PLGA-based nanoparticles: A new paradigm in biomedical applications

Poly(lactic-co-glycolic) Acid (PLGA) Nanoparticles and Transdermal Drug Delivery: An Overview

BACKGROUND

Biodegradable polymeric nanoparticles have garnered pharmaceutical industry attention throughout the past decade. PLGA [Poly(lactic-co-glycolic acid)] is an excellent biodegradable polymer explored for the preparation of nanoparticles that are administered through various routes like intravenous and transdermal. PLGA's versatility makes it a good choice for the preparation of nanoparticles.

OBJECTIVE

The main objective of this review paper was to summarize methods of preparation and characterization of PLGA nanoparticles along with their role in the transdermal delivery of various therapeutic agents.

METHODS

A literature survey for the present review paper was done using various search engines like Pubmed, Google Scholar, and Science Direct.

RESULTS

In comparison to traditional transdermal administration systems, PLGA nanoparticles have demonstrated several benefits in preclinical investigations, including fewer side effects, low dosage frequency, high skin permeability, and simplicity of application.

CONCLUSION

PLGA nanoparticles can be considered efficient nanocarriers for the transdermal delivery of drugs. Nevertheless, the clinical investigation of PLGA nanoparticles for the transdermal administration of therapeutic agents remains a formidable obstacle.

Diclofenac Loaded Biodegradable Nanoparticles as Antitumoral and Antiangiogenic Therapy

Cancer is identified as one of the main causes of death worldwide, and an effective treatment that can reduce/eliminate serious adverse effects is still an unmet medical need. Diclofenac, a non-steroidal anti-inflammatory drug (NSAID), has demonstrated promising antitumoral properties. However, the prolonged use of this NSAID poses several adverse effects. These can be overcome by the use of suitable delivery systems that are able to provide a controlled delivery of the payload. In this study, Diclofenac was incorporated into biodegradable polymeric nanoparticles based on PLGA and the formulation was optimized using a factorial design approach. A monodisperse nanoparticle population was obtained with a mean size of ca. 150 nm and negative surface charge. The release profile of diclofenac from the optimal formulation followed a prolonged release kinetics. Diclofenac nanoparticles demonstrated antitumoral and antiangiogenic properties without causing cytotoxicity to non-tumoral cells, and can be pointed out as a safe, promising and innovative nanoparticle-based formulation with potential antitumoral effects.

Polymer nanocarriers for targeted local delivery of agents in treating brain tumors

Glioblastoma (GBM), the deadliest brain cancer, presents a multitude of challenges to the development of new therapies. The standard of care has only changed marginally in the past 17 years, and few new chemotherapies have emerged to supplant or effectively combine with temozolomide. Concurrently, new technologies and techniques are being investigated to overcome the pharmacokinetic challenges associated with brain delivery, such as the blood brain barrier (BBB), tissue penetration, diffusion, and clearance in order to allow for potent agents to successful engage in tumor killing. Alternative delivery modalities such as focused ultrasound and convection enhanced delivery allow for the local disruption of the BBB, and the latter in particular has shown promise in achieving broad distribution of agents in the brain. Furthermore, the development of polymeric nanocarriers to encapsulate a variety of cargo, including small molecules, proteins, and nucleic acids, have allowed for formulations that protect and control the release of said cargo to extend its half-life. The combination of local delivery and nanocarriers presents an exciting opportunity to address the limitations of current chemotherapies for GBM toward the goal of improving safety and efficacy of treatment. However, much work remains to establish standard criteria for selection and implementation of these modalities before they can be widely implemented in the clinic. Ultimately, engineering principles and nanotechnology have opened the door to a new wave of research that may soon advance the stagnant state of GBM treatment development.

Polymeric nanoparticles targeting Sialyl-Tn in gastric cancer: A live tracking under flow conditions

Drug delivery using nanoparticles (NPs) represents a potential approach for therapy in cancer, such gastric cancer (GC) due to their targeting ability and controlled release properties. The use of advanced nanosystems that deliver anti-cancer drugs specifically to tumor cells may strongly rely on the expression of cancer-associated targets. Glycans aberrantly expressed by cancer cells are attractive targets for such delivery strategy. Sialylated glycans, such as Sialyl-Tn (STn) are aberrantly expressed in several epithelial tumors, including GC, being a potential target for a delivery nanosystem. The aim of this study was the development of NPs surface-functionalized with a specific antibody targeting the STn glycan and further evaluate this nanosystem effectiveness regarding its specificity and recognition capacity. Our results showed that the NPs surface-functionalized with anti-STn antibody efficiently are recognized by cells displaying the cancer-associated STn antigen under static and live cell monitoring flow conditions. This uncovers the potential use of such NPs for drug delivery in cancer. However, flow exposure was disclosed as an important biomechanical parameter to be taken into consideration. Here we presented an innovative and successful methodology to live track the NPs targeting STn antigen under shear stress, simulating the physiological flow. We demonstrate that unspecific binding of NPs agglomerates did not occur under flow conditions, in contrast with static assays. This robust approach can be applied for in vitro drug studies, giving valuable insights for in vivo studies.

Synthesis, physicochemical characterization, and in vitro evaluation of biodegradable PLGA nanoparticles entrapped to folic acid for targeted delivery of kaempferitrin

Polymeric nanoparticles are widely studied in the treatment of colorectal cancer. Kaempferitrin-loaded nontoxic and biodegradable poly(d,l-lactic-co-glycolic acid) (PLGA) nanoparticles (NPs) developed by the solvent emulsion evaporation method by improving its solubility and bioavailability. In order to improve the delivery of kaempferitrin (KM) to cancerous cells, folic acid (FA) combined kaempfertrin PLGA NPs were prepared. The goal of the study was whether PLGA NPs with surface KM and FA could help to prevent colorectal cancer. The synthesis of KM with FA in a nanomedicine could be crucial in the development of colon cancer chemotherapeutics. The physicochemical characteristics of synthesized KM-entrapped PLGA NPs were investigated by XRD, FTIR, zeta potential, and TEM. The KM + FA + PLGA NPs showed particle size with 132.9 ± 1.4 nm, zeta potential -15.0 ± 1.73 mV, encapsulation efficiency 67.92 ± 4.8, and drug-loading capacity 0.463 ± 0.173. In vitro cytotoxicity study on HT-29 cell lines using the MTT assay, the apoptotic study revealed that KM + FA + PLGA NPs have an enhanced cytotoxic effect compared to the KM + PLGA NPs drug solution. These findings suggested that KM + FA + PLGA NPs could be an effective chemotherapeutic drug delivery system in colon adenocarcinoma HT-29 cells.

Sustained Drug Release from Smart Nanoparticles in Cancer Therapy: A Comprehensive Review

Although nanomedicine has been highly investigated for cancer treatment over the past decades, only a few nanomedicines are currently approved and in the market; making this field poorly represented in clinical applications. Key research gaps that require optimization to successfully translate the use of nanomedicines have been identified, but not addressed; among these, the lack of control of the release pattern of therapeutics is the most important. To solve these issues with currently used nanomedicines (e.g., burst release, systemic release), different strategies for the design and manufacturing of nanomedicines allowing for better control over the therapeutic release, are currently being investigated. The inclusion of stimuli-responsive properties and prolonged drug release have been identified as effective approaches to include in nanomedicine, and are discussed in this paper. Recently, smart sustained release nanoparticles have been successfully designed to safely and efficiently deliver therapeutics with different kinetic profiles, making them promising for many drug delivery applications and in specific for cancer treatment. In this review, the state-of-the-art of smart sustained release nanoparticles is discussed, focusing on the design strategies and performances of polymeric nanotechnologies. A complete list of nanomedicines currently tested in clinical trials and approved nanomedicines for cancer treatment is presented, critically discussing advantages and limitations with respect to the newly developed nanotechnologies and manufacturing methods. By the presented discussion and the highlight of nanomedicine design criteria and current limitations, this review paper could be of high interest to identify key features for the design of release-controlled nanomedicine for cancer treatment.

Antifungal Encapsulated into Ligand-Functionalized Nanoparticles with High Specificity for Macrophages

Infectious diseases caused by intracellular microorganisms such as Histoplasma capsulatum represent a significant challenge worldwide. Drug encapsulation into functionalized nanoparticles (NPs) is a valuable alternative to improving drug solubility and bioavailability, preventing undesirable interactions and drug degradation, and reaching the specific therapeutic target with lower doses. This work reports on Itraconazole (ITZ) encapsulated into core-shell-like polymeric NPs and functionalized with anti-F4/80 antibodies for their targeted and controlled release into macrophages. Uptake assay on co-culture showed significant differences between the uptake of functionalized and bare NPs, higher with functionalized NPs. In vitro assays showed that F4/80-NPs with 0.007 µg/mL of encapsulated ITZ eliminated the H. capsulatum fungus in co-culture with macrophages effectively compared to the bare NPs, without any cytotoxic effect on macrophages after 24 h interaction. Furthermore, encapsulated ITZ modulated the gene expression of anti and pro-inflammatory cytokines (IL-1, INF-Y, IL-6 and IL-10) on macrophages. Additionally, the anti-F4/80 antibody-coating enhanced natural and adequate antifungal response in the cells, exerting a synergistic effect that prevented the growth of the fungus at the intracellular level. Functionalized NPs can potentially improve macrophage-targeted therapy, increasing NPs endocytosis and intracellular drug concentration.

Native PLGA nanoparticles regulate APP metabolism and protect neurons against β-amyloid toxicity: Potential significance in Alzheimer's disease pathology

Biodegradable poly(lactic-co-glycolic acid)(PLGA) nanoparticles have been used extensively in delivering drugs to target tissues due to their excellent biocompatibility. Evidence suggests that PLGA-conjugated drugs/agents can attenuate pathology in cellular/animal models of Alzheimer's disease (AD), which is initiated by increased level/aggregation of amyloid β (Aβ) peptide generated from amyloid precursor protein (APP). The beneficial effects were attributed to conjugated-drugs rather than to PLGA nanoparticles. Interestingly, we recently reported that PLGA without any drug/agent (native PLGA) can suppress Aβ aggregation/toxicity. However, very little is known about the internalization, subcellular localization or effects of PLGA in neurons. In this study, using primary mouse cortical neurons, we first showed that native PLGA is internalized by an energy-mediated clathrin-dependent/-independent pathway and is localized in endosomal-lysosomal-autophagic vesicles. By attenuating internalization, PLGA can protect neurons against Aβ-mediated toxicity. Additionally, PLGA treatment altered expression profiles of certain AD-associated genes and decreased the levels of APP, its cleaved products α-/β-CTFs and Aβ peptides in mouse as well as iPSC-derived neurons from control and AD patients. Collectively, these results suggest that native PLGA not only protects neurons against Aβ-induced toxicity but also influences the expression of AD-related genes/proteins - highlighting PLGA's implication in normal and AD-related pathology.

Preparation of size-tunable sub-200 nm PLGA-based nanoparticles with a wide size range using a microfluidic platform

The realization of poly (lactic-co-glycolic acid) nanoparticles (PLGA NPs) from laboratory to clinical applications remains slow, partly because of the lack of precise control of each condition in the preparation process and the rich selectivity of nanoparticles with diverse characteristics. Employing PLGA NPs to establish a large range of size-controlled drug delivery systems and achieve size-selective drug delivery targeting remains a challenge for therapeutic development for different diseases. In this study, we employed a microfluidic device to control the size of PLGA NPs. PLGA, poly (ethylene glycol)-methyl ether block poly (lactic-co-glycolide) (PEG-PLGA), and blend (PLGA + PEG-PLGA) NPs were engineered with defined sizes. Blend NPs exhibit the widest size range (40–114 nm) by simply changing the flow rate conditions without changing the precursor (polymer molecular weight, concentration, and chain segment composition). A model hydrophobic drug, paclitaxel (PTX), was encapsulated in the NPs, and the PTX-loaded NPs maintained a large range of controllable NP sizes. Furthermore, size-controlled NPs were used to investigate the effect of particle size of sub-200 nm NPs on tumor cell growth. The 52 nm NPs showed higher cell growth inhibition than 109 nm NPs. Our method allows the preparation of biodegradable NPs with a large size range without changing polymer precursors as well as the nondemanding fluid conditions. In addition, our model can be applied to elucidate the role of particle sizes of sub-200 nm particles in various biomedical applications, which may help develop suitable drugs for different diseases.

Temozolomide: an Overview of Biological Properties, Drug Delivery Nanosystems, and Analytical Methods

Temozolomide (TMZ) is an imidazotetrazine prodrug used to treat glioblastoma multiforme. Its physicochemical prop-erties and small size confer the ability to cross the blood-brain barrier. The antitumor activity depends on pH-dependent hydrolysis of the methyldiazonium cation, which is capable of methylating purine bases (O6-guanine; N7-guanine, and N3-adenine) and causing DNA damage and cell death. TMZ is more stable in acidic media (pH ≤ 5.0) than in basic media (pH ≥ 7.0) due to the protonated form that minimizes the catalytic process. Because of this, TMZ has high oral bioavailability, but it has a half-life of 1.8 h and low brain distribution (17.8%), requiring a repeated dos-ing regimen that limits its efficacy and increases adverse events. Drug delivery Nanosystems (DDNs) improve the phys-icochemical properties of TMZ and may provide controlled and targeted delivery. Therefore, DDNs can increase the efficacy and safety of TMZ. In this context, to ensure the efficiency of DDNs, analytical methods are used to evaluate TMZ pharmacokinetic parameters, encapsulation efficiency, and the release profile of DDNs. Among the methods, high-performance liquid chromatography is the most used due to its detection sensitivity in complex matrices such as tissues and plasma. Micellar electrokinetic chromatography features fast analysis and no sample pretreatment. Spec-trophotometric methods are still used to determine encapsulation efficiency due to their low cost, despite their low sen-sitivity. This review summarizes the physicochemical and pharmacological properties of free TMZ and TMZ-loaded DDNs. In addition, this review addresses the main analytical methods employed to characterize TMZ in different ma-trices.

Use of Polyesters in Fused Deposition Modeling for Biomedical Applications

In recent years, 3D printing techniques experienced a growing interest in several sectors, including the biomedical one. Their main advantage resides in the possibility to obtain complex and personalized structures in a cost-effective way impossible to achieve with traditional production methods. This is especially true for Fused Deposition Modeling (FDM), one of the most diffused 3D printing methods. The easy customization of the final products' geometry, composition and physico-chemical properties is particularly interesting for the increasingly personalized approach adopted in modern medicine. Thermoplastic polymers are the preferred choice for FDM applications, and a wide selection of biocompatible and biodegradable materials is available to this aim. Moreover, these polymers can also be easily modified before and after printing to better suit the body environment and the mechanical properties of biological tissues. This review focuses on the use of thermoplastic aliphatic polyesters for FDM applications in the biomedical field. In detail, the use of poly(ε-caprolactone), poly(lactic acid), poly(lactic-co-glycolic acid), poly(hydroxyalkanoate)s, thermo-plastic poly(ester urethane)s and their blends has been thoroughly surveyed, with particular attention to their main features, applicability and workability. The state-of-the-art is presented and current challenges in integrating the additive manufacturing technology in the medical practice are discussed. This article is protected by copyright. All rights reserved.

Discovery and Photoisomerization of New Pyrrolosesquiterpenoids Glaciapyrroles D and E, from Deep-Sea Sediment Streptomyces sp

Two new pyrrolosesquiterpenes, glaciapyrroles D (1) and E (2) were discovered along with the previously reported glaciapyrrole A (3) from Streptomyces sp. GGS53 strain isolated from deep-sea sediment. This study elucidated the planar structures of 1 and 2 using nuclear magnetic resonance (NMR), mass spectrometry (MS), ultraviolet (UV), and infrared (IR) spectroscopic data. The absolute configurations of the glaciapyrroles were determined by Mosher’s method, circular dichroism spectroscopy, and X-ray crystallography. Under 366 nm UV irradiation, the glaciapyrroles were systematically converted to the corresponding photoglaciapyrroles (4–6) via photoisomerization, resulting in the diversification of the glaciapyrrole family compounds. The transformation of the glaciapyrrole Z to E isomers occurred in a 1:1 ratio, based on virtual validation of the photoisomerization of these olefinic compounds by ¹H-NMR spectroscopy and liquid chromatography/mass spectrometry (LC/MS) analysis. Finally, when encapsulated in poly(lactic-co-glycolic acid) nanoparticles, glaciapyrrole E and photoglaciapyrrole E displayed significant inhibitory activity against influenza A virus. This is the first report of antiviral effects from glaciapyrrole family compounds, whose biological functions have only been subjected to limited studies so far.

Nanodelivery of essential oils as efficient tools against antimicrobial resistance: a review of the type and physical-chemical properties of the delivery systems and applications

This review provides a synthesis of the last ten years of research on nanodelivery systems used for the delivery of essential oils (EOs), as well as their potential as a viable alternative to antibiotics in human and veterinary therapy. The use of essential oils alone in therapy is not always possible due to several limitations but nanodelivery systems seem to be able to overcome these issues. The choice of the essential oil, as well as the choice of the nanodelivery system influences the therapeutic efficacy obtained. While several studies on the characterization of EOs exist, this review assesses the characteristics of the nanomaterials used for the delivery of essential oils, as well as impact on the functionality of nanodelivered essential oils, and successful applications. Two classes of delivery systems stand out: polymeric nanoparticles (NPs) including chitosan, cellulose, zein, sodium alginate, and poly(lactic-co-glycolic) acid (PLGA), and lipidic NPs including nanostructured lipid carriers, solid lipid NPs, nanoemulsions, liposomes, and niosomes. While the advantages and disadvantages of these delivery systems and information on stability, release, and efficacy of the nanodelivered EOs are covered in the literature as presented in this review, essential information, such as the speed of emergence of a potential bacteria resistance to these new systems, or dosages for each type of infection and for each animal species or humans is still missing today. Therefore, more quantitative and in vivo studies should be conducted before the adoption of EOs loaded NPs as an alternative to antibiotics, where appropriate.

Magnetic Nano-Platform Enhanced iPSC-Derived Trabecular Meshwork Delivery and Tracking Efficiency

Purpose

Transplantation of stem cells to remodel the trabecular meshwork (TM) has become a new option for restoring aqueous humor dynamics and intraocular pressure homeostasis in glaucoma. In this study, we aimed to design a nanoparticle to label induced pluripotent stem cell (iPSC)-derived TM and improve the delivery accuracy and in vivo tracking efficiency.

Methods

PLGA-SPIO-Cypate (PSC) NPs were designed with polylactic acid-glycolic acid (PLGA) polymers as the backbone, superparamagnetic iron oxide (SPIO) nanoparticles, and near-infrared (NIR) dye cypate. In vitro assessment of cytotoxicity, iron content after NPs labeling, and the dual-model monitor was performed on mouse iPSC-derived TM (miPSC-TM) cells, as well as immortalized and primary human TM cells. Cell function after labeling, the delivery accuracy, in vivo tracking efficiency, and its effect on lowering IOP were evaluated following miPSC-TM transplantation in mice.

Results

Initial in vitro experiments showed that a single-time nanoparticles incubation was sufficient to label iPSC-derived TM and was not related to any change in both cell viability and fate. Subsequent in vivo evaluation revealed that the use of this nanoparticle not only improves the delivery accuracy of the transplanted cells in live animals but also benefits the dual-model tracking in the long term. More importantly, the use of the magnet triggers a temporary enhancement in the effectiveness of cell-based therapy in alleviating the pathologies associated with glaucoma.

Conclusion

This study provided a promising approach for enhancing both the delivery and in vivo tracking efficiency of the transplanted cells, which facilitates the clinical translation of stem cell-based therapy for glaucoma.

K, Pilaquinga F, Kumar B, Debut A. Comparative statistical analysis of the release kinetics models for nanoprecipitated drug delivery systems based on poly(lactic-co-glycolic acid)

Poly(lactic-co-glycolic acid) is one of the most used polymers for drug delivery systems (DDSs). It shows excellent biocompatibility, biodegradability, and allows spatio-temporal control of the release of a drug by altering its chemistry. In spite of this, few formulations have reached the market. To characterize and optimize the drug release process, mathematical models offer a good alternative as they allow interpreting and predicting experimental findings, saving time and money. However, there is no general model that describes all types of drug release of polymeric DDSs. This study aims to perform a statistical comparison of several mathematical models commonly used in order to find which of them best describes the drug release profile from PLGA particles synthesized by nanoprecipitation method. For this purpose, 40 datasets extracted from scientific articles published since 2016 were collected. Each set was fitted by the models: order zero to fifth order polynomials, Korsmeyer-Peppas, Weibull and Hyperbolic Tangent Function. Some data sets had few observations that do not allow to apply statistic test, thus bootstrap resampling technique was performed. Statistic evidence showed that Hyperbolic Tangent Function model is the one that best fit most of the data.

PLGA-Based Composites for Various Biomedical Applications

Polymeric materials have been extensively explored in the field of nanomedicine; within them, poly lactic-co-glycolic acid (PLGA) holds a prominent position in micro- and nanotechnology due to its biocompatibility and controllable biodegradability. In this review we focus on the combination of PLGA with different inorganic nanomaterials in the form of nanocomposites to overcome the polymer’s limitations and extend its field of applications. We discuss their physicochemical properties and a variety of well-established synthesis methods for the preparation of different PLGA-based materials. Recent progress in the design and biomedical applications of PLGA-based materials are thoroughly discussed to provide a framework for future research.

Improving Antibacterial Activity of a HtrA Protease Inhibitor JO146 against Helicobacter pylori: A Novel Approach Using Microfluidics-Engineered PLGA Nanoparticles

Nanoparticle drug delivery systems have emerged as a promising strategy for overcoming limitations of antimicrobial drugs such as stability, bioavailability, and insufficient exposure to the hard-to-reach bacterial drug targets. Although size is a vital colloidal feature of nanoparticles that governs biological interactions, the absence of well-defined size control technology has hampered the investigation of optimal nanoparticle size for targeting bacterial cells. Previously, we identified a lead antichlamydial compound JO146 against the high temperature requirement A (HtrA) protease, a promising antibacterial target involved in protein quality control and virulence. Here, we reveal that JO146 was active against Helicobacter pylori with a minimum bactericidal concentration of 18.8–75.2 µg/mL. Microfluidic technology using a design of experiments approach was utilized to formulate JO146-loaded poly(lactic-co-glycolic) acid nanoparticles and explore the effect of the nanoparticle size on drug delivery. JO146-loaded nanoparticles of three different sizes (90, 150, and 220 nm) were formulated with uniform particle size distribution and drug encapsulation efficiency of up to 25%. In in vitro microdilution inhibition assays, 90 nm nanoparticles improved the minimum bactericidal concentration of JO146 two-fold against H. pylori compared to the free drug alone, highlighting that controlled engineering of nanoparticle size is important in drug delivery optimization.

Development of Peptide Targeted PLGA-PEGylated Nanoparticles Loading Licochalcone-A for Ocular Inflammation

Licochalcone-A is a natural compound with anti-inflammatory properties. However, it possesses low water solubility, making its application for the treatment of ocular inflammation difficult. To overcome this drawback, biodegradable nanoparticles incorporating Licochalcone-A have been developed. Additionally, to avoid fast clearance and increase cellular internalization into the ocular tissues, PLGA nanoparticles have been functionalized using PEG and cell penetrating peptides (Tet-1 and B6). To optimize the formulations, a factorial design was carried out and short-term stability of the nanoparticles was studied. Moreover, morphology was also observed by transmission electron microcopy and in vitro drug release was carried out. Ocular tolerance of the formulations was ensured in vitro and in vivo and anti-inflammatory therapeutic efficacy was also assessed. Surface functionalized nanoparticles loading Licochalcone-A were developed with an average size below 200 nm, a positive surface charge, and a monodisperse population. The formulations were non-irritant and showed a prolonged Licochalcone-A release. Despite the fact that both Licochalcone-A Tet-1 and B6 functionalized nanoparticles demonstrated to be suitable for the treatment of ocular inflammation, B6 targeted nanoparticles provided greater therapeutic efficacy in in vivo assays.

Recent Advances in the Surface Functionalization of PLGA-Based Nanomedicines

Therapeutics are habitually characterized by short plasma half-lives and little affinity for targeted cells. To overcome these challenges, nanoparticulate systems have entered into the disease arena. Poly(d,l-lactide-co-glycolide) (PLGA) is one of the most relevant biocompatible materials to construct drug nanocarriers. Understanding the physical chemistry of this copolymer and current knowledge of its biological fate will help in engineering efficient PLGA-based nanomedicines. Surface modification of the nanoparticle structure has been proposed as a required functionalization to optimize the performance in biological systems and to localize the PLGA colloid into the site of action. In this review, a background is provided on the properties and biodegradation of the copolymer. Methods to formulate PLGA nanoparticles, as well as their in vitro performance and in vivo fate, are briefly discussed. In addition, a special focus is placed on the analysis of current research in the use of surface modification strategies to engineer PLGA nanoparticles, i.e., PEGylation and the use of PEG alternatives, surfactants and lipids to improve in vitro and in vivo stability and to create hydrophilic shells or stealth protection for the nanoparticle. Finally, an update on the use of ligands to decorate the surface of PLGA nanomedicines is included in the review.

Inhalation potential of N-Acetylcysteine loaded PLGA nanoparticles for the management of tuberculosis: In vitro lung deposition and efficacy studies

Several studies have stated that mucus is a critical hurdle for drug delivery to the mucosal tissues. As a result, Polymeric nanoparticles that can overcome mucus barriers are gaining popularity for controlled drug delivery into intra-macrophages to attain high intracellular drug concentration. The present study was aimed to fabricate inhalable N-acetylcysteine (NAC) modified PLGA mucus penetrating particles using the double emulsion method (w/o/w) for target delivery to alveolar macrophages and minimize the dose-related adverse effects, efficiently encapsulate hydrophilic drug, sustain the release profile and prolong the retention time for the management of tuberculosis. Among the numerous formulations, the drug/polymer ratio of 1:10 with 0.50% PVA concentration and sonication time for 2 ​min ​s was chosen for further research. The formulated nanoparticles had a mean particle size of 307.50 ​± ​9.54 ​nm, PDI was 0.136 ​± ​0.02, zeta potential about -11.3 ​± ​0.4 ​mV, decent entrapment efficiency (55.46 ​± ​2.40%), drug loading (9.05 ​± ​0.22%), and excellent flowability. FTIR confirmed that NAC and PLGA were compatible with each other. SEM graphs elucidated that the nanoparticles were spherically shaped with a slightly rough surface whereas TEM analysis ensured the nanometer size nanoparticles and coating of lipid over NPs surface. PXRD spectrum concluded the transformation of the drug from crystalline to amorphous state in the formulation. In vitro release pattern was biphasic started with burst release (64.67 ​± ​1.53% within 12hrs) followed by sustained release over 48hrs thus enabling the prolonged replenishing of NAC. In vitro lung deposition study pronounced that coated NAC-PLGA-MPPs showed favorable results in terms of emitted dose (86.67 ​± ​2.52%), MMAD value (2.57 ​± ​0.12 ​μm), GSD value (1.55 ​± ​0.11 ​μm), and FPF of 62.67 ​± ​2.08% for the deposition and targeting the lungs. Finally, in vitro efficacy studies demonstrated that NAC-PLGA-MPPs presented more prominent antibacterial activity against MTB H37Rv strain as compared to NAC. Hence, PLGA based particles could be a better strategy to deliver the NAC for lung targeting.

Overcoming MDR by Associating Doxorubicin and pH-Sensitive PLGA Nanoparticles Containing a Novel Organoselenium Compound-An In Vitro Study

In this study, we developed PLGA nanoparticles (NPs) as an effective carrier for 5'-Se-(phenyl)-3-(amino)-thymidine (ACAT-Se), an organoselenium compound, nucleoside analogue that showed promising antitumor activity in vitro. The PLGA NPs were prepared by the nanoprecipitation method and modified with a pH-responsive lysine-based surfactant (77KL). The ACAT-Se-PLGA-77KL-NPs presented nanometric size (around 120 nm), polydispersity index values < 0.20 and negative zeta potential values. The nanoencapsulation of ACAT-Se increased its antioxidant (DPPH and ABTS assays) and antitumor activity in MCF-7 tumor cells. Hemolysis study indicated that ACAT-Se-PLGA-77KL-NPs are hemocompatible and that 77KL provided a pH-sensitive membranolytic behavior to the NPs. The NPs did not induce cytotoxic effects on the nontumor cell line 3T3, suggesting its selectivity for the tumor cells. Moreover, the in vitro antiproliferative activity of NPs was evaluated in association with the antitumor drug doxorubicin. This combination result in synergistic effect in sensitive (MCF-7) and resistant (NCI/ADR-RES) tumor cells, being especially able to successfully sensitize the MDR cells. The obtained results suggested that the proposed ACAT-Se-loaded NPs are a promising delivery system for cancer therapy, especially associated with doxorubicin.

Injectable nanocomposite hydrogels as an emerging platform for biomedical applications: A review

Hydrogels have attracted much attention for biomedical and pharmaceutical applications due to the similarity of their biomimetic structure to the extracellular matrix of natural living tissues, tunable soft porous microarchitecture, superb biomechanical properties, proper biocompatibility, etc. Injectable hydrogels are an exciting type of hydrogels that can be easily injected into the target sites using needles or catheters in a minimally invasive manner. The more comfortable use, less pain, faster recovery period, lower costs, and fewer side effects make injectable hydrogels more attractive to both patients and clinicians in comparison to non-injectable hydrogels. However, it is difficult to achieve an ideal injectable hydrogel using just a single material (i.e., polymer). This challenge can be overcome by incorporating nanofillers into the polymeric matrix to engineer injectable nanocomposite hydrogels with combined or synergistic properties gained from the constituents. This work aims to critically review injectable nanocomposite hydrogels, their preparation methods, properties, functionalities, and versatile biomedical and pharmaceutical applications such as tissue engineering, drug delivery, and cancer labeling and therapy. The most common natural and synthetic polymers as matrices together with the most popular nanomaterials as reinforcements, including nanoceramics, carbon-based nanostructures, metallic nanomaterials, and various nanosized polymeric materials, are highlighted in this review.

Preparation of chelidonine highly loaded poly(lactide-co-glycolide)-based nanoparticles using a single emulsion method: Cytotoxic effect on MDA-MB-231 cell line

Introduction: Chelidonine, a bio-active component of Chelidonium majus, has been investigated for its anti-proliferative effects on various cancer cell lines with multidrug resistance (MDR). Although the results are auspicious, its poor water solubility and low bioavailability are the main limitations for clinical applications. This study aimed to develop poly(lactic-co-glycolic acid) (PLGA) nanoparticles loaded with chelidonine, in order to enhance its bioavailability for oral administration and improve the therapeutic index. Methods: Herein, we encapsulated chelidonine in PLGA nanoparticles using a single emulsion solvent evaporation method. Nanoparticles were characterized in terms of size, surface charge and morphology, encapsulation efficiency, drug loading, and in vitro drug release profile. The anti-cancer efficacy of chelidonine-loaded nanoparticles and free chelidonine was evaluated in MDA-MB-231 breast cancer cells. Results: The physicochemical characteristics showed spherical particles in nanometer size range (263 ± 19.6 nm), with negative surface charge (−20.67 ± 2.48 mv), high encapsulation efficiency (76.53 ± 3.61%), and drug loading (22.47 ± 0.09%), as well as drug release amount of 60.27±5.68% up to 10 days. Furthermore, chelidonine-loaded nanoformulations were found to improve anti-cancer potential, compared with unentrapped chelidonine. Conclusion: This in vitro study showed that the encapsulation of chelidonine, as a potent herbal drug, in a polymeric matrix enhances its bioavailability. This offers an efficient vehicle for targeted drug delivery in cancer treatment.

Development of topical eye-drops of lactoferrin-loaded biodegradable nanoparticles for the treatment of anterior segment inflammatory processes

Ocular inflammation is one of the most common comorbidities associated to ophthalmic surgeries and disorders. Since conventional topical ophthalmic treatments present disadvantages such as low bioavailability and relevant side effects, natural alternatives constitute an unmet medical need. In this sense, lactoferrin, a high molecular weight protein, is a promising alternative against inflammation. However, lactoferrin aqueous instability and high nasolacrimal duct drainage compromises its potential effectiveness. Moreover, nanotechnology has led to an improvement in the administration of active compounds with compromised biopharmaceutical profiles. Here, we incorporate lactoferrin into biodegradable polymeric nanoparticles and optimized the formulation using the design of experiments approach. A monodisperse nanoparticles population was obtained with an average size around 130 nm and positive surface charge. Pharmacokinetic and pharmacodynamic behaviour were improved by the nanoparticles showing a prolonged lactoferrin release profile. Lactoferrin nanoparticles were non-cytotoxic and non-irritant neither in vitro nor in vivo. Moreover, nanoparticles exhibited significantly increased anti-inflammatory efficacy in cell culture and preclinical assays. In conclusion, lactoferrin loaded nanoparticles constitute a safe and novel nanotechnological tool suitable for the treatment of ocular inflammation.

Optimization, Characterization and Pharmacokinetic Study of Meso-Tetraphenylporphyrin Metal Complex-Loaded PLGA Nanoparticles

The selection of technological parameters for nanoparticle formulation represents a complicated development phase. Therefore, the statistical analysis based on Box-Behnken methodology is widely used to optimize technological processes, including poly(lactic-co-glycolic acid) nanoparticle formulation. In this study, we applied a two-level three-factor design to optimize the preparation of nanoparticles loaded with cobalt (CoTPP), manganese (MnClTPP), and nickel (NiTPP) metalloporphyrins (MeP). The resulting nanoparticles were examined by dynamic light scattering, X-ray diffraction, Fourier transform infrared spectroscopy, MTT test, and hemolytic activity assay. The optimized model of nanoparticle formulation was validated, and the obtained nanoparticles possessed a spherical shape and physicochemical characteristics enabling them to deliver MeP in cancer cells. In vitro hemolysis assay revealed high safety of the formulated MeP-loaded nanoparticles. The MeP release demonstrated a biphasic profile and release mechanism via Fick diffusion, according to release exponent values. Formulated MeP-loaded nanoparticles revealed significant antitumor activity and ability to generate reactive oxygen species. MnClTPP- and CoTPP-nanoparticles specifically accumulated in tissues, preventing wide tissue distribution caused by long-term circulation of the hydrophobic drug. Our results suggest that MnClTPP- and CoTPP-nanoparticles represent the greatest potential for utilization in in anticancer therapy due to their effectiveness and safety.

Naringin as Sustained Delivery Nanoparticles Ameliorates the Anti-inflammatory Activity in a Freund's Complete Adjuvant-Induced Arthritis Model

Naringin (NAR), a naturally occurring essential flavonoid, present in grapefruit and Chinese herbal medicines, creates great interest in researchers due to its diverse biological and pharmacological activities. However, further development of NAR is hindered due to its poor water solubility and dissolution rates in GIT. To address these limitations, in this study, we report polymeric nanoparticles (NPs) of NAR (NAR-PLGA-NPs) for enhancing the oral NAR efficiency, with a biodegradable polymer (PLGA) to improve its absorption and bioavailability. NAR-PLGA-NPs were fabricated by a modified solvent emulsification-evaporation technique. Physicochemical properties were evaluated by SEM, particle size distribution, entrapment efficiency, Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), and differential scanning calorimetry (DSC). In vitro drug release and ex vivo permeation studies were carried out in phosphate buffer (pH 6.8) for 24 h. Furthermore, in vivo anti-arthritic studies were performed on a mouse model, and the results were compared with free NAR. The modulation of inflammatory mediators was also evidently supported by docking studies. Optimized nanoformulation FN4 (NAR-PLGA-NPs) prepared with acetone-ethanol (2:1) as a solvent system in a combination of stabilizers, i.e., poloxamer-188 and sodium deoxylate (1:1), along with 2% PVA solution, was prepared. From size characterization studies, it was observed that nanoformulations possessed a low particle size (179.7 ± 2.05 nm), a low polydispersity index (0.206 ± 0.001), and a negative zeta potential (-9.18 ± 0.78 mV) with a maximum entrapment efficiency (74 ± 3.61%). The drug release followed a Korsmeyer-Peppas release kinetic model (anomalous non-Fickian diffusion), providing greater NAR release after lyophilization (82.11 ± 3.65%) drug release in pH 6.8 phosphate buffer for 24 h. Ex vivo permeation analysis through an isolated goat intestinal membrane revealed 80.02 ± 3.69% drug release in 24 h. Encapsulation of a drug into PLGA is well described by the results of FTIR, DSC, and XRD. Finally, the therapeutic efficacy of optimized FN4 (NAR-PLGA-NPs) and its possible application on RA were further confirmed in a Freund's complete adjuvant-induced rat arthritic model as against free NAR at a dose of 20 mg/kg body wt. Our findings demonstrate that sustained action of NAR from optimized FN4 NPs with a rate-controlling polymeric carrier system exhibited prolonged circulation time and reduced arthritic inflammation, hence indicating the possibility as a novel strategy to secure the unpropitious biological interactions of hydrophobic NAR in a gastric environment.

Contribution of Nanotechnologies to Vaccine Development and Drug Delivery against Respiratory Viruses

According to the Center for Disease Control and Prevention (CDC), the coronavirus disease 2019, a respiratory viral illness linked to significant morbidity, mortality, production loss, and severe economic depression, was the third-largest cause of death in 2020. Respiratory viruses such as influenza, respiratory syncytial virus, SARS-CoV-2, and adenovirus, are among the most common causes of respiratory illness in humans, spreading as pandemics or epidemics throughout all continents. Nanotechnologies are particles in the nanometer range made from various compositions. They can be lipid-based, polymer-based, protein-based, or inorganic in nature, but they are all bioinspired and virus-like. In this review, we aimed to present a short review of the different nanoparticles currently studied, in particular those which led to publications in the field of respiratory viruses. We evaluated those which could be beneficial for respiratory disease-based viruses; those which already have contributed, such as lipid nanoparticles in the context of COVID-19; and those which will contribute in the future either as vaccines or antiviral drug delivery systems. We present a short assessment based on a critical selection of evidence indicating nanotechnology's promise in the prevention and treatment of respiratory infections.

Chitosan-Coated PLGA Nanoparticles Encapsulating Triamcinolone Acetonide as a Potential Candidate for Sustained Ocular Drug Delivery

The current treatment for the acquired retinal vasculopathies involves lifelong repeated intravitreal injections of either anti-vascular endothelial growth factor (VEGF) therapy or modulation of inflammation with steroids. Consequently, any treatment modification that decreases this treatment burden for patients and doctors alike would be a welcome intervention. To that end, this research aims to develop a topically applied nanoparticulate system encapsulating a corticosteroid for extended drug release. Poly (lactic-co-glycolic acid) (PLGA) nanoparticles (NPs) supports the controlled release of the encapsulated drug, while surface modification of these NPs with chitosan might prolong the mucoadhesion ability leading to improved bioavailability of the drug. Triamcinolone acetonide (TA)-loaded chitosan-coated PLGA NPs were fabricated using the oil-in-water emulsion technique. The optimized surface-modified NPs obtained using Box-Behnken response surface statistical design were reproducible with a particle diameter of 334 ± 67.95 to 386 ± 15.14 nm and PDI between 0.09 and 0.15. These NPs encapsulated 55-57% of TA and displayed a controlled release of the drug reaching a plateau in 27 h. Fourier-transform infrared spectroscopic (FTIR) analysis demonstrated characteristic peaks for chitosan (C-H, CONH2 and C-O at 2935, 1631 and 1087 cm-1, respectively) in chitosan-coated PLGA NPs. This result data, coupled with positive zeta potential values (ranged between +26 and +33 mV), suggests the successful coating of chitosan onto PLGA NPs. Upon coating of the NPs, the thermal stability of the drug, polymer, surfactant and PLGA NPs have been enhanced. The characteristics of the surface-modified NPs supports their use as potential candidates for topical ocular drug delivery for acquired retinal vasculopathies.

Herbal Nanoformulations for Asthma Treatment

BACKGROUND

In recent decades, the prevalence of asthma has substantially increased worldwide. Advances in phytochemistry and phytopharmacology have clarified the active ingredients and biological activities of medicinal plant products for treating asthma, and the role of herbal therapies in asthma treatment has become increasingly evident. However, most plant extracts have low solubility and poor stability of bioactive components, resulting in low bioavailability and loss of efficacy. Owing to these shortcomings, the clinical use of many herbal extracts is limited.

OBJECTIVE

To summarise and analyse the characteristics of herbal nanoformulations and their application in asthma treatment. The objective of this review article is to address the emerging trends of herbal nanoformulations for an effective treatment for asthma.

METHODS

Various research and review articles from reputed international journals were referred and compiled.

RESULTS

The nano-sized herbal formulations improve the solubility and bioavailability of herbal medicines and contribute to the sustained release of drugs, thus, increasing the therapeutic applications of herbal extracts. The review present different types of herbal nanoformulations, including micelles, nanoparticles, solid lipid nanoparticles, lipid-based liquid crystalline nanoparticles and nanoemulsions, which are potential nanodrugs for asthma treatment.

CONCLUSIONS

Herbal nanoformulations have shown great prospects for treatment of asthma in recent years. More safety and toxicity data are still needed to promote their development and application.

Recent Progress in Phthalocyanine-Polymeric Nanoparticle Delivery Systems for Cancer Photodynamic Therapy

This perspective article summarizes the last decade’s developments in the field of phthalocyanine (Pc)-polymeric nanoparticle (NP) delivery systems for cancer photodynamic therapy (PDT), including studies with at least in vitro data. Moreover, special attention will be paid to the various strategies for enhancing the behavior of Pc-polymeric NPs in PDT, underlining the great potential of this class of nanomaterials as advanced Pcs’ nanocarriers for cancer PDT. This review shows that there is still a lot of research to be done, opening the door to new and interesting nanodelivery systems.

Oseltamivir phosphate loaded pegylated-Eudragit nanoparticles for lung cancer therapy: Characterization, prolonged release, cytotoxicity profile, apoptosis pathways and in vivo anti-angiogenic effect by using CAM assay

The target of the current investigation was the delivery of oseltamivir phosphate (OSE) into the lung adenocarcinoma tissues by means of designing nanosized, non-toxic and biocompatible pegylated Eudragit based NPs and investigating their anticancer and antiangiogenic activity. The rationale for this strategy is to provide a novel perspective to cancer treatment with OSE loaded pegylated ERS NPs under favor of smaller particle size, biocompatible feature, cationic characteristic, examining their selective effectiveness on lung cell lines (A549 lung cancer cell line and CCD-19Lu normal cell line) and examining antiangiogenic activity by in vivo CAM analysis. For this purpose, OSE encapsulated pegylated ERS based NPs were developed and investigated for zeta potential, particle size, encapsulation efficiency, morphology, DSC, FT-IR, ¹H NMR analyses. In vitro release, cytotoxicity, determination apoptotic pathways and in vivo CAM assay were carried out. Considering characterizations, NPs showed smaller particle size, cationic zeta potential, relatively higher EE%, nearly spherical shape, amorphous matrix formation and prolonged release pattern (Peppas-Sahlin and Weibull model with Fickian and non-Fickian release mechanisms). Flow cytometry was used to assess the apoptotic pathways using the Annexin V-FITC/PI staining assay, FITC Active Caspase-3 staining assay, and mitochondrial membrane potential detection tests. Activations on caspase-3 pathways made us think that OSE loaded pegylated ERS NPs triggered to apoptosis using intrinsic pathway. As regards to the in vivo studies, OSE loaded pegylated ERS based NPs demonstrated strong and moderate antiangiogenic activity for ERS-OSE 2 and ERS-OSE 3, respectively. With its cationic character, smaller particle size, relative superior EE%, homogenous amorphous polymeric matrix constitution indicated using solid state tests, prolonged release manner, highly selective to the human lung adenocarcinoma cell lines, could trigger apoptosis intrinsically and effectively, possess good in vivo antiangiogenic activity, ERS-OSE 2 formulation is chosen as a promising candidate and a potent drug delivery system to treat lung cancer.

Recent perspectives of nanotechnology in burn wounds management: a review

OBJECTIVE

The burden of the management of problematic skin wounds characterised by a compromised skin barrier is growing rapidly. Almost six million patients are affected in the US alone, with an estimated market of $25 billion annually. There is an urgent requirement for efficient mechanism-based treatments and more efficacious drug delivery systems. Novel strategies are needed for faster healing by reducing infection, moisturising the wound, stimulating the healing mechanisms, speeding up wound closure and reducing scar formation.

METHODS

A systematic review of qualitative studies was conducted on the recent perspectives of nanotechnology in burn wounds management. Pubmed, Scopus, EMBASE, CINAHL and PsychINFO databases were all systematically searched. Authors independently rated the reporting of the qualitative studies included. A comprehensive literature search was conducted covering various resources up to 2018-2019. Traditional techniques aim to simply cover the wound without playing any active role in wound healing. However, nanotechnology-based solutions are being used to create multipurpose biomaterials, not only for regeneration and repair, but also for on-demand delivery of specific molecules. The chronic nature and associated complications of nonhealing wounds have led to the emergence of nanotechnology-based therapies that aim at facilitating the healing process and ultimately repairing the injured tissue.

CONCLUSION

Nanotechnology-based therapy is in the forefront of next-generation therapy that is able to advance wound healing of hard-to-heal wounds. In this review, we will highlight the developed nanotechnology-based therapeutic agents and assess the viability and efficacy of each treatment. Herein we will explore the unmet needs and future directions of current technologies, while discussing promising strategies that can advance the wound-healing field.

Intracellular Targeting of Poly Lactic-Co-Glycolic Acid Nanoparticles by Surface Functionalization with Peptides

Nanoparticles (NPs) are a promising strategy for delivering drugs to specific sites because of their tunable size and surface chemistry variety. Among the availablematerials, NPs prepared with biopolymers are of particular interest because of their biocompatibility and controlled release of encapsulated drugs. Poly lactic-co-glycolic acid (PLGA) is one of the most widely used biopolymers in biomedical applications. In addition to material choice modulation of the interaction between NPs and biological systems is essential for the safety and effective use of NPs. Therefore, this work focused on evaluating different surface functionalization strategies to promote cancer cell uptake and intracellular targeting of PLGA NPs. Herein, cell-penetrating peptides (CPPs) were shown to successfully drive PLGA NPs to the mitochondria and nuclei. Furthermore, the functionalization of PLGA NPs with peptide AC-1001 H3 (GQYGNLWFAY) was proven to be useful for targeting actin filaments. The PLGA NPs cell internalization mechanism by B16F10-Nex2 cells was identified as caveolae-mediated endocytosis, which could be inhibited by the presence of methyl-β-cyclodextrin. Notably, when peptide C (CVNHPAFAC) was used to functionalize PLGA NPs, none of the tested inhibitors could avoid cell internalization of PLGA NPs. Therefore, we suggest this peptide as a promising surface modification agent for enhancing drug delivery to cancer cells. Finally, PLGA NPs showed slow release kinetics and low cytotoxic profile, which, combined with the surface functionalization strategies addressed in this study, highlight the potential of PLGA NPs as a drug delivery platform for improving cancer therapy.

Functional Nanocarriers for Delivering Itraconazole Against Fungal Intracellular Infections

Infectious diseases caused by intracellular microorganisms represent a significant challenge in medical care due to interactions among drugs during coinfections and the development of resistance in microorganisms, limiting existing therapies. This work reports on itraconazole (ITZ) encapsulated into functional polymeric nanoparticles for their targeted and controlled release into macrophages to fight intracellular infections. NPs are based on poly (lactic acid-co-glycolic acid) (PLGA) polymers of different compositions, molecular weights, and lactic acid–to–glycolic acid ratios. They were self-assembled using the high-energy nanoemulsion method and characterized by transmission electron microscopy, Fourier transform infrared spectroscopy (FT-IR), and differential scanning calorimetry. It was studied how the polymer-to-drug ratio, changes in the aqueous phase pH, and type and concentration of surfactant affected nanocarriers’ formation, drug-loading capacity, and encapsulation efficiency. Results showed that drug-loading capacity and encapsulation efficiency reached 6.7 and 80%, respectively, by lowering the pH to 5.0 and using a mixture of surfactants. Optimized formulation showed an initial immediate ITZ release, followed by a prolonged release phase that fitted better with a Fickian diffusion kinetic model and high stability at 4 and 37°C. NPs functionalized by using the adsorption and carbodiimide methods had different efficiencies, the carbodiimide approach being more efficient, stable, and reproducible. Furthermore, linking F4/80 and mannose to the NPs was demonstrated to increase J774A.1 macrophages’ uptake. Overall, in vitro assays showed the nanosystem’s efficacy to eliminate the Histoplasma capsulatum fungus and pave the way to design highly efficient nanocarriers for drug delivery against intracellular infections.

Ophthalmic Sensors and Drug Delivery

Advances in multifunctional materials and technologies have allowed contact lenses to serve as wearable devices for continuous monitoring of physiological parameters and delivering drugs for ocular diseases. Since the tear fluids comprise a library of biomarkers, direct measurement of different parameters such as concentration of glucose, urea, proteins, nitrite, and chloride ions, intraocular pressure (IOP), corneal temperature, and pH can be carried out non-invasively using contact lens sensors. Microfluidic contact lens sensor based colorimetric sensing and liquid control mechanisms enable the wearers to perform self-examinations at home using smartphones. Furthermore, drug-laden contact lenses have emerged as delivery platforms using a low dosage of drugs with extended residence time and increased ocular bioavailability. This review provides an overview of contact lenses for ocular diagnostics and drug delivery applications. The designs, working principles, and sensing mechanisms of sensors and drug delivery systems are reviewed. The potential applications of contact lenses in point-of-care diagnostics and personalized medicine, along with the significance of integrating multiplexed sensing units together with drug delivery systems, have also been discussed.

Formulation of tunable size PLGA-PEG nanoparticles for drug delivery using microfluidic technology

Amphiphilic block co-polymer nanoparticles are interesting candidates for drug delivery as a result of their unique properties such as the size, modularity, biocompatibility and drug loading capacity. They can be rapidly formulated in a nanoprecipitation process based on self-assembly, resulting in kinetically locked nanostructures. The control over this step allows us to obtain nanoparticles with tailor-made properties without modification of the co-polymer building blocks. Furthermore, a reproducible and controlled formulation supports better predictability of a batch effectiveness in preclinical tests. Herein, we compared the formulation of PLGA-PEG nanoparticles using the typical manual bulk mixing and a microfluidic chip-assisted nanoprecipitation. The particle size tunability and controllability in a hydrodynamic flow focusing device was demonstrated to be greater than in the manual dropwise addition method. We also analyzed particle size and encapsulation of fluorescent compounds, using the common bulk analysis and advanced microscopy techniques: Transmission Electron Microscopy and Total Internal Reflection Microscopy, to reveal the heterogeneities occurred in the formulated nanoparticles. Finally, we performed in vitro evaluation of obtained NPs using MCF-7 cell line. Our results show how the microfluidic formulation improves the fine control over the resulting nanoparticles, without compromising any appealing property of PLGA nanoparticle. The combination of microfluidic formulation with advanced analysis methods, looking at the single particle level, can improve the understanding of the NP properties, heterogeneities and performance.

Cell surface nucleolin as active bait for nanomedicine in cancer therapy: a promising option

Conventional chemotherapy used against cancer is mostly limited due to their non-targeted nature, affecting normal tissue and causing undesirable toxic effects to the affected tissue. With the aim of improving these treatments both therapeutically and in terms of their safety, numerous studies are currently being carried out using nanoparticles (NPs) as a vector combining tumor targeting and carrying therapeutic tools. In this context, it appears that nucleolin, a molecule over-expressed on the surface of tumor cells, is an interesting therapeutic target. Several ligands, antagonists of nucleolin of various origins, such as AS1411, the F3 peptide and the multivalent pseudopeptide N6L have been developed and studied as therapeutic tools against cancer. Over the last ten years or so, numerous studies have been published demonstrating that these antagonists can be used as tumor targeting agents with NPs from various origins. Focusing on nucleolin ligands, the aim of this article is to review the literature recently published or under experimentation in our research team to evaluate the efficacy and future development of these tools as anti-tumor agents.

Multifunctional PLGA nanoparticles combining transferrin-targetability and pH-stimuli sensitivity enhanced doxorubicin intracellular delivery and in vitro antineoplastic activity in MDR tumor cells

Targeted delivery aims to enhance cellular uptake and improve therapeutic outcome with higher disease specificity. The expression of transferrin receptor (TfR) is upregulated on tumor cells, which make the protein Tf and its receptor vastly relevant when applied to targeting strategies. Here, we proposed Tf-decorated pH-sensitive PLGA nanoparticles containing the chemosensitizer poloxamer as a carrier for doxorubicin delivery to tumor cells (Tf-DOX-PLGA-NPs), aiming at alleviating multidrug resistance (MDR). We performed a range of in vitro studies to assess whether targeted NPs have the ability to improve DOX antitumor potential on resistant NCI/ADR-RES cells. All evaluations of the Tf-decorated NPs were performed comparatively to the nontargeted counterparts, aiming to evidence the real role of NP surface functionalization, along with the benefits of pH-sensitivity and poloxamer, in the improvement of antiproliferative activity and reversal of MDR. Tf-DOX-PLGA-NPs induced higher number of apoptotic events and ROS generation, along with cell cycle arrest. Moreover, they were efficiently internalized by NCI/ADR-RES cells, increasing DOX intracellular accumulation, which supports the greater cell killing ability of these targeted NPs with respect to MDR cells. Altogether, these findings supported the effectiveness of the Tf-surface modification of DOX-PLGA-NPs for an improved antiproliferative activity. Therefore, our pH-responsive Tf-inspired NPs are a promising smart drug delivery system to overcome MDR effect at some extent, enhancing the efficacy of DOX antitumor therapy.

Surface Functionalization of PLGA Nanoparticles to Increase Transport across the BBB for Alzheimer’s Disease

Alzheimer’s disease (AD) is a chronic neurodegenerative disorder that accounts for about 60% of all diagnosed cases of dementia worldwide. Although there are currently several drugs marketed for its treatment, none are capable of slowing down or stopping the progression of AD. The role of the blood-brain barrier (BBB) plays a key role in the design of a successful treatment for this neurodegenerative disease. Nanosized particles have been proposed as suitable drug delivery systems to overcome BBB with the purpose of increasing bioavailability of drugs in the brain. Biodegradable poly (lactic-co-glycolic acid) nanoparticles (PLGA-NPs) have been particularly regarded as promising drug delivery systems as they can be surface-tailored with functionalized molecules for site-specific targeting. In this review, a thorough discussion about the most recent functionalization strategies based on PLGA-NPs for AD and their mechanisms of action is provided, together with a description of AD pathogenesis and the role of the BBB in brain targeting.

PEGylated-PLGA Nanoparticles Coated with pH-Responsive Tannic Acid-Fe(III) Complexes for Reduced Premature Doxorubicin Release and Enhanced Targeting in Breast Cancer

Biodegradable poly(lactic-co-glycolic acid) nanoparticles (PLGA NPs) have been widely used as delivery vehicles for chemotherapy drugs. However, premature drug release in PLGA NPs can damage healthy tissue and cause serious adverse effects during systemic administration. Here, we report a tannic acid-Fe(III) (Fe^III-TA) complex-modified PLGA nanoparticle platform (DOX-TPLGA NPs) for the tumor-targeted delivery of doxorubicin (DOX). A PEGylated-PLGA inner core and Fe^III-TA complex outer shell were simultaneously introduced to reduce premature drug release in blood circulation and increase pH-triggered drug release in tumor tissue. Compared to the unmodified NPs, the initial burst rate of DOX-TPLGA NPs was significantly reduced by nearly 2-fold at pH 7.4. Moreover, the cumulative drug release rate at pH 5.0 was 40% greater than that at pH 7.4 due to the pH-response of the Fe^III-TA complex. Cellular studies revealed that the TPLGA NPs had enhanced drug uptake and superior cytotoxicity of breast cancer cells in comparison to free DOX. Additionally, the DOX-TPLGA NPs efficiently accumulated in the tumor site of 4T1-bearing nude mice due to the enhanced permeability and retention (EPR) effect and reached a tumor inhibition rate of 85.53 ± 8.77% (1.31-fold versus DOX-PLGA NPs and 3.12-fold versus free DOX). Consequently, the novel TPLGA NPs represent a promising delivery platform to enhance the safety and efficacy of chemotherapy drugs.

Facile fabrication of robust, hyaluronic acid-surfaced and disulfide-crosslinked PLGA nanoparticles for tumor-targeted and reduction-triggered release of docetaxel

It is highly tempting to develop high-efficacy targeted nanotherapeutics based on FDA approved polymers like PLGA. Herein, we describe facile fabrication of robust, hyaluronic acid-surfaced and disulfide-crosslinked star-PLGA nanoparticles (HA-sPLGA XNPs) for targeted and reduction-triggered release of docetaxel (DTX), achieving markedly enhanced treatment of A549 lung tumor in vivo. HA-sPLGA XNPs carrying 5.2 wt.% DTX (DTX-HA-sPLGA XNPs) had a size of 105.5 ± 0.5 nm and great stability while almost completely released DTX under 10 mM glutathione. Confocal and flow cytometry experiments revealed fast cellular uptake of HA-sPLGA XNPs by CD44-overexpressing A549 cells. DTX-HA-sPLGA XNPs held much higher potency to A549 cells than DTX-loaded HA-surfaced and non-crosslinked star-PLGA nanoparticles (DTX-HA-sPLGA NPs), DTX-loaded HA-surfaced and non-crosslinked linear-PLGA nanoparticles (DTX-HA-lPLGA NPs), and free DTX (IC₅₀ = 0.18 versus 0.38, 1.21 and 0.83 µg DTX equiv./mL). Intriguingly, DTX-HA-sPLGA XNPs revealed a prolonged elimination half-life of 4.18 h and notable accretion of 9.49%ID/g in A549 tumor after 8 h injection. Accordingly, DTX-HA-sPLGA XNPs demonstrated significantly better suppression of subcutaneous A549 lung tumor than DTX-HA-PLGA NPs, DTX-HA-lPLGA NPs, and free DTX controls. HA-sPLGA XNPs with low toxicity and multi-functionality appear to be a unique targeted vehicle for chemotherapy of CD44-overexpressing tumors. STATEMENT OF SIGNIFICANCE: PLGA nanoparticles with superior safety and biodegradability are among the most advanced vehicles for therapeutic delivery. The efficacy of nanomedicines based on PLGA is, however, suboptimal, due to poor tumor cell selectivity and uptake, drug leakage, and slow drug release at the pathological site. It is highly desired to develop functional PLGA nanoparticles to improve their tumor-targeting ability and therapeutic efficacy. The sophisticated fabrication and potential toxicity concerns of reported novel PLGA nanoformulations, nevertheless, preclude their clinical translation. Here, we developed hyaluronic acid-surfaced and disulfide-crosslinked star-PLGA nanoparticles (HA-sPLGA XNPs) that enabled stable encapsulation and targeted delivery of docetaxel (DTX) to CD44+ A549 lung cancer cells in vitro and in vivo, affording markedly improved tumor accumulation and repression and lower side effects compared with free DTX control. Importantly, HA-sPLGA XNPs are based on fully biocompatible materials and comparably simple to fabricate. The evident tumor targetability and safety makes HA-sPLGA XNPs a unique and potentially translatable platform for chemotherapy of CD44+ cancers.

Engineering Polymeric Nanosystems against Oral Diseases

Nanotechnology and nanoparticles (NPs) are at the forefront of modern research, particularly in the case of healthcare therapeutic applications. Polymeric NPs, specifically, hold high promise for these purposes, including towards oral diseases. Careful optimisation of the production of polymeric NPs, however, is required to generate a product which can be easily translated from a laboratory environment to the actual clinical usage. Indeed, considerations such as biocompatibility, biodistribution, and biodegradability are paramount. Moreover, a pre-clinical assessment in adequate in vitro, ex vivo or in vivo model is also required. Last but not least, considerations for the scale-up are also important, together with an appropriate clinical testing pathway. This review aims to eviscerate the above topics, sourcing at examples from the recent literature to put in context the current most burdening oral diseases and the most promising polymeric NPs which would be suitable against them.