Targeted drug-loaded PLGA-PCL microspheres for specific and localized treatment of triple negative breast cancer.

The paper presents the results of the experimental and analytical study of targeted drug-loaded polymer-based microspheres made from blend polymer of polylactic-co-glycolic acid and polycaprolactone (PLGA-PCL) for targeted and localized cancer drug delivery. In vitro sustained release with detailed thermodynamically driven drug release kinetics, over a period of three months using encapsulated targeted drugs (prodigiosin-EphA2 or paclitaxel-EphA2) and control drugs [Prodigiosin (PGS), and paclitaxel (PTX)] were studied. Results from in vitro study showed a sustained and localized drug release that is well-characterized by non-Fickian Korsmeyer-Peppas kinetics model over the range of temperatures of 37 °C (body temperature), 41 °C, and 44 °C (hyperthermic temperatures). The in vitro alamar blue, and flow cytometry assays in the presence of the different drug-loaded polymer formulations resulted to cell death and cytotoxicity that was evidence through cell inhibition and late apoptosis on triple negative breast cancer (TNBC) cells (MDA-MB 231). In vivo studies carried out on groups of 4-week-old athymic nude mice that were induced with subcutaneous TNBC, showed that the localized release of the EphA2-conjugated drugs was effective in complete elimination of residual tumor after local surgical resection. Finally, ex vivo histopathological analysis carried out on the euthanized mice revealed no cytotoxicity and absence of breast cancer metastases in the liver, kidney, and lungs 12 weeks after treatment. The implications of the results are then discussed for the development of encapsulated EphA2-conjugated drugs formulation in the specific targeting, localized, and sustain drug release for the elimination of local recurred TNBC tumors after surgical resection.

Shear Assay Protocol for the Determination of Single-Cell Material Properties.

Irregular biomechanics are a hallmark of cancer biology subject to extensive study. The mechanical properties of a cell are similar to those of a material. A cell's resistance to stress and strain, its relaxation time, and its elasticity are all properties that can be derived and compared to other types of cells. Quantifying the mechanical properties of cancerous (malignant) versus normal (non-malignant) cells allows researchers to further uncover the biophysical fundamentals of this disease. While the mechanical properties of cancer cells are known to consistently differ from the mechanical properties of normal cells, a standard experimental procedure to deduce these properties from cells in culture is lacking. This paper outlines a procedure to quantify the mechanical properties of single cells in vitro using a fluid shear assay. The principle behind this assay involves applying fluid shear stress onto a single cell and optically monitoring the resulting cellular deformation over time. Cell mechanical properties are subsequently characterized using digital image correlation (DIC) analysis and fitting an appropriate viscoelastic model to the experimental data generated from the DIC analysis. Overall, the protocol outlined here aims to provide a more effective and targeted method for the diagnosis of difficult-to-treat cancers.

Self-organized mycelium biocomposites: Effects of geometry and laterite composition on compressive behavior.

This study investigates the compressive deformation and the effect of structural architecture on the compressive strength of bioprocessed mycelium biocomposites reinforced with laterite particles. In the mycelium blocks, lignocellulosic hemp hurds function as reinforcing and nutritional substrates. The mycelium acts as a supportive matrix, binding the hemp hurds and the laterite particles which are integrated for further reinforcement to improve the compressive strength of the composite. The compressive behavior of the composites is elucidated using a combined approach of experimental and theoretical studies. The deformation mechanisms are investigated via in-situ observations of the specimens under uniaxial compressive loading. The experiments show that the compressive deformation results in progressive micro-buckling in slender specimens, whereas thicker samples exhibit a soft elastic response at small strain levels followed by continuous stiffening at larger strains. Based on the experimental observations and the morphological characterization, a column buckling analysis was developed for the mycelium-hemp composites to further explain the observed deformation phenomena.

Sustained release of alpha-methylacyl-CoA racemase (AMACR) antibody-conjugated and free doxorubicin from silica nanoparticles for prostate cancer cell growth inhibition.

This article presents silica nanoparticles for the sustained release of AMACR antibody-conjugated and free doxorubicin (DOX) for the inhibition of prostate cancer cell growth. Inorganic MCM-41 silica nanoparticles were synthesized, functionalized with phenylboronic acid groups (MCM-B), and capped with dextran (MCM-B-D). The nanoparticles were then characterized using Fourier-transform infrared spectroscopy, scanning electron microscopy, transmission electron microscopy, zeta potential analysis, nitrogen sorption, X-ray diffraction, and thermogravimetric analysis, before exploring their potential for drug loading and controlled drug release. This was done using a model prostate cancer drug, DOX, and a targeted prostate cancer drug, α-Methyl Acyl-CoA racemase (AMACR) antibody-conjugated DOX, which attaches specifically to AMACR proteins that are overexpressed on the surfaces of prostate cancer cells. The kinetics of sustained drug release over 30 days was then studied using zeroth order, first order, second order, Higuchi, and the Korsmeyer-Peppas models, while the thermodynamics of drug release was elucidated by determining the entropy and enthalpy changes. The flux of the released DOX was also simulated using the COMSOL Multiphysics software package. Generally, the AMACR antibody-conjugated DOX drug-loaded nanoparticles were more effective than the free DOX drug-loaded formulations in inhibiting the growth of prostate cancer cells in vitro over a 96 h period. The implications of the results are then discussed for the development of drug-eluting structures for the localized and targeted treatment of prostate cancer.

Adhesion of LHRH/EphA2 to human Triple Negative Breast Cancer tissues.

The adhesive interactions between molecular recognition units (such as specific peptides and antibodies) and antigens or other receptors on the surfaces of tumors are of great value in the design of targeted nanoparticles and drugs for the detection and treatment of specific cancers. In this paper, we present the results of a combined experimental and theoretical study of the adhesion between Luteinizing Hormone Releasing Hormone (LHRH)/Epherin type A2 (EphA2)-AFM coated tips and LHRH/EphA2 receptors that are overexpressed on the surfaces of human Triple Negative Breast Cancer (TNBC) tissues of different histological grades. Following a histochemical and immuno-histological study of human tissue extracts, the receptor overexpression, and their distributions are characterized using Immunohistochemistry (IHC), Immunofluorescence (IF), and a combination of fluorescence microscopy and confocal microscopy. The adhesion forces between LHRH or EphA2 and human TNBC breast tissues are measured using force microscopy techniques that account for the potential effects of capillary forces due to the presence of water vapor. The corresponding adhesion energies are also determined using adhesion theory. The pull off forces and adhesion energies associated with higher grades of TNBC are shown to be greater than those associated with normal/non-tumorigenic human breast tissues, which were studied as controls. The observed increase in adhesion forces and adhesion energies are also correlated with the increasing incidence of LHRH/EphA2 receptors at higher grades of TNBC. The implications of the results are discussed for the development of targeted nanostructures for the detection and treatment of TNBC.

Effects of polyethylene oxide particles on the photo-physical properties and stability of FA-rich perovskite solar cells.

In this paper, we use Polyethylene Oxide (PEO) particles to control the morphology of Formamidinium (FA)-rich perovskite films and achieve large grains with improved optoelectronic properties. Consequently, a planar perovskite solar cell (PSC) is fabricated with additions of 5 wt% of PEO, and the highest PCE of 18.03% was obtained. This solar cell is also shown to retain up to 80% of its initial PCE after about 140 h of storage under the ambient conditions (average relative humidity of 62.5 ± 3.25%) in an unencapsulated state. Furthermore, the steady-state PCE of the PEO-modified PSC device remained stable for long (over 2500 s) under continuous illumination. This addition of PEO particles is shown to enable the tuning of the optoelectronic properties of perovskite films, improvements in the overall photophysical properties of PSCs, and an increase in resistance to the degradation of PSCs.

Laser-induced heating of polydimethylsiloxane-magnetite nanocomposites for hyperthermic inhibition of triple-negative breast cancer cell proliferation.

This paper presents the results of an experimental and computational study of the effects of laser-induced heating provided by magnetite nanocomposite structures that are being developed for the localized hyperthermic treatment of triple-negative breast cancer. Magnetite nanoparticle-reinforced polydimethylsiloxane (PDMS) nanocomposites were fabricated with weight percentages of 1%, 5%, and 10% magnetite nanoparticles. The nanocomposites were exposed to incident Near Infrared (NIR) laser beams with well-controlled powers. The laser-induced heating is explored in: (i) heating liquid media (deionized water and cell growth media [Leibovitz L15+]) to characterize the photothermal properties of the nanocomposites, (ii) in vitro experiments that explore the effects of localized heating on triple-negative breast cancer cells, and (iii) experiments in which the laser beams penetrate through chicken tissue to heat up nanocomposite samples embedded at different depths beneath the chicken skin. The resulting plasmonic laser-induced heating is explained using composite theories and heat transport models. The results show that the laser/nanocomposite interactions decrease the viability of triple-negative breast cancer cells (MDA-MB-231) at temperatures in the hyperthermia domain between 41 and 44°C. Laser irradiation did not cause any observed physical damage to the chicken tissue. The potential in vivo performance of the PDMS nanocomposites was also investigated using computational finite element models of the effects of laser/magnetite nanocomposite interactions on the temperatures and thermal doses experienced by tissues that surround the nanocomposite devices. The implications of the results are then discussed for the development of implantable nanocomposite devices for localized treatment of triple-negative breast cancer tissue via hyperthermia.

In vitro studies of Annona muricata L. extract-loaded electrospun scaffolds for localized treatment of breast cancer.

This paper presents in vitro studies of the sustained release of Annona muricata leaf extracts (AME) from hybrid electrospun fibers for breast cancer treatment. Electrospun hybrid scaffolds were fabricated from crude AME extracts, poly(lactic-co-glycolic acid)/gelatin (PLGA/Ge) and pluronic F127. The physicochemical properties of the AME extract and scaffolds were studied. The antiproliferative effects of the scaffolds were also assessed on breast cancer (MCF-7 and MDA-MB-231) and non-tumorigenic breast (MCF10A) cell lines. Scanning electron microscope micrographs revealed a random network of micro- and submicron fibers. In vitro drug release profiles, governed by quasi-Fickian diffusion at pH 7.4 and non-Fickian super case II at pH 6.7, showed initial burst AME release from the PLGA/Ge-AME and PLGA/Ge-F127/AME fibers at pH 7.4, and burst release from PLGA/Ge-F127/AME (not observed from PLGA/Ge-AME) at pH 6.7. Then, a slower, sustained release of the remaining AME from the fibers, attributed to the onset of degradation of the PLGA/Ge backbone, was observed for the next 72 hr. The cumulative release of AME was 89.33 ± 0.73% (PLGA/Ge-AME) and 51.17 ± 7.96% (PLGA/Ge-F127/AME) at pH 7.4, and 9.27 ± 2.3% and 73.5 ± 4.5%, respectively, at pH 6.7. Pluronic F127 addition increased the drug loading capacity and prolonged the sustained AME release from the fibers. The released AME significantly inhibited the in vitro growth of the breast cancer cells more than the non-tumorigenic cells, due to the induction of apoptosis, providing evidence for using pluronic F127-containing electrospun fibers for sustained and localized AME delivery to breast cancer cells.

Mechanical stimulation improves osteogenesis and the mechanical properties of osteoblast-laden RGD-functionalized polycaprolactone/hydroxyapatite scaffolds.

This article presents the results of the combined effects of RGD (arginine-glycine-aspartate) functionalization and mechanical stimulation on osteogenesis that could lead to the development of implantable robust tissue-engineered mineralized constructs. Porous polycaprolactone/hydroxyapatite (PCL/HA) scaffolds are functionalized with RGD-C (arginine-glycine-aspartate-cysteine) peptide. The effects of RGD functionalization are then explored on human fetal osteoblast cell adhesion, proliferation, osteogenic differentiation (alkaline phosphatase activity), extracellular matrix (ECM) production, and mineralization over 28 days. The effects of RGD functionalization followed by mechanical stimulation with a cyclic fluid shear stress of 3.93 mPa in a perfusion bioreactor are also elucidated. The tensile properties (Young's moduli and ultimate tensile strengths) of the cell-laden scaffolds are measured at different stages of cell culture to understand how the mechanical properties of the tissue-engineered structures evolve. RGD functionalization is shown to promote initial cell adhesion, proliferation, alkaline phosphatase (ALP) activity, and ECM production. However, it does not significantly affect mineralization and tensile properties. Mechanical stimulation after RGD functionalization is shown to further improve the ALP activity, ECM production, mineralization, and tensile properties, but not cell proliferation. The results suggest that combined RGD functionalization and mechanical stimulation of cell-laden PCL/HA scaffolds can be used to accelerate the regeneration of robust bioengineered bone structures.

Compressive deformation of Bambusa Vulgaris-Schrad in the transverse and longitudinal orientations.

This paper presents the results of theoretical and experimental studies of the compressive deformation of bamboo (Bambusa Vulgaris-Schrad) in the middle section. The deformation mechanisms are elucidated via in-situ observations of deformation in specimens oriented for loading in directions that are either longitudinal or transverse. Compressive deformation is shown to result in progressive micro-buckling and kink band formation. The onset of micro-buckling is also shown to be well predicted by an Euler buckling model. The critical loads for failure in the transverse orientation are also shown to be consistent with the conditions for shear yielding in the plies with fibers that are oriented in an orthogonal direction to the loading axis.

An investigation of the viscoelastic properties and the actin cytoskeletal structure of triple negative breast cancer cells.

An improved understanding of the evolution of cell structure and viscoelasticity with cancer malignancy could enable the development of a new generation of biomarkers and methods for cancer diagnosis. Hence, in this study, we present the viscoelastic properties (moduli and viscosities) and the actin cytoskeletal structures of triple negative breast cancer (TNBC) cells with different metastatic potential. These include: MCF-10A normal breast cells (studied as a control); MDA-MB-468 cells (less metastatic TNBC cells), and MDA-MB-231 cells (highly metastatic TNBC cells). A combination of shear assay and digital imaging correlation (DIC) techniques is used to measure the local viscoelastic properties of live breast cells subjected to constant shear stress. The local moduli and viscosities of the nuclei and cytoplasm are characterized using a generalized Maxwell model, which is used to determine the time-dependent creep responses of cells. The nuclei are shown to be stiffer and more viscous than the cytoplasms of the normal breast cells and TNBC cells. The MCF-10A normal breast cells are found to be twice as stiff as the less metastatic MDA-MB-468 breast cancer cells and over ten times stiffer than the highly metastatic MDA-MB-231 breast cancer cells. Similar trends are also observed in the viscosities of the nuclei and the cytoplasms. The measured differences in cell viscoelastic properties are also associated with significant changes in the cell cytoskeletal structure, which is studied using confocal fluorescence microscopy. This reveals significant differences in the levels of actin expression and organization in TNBC cells as they become highly metastatic. Our results suggest that the shear assay measurements of cell viscoelastic properties may be used as effective biomarkers for TNBC diagnosis and screening.

Adhesion of ligand-conjugated biosynthesized magnetite nanoparticles to triple negative breast cancer cells.

This paper presents the results of an experimental study of the adhesion forces between components of model conjugated magnetite nanoparticle systems for improved selectivity in the specific targeting of triple negative breast cancer. Adhesion forces between chemically synthesized magnetite nanoparticles (CMNPs), biosynthesized magnetite nanoparticles (BMNPs), as well as their conjugated systems and triple negative breast cancer cells (MDA-MB-231) or normal breast cells (MCF 10A) are elucidated at a nanoscale. In all cases, the BMNPs had higher adhesion forces (to breast cancer cells and normal breast cells) than CMNPs. The adhesion of LHRH-conjugated BMNPs or BSA-conjugated BMNPs to cancer cells is shown to be about 6 times to that of normal breast cells. The increase in adhesion forces between luteinizing hormone-releasing hormone, LHRH- or EphA2, a breast specific antibody(BSA)-conjugated BMNPs to breast cancer cells is attributed to van der Waals interactions between the peptides/antibodies from the conjugated nanoparticles and the over-expressed receptors (revealed using immunofluorescence staining) on the surfaces of the breast cancer. The implications of the results are discussed for the selectivity and specificity of breast cancer targeting by ligand-conjugated BMNPs.

3D printed bionic ears.

The ability to three-dimensionally interweave biological tissue with functional electronics could enable the creation of bionic organs possessing enhanced functionalities over their human counterparts. Conventional electronic devices are inherently two-dimensional, preventing seamless multidimensional integration with synthetic biology, as the processes and materials are very different. Here, we present a novel strategy for overcoming these difficulties via additive manufacturing of biological cells with structural and nanoparticle derived electronic elements. As a proof of concept, we generated a bionic ear via 3D printing of a cell-seeded hydrogel matrix in the anatomic geometry of a human ear, along with an intertwined conducting polymer consisting of infused silver nanoparticles. This allowed for in vitro culturing of cartilage tissue around an inductive coil antenna in the ear, which subsequently enables readout of inductively-coupled signals from cochlea-shaped electrodes. The printed ear exhibits enhanced auditory sensing for radio frequency reception, and complementary left and right ears can listen to stereo audio music. Overall, our approach suggests a means to intricately merge biologic and nanoelectronic functionalities via 3D printing.

Bond strengths, degree of conversion of the cement and molecular structure of the adhesive-dentine joint in fibre post restorations.

OBJECTIVES: Because fibre post restorations are influenced by multiple factors such as the types of bonding materials, the dentine region and the time under moist exposure, this study sought to determine the bond strength of endodontic restorations and its relation to the degree of conversion of the cement layer and the molecular structure of the dentine-bonded joints. METHODS: The performance of 2 etch-and-rinse (All-Bond 2 and One-Step Plus) and 2 self-etch (Clearfil SE Bond and Xeno III) adhesives at post spaces regions, after 7 d or 4 m, was evaluated. FRC Postec Plus posts were cemented to the root canal with a dual-cure resin cement (Duo-Link). Transverse sections of the tooth were subjected to push-out testing, to degree-of-conversion measurements and to hybrid layer evaluation through µ-Raman spectroscopy. RESULTS: Coronal bonding was higher than cervical and middle bonding. The hybrid layer was thicker for the etch-and-rinse systems, with thicknesses decreasing towards the middle region. The degree of conversion measured for the 3-step etch-and-rinse group after 4 m was significantly higher than that for the self-etching groups. CONCLUSIONS: Although not totally stable at the adhesive-dentine interface, the 3-step etch-and-rinse adhesive in the coronal dentine provided the best bond strength, degree of conversion of the cement and hybrid layer thickness in post restorations, in both short- and long-term analyses.

A folic acid-based functionalized surface for biosensor systems.

The performance of a biosensor depends largely on its interface with the biological system. This interface imparts a biologically relevant function to the device and provides a measure of specificity towards the biological analyte of interest. This paper documents the choice of folic acid as the functional component of a cantilever sensor to recognize nasopharyngeal (KB) cancer cells. A conjugation chemistry protocol has been outlined to deploy folic acid onto a titanium-coated sensor surface using a silane linker. The presence and biological activity of the sensor was verified by means of an immunospecific (ELISA) procedure. The overall performance of the folic acid-based cantilever sensor was measured using cancerous KB cell-binding experiments.

Sub-cellular accumulation of magnetic nanoparticles in breast tumors and metastases.

In this study, the sub-cellular accumulation of superparamagnetic iron oxide nanoparticles (SPIONs) in breast tumors and peripheral organs were investigated. MNPs were conjugated with luteinizing hormone releasing hormone (LHRH), whose receptors are expressed by most types of breast cancer cells. After the nanoparticles were injected into female nude mice bearing MDA-MB-435S.luc tumors, the mice were sacrificed to collect tumors and peripheral organs for biological and TEM analyses. LHRH conjugated SPIONs (LHRH- SPIONs) were found to accumulate in cancer cells, mainly in the primary tumors and the metastatic lungs, where they aggregated to form clusters. In contrast, most of the unconjugated SPIONs were collected in the liver cells. The results suggest that LHRH- SPIONs can be used to target cancer cells in the primary breast tumors and the lung metastases. TEM is also shown to be a useful tool for the studies of sub-cellular distributions of SPIONs in tumors and tissues.

Bounds in the sensitivity of BioMEMS devices for cell detection.

This paper presents an ongoing effort to characterize performance and reliability of micro electromechanical systems used for biomedical diagnostics (BioMEMS). In order to study the interactions of human osteosarcoma (HOS) cells with BioMEMS devices, cultures were performed on silicon (Si) surfaces as well as silicon surfaces coated with 50 nm of titanium (Ti). Cell spreading on the surfaces was observed over time for up to 2 hours. It was seen that titanium coated silicon surfaces have the potential to provide a better interface for BioMEMS devices, due to enhanced adherence and spreading of the cells on these surfaces. Atomic force microscope (AFM) cantilevers were used as cell detection sensors. These cantilevers were coated with 50nm of titanium metal to provide a cell friendly surface. Theoretical models were then developed for the prediction of the vibrational responses of the AFM cantilevers before and after cell attachment. The models were used to relate the experimentally observed changes in frequency to the number of cells that are attached on the cantilever. The bounds in the possible frequency changes were determined within a theoretical framework. From experimentally calculated values for the mass of cells, random number simulations were carried out to determine the probability of cell attachment as a function of the change in resonance frequency of the cantilever sensor. The implications of the results are then discussed for the future reliability modeling of the sensor.