Engineering lauric acid-based nanodrug delivery systems for restoring chemosensitivity and improving biocompatibility of 5-FU and OxPt against Fn-associated colorectal tumor

Colorectal cancer (CRC) occurs in the colorectum and ranks second in the global incidence of all cancers, accounting for one of the highest mortalities. Although the combination chemotherapy regimen of 5-fluorouracil (5-FU) and platinum(IV) oxaliplatin prodrug (OxPt) is an effective strategy for CRC treatment in clinical practice, chemotherapy resistance caused by tumor-resided Fusobacterium nucleatum (Fn) could result in treatment failure. To enhance the efficacy and improve the biocompatibility of combination chemotherapy, we developed an antibacterial-based nanodrug delivery system for Fn-associated CRC treatment. A tumor microenvironment-activated nanomedicine 5-FU-LA@PPL was constructed by the self-assembly of chemotherapeutic drug derivatives 5-FU-LA and polymeric drug carrier PPL. PPL is prepared by conjugating lauric acid (LA) and OxPt to hyperbranched polyglycidyl ether. In principle, LA is used to selectively combat Fn, inhibit autophagy in CRC cells, restore chemosensitivity of 5-FU as well as OxPt, and consequently enhance the combination chemotherapy effects for Fn-associated drug-resistant colorectal tumor. Both in vitro and in vivo studies exhibited that the tailored nanomedicine possessed efficient antibacterial and anti-tumor activities with improved biocompatibility and reduced non-specific toxicity. Hence, this novel anti-tumor strategy has great potential in the combination chemotherapy of CRC, which suggests a clinically relevant valuable option for bacteria-associated drug-resistant cancers.

Remotely Controllable Supramolecular Nanomedicine for Drug-Resistant Colorectal Cancer Therapy Caused by Fusobacterium nucleatum

Fusobacterium nucleatum (Fn) existing in the community of colorectal cancer (CRC) promotes CRC progression and causes chemotherapy resistance. Despite great efforts that have been made to overcome Fn-induced chemotherapy resistance by co-delivering antibacterial agents and chemotherapeutic drugs, increasing the drug-loading capacity and enabling controlled release of drugs remain challenging. In this study, a novel supramolecular upconversion nanoparticle (SUNP) is constructed by incorporating a positively charged polymer (PAMAM-LA-CD) with Fn inhibition capacity, a negatively charged platinum (IV) oxaliplatin prodrug (OXA-COOH), upconversion nanoparticle (UCNPs) and polyethylene glycol-azobenzene (PEG-Azo) to enhance drug-loading and enable on-demand drug release for drug-resistant CRC treatment. SUNPs exhibit high drug-loading capacity (30.8%) and good structural stability under normal physiological conditions, while disassembled upon exogenous NIR excitation and endogenous azo reductase in the CRC microenvironment to trigger drug release. In vitro and in vivo studies demonstrate that SUNPs presented good biocompatibility and robust performance to overcome chemoresistance, thereby significantly inhibiting Fn-infected cancer cell proliferation. This study leverages multiple dynamic chemical designs to integrate both advantages of drug loading and release in a single system, which provides a promising candidate for precision therapy of bacterial-related drug-resistant cancers.

The Implication of Growth Arrest-Specific 5 rs145204276 Polymorphism and Serum Expression of Sirtuin 1, Transforming Growth Factor-Beta, and microRNA-182 in Breast Cancer

Background

Breast cancer (BC) patients have a higher chance of survival if it is diagnosed at an early stage, which is essential for efficient treatment of the condition. The results of an elevated risk of cancer, including BC, previously associated with the ins/del polymorphism rs145204276 in the promoter region of growth arrest-specific 5 (GAS5) are still up for debate. Thus, this study aimed to appraise the frequency of the GAS5 rs145204276 variant with BC risk and demonstrate the potential impact of the sirtuin 1 (SIRT-1), transforming growth factor-beta (TGF-β), and microRNA-182 (miR-182) expression and their diagnostic value in BC.

Methods

Blood samples of 155 patients with BC and fibroadenoma and 80 healthy controls were analyzed for GAS5 rs145204276 single nucleotide polymorphism (SNP), SIRT-1, TGF-β, and miRNA-182 expression levels.

Results

Ins/ins genotype and ins allele frequencies for GAS5 rs145204276 were considerably higher in BC patients compared with controls. Patients with BC had significantly greater serum levels of TGF-β, miR-182, and SIRT-1 expression.

Conclusions

The SIRT-1, TGF-β, and miR-182 genes provide novel, noninvasive diagnostic biomarkers for BC.

Electrospun Tamarindus indica-loaded antimicrobial PMMA/cellulose acetate/PEO nanofibrous scaffolds for accelerated wound healing: In-vitro and in-vivo assessments

In this work, Tamarindus indica (T. indica)-loaded crosslinked poly(methyl methacrylate) (PMMA)/cellulose acetate (CA)/poly(ethylene oxide) (PEO) electrospun nanofibers were designed and fabricated for wound healing applications. T. indica is a plant extract that possesses antidiabetic, antimicrobial, antioxidant, antimalarial and wound healing properties. T. indica leaves extract of different concentrations were blended with a tuned composition of a matrix comprised of PMMA (10 %), CA (2 %) and PEO (1.5 %), and were electrospun to form smooth, dense and continuous nanofibers as illustrated by SEM investigation. In vitro evaluation of T. indica-loaded nanofibers on normal human skin fibroblasts (HBF4) revealed a high compatibility and low cytotoxicity. T. indica-loaded nanofibers significantly increased the healing activity of scratched HBF4 cells, as compared to the free plant extract, and the healing activity was significantly enhanced upon increasing the plant extract concentration. Moreover, T. indica-loaded nanofibers demonstrated significant antimicrobial activity in vitro against the tested microbes. In vivo, nanofibers resulted in a superior wound healing efficiency compared to the control untreated animals. Hence, engineered nanofibers loaded with potent phytochemicals could be exploited as an effective biocompatible and eco-friendly antimicrobial biomaterials and wound healing composites.

In vitro and in vivo studies of Syzygium cumini-loaded electrospun PLGA/PMMA/collagen nanofibers for accelerating topical wound healing

This work aims to develop plant extract-loaded electrospun nanofiber as an effective wound dressing scaffolds for topical wound healing. Electrospun nanofibers were fabricated from Syzygium cumini leaf extract (SCLE), poly(lactic-co-glycolic acid) (PLGA), poly(methyl methacrylate) (PMMA), collagen and glycine. Electrospinning conditions were optimized to allow the formation of nanosized and uniform fibers that display smooth surface. Morphology and swelling behavior of the formed nanofibers were studied. In addition, the antibacterial activity of the nanofibers against multidrug-resistant and human pathogens was assessed by agar-well diffusion. Results showed that nanofibers containing Syzygium cumini extract at concentrations of 0.5 and 1% w/v exhibited greater antibacterial activity against the tested Gram-positive (i.e., Staphylococcus aureus, Candida albicans, Candida glabrata and Bacillus cereus) and Gram-negative (i.e., Salmonella paratyphi and Escherichia coli) pathogens compared to the same concentrations of the plain extract. Furthermore, in vivo wound healing was evaluated in Wistar rats over a period of 14 days. In vivo results demonstrated that nanofiber mats containing SCLE and collagen significantly improved wound healing within two weeks, compared to the control untreated group. These findings highlight the potential of fabricated nanofibers in accelerating wound healing and management of topical acute wounds.

Oral proniosomal amitriptyline and liraglutide for management of diabetic neuropathy: Exceptional control over hyperglycemia and neuropathic pain

Exploitation of nanocarriers provides a compartment for enclosing drugs to protect them from degradation and potentiate their therapeutic efficiency. In the current study, amitriptyline- and liraglutide-loaded proniosomes were constructed for management of diabetic neuropathy, a serious complication associated with diabetes, that triggers spontaneous pain in patients and results in impaired quality of life. The developed therapeutic proniosomes were extensively characterized via dynamic light scattering, scanning electron microscopy, transmission electron microscopy, and Fourier transform-infrared spectroscopy. High entrapment efficiency could be attained for both drugs in the proniosomes, and the reconstituted amitriptyline- and liraglutide-loaded niosomes possessed spherical morphology and particle sizes of 585.3 nm and 864.4 nm, respectively. In a diabetic neuropathy rat model, oral administration of the developed amitriptyline- and liraglutide-loaded proniosomes significantly controlled blood glucose levels, reduced neuropathic pain, oxidative stress and inflammatory markers, and improved histological structure of the sciatic nerve as compared to the oral and subcutaneous administration of amitriptyline and liraglutide, respectively. Loading of the tricyclic antidepressant amitriptyline and the antidiabetic peptide liraglutide into proniosomes resulted in exceptional control over hyperglycemia and neuropathic pain, and thus could provide an auspicious delivery system for management of neuropathic pain and control of blood glucose levels.

Machine learning algorithms for prediction of entrapment efficiency in nanomaterials

Exploitation of machine learning in predicting performance of nanomaterials is a rapidly growing dynamic area of research. For instance, incorporation of therapeutic cargoes into nanovesicles (i.e., entrapment efficiency) is one of the critical parameters that ensures proper entrapment of drugs in the developed nanosystems. Several factors affect the entrapment efficiency of drugs and thus multiple assessments are required to ensure drug retention, and to reduce cost and time. Supervised machine learning can allow for the construction of algorithms that can mine data available from earlier studies to predict performance of specific types of nanoparticles. Comparative studies that utilize multiple regression algorithms to predict entrapment efficiency in nanomaterials are scarce. Herein, we report on a detailed methodology for prediction of entrapment efficiency in nanomaterials (e.g., niosomes) using different regression algorithms (i.e., CatBoost, linear regression, support vector regression and artificial neural network) to select the model that demonstrates the best performance for estimation of entrapment efficiency. The study concluded that CatBoost algorithm demonstrated the best performance with maximum R2 score (0.98) and mean square error (< 10-4). Among the various parameters that possess a role in entrapment efficiency of drugs into niosomes, the results obtained from CatBoost model revealed that the drug:lipid ratio is the major contributing factor affecting entrapment efficiency, followed by the lipid:surfactant molar ratio. Hence, supervised machine learning may be applied for future selection of the components of niosomes that achieve high entrapment efficiency of drugs while minimizing experimental procedures and cost.

Development and in vivo evaluation of therapeutic phytosomes for alleviation of rheumatoid arthritis

Rheumatoid arthritis (RA) is a chronic inflammatory autoimmune disease associated with progressive articular damage, functional loss and comorbidity. Conventional RA therapy requires frequent dosing and prolonged use, and usually results in poor efficacy and severe toxicity. In the current study, for the first time, we describe a combination strategy using phytosomes co-loaded with curcumin (CUR) and leflunomide (LEF) to improve the clinical outcomes of RA therapy. Exploiting 23 factorial design, various compositions of CUR and LEF co-loaded phytosomes (CUR/LEF-phytosomes) were successfully prepared and were extensively characterized (e.g., particle size, zeta potential, drugs encapsulation efficiency, morphology, DSC, FTIR and release kinetics). The optimal CUR/LEF-loaded phytosomes (F2) demonstrated high stability and spherical morphology with a particle size of ca. 760 nm and negative zeta potential value of - 55.7, high entrapment for both drugs, and sustained release profile of the entrapped medications. In vivo, oral administration of the CUR/LEF-phytosomes (F2) in arthritic rats resulted in significant reduction of paw swelling and inflammatory markers, compared to the free drugs and their physical mixture. Histopathological examination revealed significant improvement in phytosomes-treated animal group with no signs of arthritis. CUR/LEF-loaded phytosomes provide an auspicious strategy for alleviation of RA.

Nano-ciprofloxacin/meropenem exhibit bactericidal activity against Gram-negative bacteria and rescue septic rat model

Aim: We hypothesized that simultaneous administration of two antibiotics loaded into a nanopolymer matrix would augment their synergistic bactericidal interaction. Methods: Nanoplatforms of chitosan/Pluronic® loaded with ciprofloxacin/meropenem (CS/Plu-Cip/Mer) were prepared by the ionic gelation method, using Plu at concentrations in the range 0.5-4% w/v. CS/Plu-Cip/Mer was evaluated for antibacterial synergistic activity in vitro and in vivo. Results: CS/Plu-Cip and CS/Plu-Mer with Plu concentrations of 3% w/v and 2% w/v, respectively, exhibited ∼80% encapsulation efficiency. The MICs of pathogens were fourfold to 16-fold lower for CS/Plu-Cip/Mer than for Cip/Mer. Synergy was evidenced for CS/Plu-Cip/Mer with a bactericidal effect (at 1× MIC and sub-MICs), and it significantly decreased bacterial load and rescued infected rats. Conclusion: This study illustrates the ability of CS/Plu nanopolymer to intensify synergy between antibiotics, thereby providing a promising potential to rejuvenate antibiotics considered ineffective against resistant pathogens.

Morphologic Design of Nanogold Carriers for a Carbonic Anhydrase Inhibitor: Effect on Ocular Retention and Intraocular Pressure

Morphologic design of nanomaterials for a diversity of biomedical applications is of increasing interest. The aim of the current study is to construct therapeutic gold nanoparticles of different morphologies and investigate their effect on ocular retention and intraocular pressure in a glaucoma rabbit model. Poly(lactic-co-glycolic acid) (PLGA)-coated nanorods and nanospheres have been synthesized and loaded with carbonic anhydrase inhibitor (CAI), and characterized in vitro for their size, zeta potential and encapsulation efficiency. Nanosized PLGA-coated gold nanoparticles of both morphologies demonstrated high entrapment efficiency (˃ 98%) for the synthesized CAI and the encapsulation of the drug into the developed nanoparticles was confirmed via Fourier transform-infrared spectroscopy. In vivo studies revealed a significant reduction in intraocular pressure upon instillation of drug-loaded nanogold formulations compared to the marketed eye drops. Spherical nanogolds exhibited a superior efficacy compared to the rod-shaped counterparts, probably due to the enhanced ocular retention of spherical nanogolds within collagen fibers of the stroma, as illustrated by transmission electron microscopy imaging. Normal histological appearance was observed for the cornea and retina of the eyes treated with spherical drug-loaded nanogolds. Hence, incorporation of a molecularly-designed CAI into nanogold of tailored morphology may provide a promising strategy for management of glaucoma.

In situ-activated photothermal nanoplatform for on-demand NO gas delivery and enhanced colorectal cancer treatment

The naturally evolved and intestinal pathogenic Fusobacterium nucleatum (Fn)-induced drug resistance profoundly impaired the efficacy of chemotherapy against colorectal cancer (CRC). Alternative treatment modalities against Fn-associated CRC are desperately needed. Herein, we engineer an in situ-activated anti-tumor and antibacterial nanoplatform (Cu₂O/BNN6@MSN-Dex) to allow photoacoustic (PA) imaging-guided photothermal and NO gas combinatorial therapy for enhanced Fn-associated CRC treatment. The nanoplatform is constructed by loading cuprous oxide (Cu₂O) and nitric oxide (NO) donor (BNN6) into dextran-decorated mesoporous silica nanoparticles (MSN), which is finally surface-functionalized with dextran via dynamic boronate linkage. Cu₂O can be sulfuretted in situ by endogenous hydrogen sulfide overexpressed in CRC to produce copper sulfide with remarkable PA and photothermal properties, enabling the generation of NO from BNN6 under 808 nm laser irradiation, which is eventually triggered to release by multiple biological cues in the tumor microenvironment. Cu₂O/BNN6@MSN-Dex exhibits superior biocompatibility, as well as H₂S-triggered near-infrared-controlled antibacterial and anti-tumor performance in vitro and in vivo via photothermal and NO gas combination therapy. Furthermore, Cu₂O/BNN6@MSN-Dex provokes systemic immune responses, thereby promoting anti-tumor efficacy. This study provides a conbinational strategy to effectively inhibit tumors and intratumor pathogens for enhanced CRC treatment.

Effective loading of incompatible drugs into nanosized vesicles: a strategy to allow concurrent administration of furosemide and midazolam in simulated clinical settings

The current study aims to assess the use of nanocarriers to limit drug incompatibilities in clinical settings, and thus eliminating serious clinical consequences (e.g., catheter obstruction and embolism), and enhancing in vivo bioavailability and efficacy. As a proof-of-concept, the impact of loading well-documented physically incompatible drugs (i.e., furosemide and midazolam) into nanosized vesicles on in vitro stability and in vivo bioavailability of the two drugs was investigated. Furosemide and midazolam were loaded into nanosized spherical vesicles at high entrapment efficiency (ca. 62-69%). The drug-loaded vesicles demonstrated a sustained drug release patterns, high physical stability and negligible hemolytic activity. Physical incompatibility was assessed by exploiting microscopic technique coupled with image processing and analysis, dynamic light scattering and laser Doppler anemometry. Incorporation of drugs separately inside the nanosized vesicles dramatically decreased size and number of the precipitated particles. In vivo, the niosomal drug mixture demonstrated a significant improvement in pharmacokinetic profiles of furosemide and midazolam compared to the mixed free drug solutions, as evidenced by their longer circulation half-lives and higher area under the plasma-concentration time curves of both drugs. Nanocarriers could provide an auspicious strategy for circumventing drug incompatibilities, thus reducing adverse reactions, hospitalization period and improving therapeutic outcomes.

Morphologic design of nanostructures for enhanced antimicrobial activity

Despite significant progress in synthetic polymer chemistry and in control over tuning the structures and morphologies of nanoparticles, studies on morphologic design of nanomaterials for the purpose of optimizing antimicrobial activity have yielded mixed results. When designing antimicrobial materials, it is important to consider two distinctly different modes and mechanisms of activity-those that involve direct interactions with bacterial cells, and those that promote the entry of nanomaterials into infected host cells to gain access to intracellular pathogens. Antibacterial activity of nanoparticles may involve direct interactions with organisms and/or release of antibacterial cargo, and these activities depend on attractive interactions and contact areas between particles and bacterial or host cell surfaces, local curvature and dynamics of the particles, all of which are functions of nanoparticle shape. Bacteria may exist as spheres, rods, helices, or even in uncommon shapes (e.g., box- and star-shaped) and, furthermore, may transform into other morphologies along their lifespan. For bacteria that invade host cells, multivalent interactions are involved and are dependent upon bacterial size and shape. Therefore, mimicking bacterial shapes has been hypothesized to impact intracellular delivery of antimicrobial nanostructures. Indeed, designing complementarities between the shapes of microorganisms with nanoparticle platforms that are designed for antimicrobial delivery offers interesting new perspectives toward future nanomedicines. Some studies have reported improved antimicrobial activities with spherical shapes compared to non-spherical constructs, whereas other studies have reported higher activity for non-spherical structures (e.g., rod, discoid, cylinder, etc.). The shapes of nano- and microparticles have also been shown to impact their rates and extents of uptake by mammalian cells (macrophages, epithelial cells, and others). However, in most of these studies, nanoparticle morphology was not intentionally designed to mimic specific bacterial shape. Herein, the morphologic designs of nanoparticles that possess antimicrobial activities per se and those designed to deliver antimicrobial agent cargoes are reviewed. Furthermore, hypotheses beyond shape dependence and additional factors that help to explain apparent discrepancies among studies are highlighted.

Ameliorative effect of chitosan nanoparticles against carbon tetrachloride-induced nephrotoxicity in Wistar rats

CONTEXT

Chitosan is a biocompatible polysaccharide that has been widely exploited in biomedical and drug delivery applications.

OBJECTIVE

This study explores the renoprotective effect of chitosan nanoparticles in vivo in rats.

MATERIALS AND METHODS

Chitosan nanoparticles were prepared via ionotropic gelation method, and several in vitro characterizations were performed, including measurements of particle size, zeta potential, polydispersity index, Fourier transform-infrared spectroscopy, differential scanning calorimetry, and transmission electron microscopy (TEM) imaging. Wistar rats were divided randomly into four groups; negative control, CCl₄-induced nephrotoxicity (untreated), and two groups receiving CCl₄ + chitosan NPs (10 and 20 mg/kg) orally for 2 weeks. The renoprotective effect was assessed by measuring oxidative, apoptotic, and inflammatory biomarkers, and via histopathological and immunohistochemical examinations for the visualization of NF-κB and COX-2 in renal tissues.

RESULTS

Monodisperse spherical nanosized (56 nm) particles were successfully prepared as evidenced by dynamic light scattering and TEM. Oral administration of chitosan nanoparticles (10 and 20 mg/kg) concurrently with CCl₄ for 2 weeks resulted in 13.6% and 21.5% reduction in serum creatinine and increase in the level of depleted reduced glutathione (23.1% and 31.8%), respectively, when compared with the positive control group. Chitosan nanoparticles (20 mg/kg) revealed a significant (p ˂ 0.05) decrease in malondialdehyde levels (30.6%), tumour necrosis factor-α (33.6%), interleukin-1β (31.1%), and caspase-3 (36.6%).

CONCLUSIONS

Chitosan nanoparticles afforded significant protection and amelioration against CCl₄-induced nephrotoxicity. Thus, chitosan nanoparticles could afford a potential nanotherapeutic system for the management of nephrotoxicity which allows for broadening their role in biomedical delivery applications.

Design of nanoconstructs that exhibit enhanced hemostatic efficiency and bioabsorbability

Hemorrhage is a prime cause of death in civilian and military traumatic injuries, whereby a significant proportion of death and complications occur prior to paramedic arrival and hospital resuscitation. Hence, it is crucial to develop hemostatic materials that are able to be applied by simple processes and allow control over bleeding by inducing rapid hemostasis, non-invasively, until subjects receive necessary medical care. This tutorial review discusses recent advances in synthesis and fabrication of degradable hemostatic nanomaterials and nanocomposites. Control of assembly and fine-tuning of composition of absorbable (i.e., degradable) hemostatic supramolecular structures and nanoconstructs have afforded the development of smart devices and scaffolds capable of efficiently controlling bleeding while degrading over time, thereby reducing surgical operation times and hospitalization duration. The nanoconstructs that are highlighted have demonstrated hemostatic efficiency pre-clinically in animal models, while also sharing characteristics of degradability, bioabsorbability and presence of nano-assemblies within their compositions.

Sesamol Loaded Albumin Nanoparticles: A Boosted Protective Property in Animal Models of Oxidative Stress

The current study evaluated the ability of sesamol-loaded albumin nanoparticles to impart protection against oxidative stress induced by anthracyclines in comparison to the free drug. Albumin nanoparticles were prepared via the desolvation technique and then freeze-dried with the cryoprotectant, trehalose. Albumin concentration, pH, and type of desolvating agent were assessed as determining factors for successful albumin nanoparticle fabrication. The optimal nanoparticles were spherical in shape, and they had an average particle diameter of 127.24 ± 2.12 nm with a sesamol payload of 96.89 ± 2.4 μg/mg. The drug cellular protection was tested on rat hepatocytes pretreated with 1 µM doxorubicin, which showed a 1.2-fold higher protective activity than the free sesamol. In a pharmacokinetic study, the loading of a drug onto nanoparticles resulted in a longer half-life and mean residence time, as compared to the free drug. Furthermore, in vivo efficacy and biochemical assessment of lipid peroxidation, cardiac biomarkers, and liver enzymes were significantly ameliorated after administration of the sesamol-loaded albumin nanoparticles. The biochemical assessments were also corroborated with the histopathological examination data. Sesamol-loaded albumin nanoparticles, prepared under controlled conditions, may provide an enhanced protective effect against off-target doxorubicin toxicity.

Development of potent nanosized isatin-isonicotinohydrazide hybrid for management of Mycobacterium tuberculosis

Inspired by the antitubercular activity of isoniazid (INH) and 5-bromoisatin, isatin-INH hybrid (WF-208) has been synthesized as a potent agent against multidrug-resistant (MDR) and extensively drug-resistant (XDR) strains of M. tuberculosis. In silico molecular docking studies indicated that DprE1, a critical enzyme in the synthesis of M. tuberculosis cell wall, is a potential enzymatic target for WF-208. The synthesized WF-208 was incorporated into a nanoparticulate system to enhance stability of the compound and to sustain its antimicrobial effect. Nanosized spherical niosomes (hydrodynamic diameter of ca. 500-600 nm) could accommodate WF-208 at a high encapsulation efficiency of 74.2%, and could impart superior stability to the compound in simulated gastric conditions. Interestingly, WF-208 had minimal inhibitory concentrations (MICs) of 7.8 and 31.3 µg/mL against MDR and XDR M. tuberculosis, respectively, whereas INH failed to demonstrate bacterial growth inhibition at the range of the tested concentrations. WF-208-loaded niosomes exhibited a 4-fold increase in the anti-mycobacterial activity as compared to the free compound (MIC of 1.9 vs. 7.8 µg/mL) against H37Rv M. tuberculosis, after three weeks of incubation with WF-208-loaded niosomes. Incorporation of the compound into nanosized vesicles allowed for a further increase in stability, potency and sustainability of the anti-mycobacterial activity, thus, providing a promising strategy for management of tuberculosis.

Famotidine-loaded solid self-nanoemulsifying drug delivery system demonstrates exceptional efficiency in amelioration of peptic ulcer

Famotidine (FMD) is a highly potent H₂-receptor antagonist used in peptic ulcer treatment. However, the drug possesses poor aqueous solubility and permeability. FMD-loaded solid self-nanoemulsifying drug delivery system (FMD-S-SNEDDS) comprised of Labrafil® M 1944 CS, Tween® 20 and PEG 400, adsorbed on Aerosil® 200, has been developed. FMD-S-SNEDDS has demonstrated acceptable micromeritic properties, and upon reconstitution in water, spherical nanosized particles were released, as demonstrated by dynamic light scattering studies and transmission electron microscopy imaging. High encapsulation efficiency of FMD in the developed SNEDDS has been attained, and the saturated solubility of the drug has increased by 20-fold when it was incorporated in the SNEDDS. Several in vitro characterizations have been carried out, including, Fourier transform-infrared spectroscopy, differential scanning calorimetry, scanning electron microscopy, and drug dissolution studies. In vivo, upon administration of the free drug suspension, marketed product (FAMOTIN®) and FMD-S-SNEDDS (40 mg/kg) in peptic ulcer rat models, FMD-S-SNEDDS and the marketed FMD demonstrated 12.5- and 4.7-fold reduction in ulcers number, and 28.7- and 7.2-fold reduction in ulcer severity, respectively, compared to the control untreated animals. FMD-S-SNEDDS showed a significant (p < 0.05) increase in the levels of depleted glutathione and endothelial nitric oxide synthase, and significantly (p < 0.05) reduced the elevated level of malondialdehyde, as compared to the free and marketed FMD. Only FMD-S-SNEDDS could restore the elevated proton pump activity and cyclic adenosine monophosphate RNA expression to their normal levels. Hence, FMD-S-SNEDDS provides a great potential as a nanotherapeutic system for treatment of peptic ulcer.

Applications of nanoengineered therapeutics and vaccines: special emphasis on COVID-19

Nanomedicine provides innovative strategies that had significantly improved drug and gene delivery and allowed control over the engineering of therapeutics, diagnostics, vaccines, and other medical devices, for a diversity of medical applications. This review focuses on the current attempts to develop potent nanoengineered vaccines and therapeutics against coronaviruses, and the recent fabrication strategies and design principles to control acute infections from the escalating SARS-CoV-2 pandemic. Nanomedical approaches provide versatile platforms that can be utilized to enhance the overall potency, safety, and stability of vaccines, thus augmenting the desired immune response. Their modulable conformational features of size, shape, surface charge, antigen display, and composition allow for precise tuning and optimization of the nanoconstructs for the management of a variety of diseases and pathological conditions. The ability to control the release of their encapsulated cargoes and the possibility of surface decoration with various moieties support the construction of multifunctional nanomaterials that ultimately boost and prolong the immune response elicited and/or therapeutic effects, selectively at the diseased tissues and target sites.

A dendritic polyamidoamine supramolecular system composed of pillar[5]arene and azobenzene for targeting drug-resistant colon cancer

Fusobacterium nucleatum caused drug-resistant around tumor sites often leads to the failure of chemotherapy during colorectal cancer (CRC) treatment. Multifunctional cationic quaternary ammonium materials have been widely used as broad-spectrum antibacterial agents in antibacterial and anticancer fields. Herein, we design a smart supramolecular quaternary ammonium nanoparticle, namely quaternary ammonium PAMAM-AZO@CP[5]A (Q-P-A@CP[5]A), consisting of azobenzene (AZO)-conjugated dendritic cationic quaternary ammonium polyamidoamine (PAMAM) as the core and carboxylatopillar[5]arene (CP[5]A)-based switch, for antibacterial and anti-CRC therapies. The quaternary ammonium-PAMAM-AZO (Q-P-A) core endows the supramolecular system with enhanced antibacterial and anticancer properties. -N⁺CH₃ groups on the surface of Q-P-A are accommodated in the CP[5]A cavity under normal conditions, which significantly improves the biocompatibility of Q-P-A@CP[5]A. Meanwhile, the CP[5]A host can be detached from -N⁺CH₃ groups under pathological conditions, achieving efficient antibacterial and antitumor therapies. Furthermore, azoreductase in the tumor site can break the -NN- bonds of AZO in Q-P-A@CP[5]A, leading to the morphology recovery of supramolecular nanoparticles and CRC therapy through inducing cell membrane rupture. Both in vitro and in vivo experiments demonstrate that Q-P-A@CP[5]A possesses good biocompatibility, excellent antibacterial effect, and CRC treatment capability with negligible side effects. This supramolecular quaternary ammonium system provides an effective treatment method to overcome chemotherapy-resistant cancer caused by bacteria.

Intratracheal Administration of Chloroquine-Loaded Niosomes Minimize Systemic Drug Exposure

Pulmonary administration provides a useful alternative to oral and invasive routes of administration while enhancing and prolonging the accumulation of drugs into the lungs and reducing systemic drug exposure. In this study, chloroquine, as a model drug, was loaded into niosomes for potential pulmonary administration either via dry powder inhalation or intratracheally. Chloroquine-loaded niosomes have been prepared and extensively characterized. Furthermore, drug-loaded niosomes were lyophilized and their flowing properties were evaluated by measuring the angle of repose, Carr's index, and Hausner ratio. The developed niosomes demonstrated a nanosized (100-150 nm) spherical morphology and chloroquine entrapment efficiency of ca. 24.5%. The FT-IR results indicated the incorporation of chloroquine into the niosomes, whereas in vitro release studies demonstrated an extended-release profile of the drug-loaded niosomes compared to the free drug. Lyophilized niosomes exhibited poor flowability that was not sufficiently improved after the addition of lactose or when cryoprotectants were exploited throughout the lyophilization process. In vivo, intratracheal administration of chloroquine-loaded niosomes in rats resulted in a drug concentration in the blood that was 10-fold lower than the oral administration of the free drug. Biomarkers of kidney and liver functions (i.e., creatinine, urea, AST, and ALT) following pulmonary administration of the drug-loaded nanoparticles were of similar levels to those of the control untreated animals. Hence, the use of a dry powder inhaler for administration of lyophilized niosomes is not recommended, whereas intratracheal administration might provide a promising strategy for pulmonary administration of niosomal dispersions while minimizing systemic drug exposure and adverse reactions.

Morphologic Design of Silver-Bearing Sugar-Based Polymer Nanoparticles for Uroepithelial Cell Binding and Antimicrobial Delivery

Platelet-like and cylindrical nanostructures from sugar-based polymers are designed to mimic the aspect ratio of bacteria and achieve uroepithelial cell binding and internalization, thereby improving their potential for local treatment of recurrent urinary tract infections. Polymer nanostructures, derived from amphiphilic block polymers composed of zwitterionic poly(d-glucose carbonate) and semicrystalline poly(l-lactide) segments, were constructed with morphologies that could be tuned to enhance uroepithelial cell binding. These nanoparticles exhibited negligible cytotoxicity, immunotoxicity, and cytokine adsorption, while also offering substantial silver cation loading capacity, extended release, and in vitro antimicrobial activity (as effective as free silver cations) against uropathogenic Escherichia coli. In comparison to spherical analogues, cylindrical and platelet-like nanostructures engaged in significantly higher association with uroepithelial cells, as measured by flow cytometry; despite their larger size, platelet-like nanostructures maintained the capacity for cell internalization. This work establishes initial evidence of degradable platelet-shaped nanostructures as versatile therapeutic carriers for treatment of epithelial infections.

Methods for preparation of nanostructured lipid carriers

Construction of nanocarriers of different structures and properties have shown great promise as delivery systems for a wide range of drugs to improve therapeutic effects and reduce side effects. Nanostructured lipid carriers (NLCs) have been introduced as a new generation of solid lipid nanoparticles (SLNs) to overcome several of the limitations associated with the SLNs. NLCs consist of a blend of solid and liquid lipids which result in a partially crystallized lipid system that enables higher drug loading efficiency compared to SLNs. Owing to their biocompatibility, low toxicity, ease of preparation and scaling-up, and high stability, NLCs have been exploited in numerous pharmaceutical applications. Different methods for fabrication of NLCs have been described in the literature. In this article, procedures involved in emulsification-solvent evaporation method, one of the commonly utilized methods for preparation of NLCs, are described in detail. Critical aspects that should be considered throughout preparation process are also highlighted to allow for consistent and reproducible construction of NLCs.

Methods for preparation of niosomes: A focus on thin-film hydration method

Development of nanocarriers has opened new avenues for the delivery of therapeutics of various pharmacological activities with improved targeting properties and reduced side effects. Niosomes, non-ionic-based vesicles, have drawn much interest in various biomedical applications, owing to their unique characteristics and their ability to encapsulate both hydrophilic and lipophilic cargoes. Niosomes share structural similarity with liposomes while overcoming limitations associated with stability, sterilization, and large-scale production of liposomes. Different methods for preparation of niosomes have been described in the literature, each having its own merits and a great impact on the sizes and characteristics of the formed niosomes. In this article, procedures involved in the thin-film hydration method, a commonly used method for the preparation of niosomes, are described in detail, while highlighting precautions that should be considered for consistent and reproducible construction of niosomes.

Morphologic design of sugar-based polymer nanoparticles for delivery of antidiabetic peptides

Zwitterionic polymer nanoparticles of diverse morphologies (spherical, cylindrical, and platelet-like) constructed from biocompatible sugar-based polymers are designed to extend the pharmacological activities of short- and long-acting insulin peptides, thereby providing potential for therapeutic systems capable of reducing the frequency of administration and improving patient compliance. Amphiphilic block copolymers composed of zwitterionic poly(d-glucose carbonate) and semicrystalline polylactide segments were synthesized, and the respective block length ratios were tuned to allow formation of nanoscopic assemblies having different morphologies. Insulin-loaded nanoparticles had similar sizes and morphologies to the unloaded nanoparticle counterparts. Laser scanning confocal microscopy imaging of three-dimensional spheroids of vascular smooth muscle cells and fibroblasts after treatment with LIVE/DEAD® stain and FITC-insulin-loaded nanoparticles demonstrated high biocompatibility for the nanoconstructs of the various morphologies and significant intracellular uptake of insulin in both cell lines, respectively. Binding of short-acting insulin and long-acting insulin glargine to nanoparticles resulted in extended hypoglycemic activities in rat models of diabetes. Following subcutaneous injection in diabetic rats, insulin- and insulin glargine-loaded nanoparticles of diverse morphologies had demonstrated up to 2.6-fold and 1.7-fold increase in pharmacological availability, in comparison to free insulin and insulin glargine, respectively. All together, the negligible cytotoxicity, immunotoxicity, and minimal cytokine adsorption onto nanoparticles (as have been demonstrated in our previous studies) provide exciting and promising evidence of biocompatible nanoconstructs that are poised for further development toward the management of diabetes.

Betaxolol-loaded niosomes integrated within pH-sensitive in situ forming gel for management of glaucoma

Blindness and impaired vision are considered as the most troublesome health conditions leading to significant socioeconomic strains. The current study focuses on development of nanoparticulate systems (i.e., niosomes) as drug vehicles to enhance the ocular availability of betaxolol hydrochloride for management of glaucoma. Betaxolol-loaded niosomes were further laden into pH-responsive in situ forming gels to further extend precorneal retention of the drug. The niosomes were evaluated in terms of vesicle size, morphology, size distribution, surface charge and encapsulation efficiency. The optimized niosomes, comprised of Span® 40 and cholesterol at a molar ratio of 4:1, displayed particle size of 332 ± 7 nm, zeta potential of -46 ± 1 mV, and encapsulation efficiency of 69 ± 5%. The optimal nanodispersion was then incorporated into a pH-triggered in situ forming gel comprised of Carbopol® 934P and hydroxyethyl cellulose. The formed gels were translucent, pseudoplastic, mucoadhesive, and displayed a sustained in vitro drug release pattern. Upon instillation of the betaxolol-loaded niosomal gel into rabbits' eyes, a prolonged intraocular pressure reduction and significant enhancement in the relative bioavailability of betaxolol (280 and 254.7%) in normal and glaucomatous rabbits, were attained compared to the marketed eye drops, respectively. Hence, the developed pH-triggered nanoparticulate gelling system might provide a promising carrier for ophthalmic drug delivery and for improved augmentation of glaucoma.

Engineering of smart nanoconstructs for delivery of glucagon-like peptide-1 analogs

Glucagon-like peptide-1 (GLP-1) receptor agonists are being increasingly exploited in clinical practice for management of type 2 diabetes mellitus due to their ability to lower blood glucose levels and reduce off-target effects of current therapeutics. Nanomaterials had viewed myriad breakthroughs in protecting peptides against degradation and carrying therapeutics to targeted sites for maximizing their pharmacological activity and overcoming limitations associated with their application. This review highlights the latest advances in designing smart multifunctional nanoconstructs and engineering targeted and stimuli-responsive nanoassemblies for delivery of GLP-1 receptor agonists. Furthermore, advanced nanoconstructs of sophisticated supramolecular assembly yet efficient delivery of GLP-1/GLP-1 analogs, nanodevices that mediate intrinsic GLP-1 secretion per se, and nanomaterials with capabilities to load additional moieties for synergistic antidiabetic effects, are demonstrated.

Design and Preclinical Evaluation of Chitosan/Kaolin Nanocomposites with Enhanced Hemostatic Efficiency

In the current study, hemostatic compositions including a combination of chitosan and kaolin have been developed. Chitosan is a marine polysaccharide derived from chitins, a structural component in the shells of crustaceans. Both chitosan and kaolin have the ability to mediate a quick and efficient hemostatic effect following immediate application to injury sites, and thus they have been widely exploited in manufacturing of hemostatic composites. By combining more than one hemostatic agent (i.e., chitosan and kaolin) that act via more than one mechanism, and by utilizing different nanotechnology-based approaches to enhance the surface areas, the capability of the dressing to control bleeding was improved, in terms of amount of blood loss and time to hemostasis. The nanotechnology-based approaches utilized to enhance the effective surface area of the hemostatic agents included the use of Pluronic nanoparticles, and deposition of chitosan micro- and nano-fibers onto the carrier. The developed composites effectively controlled bleeding and significantly improved hemostasis and survival rates in two animal models, rats and rabbits, compared to conventional dressings and QuikClot^® Combat Gauze. The composites were well-tolerated as demonstrated by their in vivo biocompatibility and absence of clinical and biochemical changes in the laboratory animals after application of the dressings.

Nanoparticles integrating natural and synthetic polymers for in vivo insulin delivery

The aims of the current study were to develop insulin-loaded nanoparticles comprised of various polymers at different compositions, and to evaluate their ability to lower blood glucose levels in diabetic rats following subcutaneous and oral administrations. Several combinations of natural and synthetic polymers have been utilized for preparation of nanoparticles including, chitosan, alginate, albumin and Pluronic. Nanosized (170 nm-800 nm) spherical particles of high encapsulation efficiency (15-52%) have been prepared. Composition and ratios between the integrated polymers played a pivotal role in determining size, zeta potential, and in vivo hypoglycemic activity of particles. After subcutaneous and oral administration in diabetic rats, some of the insulin-loaded nanoparticles were able to induce much higher hypoglycemic effect as compared to the unloaded free insulin. For instance, subcutaneous injection of nanoparticles comprised of chitosan combined with sodium tripolyphosphate, Pluronic or alginate/calcium chloride, resulted in comparable hypoglycemic effects to free insulin, at two-fold lower dose. Nanoparticles were well-tolerated after oral administration in rats, as evidenced by by measuring levels of alanine aminotransferase, aspartate aminotransferases, albumin, creatinine and urea. This study indicates that characteristics and delivery efficiency of nanomaterials can be controlled via utilizing several natural/synthetic polymers and by fine-tuning of combination ratio between polymers.

Stability Study and Clinical Evaluation of Lipid Injectable Emulsion in Parenteral Nutrition Admixtures Used for Preterm Neonates

BACKGROUND

Intravenous administration of parenteral nutrition (PN) admixtures containing 4-oil lipid injectable emulsion (ILE) in preterm neonates is usually prohibited because of limited clinical data. The authors evaluated the stability, safety, and efficacy of PN admixtures containing 4-oil ILE, for the first time, in preterm neonates.

METHODS

A series of PN admixtures were prepared for consecutive administration in preterm neonates over a period of 15 days. Admixture stability was assessed after 24 hours of storage at 25 and 37 °C via visual inspection and measurement of mean droplet size (MDS). Safety and efficacy of the admixtures in preterm neonates were assessed via serum triglyceride levels and body weight increase measurements, respectively.

RESULTS

PN admixtures were stable at 25 °C and had MDS ˂500 nm. After 15 days, there was a significant increase in body weight (P ≤ .0001) and level of serum triglycerides (P ≤ .0001), compared with the level before PN administration.

CONCLUSIONS

PN admixtures containing 4-oil ILE were stable at 25 °C and showed instability at 37 °C. Therefore, it is recommended to keep the temperature during administration of PN admixtures at 25 °C. PN admixtures were well tolerated and safe over a period of 8 days while providing a balanced fatty acid supply. Tight monitoring of serum triglyceride level is essential, particularly in neonates of low birth weight and/or young gestational age, to avoid hypertriglyceridemia. Hence, the use of these PN admixtures is expected to be beneficial in terms of being cost-effective and reducing the contamination risks.

Electrospun vancomycin-loaded nanofibers for management of methicillin-resistant Staphylococcus aureus-induced skin infections

Skin damage exposes the underlying layers to bacterial invasion, leading to skin and soft tissue infections. Several pathogens have developed resistance against conventional topical antimicrobial treatments and rendered them less effective. Recently, several nanomedical strategies have emerged as a potential approach to improve therapeutic outcomes of treating bacterial skin infections. In the current study, nanofibers were utilized for topical delivery of the antimicrobial drug vancomycin and evaluated as a promising tool for treatment of topical skin infections. Vancomycin-loaded nanofibers were prepared via electrospinning technique, and vancomycin-loaded nanofibers of the optimal composition exhibited nanosized uniform smooth fibers (ca. 200 nm diameter), high drug entrapment efficiency and sustained drug release patterns over 48 h. In vitro cytotoxicity assays, using several cell lines, revealed the biocompatibility of the drug-loaded nanofibers. In vitro antibacterial studies showed sustained antibacterial activity of the vancomycin-loaded nanofibers against methicillin-resistant Staphylococcus aureus (MRSA), in comparison to the free drug. The nanofibers were then tested in animal model of superficial MRSA skin infection and demonstrated a superior antibacterial efficiency, as compared to animals treated with the free vancomycin solution. Hence, nanofibers might provide an efficient nanodevice to overcome MRSA-induced skin infections and a promising topical delivery vehicle for antimicrobial drugs.

Nanomedicine: a new paradigm to overcome drug incompatibilities

OBJECTIVES

Drug incompatibilities may compromise the safety and effectiveness of combined drugs and result in mild-to-serious clinical complications, such as catheter obstruction, loss of drug efficacy, formation of toxic derivatives and embolism. Various preventive strategies have been implemented to overcome drug incompatibilities with limited success. This review presents an innovative approach to prevent drug incompatibilities via isolating the incompatible drugs into nanostructures.

KEY FINDINGS

Several examples of incompatible drugs may be loaded separately into nanostructures of various types. Physicochemical characteristics and biocompatibility of the nanomaterials that are being utilized to prevent physicochemical incompatibilities should be carefully considered.

CONCLUSIONS

There is a new era of exploiting nanomaterials in overcoming various types of physicochemical incompatibilities, with additional benefits of further improvements in pharmacokinetic profiles and pharmacological actions of the administered drugs.

Toward the Optimization of Dinitrosyl Iron Complexes as Therapeutics for Smooth Muscle Cells

In this study, dinitrosyl iron complexes (DNICs) are shown to deliver nitric oxide (NO) into the cytosol of vascular smooth muscle cells (SMCs), which play a major role in vascular relaxation and contraction. Malfunction of SMCs can lead to hypertension, asthma, and erectile dysfunction, among other disorders. For comparison of the five DNIC derivatives, the following protocols were examined: (a) the Griess assay to detect nitrite (derived from NO conversion) in the absence and presence of SMCs; (b) the 3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4-sulfophenyl)-2 H-tetrazolium (MTS) assay for cell viability; (c) an immunotoxicity assay to establish if DNICs stimulate immune response; and (d) a fluorometric assay to detect intracellular NO from treatment with DNICs. Dimeric Roussin's red ester (RRE)-type {Fe(NO)₂}⁹ complexes containing phenylthiolate bridges, [(μ-SPh)Fe(NO)₂]₂ or SPhRRE, were found to deliver NO with the lowest effect on cell toxicity (i.e., highest IC₅₀). In contrast, the RRE-DNIC with the biocompatible thioglucose moiety, [(μ-SGlu)Fe(NO)₂]₂ (SGlu = 1-thio-β-d-glucose tetraacetate) or SGluRRE, delivered a higher concentration of NO to the cytosol of SMCs with a 10-fold decrease in IC₅₀. Additionally, monomeric DNICs stabilized by a bulky N-heterocyclic carbene (NHC), namely, 1,3-bis(2,4,6-trimethylphenyl)imidazolidene (IMes), were synthesized and yielded the DNIC complexes SGluNHC, [IMes(SGlu)Fe(NO)₂], and SPhNHC, [IMes(SPh)Fe(NO)₂]. These oxidized {Fe(NO)₂}⁹ NHC DNICs have an IC₅₀ of ∼7 μM; however, the NHC-based complexes did not transfer NO into the SMC. Per contra, the reduced, mononuclear {Fe(NO)₂}¹⁰ neocuproine-based DNIC, neoDNIC, depressed the viability of the SMCs, as well as generated an increase of intracellular NO. Regardless of the coordination environment or oxidation state, all DNICs showed a dinitrosyl iron unit (DNIU)-dependent increase in viability. This study demonstrates a structure-function relationship between the DNIU coordination environment and the efficacy of the DNIC treatments.

Absorbable hemostatic hydrogels comprising composites of sacrificial templates and honeycomb-like nanofibrous mats of chitosan

The development of hemostatic technologies that suit a diverse range of emergency scenarios is a critical initiative, and there is an increasing interest in the development of absorbable dressings that can be left in the injury site and degrade to reduce the duration of interventional procedures. In the current study, β-cyclodextrin polyester (CDPE) hydrogels serve as sacrificial macroporous carriers, capable of degradation under physiological conditions. The CDPE template enables the assembly of imprinted chitosan honeycomb-like monolithic mats, containing highly entangled nanofibers with diameters of 9.2 ± 3.7 nm, thereby achieving an increase in the surface area of chitosan to improve hemostatic efficiency. In vivo, chitosan-loaded cyclodextrin (CDPE-Cs) hydrogels yield significantly lower amounts of blood loss and shorter times to hemostasis compared with commercially available absorbable hemostatic dressings, and are highly biocompatible. The designed hydrogels demonstrate promising hemostatic efficiency, as a physiologically-benign approach to mitigating blood loss in tissue-injury scenarios.

Vancomycin-loaded niosomes integrated within pH-sensitive in-situ forming gel for treatment of ocular infections while minimizing drug irritation

Objectives

The aim of the current study was to minimize ocular irritation and prolong the pharmacological action of vancomycin via formulation into nanosized spherical niosomes loaded into pH-sensitive in-situ forming gel.

Methods

Stability and rheological behaviour of the various gelling systems were evaluated. The ability of the selected system to eradicate methicillin-resistant Staphylococcus aureus (MRSA) infections was examined in vitro and in vivo. Draize technique was also used to assess ocular irritation in rabbits.

Key findings

Nanosized spherical niosomes loaded with vancomycin at high entrapment efficiency were prepared and integrated into polymeric solution that forms gel in situ upon instillation into the eye, to allow for a further increase in the ocular residence time. In MRSA-infected rabbits, there were 180- and 2.5-fold increases in the antibacterial efficacy after treatment with the vancomycin niosomal gels in comparison with the untreated animals and the animals treated with the vancomycin free drug solution, respectively.

Conclusions

The developed formulations demonstrated promising in-vivo biocompatibility and antibacterial efficacy, signifying their potential application as ophthalmic preparation to overcome ocular infections induced by resistant bacterial strains while minimizing drug irritation and improving patient compliance.

Functional, Degradable Zwitterionic Polyphosphoesters as Biocompatible Coating Materials for Metal Nanostructures

A zwitterionic polyphosphoester (zPPE), specifically l-cysteine-functionalized poly(but-3-yn-1-yloxy)-2-oxo-1,3,2-dioxaphospholane (zPBYP), has been developed as a poly(ethylene glycol) (PEG) alternative coating material for gold nanoparticles (AuNPs), the most extensively investigated metal nanoparticulate platform toward molecular imaging, photothermal therapy, and drug delivery applications. Thiol-yne conjugation of cysteine transformed an initial azido-terminated and alkynyl-functionalized PBYP homopolymer into zPBYP, offering hydrolytic degradability, biocompatibility, and versatile reactive moieties for installation of a range of functional groups. Despite minor degradation during purification, zPPEs were able to stabilize AuNPs presumably through multivalent interactions between combinations of the side chain zwitterions (thioether and phosphoester groups of the zPPEs with the AuNPs). ³¹P NMR studies in D₂O revealed ca. 20% hydrolysis of the phosphoester moieties of the repeat units had occurred during the workup and purification by aqueous dialysis at pH 3 over ca. 1 d, as observed by the ³¹P signal of the phosphotriesters resonating at ca. -0.5 to -1.7 shifting downfield to ca. 1.1 to -0.4 ppm, attributed to transformation to phosphates. Further hydrolysis of side chain and backbone units proceeded to an extent of ca. 75% over the next 2 d in nanopure water (pH 5-6). The NMR degradation results were consistent with the broadening and red-shift of the surface plasmon resonance (SPR) observed by UV-vis spectroscopy of the zPPE-coated AuNPs in water over time. All AuNP formulations in this study, including those with citrate, PEG, and zPPE coatings, exhibited negligible immunotoxicity, as determined by cytokine overexpression in the presence of the nanostructures relative to those in cell culture medium. Notably, the zPPE-coated AuNPs displayed superior antifouling properties, as assessed by the extent of cytokine adsorption relative to both the PEGylated and citrate-coated AuNPs. Taken together, the physicochemical and biological evaluations of zPPE-coated AuNPs in conjunction with PEGylated and citrate-coated analogues indicate the promise of zPPEs as favorable alternatives to PEG coatings, with negligible immunotoxicity, good antifouling performance, and versatile reactive groups that enable the preparation of highly tailored nanomaterials for diverse applications.

Resistance of primary breast cancer cells with enhanced pluripotency and stem cell activity to sex hormonal stimulation and suppression

Female sex steroid hormones have a fundamental role in breast cancer. Meanwhile, current evidence supports the contribution of breast cancer stem cells in carcinogenesis, metastasis, and resistance to cytotoxic chemotherapy. Nevertheless, the interaction between breast cancer stem cells with sex hormones or key hormonal antagonists remains elusive.

OBJECTIVE

To investigate the effect of diverse sex hormonal stimulation and suppression regimens on the proliferation of a primary human breast cancer cells with stem cell activity.

METHODS

Cells were exposed to estradiol, progesterone, letrozole, ulipristal acetate, or a combination of ulipristal acetate-letrozole, continually for 6 months. Additionally, nanoparticle-linked letrozole and ulipristal acetate formulations were included in a subsequent short-term exposure study. Phenotypic, pathologic, and functional characteristics of unexposed cells were investigated.

RESULTS

The proliferation of breast cancer cells was comparable among all hormonal stimulation and suppression groups (P= 0.8). In addition, the nanoparticle encapsulated hormonal antagonists were not able to overcome the observed resistance of cells. Cell characterization showed a mesenchymal-like phenotype overexpressing three master pluripotency markers (Oct 4, SOX2, and Nanog), and 92% of cells were expressing ALDH1A1. Notably, the CD44 ^high/CD24 ^low cell population presented only 0.97%-5.4% over repeat analyses. Most cells lacked the expression of mesenchymal markers; however, they showed differentiation into osteogenic and adipogenic lineages. Upon transfer to serum-free culture, the long-term maintained mesenchymal-like cancer cells showed remarkable morphologic plasticity as they switched promptly into an epithelial-like phenotype with significant mammosphere formation capacity (P= 0.008).

CONCLUSION

Breast cancer cells can develop a pluripotent program with enhanced stemness activity that may together contribute to universal resistance to sex hormonal stimulation or deprivation. Isolation and characterization of patient-derived breast cancer stem cells in large clinical studies is therefore crucial to identify new targets for endocrine therapies, potentially directed towards stemness and pluripotency markers. Such direction may help overcoming endocrine resistance and draw attention to breast cancer stem cells' behaviour under endogenous and exogenous sex hormones throughout a woman's reproductive life.

Acid-Triggered Polymer Backbone Degradation and Disassembly to Achieve Release of Camptothecin from Functional Polyphosphoramidate Nanoparticles

Camptothecin (CPT) is a promising anticancer drug, yet its therapeutic potential has been limited by poor water solubility and facile hydrolysis of the lactone form into an inactive carboxylate form at neutral pH. In this work, a fundamental synthetic methodology was advanced to allow for the preparation of well-defined functional polyphosphoramidate (PPA)-based block copolymers that coassembled with CPT into nanoparticles, which underwent coincident acid-triggered polymer backbone degradation, nanoparticle disassembly, and CPT release. Encapsulation of CPT by the PPA polymer inhibited premature hydrolysis of CPT at pH 7.4 and enabled accelerated CPT release at pH 5.0 (ca. 4× faster than at pH 7.4). Two degradable oxazaphospholidine monomers, with one carrying an alkyne group, were synthesized to access well-defined block PPAs (dispersity, Đ<1.2) via sequential organobase-catalyzed ring-opening polymerizations (ROP). The resulting amphiphilic block copolymers (PEOMP-b-PBYOMP) were physically loaded with CPT to achieve well-dispersed nanotherapeutics, which allowed the aqueous suspension of CPT at concentrations up to 3.2 mg/mL, significantly exceeding the aqueous solubility of the drug (<2.0 μg/mL at 37 °C). Cytotoxicity studies revealed enhanced efficacy of the CPT-loaded nanoparticles over free CPT in cancer cells and similar toxicity in normal cells.

Development and in vivo evaluation of chitosan nanoparticles for the oral delivery of albumin

Albumin is used as a plasma expander in critically ill patients and for several other clinical applications mainly via intravenous infusion. Oral administration of albumin can improve patient compliance although limited oral bioavailability of proteins is still a major challenge. Although nanomaterials have been extensively utilized for improving oral delivery of proteins, albumin has been utilized only as either a model drug or as a carrier for drug delivery. In the current study, for the first time, chitosan nanoparticles have been developed and extensively optimized to improve oral bioavailability of albumin as a therapeutic protein. Several characterizations have been performed for the albumin-loaded nanoparticles (e.g. drug encapsulation efficiency, DSC, FTIR, particle size, zeta potential, morphology, release kinetics, and enzymatic stability). Nanosized spherical particles were prepared and demonstrated high stability over three months either in a powdered form or as suspensions. Sustained release of albumin over time and high enzymatic stability as compared to the free albumin were observed. In vivo, higher serum concentrations of albumin in normal rabbits and cirrhotic rats were attained following oral and intraperitoneal administrations of the albumin-loaded nanoparticles as compared to the free albumin. The nanoparticles developed in the current study might provide efficient nanovehicles for oral administration of therapeutic albumin.

A Vinyl Ether-Functional Polycarbonate as a Template for Multiple Postpolymerization Modifications

A highly-reactive vinyl ether-functionalized aliphatic polycarbonate and its block copolymer were developed as templates for multiple post-polymerization conjugation chemistries. The vinyl ether-functional six-membered cyclic carbonate monomer was synthesized by a well-established two-step procedure starting from 2,2-bis(hydroxymethyl)propionic acid. An organobase-catalyzed ring-opening polymerization of the synthesized monomer afforded polycarbonates with pendant vinyl ether functionalities (PMVEC). The vinyl ether moieties on the resulting polymers were readily conjugated with hydroxyl- or thiol-containing compounds via three different post-polymerization modification chemistries - acetalization, thio-acetalization, and thiol-ene reaction. Acetal-functionalized polycarbonates were studied in depth to exploit their acid-labile acetal functionalities. Acetalization of the amphiphilic diblock copolymer of poly(ethylene glycol) methyl ether (mPEG) and PMVEC, mPEG113-b-PMVEC13, with the model hydroxyl compound 4- methylbenzyl alcohol resulted in a maximum of 42% acetal and 58% hydroxyl side chain groups. Nonetheless, the amphiphilicity of the block polymer allowed for its self-assembly in water to afford nanostructures, as characterized via dynamic light scattering and transmission electron microscopy. The kinetics of acetal cleavage within the block polymer micelles were examined in acidic buffered solutions (pH 4 and 5). In addition, mPEG-b-PMVEC and its hydrolyzed polymer mPEG-b-PMHEC (i.e., after full cleavage of acetals) exhibited minimal cytotoxicity to RAW 264.7 mouse macrophages, indicating that this polymer system represents a biologically non-hazardous material with pH-responsive activity.

Development of Fully Degradable Phosphonium-Functionalized Amphiphilic Diblock Copolymers for Nucleic Acids Delivery

To expand the range of functional polymer materials to include fully hydrolytically degradable systems that bear bioinspired phosphorus-containing linkages both along the backbone and as cationic side chain moieties for packaging and delivery of nucleic acids, phosphonium-functionalized polyphosphoester- block-poly(l-lactide) copolymers of various compositions were synthesized, fully characterized, and their self-assembly into nanoparticles were studied. First, an alkyne-functionalized polyphosphoester- block-poly(l-lactide) copolymer was synthesized via a one pot sequential ring opening polymerization of an alkyne-functionalized phospholane monomer, followed by the addition of l-lactide to grow the second block. Second, the alkynyl side groups of the polyphosphoester block were functionalized via photoinitiated thiol-yne radical addition of a phosphonium-functionalized free thiol. The polymers of varying phosphonium substitution degrees were self-assembled in aqueous buffers to afford formation of well-defined core-shell assemblies with an average size ranging between 30 and 50 nm, as determined by dynamic light scattering. Intracellular delivery of the nanoparticles and their effects on cell viability and capability at enhancing transfection efficiency of nucleic acids (e.g., siRNA) were investigated. Cell viability assays demonstrated limited toxicity of the assembly to RAW 264.7 mouse macrophages, except at high polymer concentrations, where the polymer of high degree of phosphonium functionalization induced relatively higher cytotoxicity. Transfection efficiency was strongly affected by the phosphonium-to-phosphate (P+/P-) ratios of the polymers and siRNA, respectively. The AllStars Hs Cell Death siRNA complexed to the various copolymers at a P+/P- ratio of 10:1 induced comparable cell death to Lipofectamine. These fully degradable nanoparticles might provide biocompatible nanocarriers for therapeutic nucleic acid delivery.

Design and development of multifunctional polyphosphoester-based nanoparticles for ultrahigh paclitaxel dual loading

Multifunctional polyphosphoester-based nanoparticles capable of loading paclitaxel (PTX) both chemically and physically were prepared, achieving an ultrahigh equivalent PTX aqueous concentration of 25.30 mg mL^-1. The dual-loaded nanoparticles were effective in killing cancer cells, which has the potential to minimize the amount of nanocarriers needed for clinical applications, due to their ultrahigh loading capacity.