Liposome-tethered supported lipid bilayer platform for capture and release of heterogeneous populations of circulating tumor cells.

Because of scarcity, vulnerability, and heterogeneity in the population of circulating tumor cells (CTCs), the CTC isolation system relying on immunoaffinity interaction exhibits inconsistent efficiencies for all types of cancers and even CTCs with different phenotypes in individuals. Moreover, releasing viable CTCs from an isolation system is of importance for molecular analysis and drug screening in precision medicine, which remains a challenge for current systems. In this work, a new CTC isolation microfluidic platform was developed and contains a coating of the antibody-conjugated liposome-tethered-supported lipid bilayer in a developed chaotic-mixing microfluidic system, referred to as the "LIPO-SLB" platform. The biocompatible, soft, laterally fluidic, and antifouling properties of the LIPO-SLB platform offer high CTC capture efficiency, viability, and selectivity. We successfully demonstrated the capability of the LIPO-SLB platform to recapitulate different cancer cell lines with different antigen expression levels. In addition, the captured CTCs in the LIPO-SLB platform can be detached by air foam to destabilize the physically assembled bilayer structures due to a large water/air interfacial area and strong surface tension. More importantly, the LIPO-SLB platform was constructed and used for the verification of clinical samples from 161 patients with different primary cancer types. The mean values of both single CTCs and CTC clusters correlated well with the cancer stages. Moreover, a considerable number of CTCs were isolated from patients' blood samples in the early/localized stages. The clinical validation demonstrated the enormous potential of the universal LIPO-SLB platform as a tool for prognostic and predictive purposes in precision medicine.

Electrically Responsive, Nanopatterned Surfaces for Triggered Delivery of Biologically Active Molecules into Cells.

Polyelectrolyte multilayers (PEMs) assembled layer-by-layer have emerged as functional polymer films that are both stable and capable of containing drug molecules for controlled release applications. Most of these applications concentrate on sustained release, where the concentration of the released molecules remains rather constant with time. However, high-efficiency delivery requires obtaining high local concentrations at the vicinity of the cells, which is achieved by triggered release. Here, we show that a nanopatterned PEM platform demonstrates superior properties with respect to drug retention and triggered delivery. A chemically modified block copolymer film was used as a template for the selective deposition of poly(ethylene imine) and a charged derivative of the electroactive poly(3,4-ethylenedioxythiophene) together with a drug molecule. This nanopatterned PEM shows the following advantages: (1) high drug loading; (2) enhanced retention of the bioactive molecule; (3) release triggered by an electrochemical stimulus; (4) high efficacy of drug delivery to cells adsorbed on the surface compared to the delivery efficacy of a similar concentration of drug to cells suspended in a solution.

Glycan Stimulation Enables Purification of Prostate Cancer Circulating Tumor Cells on PEDOT NanoVelcro Chips for RNA Biomarker Detection.

A glycan-stimulated and poly(3,4-ethylene-dioxythiophene)s (PEDOT)-based nanomaterial platform is fabricated to purify circulating tumor cells (CTCs) from blood samples of prostate cancer (PCa) patients. This new platform, phenylboronic acid (PBA)-grafted PEDOT NanoVelcro, combines the 3D PEDOT nanosubstrate, which greatly enhances CTC capturing efficiency, with a poly(EDOT-PBA-co-EDOT-EG3) interfacial layer, which not only provides high specificity for CTC capture upon antibody conjugation but also enables competitive binding of sorbitol to gently release the captured cells. CTCs purified by this PEDOT NanoVelcro chip provide well-preserved RNA transcripts for the analysis of the expression level of several PCa-specific RNA biomarkers, which may provide clinical insights into the disease.

Ultrathin Cell-Membrane-Mimic Phosphorylcholine Polymer Film Coating Enables Large Improvements for In†Vivo Electrochemical Detection.

Resisting biomolecule adsorption onto the surface of brain-implanted microelectrodes is a key issue for in vivo monitoring of neurochemicals. Herein, we demonstrate that an ultrathin cell-membrane-mimic film of ethylenedioxythiophene tailored with zwitterionic phosphorylcholine (EDOT-PC) electropolymerized onto the surface of a carbon fiber microelectrode (CFE) not only resists protein adsorption but also maintains the sensitivity and time response for in vivo monitoring of dopamine (DA). As a consequence, the as-prepared PEDOT-PC/CFEs could be used as a new reliable platform for tracking DA in vivo and would help understand the physiological and pathological functions of DA.

Cross-Linked Fluorescent Supramolecular Nanoparticles as Finite Tattoo Pigments with Controllable Intradermal Retention Times.

Tattooing has been utilized by the medical community for precisely demarcating anatomic landmarks. This practice is especially important for identifying biopsy sites of nonmelanoma skin cancer (NMSC) due to the long interval (i.e., up to 3 months) between the initial diagnostic biopsy and surgical treatment. Commercially available tattoo pigments possess several issues, which include causing poor cosmesis, being mistaken for a melanocytic lesion, requiring additional removal procedures when no longer desired, and potentially inducing inflammatory responses. The ideal tattoo pigment for labeling of skin biopsy sites for NMSC requires (i) invisibility under ambient light, (ii) fluorescence under a selective light source, (iii) a finite intradermal retention time (ca. 3 months), and (iv) biocompatibility. Herein, we introduce cross-linked fluorescent supramolecular nanoparticles (c-FSNPs) as a "finite tattoo" pigment, with optimized photophysical properties and intradermal retention time to achieve successful in vivo finite tattooing. Fluorescent supramolecular nanoparticles encapsulate a fluorescent conjugated polymer, poly[5-methoxy-2-(3-sulfopropoxy)-1,4-phenylenevinylene] (MPS-PPV), into a core via a supramolecular synthetic approach. FSNPs which possess fluorescent properties superior to those of the free MPS-PPV are obtained through a combinatorial screening process. Covalent cross-linking of FSNPs results in micrometer-sized c-FSNPs, which exhibit a size-dependent intradermal retention. The 1456 nm sized c-FSNPs display an ideal intradermal retention time (ca. 3 months) for NMSC lesion labeling, as observed in an in vivo tattoo study. In addition, the c-FSNPs induce undetectable inflammatory responses after tattooing. We believe that the c-FSNPs can serve as a "finite tattoo" pigment to label potential malignant NMSC lesions.

Diversity of sugar acceptor of glycosyltransferase 1 from Bacillus cereus and its application for glucoside synthesis.

Glycosyltransferase 1 from Bacillus cereus (BcGT1) catalyzes the transfer of a glucosyl moiety from uridine diphosphate glucose (UDP-glucose) to various acceptors; it was expressed and characterized. The specificity of acceptors was found to be broad: more than 20 compounds classified into O-, S-, and N-linkage glucosides can be prepared with BcGT1 catalysis. Based on this work, we conclude that the corresponding acceptors of these compounds must possess the following features: (1) the acceptors must contain at least one aromatic or fused-aromatic or heteroaromatic ring; (2) the reactive hydroxyl or sulfhydryl or amino group can attach either on the aromatic ring or on its aliphatic side chain; and (3) the acceptors can be a primary, secondary, or even a tertiary amine. Four representative acceptors-fluorescein methyl ester, 17-ß-estradiol, 7-mercapto-4-methylcoumarin, and 6-benzylaminopurine-were chosen as a candidate acceptor for O-, S-, and N-glucosidation, respectively. These enzymatic products were purified and the structures were confirmed with mass and NMR spectra. As all isolated glucosides are ß-anomers, BcGT1 is confirmed to be an inverting enzyme. This study not only demonstrates the substrate promiscuity of BcGT1 but also showed the great application prospect of this enzyme in bioconversion of valuable bioactive molecules.

Step-Economical Syntheses of Functional BODIPY-EDOT π-Conjugated Materials through Direct C-H Arylation.

Palladium-catalyzed direct C-H arylations of 4,4-difluoro-4-bora-3a,4a-diaza-s-indacene (BODIPY) with 3,4-ethylenedioxythiophene (EDOT) derivatives at relatively low temperature (60 °C) provide moderate to good yields (47%-72%) of products having potential applications in fluorescent bioimaging and organic optoelectronics.

Silicon nanowire field-effect-transistor based biosensors: from sensitive to ultra-sensitive.

Silicon nanowire field effect transistors (SiNW-FETs) have shown great promise as biosensors in highly sensitive, selective, real-time and label-free measurements. While applications of SiNW-FETs for detection of biological species have been described in several publications, less attention has been devoted to summarize the conjugating methods involved in linking organic bio-receptors with the inorganic transducer and the strategies of improving the sensitivity of devices. This article attempts to focus on summarizing the various organic immobilization approaches and discussing various sensitivity improving strategies, that include (I) reducing non-specific binding, (II) alignment of the probes, (III) enhancing signals by charge reporter, (IV) novel architecture structures, and (V) sensing in the sub-threshold regime.

Rapid construction of an effective antifouling layer on a Au surface via electrodeposition.

A new approach to immobilize zwitterionic molecules rapidly and highly efficiently on a gold surface applies aniline-based electrodeposition. The zwitterion-functionalized antifouling surface enables a decrease of the adsorption of non-specific proteins by 95% from fetal bovine serum (FBS, 10%).

Preparation of high-performance water-soluble quantum dots for biorecognition through fluorescence resonance energy transfer.

An improved method for the synthesis of high-performance and water-soluble quantum dots (QDs) involving the encapsulation of mercaptosuccinic acid coated QDs (MSA-QDs) with poly(diallyldimethylammonium chloride) (PDDA) followed by their direct photoactivation with fluorescent radiation near 295 K to yield PDDA-coated QDs (PDDA-QDs) has been demonstrated. The quantum yield (QY) of the PDDA-QDs was significantly improved from 0.6 (QY of MSA-QDs) to 48%. By using this synthetic strategy, highly photoluminescent PDDA-QDs of varied size were readily prepared. The surface properties of PDDA-QDs and MSA-QDs were extensively characterized. The highly luminescent and positively charged PDDA-QDs serve as a useful and convenient tool for protein adsorption. With a Δ(5)-3-ketosteroid isomerase adsorbed PDDA-QD complex, the biorecognition of steroids was demonstrated through the application of fluorescent resonance energy transfer.

Water-soluble germanium nanoparticles cause necrotic cell death and the damage can be attenuated by blocking the transduction of necrotic signaling pathway.

Water-soluble germanium nanoparticles (wsGeNPs) with allyamine-conjugated surfaces were fabricated and emit blue fluorescence under ultraviolet light. The wsGeNP was physically and chemically stable at various experimental conditions. Cytotoxicity of the fabricated wsGeNP was examined. MTT assay demonstrated that wsGeNP possessed high toxicity to cells and clonogenic survival assay further indicated that this effect was not resulted from retarding cell growth. Flow cytometric analysis indicated that wsGeNP did not alter the cell cycle profile but the sub-G1 fraction was absent from treated cells. Results from DNA fragmentation and propidium iodide exclusion assays also suggested that apoptotic cell death did not occur in cells treated with wsGeNP. Addition of a necrosis inhibitor, necrostatin-1, attenuated cell damage and indicated that wsGeNP caused necrotic cell death. Cell signaling leads to necrotic death was investigated. Intracellular calcium and reactive oxygen species (ROS) levels were increased upon wsGeNP treatment. These effects can be abrogated by BAPTA-AM and N-acetyl cysteine respectively, resulting in a reduction in cell damage. In addition, wsGeNP caused a decrease in mitochondrial membrane potential (MMP) which could be recovered by cyclosporine A. The cellular signaling events revealed that wsGeNP increase the cellular calcium level which enhances the production of ROS and leads to a reduction of MMP, consequentially results in necrotic cell death.