Sustained zero-order release of intact ultra-stable drug-loaded liposomes from an implantable nanochannel delivery system

68 Ga-labeled, imatinib encapsulated, theranostic liposomes: Formulation, characterization, and in vitro evaluation of anticancer activity

Cancer is still a global health problem. Among cancer types, breast cancer is the most frequently diagnosed one, and it causes a high mortality rate if not diagnosed in the early stages. In our study, imatinib encapsulated, nanosized, neutral/cationic liposome formulations were prepared as theranostic agents for breast cancer. After the characterization studies in which all liposomes exhibited proper profile owing to their particle size between 133 and 250 nm, polydispersity index values lower than 0.4, neutral and cationic zeta potential values, and high drug encapsulation efficiency, controlled drug release behaviors with zero-order kinetic were obtained. The higher than 90% radiolabeling efficiency values were obtained thanks to the determination of optimum radiolabeling condition (80°C temperature, 5 mCi radioactivity, and 10 min incubation period). According to the resazurin assay evaluating the cytotoxic profile of liposomes on MCF7 cells, neutral empty liposome was found as biocompatible, while both cationic liposomes (empty and drug-loaded ones) exhibited high nonspecific cytotoxicity at even low drug concentration due to the existence of stearyl amine in the formulations. However, dose-dependent cytotoxic effect and the highest cellular binding capacity were obtained by imatinib loaded neutral liposomes. In conclusion, 68 Ga-radiolabeled, imatinib-loaded, neutral, nanosized liposome formulation is the most promising one as a theranostic agent among all formulations.

Co-delivery of lapatinib and 5-fluorouracil transfersomes using transpapillary iontophoresis for breast cancer therapy

Combination chemotherapy, involving the intervention of two or more anti-neoplastic agents has been the cornerstone in breast cancer treatment, owing to the applications it holds in contrast to the mono-therapy approach. This research predominantly focussed on proving the synergy between Lapatinib (LPT) and 5-Fluorouracil (5-FU) and further enhancing its localized permeation via transfersome-loaded delivery and iontophoresis to treat breast tumors. The IC50 values for LPT and 5-FU were found to be 19.38 µg/ml and 5.7 µg/ml respectively and their synergistic effect was proven by the Chou-Talalay assay using CompuSyn software. Furthermore, LPT and 5-FU were encapsulated within transfersomes and administered via the transpapillary route. The drug-loaded carriers were characterized for their particle size, polydispersity index, zeta potential, and entrapment efficiency. The ex vivo rat skin permeation studies indicated that when compared to LPT dispersion and 5-FU solution, drug-loaded transfersomes exhibited better permeability and their transpapillary permeation was enhanced on using iontophoresis. Moreover, both LPT and 5-FU transfersomes were found to be stable for 3 months when stored at a temperature of 5 ± 3 °C. The results indicated that this treatment strategy could be an effective approach in contrast to some of the conventional treatments employed to date.

99mTc-Labeled, Colistin Encapsulated, Theranostic Liposomes for Pseudomonas aeruginosa Infection

Infectious diseases are still the major issue not only due to antibiotic resistance but also causing deaths if not diagnosed at early-stages. Different approaches including nanosized drug delivery systems and theranostics are researched to overcome antibiotic resistance, decrease the side effects of antibiotics, improve the treatment response, and early diagnose. Therefore, in the present study, nanosized, radiolabeled with ^99mTc, colistin encapsulated, neutral and cationic liposome formulations were prepared as the theranostic agent for Pseudomonas aeruginosa infections. Liposomes exhibited appropriate physicochemical properties thanks to their nano-particle size (between 173 and 217 nm), neutral zeta potential value (about - 6.5 and 2.8 mV), as well as encapsulation efficiency of about 75%. All liposome formulations were radiolabeled with over 90% efficiency, and the concentration of stannous chloride was found as 1 mg.mL^-1 to obtain maximum radiolabeling efficiency. In alamar blue analysis, neutral liposome formulations were found more biocompatible compared with the cationic formulations. Neutral colistin encapsulated liposomes were found to be more effective against P. aeruginosa strain according to their time-dependent antibacterial effect, in addition to their highest bacterial binding capacity. As conclusion, theranostic, nanosized, colistin encapsulated, neutral liposome formulations were found as promising agents for the imaging and treating of P. aeruginosa infections.

New iron(III) anti-cancer aminobisphenolate/phenanthroline complexes: Enhancing their therapeutic potential using nanoliposomes

Malignant melanoma is an aggressive and deadly form of skin cancer and novel and improved therapeutic options are needed. A promising strategy involves the use of metallodrugs combined with liposomes for targeted delivery to cancer cells. In this work, a family of iron(III) complexes was synthesized bearing a trianionic aminobisphenolate ligand (L) and phenanthroline-type co-ligands (NN). Four ternary iron complexes of general formula [Fe(L)(NN)] were obtained: [Fe(L)(amphen)] (1), [Fe(L)(phen)] (2), [Fe(L)(Clphen)] (3), and [Fe(L)(Mephen)] (4), as well as a fifth complex [Fe(L)(NEt₃)(H₂O)] (5) without the bidentate co-ligand. All complexes were characterized by analytic and spectroscopic techniques and demonstrated to be stable in aqueous environment. Complexes 1 and 2 were able to bind DNA and presented high cytotoxic activity towards human cancer cells. Complex 1 (IronC) was selected for incorporation into different liposomal formulations, which were fully characterized and screened against murine melanoma cells. The IronC liposomal formulation with the highest incorporation efficiency (∼95%) and a low IC₅₀ value (7.1 ± 0.7 μM) was selected for in vivo evaluation. In a syngeneic murine melanoma model the liposomal formulation of IronC yielded the highest impairment on tumour progression when compared with the control, temozolomide, and with the iron complex in free form.

Using UV-Responsive Nanoparticles to Provide In Situ Control of Growth Factor Delivery and a More Constant Release Profile from a Hydrogel Environment

Nanoparticles are popular delivery vehicles, but their diffusional release results in inconstant drug delivery. Here, we flatten the delivery profile into a more constant, zero-order profile. Brain-derived neurotrophic factor (BDNF) is attached to photoactive titanium dioxide nanoparticles and loaded into a nanofibrous self-assembling peptide (SAP) hydrogel. Different UV exposure conditions show three distinct profiles, including a counterintuitive decrease in release after UV exposure. We propose that the adsorption of the freed growth factor onto the hydrogel nanofibers affects release. Nanoparticles diffuse from the hydrogel readily, carrying the bound growth factor, but the freed growth factor (released from the nanoparticles by UV) instead interacts with─and is released less readily from─the hydrogel. UV shifts growth factor from nanoparticles to the hydrogel, therefore changing the diffusional release. Through midpoint UV exposure, we achieve a flattened delivery profile─unusual for diffusion─by changing in situ the amount of growth factor bound to the diffusing nanoparticles. With nanoparticle diffusion alone, we observed an increasing release profile with 36% of release in the first 6 h and 64% in the second 6 h. With midway UV exposure, this was controlled to 49 and 51%, respectively. The release of an unbound (soluble) control growth factor, glial cell-line derived neurotrophic factor (GDNF), was not affected by UV treatment, demonstrating the potential for independent control of temporal delivery profiles in a multiagent material.

Current understandings and clinical translation of nanomedicines for breast cancer therapy

Breast cancer is one of the most frequently diagnosed cancers that is threatening women's life. Current clinical treatment regimens for breast cancer often involve neoadjuvant and adjuvant systemic therapies, which somewhat are associated with unfavorable features. Also, the heterogeneous nature of breast cancers requires precision medicine that cannot be fulfilled by a single type of systemically administered drug. Taking advantage of the nanocarriers, nanomedicines emerge as promising therapeutic agents for breast cancer that could resolve the defects of drugs and achieve precise drug delivery to almost all sites of primary and metastatic breast tumors (e.g. tumor vasculature, tumor stroma components, breast cancer cells, and some immune cells). Seven nanomedicines as represented by Doxil® have been approved for breast cancer clinical treatment so far. More nanomedicines including both non-targeting and active targeting nanomedicines are being evaluated in the clinical trials. However, we have to realize that the translation of nanomedicines, particularly the active targeting nanomedicines is not as successful as people have expected. This review provides a comprehensive landscape of the nanomedicines for breast cancer treatment, from laboratory investigations to clinical applications. We also highlight the key advances in the understanding of the biological fate and the targeting strategies of breast cancer nanomedicine and the implications to clinical translation.

Oleuropein multicompartment nanovesicles enriched with collagen as a natural strategy for the treatment of skin wounds connected with oxidative stress

Aim: Collagen-enriched transfersomes, glycerosomes and glytransfersomes were specifically tailored for skin delivery of oleuropein. Methods: Vesicles were prepared by direct sonication and their main physicochemical and technological properties were measured. Biocompatibility, protective effect and promotion of the healing of a wounded cell monolayer were tested in vitro using fibroblasts. Results: Vesicles were mainly multicompartment, small (∼108 nm), slightly polydispersed (approximately 0.27) and negatively charged (~-49 mV). Oleuropein was incorporated in high amounts (approximately 87%) and vesicles were stable during four months of storage. In vitro studies confirmed the low toxicity of formulations (viability ≥95%), their effectiveness in counteracting nitric oxide generation and damages caused by free oxygen radicals, especially when collagen glytransfersomes were used (viability ~100%). These vesicles also promoted the regeneration of a wounded area by promoting the proliferation and migration of fibroblasts. Conclusion: Collagen-enriched vesicles are promising formulations capable of speeding up the healing of the wounded skin.

Silymarin (milk thistle extract) as a therapeutic agent in gastrointestinal cancer

Silymarin contains a group of closely-related flavonolignan compounds including silibinin, and is extracted from Silybum marianum species, also called milk thistle. Silymarin has been shown to protect the liver in both experimental models and clinical studies. The chemopreventive activity of silymarin has shown some efficacy against cancer both in vitro and in vivo. Silymarin can modulate apoptosis in vitro and survival in vivo, by interfering with the expression of cell cycle regulators and apoptosis-associated proteins. In addition to its anti-metastatic activity, silymarin has also been reported to exhibit anti-inflammatory activity. The chemoprotective effects of silymarin and silibinin (its major constituent) suggest they could be applied to reduce the side effects and increase the anti-cancer effects of chemotherapy and radiotherapy in various cancer types, especially in gastrointestinal cancers. This review examines the recent studies and summarizes the mechanistic pathways and down-stream targets of silymarin in the therapy of gastrointestinal cancer.

Nanonutraceuticals: The New Frontier of Supplementary Food

In the last few decades, the combination between nanotechnology and nutraceutics has gained the attention of several research groups. Nutraceuticals are considered as active compounds, abundant in natural products, showing beneficial effects on human health. Unfortunately, the uses, and consequently the health benefits, of many nutraceutical products are limited by their unsuitable chemico-physical features. For example, many nutraceuticals are characterized by low water solubility, low stability and high susceptibility to light and oxygen, poor absorption and potential chemical modifications after their administration. Based on the potential efficacy of nutraceuticals and on their limiting features, nanotechnology could be considered a revolutionary innovation in empowering the beneficial properties of nutraceuticals on human health, thus enhancing their efficacy in several diseases. For this reason, nanotechnology could represent a new frontier in supplementary food. In this review, the most recent nanotechnological approaches are discussed, focusing on their ability to improve the bioavailability of the most common nutraceuticals, providing an overview regarding both the advantages and the possible limitations of the use of several nanodelivery systems. In fact, although the efficacy of smart nanocarriers in improving health benefits deriving from nutraceuticals has been widely demonstrated, the conflicting opinions on the mechanism of action of some nanosystems still reduce their applicability in the therapeutic field.

Flow Cytometry Analysis of Circulating Extracellular Vesicle Subtypes from Fresh Peripheral Blood Samples

Extracellular vesicles (EVs) are released by shedding during different physiological processes and are increasingly thought to be new potential biomarkers. However, the impact of pre-analytical processing phases on the final measurement is not predictable and for this reason, the translation of basic research into clinical practice has been precluded. Here we have optimized a simple procedure in combination with polychromatic flow cytometry (PFC), to identify, classify, enumerate, and separate circulating EVs from different cell origins. This protocol takes advantage of a lipophilic cationic dye (LCD) able to probe EVs. Moreover, the application of the newly optimized PFC protocol here described allowed the obtainment of repeatable EVs counts. The translation of this PFC protocol to fluorescence-activated cell sorting allowed us to separate EVs from fresh peripheral blood samples. Sorted EVs preparations resulted particularly suitable for proteomic analyses, which we applied to study their protein cargo. Here we show that LCD staining allowed PFC detection and sorting of EVs from fresh body fluids, avoiding pre-analytical steps of enrichment that could impact final results. Therefore, LCD staining is an essential step towards the assessment of EVs clinical significance.

Diameters and Fluorescence Calibration for Extracellular Vesicle Analyses by Flow Cytometry

Extracellular vesicles (EVs) play a crucial role in the intercellular crosstalk. Mesenchymal stem cell-derived EVs (MSC-EVs), displaying promising therapeutic roles, contribute to the strong rationale for developing EVs as an alternative therapeutic option. EV analysis still represents one of the major issues to be solved in order to translate the use of MSC-EV detection in clinical settings. Even if flow cytometry (FC) has been largely applied for EV studies, the lack of consensus on protocols for FC detection of EVs generated controversy. Standard FC procedures, based on scatter measurements, only allows the detection of the “tip of the iceberg” of all EVs. We applied an alternative FC approach based on the use of a trigger threshold on a fluorescence channel. The EV numbers obtained by the application of the fluorescence triggering resulted significantly higher in respect to them obtained from the same samples acquired by placing the threshold on the side scatter (SSC) channel. The analysis of EV concentrations carried out by three different standardized flow cytometers allowed us to achieve a high level of reproducibility (CV < 20%). By applying the here-reported method highly reproducible results in terms of EV analysis and concentration measurements were obtained.

Liposomes for Intra-Articular Analgesic Drug Delivery in Orthopedics: State-of-Art and Future Perspectives. Insights from a Systematic Mini-Review of the Literature

Background and objectives: Liposomal structures are artificial vesicles composed of one or several lamellae of phospholipids which surround an inner aqueous core. Given the amphoteric nature of phospholipids, liposomes are promising systems for drug delivery. The present review provides an updated synthesis of the main techniques for the production of liposomes for orthopedic applications, focusing on the drawbacks of the conventional methods and on the advantages of high pressure techniques. Materials and Methods: Articles published in any language were systematically retrieved from two major electronic scholarly databases (PubMed/MEDLINE and Scopus) up to March 2020. Nine articles were retained based on the “Preferred Reporting Items for Systematic Reviews and Meta-Analyses” (PRISMA) guidelines. Results: Liposome vesicles decrease the rate of inflammatory reactions after local injections, and significantly enhance the clinical effectiveness of anti-inflammatory agents providing controlled drug release, reducing toxic side effects. Conclusions: This review presents an update on the improvement in musculoskeletal ailments using liposome treatment.

Ammonium glycyrrhizate skin delivery from ultradeformable liposomes: A novel use as an anti-inflammatory agent in topical drug delivery

Glycyrrhiza glabra L. is a native plant of Central and South-Western Asia that is also diffused in the Mediterranean area and contains several bioactive compounds such as: flavonoids, sterols, triterpene and saponins. Glycyrrhizin, containing glycyrrhizic and glycyrrhizinic acids has anti-inflammatory and antiallergic effects that are similar to corticosteroids. Ammonium glycyrrhizinate is a derivative salt of glycyrrhizic acid with similar anti-inflammatory activity that cannot pass through the skin due to its physicochemical properties and molecular weight. Although several nanoformulations, such as ethosomes, are designed to provide a systemic effect through a topical application, there are different limitations to the distribution inside the blood stream. For this reason, ultradeformable liposomes, or transfersomes, are selected to improve the topical delivery of drugs and allow the distribution of payloads in the blood stream because they pass intact through the stratum corneum epidermis barrier, due to the presence of sodium cholate, aqueous cutaneous gradient, and the rapid penetration of transfersomes by cutaneous tight junctions, thus allowing the systemic delivery of different therapeutic cargo in non-occlusive conditions. The aim of this work was the synthesis and physicochemical characterization of the ammonium glycyrrhizinate-loaded ultradeformable liposomes, the evaluation of drug release and permeation through stratum corneum and epidermis barrier. The in vivo anti-inflammatory effect of ammonium glycyrrhizinate-loaded ultradeformable liposomes was tested on human healthy volunteers. The results demonstrated that the ammonium glycyrrhizinate-loaded ultradeformable liposomes decreased the skin inflammation on the human volunteers and the resulting nanoformulations can be used as a potential topical drug delivery system for anti-inflammatory therapy. ^☆Parts of these results were presented as a poster communication at the Recent Developments in Pharmaceutical Analysis 2019 (RDPA 2019), Chieti, Italy.

Electrostatically gated nanofluidic membrane for ultra-low power controlled drug delivery

Patient-centered therapeutic management for chronic medical conditions is a desired but unmet need, largely attributable to the lack of adequate technologies for tailored drug administration. While triggered devices that control the delivery of therapeutics exist, they often rely on impractical continuous external activation. As such, next generation continuously tunable drug delivery systems independent of sustained external activation remain an elusive goal. Here we present the development and demonstration of a silicon carbide (SiC)-coated nanofluidic membrane that achieves reproducible and tunable control of drug release via electrostatic gating. By applying a low-intensity voltage to a buried electrode, we showed repeatable and reproducible in vitro release modulation of three model analytes. A small fluorophore (Alexa Fluor 647), a large polymer poly(sodium 4-styrenesulfonate) and a medically relevant agent (DNA), were selected as representatives of small molecule therapeutics, polymeric drug carriers, and biological therapeutics, respectively. Unlike other drug delivery systems, our technology performed consistently over numerous cycles of voltage modulation, for over 11 days. Importantly, low power consumption and minimal leakage currents were achieved during the study. Further, the SiC coating maintained integrity and chemical inertness, shielding the membrane from degradation under simulated physiological and accelerated conditions for over 4 months. Through leveraging the flexibility offered by electrostatic gating control, our technology provides a valuable strategy for tunable delivery, setting the foundation for the next generation of drug delivery systems.

Overcoming Cancer Cell Drug Resistance by a Folic Acid Targeted Polymeric Conjugate of Buthionine Sulfoximine

Background:

Glutathione (GSH), which is the predominant low molecular weight intracellular thiol in mammals, has multiple functions, such as those of protecting against oxidative stress and detoxifying endogenous and exogenous electrophiles. High GSH levels, which have been observed in various types of tumors, have been thought to contribute to the resistance of neoplastic cells to apoptotic stimuli triggered by pro-oxidant therapy. Although L-(S,R)-Buthionine Sulfoximine (BSO), a selective irreversible inhibitor of glutamate cysteine ligase, depletes GSH in vitro and in in vivo and sensitizes tumor cells to radiation and some cancer chemotherapeutics, its toxicity and short in vivo half-life have limited its application to combination anticancer therapies.

Objective:

To demonstrate that a folate-targeted PEGylated BSO conjugate can sensitize cancer cells to a Reactive Oxygen Species (ROS)-generating anticancer agent by depleting GSH.

Methods:

A novel folate-targeted PEGylated-BSO conjugate was synthesized and tested in combination with gemcitabine in human cell lines that over-express (HeLa) or do not express (A549) the folate receptor.

Results:

The prepared folate-PEG-GFLG-BSO conjugate proved to be efficacious in reducing GSH levels and, when used in combination with the pro-oxidant drug gemcitabine, it enhanced drug activity in the cell line overexpressing the folate receptor.

Conclusion:

The folate-PEG-GFLG-BSO conjugate studied was found to be effective in sensitizing folatereceptor positive cancer cells to the ROS-generating drug gemcitabine.

Mathematical Models as Tools to Predict the Release Kinetic of Fluorescein from Lyotropic Colloidal Liquid Crystals

In this study, we investigated the release kinetic of fluorescein from colloidal liquid crystals made from monoglyceride and different non-ionic surfactants. The crystals were physicochemically characterized and the release experiments were carried out under the sink conditions, while mathematical models were described as extrapolations from solutions of the diffusion equation, in different initial and boundary conditions imposed by pharmaceutical formulations. The diffusion equation was solved using Laplace and Fourier transformed functions for release kinetics from infinite reservoirs in a semi-infinite medium. Solutions represents a general square root law and can be applied for the release kinetic of fluorescein from lyotropic colloidal liquid crystals. Akaike, Schwartz, and Imbimbo criteria were used to establish the appropriate mathematical model and the hierarchy of the performances of different models applied to the release experiments. The Fisher statistic test was applied to obtain the significance of differences among mathematical models. Differences of mathematical criteria demonstrated that small or no significant statistic differences were carried out between the various applied models and colloidal formulations. Phenomenological models were preferred over the empirical and semi-empirical ones. The general square root model shows that the diffusion-controlled release of fluorescein is the mathematical models extrapolated for lyotropic colloidal liquid crystals.

Effects of Silymarin-Loaded Nanoparticles on HT-29 Human Colon Cancer Cells

Background and objective: Previous studies have demonstrated the anti-cancer effects of silymarin (SLM). However, the low bioavailability of SLM has restricted its use. This study investigated the toxic effect of nanostructured SLM encapsulated in micelles (Nano-SLM) on the growth of the HT-29 human colon cancer cell line. Materials and methods: HT-29 cells were treated with 25 μM/mL of SLM or Nano-SLM for 48 h. MTT and colony formation assays were used to assess the cytotoxicity and proliferation of HT-29 cells, respectively. The cells were stained with annexin V/PI for assessment of apoptosis. Results: MTT assays revealed that Nano-SLM treatment was able to exert a more pronounced toxic effect on the HT-29 cells as compared to free SLM treatment (p < 0.01). In the Nano-SLM-treated cells, colony numbers were significantly reduced in comparison to the free SLM-treated cells (p < 0.01). Apoptotic and necrotic indexes of Nano-SLM-treated HT-29 cells were also significantly increased in comparison to those of the free SLM-treated cells (p < 0.01). The viability, proliferation and apoptosis of healthy cells (NIH-3T3 cells) were not changed in response to Nano-SLM or SLM. Conclusions: Our results indicate that Nano-SLM enhances the anti-cancer effects of SLM against human colon cancer cells.

Microchannel system for rate-controlled, sequential, and pH-responsive drug delivery

Controlled delivery of drug at a constant rate, in a sequential order, or responsive to environment conditions has been pursued for a long time to enhance the efficacy of therapeutic molecules and to minimize side effects of highly potent drugs. However, achieving such delicately-controlled delivery of a drug molecule is non-trivial and still remains a challenge. We propose the use of microchannels to control the rate, sequence, and pH-responsiveness of drug delivery for high precision and predictability. In this study, we introduce elementary drug delivery units consisting of micro-reservoirs and microchannels that have variations in their lengths, widths, numbers, and straightness. The release study demonstrates that the release rates of model drugs can be modulated by the design of microchannels. Finite element modeling of drug release predicts the performance of the drug delivery units with high accuracy. The possibility of sequential drug delivery is also demonstrated using biodegradable polymer plug in microchannels. Finally, pH-responsive delivery of drugs in microfluidic units is also discussed and demonstrated via cell viability tests.

STATEMENT OF SIGNIFICANCE

In this work, we developed microchannel-based drug delivery devices whose release rate could be accurately calculated and controlled by design of microchannel geometry. Although there have been many advances in microfabricated drug delivery systems, in particular, reservoir-based systems, no systematic investigation has been made to utilize the release channels. In our work, an equivalent electrical circuit concept was applied to the microfluidic systems for more detailed design and analysis. A microfluidic channel was regarded as an electrical resistor; their diffusion/electrical flux could be tuned with geometric factors such as length, width, a number of channel/resistor and their connections. Furthermore, from delivery rate control using channel geometry, multifunctional channel-based release systems for sequential and pH-responsive were demonstrated.

Remote magnetic switch off microgate for nanofluidic drug delivery implants

In numerous pathologies, implantable drug delivery devices provide advantages over conventional oral or parenteral approaches. Based on the site of implantation and release characteristics, implants can afford either systemic delivery or local administration, whereby the drug is delivered at or near the site of intended action. Unfortunately, current implantable drug delivery systems provide limited options for intervention in the case of an adverse reaction to the drug or the need for dosage adjustment. In the event that drug delivery must be terminated, an urgent surgical retrieval may be the only reliable option. This could be a time sensitive and costly effort, requiring access to trained professionals and emergency medical facilities. To address such limitations, here we demonstrate, in vitro and ex vivo, a novel microsystem for the rapid and effective switch off of drug delivery from an implantable nanofluidic system, by applying a safe external electromagnetic field in the FDA approved dose range. This study represents a proof of concept for a technology with potential for broad applicability to reservoir-based delivery implants for both complete interruption or remote titration of drug administration.

A Drug Carrier for Sustained Zero-Order Release of Peptide Therapeutics

Peptides have great potential as therapeutic agents, however, their clinic applications are severely hampered by their instability and short circulation half-life. Zero-order release carriers could not only extend the circulation lifetime of peptides, but also maintain the plasma drug level constant, and thus maximize their therapeutic efficacy and minimize their toxic effect. Here using PEGylated salmon calcitonin (PEG-sCT)/tannic acid (TA) film as an example, we demonstrated that hydrogen-bonded layer-by-layer films of a PEGylated peptide and a polyphenol could be a platform for zero-order peptide release. The films were fabricated under mild conditions. The second component, TA, is a natural product and presents potential therapeutic activities itself. Unlike common carriers, the new carrier releases the peptide via gradual disintegration of the film because of its dynamic nature. The release of PEG-sCT follows a perfect zero-order kinetics without initial burst release. In addition the release rate could be tuned via external stimuli, such as pH and temperature. When implanted in rats, the films could remain the plasma level of PEG-sCT constant over an extended period. Accordingly, the serum calcium level was reduced and maintained constant over the same period, suggesting an improved therapeutic efficacy of the released drug.

The Emerging Role of Nanotechnology in Cell and Organ Transplantation

Transplantation is often the only choice many patients have when suffering from end-stage organ failure. Although the quality of life improves after transplantation, challenges, such as organ shortages, necessary immunosuppression with associated complications, and chronic graft rejection, limit its wide clinical application. Nanotechnology has emerged in the past 2 decades as a field with the potential to satisfy clinical needs in the area of targeted and sustained drug delivery, noninvasive imaging, and tissue engineering. In this article, we provide an overview of popular nanotechnologies and a summary of the current and potential uses of nanotechnology in cell and organ transplantation.

IN VITRO RELEASE KINETICS MODEL FITTING OF LIPOSOMES: AN INSIGHT

Liposomes are emerging cargoes for bioactive delivery owing to their widely accepted biocompatible and biodegradable nature. It is always a challenge to control the release of payload for effective delivery to the site of interest. Over the couple of decennia, mathematical modeling of release process is a need of time whether the drug remains in the circulation or reaches at the target site. For establishing a better in vitro - in vivo correlation, release kinetics models viz. Peppas, Higuchi, Weibull, Zero Order and First order including mechanistic models like All-or-None, Toroidal, and Biomembrane models etc. are continuously exploited to predict drug release profile. Most of these models rely on the diffusion equations based on the composition of liposomes and conditions of release. Here, we summarized the crucial reports exploring these models and associated interventions to know the underlying physicochemical release phenomenon. Such mathematical model fitting can be a promising approach to deduce release/delivery process to help in designing the safe and efficacious ("Smart") liposomes.

Three-dimensional printed polymeric system to encapsulate human mesenchymal stem cells differentiated into islet-like insulin-producing aggregates for diabetes treatment

Diabetes is one of the most prevalent, costly, and debilitating diseases in the world. Pancreas and islet transplants have shown success in re-establishing glucose control and reversing diabetic complications. However, both are limited by donor availability, need for continuous immunosuppression, loss of transplanted tissue due to dispersion, and lack of vascularization. To overcome the limitations of poor islet availability, here, we investigate the potential of bone marrow–derived mesenchymal stem cells differentiated into islet-like insulin-producing aggregates. Islet-like insulin-producing aggregates, characterized by gene expression, are shown to be similar to pancreatic islets and display positive immunostaining for insulin and glucagon. To address the limits of current encapsulation systems, we developed a novel three-dimensional printed, scalable, and potentially refillable polymeric construct (nanogland) to support islet-like insulin-producing aggregates’ survival and function in the host body. In vitro studies showed that encapsulated islet-like insulin-producing aggregates maintained viability and function, producing steady levels of insulin for at least 4 weeks. Nanogland—islet-like insulin-producing aggregate technology here investigated as a proof of concept holds potential as an effective and innovative approach for diabetes cell therapy.

Zero-order release of polyphenolic drugs from dynamic, hydrogen-bonded LBL films

Drug carriers capable of releasing drugs at a constant rate, or following zero-order kinetics, can lead to the best control of plasma drug concentration. Here we demonstrated that zero-order release of polyphenolic drugs, including tannic acid, epigallocatechin gallate, proanthocyanidins, and theaflavin-3'-gallate, could be achieved using hydrogen-bonded layer-by-layer films as the drug carrier. The films were fabricated using the polyphenolic drugs as hydrogen donors and polyethylene glycol (PEG) as the hydrogen acceptor. Because the drugs and PEG are bonded with reversible, dynamic hydrogen bonds, the films disintegrate gradually in aqueous solutions, and thus release the drugs into the media. Furthermore, because the PEG polymers have a narrow molecular weight distribution, the films disintegrate and release the polyphenolic drugs at a constant rate. Besides allowing for zero-order release, the drug carrier developed here also provides various ways to tune the drug release rate. The drug release rate increases with decreasing molecular weight of PEG. More importantly, the release rate could be tuned using external stimuli. Increasing the pH or temperature results in accelerated drug release, while the addition of salt retards the drug release.

Impedance characterization, degradation, and in vitro biocompatibility for platinum electrodes on BioMEMS

Fine control of molecular transport through microfluidic systems can be obtained by modulation of an applied electrical field across channels with the use of electrodes. In BioMEMS designed for biological fluids and in vivo applications, electrodes must be biocompatible, biorobust and stable. In this work, the analysis and characterization of platinum (Pt) electrodes integrated on silicon substrates for biomedical applications are presented. Electrodes were incorporated on the surface of silicon chips by adhesion of laminated Pt foils or deposited at 30°, 45° or 90° angle by e-beam or physical vapor (sputtering) methods. Electrical and physical properties of the electrodes were quantified and evaluated using electrical impedance spectroscopy and modelling of the electrode-electrolyte interfaces. Electrode degradation in saline solution at pH 7.4 was tested at room temperature and under accelerated conditions (90 °C), both in the presence and absence of an applied electrical potential. Degradation was quantified using atomic force microscopy (AFM) and inductively coupled plasma mass spectroscopy (ICP-MS). Biocompatibility was assessed by MTT proliferation assay with human dermal fibroblasts. Results demonstrated that the deposited electrodes were biocompatible with negligible material degradation and exhibited electrochemical behavior similar to Pt foils, especially for e-beam deposited electrodes. Finally, Pt electrodes e-beam deposited on silicon nanofabricated nanochannel membranes were evaluated for controlled drug delivery applications. By tuning a low applied electrical potential (<1.5 VDC) to the electrodes, temporal modulation of the dendritic fullerene 1 (DF-1) release from a source reservoir was successfully achieved as a proof of concept, highlighting the potential of deposited electrodes in biomedical applications.

Sustained Administration of Hormones Exploiting Nanoconfined Diffusion through Nanochannel Membranes

Implantable devices may provide a superior means for hormone delivery through maintaining serum levels within target therapeutic windows. Zero-order administration has been shown to reach an equilibrium with metabolic clearance, resulting in a constant serum concentration and bioavailability of released hormones. By exploiting surface-to-molecule interaction within nanochannel membranes, it is possible to achieve a long-term, constant diffusive release of agents from implantable reservoirs. In this study, we sought to demonstrate the controlled release of model hormones from a novel nanochannel system. We investigated the delivery of hormones through our nanochannel membrane over a period of 40 days. Levothyroxine, osteocalcin and testosterone were selected as representative hormones based on their different molecular properties and structures. The release mechanisms and transport behaviors of these hormones within 3, 5 and 40 nm channels were characterized. Results further supported the suitability of the nanochannels for sustained administration from implantable platforms.

Mild hyperthermia enhances transport of liposomal gemcitabine and improves in vivo therapeutic response

Obstructive biological barriers limit the transport and efficacy of cancer nanotherapeutics. Creative manipulation of tumor microenvironment provides promising avenues towards improving chemotherapeutic response. Such strategies include the use of mechanical stimuli to overcome barriers, and increase drug delivery and therapeutic efficacy. The rational use of gold nanorod-mediated mild hyperthermia treatment (MHT) alters tumor transport properties, increases liposomal gemcitabine (Gem Lip) delivery, and antitumor efficacy in pancreatic cancer CAPAN-1 tumor model. MHT treatment leads to a threefold increase in accumulation of 80-nm liposomes and enhances spatial interstitial distribution. I.v. injection of Gem Lip and MHT treatment lead to a threefold increase in intratumor gemcitabine concentration compared to chemotherapeutic infusion alone. Furthermore, combination of MHT treatment with infusion of 12 mg kg(-1) Gem Lip leads to a twofold increase in therapeutic efficacy and inhibition of CAPAN-1 tumor growth when compared to equimolar chemotherapeutic treatment alone. Enhanced therapeutic effect is confirmed by reduction in tumor size and increase in apoptotic index where MHT treatment combined with 12 mg kg(-1) Gem Lip achieves similar therapeutic efficacy as the use of 60 mg kg(-1) free gemcitabine. In conclusion, improvements in vivo efficacy are demonstrated resulting from MHT treatment that overcome transport barriers, promote delivery, improve efficacy of nanomedicines.

Leveraging electrokinetics for the active control of dendritic fullerene-1 release across a nanochannel membrane

General adoption of advanced treatment protocols such as chronotherapy will hinge on progress in drug delivery technologies that provide precise temporal control of therapeutic release. Such innovation is also crucial to future medicine approaches such as telemedicine. Here we present a nanofluidic membrane technology capable of achieving active and tunable control of molecular transport through nanofluidic channels. Control was achieved through application of an electric field between two platinum electrodes positioned on either surface of a 5.7 nm nanochannel membrane designed for zero-order drug delivery. Two electrode configurations were tested: laser-cut foils and electron beam deposited thin-films, configurations capable of operating at low voltage (≤1.5 V), and power (100 nW). Temporal, reproducible tuning and interruption of dendritic fullerene 1 (DF-1) transport was demonstrated over multi-day release experiments. Conductance tests showed limiting currents in the low applied potential range, implying ionic concentration polarization (ICP) at the interface between the membrane's micro- and nanochannels, even in concentrated solutions (≤1 M NaCl). The ability of this nanotechnology platform to facilitate controlled delivery of molecules and particles has broad applicability to next-generation therapeutics for numerous pathologies, including autoimmune diseases, circadian dysfunction, pain, and stress, among others.

Delivering enhanced testosterone replacement therapy through nanochannels

Primary or secondary hypogonadism results in a range of signs and symptoms that compromise quality of life and requires life-long testosterone replacement therapy. In this study, an implantable nanochannel system is investigated as an alternative delivery strategy for the long-term sustained and constant release of testosterone. In vitro release tests are performed using a dissolution set up, with testosterone and testosterone:2-hydroxypropyl-β-cyclodextrin (TES:HPCD) 1:1 and 1:2 molar ratio complexes release from the implantable nanochannel system and quantify by HPLC. 1:2 TES:HPCD complex stably achieve 10-15 times higher testosterone solubility with 25-30 times higher in vitro release. Bioactivity of delivered testosterone is verified by LNCaP/LUC cell luminescence. In vivo evaluation of testosterone, luteinizing hormone (LH), and follicle stimulating hormone (FSH) levels by liquid chromatography mass spectrometry (LC/MS) and multiplex assay is performed in castrated Sprague-Dawley rats over 30 d. Animals are treated with the nanochannel implants or degradable testosterone pellets. The 1:2 TES:HPCD nanochannel implant exhibits sustained and clinically relevant in vivo release kinetics and attains physiologically stable plasma levels of testosterone, LH, and FSH. In conclusion, it is demonstrated that by providing long-term steady release 1:2 TES:HPCD nanochannel implants may represent a major breakthrough for the treatment of male hypogonadism.

Long Term Stability Evaluation of Prostacyclin Released from Biomedical Device through Turbiscan Lab Expert

Therapeutic guidelines indicate prostacyclin as the first line of treatment in inflammation and vascular diseases. Prostacyclins prevent formation of the platelet plug involved in primary hemostasis by inhibiting platelet activation and, combined with thromboxane, are effective vasodilators in vascular damage. Trans-Atlantic Inter-Society Consensus Document on Management of Peripheral Arterial Disease II guidelines indicates prostacyclins; in particular, Iloprost, as the first therapeutic option for treating peripheral arterial disease. However, therapeutic efficacy of Iloprost has witnessed several drawbacks that have occurred in patients receiving repeated weekly administration of the drug by intravenous infusions. Adverse reactions arose under perfusion with Iloprost for 6 h and patient compliance was drastically decreased. Biomedical devices could provide a suitable alternative to overcome these drawbacks. In particular, elastomeric pumps, filled with Iloprost isotonic solution, could slowly release the drug, thus decreasing its side effects, representing a valid alternative to hospitalization of patients affected by peripheral arterial disease. However, the home therapy treatment of patients requires long-term stability of Iloprost in solution-loaded elastomeric pumps. The aim of this work was to investigate the long-term stability of Iloprost isotonic solution in biomedical devices using Turbiscan technology. Turbiscan Lab Expert (L'Union, France) predicts the long-term stability of suspensions, emulsions and colloidal formulations by measuring backscattering and transmission of particulates dispersed in solution. The formulations were evaluated by measuring the variation of physical-chemical properties of colloids and suspensions as a function of backscattering and transmission modifications. In addition, the release profile of Iloprost isotonic solution from the biomedical device was evaluated.

Electrospun nanofibers-mediated on-demand drug release

A living system has a complex and accurate regulation system with intelligent sensor-processor-effector components to enable the release of vital bioactive substances on demand at a specific site and time. Stimuli-responsive polymers mimic biological systems in a crude way where an external stimulus results in a change in conformation, solubility, or alternation of the hydrophilic/hydrophobic balance, and consequently release of a bioactive substance. Electrospinning is a straightforward and robust method to produce nanofibers with the potential to incorporate drugs in a simple, rapid, and reproducible process. This feature article emphasizes an emerging area using an electrospinning technique to generate biomimetic nanofibers as drug delivery devices that are responsive to different stimuli, such as temperature, pH, light, and electric/magnetic field for controlled release of therapeutic substances. Although at its infancy, the mimicry of these stimuli-responsive nanofibers to the function of the living systems includes both the fibrous structural feature and bio-regulation function as an on demand drug release depot. The electrospun nanofibers with extracellular matrix morphology intrinsically guide cellular drug uptake, which will be highly desired to translate the promise of drug delivery for the clinical success.

Targeting the thyroid gland with thyroid-stimulating hormone (TSH)-nanoliposomes

Various tissue-specific antibodies have been attached to nanoparticles to obtain targeted delivery. In particular, nanodelivery systems with selectivity for breast, prostate and cancer tissue have been developed. Here, we have developed a nanodelivery system that targets the thyroid gland. Nanoliposomes have been conjugated to the thyroid-stimulating hormone (TSH), which binds to the TSH receptor (TSHr) on the surface of thyrocytes. The results indicate that the intracellular uptake of TSH-nanoliposomes is increased in cells expressing the TSHr. The accumulation of targeted nanoliposomes in the thyroid gland following intravenous injection was 3.5-fold higher in comparison to untargeted nanoliposomes. Furthermore, TSH-nanoliposomes encapsulated with gemcitabine showed improved anticancer efficacy in vitro and in a tumor model of follicular thyroid carcinoma. This drug delivery system could be used for the treatment of a broad spectrum of thyroid diseases to reduce side effects and improve therapeutic efficacy.