A new preparation strategy for surface modified PLA nanoparticles to enhance uptake by endothelial cells

Self-Lubricating, Living Contact Lenses

The increasing prevalence of dry eye syndrome in aging and digital societies compromises long-term contact lens (CL) wear and forces users to regular eye drop instillation to alleviate discomfort. Here a novel approach with the potential to improve and extend the lubrication properties of CLs is presented. This is achieved by embedding lubricant-secreting biofactories within the CL material. The self-replenishable reservoirs autonomously produce and release hyaluronic acid (HA), a natural lubrication and wetting agent, long term. The hydrogel matrix regulates the growth of the biofactories and the HA production, and allows the diffusion of nutrients and HA for at least 3 weeks. The continuous release of HA sustainably reduces the friction coefficient of the CL surface. A self-lubricating CL prototype is presented, where the functional biofactories are contained in a functional ring at the lens periphery, outside of the vision area. The device is cytocompatible and fulfils physicochemical requirements of commercial CLs. The fabrication process is compatible with current manufacturing processes of CLs for vision correction. It is envisioned that the durable-by-design approach in living CL could enable long-term wear comfort for CL users and minimize the need for lubricating eye drops.

In vitro evaluation of physicochemical-dependent effects of polymeric nanoparticles on their cellular uptake and co-localization using pulmonary calu-3 cell lines

OBJECTIVE

The study evaluated physicochemical properties of eight different polymeric nanoparticles (NPs) and their interaction with lung barrier and their suitability for pulmonary drug delivery.

METHODS

Eight physiochemically different NPs were fabricated from Poly lactic-co-glycolic acid (PLGA, PL) and Poly glycerol adipate-co-ω-pentadecalactone (PGA-co-PDL, PG) via emulsification-solvent evaporation. Pulmonary barrier integrity was investigated in vitro using Calu-3 under air-liquid interface. NPs internalization was investigated using a group of pharmacological inhibitors with subsequent microscopic visual confirmation.

RESULTS

Eight NPs were successfully formulated from two polymers using emulsion-solvent evaporation; 200, 500 and 800 nm, negatively-charged and positively-charged. All different NPs did not alter tight junctions and PG NPs showed similar behavior to PL NPs, indicating its suitability for pulmonary drug delivery. Active endocytosis uptake mechanisms with physicochemical dependent manner were observed. In addition, NPs internalization and co-localization with lysosomes were visually confirmed indicating their vesicular transport.

CONCLUSION

PG and PL NPs had shown no or low harmful effects on the barrier integrity, and with effective internalization and vesicular transport, thus, prospectively can be designed for pulmonary delivery applications.

Polyvinyl Alcohol (PVA)-Based Nanoniosome for Enhanced in vitro Delivery and Anticancer Activity of Thymol

Introduction

There is an unmet need to develop potent therapeutics against cancer with minimal side effects and systemic toxicity. Thymol (TH) is an herbal medicine with anti-cancer properties that has been investigated scientifically. This study shows that TH induces apoptosis in cancerous cell lines such as MCF-7, AGS, and HepG2. Furthermore, this study reveals that TH can be encapsulated in a Polyvinyl alcohol (PVA)-coated niosome (Nio-TH/PVA) to enhance its stability and enable its controlled release as a model drug in the cancerous region.

Materials and Methods

TH-loaded niosome (Nio-TH) was fabricated and optimized using Box-Behnken method and the size, polydispersity index (PDI) and entrapment efficiency (EE) were characterized by employing DLS, TEM and SEM, respectively. Additionally, in vitro drug release and kinetic studies were performed. Cytotoxicity, antiproliferative activity, and the mechanism were assessed by MTT assay, quantitative real-time PCR, flow cytometry, cell cycle, caspase activity evaluation, reactive oxygen species investigation, and cell migration assays.

Results

This study demonstrated the exceptional stability of Nio-TH/PVA at 4 °C for two months and its pH-dependent release profile. It also showed its high toxicity on cancerous cell lines and high compatibility with HFF cells. It revealed the modulation of Caspase-3/Caspase-9, MMP-2/MMP-9 and Cyclin D/ Cyclin E genes by Nio-TH/PVA on the studied cell lines. It confirmed the induction of apoptosis by Nio-TH/PVA in flow cytometry, caspase activity, ROS level, and DAPI staining assays. It also verified the inhibition of metastasis by Nio-TH/PVA in migration assays.

Conclusion

Overall, the results of this study revealed that Nio-TH/PVA may effectively transport hydrophobic drugs to cancer cells with a controlled-release profile to induce apoptosis while exhibiting no detectable side effects due to their biocompatibility with normal cells.

Advances in Functionalization of Bioresorbable Nanomembranes and Nanoparticles for Their Use in Biomedicine

Bioresorbable nanomembranes (NMs) and nanoparticles (NPs) are powerful polymeric materials playing an important role in biomedicine, as they can effectively reduce infections and inflammatory clinical patient conditions due to their high biocompatibility, ability to physically interact with biomolecules, large surface area, and low toxicity. In this review, the most common bioabsorbable materials such as those belonging to natural polymers and proteins for the manufacture of NMs and NPs are reviewed. In addition to biocompatibility and bioresorption, current methodology on surface functionalization is also revisited and the most recent applications are highlighted. Considering the most recent use in the field of biosensors, tethered lipid bilayers, drug delivery, wound dressing, skin regeneration, targeted chemotherapy and imaging/diagnostics, functionalized NMs and NPs have become one of the main pillars of modern biomedical applications.

Monobody adapter for functional antibody display on nanoparticles for adaptable targeted delivery applications

Vascular endothelial cells (ECs) play a central role in the pathophysiology of many diseases. The use of targeted nanoparticles (NPs) to deliver therapeutics to ECs could dramatically improve efficacy by providing elevated and sustained intracellular drug levels. However, achieving sufficient levels of NP targeting in human settings remains elusive. Here, we overcome this barrier by engineering a monobody adapter that presents antibodies on the NP surface in a manner that fully preserves their antigen-binding function. This system improves targeting efficacy in cultured ECs under flow by >1000-fold over conventional antibody immobilization using amine coupling and enables robust delivery of NPs to the ECs of human kidneys undergoing ex vivo perfusion, a clinical setting used for organ transplant. Our monobody adapter also enables a simple plug-and-play capacity that facilitates the evaluation of a diverse array of targeted NPs. This technology has the potential to simplify and possibly accelerate both the development and clinical translation of EC-targeted nanomedicines.

Bruch's-Mimetic Nanofibrous Membranes Functionalized with the Integrin-Binding Peptides as a Promising Approach for Human Retinal Pigment Epithelium Cell Transplantation

Background: This study aimed to develop an ultrathin nanofibrous membrane able to, firstly, mimic the natural fibrous architecture of human Bruch’s membrane (BM) and, secondly, promote survival of retinal pigment epithelial (RPE) cells after surface functionalization of fibrous membranes. Methods: Integrin-binding peptides (IBPs) that specifically interact with appropriate adhesion receptors on RPEs were immobilized on Bruch’s-mimetic membranes to promote coverage of RPEs. Surface morphologies, Fourier-transform infrared spectroscopy spectra, contact angle analysis, Alamar Blue assay, live/dead assay, immunofluorescence staining, and scanning electron microscopy were used to evaluate the outcome. Results: Results showed that coated membranes maintained the original morphology of nanofibers. After coating with IBPs, the water contact angle of the membrane surfaces varied from 92.38 ± 0.67 degrees to 20.16 ± 0.81 degrees. RPE cells seeded on IBP-coated membranes showed the highest viability at all time points (Day 1, p < 0.05; Day 3, p < 0.01; Days 7 and 14, p < 0.001). The proliferation rate of RPE cells on uncoated poly(ε-caprolactone) (PCL) membranes was significantly lower than that of IBP-coated membranes (p < 0.001). SEM images showed a well-organized hexa/polygonal monolayer of RPE cells on IBP-coated membranes. RPE cells proliferated rapidly, contacted, and became confluent. RPE cells formed a tight adhesion with nanofibers under high-magnification SEM. Our findings confirmed that the IBP-coated PCL membrane improved the attachment, proliferation, and viability of RPE cells. In addition, in this study, we used serum-free culture for RPE cells and short IBPs without immunogenicity to prevent graft rejection and immunogenicity during transplantation. Conclusions: These results indicated that the biomimic BM-IBP-RPE nanofibrous graft might be a new, practicable approach to increase the success rate of RPE cell transplantation.

Chitosan modified squalene nanostructured lipid carriers as a promising adjuvant for freeze-dried ovalbumin vaccine

As immune adjuvants assisting vaccines, nanoparticle delivery systems have been widely exploited. Squalene, the major ingredient of approved adjuvant MF59, has great potential in activating immune responses. In the current study, model antigen ovalbumin (OVA) was encapsulated into squalene-based nanostructured lipid carriers (NLCs), and the chitosan, a cationic polysaccharide, was used for modifying nanoparticles to develop a functionalized and cationic nanoparticle delivery system (OVA-csNLCs). Firstly, the optimal formulation of csNLCs was successfully screened out, and had hydrodynamic diameter of 235.80 ± 5.99 nm and zeta potential of 34.90 ± 6.95 mV. Then, the generated OVA-csNLCs had no significant difference in hydrodynamic diameter and exhibited lower zeta potential of 19.03 ± 0.31 mV and high encapsulation efficiency of 83.4%. Sucrose (10%, w/w) was selected as optimal lyoprotectant, exhibiting good stability of OVA-csNLCs in the form of freeze-dried powder. More importantly, the OVA-csNLCs effectively promoted OVA antigen uptake by macrophage, significantly enhanced the level of OVA-specific IgG, and induced a Th2-based immune response in vivo. Furthermore, mice immunization experiment demonstrated that OVA-csNLCs had well biocompatibility and facilitated spleen lymphocytes proliferation. Above findings indicate that chitosan modified squalene nanostructured lipid carriers show promise as antigen delivery system and an open adjuvant platform.

From adsorption to covalent bonding: Apolipoprotein E functionalization of polymeric nanoparticles for drug delivery across the blood-brain barrier

The blood-brain barrier (BBB) is composed of brain endothelial cells, pericytes, and astrocytes, which build a tight cellular barrier. Therapeutic (macro)molecules are not able to transit through the BBB in their free form. This limitation is bypassed by apolipoprotein E (ApoE)-functionalized polymeric nanoparticles (NPs) that are able to transport drugs (e.g. dalargin, loperamide, doxorubicin, nerve growth factor) across the BBB via low density lipoprotein (LDL) receptor mediated transcytosis. Coating with polysorbate 80 or poloxamer 188 facilitates ApoE adsorption onto polymeric NPs enabling recognition by LDL receptors of brain endothelial cells. This effect is even enhanced when NPs are directly coated with ApoE without surfactant anchor. Similarly, covalent coupling of ApoE to NPs that bear reactive groups on their surface leads to significantly improved brain uptake while avoiding the use of surfactants. Several in vitro BBB models using brain endothelial cells or co-cultures with astrocytes/pericytes/glioma cells are described which provide first insights regarding the ability of a drug delivery system to cross this barrier. In vivo models are employed to simulate central nervous system-relevant diseases such as Alzheimer's or Parkinson's disease and cerebral cancer.

Nano, micro particulate and cosmetic delivery systems of polylactic acid: A mini review

BACKGROUND

Poly lactic acid and its copolymers are considered to be the preferred substrates for drug delivery devices. Poly lactic acid is a biocompatible, biodegradable and nontoxic polymer. It was approved by Food and Drug Administration and thought to be among the most attractive polymeric candidates intended for controlling drug delivery. It was utilized for the development of devices for the delivery of small molecules, proteins, genes, vaccines, anticancer drugs, and macromolecules.

OBJECTIVES AND METHODS

This manuscript lists the different techniques for synthesizing poly lactic acid-based nano and microparticles such as emulsion-based methods, precipitation-based methods, direct compositing methods, in situ forming micro-particles, and microfluidic technique.

CONCLUSIONS

In addition, it describes the application and use of poly lactic acid in biomedical and cosmetic delivery systems.

Self-assembly and intracellular delivery of DNA by a truncated fragment derived from the Trojan peptide Penetratin

Penetratin is a short Trojan peptide that attracts great interest in biomedical research for its capacity to translocate biological membranes. Herein, we study in detail both self-assembly and intracellular delivery of DNA by the heptamer KIWFQNR, a truncated peptide derived from Penetratin. This shortened sequence possesses a unique design with bolaamphiphilic characteristics that preserves the longest noncationic amino acid portion found in Penetratin. These features convey amphipathicity to assist self-assembly and make it a suitable model for exploring the role of hydrophobic residues for peptide interaction and cell uptake. We show that the fragment forms peptiplexes (i.e., peptide-DNA complexes), and aggregates into long nanofibers with clear β-sheet signature. The supramolecular structure of nanofibers is likely composed of DNA cores surrounded by a peptide shell to which the double helix behaves as a template and induces fibrillization. A nucleation and growth mechanism proceeding through liquid-liquid phase separation of coacervates is proposed for describing the self-assembly of peptiplexes. We also demonstrate that peptiplexes deliver double-stranded 200 bp DNA into HeLa cells, indicating its potential for preparing non-viral vectors for oligonucleotides through noncovalent strategies. Since the main structural features of native Penetratin are conserved in this simpler fragment, our findings also highlight the role of uncharged amino acids for structuration, and thus for the ability of Penetratin to cross cell membranes.

A Perspective on Polylactic Acid-Based Polymers Use for Nanoparticles Synthesis and Applications

Polylactic acid (PLA)-based polymers are ubiquitous in the biomedical field thanks to their combination of attractive peculiarities: biocompatibility (degradation products do not elicit critical responses and are easily metabolized by the body), hydrolytic degradation in situ, tailorable properties, and well-established processing technologies. This led to the development of several applications, such as bone fixation screws, bioresorbable suture threads, and stent coating, just to name a few. Nanomedicine could not be unconcerned by PLA-based materials as well, where their use for the synthesis of nanocarriers for the targeted delivery of hydrophobic drugs emerged as a new promising application. The purpose of the here presented review is two-fold: on one side, it aims at providing a broad overview of PLA-based materials and their properties, which allow them gaining a leading role in the biomedical field; on the other side, it offers a specific focus on their recent use in nanomedicine, highlighting opportunities and perspectives.

Preparation of Sesquiterpene Lactone-Loaded PLA Nanoparticles and Evaluation of Their Antitrypanosomal Activity

Human African trypanosomiasis (HAT), also commonly known as sleeping sickness, is a neglected tropical disease affecting millions of people in poorly developed regions in sub-Saharan Africa. There is no satisfactory treatment for this infection. The investment necessary to bring new drugs to the market is a big deterrent to drug development, considering that the affected communities form a non-lucrative sector. However, natural products and many sesquiterpene lactones (STLs) in particular are very strong trypanocides. Research and applications of nano-drug delivery systems such as nanoparticles (NPs) have undergone unprecedented growth in the recent past. This is mainly due to the advantages offered by these systems, such as targeted delivery of the drug to the place of action (cell, parasite, etc), sustained release of the drug, increased bioavailability, reduced drug dosage, and reduction of undesired side effects, among others. In this study, the STLs α-santonin, arglabin, schkuhrin II, vernolepin, and eucannabinolide, all trypanocides, were loaded into polylactic acid (PLA) NPs through an emulsification-diffusion method. The NPs were stable, homogenous, and spherical in shape with a rounded knotty depression like a navel orange. The average particle sizes were 202.3, 220.3, 219.5, 216.9, and 226.4 nm for α-santonin, arglabin, schkuhrin II, vernolepin, and eucannabinolide, respectively. The NPs had encapsulation efficiencies of 94.6, 78.1, 76.8, 60.7, and 78.9% for α-santonin, arglabin, schkuhrin II, vernolepin, and eucannabinolide, respectively. The NPs loaded with arglabin, vernolepin, and eucannabinolide exhibited considerable antitrypanosomal activity against Trypanosoma brucei rhodesiense (Tbr) with free drug equivalent IC₅₀ values of 3.67, 1.11 and 3.32 µM, respectively. None of the NP formulations displayed cytotoxicity towards mammalian cells (rat skeletal myoblast cell line L6). These results provide new insights into the possibility of incorporating STLs into nanoparticles, which may provide new options for their formulation in order to develop new drugs against HAT.

Enhanced Permeation of Methotrexate via Loading into Ultra-permeable Niosomal Vesicles: Fabrication, Statistical Optimization, Ex Vivo Studies, and In Vivo Skin Deposition and Tolerability

The aim of this study was to incorporate methotrexate (MTX) into ultra-permeable niosomal vesicles, containing cremophor RH40 as an edge activator (EA) and polyvinyl alcohol (PVA) as a stabilizer to enhance the drug permeation. Formulae were prepared by ethanol injection method following a Box-Behnken design in order to optimize the formulation variables (EA%, stabilizer %, and sonication time). To investigate the role of both cremophor RH40 and PVA, conventional MTX niosomes and MTX niosomes containing PVA only were fabricated. Drug entrapment efficiency percent (EE%), particle size (PS) analysis, zeta potential (ZP) measurements, and transmission electron microscopy (TEM) were conducted to characterize the vesicles. Cell viability studies and ex vivo permeation experiments of the optimized formula were conducted. Lastly, in vivo skin deposition of MTX from both the optimized formula and MTX solution was performed in rats. Besides, histopathological changes in rat skin were assessed. The optimized MTX ultra-permeable niosomal formula demonstrated spherical morphology, with an EE% of 65.16% and a PS of 453.6 nm. The optimized formula showed better physical stability in comparison with that of the same composition but lacking PVA. The cell viability studies verified the superior cytotoxicity of the optimized formula, and the ex vivo permeation studies revealed its ability to improve the drug permeation. The optimized formula demonstrated a significant deposition of MTX in rat dorsal skin, and histopathological evaluation confirmed the tolerability of the optimized formula in rats upon topical application. Accordingly, ultra-permeable noisomes, as a stable nanosystem, could be promising for effective delivery of MTX.

Serum type and concentration both affect the protein-corona composition of PLGA nanoparticles

Background: When nanoparticles (NPs) are applied into a biological fluid, such as blood, proteins bind rapidly to their surface forming a so-called "protein corona". These proteins are strongly attached to the NP surface and confers them a new biological identity that is crucial for the biological response in terms of body biodistribution, cellular uptake, and toxicity. The corona is dynamic in nature and it is well known that the composition varies in dependence of the physicochemical properties of the NPs. In the present study we investigated the protein corona that forms around poly(lactide-co-glycolide) (PLGA) NPs at different serum concentrations using two substantially different serum types, namely fetal bovine serum (FBS) and human serum. The corona was characterized by means of sodium dodecylsulfate polyacrylamide gel electrophoresis (SDS-PAGE), Bradford protein assay, zeta potential measurements, and liquid chromatography-mass spectrometry/mass spectrometry (LC-MS/MS). Additionally, the time-dependent cell interaction of PLGA NPs in the absence or presence of a preformed protein corona was assessed by in vitro incubation experiments with the human liver cancer cell line HepG2. Results: Our data revealed that the physiological environment critically affects the protein adsorption on PLGA NPs with significant impact on the NP-cell interaction. Under comparable conditions the protein amount forming the protein corona depends on the serum type used and the serum concentration. On PLGA NPs incubated with either FBS or human serum a clear difference in qualitative corona protein composition was identified by SDS-PAGE and LC-MS/MS in combination with bioinformatic protein classification. In the case of human serum a considerable change in corona composition was observed leading to a concentration-dependent desorption of abundant proteins in conjunction with an adsorption of high-affinity proteins with lower abundance. Cell incubation experiments revealed that the respective corona composition showed significant influence on the resulting nanoparticle-cell interaction. Conclusion: Controlling protein corona formation is still a challenging task and our data highlight the need for a rational future experimental design in order to enable a prediction of the corona formation on nanoparticle surfaces and, therefore, the resulting biodistribution in the body.