Molecular Insight into Drug-Loading Capacity of PEG-PLGA Nanoparticles for Itraconazole

Automated Analysis of Soft Matter Interfaces, Interactions, and Self-Assembly with PySoftK

Molecular dynamics simulations have become essential tools in the study of soft matter and biological macromolecules. The large amount of high-dimensional data associated with such simulations does not straightforwardly elucidate the atomistic mechanisms that underlie complex materials and molecular processes. Analysis of these simulations is complicated: the dynamics intrinsic to soft matter simulations necessitates careful application of specific, and often complex, algorithms to extract meaningful molecular scale understanding. There is an ongoing need for high-quality automated computational workflows to facilitate this analysis in a reproducible manner with minimal user input. In this work, we introduce a series of molecular simulation analysis tools for investigating interfaces, molecular interactions (including ring-ring stacking), and self-assembly. In addition, we include a number of auxiliary tools, including a useful function to unwrap molecular structures that are greater than half the length of their corresponding simulation box. These tools are contained in the PySoftK software package, making the application of these algorithms straightforward for the user. These new simulation analysis tools within PySoftK will support high-quality, reproducible analysis of soft matter and biomolecular simulations to bring about new predictive understanding in nano- and biotechnology.

Comprehensive Methodology for Evaluating the Drug Loading of Iron Oxide Nanoparticles Using Combined Magnetometry and Mössbauer Spectroscopy

A methodology for the quantitative estimation of the drug loading of iron oxide-based magnetic nanoparticles by corroborating magnetometry and Mössbauer spectroscopy investigations is reported. The proposed methodology is exemplified in the case of two series of nanoparticles, namely Fe3O4 nanoparticles covered with citric acid molecules and further functionalized with doxorubicin, and Fe3O4 nanoparticles covered with L-Cysteine molecules and further functionalized with doxorubicin. The general idea of the proposed methodology is to probe the real magnetic structure of the magnetic core via low-temperature Mössbauer spectroscopy for the correct estimation of the spontaneous magnetization of the magnetic core. It subsequently uses the ratio between the spontaneous magnetization of the covered nanoparticles and that of the magnetic core for the reliable and nondestructive evaluation of the nanoparticle loading by organic molecules. Although the methodology is exemplified in the case of magnetite-based nanoparticles, it can be successfully considered for a large class of medicine-loaded Fe-containing magnetic nanoparticles where 57Fe Mössbauer spectroscopy can be applied.

Conjugation of Antibodies and siRNA Duplexes to Polymer Nanoparticles via Maleimide-Thiol Chemistry

Polymeric nanoparticles (NPs) have shown great promise as highly modifiable platforms that can be applied across many different disease states. They are advantageous because they can encapsulate a range of hydrophobic and hydrophilic cargoes while having customizable surface properties. Depending on the desired biointerfacing capabilities, the surface of polymeric NPs can be modified with moieties, such as antibodies, peptides, nucleic acids, and more. The work presented here is intended to provide mechanistic insight into how different parameters influence the loading of antibodies, small interfering ribonucleic acids (siRNAs), or both on the surface of poly(lactic-co-glycolic acid) (PLGA) NPs via maleimide-thiol chemistry. Some of the conjugation parameters investigated include the buffer concentration, maleimide to protein ratio, and the addition of an excipient such as Tween-20. Through variation in the concentration of FZD7 antibodies added to the reaction mixture, we established tunable conjugation and found the upper limit of their loading density under the conditions tested. We also confirmed antibody conjugation through two different mechanisms: via a thiol-modified antibody or a thiol-modified poly(ethylene glycol) (PEG) linker. Conjugation of thiolated siRNA duplexes targeting β-catenin was also investigated through variations in both Tween-20 concentration and CaCl2 buffer concentration. Finally, the coconjugation of both antibodies and siRNA duplexes was explored. Overall, this work outlines a basis for tunable biomolecule loading on polymer NPs using maleimide-thiol chemistry and reveals the incredible versatility of polymer NP platforms.

Applications of Biomolecular Nanostructures for Anti-Angiogenic Theranostics

Angiogenesis is a physiological process of forming new blood vessels that has pathological importance in seemingly unrelated illnesses like cancer, diabetes, and various inflammatory diseases. Treatment targeting angiogenesis has shown promise for these types of diseases, but current anti-angiogenic agents have critical limitations in delivery and side-effects. This necessitates exploration of alternative approaches like biomolecule-based drugs. Proteins, lipids, and oligonucleotides have recently become popular in biomedicine, specifically as biocompatible components of therapeutic drugs. Their excellent bioavailability and potential bioactive and immunogenic properties make them prime candidates for drug discovery or drug delivery systems. Lipid-based liposomes have become standard vehicles for targeted nanoparticle (NP) delivery, while protein and nucleotide NPs show promise for environment-sensitive delivery as smart NPs. Their therapeutic applications have initially been hampered by short circulation times and difficulty of fabrication but recent developments in nanofabrication and NP engineering have found ways to circumvent these disadvantages, vastly improving the practicality of biomolecular NPs. In this review, we are going to briefly discuss how biomolecule-based NPs have improved anti-angiogenesis-based therapy.

Using a systematic and quantitative approach to generate new insights into drug loading of PLGA nanoparticles using nanoprecipitation

The synthesis of drug-loaded PLGA nanoparticles through nanoprecipitation in solvent/antisolvent mixtures is well reported but lacks clarity in explaining drug loading mechanisms and the prediction of efficiency of drug entrapment. Various methods using physical parameters such as log P and solid-state drug-polymer solubility aim to predict the intensity of drug-polymer interactions but lack precision. In particular, the zero-enthalpy method for drug/polymer solubility may be intrinsically inaccurate, as we demonstrate. Conventional measurement of loading capacity (LC), expressed in weight ratios, can be misleading for comparing different drugs and we stress the importance of using molar units. This research aims to provide new insights and critically evaluate the established methodologies for drug loading of PLGA nanoparticles. The study employs four model drugs with varying solubilities in solvent/antisolvent mixtures, log P values, and solid-state solubility in PLGA: ketoprofen (KPN), indomethacin (IND), sorafenib (SFN), and clofazimine (CFZ). This study highlights that drug loading efficiency is primarily influenced by the drug's solubilities within the solvent system. We emphasise that both kinetic and thermodynamic factors play a role in the behaviour of the system by considering the changes in drug solubility during mixing. The study introduces a pseudo-constant K* to characterise drug-polymer interactions, with CFZ and SFN showing the highest K* values. Interestingly, while IND and KPN have lower K* values, they achieve higher loading capacities due to their greater solubilities, indicating the key role of solubility in determining LC.

Prospect of Gum Arabic-Cocoliposome Matrix to Encapsulate Curcumin for Oral Administration

Curcumin is an antioxidant that can effectively eliminate free radicals. However, as its oral bioavailability is low, an effective delivery method is required. Phospholipid-based liposomes can encapsulate lipophilic drugs, such as curcumin, while liposome, cholesterol, and gum Arabic (GA) can enhance the internal and external stability of drug membranes. This present study used concentrations of cholesterol (Cchol) and GA (CGA), ranging from 0 to 10, 20, 30, and 40% as well as 0 to 5, 10, 15, 20, 30, and 40%, respectively, to encapsulate curcumin in a GA-cocoliposome (CCL/GA) matrix and test its efficacy in simulated intestinal fluid (SIF) and simulated gastric fluid (SGF). The absence of new characteristic peaks in the Fourier transform infrared (FTIR) spectra results indicate the presence of non-covalent interactions in the CCL/GA encapsulation. Furthermore, increasing the Cchol decreased the encapsulation efficiency (EE), loading capacity (LC), and antioxidant activity (IR) of the CCL/GA encapsulation but increased its release rate (RR). Conversely, increasing CGA increased its EE and IR but decreased its LC and RR. The two conditions applied confirmed this. Liposomal curcumin had the highest IR in SIF (84.081%) and the highest RR in SGF (0.657 ppm/day). Furthermore, liposomes loaded with 10% Cchol and 20% CGA performed best in SIF, while those loaded with 10% Cchol and 30% CGA performed best in SGF. Lastly, the CCL/GA performed better in SIF than SGF.

Self-assembled micelles loaded with itraconazole as anti-Acanthamoeba nano-formulation

Acanthamoeba castellanii are opportunistic pathogens known to cause infection of the central nervous system termed: granulomatous amoebic encephalitis, that mostly effects immunocompromised individuals, and a sight threatening keratitis, known as Acanthamoeba keratitis, which mostly affects contact lens wearers. The current treatment available is problematic, and is toxic. Herein, an amphiphilic star polymer with AB2 miktoarms [A = hydrophobic poly(ℇ-Caprolacton) and B = hydrophilic poly (ethylene glycol)] was synthesized by ring opening polymerization and CuI catalyzed azide-alkyne cycloaddition. Characterization by 1H and 13C NMR spectroscopy, size-exclusion chromatography and fluorescence spectroscopy was accomplished. The hydrophobic drug itraconazole (ITZ) was incorporated in self-assembled micellar structure of AB2 miktoarms through co-solvent evaporation. The properties of ITZ loaded (ITZ-PCL-PEG2) and blank micelles (PCL-PEG2) were investigated through zeta sizer, scanning electron microscopy and Fourier-transform infrared spectroscopy. Itraconazole alone (ITZ), polymer (DPB-PCL), empty polymeric micelles (PCL-PEG2) alone, and itraconazole loaded in polymeric micelles (ITZ-PCL-PEG2) were tested for anti-amoebic potential against Acanthamoeba, and the cytotoxicity on human cells were determined. The polymer was able to self-assemble in aqueous conditions and exhibited low value for critical micelle concentration (CMC) 0.05-0.06 µg/mL. The maximum entrapment efficiency of ITZ was 68%. Of note, ITZ, DPB, PCL-PEG2 and ITZ-PCL-PEG2 inhibited amoebae trophozoites by 37.34%, 36.30%, 35.77%, and 68.24%, respectively, as compared to controls. Moreover, ITZ-PCL-PEG2 revealed limited cytotoxicity against human keratinocyte cells. These results are indicative that ITZ-PCL-PEG2 micelle show significantly better anti-amoebic effects as compared to ITZ alone and thus should be investigated further in vivo to determine its clinical potential.

Therapeutic Peptides Are Preferentially Solubilized in Specific Microenvironments within PEG-PLGA Polymer Nanoparticles

Polymeric nanoparticles are a highly promising drug delivery formulation. However, a lack of understanding of the molecular mechanisms that underlie their drug solubilization and controlled release capabilities has hindered the efficient clinical translation of such technologies. Polyethylene glycol-poly(lactic-co-glycolic) acid (PEG-PLGA) nanoparticles have been widely studied as cancer drug delivery vehicles. In this letter, we use unbiased coarse-grained molecular dynamics simulations to model the self-assembly of a PEG-PLGA nanoparticle and its solubulization of the anticancer peptide, EEK, with good agreement with previously reported experimental structural data. We applied unsupervised machine learning techniques to quantify the conformations that polymers adopt at various locations within the nanoparticle. We find that the local microenvironments formed by the various polymer conformations promote preferential EEK solubilization within specific regions of the NP. This demonstrates that these microenvironments are key in controlling drug storage locations within nanoparticles, supporting the rational design of nanoparticles for therapeutic applications.

Antibody-Conjugated Polymersomes with Encapsulated Indocyanine Green J-Aggregates and High Near-Infrared Absorption for Molecular Photoacoustic Cancer Imaging

Imaging plays a critical role in all stages of cancer care from early detection to diagnosis, prognosis, and therapy monitoring. Recently, photoacoustic imaging (PAI) has started to emerge into the clinical realm due to its high sensitivity and ability to penetrate tissues up to several centimeters deep. Herein, we encapsulated indocyanine green J (ICGJ) aggregate, one of the only FDA-approved organic exogenous contrast agents that absorbs in the near-infrared range, at high loadings up to ∼40% w/w within biodegradable polymersomes (ICGJ-Ps) composed of poly(lactide-co-glycolide-b-polyethylene glycol) (PLGA-b-PEG). The small Ps hydrodynamic diameter of 80 nm is advantageous for in vivo applications, while directional conjugation with epidermal growth factor receptor (EGFR) targeting cetuximab antibodies renders molecular specificity. Even when exposed to serum, the ∼11 nm-thick membrane of the Ps prevents dissociation of the encapsulated ICGJ for at least 48 h with a high ratio of ICGJ to monomeric ICG absorbances (i.e., I895/I780 ratio) of approximately 5.0 that enables generation of a strong NIR photoacoustic (PA) signal. The PA signal of polymersome-labeled breast cancer cells is proportional to the level of cellular EGFR expression, indicating the feasibility of molecular PAI with antibody-conjugated ICGJ-Ps. Furthermore, the labeled cells were successfully detected with PAI in highly turbid tissue-mimicking phantoms up to a depth of 5 mm with the PA signal proportional to the amount of cells. These data show the potential of molecular PAI with ICGJ-Ps for clinical applications such as tumor margin detection, evaluation of lymph nodes for the presence of micrometastasis, and laparoscopic imaging procedures.

Degradable Polymeric Bio(nano)materials and Their Biomedical Applications: A Comprehensive Overview and Recent Updates

Degradable polymers (both biomacromolecules and several synthetic polymers) for biomedical applications have been promising very much in the recent past due to their low cost, biocompatibility, flexibility, and minimal side effects. Here, we present an overview with updated information on natural and synthetic degradable polymers where a brief account on different polysaccharides, proteins, and synthetic polymers viz. polyesters/polyamino acids/polyanhydrides/polyphosphazenes/polyurethanes relevant to biomedical applications has been provided. The various approaches for the transformation of these polymers by physical/chemical means viz. cross-linking, as polyblends, nanocomposites/hybrid composites, interpenetrating complexes, interpolymer/polyion complexes, functionalization, polymer conjugates, and block and graft copolymers, are described. The degradation mechanism, drug loading profiles, and toxicological aspects of polymeric nanoparticles formed are also defined. Biomedical applications of these degradable polymer-based biomaterials in and as wound dressing/healing, biosensors, drug delivery systems, tissue engineering, and regenerative medicine, etc., are highlighted. In addition, the use of such nano systems to solve current drug delivery problems is briefly reviewed.

Hydrophobic ion pairing and microfluidic nanoprecipitation enable efficient nanoformulation of a small molecule indolamine 2, 3-dioxygenase inhibitor immunotherapeutic

Blockade of programmed cell death-1 (PD-1) is a transformative immunotherapy. However, only a fraction of patients benefit, and there is a critical need for broad-spectrum checkpoint inhibition approaches that both enhance the recruitment of cytotoxic immune cells in cold tumors and target resistance pathways. Indoleamine 2, 3-dioxygenase (IDO) small molecule inhibitors are promising but suboptimal tumor bioavailability and dose-limiting toxicity have limited therapeutic benefits in clinical trials. This study reports on a nanoformulation of the IDO inhibitor navoximod within polymeric nanoparticles prepared using a high-throughput microfluidic mixing device. Hydrophobic ion pairing addresses the challenging physicochemical properties of navoximod, yielding remarkably high loading (>10%). The nanoformulation efficiently inhibits IDO and, in synergy with PD-1 antibodies improves the anti-cancer cytotoxicity of T-cells, in vitro and in vivo. This study provides new insight into the IDO and PD-1 inhibitors synergy and validates hydrophobic ion pairing as a simple and clinically scalable formulation approach.

Weibull β value for the discernment of drug release mechanism of PLGA particles

Mathematical models are used to characterize and optimize drug release in drug delivery systems (DDS). One of the most widely used DDS is the poly(lactic-co-glycolic acid) (PLGA)-based polymeric matrix owing to its biodegradability, biocompatibility, and easy manipulation of its properties through the manipulation of synthesis processes. Over the years, the Korsmeyer-Peppas model has been the most widely used model for characterizing the release profiles of PLGA DDS. However, owing to the limitations of the Korsmeyer-Peppas model, the Weibull model has emerged as an alternative for the characterization of the release profiles of PLGA polymeric matrices. The purpose of this study was to establish a correlation between the n and β parameters of the Korsmeyer-Peppas and Weibull models and to use the Weibull model to discern the drug release mechanism. A total of 451 datasets describing the overtime drug release of PLGA-based formulations from 173 scientific articles were fitted to both models. The Korsmeyer-Peppas model had a mean Akaike Information Criteria (AIC) value of 54.52 and an n value of 0.42, while the Weibull model had a mean AIC of 51.99 and a β value of 0.55, and by using reduced major axis regression values, a high correlation was found between the n and β values. These results demonstrate the ability of the Weibull model to characterize the release profiles of PLGA-based matrices and the usefulness of the β parameter for determining the drug release mechanism.

Design of Chitosan-Coated, Quercetin-Loaded PLGA Nanoparticles for Enhanced PSMA-Specific Activity on LnCap Prostate Cancer Cells

Nanoparticles are designed to entrap drugs at a high concentration, escape clearance by the immune system, be selectively taken up by cancer cells, and release bioactives in a rate-modulated manner. In this study, quercetin-loaded PLGA nanoparticles were prepared and optimized to determine whether coating with chitosan would increase the cellular uptake of the nanoparticles and if the targeting ability of folic acid as a ligand can provide selective toxicity and enhanced uptake in model LnCap prostate cancer cells, which express high levels of the receptor prostate-specific membrane antigen (PSMA), compared to PC-3 cells, that have relatively low PSMA expression. A design of experiments approach was used to optimize the PLGA nanoparticles to have the maximum quercetin loading, optimal cationic charge, and folic acid coating. We examined the in vitro release of quercetin and comparative cytotoxicity and cellular uptake of the optimized PLGA nanoparticles and revealed that the targeted nano-system provided sustained, pH-dependent quercetin release, and higher cytotoxicity and cellular uptake, compared to the non-targeted nano-system on LnCap cells. There was no significant difference in the cytotoxicity or cellular uptake between the targeted and non-targeted nano-systems on PC-3 cells (featured by low levels of PSMA), pointing to a PSMA-specific mechanism of action of the targeted nano-system. The findings suggest that the nano-system can be used as an efficient nanocarrier for the targeted delivery and release of quercetin (and other similar chemotherapeutics) against prostate cancer cells.

Miscibility of Phosphatidylcholines in Bilayers: Effect of Acyl Chain Unsaturation

The miscibility of phospholipids in a hydrated bilayer is an issue of fundamental importance for understanding the organization of biological membranes. Despite research on lipid miscibility, its molecular basis remains poorly understood. In this study, all-atom MD simulations complemented by Langmuir monolayer and DSC experiments have been performed to investigate the molecular organization and properties of lipid bilayers composed of phosphatidylcholines with saturated (palmitoyl, DPPC) and unsaturated (oleoyl, DOPC) acyl chains. The experimental results showed that the DOPC/DPPC bilayers are systems exhibiting a very limited miscibility (strongly positive values of excess free energy of mixing) at temperatures below the DPPC phase transition. The excess free energy of mixing is divided into an entropic component, related to the ordering of the acyl chains, and an enthalpic component, resulting from the mainly electrostatic interactions between the headgroups of lipids. MD simulations showed that the electrostatic interactions for lipid like-pairs are much stronger than that for mixed pairs and temperature has only a slight influence on these interactions. On the contrary, the entropic component increases strongly with increasing temperature, due to the freeing of rotation of acyl chains. Therefore, the miscibility of phospholipids with different saturations of acyl chains is an entropy-driven process.

Significance of native PLGA nanoparticles in the treatment of Alzheimer's disease pathology

Alzheimer's disease (AD) is believed to be triggered by increased levels/aggregation of β-amyloid (Aβ) peptides. At present, there is no effective disease-modifying treatment for AD. Here, we evaluated the therapeutic potential of FDA-approved native poly(d,l-lactide-co-glycolide) (PLGA) nanoparticles on Aβ aggregation and in cellular/animal models of AD. Our results showed that native PLGA can not only suppress the spontaneous aggregation but can also trigger disassembly of preformed Aβ aggregates. Spectroscopic studies, molecular dynamics simulations and biochemical analyses revealed that PLGA, by interacting with the hydrophobic domain of Aβ_1-42, prevents a conformational shift towards the β-sheet structure, thus precluding the formation and/or triggering disassembly of Aβ aggregates. PLGA-treated Aβ samples can enhance neuronal viability by reducing phosphorylation of tau protein and its associated signaling mechanisms. Administration of PLGA can interact with Aβ aggregates and attenuate memory deficits as well as Aβ levels/deposits in the 5xFAD mouse model of AD. PLGA can also protect iPSC-derived neurons from AD patients against Aβ toxicity by decreasing tau phosphorylation. These findings provide unambiguous evidence that native PLGA, by targeting different facets of the Aβ axis, can have beneficial effects in mouse neurons/animal models as well as on iPSC-derived AD neurons - thus signifying its unique therapeutic potential in the treatment of AD pathology.

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PLGA nanoparticles by interacting with hydrophobic domain inhibit Aβ aggregation.

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PLGA-mediated inhibition of Aβ aggregation can increase viability of mouse neurons.

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PLGA administration can attenuate cognitive deficits/pathology in 5xFAD AD mouse model.

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PLGA can protect iPSC-derived neurons from AD patients against Aβ toxicity.

A Coarse-Grained Molecular Dynamics Description of Docetaxel-Conjugate Release from PLGA Matrices

Despite the extensive use of poly-lactic-glycolic-acid (PLGA) in biomedical applications, computational research on the mesoscopic characterization of PLGA-based delivery systems is limited. In this study, a computational model for PLGA is proposed, developed, and validated for the reproducibility of transport properties that can influence drug release, the rate of which remains difficult to control. For computational efficiency, coarse-grained (CG) models of the molecular components under consideration were built using the MARTINI force field version 2.2. The translocation free energy barrier ΔG_t^* across the PLGA matrix in the aqueous phase of docetaxel and derivatives of varying sizes and solubilities was predicted via molecular dynamics (MD) simulations and compared with experimental release data. The thermodynamic quantity ΔG_t^* anticipates and can help explain the release kinetics of hydrophobic compounds from the PLGA matrix, albeit within the limit of a drug concentration below a critical aggregation concentration. The proposed computational framework would allow one to predict the pharmacological behavior of polymeric implants loaded with a variety of payloads under different conditions, limiting the experimental workload and associated costs.

In Vitro Evaluation of Curcumin Encapsulation in Gum Arabic Dispersions under Different Environments

Biopolymers, especially polysaccharides (e.g., gum Arabic), are widely applied as drug carriers in drug delivery systems due to their advantages. Curcumin, with high antioxidant ability but limited solubility and bioavailability in the body, can be encapsulated in gum Arabic to improve its solubility and bioavailability. When curcumin is encapsulated in gum Arabic, it is essential to understand how it works in various conditions. As a result, in Simulated Intestinal Fluid and Simulated Gastric Fluid conditions, we investigated the potential of gum Arabic as the drug carrier of curcumin. This study was conducted by varying the gum Arabic concentrations, i.e., 5, 10, 15, 20, 30, and 40%, to encapsulate 0.1 mg/mL of curcumin. Under both conditions, the greater the gum Arabic concentration, the greater the encapsulation efficiency and antioxidant activity of curcumin, but the worse the gum Arabic loading capacity. To achieve excellent encapsulation efficiency, loading capacity, and antioxidant activity, the data advises that 10% is the best feasible gum Arabic concentration. Regarding the antioxidant activity of curcumin, the findings imply that a high concentration of gum Arabic was effective, and the Simulated Intestinal Fluid brought an excellent surrounding compared to the Simulated Gastric Fluid solution. Moreover, the gum Arabic releases curcumin faster in the Simulated Gastric Fluid condition.

Biomolecular engineering of drugs loading in Riboflavin-targeted polymeric devices: simulation and experimental

The synthesis of polymeric nanoparticles (NPs) with efficient drug loading content and targeting moieties is an attractive field and remains a challenge in drug delivery systems. Atomistic investigations can provide an in-depth understanding of delivery devices and reduce the number of expensive experiments. In this paper, we studied the self-assembly of poly (lactic-co-glycolic acid)-b-poly (ethylene glycol) with different molecular weights and surface compositions. The innovation of this molecular study is the loading of an antitumor drug (docetaxel) on a targeting ligand (riboflavin). According to this work, a novel, biocompatible and targeted system for cancer treatment has been developed. The obtained results revealed a correlation between polymer molecular weight and the stability of particles. In this line, samples including 20 and 10 w/w% moiety NPs formed from polymers with 3 and 4.5 kDa backbone sizes, respectively, are the stable models with the highest drug loading and entrapment efficiencies. Next, we evaluated NP morphology and found that NPs have a core/shell structure consisting of a hydrophobic core with a shell of poly (ethylene glycol) and riboflavin. Interestingly, morphology assessments confirmed that the targeting moiety located on the surface can improve drug delivery to receptors and cancerous cells. The developed models provided significant insight into the structure and morphology of NPs before the synthesis and further analysis of NPs in biological environments. However, in the best cases of this system, Dynamic Light Scattering (DLS) tests were also taken and the results were consistent with the results obtained from All Atom and Coarse Grained simulations.

In vivo Evaluation of Non-viral NICD Plasmid-Loaded PLGA Nanoparticles in Developing Zebrafish to Improve Cardiac Functions

In the era of the advanced nanomaterials, use of nanoparticles has been highlighted in biomedical research. However, the demonstration of DNA plasmid delivery with nanoparticles for in vivo gene delivery experiments must be carefully tested due to many possible issues, including toxicity. The purpose of the current study was to deliver a Notch Intracellular Domain (NICD)-encoded plasmid via poly(lactic-co-glycolic acid) (PLGA) nanoparticles and to investigate the toxic environmental side effects for an in vivo experiment. In addition, we demonstrated the target delivery to the endothelium, including the endocardial layer, which is challenging to manipulate gene expression for cardiac functions due to the beating heart and rapid blood pumping. For this study, we used a zebrafish animal model and exposed it to nanoparticles at varying concentrations to observe for specific malformations over time for toxic effects of PLGA nanoparticles as a delivery vehicle. Our nanoparticles caused significantly less malformations than the positive control, ZnO nanoparticles. Additionally, the NICD plasmid was successfully delivered by PLGA nanoparticles and significantly increased Notch signaling related genes. Furthermore, our image based deep-learning analysis approach evaluated that the antibody conjugated nanoparticles were successfully bound to the endocardium to overexpress Notch related genes and improve cardiac function such as ejection fraction, fractional shortening, and cardiac output. This research demonstrates that PLGA nanoparticle-mediated target delivery to upregulate Notch related genes which can be a potential therapeutic approach with minimum toxic effects.

Engineering macromolecular nanocarriers for local delivery of gaseous signaling molecules

In addition to being notorious air pollutants, nitric oxide (NO), carbon monoxide (CO), and hydrogen sulfide (H₂S) have also been known as endogenous gaseous signaling molecules (GSMs). These GSMs play critical roles in maintaining the homeostasis of living organisms. Importantly, the occurrence and development of many diseases such as inflammation and cancer are highly associated with the concentration changes of GSMs. As such, GSMs could also be used as new therapeutic agents, showing great potential in the treatment of many formidable diseases. Although clinically it is possible to directly inhale GSMs, the precise control of the dose and concentration for local delivery of GSMs remains a substantial challenge. The development of gaseous signaling molecule-releasing molecules provides a great tool for the safe and convenient delivery of GSMs. In this review article, we primarily focus on the recent development of macromolecular nanocarriers for the local delivery of various GSMs. Learning from the chemistry of small molecule-based donors, the integration of these gaseous signaling molecule-releasing molecules into polymeric matrices through physical encapsulation, post-modification, or direct polymerization approach renders it possible to fabricate numerous macromolecular nanocarriers with optimized pharmacokinetics and pharmacodynamics, revealing improved therapeutic performance than the small molecule analogs. The development of GSMs represents a new means for many disease treatments with unique therapeutic outcomes.

Formulation design and mechanism study of hydrogel based on computational pharmaceutics theories

Formulation design and mechanism study of the drug delivery system (DDS) is an important but difficult subject in pharmaceutical research. The study of formulation factors is the most time- and labor-consuming work of formulation design. In this paper, a multiscale computational pharmaceutics strategy was developed to guide the systematic study of formulation factors of a typical polymer-based DDS, hydrogel, and further to guide the formulation design. According to the strategy, the combination of solubility parameter (δ) and diffusion coefficient (D) calculated by the AA-MD simulation was suggested as the general evaluation method for the matrix screening of the hydrogels at the pre-formulation stage. At the formulation design stage, the CG-MD simulation method was suggested to predict the morphology and drug-releasing behavior of the hydrogels under different formulation factors. The influence mechanism can be explained by the combination of multiple parameters, such as the microstructure diagram, the radius of gyration (Rg), the radial distribution function (RDF), and the free diffusion volume (V_diffusion). The simulation results are in good agreement with the in vitro release experiment, indicating that the strategy has good applicability.

Notch Intracellular Domain Plasmid Delivery via Poly(Lactic-Co-Glycolic Acid) Nanoparticles to Upregulate Notch Pathway Molecules

Notch signaling is a highly conserved signaling system that is required for embryonic development and regeneration of organs. When the signal is lost, maldevelopment occurs and leads to a lethal state. Delivering exogenous genetic materials encoding Notch into cells can reestablish downstream signaling and rescue cellular functions. In this study, we utilized the negatively charged and FDA approved polymer poly(lactic-co-glycolic acid) to encapsulate Notch Intracellular Domain-containing plasmid in nanoparticles. We show that primary human umbilical vein endothelial cells (HUVECs) readily uptake the nanoparticles with and without specific antibody targets. We demonstrated that our nanoparticles are non-toxic, stable over time, and compatible with blood. We further demonstrated that HUVECs could be successfully transfected with these nanoparticles in static and dynamic environments. Lastly, we elucidated that these nanoparticles could upregulate the downstream genes of Notch signaling, indicating that the payload was viable and successfully altered the genetic downstream effects.

Development and Optimization of Itraconazole-Loaded Solid Lipid Nanoparticles for Topical Administration Using High Shear Homogenization Process by Design of Experiments: In Vitro, Ex Vivo and In Vivo Evaluation

The aim of present study was to develop topical itraconazole (ITZ)-loaded solid lipid nanoparticles for treatment of superficial fungal infections. Formulations were prepared using high shear homogenization process, and optimized by employing a two-step design of experiments (DoE) approach. It comprised a Taguchi experimental design for screening of 'vital few' factors, and a central composite experimental design for optimization. Overlay of the response surface maps for percent drug entrapment (PDE), particle size, ITZ skin retention and permeation was performed to obtain the optimized ITZ-loaded SLNs (OPT-SLNs) suspension. The optimized ITZ-loaded SLNs (OPT-SLNs) showed mean particle size of (262.92 ± 8.56 nm) and zeta potential value of 22.36 mV. Excellent drug entrapment (94.21 ± 3.35%) and skin retention of ITZ (43.03 ± 1.86 μg/cm²) was achieved by OPT-SLNs. The hydrogel formulation of OPT-SLNs exhibited good gel consistency and spreadability characteristics. Pharmacodynamic and skin sensitivity studies in standardized rodent models revealed that OPT-SLNs hydrogel was more efficacious than conventional oral and topical antifungal therapies, and also safe for topical administration. Furthermore, the histoptahological evaluation depicted complete recovery of infected rats after 14-day treatment regimen of OPT-SLNs hydrogel. The developed formulation was found to have tremendous potential to enhance ITZ activity through topical administration approach.

Influence of lactide vs glycolide composition of poly (lactic-co-glycolic acid) polymers on encapsulation of hydrophobic molecules: molecular dynamics and formulation studies

The work demonstrates the preparation of PLGA (PLGA 50:50, PLGA 75:25) nanoparticles, to encapsulate a hydrophobic molecule (coumarin-6), using the microreactor-based continuous process. The formulations were characterized using dynamic light scattering and transmission electron microscopy to determine their size, homogeneity, zeta potential, and surface morphology. The resulting nanoparticles were safe to the CHO cells (≈80% cell survival), at the concentration of ≤600 µg/mL and were successfully taken up by the cells, as demonstrated using confocal microscopy. Moreover, imaging flow cytometry confirmed that the nanoparticles were internalized in 73.96% of the cells. Furthermore, molecular dynamics simulation and docking studies were carried out to explore the effect of polymer chain length of PLGA and lactide vs glycolide (LA:GA) ratio on their compatibility with the coumarin-6 molecules and to study the coiling and flexibility of PLGA in the presence of coumarin-6 molecules. Flory-Huggins interaction parameter (χ) was calculated for polymer chains of varying lengths and LA:GA ratio, with respect to coumarin-6. χ parameter increased with increase in polymer chain length, which indicated superior interaction of coumarin-6 with the smaller chains. Amongst all the polymeric systems, PLGA55 exhibited the strongest interaction with coumarin-6, for all the chain lengths, possibly because of their homogeneous spatial arrangements and superior binding energy. PLGA27 showed better compatibility compared to PLGA72 and PGA, whereas PLA-based polymers exhibited the least compatibility. Analysis of the radius of gyration of the polymer chains in the polymer-coumarin-6 complexes, at the end of molecular dynamics run, exhibited that the polymer chains displayed varying coiling behavior and flexibility, depending upon the relative concentrations of the polymer and coumarin-6. Factors like intra-chain interactions, spatial arrangement, inter-chain binding energies, and polymer-coumarin-6 compatibility also influenced the coiling and flexibility of polymer chains.

Experimental and Computational Study on the Microfluidic Control of Micellar Nanocarrier Properties

Microfluidic-based synthesis is a powerful technique to prepare well-defined homogenous nanoparticles (NPs). However, the mechanisms defining NP properties, especially size evolution in a microchannel, are not fully understood. Herein, microfluidic and bulk syntheses of riboflavin (RF)-targeted poly(lactic-co-glycolic acid)-poly(ethylene glycol) (PLGA-PEG-RF) micelles were evaluated experimentally and computationally. Using molecular dynamics (MD), a conventional "random" model for bulk self-assembly of PLGA-PEG-RF was simulated and a conceptual "interface" mechanism was proposed for the microfluidic self-assembly at an atomic scale. The simulation results were in agreement with the observed experimental outcomes. NPs produced by microfluidics were smaller than those prepared by the bulk method. The computational approach suggested that the size-determining factor in microfluidics is the boundary of solvents in the entrance region of the microchannel, explaining the size difference between the two experimental methods. Therefore, this computational approach can be a powerful tool to gain a deeper understanding and optimize NP synthesis.

Self-Assembled Chromogenic Polymeric Nanoparticle-Laden Nanocarrier as a Signal Carrier for Derivative Binary Responsive Virus Detection

In the current biosensor, the signal generation is limited to single virus detection in the reaction chamber. An adaptive strategy is required to enable the recognition of multiple viruses for diagnostics and surveillance. In this work, a nanocarrier is deployed to bring specific signal amplification into the biosensor, depending on the target viruses. The nanocarrier is designed using pH-sensitive polymeric nanoparticle-laden nanocarriers (PNLNs) prepared by sequential nanoprecipitation. The nanoprecipitation of two chromogens, phenolphthalein (PP) and thymolphthalein (TP), is investigated in three different solvent systems in which PNLNs demonstrate a high loading of the chromogen up to 59.75% in dimethylformamide (DMF)/dimethyl sulfoxide (DMSO)/ethanol attributing to the coprecipitation degree of the chromogens and the polymer. The PP-encapsulated PNLNs (PP@PNLNs) and TP-encapsulated PNLNs (TP@PNLNs) are conjugated to antibodies specific to target viruses, influenza virus A subtype H1N1 (IV/A/H1N1) and H3N2 (IV/A/H3N2), respectively. After the addition of anti-IV/A antibody-conjugated magnetic nanoparticles (MNPs) and magnetic separation, the enriched PNLNs/virus/MNPs sandwich structure is treated in an alkaline solution. It demonstrates a synergy reaction in which the degradation of the polymeric boundary and the pH-induced colorimetric development of the chromogen occurred. The derivative binary biosensor shows feasible detection on IV/A with excellent specificities of PP@PNLNs on IV/A/H1N1 and TP@PNLNs on IV/A/H3N2 with LODs of 27.56 and 28.38 fg mL^-1, respectively. It intrigues the distinguished analytical signal in human serum with a variance coefficient of 25.8% and a recovery of 93.6-110.6% for one-step subtype influenza virus detection.

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.

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.

Encapsulation of Curcumin in Polystyrene-Based Nanoparticles-Drug Loading Capacity and Cytotoxicity

Nanoparticles made of amphiphilic block copolymers are commonly used in the preparation of nano-sized drug delivery systems. Poly(styrene)-block -poly(acrylic acid) (PS-PAA) copolymers have been proposed for drug delivery purposes; however, the drug loading capacity and cytotoxicity of PS-PAA nanoparticles are still not fully recognized. Herein, we investigated the accumulation of a model hydrophobic drug, curcumin, and its spatial distribution inside the PS-PAA nanoparticles. Experimental methods and atomistic molecular dynamics simulations were used to understand the molecular structure of the PS core and how curcumin molecules interact and organize within the PS matrix. The hydrophobic core of the PS-PAA nanoparticles consists of adhering individually coiled polymeric chains and is compact enough to prevent post-incorporation of curcumin. However, the drug has a good affinity for the PS matrix and can be efficiently enclosed in the PS-PAA nanoparticles at the formation stage. At low concentrations, curcumin is evenly distributed in the PS core, while its aggregates were observed above ca. 2 wt %. The nanoparticles were found to have relatively low cytotoxicity to human skin fibroblasts, and the presence of curcumin further increased their biocompatibility. Our work provides a detailed description of the interactions between a hydrophobic drug and PS-PAA nanoparticles and information on the biocompatibility of these anionic nanostructures which may be relevant to the development of amphiphilic copolymer-based drug delivery systems.

Enhancing Cancer Immunotherapy Treatment Goals by Using Nanoparticle Delivery System

Recently, there has been an incredible increase in research about the abnormal growth of cells (neoplasm), focusing on the management, treatment and preventing reoccurrence. It has been understood that the natural defense system, composed of a variety of immune defensive cells, does not just limit its function in eliminating neoplastic cells, but also controls the growth and spread of tumor cells of different kinds to other parts of the body. Cancer immunotherapy, is a cancer treatment plan that educates the body’s defensive system to forestall, control, and eliminate tumor cells. The effectiveness of immunotherapy is achieved, to its highest efficacy, by the use of nanoparticles (NPs) for precise and timely delivery of immunotherapies to specific targeted neoplasms, with less or no harm to the healthy cells. Immunotherapies have been affirmed in clinical trials as a cancer regimen for various types of cancers, the side effects resulting from imprecise and non-targeted conveyance is well managed with the use of nanoparticles. Nonetheless, we will concentrate on enhancing cancer immunotherapy approaches by the use of nanoparticles for the productivity of antitumor immunity. Nanoparticles will be presented and utilized as an objective immunotherapy delivery system for high exactness and are thus a promising methodology for cancer treatment.

Not only in silico drug discovery: Molecular modeling towards in silico drug delivery formulations

The use of methods at molecular scale for the discovery of new potential active ligands, as well as previously unknown binding sites for target proteins, is now an established reality. Literature offers many successful stories of active compounds developed starting from insights obtained in silico and approved by Food and Drug Administration (FDA). One of the most famous examples is raltegravir, a HIV integrase inhibitor, which was developed after the discovery of a previously unknown transient binding area thanks to molecular dynamics simulations. Molecular simulations have the potential to also improve the design and engineering of drug delivery devices, which are still largely based on fundamental conservation equations. Although they can highlight the dominant release mechanism and quantitatively link the release rate to design parameters (size, drug loading, et cetera), their spatial resolution does not allow to fully capture how phenomena at molecular scale influence system behavior. In this scenario, the "computational microscope" offered by simulations at atomic scale can shed light on the impact of molecular interactions on crucial parameters such as release rate and the response of the drug delivery device to external stimuli, providing insights that are difficult or impossible to obtain experimentally. Moreover, the new paradigm brought by nanomedicine further underlined the importance of such computational microscope to study the interactions between nanoparticles and biological components with an unprecedented level of detail. Such knowledge is a fundamental pillar to perform device engineering and to achieve efficient and safe formulations. After a brief theoretical background, this review aims at discussing the potential of molecular simulations for the rational design of drug delivery systems.

ROS-Sensitive Nanoparticles Co-delivering Dexamethasone and CDMP-1 for the Treatment of Osteoarthritis Through Chondrogenic Differentiation Induction and Inflammation Inhibition

Objective: Osteoarthritis (OA) is a common subtype of arthritis. To date, treatment of OA focuses primarily on alleviating pain and improving joint function. The lack of a vascular system within synovial joints and the rapid removal of agents due to synovial exchange hinder continuous delivery of OA drugs. However, these obstacles are being addressed by promising nanoscale drugs.

Methods: We synthesize and assemble a hydrogen peroxide [H₂O₂, belongs to the category of active oxygen species (ROS)]-sensitive nanomicelle, which is loaded with the anti-inflammation drug dexamethasone and chondrogenic differentiation factor cartilage-derivedmor-phogeneticprotein-1. The micelle can induce bone marrow mesenchymal stem cells to repair cartilage while inhibiting joint inflammation.

Results: The prepared nanoparticles were of uniform size and displayed an obvious core-shell structure. Under H₂O₂ stimulation, the shell layer could be removed gradually. The drug-loaded micelle effectively inhibited proliferation of activated macrophages, induced macrophage apoptosis with an anti-inflammatory effect, and caused the BMSCs to differentiate into chondrocytes.

Conclusion: This work provides an experimental and theoretical basis for further development of a drug-loaded micelle in the healing of osteoarthritis.

Effect of ligand conjugation site on the micellization of Bio-Targeted PLGA-Based nanohybrids: A computational biology approach

In this study, the effect of ligand binding position on the polymeric nanoparticles (NPs) is based on poly(lactic-co-glycolic acid) (PLGA) with two different polymer chain length at the atomistic level was presented. We explored the conjugation of riboflavin (RF) ligand from the end of the ribityl chain (N-10) to the polymer strands as well as from the amine group on the isoalloxazine head (N-3). The energy interactions for all samples revealed that the NPs containing ligands from N-10 positions have higher total attraction energies and lower stability in comparison with their peers conjugated from N-3. As NPs containing RF conjugated from N-3 exhibit the lower energy level with 20% and 10% of RF-containing composition for lower and higher. The introduction of RF from the N-10 position in any composition has increased the energy level of nanocarriers. The results of Gibb's free energy confirm the interatomic interaction energies trend where the lowest Gibbs free energy level for N-3 NPs occurs at 20 and 10% of RF-containing polymer content for PLGA10- and PLGA11- based NPs. Furthermore, with N-10 samples based on both polymers, non-targeted models form the stablest particles in each category. These findings are further confirmed with molecular docking analysis which revealed affinity energy of RF toward polymer chain from N-3 and N-10 are -981.57 kJ/mole and -298.23 kJ/mole, respectively. This in-silico study paves the new way for molecular engineering of the bio-responsive PLGA-PEG-RF micelles and can be used to nanoscale tunning of smart carriers used in cancer treatment.Communicated by Ramaswamy H. Sarma.

Drug-loading capacity of polylactide-based micro- and nanoparticles - Experimental and molecular modeling study

Micro- and nanostructures prepared from biodegradable homopolymers and amphiphilic block copolymers (AmBCs) have found application as drug-delivery systems (DDSs). The ability to accumulate a drug is a very important parameter characterizing a given DDS. This work focuses on the impact of DDS size, the packing of polymer chains in the DDS, and drug - polymer matrix compatibility on the hydrophobic drug - loading capacity (DLC) of nano/microcarriers prepared from a biodegradable polymer or its copolymer. Using experimental measurements in combination with atomistic molecular dynamics simulations, an analysis of curcumin encapsulation in microspheres (MSs) from polylactide (PLA) homopolymer and nanoparticles (NPs) from PLA-block-poly(2-methacryloyloxyethylphosphorylcholine) AmBC was performed. The results show that curcumin has good affinity for the PLA matrix due to its hydrophobic nature. However, the DLC value is limited by the fact that curcumin only accumulates in the peripheral part of these structures. Such uneven drug distribution in the PLA matrix results from the non-homogeneous density of MSs (non-uniform packing of the polymer chains in the coil). The results also indicate that the MSs can retain a greater amount of hydrophobic drug compared to the NPs, which is associated with the formation of drug aggregates inside the PLA microparticles.

Polymeric micelles for the delivery of poorly soluble drugs: From nanoformulation to clinical approval

Over the last three decades, polymeric micelles have emerged as a highly promising drug delivery platform for therapeutic compounds. Particularly, poorly soluble small molecules with high potency and significant toxicity were encapsulated in polymeric micelles. Polymeric micelles have shown improved pharmacokinetic profiles in preclinical animal models and enhanced efficacy with a superior safety profile for therapeutic drugs. Several polymeric micelle formulations have reached the clinical stage and are either in clinical trials or are approved for human use. This furthers interest in this field and underscores the need for additional learning of how to best design and apply these micellar carriers to improve the clinical outcomes of many drugs. In this review, we provide detailed information on polymeric micelles for the solubilization of poorly soluble small molecules in topics such as the design of block copolymers, experimental and theoretical analysis of drug encapsulation in polymeric micelles, pharmacokinetics of drugs in polymeric micelles, regulatory approval pathways of nanomedicines, and current outcomes from micelle formulations in clinical trials. We aim to describe the latest information on advanced analytical approaches for elucidating molecular interactions within the core of polymeric micelles for effective solubilization as well as for analyzing nanomedicine's pharmacokinetic profiles. Taking into account the considerations described within, academic and industrial researchers can continue to elucidate novel interactions in polymeric micelles and capitalize on their potential as drug delivery vehicles to help improve therapeutic outcomes in systemic delivery.

Comparative Nanofabrication of PLGA-Chitosan-PEG Systems Employing Microfluidics and Emulsification Solvent Evaporation Techniques

Poor circulation stability and inadequate cell membrane penetration are significant impediments in the implementation of nanocarriers as delivery systems for therapeutic agents with low bioavailability. This research discusses the fabrication of a biocompatible poly(lactide-co-glycolide) (PLGA) based nanocarrier with cationic and hydrophilic surface properties provided by natural polymer chitosan and coating polymer polyethylene glycol (PEG) for the entrapment of the hydrophobic drug disulfiram. The traditional emulsification solvent evaporation method was compared to a microfluidics-based method of fabrication, with the optimisation of the parameters for each method, and the PEGylation densities on the experimental nanoparticle formulations were varied. The size and surface properties of the intermediates and products were characterised and compared by dynamic light scattering, scanning electron microscopy and X-ray diffraction, while the thermal properties were investigated using thermogravimetric analysis and differential scanning calorimetry. Results showed optimal particle properties with an intermediate PEG density and a positive surface charge for greater biocompatibility, with nanoparticle surface characteristics shielding physical interaction of the entrapped drug with the exterior. The formulations prepared using the microfluidic method displayed superior surface charge, entrapment and drug release properties. The final system shows potential as a component of a biocompatible nanocarrier for poorly soluble drugs.

Burgeoning Polymer Nano Blends for Improved Controlled Drug Release: A Review

With continual rapid developments in the biomedical field and understanding of the important mechanisms and pharmacokinetics of biological molecules, controlled drug delivery systems (CDDSs) have been at the forefront over conventional drug delivery systems. Over the past several years, scientists have placed boundless energy and time into exploiting a wide variety of excipients, particularly diverse polymers, both natural and synthetic. More recently, the development of nano polymer blends has achieved noteworthy attention due to their amazing properties, such as biocompatibility, biodegradability and more importantly, their pivotal role in controlled and sustained drug release in vitro and in vivo. These compounds come with a number of effective benefits for improving problems of targeted or controlled drug and gene delivery systems; thus, they have been extensively used in medical and pharmaceutical applications. Additionally, they are quite attractive for wound dressings, textiles, tissue engineering, and biomedical prostheses. In this sense, some important and workable natural polymers (namely, chitosan (CS), starch and cellulose) and some applicable synthetic ones (such as poly-lactic-co-glycolic acid (PLGA), poly(lactic acid) (PLA) and poly-glycolic acid (PGA)) have played an indispensable role over the last two decades for their therapeutic effects owing to their appealing and renewable biological properties. According to our data, this is the first review article highlighting CDDSs composed of diverse natural and synthetic nano biopolymers, blended for biological purposes, mostly over the past five years; other reviews have just briefly mentioned the use of such blended polymers. We, additionally, try to make comparisons between various nano blending systems in terms of improved sustained and controlled drug release behavior.

An insight into the role of riboflavin ligand in the self-assembly of poly(lactic-co-glycolic acid)-based nanoparticles - a molecular simulation and experimental approach

Nanoparticles (NPs) used for targeted delivery purposes are rapidly gaining importance in diagnostic and therapeutic fields. These agents have been studied extensively so far to reveal their optimal physicochemical properties including the effects of ligands and their density on the surface of NPs. This article was conducted through a computational approach (all-atom molecular dynamics simulations) to predict the stability of NPs based on a poly-lactic-co-glycolic acid (PLGA) hydrophobic core with a poly-ethylene glycol (PEG) hydrophilic shell and varying numbers of riboflavin (RF) molecules as ligands. Depending on the molecular weight of the polymers, the most stable composition of NPs was achieved at 20 wt% and 10 wt% PLGA-PEG-RF for PLGA3kDa-PEG2kDa and PLGA4.5kDa-PEG2kDa polymers, respectively. According to the simulations, riboflavin molecules were located on the surface of the NPs, which would indicate that riboflavin-bound PLGA-PEG NPs could be efficiently utilized for active targeting purposes. To scrutinize the simulation results, NPs with riboflavin ligands were synthesized and put into in vitro experiments. Outstandingly, the empirical outcomes revealed that the hydrodynamic sizes of NPs also met minimum points at 20 and 10 wt% for PLGA3kDa-PEG2kDa and PLGA4.5kDa-PEG2kDa, respectively. Moreover, similar trends in the gyration radius as a function of riboflavin content were observed in the simulation analysis and the experimental results, which would indicate that the method of molecular dynamics (MD) simulation is a reliable mathematical technique and could be applied for predicting the physicochemical properties of NPs.

Anti-tumor effect of PEG-coated PLGA nanoparticles of febuxostat on A549 non-small cell lung cancer cells

In the present study, febuxostat (FBX)-loaded PEG-coated PLGA nanoparticles (FBX-PLGA-PEG) were developed and its anticancer activity on lung cancer cells was evaluated. FBX-PLGA-PEG were prepared by nanoprecipitation technique and characterized for particle size, size distribution, entrapment efficiency, and in vitro drug release study. The optimized formulations were used to evaluate cell viability, apoptosis, cell cycle, and caspase activity in A549 lung cancer cells. The optimized formulation showed spherical particle with average particle size of 180 ± 4.72 nm, particle-size distribution 0.223 ± 0.003, entrapment efficiency (70 ± 2.56%), and drug release (99.1 ± 2.33%) at 12 h. MTT cytotoxicity assay showed better cytotoxic potential of FBX-NPs than FBX solution against NSCLC A549 cells. The lower IC50 of FBX-NP (52.62 ± 2.52 µg/mL) compared to FBX (68.0 ± 4.12 µg/mL) are suggestive of a potential cytotoxic effect of nano-formulation compared to the drug itself. Furthermore, flow cytometry analysis showed significantly higher percentage of total apoptotic cells in FBX-NPs (10.38 ± 1.57%) as compared to FBX solution (2.76 ± 0.17%) showed strong proapoptotic potential of FBX nano-formulation. The increased caspase activity and percent of cells at G2/M phase of cell cycle increased for FBX nanoparticles were more effective than FBX solution in increasing caspase activity and percent of cells at G2/M phase of cell cycle. Our studies with FBX nanoparticles exhibited promising outcome which could be used as a strategies to combat lung cancer.

The Design of Poly(lactide-co-glycolide) Nanocarriers for Medical Applications

Polymeric biomaterials have found widespread applications in nanomedicine, and poly(lactide-co-glycolide), (PLGA) in particular has been successfully implemented in numerous drug delivery formulations due to its synthetic malleability and biocompatibility. However, the need for preconception in these formulations is increasing, and this can be achieved by selection and elimination of design variables in order for these systems to be tailored for their specific applications. The starting materials and preparation methods have been shown to influence various parameters of PLGA-based nanocarriers and their implementation in drug delivery systems, while the implementation of computational simulations as a component of formulation studies can provide valuable information on their characteristics. This review provides a critical summary of the synthesis and applications of PLGA-based systems in bio-medicine and outlines experimental and computational design considerations of these systems.

A pH-sensitive coordination polymer network-based nanoplatform for magnetic resonance imaging-guided cancer chemo-photothermal synergistic therapy

Developing various kinds of nanoplatforms with integrated diagnostic and therapeutic functions would be significant for imaging-guided precision treatment of cancer. However, it is still a challenge to organically integrate therapeutic and imaging components into a single nano-system rather than simply mixing. Herein, an iron-gallic acid network-based nanoparticle (Fe-GA@PEG-PLGA) was designed for magnetic resonance imaging (MRI)-guided chemo-photothermal synergistic therapy of tumors. The tumor spatial location and size information can be accurately achieved due to T₁ MRI based on Fe³⁺ coordination with GA in Fe-GA network. Furthermore, the nanoparticle exhibited extraordinary photostability and photothermal therapy capacity exceeded 42 °C within 100 s under 808 nm laser irradiation. Meanwhile, the Fe-GA polymeric network can be disassembled in tumor acidic environment and the released drug GA can induce apoptosis. This study demonstrated that the Fe-GA network-based nanoparticle is a promising diagnostic and therapeutic agent for theranostic application and further clinic translation.

Influence of PEGylation on PLGA nanoparticle properties, hydrophobic drug release and interactions with human serum albumin

Objective

To evaluate the impact of PEG content on poly(lactic-co-glycolic acid) (PLGA) NP physicochemical properties, hydrophobic drug release (rifampicin as a model drug) and human serum protein binding.

Methods

Rifampicin loaded and unloaded nanoparticles with PEG content of 0–17% (w/w) were prepared by an emulsification–evaporation technique. Nanoparticles were characterized for size, zeta potential and morphology. PEGlyation was confirmed using proton nuclear magnetic resonance (1H NMR). Fluorescence spectroscopy and dynamic light scattering were used to determine nanoparticle-protein binding, binding constants and stability of nanoparticles in human serum, respectively. Drug loading and release were determined by UV-VIS spectroscopy and drug release data was mathematically modelled.

Key findings

A NP PEG content of 17% w/w significantly retarded release of rifampicin from PLGA NPs and altered kinetics of drug release. Stern–Volmer (Ksv) protein binding constants decreased upon PEG incorporation. A 2% w/w PEG was sufficient to significantly reduce protein binding extent to PLGA NPs and maintain particle size distributions.

Conclusion

The ability to fine tune drug release and formation of protein corona around nanoparticles is crucial to formulation scientists. This study suggests that PLGA NPs with low PEG content might be suitable for extended circulation and rapid drug release and that higher PEG content retards hydrophobic drug release.

Fabrication of redox-responsive Bi(mPEG-PLGA)-Se2 micelles for doxorubicin delivery

Stimuli-responsive polymeric nanostructures have emerged as potential drug carriers for cancer therapy. Herein, we synthesized redox-responsive diselenide bond containing amphiphilic polymer, Bi(mPEG-PLGA)-Se₂ from mPEG-PLGA and 3,3'-diselanediyldipropanoic acid (DSeDPA) using DCC/DMAP as coupling agents. Due to its amphiphilic nature, Bi(mPEG-PLGA)-Se₂ self-assembled in to stable micelles in aqueous solution with a hydrodynamic size of 123.9 ± 0.85 nm. The Bi(mPEG-PLGA)-Se₂ micelles exhibited DOX-loading content (DLC) of 6.61 wt% and encapsulation efficiency (EE) of 54.9%. The DOX-loaded Bi(mPEG-PLGA)-Se₂ micelles released 73.94% and 69.54% of their cargo within 72 h upon treatment with 6 mM GSH and 0.1% H₂O₂, respectively, at pH 7.4 and 37 °C. The MTT assay results demonstrated that Bi(mPEG-PLGA)-Se₂ was devoid of any inherent toxicity and the DOX-loaded micelles showed pronounced antitumor activities against HeLa cells, 44.46% of cells were viable at maximum dose of 7.5 µg/mL. The cellular uptake experiment further confirmed the internalization of DOX-loaded Bi(mPEG-PLGA)-Se₂ micelles and endowed redox stimuli triggered drug release in cytosol and nuclei of cancer cells. Overall, the results suggested that the smart, biocompatible Bi(mPEG-PLGA)-Se₂ copolymer could serve as potential drug delivery biomaterial for the controlled release of hydrophobic drugs in cancer cells.