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Cerebral aneurysms (CA), an abnormal bulge in the arteries that supply blood to the brain, are prone to rupture and can cause hemorrhagic stroke. Physicians can treat CA by blocking blood flow to the aneurysmal sac via clipping of the aneurysm neck via open procedure, or endovascular occlusion of the aneurysm with embolic materials to promote thrombus formation to prevent further inflow of blood into the aneurysm. Endovascular treatment options for CA still have significant limitations in terms of safety, usability in coagulopathic patients, and risks of device migration. Bioactive embolic therapies, consisting of non-toxic bioresorbable materials that encourage the growth of neointima across the aneurysm neck, are needed to improve the healing of CA. In this work, the bioinspired silk-elastinlike protein-based polymer (SELP 815K), was used to embolize aneurysms in a rabbit elastase model. SELP 815K effectively embolized the model aneurysms in vivo, achievinggt;90% occlusion, using commercial microcatheters. No device-associated adverse effects were observed in any of the animals, and SELP 815K showed no cytotoxicity. SELP embolization did not show any deleterious effects to local tissues, and features consistent with reendothelialization of the aneurysm neck were noted in histological examination one-month post-embolization. SELP 815K shows promise as an embolic treatment for unruptured CA. STATEMENT OF SIGNIFICANCE: Unruptured cerebral aneurysms are present in approximately 3% of the population, with a fatality rate of up to 65% upon rupture. In this work a silk-elastinlike protein polymer (SELP) is explored as a liquid embolic for occlusion of cerebral aneurysms. This embolic exists as a liquid at room temperature before rapidly forming a gel at physiological temperature. This shape filling property was used to successfully occlude cerebral aneurysms in rabbits, with stable occlusion persisting for over thirty days. SELP occlusions show evidence for reendothelialization of the aneurysm sac and provide an opportunity for delivery of bioactive agents to further improve treatments.

Air liquid interface (ALI) exposure systems are gaining interest, and studies suggest enhanced response of lung cells exposed to particles at ALI as compared to submerged exposure, although the results have been somewhat inconsistent. Previous studies have used monocultures and measured particle deposition using assumptions including consistent particle deposition, particle density, and shape. This study exposed co-cultures of A549 and differentiated THP-1 cells to flame-generated particles using three exposure methods: ALI, pseudo-ALI, and submerged. The dose at ALI was measured directly, reducing the need for assumptions about particle properties and deposition. For all exposure methods an enhanced pro-inflammatory response (TNFα) and Cytochrome P450 (CYP1A1) gene expression, compared to their corresponding negative controls, was observed. ALI exposure induced a significantly greater TNFα response compared to submerged exposure. The submerged exposures exhibited greater induction of CYP1A1 than other exposure methods, although not statistically significant. Some of the factors behind the observed difference in responses for the three exposure methods include differences in physicochemical properties of particles in suspending media, delivered dose, and potential contribution of gas-phase species to cellular response in ALI exposure. However, given the difficulty and expense of ALI exposures, submerged exposure may still provide relevant information for particulate exposures.

Although silica nanoparticles (SNPs) are generally thought to be biocompatible and safe, the adverse effects of SNPs were also reported in previous studies. SNPs cause follicular atresia via the induction of ovarian granulosa cell apoptosis. However, the mechanisms for this phenomenon are not well understood. This study focuses on exploring the relationship between autophagy and apoptosis induced by SNPs in ovarian granulosa cells. Our results showed that 25.0 mg/kg body weight (b.w.)/intratracheal instillation of 110 nm in diameter spherical Stöber SNPs caused ovarian granulosa cell apoptosis in follicles in vivo. We also found that SNPs mainly internalized into the lumens of the lysosomes in primary cultured ovarian granulosa cells in vitro. SNPs induced cytotoxicity via a decrease in viability and an increase in apoptosis in a dose-dependent manner. SNPs increased BECLIN-1 and LC3-II levels, leading to the activation of autophagy and increased P62 level, resulting in the blockage of autophagic flux. SNPs increased the BAX/BCL-2 ratio and cleaved the caspase-3 level, resulting in the activation of the mitochondrial-mediated caspase-dependent apoptotic signaling pathway. SNPs enlarged the LysoTracker Red-positive compartments, decreased the CTSD level, and increased the acidity of lysosomes, leading to lysosomal impairment. Our results reveal that SNPs cause autophagy dysfunction via lysosomal impairment, resulting in follicular atresia via the enhancement of apoptosis in ovarian granulosa cells.

Ambient particulate matters (PMs) have adverse effects in human and animal female reproductive health. Silica nanoparticles (SNPs), as a major component of PMs, can induce follicular atresia via the promotion of ovarian granulosa cell apoptosis. However, the molecular mechanisms of apoptosis induced by SNPs are not very clear. This work focuses on revealing the mechanisms of ER stress on SNP-induced apoptosis. Our results showed that spherical Stöber SNPs (110 nm, 25.0 mg/kg b.w.) induced follicular atresia via the promotion of granulosa cell apoptosis by intratracheal instillation in vivo; meanwhile, SNPs decreased the viability and increase apoptosis in granulosa cells in vitro. SNPs were taken up and accumulated in the vesicles of granulosa cells. Additionally, our results found that SNPs increased calcium ion (Ca

Silk-Elastinlike Protein-Based Polymers (SELPs) can form thermoresponsive hydrogels that allow for the generation of in-situ drug delivery matrices. They are produced by recombinant techniques, enabling exact control of monomer sequence and polymer length. In aqueous solutions SELP strands form physical crosslinks as a function of temperature increase without the addition of crosslinking agents. Gelation kinetics, modulus of elasticity, pore size, drug release, biorecognition, and biodegradation of SELP hydrogels can be controlled by placement of amino acid residues at strategic locations in the polymer backbone. SELP hydrogels have been investigated for delivery of a variety of bioactive agents including small molecular weight drugs and fluorescent probes, oligomers of glycosaminoglycans, polymeric macromolecules, proteins, plasmid DNA, and viral gene delivery systems. In this review we provide a background for use of SELPs in matrix-mediated delivery and summarize recent investigations of SELP hydrogels for controlled delivery of bioactive agents as well as their use as liquid embolics.

The extracellular matrix (ECM) is dynamically involved in many aspects of cell growth and survival, and it plays an active role in cancer etiology. In comparison to healthy ECM, tumor associated ECM shows high collagen deposition and remodeling activity, which results in an increased amount of denatured collagen strands in tumor tissues. Capitalizing on this distinguishing feature, we developed tumor-localizing polymeric carriers that selectively bind to denatured collagen in the tumor ECM. We synthesized N-(2-hydroxypropyl)methacrylamide (HPMA) copolymers with their side chains conjugated to collagen hybridizing peptides (CHPs). HPMA copolymer-CHP conjugates exhibited selective affinity to denatured collagen and localized to tumors in an orthotopic MDA-MB-231 murine breast cancer model. The conjugates had increased tumor localization compared to copolymers with scrambled peptides in the side chains, as well as increased retention compared to free CHPs. Such conjugates show promise as carriers for ECM-acting drugs and imaging agents in the management of diseases characterized by high ECM remodeling activity.

Atmospheric aging of combustion particles alters their chemical composition and morphology. Previous studies have reported differences in toxicological responses after exposure to fresh versus aged particles, with chemical composition being the prime suspect behind the differences. However, less is known about the contribution of morphological differences in atmospherically aged particles to toxicological responses, possibly due to the difficulty in resolving the two properties (composition and morphology) that change simultaneously. This study altered the shape of lab-generated combustion particles, without affecting the chemical composition, from fractal-like to a more compact spherical shape, using a water condensation-evaporation method. The two shapes were exposed to a co-culture of human airway epithelial (A549) and differentiated human monocyte (THP-1) cells at air-liquid interface (ALI) conditions. The particles with different shapes were deposited using an electrostatic field-based ALI chamber. For the same mass dose, both shapes were internalized by cells, induced a pro-inflammatory response (IL-8 and TNFα), and enhanced CYP1A1 gene expression compared to air controls. The more compact spherical particles (representative of atmospherically aged particles) induced more early apoptosis and release of TNFα compared to the more fractal-like particles. These results suggest a contribution of morphology to the increased toxicity of aged combustion-derived particles.

Locally blocking blood flow to tumors with embolic materials is key to transcatheter arterial embolization for treating hepatocellular carcinoma. Current microparticle agents do not deeply penetrate target tissues and are compatible with a very limited selection of therapeutic agents. Silk-elastinlike protein polymers (SELPs) combine the solubility of elastin and the strength of silk to create an easily injected liquid embolic that transitions into a solid depot amenable to loading with drugs, gene therapy agents, or biologics. SELP, injected as liquid solution, penetrates the vasculature before transitioning to a solid hydrogel. The objective of this manuscript was to evaluate SELP embolization, stability, and biocompatibility at 7-, 30-, and 90-day survival intervals in a porcine model. SELP embolics selectively block blood flow in the kidneys and livers, with no off-target infarctions. As assessed with angiography, SELP renal embolization exhibited decreasing persistence for the duration of the 90-day study period. There was an increased presence of microscopic SELP emboli in the renal setting, compared to Embosphere®. Histologically scored inflammatory reactions to SELP are decreased in both the renal and hepatic implantations compared to Embosphere®. In conclusion, a bioresorbable SELP liquid embolic system deeply penetrates target tissue and selectively embolizes blood vessels in vivo.

Semisynthetic glycosaminoglycan ethers (SAGEs) are short, sulfated hyaluronans which combine the natural properties of hyaluronan with chemical sulfation. In a murine model, SAGEs provide protection against radiation induced proctitis (RIP), a side effect of lower abdominal radiotherapy for cancer. The anti-inflammatory effects of SAGE have been studied in inflammatory diseases at mucosal barrier sites; however, few mechanisms have been uncovered necessitating high throughput methods. SAGEs were combined with silk-elastinlike polymers (SELPs) to enhance rectal accumulation in mice. After high radiation exposure to the lower abdominal area, mice were followed for 3 days or until they met humane endpoints, before evaluation of behavioral pain responses and histological assessment of rectal inflammation. RNA sequencing was conducted on tissues from the 3-day cohort to determine molecular mechanisms of SAGE–SELP. After 3 days, mice receiving the SAGE–SELP combination yielded significantly lowered pain responses and amelioration of radiation-induced rectal inflammation. Mice receiving the drug–polymer combination survived 60% longer than other irradiated mice, with a fraction exhibiting long term survival. Sequencing reveals varied regulation of toll like receptors, antioxidant activities, T-cell signaling, and pathways associated with pain. This investigation elucidates several molecular mechanisms of SAGEs and exhibits promising measures for prevention of RIP.

Despite increasing reports of using silica nanoparticles (SNPs) for controlled drug delivery applications, their long-term toxicity profile following intravenous administration remains unexplored. Herein, we investigated the acute (10-day) and subchronic (60-day and 180-day) toxicity of nonporous SNPs of approximately 50 nm (Stöber SNPs50) and approximately 500 nm in diameter (Stöber SNPs500), and mesoporous SNPs of approximately 500 nm in diameter (MSNPs500) upon single-dose intravenous injection into male and female immune-competent inbred BALB/C mice. The Maximum Tolerated Dose (MTD) of the particles was determined 10 days post-injection. The MTD of SNPs was administered and toxicity evaluated over 60 and 180 days. Results demonstrate that Stöber SNPs50 exhibit systemic toxicity with MTD of 103 ± 11 mg.kg(−1) for female and 100 ± 6 mg.kg(−1) for male mice, respectively. Toxicity was alleviated by increasing the size of the particles (Stöber SNPs500). MTD values of 303 ± 4 mg.kg(−1) for female and 300 ± 13 mg.kg(−1) for male were observed for Stöber SNPs500. Mesoporous SNPs500 showed considerable systemic sex-related toxicity, with MTDs ranging from 40 ± 2 mg.kg(−1) to 95 ± 2 mg.kg(−1) for male and female mice, respectively. Studies of SNPs showed blood toxicity as a function of physiochemical properties such as significant differences in the mean corpuscular hemoglobin (MCHC) and platelet number at day 10 and white blood cell count at day 60. Histological examination also showed size-, porosity- and time-dependent tissue toxicity. Stöber SNPs500 caused major toxic effects such as lung thrombosis, cardiac wall fibrosis and calcifications, brain infarctions with necrotizing inflammatory response, infiltrate, retinal injuries with calcification and focal gliosis, renal parenchymal damage and liver lobular inflammation dependent on the dose and time of exposure. However, tissue toxicity and accumulation of SNPs in liver observed at day 10 was greater than at day 60 and much greater than at day 180. In contrast, a dramatic increase in cytokine levels was observed at day 60. Despite the relatively high doses, SNPs did not cause subchronic toxicity at day 180 after single-dose intravenous injection. However, they showed distinct differences in the 60 day in vivo subchronic toxicity and inflammation profile as a function of surface area and size.

Radiation-induced proctitis (RIP) is a debilitating adverse event that occurs commonly during lower abdominal radiotherapy. The lack of prophylactic treatment strategies leads to diminished patient quality of life, disruption of radiotherapy schedules, and limitation of radiotherapy efficacy due to dose-limiting toxicities. Semisynthetic glycosaminoglycan ethers (SAGE) demonstrate protective effects from RIP. However, low residence time in the rectal tissue limits their utility. We investigated controlled delivery of GM-0111, a SAGE analogue with demonstrated efficacy against RIP, using a series of temperature-responsive polymers to compare how distinct phase change behaviors, mechanical properties and release kinetics influence rectal bioaccumulation. Poly(lactic acid)-co-(glycolic acid)-block-poly(ethylene glycol)-block-poly(lactic acid)-co-(glycolic acid) copolymers underwent macroscopic phase separation, expelling >50% of drug during gelation. Poloxamer compositions released GM-0111 cargo within 1 h, while silk-elastinlike copolymers (SELPs) enabled controlled release over a period of 12 h. Bioaccumulation was evaluated using fluorescence imaging and confocal microscopy. SELP-415K, a SELP analogue with 4 silk units, 15 elastin units, and one elastin unit with lysine residues in the monomer repeats, resulted in the highest rectal bioaccumulation. SELP-415K GM-0111 compositions were then used to provide localized protection from radiation induced tissue damage in a murine model of RIP. Rectal delivery of SAGE using SELP-415K significantly reduced behavioral pain responses, and reduced animal mass loss compared to irradiated controls or treatment with traditional delivery approaches. Histological scoring showed RIP injury was ameliorated for animals treated with GM-0111 delivered by SELP-415K. The enhanced bioaccumulation provided by thermoresponsive SELPs via a liquid to semisolid transition improved rectal delivery of GM-0111 to mice and radioprotection in a RIP model.

Therapeutics targeting cell receptors can elicit biological responses in situ. However, the ability to dictate when and where these responses occur is a current challenge. Therapeutic proteins can be combined with stimuli-responsive peptides to increase targeting and stimuli responsive behavior. To this end the authors genetically engineered an elastinlike polypeptide (ELP) fusion protein for selective ELPylation. The addition of a charged, foldable region provides these protein subunits with varied thermoresponsive properties from their parent ELPs. These subunits have responsive secondary structures, dependent on pH, indicating the capability to form coiled-coils with a complementary peptide tag. A Rituximab conjugate is generated herein, containing the complementary peptide. Upon mixing of the ELP and Rituximab subunits, the resulting protein complexes can target CD20 receptors on Raji B cells, resulting in at least twofold increase in mean fluorescent intensities. These ELP subunits fold in vitro with the complimentary generated Rituximab conjugate. This work provides the basis for the design of a therapeutic stimuli-responsive biomacromolecule for targeting receptors.

The extracellular matrix (ECM) plays an active role in cell life through a tightly controlled reciprocal relationship maintained by several fibrous proteins, enzymes, receptors, and other components. It is also highly involved in cancer progression. Because of its role in cancer etiology, the ECM holds opportunities for cancer therapy on several fronts. There are targets in the tumor-associated ECM at the level of signaling molecules, enzyme expression, protein structure, receptor interactions, and others. In particular, the ECM is implicated in invasiveness of tumors through its signaling interactions with cells. By capitalizing on the biology of the tumor microenvironment and the opportunities it presents for intervention, the ECM has been investigated as a therapeutic target, to facilitate drug delivery, and as a prognostic or diagnostic marker for tumor progression and therapeutic intervention. This review summarizes the tumor ECM biology as it relates to drug delivery with emphasis on design parameters targeting the ECM.

BACKGROUND Altered neovascularity is typically observed in chronic inflammatory diseases with overlapping pathophysiology to that observed in chronic rhinosinusitis (CRS). However, characterization of these inflammatory-induced vascular-mediated changes in CRS is limited. Understanding the underlying vascular changes in CRS will allow for strategic design and development of new drug-delivery technologies that exploit vascular permeability for increased extravasation into the target sinonasal tissues. METHODS Patients with CRS with nasal polyps (CRSwNP) and without nasal polyps (CRSsNP) and non-CRS controls were enrolled in this prospective, observational study. The extent of angiogenesis in tissue was characterized using immunohistochemical and multiplex gene expression analyses. Vascular permeability, interendothelial junction structures, and endothelial barrier morphology were evaluated using transmission electron microscopy. RESULTS Sinonasal vascularity was increased significantly in CRSsNP and CRSwNP (p < 0.05) when compared with controls, as assessed by enumerating the platelet endothelial cell adhesion molecule (PECAM-1)-positive blood vessels. Pro-angiogenic gene expression, including PECAM1 and platelet-activating factor receptor, was elevated significantly in patients with CRSwNP when compared with controls (p < 0.05). The fenestration sizes between endothelial cells (17-280 nm) were larger in CRSwNP compared with CRSsNP (10-33 nm) patients and controls (4-12 nm). Global thinning of the endothelial cell lining was observed in CRS patients but not in controls. CONCLUSION Significant increases in vascularity, the pro-angiogenic gene, and protein expression and blood vessel morphogenesis were observed in CRS patients compared with controls. In addition, fenestration sizes between interendothelial junction structures were larger in CRS patients than in controls, suggesting inflammation-driven vascular dysregulation in CRS pathology.

In vitro studies are the first step toward understanding the biological effects of particulate matter. As a more realistic exposure strategy than submerged culture approaches, air-liquid interface (ALI) in vitro exposure systems are gaining interest. One challenge with ALI systems is determining accurate particle mass deposition. Although a few commercially available ALI systems are equipped with online mass deposition monitoring, most studies use indirect methods to estimate mass doses. These different indirect methods may contribute to inconsistencies in the results from in vitro studies of aerosolized nanoparticles. This study explored the effectiveness of using a commercially available Quartz Crystal Microbalance (QCM) to estimate the real-time, particle-mass deposition inside an electrostatic, parallel-flow, ALI system. The QCM system required minor modifications, including custom-designed and fabricated headers. Three QCM systems were simultaneously placed in three of the six wells in the ALI exposure chamber to evaluate the uniformity of particle deposition. The measurements from fluorescein dosimetry and QCM revealed an uneven deposition between these six wells. The performance of the QCM system was also evaluated using two different methods. First, using fluorescein deposition in one well, depositions in three other wells were estimated, which was then compared to the actual QCM readings. Second, using the QCM measured deposition in one well, the deposition in three other wells was estimated and compared to deposition measured by fluorescein dosimetry. For both methods, the expected and actual deposition yields a linear fit with the slope ~1. This good fit suggests that QCM systems can be used to measure real-time mass deposition in an electrostatic ALI system.

Background Chronic inflammation is known to cause alterations in vascular homeostasis that directly affects blood vessel morphogenesis, angiogenesis, and tissue permeability. These phenomena have been investigated and exploited for targeted drug delivery applications in the context of cancers and other disease processes. Vascular pathophysiology and its associated genes and signaling pathways, however, have not been systematically investigated in patients with chronic rhinosinusitis (CRS). Understanding the interplay between key vascular signaling pathways and top biomarkers associated with CRS may facilitate the development of new targeted delivery strategies and treatment paradigms. Herein, we report findings from a gene meta-analysis to identify key vascular pathways and top genes involved in CRS. Methods Proprietary software (Illumina BaseSpace Correlation Engine) and open-access data sets were used to perform a gene meta-analysis to systematically determine significant differences between key vascular biomarkers and vascular signaling pathways expressed in sinonasal tissue biopsies of controls and patients with CRS. Results Thirteen studies were initially identified, and then reduced to five after applying exclusion principle algorithms. Genes associated with vasculature development and blood vessel morphogenesis signaling pathways were identified to be overexpressed among the top 15 signaling pathways. Out of many significantly upregulated genes, the levels of pro angiogenic genes such as early growth response (EGR3), platelet endothelial cell adhesion molecule (PECAM1) and L-selectin (SELL) were particularly significant in patients with CRS compared to controls. Discussion Key vascular biomarkers and signaling pathways were significantly overexpressed in patients with CRS compared to controls, suggesting a contribution of vascular dysfunction in CRS pathophysiology. Vascular dysregulation and permeability may afford opportunities to develop drug delivery systems to improve efficacy and reduce toxicity of CRS treatment.

Silica nanoparticles (SNPs) can cause abnormal spermatogenesis in male reproductive toxicity. However, the toxicity and toxicological mechanisms of SNPs in testosterone synthesis and secretion in Leydig cells are not well known. Therefore, this study aimed to determine the effect and molecular mechanism of low doses of SNPs in testosterone production in Leydig cells. For this, mouse primary Leydig cells (PLCs) were exposed to 100 nm Stöber nonporous spherical SNPs. We observed significant accumulation of SNPs in the cytoplasm of PLCs via transmission electron microscopy (TEM). CCK-8 and flow cytometry assays confirmed that low doses (50 and 100 μg/mL) of SNPs had no significant effect on cell viability and apoptosis, whereas high doses (more than 200 μg/mL) decreased cell viability and increased cell apoptosis in PLCs. Monodansylcadaverine (MDC) staining showed that SNPs caused the significant accumulation of autophagosomes in the cytoplasm of PLCs. SNPs activated autophagy by upregulating microtubule-associated protein light chain 3 (LC3-II) and BCL-2-interacting protein (BECLIN-1) levels, in addition to downregulating sequestosome 1 (SQSTM1/P62) level at low doses. In addition, low doses of SNPs enhanced testosterone secretion and increased steroidogenic acute regulatory protein (StAR) expression. SNPs combined with rapamycin (RAP), an autophagy activator, enhanced testosterone production and increased StAR expression, whereas SNPs combined with 3-methyladenine (3-MA) and chloroquine (CQ), autophagy inhibitors, had an opposite effect. Furthermore, BECLIN-1 depletion inhibited testosterone production and StAR expression. Altogether, our results demonstrate that low doses of SNPs enhanced testosterone secretion via the activation of autophagy in PLCs.

Silica nanoparticles are extensively used in biomedical applications and consumer products. Little is known about the interaction of these NPs with the endothelium and effect on platelet adhesion under flow conditions in circulation. In this study, we investigated the effect of silica nanoparticles on the endothelium and its inflammation, and subsequent adhesion of flowing platelets in vitro. Platelet counts adhered onto the surface of endothelial cells in the presence of nanoparticles increased at both low and high concentrations of nanoparticles. Preincubation of endothelial cells with nanoparticles also increased platelet adhesion. Interestingly, platelet adhesion onto TNF-α-treated endothelial cells decreased in the presence of nanoparticles at different concentrations as compared with the absence of nanoparticles. We monitored the expression of different endothelial proteins, known to initiate platelet adhesion, in the presence and absence of silica nanoparticles. We found that silica nanoparticles caused changes in the endothelium such as overexpression of PECAM that promoted platelet adhesion to the endothelial cell.

Polymeric drug carriers can alter the pharmacokinetics of their drug cargoes, thereby improving drug therapeutic index and reducing side effects. Understanding and controlling polymer properties that drive tissue-specific accumulation is critical in engineering targeted drug delivery systems. For kidney disease applications, targeted drug delivery to renal cells that reside beyond the charge- and size-selective glomerular filtration barrier could have clinical potential. However, there are limited reports on polymer properties that might enhance kidney accumulation. Here, we studied the effects of molecular weight and charge on the in vivo kidney accumulation of polymers in health and disease. We synthesized a panel of well-defined polymers by atom transfer radical polymerization to answer several questions. First, the biodistribution of low molecular weight (23–27 kDa) polymers composed of various ratios of neutral:anionic monomers (1:0, 1:1, 1:4) in normal mice was determined. Then, highly anionic (1:4 monomer ratio) low molecular and high molecular weight (47 kDa) polymers were tested in both normal and experimental focal segmental glomerulosclerosis (FSGS) mice, a model that results in loss of glomerular filtration selectivity. Through these studies, we observed that kidney-specific polymer accumulation increases with anionic monomer content, but not molecular weight; experimental FSGS increases kidney accumulation of anionic polymers; and anionic polymers accumulate predominantly in proximal tubule cells, with some distribution in kidney glomeruli . These findings can be applied to the design of polymeric drug carriers to enhance or mitigate kidney accumulation.

Tunable glutathione (GSH)-sensitive hollow mesoporous silica nanoparticles (HMSiO(2) NPs) were developed using a structural difference-based selective etching strategy. These organosilica hollow nanoparticles contained disulfide linkages (S-S) in the outer shell which were degraded by GSH. The particles were compared with their nonGSH-sensitive tetraethyl orthosilicate (TEOS) HMSiO counterparts in terms of their synthesis method, characterization, DOX release profile, and in vitro cytotoxicity in MCF-7 breast cancer cells. Transmission electron microscopy (TEM) of the particles indicated that the fabricated HMSiO(2)NPs had an average diameter of 130 ± 5 nm. Thermogravimetric analysis (TGA) revealed that GSH-sensitive particles had approximately 5.3% more weight loss than TEOS HMSiO(2) NPs. Zeta potential of these redox-responsive particles was −23 ± 1 mV at pH 6 in deionized (DI) water. Nitrogen adsorption-desorption isotherm revealed that the surface area of the hollow mesoporous nanoreservoirs was roughly 446 ± 6 m(2) g(−1) and the average diameter of the pores was 2.3 ± 0.5 nm. TEM images suggest that the nanoparticles started to lose mass integrity from Day 1. The particles showed a high loading capacity for DOX (8.9 ± 0.5%) as a model drug, due to the large voids existing in the hollow structures. Approximately 58% of the incorporated DOX released within 14 days in phosphate buffered saline (PBS) at pH 6 and in the presence of 10 mM GSH, mimicking intracellular tumor microenvironment while release from TEOS HMSiO(2) NPs was only c.a. 18%. The uptake of these hollow nanospheres by MCF-7 cells and RAW 264.7 macrophages was evaluated using TEM and confocal microscopy. The nanospheres were shown to accumulate in the endolysosomal compartments after incubation for 24 h with the maximum uptake of c.a. 2.1 ± 0.3 % and 5.2 ± 0.4%, respectively. Cytotoxicity of the nanospheres was investigated using CCK-8 assay. Results indicate that intact hollow particles (both GSH-sensitive and TEOS HMSiO(2) NPs) were nontoxic to MCF-7 cells after incubation for 24 h within the concentration range of 0–1000 μg ml(−1). DOX-loaded GSH-sensitive nanospheres containing 6 μg ml(−1) of DOX killed c.a. 51 % of MCF-7 cells after 24 h while TEOS HMSiO(2) NPs killed c.a. 20% with the difference being statistically significant. Finally, cytotoxicity data in RAW 264.7 macrophages and NIH 3T3 fibroblasts shows that intact GSH-sensitive HMSiO(2) NPs did not show any toxic effects on these cells with the concentrations equal or less than 125 μg ml(−1).

Careful evaluation of the toxicological response of engineered nanomaterials (ENMs) as a function of physicochemical properties can aid in the design of safe platforms for biomedical applications including drug delivery. Typically, in vitro ENM cytotoxicity assessments are performed under conventional static cell culture conditions. However, such conditions do not take into account the sedimentation rate of ENMs. Herein, we synthesized four types of similar size silica nanoparticles (SNPs) with modified surface roughness, charge, and density and characterized their cytotoxicity under static and dynamic conditions. Influence of particle density on sedimentation and diffusion velocities were studied by comparing solid dense silica nanoparticles of approximately 350 nm in diameter with hollow rattle shape particles of similar size. Surface roughness and charge had negligible impact on sedimentation and diffusion velocities. Lower cellular uptake and toxicity was observed by rattle particles and under dynamic conditions. Dosimetry of ENMs are primarily reported by particle concentration, assuming homogeneous distribution of nanoparticles in cell culture media. However, under static conditions, nanoparticles tend to sediment at a higher rate due to gravitational forces and hence increase effective doses of nanoparticles exposed to cells. By introducing shear flow to SNP suspensions, we reduced sedimentation and nonhomogeneous particle distribution. These results have implications for design of in vitro cytotoxicity assessment of ENMs and suggest that among other factors, sedimentation of nanoparticles in toxicity assessment should be carefully considered.

Little is known about the global gene expression profile of macrophages in response to changes in size and porosity of silica nanoparticles (SNPs). Spherical nonporous SNPs of two different diameters, and mesoporous spherical SNPs with comparable size were characterized. Reactive oxygen species, mitochondrial membrane potential, lysosome degradation capacity, and lysosome pH were measured to evaluate the influence of nonporous and mesoporous SNPs on mitochondrial and lysosomal function. RNA-sequencing was utilized to generate transcriptional profiles of RAW264.7 macrophages exposed to non-toxic SNP doses. DESeq2, limma, and BinReg2 software were used to analyze the data based on both unsupervised and supervised strategies to identify genes with greatest differences among NP treatments. Utilizing GATHER and DAVID software, possible induced pathways were studied. We found that mesoporous silica nanoparticles are capable of altering gene expression in macrophages at doses that do not elicit acute cytotoxicity, while gene transcription was minimally affected by nonporous SNPs.

Careful assessment of the biological fate and immune response of inorganic nanoparticles is crucial for use of such carriers in drug delivery and other biomedical applications. Many studies have elucidated the cellular and molecular mechanisms of the interaction of inorganic nanoparticles with the components of the immune system. The biodegradation and dissolution of inorganic nanoparticles can influence their ensuing immune response. While the immunological properties of inorganic nanoparticles as a function of their physicochemical properties have been investigated in detail, little attention has been paid to the immune adverse effects towards the degradation products of these nanoparticles. To fill this gap, we herein summarize the cellular mechanisms of immune response to inorganic nanoparticles and their degradation products with specific focus on immune cells. We also accentuate the importance of designing new methods and instruments for the in situ characterization of inorganic nanoparticles in order to assess their safety as a result of degradation. This review further sheds light on factors that need to be considered in the design of safe and effective inorganic nanoparticles for use in delivery of bioactive and imaging agents.

Chronic rhinosinusitis (CRS) is a debilitating inflammatory disorder of the sinonasal mucosa that substantially diminishes patient quality of life. Progress surrounding management of this disease has been crippled by a lack of therapeutic innovation. It has been posited that increased vascularity within the diseased sinuses of patients with CRS may allow for improved systemic drug delivery via nanoscale liposomal carriers. Such a system could enhance drug distribution, accumulation, and retention within the sinuses, ultimately leading to improved patient outcomes. PEGylated liposomes loaded with indocyanine green (ICG) were synthesized, characterized and systemically administered in a mouse model of CRS. Accumulation and retention of ICG in sinonasal tissue were evaluated. Compared to healthy controls, CRS mice showed significant sinonasal tissue accumulation and retention of PEGylated liposomal ICG for up to 21 days (P 0.001). Conversely, free ICG was eliminated from the body after 24 h in both groups.

Radiation-induced proctitis (RIP) is the most common clinical adverse effect for patients receiving radiotherapy as part of the standard course of treatment for ovarian, prostate, colon, and bladder cancers. RIP limits radiation dosage, interrupts treatment, and lowers patients' quality of life. A prophylactic treatment that protects the gastrointestinal tract from deleterious effects of radiotherapy will significantly improve patient quality of life and may allow for higher and more regular doses of radiation therapy. Semi-synthetic glycosaminoglycan (GAG), generated from the sulfation of hyaluronic acid, are anti-inflammatory but have difficulty achieving therapeutic levels in many tissues. To enhance the delivery of GAG, we created an in situ gelling rectal delivery system using silk-elastinlike protein polymers (SELPs). Using solutions of SELP 815K (which contains 6 repeats of blocks comprised of 8 silk-like units, 15 elastin-like units, and 1 lysine-substituted elastin-like unit) with GAG GM-0111, we created an injectable delivery platform that transitioned in

While commonly known for degradation of the extracellular matrix, matrix metalloproteinases (MMPs) exhibit broad potential for use in targeting of bioactive and imaging agents in cancer treatment. MMPs are upregulated at all stages of expression in cancers. A comprehensive analysis of published literature on expression of all MMP subtypes at the genetic, protein, and activity levels in normal and diseased tissues indicate targeting applicability in a variety of cancers. This expression significantly increases at advanced cancer stages, providing an improved opportunity for controlled release in higher-stage patients. Since MMPs are integral at every stage of metastasis, MMP roles in cancer are discussed with a focus on MMP distribution and mobility within cells and tumors for cancer targeting applications. Several strategies for MMP utilization in targeting - such as matrix degradation, MMP cleavage, MMP binding, and MMP-induced environmental changes - are addressed.

Design and development of silica nanoparticles (SiO2 NPs) with a controlled degradation profile promises effective drug delivery with a predetermined carrier elimination profile. In this research, we fabricated a series of redox-responsive polysulfide-based biodegradable SiO2 NPs with low polydispersity and with variations in size (average diameters of 58 ± 7, 108 ± 11, 110 ± 9, 124 ± 9, and 332 ± 6 nm), porosity, and composition (disulfide vs tetrasulfide bonds). The degradation kinetics of the nanoparticles was analyzed in the presence of 8 mM glutathione (GSH), mimicking the intracellular reducing condition. Results indicate that porosity and core composition play the predominant roles in the degradation rate of these nanoparticles. The 108 nm mesoporous disulfide-based nanoparticles showed the highest degradation rate among all the synthesized nanoparticles. Transmission electron microscopy (TEM) reveals that nonporous nanoparticles undergo surface erosion, while porous nanoparticles undergo both surface and bulk erosion under reducing environment. The cytotoxicity of these nanoparticles in RAW 264.7 macrophages was evaluated. Results show that all these nanoparticles with the IC50 values ranging from 233 ± 42 to 705 ± 17 μg mL−1 do not have cytotoxic effect in macrophages at concentrations less than 125 μg mL−1. The degradation products of these nanoparticles collected within 15 days did not show cytotoxicity in the same macrophage cell line after 24 h of incubation. In vitro doxorubicin (DOX) release was examined in 108 nm mesoporous disulfide-based nanoparticles in the absence and presence of 8 mM GSH. It was shown that drug release depends on intracellular reducing conditions. Due to their ease of synthesis and scale up, robust structure, and the ability to control size, composition, release, and elimination, biodegradable SiO2 NPs provide an alternative platform for delivery of bioactive and imaging agents.

Chronic toxicity evaluations of nanotechnology-based drugs are essential to support initiation of clinical trials. Ideally such evaluations should address the dosing strategy in human applications and provide sufficient information for long-term usage. Herein, we investigated one-year toxicity of non-surface modified silica nanoparticles (SNPs) with variations in size and porosity (Stober SNPs 46 ± 4.9 and 432.0 ± 18.7 nm and mesoporous SNPs 466.0 ± 86.0 nm) upon single dose intravenous administration to female and male BALB/c mice (10 animal/sex/group) along with their human blood compatibility. Our evidence of clinical observation and blood parameters showed no significant changes in body weight, cell blood count, nor plasma biomarker indices. No significant changes were noted in post necropsy examination of internal organs and organ-to-body weight ratio. However, microscopic examination revealed significant amount of liver inflammation and aggregates of histocytes with neutrophils within the spleen suggesting an ongoing or resolving injury. The fast accumulation of these plain SNPs in the liver and spleen upon IV administration and the duration needed for their clearance caused these injuries. There were also subtle changes which were attributed to prior infarctions or resolved intravascular thrombosis and included calcifications in pulmonary vessels, focal cardiac fibrosis with calcifications, and focal renal injury. Most of the pathologic lesions were observed when large, non-porous SNPs were administered. Statistically significant chronic toxicity was not observed for the small non-porous particles and for the mesoporous particles. This one-year post-exposure evaluation indicate that female and male BALB/c mice need up to one year to recover from acute tissue toxic effects of silica nanoparticles upon single dose intravenous administration at their 10-day maximum tolerated dose. Further, ex vivo testing with human blood and plasma revealed no hemolysis or complement activation following incubation with these silica nanoparticles. These results can inform the potential utility of silica nanoparticles in biomedical applications such as controlled drug delivery where intravenous injection of the particles is intended.

Silk-elastinlike protein polymers (SELPs) self-assemble into nanostructures when designed with appropriate silk-to-elastin ratios. Here, we investigate the effect of insertion of a matrix metalloproteinase-responsive peptide sequence, GPQGIFGQ, into various locations within the SELP backbone on supramolecular self-assembly. Insertion of the hydrophilic, enzyme-degradable sequence into the elastin repeats allows the formation of dilution-stable nanostructures, while insertion into the hydrophobic silk motifs inhibited self-assembly. The SELP assemblies retained their lower critical solution temperature (LCST) thermal response, allowing up to eightfold volumetric changes due to temperature-induced size change. A model hydrophobic drug was incorporated into SELP nanoassemblies utilising a combination of precipitation, incubation and tangential flow filtration. While the nanoconstructs degraded in response to MMP activity, drug release kinetics was independent of MMP concentration. Drug release modelling suggests that release is driven by rates of water penetration into the SELP nanostructures and drug dissolution. In vitro testing revealed that SELP nanoassemblies reduced the immunotoxic and haemolytic side effects of doxorubicin in human blood while maintaining its cytotoxic activity.

Fundamental to the design and development of nanoparticles for applications in nanomedicine is a detailed understanding of their biologic fate and potential toxic effects. Transient receptor potential (TRP) ion channels are a large superfamily of cation channels with varied physiologic functions. This superfamily is classified into six related subfamilies: TRP canonical, TRP vanilloid (TRPV), TRP melastatin (TRPM), TRP ankyrin (TRPA), TRP polycystin, and TRP mucolipin. TRPA1, TRPM2, and TRPM8 are nonselective Ca(2+)-permeable cation channels which regulate calcium pathways under oxidative stress, whereas TRPV4 can be activated by oxidative, osmotic, and thermal stress as well as different fatty acid metabolites. Using a series of well characterized silica nanoparticles with variations in size (approximately 50–350 nm in diameter) and porosity, as well as cationic and anionic poly(amido amine) (PAMAM) dendrimers of similar size, we examined the toxicity of these nanoparticles to human embryonic kidney-293 cells overexpressing different TRP channels. The data show that the toxicity of mesoporous silica nanoparticles was influenced by expression of the TRPA1 and TRPM2 channels, whereas the toxicity of smaller nonporous silica nanoparticles was only affected by TRPM8. Additionally, TRPA1 and TRPM2 played a role in the cytotoxicity of cationic dendrimers, but not anionic dendrimers. TRPV4 did not seem to play a significant role in silica nanoparticle or PAMAM toxicity.

Rationale: Intraoperative bleeding impairs physicians' ability to visualize the surgical field, leading to increased risk of surgical complications and reduced outcomes. Bleeding is particularly challenging during endoscopic-assisted surgical resection of hypervascular tumors in the head and neck. A tool that controls bleeding while marking tumor margins has the potential to improve gross tumor resection, reduce surgical morbidity, decrease blood loss, shorten procedure time, prevent damage to surrounding tissues, and limit postoperative pain. Herein, we develop and characterize a new system that combines pre-surgical embolization with improved visualization for endoscopic fluorescence image-guided tumor resection. Methods: Silk-elastinlike protein (SELP) polymers were employed as liquid embolic vehicles for delivery of a clinically used near-infrared dye, indocyanine green (ICG). The biophysical properties of SELP, including gelation kinetics, modulus of elasticity, and viscosity, in response to ICG incorporation using rheology, were characterized. ICG release from embolic SELP was modeled in tissue phantoms and via fluorescence imaging. The embolic capability of the SELP-ICG system was then tested in a microfluidic model of tumor vasculature. Lastly, the cytotoxicity of the SELP-ICG system in L-929 fibroblasts and human umbilical vein endothelial cells (HUVEC) was assessed. Results: ICG incorporation into SELP accelerated gelation and increased its modulus of elasticity. The SELP embolic system released 83 ± 8% of the total ICG within 24 hours, matching clinical practice for pre-surgical embolization procedures. Adding ICG to SELP did not reduce injectability, but did improve the gelation kinetics. After simulated embolization, ICG released from SELP in tissue phantoms diffused a sufficient distance to deliver dye throughout a tumor. ICG-loaded SELP was injectable through a clinical 2.3 Fr microcatheter and demonstrated deep penetration into 50-µm microfluidic-simulated blood vessels with durable occlusion. Incorporation of ICG into SELP improved biocompatibility with HUVECs, but had no effect on L-929 cell viability. Principle Conclusions: We report the development and characterization of a new, dual-functional embolization-visualization system for improving fluorescence-imaged endoscopic surgical resection of hypervascular tumors.

Silica nanoparticles (SiO2 NPs) have potential utility in controlled release. Despite significant research in this area, there is a gap in the understanding of the correlation between SiO2 NP physicochemical properties on the one hand and their degradation in solutions, in cells, and in vivo on the other. Here, we fabricated SiO2 NPs with variations in size, porosity, density, and composition: 100 nm Stober, 100 and 500 nm mesoporous, 100 nm disulfide-based mesoporous, and 100 nm disulfide-based hollow mesoporous. Degradation profiles over 28 days were investigated in simulated biological fluids and deionized water. Results show Meso 100, and 500 nanoparticles degraded faster at higher pH values. Results from macrophages indicate Meso 100 nanoparticles showed the highest degradation amount (~3.8%). Cytotoxicity evaluation of the particles in Human Aortal Endothelial Cells (HAECs) shows concentration-dependent toxicity for the particles. Results from CD-1 mice show ~53% of Meso 100 nanoparticles (25 mg kg−1) degraded and were detected in urine after seven days. It was shown nanoparticle porosity and composition as well as pH and ionic strength of the medium play the predominant roles for degradation of SiO2 NPs. Based on histological evaluations, at the injected doses investigated, the particles did not show toxicity.

Introduction: Dendrimers showed promise as carriers for oral delivery due to their nanoscale size and transepithelial permeability across the gut epithelium. However, for the successful approval of dendrimer-based oral therapeutics for human use, it is essential to understand their pharmacokinetics. The knowledge of pharmacokinetics of drugs delivered with dendrimers within the context of oral delivery of therapeutics will help in the design of clinical trials, and development of dosage regimens. Areas covered: This review summarizes the pharmacokinetic aspects of dendrimer and dendrimer-drug complexes after oral administration. We discussed the influence of size, core chemistry, surface charge, surface chemistry, and modification on the pharmacokinetics of dendrimers and dendrimer-drug complexes. Furthermore, we also discussed studies involving alternative dosage forms such as matrix tablets containing dendrimers, dendrimers encapsulated in lipid nanostructures, and chitosan anchored-dendrimers. Expert opinion: From the studies, it is evident that dendrimers significantly improve the oral bioavailability of drugs with poor biopharmaceutical properties. However, further in vivo studies are needed to establish the relationship between the properties of dendrimers and oral pharmacokinetics of dendrimer-drug complexes and conjugates.

In vitro studies are a first step toward understanding the biological effects of combustion-derived particulate matter (cdPM). A vast majority of studies expose cells to cdPM suspensions, which requires a method to collect cdPM and suspend it in an aqueous media. The consequences of different particle collection methods on particle physiochemical properties and resulting biological responses are not fully understood. This study investigated the effect of two common approaches (collection on a filter and a cold plate) and one relatively new (direct bubbling in DI water) approach to particle collection. The three approaches yielded cdPM with differences in particle size distribution, surface area, composition, and oxidative potential. The directly bubbled sample retained the smallest sized particles and the bimodal distribution observed in the gas-phase. The bubbled sample contained ∼50% of its mass as dissolved species and lower molecular weight compounds, not found in the other two samples. These differences in the cdPM properties affected the biological responses in THP-1 cells. The bubbled sample showed greater oxidative potential and cellular reactive oxygen species. The scraped sample induced the greatest TNFα secretion. These findings have implications for in vitro studies of air pollution and for efforts to better understand the underlying mechanisms.

Inorganic nanoparticles provide the opportunity to localize bioactive agents to the target sites and protect them from degradation. In many cases, acute toxicities of inorganic nanoparticles used for delivery applications have been investigated. However, little information is available regarding the long-term toxicity of such materials. This review focuses on the importance of subchronic and chronic toxicity assessment of inorganic nanoparticles investigated for delivery applications. We have attempted to provide a comprehensive review of the available literature for chronic toxicity assessment of inorganic nanoparticles. Where possible correlations are made between particle composition, physiochemical properties, duration, frequency and route of administration, as well as the sex of animals, with tissue and blood toxicity, immunotoxicity and genotoxicity. A critical gap analysis is provided and important factors that need to be considered for long-term toxicology of inorganic nanoparticles are discussed.

Interstitial cystitis (IC), also known as painful bladder syndrome, is a debilitating chronic condition with many patients failing to respond to current treatment options. Rapid clearance, mucosal coating, and tight epithelium create strong natural barriers that reduce the effectiveness of many pharmacological interventions in the bladder. Intravesical drug delivery (IDD) is the administration of therapeutic compounds or devices to the urinary bladder via a urethral catheter. Previous work in improving IDD for IC has focused on the sustained delivery of analgesics within the bladder and other small molecule drugs which do not address underlying inflammation and bladder damage. Therapeutic glycosaminoglycans (GAG) function by restoring the mucosal barrier within the bladder, promoting healing responses, and preventing irritating solutes from reaching the bladder wall. There is an unmet medical need for a therapy that provides both acute relief of symptoms while alleviating underlying physiological sources of inflammation and promoting healing within the urothelium. Semi-synthetic glycosaminoglycan ethers (SAGE) are an emerging class of therapeutic GAG with intrinsic anti-inflammatory and analgesic properties. To reduce SAGE clearance and enhance its accumulation in the bladder, we developed a silk-elastinlike protein polymer (SELP) based system to enhance SAGE IDD. We evaluated in vitro release kinetics, rheological properties, impact on bladder function, pain response, and bladder inflammation and compared their effectiveness to other temperature-responsive polymers including Poloxamer 407 and poly(lactic-co-glycolic acid)-poly(ethylene glycol). SAGE delivered via SELP-enhanced intravesical delivery substantially improved SAGE accumulation in the urothelium, provided a sustained analgesic effect 24 h after administration, and reduced inflammation.

An ‘on-demand’ drug release and ROS-responsive nanoparticle was prepared by chemically conjugating hydrophobic α-tocopheryl succinate to hydrophilic poly(ethylene glycol) via a thioketal linker. This nanoparticle encapsulated with doxorubicin and α-tocopheryl succinate exhibited remarkable efficiency in reversing multidrug resistance both in vitro and in vivo.

Polymeric matrices inherently protect viral vectors from pre-existing immune conditions, limit dissemination to off-target sites, and can sustain vector release. Advancing methodologies in development of particulate based vehicles have led to improved encapsulation of viral vectors. Polymeric delivery systems have contributed to increasing cellular transduction, responsive release mechanisms, cellular infiltration, and cellular signaling. Synthetic polymers are easily customizable, and are capable of balancing matrix retention with cellular infiltration. Natural polymers contain inherent biorecognizable motifs adding therapeutic efficacy to the incorporated viral vector. Recombinant polymers use highly conserved motifs to carefully engineer matrices, allowing for precise design including elements of vector retention and responsive release mechanisms. Composite polymer systems provide opportunities to create matrices with unique properties. Carefully designed matrices can control spatiotemporal release patterns that synergize with approaches in regenerative medicine and antitumor therapies.