Development of PLGA micro- and nanorods with high capacity of surface ligand conjugation for enhanced targeted delivery

Nanoparticles in liposomes: a platform for increased antibiotic selectivity in multidrug resistant bacteria in respiratory tract infections

Antibiotic resistance is a cause of serious illness and death, originating often from insufficient permeability into gram-negative bacteria. Nanoparticles (NP) can increase antibiotic delivery in bacterial cells, however, may as well increase internalization in mammalian cells and toxicity. In this work, NP in liposome (NP-Lip) formulations were used to enhance the selectivity of the antibiotics (3C and tobramycin) and quorum sensing inhibitor (HIPS-1635) towards Pseudomonas aeruginosa by fusing with bacterial outer membranes and reducing uptake in mammalian cells due to their larger size. Poly (lactic-co-glycolic) acid NPs were prepared using emulsion solvent evaporation and incorporated in larger liposomes. Cytotoxicity and uptake studies were conducted on two lung cell lines, Calu-3 and H460. NP-Lip showed lower toxicity and uptake in both cell lines. Then formulations were investigated for suitability for oral inhalation. The deposition of NP and NP-Lip in the lungs was assessed by next generation impactor and corresponded to 75% and 45% deposition in the terminal bronchi and the alveoli respectively. Colloidal stability and mucus-interaction studies were conducted. NP-Lip showed higher diffusion through mucus compared to NPs with the use of nanoparticle tracking analyzer. Moreover, the permeation of delivery systems across a liquid-liquid interface epithelial barrier model of Calu-3 cells indicated that NP-Lip could cause less systemic toxicity upon in-vivo like administration by aerosol deposition. Monoculture and Pseudomonas aeruginosa biofilm with Calu-3 cells co-culture experiments were conducted, NP-Lip achieved highest toxicity towards bacterial biofilms and least toxicity % of the Calu-3 cells. Therefore, the NP- liposomal platform offers a promising approach for enhancing antibiotic selectivity and treating pulmonary infections.

Morphological insights in oxidative sensitive nanocarrier pharmacokinetics, targeting, and photodynamic therapy

Nanoparticle (NP) morphology holds significant importance in nanomedicine, particularly concerning its implications for biological responses. This study investigates the impact of synthesizing polymers with varying degrees of methionine (MET) polymerization on three distinct drug delivery systems: spherical micelles, worm-like micelles, and vesicles, all loaded with the photosensitizer chlorin e6 (Ce6). We analyzed their distribution at both cellular and animal levels, revealing how NP morphology influences cellular uptake, subcellular localization, penetration of multicellular spheroids, blood half-life, and biodistributions across major organs. Employing a physiologically based pharmacokinetic (PBPK) model enabled us to simulate diverse distribution patterns and quantify the targeting efficiency of NPs toward tumors. Our investigation elucidates that spherical micelles exhibit lower accumulation levels within the reticuloendothelial system, potentially mitigating adverse side effects despite their higher glomerular filtration rate. This nuanced understanding underscores the complex interplay between NP morphology and biological responses, providing valuable insights into optimizing therapeutic efficacy while minimizing undesirable effects. We thus report the integration of experimental analyses with PBPK modeling to elucidate the topological characteristics of NP, thereby shedding light on their distribution patterns, therapeutic efficacy, and potential side effects.

The influence of various polymer coatings on the in vitro and in vivo properties of PLGA nanoparticles: Comprehensive study

Nanoparticles based on poly(lactic-co-glycolic acid) (PLGA) with various surface chemistry are widely used in biomedicine for theranostic applications. The nature of the external coating of nanoparticles has a significant influence on their efficiency as drug carriers or visualization agents. However, information about the mechanisms of nanoparticle accumulation in tumors and the influence of their surface properties on biodistribution is scarce due to the lack of systematic evaluation. Here we investigate the effect of different polymer coatings of the surface on in vitro and in vivo properties of PLGA nanoparticles. Namely, cell binding efficiency, cytotoxicity, efficiency of fluorescent bioimaging, and tumor accumulation were tested. The highest binding efficiency in vitro and cytotoxicity were observed for positively charged polymers. Interestingly, in vivo fluorescent visualization of tumor-bearing mice and quantitative measurements of biodistribution of magnetite-loaded nanoparticles indicated different dependences of accumulation in tumors on the coating of PLGA nanoparticles. This means that nanoparticle surface properties can simultaneously enhance imaging efficiency and decrease quantitative accumulation in tumors. The obtained data demonstrate the complexity of the dependence of nanoparticles' effectiveness for theranostic applications on surface features. We believe that this study will contribute to the rational design of nanoparticles for effective cancer diagnostics and therapy.

A microfluidic platform for the synthesis of polymer and polymer-protein-based protocells

In this study, we demonstrate the fabrication of polymersomes, protein-blended polymersomes, and polymeric microcapsules using droplet microfluidics. Polymersomes with uniform, single bilayers and controlled diameters are assembled from water-in-oil-in-water double-emulsion droplets. This technique relies on adjusting the interfacial energies of the droplet to completely separate the polymer-stabilized inner core from the oil shell. Protein-blended polymersomes are prepared by dissolving protein in the inner and outer phases of polymer-stabilized droplets. Cell-sized polymeric microcapsules are assembled by size reduction in the inner core through osmosis followed by evaporation of the middle phase. All methods are developed and validated using the same glass-capillary microfluidic apparatus. This integrative approach not only demonstrates the versatility of our setup, but also holds significant promise for standardizing and customizing the production of polymer-based artificial cells.

Assessing trans-endothelial transport of nanoparticles for delivery to abdominal aortic aneurysms

Abdominal aortic aneurysms (AAAs) are localized, rupture-prone expansions of the abdominal aorta wall. In this condition, structural extracellular matrix (ECM) proteins of the aorta wall, elastic fibers and collagen fibers, that impart elasticity and stiffness respectively, are slowly degraded by overexpressed matrix metalloproteinases (MMPs) following an injury stimulus. We are seeking to deliver therapeutics to the AAA wall using polymer nanoparticles (NPs) that are capable of stimulating on-site matrix regeneration and repair. This study aimed to determine how NP shape and size impacts endocytosis and transmigration past the endothelial cell (EC) layer from circulation into the medial layer of the AAA wall. First, rod-shaped NPs were shown to be created based mechanical stretching of PLGA NPs while embedded in a PVA film with longer rod-shaped NPs created based of the degree in which the PVA films are stretched. Live/dead assay reveals that our PLGA NPs are safe and do not cause cell death. Immunofluorescence staining reveal cytokine activation causes endothelial dysfunction in ECs by increasing expression of inflammatory marker Integrin αVβ3 and decreasing expression of adhesion protein vascular endothelial (VE)-cadherin. We showed this disruption enable greater EC uptake and translocation of NPs. Fluorescence studies demonstrate high endothelial transmigration and endocytosis with rod-shaped NPs in cytokine activated ECs compared to healthy control cells, arguing for the benefits of using higher aspect ratio (AR) NPs for accumulation at the aneurysm site. We also demonstrated that the mechanisms of NP transmigration across an activated EC layer depend on NP AR. These results show the potential of using shape as a modality for enhancing permeation of NPs into the aneurysm wall. These studies are also significance to understanding the mechanisms that are likely engaged by NPs for penetrating the endothelial lining of aneurysmal wall segments.

Multi-Functional Polymer Nanoparticles with Enhanced Adipocyte Uptake and Adipocytolytic Efficacy

Multi-functional polymer nanoparticles have been widely utilized to improve cellular uptake and enhance therapeutic efficacy. In this study, it is hypothesized that the cellular uptake of poly(D,L-lactide-co-glycolide) (PLG) nanoparticles loaded with calcium carbonate minerals into adipocytes can be improved by covalent modification with nona-arginine (R9 ) peptide. It is further hypothesized that the internalization mechanism of R9 -modified PLG nanoparticles by adipocytes may be contingent on the concentration of R9 peptide present in the nanoparticles. R9 -modified PLG nanoparticles followed the direct penetration mechanism when the concentration of R9 peptide in the nanoparticles reached 38 µM. Notably, macropinocytosis is the major endocytic mechanism when the R9 peptide concentration is ≤ 26 µM. The endocytic uptake of the nanoparticles effectively generated carbon dioxide gas at an endosomal pH, resulting in significant adipocytolytic effects in vitro, which are further supported by the findings in an obese mouse model induced by high-fat diet. Gas-generating PLG nanoparticles, modified with R9 peptide, demonstrated localized reduction of adipose tissue (reduction of 13.1%) after subcutaneous injection without significant side effects. These findings highlight the potential of multi-functional polymer nanoparticles for the development of effective and targeted fat reduction techniques, addressing both health and cosmetic considerations.

Use of nanoparticles, a modern means of drug delivery, against cryptosporidiosis

Cryptosporidium is a primary cause of waterborne epidemics, despite being previously considered only an opportunistic pathogen. The disease is associated with significant economic losses in humans and animals that are brought on by diarrhea, which frequently causes dehydration. Contact with diseased people or animals, as well as polluted water, is the major cause of infection. Different drugs are used to control the parasites. Nitazoxanide (NTZ), which is an anti-protozoan and anti-viral drug, can be used to control helminths, viruses, and protozoan parasites as a broad-spectrum antibiotic and has been approved by the food and drug authority (FDA). However, the problem is the development of resistance over a period of time in these parasites. Nanoparticles have received significant attention as possible anti-parasitic agents in recent years. By directing medications to specific cellular locations, targeted drug delivery minimizes the side effects of medications. Nanoparticles have demonstrated effectiveness against different Cryptosporidium species. Nanoparticles loaded with NTZ are found to be an effective remedy for C. parvum in young ones and decrease the oocyst count shed in the stools. Additionally, silver nanoparticles have proven to be effective against C. parvum by releasing silver ions that breach the cell wall of the oocyst, causing the escape of intracellular contents and the destruction of sporozoites within the oocyst. Implementing tiny particles for the purification of consuming water from Cryptosporidium is an economical and environmentally sustainable process. However, the use of nanoparticles in medicine requires more research.

Asymmetry-Enhanced Motion of Urease-Powered Micromotors from Double Emulsion-Templated Microcapsules

Autonomous motion of enzyme-powered motors has important implications for drug delivery, cell-cell communication, and protocell engineering. Although many of these systems are inspired by the motion of biological cells, most of them lack key structural features, like micrometer-sized boundaries and aqueous compartments, and rely on bubble propulsion to generation motion. In this study, we use droplet microfluidics to generate large populations of cell-sized microcapsules with poly(lactic-co-glycolic acid) shells and functionalize their surfaces with the enzyme urease to drive their motion. We adjust the number of surface functional groups for urease conjugation by preparing microcapsules with two different surfactants, poly(vinyl alcohol) (PVA) and poly(ethylene-alt-maleic anhydride) (PEMA). We also tune the surface roughness of the microcapsules by varying the concentration of silica nanoparticles in the droplet middle phase. We find that PEMA plays a crucial role in increasing the grafting density of urease on the surface of smooth microcapsules, leading to active motion in the presence of urea. In addition, rough microcapsules prepared with PEMA and loaded with comparable amounts of urease move up to three times faster than their smooth counterparts, which we believe is due to an asymmetric distribution of urease on the surface, giving rise to a preferred direction of motion. Taken together, these results provide new insights into the role that various stabilizing agents play in the induction of motion by enzymatic motors prepared from microfluidics, which is a potentially powerful tool for future preparation of motile protocells in biomedicine.

Review on PLGA Polymer Based Nanoparticles with Antimicrobial Properties and Their Application in Various Medical Conditions or Infections

The rise in the resistance to antibiotics is due to their inappropriate use and the use of a broad spectrum of antibiotics. This has also contributed to the development of multidrug-resistant microorganisms, and due to the unavailability of suitable new drugs for treatments, it is difficult to control. Hence, there is a need for the development of new novel, target-specific antimicrobials. Nanotechnology, involving the synthesis of nanoparticles, may be one of the best options, as it can be manipulated by using physicochemical properties to develop intelligent NPs with desired properties. NPs, because of their unique properties, can deliver drugs to specific targets and release them in a sustained fashion. The chance of developing resistance is very low. Polymeric nanoparticles are solid colloids synthesized using either natural or synthetic polymers. These polymers are used as carriers of drugs to deliver them to the targets. NPs, synthesized using poly-lactic acid (PLA) or the copolymer of lactic and glycolic acid (PLGA), are used in the delivery of controlled drug release, as they are biodegradable, biocompatible and have been approved by the USFDA. In this article, we will be reviewing the synthesis of PLGA-based nanoparticles encapsulated or loaded with antibiotics, natural products, or metal ions and their antibacterial potential in various medical applications.

The Autoinducer N-Octanoyl-L-Homoserine Lactone (C8-HSL) as a Potential Adjuvant in Vaccine Formulations

Autoinducers AI-1 and AI-2 play an important role in bacterial quorum sensing (QS), a form of chemical communication between bacteria. The autoinducer N-octanoyl-L-Homoserinehomoserine lactone (C8-HSL) serves as a major inter- and intraspecies communicator or 'signal', mainly for Gram-negative bacteria. C8-HSL is proposed to have immunogenic properties. The aim of this project is to evaluate C8-HSL as a potential vaccine adjuvant. For this purpose, a microparticulate formulation was developed. The C8-HSL microparticles (MPs) were formulated by a water/oil/water (W/O/W) double-emulsion solvent evaporation method using PLGA (poly (lactic-co-glycolic acid)) polymer. We tested C8-HSL MPs with two spray-dried bovine serum albumin (BSA)-encapsulated bacterial antigens: colonization factor antigen I (CFA/I) from Escherichia coli (E. coli.) and the inactive protective antigen (PA) from Bacillus anthracis (B. anthracis). We formulated and tested C8-HSL MP to determine its immunogenicity potential and its ability to serve as an adjuvant with particulate vaccine formulations. An in vitro immunogenicity assessment was performed using Griess's assay, which indirectly measures the nitric oxide radical (NOˑ) released by dendritic cells (DCs). The C8-HSL MP adjuvant was compared with FDA-approved adjuvants to determine its immunogenicity potential. C8-HSL MP was combined with particulate vaccines for measles, Zika and the marketed influenza vaccine. The cytotoxicity study showed that MPs were non-cytotoxic toward DCs. Griess's assay showed a comparable release of NOˑ from DCs when exposed to CFA and PA bacterial antigens. Nitric oxide radical (NOˑ) release was significantly higher when C8-HSL MPs were combined with particulate vaccines for measles and Zika. C8-HSL MPs showed immunostimulatory potential when combined with the influenza vaccine. The results showed that C8-HSL MPs were as immunogenic as FDA-approved adjuvants such as alum, MF59, and CpG. This proof-of-concept study showed that C8-HSL MP displayed adjuvant potential when combined with several particulate vaccines, indicating that C8-HSL MPs can increase the immunogenicity of both bacterial and viral vaccines.

Core-Shell Structured PLGA Particles Having Highly Controllable Ketoprofen Drug Release

The non-steroid anti-inflammatory drug ketoprofen (KP) as a model molecule is encapsulated in different poly(lactide-co-glycolide) (PLGA) nanostructured particles, using Tween20 (TWEEN) and Pluronic F127 (PLUR) as stabilizers to demonstrate the design of a biocompatible colloidal carrier particles with highly controllable drug release feature. Based on TEM images the formation of well-defined core-shell structure is highly favorable using nanoprecipitation method. Stabile polymer-based colloids with ~200-210 nm hydrodynamic diameter can be formed by successful optimization of the KP concentration with the right choice of stabilizer. Encapsulation efficiency (EE%) of 14-18% can be achieved. We clearly confirmed that the molecular weight of the stabilizer thus its structure greatly controls the drug release from the PLGA carrier particles. It can be determined that ~20% and ~70% retention is available with the use of PLUR and TWEEN, respectively. This measurable difference can be explained by the fact that the non-ionic PLUR polymer provides a steric stabilization of the carrier particles in the form of a loose shell, while the adsorption of the non-ionic biocompatible TWEEN surfactant results in a more compact and well-ordered shell around the PLGA particles. In addition, the release property can be further tuned by decreasing the hydrophilicity of PLGA by changing the monomer ratio in the range of ~20-60% (PLUR) and 70-90% (TWEEN).

Effects of Particle Geometry for PLGA-Based Nanoparticles: Preparation and In Vitro/In Vivo Evaluation

The physicochemical properties (size, shape, zeta potential, porosity, elasticity, etc.) of nanocarriers influence their biological behavior directly, which may result in alterations of the therapeutic outcome. Understanding the effect of shape on the cellular interaction and biodistribution of intravenously injected particles could have fundamental importance for the rational design of drug delivery systems. In the present study, spherical, rod and elliptical disk-shaped PLGA nanoparticles were developed for examining systematically their behavior in vitro and in vivo. An important finding is that the release of the encapsulated human serum albumin (HSA) was significantly higher in spherical particles compared to rod and elliptical disks, indicating that the shape can make a difference. Safety studies showed that the toxicity of PLGA nanoparticles is not shape dependent in the studied concentration range. This study has pioneering findings on comparing spherical, rod and elliptical disk-shaped PLGA nanoparticles in terms of particle size, particle size distribution, colloidal stability, morphology, drug encapsulation, drug release, safety of nanoparticles, cellular uptake and biodistribution. Nude mice bearing non-small cell lung cancer were treated with 3 differently shaped nanoparticles, and the accumulation of nanoparticles in tumor tissue and other organs was not statistically different (p > 0.05). It was found that PLGA nanoparticles with 1.00, 4.0 ± 0.5, 7.5 ± 0.5 aspect ratios did not differ on total tumor accumulation in non-small cell lung cancer.

Neuro-nanotechnology: diagnostic and therapeutic nano-based strategies in applied neuroscience

Artificial, de-novo manufactured materials (with controlled nano-sized characteristics) have been progressively used by neuroscientists during the last several decades. The introduction of novel implantable bioelectronics interfaces that are better suited to their biological targets is one example of an innovation that has emerged as a result of advanced nanostructures and implantable bioelectronics interfaces, which has increased the potential of prostheses and neural interfaces. The unique physical-chemical properties of nanoparticles have also facilitated the development of novel imaging instruments for advanced laboratory systems, as well as intelligently manufactured scaffolds and microelectrodes and other technologies designed to increase our understanding of neural tissue processes. The incorporation of nanotechnology into physiology and cell biology enables the tailoring of molecular interactions. This involves unique interactions with neurons and glial cells in neuroscience. Technology solutions intended to effectively interact with neuronal cells, improved molecular-based diagnostic techniques, biomaterials and hybridized compounds utilized for neural regeneration, neuroprotection, and targeted delivery of medicines as well as small chemicals across the blood-brain barrier are all purposes of the present article.

Preparation and optimization of poly (lactic-co-glycolic acid) rod-shaped particles in nano size range for paclitaxel delivery

Nanoparticle shape has been acknowledged as an important design parameter due to its influence on nanoparticle interaction with biological systems. However, there is lacking of simple and scalable preparation technique for drug loaded non-spherical polymeric nanoparticles for a long time, thus hindering the potential applications. Although our previous research has modified the traditional emulsion solvent evaporation technique by adding guest molecules to prepare non-spherical poly (lactic-co-glycolic acid) (PLGA) particles, it is difficult to obtain nano-sized rods with minor axis less than 200 nm, which may have great potential in cancer therapy. Herein, in present research, the two-step ESE method was used and optimized to prepare poly (lactic-co-glycolic acid) nanorods for paclitaxel delivery. Firstly, the single-factor experiment was used to screen the influence of multi-factors including type of guest molecules, concentration of guest molecules, emulsification method, surfactant concentration, oil volume, poly (lactic-co-glycolic acid) concentration on the size and shape to determine the range of variables; based on the above range, a multi-factor and multi-level orthogonal experiment was designed. The formula is evaluated by the rod fabrication yield and the aspect ratio of major axis to minor axis. The results showed that the yield of nanorods in the optimal formula was 99% and the aspect ratio was 5.35 ± 2.05 with the minor axis of 135.49 ± 72.66 nm, and major axis of 657.77 ± 307.63 nm. In addition, the anti-cancer drug paclitaxel was successfully encapsulated in PLGA nanorods by the same technique. Our results not only enrich the ESE technique for preparing small sized poly (lactic-co-glycolic acid) nanorods, but also envision the potential application of nanorods for targeted cancer therapy with the delivery of paclitaxel.

Preparation of Surface-Supported Polylactide Spherical-Cap Particles

Biodegradable polymer particles are of considerable importance due to their multiple applications in medical diagnostics and therapy. Spherical-cap particles have been prepared in a very general and simple method by melting a thin polymer film supported on a solid substrate that is in contact with a hydrophilic solvent. The melted polymer forms droplets which transform into solid particles attached to the surface after cooling down the sample. This approach has been demonstrated for polylactide adlayers on glass, which, when melted in glycerol, produce an array of polymer particles supported on the surface. The size of the particles depends on the experimental conditions and ranges from tens of nanometers to several micrometers. The particles can be employed to incorporate guest species, for example, drug molecules or inorganic nanoparticles. This has been confirmed herein through entrapment of an anticancer drug (doxorubicin) and radiogold (Au-198) nanoparticles. The resulting structures have been examined using a number of complementary physicochemical techniques including scanning and transmission electron microscopy, atomic force and optical microscopy as well as Raman and fluorescence spectroscopy.

Bacteria-Adhesive Nitric Oxide-Releasing Graphene Oxide Nanoparticles for MRPA-Infected Wound Healing Therapy

A bacteria-infected wound can lead to being life-threatening and raises a great economic burden on the patient. Here, we developed polyethylenimine 1.8k (PEI_1.8k) surface modified NO-releasing polyethylenimine 25k (PEI_25k)-functionalized graphene oxide (GO) nanoparticles (GO-PEI_25k/NO-PEI_1.8k NPs) for enhanced antibacterial activity and infected wound healing via binding to the bacterial surface. In vitro antibacterial activity and in vivo wound healing efficacy in an infected wound model were evaluated compared with NO-releasing NPs (GO-PEI_25k/NO NPs). Surface modification with PEI_1.8k can enhance the ability of nanoparticles to adhere to bacteria. GO-PEI_25k/NO-PEI_1.8k NPs released NO in a sustained manner for 48 h and exhibited the highest bactericidal activity (99.99% killing) against methicillin-resistant Staphylococcus aureus (MRSA) and multidrug-resistant Pseudomonas aeruginosa (MRPA) without cytotoxicity to L929 mouse fibroblast cells at 0.1 mg/mL. In the MRPA-infected wound model, GO-PEI_25k/NO-PEI_1.8k NPs showed 87% wound size reduction while GO-PEI_25k/NO NPs showed 23% wound size reduction at 9 days postinjury. Masson trichrome and hematoxylin and eosin staining revealed that GO-PEI_25k/NO-PEI_1.8k NPs enhanced re-epithelialization and collagen deposition, which are comparable to healthy mouse skin tissue. GO-PEI_25k/NO-PEI_1.8k NPs hold promise as effective antibacterial and wound healing agents.

Facile Fabrication of Starch-Based Microrods by Shear-Assisted Antisolvent-Induced Nanoprecipitation and Solidification

Rod-like particles have attracted increasing attention because of their unique shape-dependent properties, which enable their superior performance compared to their isotropic counterparts. Thus, rod-like particles have potential applications in many fields, especially in biomedicine. However, the fabrication of uniform rod-like particles is challenging because of the principle of interfacial energy minimization. Herein, we present a facile, rapid, and cost-effective strategy for preparing starch-based microrods with tunable aspect ratios via shear-assisted antisolvent-induced nanoprecipitation and solidification. The preformed spherical particles swollen by the mixed solvent were elongated by the shear force and solidified in rod-like shape by antisolvent induction. The resulting starch-based microrods can encapsulate hydrophobic active substances and be modified with functional groups, indicating their potential applications as drug carriers and biologically active materials. The formation mechanism of the starch-based microrods discovered in this study provides a new perspective on the fabrication of rod-like polymer particles.

Nanotechnology based drug delivery systems: Does shape really matter?

As of today, the era of nanomedicine has brought numerous breakthroughs and overcome challenges in the treatment of various disorders. Various factors like size, charge and surface hydrophilicity have garnered significant attention by nanotechnologists. However, more exploration in the field of nanoparticle shape and geometry, one of the basic physical phenomenon is required. Tuning nanoparticle shape and geometry could potentially overcome pitfalls in therapeutics and biomedical fields. Thus, in this article, we unveil the importance of tuning nanoparticle shape selection across the delivery platforms. This article provides an in-depth understanding of nanoparticle shape modulation and advise the researchers on the ideal morphology selection tailored for each implication. We deliberated the importance of nanoparticle shape selection for specific implications with respect to organ targeting, cellular internalization, pharmacokinetics and bio-distribution, protein corona formation as well as RES evasion and tumor targeting. An additional section on the significance of shape transformation, a recently introduced novel avenue with applications in drug delivery was discussed. Furthermore, regulatory concerns towards nanoparticle shape which need to be addressed for harnessing their clinical translation will be explained.

Induction of Peptide-specific CTL Activity and Inhibition of Tumor Growth Following Immunization with Nanoparticles Coated with Tumor Peptide-MHC-I Complexes

Tumor peptides associated with MHC class I molecules or their synthetic variants have attracted great attention for their potential use as vaccines to induce tumor-specific CTLs. However, the outcome of clinical trials of peptide-based tumor vaccines has been disappointing. There are various reasons for this lack of success, such as difficulties in delivering the peptides specifically to professional Ag-presenting cells, short peptide half-life in vivo, and limited peptide immunogenicity. We report here a novel peptide vaccination strategy that efficiently induces peptide-specific CTLs. Nanoparticles (NPs) were fabricated from a biodegradable polymer, poly(D,L-lactic-co-glycolic acid), attached to H-2K^b molecules, and then the natural peptide epitopes associated with the H-2K^b molecules were exchanged with a model tumor peptide, SIINFEKL (OVA_257-268). These NPs were efficiently phagocytosed by immature dendritic cells (DCs), inducing DC maturation and activation. In addition, the DCs that phagocytosed SIINFEKL-pulsed NPs potently activated SIINFEKL-H-2K^b complex-specific CD8⁺ T cells via cross-presentation of SIINFEKL. In vivo studies showed that intravenous administration of SIINFEKL-pulsed NPs effectively generated SIINFEKL-specific CD8⁺ T cells in both normal and tumor-bearing mice. Furthermore, intravenous administration of SIINFEKL-pulsed NPs into EG7.OVA tumor-bearing mice almost completely inhibited the tumor growth. These results demonstrate that vaccination with polymeric NPs coated with tumor peptide-MHC-I complexes is a novel strategy for efficient induction of tumor-specific CTLs.

Effect of Formulation Variables for the Production of WGA-Grafted, Levodopa-Loaded PLGA Nanoparticles

Levodopa is used for the treatment of Parkinson’s disease (PD) for the last few decades. However, adverse reactions such as dyskinesia, somnolence, nausea, itching, rash, as well as the need for frequent dosing and low bioavailability problems affect the success of the treatment. To prevent side effects caused by conventional therapy, a nanoparticular drug delivery system has been developed, in which receptors are constantly stimulated, and the frequency of dosing is reduced. In this study, levodopa was loaded in Poly lactic-co-glycolic acid (PLGA) nanoparticles (NP) which modified with Wheat Germ Agglutinin (WGA) To increase the effectiveness of levodopa, reduce its side effects and apply to the nasal area which is an alternative way for brain targeting with lower doses. To obtain the optimum levodopa loaded PLGA nanoparticles, the effect of some formulation variables such as polyvinyl alcohol (PVA) concentration, homogenization speed, polymer amount and molecular weight, and levodopa content on the entrapment efficiency (EE) and particle size of the nanoparticles were investigated. Besides these variables, the effect of different parameters on the WGA binding constant was also searched. In addition to in vitro release studies, Differential Scanning Calorimetry (DSC) and Fourier Transform Infrared Spectrophotometer (FT-IR), and Transmission electron microscopy (TEM) analysis were used in the characterization of nanoparticles. Among all formulations, A2 and A8a which was produced with different molcular weights of PLGA, different added levodopa amounts and with different homogenization speeds were chosen as optimum formulations due to their sustained release properties and the ability to release 80 % of their drug content.WGA binding constant was found 78.20 % for A8a-1 and 95 % for A2-1. In this study, we aimed to determine the effect of different formulation parameters on the development of levodopa loaded and WGA grafted PLGA nanoparticles and on the quality characteristics of nanoparticle formulations such as particle size, zeta potential, and EE. In this paper, our results are demonstrated for a better understanding of the effect of process parameters on the development of nanoparticle-based drug delivery systems by using the double-emulsion solvent evaporation technique and on WGA binding of drug-loaded PLGA nanoparticles.

Diethylenetriamine/NONOate-doped alginate hydrogel with sustained nitric oxide release and minimal toxicity to accelerate healing of MRSA-infected wounds

This study demonstrates the development of a nitric oxide (NO)-releasing hydrogel wound dressing and its efficacy at accelerating methicillin-resistant Staphylococcus aureus (MRSA)-infected wound healing. A DETA/NONOate-doped alginate (Alg-DETA/NO) hydrogel was synthesized using alginate as a hydrogel-forming wound dressing material and diethylenetriamine/diazeniumdiolate (DETA/NONOate) as an NO donor. Alg-DETA/NO exhibited a prolonged NO release profile over a period of 4 days. The rheological properties of Alg-DETA/NO did not differ significantly from those of pure alginate. Importantly, Alg-DETA/NO showed potent antibacterial activity against MRSA, with minimal toxicity to mouse fibroblasts. The application of Alg-DETA/NO to MRSA-infected wounds in a mouse model showed a favorable wound healing with accelerated wound-size reduction and reduced skin bacterial infection. Additionally, histological examination revealed that Alg-DETA/NO reduced inflammation at the wound site and promoted re-epithelialization, angiogenesis, and collagen deposition. Thus, Alg-DETA/NO presented herein could serve as a safe and potent hydrogel dressing for the treatment of MRSA-infected wounds.

Brigatinib loaded poly(d,l-lactide-co-glycolide) nanoparticles for improved anti-tumoral activity against non-small cell lung cancer cell lines

OBJECTIVE

The aim of the current investigation was to develop poly(d,l-lactide-co-glycolide) (PLGA) nanoparticles (NPs) to sustain the brigatinib (BTB) release for prolong time period and to examine the antitumor effect of the optimized NPs.

SIGNIFICANCE

Optimized PLGA-based NPs of BTB could be potentially used as a promising nanocarrier for the treatment of non-small cell lung cancer.

METHODS

BTB-loaded NPs were fabricated with core-shell of PLGA by solvent evaporation technique using different proportions of PLGA polymer and poly-vinyl alcohol (PVA) stabilizer. The prepared NPs were evaluated for particle characterizations; size, polydispersity index (PDI), zeta-potential, entrapment efficiency (EE), and drug loading (DL), Fourier-transform infrared (FTIR) spectroscopy, differential scanning calorimetry (DSC), and X-ray diffraction studies. The optimized NPs (BN5) were further evaluated for morphology, stability, and cytotoxicity studies against A549 cell-lines.

RESULTS

Among the nine different NPs formulae (BN1-BN9), BN5 was optimized with composition of BTB (30 mg), PLGA (75 mg), PVA (0.55% w/v), represents an average particle size of (267.1 ± 1.01 nm), PDI (0.101 ± 0.007), and zeta potential (-42.1 ± 0.75 mV), high EE (66.83 ± 0.06%), and DL (6.17 ± 0.69%). SEM image of selected NPs was spherical with smooth surface. In vitro drug release profile in phosphate buffers (pH 5 and pH 7.4) showed a biphasic release with initial burst phase followed by sustained release for prolong time. Furthermore, optimized NPs (BN5) exhibited excellent cytotoxic activity against A549 cell-lines with IC₅₀ value of 5.25 ± 0.23 µg/mL.

CONCLUSION

The overall results suggest that BTB-loaded PLGA NPs could be a potential nanocarrier for lung cancer treatment.

Non-spherical micro- and nanoparticles for drug delivery: Progress over 15 years

Shape of particulate drug carries has been identified as a key parameter in determining their biological outcome. In this review, we analyze the field of particle shape as it shifts from fundamental investigations to contemporary applications for disease treatment, while highlighting outstanding remaining questions. We summarize fabrication and characterization methods and discuss in depth how particle shape influences biological interactions with cells, transport in the vasculature, targeting in the body, and modulation of the immune response. As the field moves from discoveries to applications, further attention needs to be paid to factors such as characterization and quality control, selection of model organisms, and disease models. Taken together, these aspects will provide a conceptual foundation for designing future non-spherical drug carriers to overcome biological barriers and improve therapeutic efficacy.

Fabrication and evaluation of artemether loaded polymeric nanorods obtained by mechanical stretching of nanospheres

The objective of the present study was to prepare and evaluate artemether-loaded poly (lactic-co-glycolic acid) (PLGA) nanorods by mechanical stretching of nanospheres. Artemether-loaded PLGA nanospheres were prepared by the standard nanoprecipitation method. To prepare the nanorods, nanospheres (129 nm) were embedded in polyvinyl alcohol film. The film was stretched by using an in-house fabricated film stretching apparatus in one dimension at the rate of 10 mm/min in acetone or silicon oil. Nanorods were recovered by dissolving the film in Milli-Q-water after stretching. The effect of film thickness (100 µm vs 150 µm), the ratio of lactide to glycolide in PLGA (50:50 vs 75:25), extent of stretching (2x vs 4x), on the aspect ratio of the nanorods was studied. A sustained release of artemether was observed from both nanospheres and nanorods with almost 85% drug release at the end of 72 h. In cytotoxicity study, almost 90% cell viability was found when THP-1 cells were treated with artemether, nanospheres, and nanorods equivalent to 0.001 to 100 µg/mL of artemether. At all the concentrations of artemether, nanorods showed less haemolysis of RBCs than the nanospheres. Artemether-loaded PLGA nanorods could be successfully prepared by the film stretching method for intravenous delivery of antimalarial drugs.

Functionalized Particles Designed for Targeted Delivery

Pure bioactive compounds alone can only be exceptionally administered in medical treatment. Usually, drugs are produced as various forms of active compounds and auxiliary substances, combinations assuring the desired healing functions. One of the important drug forms is represented by a combination of active substances and particle-shaped polymer in the nano- or micrometer size range. The review describes recent progress in this field balanced with basic information. After a brief introduction, the paper presents a concise overview of polymers used as components of nano- and microparticle drug carriers. Thereafter, progress in direct synthesis of polymer particles with functional groups is discussed. A section is devoted to formation of particles by self-assembly of homo- and copolymer-bearing functional groups. Special attention is focused on modification of the primary functional groups introduced during particle preparation, including introduction of ligands promoting anchorage of particles onto the chosen living cell types by interactions with specific receptors present in cell membranes. Particular attention is focused on progress in methods suitable for preparation of particles loaded with bioactive substances. The review ends with a brief discussion of the still not answered questions and unsolved problems.

Quantitative comparison of different fluorescent dye-loaded nanoparticles

Labeling nanoparticles with fluorescent dyes is a common approach to investigate their cell uptake and biodistribution, providing valuable information for the preclinical assessment of nanoparticles for drug delivery. However, the underlying assumption that the fluorescence intensity of dye-labeled nanoparticles correlates positively with the amount of nanoparticles taken up by cells might not be valid under some conditions, as it can be affected by many factors including dye dispersion, dye quenching, and material shading. Here we demonstrated that both nanoparticles with hydrophobic dyes encapsulated inside and nanoparticles with hydrophilic dyes conjugated on the particle surface suffer from different degrees of dye quenching, making it challenging for quantitative comparison of cell uptake of different nanoparticles. To address this challenge, we proposed a possible solution for direct comparative studies of dye-labeled nanoparticles. This work provides valuable information for designing and evaluating different nanoparticles for drug delivery applications.

Ferulic Acid-Loaded Polymeric Nanoparticles for Potential Ocular Delivery

Ferulic acid (FA) is an antioxidant compound that can prevent ROS-related diseases, but due to its poor solubility, therapeutic efficacy is limited. One strategy to improve the bioavailability is nanomedicine. In the following study, FA delivery through polymeric nanoparticles (NPs) consisting of polylactic acid (NPA) and poly(lactic-co-glycolic acid) (NPB) is proposed. To verify the absence of cytotoxicity of blank carriers, a preliminary in vitro assay was performed on retinal pericytes and endothelial cells. FA-loaded NPs were subjected to purification studies and the physico-hemical properties were analyzed by photon correlation spectroscopy. Encapsulation efficiency and in vitro release studies were assessed through high performance liquid chromatography. To maintain the integrity of the systems, nanoformulations were cryoprotected and freeze-dried. Morphology was evaluated by a scanning electron microscope. Physico-chemical stability of resuspended nanosystems was monitored during 28 days of storage at 5 °C. Thermal analysis and Fourier-transform infrared spectroscopy were performed to characterize drug state in the systems. Results showed homogeneous particle populations, a suitable mean size for ocular delivery, drug loading ranging from 64.86 to 75.16%, and a controlled release profile. The obtained systems could be promising carriers for ocular drug delivery, legitimating further studies on FA-loaded NPs to confirm efficacy and safety in vitro.

Colitis-targeted hybrid nanoparticles-in-microparticles system for the treatment of ulcerative colitis

Nanoparticle (NP)-based drug delivery systems accumulate in the disrupted epithelium of inflamed colon tissue in ulcerative colitis. However, premature early drug release and uptake or degradation of NPs during their passage through the harsh gastric or intestinal environment compromise their therapeutic outcomes. This study aimed to develop an advanced colitis-targeted hybrid nanoparticles-in-microparticles (NPsinMPs) drug delivery system to overcome the aforementioned challenges. First, sustained drug releasing poly(lactic-co-glycolic acid) NPs were generated and further encapsulated in pH-sensitive Eudragit FS30D MPs to ensure complete drug protection in a gastric-like pH and for selective delivery of NPs to the colon. SEM and confocal microscopy for the NPsinMPs revealed successful NP encapsulation. NPsinMPs prevented drug release in an acidic gastric-like and intestinal-like pH and presented a sustained release thereafter at an ileal and colonic pH, indicating the degradation of the outer pH-sensitive MPs and release of NPs. Furthermore, in vivo imaging of gastrointestinal tract of a colitis mouse orally administered with fluorescent NPsinMPs revealed higher fluorescence intensities selectively in the colon, demonstrating the release of loaded NPs and their concomitant accumulation at the site of colon inflammation. NPsinMPs markedly mitigated experimental colitis in mice indicated by improved histopathological analysis, decreased myeloperoxidase activity, neutrophils and macrophage infiltration, and expression of proinflammatory cytokines in colonic tissues compared with NP-treated mice. The present results show the successful formulation of an NPsinMP-based drug delivery system and provide a platform to improve NP-based colon-targeted drug delivery through improved protection of encapsulated NPs and their payload in the early small intestine.

Design and evaluation of the anticancer activity of paclitaxel-loaded anisotropic-poly(lactic-co-glycolic acid) nanoparticles with PEGylated chitosan surface modifications

This study aimed to evaluate the anticancer activity of paclitaxel-loaded poly(lactic-co-glycolic acid) (PLGA) nanoparticles (PNPs) based on their shapes and surface modifications in breast cancer cells. We hypothesized that anisotropic-PNPs (AT-PNPs) with PEGylated chitosan (CP) surface modifications and high aspect ratios exhibit higher anticancer activity than PNPs and AT-PNPs with CP surface modifications and low aspect ratios. Six types of PNPs and AT-PNPs with different shapes and surface modifications were successfully prepared. The cellular uptake and cytotoxicity of the AT-PNPs were higher than those of the PNPs, while the cellular uptake and cytotoxicity of the PNPs and AT-PNPs with CP were higher than those of the uncoated PNPs and AT-PNPs. Moreover, all the particles remained stable for 4 months. In conclusion, this study primarily described the preparation of CP-AT-PNPs, and the CP-AT-PNPs2 developed herein are expected to demonstrate promising anticancer effects in animal experiments and clinical studies.

Nanotechnology approaches in the current therapy of skin cancer

Skin cancer is a high burden disease with a high impact on global health. Conventional therapies have several drawbacks; thus, the development of effective therapies is required. In this context, nanotechnology approaches are an attractive strategy for cancer therapy because they enable the efficient delivery of drugs and other bioactive molecules to target tissues with low toxic effects. In this review, nanotechnological tools for skin cancer will be summarized and discussed. First, pathology and conventional therapies will be presented, followed by the challenges of skin cancer therapy. Then, the main features of developing efficient nanosystems will be discussed, and next, the most commonly used nanoparticles (NPs) described in the literature for skin cancer therapy will be presented. Subsequently, the use of NPs to deliver chemotherapeutics, immune and vaccine molecules and nucleic acids will be reviewed and discussed as will the combination of physical methods and NPs. Finally, multifunctional delivery systems to codeliver anticancer therapeutic agents containing or not surface functionalization will be summarized.

Bacteria-Targeted Clindamycin Loaded Polymeric Nanoparticles: Effect of Surface Charge on Nanoparticle Adhesion to MRSA, Antibacterial Activity, and Wound Healing

Adhesion of nanoparticles (NPs) to the bacterial cell wall by modifying their physicochemical properties can improve the antibacterial activity of antibiotic. In this study, we prepared positively charged clindamycin-loaded poly (lactic-co-glycolic acid)-polyethylenimine (PLGA-PEI) nanoparticles (Cly/PPNPs) and negatively charged clindamycin-loaded PLGA NPs (Cly/PNPs) and investigated the effect of NP adhesion to bacteria on the treatment of methicillin-resistant Staphylococcus aureus (MRSA)-infected wounds. The Cly/PPNPs and Cly/PNPs were characterized according to particle size, polydispersity index, surface charge, and drug loading. Both Cly/PPNPs and Cly/PNPs exhibited sustained drug release over 2 days. The Cly/PPNPs bind to the MRSA surface, thereby enhancing bactericidal efficacy against MRSA compared with the Cly/PNPs. Furthermore, compared with other groups, Cly/PPNPs significantly accelerated the healing and re-epithelialization of wounds in a mouse model of a MRSA-infected wounds. We also found that both NPs are harmless to healthy fibroblast cells. Therefore, our results suggest that the Cly/PPNPs developed in this study improve the efficacy of clindamycin for the treatment of MRSA-infected wounds.

PEI/NONOates-doped PLGA nanoparticles for eradicating methicillin-resistant Staphylococcus aureus biofilm in diabetic wounds via binding to the biofilm matrix

Wounds infected with methicillin-resistant Staphylococcus aureus (MRSA) biofilm represent a high risk in patients with diabetes. Nitric oxide (NO) has shown promise in dispersing biofilm and wound healing. For an effective treatment of MRSA biofilm-infected wounds, however, NO needs to be supplied to the biofilm matrix in a sustainable manner due to a short half-life and limited diffusion distance of NO. In this study, polyethylenimine/diazeniumdiolate (PEI/NONOate)-doped PLGA nanoparticles (PLGA-PEI/NO NPs) with an ability to bind to the biofilm matrix are developed to facilitate the NO delivery to MRSA biofilm-infected wound. In simulated wound fluid, PLGA-PEI/NO NPs show an extended NO release over 4 days. PLGA-PEI/NO NPs firmly bind to the MRSA biofilm matrix, resulting in a greatly enhanced anti-biofilm activity. Moreover, PLGA-PEI/NO NPs accelerate healing of MRSA biofilm-infected wounds in diabetic mice along with complete biofilm dispersal and reduced bacterial burden. These results suggest that the biofilm-binding NO-releasing NPs represent a promising NO delivery system for the treatments of biofilm-infected chronic wounds.

Pharmaceutical feasibility and flow characteristics of polymeric non-spherical particles

Last decade has seen emergence of particle shape as a critical design parameter to overcome several long standing problems associated with particulate drug delivery- non-specific drug effects, RES uptake, poor bioavailability, achieving controlled release profiles, predictable degradation profiles, longer circulation time and zero order release kinetics to name a few. Non-spherical particles have been synthesized by techniques ranging from classical solvent evaporation to specialized techniques like film stretching and PRINT®. Non-spherical particles tend to show a difference in macrophage uptake, adhesion to target cells and distribution in vivo. This review also discusses these effects and its implications. Lastly, the impact of particle aspect ratio and other shape-governed parameters on flow properties, dispersion viscosities and other pharmaceutically relevant aspects have been briefly explained. Although there are no thumb rules yet, modern and classical literature on behavior of non-spherical particles has been reviewed and the observations have been trend-lined.