Hydrogels as intracellular depots for drug delivery

Nanomaterials for detection of biomolecules and delivering therapeutic agents in theragnosis: A review

Nanomaterials are emerging facts used to deliver therapeutic agents in living systems. Nanotechnology is used as a compliment by implementing different kinds of nanotechnological applications such as nano-porous structures, functionalized nanomaterials, quantum dots, carbon nanomaterials, and polymeric nanostructures. The applications are in the initial stage, which led to achieving several diagnoses and therapy in clinical practice. This review conveys the importance of nanomaterials in post-genomic employment, which includes the design of immunosensors, immune assays, and drug delivery. In this view, genomics is a molecular tool containing large databases that are useful in choosing an apt molecular inhibitor such as drug, ligand and antibody target in the drug delivery process. This study identifies the expression of genes and proteins in analysis and classification of diseases. Experimentally, the study analyses the design of a disease model. In particular, drug delivery is a boon area to treat cancer. The identified drugs enter different phase trails (Trails I, II, and III). The genomic information conveys more essential entities to the phase I trials and helps to move further for other trails such as trails-II and III. In such cases, the biomarkers play a crucial role by monitoring the unique pathological process. Genetic engineering with recombinant DNA techniques can be employed to develop genetically engineered disease models. Delivering drugs in a specific area is one of the challenging issues achieved using nanoparticles. Therefore, genomics is considered as a vast molecular tool to identify drugs in personalized medicine for cancer therapy.

pH-Responsive nanofiber buttresses as local drug delivery devices

Electrospun nanofibers are a 3D scaffold of choice for many drug delivery devices due to their high surface area, significant capacity for drug payload, ease of in situ placement, and scalable manufacture. Herein, we report the synthesis of polymeric, pH-responsive nanofiber buttresses via electrospinning. The homopolymer is comprised of an acrylic backbone with acid-sensitive, hydrolyzable, trimethoxybenzaldehyde-protected side chains that lead to buttress transformation from a hydrophobic to a hydrophilic state under physiologically relevant pH conditions (e.g., extracellular tumor environment with pH = 6.5). Hydrolysis of the side chains leads to an increase in fiber diameter from approximately 350 to 900 nm and the release of the encapsulated drug cargo. In vitro drug release profiles demonstrate that significantly more drug is released at pH 5.5 compared to pH 7.4, thereby limiting the release to the target site, with docetaxel releasing over 20 days and doxorubicin over 7 days. Drug burst release, defined as >50% within 24 hours, does not occur at either pH or with either drug. Drug-loaded buttresses preserve drug activity and are cytotoxic to multiple human cancer lines, including breast and lung. Important to their potential application in surgical applications, the tensile strength of the buttresses is 6.3 kPa and, though weaker than commercially available buttresses, they provide sufficient flexibility and mechanical integrity to serve as buttressing materials via the application with a conventional surgical cutting stapler.

Advances in Lung Cancer Treatment Using Nanomedicines

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

Highly Specific and Sensitive Fluorescent Nanoprobes for Image-Guided Resection of Sub-Millimeter Peritoneal Tumors

A current challenge in the treatment of peritoneal carcinomatosis is the inability to detect, visualize, and resect small or microscopic tumors of pancreatic, ovarian, or mesothelial origin. In these diseases, the completeness of primary tumor resection is directly correlated with patient survival, and hence, identifying small sub-millimeter tumors (i.e., disseminated disease) is critical. Thus, new imaging techniques and probes are needed to improve cytoreductive surgery and patient outcomes. Highly fluorescent rhodamine-labeled expansile nanoparticles (HFR-eNPs) are described for use as a visual aid during cytoreductive surgery of pancreatic carcinomatosis. The covalent incorporation of rhodamine into ∼30 nm eNPs increases the fluorescent signal compared to free rhodamine, thereby affording a brighter and more effective probe than would be achieved by a single rhodamine molecule. Using the intraperitoneal route of administration, HFR-eNPs localize to regions of large (∼1 cm), sub-centimeter, and sub-millimeter intraperitoneal tumor in three different animal models, including pancreatic, mesothelioma, and ovarian carcinoma. Tumoral localization of the HFR-eNPs depends on both the material property (i.e., eNP polymer) as well as the surface chemistry (anionic surfactant vs PEGylated noncharged surfactant). In a rat model of pancreatic carcinomatosis, HFR-eNP identification of tumor is validated against gold-standard histopathological analysis to reveal that HFR-eNPs possess high specificity (99%) and sensitivity (92%) for tumors, in particular, sub-centimeter and microscopic sub-millimeter tumors, with an overall accuracy of 95%. Finally, as a proof-of-concept, HFR-eNPs are used to guide the resection of pancreatic tumors in a rat model of peritoneal carcinomatosis.

Nanoparticle drug-delivery systems for peritoneal cancers: a case study of the design, characterization and development of the expansile nanoparticle

Nanoparticle (NP)-based drug-delivery systems are frequently employed to improve the intravenous administration of chemotherapy; however, few reports explore their application as an intraperitoneal therapy. We developed a pH-responsive expansile nanoparticle (eNP) specifically designed to leverage the intraperitoneal route of administration to treat intraperitoneal malignancies, such as mesothelioma, ovarian, and pancreatic carcinomatoses. This review describes the design, evaluation, and evolution of the eNP technology and, specifically, a Materials-Based Targeting paradigm that is unique among the many active- and passive-targeting strategies currently employed by NP-delivery systems. pH-responsive eNP swelling is responsible for the extended residence at the target tumor site as well as the subsequent improvement in tumoral drug delivery and efficacy observed with paclitaxel-loaded eNPs (PTX-eNPs) compared to the standard clinical formulation of paclitaxel, Taxol®. Superior PTX-eNP efficacy is demonstrated in two different orthotopic models of peritoneal cancer-mesothelioma and ovarian cancer; in a third model-of pancreatic cancer-PTX-eNPs demonstrated comparable efficacy to Taxol with reduced toxicity. Furthermore, the unique structural and responsive characteristics of eNPs enable them to be used in three additional treatment paradigms, including: treatment of lymphatic metastases in breast cancer; use as a highly fluorescent probe to visually guide the resection of peritoneal implants; and, in a two-step delivery paradigm for concentrating separately administered NP and drug at a target site. This case study serves as an important example of using the targeted disease-state's pathophysiology to inform the NP design as well as the method of use of the delivery system. WIREs Nanomed Nanobiotechnol 2017, 9:e1451. doi: 10.1002/wnan.1451 For further resources related to this article, please visit the WIREs website.

Nanoparticle tumor localization, disruption of autophagosomal trafficking, and prolonged drug delivery improve survival in peritoneal mesothelioma

The treatment outcomes for malignant peritoneal mesothelioma are poor and associated with high co-morbidities due to suboptimal drug delivery. Thus, there is an unmet need for new approaches that concentrate drug at the tumor for a prolonged period of time yielding enhanced antitumor efficacy and improved metrics of treatment success. A paclitaxel-loaded pH-responsive expansile nanoparticle (PTX-eNP) system is described that addresses two unique challenges to improve the outcomes for peritoneal mesothelioma. First, following intraperitoneal administration, eNPs rapidly and specifically localize to tumors. The rate of eNP uptake by tumors is an order of magnitude faster than the rate of uptake in non-malignant cells; and, subsequent accumulation in autophagosomes and disruption of autophagosomal trafficking leads to prolonged intracellular retention of eNPs. The net effect of these combined mechanisms manifests as rapid localization to intraperitoneal tumors within 4 h of injection and persistent intratumoral retention for >14 days. Second, the high tumor-specificity of PTX-eNPs leads to delivery of greater than 100 times higher concentrations of drug in tumors compared to PTX alone and this is maintained for at least seven days following administration. As a result, overall survival of animals with established mesothelioma more than doubled when animals were treated with multiple doses of PTX-eNPs compared to equivalent dosing with PTX or non-responsive PTX-loaded nanoparticles.

Evaluation of expansile nanoparticle tumor localization and efficacy in a cancer stem cell-derived model of pancreatic peritoneal carcinomatosis

AIM

To evaluate the tumor localization and efficacy pH-responsive expansile nanoparticles (eNPs) as a drug delivery system for pancreatic peritoneal carcinomatosis (PPC) modeled in nude rats.

METHODS & MATERIALS

A Panc-1-cancer stem cell xeno1graft model of PPC was validated in vitro and in vivo. Tumor localization was tracked via in situ imaging of fluorescent eNPs. Survival of animals treated with paclitaxel-loaded eNPs (PTX-eNPs) was evaluated in vivo.

RESULTS

The Panc-1-cancer stem cell xenograft model recapitulates significant features of PPC. Rhodamine-labeled eNPs demonstrate tumor-specific, dose- and time-dependent localization to macro- and microscopic tumors following intraperitoneal injection. PTX-eNPs are as effective as free PTX in treating established PPC; but, PTX-eNPs result in fewer side effects.

CONCLUSION

eNPs are a promising tool for the detection and treatment of PPC.

3D hydrogel scaffold doped with 2D graphene materials for biosensors and bioelectronics

Hydrogels consisting of three-dimensional (3D) polymeric networks have found a wide range of applications in biotechnology due to their large water capacity, high biocompatibility, and facile functional versatility. The hydrogels with stimulus-responsive swelling properties have been particularly instrumental to realizing signal transduction in biosensors and bioelectronics. Graphenes are two-dimensional (2D) nanomaterials with unprecedented physical, optical, and electronic properties and have also found many applications in biosensors and bioelectronics. These two classes of materials present complementary strengths and limitations which, when effectively coupled, can result in significant synergism in their electrical, mechanical, and biocompatible properties. This report reviews recent advances made with hydrogel and graphene materials for the development of high-performance bioelectronics devices. The report focuses on the interesting intersection of these materials wherein 2D graphenes are hybridized with 3D hydrogels to develop the next generation biosensors and bioelectronics.

Two-Step Delivery: Exploiting the Partition Coefficient Concept to Increase Intratumoral Paclitaxel Concentrations In vivo Using Responsive Nanoparticles

Drug dose, high local target tissue concentration, and prolonged duration of exposure are essential criteria in achieving optimal drug performance. However, systemically delivered drugs often fail to effectively address these factors with only fractions of the injected dose reaching the target tissue. This is especially evident in the treatment of peritoneal cancers, including mesothelioma, ovarian, and pancreatic cancer, which regularly employ regimens of intravenous and/or intraperitoneal chemotherapy (e.g., gemcitabine, cisplatin, pemetrexed, and paclitaxel) with limited results. Here, we show that a “two-step” nanoparticle (NP) delivery system may address this limitation. This two-step approach involves the separate administration of NP and drug where, first, the NP localizes to tumor. Second, subsequent administration of drug then rapidly concentrates into the NP already stationed within the target tissue. This two-step method results in a greater than 5-fold increase in intratumoral drug concentrations compared to conventional “drug-alone” administration. These results suggest that this unique two-step delivery may provide a novel method for increasing drug concentrations in target tissues.

Dual acid-responsive supramolecular nanoparticles as new anticancer drug delivery systems

In this article, a dual acid-responsive drug delivery system has been fabricated via simple host–guest recognition.

Personalizing Biomaterials for Precision Nanomedicine Considering the Local Tissue Microenvironment

New advances in (nano)biomaterial design coupled with the detailed study of tissue-biomaterial interactions can open a new chapter in personalized medicine, where biomaterials are chosen and designed to match specific tissue types and disease states. The notion of a "one size fits all" biomaterial no longer exists, as growing evidence points to the value of customizing material design to enhance (pre)clinical performance. The complex microenvironment in vivo at different tissue sites exhibits diverse cell types, tissue chemistry, tissue morphology, and mechanical stresses that are further altered by local pathology. This complex and dynamic environment may alter the implanted material's properties and in turn affect its in vivo performance. It is crucial, therefore, to carefully study tissue context and optimize biomaterials considering the implantation conditions. This practice would enable attaining predictable material performance and enhance clinical outcomes.

Synthesis and Characterization of Hybrid Polymer/Lipid Expansile Nanoparticles: Imparting Surface Functionality for Targeting and Stability

The size, drug loading, drug release kinetics, localization, biodistribution, and stability of a given polymeric nanoparticle (NP) system depend on the composition of the NP core as well as its surface properties. In this study, novel, pH-responsive, and lipid-coated NPs, which expand in size from a diameter of approximately 100 to 1000 nm in the presence of a mildly acidic pH environment, are synthesized and characterized. Specifically, a combined miniemulsion and free-radical polymerization method is used to prepare the NPs in the presence of PEGylated lipids. These PEGylated-lipid expansile NPs (PEG-L-eNPs) combine the swelling behavior of the polymeric core of expansile NPs with the improved colloidal stability and surface functionality of PEGylated liposomes. The surface functionality of PEG-L-eNPs allows for the incorporation of folic acid (FA) and folate receptor-targeting. The resulting hybrid polymer/lipid nanocarriers, FA-PEG-L-eNPs, exhibit greater in vitro uptake and potency when loaded with paclitaxel compared to nontargeted PEG-L-eNPs.

Design, synthesis and biological assessment of a triazine dendrimer with approximately 16 Paclitaxel groups and 8 PEG groups

The synthesis and characterization of a generation three triazine dendrimer that displays a phenolic group at the core for labeling, up to eight 5 kDa PEG chains for solubility, and 16 paclitaxel groups is described. Three different diamine linkers--dipiperidine trismethylene, piperazine, and aminomethylpiperidine--were used within the dendrimer. To generate the desired stoichiometric ratio of 8 PEG chains to 16 paclitaxel groups, a monochlorotriazine was prepared with two paclitaxel groups attached through their 2'-hydroxyls using a linker containing a labile disulfide. This monochlorotriazine was linked to a dichlorotriazine with aminomethylpiperidine. The resulting dichlorotriazine bearing two paclitaxel groups could be reacted with the eight amines of the dendrimer. NMR and MALDI-TOF confirm successful reaction. The eight monochlorotriazines of the resulting material are used as the site for PEGylation affording the desired 2:1 stoichiometry. The target and intermediates were amenable to characterization by (1)H and (13)C NMR, and mass spectrometry. Analysis revealed that 16 paclitaxel groups were installed along with 5-8 PEG chains. The final construct is 63% PEG, 22% paclitaxel, and 15% triazine dendrimer. Consistent with previous efforts and computational models, 5 kDa PEG groups were essential for making the target water-soluble. Molecular dynamics simulations showed a high degree of hydration of the core, and a radius of gyration of 2.8 ± 0.2 nm. The hydrodynamic radius of the target was found to be 15.8 nm by dynamic light scattering, an observation indicative of aggregation. Drug release studies performed in plasma showed slow and identical release in mouse and rat plasma (8%, respectively). SPECT/CT imaging was used to follow biodistribution and tumor uptake. Using a two component model, the elimination and distribution half-lives were 2.65 h and 38.2 h, respectively. Compared with previous constructs, this dendrimer persists in the vasculature longer (17.33 ± 0.88% ID/g at 48 h postinjection), and showed higher tumor uptake. Low levels of dendrimer were observed in lung, liver, and spleen (~6% ID/g). Tumor saturation studies of small prostate cancer tumors (PC3) suggest that saturation occurs at a dose between 23.2 mg/kg and 70.9 mg/kg.

Nanotechnology-based intelligent drug design for cancer metastasis treatment

Traditional chemotherapy used today at clinics is mainly inherited from the thinking and designs made four decades ago when the Cancer War was declared. The potency of those chemotherapy drugs on in-vitro cancer cells is clearly demonstrated at even nanomolar levels. However, due to their non-specific effects in the body on normal tissues, these drugs cause toxicity, deteriorate patient's life quality, weaken the host immunosurveillance system, and result in an irreversible damage to human's own recovery power. Owing to their unique physical and biological properties, nanotechnology-based chemotherapies seem to have an ability to specifically and safely reach tumor foci with enhanced efficacy and low toxicity. Herein, we comprehensively examine the current nanotechnology-based pharmaceutical platforms and strategies for intelligent design of new nanomedicines based on targeted drug delivery system (TDDS) for cancer metastasis treatment, analyze the pros and cons of nanomedicines versus traditional chemotherapy, and evaluate the importance that nanomaterials can bring in to significantly improve cancer metastasis treatment.

Reaction-based and single fluorescent emitter decorated ratiometric nanoprobe to detect hydrogen peroxide

A novel reaction-based cross-linked polymeric nanoprobe with a self-calibrating ratiometric fluorescence readout to selectively detect H2O2 is reported. The polymeric nanoprobe is fabricated by using hydrophobic H2O2-reactive boronic ester groups, crosslinker units, and environmentally sensitive 3-hydroxyflavone fluorophores through a miniemulsion polymerization. On treatment with H2O2, the boronic esters in the polymer are cleaved to form hydrophilic alcohols and subsequently lead to a hydrophobic-hydrophilic transition. Covalently linked 3-hydroxyflavones manifest the change in polarity as a ratiometric transition from green to blue, accompanied by a 500-fold increase in volume. Furthermore, this nanoprobe has been used for ratiometric sensing of glucose by monitoring the H2O2 generated during the oxidation of glucose by glucose oxidase, and thus successfully distinguished between normal and pathological levels of glucose.

Emerging applications of nanoparticles for lung cancer diagnosis and therapy

Lung cancer is by far the leading cause of cancer-related mortality worldwide, most of them being active tobacco smokers. Non small cell lung cancer accounts for around 85% to 90% of deaths, whereas the rest is contributed by small cell lung cancer. The extreme lethality of lung cancer arises due to lack of suitable diagnostic procedures for early detection of lung cancer and ineffective conventional therapeutic strategies. In course with desperate attempts to address these issues independently, a multifunctional nanotherapeutic or diagnostic system is being sought as a favorable solution. The manifestation of physiochemical properties of such nanoscale systems is tuned favorably to come up with a versatile cancer cell targeted diagnostic and therapeutic system. Apart from this, the aspect of being at nanoscale by itself confers the system with an advantage of passive accumulation at the site of tumor. This review provides a broad perspective of three major subclasses of such nanoscale therapeutic and diagnostic systems which include polymeric nanoparticles-based approaches, metal nanoparticles-based approaches, and bio-nanoparticles-based approaches. This review work also serves the purpose of gaining an insight into the pros and cons of each of these approaches with a prospective improvement in lung cancer therapeutics and diagnostics.

Bioavailability of phytochemicals and its enhancement by drug delivery systems

Issues of poor oral bioavailability of cancer chemopreventives have hindered progress in cancer prevention. Novel delivery systems that modulate the pharmacokinetics of existing drugs, such as nanoparticles, cyclodextrins, niosomes, liposomes and implants, could be used to enhance the delivery of chemopreventive agents to target sites. The development of new approaches in prevention and treatment of cancer could encompass new delivery systems for approved and newly investigated compounds. In this review, we discuss some of the delivery approaches that have already made an impact by either delivering a drug to target tissue or increasing its bioavailability by many fold.

In vitro activity of Paclitaxel-loaded polymeric expansile nanoparticles in breast cancer cells

Through a series of in vitro studies, the essential steps for intracellular drug delivery of paclitaxel using a pH-responsive nanoparticle system have been investigated in breast cancer cells. We successfully encapsulated paclitaxel within polymeric expansile nanoparticles (Pax-eNPs) at 5% loading via a miniemulsion polymerization procedure. Fluorescently tagged eNPs were readily taken up by MDA-MB-231 breast cancer cells grown in culture as confirmed by confocal microscopy and flow cytometry. The ability of the encapsulated paclitaxel to reach the cytoplasm was also observed using confocal microscopy and fluorescently labeled paclitaxel. Pax-eNPs were shown to be efficacious against three in vitro human breast adenocarcinoma cell lines (MDA-MB-231, MCF-7, and SK-BR-3) as well as cells isolated from the pleural effusions of two different breast cancer patients. Lastly, macropinocytosis was identified as the major cellular pathway responsible for eNP uptake, as confirmed using temperature-sensitive metabolic reduction, pharmacologic inhibitors, and fluid-phase marker colocalization.

Microscopy and tunable resistive pulse sensing characterization of the swelling of pH-responsive, polymeric expansile nanoparticles

Polymeric expansile nanoparticles (eNPs) that respond to a mildly acidic environment by swelling with water and expanding 2-10× in diameter represent a new responsive drug delivery system. Here, we use a variety of techniques to characterize the pH- and time-dependence of eNP swelling as this is a key property responsible for the observed in vitro and in vivo performance of eNPs. Results demonstrate a significant change in eNP volume (>350×) at pH 5.0 as seen using: scanning electron microscopy (SEM), conventional transmission electron microscopy (TEM), freeze-fracture transmission electron microscopy (ff-TEM), fluorescence microscopy, and a new nanopore based characterization technology, the qNano, which measures both individual particle size as well as overall particle concentration in situ using tunable resistive pulse sensing. eNP swelling occurs in a continuous and yet heterogeneous manner over several days and is pH dependent.

Nanotechnology in therapeutics: a focus on nanoparticles as a drug delivery system

Continuing improvement in the pharmacological and therapeutic properties of drugs is driving the revolution in novel drug delivery systems. In fact, a wide spectrum of therapeutic nanocarriers has been extensively investigated to address this emerging need. Accordingly, this article will review recent developments in the use of nanoparticles as drug delivery systems to treat a wide variety of diseases. Finally, we will introduce challenges and future nanotechnology strategies to overcome limitations in this field.

Cytoreductive surgery and intraoperative administration of paclitaxel-loaded expansile nanoparticles delay tumor recurrence in ovarian carcinoma

BACKGROUND

Locoregional recurrence significantly impacts survival and quality of life in patients with ovarian carcinoma. We hypothesize that local administration of paclitaxel-loaded expansile nanoparticles (pax-eNP) at the time of cytoreductive surgery decreases local tumor recurrence.

METHODS

In vitro cytotoxicity of pax-eNP was assessed against both the OVCAR-3 human ovarian cancer cell line and tumor cells isolated from a malignant pleural effusion from a patient with multidrug-resistant ovarian cancer. A murine xenogenic model involving surgical cytoreduction of established OVCAR-3 intra-abdominal tumor was used to evaluate in vivo efficacy of intraoperative intraperitoneal (IP) injection of 10 mg/kg of paclitaxel either as pax-eNP or paclitaxel in Cremophor EL/ethanol solution (pax-C/E) versus empty eNP controls. Cytoreductive surgery and intraoperative treatment were performed 4 weeks after established tumor. All animals were sacrificed when empty eNP controls displayed extensive evidence of disease progression.

RESULTS

Labeled-eNP entered tumor cells in vitro within 4 h and specifically accumulated at sites of tumor in vivo. Pax-eNP exhibited dose-dependent cytotoxicity in both OVCAR-3 and patient tumor cells isolated from a malignant pleural effusion and effectively prevented tumor recurrence following debulking (p = 0.003 vs. empty eNP). Furthermore, pax-eNP-treated animals did not develop severe recurrent carcinomatosis compared with 43 % of the pax-C/E-treated cohort, suggesting that single-dose intracavitary pax-eNP is more effective than an equivalent dose of pax-C/E.

CONCLUSIONS

Expansile nanoparticles readily enter human ovarian tumor cells and localize to sites of tumor in vivo with pax-eNP cytotoxicity resulting in superior inhibition of locoregional tumor recurrence following cytoreductive surgery.

Biologically responsive polymeric nanoparticles for drug delivery

Responsive nanoparticles that release their drug cargo in accordance with a change in pH or oxidative stress are of significant clinical interest as this approach offers the opportunity to link drug delivery to a specific location or disease state. This research news article reviews the current state of this field by examining a series of published articles that highlight the novelty and benefits of using responsive polymeric particles to achieve functionally-targeted drug delivery.