Quantification of the force of nanoparticle-cell membrane interactions and its influence on intracellular trafficking of nanoparticles

The mechanical properties of lipid nanoparticles depend on the type of biomacromolecule they are loaded with

For drug delivery systems, the mechanical properties of drug carriers are suspected to play a crucial role in the delivery process. However, there is a lack of reliable methods available to measure the mechanical properties of drug carriers, which hampers the establishment of a link between delivery efficiency and the mechanical properties of carriers. Lipid nanoparticles (LNPs) are advanced systems for delivering nucleic acids to target cell populations for vaccination purposes (mRNA) or the development of new drugs. Hence, it is crucial to develop reliable techniques to measure the mechanical properties of LNPs. In this article, we used AFM to image and probe the mechanical properties of LNPs which are loaded with two different biopolymers either pDNA or mRNA. Imaging the LNPs before and after indentation, as well as recording the retraction curve, enables us to obtain more insight into how the AFM tip penetrates into the particle and to determine whether the deformation of the LNPs is reversible. For pDNA, the indentation by the tip leads to irreversible rupture of the LNPs, while the deformation is reversible for the mRNA-loaded LNPs. Moreover, the forces reached for pDNA are higher than for mRNA. These results pave the way toward the establishment of the link between the LNP formulation and the delivery efficiency.

Atomic Force Microscopy for the Study of Cell Mechanics in Pharmaceutics

Cell mechanics is gaining attraction in drug screening, but the applicable methods have not yet become part of the standardized norm. This review presents the current state of the art for atomic force microscopy, which is the most widely available method. The field is first motivated as a new way of tracking pharmaceutical effects, followed by a basic introduction targeted at pharmacists on how to measure cellular stiffness. The review then moves on to the current state of the knowledge in terms of experimental results and supplementary methods such as fluorescence microscopy that can give relevant additional information. Finally, rheological approaches as well as the theoretical interpretations are presented before ending on additional methods and outlooks.

Profiling to Probing: Atomic force microscopy to characterize nano-engineered implants

Surface modification of implants in the nanoscale or implant nano-engineering has been recognized as a strategy for augmenting implant bioactivity and achieving long-term implant success. Characterizing and optimizing implant characteristics is crucial to achieving desirable effects post-implantation. Modified implant enables tailored, guided and accelerated tissue integration; however, our understanding is limited to multicellular (bulk) interactions. Finding the nanoscale forces experienced by a single cell on nano-engineered implants will aid in predicting implants' bioactivity and engineering the next generation of bioactive implants. Atomic force microscope (AFM) is a unique tool that enables surface characterization and understanding of the interactions between implant surface and biological tissues. The characterization of surface topography using AFM to gauge nano-engineered implants' characteristics (topographical, mechanical, chemical, electrical and magnetic) and bioactivity (adhesion of cells) is presented. A special focus of the review is to discuss the use of single-cell force spectroscopy (SCFS) employing AFM to investigate the minute forces involved with the adhesion of a single cell (resident tissue cell or bacterium) to the surface of nano-engineered implants. Finally, the research gaps and future perspectives relating to AFM-characterized current and emerging nano-engineered implants are discussed towards achieving desirable bioactivity performances. This review highlights the use of advanced AFM-based characterization of nano-engineered implant surfaces via profiling (investigating implant topography) or probing (using a single cell as a probe to study precise adhesive forces with the implant surface). STATEMENT OF SIGNIFICANCE: Nano-engineering is emerging as a surface modification platform for implants to augment their bioactivity and achieve favourable treatment outcomes. In this extensive review, we closely examine the use of Atomic Force Microscopy (AFM) to characterize the properties of nano-engineered implant surfaces (topography, mechanical, chemical, electrical and magnetic). Next, we discuss Single-Cell Force Spectroscopy (SCFS) via AFM towards precise force quantification encompassing a single cell's interaction with the implant surface. This interdisciplinary review will appeal to researchers from the broader scientific community interested in implants and cell adhesion to implants and provide an improved understanding of the surface characterization of nano-engineered implants.

Rational nanoparticle design: Optimization using insights from experiments and mathematical models

Polymeric nanoparticles are highly tunable drug delivery systems that show promise in targeting therapeutics to specific sites within the body. Rational nanoparticle design can make use of mathematical models to organize and extend experimental data, allowing for optimization of nanoparticles for particular drug delivery applications. While rational nanoparticle design is attractive from the standpoint of improving therapy and reducing unnecessary experiments, it has yet to be fully realized. The difficulty lies in the complexity of nanoparticle structure and behavior, which is added to the complexity of the physiological mechanisms involved in nanoparticle distribution throughout the body. In this review, we discuss the most important aspects of rational design of polymeric nanoparticles. Ultimately, we conclude that many experimental datasets are required to fully model polymeric nanoparticle behavior at multiple scales. Further, we suggest ways to consider the limitations and uncertainty of experimental data in creating nanoparticle design optimization schema, which we call quantitative nanoparticle design frameworks.

Radiolabeled Liposomes for Nuclear Imaging Probes

Quantitative nuclear imaging techniques are in high demand for various disease diagnostics and cancer theranostics. The non-invasive imaging modality requires radiotracing through the radioactive decay emission of the radionuclide. Current preclinical and clinical radiotracers, so-called nuclear imaging probes, are radioisotope-labeled small molecules. Liposomal radiotracers have been rapidly developing as novel nuclear imaging probes. The physicochemical properties and structural characteristics of liposomes have been elucidated to address their long circulation and stability as radiopharmaceuticals. Various radiolabeling methods for synthesizing radionuclides onto liposomes and synthesis strategies have been summarized to render them biocompatible and enable specific targeting. Through a variety of radionuclide labeling methods, radiolabeled liposomes for use as nuclear imaging probes can be obtained for in vivo biodistribution and specific targeting studies. The advantages of radiolabeled liposomes including their use as potential clinical nuclear imaging probes have been highlighted. This review is a comprehensive overview of all recently published liposomal SPECT and PET imaging probes.

Current Techniques of Water Solubility Improvement for Antioxidant Compounds and Their Correlation with Its Activity: Molecular Pharmaceutics

The aqueous solubility of a drug is important in the oral formulation because the drug can be absorbed from intestinal sites after being dissolved in the gastrointestinal fluid, leading to its bioavailability. Almost 80% of active pharmaceutical ingredients are poorly water-soluble, including antioxidant compounds. This makes antioxidant activity inefficient in preventing disease, particularly for orally administered formulations. Although several investigations have been carried out to improve the solubility of antioxidant compounds, there is still limited research fully discussing the subject. Therefore, this study aimed to provide an overview and discussion of the issues related to the methods that have been used to improve the solubility and activity of antioxidant compounds. Articles were found using the keywords "antioxidant" and "water solubility improvement" in the Scopus, PubMed, and Google Scholar databases. The selected articles were published within the last five years to ensure all information was up-to-date with the same objectives. The most popular methods of the strategies employed were solid dispersion, co-amorphous, and nanoparticle drug delivery systems, which were used to enhance the solubility of antioxidant compounds. These investigations produced impressive results, with a detailed discussion of the mechanism of improvement in the solubility and antioxidant activity of the compounds developed. This review shows that the strategies used to increase the solubility of antioxidant compounds successfully improved their antioxidant activity with enhanced free radical scavenging abilities.

Effect of surface functionalization and loading on the mechanical properties of soft polymeric nanoparticles prepared by nano-emulsion templating

Drug and gene delivery systems based on polymeric nanoparticles offer a greater efficacy and a reduced toxicity compared to traditional formulations. Recent studies have evidenced that their internalization, biodistribution and efficacy can be affected, among other factors, by their mechanical properties. Here, we analyze by means of Atomic Force Microscopy force spectroscopy how composition, surface functionalization and loading affect the mechanics of nanoparticles. For this purpose, nanoparticles made of Poly(lactic-co-glycolic) (PLGA) and Ethyl cellulose (EC) with different functionalizations and loading were prepared by nano-emulsion templating using the Phase Inversion Composition method (PIC) to form the nano-emulsions. A multiparametric nanomechanical study involving the determination of the Young's modulus, maximum deformation and breakthrough force was carried out. The obtained results showed that composition, surface functionalization and loading affect the nanomechanical properties in a different way, thus requiring, in general, to consider the overall mechanical properties after the addition of a functionalization or loading. A graphical representation method has been proposed enabling to easily identify mechanically equivalent formulations, which is expected to be useful in the development of soft polymeric nanoparticles for pre-clinical and clinical use.

Advances in Lung Cancer Treatment Using Nanomedicines

Carcinoma of the lungs is among the most menacing forms of malignancy and has a poor prognosis, with a low overall survival rate due to delayed detection and ineffectiveness of conventional therapy. Therefore, drug delivery strategies that may overcome undesired damage to healthy cells, boost therapeutic efficacy, and act as imaging tools are currently gaining much attention. Advances in material science have resulted in unique nanoscale-based theranostic agents, which provide renewed hope for patients suffering from lung cancer. Nanotechnology has vastly modified and upgraded the existing techniques, focusing primarily on increasing bioavailability and stability of anti-cancer drugs. Nanocarrier-based imaging systems as theranostic tools in the treatment of lung carcinoma have proven to possess considerable benefits, such as early detection and targeted therapeutic delivery for effectively treating lung cancer. Several variants of nano-drug delivery agents have been successfully studied for therapeutic applications, such as liposomes, dendrimers, polymeric nanoparticles, nanoemulsions, carbon nanotubes, gold nanoparticles, magnetic nanoparticles, solid lipid nanoparticles, hydrogels, and micelles. In this Review, we present a comprehensive outline on the various types of overexpressed receptors in lung cancer, as well as the various targeting approaches of nanoparticles.

Actin depolymerizing factor-based nanomaterials: A novel strategy to enhance E. mitis-specific immunity

The epidemic of avian coccidiosis seriously threatens the animals' welfare and the economic gains of the poultry industry. Widespread in avian coccidiosis, Eimeria mitis (E. mitis) could obviously impair the production performance of the infected chickens. So far, few effective vaccines targeting E. mitis have been reported, and the nanovaccines composed of nanospheres captured our particular attention. At the present study, we construct two kinds of nanospheres carrying the recombinant E. mitis actin depolymerizing factor (rEmADF), then the characterization was then analyzed. After safety evaluation, the protective efficacy of rEmADF along with its nanospheres were investigated in chickens. The promoted secretions of antibodies and cytokines, as well as the enhanced percentages of CD4⁺ and CD8⁺ T cells were evaluated by the ELISA and flow cytometry assay. In addition, the absolute quantitative real-time PCR (qPCR) assay implied that vaccinations with rEmADF-entrapped nanospheres could significantly reduce the replications of E. mitis in feces. Compared with the rEmADF-loaded chitosan (EmADF-CS) nanospheres, the PLGA nanospheres carrying rEmADF (EmADF-PLGA nanosphers) were more effective in up-regulating weight efficiency of animals and generated equally ability in controlling E. mitis burdens in feces, suggesting the PLGA and CS nanospheres loaded with rEmADF were the satisfactory nanovaccines for E. mitis defense. Collectively, nanomaterials may be an effective antigen delivery system that could help recombinant E. mitis actin depolymerizing factor to enhance immunoprotections in chicken against the infections of E. mitis.

PLGA-based nanoparticles for the treatment of cancer: current strategies and perspectives

Research on cancer treatment is always of great importance because of the extensive and difficult treatment options and side effects of chemotherapeutic agents. Due to this, novel techniques for cancer treatment are the need of the day. Nowadays, nanotechnology is of great interest for its applications as diagnostic tools, theragnostic, contrasting agents, and vehicles for delivering drugs. Nanoparticles (NPs) are made up of biocompatible and biodegradable polymers that improve the pharmacokinetic and pharmacodynamic properties of drugs, reduce side effects, improve stability, prolong the release of drug, and reduce the dosing frequency. Poly (lactic-co-glycolic acid) (PLGA) is FDA-approved synthetic polymer which can be used to formulate NPs that can be targeted to a specific site for the safe and effective delivery of drugs. PLGA-based NPs can be used for a variety of cancer therapies including tumor-targeted drug delivery, gene therapy, hyperthermia, and photodynamic therapy. This article discusses the method of preparation, characterization, encapsulation of chemotherapeutic drugs, effect of physicochemical properties of PLGA- based NPs, and how we can exploit these aspects through various methods of preparation for drug loading, biodistribution, target specificity, and their use in cancer treatment. Along with these targeting strategies, gene therapy, cancer immunotherapy, and various applications have also been discussed. This article also aims to discuss the incorporation of diagnostic tools and therapeutic moiety in one versatile formulation of PLGA-NPs and the difficulties faced in translating this promising tool to clinical use.

A DFX-based iron nanochelator for cancer therapy

Iron as an essential element, is involved in various cellular functions and maintaining cell viability, cancer cell is more dependent on iron than normal cell due to its chief characteristic of hyper-proliferation. Despite that some of the iron chelators exhibited potent and broad antitumor activity, severe systemic toxicities have limited their clinical application. Polyaminoacids, as both drug-delivery platform and therapeutic agents, have attracted great interests owing to their different medical applications and biocompatibility. Herein, we have developed a novel iron nanochelator PL-DFX, which composed of deferasirox and hyperbranched polylysine. PL-DFX has higher cytotoxicity than DFX and this effect can be partially reversed by Fe2+ supplementation. PL-DFX also inhibited migration and invasion of cancer cells, interfere with iron metabolism, induce phase G1/S arrest and depolarize mitochondria membrane potential. Additionally, the anti-tumor potency of PL-DFX was also supported by organoids derived from clinical specimens. In this study, DFX-based iron nanochelator has provided a promising and prospective strategy for cancer therapy via iron metabolism disruption.

PLGA Nanospheres as Delivery Platforms for Eimeria mitis 1a Protein: A Novel Strategy to Improve Specific Immunity

The infections of chicken coccidiosis impact the welfare of chickens and the economical production of poultry. Eimeria mitis is ubiquitous in chicken coccidiosis, and E. mitis infection can significantly affect the productivity of birds. Up to now, few efficient vaccines against E. mitis have been reported, whereas the recombinant subunit vaccines delivered by nanomaterials may elicit an encouraging outcome. Thus, in this study, we chose E. mitis 1a (Em1a) protein as the candidate antigen to generate Em1a preparations. The recombinant Em1a (rEm1a) protein was encapsulated with poly lactic-co-glycolic acid (PLGA) and chitosan (CS) nanospheres. The physical characterization of the rEm1a-PLGA and rEm1a-CS nanospheres was investigated, and the resulting nanospheres were proven to be nontoxic. The protective efficacy of rEm1a-PLGA and rEm1a-CS preparations was evaluated in E. mitis-challenged birds in comparison with two preparations containing rEm1a antigen emulsified in commercially available adjuvants. ELISA assay, flow cytometry analysis, and quantitative real-time PCR (qPCR) analysis indicated that vaccination with rEm1a-loaded nanospheres significantly upregulated the secretions of antibodies and cytokines and proportions of CD4⁺ and CD8⁺ T lymphocytes. Compared with the other three preparations, rEm1a-PLGA nanosphere was more effective in improving growth performance and inhibiting oocyst output in feces, indicating that the PLGA nanosphere was associated with optimal protection against E. mitis. Collectively, our results highlighted the advantages of nanovaccine in eliciting protective immunity and may provide a new perspective for developing effective vaccines against chicken coccidiosis.

Em14-3-3 delivered by PLGA and chitosan nanoparticles conferred improved protection in chicken against Eimeria maxima

Eimeria maxima (E. maxima) are an intracellular apicomplexan protozoan that causes intestinal coccidiosis in chickens. The purpose of this research was to develop a novel delivery approach for recombinant E. maxima (rEm) 14-3-3 antigen to elicit enhanced immunogenic protection using poly (D, L-lactide-co-glycolide) (PLGA) and chitosan (CS) nanoparticles (NPs) against E. maxima challenge. The morphologies of prepared antigen-loaded NPs (PLGA/CS-rEm14-3-3 NPs) were visualized by a scanning electron microscope. The rEm14-3-3 and PLGA/CS-rEm14-3-3 NPs-immunized chicken-induced changes of serum cytokines, IgY-antibody level, and T-lymphocyte subsets and protective efficacies against E. maxima challenge were evaluated. The results revealed that encapsulated rEm14-3-3 in PLGA and CS NPs presented spherical morphology with a smooth surface. The chickens immunized with only rEm14-3-3 and PLGA/CS-rEm14-3-3 NPs elicited a significant (p<0.05) higher level of IFN-γ cytokine, stimulated the proportions of CD4⁺/CD3⁺, CD8⁺/CD3⁺ T-cells, and provoked sera IgY-antibody immune response compared to control groups (PBS, pET-32a, PLGA, and CS). Whereas, PLGA-rEm14-3-3 NP-immunized chicken provoked a higher level of IFN- γ production and IgY-antibody response rather than CS-rEm14-3-3 and bare antigen, relatively. The animal experiment results ratified that PLGA-rEm14-3-3 NP-immunized chicken significantly alleviated the relative body weight gain (%), decreased lesion score, and enhanced oocyst decrease ratio compared to CS-rEm14-3-3 NPs and only rEm14-3-3. The anti-coccidial index of the chicken vaccinated with the PLGA-rEm14-3-3 NPs was (180.1) higher than that of the Cs-rEm14-3-3 NPs (167.4) and bare antigen (165.9). Collectively, our statistics approved that PLGA NPs might be an efficient antigen carrier system (Em14-3-3) to act as a nanosubunit vaccine that can improve protective efficacies in chicken against E. maxima challenge.

Functional Nanomedicines for Targeted Therapy of Bladder Cancer

Bladder cancer is one of most common malignant urinary tract tumor types with high incidence worldwide. In general, transurethral resection of non-muscle-invasive bladder cancer followed by intravesical instillation of chemotherapy is the standard treatment approach to minimize recurrence and delay progression of bladder cancer. However, conventional intravesical chemotherapy lacks selectivity for tumor tissues and the concentration of drug is reduced with the excretion of urine, leading to frequent administration and heavy local irritation symptoms. While nanomedicines can overcome all the above shortcomings and adhere to the surface of bladder tumors for a long time, and continuously and efficiently release drugs to bladder cancers. The rapid advances in targeted therapy have led to significant improvements in drug efficacy and precision of targeted drug delivery to eradicate tumor cells, with reduced side-effects. This review summarizes the different available nano-systems of targeted drug delivery to bladder cancer tissues. The challenges and prospects of targeted therapy for bladder cancer are additionally discussed.

A numerical study on drug delivery via multiscale synergy of cellular hitchhiking onto red blood cells

Red blood cell (RBC)-hitchhiking, in which different nanocarriers (NCs) shuttle on the erythrocyte membrane and disassociate from RBCs to the first organ downstream of the intravenous injection spot, has recently been introduced as a solution to enhance target site uptake. Several experimental studies have already approved that cellular hitchhiking onto the RBC membrane can improve the delivery of a wide range of NCs in mice, pigs, and ex vivo human lungs. In these studies, the impact of NC size, NC surface chemistry, and shear rate on the delivery process and biodistribution has been widely explored. To shed light on the underlying physics in this type of drug delivery system, we present a computational platform in the context of the lattice Boltzmann method, spring connected network, and frictional immersed boundary method. The proposed algorithm simulates nanoparticle (NP) dislodgment from the RBC surface in shear flow and biomimetic microfluidic channels. The numerical simulations are performed for various NP sizes and RBC-NP adhesion strengths. In shear flow, NP detachment increases upon increasing the shear rate. RBC-RBC interaction can also significantly boost shear-induced particle detachment. Larger NPs have a higher propensity to be disconnected from the RBC surface. The results illustrate that changing the interaction between the NPs and RBCs can control the desorption process. All the findings agree with in vivo and in vitro experimental observations. We believe that the proposed setup can be exploited as a predictive tool to estimate optimum parameters in NP-bound RBCs for better targeting procedures in tissue microvasculature.

Nano-bio surface interactions, cellular internalisation in cancer cells and e-data portals of nanomaterials: A review

Nanomaterials (NMs) have abundant applications in areas such as electronics, energy, environment industries, biosensors, nano devices, theranostic platforms, etc. Nanoparticles can increase the solubility and stability of drug-loaded materials, enhance their internalisation, protect them from initial destruction in the biological system, and lengthen their circulation time. The biological interaction of proteins present in the body fluid with NMs can change the activity and natural surface properties of NMs. The size and charge of NMs, properties of the coated and uncoated NMs, nature of proteins, cellular interactions direct their internalisation pathway in the cellular system. Thus, the present review emphasises the impact of coated, uncoated NMs, size and charge, nature of proteins on nano-bio surface interactions and on internalisation with specific focus on cancer cells. The increased activity of NPs may also result in toxicity on health and environment, thus emphasis should be given to assess the toxicity of NMs in the medical field. The e-data sharing portals of NMs have also been discussed in this review that will be helpful in providing the information about the chemical, physical, biological properties and toxicity of NMs.

Raman spectroscopy and silver nanoparticles for efficient detection of membrane proteins in living cells

Molecular fingerprints revealed by Raman techniques show great potential for biomedical applications, like disease diagnostic through Raman detection of tumor markers and other molecules in the cell membrane. However, SERS substrates used in membrane molecule studies produce enhanced Raman spectra of high variability and challenging band assignments that limit their application. In this work, these drawbacks are addressed to detect membrane-associated hemoglobin (Hb_m) in human erythrocytes through Raman spectroscopy. These cells are incubated with silver nanoparticles (AgNPs) in PBS before Raman measurements. Our results showed that AgNPs form large aggregates in PBS that adhered to the erythrocyte membrane, which enhances Raman scattering by molecules around the membrane, like Hb_m. Also, deoxyHb markers may allow Hb_mdetection in Raman spectra of oxygenated erythrocytes (oxyRBCs). Raman spectra of oxyRBCs incubated with AgNPs showed enhanced deoxyHb signals with good spectral reproducibility, supporting the Hb_mdetection through deoxyHb markers. Instead, Raman spectra of oxyRBCs showed oxyHb bands associated with free cytoplasmic hemoglobin. Other factors influencing Raman detection of membrane proteins are discussed, like bothz-position and dimension of the sample volume. The results encourage membrane protein studies in living cells using Raman spectroscopy, leading to the characterization and diagnostic of different pathologies through a non-invasive technique.

Synthesis and Functionalisation of Superparamagnetic Nano-Rods towards the Treatment of Glioblastoma Brain Tumours

The complete removal of glioblastoma brain tumours is impossible to achieve by surgery alone due to the complex finger-like tentacle structure of the tumour cells and their migration away from the bulk of the tumour at the time of surgery; furthermore, despite aggressive chemotherapy and radiotherapy treatments following surgery, tumour cells continue to grow, leading to the death of patients within 15 months after diagnosis. The naturally occurring carnosine dipeptide has previously demonstrated activity against in vitro cultured glioblastoma cells; however, at natural physiological concentrations, its activity is too low to have a significant effect. Towards realising the full oncological potential of carnosine, the dipeptide was embedded within an externally triggered carrier, comprising a novel nano rod-shaped superparamagnetic iron oxide nanoparticle (ca. 86 × 19 × 11 nm) capped with a branched polyethyleneimine, which released the therapeutic agent in the presence of an external magnetic field. The new nano-carrier was characterized using electron microscopy, dynamic light scattering, elemental analysis, and magnetic resonance imaging techniques. In addition to cytotoxicity studies, the carnosine carrier’s effectiveness as a treatment for glioblastoma was screened in vitro using the U87 human glioblastoma astrocytoma cell line. The labile carnosine (100 mM) suppresses both the U87 cells’ proliferation and mobility over 48 h, resulting in significant reduction in migration and potential metastasis. Carnosine was found to be fully released from the carrier using only mild hyperthermia conditions (40 °C), facilitating an achievable clinical application of the slow, sustained-release treatment of glioblastoma brain tumours that demonstrates potential to inhibit post-surgery metastasis with the added benefit of non-invasive monitoring via MRI.

Escaping the endosome: assessing cellular trafficking mechanisms of non-viral vehicles

Non-viral vehicles hold therapeutic promise in advancing the delivery of a variety of cargos in vitro and in vivo, including small molecule drugs, biologics, and especially nucleic acids. However, their efficacy at the cellular level is limited by several delivery barriers, with endolysosomal degradation being most significant. The entrapment of vehicles and their cargo in the acidified endosome prevents access to the cytosol, nucleus, and other subcellular compartments. Understanding the factors that contribute to uptake and intracellular trafficking, especially endosomal entrapment and release, is key to overcoming delivery obstacles within cells. In this review, we summarize and compare experimental techniques for assessing the extent of endosomal escape of a variety of non-viral vehicles and describe proposed escape mechanisms for different classes of lipid-, polymer-, and peptide-based delivery agents. Based on this evaluation, we present forward-looking strategies utilizing information gained from mechanistic studies to inform the rational design of efficient delivery vehicles.

Light-assisted anticancer photodynamic therapy using porphyrin-doped nanoencapsulates

Light activatable porphyrinic photosensitizers (PSs) are essential components of anticancer and antimicrobial therapy and diagnostic imaging. However, their biological applications are quite challenging due to the lack of hydrophilicity and biocompatibility. To overcome such drawbacks, photosensitizers can be doped into a biocompatible polymer such as gelatin and further can be used for biomedical applications. Herein, first, a novel A4 type porphyrin PS [5,10,15,20-tetrakis(4-pyridylamidephenyl)porphyrin; TPyAPP] was synthesized via a rational route with good yield. Further, this porphyrin was encapsulated into the gelatin nanoparticles (GNPs) to develop hydrophilic phototherapeutic nanoagents (PTNAs, A4por-GNPs). Notably, the synthesis of such porphyrin-doped GNPs avoids the use of any toxic chemicals or solvents. The nanoprobes have also shown good fluorescence quantum yield demonstrating their applicability in bioimaging. Further, the mechanistic aspects of the anticancer and antimicrobial efficacy of the developed A4por-GNPs were evaluated via singlet oxygen generation studies. Overall, our results indicated porphyrin-doped biodegradable polymeric nanoparticles act as effective phototherapeutic agents against a broad range of cancer cell lines and microbes upon activation by the low-cost LED light.

Preclinical models and technologies to advance nanovaccine development

The remarkable success of targeted immunotherapies is revolutionizing cancer treatment. However, tumor heterogeneity and low immunogenicity, in addition to several tumor-associated immunosuppression mechanisms are among the major factors that have precluded the success of cancer vaccines as targeted cancer immunotherapies. The exciting outcomes obtained in patients upon the injection of tumor-specific antigens and adjuvants intratumorally, reinvigorated interest in the use of nanotechnology to foster the delivery of vaccines to address cancer unmet needs. Thus, bridging nano-based vaccine platform development and predicted clinical outcomes the selection of the proper preclinical model will be fundamental. Preclinical models have revealed promising outcomes for cancer vaccines. However, only few cases were associated with clinical responses. This review addresses the major challenges related to the translation of cancer nano-based vaccines to the clinic, discussing the requirements for ex vivo and in vivo models of cancer to ensure the translation of preclinical success to patients.

pH-Mediated nanoparticle dynamics in hydrogel nanocomposites

The effect of static silica particles on the dynamics of quantum dot (QD) nanoparticles grafted with a poly(ethylene glycol) (PEG) brush in hydrogel nanocomposites is investigated using single particle tracking (SPT). At a low volume fraction of homogeneously dispersed silica (Φ = 0.005), two distinct populations of PEG-QDs are observed, localized and mobile, whereas almost all PEG-QDs are mobile in neat hydrogel (Φ = 0.0). Increasing the silica particle concentration (Φ = 0.01, 0.1) results in an apparent change in the network structure, confounding the impact of silica on PEG-QD dynamics. The localized behavior of PEG-QDs is attributed to pH-mediated attraction between the PEG brush on the probe and surface silanol groups of silica. Using quartz crystal microbalance with dissipation (QCM-D), the extent of this interaction is investigated as a function of pH. At pH 5.8, the PEG brush on the probe can hydrogen bond with the silanol groups on silica, leading to adsorption of PEG-QDs. In contrast, at pH 9.2, silanol groups are deprotonated and PEG-QD is unable to hydrogen bond with silica leading to negligible adsorption. To test the effect of pH, PEG-QD dynamics are further investigated in hydrogel nanocomposites at Φ = 0.005. SPT agrees with the QCM-D results; at pH 5.8, PEG-QDs are localized whereas at pH 9.2 the PEG-QDs are mobile. This study provides insight into controlling probe transport through hydrogel nanocomposites using pH-mediated interactions, with implications for tuning transport of nanoparticles underlying drug delivery and nanofiltration.

Polymeric micelles in drug delivery: An insight of the techniques for their characterization and assessment in biorelevant conditions

Polymeric micelles, i.e. aggregation colloids formed in solution by self-assembling of amphiphilic polymers, represent an innovative tool to overcome several issues related to drug administration, from the low water-solubility to the poor drug permeability across biological barriers. With respect to other nanocarriers, polymeric micelles generally display smaller size, easier preparation and sterilization processes, and good solubilization properties, unfortunately associated with a lower stability in biological fluids and a more complicated characterization. Particularly challenging is the study of their interaction with the biological environment, essential to predict the real in vivo behavior after administration. In this review, after a general presentation on micelles features and properties, different characterization techniques are discussed, from the ones used for the determination of micelles basic characteristics (critical micellar concentration, size, surface charge, morphology) to the more complex approaches used to figure out micelles kinetic stability, drug release and behavior in the presence of biological substrates (fluids, cells and tissues). The techniques presented (such as dynamic light scattering, AFM, cryo-TEM, X-ray scattering, FRET, symmetrical flow field-flow fractionation (AF4) and density ultracentrifugation), each one with their own advantages and limitations, can be combined to achieve a deeper comprehension of polymeric micelles in vivo behavior. The set-up and validation of adequate methods for micelles description represent the essential starting point for their development and clinical success.

Enhanced immunogenicity of foot and mouth disease DNA vaccine delivered by PLGA nanoparticles combined with cytokine adjuvants

Although the immunogenicity of DNA vaccines is nonideal, they are still considered as potential alternative vaccine candidates to conventional vaccines. Various DNA delivery systems, including nanoparticles, have been extensively explored and validated to further enhance the immunogenicity of DNA vaccines. DNA vaccines are considered as alternative vaccine candidates. Various DNA delivery systems, including nanoparticles, have been extensively explored to enhance the immunogenicity of DNA vaccines. In this study, positively charged Poly (D, l-lactide-co-glycolic acid) (PLGA) nanoparticles were generated and characterized as a delivery system for O-serotype foot-and-mouth DNA vaccine. A recombinant plasmid encoding swine interleukin (IL)-18, IL-2, or granulocyte-macrophage colony-stimulating factor (GM-CSF) gene was introduced into the DNA vaccine to further improve its immunogenicity, which was evaluated in a guinea pig model. PLGA-pVAX-VP013/IL-18 elicited significantly (P = 0.0149) higher FMDV-specific antibody levels than naked DNA before the challenge. The level of neutralizing antibodies induced by PLGA-pVAX-VP013/IL-18, PLGA-pVAX-VP013/IL-2, and PLGA-pVAX-VP013/GM-CSF significantly increased compared with that induced by naked DNA (P < 0.0001). The lymphocyte proliferation assay showed that cellular immunity induced by PLGA-pVAX-VP013/IL-18 and PLGA-pVAX-VP013/GM-CSF was dramatically enhanced compared with that induced by the inactivated vaccine. The protection by PLGA-pVAX-VP013/IL-18 was consistent with that by the inactivated vaccine post-challenge and was followed by PLGA-pVAX-VP013/GM-CSF. Therefore, cationic PLGA nanoparticles can deliver DNA vaccines and induce humoral and cellular immune responses. The co-administration of FMD DNA vaccine with IL-18 formulated with PLGA nanoparticles was the optimal strategy to improve the immunogenicity of FMD DNA vaccines.

Macropinocytosis as a cell entry route for peptide-functionalized and bystander nanoparticles

Endocytic pathways provide the primary route for therapeutic and diagnostic nanoparticles (NPs) to enter cells and subcellular compartments. A better understanding of these cell entry processes will not only aid in nanomaterial applications but also broaden our knowledge of cell biology. Among the endocytic routes, macropinocytosis has unique characteristics for engulfing NPs and other large cargo, yet its molecular machinery and involvement in NP uptake are far less characterized relative to other pathways. In this review, we summarize the current knowledge on the macropinocytic machinery, and its involvement in NP internalization. Particularly, we differentiate ligand (specifically peptide)-functionalized and unfunctionalized NPs (bystander NPs). While most of previous research focused on ligand-functionalized NPs, we showcase here a synergistic effect between these two NP types during their cell entry through receptor-mediated macropinocytosis. The regulation of NP uptake efficiency by extracellular amino acids is also highlighted in the context of interconnections between macropinocytosis and metabolic signaling. These discussions may fuel future research interests in improving NP internalization through this pathway, and open a new avenue to study the interplay among endocytosis, metabolism and nanomedicine.

Endocytosis and Organelle Targeting of Nanomedicines in Cancer Therapy

Nanomedicines (NMs) have played an increasing role in cancer therapy as carriers to efficiently deliver therapeutics into tumor cells. For this application, the uptake of NMs by tumor cells is usually a prerequisite to deliver the cargo to intracellular locations, which mainly relies on endocytosis. NMs can enter cells through a variety of endocytosis pathways. Different endocytosis pathways exhibit different intracellular trafficking routes and diverse subcellular localizations. Therefore, a comprehensive understanding of endocytosis mechanisms is necessary for increasing cellular entry efficiency and to trace the fate of NMs after internalization. This review focuses on endocytosis pathways of NMs in tumor cells, mainly including clathrin- and caveolae-mediated endocytosis pathways, involving effector molecules, expression difference of those molecules between normal and tumor cells, as well as the intracellular trafficking route of corresponding endocytosis vesicles. Then, the latest strategies for NMs to actively employ endocytosis are described, including improving tumor cellular uptake of NMs by receptor-mediated endocytosis, transporter-mediated endocytosis and enabling drug activity by changing intracellular routes. Finally, active targeting strategies towards intracellular organelles are also mentioned. This review will be helpful not only in explicating endocytosis and the trafficking process of NMs and elucidating anti-tumor mechanisms inside the cell but also in rendering new ideas for the design of highly efficacious and cancer-targeted NMs.

Covalent Organic Framework Embedded with Magnetic Nanoparticles for MRI and Chemo-Thermotherapy

Nanoscale imine-linked covalent organic frameworks (nCOFs) were first loaded with the anticancer drug Doxorubicin (Dox), coated with magnetic iron oxide nanoparticles (γ-Fe₂O₃ NPs), and stabilized with a shell of poly(l-lysine) cationic polymer (PLL) for simultaneous synergistic thermo-chemotherapy treatment and MRI imaging. The pH responsivity of the resulting nanoagents (γ-SD/PLL) allowed the release of the drug selectively within the acidic microenvironment of late endosomes and lysosomes of cancer cells (pH 5.4) and not in physiological conditions (pH 7.4). γ-SD/PLL could efficiently generate high heat (48 °C) upon exposure to an alternating magnetic field due to the nCOF porous structure that facilitates the heat conduction, making γ-SD/PLL excellent heat mediators in an aqueous solution. The drug-loaded magnetic nCOF composites were cytotoxic due to the synergistic toxicity of Dox and the effects of hyperthermia in vitro on glioblastoma U251-MG cells and in vivo on zebrafish embryos, but they were not significantly toxic to noncancerous cells (HEK293). To the best of our knowledge, this is the first report of multimodal MRI probe and chemo-thermotherapeutic magnetic nCOF composites.

Cellular internalization mechanism of novel Raman probes designed for plant cells

Diphenylacetylene derivatives containing different polymeric components, poly(l-lysine) (pLys) or tetra(ethylene glycol) (TEG) were designed as novel Raman imaging probes with high Raman sensitivity and low cytotoxicity in living plant cells. The pLys-conjugated probe is internalized via an endocytosis-dependent pathway, whereas TEG-conjugated probe most likely induces direct penetration into the plant cells.

Diphenyl acetylene derivatives containing various polymeric components have been designed as new Raman imaging probes. These are taken up by plant cells via different pathways, and the internalization of exogenous molecules can be visualized.

A Comparison of Chitosan, Mesoporous Silica and Poly(lactic-co-glycolic) Acid Nanocarriers for Optimising Intestinal Uptake of Oral Protein Therapeutics

Efficacious oral delivery of therapeutic proteins remains challenging and nanoparticulate approaches are gaining interest for enhancing their permeability. In this study, we explore the ability for three comparably sized nanocarriers, with diverse physicochemical properties [i.e., chitosan (CSNP), mesoporous silica nanoparticles (MSNP) and poly(lactic-co-glycolic) acid (PLGA-NP)], to successfully facilitate epithelial uptake of a model protein, ovalbumin (OVA). We report the effect of nanoparticle surface chemistry and nanostructure on protein release, cell toxicity and the uptake mechanism in a Madin Darby Canine Kidney (MDCK) cell model of the intestinal epithelium. All nanocarriers exhibited bi-phasic OVA release kinetics with sustained and incomplete release after 4 days, and more pronounced release from MSNP than either polymeric nanocarriers. CSNP and MSNP displayed the highest cellular uptake, however CSNP was prone to significant dose-dependent toxicity attributed to the cationic surface charge. Approximately 25% of MSNP uptake was governed by a clathrin-independent endocytic mechanism, while CSNP and PLGA-NP uptake was not controlled via any endocytic mechanisms investigated herein. Furthermore, endosomal localisation was observed for CSNP and MSNP, but not for PLGA-NP. These findings may assist in the optimal choice and engineering of nanocarriers for specific intestinal permeation enhancement for oral protein delivery.

Phytol-Loaded Solid Lipid Nanoparticles as a Novel Anticandidal Nanobiotechnological Approach

Phytol is a diterpene alcohol and can be found as a product of the metabolism of chlorophyll in plants. This compound has been explored as a potential antimicrobial agent, but it is insoluble in water. In this study, we describe a novel approach for an interesting anticandidal drug delivery system containing phytol. Different formulations of phytol-loaded solid lipid nanoparticles (SLN) were designed and tested using a natural lipid, 1,3-distearyl-2-oleyl-glycerol (TG1). Different compositions were considered to obtain three formulations with 1:10, 1:5, and 1:3 w/w phytol/TG1 ratios. All the formulations were prepared by emulsification solvent evaporation method and had their physicochemical properties assessed. The biocompatibility assay was performed in the HEK-293 cell line and the antifungal efficacy was demonstrated in different strains of Candida ssp., including different clinical isolates. Spherical and uniform SLN (<300 nm, PdI < 0.2) with phytol-loading efficiency >65% were achieved. Phytol-loaded SLN showed a dose-dependent cytotoxic effect in the HEK-293 cell line. The three tested formulations of phytol-loaded SLN considerably enhanced the minimal inhibitory concentration of phytol against 15 strains of Candida spp. Considering the clinical isolates, the formulations containing the highest phytol/TG1 ratios showed MICs at 100%. Thus, the feasibility and potential of phytol-loaded SLN was demonstrated in vitro, being a promising nanocarrier for phytol delivery from an anticandidal approach.

Adhesion force spectroscopy with nanostructured colloidal probes reveals nanotopography-dependent early mechanotransductive interactions at the cell membrane level

Mechanosensing, the ability of cells to perceive and interpret the microenvironmental biophysical cues (such as the nanotopography), impacts strongly cellular behaviour through mechanotransductive processes and signalling. These events are predominantly mediated by integrins, the principal cellular adhesion receptors located at the cell/extracellular matrix (ECM) interface. Because of the typical piconewton force range and nanometre length scale of mechanotransductive interactions, achieving a detailed understanding of the spatiotemporal dynamics occurring at the cell/microenvironment interface is challenging; sophisticated interdisciplinary methodologies are required. Moreover, an accurate control over the nanotopographical features of the microenvironment is essential, in order to systematically investigate and precisely assess the influence of the different nanotopographical motifs on the mechanotransductive process. In this framework, we were able to study and quantify the impact of microenvironmental nanotopography on early cellular adhesion events by means of adhesion force spectroscopy based on innovative colloidal probes mimicking the nanotopography of natural ECMs. These probes provided the opportunity to detect nanotopography-specific modulations of the molecular clutch force loading dynamics and integrin clustering at the level of single binding events, in the critical time window of nascent adhesion formation. Following this approach, we found that the nanotopographical features are responsible for an excessive force loading in single adhesion sites after 20-60 s of interaction, causing a drop in the number of adhesion sites. However, by manganese treatment we demonstrated that the availability of activated integrins is a critical regulatory factor for these nanotopography-dependent dynamics.

c(RGDfK)- and ZnTriMPyP-Bound Polymeric Nanocarriers for Tumor-Targeted Photodynamic Therapy

Active targeting strategies are currently being extensively investigated in order to enhance the selectivity of photodynamic therapy. The aim of the present research was to evaluate whether the external decoration of nanopolymeric carriers with targeting peptides could add more value to a photosensitizer formulation and increase antitumor therapeutic efficacy and selectivity. To this end, we assessed PLGA-PLA-PEG nanoparticles (NPs) covalently attached to a hydrophilic photosensitizer 5-[4-azidophenyl]-10,15,20-tri-(N-methyl-4-pyridinium)porphyrinato zinc (II) trichloride (ZnTriMPyP) and also to c(RGDfK) peptides, in order to target α_v β₃ integrin-expressing cells. In vitro phototoxicity investigations showed that the ZnTriMPyP-PLGA-PLA-PEG-c(RGDfK) nanosystem is effective at submicromolar concentrations, is devoid of dark toxicity, successfully targets α_v β₃ integrin-expressing cells and is 10-fold more potent than related nanosystems where the PS is occluded instead of covalently bound.

Layer-by-layer assembled PLGA nanoparticles carrying miR-34a cargo inhibit the proliferation and cell cycle progression of triple-negative breast cancer cells

Triple-negative breast cancer (TNBC) accounts for 15-25% of diagnosed breast cancers, and its lack of a clinically defined therapeutic target has caused patients to suffer from earlier relapse and higher mortality rates than patients with other breast cancer subtypes. MicroRNAs (miRNAs) are small non-coding RNAs that regulate the expression of multiple genes through RNA interference to maintain normal tissue function. The tumor suppressor miR-34a is downregulated in TNBC, and its loss-of-expression correlates with worse disease outcomes. Therefore, delivering miR-34a mimics into TNBC cells is a promising strategy to combat disease progression. To achieve this goal, we synthesized layer-by-layer assembled nanoparticles (LbL NPs) comprised of spherical poly(lactic-co-glycolic acid) cores surrounded by alternating layers of poly-L-lysine (PLL) and miR-34a. TNBC cells internalized these LbL NPs to a greater extent than polyplexes comprised of PLL and miRNA, and confocal microscopy showed that LbL NPs delivered a substantial fraction of miR-34a cargo into the cytosol. This yielded robust suppression of the miR-34a target genes CCND-1, Notch-1, Bcl-2, Survivin, and MDR-1, which reduced TNBC cell proliferation and induced cell cycle arrest. These data validate that miR-34a delivery can impair TNBC cell function and support continued investigation of this platform for treatment of TNBC.

Accumulation and trafficking of zinc oxide nanoparticles in an invertebrate model, Bombyx mori, with insights on their effects on immuno-competent cells

Zinc oxide nanoparticles (ZnO NPs) are used in many applications; however, their interactions with cells, immune cells in particular, and potential health risk(s) are not fully known. In this manuscript, we have demonstrated the potential of ZnO NPs to cross the gut barrier in an invertebrate model, Bombyx mori, and that they can reach the hemolymph where they interact with and/or are taken up by immune-competent cells resulting in various toxic responses like decline in hemocyte viability, ROS generation, morphological alterations, apoptotic cell death, etc. Exposure to these NPs also resulted in alteration of hemocyte dynamics including an immediate increase in THC, possibly due to the release of these hemocytes either from enhanced rate of cell divisions or from attached hemocyte populations, and decline in percentage of prohemocytes and increase in percentage of two professional phagocytes, i.e., granulocytes and plasmatocytes, possibly due to the differentiation of prohemocytes into phagocytes in response to a perceived immune challenge posed by these NPs. Taken together, our data suggest that ZnO NPs have the potential to cross gut barrier and cause various toxic effects that could reverse and the insects could return to normal physiological states as there is restoration and repair of various systems and their affected pathways following the clearance of these NPs from the insect body. Our study also indicates that B. mori has the potential to serve as an effective alternate animal model for biosafety, environmental monitoring and screening of NPs, particularly to evaluate their interactions with invertebrate immune system.

Multi-stimuli-responsive nanomicelles fabricated using synthetic polymer polylysine conjugates for tumor microenvironment dependent drug delivery

A poly(lysine)-synthetic polymer hybrid nanomicelles were fabricated as promising platform for efficient tumor targeting and glutathione/pH/temperature-responsive anticancer drug delivery.

Transcytosis of Nanomedicine for Tumor Penetration

The diffusion of nanomedicines used to treat tumors is severely hindered by the microenvironment, which is a challenge that has emerged as a bottleneck for the effective outcome of nanotherapies. Classical strategies for enhancing tumor penetration rely on passive movement in the extracellular matrix (ECM). Here, we demonstrate that nanomedicine also penetrates tumor lesions via an active trans-cell transportation process. This process was discovered by directly observing the movement of nanoparticles between cells, evaluating the intracellular trafficking pathway of nanoparticles via Rab protein labeling, comparing endocytosis-exocytosis between nanoparticles administered with inhibitors, and correlating the transcytosis process with the micro-CT distribution of nanomedicines. We also demonstrated that enhanced tumor penetration promotes the therapeutic efficacy of a photodynamic therapeutic nanomedicine. Our research thus suggests that transcytosis could be an important positive factor for designing cancer nanomedicines.

PLGA based particles as "drug reservoir" for antitumor drug delivery: characterization and cytotoxicity studies

Doxorubicin (DOX) is commonly used to treat several tumor types, but its severe side effects, primarily cardiotoxicity, represent a major limitation for its use in clinical settings. In this study we developed and characterized biodegradable and stable poly(D,L-lactic-co-glycolic) acid (PLGA) submicrocarriers employing an osmosis-based patented methodology, which allowed to optimize the drug loading efficiency up to 99%. Proceeding from this, we evaluated on MCF-7, a human breast cancer cell line, the ability of PLGA to promote the internalization of DOX and to improve its cytotoxicity in vitro. We found that the in vitro uptake efficiency is dramatically increased when DOX is loaded within PLGA colloidal carriers, which adhere to the cell membrane behaving as an efficient drug reservoir. In fact, the particles provide a diffusion-driven, sustained release of DOX across the cell membrane, resulting in high drug concentration. Accordingly, the cytotoxic analysis clearly showed that DOX-loaded PLGA exhibit a lower 50% inhibitory concentration than free DOX. The decay time of cell viability was successfully compared with DOX diffusion time constant from PLGA. The overall in vitro results highlight the potential of DOX-loaded PLGA particles to be employed as vectors with improved antitumor efficacy.

Kinetics of Nanoparticle-Membrane Adhesion Mediated by Multivalent Interactions

Multivalent adhesive interactions mediated by a large number of ligands and receptors underpin many biological processes, including cell adhesion and the uptake of particles, viruses, parasites, and nanomedical vectors. In materials science, multivalent interactions between colloidal particles have enabled unprecedented control over the phase behavior of self-assembled materials. Theoretical and experimental studies have pinpointed the relationship between equilibrium states and microscopic system parameters such as the ligand-receptor binding strength and their density. In regimes of strong interactions, however, kinetic factors are expected to slow down equilibration and lead to the emergence of long-lived out-of-equilibrium states that may significantly influence the outcome of self-assembly experiments and the adhesion of particles to biological membranes. Here we experimentally investigate the kinetics of adhesion of nanoparticles to biomimetic lipid membranes. Multivalent interactions are reproduced by strongly interacting DNA constructs, playing the role of both ligands and receptors. The rate of nanoparticle adhesion is investigated as a function of the surface density of membrane-anchored receptors and the bulk concentration of nanoparticles and is observed to decrease substantially in regimes where the number of available receptors is limited compared to the overall number of ligands. We attribute such peculiar behavior to the rapid sequestration of available receptors after initial nanoparticle adsorption. The experimental trends and the proposed interpretation are supported by numerical simulations.

Direct and Noninvasive Penetration of Bare Hydrophobic Quantum Dots through Live Cell Membranes

Semiconductor quantum dots (QDs) possess outstanding optical properties as fluorescent probes, but their applications in live cell intracellular imaging are hindered by various cellular transport barriers. Inspired by membrane proteins inserting their nanometer-scale hydrophobic surface into biomembranes, the present work aims to investigate the possibility that bare hydrophobic QDs could penetrate through live cell membranes without disrupting the membrane integrity. We utilize live cell spinning disk confocal microscopy to image and track the cellular transport process of bare hydrophobic QDs in the presence of a small percentage of three different organic cosolvents, namely, tetrahydrofuran (THF), chloroform, and hexane. A major finding is that, under certain cosolvent conditions, bare hydrophobic QDs can indeed penetrate through biomembranes in a noninvasive manner. Results of this work offer us guidance to design a new class of nanobioprobes based on combining hydrophobic nanoscale surface and cosolvent, and they provide key new pieces to the emerging complex and sophisticated picture of nanostructure-biosystem interactions.