Dendrimer Generation Research Articles

Synthesis and characterization of magnetized-PEGylated dendrimer anchored to thermosensitive polymer for letrozole drug delivery.

Letrozole as a target loaded drug on siliceous magnetized Fe3O4 nanoparticles grafted with high-branched dendrimers. Grafted polymer coating contained N-vinyl caprolactam as a stimulus-responsive polymer which functionalized with five generations of dendrimers containing oxime functional group. The precursors underwent PEGylating polymerization to form PEGylated dendrimer coating on the particle surface as the final carrier. The final product has the average size of ˜79 nm. The final product characterized by FT-IR, TGA, VSM, SEM-EDAX to investigate carrier features further. Some characteristic parameters in adsorption process like pH, time, the temperature investigated for letrozole using the final carrier. The physical and chemical properties of the final polymerized generations were also studied. Letrozole releasing process examined in the simulated intestinal fluid (pH = 7.4) revealed 95% of letrozole released during 25 h which also considered by Korsmeyer-Peppas equation to verify Fickian diffusion mechanism.

3D2 Self‐Assembling Janus Peptide Dendrimers with Tailorable Supermultivalency

AbstractThe self‐assembly of peptides enables the construction of self‐assembled peptide nanostructures (SPNs) with chemical composition similar to those of natural proteins; however, the structural complexity and functional properties of SPNs are far beneath those of natural proteins. One of the most fundamental challenges in fabricating more elaborate SPNs lies in developing building blocks that are simultaneously more complex and relatively easy to synthesize. Here, the development of self‐assembling Janus peptide dendrimers (JPDs) is reported, which have fully 3D structures similar to those of globular proteins. For the reliable and convenient synthesis of JPDs, a solid‐phase bifurcation synthesis method is devised. The self‐assembly behavior of JPDs is unique because only the dendrimer generation and not the weight fraction dictates the morphology of SPNs. The coassembly of two JPD building blocks provides an opportunity not only to enlarge the morphological repertoire in a predictable manner but also to discover SPNs with unusual and interesting morphologies. Because JPD assemblies have dual multivalency, i.e., supramolecular and unimolecular multivalency, the JPD system enables the statistical selection of materials with high avidity for the desired cell types and possibly any target receptors.

When dendrimers are not better - rational design of nanolayers for high-performance organic electronic devices.

Several generations of carbosilane dendrimers with quaterthiophene end groups were studied by X-ray scattering in small and wide angles, differential scanning calorimetry, polarizing optical and atomic force microscopy and molecular modelling. It was established that the semiconducting properties of such materials are determined by the formation of smectic structures in which aliphatic regions, possessing a low degree of the ordering, alternate with highly ordered herring-bone type crystallites formed by aromatic fragments. The presence of long aliphatic spacers in the dendrimers' structure allows easy formation of such crystallites. Such dendrimers assume flattened conformations, as a smectic mesophase is thermodynamically preferable in a wide temperature range. Only in the dendrimers of the fifth generation, as the density of periphery regions increases substantially, π-π stacking of oligothiophene groups is not enough to hold together, and the molecules take on a spherical shape. As a result, extended conducting conjugated regions do not form, and dendrimers of high generations possess comparatively low semiconducting properties. From the technological point of view, quaterthiophene based carbosilane dendrimers are able to form highly uniform functional films. However, the use of lower generation dendrimers is much more preferable, as additional synthetic steps for the production of higher generation compounds do not lead to the improvement of functional properties.

Thiolated DAB Dendrimers-Gold Nanoparticles as Self-Assembled Layers for the Direct Electrochemistry of HRP

In this work, three generations of a thiolated DAB dendrimer have been used as bonding-layer between electrodeposited and colloidal gold nanoparticles of several sizes to develop electrocatalytic self-assembled layers for the covalent immobilization and direct electrochemistry of horseradish peroxidase (HRP). This study covers the kinetic, electrochemical and analytical characterization of all the prepared biosensors with the aim of developing the best electrocatalytic basis for future oxidase-peroxidase bienzymatic biosensors or biosensors based on the HRP inhibition. The best results were obtained with the dendrimer of third generation and 16 nm colloidal gold nanoparticles, which showed a homogeneous electron transfer rate constant of 422 s−1. This self-assembled monolayer was the most efficient to contact with the HRP active centre and allowed to determine hydrogen peroxide at an applied potential −0.3 V in three linear ranges of 0.4-200; 200–700 and 700–4000 μM with high sensitivities of 590; 441 and 303 μA mM−1 cm−2 respectively, low detection limit of 20 nM and fast response. The obtained apparent overall rate and Michaelis-Menten constants for this optimal biosensor were 0.047 A M−1 and 1.16 mM respectively. This last one, is significantly lower than the intrinsic K'M revealing the very high enzymatic efficiency of the developed devices.

Antimicrobial efficacy and mechanism of action of poly(amidoamine) (PAMAM) dendrimers against opportunistic pathogens

The aim of this study was to investigate a range of poly(amidoamine) (PAMAM) dendrimer generations against Gram-positive and Gram-negative skin pathogens and to determine any differences in antimicrobial potency for different generations, characterising how differences in physicochemical properties influence antimicrobial efficacy. A range of tests were carried out, including viable count assays to determine half maximal inhibitory concentration (IC50) values for each dendrimer, membrane integrity studies and an inner membrane permeabilisation assay. This is supported by scanning electron microscopy imaging of the interactions observed between dendrimers and bacteria. The results of this study indicate that the antimicrobial efficacy of native PAMAM dendrimers is dependent on generation, concentration and terminal functionalities, for example, the concentration at 50% growth inhibition (MIC50) (µg/mL), against Staphylococcus aureus was between 26.77 for the G2-PAMAM-NH2 dendrimer and 2.881 for the G5-PAMAM-NH2 dendrimer. There was a strong correlation between membrane disruption and the determined biocidal activity, making it a key contributing mechanism of action. This study demonstrates that selection of the type of PAMAM dendrimer is important as their inherent antimicrobial efficacy varies according to their individual physicochemical properties. This understanding may pave the way for the development of enhanced dendrimer-based antimicrobial formulations and drug-delivery systems.

Biotin functionalized PEGylated poly(amidoamine) dendrimer conjugate for active targeting of paclitaxel in cancer

In the current study, we employed poly(amidoamine) (PAMAM) dendrimers of generation 4 (G4) to deliver paclitaxel (PTX), a poorly soluble anti-cancer agent precisely to cancer cells via its conjugation on dendrimer surface. Further, G4 PAMAM has been PEGylated (PEG) and tagged with Biotin, an essential micronutrient for cellular functions, receptors of which are overexpressed in certain cancers. The synthesized multifunctional conjugates were characterized by 1H NMR and zeta potential analysis techniques. In addition, the conjugates were evaluated in vitro in cell monolayers and 3D spheroids of biotin receptor over-expressed A549 cell line (human non-small cell lung cancer). G4 PTX PEG-Biotin conjugate penetrated at significantly higher extent in monolayers as well as spheroids as studied by flow cytometry and confocal microscopy by visualizing the cells at varied depth. The G4 PTX PEG-Biotin conjugate demonstrated higher cytotoxicity compared to free PTX and G4 PTX PEG conjugate as assessed by MTT assay in monolayers and Presto Blue assay in detached spheroidal cells. G4 PTX PEG-Biotin demonstrated significant inhibition of growth of tumor spheroids. Therefore, the newly synthesized biotin anchored PTX-conjugated dendrimer system is promising and could be further explored for efficiently delivering PTX to biotin receptor overexpressed cancers.

GENERATION DEPENDENT TARGETING POTENTIAL OF DONEPEZIL LOADED POLY (PROPYLENEIMINE) DENDRIMER THROUGH GOAT NASAL MUCOSA

Objective: In the domain of nano drug delivery, dendrimers are the most explored bioactive polymeric carrier system. The present work was aimed to study the diffusion potential of different generations of Poly (propyleneimine) (PPI) dendrimers on goat nasal mucosa in an ex vivo study and synthesize a stable dendrimer for olfactory drug delivery.Methods: The generations (3.0G, 4.0G, and 5.0G) of PPI dendrimer were synthesized, and PEGylated by MPEG 5000 and then loaded with donepezil. A comparative study was carried out among all generations in term of their drug loading capacity, stability, sustained release behaviour as well as for targeting efficacy. An ex-vivo study was carried out on Franz Diffusion Cell with goat nasal mucosa.Results: The developed G3, G4, and G5 dendrimerformulations had entrapment efficiency of 24.33±0.56%, 40.12±0.62%, and 60.4±0.6%, respectively. The nasal diffusion study revealed that 5.0G PPI dendrimer increased diffusion of donepezil up to 47% as compared to the pure solution of donepezil while 10% improvement in diffusion was seen as compared to 4.0 G PPI dendrimer. Thus obtained results claimed that the drug loading as well as targeting potential of PPI dendrimers increased with the increase in the number of generation. The investigation outcome indicated promising results of 5.0G PPI dendrimer over the 3.0G and 4.0G PPI dendrimer generations for their drug loading capacity, stability, and sustained release action.Conclusion: The 5.0G PPI dendrimer proved its superior candidature over the other lower generations of PPI dendrimers for drug delivery and drug targeting.

Label-Free and Redox Markers-Based Electrochemical Aptasensors for Aflatoxin M1 Detection.

We performed a comparative analysis of the sensitivity of aptamer-based biosensors for detection mycotoxin aflatoxin M1 (AFM1) depending on the method of immobilization of DNA aptamers and method of the detection. Label-free electrochemical impedance spectroscopy (EIS) and differential pulse voltammetry (DPV) for ferrocene labeled neutravidin layers were used for this purpose. Amino-modified DNA aptamers have been immobilized at the surface of polyamidoamine dendrimers (PAMAM) of fourth generation (G4) or biotin-modified aptamers were immobilized at the neutravidin layer chemisorbed at gold surface. In the first case the limit of detection (LOD) has been determined as 8.47 ng/L. In the second approach the LOD was similar 8.62 ng/L, which is below of allowable limits of AFM1 in milk and milk products. The aptasensors were validated in a spiked milk samples with good recovery better than 78%. Comparative analysis of the sensitivity of immuno- and aptasensors was also performed and showed comparable sensitivity.

Effect of magnetic fluid hyperthermia with dendrimer coated iron oxide nanoparticles on breast cancer in BALB/c mice

Introduction: Magnetic fluid hyperthermia (MFH) is a promising therapeutic method in cancer therapy with using magnetic nanoparticles (NPs). In this study, we assessed the effect of MFH on mechanisms of cell death in murine breast cancer cell line (MC4-L2) and also the treatment of breast tumor in BALB/C mice using four generation dendrimer coated iron oxide nanoparticles (G4@IONPs). Materials and Methods: Immediately after MFH, the viability of cells was assessed in all groups (MFH+NPs, only MFH, only NPs, control) by MTT assay. In order to determine the number of apoptosis and mRNA copies for Bax and Bcl-2 in the cells after MFH, TUNEL assay and RT-PCR were performed, respectively. The mice were exposed three times during twenty minutes to an MFH (12 kA/m, 300 kHz) after intertumoral injection of 5mg G4@IONPs. The temperature during MFH was monitored with an infrared thermometer (FLIR Systems). Tumor volume was measured during 28 days after MFH. Histopathology, Immunohistochemical staining, and TUNEL assay were performed in the liver and tumor tissues. Results: Cell viability percentage in the group of MFH+NPs decreased significantly (33%, P<0.05) while the viability in other groups had no any significant change. Also, the number of apoptotic cells and Bax/Bcl-2 ratio in MFH+NPs increased significantly. The MFH led to significantly reduce the volume of the tumor 30 days after the treatment compared with control mice (saline injection) (p < 0.05). tissue destruction obviously was seen in tumor histopathology of MFH+NPs mice. CD31 as angiogenesis marker decreased in treated tumors compared with control ones and furthermore, apoptosis significantly increased in treated tumor tissues. Conclusion: Our study showed MFH with G4@IONPs could demolish the cancer cells mainly because of increasing the apoptosis and regulating the apoptotic genomes including Bax and Bcl-2. MFH can applied as a clinical anti-cancer strategy due to inhibition of tumor angiogenesis.

Peripherally functionalized based dendrimers as the template for synthesis of silver nanoparticles and investigation the affecting factors on their properties

Today, dendrimers (D) were introduced as a versatile template for the synthesis of nanoparticles (NPs). In this work, the stable silver nanoparticles (AgNPs) is successfully synthesized through the chemical reduction of AgNO3 using NaBH4 as a reducing agent. Synthesis of AgNPs was performed in the presence of different generations of citric acid-based dendrimers (G1, G2 and G3) and hydroxyl-terminated citric acid-based dendrimers (G1-OH, G2-OH and G3-OH). High-resolution transmission electron microscopy, electron diffraction and energy-dispersive X-ray analysis were used to characterize the synthesized AgNPs. UV–Vis results were used for the qualitative study of the synthesized AgNPs properties. With varying the molar ratio of dendrimer/Ag+, generations of dendrimers and the pH of the solution, the size and size distribution of AgNPs could be easily controlled at room temperature. The average diameter of the synthesized AgNPs in the presence of Gn-OH was in the range of 8–20 nm. Results show that G1-OH alkaline medium with 1:1 molar ratio of D/Ag is the optimum condition for the synthesis of AgNPs. All the obtained results from this study showed that controlling the medium conditions allows AgNPs with the desired size to be obtained.

A novel magnetic heterogeneous catalyst based on decoration of halloysite with ionic liquid-containing dendrimer

A magnetic catalyst is synthesized through growth of dendrimer of generation 3 (G3) on the surface of halloysite (Hal) nanotubes followed by decoration of dendrimer terminal groups with ionic liquid (IL) and incorporation of Fe species. The structure of the catalyst was confirmed by using several characterization techniques. Moreover, the catalytic activity of the catalyst for oxidation of benzaldehydes to the corresponding benzoic acids in the presence of hydrogen peroxide was investigated. Notably, to improve the yield of the reaction, β-cyclodextrin (β-CD) was employed as phase transfer agent. The contribution of dendrimer and IL to the catalysis was confirmed by comparing the catalytic activity of the catalyst with that of control the catalysts (the catalyst without IL, Fe species and dendrimer). Furthermore, the effect of dendrimer generation was elucidated by comparing the catalytic activities of the catalysts prepared by growth of dendrimers of G1, G2 and G3 on Hal. Studying the recyclability of the catalyst, it was found that the catalyst could be recovered and recycled for several reaction times with slight loss of leaching of Fe species.

Electroactive magnetic nanoparticles under magnetic attraction on a microchip electrochemical device

Abstract This work focused on the introduction of electrochemical moieties (electroactive molecules) onto the surface of magnetic nanoparticles (NPs) based on carbodiimide coupling chemistry and the influence of magnetic attraction at the working electrode surface on their electrochemical behaviour. The magnetic NPs were first functionalized with polyamidoamine (PAMAM) dendrimer generation 0 and then with ferrocenecarboxylic acid (Fc) as electroactive molecule. Colorimetric titration, zeta potential measurements and infrared spectroscopy proved the effective conjugation of PAMAM and Fc onto NPs. The conjugation of Fc onto the NPs was also evidenced by voltammetry as it resulted in a half-peak potential shift from 0.328 V for free Fc to 0.590 V after coupling. A transition from a reversible to an irreversible behaviour was also observed. Finally, an external magnetic field was applied on Fc-conjugated NPs to attract them onto the working electrode of a microchip electrochemical device, and the resulting modifications of the electrochemical behaviour were studied. Compared to Fc dispersed in solution, the current peak height of Fc-conjugated NPs was 2-fold higher under magnetic attraction. The mechanism of electrochemical reaction was investigated and was found to be irreversible. Surprisingly, the reaction was diffusion-controlled upon attraction.

Click synthesis of glycosylated porphyrin-cored PAMAM dendrimers with specific recognition and thermosensitivity

Glycoporphyrin dendrimers have received increasing attentions due to their distinct physical and chemistry properties, such as fluorescence and water solubility. They also acted as a promising photodynamic therapy (PDT) sensitizer and used in the study of carbohydrate-protein interaction. In this study, different generations of porphyrin-cored dendrimers consisting of glycosylated siloxane-poly (amido amine) typed dendron (PP-Si-PAMAM-Dm-Lac, m = 1, 2, and 3), multifunctional specific-targeting sensitizers, had been synthesized via click reaction. The structure of PP-Si-PAMAM-Dm-Lac was characterized by 1H NMR, GPC, FT-IR, UV-vis and fluorescence analyses. This glycoporphyrin dendrimers, not only obtained high fluorescence quantum yield and singlet oxygen production efficiency, but also showed specific recognition of lectin and remarkable temperature-responsive property (20–80 °C). These properties proved a facile click synthetic strategy of glycosylated siloxane-poly (amido amine) typed dendrimers with multiple functions as a promising tumor-selective photsensitizer (PS) for PDT and also allow applications in highly sensitive fluorescent probes over a larger temperature window.

Hyperbranched Polyamidoamine Surfactants: Synthesis, Characterization and Evaluation as Biocides

AbstractDifferent generations of cationic hyperbranched quaternary ammonium polyamidoamine dendrimers (PAMAM) with methyl ester end group (G-0.5, G 0.5, G1.5 and G 2.5) were synthesized. Preparation of these dendrimers was carried out via alternative steps of an aza Michael addition reaction (of piperazine as core center molecule) and amidation reaction by ethylene diamine. Each aza Michael addition step was followed by a quaternization step using alkyl bromide with different chain length (4, 8 or 12) carbon atoms. The chemical structures of the prepared dendrimers were confirmed using FTIR, 1H-NMR spectra and elemental analysis for two generations as representative compounds. Also their surface activity has been studied and their surface parameters including surface and interfacial tension, emulsification power, critical micelle concentration, effectiveness, efficiency, maximum surface excess and minimum surface area were determined. The prepared quaternized dendrimers were tested as antimicrobial agents against different strains of bacteria, yeast and fungi. The results showed a significant antimicrobial efficacy of the synthesized surfactants.

Dendrimer-Stabilized Gold Nanoflowers Embedded with Ultrasmall Iron Oxide Nanoparticles for Multimode Imaging-Guided Combination Therapy of Tumors.

Development of multifunctional theranostic nanoplatforms with improved diagnostic sensitivity and therapeutic efficiency of tumors still remains a great challenge. A unique multifunctional theranostic nanoplatform based on generation 5 (G5) poly(amidoamine) dendrimer–stabilized gold nanoflowers (NFs) embedded with ultrasmall iron oxide (USIO) nanoparticles (NPs) for multimode T 1‐weighted magnetic resonance (MR)/computed tomography (CT)/photoacoustic (PA) imaging–guided combination photothermal therapy (PTT) and radiotherapy (RT) of tumors is reported here. G5 dendrimer–stabilized Au NPs and citric acid–stabilized USIO NPs are separately prepared, the two particles under a certain Fe/Au molar ratio are mixed to form complexes, the complexes are exposed to Au growth solution to form NFs via a seed–mediated manner, and the remaining dendrimer terminal amines are acetylated. The formed dendrimer‐stabilized Fe3O4/Au NFs (for short, Fe3O4/Au DSNFs) have a mean diameter of 99.8 nm, display good colloidal stability and cytocompatibility, and exhibit a near‐infrared absorption feature. The unique structure and composition of the Fe3O4/Au DSNFs endows them with a high r 1 relaxivity (3.22 mM−1 s−1) and photothermal conversion efficiency (82.7%), affording their uses as a theranostic nanoplatform for multimode MR/CT/PA imaging and combination PTT/RT of tumors with improved therapeutic efficacy, which is important for translational nanomedicine applications.

Optimized poly(amidoamine) coated magnetic nanoparticles as adsorbent for the removal of nonylphenol from water

In this study, different generation of poly(amidoamine) (PAMAM) coated magnetic iron oxide nanoparticles were successfully synthesized via divergent growth approach of dendrimer for the removal of nonylphenol (NP) from water. The characterization of synthesized nanoparticles was performed by XRD, FTIR, TEM, FE-SEM, EPX, and VSM. The results suggested that there is a direct correlation between the number of dendrimer generation and its adsorption capacity; however, the rising generation >10 could not enhance NP removal efficiency, significantly. The 10th generation of PAMAM-MNP was modified by 4-aminophenol (MNP-G10-pAP) to enhance its adsorption capacity. The kinetic studies were performed after the determination of optimal adsorption conditions (pH, 7; Detention time, 60 min). It was found that Dubinin–Radushkevich (D–R) isotherm and pseudo-second order model are perfectly stimulated the adsorption behavior and kinetic rate of NP uptake. Furthermore, the NP removal efficiencies of 70, 67, 63 and 65% were observed for distilled water, drinking water, well water and treated wastewater, respectively. Finally, it was revealed that the synthesized product had acceptable reusability in eight times and NP removal efficiency decreased by just 15%.

A Comparative Study on the Photophysical and Photochemical Properties of Dyes in the Presence of Low Generation Amino-terminated Polyamidoamine Dendrimers.

The photophysical and photochemical properties of the xanthene dyes mercurochrome (MCr) and eosin-Y (Eos); and the phenazine dye safranine-O (SF) are evaluated in the presence of amino-terminated polyamidoamine (PAMAM) dendrimers of low generations. The dendrimers produce a red shift in the UV-vis absorption spectra of the dyes, which increases with concentration and the size of the PAMAM molecule. The Stern-Volmer plots of fluorescence quenching for xanthenic dyes present a downward curvature. It is ascribed to a static mechanism involving a dye-dendrimer binding. A non-linear fitting of the SV plots allows the calculation of the binding constants. For SF, the fluorescence is only slightly quenched by PAMAMs and the SV plots are linear. The binding constants are in the order Kbind (SF) ≪ Kbind (Eos) < Kbind (MCr). The difference must be due to important specific structural effects. A decrease in the triplet lifetime and an increase in the absorption of the semireduced form of the dyes are observed in the presence of dendrimers. While for the two xanthene dyes, the rate constants reach the diffusional limit for G2 and G3, for SF they are one order of magnitude lower. This is explained by a different quenching mechanism of the two types of dyes.

Collagen-ZnO Scaffolds for Wound Healing Applications: Role of Dendrimer Functionalization and Nanoparticle Morphology.

Functionalized nanoparticle cross-linked collagen scaffolds offer improved properties to biomaterials and regenerated tissues, as influence of nanoparticle shape on collagen scaffold has received little attention. The present study evaluates the role of ZnO nanoparticle shape (sphere, rod, hexagonal, needle, flower, star, circular disk, doughnut, and cube) on collagen self-assembly. The nanoparticle was prepared by using coprecipitation method and subsequently functionalized with triethoxysilane poly(amidoamine) dendrimer generation 1 (TES-PAMAM-G1 or G1) on the nanoparticle surface. The self-assembly process of collagen, facilitated by EDC-NHS cross-linking, led to stable ZnO-TES-PAMAM-G1-collagen scaffolds. Physicochemical properties and biocompatibility of scaffolds were analyzed to determine the thermal, mechanical and pore size transformation and cell viability, etc. and obtained results compared against collagen scaffolds with/without EDC-NHS cross-linking. In vivo wound healing activity of ZnO-TES-PAMAM-G1-collagen scaffolds was tested on Albino rats that were subjected to excisional wounds and results were compared with control and collagen scaffold. Our findings suggested that the functionalized nanostructure mediated collagen scaffolds exhibited higher thermal (91.2 ± 0.3 °C) and mechanical stability (130.23-305.45 ± 0.1-2.0 MPa) than collagen scaffold (77.36 ± 0.5 °C and 7.96 ± 0.8 MPa). The result of in vivo wound healing study indicated that spherical shape of ZnO-TES-PAMAM -G1 NPs cross-linked collagen scaffold showed enhanced re-epithelization and faster collagen deposition than other scaffolds probably owing to their higher surface area, which led to higher grafting density on the surface. This work provides a new approach for designing nanoparticle mediated collagen scaffold for wound healing application.

High Sensitive Detection of Prostate Specific Antigen by Using Ferrocene Cored Asymmetric PAMAM Dendrimer Interface Screen Printed Electrodes

AbstractIn this study, electrochemical immunosensors were developed for the detection of prostate specific antigen (PSA) using ferrocene (Fc) and polyamidoamine dendrimer (PAMAM) constructs. The biosensor fabrication was designed by modifying the screen‐printed gold electrode (Au) with ferrocene cored dendrimers (FcPAMAM) synthesized in three different generations. The self‐assembled monolayer principle was followed, to obtain sensitive, selective and disposable electrodes. Therefore, the Au electrodes were modified with cysteamine (Cys) to obtain a functional surface for FcPAMAM dendrimers to bind. Dendrimer generations were attached to this surface using a cross‐linker (glutaraldehyde) so that a suitable surface was obtained for binding of biological components. The Monoclonal PSA antibody (anti‐PSA) was immobilized on the Au electrode surface which coated with dendrimer, and (Au/Cys/FcPAMAM/anti‐PSA) biosensing electrode was obtained. The PSA detection performances of electrochemical impedance spectroscopy (EIS) and Amperometry based immunosensors exhibited very low detection limits; 0.001 ng mL−1 and 0.1 pg mL−1, respectively. In addition, EIS and Amperometry based biosensors using Au/Cys/FcPAMAM/anti‐PSA sensing electrode were represented excellent linear ranges of 0.01 ng mL−1 to 100 ng mL−1 and 0.001 ng mL−1 to 100 ng mL−1. In order to determine the applicability recovery and selectivity tests were performed using three different proteins in human serum.

Multifunctional Cholesterol-modified Dendrimers for Targeted Drug Delivery to Cancer Cells Expressing Folate Receptors

We present here the development of cholesterol (Chol)-modified dendrimer system for targeted chemotherapy of folate (FA) receptor-expressing cancer cells. In our study, poly(amidoamine) (PAMAM) dendrimers of generation 5 (G5) were functionalized step-by-step with Chol, fluorescein isothiocyanate (FI), and FA via a poly(ethylene glycol) (PEG) spacer (PEG-FA), and then acetamide to shield their remaining surface amines. The synthesized G5.NHAc-Chol-FI-PEG-FA (for short, G5-CFPF) dendrimers were utilized to encapsulate 10-hydroxycamptothecin (HCP), a hydrophobic anticancer drug. We find that each G5-CFPF dendrimer can encapsulate 13.8 HCP molecules. The complexes show a slower release profiles of HCP in a pH-dependent manner than the control complexes formed using the same dendrimers without Chol under the same conditions. Thanks to the targeting role played by FA, the complexes display a specific inhibition efficacy to FA receptor-expressing cervical cancer cells. The designed Chol-modified dendrimers may be adopted as a promising carrier for application in targeted cancer therapy.