Search

An approach to differentially modify the internal surface of porous silicon nanoparticles (pSiNPs) with hydrophobic dodecene and the external surface with antifouling poly

The androgen receptor (AR) is the key oncogenic driver of prostate cancer, and despite implementation of novel AR targeting therapies, outcomes for metastatic disease remain dismal. There is an urgent need to better understand androgen-regulated cellular processes to more effectively target the AR dependence of prostate cancer cells through new therapeutic vulnerabilities. Transcriptomic studies have consistently identified lipid metabolism as a hallmark of enhanced AR signaling in prostate cancer, yet the relationship between AR and the lipidome remains undefined. Using mass spectrometry–based lipidomics, this study reveals increased fatty acyl chain length in phospholipids from prostate cancer cells and patient-derived explants as one of the most striking androgen-regulated changes to lipid metabolism. Potent and direct AR-mediated induction of ELOVL fatty acid elongase 5 (ELOVL5), an enzyme that catalyzes fatty acid elongation, was demonstrated in prostate cancer cells, xenografts, and clinical tumors. Assessment of mRNA and protein in large-scale data sets revealed ELOVL5 as the predominant ELOVL expressed and upregulated in prostate cancer compared with nonmalignant prostate. ELOVL5 depletion markedly altered mitochondrial morphology and function, leading to excess generation of reactive oxygen species and resulting in suppression of prostate cancer cell proliferation, 3D growth, and in vivo tumor growth and metastasis. Supplementation with the monounsaturated fatty acid cis-vaccenic acid, a direct product of ELOVL5 elongation, reversed the oxidative stress and associated cell proliferation and migration effects of ELOVL5 knockdown. Collectively, these results identify lipid elongation as a protumorigenic metabolic pathway in prostate cancer that is androgen-regulated, critical for metastasis, and targetable via ELOVL5.Significance:This study identifies phospholipid elongation as a new metabolic target of androgen action that is critical for prostate tumor metastasis.

Supplementary figures 1-9 and legends.

Quantum-sized gold nanoclusters (AuNCs) are emerging as theranostic agents-those that combine diagnostics and therapeutic properties-given their ultrasmall size

The androgen receptor (AR) is the key oncogenic driver of prostate cancer, and despite implementation of novel AR targeting therapies, outcomes for metastatic disease remain dismal. There is an urgent need to better understand androgen-regulated cellular processes to more effectively target the AR dependence of prostate cancer cells through new therapeutic vulnerabilities. Transcriptomic studies have consistently identified lipid metabolism as a hallmark of enhanced AR signaling in prostate cancer, yet the relationship between AR and the lipidome remains undefined. Using mass spectrometry–based lipidomics, this study reveals increased fatty acyl chain length in phospholipids from prostate cancer cells and patient-derived explants as one of the most striking androgen-regulated changes to lipid metabolism. Potent and direct AR-mediated induction of ELOVL fatty acid elongase 5 (ELOVL5), an enzyme that catalyzes fatty acid elongation, was demonstrated in prostate cancer cells, xenografts, and clinical tumors. Assessment of mRNA and protein in large-scale data sets revealed ELOVL5 as the predominant ELOVL expressed and upregulated in prostate cancer compared with nonmalignant prostate. ELOVL5 depletion markedly altered mitochondrial morphology and function, leading to excess generation of reactive oxygen species and resulting in suppression of prostate cancer cell proliferation, 3D growth, and in vivo tumor growth and metastasis. Supplementation with the monounsaturated fatty acid cis-vaccenic acid, a direct product of ELOVL5 elongation, reversed the oxidative stress and associated cell proliferation and migration effects of ELOVL5 knockdown. Collectively, these results identify lipid elongation as a protumorigenic metabolic pathway in prostate cancer that is androgen-regulated, critical for metastasis, and targetable via ELOVL5. Significance: This study identifies phospholipid elongation as a new metabolic target of androgen action that is critical for prostate tumor metastasis.

We introduce xanthate-functionalized poly(cyclic imino ethers)s (PCIEs), specifically poly(2-ethyl-2-oxazoline) and poly(2-ethyl-2-oxazine) given their stealth characteristics, as an attractive alternative to conventional thiol-based ligands for the synthesis of highly monodisperse and fluorescent gold nanoclusters (AuNCs). The xanthate in the PCIEs interacts with Au ions, acting as a well-controlled template for the direct formation of PCIE-AuNCs. This method yields red-emitting AuNCs with a narrow emission peak (λem = 645 nm), good quantum yield (4.3-4.8%), long fluorescence decay time (∼722-844 ns), and unprecedented product yield (>98%). The PCIE-AuNCs exhibit long-term colloidal stability, biocompatibility, and antifouling properties, enabling a prolonged blood circulation, lower nonspecific accumulation in major organs, and better renal clearance when compared with AuNCs without polymer coating. The advances made here in the synthesis of metal nanoclusters using xanthate-functionalized PCIEs could propel the production of highly monodisperse, biocompatible, and renally clearable nanoprobes in large-scale for different theranostic applications.

Induced tolerogenic dendritic cells are a powerful immunotherapy for autoimmune disease that have shown promise in laboratory models of disease and early clinical trials. In contrast to conventional immunosuppressive treatments, tolerogenic immunotherapy leverages the cells and function of the immune system to quell the autoreactive lymphocytes responsible for damage and disease. The principle techniques of isolating and reprogramming dendritic cells (DCs), central to this approach, are well characterized. However, the broader application of this technology is limited by its high cost and bespoke nature. Nanomedicine offers an alternative route by performing this reprogramming process in situ. Here, we review the challenges and opportunities in using nanoparticles as a delivery mechanism to target DCs and induce immunomodulation, emphasizing their versatility. We then highlight their potential to solve critical problems in organ transplantation and increasingly prevalent autoimmune disorders such as type 1 diabetes mellitus and multiple sclerosis, where new immunotherapy approaches have begun to show promise. Tolerogenic dendritic cells inhibit inflammatory responses against self-antigens, offering a therapeutic strategy for autoimmune diseases. This Review describes the nanotechnology-based approaches available to target dendritic cells and induce tolerogenic properties, highlighting applications in organ transplantation, multiple sclerosis and diabetes mellitus.

Engineered nano–bio interfaces–driven by vertical micro/nanoneedles, nanoparticles, organ‐on‐chip devices, and a diversity of nanosubstrates for mass spectroscopy imaging–are spurring scientific and technological progress, from fundamental to transnational biomedical research. Each class has its own characteristic features, which is critical for their translational uptake, but they broadly share the same range of functionality and applicability at the forefront of modern research and medicine. The review provides insights into unique attributes of microneedle technology and its ability for efficient transdermal transport of therapeutic compounds. The uses of nanoneedle technology in precise manipulation of increasingly complex cellular processes at the cell–material interface and their potential for major improvements for many fundamental research applications and ex vivo cell‐based therapies are highlighted. A snapshot in the use of food and drug administration (FDA)‐approved nanoparticle therapeutics and their applications in nanomedicine is provided. The achievements in organ‐on‐chip technology, particularly at the preclinical stage, and its potential to efficiently screen diverse types of therapeutics are covered. The final section is dedicated to the use of nanomaterial‐enhanced mass spectrometry in drug discovery and imaging. Overall, this review aims to highlight those main rules in the design of bio–nano interfaces that have successfully achieved translation into the market.

The use of protein templates for the controlled synthesis of inorganic nanostructures has gained considerable attention in multidisciplinary fields, including electronics, optics, energy, sensing, and biomedicine, owing to their biocompatibility and structural programmability. The possible synergistic combination of protein scaffolds (and other biomolecules/biopolymers) with metal nanoclusters (MNCs) has created a new class of highly photoluminescent nanoprobes and nanodevices. For the first time, we will discuss the different types of protein templates used for MNC preparation with an emphasis on their optoelectronic properties for application. In particular, applications of protein-coated MNCs for chemosensing or biosensing of cancer biomarkers, neurotransmitters, pathogenic microorganisms, biomolecules, pharmaceutical compounds, and immunoassays are discussed in detail herein. Fluorescence-based and multimodal molecular imaging, both in vitro and in vivo based on functional proteins are also covered. Furthermore, we discuss the burgeoning growth of protein-coated MNCs (e.g., gold (Au) and silver (Ag) NCs) to develop synergistic nanotherapeutics with potential biomedical applications in chemotherapy, radiotherapy, photodynamic therapy (PDT), photothermal therapy (PTT), and antibacterial activity, as well as MNC-containing nanocomposites for enhanced bioimaging and controlled drug release. Overall, the proposed review highlights the recent progress, technical challenges and new horizons in this field, and summarizes our understanding of how MNC properties interact with the biological function of protein scaffolds to develop synergistic nanotherapeutics towards clinical translation.

Over the last thirty years, research in nanomedicine has widely been focused on applications in cancer therapeutics. However, despite the plethora of reported nanoscale drug delivery systems that can successfully eradicate solid tumor xenografts in vivo, many of these formulations have not yet achieved clinical translation. This issue particularly pertains to the delivery of small interfering RNA (siRNA), a highly attractive tool for selective gene targeting. One of the likely reasons behind the lack of translation is that current in vivo models fail to recapitulate critical elements of clinical solid tumors that may influence drug response, such as cellular heterogeneity in the tumor microenvironment. This study incorporates a more clinically relevant model for assessing siRNA delivery systems; ex vivo culture of prostate cancer harvested from patients who have undergone radical prostatectomy, denoted patient-derived explants (PDE). The model retains native human tissue architecture, microenvironment, and cell signaling pathways. Porous silicon nanoparticles (pSiNPs) behavior in this model is investigated and compared with commonly used 3D cancer cell spheroids for their efficacy in the delivery of siRNA directed against the androgen receptor (AR), a key driver of prostate cancer.

Targeted delivery of chemotherapeutics to cancer cells has the potential to yield high drug concentrations in cancer cells while minimizing any unwanted side effects. However, the development of multidrug resistance in cancer cells may impede the accumulation of chemotherapy drugs within these, decreasing its therapeutic efficacy. Downregulation of multidrug resistance-related proteins such as MRP1 with small interfering RNA (siRNA) is a promising approach in the reversal of drug resistance. The co-delivery of doxorubicin (Dox) and siRNA against MRP1 (siMRP1) by using nanoparticles comprised of biocompatible porous silicon (pSi) presents itself as a novel opportunity to utilize the biomaterial's high loading capacity and large accessible surface area. Additionally, to increase the selectivity and retention of the delivery vehicle at the tumor site, nanobodies were incorporated onto the nanoparticle surface via a polyethylene glycol (PEG) linker directed towards either the epidermal growth factor receptor (EGFR) or the prostate specific membrane antigen (PSMA). The nanobody-displaying pSi nanoparticles (pSiNPs) demonstrated effective gene silencing, inhibiting MRP1 expression by 74 ± 6% and 74 ± 4% when incubated with EGFR-pSiNPs and PSMA-pSiNPs, respectively, in prostate cancer cells. The downregulation of MRP1 led to a further increase in cytotoxicity when both siRNA and Dox were delivered in conjunction in both cancer cell monocultures and spheroids when compared to free Dox or Dox and a scrambled sequence of siRNA. Altogether, nanobody-displaying pSiNPs are an effective carrier for the dual delivery of both siRNA and Dox for cancer treatment.

Continuing our research efforts in developing mesoporous silicon nanoparticle-based biomaterials for cancer therapy, we employed here porous silicon nanoparticles as a nanocarrier to deliver contrast agents to diseased cells. Nanoconfinement of small molecule Gd-chelates (L1-Gd) enhanced the T 1 contrast dramatically compared to distinct Gd-chelate (L1-Gd) by virtue of its slow tumbling rate, increased number of bound water molecules, and their occupancy time. The newly synthesized Gd-chelate (L1-Gd) was covalently grafted on silicon nanostructures and conjugated to an antibody specific for epidermal growth factor receptor (EGFR) via a hydrazone linkage. The salient feature of this nanosized contrast agent is the capability of EGFR targeted delivery to cancer cells. Mesoporous silicon nanoparticles were chosen as the nanocarrier because of their high porosity, high surface area, and excellent biodegradability. This type of nanosized contrast agent also performs well in high magnetic fields. Refereed/Peer-reviewed

Gold nanoclusters (Au NCs) have become a promising nanomaterial for cancer therapy because of their biocompatibility and fluorescent properties. In this study, the effect of ultrasmall protein-stabilized 2 nm Au NCs on six types of mammalian cells (fibroblasts, B-lymphocytes, glioblastoma, neuroblastoma, and two types of prostate cancer cells) under electromagnetic radiation is investigated. Cellular association of Au NCs in vitro is concentration-dependent, and Au NCs have low intrinsic toxicity. However, when Au NC-incubated cells are exposed to a 1 GHz electromagnetic field (microwave radiation), cell viability significantly decreases, thus demonstrating that Au NCs exhibit specific microwave-dependent cytotoxicity, likely resulting from localized heating. Upon i.v. injection in mice, Au NCs are still present at 24 h post administration. Considering the specific microwave-dependent cytotoxicity and low intrinsic toxicity, our work suggests the potential of Au NCs as effective and safe nanomedicines for cancer therapy. Refereed/Peer-reviewed

Gene therapy has arisen as a pioneering technique to treat diseases by direct employment of nucleic acids as medicine. The major historical problem is to develop efficient and safe systems for the delivery of therapeutic genes into the target cells. Carbon nanotubes (CNTs) have demonstrated considerable promise as delivery vectors due to their (i) high aspect ratio and (ii) capacity to translocate through plasma membranes, known as the nanoneedle effect. To leverage these advantages, close attention needs to be paid to the physicochemical characteristics of the CNTs used. CNTs with different diameters (thinner and thicker) were treated by chemical oxidation to produce shorter fragments. Rigid (thick) and flexible (thin) CNTs, and their shortened versions, were coated with polyallylamine (ppAA) by plasma-enhanced chemical vapor deposition. The ppAA coating leads to a positively charged CNT surface that is able to electrostatically bind the green fluorescent protein plasmid reporter. This study shows how rigidity and length can affect their (i) behavior in biological media, (ii) ability to transfect in vitro, and (iii) biodistribution in vivo. This study also generates a set of basic design rules for the development of more efficient CNT-based gene-delivery vectors.

Gene silencing by RNA interference is a powerful technology with broad applications. However, this technology has been hampered by the instability of small interfering RNA (siRNA) molecules in physiological conditions and their inefficient delivery into the cytoplasm of target cells. Porous silicon nanoparticles have emerged as a potential delivery vehicle to overcome these limitations-being able to encapsulate RNA molecules within the porous matrix and protect them from degradation. Here, key variables were investigated that influence siRNA loading into porous silicon nanoparticles. The effect of modifying the surface of porous silicon nanoparticles with various amino-functional molecules as well as the effects of salt and chaotropic agents in facilitating siRNA loading was examined. Maximum siRNA loading of 413 μg/(mg of porous silicon nanoparticles) was found when the nanoparticles were modified by a fourth generation polyamidoamine dendrimer. Low concentrations of urea or salt increased loading capacity: an increase in RNA loading by 19% at a concentration of 0.05 M NaCl or 21% at a concentration of 0.25 M urea was observed when compared to loading in water. Lastly, it was demonstrated that dendrimer-functionalized nanocarriers are able to deliver siRNA against ELOVL5, a target for the treatment of advanced prostate cancer.

In advanced breast cancer (BCa) patients, not the primary tumor, but the development of distant metastases, which occur mainly in the organ bone, and their adverse health effects are responsible for high mortality. Targeted delivery of already known drugs which displayed potency, but rather unfavorable pharmacokinetic properties, might be a promising approach to overcome the current limitations of metastatic BCa therapy. Camptothecin (CPT) is a highly cytotoxic chemotherapeutic compound, yet poorly water-soluble and non-specific. Here, CPT was loaded into porous silicon nanoparticles (pSiNP) displaying the epidermal growth factor receptor (EGFR)-targeting antibody (Ab) cetuximab to generate a soluble and targeted nanoscale delivery vehicle for cancer treatment. After confirming the cytotoxic effect of targeted CPT-loaded pSiNP in vitro on MDA-MB-231BO cells, nanoparticles were studied in a humanized BCa bone metastasis mouse model. Humanized tissue-engineered bone constructs (hTEBCs) provided a humanized microenvironment for BCa bone metastases in female NOD-scid IL2Rgnull (NSG) mice. Actively targeted CPT-loaded pSiNP led to a reduction of orthotopic primary tumor growth, increased survival rate and significant decrease in hTEBC and murine lung, liver and bone metastases. This study demonstrates that targeted delivery via pSiNP is an effective approach to employ CPT and other potent anti-cancer compounds with poor pharmacokinetic profiles in cancer therapy.

We demonstrate microwave-induced heating of gold nanoparticles and nanorods. An appreciably higher and concentration-dependent microwave-induced heating rate was observed with aqueous dispersions of the nanomaterials as opposed to pure water and other controls. Grafted with the thermoresponsive polymer poly(N-isopropylacrylamide), these gold nanomaterials react to microwave-induced heating with a conformational change in the polymer shell, leading to particle aggregation. We subsequently covalently immobilize concanavalin A (Con A) on the thermoresponsive gold nanoparticles. Con A is a bioreceptor commonly used in bacterial sensors because of its affinity for carbohydrates on bacterial cell surfaces. The microwave-induced thermal transitions of the polymer reversibly switch on and off the display of Con A on the particle surface and hence the interactions of the nanomaterials with carbohydrate-functionalized surfaces. This effect was determined using linear sweep voltammetry on a methyl-α-d-mannopyranoside-functionalized electrode. Refereed/Peer-reviewed

In order to address the issue of pathogenic bacterial colonization of diabetic wounds, a more direct and robust approach is required, which relies on a physical form of bacterial destruction in addition to the conventional biochemical approach (i.e., antibiotics). Targeted bacterial destruction through the use of photothermally active nanomaterials has recently come into the spotlight as a viable approach to solving the rising problem of antibiotic resistant microorganisms. Materials with high absorption coefficients in the near-infrared (NIR) region of the electromagnetic spectrum show promise as alternative antibacterial therapeutic agents, since they preclude the development of bacterial resistance and can be activated on demand. Here were report on a novel approach for the fabrication of gold nanoparticle decorated porous silicon nanopillars with tunable geometry that demonstrate excellent photothermal conversion properties when irradiated with a 808 nm laser. These photothermal antibacterial properties are demonstrated in vitro against the Gram-positive bacteria Staphylococcus aureus (S. aureus) and Gram-negative Escherichia coli (E. coli). Results show a reduction in bacterial viability of up to 99% after 10 min of laser irradiation. We also show an increase in antibacterial performance after modifying the nanopillars with S. aureus targeting antibodies causing up to a 10-fold increase in bactericidal efficiency compared to E. coli. In contrast, the nanomaterial resulted in minimal disruption of metabolic processes in human foreskin fibroblasts (HFF) after an equivalent period of irradiation. Refereed/Peer-reviewed

There is a strong demand for techniques that allow the fabrication of biocompatible porous nanoparticles for drug delivery applications. In this work, a new method to fabricate size- and shape-controlled porous silicon (pSi) nanodiscs is described. The process relies on a combination of colloidal lithography and metal-assisted chemical etching. Height and diameter of the pSi nanodiscs can be easily adjusted. The nanodiscs are degradable in physiological milieu and are nontoxic to mammalian cells. In order to highlight the potential of the pSi nanodiscs in drug delivery, an in vitro investigation that involved loading of nanodiscs with the anticancer agent camptothecin and functionalization of the nanodisc periphery with an antibody that targets receptors on the surface of neuroblastoma cells is carried out. The thus-prepared nanocarriers are found to selectively attach to and kill cancer cells Refereed/Peer-reviewed

Despite promising advantages, the use of carbon nanotubes (CNTs) for biomedical applications is limited due to their low biocompatibility. This study presents the modification of CNTs by plasma polymerization using two different monomers, pentafluorophenyl methacrylate (PFM) and allylamine (AA). We demonstrated that both type of monomers could be polymerized on the CNT surface in a home-built plasma reactor, allowing the formation of CNT-mediated gene delivery vectors. Once polymerized, such polymers provide different properties to the CNT surface enabling the covalent immobilization of the therapeutic gene or its binding through ionic interaction, respectively.

Supporting Information Available: DNA loadings, release, and UV vis spectra. This material is available free of charge via the Internet at http://pubs.acs.org. We manipulate the passive release rates of DNA payloads on protein coronas formed around nanoparticles (NPs) by varying the corona composition. The coronas are prepared using amixture of hard and soft corona proteins. We form coronas around gold nanorods (NRs), nanobones (NBs), and carbon nanotubes (CNTs) from human serum(HS) and find that tuning the amount of human serum albumin (HSA) in the NR-coronas (NR-HS-DNA) changes the payload release profile. The effect of buffer strength, HS concentration, and concentration of the cetyltrimethylammonium bromide (CTAB) passivating the NP surfaces on passive release is explored. We find that corona properties play an important role in passive release, and concentrations of CTAB, HS, and phosphate buffer used in corona formation can tune payload release profiles. These advances in understanding protein corona properties bring us closer toward developing a set of basic design rules that enable their manipulation and optimization for particular biological applications. Refereed/Peer-reviewed

Blood clotting is a precise cascade engineered to form a clot with temporal and spatial control. Current control of blood clotting is achieved predominantly by anticoagulants and thus inherently one-sided. Here we use a pair of nanorods (NRs) to provide a two-way switch for the blood clotting cascade by utilizing their ability to selectively release species on their surface under two different laser excitations. We selectively trigger release of a thrombin binding aptamer from one nanorod, inhibiting blood clotting and resulting in increased clotting time. We then release the complementary DNA as an antidote from the other NR, reversing the effect of the aptamer and restoring blood clotting. Thus, the nanorod pair acts as an on/off switch. One challenge for nanobiotechnology is the bio-nano interface, where coronas of weakly adsorbed proteins can obscure biomolecular function. We exploit these adsorbed proteins to increase aptamer and antidote loading on the nanorods., National Science Foundation (U.S.) (Grant DMR #0906838)