampered by its low water solubility and low bioavailability. The potential to enhance QRC delivery to the brain utilizing polymeric nanocapsules administered intranasally is investigated in the current study. Polymeric nanocapsules were prepared utilizing the nanoprecipitation technique. The best formula displayed a particle size of 227.8 ± 11.9 nm, polydispersity index of 0.466 ± 0.023, zeta potential of - 17.5 ± 0.01 mV, and encapsulation efficiency % of 92.5 ± 1.9%. In vitro release of QRC loaded polymeric nanocapsules exhibited a biphasic release with an initial burst release followed by a sustained release pattern. Behavioral testing demonstrated the superiority of QRC loaded polymeric nanocapsules administered intranasally compared to QRC dispersion administered both orally and intranasally. The prepared QRC loaded polymeric nanocapsules also demonstrated good safety profile with high tolerability.

Use of graft materials and biologics in spine deformity surgery: a state-of-the-art review

PURPOSE

The aim of the current review is to summarize the current evidence on graft materials used in fusion procedures for spinal deformity corrections.

METHODS

PubMed, Embase, and Cochrane Library were searched for relevant published observational studies and clinical trials using osteobiologics and biomaterials in spinal deformity surgery.

RESULTS

The use of autograft in deformity correction surgeries has been reported in a limited number of studies, with the harvest sites including iliac crest, ribs, and local bone. Various allografts and biologics have been used in the treatment of spinal deformities including idiopathic and degenerative scoliosis, either as stand alone or in combination with autograft. Limited number of studies reported no differences in fusion rates or outcomes. Use of rh-BMP2 in anterior, posterior or front/back approaches showed higher fusion rates than other graft materials in patients with spinal deformities. Due to the limited number of quality studies included in the review, as well as alternative factors, such as costs, availability, and surgeon expertise/preference, no definitive conclusion or recommendations can be made as to the ideal graft choice in spinal deformity surgery.

CONCLUSIONS

Most commonly used grafts included autograft, allograft and rh-BMP2, with new biologics and biomaterials constantly emerging in the market. Limited number of high-quality comparative studies and heterogeneity in study design prevented direct comparisons that can lead to meaningful recommendations. Further studies are needed to prove superiority of any single graft material and/or biologic that is also cost-effective and safe.

Hollow microneedle assisted intradermal delivery of hypericin lipid nanocapsules with light enabled photodynamic therapy against skin cancer

Photodynamic therapy (PDT) to manage non-melanoma skin cancers has garnered great attention over the past few years. Hypericin (Hy) is a potent lipid-soluble photosensitiser with promising anticancer therapeutic activities. Nevertheless, its poor water-solubility, aggregation in biological systems and insufficient skin penetration restricted its effective exploitation. Herein, we report for the first-time encapsulation of Hy into lipid nanocapsules (Hy-LNCs), and then application of an AdminPen™ hollow microneedles (Ho-MNs) array and an in-house fabricated Ho-MN to enable efficient intradermal delivery. The physicochemical properties, photoactivity, ex vivo drug distribution and cellular uptake were evaluated. Results showed that Hy-LNCs were successfully formed with a particle size of 47.76 ± 0.49 nm, PDI of 0.12 ± 0.02, high encapsulation efficiency (99.67% ± 0.35), 396 fold higher photoactivity, 7 fold higher skin drug deposition, significantly greater cellular uptake and higher photocytotoxicity compared to free Hy. The therapeutic effect of Hy-LNCs was finally assessed in vivo using a nude mouse model with transplanted tumours. Interestingly, Hy-LNCs delivered by Ho-MN exhibited remarkable anti-tumour destruction (85.84%) after irradiation with 595 nm. This study showed that Ho-MNs-driven delivery of Hy-LNCs followed by irradiation could form a promising minimally invasive, effective and site-specific approach for managing non-melanoma skin cancers.

Multifunctional phototheranostic nanoplatform based on polydopamine-manganese dioxide-IR780 iodide for effective magnetic resonance imaging-guided synergistic photodynamic/photothermal therapy

Multifunctional phototheranostics combining diagnostic and therapeutic modalities may provide a revolutionary opportunity for cancer treatment. As a promising tumor phototheranostic molecule, IR780 iodide (IR780) shows excellent photodynamic and photothermal performance under near-infrared laser irradiation; however, its hydrophobicity and instability limit its further use in organisms. This work demonstrates the design and development of a multifunctional nanoplatform (PMIDA, referring to polydopamine (PDA)-manganese dioxide (MnO₂)-IR780) for imaging-guided phototherapy. The good biocompatibility of PDA greatly improves the water solubility and photostability of IR780, and its excellent photothermal properties make PMIDA a dual photothermal therapy (PTT). MnO₂-induced generation of oxygen in the tumor microenvironment improves the hypoxia effect and photodynamic therapy (PDT) of IR780. Moreover, Mn²⁺ serves as a decent T₁-weighted magnetic resonance imaging (MRI) probe to guide treatment. Notably, in relevant cellular assays, PMIDA shows high photodynamic and photothermal effects contributing to the final therapeutic effect. The MRI-guided PDT/PTT synergistic therapy effect in vivo is demonstrated by precise tumor diagnosis and complete tumor elimination outcomes. Based on these experiments, PMIDA nanoparticles display promising effects in facilitating intravenous injection of IR780 and achieving magnetic resonance imaging (MRI)-guided phototheranostic efficacy for tumor treatment.

Production of doxorubicin-loaded PCL nanoparticles through a flow-focusing microfluidic device: encapsulation efficacy and drug release

The present study shows a facile route for producing doxorubicin (DOX)-loaded polycaprolactone (PCL) nanoparticles using a microfluidic device with a flow-focusing platform in a single step. Indeed, the evaluation of the performance of the flow-focusing microfluidic device for the preparation of DOX-loaded PCL (DOX/PCL) nanoparticles with a uniform size distribution and high encapsulation efficiency (EE) by applying the liquid non-solvent precipitation process is very important. Accordingly, the physicochemical characteristics of the DOX/PCL nanoparticles such as their mean size, polydispersity index (PDI), and EE were investigated by studying different parameters such as the flow rate ratio (FRR) and DOX concentration. Also, the release study was carried out at two pH of 5.5 and 7.4. The mean size of DOX/PCL nanoparticles achieved was in the range of 120-320 nm with a PDI ≤ 0.29 and EE between 48% and 87%. Moreover, the release profile of DOX/PCL nanoparticles was sustained for 10 days (≤66%) at pH 7.4. This means that the production process can result in a high EE and low release of the DOX drug.

Docetaxel in chitosan-based nanocapsules conjugated with an anti-Tn antigen mouse/human chimeric antibody as a promising targeting strategy of lung tumors

The aim of this work was to evaluate the physicochemical and biological properties of docetaxel (DCX) loaded chitosan nanocapsules (CS Nc) functionalized with the monoclonal antibody Chi-Tn (CS-PEG-ChiTn mAb Nc) as a potential improvement treatment for cancer therapy. The Tn antigen is highly specific for carcinomas, and this is the first time that such structure is targeted for drug delivery. The nanocapsules (Ncs), formed as a polymeric shell around an oily core, allowed a 99.9% encapsulation efficiency of DCX with a monodispersity particle size in the range of 200 nm and a high positive surface charge that provide substantial stability to the nanosystems. Release profile of DCX from Ncs showed a sustained and pH dependent behavior with a faster release at acidic pH, which could be favorable in the intracellular drug delivery. We have designed PEGylated CS Nc modified with a monoclonal antibody which recognize Tn antigen, one of the most specific tumor associated antigen. A biotin-avidin approach achieved the successful attachment of the antibody to the nanocapsules. Uptake studies and viability assay conducted in A549 human lung cancer cell line in vitro demonstrate that ChiTn mAb enhance nanoparticles internalization and cell viability reduction. Consequently, these ChiTn functionalized nanocapsules are promising carriers for the active targeting of DCX to Tn expressing carcinomas.

Dexamethasone-Loaded Lipomers: Development, Characterization, and Skin Biodistribution Studies

Follicular targeting has gained more attention in recent decades, due to the possibility of obtaining a depot effect in topical administration and its potential as a tool to treat hair follicle-related diseases. Lipid core ethyl cellulose lipomers were developed and optimized, following which characterization of their physicochemical properties was carried out. Dexamethasone was encapsulated in the lipomers (size, 115 nm; polydispersity, 0.24; zeta-potential (Z-potential), +30 mV) and their in vitro release profiles against dexamethasone in solution were investigated by vertical diffusion Franz cells. The skin biodistribution of the fluorescent-loaded lipomers was observed using confocal microscopy, demonstrating the accumulation of both lipomers and fluorochromes in the hair follicles of pig skin. To confirm this fact, immunofluorescence of the dexamethasone-loaded lipomers was carried out in pig hair follicles. The anti-inflammatory (via TNFα) efficacy of the dexamethasone-loaded lipomers was demonstrated in vitro in an HEK001 human keratinocytes cell culture and the in vitro cytotoxicity of the nanoformulation was investigated.

Targeted Hybrid Nanocarriers as a System Enhancing the Skin Structure

The skin is constantly exposed to external and internal factors that disturb its function. In this work, two nanosystems-levan nanoparticles and a surfactin-stabilized nanoemulsion were preserved (tested for microbial growth) and characterized (size, polydispersity, Zeta potential, and stability). The nanosystems were introduced in the model formulations-cream, tonic, and gel, and confirmed by TEM. The analysis showed that nanoemulsion has a spherical morphology and size 220–300 nm, while levan nanoparticles had irregular shapes independently of the use of matrix and with particle size (130–260 nm). Additionally, we examined the antiradical effect of levan nanoparticles and nanoemulsion in the prototype of formulations by scavenging DPPH (2,2-diphenyl-1-picrylhydrazyl; EPR spectroscopy). The model cream with both nanosystems and the whole range of products with nanosystems were evaluated in vivo for hydration, elasticity, smoothness, wrinkles and vascular lesions, discoloration, respectively. The cream improved skin condition in all tested parameters in at least 50% of volunteers. The use of more comprehensive care, additionally consisting of a tonic and gel, reduced the previously existing skin discoloration to 10.42 ± 0.58%. The presented prototype formulations are promising in improving skin conditions.

Physicochemical properties of L-alpha dipalmitoyl phosphatidylcholine large unilamellar vesicles: Effect of hydrophobic block (PLA/PCL) of amphipathic diblock copolymers

In the present work, we show how amphipathic diblock copolymers affect the physicochemical properties of the lipid bilayer of DPPC liposome. Diblock copolymers proposed for this study are focused in the difference between PLA and PCL hydrophobic block, because PLA and PCL differ in their glass transition temperature, where a higher ratio of PLA, lowers the flexibility of the diblock copolymer. On the contrary, a greater proportion of PCL makes the diblock copolymer more flexible. This flexibility difference between hydrophobic block would affect the physicochemical properties of lipid bilayer of DPPC. The difference of rigidity or flexibility of hydrophobic block and their interaction with DPPC large unilamellar vesicles (LUVs) was evaluated at low and high copolymers concentration. The copolymer concentrations used were chosen based on their respective cmc. We measure (a) Thermotropic behavior from GP of Laurdan and fluorescence anisotropy of DPH; (b) Relation between wavelength excitation and generalized polarization of Laurdan; (c) Time-resolved fluorescence anisotropy of DPH; (d) Water outflow through the lipid bilayer and (e) calcein release from DPPC LUVs. Furthermore, large unilamellar vesicles in the absence and in the presence of different copolymers were characterized by size and zeta-potential. The results show that the diblock copolymer at high PLA/PCL ratio, that is, greater rigidity of hydrophobic block produces an increase of the phase transition temperature (Tm). For DPPC LUVs, Tm increase 3.5 °C at low and about 4.5 °C at high copolymers concentration, sensed by Laurdan and DPH fluorescent probes, although the DPPC/copolymers molar ratio for Cop4 is higher than Cop3, Cop2 and Cop1. In addition, we observed a decrease in the polarity of microenvironments in the bilayer and an increase in the order of the acyl chains in the bilayer to a high proportion of PLA. Furthermore, the presence of diblock copolymer with high proportion of PLA, decreases water outflow from DPPC liposome and water efflux is slower; leading to a decrease in calcein release from DPPC liposomes. Our results clearly show that the greater the stiffness of the hydrophobic block, greater degree of packaging of the lipid bilayer, greater the order of the acyl chains, and greater retention of water and calcein inside the liposome. Therefore, the presence of AB-type diblock copolymers with a more rigid hydrophobic block, stabilizes the lipid bilayer and would allow a more controlled release of water, and encapsulated molecules inside of the DPPC liposome.

Design, Formulation and in vivo Evaluation of Novel Honokiol-Loaded PEGylated PLGA Nanocapsules for Treatment of Breast Cancer

Background

Honokiol (HK) is a common herbal medicine extracted from magnolia plants. Low aqueous solubility and limited bioavailability of HK have hindered its clinical application, especially for cancer treatment. Nano-drug delivery system has the potential to enhance HK delivery and therefore, enhance its anti-cancer activity.

Purpose

The study’s aim is to design novel PEGylated-PLGA polymeric nanocapsules (NCs) for HK delivery to breast tumor-bearing mice after systemic administration.

Methods

Formulation of different HK-loaded NCs and their physio-chemical characterization were optimized through the use of different formulation variables. The antitumor activity of the HK-loaded NCs was investigated both in vitro using MCF-7 and EAC breast cancer cell lines and in vivo using solid Ehrlich carcinoma (SEC) breast cancer model.

Results

The optimum HK-loaded NCs were prepared from 15% PEG-PLGA diblock copolymer and exhibited the lowest nano size of 125 nm, smooth spherical morphology, highest drug loading of 94% and highest cellular uptake into breast cancer cells. HK-loaded PEGylated NCs can effectively inhibit the in vitro cell growth of breast cancer cells by 80.2% and 58.1% compared to 35% and 31% with free HK in the case of MCF-7 and EAC, respectively. HK-loaded NCs inhibited SEC tumor growth by 2.3 fold significantly higher than free HK, in vivo.

Conclusion

The designed drug delivery system encapsulating HK exhibited a pronounced decrease in tumor growth biomarkers meanwhile proved its safety in animals. Therefore, 15% PEGylated HK-loaded NCs may act as a promising new approach for breast cancer treatment.

Prototypic Heptamethine Cyanine Incorporating Nanomaterials for Cancer Phototheragnostic

Developing technologies that allow the simultaneous diagnosis and treatment of cancer (theragnostic) has been the quest of numerous interdisciplinary research teams. In this context, nanomaterials incorporating prototypic near infrared (NIR)-light responsive heptamethine cyanines have been showing very promising results for cancer theragnostic. The precisely engineered features of these nanomaterials endow them with the ability to achieve a high tumor accumulation, enabling a tumor's visualization by NIR fluorescence and photoacoustic imaging modalities. Upon interaction with NIR light, the tumor-homed heptamethine cyanine-incorporating nanomaterials can also produce a photothermal/photodynamic effect with a high spatio-temporal resolution and minimal side effects, leading to an improved therapeutic outcome. This progress report analyses the application of nanomaterials incorporating prototypic NIR-light responsive heptamethine cyanines (IR775, IR780, IR783, IR797, IR806, IR808, IR820, IR825, IRDye 800CW, and Cypate) for cancer photothermal therapy, photodynamic therapy, and imaging. Overall, the continuous development of nanomaterials incorporating the prototypic NIR absorbing heptamethine cyanines will cement their phototheragnostic capabilities.

Trazodone Loaded Lipid Core Poly (ε-caprolactone) Nanocapsules: Development, Characterization and in Vivo Antidepressant Effect Evaluation

Trazodone hydrochloride (TRH) is a lipophilic drug which is used effectively as an antidepressant. Its poor solubility and short half-life represent an obstacle for its successful use. Nanocapsules with biodegradable polymeric shell are successful drug delivery systems for controlling the release of drugs. To enhance the entrapment of lipophilic drugs, oils can be added forming a lipophilic core in which the drug is more soluble. The aim of this study was to enhance the efficacy of TRH and prolong its action by formulating it into lipid core polymeric shell nanocapsules. Nanocapules were prepared using nanoprecipitation technique. All prepared formulations were in nano size range and negatively charged. The TRH entrapment efficiency (EE%) in lipid core nanocapsules was up to 74.8 ± 0.5% when using Labrafac lipophile as a lipid core compared to only 55.7 ± 0.9% in lipid free polymeric nanospheres. Controlled TRH release was achieved for all prepared formulations. Forced swim test results indicated the significant enhancement of antidepressant effect of the selected TRH loaded Labrafac lipophile core nanocapsules formulation compared to control and TRH dispersion in phosphate buffer. It is concluded that lipid core nanocapsules is a promising carrier for the enhancement of TRH efficacy.

Near-infrared heptamethine cyanines (Cy7): from structure, property to application

Heptamethine cyanine dyes (Cy7) have attracted much attention in the field of biological application due to their unique structure and attractive near infrared (NIR) photophysical properties.

Polyphosphoester-Based Nanocarrier for Combined Radio-Photothermal Therapy of Breast Cancer

Recently, clinical research on tumor therapy has gradually shifted from traditional monotherapy toward combination therapy as tumors are complex, diverse, and heterogeneous. Combination therapy may be essential for achieving the optimized treatment efficacy of tumors through distinct tumor-inhibiting mechanisms. At the same time, nanocarriers are emerging as an excellent strategy for delivering both drugs simultaneously. This work presents utilization of a polyphosphoester-based nanocarrier (NP_IR/Cur) to achieve the codelivery of hydrophobic photothermal agent IR-780 and radiosensitizer curcumin (Cur). The IR-780 and curcumin coencapsulated NP_IR/Cur exhibited adequate drug loading, a prolonged blood half-life, enhanced passive tumor homing, and improved curcumin bioavailability as well as combined therapeutic functions. Briefly, NP_IR/Cur could not only achieve effective thermal ablation through the conversion of near-infrared light to heat, but also give rise to a significant boosted local radiation dose to trigger promoted radiation damages, thus resulting in enhanced tumor cell growth inhibition. In conclusion, the as-prepared NP_IR/Cur manifested excellent performance in facilitating combined photothermal and radiation therapy, thus expanding the application range of PPE-based carriers in nanomedicine, and also prompting exploration of their potential for other effective combination therapies.

Diosgenin-conjugated PCL–MPEG polymeric nanoparticles for the co-delivery of anticancer drugs: design, optimization, in vitro drug release and evaluation of anticancer activity

In this study, a polymeric nanoparticle-mediated dual anti-cancer drug delivery system was designed and developed.

Recent progress in the engineering of multifunctional colloidal nanoparticles for enhanced photodynamic therapy and bioimaging

This up-to-date review summarizes the design and current fabrication strategies that have been employed in the area of mono- and multifunctional colloidal nanoparticles - nanocarriers well suited for photodynamic therapy (PDT) and diagnostic purposes. Rationally engineered photosensitizer (PS)-loaded nanoparticles may be achieved via either noncovalent (i.e., self-aggregation, interfacial deposition, interfacial polymerization, or core-shell entrapment along with physical adsorption) or covalent (chemical immobilization or conjugation) processes. These PS loading approaches should provide chemical and physical stability to PS payloads. Their hydrophilic surfaces, capable of appreciable surface interactions with biological systems, can be further modified using functional groups (stealth effect) to achieve prolonged circulation in the body after administration and/or grafted by targeting agents (such as ligands, which bind to specific receptors uniquely expressed on the cell surface) or stimuli (e.g., pH, temperature, and light)-responsive moieties to improve their action and targeting efficiency. These attempts may in principle permit efficacious PDT, combination therapies, molecular diagnosis, and - in the case of nanotheranostics - simultaneous monitoring and treatment. Nanophotosensitizers (nano-PSs) should possess appropriate morphologies, sizes, unimodal distributions and surface processes to be successfully delivered to the place of action after systemic administration and should be accumulated in certain tumors by passive and/or active targeting. Additionally, physically facilitating drug delivery systems emerge as a promising approach to enhancing drug delivery, especially for the non-invasive treatment of deep-seated malignant tissues. Recent advances in nano-PSs are scrutinized, with an emphasis on design principles, via the promising use of colloid chemistry and nanotechnology.

Poly(l-glutamic acid)-g-poly(ethylene glycol) external layer in polyelectrolyte multilayer films: Characterization and resistance to serum protein adsorption

Formation of protein-resistant surfaces is a major challenge in the design of novel biomaterials and an important strategy to prevent protein adsorption is the formation of protein-resistant coatings. It can be achieved by proper modification of surfaces, e.g., by immobilization of hydrophilic polymers such as poly(ethylene glycol) (PEG). An appropriate method to immobilize PEG at charged surfaces is the adsorption of copolymers with PEG chains grafted onto polyelectrolyte backbone. The growing interest in the use of polyelectrolyte multilayer coatings in biomedical applications to improve biocompatibility and/or to prepare coating with antiadhesive properties has been the main reason for these studies. Therefore the aim was to produce protein resistant polyelectrolyte multilayer films. They were formed via the layer-by-layer approach, while their pegylation by the deposition of pegylated polyanion, PGA-g-PEG, as an external layer. The influence of PEG chain length and grafting density of PGA-g-PEG copolymers on the protein antiadhesive properties of pegylated polyelectrolyte multilayer films was investigated. To monitor the formation of pegylated and non-pegylated multilayer films, adsorption of the following proteins: HSA, Fibrinogen, and FBS were measured by quartz crystal microbalance (QCM - D). We found that protein adsorption onto all pegylated polyelectrolyte multilayers was significantly reduced in comparison to non-pegylated ones. Long-term performance tests confirmed the stability and the durability of the protein resistant properties of the pegylated multilayers. Antiadhesive properties of tested surfaces pegylated by PGA-g-PEG were compared to the available data for pegylated polycation PLL-g-PEG.

Hollow polymer nanocapsules: synthesis, properties, and applications

Hollow polymer nanocapsules (HPNs) have gained tremendous interest in recent years due to their numerous desirable properties compared to their solid counterparts.

The Relationship between the Mechanism of Zinc Oxide Crystallization and Its Antimicrobial Properties for the Surface Modification of Surgical Meshes

Surgical meshes were modified with zinc oxide (ZnO) using a chemical bath deposition method (CBD) at 50 °C, 70 °C, or 90 °C, in order to biologically activate them. Scanning electron microscopy (SEM), mass changes, and X-ray diffraction measurements revealed that at low temperatures Zn(OH)₂ was formed, and that this was converted into ZnO with a temperature increase. The antimicrobial activity without light stimulation of the ZnO modified Mersilene™ meshes was related to the species of microorganism, the incubation time, and the conditions of the experiment. Generally, cocci (S. aureus, S. epidermidis) and yeast (C. albicans) were more sensitive than Gram-negative rods (E. coli). The differences in sensitivity of the studied microorganisms to ZnO were discussed. The most active sample was that obtained at 90 °C. The mechanism of antimicrobial action of ZnO was determined by various techniques, such as zeta potential analysis, electron paramagnetic resonance (EPR) spectroscopy, SEM studies, and measurements of Zn(II) and reactive oxygen species (ROS) concentration. Our results confirmed that the generation of free radicals was crucial, which occurs on the surface of crystalline ZnO.

IR780-loaded TPGS-TOS micelles for breast cancer photodynamic therapy

IR780 iodide is a near-infrared (NIR) dye with a huge potential for cancer imaging and phototherapy. However, its biomedical application is strongly impaired by its lipophilic character. Herein, amphiphilic micelles based on d-α-tocopheryl polyethylene glycol succinate (TPGS) and d-α-tocopheryl succinate (TOS), two vitamin E derivatives with intrinsic anticancer activity, are explored to load IR780. IR780-loaded micelles with suitable sizes are obtained by using specific TPGS and TOS weight feed ratios during micelles formulation and these are able to encapsulate IR780 with high efficiency. In in vitro assays, the IR780-loaded micelles induce a cytotoxic effect in cancer cells upon exposure to NIR irradiation through the generation of reactive oxygen species (photodynamic therapy). This effective ablation of cancer cells is achieved using an ultra-low IR780 concentration. Moreover, IR780-loaded micelles also have the ability to act as photothermal and imaging agents, which widens their therapeutic and diagnostic potential. Overall, TPGS-TOS micelles are promising nanoplatforms for IR780-mediated cancer phototherapy and imaging.

Method Validation for Progesterone Determination in Poly(methyl methacrylate) Nanoparticles Synthesized via Miniemulsion Polymerization

Exogenous progesterone has several applications in human health and in veterinary medicine, especially in fixed-time artificial insemination protocol. Progesterone nanoencapsulation in biocompatible polymers, such as poly(methyl methacrylate) (PMMA), is an alternative to substitute silicone-based release device traditionally used for estrus control. Progesterone concentration inside the nanoparticles must be precisely known; for that reason, a validation methodology must be applied to ensure reliable results, suitable for nanoparticles application. In this work, an UV-Vis spectrophotometric method was validated for the determination of progesterone in PMMA nanoparticles synthesized by miniemulsion polymerization. Chloroform was used as solvent, showing selectivity to the encapsulated drug and the components of the polymeric matrix did not influence progesterone recovery. Detection and quantitation limits (DL and QL) obtained were 0.32 and 0.96 mg·L−1, respectively, and precision tests (between different analysts and equipment) indicated acceptable Relative Standard Deviations (RSD < 5%). Miniemulsion polymerization reactions were carried out producing two different morphologies: nanospheres (NS) and nanocapsules (NC), with average intensity diameters (Dz) of 150–200 nm and 240–300 nm, respectively. Polymerization gravimetric conversions obtained for both cases were higher than 95% and encapsulation efficiencies greater than 69% and 90% for the nanospheres and nanocapsules, respectively.

Location of Varying Hydrophobicity Zinc(II) Phthalocyanine-Type Photosensitizers in Methoxy Poly(ethylene oxide) and Poly(l-lactide) Block Copolymer Micelles Using 1H NMR and XPS Techniques

Hydrophobic zinc(II) phthalocyanine-type derivatives, solubilized in polymeric micelles (PMs), provide a befitting group of so-called nanophotosensitizers, suitable for a variety of photodynamic therapy (PDT) protocols. The factors that influence the success of such products in PDT are the location of the active cargo in the PMs and the nanocarrier-enhanced ability to safely interact with biological systems and fulfill their therapeutic functions. Therefore, the aim of this work was to determine the solubilization loci of three phthalocyanines of varying hydrophobicity, i.e., zinc(II) phthalocyanine (ZnPc), along with its tetrasulfonic acid (ZnPc-sulfo₄) and perfluorinated (ZnPcF₁₆) derivatives, loaded in polymeric micelles of methoxy poly(ethylene oxide)-b-poly(l-lactide) (mPEG-b-PLLA), by means of ¹H nuclear magnetic resonance (NMR) and X-ray photoelectron spectroscopy (XPS) combined with ion sputtering. Furthermore, the microenvironment influence upon the chemical and physical status of the solubilized cargo in PMs, expressed by photobleaching and reactive oxygen species (ROS) generation comparing to the same properties of native cargoes in solution, was also evaluated and discussed in regards to the probing location data. The studied phthalocyanine-loaded PMs exhibited good physical stability, high drug-loading efficiency, and a size of less than ca. 150 nm with low polydispersity indices. The formation of polymeric micelles and the solubilization locus were investigated by ¹H NMR and XPS. ZnPc localized within the PM core, whereas both ZnPcF₁₆ and ZnPc-sulfo₄ - in the corona of PMs. We proved that the cargo locus is crucial for the photochemical properties of the studied phthalocyanines; the increase in photostability and ability to generate ROS in micellar solution compared to free photosensitizer was most significant for the photosensitizer in the PM core. Our results indicate the role of the cargo location in the PM microenvironment and demonstrate that such attempts are fundamental for improving the properties of photosensitizers and their assumed efficiency as nanophotosensitizers in PDT.

The effect of anionic dicephalic surfactants on fabrication of varied-core nanocarriers for sustained release of porphyrin photosensitizers

Double-headed anionic surfactants could provide a profound group of efficient stabilizers of new template-mediated nanocarriers for effective encapsulation and sustained release of highly hydrophobic photosensitizers, and therefore their improved therapeutic activity in photodynamic therapy (PDT) protocols. We have thus encapsulated porphyrin-origin dyes, i.e., verteporfin (VP) and meso-tetraphenylporphyrin (TPP) in different types of sodium alkyliminobisacetates, C_n(COONa)₂-stabilized nanosystems including biocompatible poly(l-glutamic acid)/poly(l-lysine) - PGA/PLL, multilayer nanocapsules (NCs). The latter were prepared via a layer-by-layer (LbL) approach with either solid (nanoprecipitated), or liquid (nanoemulsion-templated) oil core while zeta potential measurements enabled to evaluate progress of the polyelectrolytes LbL deposition on both cores and the NCs' stability. Backscattering profiles (BS) confirmed the long-lasting stability of the optimized nanosystems, which size (<200nm), polidyspersity and morphology were examined by dynamic light scattering (DLS) and atomic force microscopy (AFM) techniques. Our studies indicated that the encapsulation of VP and TPP in the both type of multilayer NCs increases their solubility in aqueous solution and protects them from the surrounding medium. Mainly, it reduces the photobleaching rate of these porphyrin-type photosensitizers and improves their photochemical properties during irradiation in regards to the free (non-encapsulated) molecules. As far as the core-type is considered, both nanoemulsion-loaded porphyrins, photobleached ca. 15-20% faster than the solid nanoparticle analogs. By using 9,10-anthracenediyl-bis(methylene)dimalonic acid (ABMDMA) as a singlet oxygen (¹O₂) scavenger molecule, the enhanced generation of reactive species was evaluated for the both encapsulated photosensitizers in comparison to their native form. In vitro sustained release under physiological conditions or in the presence of human serum albumin (HSA) was achieved in favor of the solid core NCs for VP and TPP. The designed NCs - offering better chemical and physical stability, high loading capacity for the cargo and ability to release it in a controlled and continuous manner - can be considered as efficacious nanocarriers for PDT.

Versatile Route to Colloidal Stability and Surface Functionalization of Hydrophobic Nanomaterials

We introduce a general method for the stabilization and surface functionalization of hydrophobic nanoparticles using an amphiphilic copolymer, poly(maleic anhydride-alt-1-octadecene)-poly(ethylene glycol) methacrylate (PMAO-PEGMA). Coating nanoparticles with PMAO-PEGMA results in colloidally stable nanoparticles decorated with reactive carboxylic acid and methacrylate functionalities, providing a versatile platform for chemical reactions. The versatility and ease of surface functionalization is demonstrated by varying both the core material and the chemistry used. Specifically, the carboxylic acid functionalities are used to conjugate wheat germ agglutinin to conducting polymer nanoparticles via carbodiimide-mediated coupling, and the methacrylate groups are used to link cysteamine to the surface of poly(ε-caprolactone) nanoparticles via thiol-ene click chemistry and to link temperature-responsive polymer shells to the surface of gold nanoparticles via free radical polymerization.

Encapsulation of clozapine in polymeric nanocapsules and its biological effects

Clozapine is an effective atypical antipsychotic drug that unfortunately exhibits poor oral bioavailability. Moreover, the clinical use of the compound is limited because of its numerous unfavorable and unsafe side effects. Therefore, the aim of the present study was the development of a new nanocarrier for a more effective clozapine delivery. Here, clozapine was encapsulated into polymeric nanocapsules (NCs). Polyelectrolyte multilayer shells were constructed by the technique of sequential adsorption of polyelectrolytes (LbL) using biocompatible polyanion PGA (Poly-L-glutamic acid, sodium salt) and polycation PLL (poly-L-lysine) on clozapine-loaded nanoemulsion cores. Pegylated external layers were prepared using PGA-g-PEG (PGA grafted by PEG (polyethylene glycol)). Clozapine was successfully loaded into the PLL-PGA nanocarriers (CLO-NCs) with an average size of 100 nm. In vitro analysis of the interactions of the CLO-NCs with the cells of the mononuclear phagocytic system (MPS) was conducted. Cell biocompatibility, phagocytosis potential, and cellular uptake were studied. Additionally, the biodistribution and behavioral effects of the encapsulated clozapine were also studied. The results indicate that surface modified (by PEG grafting) polymeric PLL-PGA CLO-NCs are very promising nanovehicles for improving clozapine delivery.

Microfluidic platform for photodynamic therapy cytotoxicity analysis of nanoencapsulated indocyanine-type photosensitizers

The application of nanotechnology is important to improve research and development of alternative anticancer therapies. In order to accelerate research related to cancer diagnosis and to improve the effectiveness of cancer treatment, various nanomaterials are being tested. The main objective of this work was basic research focused on examination of the mechanism and effectiveness of the introduction of nanoencapsulated photosensitizers to human carcinoma (A549) and normal cells (MRC-5). Newly encapsulated hydrophobic indocyanine-type photosensitizer (i.e., IR-780) was subjected to in vitro studies to determine its release characteristics on a molecular level. The photosensitizers were delivered to carcinoma and normal cells cultured under model conditions using multiwell plates and with the use of the specially designed hybrid (poly(dimethylsiloxane) (PDMS)/glass) microfluidic system. The specific geometry of our microsystem allows for the examination of intercellular interactions between cells cultured in the microchambers connected with microchannels of precisely defined length. Our microsystem allows investigating various therapeutic procedures (e.g., photodynamic therapy) on monoculture, coculture, and mixed culture, simultaneously, which is very difficult to perform using standard multiwell plates. In addition, we tested the cellular internalization of nanoparticles (differing in size, surface properties) in carcinoma and normal lung cells. We proved that cellular uptake of nanocapsules loaded with cyanine IR-780 in carcinoma cells was more significant than in normal cells. We demonstrated non cytotoxic effect of newly synthesized nanocapsules built with polyelectrolytes (PEs) of opposite surface charges: polyanion-polysodium-4-styrenesulphonate and polycation-poly(diallyldimethyl-ammonium) chloride loaded with cyanine IR-780 on human lung carcinoma and normal cell lines. However, the differences observed in the photocytotoxic effect between two types of tested nanocapsules can result from the type of last PE layer and their different surface charge.

New acrylate terpolymer-based nanoparticles for the release of nucleic acid: a preliminary study

PURPOSE

Nano-drug delivery systems based on polymeric biomaterials have received considerable interest as drug delivery vehicles. In this work, radical polymerization was carried out in order to obtain nanoparticles based on a new acrylate terpolymer (PBMA-(PEG)MEMA-PDMAEMA).

METHODS

Nanoparticles were developed in the form both of nanospheres and nanocapsules, an innovative kind of hollow nanoparticles with a great potential because of their low effective density and high specific surface area. The ability of the nanoparticles to load and then release a nucleic acid (DNA) to be used in cancer treatment was also investigated.

RESULTS

Scanning electron microscopy analysis showed a spherical shape, nanometric dimensions, and a homogeneous distribution of the nanoparticles, also confirmed by dynamic light scattering measurements. Fourier-transform infrared spectroscopy chemical imaging analysis carried out on the nanocapsules before and after removal of the core demonstrated the presence of the cavity. High-performance liquid chromatography analysis confirmed good encapsulation efficiency of DNA both for nanospheres and nanocapsules. Drug release tests showed controlled release kinetics for both the systems with a high release of DNA in the first hours. In vitro MTT assay showed that the particles do not have cytotoxic effects on the cells.

CONCLUSIONS

The preliminary investigation showed that the terpolymer-based nanoparticles developed in this study could be good candidates to be used as innovative and versatile gene delivery systems.