Enhanced selective immobilization of biomolecules onto solid supports coated with semifluorinated self-assembled monolayers

Potential-Independent Intracellular Drug Delivery and Mitochondrial Targeting

In this study, two types of the fluoroamphiphile analogs were synthesized and self-assembled into the "core-shell" micellar nanocarriers for intracellular delivery and organelle targeting. Using the fluorescent dyes or vitamin E succinate as the cargo, the drug delivery and targeting capabilities of the fluoroamphiphiles and their micelles were evaluated in the cell lines, tumor cell spheroids, and tumor-bearing mice. The "core-fluorinated" micelles exhibited favorable physicochemical properties and improved the cellular uptake of the cargo by around 20 times compared to their "shell-fluorinated" counterparts. The results also indicated that the core-fluorinated micelles underwent an efficient clathrin-mediated endocytosis and a rapid endosomal escape thereafter. Interestingly, the internalized fluoroamphiphile micelles preferentially accumulated in mitochondria, by which the efficacy of the loaded vitamin E succinate was boosted both in vitro and in vivo. Unlike the popularly used cationic mitochondrial targeting ligands, as a charge-neutral nanocarrier, the fluoroamphiphiles' mitochondrial targeting was potential independent. The mechanism study suggested that the strong binding affinity with the phospholipids, particularly the cardiolipin, played an important role in the fluoroamphiphiles' mitochondrial targeting. These charge-neutral fluoroamphiphiles might have great potential to be a simple and reliable tool for intracellular drug delivery and mitochondrial targeting.

Reduction-Sensitive Fluorinated-Pt(IV) Universal Transfection Nanoplatform Facilitating CT45-Targeted CRISPR/dCas9 Activation for Synergistic and Individualized Treatment of Ovarian Cancer

Compared to traditional clustered regularly interspaced short palindromic repeat (CRISPR)/CRISPR-associated protein 9 (Cas9) system, CRISPR/dead Cas9 (dCas9) system can precisely regulate endogenous gene expression without damaging the host gene, representing a greater potential for cancer therapy. Cancer/testis antigen 45 (CT45) is proved to enhance platinum-based chemosensitivity for individualized ovarian cancer therapy. However, the development of a single nanocarrier codelivering CRISPR/dCas9 system and chemotherapeutics for synergistic cancer therapy still faces challenges. Herein, a reduction-sensitive fluorinated-Pt(IV) universal transfection nanoplatform (PtUTP-F) is developed for the CT45-targeted CRISPR/dCas9 activation to achieve synergistic and individualized treatment of ovarian cancer. Overcoming multiple physiological barriers, PtUTP-F condensed gene can efficiently transfect into different cells including 293T cells, A2780, SKOV3, A549, and A2780/cisplatin (DDP) cancer cells, which is superior to Lipofectamine 6000. With the responsive release of gene and Pt(II) in the intracellular reducing microenvironment, PtUTP-F/dCas9-CT45 can generate CRISPR/dCas9 activation of CT45 expression for protein phosphatase 4C (PP4C) activity inhibition to hinder the DNA repair pathway and thus enhances the sensitivity to Pt(II) drugs for individualized A2780 tumor therapy. The PtUTP-F not only represents a powerful nanoplatform for CRISPR/dCas9 system delivery but also initiates a novel strategy for synergistic and individualized treatment of CRISPR/dCas9-based gene therapy with chemotherapy.

A fluorinated low-molecular-weight PEI/HIF-1α shRNA polyplex system for hemangioma therapy

RNAi technology targeting HIF-1α could benefit hemangioma therapy effectively and FPEI polyplexes which could inhibit the expression of HIF-1α at the translational level can provide a practicable strategy for clinical hemangioma treatment in the future.

Probing the single pair rupture force of supramolecular quadruply hydrogen bonding modules by nano-adhesion measurement

Studying quadruply hydrogen bonding (QHB) module interactions in materials matrices presents a significant challenge because a wide variety of non-covalent interactions may be relevant. Here we introduce a method of surface modification with DeUG (7-deazaguanine urea), DAN (2,7-diamido-1,8-naphthyridine) and UPy (2-ureido-4[1H]-pyrimidone) modules to form self-assembled monolayers (SAMs) on a glass surface. The QHB interactions under mechanical stress were investigated by measuring adhesion force using PS-DAN (DAN modified polystyrene), PBMA-DeUG (DeUG modified poly butyl methacrylate) and PBA-UPy (UPy modified poly butyl acrylate) as adhesion promoters. A mechanical lap-shear test was used to evaluate the fracture resistance of QHB heterocomplexes. The maximum load at fail showed that QHB interaction contributed significantly (72%) to overall adhesion. For the QHB modified glass surface, using a polymer modified with its complementary QHB partner greatly facilitated their pairing efficiency, up to 40% for DAN-DeUG. A general method from which single pair ruptures force of QHB modules could be obtained using thermodynamic data obtained from solution chemistry was proposed. Using this method, the single pair rupture force for UPy–UPy was measured as 160 pN, and the single pair rupture force for DAN-DeUG was obtained as 193 pN.

Quadruply hydrogen bonding interactions under mechanical stress were investigated by measuring adhesion force using PS-DAN, PBMA-DeUG and PBA-UPy as adhesion promoters. Results showed QHB interaction contributed significantly (72%) of overall adhesion.

Tuning Oleophobicity of Silicon Oxide Surfaces with Mixed Monolayers of Aliphatic and Fluorinated Alcohols

We demonstrate the formation of mixed monolayers derived from a microwave-assisted reaction of alcohols with silicon oxide surfaces in order to tune their surface oleophobicity. This simple, rapid method provides an opportunity to precisely tune the constituents of the monolayers. As a demonstration, we sought fluorinated alcohols and aliphatic alcohols as reagents to form monolayers from two distinct constituents for tuning the surface oleophobicity. The first aspect of this study sought to identify a fluorinated alcohol that formed monolayers with a relatively high surface coverage. It was determined that 1H,1H,2H,2H-perfluoro-1-octanol yielded high quality monolayers with a water contact angle (WCA) value of ∼110° and contact angle values of ∼80° with toluene and hexadecane exhibiting both an excellent hydrophobicity and oleophobicity. Tuning of the oleophobicity of the modified silicon oxide surfaces was achieved by controlling the molar ratio of 1H,1H,2H,2H-perfluoro-1-octanol within the reaction mixtures. Surface oleophobicity progressively decreased with a decrease in the fluorinated alcohol content while the monolayers maintained their hydrophobicity with WCA values of ∼110°. The simple and reliable approach to preparing monolayers of a tuned composition that is described in this article can be utilized to control the fluorocarbon content of the hydrophobic monolayers on silicon oxide surfaces.

Osteogenic Surface Modification Based on Functionalized Poly-P-Xylylene Coating

The biotechnology to immobilize biomolecules on material surfaces has been developed vigorously due to its high potentials in medical applications. In this study, a simple and effective method was designed to immobilize biomolecules via amine-N-hydroxysuccinimide (NHS) ester conjugation reaction using functionalized poly-p-xylylene coating on material surfaces. The NHS ester functionalized coating is synthesized via chemical vapor deposition, a facile and solvent-less method, creating a surface which is ready to perform a one-step conjugation reaction. Bone morphogenetic protein 2 (BMP-2) is immobilized onto material surfaces by this coating method, forming an osteogenic environment. The immobilization process is controlled at a low temperature which does not damage proteins. This modified surface induces differentiation of preosteoblast into osteoblast, manifested by alkaline phosphatase (ALP) activity assay, Alizarin Red S (ARS) staining and the expression of osteogenic gene markers, Alpl and Bglap3. With this coating technology, immobilization of growth factors onto material surface can be achieved more simply and more effectively.

Synthesis and properties of chemiluminescent acridinium ester labels with fluorous tags

Acridinium dimethylphenyl esters are highly sensitive chemiluminescent labels that are used in clinical diagnostics. Light emission from these labels is triggered with alkaline peroxide in the presence of the cationic surfactant cetyltrimethylammonium chloride (CTAC). CTAC compresses emission times of these labels to <5 seconds and also increases overall light yield 3-4 fold. The observed enhancement in acridinium ester chemiluminescence (light yield) is quite sensitive to the polarity of the micellar interface. In the current study, we report the synthesis of new acridinium ester labels with fluorous tags of varying fluorine content and their chemiluminescence in the presence of cationic micelles of CTAC, anionic micelles of sodium perfluorooctanoate (SPFO) as well as mixed micelles of CTAC and SPFO. These studies indicate that in the presence of the mixed micelle system of CTAC and SPFO and at low mole fractions of SPFO, polarity of the mixed micelle interface is lower than that of CTAC leading to a greater enhancement of chemiluminescence for both fluorinated acridinium esters as well as a structurally analogous but non-fluorinated acridinium ester. Chemiluminescence stability of the fluorinated acridinium esters was either comparable to or better than the stability of the non-fluorinated acridinium ester. Non-specific binding to paramagnetic microparticles was higher for fluorinated acridinium esters requiring a surfactant wash to reduce their non-specific binding to the same extent as that observed for the non-fluorinated acridinium ester.

"HFP" fluorinated cationic lipids for enhanced lipoplex stability and gene delivery

Although a great number of cationic lipids have been designed and evaluated as gene delivery systems, there is still a need for improvement of nonviral vectors. Recently, cationic lipids incorporating terminal fluoroalkyl segments ("FHP" lipids) have been described to display remarkable transfection potency. Here, we describe the synthesis of a new family of fluorinated triblock cationic lipids in which a fluorous segment lays between the cationic and the lipophilic parts of the molecule ("HFP" lipids). The compounds were designed so their self-assembly would offer enhanced resistance toward the host's degradation mechanisms mediated by lipophilic insertion. Self-assembly properties of these cationic lipids were evaluated at the air-water interface where they collapse in a highly ordered liquid phase. The HFP lipids efficiently condense DNA, and the resulting lipoplexes display enhanced resistance to amphiphilic agents when compared to nonfluorinated or FHP cationic lipids. Transfection properties of the fluorinated vectors, alone or as mixtures with different helper lipids (DOPE and a fluorinated analogue of DOPE), were then investigated on different cell lines (BHK-21, HepG2, and HeLa) and compared to those of the reference cationic lipid DOTAP. Data show that impermeabilization of the lipidic phase by fluorous segments alter significantly the gene transfection activities. Remarkably, incorporation of DOPE within the lipoplexes provides the particles with high gene transfection activity without reducing their resistance to amphiphilic agents.

Grading the commercial optical biosensor literature-Class of 2008: 'The Mighty Binders'

Optical biosensor technology continues to be the method of choice for label-free, real-time interaction analysis. But when it comes to improving the quality of the biosensor literature, education should be fundamental. Of the 1413 articles published in 2008, less than 30% would pass the requirements for high-school chemistry. To teach by example, we spotlight 10 papers that illustrate how to implement the technology properly. Then we grade every paper published in 2008 on a scale from A to F and outline what features make a biosensor article fabulous, middling or abysmal. To help improve the quality of published data, we focus on a few experimental, analysis and presentation mistakes that are alarmingly common. With the literature as a guide, we want to ensure that no user is left behind.