Drug delivery systems for differential release in combination therapy

Release kinetics of growth factors loaded into β-TCP ceramics in an in vitro model

Introduction

β-TCP ceramics are bone replacement materials that have recently been tested as a drug delivery system that can potentially be applied to endogenous substances like growth factors found in blood platelets to facilitate positive attributes.

Methods

In this work, we used flow chamber loading to load β-TCP dowels with blood suspensions of platelet-rich plasma (PRP), platelet-poor plasma (PPP), or buffy coat (BC) character. PRP and BC platelet counts were adjusted to the same level by dilution. Concentrations of TGF-β1, PDGF-AB, and IGF-1 from dowel-surrounding culture medium were subsequently determined using ELISA over 5 days. The influence of alginate was additionally tested to modify the release.

Results

Concentrations of TGF-β1 and PDGF-AB increased and conclusively showed a release from platelets in PRP and BC compared to PPP. The alginate coating reduced the PDGF-AB release but did not reduce TGF-β1 and instead even increased TGF-β1 in the BC samples. IGF-1 concentrations were highest in PPP, suggesting circulating levels rather than platelet release as the driving factor. Alginate samples tended to have lower IGF-1 concentrations, but the difference was not shown to be significant.

Discussion

The release of growth factors from different blood suspensions was successfully demonstrated for β-TCP as a drug delivery system with release patterns that correspond to PRP activation after Ca2+-triggered activation. The release pattern was partially modified by alginate coating.

Magnetic Miniature Soft Robot with Reprogrammable Drug-Dispensing Functionalities: Toward Advanced Targeted Combination Therapy

Miniature robots are untethered actuators, which have great prospects to transform targeted drug delivery because they can potentially deliver high concentrations of medicine to the disease site(s) with minimal complications. However, existing miniature robots cannot perform advanced targeted combination therapy; majority of them can at most transport one type of drug, while those that can carry multiple drugs are unable to change their drug-dispensing sequence and dosage. Furthermore, the latter robots cannot transport more than three types of drugs, selectively dispense their drugs, maintain their mobility, or release their drugs at multiple sites. Here, a millimeter-scale soft robot is proposed, which can be actuated by alternating magnetic fields to dispense four types of drugs with reprogrammable drug-dispensing sequence and dosage (dispensing rates: 0.0992-0.231 µL h-1). This robot has six degrees-of-freedom motions, and it can deliver its drugs to multiple desired sites by rolling and two-anchor crawling across unstructured environments with negligible drug leakage. Such dexterity is highly desirable and unprecedented for miniature robots with drug-dispensing capabilities. The soft robot therefore has great potential to enable advanced targeted combination therapy, where four types of drugs must be delivered to various disease sites, each with a specific sequence and dosage of drugs.

Use of Drug Sensitisers to Improve Therapeutic Index in Cancer

The clinical management of malignant tumours is challenging, often leading to severe adverse effects and death. Drug resistance (DR) antagonises the effectiveness of treatments, and increasing drug dosage can worsen the therapeutic index (TI). Current efforts to overcome DR predominantly involve the use of drug combinations, including applying multiple anti-cancerous drugs, employing drug sensitisers, which are chemical agents that enhance pharmacokinetics (PK), including the targeting of cellular pathways and regulating pertinent membrane transporters. While combining multiple compounds may lead to drug-drug interactions (DDI) or polypharmacy effect, the use of drug sensitisers permits rapid attainment of effective treatment dosages at the disease site to prevent early DR and minimise side effects and will reduce the chance of DDI as lower drug doses are required. This review highlights the essential use of TI in evaluating drug dosage for cancer treatment and discusses the lack of a unified standard for TI within the field. Commonly used benefit-risk assessment criteria are summarised, and the critical exploration of the current use of TI in the pharmaceutical industrial sector is included. Specifically, this review leads to the discussion of drug sensitisers to facilitate improved ratios of effective dose to toxic dose directly in humans. The combination of drug and sensitiser molecules might see additional benefits to rekindle those drugs that failed late-stage clinical trials by the removal of detrimental off-target activities through the use of lower drug doses. Drug combinations and employing drug sensitisers are potential means to combat DR. The evolution of drug combinations and polypharmacy on TI are reviewed. Notably, the novel binary weapon approach is introduced as a new opportunity to improve TI. This review emphasises the urgent need for a criterion to systematically evaluate drug safety and efficiency for practical implementation in the field.

Genetic insights and therapeutic potential for colorectal cancer: mutation analysis of KRAS gene and efficacy of Oleuropein-conjugated iron oxide nanoparticles

This study aimed to address the challenges of treating advanced stages of colon cancer (CRC) by exploring potential therapeutic options. The research focused on the genetic aspects of CRC, specifically the mutation rate of the KRAS gene, along with other genes like TTN, APC, MUC16, and TP53, using the TCGA dataset. Additionally, the study investigated the efficacy of Oleuropein, a polyphenolic compound found in olives, in combating CRC by using iron oxide nanoparticles coated with glucose and conjugated with Oleuropein. The study characterized the physicochemical properties of the nanoparticles, and the cytotoxic effects of the nanoparticles were evaluated on CRC and normal fibroblast cell lines, demonstrating significantly higher cytotoxicity against CRC cells compared to normal cells. Furthermore, the study analyzed gene expression changes using the GSE124627 dataset to understand the influence of KRAS alterations. It identified numerous upregulated and downregulated genes in KRAS-overexpressing samples, suggesting their involvement in critical cancer-related pathways. These findings suggest that KRAS-influenced genes could serve as potential therapeutic targets for CRC treatment. The study also examined the expression levels of identified genes in CRC samples compared to normal samples. Among the upregulated genes, 22 showed significant increases in cancer samples, while 14 downregulated genes exhibited decreased expression in both KRAS-influenced and cancer samples. Cox regression analysis identified specific upregulated genes, including ANKZF1, SNAI1, PPFIA4, SIX4, and NOTUM, associated with poor prognosis. Kaplan-Meier analysis further confirmed the correlation between increased expression of these genes and higher patient mortality rates. In conclusion, this study provided valuable insights into the genetic aspects of CRC and potential therapeutic strategies. The use of Oleuropein-conjugated iron oxide nanoparticles showed promising cytotoxic effects on colon cancer cells. These findings contribute to advancing our understanding of CRC and offer potential targets for further investigation and the development of novel therapeutic approaches.

Harness arsenic in medicine: current status of arsenicals and recent advances in drug delivery

INTRODUCTION

Arsenicals have a special place in the history of human health, acting both as poison and medicine. Having been used to treat a variety of diseases in the past, the success of arsenic trioxide (ATO) in treating acute promyelocytic leukemia (APL) in the last century marked its use as a drug in modern medicine. To expand their role against cancer, there have been clinical uses of arsenicals worldwide and progress in the development of drug delivery for various malignancies, especially solid tumors.

AREAS COVERED

In this review, conducted on Google Scholar [1977-2024], we start with various forms of arsenicals, highlighting the well-known ATO. The mechanism of action of arsenicals in cancer therapy is then overviewed. A summary of the research progress in developing new delivery approaches (e.g. polymers, inorganic frameworks, and biomacromolecules) in recent years is provided, addressing the challenges and opportunities in treating various malignant tumors.

EXPERT OPINION

Reducing toxicity and enhancing therapeutic efficacy are guidelines for designing and developing new arsenicals and drug delivery systems. They have shown potential in the fight against cancer and emerging pathogens. New technologies and strategies can help us harness the potency of arsenicals and make better products.

Tailoring Biomaterials Ameliorate Inflammatory Bone Loss

Inflammatory diseases, such as rheumatoid arthritis, periodontitis, chronic obstructive pulmonary disease, and celiac disease, disrupt the delicate balance between bone resorption and formation, leading to inflammatory bone loss. Conventional approaches to tackle this issue encompass pharmaceutical interventions and surgical procedures. Nevertheless, pharmaceutical interventions exhibit limited efficacy, while surgical treatments impose trauma and significant financial burden upon patients. Biomaterials show outstanding spatiotemporal controllability, possess a remarkable specific surface area, and demonstrate exceptional reactivity. In the present era, the advancement of emerging biomaterials has bestowed upon more efficacious solutions for combatting the detrimental consequences of inflammatory bone loss. In this review, the advances of biomaterials for ameliorating inflammatory bone loss are listed. Additionally, the advantages and disadvantages of various biomaterials-mediated strategies are summarized. Finally, the challenges and perspectives of biomaterials are analyzed. This review aims to provide new possibilities for developing more advanced biomaterials toward inflammatory bone loss.

Establishment of bone-targeted nano-platform and the study of its combination with 2-deoxy-d-glucose enhanced photodynamic therapy to inhibit bone metastasis

At present, simple anti-tumor drugs are ineffective at targeting bone tissue and are not purposed to treat patients with bone metastasis. In this study, zoledronic acid (ZOL) demonstrated excellent bone-targeting properties as a bone-targeting ligand. The metal-organic framework (MOF) known as ZIF-90 was modified with ZOL to construct a bone-targeting-based drug delivery system. Chlorin e6 (Ce6) was loaded in the bone-targeted drug delivery system and combined with 2-deoxy-D-glucose (2-DG), which successfully treated bone tumors when enhanced photodynamic therapy was applied. The Ce6@ZIF-PEG-ZOL (Ce6@ZPZ) nanoparticles were observed to have uniform morphology, a particle size of approximately 210 nm, and a potential of approximately -30.4 mV. The results of the bone-targeting experiments showed that Ce6@ZPZ exhibited a superior bone-targeted effect when compared to Ce6@ZIF-90-PEG. The Ce6@ZPZ solution was subjected to 660 nm irradiation and the resulting production of reactive oxygen species increased over time, which could be further increased when Ce6@ZPZ was used in combination with 2-DG. Their combination had a stronger inhibitory capacity against tumor cells than either 2-DG or Ce6@ZPZ alone, increasing the rate of tumor cell apoptosis. The apoptosis rate caused by HGC-27 was 61.56% when 2-DG was combined with Ce6@ZPZ. In vivo results also showed that Ce6@ZPZ combined with 2-DG maximally inhibited tumor growth and prolonged mice survival compared to the other experimental groups. Therefore, the combination of PDT and glycolytic inhibitors serves as a potential option for the treatment of cancer.

The anti-spermatogenic activity of nanoliposomes loaded with Heracleum persicum phenolic compounds in Balb/C mice

There are various types of bioactivities that have been reported for Heracleum persicum species, such as antioxidant, anti-inflammatory, and cytotoxicity properties. In the current study, the bio-accessibility of H. persicum bioactive compounds was improved by purifying its phenolic-enriched fractions (PEF) and encapsulating them into nanoliposomes to analyze its cytotoxic impacts on mice testicular tissue and their fertility status. Nano liposomal H. persicum PEF (NL-HPEF) was prepared by ultrasound-based encapsulation of HPEF and L-agranular lecithin mixture. The size, morphology, and stability of NL-HPEF were characterized by dynamic light scattering, field emission scanning electron microscopy, and zeta potential analysis. The 18 white male Balb/c mice (20-25 g) at 3 treatment groups were provided to study the NL-HPPF cytotoxicity by measuring the mice liver enzyme including aspartate aminotransferase (AST), ALP and alanine aminotransferase (ALT), testis lipid peroxidation, and testicular tissue destruction levels. Moreover, the mice's fertility was evaluated by studying the Adam3, Prm1, Spata19, and Tnp2 gene expression in the testicular tissues. The obtained results manifested that the synthesized NL-HPEF was stable (193.7 nm) and exhibited a notable cytotoxic impact on the mice's liver (ALT and AST enhancement levels) and testicular tissues. Moreover, their increasing treatment doses impaired the male mice's fertility by decreasing the sperm count, viability, and motility. In addition, fertility suppression was verified by decreasing serum testosterone and downregulating the Adam3, Prm1, Spata19, and Tnp2 gene expression in their testicular tissues. The male mice's fertility was significantly (p < 0.05) suppressed by increasing treatment doses of NL-HPEF. Hence, the NL-HPEF could be considered a promising alternative to replace the male chemical contraceptives drugs.

Liposome-Based Antibacterial Delivery: An Emergent Approach to Combat Bacterial Infections

The continued emergence and spread of drug-resistant pathogens and the decline in the approval of new antimicrobial drugs pose a major threat to managing infectious diseases, resulting in high morbidity and mortality. Even though a significant variety of antibiotics can effectively cure many bacterial infectious diseases, microbial infections remain one of the biggest global health problems, which may be due to the traditional drug delivery system's shortcomings which lead to poor therapeutic index, low drug absorption, and numerous other drawbacks. Further, the use of traditional antibiotics to treat infectious diseases has always been accompanied by the emergence of multidrug resistance and adverse side effects. Despite developing numerous new antibiotics, nanomaterials, and various techniques to combat infectious diseases, they have persisted as major global health issues. Improving the current antibiotic delivery systems is a promising approach to solving many life-threatening infections. In this context, nanoliposomal systems have recently attracted much attention. Herein, we attempt to provide a concise summary of recent studies that have used liposomal nanoparticles as delivery systems for antibacterial medicines. The minireview also highlights the enormous potential of liposomal nanoparticles as antibiotic delivery systems. The future of these promising approaches lies in developing more efficient delivery systems by precisely targeting bacterial cells with antibiotics with minimum cytotoxicity and high bacterial combating efficacy.

Therapeutic applications of nanobiotechnology

Nanobiotechnology, as a novel and more specialized branch of science, has provided a number of nanostructures such as nanoparticles, by utilizing the methods, techniques, and protocols of other branches of science. Due to the unique features and physiobiological characteristics, these nanostructures or nanocarriers have provided vast methods and therapeutic techniques, against microbial infections and cancers and for tissue regeneration, tissue engineering, and immunotherapies, and for gene therapies, through drug delivery systems. However, reduced carrying capacity, abrupt and non-targeted delivery, and solubility of therapeutic agents, can affect the therapeutic applications of these biotechnological products. In this article, we explored and discussed the prominent nanobiotechnological methods and products such as nanocarriers, highlighted the features and challenges associated with these products, and attempted to conclude if available nanostructures offer any scope of improvement or enhancement. We aimed to identify and emphasize the nanobiotechnological methods and products, with greater prospect and capacity for therapeutic improvements and enhancements. We found that novel nanocarriers and nanostructures, such as nanocomposites, micelles, hydrogels, microneedles, and artificial cells, can address the associated challenges and inherited drawbacks, with help of conjugations, sustained and stimuli-responsive release, ligand binding, and targeted delivery. We recommend that nanobiotechnology, despite having few challenges and drawbacks, offers immense opportunities that can be harnessed in delivering quality therapeutics with precision and prediction. We also recommend that, by exploring the branched domains more rigorously, bottlenecks and obstacles can also be addressed and resolved in return.

Dual-Drug Delivery by Anisotropic and Uniform Hybrid Nanostructures: A Comparative Study of the Function and Substrate-Drug Interaction Properties

By utilizing nanoparticles to upload and interact with several pharmaceuticals in varying methods, the primary obstacles associated with loading two or more medications or cargos with different characteristics may be addressed. Therefore, it is feasible to evaluate the benefits provided by co-delivery systems utilizing nanoparticles by investigating the properties and functions of the commonly used structures, such as multi- or simultaneous-stage controlled release, synergic effect, enhanced targetability, and internalization. However, due to the unique surface or core features of each hybrid design, the eventual drug-carrier interactions, release, and penetration processes may vary. Our review article focused on the drug's loading, binding interactions, release, physiochemical, and surface functionalization features, as well as the varying internalization and cytotoxicity of each structure that may aid in the selection of an appropriate design. This was achieved by comparing the actions of uniform-surfaced hybrid particles (such as core-shell particles) to those of anisotropic, asymmetrical hybrid particles (such as Janus, multicompartment, or patchy particles). Information is provided on the use of homogeneous or heterogeneous particles with specified characteristics for the simultaneous delivery of various cargos, possibly enhancing the efficacy of treatment techniques for illnesses such as cancer.

Xanthan-Based Materials as a Platform for Heparin Delivery

Heparin (Hep), with its anticoagulant activity, antiangiogenic and apoptotic effects, and growth factor binding, plays an important role in various biological processes. Formulations as drug delivery systems protect its biological activity, and limit the potential side effects of faulty administration. The objective of this study was to develop novel xanthan-based materials as a delivery carrier for heparin. The materials exhibited remarkable elastic behavior and toughness without any crack development within the network, which also support their application for tissue engineering. It was found that all materials possessed the ability to control the release of heparin, according to the Korsmeyer-Peppas release model. All Hep-containing materials caused significant exchanges of the activated partial thromboplastin time (aPTT) and prothrombin time (PT) parameters, indicating that formulated natural/natural synthetic polymeric networks conserved heparin's biological activity and its ability to interrupt the blood coagulation cascade. The obtained results confirmed that developed materials could be carriers for the controlled release of heparin, with potential applications in topical administration.

Microfluidic Nanoparticles for Drug Delivery

Nanoparticles (NPs) have attracted tremendous interest in drug delivery in the past decades. Microfluidics offers a promising strategy for making NPs for drug delivery due to its capability in precisely controlling NP properties. The recent success of mRNA vaccines using microfluidics represents a big milestone for microfluidic NPs for pharmaceutical applications, and its rapid scaling up demonstrates the feasibility of using microfluidics for industrial-scale manufacturing. This article provides a critical review of recent progress in microfluidic NPs for drug delivery. First, the synthesis of organic NPs using microfluidics focusing on typical microfluidic methods and their applications in making popular and clinically relevant NPs, such as liposomes, lipid NPs, and polymer NPs, as well as their synthesis mechanisms are summarized. Then, the microfluidic synthesis of several representative inorganic NPs (e.g., silica, metal, metal oxide, and quantum dots), and hybrid NPs is discussed. Lastly, the applications of microfluidic NPs for various drug delivery applications are presented.

Synchronizing the release rates of topotecan and paclitaxel from a self-eroding crosslinked chitosan - PLGA platform

This study is a continuation of a previous study in which two model drugs, sodium salicylate (highly water-soluble) and indomethacin (low water-soluble) were loaded into an erodible hydrogel, made of ionically crosslinked chitosan (x-Ct). The erosion rate of the x-Ct matrix was controlled by its immersion in calcium chloride solutions (de-crosslinker) of different concentrations, leading to synchronization of the release rates of the two drugs over 2 h. In the present study, a modified platform was developed in order to (a) synchronize the release rates of the two cytotoxic drugs, topotecan (TT, highly water soluble) and paclitaxel (PTX, poorly water soluble); (b) prolong the erosion duration and the derived concomitant release of the two drugs to several days. TT was loaded into a PLGA sphere, which was co-loaded with calcium chloride (CaCl₂). The sphere was then placed in an aqueous solution of chitosan (Ct) in which PTX was dispersed. A PLGA core-containing hydrogel was then produced by ionically crosslinking the Ct. The formulation screening section of the study includes a statistically designed Fractional Factorial experiment. It was comprised of the following five experimental factors: (a) the type of Ct and (b) its relative amount in the formulation, (c) the type of ionic crosslinker (citric acid or oxalic acid), (d) the concentration of the ionic crosslinker and (e) the co-loaded amounts of CaCl₂ (the constitutional de-crosslinking agent). The difference factor, f1, and the similarity factor, f2, of the TT and PTX release profiles into water, were used as the experimental responses. The computerized prediction models were employed to assess the collective effects of the pre-determined experimental factors on the difference factor, f1, and the similarity factor, f2 (the response factors), by employing a fractional factorial design and multifactorial analysis, without the need to account for the exact mechanisms of the release processes involved. The final composite platform was capable of releasing TT and PTX, at similar (concomitant) rates, over a period of 7 days, a finding which suggests that the novel polymeric platform may serve as a multi-drug implant. An attractive medical application for such a device would be post-operative local treatment that could benefit from localized combination chemotherapy after the removal of malignant tissues, in the surgical treatment of breast cancer, ovarian cancer, glioma and peritoneal carcinomatosis.

A review on plant polysaccharide based on drug delivery system for construction and application, with emphasis on traditional Chinese medicine polysaccharide

Carbohydrate polymers with unique chemical composition, molecular weight and functional chemical groups show multiple potentials in drug delivery. Most carbohydrate polymers such as plant polysaccharides exhibit advantages of biodegradability, ease of modification, low immunogenicity and low toxicity. They can be conjugated, cross-linked or functionally modified, and then used as nanocarrier materials. Polysaccharide drug delivery system can avoid the phagocytosis of the reticuloendothelial system, prevent the degradation of biomolecules, and increase the bioavailability of small molecules, thus exerting effective therapeutic effects. Therefore, they have been fully explored. In this paper, we reviewed the construction methods of drug delivery systems based on carbohydrate polymers (astragalus polysaccharide, angelica polysaccharide, lycium barbarum polysaccharide, ganoderma lucidum polysaccharide, bletilla polysaccharide, glycyrrhiza polysaccharide, and epimedium polysaccharides, etc). The application of polysaccharide drug delivery systems to deliver small molecule chemotherapeutic drugs, gene drugs, and metal ion drugs was also briefly introduced. At the same time, the role of the polysaccharide drug delivery system in tumor treatment, targeted therapy, and wound healing was discussed. In addition, the research of polysaccharide delivery systems based on the therapeutic efficacy of traditional Chinese medicine was also summarized and prospected.

Targeted delivery of doxorubicin by Thermo/pH-responsive magnetic nanoparticles in a rat model of breast cancer

The novel folate conjugated Thermo/pH-responsive magnetic nanoparticles (folate-poly-MNPs) have been developed as a potential nanocarrier for improving site-specific drug delivery, tumor drug accumulation, and therapeutic effects while reducing the adverse effects of conventional drug delivery systems. To evaluate the anticancer efficacy of developed tumor-targeted drug delivery system, forty rat models of breast cancer received saline as control, DOX, DOX-poly-MNPs, and DOX-folate-poly-MNPs at a dose of 2 mg/kg/48 h. The DOX-folate-poly-MNPs showed a significant increase in protein expression of BAX and C-caspase-3 with concomitant downregulation of Bcl-2 expression and ki67 proliferation index compared to the DOX group. The synergistic antitumor efficacy of passive and active drug targeting led to enhanced drug uptake, increased tumor cell apoptosis, decreased tumor volume, and a prolonged survival rate in animals, suggesting that DOX-folate-poly-MNPs may prove to be a promising nanomedicine for the smart treatment of breast cancer in the future.

Rapid analytical method development and validation for the simultaneous estimation of 5-Fluorouracil and Cannabidiol in plasma and lipid-based nanoformulations

Background:

5-Fluorouracil (5-FU) is a well-established anticancer drug. Several studies have also demonstrated the anticancer potential of Cannabidiol (CBD) against various malignancies, including skin cancer. Reported synergistic effects of this combination fascinate researchers to consider this for the management of skin cancer.

Methods:

A simple and robust HPLC method for simultaneous estimation of 5-FU and CBD at its single wavelength (237 nm) was developed and validated. The separation of these compounds was performed on Waters® HPLC system with Hypersil™ C18 RP-column using methanol and water in gradient flow as mobile phase. The method could effectively quantify the nanogram levels of both analytes simultaneously in plasma spiked samples and various nanoformulations. The analytical performance of the proposed method was validated in terms of various parameters, such as linearity, ruggedness, specificity, and few others.

Results:

5-FU as well as CBD were successfully detected at 237 nm with retention time 1.4 and 1.84 minutes respectively. Calibration curves were found to be linear with R2 values of 0.985 and 0.984 for 5-FU and CBD respectively. The method was linear, precise, specific and robust. Additionally, prepared method successfully employed in determining concentration of both drugs in combitorial nanoformulations.

Conclusion:

The findings show that the developed method was simple, reliable, sensitive and economical. It could be employed for the simultaneous estimation of 5-FU and CBD in various in vitro and in vivo studies.

Targeted Delivery of Drugs and Genes Using Polymer Nanocarriers for Cancer Therapy

Cancer is one of the primary causes of worldwide human deaths. Most cancer patients receive chemotherapy and radiotherapy, but these treatments are usually only partially efficacious and lead to a variety of serious side effects. Therefore, it is necessary to develop new therapeutic strategies. The emergence of nanotechnology has had a profound impact on general clinical treatment. The application of nanotechnology has facilitated the development of nano-drug delivery systems (NDDSs) that are highly tumor selective and allow for the slow release of active anticancer drugs. In recent years, vehicles such as liposomes, dendrimers and polymer nanomaterials have been considered promising carriers for tumor-specific drug delivery, reducing toxicity and improving biocompatibility. Among them, polymer nanoparticles (NPs) are one of the most innovative methods of non-invasive drug delivery. Here, we review the application of polymer NPs in drug delivery, gene therapy, and early diagnostics for cancer therapy.

Recent Advances on Stimuli-Responsive Combination Therapy against Multidrug-Resistant Bacteria and Biofilm

The widespread occurrence of infections from multidrug-resistant (MDR) bacteria is a global health problem. It has been amplified over the past few years due to the increase in adaptive traits in bacteria and lack of advanced treatment strategies. Because of the low bioavailability and limited penetration at infected sites, the existing antibiotics often fail to resist bacterial growth. Recently, developed stimuli-responsive drug delivery systems and combinatorial therapeutic systems based on nanoparticles, metal-organic frameworks, hydrogels, and organic chromophores offer the ability to improve the therapeutic efficacy of antibiotics by reducing drug resistance and other side effects. These therapeutic systems have been designed with the relevant chemical and physical properties that respond to specific triggers resulting in spatiotemporal controlled release and site-specific transportability. This review highlights the latest development of single and dual/multistimuli-responsive antibiotic delivery systems for combination therapies to treat MDR bacterial infections and biofilm eradication.

Revolutionizing technologies of nanomicelles for combinatorial anticancer drug delivery

Insufficient efficacy of current single drug therapy of cancers have led to the advancement of combination drug-loaded formulations. Specifically, polymeric micelles have been focused on as efficient injectable vehicles for the delivery of several anticancer drugs simultaneously to cancer cells. These nano delivery systems have evolved with advancements in the area of nanotechnology. The current review presents a summary of the past events that have led to the procession of nanomicelles and novel nanotechnologies for combinatorial drug delivery. It also focuses on the advantages, disadvantages, and considerations for the design of nanotechnologies for combinatorial drug delivery systems. The opportunities and challenges of nanotechnologies in drug delivery to overcome current disadvantages are also discussed. Furthermore, we have added findings regarding the trends and perspectives regarding nanotechnologies for combinatorial anticancer drug delivery.

Design and Synthesis of ZnII -Coordination Polymers Anchored with NSAIDs: Metallovesicle Formation and Multi-drug Delivery

A series of coordination polymers synthesized from a bis-pyridyl linker, namely 4,4'-azopyridine (L), selected non-steroidal-anti-inflammatory drugs (NSAIDs), namely diclofenac (Dic), ibuprofen (Ibu), flurbiprofen (Flu), mefenamic acid (Mefe), and naproxen (Nap), and Zn(NO₃ )₂ were characterized by single crystal X-ray diffraction. One of the coordination polymers, namely CP3 derived from Flu, was able to form metallovesicles in DMSO, DMSO/H₂ O and DMSO/DMEM (biological media) as revealed by TEM, AFM and DLS. Metallovesicle formation by CP3 was further supported by loading a fluorescent dye, namely calcein, as well as an anti-cancer drug, doxorubicin hydrochloride (DOX), as revealed by UV-vis and emission spectra, and fluorescence microscopy. DOX-loaded metallovesicles of CP3 (DOX@CP3-vesicle) could be delivered in vitro to a highly aggressive human breast cancer cell line, namely MDA-MB-231, as revealed by MTT and cell migration assays, and also cell imaging performed under laser scanning confocal microscope (LSCM). Thus, a proof of concept for developing a multi-drug delivery system derived from a metallovesicle for delivering an anti-cancer drug to cancer cells is demonstrated for the first time.

A self-assembled, ROS-responsive Janus-prodrug for targeted therapy of inflammatory bowel disease

A self-assembled and oxidation-degradable Janus-prodrug, termed as Bud-ATK-Tem (B-ATK-T), was fabricated by ROS-responsive aromatized thioketal (ATK) linked anti-inflammatory drug budesonide (Bud) and antioxidant tempol (Tem). Benefiting from the hydrophobic interactions and π-π stacking interactions of ATK, prodrug B-ATK-T could self-assemble into nanoparticles (NP) in water containing lecithin and DSPE-PEG_2K. The morphology of B-ATK-T NP (approximate 100-120nm) was confirmed to be regular spherical by transmission electron microscope. B-ATK-T NP was endowed high drug loading content with 41.23% for Bud and 15.55% for Tem. The rapid drug release from B-ATK-T NP proceeded in an extensive reactive oxygen species (ROS)-dependent manner. More than 98% of Bud and Tem in B-ATK-T NP could release in the mimic inflammation microenvironment or phorbol-12-myristate-13-acetate (PMA)-stimulated macrophages within short time. The release of drugs in a simultaneous and proportional manner ensures that B-ATK-T NP can increase the combined efficacy of anti-inflammation and anti-oxidation. It is worth noting that B-ATK-T NP could be passively accumulated and dramatically increasing the maximum drugs concentration in the inflamed colon of mice with inflammatory bowel disease (IBD) by oral route, and avoiding potential systemic side effects. B-ATK-T NP could not only relieve colitis via inhibiting the expression of oxidative and proinflammatory mediators more than combination of free drugs, but also significantly reduce colitis-caused death. Taken together, the self-assembled, Janus-prodrug B-ATK-T NP is a promising candidate therapies for IBD, even for other inflammatory diseases.

Time-staggered delivery of erlotinib and doxorubicin by gold nanocages with two smart polymers for reprogrammable release and synergistic with photothermal therapy

Photochemotherapy is currently an effective anticancer therapy. Recently, it has been reported that cancer cells pretreated with epidermal growth factor receptor (EGFR) inhibitor erlotinib (Erl) can significantly synergize its apoptosis against the DNA damaging agent doxorubicin (Dox). As a result, we designed two gold nanocages (Au NCs) microcontainers covered with different smart polymer shell-PAA (pH responsive) and p (NIPAM-co-AM) (temperature responsive) containing Erl and Dox respectively. The acidic tumor microenvironment and NIR light irradiation can selectively activate the release of Erl and Dox. Time staggered release of Erl and Dox and photothermal therapy enhance the apoptotic signaling pathways, resulting in improved tumor cell killing in both MCF-7 (low EGFR expression) and A431 (very high EGFR expression) tumor cells, but more efficient in the latter. The photochemotherapy strategy controls the order and duration of drug exposure precisely in spatial and temporal, and significantly improves the therapeutic efficacy against high EGFR expressed tumors.

Synchronizing the release rates of salicylate and indomethacin from degradable chitosan hydrogel and its optimization by definitive screening design

Three types of ionically crosslinked (with citric acid) chitosan discs were loaded with the highly water- soluble drug, sodium salicylate (SS) and the poorly water-soluble drug, indomethacin (Ind). In separate experiments the hydrated discs were immersed in a de-crosslinking solution comprising of different concentrations of calcium chloride, which induced a controlled erosion of the discs, a process which was optimized to synchronize the release rates of the two drugs over a predetermined period of time. The optimization was accomplished by manipulating six factors: chitosan MW, its amount in the formulation, the concentration of the crosslinker agent, the concentration of the de-crosslinking agent in the dissolution medium, its pH and its temperature. A computerized multifactorial definitive screening design analysis assisted in minimizing the number of experiments. The quotient of the SS to Ind release rates, the difference factor f1, the similarity factor f2 and the combination of f1 and f2 were determined as the experimental responses. The computerized prediction profilers that were used to simulate the contribution of the experimental factors and their effect on the experimental responses led to a successful erodible formulation with a concomitant release of the two drugs over 150 min.

Advancements and Challenges in Multidomain Multicargo Delivery Vehicles

Reparative and regenerative processes are well-orchestrated temporal and spatial events that are governed by multiple cells, molecules, signaling pathways, and interactions thereof. Yet again, currently available implantable devices fail largely to recapitulate nature's complexity and sophistication in this regard. Herein, success stories and challenges in the field of layer-by-layer, composite, self-assembly, and core-shell technologies are discussed for the development of multidomain/multicargo delivery vehicles.

Multivesicular droplets: a cell model system to study compartmentalised biochemical reactions

Multivesicular vesicles (MVVs) are artificial liposomal structures widely used as a platform to study the compartmentalisation of cells and as a scaffold for artificial cell/protocell models. Current preparation techniques for MVVs, however, offer poor control on the size, lamellarity, and loading of inner lipid vesicles. Here, we introduce a microfluidic device for the production of multivesicular droplets (MVDs): a novel model system combining the ease of use and control of droplet microfluidics with the biological relevance of MVVs. We use a perfluorinated carrier phase with a biocompatible surfactant to generate monodisperse droplets of an aqueous giant unilamellar lipid vesicle suspension. The successful on-chip formation and stability of MVDs is verified through high-speed microscopy. For bright field or fluorescence microscopy inspection, the MVDs are trapped in an array where the integrity of both lipid vesicles and droplets is preserved for up to 15 minutes. Finally, we show a two-step enzymatic reaction that takes place across the lipid vesicle membranes; the second reaction step occurs in the vesicle's interior, where the enzyme is encapsulated, while both the substrate and fluorescent product permeate across the membrane. Our approach opens the possibility to mimic artificial organelles with optimised reaction parameters (pH, ions, etc.) in each compartment.

A stimuli responsive liposome loaded hydrogel provides flexible on-demand release of therapeutic agents

Lysolipid-based thermosensitive liposomes (LTSL) embedded in a chitosan-based thermoresponsive hydrogel matrix (denoted Lipogel) represents a novel approach for the spatiotemporal release of therapeutic agents. The entrapment of drug-loaded liposomes in an injectable hydrogel permits local liposome retention, thus providing a prolonged release in target tissues. Moreover, release can be controlled through the use of a minimally invasive external hyperthermic stimulus. Temporal control of release is particularly important for complex multi-step physiological processes, such as angiogenesis, in which different signals are required at different times in order to produce a robust vasculature. In the present work, we demonstrate the ability of Lipogel to provide a flexible, easily modifiable release platform. It is possible to tune the release kinetics of different drugs providing a passive release of one therapeutic agent loaded within the gel and activating the release of a second LTSL encapsulated agent via a hyperthermic stimulus. In addition, it was possible to modify the drug dosage within Lipogel by varying the duration of hyperthermia. This can allow for adaption of drug dosing in real time. As an in vitro proof of concept with this system, we investigated Lipogels ability to recruit stem cells and then elevate their production of vascular endothelial growth factor (VEGF) by controlling the release of a pro-angiogenic drug, desferroxamine (DFO) with an external hyperthermic stimulus. Initial cell recruitment was accomplished by the passive release of hepatocyte growth factor (HGF) from the hydrogel, inducing a migratory response in cells, followed by the delayed release of DFO from thermosensitive liposomes, resulting in a significant increase in VEGF expression. This delayed release could be controlled up to 14days. Moreover, by changing the duration of the hyperthermic pulse, a fine control over the amount of DFO released was achieved. The ability to trigger the release of therapeutic agents at a specific timepoint and control dosing level through changes in duration of hyperthermia enables sequential multi-dose profiles.

STATEMENT OF SIGNIFICANCE

This paper details the development of a heat responsive liposome loaded hydrogel for the controlled release of pro-angiogenic therapeutics. Lysolipid-based thermosensitive liposomes (LTSLs) embedded in a chitosan-based thermoresponsive hydrogel matrix represents a novel approach for the spatiotemporal release of therapeutic agents. This hydrogel platform demonstrates remarkable flexibility in terms of drug scheduling and sequencing, enabling the release of multiple agents and the ability to control drug dosing in a minimally invasive fashion. The possibility to tune the release kinetics of different drugs independently represents an innovative platform to utilise for a variety of treatments. This approach allows a significant degree of flexibility in achieving a desired release profile via a minimally invasive stimulus, enabling treatments to be tuned in response to changing symptoms and complications.

A robust and refillable magnetic sponge capsule for remotely triggered drug release

Numerous different delivery systems have been developed for local administration of drugs. However, their service lives generally depend on the payload depletion time and most of them are designed for one time use due to lack of drug replenishment abilities. To address this issue, a refillable magnetic porous polydimethylsiloxane (PDMS) capsule is proposed for remotely controlled drug delivery applications. An inner cavity is built in the sponge scaffold to provide space for drug storage and the refilling is accomplished by injecting drugs with a syringe. The rapid and reversible deformation of the magnetic porous structure under a magnetic field offers a controlled pumping force to push drugs out of the capsule. In this work, low molecular weight (methylene blue, MB, 320 g mol^-1) and high molecular weight (bovine serum albumin, BSA, 67 000 g mol^-1) molecules were used as model compounds to test and verify the operational principle. This proof-of-concept study has demonstrated the capability of the refillable porous capsule in controlled drug delivery under external magnetic stimuli.

PEG-b-PLA micelles and PLGA-b-PEG-b-PLGA sol-gels for drug delivery

Poly(ethylene glycol)-block-poly(D,L-lactic acid) (PEG-b-PLA) micelles and poly(D,L-lactic-co-glycolic acid)-block-polyethylene glycol)-block-poly(D,L-lactic-co-glycolic acid) (PLGA-b-PEG-b-PLGA) sol-gels have been extensively researched for systemic and localized drug delivery applications, respectively, and they have both progressed into humans for paclitaxel, an important yet poorly water-soluble chemotherapeutic agent. In this review article, preclinical and clinical research on PEG-b-PLA micelles and PLGA-b-PEG-b-PLGA sol-gels that has focused on paclitaxel will be updated, and recent research on other poorly water-soluble anticancer agents and delivery of drug combinations (i.e. multi-drug delivery) that seeks synergistic anticancer efficacy will be summarized. PEG-b-PLA micelles are a first-generation platform for the systemic multi-delivery of poorly water soluble anticancer agents. PLGA-b-PEG-b-PLGA sol-gels are a first-generation platform for the localized multi-drug delivery of water-soluble and/or poorly water-soluble anticancer agents. In summary, PEG-b-PLA micelles and PLGA-b-PEG-b-PLGA sol-gels may safely enable pre-clinical evaluation and clinical translation of poorly water-soluble anticancer agents, especially for promising, rapidly emerging anticancer combinations.

Selective Release of Hydrophobic and Hydrophilic Cargos from Multi-Stimuli-Responsive Nanogels

Highly stable multi-stimuli-responsive nanogels for selective release of simultaneously encapsulated hydrophobic and hydrophilic cargos in a spatiotemporally controlled manner are demonstrated here. The nanogel is composed of hydrophilic pH- and thermoresponsive poly(2-(dimethylamino)ethyl methacrylate) (PDMAEMA) and hydrophobic photocleavable o-nitrobenzyl (ONB) linkage. The hydrophobic cargos were noncovalently encapsulated into lipophilic interiors of the nanogels, while the hydrophilic cargos were chemically linked to the nanogel precursor polymer PDMAEMA through a redox-cleavable disulfide junction. For these dual-loaded nanogels, hydrophobic cargos can be released in response to temperature, pH, and UV light, while the hydrophilic cargos can be released in response to redox reagent. The stimuli-selective release of hydrophobic and hydrophilic cargos affords the system with great potential applications in combination chemotherapy, tissue engineering, anticorrosion, and smart nanoreactors.

Organic nanoparticle systems for spatiotemporal control of multimodal chemotherapy

INTRODUCTION

Chemotherapeutic drugs are used in combination to target multiple mechanisms involved in cancer cell survival and proliferation. Carriers are developed to deliver drug combinations to common target tissues in optimal ratios and desirable sequences. Nanoparticles (NP) have been a popular choice for this purpose due to their ability to increase the circulation half-life and tumor accumulation of a drug. Areas covered: We review organic NP carriers based on polymers, proteins, peptides, and lipids for simultaneous delivery of multiple anticancer drugs, drug/sensitizer combinations, drug/photodynamic therapy or drug/photothermal therapy combinations, and drug/gene therapeutics with examples in the past three years. Sequential delivery of drug combinations, based on either sequential administration or built-in release control, is introduced with an emphasis on the mechanistic understanding of such control. Expert opinion: Recent studies demonstrate how a drug carrier can contribute to co-localizing drug combinations in optimal ratios and dosing sequences to maximize the synergistic effects. We identify several areas for improvement in future research, including the choice of drug combinations, circulation stability of carriers, spatiotemporal control of drug release, and the evaluation and clinical translation of combination delivery.

Therapeutic application of extracellular vesicles in acute and chronic renal injury

A new cell-to-cell communication system was discovered in the 1990s, which involves the release of vesicles into the extracellular space. These vesicles shuttle bioactive particles, including proteins, mRNA, miRNA, metabolites, etc. This particular communication has been conserved throughout evolution, which explains why most cell types are capable of producing vesicles. Extracellular vesicles (EVs) are involved in the regulation of different physiological processes, as well as in the development and progression of several diseases. EVs have been widely studied over recent years, especially those produced by embryonic and adult stem cells, blood cells, immune system and nervous system cells, as well as tumour cells. EV analysis from bodily fluids has been used as a diagnostic tool for cancer and recently for different renal diseases. However, this review analyses the importance of EVs generated by stem cells, their function and possible clinical application in renal diseases and kidney transplantation.

Photonanomedicine: a convergence of photodynamic therapy and nanotechnology

As clinical nanomedicine has emerged over the past two decades, phototherapeutic advancements using nanotechnology have also evolved and impacted disease management. Because of unique features attributable to the light activation process of molecules, photonanomedicine (PNM) holds significant promise as a personalized, image-guided therapeutic approach for cancer and non-cancer pathologies. The convergence of advanced photochemical therapies such as photodynamic therapy (PDT) and imaging modalities with sophisticated nanotechnologies is enabling the ongoing evolution of fundamental PNM formulations, such as Visudyne®, into progressive forward-looking platforms that integrate theranostics (therapeutics and diagnostics), molecular selectivity, the spatiotemporally controlled release of synergistic therapeutics, along with regulated, sustained drug dosing. Considering that the envisioned goal of these integrated platforms is proving to be realistic, this review will discuss how PNM has evolved over the years as a preclinical and clinical amalgamation of nanotechnology with PDT. The encouraging investigations that emphasize the potent synergy between photochemistry and nanotherapeutics, in addition to the growing realization of the value of these multi-faceted theranostic nanoplatforms, will assist in driving PNM formulations into mainstream oncological clinical practice as a necessary tool in the medical armamentarium.

Rationally Designed 2-in-1 Nanoparticles Can Overcome Adaptive Resistance in Cancer

The development of resistance is the major cause of mortality in cancer. Combination chemotherapy is used clinically to reduce the probability of evolution of resistance. A similar trend toward the use of combinations of drugs is also emerging in the application of cancer nanomedicine. However, should a combination of two drugs be delivered from a single nanoparticle or should they be delivered in two different nanoparticles for maximal efficacy? We explored these questions in the context of adaptive resistance, which emerges as a phenotypic response of cancer cells to chemotherapy. We studied the phenotypic dynamics of breast cancer cells under cytotoxic chemotherapeutic stress and analyzed the data using a phenomenological mathematical model. We demonstrate that cancer cells can develop adaptive resistance by entering into a predetermined transitional trajectory that leads to phenocopies of inherently chemoresistant cancer cells. Disrupting this deterministic program requires a unique combination of inhibitors and cytotoxic agents. Using two such combinations, we demonstrate that a 2-in-1 nanomedicine can induce greater antitumor efficacy by ensuring that the origins of adaptive resistance are terminated by deterministic spatially constrained delivery of both drugs to the target cells. In contrast, a combination of free-form drugs or two nanoparticles, each carrying a single payload, is less effective, arising from a stochastic distribution to cells. These findings suggest that 2-in-1 nanomedicines could emerge as an important strategy for targeting adaptive resistance, resulting in increased antitumor efficacy.

Dual responsive mesoporous silica nanoparticles for targeted co-delivery of hydrophobic and hydrophilic anticancer drugs to tumor cells

Dual responsive mesoporous silica nanoparticles (MSNs) integrating stepwise tumor targeting and co-delivery of multiple anticancer drugs were developed to attenuate the drug resistance of cancer cells (SCC cells). The nano-composite consists of MSNs as nanocarrier I for hydrophobic drugs delivery, generation 2 PAMAM dendrimer (PAMAM-G2) as nanocarrier II for hydrophilic drug delivery and hyaluronic acid (HA) as a tumor targeting agent, which effectively encapsulated drug molecules and blocked their outward diffusion from the mesopores of the MSNs before selective accumulation around the tumor. The responsive drug releases happened with cap (HA and PAMAM-G2) removal following tumor targeting and cell endocytosis, which was triggered by two intracellular stimuli, a low pH value (hydrophilic drug release) and glutathione (hydrophobic drug release). The highly selective particle-uptake by tumor cells and subsequent efficient drug co-delivery to these cells, which were directly demonstrated by fluorescence microscopy, resulted in a fourfold efficacy against tumor cells compared with normal cells, as well as higher tumor cytotoxicity than that caused by free drugs. These results indicate that this MSNs-dendrimer-HA construct, with performance of selective drug co-delivery and dual responsive drug release, could be a promising platform for cancer therapy.

"Combo" nanomedicine: Co-delivery of multi-modal therapeutics for efficient, targeted, and safe cancer therapy

The dynamic and versatile nature of diseases such as cancer has been a pivotal challenge for developing efficient and safe therapies. Cancer treatments using a single therapeutic agent often result in limited clinical outcomes due to tumor heterogeneity and drug resistance. Combination therapies using multiple therapeutic modalities can synergistically elevate anti-cancer activity while lowering doses of each agent, hence, reducing side effects. Co-administration of multiple therapeutic agents requires a delivery platform that can normalize pharmacokinetics and pharmacodynamics of the agents, prolong circulation, selectively accumulate, specifically bind to the target, and enable controlled release in target site. Nanomaterials, such as polymeric nanoparticles, gold nanoparticles/cages/shells, and carbon nanomaterials, have the desired properties, and they can mediate therapeutic effects different from those generated by small molecule drugs (e.g., gene therapy, photothermal therapy, photodynamic therapy, and radiotherapy). This review aims to provide an overview of developing multi-modal therapies using nanomaterials ("combo" nanomedicine) along with the rationale, up-to-date progress, further considerations, and the crucial roles of interdisciplinary approaches.

Advances and Challenges of Liposome Assisted Drug Delivery

The application of liposomes to assist drug delivery has already had a major impact on many biomedical areas. They have been shown to be beneficial for stabilizing therapeutic compounds, overcoming obstacles to cellular and tissue uptake, and improving biodistribution of compounds to target sites in vivo. This enables effective delivery of encapsulated compounds to target sites while minimizing systemic toxicity. Liposomes present as an attractive delivery system due to their flexible physicochemical and biophysical properties, which allow easy manipulation to address different delivery considerations. Despite considerable research in the last 50 years and the plethora of positive results in preclinical studies, the clinical translation of liposome assisted drug delivery platforms has progressed incrementally. In this review, we will discuss the advances in liposome assisted drug delivery, biological challenges that still remain, and current clinical and experimental use of liposomes for biomedical applications. The translational obstacles of liposomal technology will also be presented.

Delivery of doxorubicin and paclitaxel from double-layered microparticles: The effects of layer thickness and dual-drug vs. single-drug loading

Double-layered microparticles composed of poly(d,l-lactic-co-glycolic acid, 50:50) (PLGA) and poly(l-lactic acid) (PLLA) were loaded with doxorubicin HCl (DOX) and paclitaxel (PCTX) through a solvent evaporation technique. DOX was localized in the PLGA shell, while PCTX was localized in the PLLA core. The aim of this study was to investigate how altering layer thickness of dual-drug, double-layered microparticles can influence drug release kinetics and their antitumor capabilities, and against single-drug microparticles. PCTX-loaded double-layered microparticles with denser shells retarded the initial release of PCTX, as compared with dual-drug-loaded microparticles. The DOX release from both DOX-loaded and dual-drug-loaded microparticles were observed to be similar with an initial burst. Through specific tailoring of layer thicknesses, a suppressed initial burst of DOX and a sustained co-delivery of two drugs can be achieved over 2months. Viability studies using spheroids of MCF-7 cells showed that controlled co-delivery of PCTX and DOX from dual-drug-loaded double-layered microparticles were better in reducing spheroid growth rate. This study provides mechanistic insights into how by tuning the layer thickness of double-layered microparticles the release kinetics of two drugs can be controlled, and how co-delivery can potentially achieve better anticancer effects.

STATEMENT OF SIGNIFICANCE

While the release of multiple drugs has been reported to achieve successful apoptosis and minimize drug resistance, most conventional particulate systems can only deliver a single drug at a time. Recently, although a number of formulations (e.g. micellar nanoparticles, liposomes) have been successful in delivering two or more anticancer agents, sustained co-delivery of these agents remains inadequate due to the complex agent loading processes and rapid release of hydrophilic agents. Therefore, the present work reports the multilayered particulate system that simultaneously hosts different drugs, while being able to tune their individual release over months. We believe that our findings would be of interest to the readers of Acta Biomaterialia because the proposed system could open a new avenue on how two drugs can be released, through rate-controlling carriers, for combination chemotherapy.

Towards nanomedicines of the future: Remote magneto-mechanical actuation of nanomedicines by alternating magnetic fields

The paper describes the concept of magneto-mechanical actuation of single-domain magnetic nanoparticles (MNPs) in super-low and low frequency alternating magnetic fields (AMFs) and its possible use for remote control of nanomedicines and drug delivery systems. The applications of this approach for remote actuation of drug release as well as effects on biomacromolecules, biomembranes, subcellular structures and cells are discussed in comparison to conventional strategies employing magnetic hyperthermia in a radio frequency (RF) AMF. Several quantitative models describing interaction of functionalized MNPs with single macromolecules, lipid membranes, and proteins (e.g. cell membrane receptors, ion channels) are presented. The optimal characteristics of the MNPs and an AMF for effective magneto-mechanical actuation of single molecule responses in biological and bio-inspired systems are discussed. Altogether, the described studies and phenomena offer opportunities for the development of novel therapeutics both alone and in combination with magnetic hyperthermia.

Computational design and experimental characterization of peptides intended for pH-dependent membrane insertion and pore formation

There are many opportunities to use macromolecules, such as peptides and oligonucleotides, for intracellular applications. Despite this, general methods for delivering these molecules to the cytosol in a safe and efficient manner are not available. Efforts to develop a variety of intracellular drug delivery systems such as viral vectors, lipoplexes, nanoparticles, and amphiphilic peptides have been made, but various challenges such as delivery efficiency, toxicity, and controllability remain. A central challenge is the ability to selectively perturb, not destroy, the membrane to facilitate cargo introduction. Herein, we describe our efforts to design and characterize peptides that form pores inside membranes at acidic pH, so-called pH-switchable pore formation (PSPF) peptides, as a potential means for facilitating cargo translocation through membranes. Consistent with pore formation, these peptides exhibit low-pH-triggered selective release of ATP and miRNA, but not hemoglobin, from red blood cells. Consistent with these observations, biophysical studies (tryptophan fluorescence, circular dichroism, size-exclusion chromatography, analytical ultracentrifugation, and attenuated total reflectance Fourier transformed infrared spectroscopy) show that decreased pH destabilizes the PSPF peptides in aqueous systems while promoting their membrane insertion. Together, these results suggest that reduced pH drives insertion of PSPF peptides into membranes, leading to target-specific escape through a proposed pore formation mechanism.

Robust, flexible, and bioadhesive free-standing films for the co-delivery of antibiotics and growth factors

Free-standing polymer films that adhere strongly to tissue and can codeliver multiple therapeutic agents in a controlled manner are useful as medical plasters. In this study, a bilayer polymer film comprising a drug reservoir layer and a supporting layer is fabricated by spin-coating poly(lactic-co-glycolic acid) (PLGA) on top of a layer-by-layer assembled film of poly(β-amino esters) (PAE), alginate sodium (ALG), and recombinant human basic fibroblast growth factor (bFGF). Apart from bFGF, the bilayer film can also load antibiotic drug ceftriaxone sodium (CTX) by a postdiffusion process. The PLGA supporting layer facilitates the direct peeling of the bilayer film from substrate to produce a robust and flexible free-standing film with excellent adhesion onto the human skin and porcine liver. The excellent adhesion of the bilayer film originates from the ALG component in the drug reservoir layer. CTX is quickly released by easily breaking its electrostatic interaction with the drug reservoir layer, whereas the sustained release of bFGF is due to the slow degradation of PAE component in the drug reservoir layer. Wounds can be synergetically treated by fast release of CTX to effectively eradicate invasive bacteria and by sustained release of bFGF to accelerate wound healing. Our results serve as a basis for designing multifunctional free-standing films with combination therapy for biomedical applications.

Mulberry-like dual-drug complicated nanocarriers assembled with apogossypolone amphiphilic starch micelles and doxorubicin hyaluronic acid nanoparticles for tumor combination and targeted therapy

A comprehensive strategy for the preparation of mulberry-like dual-drug complicated nanocarriers (MLDC NCs) with high drug loading and adjustable dual-drug ratio was developed. First, apogossypolone (ApoG2) amphiphilic starch micelles (AASt MCs) were prepared by self-assembly process, and doxorubicin (DOX) hyaluronic acid nanoparticles (DHA NPs) were prepared by DOX absorption with excess HA by electrostatic absorption. MLDC NCs were obtained by adsorption of 8-9 DHA NPs around one AASt MC via electrostatic interaction. UV-visible and fluorescence spectrophotometers were used to measure the entrapment efficiency and loading efficiency of the two drugs. Transmission electron microscope and dynamic light scattering method were used to observe the size distribution and morphology of the particles. The tumor-targeting feature caused by HA-receptor mediation was confirmed by in vitro cell uptake and in vivo near-infrared fluorescence imaging. MLDC NCs were found to possess a mulberry-like shape with a dynamic size of 83.1 ± 6.6 nm. The final encapsulation efficiencies of ApoG2 and DOX in MLDC NCs were 94 ± 1.7% and 87 ± 5.8% with respect to drug-loading capacities of 13.3 ± 1.2% and 13.1 ± 3.7%, respectively. Almost no ApoG2 release was found within 80 h and less than 30% of DOX was released into the outer phase even after 72 h. In vivo fluorescence imaging revealed that MLDC NCs had highly efficient targeting and accumulation at the tumor in vivo and was maintained for 96 h after being injected intravenously in mice. Low LD50 for the two drugs in MLDC NCs was found after acute toxicity test. One-fifth normal dosage of the two drugs in MLDC NCs exhibited significantly higher anti-tumor efficiency in reducing tumor size compared with free drugs combination or single drug-loaded nanoparticles individually, indicating that the mulberry-like dual-drug nanoplatform has a great potential in tumor therapy.

Controlled co-delivery nanocarriers based on mixed micelles formed from cyclodextrin-conjugated and cross-linked copolymers

The combination of multiple drugs within a single nanocarrier can provide significant advantages for disease therapy and it is desirable to introduce a second drug based on host-guest interaction in these co-delivery systems. In this study, a core-stabilized mixed micellar system consisting of β-cyclodextrin-conjugated poly(lactic acid)-b-poly(ethylene glycol) (β-CD-PLA-mPEG) and DL-Thioctic acid (TA) terminated PLA-mPEG (TA-PLA-mPEG) was developed for the co-delivery of DOX and fluorescein isothiocyanate labeled adamantane (FA). DOX can be loaded within the hydrophobic segment of PLA and FA may form stable complexation with β-CD in the core. The mixed micelles (MM) are based on well-accepted medical materials and can be easily cross-linked by adding 1,4-dithio-D,L-threitol (DTT), which can enhance the stability of the system. Drug-loaded MM system was characterized in terms of particle size, morphology, drug loading and in vitro release profile. Cytotoxicity test showed that blank MM alone showed negligible cytotoxicity whereas the drug-loaded MM remained relatively high cytotoxicity for HeLa cancer cells. Confocal laser scanning microscopy (CLSM) demonstrated that the MM could efficiently deliver and release DOX and FA in the same tumor cells to effectively improve drugs' bioavailability. These results suggested that the core-stabilized MM are highly promising for intracellular co-delivery of multiple drugs.