A review of drug delivery systems based on nanotechnology and green chemistry: green nanomedicine

Biocompatible PEO-b-PCL Nanosized Micelles as Drug Carriers: Structure and Drug-Polymer Interactions

We report on the preparation of drug nanocarriers by encapsulating losartan potassium (LSR) into amphiphilic block copolymer micelles, utilizing the biocompatible/biodegradable poly(ethylene oxide)-b-poly(ε-caprolactone) (PEO-b-PCL) diblock copolymer. The PEO-b-PCL micelles and LSR-loaded PEO-b-PCL nanocarriers were prepared by organic solvent evaporation method (OSEM). Light scattering and nuclear magnetic resonance (NMR) provide information on micelle structure and polymer-drug interactions. According to dynamic light scattering (DLS) analysis, the PEO-b-PCL micelles and LSR-loaded PEO-b-PCL nanocarriers formed nanostructures in the range of 17-26 nm in aqueous milieu. Attenuated total reflection Fourier transform infrared (ATR-FTIR) and ultraviolet-visible (UV-Vis) measurements confirmed the presence of LSR in the polymeric drug solutions. NMR results proved the successful encapsulation of LSR into the PEO-b-PCL micelles by analyzing the drug-micelles intermolecular interactions. Specifically, 2D-NOESY experiments clearly evidenced the intermolecular interactions between the biphenyl ring and butyl chain of LSR structure with the methylene signals of PCL. Additionally, NMR studies as a function of temperature demonstrated an unexpected, enhanced proton mobility of the PEO-b-PCL micellar core in D₂O solutions, probably caused by the melting of the PCL hydrophobic core.

Novel Nanotherapeutics as Next-generation Anti-infective Agents: Current Trends and Future Prospectives

With the ever-increasing population and improvement in the healthcare system in the 21st century, the incidence of chronic microbial infections and associated health disorders has also increased at a striking pace. The ability of pathogenic microorganisms to form biofilm matrix aggravates the situation due to antibiotic resistance phenomenon resulting in resistance against conventional antibiotic therapy which has become a public health concern. The canonical Quorum Sensing (QS) signaling system hierarchically regulates the expression of an array of virulence phenotypes and controls the development of biofilm dynamics. It is imperative to develop an alternative, yet effective and non-conventional therapeutic approach, popularly known as "anti-infective therapy" which seems to be interesting. In this regard, targeting microbial QS associated virulence and biofilm development proves to be a quite astonishing approach in counteracting the paucity of traditional antibiotics. A number of synthetic and natural compounds are exploited for their efficacy in combating QS associated microbial infections but the bioavailability and biocompatibility limit their widespread applications. In this context, the nanotechnological intervention offers a new paradigm for widespread biomedical applications starting from targeted drug delivery to diagnostics for the diagnosis and treatment of infectious diseases, particularly to fight against microbial infections and antibiotics resistance in biofilms. A wide range of nanomaterials ranging from metallic nanoparticles to polymeric nanoparticles and recent advances in the development of carbon-based nanomaterials such as Carbon Nanotubes (CNTs), Graphene Oxide (GO) also immensely exhibited intrinsic antiinfective properties when targeted towards microbial infections and associated MDR phenomenon. In addition, the use of nano-based platforms as carriers emphatically increases the efficacy of targeted and sitespecific delivery of potential drug candidates for preventing microbial infections.

Liquid-phase exfoliation of black sesame to create a nanoplatform for in vitro photoluminescence and photothermal therapy

Aim: The present study aims to apply the facile liquid-phase exfoliation (LPE) strategy to fabricate 2D organic materials and thus to broaden the family of biocompatible and multifunctional 2D materials. Materials & methods: 2D material-organic melanin and cellulose nanosheets were synthesized from black sesame hull using LPE. Photoluminescence and photothermal properties of the nanosheets were assessed, as well as stability and cell killing ability. Results: The prepared 2D nanoplatform exhibited broad and multiple photoluminescent emission bands. It also demonstrated efficient photothermal cancer therapy with excellent biocompatibility. Conclusion: The present study could open an avenue in exfoliating organic materials using the LPE strategy. This could make the fabrication of multifunctional 2D organic materials more efficient and broaden the family of biocompatible 2D nanomaterials.

Therapeutic Advancements in the Management of Diabetes Mellitus with Special Reference to Nanotechnology

For improvisation of diabetic's quality of life, nanotechnology is facilitating the development of advanced glucose sensors as well as efficient insulin delivery systems. Our prime focus of the review is to highlight the advancement in diabetic research with special reference to nanotechnology at its interface. Recent studies are more focused on enhancing sensitivity, accuracy, and response by employing metal as well as nanoparticles based glucose sensors. Moreover, the review focuses on nanoscale based approaches i.e. closed-loop insulin delivery systems, which detect any fluctuation in blood glucose levels and allow controlled release of a drug, thus are also called self-regulating insulin release system. Additionally, this review summarizes the role of nanotechnology in the diagnosis and treatment of diabetic complications through little advancement in the existing techniques. To improve health, as well as the quality of life in diabetic's new sensing systems for blood glucose level evaluation and controlled administration of drugs through efficient drug delivery systems should be explored.

Changing the Vision in Smart Food Design Utilizing the Next Generation of Nanometric Delivery Systems for Bioactive Compounds

In modern foods, the delivery systems for bioactive compounds play a fundamental role in health promotion, wellbeing, and disease prevention through diet. Nanotechnology has secured a fundamental role in the fabrication of delivery systems with the capability of modulating the in-product and in-body behavior for augmenting bioavailability and activity of bioactive compounds. Structured nanoemulsions and nanoparticles, liposomes, and niosomes can be designed to improve bioactives preservation after ingestion, mucoadhesion, as well as of their release and pathophysiological relevance. In the future, it is expected that the delivery systems will also contribute to augment the efficacy of the bioactive compounds, for example by improving the intestinal absorption and delivery in the bloodstream, as well as promoting the formation of additional bioactive metabolites by regulating the transformations taking place during digestion and the interaction with the intestinal microbiota.

Nanoparticles and Colloidal Hydrogels of Chitosan-Caseinate Polyelectrolyte Complexes for Drug-Controlled Release Applications

Chitosan–caseinate nanoparticles were synthesized by polyelectrolyte complex (PEC) formation. Caseinate is an anionic micellar nanocolloid in aqueous solutions, which association with the polycationic chitosan yielded polyelectrolyte complexes with caseinate cores surrounded by a chitosan corona. The pre-structuration of caseinate micelles facilitates the formation of natural polyelectrolyte nanoparticles with good stability and sizes around 200 nm. Such natural nanoparticles can be loaded with molecules for applications in drug-controlled release. In the nanoparticles processing, parameters such as the chitosan degree of acetylation (DA) and molecular weight, order of addition of the polyelectrolytes chitosan (polycation) and caseinate (polyanion), and added weight ratio of polycation:polyanion were varied, which were shown to influence the structure of the polyelectrolyte association, the nanoparticle size and zeta potential. Attenuated total reflection-Fourier transform infrared (ATR-FTIR) analyses revealed the chemical structure of hydrogel colloidal systems consisting of nanoparticles that contain chitosan and caseinate. Transmission electron microscopy (TEM) allowed further characterization of the spherical morphology of the nanoparticles. Furtherly, insulin was chosen as a model drug to study the application of the nanoparticles as a safe biodegradable nanocarrier system for drug-controlled release. An insulin entrapment efficiency of 75% was achieved in the chitosan-caseinate nanoparticles.

Polyphenols as Potential Agents in the Management of Temporomandibular Disorders

Temporomandibular disorders (TMD) consist of multifactorial musculoskeletal disorders associated with the muscles of mastication, temporomandibular joint (TMJ), and annexed structures. This clinical condition is characterized by temporomandibular pain, restricted mandibular movement, and TMJ synovial inflammation, resulting in reduced quality of life of affected people. Commonly, TMD management aims to reduce pain and inflammation by using pharmacologic therapies that show efficacy in pain relief but their long-term use is frequently associated with adverse effects. For this reason, the use of natural compounds as an effective alternative to conventional drugs appears extremely interesting. Indeed, polyphenols could represent a potential therapeutic strategy, related to their ability to modulate the inflammatory responses involved in TMD. The present work reviews the mechanisms underlying inflammation-related TMD, highlighting the potential role of polyphenols as a promising approach to develop innovative management of temporomandibular diseases.

Improving the Functional Activities of Curcumin Using Milk Proteins as Nanocarriers

Curcumin is one of the most common spices worldwide. It has potential benefits, but its poor solubility and bioavailability have restricted its application. To overcome these problems, this study aimed to assess the efficacy of sodium caseinate (SC), α-lactalbumin (α-La), β-lactoglobulin (β-lg), whey protein concentrate (WPC) and whey protein isolate (WPI) as nanocarriers of curcumin. Furthermore, the antioxidant, anticancer and antimicrobial activities of the formed nanoparticles were examined. The physicochemical characteristics of the formed nanoparticles as well as the entrapment efficiency (%) and the in vitro behavior regarding the release of curcumin (%) were examined. The results showed that the formation of curcumin–milk protein nanoparticles enhanced both the entrapment efficiency and the in vitro behavior release of curcumin (%). Cur/β-lg nanoparticles had the highest antioxidant activity, while SC and WPC nanoparticles had the highest anticancer effect. The antimicrobial activity of the formed nanoparticles was much higher compared to curcumin and the native milk proteins.

Prospects on Nano-Based Platforms for Antimicrobial Photodynamic Therapy Against Oral Biofilms

Objective: This review clusters the growing field of nano-based platforms for antimicrobial photodynamic therapy (aPDT) targeting pathogenic oral biofilms and increase interactions between dental researchers and investigators in many related fields. Background data: Clinically relevant disinfection of dental tissues is difficult to achieve with aPDT alone. It has been found that limited penetrability into soft and hard dental tissues, diffusion of the photosensitizers, and the small light absorption coefficient are contributing factors. As a result, the effectiveness of aPDT is reduced in vivo applications. To overcome limitations, nanotechnology has been implied to enhance the penetration and delivery of photosensitizers to target microorganisms and increase the bactericidal effect. Materials and methods: The current literature was screened for the various platforms composed of photosensitizers functionalized with nanoparticles and their enhanced performance against oral pathogenic biofilms. Results: The evidence-based findings from the up-to-date literature were promising to control the onset and the progression of dental biofilm-triggered diseases such as dental caries, endodontic infections, and periodontal diseases. The antimicrobial effects of aPDT with nano-based platforms on oral bacterial disinfection will help to advance the design of combination strategies that increase the rate of complete and durable clinical response in oral infections. Conclusions: There is enthusiasm about the potential of nano-based platforms to treat currently out of the reach pathogenic oral biofilms. Much of the potential exists because these nano-based platforms use unique mechanisms of action that allow us to overcome the challenging of intra-oral and hard-tissue disinfection.

Carbohydrate-Based Micro/Nanocapsules With Controlled External Surface for Medical Applications

Micro/nanocapsules would have many more applications if we were able to controllably populate their surface with various chemical moieties. The present review introduces a novel variant of interfacial polymerization (IP) as a very robust method of manufacturing reservoir micro/nanocapsules equipped with several different functionalities on the capsules' surface. We call the method—IPCESCO (Interfacial Polymerization for Capsules' External Surface Control). As always in IP, the capsules' forming reaction is between monomers dissolved in opposite phases (oil or water) and takes place at the interface. Each monomer carries two or more functionalities reacting with functional groups of the monomer dissolved in the other phase. IPCESCO requires that one or both monomers are additionally equipped with (protected) functional groups interfering neither with the payload nor with the polymer formation. These additional groups end up everywhere in the polymeric shell but most importantly they are present on the external surface of capsules. These “handles” allow for the introduction of various moieties onto the capsules' surface. Since carbohydrate chemists developed a plurality of protecting and deprotecting methods for various functional groups such as aldehyde and hydroxyl, modified mono, and oligosaccharides are particularly well-suited to act as monomers in IPCESCO. The article discusses possible monomers and their synthesis, the transformation of protected reactive groups on the external capsules' surface into the desired functionalities, the control of the number of moieties on the surface and the capsules surface's architecture. The most important application of the novel encapsulation technology is in drug delivery. Possible surface units facilitating capsules' transport in the body, delivery to specific locations and mechanisms of capsules rupture are also addressed. Other applications of novel capsules include an ultra-sensitive quantitation and removal of pathogens, transport of nutrients in plants, detection of various antigens and other parameters in single cells.

Gold Nanoparticles Perturb Drug-Metabolizing Enzymes and Antioxidants in the Livers of Male Rats: Potential Impact on Drug Interactions

Background and Aim

With the wide applications of chitosan and gold nanoparticles in drug delivery and many consumer products, there is limited available information about their effects on drug-metabolizing enzymes (DMEs). Changes in DMEs could result in serious drug interactions. Therefore, this study aimed to investigate the effects of exposure to chitosan or gold nanoparticles on hepatic Phase I and II DMEs, liver function and integrity, oxidative damage and liver architecture in male rats.

Methods

Animals were divided into three equal groups: a control group, a group treated with chitosan nanoparticles (200 mg/kg, 50±5 nm) and a group treated with gold nanoparticles (4 mg/kg, 15±5 nm). Rats were orally administered their respective doses daily for 10 days.

Results

Both chitosan and gold nanoparticles decreased the body weights by more than 10%. Gold nanoparticles reduced the activities of antioxidants (superoxide dismutase and catalase), and reduced glutathione level and elevated the malondialdehyde level in the liver. Gold nanoparticles caused significant reductions in CYP1A1, CYP2E1, quinone oxidoreductase1, and glutathione S-transferase and elevated CYP2D6 and N-acetyl transferase2. Chitosan elevated CYP2E1 and CYP2D6 and reduced UDP-glucuronosyltransferase 1A1. Both nanoparticles disturbed the architecture of the liver, but the deleterious effects after gold nanoparticles treatment were more prominent.

Conclusion

Taken together, gold nanoparticles severely perturbed the DMEs and would result in serious interactions with many drugs, herbs, and foods.

Natural products action on pathogenic cues in autoimmunity: Efficacy in systemic lupus erythematosus and rheumatoid arthritis as compared to classical treatments

Systemic lupus erythematosus (SLE) and rheumatoid arthritis (RA), which are characterized by self-perpetuating inflammation and tissue/organ damage, resulting from the failure of lymphocyte auto-tolerance, cause morbidity and mortality worldwide. The current drugs or therapies including conventional non-steroidal anti-inflammatory drugs (NSAIDs) and disease-modifying anti-rheumatic drugs (DMARDs), as well as several biologic therapies such as B cell-targeted, T cell-targeted, cytokines-targeted and cytokines receptors-targeted therapy, cannot completely cure SLE and RA, and are always accompanied by unexpected side effects. Therefore, more studies have explored new methods for therapy and found that the herbal medicine as well as its natural products (NPs) exhibited promising therapeutic value through exerting effects of immunomodulation, anti-inflammation, anti-oxidation, and anti-apoptosis, etc. via regulating abnormal responses in kidney, innate and adaptive immune systems, intestine, synoviocytes, as well as bone system including chondrocytes, osteoclasts, joints and paw tissues. In the present review, we will elucidate the current mainstream drugs and therapies for SLE and RA, and summarize the efficacy and mechanisms of NPs in the treatment of SLE and RA based on available findings including in vitro and in vivo animal models, as well as clinical studies, and further analyze the existing challenges, in order to provide comprehensive evidence for improvement of SLE and RA therapy by NPs and to promote management of these two autoimmune diseases.

Casein nanoparticles as oral delivery carriers of mequindox for the improved bioavailability

Mequindox (Meq) is a promising broad-spectrum antibacterial agent, but the clinical application of Meq has been hampered by its low oral bioavailability. Casein (Cas) can bind to a variety of poorly water-soluble drugs to improve their water solubility through a micellar solubilization mechanism. Here, a low-cost and convenient method was introduced to prepare mequindox-loaded casein nanoparticles (Meq-Cas). Meq-Cas was characterized by several methods including differential scanning calorimetry (DSC), X-ray diffraction (XRD), and fourier transform infrared (FTIR) to illuminate the mutual effect between the drug and carriers. Meq-Cas presented nearly spherical nanoparticles with smooth surfaces and its mean particle size was lower than untreated Cas. Meq-Cas showed a nearly complete release of Meq, which displayed a biphasic drug release pattern in both phosphate-buffered solution (PBS) and simulated gastric fluid (SGF). The relative oral bioavailability of Meq-Cas was found to be about 1.20 times higher than that of the animals treated with Meq suspension (control). These results suggest that Cas is a good candidate to load in Meq for pharmaceutical purposes.

Understanding the self-assembly pathways of a single chain variant of monellin: A first step towards the design of sweet nanomaterials

Peptides and proteins possess an inherent tendency to self-assemble, prompting the formation of amyloid aggregates from their soluble and functional states. Amyloids are linked to many devastating diseases, but self-assembling proteins can also represent formidable tools to produce new and sustainable biomaterials for biomedical and biotechnological applications. The mechanism of fibrillar aggregation, which influences the morphology and the properties of the protein aggregates, depend on factors such as pH, ionic strength, temperature, agitation, and protein concentration. We have here used intensive mechanical agitation, with or without beads, to prompt the aggregation of the single-chain derivative of the plant protein monellin, named MNEI, which is a well characterized sweet protein. Transmission electron microscopy confirmed the formation of fibrils several micrometers long, morphologically different from the previously characterized fibers of MNEI. Changes in the protein secondary structures during the aggregation process were monitored by Fourier transform infrared spectroscopy, which detected differences in the conformation of the final aggregates obtained under mechanical agitation. Moreover, soluble oligomers could be detected in the early phases of aggregation by polyacrylamide gel-electrophoresis. These findings emphasize the existence of multiple pathways of fibrillar aggregation for MNEI, which could be exploited for the design of innovative protein-based biomaterials.

Membrane-core nanoparticles for cancer nanomedicine

Cancer is one of the most severe disease burdens in modern times, with an estimated increase in the number of patients diagnosed globally from 18.1 million in 2018 to 23.6 million in 2030. Despite a significant progress achieved by conventional therapies, they have limitations and are still far from ideal. Therefore, safe, effective and widely-applicable treatments are urgently needed. Over the past decades, the development of novel delivery approaches based on membrane-core (MC) nanostructures for transporting chemotherapeutics, nucleic acids and immunomodulators has significantly improved anticancer efficacy and reduced side effects. In this review, the formulation strategies based on MC nanostructures for delivery of anticancer drug are described, and recent advances in the application of MC nanoformulations to overcome the delivery hurdles for clinical translation are discussed.

Stimulus-responsive tea polyphenols as nanocarrier for selective intracellular drug delivery

Nanodrug delivery systems have been widely researched to achieve efficient antitumor drug delivery. However, the controlled drug delivery at tumor cells remains the main challenge for antitumor therapy. Herein, a pH and reduction-responsive nanocarrier based on green tea polyphenols was employed as a smart excipient for chemotherapy drug delivery. Paclitaxel, as a chemotherapy drug, was loaded in the nanocarrier, noted as green tea polyphenol/paclitaxel. The green tea polyphenol/paclitaxel kept constant diameter at physiological condition (i.e. pH 7.4), while gradually enlarged at acid environment (pH = 5.5) and the reductive environment. The in vitro paclitaxel release results indicated that the release of paclitaxel from the green tea polyphenol/paclitaxel at pH 7.4 was slow, whereas obviously accelerated at the acid environment (pH = 5.5) and the reductive environment. The in vitro antitumor assay showed more efficient tumor cells inhibition of green tea polyphenol/paclitaxel than free paclitaxel. Meanwhile, due to the proper size (∼100 nm), green tea polyphenol/paclitaxel could effectively accumulate at tumor sites. In the in vivo mice bearing A549 xenograft mouse models, green tea polyphenol/paclitaxel exhibited satisfactory antitumor effect and depressed system toxicity when compared with free paclitaxel, owing to the enhanced paclitaxel accumulation and controlled paclitaxel release in the tumor cells. With simple compositions and satisfactory antitumor effects, this green tea polyphenol-based nanocarrier can be a promising nanodrug delivery system for the therapy of cancers.

Naturally derived DNA nanogels as pH- and glutathione-triggered anticancer drug carriers

Conventional chemotherapeutic drugs are nonselective and harmful toward normal tissues, causing severe side effects. Therefore, the development of chemotherapeutics that can target cancer cells and improve therapeutic efficacy is of high priority. Biomolecules isolated from nature serve as green solutions for biomedical use, solving biocompatibility and cytotoxicity issues in human bodies. Herein, we use kiwifruit-derived DNA to encapsulate doxorubicin (DOX) using crosslinkers, eventually forming DNA-DOX nanogels (NGs). Drug releasing assays, cell viability and anticancer effects were analyzed to evaluate the DNA NGs' applications. The amount of DOX released by the DOX-loaded DNA (DNA-DOX) NGs at acidic pH was higher than that of neutral pH, and high glutathione (GSH) concentration also triggered more DOX to release in cancer cells, demonstrating pH- and GSH-triggered drug release characteristics of the DNA NGs. The IC₅₀ of DNA-DOX NGs in cancer cells was lower than that of free DOX. Moreover, DOX uptake of cancer cells and apoptotic death were enhanced by the DNA-DOX NGs compared to free DOX. The results suggest that the DNA NGs cross-linked via nitrogen bases of the nucleotides in DNA and presenting pH- and GSH-dependent drug releasing behavior can be alternative biocompatible drug delivery systems for anticancer strategies and other biomedical applications.

Novel self-nanomicellizing formulation based on Rebaudioside A: A potential nanoplatform for oral delivery of naringenin

In the study described here, we strove to develop an orally administered novel self-nanomicellizing formulation based on Rebaudioside A (RA) for delivering naringenin (NAR) with improved bioavailability and therapeutic efficacy. Our research found that RA and naringenin (NAR) could be formulated into self-assembling nanomicelles (RA-NAR) using a simple ethanol dissolution-evaporation method. We found that the RA-NAR self-assemblies comprised ultra-small micelles (5.234 ± 0.311 nm) in a uniform dispersion state (the polydispersity index was 0.243 ± 0.039) with a near-neutral surface charge (-[2.268 ± 0.729] mV). We also found that RA-NAR had a well-storage stability at 4 °C with light protection. In addition, we observed that RA-NAR exhibited enhanced apparent solubility, in-vitro permeability, and antioxidant activity. After we administered RA-NAR to rats orally, we observed an increase in area under the curve (AUC_0→t) to 19,500.82 ng/mL/h versus 9324.47 ng/mL/h observed with free NAR and an increase of maximum concentration (Cmax) to 27,326.10 ng/mL from the free-NAR Cmax level of 2549.04 ng/mL. The tissue distribution assessments further demonstrated that RA-NAR could effectively increase the NAR concentration in all tested intestinal segments. Our mouse model results showed as well that oral administration of RA-NAR could efficiently protect against small intestine injuries induced by indomethacin, and the mechanisms by inhibiting proinflammatory cytokines and oxidative stress were involved in its therapeutic effect. Taken together, these findings indicate that a self-nanomicellizing formulation based on RA has great potential as a novel oral nano-drug delivery system for NAR.

Cytotoxic and apoptotic properties of a novel nano-toxin formulation based on biologically synthesized silver nanoparticle loaded with recombinant truncated pseudomonas exotoxin A

Bacterial toxins have received a great deal of attention in the development of antitumor agents. Currently, these protein toxins were used in the immunotoxins as a cancer therapy strategy. Despite the successful use of immunotoxins, immunotherapy strategies are still expensive and limited to hematologic malignancies. In the current study, for the first time, a nano-toxin comprised of truncated pseudomonas exotoxin (PE38) loaded silver nanoparticles (AgNPs) were prepared and their cytotoxicity effect was investigated on human breast cancer cells. The PE38 protein was cloned into pET28a and expressed in Escherichia coli, BL21 (DE3), and purified using metal affinity chromatography and was analyzed by 15% sodium dodecyl sulfate-polyacrylamide gel electrophoresis. AgNPs were biologically prepared using cell-free supernatant of E. Coli K12 strain. Nanoparticle formation was characterized by energy dispersive spectroscopy, transmission electron microscopy, and dynamic light scattering. The PE38 protein was loaded on AgNPs and prepared the PE38-AgNPs nano-toxin. Additionally, in vitro release indicated a partial slow release of toxin in about 100 hr. The nano-toxin exhibited dose-dependent cytotoxicity on MCF-7 cells. Also, real-time polymerase chain reaction results demonstrated the ability of nano-toxin to upregulate Bax/Bcl-2 ratio and caspase-3, -8, -9, and P53 apoptotic genes in the MCF-7 tumor cells. Apoptosis induction was determined by Annexin-V/propidium flow cytometry and caspases activity assay after treatment of cancer cells with the nano-toxin. In general, in the current study, the nano-toxin exhibit an inhibitory effect on the viability of breast cancer cells through apoptosis, which suggests that AgNPs could be used as a delivery system for targeting of toxins to cancer cells.

Approaches for CNS delivery of drugs - nose to brain targeting of antiretroviral agents as a potential attempt for complete elimination of major reservoir site of HIV to aid AIDS treatment

INTRODUCTION

Human immune-deficiency virus (HIV) infection causing acquired immune-deficiency syndrome (AIDS) is one of the most life-threatening infections. The central nervous system (CNS) is reported to be the most important HIV reservoir site where the antiretroviral drugs are unable to reach.

AREAS COVERED

This article includes the review about HIV infections, its pathogenesis, HIV infections in CNS, its consequences, current therapies, challenges associated with the existing therapies, approaches to overcome them, CNS delivery of drugs - barriers, transport routes, approaches for transporting drugs across the blood-brain barrier, nasal route of drug delivery, and nose to brain targeting of antiretroviral agents as a potential approach for complete cure of AIDS.

EXPERT OPINION

Various approaches are exploited to enhance the drug delivery to the brain for various categories of drugs. However, very few have investigated on the delivery of antiretrovirals to the brain. Targeting antiretrovirals to CNS through oral/nasal routes along with oral/parenteral delivery of drug to the plasma can be a promising approach for an attempt to completely eradicate HIV reservoir and cure AIDS, after clinical trials. Further research is required to identify the exact location of the HIV reservoir in CNS and developing good animal models for evaluation of different newly developed formulations.

Machine-Learning Methods for Computational Science and Engineering

The re-kindled fascination in machine learning (ML), observed over the last few decades, has also percolated into natural sciences and engineering. ML algorithms are now used in scientific computing, as well as in data-mining and processing. In this paper, we provide a review of the state-of-the-art in ML for computational science and engineering. We discuss ways of using ML to speed up or improve the quality of simulation techniques such as computational fluid dynamics, molecular dynamics, and structural analysis. We explore the ability of ML to produce computationally efficient surrogate models of physical applications that circumvent the need for the more expensive simulation techniques entirely. We also discuss how ML can be used to process large amounts of data, using as examples many different scientific fields, such as engineering, medicine, astronomy and computing. Finally, we review how ML has been used to create more realistic and responsive virtual reality applications.

Magnetic Hybrid Wax Nanocomposites as Externally Controlled Theranostic Vehicles: High MRI Enhancement and Synergistic Magnetically Assisted Thermo/Chemo Therapy

To fight against cancer, smarter drugs and drug delivery systems are required both to boost the efficiency of current treatments while reducing deleterious side effects, and combine diagnosis/monitoring with therapy (theranosis) in the search for the final goal of personalized medicine. This work presents the design, preparation, and proof-of-principle validation of a novel hybrid organic-inorganic nanocomposite joining together non-invasive imaging capabilities through magnetic resonance imaging and externally actuated therapeutic properties through a combination of chemo- and thermotherapy. The lipidic matrix of the nanocomposite was composed of carnauba wax, which was simultaneously dual loaded with magnetite nanoparticles and the anticancer drug Oncocalyxone A. Obtained formulations were fully characterized and showed outstanding performances as T₂ -contrast agents in magnetic resonance imaging (r₂ >800 mm^-1  s^-1 ), heat generating sources in magnetic hyperthermia (specific absorption rate, SAR>200 W g^-1 _Fe ), and magnetically responsive drug delivery vehicles. The potential of the designed formulations as theranostic agents was validated in vitro and results indicated a synergistic thermo/chemotherapeutic effect derived from heat generation and controlled drug delivery to cancer growth. Thereby, this external control over the drug delivery profile and the integrated imaging capability open the door to personalized cancer medicine and real-time monitoring of tumor progression.

A pH-sensitive delivery system based on N-succinyl chitosan-ZnO nanoparticles for improving antibacterial and anticancer activities of curcumin

Inherent selective cytotoxicity, antibacterial activity and unique physicochemical properties of ZnO nanostructures and chitosan (CS) make them promising candidates for drug delivery. In this study, ZnO nanoparticles functionalized by N-succinyl chitosan as a pH-sensitive delivery system were synthesized to enhance the therapeutic potential of curcumin (CUR). CS coated-ZnO nanoparticles were synthesized by a co-precipitation method in the presence of CS. Chemical modification of CS-ZnO particles was performed by succinic anhydride for introducing -COOH functional groups which were then activated using 1,1'‑carbonyldiimidazole for CUR conjugation. The spherical-like CUR-conjugated system (CUR-CS-ZnO) with the average particle size of 40 nm presented significantly enhanced water dispersibility versus free CUR. The experimental study of CUR release from the system showed a pH-sensitive release profile, which enabled drug delivery to tumors and infection sites. MTT and Annexin-V FITC/PI assays revealed the superior anticancer activity of CUR-CS-ZnO compared to free CUR against breast cancer cells (MDA-MB-231) by inducing the apoptotic response with no cytotoxic effects on HEK293 normal cells. Moreover, CUR conjugation to the system notably dropped the MIC (25 to 50-fold) and MBC values (10 to 40-fold) against S. aureus and E. coli. The features qualify the formulation for anticancer and antimicrobial applications in the future.

Sterically Stabilised Polymeric Mesoporous Silica Nanoparticles Improve Doxorubicin Efficiency: Tailored Cancer Therapy

The fruition, commercialisation and clinical application combining nano-engineering, nanomedicine and material science for utilisation in drug delivery is becoming a reality. The successful integration of nanomaterial in nanotherapeutics requires their critical development to ensure physiological and biological compatibility. Mesoporous silica nanoparticles (MSNs) are attractive nanocarriers due to their biodegradable, biocompatible, and relative malleable porous frameworks that can be functionalized for enhanced targeting and delivery in a variety of disease models. The optimal formulation of an MSN with polyethylene glycol (2% and 5%) and chitosan was undertaken, to produce sterically stabilized, hydrophilic MSNs, capable of efficient loading and delivery of the hydrophobic anti-neoplastic drug, doxorubicin (DOX). The pH-sensitive release kinetics of DOX, together with the anticancer, apoptosis and cell-cycle activities of DOX-loaded MSNs in selected cancer cell lines were evaluated. MSNs of 36-60 nm in size, with a pore diameter of 9.8 nm, and a cumulative surface area of 710.36 m²/g were produced. The 2% pegylated MSN formulation (PCMSN) had the highest DOX loading capacity (0.98 mgdox/mgmsn), and a sustained release profile over 72 h. Pegylated-drug nanoconjugates were effective at a concentration range between 20-50 μg/mL, inducing apoptosis in cancer cells, and affirming their potential as effective drug delivery vehicles.

Recent Developments in the Facile Bio-Synthesis of Gold Nanoparticles (AuNPs) and Their Biomedical Applications

Gold nanoparticles (AuNPs) are extensively studied nanoparticles (NPs) and are known to have profound applications in medicine. There are various methods to synthesize AuNPs which are generally categorized into two main types: chemical and physical synthesis. Continuous efforts have been devoted to search for other more environmental-friendly and economical large-scale methods, such as environmentally friendly biological methods known as green synthesis. Green synthesis is especially important to minimize the harmful chemical and toxic by-products during the conventional synthesis of AuNPs. Green materials such as plants, fungi, microorganisms, enzymes and biopolymers are currently used to synthesize various NPs. Biosynthesized AuNPs are generally safer for use in biomedical applications since they come from natural materials themselves. Multiple surface functionalities of AuNPs allow them to be more robust and flexible when combined with different biological assemblies or modifications for enhanced applications. This review focuses on recent developments of green synthesized AuNPs and discusses their numerous biomedical applications. Sources of green materials with successful examples and other key parameters that determine the functionalities of AuNPs are also discussed in this review.

Nanodrug Delivery Systems for the Treatment of Ovarian Cancer

Despite advances achieved in medicine, chemotherapeutics still has detrimental side effects with ovarian cancer (OC), accounting for numerous deaths among females. The provision of safe, early detection and active treatment of OC remains a challenge, in spite of improvements in new antineoplastic discovery. Nanosystems have shown remarkable progress with impact in diagnosis and chemotherapy of various cancers, due to their ideal size; improved drug encapsulation within its interior core; potential to minimize drug degradation; improve in vivo drug release kinetics; and prolong blood circulation times. However, nanodrug delivery systems have few limitations regarding its accuracy of tumour targeting and the ability to provide sustained drug release. Hence, a cogent and strategic approach has focused on nanosystem functionalization with antibody-based ligands to selectively enhance cellular uptake of antineoplastics. Antibody functionalized nanosystems are (advanced) synthetic candidates, with a broad range of efficiency in specific tumour targeting, whilst leaving normal cells unaffected. This article comprehensively reviews the present status of nanosystems, with particular emphasis on nanomicelles for molecular diagnosis and treatment of OC. In addition, biomarkers of nanosystems provide important prospects as chemotherapeutic strategies to upsurge the survival rate of patients with OC.

A Novel Synthesis of Fe3O4@SiO2@Au@Porous SiO2 Structure for NIR Irradiation-Induced DOX Release and Cancer Treatment

Doxorubicin (DOX) alone or in combination has been widely used for numerous cancers, including breast, lung, bladder, and so on. In this article, a core/shell/shell structured Fe3O4@SiO2@Au@porous SiO2 particles for the drug delivery and release of DOX was demonstrated, with the aid of near-infrared irradiation. Fe3O4 was used to direct the transportation and delivery of the drug-loaded composite to the target tissues and organs under an external magnetic field, the first layer of SiO2 was used for Au nanoparticle attachment, Au acted as the agent for light-thermal conversion, and the porous SiO2 was used to load DOX. The morphology of the nanoparticles was studied by transmission electron microscopy, and the porous structure was characterized by N2 adsorption/desorption curves. The drug delivery system displayed high drug loading capacity, and the release behavior was largely impacted by the environmental pH. Furthermore, the cytotoxicity of Fe3O4@SiO2@Au@porous SiO2 and DOX loaded Fe3O4@SiO2@Au@porous SiO2 was studied through in vitro 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide cell viability assay.

Naturally derived nano- and micro-drug delivery vehicles: halloysite, vaterite and nanocellulose

We discuss prospects for halloysite nanotubes, vaterite crystals and nanocellulose to enter the market of biomaterials for drug delivery and tissue engineering, and their potential for economically viable production from abundant natural sources.

Cytotoxicity study and influence of SBA-15 surface polarity and pH on adsorption and release properties of anticancer agent pemetrexed

Mesoporous material SBA-15 was functionalized with different polar and nonpolar groups: 3-aminopropyl, (SBA-15-NH₂), 3-isocyanatopropyl (SBA-15-NCO), 3-mercaptopropyl (SBA-15-SH), methyl (SBA-15-CH₃) and phenyl (SBA-15-Ph). The resulting surface grafted materials were investigated as matrices for controlled drug delivery. Anticancer agent, pemetrexed (disodium pemetrexed heptahydrate) was selected as a model drug and loaded in the unmodified and functionalized SBA-15 materials. Materials were characterized by elemental analysis, infrared spectroscopy, transmission electron microscopy, nitrogen adsorption/desorption analysis, small angle X-ray scattering, powder X-ray diffraction, solid state NMR spectroscopy and thermogravimetry. It was shown that surface modification has an impact on both encapsulated drug amount and release properties. Release experiments were performed into two media with different pH: simulated body fluid (pH = 7.4) and simulated gastric fluid (pH = 2). In general, the effect of pH was reflected by the lower release of pemetrexed under acidic conditions (pH = 2) compared to slightly alkaline saline environment (pH = 7.4). The release rate of pemetrexed from propylamine-, propylisocyanate- and phenyl-modified SBA-15 was found to be effectively controlled by intermolecular interactions as compared to that from pure SBA-15, SBA-15-SH, and SBA-15-CH₃, that evidenced a steady and similar release. The highest release was observed for methyl-functionalized material whose hydrophobic surface accelerates the pemetrexed release. The data obtained from release studies were fitted using various kinetic models to determine the pemetrexed release mechanism and its release rate. The best correlations were found for Korsmeyer-Peppas and Higuchi models. Moreover, the theoretical three-parameter model for drug release kinetic was applied to calculate the strength of drug-support interactions. The in vitro cell study was performed on SKBR3 cancer cells and obtained results demonstrated that the modification of the mesoporous silica material by grafted polar/nonpolar groups may significantly affect the compatibility of this material with cells, drug release from this material and subsequent biological activity of PEM.

Antifungal activity of Copaíba resin oil in solution and nanoemulsion against Paracoccidioides spp

Paracoccidioidomycosis (PCM) is a disease caused by fungi of the genus Paracoccidioides. The disease is responsible for high rates of premature deaths and socioeconomic repercussions. The limitations of antifungal agents against PCM have motivated the search for new compounds. In our ongoing exploration of Cerrado plants as potential sources of new antifungal agents, we selected Copaifera langsdorffii oil (Copaíba resin oil) in order to explore its bioactive potential and test a formulation to increase oil stability and solubilization employing Pluronic F-127 to obtain the nanoemulsion of the oil. We aim at testing both Copaíba resin oil and its nanoemulsion against four species of the Paracoccidioides genus. We performed cytotoxicity test in Balb/C3T3 cells, hemolytic activity and interaction of Copaíba resin oil and Copaíba resin oil nanoemulsion (CopaPlu) with the antifungal agents such as amphotericin B, co-trimoxazole, and itraconazole. Moreover, the Copaíba resin oil was analyzed by mass spectrometry to identify its chemical profile. Eventually, a new methodology to prepare the nanoemulsion is presented. The Copaíba resin oil and CopaPlu nanoemulsion inhibited Paracoccidioides sp. growth efficiently, and no cytotoxicity or hemolytic effect was observed at minimum inhibitory concentration (MIC). When combined with amphotericin B, Copaíba resin oil and its nanoemulsion showed an additive effect with reduction of MIC values. The Copaíba resin oil and CopaPlu nanoemulsion is a promising antifungal agent against Paracoccidioides.

Evaluation of upconverting nanoparticles towards heart theranostics

Restricted and controlled drug delivery to the heart remains a challenge giving frequent off-target effects as well as limited retention of drugs in the heart. There is a need to develop and optimize tools to allow for improved design of drug candidates for treatment of heart diseases. Over the last decade, novel drug platforms and nanomaterials were designed to confine bioactive materials to the heart. Yet, the research remains in its infancy, not only in the development of tools but also in the understanding of effects of these materials on cardiac function and tissue integrity. Upconverting nanoparticles are nanomaterials that recently accelerated interest in theranostic nanomedicine technologies. Their unique photophysical properties allow for sensitive in vivo imaging that can be combined with spatio-temporal control for targeted release of encapsulated drugs.

Here we synthesized upconverting NaYF₄:Yb,Tm nanoparticles and show for the first time their innocuity in the heart, when injected in the myocardium or in the pericardial space in mice. Nanoparticle retention and upconversion in the cardiac region did not alter heart rate variability, nor cardiac function as determined over a 15-day time course ensuing the sole injection. Altogether, our nanoparticles show innocuity primarily in the pericardial region and can be safely used for controlled spatiotemporal drug delivery. Our results support the use of upconverting nanoparticles as potential theranostics tools overcoming some of the key limitations associated with conventional experimental cardiology.

Proof of concept of plasmonic thermal destruction of surface cancers by gold nanoparticles obtained by green chemistry

A greener approach for the design of surface plasmon resonant gold nanoparticles has been obtained with a hydrosoluble fraction of an endemic asteraceae medicinal plant. This medicinal plant is originated from Indian Ocean and demonstrates its bioreducing activity in the design of stable green nanomedicine in aqueous media. This article describes the preclinical assessment of the efficacy of these novel nanocandidates on murine model by intratumoral and intravenous injections. It definitely demonstrates two key points in the treatment of cancer: 1) optimization of the tumor microenvironment targeting by specific ligands for a limited damage on healthy tissue, 2) the need to screen the specific irradiation dose (time, power) taking into account the type of tumor.

Biofabrication And Antitumor Activity Of Silver Nanoparticles Utilizing Novel Nostoc sp. Bahar M

Background

Over recent years, green chemistry procedures have been developed to synthesize nanoparticles in eco-friendlier and less expensive ways. These procedures use natural sources such as bacteria, fungi, yeast, plants, actinomycetes, algae, or cyanobacteria, or use biomolecules such as proteins, vitamins, or pigments instead of chemical materials to fabricate salt precursors into nanoparticles.

Methodology

In the current investigation, we developed an effective, inexpensive, nontoxic method to synthesize silver nanoparticles (SNPs) using the cellular extract of a novel strain of cyanobacterium, Nostoc sp. Bahar M. SNPs were characterized using ultraviolet-visible spectroscopy, Fourier-transform infrared spectroscopy, X-ray diffraction, scanning electron microscopy, and transmission electron microscopy. The antitumor properties of the biogenic SNPs were tested against Caco-2 cells using a cell proliferation assay and inverted light microscopy.

Results

The new strain Nostoc sp. Bahar M was able to fabricate small SNPs from silver nitrate through an eco-friendly and inexpensive biosynthesis process. SNPs synthesis was accompanied by a color transformation from pale yellow to dark brown. Ultraviolet spectroscopy showed an absorption peak at 403 nm, confirming SNPs formation. X-ray diffraction analysis indicated that the SNPs had a face-centered cubic crystalline structure. Fourier-transform infrared spectroscopy was used to identify a protein that may play an important role in SNPs biosynthesis. Scanning and transmission electron micrographs showed that the SNPs were uniformly distributed and spherical in shape, with an average diameter of 14.9 nm. Cytotoxicity assays showed that SNPs exhibited a significant dose-dependent cytotoxic activity against human colon cancer cells with an IC₅₀ of 150 μg/mL.

Conclusion

Nostoc sp. Bahar M provided an eco-friendly route for fabricating SNPs, which have cytotoxic activity toward Caco-2 cells.

Bio-Mediated Synthesis and Characterisation of Silver Nanocarrier, and Its Potent Anticancer Action

Discovery of a potent drug nanocarrier is crucial for cancer therapy in which drugs often face challenges in penetrating efficiently into solid tumours. Here, biosynthesis of silver nanoparticles (AgNPs) using a waste material, Garcinia mangostana (GM) fruit peel extract is demonstrated. The best condition for AgNPs synthesis was with 0.5 g of peel extract, 7.5 mM silver nitrate at 45 °C, ~pH 4 for 16 h. The synthesized AgNPs were spherical and 32.7 ± 5.7 nm in size. To test its efficiency to be used as drug carrier, plant-based drug, protocatechuic acid (PCA) was used as a test drug. AgNPs loaded with PCA (AgPCA) resulted in 80% of inhibition at 15.6 µg/mL as compared to AgNPs which only killed 5% of HCT116 colorectal cells at same concentration. The IC₅₀ of AgNPs and AgPCA for HCT116 were 40.2 and 10.7 µg/mL, respectively. At 15.6 µg/mL, AgPCA was not toxic to the tested colon normal cells, CCD112. Ag-based drug carrier could also potentially reduce the toxicity of loaded drug as the IC₅₀ of PCA alone (148.1 µg/mL) was higher than IC₅₀ of AgPCA (10.7 µg/mL) against HCT116. Further, 24-h treatment of 15.6 µg/mL AgPCA resulted in loss of membrane potential in the mitochondria of HCT116 cells and increased level of reaction oxygen species (ROS). These could be the cellular killing mechanisms of AgPCA. Collectively, our findings show the synergistic anticancer activity of AgNPs and PCA, and its potential to be used as a potent anticancer drug nanocarrier.

Study on intracellular delivery of liposome encapsulated quantum dots using advanced fluorescence microscopy

Quantum dots increasingly gain popularity for in vivo applications. However, their delivery and accumulation into cells can be challenging and there is still lack of detailed information. Thereby, the application of advanced fluorescence techniques can expand the portfolio of useful parameters for a more comprehensive evaluation. Here, we encapsulated hydrophilic quantum dots into liposomes for studying cellular uptake of these so-called lipodots into living cells. First, we investigated photophysical properties of free quantum dots and lipodots observing changes in the fluorescence decay time and translational diffusion behaviour. In comparison to empty liposomes, lipodots exhibited an altered zeta potential, whereas their hydrodynamic size did not change. Fluorescence lifetime imaging microscopy (FLIM) and fluorescence correlation spectroscopy (FCS), both combined with two-photon excitation (2P), were used to investigate the interaction behaviour of lipodots with an insect epithelial tissue. In contrast to the application of free quantum dots, their successful delivery into the cytosol of salivary gland duct cells could be observed when applying lipodots. Lipodots with different lipid compositions and surface charges did not result in considerable differences in the intracellular labelling pattern, luminescence decay time and diffusion behaviour. However, quantum dot degradation after intracellular accumulation could be assumed from reduced luminescence decay times and blue-shifted luminescence signals. In addition to single diffusing quantum dots, possible intracellular clustering of quantum dots could be assumed from increased diffusion times. Thus, by using a simple and manageable liposome carrier system, 2P-FLIM and 2P-FCS recording protocols could be tested, which are promising for investigating the fate of quantum dots during cellular interaction.

Polymeric Mesoporous Silica Nanoparticles for Enhanced Delivery of 5-Fluorouracil In Vitro

There is a need for the improvement of conventional cancer treatment strategies by incorporation of targeted and non-invasive procedures aimed to reduce side-effects, drug resistance, and recurrent metastases. The anti-cancer drug, 5-fluorouracil (5-FU), is linked to a variety of induced-systemic toxicities due to its lack of specificity and potent administration regimens, necessitating the development of delivery vehicles that can enhance its therapeutic potential, while minimizing associated side-effects. Polymeric mesoporous silica nanoparticles (MSNs) have gained popularity as delivery vehicles due to their high loading capacities, biocompatibility, and good pharmacokinetics. MSNs produced in this study were functionalized with the biocompatible polymers, chitosan, and poly(ethylene)glycol to produce monodisperse NPs of 36-65 nm, with a large surface area of 710.36 m2/g, large pore volume, diameter spanning 9.8 nm, and a favorable zeta potential allowing for stability and enhanced uptake of 5-FU. Significant drug loading (0.15-0.18 mg5FU/mgmsn), controlled release profiles (15-65%) over 72 hours, and cell specific cytotoxicity in cancer cells (Caco-2, MCF-7, and HeLa) with reduced cell viability (≥50%) over the non-cancer (HEK293) cells were established. Overall, these 5FU-MSN formulations have been shown to be safe and effective delivery systems in vitro, with potential for in vivo applications.

Synthesis of Carum Carvi essential oil nanoemulsion, the cytotoxic effect, and expression of caspase 3 gene

Scientists are attempting to find novel methods to overcome cancers. Nanoemulsion systems as the novel drug delivery tools have been widely used in cancer therapy. In this study, the Carum Carvi oil nanoemulsions (CCONE) were prepared and its cytotoxic activity was studied on human colon cancer HT-29 cells using MTT assay. Flow cytometry and Real-time qPCR were triggered to evaluate the nanoemulsions' apoptotic properties. The results showed a significant negative association between the HT-29 cancer cell viability and CCONE doses of treatments compared with Huvec normal cells (p value < 0.001). The IC₅₀ values were estimated 12.5 µg/ml and 50 µg/ml for HT-29 and Huvec, respectively. Moreover, we observed that increasing concentrations of nanoemulsions significantly upregulate Caspase-3 gene expression. The results showed the CCONE is an efficient novel apoptosis inducer for human colon cancer cells without any undesirable side effects. However, further in vitro and in vivo researches are required. PRACTICAL APPLICATIONS: Cancer is a complex and usually untreatable disorder. Several types of cancer therapy strategies have been applied widely to overcome cancers. Chemotherapy has been used in various types of cancers. In most cases, not only it had not been effective on cancer cells but also been distractive within normal tissues. According to results, Carum Carvi essential oil nanoemulsions have apoptotic and cytotoxic effects on colon cancer cells (HT-29). When it comes to cancer of any kind, it's important to realize that no dietary supplement can fully treat, cure, or prevent cancer. However, there are some supplements that can potentially decrease the risk of cancer. Nanoemulsions present several advantages including the ability to incorporate hydrophilic, amphiphilic, and lipophilic excipient ingredients, high physical stability, and rapid gastrointestinal digestibility. The Carum Carvi essential oil nanoemulsion can also be applied as an effective food supplement due to its potent apoptotic activity.

Green Nanotechnology-Driven Drug Delivery Assemblies

Green nanotechnology incorporates the principles of green chemistry and green engineering to fabricate innocuous and eco-friendly nanoassemblies to combat the problems affecting the human health or environment. Subsequently, amalgamation of green nanotechnology with drug delivery area has actually commenced a new realm of "green nanomedicine". The burgeoning demand for green nanotechnology-driven drug delivery systems has led to the development of different types of delivery devices, like inorganic (metallic) nanoparticles, quantum dots, organic polymeric nanoparticles, mesoporous silica nanoparticles, dendrimers, nanostructured lipid carriers, solid lipid nanoparticles, etc. The present article deals with a brief account of delivery devices produced from green methods and describes site-specific drug delivery systems (including their pros and cons) and their relevance in the field of green nanomedicine.

Breathing new life into old antibiotics: overcoming antibacterial resistance by antibiotic-loaded nanogel carriers with cationic surface functionality

Multidrug-resistant pathogens are prevalent in chronic wounds. There is an urgent need to develop novel antimicrobials and formulation strategies that can overcome antibiotic resistance and provide a safe alternative to traditional antibiotics. This work aimed to develop a novel nanocarrier for two cationic antibiotics, tetracycline hydrochloride and lincomycin hydrochloride which can potentially overcome antibiotic resistance. In this study, we report the use of surface functionalised polyacrylic copolymer nanogels as carriers for cationic antibiotics. These nanogels can encapsulate small cationic antimicrobial molecules and act as a drug delivery system. They were further functionalised with a biocompatible cationic polyelectrolyte, bPEI, to increase their affinity towards the negatively charged bacterial cell walls. These bPEI-coated nanocarrier-encapsulated antibiotics were assessed against a range of wound isolated pathogens, which had been shown through antimicrobial susceptibility testing (AST) to be resistant to tetracycline and lincomycin. Our data reveal that bPEI-coated nanogels with encapsulated tetracycline or lincomycin displayed increased antimicrobial performance against selected wound-derived bacteria, including strains highly resistant to the free antibiotic in solution. Additionally, our nanocarrier-based antibiotics showed no detectable cytotoxic effect against human keratinocytes. We attribute the increase in the antimicrobial activity of the cationically functionalised antibiotic-loaded nanogel carriers to specific electrostatic adhesion to the microbial cell wall delivering a higher local antibiotic concentration, confirmed by scanning electron microscopy. Such a nanotechnology based approach may enhance the effectiveness of a wide variety of existing antibiotics, offering a potentially new mechanism to overcome antibiotic resistance.

Recent Advances in Degradable Hybrids of Biomolecules and NGs for Targeted Delivery

Recently, the fast development of hybrid nanogels dedicated to various applications has been seen. In this context, nanogels incorporating biomolecules into their nanonetworks are promising innovative carriers that gain great potential in biomedical applications. Hybrid nanogels containing various types of biomolecules are exclusively designed for: improved and controlled release of drugs, targeted delivery, improvement of biocompatibility, and overcoming of immunological response and cell self-defense. This review provides recent advances in this rapidly developing field and concentrates on: (1) the key physical consequences of using hybrid nanogels and introduction of biomolecules; (2) the construction and functionalization of degradable hybrid nanogels; (3) the advantages of hybrid nanogels in controlled and targeted delivery; and (4) the analysis of the specificity of drug release mechanisms in hybrid nanogels. The limitations and future directions of hybrid nanogels in targeted specific- and real-time delivery are also discussed.