Folate Conjugates Research Articles

Targeted delivery and apoptosis induction of trans-resveratrol-ferulic acid loaded chitosan coated folic acid conjugate solid lipid nanoparticles in colon cancer cells

The present study is aimed to study and to evaluate the colon cancer targeting efficacy of chitosan-coated-trans-resveratrol (RSV) and ferulic acid (FER) loaded SLNs (solid lipid nanoparticles) that conjugated with folic acid (FA) (C-RSV-FER-FA-SLNs) in suitable models (in vitro). The FA conjugation is performed using co-encapsulation method of stearic acid. Similarly, the prepared SLNs are exhibited better stability even under acidic conditions to exhibit their potentials to use as drug delivery system. Further, the optimized formulations (SLNs) are tested for physiochemical characterizations, which include FTIR, XRD, 1HNMR, particle size, zeta potential, and drug release. In vitro anti-cancer studies using HT-29 cells including, fluorescence staining, flow cytometry, and western blot analysis revealed that the C-RSV-FER-FA-SLNs effectively involved and increased cytotoxicity in cancer cells that leads to induction of apoptosis as compared to free RSV-FER. Thus, it is reported that, the good stability under acidic conditions of this C-RSV-FER-FA-SLNs may serve as a promising candidate for novel nanodrug formulations in cancer therapy.

Preparation, characterization and release studies of folic acid from inulin conjugates

Folic acid a synthetic form of folate, is the oxidized form of folate which acts as a coenzyme in one carbon transfer reactions required in the biosynthesis of DNA and RNA and its deficiency could be related to diseases such as neural tube defects, Alzheimer’s disease, pregnancy complications and cancer. Inulin is a polydisperse polysaccharide comprising mostly of fructosyl fructose units. An oxidized derivative of this inulin was prepared and used as a complexing agent for folic acid to obtain a polysaccharide bound folic acid conjugate. The aldehyde content and degree of oxidation of the oxidized inulin were determined by acid-base titrations. All the products were characterized by sophisticated spectroscopic and thermal methods of analysis. Release studies of folic acid from conjugates were carried out in different pH media and the results demonstrate the pH-sensitive behavior of the inulin-based delivery system towards the controlled release of folic acid.

New 55Co-labeled Albumin-Binding Folate Derivatives as Potential PET Agents for Folate Receptor Imaging.

Overexpression of folate receptors (FRs) on different tumor types (e.g., ovarian, lung) make FRs attractive in vivo targets for directed diagnostic/therapeutic agents. Currently, no diagnostic agent suitable for positron emission tomography (PET) has been adopted for clinical FR imaging. In this work, two 55Co-labeled albumin-binding folate derivatives-[55Co]Co-cm10 and [55Co]Co-rf42-with characteristics suitable for PET imaging have been developed and evaluated. High radiochemical yields (≥95%) and in vitro stabilities (≥93%) were achieved for both compounds, and cell assays demonstrated FR-mediated uptake. Both 55Co-labeled folate conjugates demonstrated high tumor uptake of 17% injected activity per gram of tissue (IA/g) at 4 h in biodistribution studies performed in KB tumor-bearing mice. Renal uptake was similar to other albumin-binding folate derivatives, and liver uptake was lower than that of previously reported [64Cu]Cu-rf42. Small animal PET/CT images confirmed the biodistribution results and showed the clear delineation of FR-expressing tumors.

Antitumor efficacy of Folic Acid conjugated Polymeric Nanoparticles of SN-38 after oral delivery

The objective of the present research was to develop folic acid conjugated polymeric nanoparticles (FCsPNP) and to investigate its therapeutic effectiveness in xenograft Colon tumor models after oral delivery. Chitosan coated PLGA nanoparticles (CsPNP) were prepared by polyelectrolyte complexation method and it was further conjugated with Folic acid. Optimized formulation was investigated for particle size, zeta potential, polydispersity index (PdI), % entrapment drug loading and in vitro release. The morphology was observed by SEM and TEM images. Tumor regression studies were conducted on Balb/c mice implanted with Colo-26 cells. FCsPNP were successfully prepared and optimized. In vitro parameters viz. Particle size, Zeta potential, PdI were found to be optimum. The in vitro % release is directly correlated with the nature of polymers and folate conjugation. In vivo tumor regression studies found the formulations to be less toxic than Irinotecan hydrochloride (IHCl). CsPNP and FCsPNP were successfully prepared and evaluated for antitumor efficacy after oral delivery. FCsPNP were more effective in the colon tumor treatment and found to be less toxic than IHCl thus making it a potential drug delivery candidate for future anticancer therapy.
 Keywords: Nanoparticles, Xenograft colon tumor, Chitosan, Irinotecan hydrochloride

Theranostic Nanoprobe Mediated Simultaneous Monitoring and Inhibition of P-Glycoprotein Potentiating Multidrug-Resistant Cancer Therapy.

Multidrug resistance is a major cause of failure in the clinical cancer therapy, in which the overexpression of P-glycoprotein (P-gp) plays a crucial role. Herein, we fabricate a theranostic nanoprobe with the function of simultaneous detection and inhibition of P-gp to diagnose and combat multidrug-resistant cancer in vitro and in vivo. For constructing the nanoprobe, elacridar modified quantum dots (QDs-Ela), acting as a gatekeeper, are grafted onto the doxorubicin (DOX) loaded, folic acid (FA) decorated mesoporous silica nanoparticles (MSNs). Upon targeted uptake by multidrug-resistant cancer cells, Bel-7402/ADR are used as a model, the acidic environment results in QDs-Ela removal from the nanoprobe, and subsequent DOX release. The removed QDs-Ela could specifically combine with P-gp in the cancer cell membrane and inhibit their active sites, which prevents the efflux of intracellular DOX and increases the retention of DOX. Another way, the fluorescence intensity of the binding QDs-Ela quantifies the P-gp expression level. Subsequently, in vitro and in vivo experiments both demonstrate the enhanced multidrug-resistant cancer therapy efficacy, i.e., nanoprobe has 10 times better curative effect than free DOX. In addition, due to the conjugation of FA, the nanoprobe exhibits a selective cell targeting ability to Bel-7402/ADR cells. This nanoplatform paves a new avenue for the accurate treatment of multidrug-resistant cancers.

Chitosan-mediated green synthesis and folic-acid modification of CuS quantum dots for photoacoustic imaging guided photothermal therapy of tumor

CuS nanomaterials capped with artificial organic-molecules or polymers have been well demonstrated as efficient photothermal nanoagents for the therapy of tumor, but their biocompatibility and target ability should be improved. To address these problems, we have used chitosan (CS) as the biomacromolecule model and surface ligands to prepare CuS quantum dots (QDs) via a simple co-precipitation method. CuS-CS QDs are then conjugated with folic acid (FA). The resulting CuS-CS-FA QDs are composed of hexagonal phase nanodots with sizes of about 4 nm. FA modification process has no apparent influence on the size, phase and composition of the QDs. Furthermore, the zeta potential and infrared spectroscopy confirm the efficient conjugation of FA. CuS-CS-FA QDs exhibit strong near-infrared photoabsorption and high photothermal efficiency (47.0%). As a result of the presence of CS ligand and FA modification, CuS-CS-FA QDs have good biocompatibility and relatively high cellular uptake efficacy. When CuS-CS-FA QD dispersion is injected intravenously into the tumor-bearing mice, the photoacoustic imaging reveals that CuS-CS-FA QD can be efficiently targeted and accumulated in the tumor and reach the peak dose at 60 min. The irradiation of 1064-nm laser (1.0 W cm−2, 10 min) results in the efficient inhibition of tumor growth, without treatment-induced toxicity. Therefore, CuS-CS-FA QDs have great potential to become biocompatible multifunctional nanoagents for imaging guided therapy of tumor.

Abstract 226: Optimization of folate receptor alpha-targeting tunable drug conjugates

Abstract We have integrated a family of innovative technologies with an aligned set of properties into Tunable Drug Conjugates (TDCs). TDCs are made up of a targeting moiety (e.g. small molecules, peptides, antibodies or antibody fragments), combined with our proprietary Silicon-based linkers (SiLinkers) and novel Payload Cassette (PC) designs which allow for delivery of multiple payloads, preferentially Conditionally Active Payloads (CAPs). CAPs are cytotoxic moieties which cannot readily permeate into normal cells due to their charged state at physiological pH of 7.4; however, at the more acidic pH of the endosome or the tumor microenvironment, the charge is neutralized enabling the CAP to readily permeate into and accumulate within the cancer cells. Our goal is to establish a beneficial Therapeutic Index (TI) and dosing flexibility by creating TDCs around a rapid payload release/rapid systemic clearance approach. Therefore, SiLinker/CAP constructs are designed to concentrate payload in the targeted tumor cell and associated tumor microenvironment while minimizing systemic payload release and rapidly clearing the parent TDC. Folate Receptor alpha (FRα) is overexpressed in multiple cancers, most notably, ovarian, endometrial, and NSCLC. Our optimized FRα-targeting TDCs use folic acid as the ligand and deliver various triple- and hexa-CAP cassettes. The various CAPs were selected from different target classes in order to allow for optimized treatment of different cancer types. We will present comparative cellular data, in vivo xenograft studies in KB, OV90 and IGROV1 models, as well as DMPK parameters of our lead FRα-TDCs. Using our triple- and hexa-PCs, we have achieved cures in in vivo xenograft studies which were durable and lasted even after treatment was stopped. We also demonstrate that in vivo our hexa-PC shows superior efficacy compared to our triple-PC in the moderate FRα expressing models. Based on our data, we believe that the combined properties of our innovative CAP-TDCs and rapid payload release/rapid systemic clearance approach will further increase TI, differentiate from other Drug Conjugates, and ultimately provide a compelling addition to existing Drug Conjugate technologies. Citation Format: Sara C. Sigler, Vinayak Gupta, Hanh N. Nguyen, Michael K. Rood, Jutta Wanner, Doug S. Werner. Optimization of folate receptor alpha-targeting tunable drug conjugates [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 226.

Abstract 216: pro-Pyrrolobenzodiazepine (pro-PBD) bioconjugates, the legacy: Design and synthesis of pro-PBD conjugates containing self-immolative substituted disulfide linkers

Abstract Naturally occurring pyrrolo[2,1-c][1,4]benzodiazepines (PBDs) are a group of highly potent antitumor antibiotics, isolated from various streptomycin species. PBDs covalently bond and cross-link with discrete sequences of base pairs in the minor groove of DNA. A wide range of synthetic PBDs and PBD dimers have been shown to be highly potent cytotoxic agents, and have been used as payloads in antibody drug conjugates (ADCs). However, all PBDs as stand-alone agents or as delivered via small molecule drug conjugates (SMDCs), cause undesired off-target toxicity. Recently, we designed folate conjugated pro-PBDs, masking the imine moiety with its synthetic precursors: namely, 1,3-oxazolidine carbamate and an aromatic amine. The 1,3-oxazolidine carbamate provided a conjugation site for attachment of pro-PBD to a targeting ligand. After delivery to the targeted cell and internalization, reductive cleavage of the linker system results in the generation of a 1,3-oxazolidine. The oxazolidine reacts with water to form an aldehyde which subsequently reacts intramolecularly to ultimately form the PBD diazepine ring. Herein, we report the design and synthesis of folate conjugates of pro-PBDs and self-immolative sterically hindered disulfide linker systems, which pave the way toward novel, highly-specific therapeutics which have the potential to minimize off-target toxicities. One of the so designed conjugates, EC2629, satisfied all of our criteria for selection for pre-clinical development: • EC2629 shows high affinity towards FR mediated binding. • Cross-links DNA only following self-immolative release of free drug. • Picomolar potency against FR-expressing cells. • Curative activity with no weight loss in animal models. • Active against drug resistant tumor xenograft models in-vivo. • EC2629 is active against patient derived xenograft models in-vivo. • Based on high cytotoxicity and minimal off target toxicity (in-vitro & in-vivo), EC2629 is selected for pre-clinical development. • Biological evaluation of EC2629 was presented at World ADC, Berlin, Germany (March, 2018). Citation Format: Iontcho Vlahov, Longwu Qi, Hari K. Santhapuram, Garth Parham, Kevin Wang, Jeremy F. Vaughn, Spencer J. Hahn, Marilynn Vetzel, Melissa Nelson, Joseph A. Reddy, Christopher P. Leamon. pro-Pyrrolobenzodiazepine (pro-PBD) bioconjugates, the legacy: Design and synthesis of pro-PBD conjugates containing self-immolative substituted disulfide linkers [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 216.

Platinated porphyrin tailed with folic acid conjugate for cell-targeted photodynamic activity

For a precisely targeted photosensitizer, we designed and prepared a new platinated porphyrin (Pt-Por-FA) by Pt-Por tailed with folic acid (FA). The intercalation mode of Pt-Por-FA binding to ct-DNA was confirmed by UV–vis and fluorescent spectra. The singlet oxygen generation of Pt-Por-FA was evaluated through 2′, 7′-dichlorofluorescin (DCFH) method. The cellular uptake and the intracellular localization of Pt-Por-FA were studied upon A549 and HeLa cells through confocal laser scanning microscope. The results showed that the red fluorescence of porphyrin conjugate observed in HeLa cells [folate receptor (FR)–positive] was significantly stronger than that of A549 cells (FR-negative), indicating that Pt-Por-FA could target specifically the cancer cells with overexpression of FR via FR-mediated endocytosis. Pt-Por-FA successfully localized in the lysosomes of cancer cells, but Pt-Por without FA did not. Moreover, the cytotoxicity against HeLa and MDA-MB-231 cells was measured by MTT assay. The results demonstrated that Pt-Por-FA had minor cytotoxicity in the dark, but showed a obviously improving toxicity in presence of light. At the concentration of 20 μM Pt-Por-FA, the cell viabilities were only 12.0% and 26.4% with the IC50 values down to 5 μm and 12 μm against HeLa and MDA-MB-231 cells, respectively. It suggests that Pt-Por-FA could be a precisely targeted photosensitizer with over-expression of a folate receptor.

Synthesis and Preliminary Anticancer Evaluation of 6-Mercaptopurine –Methotrexate Conjugate as Possible Mutual Prodrug

Small molecules drug conjugate mutual prodrug design (SMDC) composed of folate and lethal agent conjugate, rigidly bonded via hydrophilic bridge and self immolative disulfide bond ; represent new interesting approaches for cancer treatment , the component of SMDC intended for targeting folate receptor , along with greater conservation of component until reaching the target tumor tissue . The designing and synthesis of compound VI and VIII derived from 6-Mercaptopurine (6-MP) and Methotrexate ( MTX) conjugate altogether as mutual prodrugs were processed forward successfully by multistep reaction procedures , and by Thin Layer Chromatography (TLC) for preliminary detection of products and their intermediates, along with their purity. The structures of two final compounds and their intermediates were proclaimed by melting point measurement, infrared spectrometry and ¹HNMR analysis given results greatly correspond with theoretical proposed chemical structure of synthesized compounds. Furthermore, cytotoxic activity evaluation on cell line level had been done for two final compounds against human breast tumor cell (MCF-7) and human ovarian tumor cell (SKO-3) types of cancer cell line and the results were confirmed which show greater cytotoxic tumor activity of two final compounds, while compound VI possess optimal activity proportional with increased number of 6-MP molecules.

Flower-like curcumin-loaded folic acid-conjugated ZnO-MPA- βcyclodextrin nanostructures enhanced anticancer activity and cellular uptake of curcumin in breast cancer cells.

Non-spherical structures are beneficial to advance drug delivery effectiveness compared with common spherical ones, due to increased drug loading capability, improved bonding to a vascular wall, enhanced cellular uptake efficacy and prolonged circulation times. In this study, flower-like Zinc oxide-βcyclodextrin (βCD) nanostructures functionalized by 3-mercaptopropionic acid (MPA) as a non-spherical delivery system was successfully synthesized for aqueous delivery of curcumin (CUR) to enhance its targeting, bioavailability, and release profile. Terminal carboxyl functional groups were used for the conjugation of folic acid (FA) with the aim of active targeting to folate overexpressing breast cancer cells. The in vitro experimental study and mathematical modeling of CUR release revealed a sustained release with Fickian diffusion as the major release mechanism. MTT, colony formation and Annexin-V FITC/PI assays showed the superior anticancer effect of the system compared to free CUR against breast cancer cell line MDA-MB-231 by promoting the apoptotic respond with no cytotoxic effect on HEK293 normal cells. The efficacy of targeting strategy with FA moieties was demonstrated using the augmented cellular uptake of the FA-conjugated system on overexpressed folate receptor alpha (FRα) cells (MDA-MB-468 breast cancer cell line). Furthermore, loading of CUR to the delivery systems significantly lowered the MIC values (2.5 to 5-fold) against S. aureus and E. coli the infections of which are serious problems in cancer patients. According to the results of this study, the system can serve as a promising non-spherical delivery vehicle for enhancing bioavailability and targeting of hydrophobic anticancer agents in the future.

Folic acid functionalized nanoparticles as pharmaceutical carriers in drug delivery systems.

Conventional chemotherapeutic approaches in cancer therapy such as surgery, chemotherapy, and radiotherapy have several disadvantages due to their nontargeted distributions in the whole body. On the other hand, nanoparticles (NPs) based therapies are remarkably progressing to solve several limitations of conventional drug delivery systems (DDSs) including nonspecific biodistribution and targeting, poor water solubility, weak bioavailability and biodegradability, low pharmacokinetic properties, and so forth. The enhanced permeability and retention effect escape from P-glycoprotein trap in cancer cells as a passive targeting mechanism, and active targeting strategies are also other most important advantages of NPs in cancer diagnosis and therapy. Folic acid (FA) is one of the biologic molecules which has been targeted overexpressed-folic acid receptor (FR) on the surface of cancer cells. Therefore, conjugation of FA to NPs most easily enhances the FR-mediated targeting delivery of therapeutic agents. Here, the recent works in FA which have been decorated NPs-based DDSs are discussed and cancer therapy potency of these NPs in clinical trials are presented.

N-Methylpyridylporphyrin tailed with folate conjugate as a potential lysosomal-targeted photosensitizer: Synthesis, DNA interaction, singlet oxygen and subcellular localization

In recent years, great interest has been focused on the use of photosensitizers (PS) for photodynamic therapy (PDT) as safe and effective anti-tumor drugs. As a good lysosomal-targeted drug, folic acid (FA) is highly interesting as well. [Formula: see text]-methylpyridylporphyrin tailed with folate conjugate (Me-Por-FA) was newly designed and synthesized and the structure was confirmed by UV-vis, IR, 1H NMR, MS and elemental analysis. The interaction of this porphyrin with calf thymus DNA was the intercalative binding mode, which was confirmed by ultraviolet and fluorescence spectra, and the binding constants [Formula: see text] was 6.24 × 104 L/mol. The singlet oxygen (1O[Formula: see text] generated by Me-Por-FA was determined by 1, 3-diphenylisobenzofuran (DPBF) method using tetrapyridylporphyrin (H[Formula: see text]TMPyP) as a comparison with the following order: H2TMPyP > Me-Por-FA. Stained with LysoTracker[Formula: see text] Green DND-26, Me-Por-FA was mainly distributed over the lysosomes during 4 h, but H[Formula: see text]TMPyP was not. This suggests that Me-Por-FA could be developed as a targeted photosensitizer for precise photodynamic therapy.

Folic acid conjugates of a bleomycin mimic for selective targeting of folate receptor positive cancer cells

A major challenge in the application of cytotoxic anti-cancer drugs is their general lack of selectivity, which often leads to systematic toxicity due to their inability to discriminate between malignant and healthy cells. A particularly promising target for selective targeting are the folate receptors (FR) that are often over-expressed on cancer cells. Here, we report on a conjugate of the pentadentate nitrogen ligand N4Py to folic acid, via a cleavable disulphide linker, which shows selective cytotoxicity against folate receptor expressing cancer cells.

Folic Acid-Functionalized Black Phosphorus Quantum Dots for Targeted Chemo-Photothermal Combination Cancer Therapy.

Due to the inherent limitations, single chemo or photothermal therapies (PTT) are always inefficient. The combination of chemotherapy and PTT for the treatment of cancers has attracted a great interest during the past few years. As a photothermal agent, black phosphorus quantum dots (BPQDs) possess an excellent extinction coefficient, high photothermal conversion efficacy, and good biocompatibility. Herein, we developed a photo- and pH-sensitive nanoparticle based on BPQDs for targeted chemo-photothermal therapy. Doxorubicin (DOX) was employed as a model drug. This nanosystem displayed outstanding photothermal performance both in vitro and in vivo. Folic acid conjugation onto the surface endowed this system an excellent tumor-targeting effect, which was demonstrated by the cellular targeting assay. The BPQDs-based drug delivery system exhibited pH- and photo-responsive release properties, which could reduce the potential damage to normal cells. The in vitro cell viability study showed a synergistic effect in suppressing cancer cell proliferation. Therefore, this BPQDs-based drug delivery system has substantial potential for future clinical applications.

Magnetic assisted curcumin drug delivery using folate receptor targeted hybrid casein-calcium ferrite nanocarrier

Receptor targeted nanocarriers in the multimodal delivery of cancer therapeutics with minimal side effects are being intensively researched. In this study, folate receptor targeted hybrid protein inorganic nanocarrier was investigated for magnetic-assisted curcumin drug delivery. The protein carrier, casein was hybridized with superparamagnetic calcium ferrite nanoparticles (CFNP) in which the anti-cancer drug, curcumin (Cur) was encapsulated. Finally, folic acid (FA) was conjugated to enable receptor-mediated endocytosis. The synthesized materials were characterized using XRD, FTIR, SEM, VSM and DLS analysis confirming their formulation. The drug loading parameters were optimized by Taguchi technique. Curcumin release from the carrier was studied under the influence of pH, initial drug concentrations and magnetic field. Drug release rate was higher in acidic conditions, increased drug concentrations and under the influence of magnetic field. The drug release mechanism from the carrier were proposed using different kinetic models. Biocompatibility and cytotoxicity tests were performed for the synthesized drug carrier systems using L929 murine fibroblast and MCF-7 breast cancer cells, respectively. The IC50 value reduced nearly six fold for MCF-7 cells, for casein-Cur with FA conjugation in comparison to the carrier without FA. The study clearly demonstrated casein-CFNP-Cur-FA as a novel potential formulation for targeted drug delivery.

Voxel-Based Dosimetry of Iron Oxide Nanoparticle-Conjugated 177Lu-Labeled Folic Acid Using SPECT/CT Imaging of Mice.

Several radiolabeled folic acid conjugates have been developed for targeted imaging and therapy. However, the therapeutic concept with radiolabeled folate conjugates has not yet been applied to clinical applications owing to the high renal absorbed dose. The effectiveness of targeted radionuclide therapy (TRT) depends primarily on the absorbed dose rate and on the total absorbed dose delivered to the tumor and to normal tissue. Owing to various limitations associated with organ level dosimetry, voxel-based dosimetry has become essential for the assessment of a more accurateabsorbed dose during TRT. In this study, we synthesized iron oxide nanoparticle (IONP)-conjugated radiolabeled folate (177Lu-IONP-Folate) and performed voxel-based dosimetry using SPECT/CT images of normal mice through direct Geant4 application for emission tomography (GATE) Monte Carlo (MC) simulation. We also prepared 177Lu-Folate and 177Lu-IONPs for the comparison of absorbed doses with that of 177Lu-IONP-Folate. In addition, we calculated the mean absorbed dose at the organ-level using the medical internal radiation dose (MIRD) schema. The radioactivities of all three radiotracers were mainly accumulated in the liver and kidneys immediately after injection. For the kidneys, the voxel-based absorbed doses obtained with 177Lu-IONP-Folate, 177Lu-Folate, and 177Lu-IONPs were 1.01 ± 0.17, 2.46 ± 0.50, and 0.52 ± 0.08 Gy/MBq, respectively. The renal absorbed dose decreased significantly (∼half) when 177Lu-IONP-Folate was used compared with when the 177Lu-Folate only was used. The mean absorbed dose values obtained at organ-level using the MIRD schema were comparable to voxel-based absorbed doses estimated with GATE MC. The voxel-based absorbed dose values obtained in this study of individualized activity show that the renal absorbed dose could be reduced to almost half with 177Lu-IONP-Folate. Therefore, 177Lu-IONP-Folate could be clinically applicable in the TRT of folate receptor-positive cancers in a personalized manner when using the voxel-based dosimetry method.

Selective Cell Adhesion on Peptide–Polymer Electrospun Fiber Mats

Electrospun polymer fibers are valuable for a number of applications ranging from catalysis to drug delivery. At times, lack of biocompatibility, biodegradability, and hydrophobicity presents hindrance in their use in biological applications. Aromatic amino acids are veritable precursors for biocompatible nanofibers, which could also be chemically modified with suitable addressable recognition tags to invoke specific binding events. This study presents an attractive strategy for constructing electrospun fibrous mats from dityrosine folic acid conjugate and polycaprolactone to afford a new biomaterial displaying excellent tensile properties, biocompatibility, and cell adhesion. We demonstrate that appropriate choice of peptide-to-polymer ratio gave mats with sufficient hydrophilic and better mechanical properties and allowed favorable interaction of folate receptor presenting cells with electrospun mats, while the ones lacking folate receptor did not exhibit binding. Such selectivity could be possibly invo...

An Immunohistopathologic Study to Profile the Folate Receptor Beta Macrophage and Vascular Immune Microenvironment in Giant Cell Arteritis.

Giant cell arteritis (GCA) is a chronic immune-mediated disease of medium-to-large sized arteries that affects older adults. GCA manifests with arthritis and occlusive symptoms of headaches, stroke or vision loss. Macrophages and T-helper lymphocytes infiltrate the vascular wall and produce a pro-inflammatory response that lead to vessel damage and ischemia. To date, there is no GCA biomarker that can monitor disease activity and guide therapeutic response. Folate receptor beta (FRB) is a glycosylphosphatidylinositol protein that is anchored on cell membranes and normally expressed in the myelomonocytic lineage and in the majority of myeloid leukemia cells as well as in tumor and rheumatoid synovial macrophages, where its expression correlates with disease severity. The ability of FRB to bind folate compounds, folic acid-conjugates and antifolate drugs has made it a druggable target in cancer and inflammatory disease research. This report describes the histopathologic and immunohistochemical methods used to assess expression and distribution of FRB in relation to GCAimmunopathology. Formalin-fixed and paraffin-embedded temporal artery biopsies from GCA and normal controls were stained with Hematoxylin and Eosin to review tissue histology and identify pathognomonic features.Immunohistochemistry was used to detect FRB, CD68 and CD3 expression. A microscopic analysis was performed to quantify the number of positively stained cells on 10 selected high-power-field sections and their respective locations in the arterial wall. Lymphohistiocytic (LH) inflammation accompanied by intimal hyperplasia and disrupted elastic lamina was seen in GCA with none found in controls. The LH infiltrate was composed of approximately 60% lymphocytes and 40% macrophages. FRB expression was restricted to macrophages, comprising 31% of the total CD68+ macrophage population and localized to the media and adventitia. No FRB was seen in controls. This protocol demonstrated a distinct numerical and spatial pattern of the FRB macrophage relative to the vascular immune microenvironment in GCA.

Monodisperse Au@Ag core-shell nanoprobes with ultrasensitive SERS-activity for rapid identification and Raman imaging of living cancer cells

The rapid identification of living cancer cells is highly crucial for cancer diagnosis, prognosis, and treatment monitoring. However, it is a great challenge to develop an effective way for rapid identification and imaging of cancer cells in a living state. Moreover, synthesis of monodisperse nanoparticles (NPs) with high sensitive surface-enhanced Raman scattering (SERS) activity is also a tough work. Herein, we creatively reported a convenient method to synthesize the novel NPs as the substrate of SERS sensors, which possessed a gold nanobipyramid core and silver nanorod shell. These gold nanobipyramid core and silver nanorod shell NPs (Au NBP@Ag NRs) were further modified with 4-mercaptobenzoicacid (4-MBA, Raman reporter molecule) and then conjugated with reduced bovine serum albumin (rBSA) and folic acid (FA) on their surfaces, to finally acquire Au NBP@Ag NR-MBA-rBSA-FA nanoprobes. In this system, With the enhancement factor (EF) of Au NBP@Ag NRs was about 4 × 107, it could significantly enhance Raman signal for Raman reporter molecules, and 4-MBA molecules performed high SERS signals based on their structures; the nanoprobes have favorable specificity and biocompatibility owing to the modification of rBSA which effectively avoided the nonspecific attachment of non-targeted cells. Moreover, the obtained SERS nanoprobes have excellent sensitivity for gastric cancer cells (MGC-803 cells) due to the conjugation of folic acid. Thus, the finally obtained Au NBP@Ag NR-MBA-rBSA-FA nanoprobes possess excellent detection efficiency for living MGC-803 cells. Therefore, our synthesized nanoprobes exhibit ultrasensitive SERS-activity, excellent specificity and superior cancer cells targeting ability, which could be applied for rapid identification and Raman imaging of living cancer cells via the SERS signal detection of the nanoprobes.